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This paper presents a method for optimization design of an engine mounting system subjected to some constraints. The engine center of gravity, the mount stiffness rates, the mount locations and/or their orientations with respect to the vehicle can be chosen as design variables, but some of them are given in advance or have limitations because of the packaging constraints on the mount locations, as well as the individual mount rate ratio limitations imposed by manufacturability. A computer program, called DynaMount, has been developed that identifies the optimum design variables for the engine mounting system, including decoupling mode, natural frequency placement, etc.. The degree of decoupling achieved is quantified by kinetic energy distributions calculated for each of the modes. Several application examples are presented to illustrate the validity of this method and the computer program.

Model-based control strategies are important for meeting the dual objective of maximizing NOx reduction and minimizing NH3 slip in urea-SCR catalysts. To be implementable on the vehicle, the models should capture the essential behavior of the system, while not being computationally intensive. This paper discusses the adequacy of two different reduced order SCR catalyst models and compares their performance with a higher order model. The higher order model assumes that the catalyst has both diffusion and reaction kinetics, whereas the reduced order models contain only reaction kinetics. After describing each model, its parameter identification and model validation based on experiments on a Navistar I6 7.6L engine are presented. The adequacy of reduced order models is demonstrated by comparing the NO, NO2 and NH3 concentrations predicted by the models to their concentrations from the test data.

In recent years, the slip lock-up mechanism has been adopted widely, because of its fuel efficiency and its ability to improve NVH. This necessitates that the automatic transmission fluid (ATF) used in automatic transmissions with slip lock-up clutches requires anti-shudder performance characteristics. The test methods used to evaluate the anti-shudder performance of an ATF can be classified roughly into two types. One is specified to measure whether a μ-V slope of the ATF is positive or negative, the other is the evaluation of the shudder occurrence in the practical vehicle. The former are μ-V property tests from MERCON® V, ATF+4®, and JASO M349-98, the latter is the vehicle test from DEXRON®-III. Additionally, in the evaluation of the μ-V property, there are two tests using the modified SAE No.2 friction machine and the modified low velocity friction apparatus (LVFA).

One of the major NVH concerns for automobile manufacturers is the response of a vehicle to the impact of the tire as it encounters a road discontinuity or bump. This paper describes methods for analyzing the impact response of a vehicle to such events. The test vehicle is driven on a dynamometer, on which a bump simulating cleat is mounted. The time histories of the cleat impact response of the vehicle can be classified as a transient and a repeated signal, which should be processed in a special way. This paper describes the related signal processing issues, which include converting the time data into a continous spectrum, determination of the correct scaling factor for the analyzed spectrum, and smoothing out harmonics and fluctuations in the signal. This procedure yields a smooth frequency spectrum with a correctly scaled amplitude, in which the frequency contents can be easily identified.

Tire stiffness can have a significant effect on the spindle and component loads. While its’ effect on the component loads may show a different trend. This paper deals with data acquisition loads using Wheel Force Transducer (WFT) with 17 inch, 18 inch and 20 inch tires and shows how the spindle loads changed for different tire. These loads are applied on the analytical suspension model to generate both component and the body attachment loads. Some of the measured channels are correlated for all the wheel sizes for multiple events to ensure the confidence in the model. It is found that even if spindle loads are increased with tire stiffness, the component loads do not necessarily show a similar trend. This paper studies why higher spindle forces do not always give higher component loads and what are the possible alternatives one may look into to shortlist or select one set of loads over the other.

Determination of an engine's inertial properties is critical during vehicle dynamic analysis and the early stages of engine mounting system design. Traditionally, the inertia tensor can be determined by torsional pendulum method with a reasonable precision, while the center of gravity can be determined by placing it in a stable position on three scales with less accuracy. Other common experimental approaches include the use of frequency response functions. The difficulty of this method is to align the directions of the transducers mounted on various positions on the engine. In this paper, an experimental method to estimate an engine's inertia tensor and center of gravity is presented. The method utilizes the traditional torsional pendulum method, but with additional measurement data. With this method, the inertia tensor and center of gravity are estimated in a least squares sense.

