Research Of Hybrid Bus Hydraulic Braking Regeneration System

With the development of economy and urbanization process, the number of vehicles increase rapidly, its led to a great increase in pollutants and suspended particulate matter. Researches show that the car’s exhaust emissions are one of the main causes of the haze. Under the double pressure of energy crisis and environmental pollution, developing fuel-efficient cars is necessary to solve the problem. Hybrid vehicles act as an important role of fuel-efficient technology, it is a new direction and has a broad space for its development. Using the hydraulic hybrid technology to the urban bus can ease both traffic pressure and improve the air quality. Based on the hybrid bus hydraulic braking regeneration system, we explored the main factors that influence the braking performance and energy recovery. By matching the key parameters, we improve the energy-saving and environmental protection of the hybrid bus.Urban bus start-stop process frequently, brake friction loss reduces the energy utilization ratio of the vehicle, For this problem, we compared three basic forms of hydraulic hybrid system and chosen parallel hydraulic hybrid system for urban bus; based on the AMESim simulation software, we established an energy recovery and auxiliary power model, we analyzed the working principle of hydraulic braking regeneration system and the parameters of secondary component(hydraulic pump/motor), accumulator and torque coupler. Using AMESim simulation software, we established the model of the hybrid bus.For hydraulic braking regeneration system could not have both braking performance and energy recovery, we proposed an optimized plan for the work, when the bus braking, using two high pressure accumulator in sequence, when the bus starting, using two accumulator at the same time. By using AMESim software, we established optimal accumulator model for hydraulic braking regeneration system, and conducted simulation analysis with different braking original speed.The simulation results show that the accumulator volume and the minimum working pressure and the displacement of secondary component is the main factor affecting the vehicle braking performance and energy recovery. Using the accumulator optimization solution can effectively improve braking performance and energy recovery. At a relatively low braking initial velocity, the improvement scheme can significantly shorten the braking time and braking distance; At a relatively high braking initial velocity, the scheme improve the energy recovery rate while ensure the braking performance.