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Evaluation of the severity of low speed motor vehicle crashes has been the subject of significant research for more than 25 years. These crashes typically result in little if any damage to the vehicles involved and therefore the ability to determine the threshold of damage would be very useful in analysis of such cases. One such threshold, which has been used by accident reconstructionists, is the manufacturer’s published bumper rating in compliance with Federal Motor Vehicle Safety Standards (FMVSS) for vehicle bumpers. The rationale is that if there is any damage to the bumper system of the vehicle in question, the impact must have had a severity greater than the rated bumper speed. This paper examines the FMVSS bumper standards upon which the published bumper ratings are reportedly in compliance, historical low speed testing damage results, and engineering considerations of bumper damage in low speed impacts.

This paper examines one of the approaches used to identify the root causes of sound quality issues in vehicles, including the direct impact of psychoacoustics on the human experience. Specifically, the absence of masking effects provided by traditional combustion engines has made noise and vibration from electric drives significant factors in decision-making processes, with high-pitched tonal noise from electric motors causing annoyance and sound quality concerns for electrified propulsion systems. During vehicle testing at different speeds, a whining noise was observed, leading to an NVH test to locate the noise source. The noise is traced to the transmission by the dominating order of input reduction along with the contribution from the casing resonance. A multi-physics-based e-NVH analysis was performed, and the test data were correlated.

The dimensions of automobile-body seats receive consideration with regard to the features that are conducive to comfort. A diagram is presented upon which the dimensions treated are indicated, and a tabulation of seat dimensions of 12 representative cars is included. Comments are made upon the factors influencing seat dimensions, as well as recommendations regarding the different desirable dimensions. The considerations are inclusive of cushion height, depth and slope, leg-room and head-room, upholstery shape and softness of trimming, foot-rest and other control-element locations, factors influencing entrance and egress provisions, seat widths and advisable front and rear-compartment heights. The author recommends the standardization of a range of locations for the different control elements.

Customers expect more advanced features and comfort in electric vehicles. It is challenging for NVH engineers to reduce the vibration levels to a great extent in the vehicle without adding cost and weight. This paper focuses on reducing the tactile vibration in electric vehicle when AC is switched ON. Vibration levels were not acceptable and modulating in nature on the test vehicle. Electric compressor is used for cabin cooling and battery cooling in the vehicle. Compressor is connected to body with the help of isolators. Depending upon cooling load, the compressor operates between 1000 rpm and 8000 rpm. The 1st order vibration of compressor was dominant on tactile locations at all the compressor speeds. Vibration levels on steering wheel were improved by 10 dB on reducing the dynamic stiffness of isolators. To reduce the transfer of compressor vibration further, isolators are provided on HVAC line connection on body and mufflers are provided in suction and discharge line.

This study investigates the relationship between the gross weight and net engine horsepower of commercial vehicles. The data were used to update current information on weight-power ratios of trucks and investigate the trend in the ratios since 1949. There is a definite increase in the weight-power ratio as the number of axles increases, regardless of vehicle type. There is also an overall trend to lower weight-power ratios as evidenced by a 12% reduction in the ratio from 1949 to 1955 and a further reduction of 28% from 1955 to 1963. A performance requirement of 400 lb/hp is liberal and would affect only a small percentage of the total trucks.

Ten commonly found statements and beliefs regarding threaded fasteners are examined against appropriate data. They are all false and misleading. The author presents them in an order and manner which should lead to an understanding of what makes bolted joints work or fail. From “vibration” loosening to “lock” washers the facts associated with the fables are presented as assisting in the achievement of fastener objectives: 1) Development of predictable clamp load 2) Prevention of self loosening 3) Maintenance of the ability to disassemble the joint by avoiding corrosion and galling.

Tests have been performed to investigate how the average deceleration experienced by a motorcycle sliding to rest on its side from high speed compares with the friction measured in a low-speed drag test. This has been done both by launching motorcycles from a low platform, and by allowing them to fall to their sides from an upright position, from speeds between 32 and 90 km/h. It was found that the friction measured in the low-speed drag tests gave a value close to the high-speed sliding value. The friction was affected by the road surface texture, the presence of prominent side projections, and the wearing away of these projections during the slide. Some speed dependence was noted in the upright-launch tests which appears to be due to the “digging-in” of the machine as it falls to the road, rather than an effect of the sliding friction itself.

