Clutch Coordination Control for Series-Parallel DHT Mode
Changing 2022-01-7046
As a newly designed hybrid transmission, DHT (Dedicated Hybrid Transmission) owns
the advantages of compact structure, multi-modes and excellent comprehensive
performance. Compared with the traditional add-on hybrid transmission with one
single motor, DHT uses one independent generator for engine starting and speed
adjusting which can be largely improve the driving performance in the mode
changing process. Based on the series-parallel DHT with wet clutch for power
coupling, this paper firstly analyses the power coupling clutch device
functionalities from the power flow viewpoint under normal and limp home
condition. And for the changing process from series to parallel mode, a clutch
coordination control strategy is designed by combining generator fast speed
adjusting with clutch accurately pressure controlling to fulfill the fast driver
intension response and clutch protection. And target torques of power sources
are designed by a model-based method and two PID closed-loop algorithms are
designed for controlling the clutch pressure accurately. Such strategy and
algorithms are verified with vehicle test and the results show that the strategy
can quickly complete the mode changing and driver intension changing with
vehicle jerk within ± 10 m/s3, improving the driving pleasure with
prolonging the clutch lifetime.