Abstract: Transmission ratio will change as a step after shifting for an automatic manual transmission (AMT) vehicle. Input speed and output speed of clutch are different due to ratio change and jerk occurs. By using the auxiliary dynamic action of ISG motor, the power source can be quickly controlled in shifting process, and shift performance can be improved for mild hybrid electric vehicle equipped with AMT. On the basis of analysis of shifting process on traditional AMT vehicles, and by combining the features of mild hybrid electric vehicle, a control model of power source is built up, and an advanced shift control strategy in which the control is realized jointly by integrated starter generator (ISG) motor, engine and clutch are proposed. Power source is well controlled and shift shock and power interrupt time are reduced. The bench test results show that the proposed control strategy can more effectively improve the shift performance in comparison to the traditional control strategy.

Key words: Automatic manual transmission, Mild hybrid, Shift performance