高辛烷值燃料对HCCI增压发动机燃烧和排放影响的试验研究

The Influence of High Octane Number Fuels on Combustion and Emissions of Supercharging HCCI Engine

在一台经改装的4缸直喷式柴油机上进行了不同辛烷值(RON)基础燃料(PRF)和93号汽油的进气增压(pin)对均质压燃(HCCI)燃烧特性、性能和排放影响的试验研究。结果表明,进气压力增加,发动机缸内最大爆发压力提高,着火时刻提前。增压后,RON对PRF着火时刻的影响减小,汽油的着火时刻滞后于PRF。进气压力增加,HCCI正常运转工况范围向大负荷和小负荷区域都得到拓展。增压后汽油燃料所能达到的最大负荷比PRF高。相同供油量下,进气压力提高,燃烧效率和净指示热效率先增大后减小;最高燃烧效率和净指示热效率均增大。进气压力增加,HCCI发动机的HC和NOx排放降低,CO排放升高。增压后,RON对PRF的HC、CO和NOx排放影响变小,汽油的HC、CO和NOx排放较PRF高。

The tests were carried out on a modified four-cylinder direct injection diesel engine using PRF with different octane numbers and gasoline to investigate the influence of inlet pressure and fuel property on the combustion characteristics, performance and emissions of homogeneous charge compression ignition （HCCI） engine. The results showed that with the increase of inlet pressure, the start of combustion （SOC） advanced, and the cylinder pressure increased. The effects of PRF octane number on SOC were weakened as increasing the inlet pressure. The SOC of gasoline was later than that of PRF. The successful HCCI operating range was extended to the upper and lower load as increasing the inlet pressure. The maxi-mum operating load of gasoline was higher than that of PRF in the case of supercharging. With the increase of inlet pressure, the combustion efficiency and the gross indicated efficiency changes from the increasing trend to the decreasing trend. HC and NOx emissions of HCCI engine decreases and CO emission increases with the increase of inlet pressure. The PRF octane number has a little effect on HC, CO and NOx emissions with the increase of inlet pressure. HC, CO and NOx emissions of gasoline are higher than those of PRF with supercharging.