Engine Upgrading And Optimal Matching Of An Automotive Powertrain

This paper takes transmission system of a SUV as the research object, and then researches on the matching of the vehicle performance and the parameter optimization of the transmission.This thesis firstly builds the SUV simulation models on the basis of vehicle performance simulation GT-DRIVE software and simulates its dynamic and fuel economy. By comparing the simulation results with the real vehicle test results, it verifies the possess precision of the simulation model.The problems presented in the original engine were analyzed and improvement of fuel injection system, supercharger, material and EGR system were put forward. Universal characteristic of the engine were found through stand test. By analyzing the improved engine and original car's transmission, the simulation results show that the economy and emissions have improved. However, the grade ability is not so satisfying.In order to further refine the dynamic property of the vehicle, fuel economy and discharge, this paper optimizes the parameter of the transmission system by taking dynamic as target, economy and emissions as constraints to optimize the parameters of the transmission system. The final optimized results show that the dynamic has been enhanced, the maximum vehicle speed increased 10.5km/h,0-100km/h acceleration time decreased 2.9 seconds, directly gear 50-100km/h acceleration time reduced 3.3s and the largest grade increased 7.8%, which offsets the disadvantage of the improved engine. At the same time, the economy and emissions have been improved, fuel consumption of driving cycle UDDS and NEDC decreased 0.30 and 0.36L/100km. Emission have reached EuroⅢstandard compared the original car's EuropeⅡstandard.This paper effectively combined the engine performance improvement and transmission optimization matching technology, based on existing models to improve power and emissions, and also improved fuel economy slightly, so the performance of the vehicle get a larger increase in the overall. With the support of CAE model and analysis technology, it makes the optimization process of existing vehicles quicker and cost lower.