In this paper, a model-based linear estimator and a non-linear control law for an Fe-zeolite urea-selective catalytic reduction (SCR) catalyst for heavy duty diesel engine applications is presented. The novel aspect of this work is that the relevant species, NO, NO2 and NH3 are estimated and controlled independently. The ability to target NH3 slip is important not only to minimize urea consumption, but also to reduce this unregulated emission. Being able to discriminate between NO and NO2 is important for two reasons. First, recent Fe-zeolite catalyst studies suggest that NOx reduction is highly favored by the NO 2 based reactions. Second, NO2 is more toxic than NO to both the environment and human health. The estimator and control law are based on a 4-state model of the urea-SCR plant. A linearized version of the model is used for state estimation while the full nonlinear model is used for control design.

In automotive testing, a chassis dynamometer is typically used, during cell testing, to evaluate vehicle performance by simulating actual driving conditions. The use of indoor cell testing has the advantage of running controlled tests where the cell temperature and humidity and solar loads can be well controlled. Driving conditions such as vehicle speed, wind speed and grade can be also controlled. Thus, repeated tests can be conducted with minimum test variations. The tractive effort required at the wheels of a vehicle for a given set of operating parameters is determined by taking into account a set of variables which affect vehicle performance. The forces considered in determination of the tractive effort include the constant friction force, variable friction force due to mechanical and tire friction, forces due to inertia and forces due to aerodynamic and wind effects. In addition, forces due to gravity are considered when road grades are simulated.

Buffeting is a wind noise of high intensity and low frequency in a moving vehicle when a window or sunroof is open and this noise makes people in the passenger compartment very uncomfortable. In this paper, side window buffeting was simulated for a typical SUV using the commercial CFD software Fluent 6.0. Buffeting frequency and intensity were predicted in the simulations and compared with the corresponding experimental wind tunnel measurement. Furthermore, the effects of several parameters on buffeting frequency and intensity were also studied. These parameters include vehicle speed, yaw angle, sensor location and volume of the passenger compartment. Various configurations of side window opening were considered. The effects of mesh size and air compressibility on buffeting were also evaluated. The simulation results for some baseline configurations match the corresponding experimental data fairly well.

Engine mount loads are mostly measured from load cells or calculated from measured engine accelerations. This paper introduces an innovative new method to calculate engine mount loads from measured spindle loads. The method starts from calculating suspension attachment loads to body or chassis frame, then calculating engine center of gravity accelerations, and finally calculating engine mount loads from engine inertia forces. This spindle-based engine mount load analysis method is validated by a vehicle with measurements by wheel force transducers and engine load cells. The correlation includes load time history, peak-to-peak load range, and pseudo-damage values. The correlations show good comparisons between measured and predicted in all the categories, especially for the high load components. It is recommended to implement this method in early vehicle design phases.

Over 250 million tires are scrapped in the United States each year. Tires have been a problematic scrap because they have been designed to resist destruction, and have a tendency to float upwards in landfills. Improper storage has resulted in tire fires1--an even more problematic environmental concern than unsightly piles which can serve as breeding grounds for insect vectors. A better solution is to recover materials for use in new components. Not only does this resolve the landfill issue, but it also serves to conserve resources, while returning an economic benefit to society. This paper traces the introduction of tire material recovery at NRI Industries and DaimlerChrysler Corporation (DCC), the development of the infrastructure and materials, and the launch of the Jeep Grand Cherokee thermoplastic elastomer (TPE) radiator seals, comprised of post consumer tire crumb.

A traction test machine, developed for evaluation of traction-CVT fluids for the automotive consortium, USCAR, provides precision traction measurements to stresses up to 4 GPa. The high stress machine, WAMhs, provides an elliptical contact between AISI 52100 steel roller and disc specimens. Machine stiffness and positioning technology offer precision control of linear slip, sideslip and spin. A USCAR traction test methodology includes entrainment velocities from 2 to 10 m/sec and temperatures from -20°C to 140°C. The purpose of the USCAR machine and test methodology is to encourage traction fluid development and to establish a common testing approach for fluid qualification. The machine utilizes custom software, which provides flexibility to conduct comprehensive traction fluid evaluations.