AMT control for parallel hybrid electric vehicles

Abstract

This paper focuses on the gearshift control of hybrid transmissions with high primary shaft inertia. This relates to the case of the electrification of a conventional AMT in a pre-transmission HEV configuration. A strategy based on energy considerations, by combining the use of the electric motor torque and the mechanical synchronization torque (by means of a synchromesh), has been developed on a detailed AMESIM transmission model for obtaining a high quality gearshift performance in a hybrid driveline. The electric motor is used to compensate its own inertia by accelerating/decelerating the primary shaft during the first phases of the synchronization. The synchromesh is mainly used at the end of the synchronization as the mechanical energy to be dissipated is reduced to an acceptable level. Beside the primary speed control, an important aspect is to phase the electrical and mechanical synchronization actions in order to optimize the global gearshift time and to guarantee robustness. The gearshift control algorithms have been successfully validated on a plug-in parallel hybrid demo car developed at IFPEN, showing that the electrification of entry-level transmissions is a viable solution for developing affordable hybrid vehicles. © Springer-Verlag 2013.