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A new wheel end concept was designed and developed to allow sport utility vehicles (SUV) and light trucks the possibility of achieving a negative scrub radius. This paper will compare a production vehicle with a scrub radius of 54.8 mm with the same vehicle modified with several alternate scrub radii. The vehicle changes are completed in a way that still packages the brake components and meets the component durability needs of a light truck wheel end load cycle. Quantitative vehicle computer analysis and actual instrumented vehicle performance data will be compared and correlated to analyze the effects of scrub radius.

There is paucity of literature on temperature generation in the reciprocating contacts. The objective of this paper is to demonstrate development of closed form solution for temperature rise at the non-lubricated piston ring/bore interface of the oil-less /oil-free air brake compressor. The solution will depend on parameters of reciprocating motion of the piston, gas load, piston ring geometry and thermophysical properties of the ring and bore material. The problem is reduced to solving the three-dimensional diffusion equation for a rectangular source of heat involved in a reciprocating motion. The solution is presented in an integral form. The temperature instabilities typical for a line source of heat are avoided by using a rectangular source of heat. The final results are obtained using numerical integration. Various cases of practical interest such as fast and slowly moving piston, long and short piston strokes are considered using a computer program.

The design of wheel hubs must be based on stresses generated under customer usage through operational loads acting on the wheel. Therefore, the service loading conditions must be taken into account as well as the generated stresses and the hub fatigue properties. In this paper the decisive parameters for design and durability - operational loads, fatigue properties, which depend on material and manufacturing technology, and design - are discussed and the procedure for an optimum light-weight design is treated. Finally, the test procedure for durability approval, the corresponding test facility, the test programs and requirements, and some typical test results are presented.

Mobility method is used to analyze the steady-state performance of crankshaft and connecting rod bearings which are subjected to loads whose magnitude and direction both vary in time. The steady-state characteristics include journal center orbit, minimum film thickness, maximum film pressure, effective temperature, flow through the bearing, etc. To extract the stiffness and damping coefficients over the load cycle, linear analysis method based on a short-bearing approximation is employed. In addition, the oil flow through the main and connecting rod bearings is investigated. Sufficient lubrication conditions for these bearings are discussed. This combined analysis is supported by numerical simulations. The case studies are based on AlliedSignal's two-cylinder truck air brake compressor, TU-FLO 550, which illustrate the entire approach.

Air spring systems are increasingly used on suspensions for commercial vehicles. To prove their durability a reliable test procedure is necessary: to be applied already in the development stage to be used to qualify individual air spring manufacturers and to assure manufacturing quality. In this paper the test procedure, the test facility and some test results are presented. In the test facility the air spring is mounted on a fixture and is loaded by a servohydraulic actuator. The mounting of the air spring allows to simulate all operational deformations, being decisive for the durability. Based on the extensive measurements on proving ground and public roads the test program was worked out. The test program includes besides the loading and deformations during driving also kneeling operations as well as high and low temperatures. The accelerated laboratory tests deliver results which correspond to the existing experience at the service usage.

Primary driving instrumentation for light, medium and heavy-duty trucks has experienced significant changes over the last 10 years. Changes to truck instrumentation continue at staggering speeds as new technologies are applied. Truck electronics has typically been a follower of the automotive industry in the areas of electronic modules, electronic engines, data link systems and other features. Part of the reason is that the market consisting of the fleet owners, individual owner-operators, maintenance personnel and other truck operators were not ready to accept automotive industry technology. Today, the total electronic content in trucks is increasing in value every year. This paper explores the trends in truck primary driving instrumentation from the 1980's looking forward over the next 5 years.

This paper will focus on current products, future products and products currently under development relating to instrumentation for the Asian market. Topics of discussion will include such items as Intelligent Transportation/Navigation Systems, Laser Radar Scanning Systems, Advanced Vehicle Control and Safety Systems and other topics relating to Clusters and Instrumentation.

A simple tire tread model predicts numerous tire performance characteristics. The macro behavior of the rubber gripping the road under vertical load and horizontal force is hypothesized and used to model heat generation in the contact patch. Contact patch heating explains trends of tire performance with slip, pressure, load, camber, tread thickness, and several rubber characteristics. A pressure supported radial wound toroid tire body model is used to evaluate tire deflection, spring rate, and tread momentum loss variation with speed and load. Tire deflection and momentum loss changes with speed together with slip losses can be used to optimize high speed tire performance. New insight to the true effects of camber, tread heating, tread momentum, and surface rubber sliding is presented that is not covered by other works. The new hypothesis of sliding in the contact patch, slip and re-grip, may lead to new understanding of other tire phenomena.

Rear underride crashes kill thousands of people yearly worldwide. Underride guards did not follow the progress achieved by the automotive safety technology. Searching for solutions to this problem, two new guards have been designed and three crash tests carried out. A new articulated, an energy absorbing conceptual guard and a guard constructed according to the European (ECE-R58) regulation were tested. Both the new guards could avoid underride, the ECE-R58 one could not. The tests pointed out that the new articulated guard could be used after a few modifications and the conceptual one needs further optimization to become commercially feasible.

This paper is a discussion on a statistical problem solving approach to determine the root cause of shimmy in a Chrysler Jeep® Cherokee. A blend of statistical approach with strong analytical quantification is used to give the problem solving a non-subjective flavor. The statistical aspect of the problem solving consists of DOE (Design of Experiments) while the analytical portion describes the instrumentation, data acquisition and analysis.

