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In the present study, the effects of late injection timings and EGR rates on combustion, performance and emission characteristics were evaluated in a single cylinder diesel engine that utilizes oil extracted from waste HDPE which was blended with diesel at 30% by vol. (called as D70H30 blend). The experiments were conducted by delaying the injection timing viz., 23°bTDC, 18°bTDC, and 13°bTDC at various bmep. Later the effects of increasing EGR rates viz., 0%, 10% and 20% were studied at late injection timings at peak load condition. The results reveal that the peak cylinder pressure decreases and combustion duration gets shorter with delayed injection timing. For the same SoI timing escalating the EGR rates reduced the mean gas temperature which is reflected in lower HRR peaks. The BTE of the engine deteriorated by 4.6% when the injection timing is retarded from 23°bTDC to 13°bTDC and 3.2% when the EGR rate was escalated from 0% to 20% at peak load. NOx emission significantly decreased by 80% with retarded injection timing and further decreased with the application of EGR. On the other hand, smoke emission aggravated by 22% with retarded injection timing and 24.5% with maximum EGR addition. The HC and CO emissions followed the same trend of smoke emission. It can be concluded that, utilizing 30% waste HDPE oil blend with minimal modification like retarding injection timing and low EGR rates was beneficial in effectively reducing NOx emission with a slight drop in performance.

Energy recovery and utilization from waste presents an attractive alternative solution to compensate fossil fuel demands and reduces the risk of environmental hazards. The present study aims to investigate, the effect of increasing anisole fraction in the biodiesel extracted from waste cooking oil in a diesel engine. Tests were performed by blending anisole with waste cooking oil methyl ester up to 30% vol. and the results were compared with baseline diesel and biodiesel operation. The results reveal that, increasing the anisole content in biodiesel prolongs the ignition delay period. The in-cylinder pressure and heat release rate increase with higher anisole fraction. Among the test fuels, W90A10 blend shown 1.6% better BTE than biodiesel. The NOx emission was lowest when the engine is operated with W90A10 blend, at peak load, it decreased by 17% and 11% against diesel and biodiesel operation. The smoke opacity for neat biodiesel was highest and the addition of anisole suppressed the soot formation tendency of the biodiesel significantly. HC and CO emissions are generally high when the engine is operated with biodiesel. Blending anisole with biodiesel had a positive effect on both HC and CO emissions. From the findings, it is concluded that waste cooking oil methyl ester blended with 10% by vol. of anisole can be effectively utilized in diesel engine applications with lower emissions.

The objective of this investigation was to improve the performance of a diesel engine by adding oxygenated fuel additives of known percentages. The fuel additives di-methoxy-methane (DMM) and di-methoxy-propane (DMP) were separately blended with diesel fuel in proportions of 1 ml, 3 ml and 5 ml. The experimental study was carried out on a single cylinder DI diesel engine. The result showed an appreciable reduction of emissions such as smoke density, particulate matter and marginal increase in the performance when compared with normal diesel run. The same engine was employed with diesel particulate trap (DPT) in the exhaust pipe to study its influence on the emission analysis.