The Study On The Optimization Design Of Vehicle's Powertrain

Currently the vehicle industry has two problems that the lack of oil and the pollution of the environment, and they are more serious in our country. How raise the fuel economy and lower exhaust emission that is one of the important topics to vehicle industry currently. There are some scholars and many experts that do many research works to reduce the fuel consumption and the exhaust emission.The powertrain has great influence on the performance, the fuel economy and the exhaust emission. It is important that the choice of the powertrian to vehicle. This paper introduces how to choose the powertrain.According to the knowledge of the vehicle, it is difficult that raising the performance and the fuel economy and reducing the exhaust emission at the same time. The paper put forward: it is made to the evaluation that the sum of 100 kilometer oil consumption, exhaust emission quantity per kilometer (HC, CO and NO_x ) at the standard work condition and the accelerant time by the weightings. First, making the math model of engine according to the experiment data and the math model of transmission by bond graph; second, the parameter of transmission is made to the variation and the demands of the performance, the gear and exhaust emission is made to the restriction of the algorithm; third, making the functions of performance, fuel economy and exhaust emission by the speed of the standard work condition respectively; final, it is made to the optimization algorithm that the sum of the three functions by the weightings. The optimization method of powertain is better to modern design about vehicles for the demand of the exhaust emission is used.At the end of this paper, it introduces the software that is about the optimization of the vehicle's powertrain, which is complied by Matlab. And it concludes that computer simulation, optimization theory and bond graph are available to the design of the powertrain.