Performance optimization of gasoline engine fueled with ethanol/n-butanol/gasoline blends using response surface methodology

In this research work, the effect of adding oxygenates, ethanol and n-butanol, on the performance and emission characteristics of a multi-point fuel ignition (MPFI) engine is analyzed. The test engine was operated at 20 Nm load with speed between 1600 and 2800 rpm. The performance, combustion and emission characteristics of the engine were analyzed for different oxygenates (ethanol and n-butanol) and gasoline blends (EB5, EB10, EB15, EB20). A response surface methodology (RSM) model was developed using experimental data. The desirability function approach was used to predict the optimum values of the engine performance and emissions. The predicted optimum values of blend, load and speed are 20%, 20 Nm and 2702 rpm, respectively. For the optimum predicated values, the experiments found 20.9%, 0.46 kg/kWh, 0.0145%, 136.45 ppm, 4587 ppm for Brake thermal efficiency (BTE), Brake specific fuel consumption (BSFC), Carbon monoxide (CO), Hydrocarbon (HC) and Oxides of nitrogen (NO x ), respectively. The study found less than 5% variation between the experimental and predicted results for the engine performance and emissions. The study also found that the ethanol/n-butanol/gasoline (EB-gasoline) blends produced better performance and emission results as compared to n-butanol-gasoline (B-gasoline) blends. The EB-gasoline blends displayed 1.8% higher efficiency as compared to B-gasoline blends.