Evaluation of energy-exergy performance of CRDI-VCR type diesel engine fueled with Moringa oleifera biodiesel

The primary aim of the presented experimental work is to examine the influence of injection pressure (IP) on the energy-exergy performance of a single-cylinder, CRDI (common rail direct injection)-VCR (variable compression ratio) diesel engine powered by diesel and Moringa oleifera biodiesel blends MB10 (90% diesel + 10% biodiesel by volume), MB20 (80% diesel + 20% biodiesel by volume), and MB30 (70% diesel + 30% biodiesel by volume). The experiment involved operating the engine at injection pressures of 400, 500, and 600 bar, with a set compression ratio of 18:1, an injection timing of 23 degrees before top dead centre (bTDC), and a constant engine speed of 1500 rpm. The energy analysis results demonstrate that an increase in IP decreases fuel intake energy and unaccounted energy, while enhancing cooling water energy, exhaust gas energy, and overall energy efficiency. The maximum recorded energy efficiency was 28.13% for the biodiesel mix MB30 at a heightened injection pressure of 600 bar. The results of the exergy research demonstrate that the available energy of cooling water, exhaust gas, and exergy efficiency improve with an increase in IP. In contrast, exergy rate of fuel intake energy and dissipated energy diminishes as the input power increases. At an injection pressure of 600 bar, minimal entropy formation and an enhanced sustainability index (SI) were recorded for all assessed fuel mixtures. The greatest recorded exergy efficiency and specific energy for the fuel mix MB30 were 27.45% and 1.38, respectively, attained at an injection pressure of 600 bar. The minimum reported entropy production for the MB30 fuel mixture was 0.02 kW/K, attained at an injection pressure of 600 bar. Following a comprehensive analysis of the data, it is found that the fuel mix MB30 exhibits superior energetic and exergetic performance at elevated input pressure.