喷射参数对点燃式重油直喷发动机小负荷性能的影响

Effects of Injection Parameters on Performance at Low Loads of a Spark-ignited Direct Injection Heavy-oil Engine

在一台采用低压空气辅助喷射技术的二冲程点燃式重油直喷发动机上,进行了燃油喷射参数对发动机性能影响的试验研究,研究了中等转速小负荷工况下,喷气结束时刻及过量空气系数对发动机动力性、燃油经济性及排放性能的影响。试验结果表明:节气门开度为10%时,随着喷气结束时刻提前,功率先增大后减小,油耗先减小后增加,HC及CO排放有小幅度减少;混合气由浓变稀时,功率增加,油耗降低,HC及CO排放大幅度减少。节气门开度为20%时,随着喷气结束时刻提前,功率增大,油耗减小,HC排放有小幅度减少,CO排放有小幅度增加;混合气由浓变稀时,油耗降低,HC及CO排放大幅度减少,最大功率出现在理论空燃比附近。

An experimental study on the influences of fuel injection parameters on the engine per- formance was carried out on a two-stroke engine with low pressure air assisted injection technology, and the effects of inject end time and excess air ratio on engine power, fuel economy and emission per- formance were studied under the conditions o{ middle speed under small load. Test results show that at the 10% throttle opening condition, with the end of the inject advance, the power first increases, then decreases, and the fuel consumption first decreases, then increases, and the HC and CO emis- sions are reduced. When mixed gas is diluted, the power increases, the fuel consumption is reduced, and the HC and CO emissions are reduced significant the end of the inject advances, the power increases, have a small decrease, and CO emissions have a sma y. At the 20% throttle opening condition, with the fuel consumption decreases, HC emissions 1 increase. When mixed gas is diluted, the fuel consumption is reduced, the HC and CO emissions are reduced greatly, and the maximum power ap pears in the stoichiomtric ratio.