Calibration of idling characteristics for Lemon Peel Oil using Central Composite Design in light commercial vehicle diesel engine

[Display omitted] •Systematic calibration of engine idling is performed for LPO biofuel.•CCD and RSM technique is used to calibrate the engine idling condition for diesel and LPO.•LPO improves combustion quality, reduces CO & Smoke with minor surge in CO2, NOx.•Lower calorific value slightly reduces engine performance and HC rises significantly.•LPO-diesel blend is a vital key to overcome drawbacks caused by idling. Lemon Peel Oil is a clean and sustainable biofuel that has shown promising results under varying driving conditions. Growing vehicle density globally makes road congestions a common sight where the engines operate under idling conditions accounting for massive fuel wastage and severe emissions. However, considering the frequent occurrence of idling and the damage caused by it, the need to calibrate engines to utilise Lemon Peel Oil under idling conditions for addressing the issues of fuel shortage and pollution is observed. Hence, this work utilises a systematic experimental approach to analyse the potential of a 20% (vol/vol) blend of Lemon Peel Oil in diesel and compares it with conventional diesel for idling conditions. The systematic experimentation is determined using the Response Surface Methodology coupled with Central Composite Design on a Common Rail Direct Injection Engine Setup. The potential of the biofuel blend is analysed by mathematical modelling of various tests conducted. At optimal idling calibrations, 42.1% drop in smoke emissions and 16% reduction in Carbon Monoxide with an increase of 5.25% in Carbon Dioxide is reported. The slightly reduced heating value of the fuel caused a 10.18% reduction in thermal efficiency and a 21.24% increase in Specific Fuel Consumption. The 2.43% increase in peak pressure and the 4.6% increase in Heat Release Rate further suggests this biofuel blend possesses superior combustion characteristics and is a cleaner fuel. Hence, the potential of Lemon Peel Oil with optimized engine parameters is determined for the idling condition.