Simulation, Experimental Testing and Optimization of Starting and Shifting Control Strategies of DCT Wet Dual Clutches with Respect to Sliding Friction

For starting and shifting processes of dual-clutch transmission vehicle, the combined starting control strategy for dual clutches is proposed to reduce temperature rise of clutch and the dynamics simulation model of starting and shifting is built. For the two different downshift modes during inertia phase, the work and power of sliding friction are comparatively analysed. The results can provide boundary conditions of heat source for thermal equilibrium analysis under two typical starting conditions. During the benchmark test, the extreme starting condition under full load and large gradient and the three typical shifting conditions are set. Then, the sliding friction test is executed. The transmitted torque of wet dual clutches and the speed of driving and driven plates of dual clutches are measured to calculate work and power of sliding friction, and the corresponding temperature rise of wet dual clutches is obtained. Furthermore, the heat generation and heat dissipation conditions under different sliding friction modes are analysed. The corresponding influences on clutch control and temperature rise of cooling oil are also discussed. Based on the simulation and test results, the thermal equilibrium of clutches is analysed. The evaluation indexes of sliding friction work are calculated, and then the starting and shift control strategies are optimized.