Modeling and control of a four wheel drive parallel hybrid electric vehicle

Modeling and control of a hybrid electric vehicle is presented in this paper. A four wheel drive parallel hybrid electric vehicle is built by assembling an auxiliary electrical machine and battery group. Some preliminary instrumentation such as accelerator pedal, brake, clutch pedal position sensors and gear ratio estimation are realized to split torque demand into the two power sources. The first power source is the internal combustion engine and the second one is the permanent magnet electric motor. A rule-based control strategy is developed by setting transition rules between the two power sources. The control strategy is implemented on a proof-of-concept vehicle and road tested. In order to satisfy smooth transient switching between the two power sources, and in order not to disturb the driver by abrupt or retarded transitions, torque splitting is achieved by taking the power source dynamics and vehicle dynamics in the longitudinal direction into account. The internal combustion engine is not operated at its high emission and low fuel efficient regions. Regenerative braking is implemented to charge the electric motor battery pack during braking.