二甲醚发动机燃料喷射过程及其影响因素研究

在一台2102QB二甲醚发动机上测量了高压油管两端的压力,在不同的发动机转速、负荷和不同的二甲醚燃料温度条件下比较了泵端、嘴端高压油管的压力,结合喷油器针阀升程信号计算了二甲醚燃料的喷射延迟期和持续期,以及不同二甲醚温度条件下的声速.试验结果表明:二甲醚的弹性模量小,压缩性大,喷射延迟期较柴油的长;二甲醚的温度对喷射的最高压力、持续期和压力波传播速度均有较大影响,二甲醚发动机的供油提前角需要根据发动机的转速和燃料温度重新匹配.

Investigation of Dimethyl Ether Injection Process and Influencing Factors

A 2102QB CI engine fueled with DME(dimethyl ether) was adopted to investigate the injection process and influencing factors.The pressures at the pump end and the nozzle end of the injection pipe were measured at different engine speeds,loads and DME fuel temperatures.The injection delay,duration and sound speed were calculated by combining the signal of the needle valve lift.The experimental results indicate that DME has a lower bulk modulus,which reduces the pressure wave propagation and causes a longer injection delay and duration.The temperature of DME has a significant effect on the injection process.Higher temperature leads to smaller peak injection pressure,longer injection delay and duration.The fuel delivery advance angle of the DME engine should be optimized according to engine speed and fuel temperature.