Exhaust gas recirculation effect on the performance of a CRDI diesel engine fuelled with linseed biodiesel/diesel blend through response surface methodology

Biodiesel such as linseed oil can be derived from the feedstock of vegetables without disturbing supplies of food and the ecosystem. An experimental and comparative analysis was carried out to explore the effect of exhaust gas recirculation (EGR) and fuel injection pressure (FIP) on the emissions and efficiency of a CRDI diesel engine fuelled with linseed biodiesel/diesel blend. The engine characteristics were calculated using variable EGR (up to 14%) and adjustment of the injection pressure (up to 600 bar) under various load conditions. Multiple regression models were generated to evaluate responses such as Carbon monoxide (CO), Oxides of Nitrogen (NOx), hydrocarbon (HC), Brake power (BP), and Brake thermal efficiency (BTE) using response surface methodology (RSM). For all blends, a combination of FIP and EGR was employed and their impact was evaluated by plotting response surface contour. In RSM, the desirability approach is used to maximize the performance and minimize the emissions parameters of the engine. Linseed/diesel blend ratio 18.3%, FIP 576.76 bar, EGR 7.07%, and load 5.76 kg were estimated to be optimum for the tested engine. From this methodology, it was found that the optimal value of BTE, BP, HC, NOx, and CO is 19.55%, 1.758 kW, 16.7534 ppm, 505.56 ppm, and 0.0676% respectively.