Simulation On Dynamic Characteristic Of CHANASTAR Minicar With Automatic Transmission

Automatic gear shifting is the target which people are seeking over a long period of time.It is the significant sign of automobile evolving to the advanced stage and the important technology which desiderate developing and spreading. The automobile with automatic transmission (AT) has smooth gearshifting and convenient operation. Moreover, it can automatically gearshift in term of optimal occasion,redounding to the improvement of dynamic performance and fuel economy. The amount of cars with AT has increased greatly all over the world. Internal automobile industry of China is in developmental period and domestic cars are increasing gradually of late years. For satisfing the curbstone drivers's request for simple handle, many manufacturers have considered AT as their development direction.In the course of AT reserching, developing and matching with the entire vehicle, the characteristics of torque converter and transmission, together with the integral performance of the power train which mainly consists of engine and automatic transmission, need to be analysed. Base on this, optimization design and combination control can be realized. Using the simulation system, we can divine and analyse the performance of the entire vehicle without actual engine and vehicle. This is a economical and efficient means, especially in the design stage of product.According to the AT minicar project of Chongqing Changan Automobile CO.Ltd., a series of researches have been carried out. Base on the characteristic tests of engine and torque converter, the mathematical models are established using curve fitting. Furthermore, the input and output characteristics of torque converter cooperating with engine are analysed. By analysing the control behavior of drivers, the simulation model of driver is designed using fuzzy control theory. The model has good response charateristic and interference immunity. The kernel of automatic gear shifting is gear-shift schedule and gear shfting is executived according to the control parameters. Heretofore, gear-shift schedules of most AT vehicles in the world are based upon static two-parameters. The dynamic schedule and economic schedule are designed according to the acceleration characteristic and fuel consumption. With provision for operating requirement, the general schedule is designed, too. At the same time, the locking-up schedule of torque converter is determined. According to the dynamical equation of vehicle riding, the system for simulating thedynamic driving mode of AT vehicle is established. With the system, the dynamic and economical characteristics of SC6350B with AT are simulated and compared with the car with MT. The results show that the system can simulate the actual driving status well, the dynamic performance and fuel economy of this car basically meet the technical requirements.The theoretic foundation is provided to the project.