Research On Intelligent Shift Strategy Of AT Vehicle Based On Fuzzy Control

With the assembly of automatic transmission vehicles are increasing in the Chinese market, automatic transmissions are increasing year by year. Hydraulic automatic transmission(AT) has maturated technology after 80 years development, and its integrality performance is stable.AT is the important position of automatic transmission. And it will consolidate important position in the future. Shift strategy quality is the most direct expression for the whole power system matching, which directly affects the vhielce performance, such as economy and power. Shift strategy is the core of AT vhielce control.Therefore, AT intelligent shift strategy research has very important practical significance, and it will be a trend of the shift strategy development.The shift strategy, which based on speed and accelerator pedal, does not consider the driver’s intention and vehicle running environment two factors. This paper introduces the fuzzy control theory, and the intelligent shift strategy consists of three parts: the two parameter shift strategy, the driver intention of a fuzzy modification module, a special road condition of a fuzzy modification module. The related research of this paper is as follows:1. Simple analyse the working principle of AT vehicle. Subsequently compute an engine and a torque converter conbined input and output characteristics in order to obtain two parameter shift strategy.2. Follow the intelligent shift stragety, design three fuzzy controllers in SIMULINK. In SIMULINK, gear will be calculated after simulation with vehicle test INCA data.3. Based on vehicle performance, design three test.Do the test in AT vehicle with no fuzzy shift strategy and intelligent shift strategy with fuzzy control, final analyse vehicle test datas between two shift strategies.In AT vhicle with the same drive manipulate and road condition, intelligent shift strategy with fuzzy control can reflect the driver intention and vehicle running environment(downhill or uphill) on shift strategy.In test, it can improve vehicle’s power performance with driver intention modification and shorten vehicle braking time in the downhill road with spcial road modification.