Fuzzy Optimization Study For The Design Of Automobile's Power Train Parameters And Software Exploitation

The power train has great influence on automobile's power performance, economy performance and emission performance. In this paper, the fuzzy optimization theory is used in the design of the power train's parameters to improve the matching between engine and power train. This can improve the perfonnance of the automobile. A suit of software about this is designed, then at the end of this paper an example is used in this software to prove the correctness of the theories and the practicability of this software.Firstly, the paper discusses the good way to choose the engine, and builds the models of the engine external characteristic and universal performance which include the emission performance. Then introduce the mathematic model of whole transmission, and summarize the assessing index of automobile's power performance, economy performance and emission performance at present. Take these assessing indexes as the base, the paper gives a series of assessing indexes. These assessing indexes which considering different characteristics of driving patterns are fit for different kind of automobiles. It can correspond automobile's power performance, economy performance and emission performance better. Secondly, this paper gives the fuzzy optimization model to the power train's parameter design, which takes the common optimization mode as the base. In this model, the general target function includes three small function, which can reflect automobile's power performance, economy performance and emission performance, and the constrain conditions takes the fuzzy factors in power train's parameter design into account. This model can overcome the limitation in the common optimization mode which may bring on the result that the model can not find the actual best result. This paper use the way of finding optimal level cut set to solve the fuzzy optimization model. We take the result under the best optimal level cut set as the result of this whole model.Based on above theories, uses Matlab as a tool to develop the software of the transmission parameters optimization, it can be operated easily and has a very friendly interface. Except the fuzzy optimization design function, the software can also calculates the indexes of the automobile's power performance and economy performance. At the end of the paper, take Lubao HFJ7110 car as an example, we uses the software to calculate its power performance and economy performance, then calculate its power train's parameter by fuzzy optimization model, analyse the result which shows the correctness of the theories and the practicability of this software. At last the author gives some pieces of advice to go on working on this object.