Multi-objective optimization of CRDI engine characteristics powered with Mahua methyl ester/diesel blend: a Taguchi...

An investigation has been conducted on a CRDI (common rail diesel injection) engine utilizing a blended fuel using mahua methyl ester to explore the influence of fuel injection strategies (i.e., FIP, CR, and FIT) on the engine characteristics. It is observed that specific fuel consumption (BSFC) and nitrogen oxide emission (NO_x) increased with a decrease in brake thermal efficiency (BTE) in the case of MME100 at a base FIP of 500 bar. The volatility and viscosity (physical properties) of the MME fuel blend influenced the combustion phenomena resulting in a reduction in engine performance. The higher viscosity of the methyl ester blend restricts the fuel atomization process during the injection. Fuel injection pressure (P_inj) was raised from 500 to 1000 bar in increments of 250 bar in the first phase to maximize the use of the MME blend. High injection pressures (1000 bar) have higher BTE (12.33%) and better combustion characteristics (2.86%) than lower fuel injection pressures (500 bar). The concentrations of smoke (3.62%), CO (15.6%), and HC (2.8%) were reduced as injection pressure was raised, owing to the better formation of the mixture and improved spray atomization. Better results were obtained by optimizing and confirming operational parameters such as compression ratio, injection pressure, and injection time. This optimum value of 1000 bar injection pressure, injection timing of 27° bTDC, and a compression ratio of 18: 1 is utilized as the operating parameter values in the subsequent experiments to improve performance and decrease emissions while utilizing MME biodiesel blends in a CRDI engine.