Effect of injection strategy and load on the performance of a common-rail diesel engine fueled with Jatropha curcas biodiesel–diesel blend

The present work attempts to determine the optimal engine load, fuel injection pressure (FIP), start of injection timing (SOI) and pilot-main injection intervals (PMII) regarding the performance and emissions of a diesel engine fueled with J20 biodiesel (20 vol% Jatropha curcas biodiesel + 80 vol% 0# diesel). A four-factor and three-level full factorial design and response surface methodology (RSM) were employed in the design of experiments and in the analysis of test results. All the models developed using RSM for measured responses like NOX, Soot, HC, CO emissions, brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) were determined to be statistically significant by analysis of variance. Interactive effects between load, FIP, SOI and PMII were analyzed using tri-dimensional response surface plots that were fitted using developed multiple regression models. The multi-objective optimization was carried out using the desirability-based approach of the RSM for minimum emissions and BSFC and maximum BTE. The best condition of engine parameters with J20 was load of 65.71%, FIP of 160 MPa, SOI of 4.02 CA and PMII of 4.40 CA. And the optimal values with a high desirability of 0.866 were 1172 ppm, 0.0061 FSN, 2.78 ppm, 17.53 ppm, 203.818 g/kW h and 40.96% for NOX, Soot, HC, CO emissions, BSFC and BTE, respectively.