Optimization of the through-the-road parallel hydraulic hybrid drive train

Abstract

The through-the-road (TTR) hydraulic hybrid parallel architecture uses regenerative braking system that is placed at the rear wheels. This architecture offers a practical solution for an efficient passenger vehicle because it does not interfere with the conventional drive train. Thus, unlike other hybrid vehicles, this architecture allows the use of hybrid technology on an existing front-wheel-drive vehicle. This paper discusses the development of the architecture that involves the hydraulic circuit design and the optimization of the components size. The study simulates 972 vehicle models on all four segments on Worldwide Harmonized Light Vehicle Test Procedure (WLTP) drive cycle. The simulation finds the suitable model uses a 25cc/rev hydraulic pump, a 50 cc/rev hydraulic motor and a 10-liter hydraulic accumulator. The chosen combination allows the pump and the motor to operate within their limits, and maximizes the use of regenerative braking throughout the full WLTP drive cycle.