This paper concerns the control of compliance steer for the rigid axle rear suspension of large-sized buses. The distortion of rear axle alignment (Compliance Steer) by the disturbances from the road surface is one of the biggest elements which disturb the running straightness of large-sized vehicles. By redesigning the compliance steer characteristics to generate counter axle steer when disturbances are applied, the stability of running straightness will be improved.

Motorcycle collisions by their very nature are difficult at best to analyze and/or reconstruct. Motorcycles come in as many different types, models and styles as do passenger vehicles and trucks. The inherent problems of load changes and articulation are enough to discourage anyone from reconstructing these type of collisions. This document is a result of efforts by members of the Washington State Patrol Traffic Investigation Division and members of the Washington State Patrol Academy. The purpose of the tests was to use the G-Analyst to determine the most appropriate value for both rear and front brake resistance during brake application and to make some comparisons of acceleration rates and deceleration rates.

Knowing motorcycle speeds at various points throughout an accident sequence is valuable in reconstructing an accident. Often, the motorcycle slides on its side for some distance during the accident sequence. In order to account for the sliding segment in the speed calculations, a suitable slide coefficient must be selected or determined. During this study, an accurate measurement methodology was developed for determining slide coefficients. Once the test methodology was established, eight different motorcycles were tested to determine their slide coefficients at 48 and 97 km/h. The test surfaces were asphalt pavement, dirt, and gravel, and the motorcycles were tested on the right and left sides. Some motorcycles were tested multiple times on one side also. The test group included standard, cruiser, sport, and touring motorcycles.

This paper discusses the problems inherent in the braking of motorcycles and other powered two-wheeled vehicles and suggests ways in which antilock brake systems and other engineering measures can assist riders. Evidence is presented of the failure of many motorcyclists to brake effectively, and it is suggested that advances in engineering will lead eventually to an improvement in braking behaviour. Results obtained by the antilock system installed in ESM-2 are compared with those obtained by a variety of riders.

This paper shows that the functional integration of Electronic Throttle Control (ETC) into the engine control strategy allows improvements of emissions and fuel economy without making compromises in respect of driveability. A cost effective way for realizing ETC is the integration of the control electronics into the engine control unit (ECU). The paper describes the consequences of such an integration for the ECU hardware and software. Special attention is given to the ETC related safety aspects. Another chapter discusses different technologies for the throttle actuator drive. This is followed by a brief description of a suitable control strategy for a throttle actuator. Finally the paper gives also an overview about current status and development trends of accelerator pedal sensors necessary for ETC.

From our crash investigations of air bag equipped passenger cars, a subset of upper extremity injuries are presented that are related to air bag deployments. Minor hand, wrist or forearm injuries-contusions, abrasions, and sprains are not uncommonly reported. Infrequently, hand fractures have been sustained and, in isolated cases, fractures of the forearm bones or of the thumb and/or adjacent hand. The close proximity of the forearm or hand to the air bag module door is related to most of the fractures identified. Steering wheel air bag deployments can fling the hand-forearm into the instrument panel, rearview mirror or windshield as indicated by contact scuffs or tissue debris or the star burst (spider web) pattern of windshield breakage in front of the steering wheel.

Field data was analyzed on second-row children in front, side and rear impacts to study fatality trends by model year (MY) and calendar year (CY) with 1980-2020 MY vehicles. The different MY and CY perspectives show changes in rates that are useful for setting priorities for second-row child safety in rear impacts. 1990 to 2019 FARS was queried to assess the number of fatally injured and non-ejected second-row children (0-15 years old) in crashes without fires. The children included outboard occupants seated behind an occupied front seat and center occupants. The data was analyzed for rear, front and side impacts to assess crash frequency. 1990-2015 POLK was queried to assess exposure of registered vehicles and estimate a fatality rate. The FARS and POLK data were sub-grouped by MY of the vehicle and CY of the crash. There were 2.8-times more fatally injured children in frontal crashes than in the rear crashes. The ratio of frontal and rear crashes varied with CY sub-groups.

