Combined Impact of High Injection Pressure and Injection Timing on the Performance and Combustion of Common Rail Direct Injection (CRDI) Engine Fueled with a Simarouba Biodiesel Blend

This paper discusses the combined impact of high injection pressure and injection timings on the performance and combustion characteristics of a diesel engine using biodiesel ester of Simarouba oil (SOME) blends. A Kirloskar make single cylinder 3.7 kW (5 HP) capacity diesel engine was modified to operate with Common Rail Direct Injection (CRDI) system. Experiments were carried on this engine with CRDI setup, fueled with diesel and SOME biodiesel to optimize the combined Injection Pressure (IP) and Injection Timing (IT). A combination of three different IP of 600 bar, 800 bar, 1000 bar and four different injection timings (IT) of 10°, 18°, 23°, 28° before Top Dead Centre (bTDC) were tested at a constant Compression Ratio (CR) of 16.5, engine speed of 1500 rpm by varying load from 25% to 100% of full load. Maximum Brake Thermal Efficiency (BTE) was recorded at IP of 800 bar and IT of 18°bTDC CA combination for HSD, SOME 20 and SOME 30. Peak pressure and Heat Release Rates (HRR) were studied for IT of 23°bTDC and found maximum values with IP 800 bar for neat diesel (HSD). The findings of this study encourage and emphasize the probability of admitting the higher percentage biodiesel blends with HSD by the make use of a proper combination of high fuel injection pressure and injection timing. Hence it serves to overcome the depletion of neat diesel and its environmental issues.