Regression analysis and optimization of diesel engine performance for change in fuel injection pressure and compression ratio

•Effect of change in FIP and CR on diesel engine performance and emissions is investigated for diesel.•The simulation model is developed to predict the engine performance for original and modified FIP and CR values.•Regression analysis is carried out to find the relation between engine parameters.•Optimum engine performance and emission characteristics are obtained at FIP 220bar and CR 18 combination for diesel. In the present investigation, the single cylinder diesel engine is modified for different fuel injection pressure (FIP) and compression ratio (CR) values to check their influence on engine performance and emissions. Three values of FIP (200, 210 and 220bar) and for each FIP, three values of CR (16, 17 and 18) were used in this study. The objective of this study is to quantify the effect of FIP and CR on different engine parameters. The engine performance parameters like brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), maximum net heat release rate (NHRRmax) and maximum rate of pressure rise (RPRmax) were evaluated. Also, carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC) and nitrogen oxides (NOx) emissions were measured. The regression equations are developed to discover the relation of these parameters with FIP and CR variables. Also, the combination of input parameters that simultaneously optimize the engine performance and emissions is evaluated. The simulation model is developed in Diesel-RK tool for prediction of engine performance for modifications incorporated to the engine. The regression equations and optimization plot obtained in this work form useful data for further study related to FIP and CR modifications. FIP 220bar and CR 18 combination is found to yield optimum engine performance and emissions.