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Oil Filter Clogging Rule - Correlation between Mileage and Lab Test Clogging | Oil Filter change interval is widely defined as a mileage, expressed in Kilometres/Miles of the Vehicle driven. On the other hand, for convenience, repeatability and differentiation reasons, the Filter life time is evaluated in the laboratory test bench according to standard test methods. The Life Time is expressed in grams of calibrated dust injected into the filter inlet so as to clog it. The most commonly used test standard is ISO 4548-12 [7]. So far, there is no widely known and recognized relation between the service time in kilometres and the dust holding capacity according to ISO standard. The purpose of the following study was to establish a relationship between ISO standard dust capacity and the ability of the filter to successfully achieve the service interval in 90% of cases. A large number of used filters were collected and analysed in order to conduct a statistical analysis. Impacts of fuel type, engine displacement and road conditions were identified. At the end a clogging rule was established. The paper concludes that for some filter applications, it is possible to reduce the required ISO dust capacity which opens the door to filter size reduction or enhanced engine protection through higher filtration efficiency. |
Development and Validation of Numerical Model for Standardized Oberst Beam Test (ASTM E 756-98) | Currently, the simulation models in acoustics and vibrations are built considering only the main structures of the vehicle, as its basic structure (Body-in-white, BIW), doors, dashboard, and so on. To take into account the contribution of components with less influence (such as carpets, seats, sound insulation, and so on) in the behavior of the overall response of the model, the average characteristics of these materials are inserted evenly distributed in these models. However, to obtain models with better correlation levels is necessary to consider local characteristics of the application of these components. In this work was developed and numerically validated, the model that describes the standardized test of “Oberst Beam” (ASTM E 756-98) to obtain the damping of the blankets used for damping of the panel vibration. With these characteristics, in future work, is expected to be possible, also with a good correlation, consider the effect of these materials on whole vehicle. |
Numerical Simulation of the Vibro-Acoustic Behavior of a Vehicle under Operating Conditions | Currently the numerical simulations of the vibro-acoustic behavior of vehicles are built considering only major structures, such as its basic structure (body in white), doors, dashboard etc. To take into account the contribution of other components (such as trims, seats, sound insulation etc.) to the overall response of the model, the average characteristics of these materials are inserted globally in this model. However, for more correlated models is necessary to consider local characteristics of these components. This work presents the numerical procedure for simulating the effect of the structural damping of viscoelastic coatings and the acoustic absorption of the trims such that its effects can be considered in the model of the full vehicle. The operating forces applied to the model were estimated from the laboratory and road tests using the SPC/TPA technique. Furthermore, the model enables the subjective evaluation of the noise from the auralization/synthesis based on numerical frequency response functions and road test data. |
A Study on New Approach of Optimization for the Automotive Plastic Interior Parts | Carmakers have tried to lower the vehicle weight for raising fuel efficiency. This trend involves a trade-off with the vehicle stiffness. In automobile interior parts, the thickness has needed to be decreased for the weight reduction but this makes the stiffness worse. A new approach for improving the stiffness due to the weight reduction is required and various optimization methods at early development stage have been introduced currently. However, it is difficult to apply optimization for the interior parts since many interior parts' structures generally depend on the design. But as studying the structure in detail, we discovered some factors that affect the performance without depending on design. The door trim is selected for optimization item because it has many characteristics of automobile interior parts. In our case study, the factors that improve the performance of door trim without changing design are considered as fastener position and flange rib layout. The optimization process for door trim was established. Size optimization is used for Fastener position and Topology optimization is used for Flange rib layout. As a result, the 1st mode frequency is improved by about 5% and thermal displacement is reduced by about 25% in comparison with the initial model. |
DPIV Measurements of the HVAC Aerodynamics Inside a Passenger Car | DPIV (Digital Particle Image Velocimetry) measurements of the HVAC (Heat, Ventilation and Air Conditioning) system aerodynamics inside the compartment of a passenger car will be presented. The measurements were carried out in a commercial version of a car. No modifications were made to the car other than substituting the doors on the passenger side for transparent acrylic sheets. In DPIV the flow is seeded with particles with size in the order of microns and the flow is illuminated by a planar pulsed laser sheet. The particles scatter the light and one or more high speed cameras, synchronized with the laser pulses, record images of the illuminated particles. Image processing of the obtained images allows the calculation of the velocity flow field. The seeding for these experiments was produced using a custom made Laskin nozzle atomizer and olive oil. Flow velocities were measured in several vertical longitudinal and transverse planes, as well as in horizontal planes, covering very large areas inside the cabin of the car with high spatial resolution. Results showing the mean and the standard deviation of the velocity flow fields inside the cabin will be presented. The work reveals how DPIV can be used in the design and validation process of HVAC systems, in order to study the instantaneous flow fields and the main structures inside the cabin for each HVAC configuration desired. |
Research on Torsional Characteristic of Separate Frame Construction for a Light Off-Road Vehicle | A key problem of designing a light off-road vehicle with separate frame construction is to improve its torsional characteristic, which has a significant influence on the performance of the vehicle. Inevitably, a certain distortion of the body would be produced by the vibration and impact passing from the road. In present research, an analysis model of light off-road vehicle is established based on the theories and methods of finite element (FEM). The static stiffness of the body is simulated and the deformation of openings on the body, mainly the windows and the doors of the vehicle is studied. On the working conditions of torsion and braking combination, torsion and cornering combination, diagonal dangling, ultimate torsion of unilateral wheels and diagonal wheels, the static strength of separate frame construction is studied as well. The stress concentration regions are obtained according to the results of simulation. Theoretically, this paper studied the torsional characteristic of separate frame construction in terms of static stiffness and static strength and the most vulnerable regions are figured out, which offers an important support for the optimization of vehicle structure. |
Aeroacoustic Noise Generated by Air Flowing through a Slit in an HVAC System | Air flowing through a narrow slit sometimes generates noise. This phenomenon has been identified in some parts of automobile HVAC systems. The noise annoys drivers and passengers and causes deterioration in the automobile’s quality. Simply sealing the gap is a way to avoid such flow noise. In an HVAC system, however, the doors that control the air flow are openable, and the door slits, which are difficult to eliminate, emanate the noise in transient conditions. The noise is well known, but the mechanism of noise generation has not been well studied to date. Computational fluid dynamics (CFD) has been a useful tool for air flow studies, but commercial CFD programs usually use a turbulence model such as Reynolds-averaged Navier-Stokes (RANS); in addition, the flow behavior result depends on the model selected in the calculation. In this study, direct numerical simulation (DNS) of the compressible subsonic flow without a turbulence model is adopted to investigate the flow through a narrow slit and its associated noise generation mechanism. The numerical results show the relationship between the noise and the unsteady vortices created through the slit. This study also explains the process of slit noise creation by comparing the force caused by vortices from the wall to the air and the noise. |
Experimental Investigation on Mechanical Properties and Vibration Damping Frequency Factor of Kenaf Fiber Reinforced Epoxy Composite | Kenaf Fiber regarded as industrial crop for different applications. It is one of the most important plants cultivated for natural fibers globally. Natural fibers such as kenaf fibers are getting attention of researchers and industries to utilize it in different composites due to its biodegradable nature. In this present investigation mechanical properties, vibration damping frequency factor and thermogravimetric analysis of kenaf fiber reinforced epoxy composite (KFREC) have been evaluated and reported. The tests were conducted with different weight categories of kenaf fiber such as 20%, 25%, 30% and 35%. The effects of fiber content on tensile, flexural, impact strengths, hardness and thermal decomposition properties of the composite were determined. The failure mechanism and damage features of the KFREC were categorized using Scanning Electron Microscope (SEM). The results indicate that the increase in the fiber content decreases the damping vibration factor (ζ) correspondingly. The lowest value of the damping vibration factor was recorded as 0.033 for 35% weight content of Kenaf fiber in the composite. The maximum value of hardness, tensile, flexural, and impact strengths were noted as 447 BHN, 45.62 MPa, 124 kN and 13.2 J respectively and the effective thermal decomposition range was 378.64 - 442.18 °C for 35% of kenaf weight content KFREC. From the results it is identified that the kenaf fiber at 35% weight content reinforced with epoxy resin will be suitable for structural application in automobiles such as bumper beams, door panels and front modules. In addition to that the light weight nature of the kenaf fiber will help in achieving fuel economy in automobiles. |
Crash-induced Loads in Liftgate Latching Systems | Automotive liftgate latches have been subject to regulation for minimum strength and inertial resistance requirements since the late 1990’s in the US and globally since the early 2000’s, possibly due to liftgate ejections stemming from the first generation Chrysler minivans which employed latches that were not originally designed with this hazard in mind. Side door latches have been regulated since the 1960’s, and the regulation of liftgate, or back door latches, have been based largely on side door requirements, with the exception of the orthogonal test requirement that is liftgate specific. Based on benchmarking tests of liftgate latches, most global OEM’s design their latches to exceed the minimum regulatory requirements. Presumably, this is based on the need to keep doors closed during crashes and specifically to do so when subjected to industry standard tests. The focus of this paper is to understand the specific loads seen by center-mounted liftgate latches when exposed to various industry standard tests, as well as some foreseeable crash conditions currently not addressed by the standard tests. This paper explores the use of CAE analysis to understand the specific structural and inertial loads liftgate latches are exposed to in various rear and side crash tests, in order to better understand the design requirements for liftgate latches to ensure passenger compartment integrity and minimize the risk of occupant ejection through the liftgate closure. Various standard crash tests, vehicle body types and cargo load cases are explored as well. A methodology is presented which shows how the various load cases can be obtained and used for development of new liftgate latches. This paper does not deal with roll over load cases, which is a subject of ongoing research and will be presented in a subsequent paper. |
The Effects of Internal Friction on Automotive Latch and Release System Behavior | Physical tests and analysis of a typical automobile latch and outside handle release mechanism are performed to determine the effects of friction on the systems dynamic response. An automobile side door outside handle, outside handle rod linkage, and latch are mounted to a rigid fixture that is constrained by bearings to a “drop tower.” The fixture is released from controlled heights onto a compliant impact surface resulting in a constant duration acceleration transient of varying amplitude. An instrumented door latch striker is designed into the fixture to engage the latch. The pre-drop interface load between the latch and striker is adjusted allowing its effect on the dynamic behavior to be characterized. The latch position and the interface load between the latch and striker are monitored throughout the test. The results of the test show that friction forces internal to the latch significantly affect the quasistatic and dynamic behavior of the latching system. |
Understanding the Stick Slip Behavior of Plastics and Target Setting: An OEM Perspective | Automotive OEMs are aggressively using different materials for interiors due to value proposition and variety of options available for customers in market. Excessive usage of different grade plastics with zero gap philosophy can cause stick slip effect leading to squeak noise. Even though systems and subsystems are designed using best practices of structural design and manufacturing tolerances, extreme environmental conditions can induce contacts leading to squeak noise. Appropriate selection of interface material pairs can minimize the possibilities of squeak conditions. Stick-slip behavior of different plastics is discussed in the present study, along with critical parameters during material compatibility testing in a tribological test stand. Friction coefficient of different material pairs for a defined normal load and sliding velocity are analyzed for patterns to recognize squeaks versus time. An OEM perspective is presented with focus on material selection using objective metrics like coefficient of friction and set targets for raw material suppliers regarding compatible materials. In the next step, an algorithm based on machine learning approach has been developed for estimating stick-slip performance. |
Dust-Sized Sensors Could Create “Electroceuticals” | University of California, Berkeley engineers have built the first dust-sized, wireless sensors that can be implanted in the body, bringing closer the day when a Fitbit-like device could monitor internal nerves, muscles, or organs in real time. These batteryless sensors, called neural dust, can also be used to stimulate nerves and muscles, opening the door to “electroceuticals” to treat disorders such as epilepsy, stimulate the immune system, or tamp down inflammation. |
Robotic Modules Modify Their Environment for Specific Tasks | Given the exact parameters of the task at hand, a robot can assemble a car door or pack a box faster and more efficiently than a human, but such purpose-built machines are not suited for much else. With that in mind, the history of robotics research is marked by devising ways of giving machines more and more autonomy. To achieve that end, robots must be able to sense features of never-before-seen environments and know how to interact with them. |
