温度对柴油和二甲醚喷射系统性能的影响

Comparison of Diesel and DME Injection System Performances at Different Temperatures

针对普通油泵-油管-油嘴燃油系统,建立了喷射系统的数学模型。对不同温度下柴油和二甲醚喷射系统性能进行了数值模拟。研究表明:在相同温度下,二甲醚喷嘴压力的上升和下降速率、压力峰值都比柴油低,20℃时二甲醚较柴油下降51.1%,50℃时较柴油下降45.2%,喷射速度和累积喷油量均远低于柴油,针阀开启时刻较柴油明显延后;在最大速度点,20℃和50℃时二甲醚分别较柴油下降38.8%和36.8%。随着温度的升高,柴油和二甲醚的喷嘴压力、喷射速度下降,针阀开启时刻延迟,且柴油的索特平均直径明显减小。

The mathematical model is established for the conventional pump-pipe-injector fuel system. Through the numerical simulations on diesel and DME injection systems, the effects of temperatures on these two injection systems are disclosed, and their differences are illustrated. At the same temperature, line peak pressure and the rate of pressure increase and decrease for DME are lower than that for diesel fuel. Pressure of DME drops 51.1% and 45.2 % than that of diesel at 20℃ and 50℃. DME injection rate and cumulative volume flow through nozzle orifice are much lower than that of diesel. The open timing of nozzle is delayed. DME peak rate drops 38.8% and 36.8 % than that of diesel at 20℃ and 50℃. With the increase of temperature, the diesel and DME pressures in nozzle, injection rate and SMD all decrease, and the open timing of nozzle is delayed.