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This paper describes the results of experiments that were performed using a Ground Research Vehicle (GRV) at the National Aeronautics and Space Administration's (NASA) Dryden Flight Research Center in Edwards, CA and a comparison with computational results. The GRV is a modified 1984 General Motors (GMC) van and measures 40 feet long and 9 feet high, with a base area of 83 by 83, and it weighs 10260 lbs and holds a crew of up to three. Air data is measured from a nose-boom, 2 global positioning (GPS) units, and an absolute Honeywell Pressure Transducer with 4 Electronic Signal Processor (ESP) scanners and 64 surface pressure ports. This allows for detailed measurements of the surface pressure profiles around the vehicle. The total vehicle drag is estimated from coast-down tests, while the pressure component of the drag force may be calculated by integrating the pressure profiles on the front and base of the vehicle.

A Vehicle-Engine-Cooling (VEC) system computer simulation model was used to study the transient performance of control devices and their temperature settings on oil, coolant and cab temperatures. The truck used in the study was an International Harvester COF-9670 cab over chassis heavy-duty vehicle equipped with a standard cab heater, a Cummins NTC-350 diesel engine with a McCord radiator and standard cooling system components and aftercooler. Input data from several portions of a Columbus to Bloomington, Indiana route were used from the Vehicle Mission Simulation (VMS) program to determine engine and vehicle operating conditions for the VEC system computer simulation model. The control devices investigated were the standard thermostat, the Kysor fan-clutch and shutter system. The effect of shutterstat location on shutter performance along with thermostat, shutter and fan activation temperature settings were investigated for ambient temperatures of 32, 85 and 100°F.

This paper describes a general purpose computer graphics interface for performing detailed two- and three-dimensional studies involving the dynamic response of humans and vehicles during the pre-crash, crash and post-crash phases of a motor vehicle accident. Specifications are provided for human, vehicle and environment models which can be constructed and analyzed using the interface. The requirements of analysis methods which may be incorporated into the interface are examined, and several examples are provided. Finally, the paper illustrates how the interface is used for creating high-level animations to view the resulting human and/or vehicle motion on various output devices such as computer displays, printers, plotters and video tape recorders.

The classical methods of deflection analysis are finding more application to complex automotive chassis frame structures. Much too time consuming for manual application, they are now coming into more widespread use with the aid of high-speed computers. This paper describes a computerized deflection analysis for complete truck frames under the cases of torsion and flexure. The rapid, accurate analysis permits investigation of more design problems resulting in the eventual production of more efficient frame structures.

A nonlinear yaw-roll model for log hauling trucks is developed in this paper. Several nonlinear effects, such as nonlinear tire cornering forces, nonlinear tire aligning moments, and the coupling between the yaw and roll motions, are considered in this model. Using this model, a computer simulation of the directional and roll responses of a logging truck with tractor and pole-trailer configurations is carried out through various maneuvers. Simulated results for the lateral accelerations are compared with those obtained from field tests. Good agreement has been achieved.

This paper describes the simulation model of a backhoe excavator. The model uses a prescribed motion cycle and the objective of the program is to determine the power requirements for each of the cylinders as well as the total engine power requirement. Most computer simulations are developed by expressing the differential equations of motion for the system being studied. The known force inputs to the system are applied and the time response of the system is then obtained by numerically integrating the governing differential equations. This paper on the other hand develops the reverse of this. Utilizing a prescribed geometry and trajectory cycle for a linkage system as the input, the program solves for the types of force inputs that are required to achieve that trajectory. With the time dependence of the trajectory known, the total power required and the power required of each cylinder is also evaluated. A typical excavator linkage is shown in Fig. 1.

A computer simulation was developed to investigate the effect of wind on test track estimation of heavy truck fuel efficiency. Monte Carlo simulations were run for various wind conditions, both with and without gusts, and for two different vehicle aerodynamic configurations. The vehicle configurations chosen for this study are representative of typical Class 8 tractor trailers and use wind tunnel measured drag polars for performance computations. The baseline (control) case is representative of a modern streamlined tractor and conventional trailer. The comparison (test) case is the baseline case with the addition of a trailer drag reduction device (trailer skirt). The integrated drag coefficient, overall required power, total fuel consumption, and average rate of fuel consumption were calculated for a heavy truck on an oval test track to show the effect of wind on test results.

