预喷射对轻型车用柴油机排放性能的影响

摘要

以某轻型车用柴油机为样机,研究了预喷射对柴油机排放及燃油经济性的影响.研究表明:采用预喷射可以对燃烧室进行预热.缩短主燃烧滞燃期,降低缸内最高燃烧温度,从而降低NOx的排放,同时炭烟排放及燃油经济性要好于单纯推迟喷油提前角的单次喷射方案;随着预喷油量的增加,NOx炭烟和燃油消耗率都有所上升,预喷提前角对轻型车用柴油机燃油经济性、NOx和炭烟排放的影响较小;采用预喷射并通过喷射参数的优化可以达到燃油经济性、NOx和炭烟排放的折中优化.%For a diesel engine of light-duty vehicle, the influence of pilot-injection on emission was researched. The result shows that the pilot-injection can preheat the combustion chamber, shorten the ignition delay period and decrease the maximum combustion temperature, which leads to the reduction of NOx emission. Compared with the traditional single injection that delays the injection advance angle only, the soot emission and fuel economy were improved. With the increase of pilot-injection fuel quantity, the NOx, soot and fuel consumption slightly increase. Considering the light-duty diesel engine, the influences of pilot-injection advance angle on NOx, soot and fuel consumption are very little. Finally, the pilot-injection and injection parameter optimization can reach a compromise between fuel economy and NOx and soot emission.