Horsepower, kilowatts compete at 2019 GENEVA MOTOR SHOW | Is Europe getting serious about electric vehicles? Look no further than the EV-intensive 2019 Geneva motor show. There still was plenty of old-school horsepower making news at this year's Geneva motor show in early March, but there was no question it's fast becoming a kilowatt kinda world. The number of electric and electrified vehicles-concept and production-ready-on display made it abundantly clear that at least in Europe, electrification's “if” definitely is no longer a question. And the “when” appears to be pretty darn soon. Although there were legitimate newsmaking vehicle introductions all over the Geneva show, the poster child for Europe's intensifying enthusiasm for electrification had to be Honda's E Prootype (see page 10), a near-production version of the universally praised Urban EV Concept shown at Frankfurt in 2017. The Urban EV's funky front bench seat is replaced by a familiar seating setup and the twin suicide doors also have morphed into four conventionally-hinged doors, but the e Prototype remains alluringly proportioned for the European market. And its rear-drive layout indicates Honda may not intend the production version to be a dull urban-transport pod. |
Aircraft Landing Noise Reduction Liners | NASA Langley Research Center has developed two new implementations of acoustic liners for aircraft noise reduction whereby curved channels within tight spaces can be outfitted to provide noise reduction. The two implementations are flap side edge liners and landing gear door liners for airframe noise reduction. In these applications, the acoustic liner is designed primarily to reduce aircraft noise that occurs during landing, which will help aircraft comply with increasingly stringent airport noise restrictions. |
Door Latch Vulnerability to Rollover Induced Loads | Light truck and SUV rollovers often involve ground contacts at the roof rails or door sills that can induce significant vertical shear loads at the latch/striker interface. These vertical loads are not evaluated in Federal Motor Vehicle Safety Standard testing yet they are known to cause latch failures. Such failures expose both belted and unrestrained occupants to increased injury risk. An example of two such failures can be found in open literature in a single van rollover test. A simple vertical load test for latches is described by the authors and evaluated for discrimination, suitability and repeatability. This test was applied to an array of current and past generation latches found on many popular SUVs and light trucks. A large range of failure loads was encountered. A review of the structural features of the superior performing test samples suggests simple modifications that could dramatically improve performance of the remaining latches. Improved performance in this vertical load test could be expected to translate to fewer unwanted door openings and ejections in field accidents. |
Invisible Advanced Passenger-Side Airbag Door Design for Optimal Deployment and Head Impact Performance | Hard panel types of invisible passenger-side airbag (IPAB) door system must be designed with a weakened area such that the airbag will deploy through the Instrument Panel (IP) in the intended manner, with no flying debris at any required operating temperature. At the same time, there must be no cracking or sharp edges in the head impact test (ECE 21.01). If the advanced-airbag with the big difference between high and low deployment pressure ranges are applied to hard panel types of IPAB door system, it becomes more difficult to optimize the tearseam strength for satisfying deployment and head impact performance simultaneously. We introduced the ‘Operating Window’ idea from quality engineering to design the hard panel types of IPAB door applied to the advanced-airbag for optimal deployment and head impact performance. To accurately predict impact performance, it is important to characterize the strain rate. |
Grade and Gage Sensitivities to Oil-Canning Loads of a Door Assembly Considering Forming Effects | A finite element methodology, based on implicit numerical integration procedure, for simulating oil-canning tests on Door assemblies is presented. The method takes into account nonlinearities due to geometry, material and contact between parts during deformation. The simulation results are compared with experimental observations. Excellent correlation between experimental observations and analytical predictions are obtained in these tests. Armed with the confidence in the methodology, simulations on a door assembly are conducted to study the gage and grade sensitivities of the outer panel. The sensitivity studies are conducted on three different grades of steel for the outer panel. Further studies are conducted to understand the effects of manufacturing (forming operation) on the oil canning behavior of door assembly. Results demonstrate the utility of the method in material selection during pre-program design of automotive structures. |
Optimization of the Side Swing Door Closing Effort | In the automotive industry, a lot of attention has been paid to the effort required for opening/closing the doors, and for a good reason. The door closing and opening effort creates an impression in the customer's mind about the engineering and quality of the vehicle even before he or she steps into it. Although this is such an important issue, the precise quantification of what constitutes a good performance target for the door opening/closing effort, has remained somewhat elusive. Thumb rules and best practices abound in the automotive industry. Some of the rules and best practices have focused on setting certain targets for the energy required to shut the door from a small open position (around 10-15 degrees). This target can be misleading. The purpose of this paper is to present an ADAMS® simulation model that includes all the different components of the door design. The complete opening/closing motion is a result of the interaction of the different components of the door closing system, such as the latch, weather seal, energy loss due to air-binding effect, the inclination of the hinge axes, check-link etc. The analysis simulates the entire opening/closing motion and the energy/force required during this motion. Analyzing the details of the door opening/closing motion of different vehicles, and associating this information to the customer dissatisfaction figures from sources like JD Power quality survey, enables us to more precisely quantify the target performance that will result in greater customer satisfaction. |
Developments in Thermoplastic Door Modules | The use of door modules as a pre -assembled functional unit inside a car door is discussed. This includes reasons why a door module should be used and why a long glass fiber reinforced polypropylene (PP) product is a good material of choice. As an example the development of the door modules for the new Ford Fiesta is given, including the mechanical and production design of the StaMax® P long glass PP carrier. * Special attention is paid to the excellent dimensional reproducibility of this material which is critical for door module designs in which the carrier also manages the wet and dry separation (e.g. “sealed” designs). Further integration potential for future door modules is also highlighted. |
A Design Study to Determine the Impact of Various Parameters on Door Acoustics | Once the design of a door sheetmetal and accessories is confirmed, the acoustics of the door system depends on the sound package assembly. This essentially consists of a watershield which acts as a barrier and a porous material which acts as an absorber. The acoustical performance of the watershield and the reverberant sound build-up in the door cavity control the performance. This paper discusses the findings of a design study that was developed based on design of experiments (DOE) concepts to determine which parameters of the door sound package assembly are important to the door acoustics. The study was based on conducting a minimum number of tests on a five factor - two level design that covered over 16 different design configurations. In addition, other measurements were made that aided in developing a SEA model which is also compared with the findings of the results of the design study. |
A Comprehensive Study of Door Slam | As part of an ongoing technical collaboration between Ford and Rouge Steel Company, a comprehensive study of door slam event was undertaken. The experimental phase of the project involved measurements of accelerations at eight locations on the outer panel and strains on six locations of the inner panel. Although slam tests were conducted with window up and window down, results of only one test is presented in this paper. The CAE phase of the project involved the development of suitable “math” model of the door assembly and analysis methodology to capture the dynamics of the event. The predictability of the CAE method is examined through detailed comparison of accelerations and strains. While excellent agreement between CAE and test results of accelerations on the outer panel is obtained, the analysis predicts higher strains on the inner panel than the test. In addition, the tendency of outer panel to elastically buckle is examined. The implications of the buckling of the outer panel are discussed. The effects of thickness distribution and plastic strains introduced on the inner and outer panels due to forming are studied. The results show that the strains on the inner panel can be significantly influenced when forming effects are accounted for. The effect of forming on the accelerations of the outer panel can be less intuitive. This is possibly due to the buckling of the outer panel during the slam event. |
New Methods of Side Impact Simulation for Better Waveform Reproduction and Door Interaction | As a result of the severity of occupant injuries during a side impact collision, there has been an escalating demand for accurate component level side impact simulation. Three major components for accurate simulation are accurate door velocity, door to seat relative velocity, and door deformation. This paper shows data demonstrating accurate door velocity reproduction, presents test methods to passively and actively control relative seat to door velocity in a non destructive manner, and presents test methods to simulate real time door deformation in a destructive manner. All side impact waveforms include a negative acceleration, high positive accelerations, high jerk, and high frequency content that add to the complexity of this simulation. The simulated door velocity is produced by means of a MTS deceleration brake that only applies a braking force during the deceleration portion of the waveform to maximize acceleration capacity. The proposed methodologies introduce a controlled damper technology (patent pending) to actively control the transmitted forces between independent components during the simulation. |
Analysis of the Influence of the Seal Structure on Door Closing Force for SANTANA | In order to evaluate the influence of the seal structure on door closing force, nonlinear finite element method is introduced to analyze compression deformation of a door seal for SANTANA (name of the car made by Shanghai Volkswagen Co. Ltd) in this paper. The computed results show that the compression loads of the door seal are larger than the standard value of Shanghai Volkswagen Co. Ltd and the seal structure needs to be optimized. The computed results are proved by experiment. |
Vehicle Door Latch Safety Measures Based on System Dynamics | The governments of many countries have established regulations that address the issue of vehicle door safety during crash events. Depending on the regulation or specification, analytical tools may be acceptable for verifying the crashworthiness of a latching system. In those instances where actual test crashes are required for verification, analytical methods can still be used to help predict the outcome of a crash test. Two relevant analytical approaches for multibody dynamics computation are discussed in the paper. One is related to monitoring the effects of constant 30G inertia loading in all directions (spherical analysis) and another addresses inertia pulse loading of specified G levels in certain directions. In some crash situations, the latch system compliance with the regulations may be insufficient to prevent door release. To secure the door in the latched position additional safety devices can be deployed in various locations of the door latch system. One group of such devices relies on using inertia catch levers triggered by specific acceleration of vehicle door. The development and tuning of the inertia catch devices is done by analytical means followed by latch system validation during crash tests. |
Door Overbend - Design Synthesis & Analysis | This paper describes the analytical methodology for calculating the overbend needed in the door design to counteract the non-linear seal forces acting on the door header. Overbend in the door design will allow the Original Equipment Manufacturer to achieve competitive above belt flushness and gap dimensional targets at static equilibrium of the door header and weatherstrip. This method combines two analytical models of the weatherstrip and the Door-In-White (DIW) to forecast the design overbend necessary to achieve good fit and finish. These models are: 1) Seal compression-load deflection (CLD) models for each angle of attack of the weatherstrip to the door 2) A nonlinear Finite Element Analysis (FEA) model of the trimmed DIW. Bringing these two elements together to model the static equilibrium deflection, this is developed, into overbend requirements. The design synthesis process to meet the overbend design criteria is demonstrated. This method improves product quality and reduces door fit warranty by producing a product design that comprehends the inherent deflection of seal loads on the door structure. |
A Discussion on Interior Compartment Doors and Latches | Interior compartment doors are required by Federal Motor Vehicle Safety Standard (FMVSS) 201, to stay closed during physical head impact testing, and when subjected to specific inertia loads. This paper defines interior compartment doors, and shows examples of several different latches designed to keep these doors closed. It also explores the details of the requirements that interior compartment doors and their latches must meet, including differing requirements from automobile manufacturers. It then shows the conventional static method a supplier uses to analyze a latch and door system. And, since static calculations can't always capture the complexities of a dynamic event, this paper also presents a case study of one particular latch and door system showing a way to simulate the forces experienced by a latch. The dynamic simulation is done using Finite Element Analysis and instrumentation of actual hardware in physical tests. |
Simulation Methods for Door Module Design | With the automotive industry moving towards higher durability targets, reduced product development cycle time, and lower design costs, the need for simulation has never been higher. This paper explains the use of simulation techniques in the design and development of door module. A step-by-step approach to simulate a door slam event is proposed. Fatigue life estimation using simulation results is also discussed. Finally, simulation benefits are illustrated with a simulation-test case study completed at ArvinMeritor that resulted in a fatigue life improvement of more than 50%. The scope of this paper is limited to simulation methods for door slam. Test methods to collect data for door slam simulation are not discussed. |
An Experimental Investigation About Cable Efficiencies in Current Automotive Door Systems | Based on experimental and analytical research, a design tool was developed to estimate engineering parameters for side door latch inside release cables, given a pre-determined operating range. This design tool accurately estimates the cable efficiency for a set of parameters, thus significantly reducing the design time for latch and cable related engineering issues. Through testing and data analysis, the study determined the relationship between performance factors such as cable efficiency and effort losses, and design factors such as cable type, routing and loading conditions. Experimental data was used to generate curve fit equations that predict the cable efficiency for side a door latch system level development. |
