Hydraulic Hybrid Propulsion System Design and Simulation

Due to increasing environmental pollution and cost of energy, various solutions such as manufacturing hybrid vehicles have been proposed to optimize the energy consumption of vehicles. hybrid hydraulic propulsion system is used in heavy duty vehicles due to low cost maintenance and high power density compared to electric hybrid propusion system. In this study a hydraulic hybrid propulsion system with series structure and friction brake removal approach is investigated. The proposed hydraulic circuit has the ability to control pressure and flow. This feature causes the braking torque to be applied in all driving conditions by a hydraulic circuit. The pressure and flow control algorithm is explained in two ways according to the driving conditions and the accumulator pressure .In the first case, the braking torque is provided only by changing the flow and in the second case by simultaneously changing the flow and pressure .To confirm the performance of the proposed structure, by applying the desired forces to the pedal, the deceleration is simulated in AMESIM software. The control algorithm has been implemented in this software and the braking capability and the amount of energy stored during braking in different braking modes have been investigated.