Development of combustion control map for flex fuel operation in methanol powered direct injection SI engine

Abstract

The current study proposes a model-based calibration strategy for developing an optimum combustion control map in furtherance of flex-fuel operation with methanol-gasoline blends. Furthermore, a model is developed through the response surface methodology (RSM) for the engine parameters and responses based on the experimental results. In addition, a multi-objective optimization is enacted that relies on a desirability approach keeping equal attention to engine performance and exhaust emission characteristics. The established RSM model exhibits a reliable prediction ability across the operating realms of the engine. Thereby, it has been explored the tendency of parameter calibration and its effects on the engine responses for gasoline and methanol-gasoline blends are studied. From the optimally calibrated map, the test fuel of M30 shows the highest value of brake thermal efficiency (BTE) of 30.76 % and the lowest level of brake specific fuel consumption (BSFC) is recorded for M0 about 147 g/kWh. Besides, the maximal value of 1.70 %vol, 13.96 %vol, 268 ppm, and 535 ppm is observed in the engine exhaust for carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC), and nitrogen oxides (NOx) respectively despite of fuel used. Moreover, the validation results assure and reveal identical outcomes with predicted values within the allowable errors.