Environmentally Friendly Door Sash Tape | Coating black paint on the door sash of automobiles has been a separate process from the body coating. Recently, moany automotive manufacturers are switching this secondary coating process to adhesive tape technology for various advantages. These advantages include reduction of VOC (volatile organic carbon), rationalization of assembly process, cost reduction and so on. Since this application is considered a variation of exterior decal film, most of the commercially available products are currently based on PVC (Polyvinyl chloride) film. (See Photo 1.) The automotive industry has increasingly been sensitive to the use of PVC due to its potential environmental problems. One of the problems is that the product cannot be incinerated when disposed of since it generates hydrogen chloride gas, dioxin and other toxic chlorinated organic matters. Also, reportedly its plasticizer may act as an endocrine disruptor (also known as ‘an environmental hormone’) when dissolved in water. Nitto Denko has developed an environmentally friendly polyolefin door sash tape as an alternative to the PVC tape. By optimizing polymer chemistry and film composition, the new polyolefin door sash tape exhibits high dimension stability in physical properties for a wide range of temperatures. Also, proprietary surface conditioning of this film ensures resistance to long-term outdoor exposure. An acceleration test has proved that the product retains 93% of glossiness compared to that of initial, with colorimetric change (delta E*ab) of only +0.12, for six and half years equivalent of solar ray radiation. Also, we did not detect toxic gases when we performed incineration tests. Only water vapor, carbon mono-oxide and carbon dioxide were detected in the given detection limit. This test has clearly demonstrated that the product causes significantly lower environmental damage than that of PVC. |
3D Audio Reproduction via Headrest Equipped with Loudspeakers—Investigations on Acoustical Design Criteria | This paper focuses on the analysis and evaluation of acoustical design criteria to produce a plausible 3D sound field solely via headrest with integrated loudspeakers at the driver/passenger seats in the car cabin. Existing audio systems in cars utilize several distributed loudspeakers to support passengers with sound. Such configurations suffer from individual 3D audio information at each position. Therefore, we present a convincing minimal setup focusing sound solely at the passenger’s ears. The design itself plays a critical role for the optimal reproduction and control of a sound field for a specific 3D audio application. Moreover, the design facilitates the 3D audio reproduction of common channel-based, scene-based, and object-based audio formats. In addition, 3D audio reproduction enables to represent warnings regarding monitoring of the vehicle status (e.g.: seat belts, direction indicator, open doors, luggage compartment) in spatial accordance. Furthermore, individual sound zones enable superior in-car communication between seats regardless of the current driving situation. An often overlooked topic is the acoustical privacy of in-car systems towards the exterior especially during telephony which is also tackled by the presented design as a by-product. We present how the structural shape, the assembly and alignment of the loudspeakers affects the frequency response, the effective sound pressure levels at the passenger’s ears, the inter-aural crosstalk, and the crosstalk to other seats. We further show that person affects the sound field by movements and therefore can change the overall performance. Finally, we present our approach for 3D audio reproduction for the car cabin schematically. |
CAE Support to Vehicle Audio Installation Issues | Audio CAE is an emerging area of interest for vehicle OEMs. Questions regarding early stages of the vehicle design, like choosing the possible positions for speakers, deciding the installation details that can influence the visual design, and integration of the low frequency speakers with the body & closures structure, are of interest. Therefore, at VCC, the development of the CAE methodology for audio applications has been undertaken. The key to all CAE applications is the loudspeaker model made available in the vibro-acoustic software used within the company. Such a model has been developed, implemented and verified in different frequency ranges and different applications. The applications can be divided into the low frequency ones (concerning the installation of woofers and subwoofers), and the middle/high frequency ones (concerning the installation of midrange and tweeter speakers). In the case of the woofer, it is the interaction with the body vibration that is of interest. Hence, the loudspeaker has to be used in a full vibro-acoustic Trimmed Body model. For the higher frequencies (midrange & tweeter) the body can be treated as locally reacting, if not rigid. The examples of the verification of the speaker model versus test data for a woofer mounted in a car door will be shown, together with applications to woofer installation issues. Regarding high frequencies, examples will be shown of the comparison of different grille variants and the evaluation of the position of the speaker on the sound quality at the listeners’ positions. Future developments will be discussed. |
Asian Consumers Challenging the NVH Performance of European Cars - Implications on the Product Development in the 2020ies | Sales of SUV and luxury cars on the largest market of the world - China - are growing at a high rate. The highways in large cities like Beijing or Shanghai are increasingly populated with cars from all over the world like Japan, USA, Europe and Korea and even some refined domestic brands. More than 10 million rich people can afford those cars and are skilled drivers. This huge group of potential consumers is targeted by luxury brand OEMs and by startup companies. It has been understood that these people have a high expectation of comfort. The twistbeam rear axle was replaced by multilink, double clutch transmissions were improved by comfort-mode drive programs, interior trims raised to Western standard performance levels, tyres specially developed for comfort in China, localized insulation materials and packages engineered to a one vehicle class higher level. The European avant-garde is capable of such high levels of complete vehicle NVH performance, whereas premium brands often compromise NVH with respect to high vehicle dynamics performance and passive safety requirements. Furthermore, the preference of Chinese consumers by long vehicles as a symbol of status and flaunting their riches, can also be consider a challenge for NVH performance. A longer wheelbase will require stiffer body and chassis structure to keep the ride comfort and squeak & rattle performance - to be more developed later on in the paper. At the same time Asian cars from Korea or Japan are sometimes outperforming the Europeans in terms of comfort. In future and in combination with the next evolution level of electrification and driving assistance the acceptable level of NVH annoyance will be reduced to a radically low threshold. In order to overcome the gap between this new threshold and current performances adjustments in vehicle specifications and the process to achieve those need to be implemented. The main focus is on powertrain noise, ride comfort and vibrations, rolling noise and wind noises and the overall NVH quality impression, e.g. of the door closing sound. The paper points out, which technical specifications are imperative for a good consumer reception and describes the processes that are needed for target achievement. |
Impact of Different Types of Glazing on Thermal Comfort of Vehicle Occupants | Due to intense peak summer temperatures and sunny summers in tropical countries like India etc., achieving the required thermal comfort of car occupants without compromising on fuel efficiency is becoming increasingly challenging. The major source of heat load on vehicle is Solar Load. Therefore, a study has been conducted to evaluate the heat load on vehicle cabin due to solar radiations and its impact on vehicle air-conditioning system performance with various combinations of door glasses and windscreen. The glasses used for this study are classified as green, dark green, dark gray, standard PVB (Polyvinyl Butyral) windscreen and PVB windscreen having infrared cut particles. For each glass, part level evaluation was done to find out the percentage transmittance of light of different wavelengths and heat flux through each glass. To verify the effectiveness of each glass, vehicle level air-conditioning system performance test was done in All Weather Chassis Dyno Facility for each retrofitted vehicle. To eliminate the effect of manufacturing variance while evaluating each retrofitted vehicle, only door glasses and windscreen were changed in the same vehicle keeping all other testing conditions such as ambient temperature, incident solar radiations, humidity and vehicle running pattern the same. The performance of each retrofitted vehicle was evaluated on the basis of its-soaking temperature, soaking time, grill temperature, and nose level temperature. On comparing the results of each configuration, the best door glass and windscreen configuration is proposed to improve the thermal comfort of the vehicle occupants. |
In-Situ Studies on the Effect of Solar Control Glazings on In-Cabin Thermal Environment in Hot and Humid Climatic Zones | Thermal comfort in a passenger cabin is the basic necessity of an occupant, especially in hot and humid climatic conditions. It is known that the reflective glazing solutions provide better thermal comfort inside the cabin due to significant reflection of IR part of solar radiation. However, in hot and humid climatic zones like India, significant reduction in heat load can also be achieved through cost effective solar control absorbing glazings. Thus, the present work aims to study the effect of solar control absorbing glazings on in-cabin temperatures and its impact on thermal comfort of the occupants in tropical climates. A combination of glazing sets with a range of solar energy transmission and absorption values is considered for the study. Indoor soak and cool tests are performed on a sedan model with multiple sets of solar control absorbing glass combinations. A constant ambient temperature of 38°C and solar radiation of 1000W/m2 are maintained throughout the tests. Wind speed is simulated for a vehicle running speed of 45 kmph. Net heat gain inside the cabin as a combination of various inward and outward loads of radiation through glazing is investigated. Accumulated heat is measured in terms of temperatures for comparison of various glazing sets. Reductions in heat loads are compared with experimental data of non-absorbing and reflective glazing sets available in literature. Best suitable combinations for front and back windshields, front and back side doors for the chosen vehicle are discussed in view of total solar energy transmission through the glazings and occupants thermal comfort. |
Evaluation of Laminated Side Window Glazing Coding and Rollover Ejection Mitigation Performance Using NASS-CDS | Occupant ejection has been identified as a safety problem for decades, particularly in rollover crashes. While field accident studies have repeatedly demonstrated the effectiveness of seat belts in mitigating rollover ejection and injuries, the use of laminated glass in side window positions has been suggested as a means to mitigate occupant ejection. Limited data is available on the field performance of laminated glass in preventing ejection. This study utilized 1997-2015 NASS-CDS data to investigate the reliability of the glazing coding variables in the database and determine if any conclusions can be drawn regarding the effect of different side window glazing types on occupant ejection. An initial query was run for 1997-2016 model year vehicles involved in side impacts to evaluate glazing coding within NASS-CDS. Sixteen individual cases were identified where the first-row side window glass was coded as both laminated and as in-place and holed, out-of-place and not holed, out-of-place and holed, or disintegrated from impact. NASS-CDS case summaries and photographs were reviewed and compared against original equipment manufacturer (OEM) specifications for the involved vehicles. The results demonstrated that the presence of laminated side window glass was incorrectly coded in 11 out of the 16 cases. The coding definitions were revised to query NASS-CDS for vehicles known to be equipped with standard or optional laminated glass in the first-row side windows based upon sources including the National Auto Glass Specifications (NAGS) database and vehicle manufacturer information (e.g., sales brochures, press releases, and other specifications). The new definitions were used in conjunction with the 16 previously identified side impact cases and found to correctly differentiate between the cases with and without laminated first-row side window glazing. Based upon this revised coding strategy, another NASS-CDS query was run to evaluate glazing type as it relates to rollover crashes involving 1997-2016 model year vehicles to determine the rate and frequency of front seat occupant ejection by glass type. This query resulted in a weighted 2,785,988 front seat occupants involved in a rollover, of which only 0.5% (13,640) occupants were in vehicles equipped with standard laminated front door window glass. Using the weighted occupants counts, there were 193 completely ejected and 277 partially ejected front seat occupants in vehicles equipped with standard laminated front door window glass; these numbers were based on unweighted samples of 10 or fewer. The sample sizes were too small to draw any statistically significant conclusions regarding ejection rates in rollover as a function of glazing type. The results of this study indicate that NASS-CDS glazing coding alone is not appropriate to identify the presence of laminated glass in specific vehicle window portals. This study also demonstrates that the resulting sample of field accidents is too small to assess the effectiveness of laminated glass in reducing the incidence of occupant ejection. The revised coding strategy may, however, be expanded with newer data and may be used in other databases such as Fatality Analysis Reporting System (FARS). It should be noted that, given the increased implementation of side curtain airbags in the vehicle fleet, it may become increasingly difficult to assess any individual contribution of laminated glass to occupant containment versus ejection. |
Evaluation of Functional Performance of Mechanism Using Multi Body Dynamics Simulation | The functional performance of the mechanism plays a vital role in attracting customer concentration towards the product. It is the first interface for interaction with the customer. Hence it is important to evaluate the functional performance at the time of the design phase itself in order to eliminate the possibility of an increase in proto-builds. The functional performance of a mechanism comprises parameters like, a mechanism should perform its function for which it is designed, with minimum effort required and ease in functionality. Evaluation of such parameters at the design stage involves many assumptions and this brings chance variables in the methodology. In order to eliminate these assumptions, a methodology has been developed using the multi-body dynamics (MBD) model of mechanisms like gear shifting mechanism and cabin door outer handle mechanism. The effort and displacement required to drive the mechanism were evaluated and a correlation of about 90% with the practical testing results was obtained. The same methodology was utilized to quickly optimize the existing design and reduce the effort and displacement required to drive the mechanism through the virtual model itself. |
