Study On Development Of The Electronic Control System For Natural Gas Engine

In recent years, under the worldwide energy shortage and environmental protection background, the natural gas by its prominent merits of rich resources,cheap price and so on, was considered as one of the most potential clean alternative fuel in the 21st century. With the natural gas automobile promoted used, as well as the electronic control technology further developped, the control function of engine electronic control system also requires stronger than before. Therefore, further development electronic control system with high performance is becoming a research hot spot of natural gas engine.The author mainly pay more attention to the development of a new type of multi-chip ECU for natural gas engine, which meets the requirements of various control functions, besides, the multi-chip ECU can effectively shorten the developing cycle and reduces developing costs. The control strategy of fuel injection and spark ignition for natural gas engine is introduced in detail. The electronic control system overall scheme has been designed; the software and hardware for fuel injection system and electronic ignition system have been developed successfully. At the same time, the anti-interference method when designing the software and hardware was adopted.Aiming to shorten the developing duration, optimize the matching experiment, lower the developing costs, a set of engine real-time monitoring system has been developped independently. By the monitoring system, the engine running status online was monitored; the various control parameters of ECU can be adjusted on real time. The monitoring software is based on the personal computer VB program. By using the modularization, visualization programming technology of VB software,the user-friendly interface and convenient operation are available, besides, the program portability and extendibility are good as well. The portable monitoring instrument for vehicle engine has been developped successfully, which provides convenience to the matching experiment; moreover for further develop the electrically controlled engine scan tool to laid the foundation.Considering the cold start difficult of natural gas engine, a set of electronically controlled high-energy, high-frequency direct ignition system has been developped. The system can provide enough ignition energy even if in the badly condition such as lower temperature, high speed and the spark plug carbon deposition. The feasibility of the high-energy ignition system has been confirmed through the simulation test bench. At last, ECU is applied to the CNG engine experiment on test bench. The JL465Q5 gasoline engine was made the study object, a reasonable optimization improvement to the original engine air intake system and the combustion system were redesigned. The bench test of natural gas engine with ECU has been finished preliminary. The results show that the power and the emissions of engine have met the demand basically, the control function of ECU has been confirmed, which is helpful to further optimizing the software and hardware of ECU and matching ECU with vehicle.