Hydraulic hybrid-driven technology is an effective augmentation to conventional internal combustion engine-driven vehicle to reduce fuel consumption without compromising on the torque and power requirements. It plays a pivotal role during heavy on/off-roading under circumstances of urban traffic, different road conditions and stringent fuel requirements. Hydraulic hybridization today enables the vehicles to achieve high specific torque and power output by implementing regenerative braking technology. Therein, during braking, the kinetic energy available at the wheels can be conveniently captured and accumulated as hydraulic energy in the secondary power source – a hydro-pneumatic accumulator, and reused later while accelerating the vehicle against different loading conditions. In our study, a series hydraulic hybrid vehicle model has been developed and simulated using the Simulink/Simscape environment to demonstrate this state-of-the-art technology. Here, hydraulic power to the traction motor is provided by an engine-driven hydraulic pump, which is operated in an on/off control strategy using a relay based on the minimum and maximum accumulator-pressure thresholds. Further, observed the pump flow on/off behavior and the accumulator charging, discharging behaviour to validate the power requirements from the Federal Urban driving cycle. This rule-based on/off control strategy maximizes the hydraulic pump-off time, which indirectly leads to minimized fuel consumption. At last, the regenerative braking model was developed in Simulink/Simscape, and studied the effect of system parameters on regeneration efficiency.

Keywords: Modeling, simulation, rule-based control strategy, hydraulic hybrid vehicle, regenerative breaking