An Analysis of the Effects of Ventilation on Burn Patterns Resulting from Passenger Compartment Interior Fires | Vehicle fire investigators often use the existence of burn patterns, along with the amount and location of fire damage, to determine the fire origin and its cause. The purpose of this paper is to study the effects of ventilation location on the interior burn patterns and burn damage of passenger compartment fires. Four similar Ford Fusion vehicles were burned. The fire origin and first material ignited were the same for all four vehicles. In each test, a different door window was down for the duration of the burn test. Each vehicle was allowed to burn until the windshield, back glass, or another window, other than the window used for ventilation, failed, thus changing the ventilation pattern. At that point, the fire was extinguished. Temperatures were measured at various locations in the passenger compartment. Video recordings and still photography were collected at all phases of the study. Although the fire origin and source were known, the vehicle burn patterns were analyzed and conclusions drawn based on the post-fire evidence regarding: ability to determine a window was open during the fire, which window was open, the effect the open window had on burn patterns and burn damage, and the ability to determine the fire origin. Thermocouple readings were plotted and analyzed post-test to study temperature characteristics during the burn tests. |
A Development and Evaluation of Optimal Fingerprint Authentication Algorithm in Vehicle Use Environment | Hyundai Motor Company mass-produced the world's first fingerprint entry and start system. This paper is a study on the evaluation method to develop and verify the optimal fingerprint authentication algorithm for vehicle usage conditions. Currently, fingerprint sensors and algorithms in the IT industry have been developed for the electronic devices, and are not suitable for the harsh environment of the vehicle and the vehicle life cycle for more than 10 years. In order to optimize the fingerprint sensor and algorithm for the vehicle, this study consisted of 3way test methods. As a result, the fingerprint system could be optimized for the vehicle and the recognition rate and security could be optimized according to the sensor authentication level. Through this study, the door handle recognition rate was improved by 25% and the start button recognition rate by 10%, and the fingerprint entry and start system was mass-produced with security level that satisfies the immobilizer regulations. |
Robustness Design to Avoid Noise on Exterior Handle System | Squeak and rattle are two undesirable occurrences during component operation and during vehicle driving condition, resulting in one of the top complains from costumers. One common grievance could happen during the user exterior handle operation and during side door closing. The exterior handle system during the operation could generate a squeak between interface parts, if materials and geometric tolerances was not been carefully designed. Also, vibration generated during door closing effort, might generate squeak between parts since the reinforcement for exterior handle touches the outer sheet metal internally. For this reason several guidelines might be included to avoid potential noise condition for this system during vehicle lifetime as correct material reduce friction between parts, taking into consideration the geometric condition between parts. Plus, coupling system on handles two pieces should also be evaluated to avoid squeak during use. Not less important, if required anti-shock material system may be applied to eliminate a clash produced between parts during excessive vibration. It is extremely important to evaluate the environment that the vehicle will be exposed since the correct material application also depend on this factor. Design parameters as materials used to produce parts, dimension geometric data and a robust technique of attachment must be analyzed. Correct material selection and tools like Dimensional Variation Analysis may be taken to identify and optimize the design to avoid noise and minimize cost. |
Coating on Striker: Low Coefficient of Friction to Avoid Creak Noise | The unpleasant noise (creak) originated from latch-striker interaction, perceived mainly when the vehicle is submitted to uneven road conditions is generated by stick-slip phenomenon mainly due materials incompatibility of contact surfaces. Generally, eliminate this incompatibility is unfeasible due technical and/or economics constrains; this scenario makes it necessary to act in other fronts to neutralize the effects of that incompatibility. Reduce the coefficient of friction from one of contact surfaces is an alternative that can be easily applied at striker through a thin thickness coating with that property. |
Practical Design Considerations for Lightweight Side Window Applications | Automotive manufacturers are requiring lightweight materials, including glazing materials to improve vehicle fuel economy and meet government mandates. Taken as a group, the area of four side windows is comparable to that of a windshield, and, therefore, can offer significant weight reduction opportunities. As glass thickness is reduced, the acoustic and stiffness properties of the glazing change. Newer developmental interlayer materials have demonstrated the capability for overcoming the reduction in performance to maintain the properties of the original heavier constructions. |
Modeling and Numerical Analysis of Automotive Aerodynamic Noise Generation and Transmission Considering Equivalent Nonlinear Sealing | Aerodynamic noise transmits through automotive window, causing great adverse influence on comfortability and noise-vibration-harshness (NVH) performance. However, the complicated external turbulent air flow, as well as the internal metal-rubber nonlinear sealing constraint, makes the mechanism of aerodynamic noise generation and transmission very difficult. Regarding the complex exterior aerodynamics-induced load and nonlinear metal-rubber interaction and constraint, an efficient two-step numerical prediction method is presented in order to study the mechanism of its generation and transmission. The first step uses the commercial ANSYS-Fluent computational fluid dynamics (CFD) analysis based on the shear stress transport (SST) - turbulence kinetic energy (k) - the rate of dissipation of turbulence kinetic energy ε (epsilon) model and Lighthill’s noise source theory. For low Mach number and high Reynolds number flow like the flow around a vehicle body, dipole source is regarded as the dominant contribution and can be obtained by the broadband noise source model. Exterior turbulent flow field of a full-scale automotive is established and near-field sound power distribution of automotive window has been obtained, which are both subsequently input to the acoustic model to investigate the noise generation mechanism. The second step consists of the numerical prediction of noise transmission through automotive window. Nonlinear spring-based surrogate model for seal nonlinear constraint is proposed and verified by modal experiment. Based on SAE J1400 reverberant-anechoic measurement standard, a numerical prediction model of the sound transmission loss (STL) is constructed using commercial vibro-acoustic solver Actran. New automotive window structural design by non-uniform density distribution is proposed to optimize the STL property. The present methodology of STL modeling and numerical prediction provides valuable instructions for performance optimization of automotive door under high speed driving condition. |
“Taguchi Customer Loss Function” Based Functional Requirements | Understanding customer expectations is critical to satisfying customers. Holding customer clinics is one approach to set winning targets for the engineering functional measures to drive customer satisfaction. In these clinics, customers are asked to operate and interact with vehicle systems or subsystems such as doors, lift gates, shifters, and seat adjusters, and then rate their experience. From this customer evaluation data, engineers can create customer loss or preference functions. These functions let engineers set appropriate targets by balancing risks and benefits. Statistical methods such as cumulative customer loss function are regularly applied for such analyses. In this paper, a new approach based on the Taguchi method is proposed and developed. It is referred to as Taguchi Customer Loss Function (TCLF). The “Taguchi Quality Loss Function (TQLF)” methodology has been used primarily to improve quality from a manufacturing standpoint, giving engineers a way to understand how process variation affects customer satisfaction. In the proposed “Taguchi Customer Loss Function (TCLF)” methodology, a similar analogy is applied for developing requirements on the design such that variation in customer preference is accounted for. Also, trade-offs can be made with other business constraints while keeping the customer dissatisfaction to minimum. Example problems are presented to demonstrate its simplicity and its potential for understanding customer clinic data. |
Eleven Instrumented Motorcycle Crash Tests and Development of Updated Motorcycle Impact-Speed Equations | Eleven instrumented crash tests were performed as part of the 2016 World Reconstruction Exposition (WREX2016), using seven Harley-Davidson motorcycles and three automobiles. For all tests, the automobile was stationary while the motorcycle was delivered into the vehicle, while upright with tires rolling, at varying speeds. Seven tests were performed at speeds between 30 and 46 mph while four low-speed tests were performed to establish the onset of permanent motorcycle deformation. Data from these tests, and other published testing, was analyzed using available models to determine their accuracy when predicting the impact speed of Harley-Davidson motorcycles. The most accurate model was the Modified Eubanks set of equations introduced in 2009, producing errors with an average of 0.4 mph and a standard deviation (SD) of 4.8 mph. An updated set of Eubanks-style equations were developed adding data published since 2009, and advancing from two equations (pillars/axles and doors/fenders) to four equations (axles, pillars/bumpers, doors, and fenders). When applied to the subject tests, the newly developed set of equations produced an average error of 3.5 mph (SD = 4.3 mph). With respect to all available data (N = 99), the equations produced an average error of 0.1 mph and a standard deviation of 5.8 mph. The errors were also analyzed for each of the four equations developed here, and confidence intervals offered. This research, which represents the first detailed analysis of Harley-Davidson motorcycles’ collision response, indicates they behave in a manner similar to previously tested motorcycles. Further, the equations developed and presented here give accident investigators a refined method for estimating the impact speed of an upright motorcycle, Harley-Davidson or otherwise, having struck an automobile with its front tire. |
Regression Analysis: A Geometric Perspective | Regression analysis is perhaps one of the most widely used statistical tools in six-sigma projects. The reason for its popularity is that it provides a formal evaluation of the relationship between one dependent variable and one or more predictors. The ordinary least squares (OLS), which is a method for estimating the parameters of the linear regression model, has some numerical properties that can be easily understood by looking at them in a geometric manner. In this paper, we discuss the fundamentals of both simple and multiple regression analysis from a geometric perspective. This approach offers an intuitive understanding of some concepts that otherwise would require a background in statistical mathematics and differential calculus. One of the topics covered in this paper is multicollinearity, whose consequences are not well understood by many practitioners. A practical example drawn from the automotive industry (body exterior quality) is used to clarify the basic notions that appear throughout the paper. This example consists of a regression analysis made over a sample of vehicles in an attempt to explain the level of customer's complaints regarding side door closing effort (dependent variable) by the actual closing effort measured in a laboratory using a standard procedure (independent variable). It is well known that closing effort, in turn, is also highly correlated with the compression load deflection (CLD) of the door seals, meaning that including both variables as predictors in the same model would produce unreliable estimates of the parameters. Unfortunately, many quality engineers disregard the effects of multicollinearity when they perform this kind of analysis. This paper is intended to draw attention to these issues in a user-friendly way. |
Standard for Safety Glazing Materials for Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land Highways - Safety Standard | Specifications, test methods, and usage provisions for safety glazing materials used for glazing of motor vehicles and motor vehicle equipment operating on land highways. |
Automotive Safety Glazing Materials | This SAE Recommended Practice is a guidance document, which covers current safety glazing materials applicable for use in motor vehicles and motor vehicle equipment. Nominal specifications for thickness, flatness, curvature, size, and fabrication details are included. This guidance document does not precede or replace customer specifications and requirements. |
Automotive Safety Glazing Materials | This SAE Recommended Practice is intended to cover current safety glazing practice applicable to safety glazing for use in motor vehicles and motor vehicle equipment. Nominal specifications for thickness, flatness, curvature, size, and fabrication details are included principally for the guidance of body engineers and designers. |
Analysis of Damage Caused to Vehicle Body Panels by Impacting Hail and Various Tools and Objects | On the 25th December 2011 there was a hail storm in the state of Victoria, Australia, which caused approximately AU$712 million worth of damage. Some of this damage was caused to passenger vehicles. The authors conducted a number of inspections of hail-damaged vehicles as a result of insurance claims being disputed or rejected on the basis that some, or all, of the alleged hail damage was not created by hail but instead created intentionally by the vehicles' owners with the use of different tools and/or objects. As a result of the inspections and investigations of potentially fraudulent claims, the authors conducted a total of 119 tests designed to replicate damage caused to vehicle body panels by impacting hail and to recreate claimed hail damage by using tools and other objects. To do so, the authors created two sizes of hail: Ø20 mm and Ø40 mm hail. A total of 15 impact tests were conducted with Ø20 mm hail. The impact speed for the Ø20 mm hail varied between 75 km/h and 144 km/h, with the average being 113 km/h. A total of 50 impact tests were conducted with Ø40 mm hail. The impact speed for the Ø40 mm hail varied between 66 km/h and 133 km/h, with the average being 101 km/h. The testing impact speeds were generally higher than the terminal velocities of the corresponding hail, so the damage observed is expected to be an over estimation of the actual damage caused by hail. The hail was projected at the test vehicle using a purpose-built projectile launching device that used a sling-like mechanism to project hail in a horizontal direction at a test vehicle. The test vehicle was a white-colored 2001 model Holden Commodore with non-metallic paint. The body panels tested were: bonnet, roof, boot, all four doors, the vehicle pillars and cant rail. High speed cameras were used to determine the impact speed of the hail. Damage was photographed and recorded. In addition to impacting the vehicle with hail, a number of different tools and objects were used to recreate man-made damage. Tools and objects used were: claw hammer (conventional), welding hammer, ball-peen hammer, mason hammer, lead ball sink in a sock, golf ball in a sock, ratchet, breaker bar, crowbar and center punch. The conducted tests revealed the following findings: 1. hail impacting the vehicle body panels will not scratch or mark the paint but the paint may chip if hail impacts the vehicle near a fold or edge of a panel; 2. dents caused by hail will cause the light to move smoothly and continuously across the dent and the light will not "break" or crease; 3. where dents were caused by tools and objects the light will crease into multiple (two or more) distinct areas as it passes over the dent; 4. scratches and/or markings in the paint were identified on dents caused by tools and objects; 5. folds and curves on the panels did not affect the size of the dent caused to the panel; using the same tool and force to impact two different body panels (A-pillar and roof) resulted in dents that were very similar in physical appearance; 6. for the same impact speed the larger Ø40 mm hail caused more damage than the Ø20 mm hail; and 7. for the same size hail the higher impact speed hail caused more damage. |
