进气温度对直喷式柴油机冷起动初始期燃烧和排放的影响

Effect of Intake Air Temperature on Combustion and Emissions of Direct Injection Diesel Engine during Preliminary Start Phase

为了研究进气温度对柴油机起动过程燃烧不稳定性和排放的影响规律,利用柴油机起动过程燃烧、排放测控系统,在一台直喷式单缸柴油机上进行了试验。试验结果表明:进气温度对柴油机冷机起动过程初始期燃烧有较大影响,随进气温度的升高,冷机起动着火滞后期明显减小,扩散燃烧增加。提高进气温度能够明显改善着火条件,降低起动过程供油量,减少失火循环,从而明显改善起动过程中的HC排放。

The temperature of intake air is a key parameter affecting the misfire and unsteady combustion during engine starting. In order to study the effect of intake air temperature on the combustion and emissions during starting, the experiments were conducted on a single-cylinder direct injection reseach diesel engine by using the control system of combustion and emission. The results show that the temperature of intake air has a great effect on the combustion during the preliminary start process. As the intake air temperature rises, the ignition delay decreases and the diffusion combustion increases. By means of increasing the intake air temperature, the ignition condition can be improved sigificantly, and the fuel supply during engine starting and the misfire cycle can be reduced, thus the HC emission during starting can be decreased obviously.