The Design of the Gearshift Controller in a Hybrid Electric Vehicle Equipped with AMT

This paper presents the design and optimization of gearshift strategy for a parallel hybrid electric vehicle (HEV) equipped with automated manual transmission (AMT). For this purpose, an AMT gearshift model –including gearshift actuator, clutch actuator and controller- is initially provided and integrated into a parallel HEV model based on the conventional Samand, to develop a comprehensive simulation tool for vehicle powertrain performance evaluation. In this research, three types of gearshift strategy based on the vehicle speed, the operating condition of the IC engine, and the fuzzy logic are implemented on the gearshift controller. Using genetic algorithm (GA), an optimization problem is then formulated for the optimal design of the AMT gearshift strategy based on the operating condition of the IC engine, to minimize fuel consumption and emissions, while sustaining the vehicle performance.GA optimization process is performed for several traffic conditions of Tehran drive cycle. The results show that the approach is quite effective and considerable improvement in the fuel consumption and emissions is achieved.