Influence of retarded injection timing on thermal performance and emission characteristics of a diesel engine fuelled with an optimized pyrolytic blend

The enormous rise in plastic waste leads to severe environmental issues and complete removal is a quiet challenge. The entire world focuses on finding new alternate for traditional conventional fuel. The waste low-density polyethylene is chosen as feedstock for the preparation of fuel from thermo-catalytic pyrolysis, considering the silica–alumina catalyst at a reaction temperature of 500 °C. From our previous study, the lower blends of waste low-density polyethylene exhibit a similar performance to diesel. However, brake thermal efficiency and oxides of nitrogen are not encouraging. Further improving combustion behaviour, the present research is carried out at different injection timings. The investigation is carried on standard injection timing of 23°bTDC and three retarded injection timings, namely, 21°bTDC, 19°bTDC and 17°bTDC. Retarded injection timing exhibits higher performance and lower unburned hydrocarbon, oxides of nitrogen and carbon monoxide emissions. However, smoke emission is increased due to the reduced heat release at all the considered test parameters. The result divulges that reduced performance and increased smoke at 17°bTDC due to the lack of burning rate. The combustion behaviour of 20% waste low-density polyethylene by volume at 19°bTDC is similar to that of diesel at 23°bTDC. Hence, the injection timing of 19°bTDC is preferred as an optimized condition for the test fuel 20% waste low-density polyethylene by volume.