Abstract: In order to study the control strategy of the clutch in the start process of a hydrodynamicmechanical automatic transmission,  the hypostasis of the torque converter and the shift clutch in the start process was clarified according to the detailed analysis of the dynamic model of the start process of a vehicle with a hydrodynamic-mechanical automatic transmission. There are different start processes if different start gears were chosen or different road resistances at the same start gear were put forward in this viewpoint. The control strategy of the clutch was designed for different start processes. According to the contrast of two kinds of test data of the start process, the control strategy was analyzed, and the validity of the control strategy was proved.

Key words: shift clutch, dynamics of start process, control strategy of start process , torque converter