Eleven Instrumented Motorcycle Crash Tests and Development of Updated Motorcycle Impact-Speed Equations | Eleven instrumented crash tests were performed as part of the 2016 World Reconstruction Exposition (WREX2016), using seven Harley-Davidson motorcycles and three automobiles. For all tests, the automobile was stationary while the motorcycle was delivered into the vehicle, while upright with tires rolling, at varying speeds. Seven tests were performed at speeds between 30 and 46 mph while four low-speed tests were performed to establish the onset of permanent motorcycle deformation. Data from these tests, and other published testing, was analyzed using previously published equations to determine their accuracy when predicting the impact speed of Harley-Davidson motorcycles. The most accurate model was the Modified Eubanks set of equations introduced in 2009, producing errors with an average of 0.4 mph and a standard deviation (SD) of 4.8 mph. An updated set of Eubanks-style equations were developed adding data published since 2009, and further partitioning from two equations (pillars/axles and doors/fenders) to four equations (axles, pillars/bumpers, doors, and fenders). When applied to the subject tests, the newly developed set of equations produced an average error of 3.5 mph (SD = 4.3 mph). With respect to all available data (N = 99), the equations produced an average error of 0.1 mph and an SD of 5.8 mph. The errors were also analyzed for each of the four equations developed here, and confidence intervals offered. This research, which represents the first detailed analysis of Harley-Davidson motorcycles’ collision response, indicates they behave in a manner similar to previously tested motorcycles. Further, the equations developed and presented here give accident investigators a refined method for estimating the impact speed of an upright motorcycle, Harley-Davidson or otherwise, having struck an automobile with its front tire. |
Prediction of Sound Transmission through Door Seals Using the Hybrid FE-SEA Method | During the last decades, the application of noise control treatments in vehicles has targeted the main noise transmission paths to interior noise. These paths include vehicle body panels such as dash panel, doors and floor. Many improvements have been achieved on these areas, and, as a consequence, other transmission paths once thought as secondary became relevant. This is the case of the sound transmission through door seals and others sealing elements at mid and high frequencies. In this paper, the interest lies on the prediction of the transmission loss of door seals. A full nonlinear deformation/contact analysis is used to estimate the deformed geometry of a door seal in real conditions. The geometry is then used in a vibro-acoustic analysis to predict the in-situ transmission loss of the seal using a local Hybrid FE-SEA model. The channel between the door and the car structure where the seal is located is also included in the analysis. Results for the transmission loss are compared with experimental data, showing a good correlation. It is also shown that the channel is an important element of the analysis and must be taken into account. |
Innovative Robust Solutions for Lean Manufacturing in Automotive Assembly Processes | The article presents an innovative approach to the implementation of a robust design optimization solution in an automobiles assembly process. The approach of the entire project is specific to the 6 Sigma optimization process, by applying the DMAIC cycle integrated in a robust engineering approach for rendering lean the final product assembly process. According to the improvement cycle, the aspects specific for such a process are presented sequentially starting with the “Define” phase for presenting the encountered problem and continuing with the presentation of the scope of the project and its objectives. The “Improvement” cycle phase is applied by the analysis of the monitored 6 Sigma metrics (defined during the previous “Measure” phase and the cause and effect analysis, done during a brainstorming meeting developed during the “Analyze” phase). There follows a proposal for the innovative robust solution by which the assembly process is optimized. Therefore, we propose the final assembly of already painted doors on the already assembled cars with a special work-holding which is easy to handle by the human operator. The automation of designed and implemented solutions provides features of error proofing for the assembly process in the case in which the doors are not located accordingly on the work-holding locating elements, which may lead to various inconveniences during the assembly on the vehicle and/or some faults of the door quality, such as scratches or deformations because of the impacts. The initially presented process indices, for the not yet optimized process are finally evaluated after the implementation of the innovative solution for a comparative study of the initial monitoring results and after the implementation of the proposed corrective solution. This underlines the critical conclusions that are induced during the “Control” phase. The final conclusions point to the corrective / preventive actions for a sustainable and reliable optimization, which give the maximal process its overall efficiency. |
Advances in Vehicular Ad-Hoc Networks: Developments and Challenges | A Vehicular Ad Hoc Network (VANET) is a non-infrastructure based network that does not rely on a central administration for communication between vehicles. The flexibility of VANETs opens the door to a myriad of applications; however, there are also a number of computer communication challenges that await researchers and engineers who are serious about their implementation and deployment. This book tackles the prevalent research challenges that hinder a fully deployable vehicular network. This unique reference presents a unified treatment of the various aspects of VANETs and is essential for not only university professors, but also for researchers working in the automobile industry. Topics include: Architecture of vehicular ad hoc networks Communication technologies in vehicular applications Cooperative collision avoidance Geographic routing in vehicular ad hoc networks IEEE 802.11g and IEEE 802.16e technologies Information sharing in VANETs Infrastructures in vehicular communications Mobility and traffic model analysis Opportunistic networking Routing protocols in vehicular ad hoc networks |
Kiekert unveils automatic-door tech for autonomous vehicles | A new electronic side door latch is the prelude to vehicle side doors that automatically open and close on command. “Our endgame is about providing a system in which the side doors automatically open when an autonomously-driven car arrives for passengers,” said Hector Verde, Director of Product Development for the Americas at Kiekert. Those doors would also close automatically after the occupants are in the vehicle. All this could happen with just the push of a button or sensor recognition, he added. |
Researchers Uncover New Way to Control Information by Mixing Light and Sound | A Yale lab has developed a new, radio frequency processing device that allows information to be controlled more effectively, opening the door to a new generation of signal processing on microchips. |
Lightweight door module aims to trim vehicle weight | A new ultralight door architecture nets a 42.5% weight savings compared to a current production door-and that's enough to put this lightweight concept in an enviable position. “This lightweight door module has a great opportunity to be commercialized. It's not just high-tech. It's also at the right cost,” said Reuben Sarkar, Deputy Assistant Secretary for Transportation, Energy Efficiency and Renewable Energy at the U.S. Department of Energy. |
Automobile and Motor Coach Wiring | This SAE Recommended Practice covers the application of primary wiring distribution system harnesses to automotive, and Motor Coach vehicles. This is written principally for new vehicles but is also applicable to rewiring and service. It covers the areas of performance, operating integrity, efficiency, economy, uniformity, facility of manufacturing and service. This practice applies to wiring systems of less than 50 V. |
Passengers First Light Truck - A Modern Take on a Narrow Wake | Individuals in the United States consume twice as much energy as those in any other region. Solitary workday commutes in light vehicles are the leading reason for this difference. An electric vehicle design is proposed to help catalyze more social, higher occupancy, commuting habits - through application of existing technology. Performance criteria are: 1) attract passengers to the suburban front yard at 6:30 AM, 2) match market leading crash test performance, cargo capability, and sense of freedom, and 3) deliver easier parking, better acoustics and better passenger mile efficiency. A vehicle as a rolling event venue determines a large windscreen, side-by-side upright seating arrangements, and acoustic excellence -an experience where there are only good seats. These requirements force a decision to close the wake along a vertical line to form a narrow wake. The chassis is platform batteries with dual motor electric rear drive and undetermined front drive. Findings: 1 Narrow wake synergies include: a) cargo loading on a tailgate ramp to a low 0.3m (12 inch) high load floor through a 0.8m (32 inch) wide opening - as a controlled event using an onboard powered trolley, b) passengers more safely located, and c) thick rear doors that pivot concentric with the rear axle, with no chance of damaging adjacent objects. 2 A consistent driver’s eye location, as datum, provides better forward visibility past the A-Pillar and more consistent relationships between driver, passengers and vehicle safety and content delivery systems, when compared to location off fixed pedals at the firewall. 3 Collateral benefits of the eye datum include large section B-Pillars, dual diagonal cooling circuits that apply full cooling power as the sun clocks, and a smooth transition to self-driving operation. |
Intrusion Resistance of Safety Glazing Systems for Road Vehicles | This SAE Recommended Practice specifies an intrusion resistance test method for glazing systems installed in motor vehicles. Intrusion resistance performance is determined not solely by the glazing but also by the glazing attachment to the vehicle and by the vehicle structure. Therefore, the glazing/attachment/vehicle structure must be tested as a single unit. This test determines intrusion resistance only. The test applies to those materials that meet the requirements for use as safety glazing materials as specified in ANSI/SAE Z26.1 or other applicable standards. The test applies to all installation locations. |
A Test Method and Simulation Study of PMMA Glazing on Motion Deviation | For achieving vehicle light weighting, the motion deviation is calculated for substitution of PMMA glazing for inorganic glass. In this paper, a test method is proposed to measure and calculate the motion deviation of the dual-curvature glass. To simulate the dual-curvature glass, the torus surface is fitted with least square method according to the window frame data, which are measured by Coordinate Measuring Machine. By using this method, the motion deviation of PMMA glazing and inorganic glass can be calculated, which can not only validate the effectiveness of motion simulation, but also compare the performances. The results demonstrate that the performance of PMMA glazing is better than that of inorganic glass and the simulation results is validated. |
Framed Door x Fully Stamped Door | When designing a new subsystem for a new vehicle platform, technical requirements, performance targets and cost implications drive the decision process towards which concept to be adopted. If this platform is planned for worldwide introduction, local requirements and capabilities have to be put into the business equation. Among the possible design options for a Side Door Subsystem, including basically Inset doors and Limo doors with their variations, the best for the market is selected on: Commonality requirements through the platform family; Technical implications of each design concept; Technical excellence to produce parts with the required quality/cost in the local market; Costs and timing associated with each design concept; Benchmarking. This composition of factors drove the decision to adopt different design options for South America and Europe on the recently launched small car platform. This paper demonstrates the rationale of this decision making process and the positive outcomes of it. |
Average Vehicle Dimensions for Use in Designing Docking Facilities for Motor Vehicles | This SAE Recommended Practice establishes limits for empty vehicle floor heights and provides limits of vehicle dimensions for use in designing docking facilities for motor vehicles. |
Leading Edge Requirements Engineering for the Automotive Industry - With the Use of JAMA | There have been many publications about requirements management, and still organizations are struggling to show 100% coverage and traceability in a lean way. It does not start with CMMI nor SPICE. It does not end with tools like DOORs, Polarion, Codebeamer or JAMA. It does depend on the right setup and how it feels in the everyday life of an engineer. This paper defines and explains what it takes to establish leading edge requirements engineering for the automotive industry. It describes how work day integration of requirements engineering and management can be achieved. The different roles in engineering are addressed with their unique needs to support them. One 120% RQM data model is shown and explained. The necessary rollout project is designed with activities to adapt a tool to existing processes and individual tools, explain, improve, transfer as well as train/coach the engineers. The impact of and resolution for existing bypasses is discussed as well as the necessary qualification of rollout coaches. Before going in bit and byte - let’s not forget to get Product Management on board. Usability is a key for product success, so why should it be different for the tool success. Here we show how a tool need to adapt, not just to the different engineering roles but also to the interfaces of management and the rest of the tool landscape. In efficiency in use of roots in hesitation and fear of the engineers. Simple concepts are explained to introduce a creative fail-forward culture around requirements engineering. Chicken-or-Egg discussions are bypassed with a creative distinction or requirements versus specification. The activities around requirements are explained in a complete requirements lifecycle model. Necessary design levels and all RQM items are shown in and exemplary tool setup in JAMA Connect. A test driven bottom up approach is added for special use-cases. Finally it is shown how we can reduce surprises ate product release significantly with 100% traceability and integrated change management. The difference of coverage and traceability if shown and explained and how to use it to lift the readers requirements management in the 21st century. As part of the outlook, the challenge of configuration management is addresses as a problem that today is still not sufficiently supported by most requirements management tools.. |