The slip circle, COMBINATOR, model was developed to predict combined driving or braking and cornering performance of tires from straight-line torqued data and free-rolling cornering data only. In the original COMBINATOR paper, limited verification was presented. In the current paper, the model is shown to be broadly applicable to tires of all types. This is demonstrated through successful modeling of heavy-duty tires as large as 425/65R22.5 and by modeling of racing tires. The heavy duty tire models and summarized data are available from SAE Cooperative Research on electronic media.

The objective of the project was to equalize the coolant and component temperatures throughout the engine and to eliminate any localized “hot spots”. A designed experiment was conducted to determine the effect of various parameters on the distribution of coolant flow through the internal coolant passage system of a NASCAR Winston Cup racing engine. The recommended configuration which includes internal passage restrictors and external coolant lines considerably reduced the temperature differential throughout the engine and significantly reduced the temperatures of localized “hot spots”. On track testing confirmed the results gathered during the dynamometer testing. The analysis of several engines upon the completion of actual competition validated the effectiveness of the recommended coolant system configuration.

The objective of this paper is to show how a cost-effective hand control system was designed, built and tested to allow an amateur paraplegic driver to compete in a sports racer in SCCA road racing. The hand control system is based on a newly-designed steering wheel; incorporating the throttle, brake and shifting functions. On-board computer data is discussed which demonstrates generation of competitive braking g forces and shows multiple downshifts combined with braking into a chicane at Portland International Raceway. The compact size of the system also make it adaptable to most open wheel race cars.

Requirements for constant track and camber have a much greater priority with commercial vehicles than on passenger cars. The target can be reached by a concept of rigid wheel suspension elements. It may cause some problems due to structural noise (vibration transfer). However, on commercial vehicles with elastic suspended driver cabs the noise transfer problem is considered to be manageable by suitable cab suspension elements, on buses a compromise in the tuning has to be found regarding overall damping.

The SCCA (Sports Car Club of America) D-Sports class allows 2 stroke engines of up to 850 cc and a maximum of 4 cylinders. An 850 cc single crankshaft V-4 two stroke engine has been designed, developed and successfully raced in the SCCA D-Sports class. This paper covers the design philosophy and development history from prototype engine to a reliable power unit that can win major SCCA national races and compete a full season without failure. Piston and cylinder design, crankshaft development and design of intake and exhaust systems that produce acceptable component life and competitive power output is described.

Race teams are interested in understanding the influence of the various structural members on the torsional stiffness of a NASCAR Winston Cup race car chassis. In this work we identify the sensitivity of individual structural members on the torsional stiffness of a baseline chassis. A high sensitivity value indicates a strong influence on the torsional stiffness of the overall chassis. Results from the sensitivity analysis are used as a guide to modify the baseline chassis with the goal of increased torsional stiffness with minimum increase in weight and low center-of-gravity placement. The torsional stiffness of the chassis with various combinations of added members in the front clip area, engine bay, roof area, front window and the area behind the roll cage was predicted using finite element analysis. Torsional stiffness increases and weight from several competing chassis designs are reported.

The performance characteristics of two-stroke engines are highly dependent upon the gas dynamic wave action in the exhaust system. In a tuned high performance exhaust system, negative suction pulses aid induction of charge into the cylinder, while positive waves aid its retention. The timing of these waves is closely related to the acoustic velocity, and is therefore dependent on the exhaust gas temperature (EGT). In advanced engine management systems, the control strategy may be tailored to influence the EGT, and to maximize the beneficial influence of the gas dynamics in the exhaust. Therefore, accurate measurement of EGT is required for development purposes, and real-time feedback could potentially be used as an input to the management system. However, accurate measurement of exhaust gas temperature is fraught with difficulties due to a number of sources of error.

Vehicle accidents caused by driver inattention and drowsiness represent a problem on both European and American roads. In-vehicle technical innovations, such as lane departure warning systems, are seen as a way to reduce the personal and material costs related to such accidents. Daimler-Benz and Odetics have developed and tested a lane departure warning system, based on image processing lane marking detection. A Time-to-Line-Crossing criterion was used to generate an acoustic warning in the form of a “rumble strip noise.” The latter was found to effect the fastest and most appropriate driver reaction. The technology developed for European roads and test results are discussed, as well as how these require adaptation for application to the US road system. A plea is made for enhancement of the technology and standardization of lane markings on American roads.

This paper describes the design and development of the IRL Aurora V8 racing engine for Indy Racing League competition. It addresses the technical and organizational issues which were involved in producing a competitive racing engine in a compressed time period with specific cost and availability targets. GM Motorsports developed the naturally aspirated, methanol burning IRL Aurora V8 (Figure 1) for the production-based 4.0-liter engine formula introduced by the Indy Racing League in January, 1997. The IRL Aurora V8 sub-sequently became the dominant engine in the series, winning every race, winning every pole, leading every lap, and sweeping the Engine Manufacturer, Driver, Team, and Rookie Championships in 1997. The IRL Aurora V8 progressed from initial concept to the race track in 15 months. In order to meet the series' requirements, GM Motorsports engineers defined objectives for engine performance, cost, and longevity.

In spite of environmental issues related to cadmium and its electroplating process, electroplated cadmium is still extensively used in the aerospace and defense sectors. This trend is likely to continue especially for high strength steels because cadmium provides the best known corrosion and embrittlement protection for this application. Consequently, the environmental concerns related to the cadmium electroplating have been addressed using an alternative Zero-waste Physical Vapor Deposition (Z-PVD). This method does not use liquids, it recycles cadmium in situ, and is free of hydrogen embrittlement. The Z-PVD process is now in commercial production for the aerospace fasteners. The quality of the coatings has been at least equal to that of the electroplated cadmium.