稀燃增压CNG发动机起动及怠速控制试验研究

Control and Experiment of the Start and Idle of Lean-burn Natural Gas Engine

根据稀燃增压点燃电控调压式CNG发动机的特点,设计了起动及怠速控制策略,对目标怠速、节气门开度、废气旁通阀开度、燃气供给压差、点火提前角、点火能量、空燃比等参数进行控制。在6缸直列单一CNG发动机上进行了起动及怠速调速试验。试验结果表明:通过优化起动燃气供给量、初始节气门开度、起动点火提前角等参数,可以实现CNG发动机快速、可靠起动;通过标定怠速节气门调速和点火提前角调速控制参数,实现了怠速工况稳定运行。

Start and idle control strategy of lean-burn turbocharged spark-ignition EPR（Electronic Pressure Regulator）-based CNG engine are developed according to the operating characteristic of engine. The main control parameters include that desired idle speed, throttle position, wastegate valve position, EPR delta-pressure, spark advance, spark energy and air-fuel ratio. The tests of start and idle were made on a four stroke inline engine fueled with CNG. The results indicate that the CNG engine can start fast and reliably by optimizing the control parameters including start EPR delta-pressure, initial throttle position and start spark advance, etc. Through calibrating idle governor parameters, the stability of idling operation of CNG engine can be improved.