Control Methods For Improving Energy-conservation And Emission-reduction Of Parallel Hybrid Electric Vehicle

The rapid development of the industry caused a large number of energy consumption and serious environmental pollution, so modern industry should be toward the direction of high efficiency, energy saving and emission reduction as a representative of the modern industrial development. The application of the hybrid technology can effectively solve the energy consumption and environmental pollution. The scholars from all over the world commit to the research of new energy vehicles and a large number of research results are obtained. Of all the results, most striking one is hybrid and electric vehicle. But the battery of the electric vehicle is heavy, the price is expensive. And the battery of the electric vehicle posed a safety hazard. At the same time, the electric vehicle has many shortcomings, such as short cruising range, long charging time, weakness dynamic property and so on. So, the development of the hybrid electric vehicle has received much attention. The hybrid electric vehicles have many advantages, such as mature technology, moderate cost, the long driving range, the strong power and so on. The lower fuel consumption, emissions reduction technology of the hybrid electric vehicles has become an important research topic. In order to meet the demands, this paper studies the advanced method of parallel hybrid electric vehicle to improve energy-conservation and emissions-reduction performance. There are three methods proposed in this paper to achieve this goal. Firstly, the regenerative braking energy recovery strategy is studied, improving energy recovery and reducing energy consumption by the optimization of energy recovery control strategy. Secondly, the integrated torque control strategy is studied, switching power energy based on the real-time traffic reasonable to improve energy efficiency and reduce emissions. Thirdly, the influence of transmission ratio on energy consumption is studied, the ratio optimization model is established aiming at reducing energy consumption, and the reasonable ratio is obtained. The main research contents and results are as follows.A reasonable control strategy of regenerative braking energy recovery is proposed. By analyzing the influence of the parallel hybrid electric vehicle control strategy of regenerative braking energy recovery on the energy recovery rate, considering the security of the brake and braking performance, with the goal of maximizing the braking energy recovery, the optimal model of a new regenerative braking is established based on braking safety and braking energy recovery. The simulation results show that the optimized control strategy can satisfy the requirement of the braking safety and the system can recycle more braking energy. The model established in this paper can improve energy conservation and emissions reduction.The integrated torque simulation and power control strategy based on hybrid system theory is raised. Different operating conditions correspond to different most effective power system. The appropriate power system will be beneficial to improve energy efficiency under different operating conditions. The reasonable power switch control strategy need to be studied. The parallel hybrid electric vehicle integrated torque control strategy research is conducted based on the energy management control theory. The relationship model between the description parameters of the power system state based on hybrid system theory (SOC status and state of charge and discharge, the working state of the engine and motor, etc.) and the required power output state (torque, speed, etc.)is analyzed. Combining the theory of hybrid system, using stateflow (finite state machine), the implementation for the operation of the torque needed to power system state switch control strategy is realized. The simulation results show that the proposed control strategy is efficient. The research result provides the reference for the research of hybrid control strategy.The optimization design of the vehicle transmission system transmission ratio based on genetic algorithm is raised. In consideration of parallel hybrid electric vehicle drive train transmission ratio has huge influence on vehicle fuel consumption and emissions, this paper established the optimization model aiming at minimum energy consumption and exhaust emissions. The solving method based on genetic algorithm is presented. In view of the typical transmission system, transmission ratio is designed. The fuel consumption and exhaust emissions can be further reduced with the optimization of the transmission ratio.