天然气发动机在不同喷射和点火时刻下的性能优化研究

Optimization Research on Natural Gas Engine Performance under Various Injection and Ignition Timing

为解决改装的天然气发动机动力性比原柴油机低,燃料消耗率比原柴油机高的问题,对影响燃烧时刻的喷射提前角与点火提前角这两个重要参数进行模拟实验,研究其对发动机的缸内压力与功率、燃气消耗率的影响,并根据研究结果进行优化设计。结果表明,对于缸内直喷天然气发动机,适当增大喷气提前角和选择恰当的点火提前角能在较经济的情况下提高发动机的动力性;发动机转速增加,点火提前角和喷射提前角也应提前,保证燃料的充分混合和最大化做功能力;在所有转速下,天然气发动机的功率都能恢复到原柴油机的水平。

To solve the problem of that modified natural gas engine＇s lower power performance and higher fuel consumption rate than the original diesel engine, this paper simulates the ignition advance angle and the injection advance angle of these two important parameters which affect the combustion time, study its effect on the engine cylinder pressure, the power and the gas consumption rate. According to the research results, the optimized design is made. The results show that increasing the jet advance angle and selecting the appropriate ignition timing can increase engine power in the economic situation for direct injection gas engines. When engine speed increases, the ignition timing and injection advance angle should also advance to ensure adequate mixing of fuel and maximize power capability. In all speed, gas engine power can be restored to the original level of diesel engine.