A Computer Aided System (CAS) is developed in order to evaluate off-road wheeled vehicle mobility. The system takes into consideration both vehicle technical parameters and the main specifications of the soil on which the vehicle is expected to operate. Thirty seven vehicle technical parameters organized in nine groups are considered. These groups are: weights, engine parameters, dimensions, performance, transmission, steering, brakes, tires, and self recovery means. The main soil specifications of the soil considered are the soil type (clay, silt, or sand) and the shear and bearing resistance represented by the cone index or the gradient cone index. The evaluation process depends on considering a datum value for each vehicle technical parameter. These datum values or norms are obtained from a statistical analysis study of the technical parameters for a sample of 155 off-road wheeled vehicles representing different schools from all over the world [1].

A class of heavy truck vehicles, characterized primarily by high centers of gravity, was studied using analysis and computer simulation to identify and understand the relationship between directional and roll stability of such vehicles during steady turning maneuvers. Findings of the computer-based study suggest: (1) directional instability (yaw divergence) is possible for such vehicles during steady turning while operating at elevated speeds on horizontal road surfaces, (2) yaw divergence will lead to rollover in the absence of corrective steering action and/or reduced speed, and (3) the primary mechanism responsible for precipitating yaw divergent behavior in such vehicles is the nonlinear sensitivity of truck tire cornering stiffness to vertical load acting in combination with typical heavy truck fore/aft roll stiffness distributions. In addition, the influences of roadway superelevation and driver steering control as contributors to vehicle stabilization are examined and discussed.

In today's world economic environment, the probability for increased product opportunity for any given company is diminishing because we are faced with a maturing world marketplace. Much of the demand for product will come from users who replace existing products with improved and advanced state-of-the-art products that can perform utilitarian services at a more efficient and economic cost. Although advanced design concepts and improved application of engineering principles have resulted in more reliable and longer life product, there still remains a strong need to keep these products performing to meet the level of user expectation.

This paper presents the results of a two-phase Philippine study to determine the actual mileage (km/liter) of in-use diesel and LPG (liquefied petroleum gas or Auto-LPG) public utility jeepneys plying two separate Metro Manila urban routes using both on-road and chassis dynamometer tests. Measured average load factor in on-road tests was 60-70%. Dynamometer tests at 100% load factor utilized drive cycles derived from on-road speed data. A “diesel equivalent mileage” of actual LPG mileage, deemed indicative of LPG “fuel energy conversion efficiency” relative to diesel, was calculated (based solely on fuel heating values and densities) for comparing actual mileage from both fuels. The LPG actual mileage in both on-road and laboratory tests was lower than diesel mileage. In on-road tests, the LPG actual mileage was lower than diesel actual mileage by about the same percentage LPG heating value was lower than diesel’s per liter of fuel.

Predicting fatigue performance in concentrated contacts under thin film (or mixed) lubrication conditions has historically involved various empirical approaches. Typically a lubrication parameter is used in an experimentally derived equation to predict the expected rolling contact performance. However, this model doesn't explain the performance improvements. Enhanced finish bearings have exhibited longer life than standard finish bearings, especially when bearings are operated with thin EHL film. In this paper, the contact surfaces of test bearings were analyzed by using a micro-macro contact model in which the macro-contact was elastic contact, and the micro-contact was elastic-plastic contact. The interior subsurface stress maps were calculated from the real contact surfaces, which included the effects of roughnesses, waviness, and profiles.

A simple contact-point based start of injection sensor has been developed for use in closed-loop injection timing control systems. The main element in this sensor is a highly durable thin film deposited by an advanced ion plating process. This sensor is expected to provide accurate detection of start of injection over all speed ranges. Sensor transient response in the feedback loop is also expected to be fast compared to other types of sensors. This detecting method can easily be applied to many kinds of injectors because of its simple structure. The durability has been confirmed by extensive testing.

