Research On Recycling And Regenerating Of Braking Energy Of Parallel Hydraulic Hybrid Vehicle

Develop energy-efficient and environment-friendly hybrid vehicles is the main direction of automobiles new technology. Hydraulic hybrid vehicles equipped with the energy storage device with high power density, ability to implement energy conversion rapidly and recycle braking energy highly efficiently. Hydraulic hybrid vehicles have become a new hotspot in the research field of hybrid system because it can achieve to decrease traditional engine fuel consumption and emission effectively.In order to research braking energy recycling and regenerating about the parallel type hydraulic hybrid vehicle, this paper designs an energy management strategy that decides the dynamic distribution of the torque by adjusting the displacement of hydraulic pump/motor. On the basis of without sacrificing conventional power performance and ensure security of braking, this strategy aim at increase the degree of braking energy recovery and reuse as far as possible, and improve the engine fuel economy and reduce emissions.In this paper, the mainly work are shown as follows:(1)Introduced the characteristics and the basic working principle of several typical structure mode of hydraulic hybrid system, in view of the actual situation of modified vehicle, determined the research of the parallel hydraulic vehicle.(2)According to analyze the characteristic and control method of hydraulic second element, the goal of adjust torque by controlling hydraulic pump/motor displacement is realized. Compared with three kinds of parallel scheme for torque coupling, determined the form that the transmission is placed in front of the coupling device.(3)Based on torque requirements of vehicle which reflect as driver intention, torque of power source between engine and hydraulic assistant power station is distributed. At the same time, torque is distributed dynamically by regulating hydraulic pump/motor displacement. Braking energy recycling designed a parallel brake control mode combining hydraulic regenerative brake and traditional mechanical brake, which prior to adopt regenerative brake. Energy regenerative drive applied assistant drive parallel control with engine drive so as to maximize the braking energy recycle and regeneration.(4)Refer to vehicle structure, the whole vehicle physical simulation model is built by AMESim, the author established the traditional car parts model such as the engine model, the transmission model, vehicle model and hydraulic regenerative system components model involve the hydraulic accumulator model, hydraulic pump/motor model and so on. While control strategy is modeled in the Simulink platform, the Co-simulation is realized through the interface communication connect with each other, this way of simulation allowed full play to the advantages of respective platform software, consequently, the efficiency of simulation is also enhanced.(5)Under the working condition of UDDS, the Co-simulation of the whole vehicle dynamic model is carried out. Contrastive analysis simulation results between the traditional vehicle and the hydraulic hybrid energy-saving vehicle, so that the effectiveness of control strategy can be tested. The simulation results show that the hydraulic energy-saving vehicle make fuel consumption reduce by 20% compare to the tradition vehicle in this working condition, and the vehicles is often situated on city working condition which obtain better effectiveness of energy-saving and emission reduction than others.