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Technical Paper
Wayne H Bradley, Marwan Youssef, Robert Graban
The advent of Enhanced Inspection/Maintenance (I/M) Programs brought a need for specialized diagnostics and repair procedures to enable the proper repair of failing vehicles. Unlike previous emission testing programs. Centralized Enhanced I/M Programs such as IM240 present a unique challenge for technicians - the inability to confirm the effectiveness of the repair without the use of similar equipment. This inability to confirm that proper repairs have been made to meet IM240 requirements coupled with a desire not to risk repeat vehicle failures inspired General Motors to investigate all known equipment and procedures relative to this subject GM has conducted a study to measure the effectiveness of various IM240 repair confirmation products and procedures in predicting IM240 outcomes. Appropriate statistical methods were employed to interpret the data acquired in this study. Also collected was vehicle repair and exhaust gas failure information on the vehicles tested.
Technical Paper
Rajneesh Singh
This paper presents the results of a study of CFD simulation of NASCAR's Car of Tomorrow (COT). Aerodynamic flowfield and forces are computed to investigate effects of moving ground and rotating wheel conditions. Mesh dependence and convergence behavior of various forces is also analyzed to develop an accurate analysis process. Thereafter, the analysis process is applied to compute effects of various design changes of the baseline COT. CFD analysis showed that the lift on the COT decreases due to the moving ground and rotating wheel (MVG&RW) effects. However the drag increases, in contrast to the typical observations for passenger cars. This was attributed to smaller interaction of the underbody flow with the wake flow. The aerodynamic force increments for design changes showed that MVG&RW may not be required to estimate effects of some of the design changes.
Journal Article
Raymond Turin, Oguz Dagci, Man-Feng Chang
The focus of this paper is an air charge estimator for engine control system applications which do not feature a mass air flow (MAF) sensor. The proposed approach, beyond its independency of a MAF sensor, is designed to be compatible with the confines of a typical production control system configuration. The air charge estimation algorithm is based on mean-value models for the manifold pressure dynamics and the gas flows through the throttle and valve orifices. It involves nominal static models for the volumetric efficiency of the engine and for the throttle discharge coefficient. The static models for those parameters are complemented with correction factors that are adjusted on-line. The update of the volumetric efficiency correction is implemented in the form of a Kalman-filter which uses the difference between the measured and the modeled manifold pressure as an error metric.
Technical Paper
Terence J. Clancy, William A. Elliott, Donald E. Malen
A method for structural analysis using cast plastic scale models is presented. The method was used to predict the dynamic structural response of a vehicle powertrain using one-half scale cast Polyurethane models of the engine block and transmission case. The results of the model test program allowed the design to be modified to meet structural objectives before tooling commitments were made.
Technical Paper
Kumar Mahadevan, Paul Liang, Jim Fekete
The effect of strain rate in a full vehicle frontal crash analysis is investigated. The strain rate properties obtained from the Auto-Steel Partnership (A/S P) project are utilized in this investigation. Johnson-Cook material model that incorporates strain rate was used in the analysis. The analysis was done with and without strain rate using two vehicle front impact models. Results of the analysis were compared to the test data for deceleration and dynamic crush. The results from this study indicate that incorporating strain rate in the frontal crash analysis yields dynamic crush estimates that are closer to test results. Therefore, strain rate material coefficients should be considered for frontal crash analysis application.
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