Zero-Dimensional Single-Zone Combustion Modeling of an SI Engine Fueled with Alcohol-Gasoline Blends

Abstract

This study analysed and compared the combustion characteristics of baseline gasoline (M0) and methanolgasoline blended with a 10% concentration (M10) in an SI engine using a zero-dimensional, single-zone combustion model. The experiments were conducted 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-resolved pressure in the intake, exhaust, and in-cylinder was measured during all experiments. An in-house algorithm was developed in MATLAB to derive the rate of heat release (RoHR) and evaluate mass fraction burned (MFB) curves from the measured in-cylinder pressure data of the two fuels. The effect of various heat transfer correlations such as 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-blended fuel (M10) provided a higher RoHR compared to conventional gasoline fuel (M0). The MFB profile curves revealed the combustion progress of the fuels as a function of crank 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 accorded the best fit in the compression phase. The addition of methanol to gasoline results in an increase in the combustion rate at CA10 (10% MFB) due to its higher flame speed propagation and octane rating.