Electronically Controlled Lpg Cylinder Direct-injection Technology For Spark-ignition Engines

The paper studies the direct injection of electronic-controlled engine fueled with LPG(Liquefied Petroleum Gas) in the lab condition. The main contents are as follows:A fuel-supplying system for direct injection electronic-controlled engine fueled with LPG in the lab condition, including the primary pressure system, the high-pressure producing device and the injection system with high-pressure, has been developed. Hydraulic-pressure based high-pressure producing device has such advantages as wide fuel adaptability, wide pressure adjustability, little fluctuation of pressure, good seal performance, and etc. The nozzle is made up of the electronic-controlled valve and diesel nozzle.It is described that the electronic control system of the LPG engine under the lab condition. Some circuit of sensors and software are improved.The high energy and capacitor-discharging multi-time ignition system has been developed and applied to the electronic-controlled LPG engine. The experiment results indicate that the reliability of ignition has been improved, and the exhaust of HC and CO has been reduced. However, this ignition system has little influence on the emission of NOx.The experiment that tests the integral performance of the LPG engine of electronic-controlled direct injection has been carried out. Compared with the LPG engine of intake gaseous injection and intake liquid injection, the power performance of the LPG engine that works under the circumstance of direct injection is improved greatly, but the performance of emission becomes worse. It shows that the direct injection system developed needs further improvement.