Research And Development Of Electronic Control System For Hydraulic Hybrid Vehicle

Based on operating principle of some typical hydraulic hybrid power system, Parallel Hydraulic Hybrid Vehicles(HHV) is studied in this paper. The electronic control system was designed, made and debugged, the main research works includes the following aspects.Firstly, the background and significance of the hydraulic hybrid technology was introduced, through reading a lot of relevant literature, the research status of hydraulic hybrid technologies at home and abroad were summarized, and the key technology of the future development for the hydraulic hybrid vehicle was discussed. After analyzing the working principle and character of some typical hydraulic hybrid power system, a kind of Parallel Hydraulic Hybrid System was chosen as the basic structure in this paper. A parallel hydraulic hybrid system scheme was offered, and the operation modes of HHV were divided.Secondly, the hardware function of hydraulic hybrid electronic control unit was analyzed, the whole scheme of the hydraulic hybrid control system and the hardware circuit was designed. In this paper, we choose a16-bit Single-Chip Microcomputer MC9S12XDP512which was produced by freescale company as the system’s core control unit. The main design contents of hardware circuit were as follows:the least system design, power support and power voltage detection circuit design, the input signal conditioning circuit design, the control signal execution circuit design and communication interface circuit design, and so on.Thirdly, the control strategy of electronic control system was discussed, included: start-stop control strategy while the engine was at idle speed, the brake force distribution control strategy, and fuzzy-PID control strategy of variable displacement pump/motor displacement adjustment. After analyzing the software function of hydraulic hybrid electronic control unit, the main program and the branch program of control system were designed, the branch program included:signal collection module design, every operating mode program design, and CAN communication program design. The system software was debugged under the software Code Warrior V5.1environment, which was the developing tool of Freescale Single-Chip Microcomputer.Finally, the whole system was tested. The testing works were developed on the test bed of engine power system, which was developed by AVL company. The results of software debugging and bench tests indicated that hydraulic hybrid electronic control system in this paper can realize the basic operating requirement of HHV.