Emission Reduction and Performance Enhancement of CI Engine Propelled by Neem Biodiesel-Neem Oil-Decanol-Diesel Blends at High Injection Pressure

Diesel emissions have resulted in air pollution, which is harmful to the sustaining of life. The concerns of energy security and poor air quality have propelled researchers to seek alternate and environment-friendly fuels for the transport sector, keeping diesel engines at the core. Thus, a quaternary blend (diesel-biodiesel-vegetable oil-alcohol) proves to be a promising key to address the above problems. This experimental work focuses aims on investigating the performance and emissions of a diesel engine powered with quaternary blends by changing the fuel injection pressure. The quaternary blend comprised of diesel, neem biodiesel, pure neem oil, and decanol was used to prepare quaternary blends of varied volumetric proportions. This study involves the testing of quaternary blends at varied fuel injection pressure (IP) ranging from 400–500 bar. The engine load varied from 10 Nm to 20 Nm, and the shaft speed was constant at 2000 rpm. It was evident from the outcomes that the least DBODec45 resulted in minimum carbon monoxide (CO) and un-burnt hydrocarbon (UHC) emissions, which were obtained to be 83.33% and 54.5% less than diesel at 500 bar and at a load of 10 Nm and 20 Nm, respectively. Moreover, the blend containing 45% of decanol led to the lowest NOx and smoke concentrations. The lowest brake-specific fuel consumption (BSFC) was achieved at 500 bar and 20 Nm for the same blend and was found to be 3.22% higher than diesel. Moreover, at the same IP and load, DBODec45 led to highest BTE, which was 3.26% lower than pure diesel.