This paper describes the development of a high capacity, continuously variable traction drive. The principles of the drive and alternate drive arrangements to suit specific requirements are reviewed. Efficiency, shock load and endurance test results are presented. The design of a prototype unit which has been installed in a farm tractor is discussed. Applications to other self-propelled farm machinery are suggested.

A rear-steering control method for a four-wheel steering truck has been developed. The purpose of this investigation is to develop a control method to minimize the turning radius without the excursion of the vehicle rear end toward the outside of the turn. The basic control concept is to steer the rear wheels so that the vehicle rear end follows the path of the front end. The control method was applied to an experimental medium-duty truck with four-wheel steering system. The simulation and vehicle test results showed the control method to be effective in minimizing the turning radius without causing the excursion of the vehicle rear end toward the outside in short turns.

Water-cooled charge air cooling is being considered as part of various technology solutions in response to 2007 US, 2010 US, EU4 and EU5 emissions standards. As manufacturers determine appropriate engine and vehicle solutions to meet the upcoming emissions standards, charge air cooling requirements are increasing due to higher turbocharger outlet temperatures and pressures, higher EGR rates, and requests for intake manifold temperature control to manage combustion and exhaust temperatures. Valeo and EMP have collaborated on the development and testing of a water cooled charge air cooler (WCCAC), controlled by a 12 volt brushless motor coolant pump. The system design addresses material temperature limitations of air-air aluminum CAC's and has the potential to simplify the packaging of the air induction system.

This paper outlines what a large company is doing on a corporate staff basis to help combat Product Liability problems. Eaton Corporation is multi-national and serves a variety of markets. The extensive and complex line of products dictates the need for a well organized, corporate Product Assurance Program. The program is made up of five thrusts: 1) Corporate Policy, 2) Guidelines, 3) Divisional Committees, 4) Surveys and 5) Training. Utilizing a product development project, the implementation of several elements of Product Quality Assurance are explained. The program was designed for flexibility and emphasizes the chairman's motto to “DO IT RIGHT THE FIRST TIME, EVERY TIME.”

Emissions and in-cylinder pressure traces are used to compare the relative importance of soot formation and soot oxidation in a heavy-duty diesel engine. The equivalence ratio at the lift-off length is estimated with an empirical correlation and an idealized model of diesel spray. No correlation is found between the equivalence ratio at lift-off and the soot emissions. This confirms that trends in soot emissions cannot be directly understood by the soot formation process. The coupling between soot emission levels and late heat release after end of injection is also studied. A regression model describing soot emissions as function of global engine parameters influencing soot oxidation is proposed. Overall, the results of this analysis indicate that soot emissions can be understood in terms of the efficiency of the oxidation process.

A correlation study of vehicle exhaust emissions measurements was conducted by the West Virginia University (WVU) Transportable Heavy-Duty Vehicle Emissions Testing Laboratory and the Los Angeles County Metropolitan Transportation Authority (MTA) Emissions Testing Facility. A diesel fueled transit bus was tested by both chassis dynamometer emissions testing laboratories. Exhaust emissions were sampled from the tested vehicle during the operation of the Federal Transit Administration (FTA) Central Business District (CBD) testing cycle. Data of gaseous and particulate matter emissions was obtained at each testing laboratory. The emissions results were compared to evaluate the effects of different equipment, test procedures, and drivers on the measurements of exhaust emissions of heavy-duty vehicles operated on a chassis dynamometer.

Current trends in environmental and emissions regulations are driving changes in new engine systems, and increasing the need for more effectively sealed joints in exhaust systems. At the high temperatures in these exhaust systems it is difficult for traditional gaskets to provide an effective seal, as they degrade at high operating temperatures. This paper introduces a coating that has both excellent temperature stability and good compliance, thus forming an excellent sealing enhancement for metallic layers in exhaust system gaskets. Temperature stability data is presented along with sealing data, which illustrate the superior performance of this material compared to current systems.