Experimental investigation of combustion performance in the dual-fuel gasoline-NG SI engine in the free of residual burned gas condition with skip-fire technique

Spark ignition engines are among the common apparatuses for generating power for various applications. By employing dual-fuel spark ignition engines using gasoline and natural gas and analyzing the variations in burned residual gases within the combustion cycles, the operational efficiency of the engine can be improved. Experimental data were obtained from a one-cylinder spark ignition engine operating at different spark advances, a compression ratio of ۹, and a fuel mixture of ۶۰% gasoline by mass and ۴۰% natural gas by mass under stoichiometric conditions. Measurements were taken under both skip-fire and no-skip scenarios. The raw recorded data were processed to derive the in-cylinder pressure versus crank angle diagram and to calculate the Indicated Mean Effective Pressure (IMEP). Analysis of the ensemble average cycle derived from experimental runs at optimal spark advances revealed that the rate of pressure changes within the cylinder before reaching peak pressure is higher under skip fire conditions. Additionally, a difference of ۵ degrees in crankshaft angle was observed between the optimum spark advance with and without skip fire mode. The standard deviation and coefficient of variation for the IMEP were found to be lower in the skip fire condition, indicating a reduction in cyclic variation with skip fire. Furthermore, the rate of change of the mass fraction burned was higher under skip fire conditions compared to no skip fire mode, suggesting faster combustion in the skip fire condition.

کلیدواژه ها:

Gasoline ، skip fire ، SI Engine ، Burned Residual Gas ، Natural gas ، Dual fuel