Comparative Analysis on the Characteristics of a Palm Biodiesel–Diesel Blend–Powered Compression Ignition Engine Using Novel Dimensionless Index

<div>In this study, a Kirloskar TV1 compression ignition engine is put to test using diesel, palm biodiesel (B100), and palm biodiesel–diesel blend (B40D60). Among the tested fuels, engine performance at 75% loading condition with reference fuel diesel showed the highest brake thermal efficiency, brake specific energy consumption, and exhaust gas temperature at 27.78%, 12.96 MJ/kWh, and 335.88°C, respectively. While B100 and B40D60 were observed to give a lower value for the same parameters due to their inferior physiochemical properties. In terms of combustion pressure, mean gas temperature, rate of heat release, and rate of pressure rise, the values observed with B40D60 at 67.39 bar, 1397.76 K, 68.83 J/CAD, and 4.34 bar/CAD, correspondingly are better than B100 due to the presence of diesel. Yet for the same combustion parameters, the values for both the aforementioned fuels are still lower than the results seen with pure diesel fueling. Owing to higher cetane number in comparison to diesel for B100 and B40D60 resulted in a lower ignition delay value of 8 and 10, respectively. However, an inverse trend was recorded for combustion duration, where diesel attained the shortened duration of 35 CAD in comparison to B40D60 and B100. A novel benchmark known as Rationalized Engine Characteristic Quality Index was developed, which considers various parametric indicators. The dimensionless index score for diesel was observed to be 0.779, which is higher than B100 and B40D60 at 0.754 and 0.756, respectively. It can be attributed to better physiochemical properties and engine performance characteristics when using petroleum diesel.</div>