点火提前角对焦炉气天然气混燃发动机燃烧特性的影响分析

Influence of ignition advance angle on combustion characteristics of engine fuelled with coke oven gas and natural gas blends

为了研究不同点火提前角对焦炉气与天然气混燃发动机燃烧特性的影响,对一台6缸焦炉气发动机,运用CATIA建立其燃烧室模型。在相同的条件下,运用CFD分析软件研究了6种点火提前角(θig)下焦炉气与天然气发动机的燃烧特性。模拟表明:随着θig的提前,缸内的压力、温度、NO生成量的峰值都会升高且提前,当θig推迟到-12℃A以后时,出现严重的后燃现象,使得排放温度升高;当θig提前到-25℃A之前时,NO的生成量和缸内流速迅速增加,快速燃烧在压缩上止点之前10℃A范围内,发动机做负功;当θig为-15℃A时,虽然NO的生成有所增加,但是增加的不是很大,并且压力、温度、快速燃烧都在做功行程接近上止点的位置。

In order to study the influence of different ignition advance angles on combustion characteristics of engine fuelled with coke oven gas and natural gas blends,a combustion chamber model was established by using CATIA for a six-cylinder engine fuelled with coke oven gas. Under the same conditions,the combustion characteristics of engine fuelled with coke oven gas and natural gas blends with six ignition advance angles（ θig） were studied by using CFD analysis software. The results showed that all the peak pressure,temperature,NO generation in the cylinder would increase and advance with the advance of θig. When θigwas postponed to after-12℃ A,a serious afterburning phenomenon would appear and cause the rise of discharge temperature. When θigwas advanced to before-25℃ A,the NO generation and flow velocity in the cylinder increased rapidly,and the rapid combustion occurred before the compression TDC near about the range of 10℃ A,with negative work of engine. When θigwas-15℃ A,although the NO generation increased,the increase was not very large,and the positions of pressure,temperature and rapid combustion occurred close to the TDC in the power stroke.