Prediction of Emission and Performance of a Variable Compression Ratio Engine with Gasoline/Ethanol Blend Using Response Surface Methodology

In this study, the effects of ethanol-butanol/gasoline blends (EB۰%, EB۱۰%, and EB۲۰%) on spark ignition engine performance and emissions were investigated for the different compression ratios (۶.۰:۱, ۸.۰:۱, and ۱۰.۰:۱), and different load conditions (۲kW, ۴kW, and ۶kW). Based on the experimental results, the response surface methodology has been used to develop a model and to estimate the outputs of brake thermal efficiency, brake-specific energy consumption, carbon monoxide, hydrocarbon, and oxides of nitrogen. The optimum operating conditions, ۹.۹۷۰% of the ethanol-butanol blend, ۱۰.۰:۱ compression ratio, and ۶ kW of engine load were obtained through the desirability approach of response surface methodology. Brake thermal efficiency, brake-specific energy consumption, carbon monoxide, hydrocarbon, and oxides of nitrogen at optimum conditions are ۳۵.۰۴۱ %, ۰.۴۹۳ kg/kWh, ۰.۲۱۷ %, ۲۱۳.۵۷۵ ppm, and ۱۲۶۳.۷۸۷ ppm, respectively. Moreover, the developed models have higher R۲ values near ۱, and the optimum responses are obtained with a higher desirability value of ۰.۷۶۸. Ethanol-butanol/gasoline blends improved the brake thermal efficiency, carbon monoxide, and hydrocarbons. Whereas it increased the brake-specific energy consumption and oxides of nitrogen.  In addition, the validation test results illustrate that the acceptable error rate between optimized values obtained through the desirability approach of response surface methodology and experimental values is below ۷%.

کلیدواژه ها:

Oxygenate ، Spark ignition ، Carbon monoxide ، optimization and Response surface methodology