进气氮气含量对柴油机混合气形成与燃烧过程的影响

在一台可以拍摄气缸内混合气形成和燃烧过程的发动机上，用高速摄像机研究了进气中加入不同浓度的氮气（N2）后柴油机的油束发展，混合气形成，着火以及燃烧过程， 同时还采用三基色法对高速摄像机拍摄的燃烧火焰的照片进行了温度场分布的计算分析。拍摄的图像和计算结果表明，加入了不同比例的N2，对燃油束的雾化及混合气的形成过程没有影响，对滞燃期的影响也不大，但对火焰的燃烧最高温度和燃烧室的平均温度降低影响很大。N2的加入量越大，燃烧温度下降越多，燃烧过程结束的也就越早。

Influence of Intake Air Mixed with N2 on Combustion Process in a Diesel Engine

The effects of N 2,with various concentrations in the charging air on the mixing and combustion process were investigated on a single-cylinder 1.04 L direct-injection optical diesel engine in terms of the spray development,fuel and air mixing,ignition and flame development by high speed CCD technology.Analysis of these images obtained by the three basic-color temperature analysis method revealed that the different concentrations of N 2 did not affect the fuel spray developing and fuel/air mixing,but delayed the ignition delay period and had remarkable influences on the maximum combustion temperature as well as the average temperature.The experimental results also show that the more N 2 in the charging,the worse the burning stability.