Zero-dimensional single-zone combustion modeling of an SI engine fuelled with alcohol-gasoline blends

This study analysed and compared the combustion characteristics of baseline gasoline (MO) and methanolgasoline blended with a 10% concentration (MIO) in an SI engine using a zero-dimensional, single-zone combustion model. The experiments were performed in a production 4-cylinder, 4-stroke spark-ignition engine with premixed stoichiometric combustion. In the current work, the engine operated at 2000 rpm and 75Nm of torque. The crank-angle resolvedpressure in the intake, exhaust, and in-cylinder was recorded in all experiments. An in-house algorithm was developed in MATLAB to derive the rate of heat release (RoHR) and evaluate mass fraction burned (MFB) curvesfrom the measured in-cylinder pressure data ofthe twofuels. The effect ofvarious heat transfer correlations—Annand, Hohenberg, and Woschni— on the heat release rate was also studied to identify the most suitable model for the specific SI engine. The results indicated that the methanol-blendedfuel (MIO) provided a higher RoHR compared to conventional gasoline fuel (MO). The MFB profile curves revealed the combustion progress ofthe fuels as afunction ofcrank angle. The Hohenberg heat transfer model was better suited for heat transfer to the wall of the engine compared to the other models, as it gave the best fit in the compression phase. The addition of methanol to gasoline results in an increase in the combustion rate at CAI() (10% MFB) due to its higherflame speed propagation and octane rating.