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针对均质压燃燃烧难以控制的问题,在一台发动机上,改装进排气系统,并加装均质混合气供油系统和进气加热系统,研究了外部EGR(废气再循环)对甲醇HCCI(均质充量压缩着火)燃烧与排放特性的影响。结果表明:外部EGR对甲醇HCCI燃烧过程和排放都有显著的影响,随EGR率的增加,CA10、CA50逐渐推迟,燃烧持续期逐渐延长,但影响的程度因混合气浓度的不同而变化;HC和CO排放逐渐增加,且增加的幅度逐渐变大;NOx排放仅在混合气较浓时存在(过量空气系数小于1.5时),且随着EGR率的增加迅速下降。
Aiming at the problem that the homogeneous compression ignition combustion is difficult to control, an EGR engine was used to retrofit the intake and exhaust system and a homogenous mixture gas supply system and an intake air heating system were installed. The effects of external EGR (exhaust gas recirculation) HCCI (homogeneous charge compression ignition) combustion and emission characteristics. The results showed that external EGR had a significant effect on HCCI combustion process and emissions. With the increase of EGR rate, CA10 and CA50 gradually delayed and combustion duration gradually extended, but the degree of influence varied with the concentration of HCG. HC And CO emissions gradually increase with a gradual increase. NOx emissions are only present when the air-fuel mixture is relatively rich (the excess air ratio is less than 1.5) and decrease rapidly with the increase of the EGR rate.