Enhancement of idling characteristics using multi-objective approach in light-duty diesel Vehicle fuelled with orange peel biofuel

[Display omitted] •Interpretative parametric optimization of CRDi engine Idling Operation for OPO blends.•Statistical approach CCD and RSM incorporated calibration of Idling Operation.•Optimum PIT 21° bTDC, PM 24%, FIP 500 bar and 1100 rpm as an idle engine speed.•Various response regression models for diesel and OPO20 under idle mode.•Better combustion characteristics due to the inherent oxygen content in OPO. Along with an increasing demand for an alternate source of fossil fuel, rapid urbanization has increased the motor vehicle pollutant spews in a metropolis, especially in traffic congestion or cold start condition. In reference to these situations; this research is aimed at utilizing orange peel oil (OPO) as blend fuel to mineral diesel in light-duty diesel engine and asses the output characteristics for optimizing engine fuel map under idling condition. A four-factor central composite design (CCD) approach-based response surface methodology (RSM) analysis is applied to statistically relate the effect of important input variables on key engine characteristics to achieve minimum emissions without a major compromise on the power output. From the desirability report, for orange Peel Oil (20%) blended with diesel fuel (80%) (OPO20) fuel, the optimum pilot injection timing is 210 before top dead centre (bTDC), pilot mass of 24% and apt fuel injection pressure is 500 bar while maintaining 1100 rpm as idle engine speed. While tuning the OPO20 operated engine fuel map under this optimum operating condition, a notable reduction of 34% in carbon monoxide and 36.84% reduction in smoke is observed in comparison to diesel. However, the increased mean gas temperature in-turn translated into 37.65% increase in oxides of nitrogen. As a trade-off to the reduced emissions, a 15.47% decrease in the brake thermal efficiency is observed while the specific fuel consumption also increased by 29.98% in comparison to diesel operation.