直喷汽油机喷油器热负荷和积碳的试验

Experimental Study on Thermal Load and Deposits of Injector in a Gasoline Direct Injection Engine

在一台缸内直喷汽油机上采用喷油器温度测试装置,进行了不同参数对喷油器温度影响的研究以及喷油器温度对积碳形成影响的研究.结果表明:随负荷增加,密封环上游和密封环处的温度明显降低;密封环下游温度先增大后略有下降;头部温度增加至132~147℃,但远小于汽油90%蒸馏温度(190℃).燃油对喷油器有极高的冷却作用;燃烧相位推迟,喷油器温度小幅降低;喷油器温度与水温呈线性关系.在小负荷下喷油器头部容易形成积碳,提高头部温度有助于减少积碳的形成.

The effects of variable parameters on injector temperature and effect of injector temperature on injector deposit formation were conducted on a gasoline direct injection engine through a special temperature testing device.Results show that with the increases of engine load,the temperature at the sealing ring and upstream decreases;the temperature downstream of the sealing ring increases at first and then drops slightly;the tip temperature increases to 132—147℃,which is lower than the 90%vol distillation temperature of gasoline(190℃).Furthermore,gasoline has intensive cooling effect on the injector temperature.The injector temperature is linear with the coolant temperature and decreases slightly with delays in the combustion phase.Serious deposits are formed on injector tip under low load conditions.Increasing injector temperature can decrease deposits formation.