【摘要】 通过一台由多缸柴油机改造的单缸重型发动机，研究了喷油时刻（SOI）、喷油压力和点火时刻（ST）对火花辅助汽油压燃（SAGCI）低负荷燃烧的影响．结果表明：喷油时刻与点火时刻合理配合对保证燃烧稳定性非常关键，在低负荷工况条件下，喷油时刻需在-34°～-20°CAATDC的范围内才能保证混合气被点燃，而点火时刻与喷油时刻控制为2°～18°CA的间隔才能保持良好的燃烧稳定性；提高喷油压力可以拓宽稳定燃烧的喷油和点火时刻范围，同时可以加速火焰传播过程，提高该边界下的指示热效率（ITE）．在循环油量为33 mg下采用80 MPa喷油压力，此时CoV_IMEP=1.3%、压力升高率为0.2 MPa/（°）CA，火花辅助压燃燃烧效率达到96.7%，指示热效率为33.89%.更多还原

【Abstract】 An experiment was carried out on a single-cylinder heavy-duty testing engine modified from a multicylinder diesel engine to study the effect of start of injection（SOI）,fuel injection pressure,and spark timing（ST）on spark-assisted gasoline compression ignition（SAGCI） for low-load operating conditions. Results show that the coordination of SOI and spark timing is critical for combustion stability. The SOI should be controlled within the range of -34° to-20°,CA ATDC to ignite the air-fuel mixture,and the interval of the spark timing and the SOI should be controlled between 2°—18°,CA to guarantee combustion stability. Increasing the fuel injection pressure helps to extend the span of SOI and spark timing for stable combustion,accelerate flame propagation,and improve the indicated thermal efficiency（ITE） under this condition. When adopting a fuel injection pressure of 80 MPa with a fuel consumption of 33 mg per cycle,the ITE of 33.89% and combustion efficiency of 96.7% can be achieved under the CoV_IMEP of 1.3% and the pressure rise rate of 0.2 MPa/（°）,CA.更多还原