聚甲氧基二甲醚火(PODE_n)引燃时刻对HCII燃烧与排放的影响

Effects of induced injection-timing on combustion and emission performances in homogeneous-charge-induced-ignition(HCII) combustion by using polyoxymethylene dimethyl ethers(PODE_n)

为提高均质混合气引燃(HCII)的效率并降低由于引燃柴油预混不充分产生的碳烟排放,在一台HCII原理性单缸机上,分别使用体积分数为0%、50%和100%的聚甲氧基二甲醚(PODE_n)/柴油混合燃料作为引燃燃料研究了在不同引燃燃料喷油时刻下HCII燃烧的燃烧、排放特性和热效率。结果表明:在1 200 r/min,0.3 MPa指示平均有效压力(IMEP)工况下,向引燃燃料中添加PODE_n能够明显降低碳氢化合物(HC)、一氧化碳(CO)排放以及循环变动(COV),提高指示热效率,100%的PODE_n作为引燃燃料时HCII燃烧模式的指示热效率达到甚至超过柴油直喷模式;在1 600 r/min,0.6 MPa IMEP工况下,向引燃燃料中添加PODE_n能够明显降低排气光吸收系数,提高指示热效率。

Combustion, emission characteristics and thermal efficiency were investigated under various induced injection-timing for a Homogeneous Charge Induced Ignition（HCII） to improve the thermal efficiency and reduce soot emissions from under-mixing induced diesel. The tests were conducted in an HCII principle engine using 0%, 50% and 100% volume friction polyoxymethylene dimethyl ethers（PODE_n） /diesel blend as induced fuel. The results show that adding PODE_n can significantly reduce the hydrocarbons（HC）, nitric oxide（CO） emissions, and the Coefficient of Variation（COV） and can increase indicated thermal efficiency at the condition of 1 200 r/min, 0.3 MPa of Indicated Mean Effective Pressure（IMEP）, the HCII induced by 100% PODE_n even has higher thermal efficiency than diesel Direct-Injection mode; and that adding PODE_n can significantly reduce exhaust smoke and increase indicated thermal efficiency at the condition of 1 600 r/min, 0.6 MPa of IMEP.