Coordinated clutch slip control for the engine start of vehicles with P2-hybrid automatic transmissions

The disconnect clutch can be used to start the engine through slipping for vehicles having P2-hybrid automatic transmissions. However, the driver is easily disturbed by the starting process because of driveline vibration. We develop a multiphase control strategy for slip coordination between the disconnect clutch and shifting clutch to improve the driving comfort during engine start. A detailed dynamic model of the whole powertrain, including the engine (ICE), P2-hybrid automatic transmission, dual-mass flywheel (DMF), electric motor (EM), and driving resistance, is established to support the development of the control strategy and analyze the transient behavior of the engine starting process. Simulations are performed using a co-simulation platform based on "SimulationX" software for the dynamic model and "Simulink" software for the developed control strategy. Experiments are carried out on a plug-in hybrid vehicle. Both simulation and experiment results show that the driveline oscillation can be effectively reduced through slip coordination between the disconnect clutch and shifting clutch. (C) 2020 Elsevier Ltd. All rights reserved.