Experimental noise and vibration analysis in an aircraft simplified hydraulic systems | Due to the great use of airplanes for transportation, it was necessary some studies to improve it, one of the most difficult problems to solve, is the noise generated by the systems. In-flight sound pressure levels can sometimes be intense and cause fatigue to the cabin crew, communication failures and discomfort to the passengers. This is often caused by the turbulent boundary layer over the aircraft body, engine noise and vibration and internal aircraft systems. The aircraft hydraulic system is responsible for moving the rudder, aileron, brakes, main door, and other components, and consequently, the noise of this system became more noticeable. This system comprises a pump, generally, located at the back of the aircraft and pipes, which are fixed along the fuselage. The pipes are connected to the fuselage using rubber mounts. Analyzing experimental measurements is possible to identify that hydraulic system contribute to the in-flight sound pressure level in the aircraft cabin. However is the connection between pipe and fuselage the main problem. In this paper, will be demonstrated a simplified methodology to analyze these noise, generated by the hydraulic system, with results of sound pressure and vibration measured in an experimental device, operated under different conditions. |
Ultra-Thin, Energy-Efficient Photodetector Integrated with Gorilla Glass | Photodetectors — also known as photosensors — contribute to the convenience of modern life. They convert light energy into electrical signals to complete tasks such as opening automatic sliding doors and automatically adjusting a cellphone’s screen brightness in different lighting conditions. Researchers are advancing photodetectors’ use by integrating the technology with durable Gorilla glass, the material used for smartphone screens that is manufactured by Corning Incorporated. |
Simulating the Static and Dynamic Response of an Automotive Weatherstrip Component | Understanding the resonant behavior of vehicle closures such as doors, hoods, trunks, and rear lift gates can be critical to achieve structure-borne noise, vibration, and harshness (NVH) performance requirements, particularly below 100Hz. Nearly all closure systems have elastomer weatherstrip components that create a viscoelastic boundary condition along a continuous line around its perimeter and is capable of influencing the resonant behavior of the closure system. This paper outlines an approach to simulate the static and dynamic characteristics of a closed-cell Ethylene Propylene Diene Monomer (EPDM) foam rubber weatherstrip component that is first subjected to a large-strain quasi-static preload with a small-strain sinusoidal dynamic load superimposed. An outline of a theoretical approach using “phi-functions” as developed by K.N. Morman Jr., and J.C. Nagtegaal [1] is introduced followed by a discussion of the material characterization that was done to construct a suitable elastomer material model for finite element analysis (FEA). Next, to validate the approach, the FEA and correlation of a simple extension specimen is presented followed by the analysis and correlation of a weatherstrip component with a complex cross sectional shape. It is observed that the static and/or dynamic response of the weatherstrip material and component can be dependent on several factors such as excitation frequency, large-strain preload, vibration amplitude, component geometry, and friction. Correlation between simulation and experimental results for dynamic stiffness and loss factor are in general agreement below 100Hz. |
Application of the Hybrid FE-SEA Method to Predict Sound Transmission Through Complex Sealing Systems | Currently, the use of numerical and analytical tools during a vehicle development is extensive in the automotive industry. This assures that the required performance levels can be achieved from the early stages of development. However, there are some aspects of the vibro-acoustic performance of a vehicle that are rarely assessed through numerical or analytical analysis. An example is the modeling of sound transmission through vehicle sealing systems. In this case, most of the investigations have been done experimentally, and the analytical models available are not sufficiently accurate. In this paper, the modeling of the sound transmission through a vehicle door seal is presented. The study is an extension of a previous work in which the applicability of the Hybrid FE-SEA method was demonstrated for predicting the TL of sealing elements. A numerical validation of simplified Hybrid FE-SEA model is performed, which is followed by the application of the method to the TL of a car door seal. A full non-linear deformation/contact analysis is used to estimate the deformed geometry of the door seal in real conditions. The geometry is then used in a vibro-acoustic analysis to predict the in-situ transmission loss of the seal using a local Hybrid FE-SEA model. The channel between the door and the car structure where the seal is located is also included in the analysis. Results for the transmission loss are compared with experimental data, showing a good correlation. |
A Computational Process for Early Stage Assessment of Automotive Buffeting and Wind Noise | A computational process for early stage vehicle shape assessment for automotive front window buffeting and greenhouse wind noise is presented. It is a challenging problem in an experimental process as the vehicle geometry is not always finalized. For example, the buffeting behavior typically worsens during the vehicle development process as the vehicle gets tighter, leading to expensive late counter measures. We present a solution using previously validated CFD/CAA software based on the Lattice Boltzmann Method (LBM). A CAD model with realistic automotive geometry was chosen to simultaneously study the potential of different side mirror geometries to influence the front window buffeting and greenhouse wind noise phenomena. A glass mounted mirror and a door mounted mirror were used for this comparative study. Interior noise is investigated for the two phenomena studied. The unsteady flow is visualized and changes in the buffeting and wind noise behavior are explored. |
Boundary Condition Effect on the Correlation of an Acoustic Finite Element Passenger Compartment Model | Three different acoustic finite element models of an automobile passenger compartment are developed and experimentally assessed. The three different models are a traditional model, an improved model, and an optimized model. The traditional model represents the passenger and trunk compartment cavities and the coupling between them through the rear seat cavity. The improved model includes traditional acoustic models of the passenger and trunk compartments, as well as equivalent-acoustic finite element models of the front and rear seats, parcel shelf, door volumes, instrument panel, and trunk wheel well volume. An optimized version of the improved acoustic model is developed by modifying the equivalent-acoustic properties. Modal analysis tests of a vehicle were conducted using loudspeaker excitation to identify the compartment cavity modes and sound pressure response to 500 Hz to assess the accuracy of the acoustic models. The optimized acoustic model is also coupled with a structural finite-element model of the trimmed body to evaluate the effect of body panel flexibility on the interior sound pressure response. The optimized acoustic model is found to exhibit the best correlation in terms of the predicted sound pressure FRF response at the passenger compartment interior locations and at the compartment boundary surfaces. |
Evaluation of the Aerodynamic and Aeroacoustic Response of a Vehicle to Transient Flow Conditions | A vehicle on the road encounters an unsteady flow due to turbulence in the natural wind, unsteady wakes of other vehicles and as a result of traversing through the stationary wakes of roadside obstacles. Unsteady effects occurring in the sideglass region of a vehicle are particularly relevant to wind noise. This is a region close to the driver and dominated by separated flow structures from the A-pillar and door mirrors, which are sensitive to unsteadiness in the onset flow. Since the sideglass region is of particular aeroacoustic importance, the paper seeks to determine what impact these unsteady effects have on the sources of aeroacoustic noise as measured inside the passenger compartment, in addition to the flow structures in this region. Data presented were obtained during on-road measurement campaigns using two instrumented vehicles, as well as from aeroacoustic wind tunnel tests. Conventional admittance functions relating oncoming flow yaw angle to cabin noise response are generally not suitable due to the non-linear steady state characteristics obtained in the wind tunnel, i.e. the cabin noise does not vary with yaw angle in a linear fashion under steady-state conditions. Therefore two alternative approaches were used based on instantaneous conditions to determine a quasi-steady predicted cabin noise time-history. These techniques demonstrated that the cabin noise response to oncoming flow unsteadiness remained generally quasi-steady up to fluctuation frequencies of approximately 2 to 5 Hz, where above this smaller flow scales have a progressively smaller impact on cabin noise fluctuations. Therefore, with a measurement of both the cabin noise in the steady environment of the wind tunnel and the unsteady onset flow conditions, the fluctuations (and thus the modulation) of the wind noise under these unsteady conditions is able to be predicted. |
Investigation of Squeak and Rattle Problems in Vehicle Components by Using Simulation & Doe Techniques | The automotive and related industries are concentrating their efforts on improving comfort by lowering engine, wind, and road noise and vibrations. However, as background noise levels decrease, the squeaks and rattles (S & R) generated by the vehicle's many components become more noticeable and distracting. As a result of the absence of a dominant noise source from a traditional petrol/diesel car, (S & R) noise becomes more dominant than other types of noise in electric vehicles. In this paper, we propose a novel simulation technique for developing a systematic approach to identifying and solving (S & R) problems in vehicle components/sub-assemblies during the primary stage of product development cycle, thus reducing the overall product development time. This paper will present a novel approach to comprehending various methods and Design of Experiments (DOE) techniques used to determine the root cause of (S&R) problems and to solve those using numerical methods. |
Axiomatic Design of the Check Link for an Automotive Side Closure System | In the automotive industry, a lot of attention has been paid to the effort required for opening/closing the doors, and for a good reason. The door closing and opening effort creates an impression in the customer’s mind about the engineering and quality of the vehicle even before he or she enters it. Although this seems trivial compared to the complexity of the rest of the automobile, effective engineering of the door opening/closing effort is challenging due to the interaction of several design parameters. Some of the best practices focus on satisfying targets for the energy required shutting the door from a small open position (around 10 degrees). However this practice ignores the complete closing/opening motion of the door from a full open position. In this paper Axiomatic Design principles were used to obtain a better understanding of the door opening/closing motion from a full open position, in terms of the functional requirements (FR), and how these requirements are satisfied by the various design parameters (DP) of the door closure system. In this paper we present an analysis of the opening/closing efforts of the side door closure system using this Axiomatic Design approach, and a discussion on the design of the check-link. The complete opening/closing motion is a result of the interaction of the different components of the door closing system, such as the latch, weather seal, energy loss due to air-binding effect, the inclination of the hinge axes, and the check-link. FR/DP decomposition of the Door System is presented. This provides the framework for creative design solutions. |
Development and Validation of Utility Matrix for Automotive Interiors in Real World Usage | As the real world usage profile of customers is becoming increasingly dynamic the need for more utility features in interior parts of vehicle has increased. The main purpose of the study is to analyze how the changing customer style actually influences the volume requirement of the utility spaces i.e. at the glove box, console door pocket etc. In the present study, an exhaustive list of utilities, and a utility matrix based on the user characteristics for automotive interiors is developed. Based on customer reviews on the web and expert opinions, seven user profiles were defined. The selection matrix is arrived at by using the usability index, accessibility index and the disbursement index. The matrix is evaluated using statistical methods and validated for real world usage. The selection matrix is used to identify relatively important utility features and preferred locations in automotive interior parts. |
Secondary Control Modifications | This SAE Recommended Practice establishes a uniform procedure for assuring the manufactured quality, installed utility and performance of automotive products to the relocation, alteration, replacement and/or extension of secondary controls and systems other than those provided by the vehicle manufacturer (OEM). These products are intended to provide driving capability to persons with physical disabilities. These products function as adaptive modifications to compensate for lost or reduced function in the extremities of the driver. These include, but are not limited to the following: Cruise Control; Door Locks; Gear Selector; Hazard Flasher; Headlight Beam Selector; Heater/Vent/Air Conditioner (HVAC); Horn; Ignition/Starter; Light controls; Mirrors; Parking Brake; Power Seats; Turn Signals; Power Window Controls; and Windshield Wiper/Washer and defogger; Rear Accessories (Defogger, Wiper/Washer). The purpose of any secondary control adaptation is to provide the effective use of the motor vehicle operating systems to a driver with a disability, so that he or she may drive and operate that motor vehicle with the same degree of safety as a non-disabled driver. Thus, the adaptive equipment must be (1) accessible to the driver with a disability for whom it is designed, (2) not susceptible to inadvertent operation which may be inconvenient or dangerous for the driver and other users of the roadway, and (3) suitable by non-disabled drivers who may have a need to operate the motor vehicle whenever possible. For purpose of this document, the secondary controls listed previously have been classified according to the following protocols. The categorization of these controls, while different from other SAE publications, is reflective of the manner in which driver rehabilitation specialists determine appropriate vehicle modifications. These categories are arranged to assign priorities that allow the user to operate a vehicle in the most efficient manner possible. Mode A - These controls shall be operable by the driver while the vehicle is in operating mode. They must be accessible to the driver for which they were intended while being able to maintain control of the vehicle steering, brake and accelerator functions. Included in this group are: Cruise control “Set;” Headlight Beam Selector; Horn; Turn Signals; and, Windshield Washer/Momentary Wipe. Mode B - These controls shall be operable by the driver while maintaining control of the vehicle brake function with the vehicle not in motion, as in the case of vehicle start-up or re-start necessitated by engine stall. Included in this group are: Gear Selector and Ignition/Starter. Mode C - These controls shall be at least operable by the driver when the vehicle is stationary, either temporarily or parked. Included in this group are: Cruise control “On” and “Off;” Door Locks; Hazard Flashers; Heater/Vent/Air Conditioner (HVAC); Light Controls; Mirrors; Parking Brake; Power Seats; Windshield Wiper; and Power Window Controls; Rear Accessories (Defogger, Wiper/Washer). |
