A bond graph model for simulating the effects of regenerative braking system on emission of a hybrid vehicle

摘要

Nowadays, vehicles have major role in the transportation of people and goods. The air pollution and fuel consumption are the most important topics in this subject. One of the methods used for reducing fuel consumption is regenerative braking systems. Very few researches have studied the effects of regenerative braking system on emission of hybrid vehicles. In this research, using bond graph method, a vehicle model including combustion, heat transfer, power generation, power transmission, braking, energy storage system and vehicle body is simulated. To determine the amount of pollution generation, an incomplete combustion model and complete gas theory are assumed and Arrhenius equation is used for modelling the combustion reaction velocity. This model can determine fuel consumption in any actual operating condition and also all pollutions generated by incomplete combustion in the engine. This is the preference of this research while most of previous researches using engine fuel map to determine fuel consumption and unable to define all kind of pollutions. The body of the vehicle is modelled with seven degrees of freedom mass-spring-damper model. Also, the hydraulic braking system is modelled by acting braking torque on wheels. Using this vehicle model and its parameters, amount of energy consumption and emission of the vehicle equipped with regenerative braking system are achieved and compared with the results of the same vehicle without regenerative braking system. Simulations are performed on two standard Economic Commission for Europe and extra urban driving cycles to determine regenerative braking system operation effects on reducing fuel consumption and emission in each cycle. Results show that a vehicle with this equipment is capable of reducing fuel consumption and emission in comparing with an unequipped vehicle. Using regenerative braking system in Economic Commission for Europe cycle, in comparing with extra urban driving cycle, is more efficient in reducing emission and fuel consumption. According to the results, regenerative braking system makes more deceleration than Hydraulic Braking System in high speeds.