柴油机燃用天然气制油的氮氧化物排放特性

Nitrogen Oxides Emission Characteristics of Diesel Engine Fuelled by Gas to Liquid Fuel

摘要:

以一台轿车用直喷式柴油机为试验样机，分别燃用五种不同天然气制油(GTL)掺混比例的混合燃油.研究其总的NOx排放，以及NO,NO2,N2O等氮氧化物主要组分的排放特性.结果表明，各GTL混合燃油的NOx排放曲线形态较为接近，低负荷时差异较小，随负荷增加，排放差异增大.NOx排放以NO和NO2为主，各GTL混合燃油的NO排放随着负荷上升而增加，NO在总NOx排放中始终占有最高比例.NO2排放也占有相当比例，在低负荷和高负荷均较低，中间负荷最高，大负荷高温不利于NO2的生成.N2O排放量极低，在低负荷时有一定生成量，中高负荷N2O排放几乎为零，缸内高温不利于N2O排放的生成.随GTL混合比的提高，NOx和NO排放降幅增大，NO2排放有所增加，但总体幅度不大.

Abstract:

A direct injection(DI) engine for the passenger car is chosen as the test sample,and 5 gas to liquid (GTL) blends with different mixing ratio are used.The total NOx emission and the main constituents of NO, NO2 and N2O are analyzed. According to the results, the NOx emission of different GTL blends shows no great difference,and as the load increases,the difference becomes greater.The total NOx emission is mainly composed of NO and NO2.The NO emission of the blends increases as load rises,and NO occupies the biggest proportion of the total NOx emission.However,NO2 occupies a comparatively big proportion.The NO2 emission is comparatively low under low and high load,while it reaches highest under medium load.High temperature and high load are not in favor of the generation of NO2.The emission of N2O is extremely low,and is mainly generated under low load;while under mid and high load,the emission of N2O is approximately zero.As the blending proportion of GTL increases,the NOx and NO emission decrease sharply,while NO2 emission increases a little.