A Study on the Methodology for Improving IQS Score for Door Opening/Closing Effort | IQS score (hard to open/close) is a major factor in determining automotive door closing performance. There are several functions that automotive side doors must fulfill: isolation from snow/ rain/ noise/ dust/ high temperature, wind noise, and opening/closing functions. This paper focuses on side door Opening/Closing, which is not only the primary function but also the first operation that all customers experience when car shopping. As the subjective demands of customers have increased and their level of sophistication has grown, the ergonomics of automotive side door functions has become a critical issue for both designer and customer. The side door area does not generally have specifications because door operability totally relies on each customer's senses and there are no parameters to be measured by test/experimental devices. So the IQS score could become the standard for evaluating a door's difficulty of opening and closing. The objective of this work is 1)to develop a correlation between subjective evaluation, some test results and IQS score (hard to open/close) and 2)to find ways to improve IQS score (hard to open/close) by reducing the minimum closing velocity. |
Study of Minimum Door Closing Speed Analysis Method | The minimum door closing speed is an important target in vehicle door design. Engineers need a proper method to evaluate the door closing speed during the design phase. Analytical approaches are presented to solve the difficult issues in analyzing the minimum door closing speed. First, the weather strip is simplified into a discrete model with several spring elements. This method does not need to use 3-D contact analysis for the weather strip and can save computing time with acceptable accuracy. Second, the minimum closing speed is solved by using the energy equation which needs one iteration only. The method has high efficiency and can be used to evaluate the door closing speed effectively during the design phase. |
Door Check Load Durability - Fatigue Life Prediction | This paper describes an analytical methodology for predicting the fatigue life of a door system for check load durability cycles. A check stop load durability cycle occurs when a customer opens the door beyond the door detent position with a force applied on the check link or hinge check stops. This method combines Finite Element Analysis (FEA) model and fatigue code to compute the durability requirements. The FEA model consists of Door-in-White (DIW) on body with integrated hinge check link or independent check link. Nonlinear material, geometric and parts contact were considered for the door with body-in-white (BIW). Several door hinge designs, with integrated and independent check links, were investigated. Using the Von Mises stress and plastic strain from the above analysis, the fatigue life was predicted and compared with the test data. Integrating FEA and fatigue allows predicting the threshold total strain value, which is developed, for check load durability requirements. The strain-life plots were developed for both car and track programs to be used at the early design stage to estimate the fatigue life of the structure. Various material hardening models were evaluated. The strain hardened-isotropic hardening and cyclic-combined hardening were compared. This method improves design cycle time and reduces the warranty by producing a product design that comprehends the fatigue damage resultant from the application of check stop load to the door structure. |
Direct Sensor Solutions for Anti Pinch and Collision Avoidance for Motorized Closures | Motorized closures support the comfort in vehicles to an increasing degree. In the past the use of indirect sensors was an effective low-cost solution for anti pinch [1,2]. The demand for a reduction of the forces affecting the user and for minimized closing times leads to direct sensor solutions. A new aspect is the protection of moving vehicle parts, which we call collision avoidance. This paper deals with system aspects securing the movement area of motorized closures. An analysis is made for sliding doors, trunk lids and tailgates, pointing out the danger zones and the use cases. The result of a QFD (Qualitiy Function Deployment) with respect to the demands of the customer is shown. This leads to a rough description of the requirements for the technical solutions. A technology benchmark is conducted separately for anti-pinch and for collision avoidance. The two applications have distinct requirements; therefore different technological solutions are identified. As an example, the tailgate is examined in detail and a solution for securing the danger zones is presented. A Lab car is equipped and tested. For anti-pinch, a capacitive sensor system is selected and designed. Collision avoidance is realized by adopting a series automotive ultra-sonic sensor. Environmental influences are examined and described. Special integration problems and their solutions for both sensor systems are discussed. The topology of the electronic components is described and an outlook on the future is given. |
Comparing the Harness Cost of Hardwired and Networked Integrated Door Systems | The objective of the research discussed in this paper is to propose a methodology for comparing candidate electrical architectures on a cost basis at the very beginning of the architecture design process. To achieve this objective, historical data concerning the cost of a wiring harness for a driver’s door electrical system is analysed along with information on an electrical architecture for the door system of a small four door passenger car. The study is focused around a driver’s door electrical system based on LIN and hardwired integration. However, it is concluded that the results are applicable to other types of automotive electrical architectures. |
Evaluation of Door Latch Response to Vertical Loading Conditions | Field research has consistently demonstrated that the risk of occupant death or serious injury in motor vehicle crashes is significantly reduced when occupants are retained within the vehicle.[1][2] The injury prevention benefits of passenger vehicle door systems require that they remain closed during collisions. Federal Motor Vehicle Safety Standards (FMVSS) and SAE Recommended Practices set forth door latch performance requirements to “minimize the likelihood of occupants being thrown from the vehicle as a result of impact”. Currently, there is not a vertical latch strength requirement for hinged side doors in FMVSS 206. A recent study has raised concerns about latch performance in response to vertical loading conditions. In order to investigate door latch performance in response to vertical loading conditions, the latch must be evaluated using techniques more representative of loading conditions in real world accidents. This study investigates side door latch performance in full vehicle and door system component testing as opposed to the component-only fixture testing outlined in FMVSS 206. Both full vehicle and door system testing showed that the tested side door latches managed forces that were substantially higher than any loads required by FMVSS 206 when subjected to purely vertical loading. |
A case-study about side door closing effort | Door Closing Effort is one of the first impressions a potential customer has about a vehicle. The energy someone needs to give out to push and lock a side door vehicle is easily felt and can enhance the impression of a robust and high quality design vehicle. In other words, Door Closing Effort is one of the issues manufacturers shall look over in order to achieve perfect levels of Human Vehicle Integration (HVI). The aim of this paper is to present a case study of Side Door Closing Effort of a specific Hummer vehicle. It will be shown how door closing effort varies according to several parameters, and how to improve the design and/or production process in view of achieving better effort levels, considering the Hummer case as a background. Several variables that influence on the overall energy of this process have been evaluated, and the physical differences were weighted to demonstrate what really counts for reaching a comfortable level of Door Closing Effort. |
Guidelines for vehicle development based on principles of universal design | In order to fulfill the users' needs, many innovations are included in vehicles. However, not all of these vehicles can be used by People with Special Needs (PSN), due to their technical characteristics and/or adaptation cost, even with the financial incentives offered by Brazilian Government. In this context, the Universal Design (UD) is inserted, where PSN and people without physical deficiencies can use the same vehicle, with little or no adaptation. In order to identify the needs of PSN, interviews were carried out with PSN and exhibiters of automotive products for PSN, in the VII Reatech 2008 (International Fair of Technologies of Rehabilitation, Inclusion and Accessibility), where can be highlighted: to lower the car floor; to improve the door access (increasing width, height and opening angle); to improve the internal space of vehicles; to reduce the cost of adaptation kits; and others. Inclusion programs of the main Brazilian automotive manufacturers were also identified, focusing on kits for automotive adaptation, where some of them were preliminarily evaluated. Finally, general guidelines for vehicle development are proposed, based on principles of UD, results of interviews and a literature review. |
Bake Hardening Steel (BH220) Characterization | The bake hardening effect depends on three parameters i.e. pre-straining, paint baking temperature and paint baking time. The combined effect of all these parameters results into the increase in yield strength, called the “baking effect”. This paper explains the individual effects of these parameters on the baking value. Tensile test were carried out for the 495 samples baked at baking temperature from 140°C to 250°C with differential baking time of 10, 15, 20, 25 and 30 minutes and differential pre-straining of 2%, 3% and 5%. The differences of yield strength between the unbaked and baked sample were calculated and the increase in yield strength was noted. After these laboratory trials 800 numbers of door outer panels of a small truck were formed and finish painted. The increment in yield strength after component forming and painting was determined by taking tensile samples from three different locations of 5 painted doors. This would help shop floor optimization of the process parameters and the compatibility with various painting process vis a vis increase in bake hardening strength. It is also leading to a future work to understand clearly the correlation between the baking temperature, increase in strength and the micro structural changes. |
Recycling Long Glass Fiber Reinforced Polypropylene Instrument Panel Trim Offal | Production of soft, padded instrument panels (IP's) with a Long Fiber Reinforced Polypropylene (LFPP) substrate have areas for HVAC outlets, air bag doors, IP clusters and glove box doors that are molded over with substrate/ urethane foam/ skin. These openings are subsequently die punched out. These areas are molded over to prevent foam bleed to the backside of the IP during the production foaming process. Typically they are 12% of the total material usage. The punched sections of composite substrate/foam/skin (punch outs) have traditionally gone to landfill, typically at a cost of $0.05/lb. to the Tier 1 supplier. Wipag Recycling in Germany has developed a process whereby the substrate material is recovered from the composite structure, separating the resin from the foam and skin. The resin has 99.8% purity and can be subsequently blended back into virgin resin for production at a specified percentage without statistically varying the physical properties of the LFPP IP substrate. The WIPAG laminate separation process has been in commercial operation at American Commodities Inc. (ACI) in Flint, MI for the past 7 years albeit with SMA, PC/ABS and TPO substrates. With regard to recycling LFPP, traditional wisdom dictates that the material properties of the resin will be reduced after each heat history due to glass fiber length attrition, caused from the processing of the material. This study shows that up to 30% of resin reclaimed from the composite substrate can be added to virgin material with a minimal effect on the properties of the final part. |
Applicability of Different Loudness Models to Time-Varying Sound in Vehicle | Three sound loudness calculation models, including Zwicker instantaneous loudness model, Moore instantaneous loudness model and Moore time-varying loudness model, and the cited Zwicker time-varying loudness model in ArtemiS, were applied to calculate the time-varying loudness of three typical vehicle sounds, in particular. They are steady engine idle noise, impulsive door closing noise and order-swept electric vehicle pass-by noise. Based on the loudness amplitude and time-frequency loudness results, the applicability of the four loudness models to time-varying sounds was analyzed and compared. It was found that, both Zwicker and Moore time-varying loudness models are more reliable than Zwicker and Moore instantaneous loudness models if the sound amplitude and frequency vary tempestuously. And the time-frequency result of Moore instantaneous loudness model can be very helpful to noise source identification and mechanism analysis. |
Invisible PAB Door Development Using Two-shot Molding | Invisible Passenger-side Airbag (IPAB) door system must be designed with a weakened area such that the airbag will break through the Instrument Panel (IP) in the intended manner, with no flying debris at any temperature. At the same time, there must be no cracking or sharp edges at the head impact test (ECE 21.01). Needless to say, Head impact test must keep pace with the deployment test. In this paper, we suggested soft airbag door system that is integrally molded with a hard instrument panel by using Two-shot molding. First of all, we set up the design parameters of IPAB door for the optimal deployment and head impact performance by CAE analysis. And then we optimized the open-close time at each gate of the mold so that the soft and hard material could be integrally molded with the intended boundary. We could make the boundary of two materials more constant by controlling the open-close time of each gate with resin temperature sensor. |
A Study on the Optimization of Body Structure for Rattle Noise by Exciting Woofer Speakers | With the recent development of technologies for interpreting vibration and noise of vehicles, it has become possible for carmakers to reduce idle vibration and driving noise in the phase of preceding development. Thus, the issue of noise generation is drawing keen attention from production of prototype car through mass-production development. J. D. Power has surveyed the levels of customer satisfaction with all vehicles sold in the U.S. market and released the Initial Quality Study (IQS) index. As a growing number of emotional quality-related items are added to the IQS evaluation index, it is necessary to secure a sufficiently high quality level of low-frequency speaker sound against rattle noise. It is required to make a preceding review on the package tray panel, which is located at the bottom of the rear glass where the woofer speakers of a passenger sedan are installed, the door module panel in which the door speakers are built. Based on the theoretical background of robust design, this study seeks to suggest design criteria that are insensitive to the noise factors of the package tray panel. |