Fatigue simulation is an essential part of the development of components and systems in the automotive and machinery industry. Weak points can be identified fast and reliable. A pure virtual optimization of the design can be performed without the need of prototypes. Only for the production release a final test is necessary. A lot of parameters influence the fatigue life as the local stress, material, surface roughness, temperature etc. Notches have the strongest impact on fatigue life since they cause an increase of the local stress. Also, the local fatigue strength is increased in notches because of a support effect from the neighboring areas. To account for this effect, several methods exist, each with their specific advantages and disadvantages. In this contribution an overview is given with brief descriptions for some common methods. The methods are compared both from a theoretical and practical point of view.

Electronic control units of Bendix® ABS/ESC and Collision Mitigation Systems have the capability to record event data in the ABS/ESC control unit. Bendix refers to this event data recording functionality as the Bendix Data Recorder (BDR). This paper presents an overview of the BDR functionality and examines the range and resolution of data elements, the synchronicity or timing of the recorded data, and application of the data for use in analyzing crashes. Various tests were performed using trucks equipped with Bendix® Wingman® Fusion™ and were conducted in a manner to trigger BDR records. BDR data was compared to data collected from the J1939 CAN Bus and from Racelogic VBOX data loggers.

High cycle fatigue (HCF) S-N curves of steels are applied by OEMs for direct evaluation of the products' durability or as an input to their CAE for design purpose. It has been found that the existing models for S-N data resulting HCF test might have difficulties in properly depicting the entire spectrum of fatigue lives. To overcome these difficulties, a new equation has been developed based on the relationship between the behaviors of short and long fatigue lives. The new equation was applied to model S-N data resulting from recent HCF testing of several steels and was compared with the 3 existing popular models. The comparison in the preliminary validations indicated that the new equation has high potential for application in more accurate S-N data modeling and fatigue limit prediction.

This research focuses on the use of Event Data Recorders (EDR) to assist in calculating speed loss or ΔV undergone by a motorcycle in a broadside type impact into a vehicle. If the struck vehicle has EDR data, this could be a useful tool in calculating motorcycle ΔV or corroborating motorcycle ΔV calculations from crush or other methodologies. Certain parameters critical to calculation of motorcycle ΔV must be considered, including the appropriate effective mass to use for the motorcycle/rider combination. This study used crash test data to determine a method of applying parameter values to accurately calculate motorcycle ΔV in a motorcycle-vehicle collision. In this study, three crash tests were performed in which a motorcycle with a dummy rider traveling in the range of 42 to 51 mph collided into the right front corner of a vehicle traveling between 5 and 16 mph.

The active sound generation systems (ASGS) for electric vehicles (EVs) play an important role in improving sound perception and transmission in the car, and can meet the needs of different user groups for driving and riding experiences. The active sound synthesis algorithm is the core part of ASGS. This paper uses an efficient variable-range fast linear interpolation method to design a frequency-shifted and pitch-modified sound synthesis algorithm. By obtaining the operating parameters of EVs, such as vehicle speed, motor speed, pedal opening, etc., the original sound signal is interpolated to varying degrees to change the frequency of the sound signal, and then the amplitude of the sound signal is determined according to different driving states. This simulates an effect similar to the sound of a traditional car engine. Then, a dynamic superposition strategy is proposed based on the Hann window function.

Geometry simplification is a critical step of performing conjugate heat transfer analysis utilizing computational fluid dynamics (CFD). This paper provides a standard methodology to simplify the geometry of electric rotating machines such as electrical generators and electrical motors (both air and liquid cooled). These machines are extremely complex in design and CFD plays an imperative role in their optimization. These machines are extensively deployed throughout aerospace and automotive industries where optimization of weight, volume, and performance is paramount especially given the current global transition to renewable energy sources and vehicle hybridization / electrification.