Research And Development Of Electronically Controlled EGR System For Hydrogen Fueled Engine

Because of the advantages of energy and environment, many countries are actively developing hydrogen fueled engine. In order to solve the problem of NOx emissions on hydrogen fueled engine, the principle of exhaust gas recirculation (EGR) in controlling the NOx emissions is analyzed. Electronically controlled EGR system, which is very important for control of NOx emission on hydrogen fueled engine, is researched and developed.In this paper, the scheme of EGR system is first analyzed. A total design scheme of hydrogen fueled engine is worked out. Sensors and EGR valve are decided. Then main functions of electronic control system are analyzed. Based on software GT-POWER, hydrogen fueled engine is simulated, and emissions performance of the engine after used EGR system is predicted. The results indicate that NOx emissions are reduced markedly. In this paper, MC9S12DP512 16 bits micro controller unit is the most important part of the system. Electronic control unit is designed, including clock circuit, reset circuit, power supply circuit, signal processing circuit, communication circuit and driven circuit. PCB board of electronic control unit and PCB board of driven circuit are developed. According to the idea of hierarchical and modular design, the development of control software is divided into five functional modules, including initialization module, signal acquiring module, logic control module, driver module and serial communication module. And control tasks of electronic control system are achieved. Related to software design of monitor system, software LabVIEW of graph design tool is used. Based on RS232 serial communication standard, the data transmission between computer and ECU is achieved, and real-time control, display and storage of data is completed.The test of electronic control EGR system has been carried out and the results show that the basal functions of ECU are achieved. It can acquire signals from sensors, communicate with computer and drive EGR valve. The result of the drive characteristic test shows that EGR valve driving system satisfy system requirement.