Real-time Simulation of a Vehicle Door Locking Mechanism on a Hardware-in-the-Loop Platform | An automotive side door latch release mechanism has been modelled for the locking and unlocking vehicle functionality in Dymola. The performance of the developed door lock model is evaluated against an existing model of a similar door locking/unlocking system in Stateflow. The model performance is also compared with measurements from a real vehicle door latch. The model is converted into a Simulink model and built for a real-time environment such as the dSPACE target with a fixed step size solver. It is shown that a step size as small as 1 ms can be used for real-time simulation without task overrunning in the real-time target. The model is also benchmarked on a multiprocessor setup as multiprocessor simulators are common in system-level networked Electronic Controller Unit (ECU) testing facilities for implementing high fidelity closed loop models of integrated ECUs and actuators. It is proven that the developed door lock model in Dymola can be built and executed on a multiprocessor platform and there is much potential on the use of such models for future work in ECU testing. |
Capitalizing on the Increased Flexibility that Comes from High Power Density Electrothermal Deicing | This paper introduces a recent development in electrothermal heating technology that enables increased power densities on the leading edge of aircraft wings for the purpose of de-icing. Key aspects of this development include a high temperature heater mat, minimal thermal interference between the heating element and leading edge skin, a high quality bond of the heater to the skin and a power density profile that compensates for non-uniform thermal loads on the leading edge skin. Icing tunnel testing results corroborate the value of these key aspects in enabling operation at extreme power densities, even to the point of achieving full evaporative anti-icing operation under Intermittent Maximum conditions. The advent of higher power density capabilities has opened the door to new approaches to electrothermal deicing that were previously impracticable. Some of these new approaches and their benefits are presented. |
Vehicle Roof Strength Test Procedure | This SAE Recommended Practice establishes a uniform laboratory test method to evaluate the strength characteristics of roof systems. The test procedure is intended to provide reliable and repeatable results and to permit numerical comparisons. A test is conducted in which the vehicle roof system is loaded under controlled laboratory conditions. Structural strength measurements are obtained under load application angles chosen to concentrate forces on the forward portions of the roof panel and roof supporting structure. |
Passenger Car Door System Crush Test Procedure | This SAE Recommended Practice establishes a uniform laboratory test method to evaluate the capability of passenger car door systems to resist a concentrated lateral inward load. The procedure is intended to provide repeatable results and to permit numerical comparisons. A test is conducted in which the door and related structural members of the vehicle are loaded under controlled laboratory conditions. Structural strength measurements obtained under these conditions are reproducible. Background information and rationale for the test procedures described in this Recommended Practice are provided in the Appendix. |
Door-Closing Sound Quality Improvement Process Based on Beamforming Method, Wavelet Analysis, and Component Design Optimization | Door-closing sound quality is a very important noise, vibration, and harshness (NVH) attribute since it may have a significant impact on customers’ perception, recognition, and luxury sensation of an automobile brand. Therefore, its evaluation methodology and design process have been one of the research and engineering efforts for all NVH organizations in the automotive industry. In many cases, the resolution of a door-closing sound quality issue lacks a systematic approach, and engineers rush to work when an issue surfaces. While subjective evaluation may easily find a door-closing sound problem, it oftentimes cannot directly pinpoint and go right to the root cause of the issues, and engineers could only guesstimate the possible relevant structural components based on past experiences. In this work, a door-closing sound quality development process, which has already been implemented in vehicle programs, is summarized and presented. The process involves a systematic workflow in a relatively short turnaround time. It begins with the beamforming method to carry out the sound source localization to facilitate the accurate determination of the key areas that impact the door-closing sound quality and then followed by objective measurements to acquire the sound data for the examination of the temporal behavior and spectral content processed by the wavelet analysis. After a better understanding of the key components along with the sound characteristics obtained, the effort is then focused on the investigation of the component mechanisms and optimization of the relevant hardware kinematics. A case study based on a high-end passenger vehicle is presented, and in this particular example, it is found that the door latch design and weather strip on the upper window frame are the critical components. Once the design proposal is implemented, the door-closing sound quality has finally met the program target. |
An Overview of Automotive Wind Noise and Buffeting Active Control | As the wind speed increases, the contribution of wind noise gradually exceeds other noise sources, affecting comfort. First, the classification of automotive wind noise is discussed in detail according to the formation mechanism, sound analogy, and pressure type. Then the wind noise evaluation and development tools are summarized. Finally, the characteristics and control means of vehicle window-induced buffeting noise are discussed. Considering the appearance and field of view, it is currently difficult to control side window buffeting based on passive methods. Therefore, the proposed method of actively controlling the window opening size, actively opening multiple windows, and even releasing an inverse phase sound source based on control logic has a good application prospect. |
Wind Noise Contribution Analysis | This article is motivated by observations of the wind tunnel measurement data acquired during benchmarking and program development for a variety of passenger vehicles over the years. In wind noise development, contribution analysis is a common practice to screen and identify the most significant sources and paths. In order to shed light on the whole picture of the contribution analysis, the work presented in this article falls into two categories. One is the analysis of underlying mechanisms for a better understanding of the phenomena observed in the contribution results. The other is the summarization of wind noise contributions obtained by wind tunnel testing for some representative subsystems, e.g., the contributions based on different reference states, the effect of grilles, underbody, acoustic glass, and auditory masking. A close look at the obtained numbers for each vehicle reveals that all these numbers have their intrinsic characteristics, and the same number may not tell the same story. The components with the same design, cost, and quality behave differently in vehicles with different wind noise levels. This work shows that contributions are generally reference-based and vehicle-dependent, and vary when the reference state is deviated even for the same vehicle. The same subsystem contributes more to a quiet vehicle than a mediocre vehicle, thereby a direct comparison of contributions among different vehicles is unfair and biased against quieter vehicles. As a first approximation, a quantitative estimation is derived to promote a qualitative understanding. It is used to facilitate a fair comparison of contributions, which are based on different reference states from either the same vehicle or different vehicles. It also implies that a vehicle with superior wind noise performance carries with it a much more stringent standard in subsystem design than an average vehicle even though their contribution targets are similar. The understanding of the work presented in this article would further benefit the interpretation of various contribution results, their comparison, and subsystem target setting. |
Finite Element Model Reduction Applied to Nonlinear Impact Simulation for Squeak and Rattle Prediction | Increasing demand for simulation accuracy often leads to increased finite element model complexity, which in turn, results in higher computational costs. As a provision, component mode synthesis approaches are employed to approximate the system response by using dynamic substructuring and model reduction techniques in linear systems. However, the use of available model reduction techniques in nonlinear problems containing the contact type of nonlinearities remains an interesting topic. In this paper, the application of a component mode synthesis method in squeak and rattle nonlinear simulation has been investigated. Critical regions for squeak and rattle of the side door model of a passenger car were modelled by nonlinear contact definition in finite element simulation. Craig-Bampton model reduction method was employed to substructure the finite element model while keeping the nonlinear contacts in the model. The model response was evaluated using the modal assurance criterion, frequency response analysis and contact force magnitude in comparison with the baseline model. Results showed that a great reduction in computational time (about 98%) can be achieved while the accuracy of the system response was maintained at an acceptable range for the intended application for squeak and rattle simulation. Although the prediction of impact events in time was done accurately, the contact force magnitude was estimated with average error of 2.5% to 22%, compared with the baseline results. The outcomes of the study show that to empower squeak and rattle prediction by including contact interfaces in finite element simulations, implementation of the model reduction approach can compensate the simulation cost. |
Passenger Car Door Closing Effort Prediction Using Virtual Simulation and Validation | In the automobile industry, the door closing effort spells out the engineering and quality of the vehicle. After the visual impact a vehicle has on the customer, the doors are most likely the very first part of the vehicle he/she encounters, to enter and exit the vehicle. One of the customer’s very first impressions about the quality of the car is given by the behavior of the doors when opening and closing, the swinging velocity and the energy that is required to obtain a full latching that the door makes when closed by the user. Door closing effort gives an indication of how good or bad the vehicle is engineered. The purpose of this paper is to propose modifications in the door system which help in reduction of door closing effort or velocity by two different methods, EZ Slam Door and Bungee Rope. In this paper, parameters like hinge friction, hinge axis inclination, sealing, latch and air bind effect are analyzed which affect door closing effort. A virtual model is prepared in MSC.ADAMS to evaluate door closing velocity through calculating energy contribution by each parameter. Door closing effort or velocity is calculated for the existing model and to improve the existing scenario, design modifications are proposed. These design modifications after implementation have shown 20% reduction in door closing effort or velocity. Physical validation was done, and results were found in line with the virtual simulation. The correct method for door closing effort prediction is proposed based on real world customer usage pattern. |
Deep Generative Design Models for Improved Door Frame Performance | Significance of CAE simulation thus is increasing because of its ability to predict the failure faster, also lot of design combinations can be evaluated with this before physical testing. Frame stiffness of side doors is one of the major criteria of a vehicle closure system. In most cases, designers around the globe will be designing same or very similar side door frame structures recurrently. In addition, in the current growing trend having an optimized side door frame design in quick time is very challenging. In this investigation, a new artificial intelligence (AI) approach was demonstrated to design and optimize frame reinforcement based on machine learning, which has been successful in many fields owing to its ability to process big data, can be used in structural design and optimization. This deep learning-based model is able to achieve accurate predictions of nonlinear structure-parameters relationships using deep neural networks. The optimized designs with optimization objectives as deflection is obtained efficiently and precisely using Bayesian Optimization algorithm. Deep learned computational results were validated by the experimental results. Furthermore, the developed deep neural networks show how various design sections of door frame structures behave and how it can be used as a reference for future door design through deep generative model techniques. Keywords: Door Frame Reinforcement, Deflection, Deep neural networks, Bayesian Optimization algorithm |
1D Modeling of HVAC Unit Air Flow for Automatic Climate Control Simulations | Advanced control techniques are widely used in different automotive applications including climate control. Significant costs associated with the development and calibration of such controllers can be reduced if these tasks are conducted in a virtual environment. Such a virtual environment can be developed by integrating the controller with the system model. Different scenarios can be then simulated to make sure functional objectives of the system are met. 1D models provide the necessary level of accuracy without imposing extra computational cost in such virtual environments. As such, they are perfect candidates for model, hardware or software-in-the loop validation benches for controls. Performance of a heating, ventilation and air-conditioning (HVAC) system can be controlled through the settings of the components like mode door, blend door, recirculation door, blower, and the compressor. In an automatic climate control (ACC) system, these factors are automatically actuated to achieve thermal comfort. For development and calibration of ACC systems, virtual setups with a model of HVAC unit can be used. In this case, the model should capture the flow inside the HVAC unit which could be impacted by the door positions. This paper proposes a 1D model for HVAC unit air flow, where components such as mode door, blend door, recirculation door, and blower are modeled and calibrated. Capability of the model to predict temperature values along the unit is then validated against test data. The promising results demonstrate the model potential in ACC virtual development and calibration. This can reduce the number of tests needed and help minimize the cost, effort, and possible delays in product development. |
Analysis of Discretization for Transient Impact Loads on Door Closing | The transient impact load generated by door closing is used as the input of the closing condition, which is an important part of door system investigation. In this article, the basic theory of transfer path analysis (TPA) is introduced to handle the abnormal vibration of the front-left door with the glass down stall position of a certain vehicle during the closure. The transient impact loads are discretized under the closed door and obtained using the inverse matrix (IM) method in TPA. Vehicle test and bench test are conducted. The closed door is subjected to the transient impact loads of the sealing strip and the latch on the body side. In the vehicle test, acceleration sensors are pasted on the target point and the reference point on the door to obtain the acceleration vibration response upon the door closure. In the bench test, when the hammer strikes the excitation points, the frequency response functions (FRFs) from these points to the reference point and to the target point are recorded by the acceleration sensors. The vibration amplitude of the front-left door with the glass down stall position is taken as the criterion. Finally, a reasonable discretization number of the door-closing transient impact loads is determined, which provides guidance for subsequent research of the door system. |