Study On Electronic Control Injection System For Natural Gas Engine

ABSTRACT:In the 21st century, the natural gas was considered as one of the most potential clean alternative fuel because of its prominent characteristics of rich resources, cheap price and so on. With the natural gas automobile expanded application, as well as the electronic control technology further developed, the control function of engine electronic control system requires stronger than before. Therefore, study on the electronic control technology and further improvement of the performance of natural gas engine has important academic significance and engineering values to in-depth study on the gas engine control theory and performance optimization of clean alternative fuel engines.Through in-depth analysis of the current situation of natural gas engines, the electronic injection system of WT615-type natural gas engines was designed, the type selection analysis of sensors and actuators used in the injection system was conducted, and single point injection system of natural gas engine was refitted.Through the study on the control method of the electronic control injection system and characteristic analysis of electronic control system, different air-fuel ratio control method was adopted with different working condition of engine and the incremental PID control theory was adopted as a theory of closed-loop control algorithm. A study on control strategy of single point injection system was conducted and the corresponding real-time control software was developed, this software realized the control of injection duration and injection timing of natural gas.In order to shorten the development cycle of ECU and reduce the workload of matching test, a communication module based on CAN bus protocol was developed between the calibration software and ECU, the calibration software can read and write data in the ECU memory. The functions of block calibration, curves calibration, MAP calibration and real-time display of data in ECU memory buffer were developed.Signal generator, potentiometer and other devices were used to analog sensors to generate signals, the software and hardware of the injection system developed was debugged and injection simulation test was completed. The test results show that the control software enables accurate control of the injection timing and injection duration of natural gas.A preliminary matching test of engine and electronic control system was conducted and a preliminary calibration of injection MAP was completed. The test results show that the engine power, economy and emissions basically meet the design requirements and the engine has a smooth operation in the idle condition. ECU's actual control effects have been tested.