An Experimental Investigation on the Efficacy of EGR on the Soot-NOX-BSFC Trade-off Characteristics of a CRDI Assisted 4-Stroke Single Cylinder Diesel Engine under Varying Injection Durations

The present work is an exploratory effort to exploit the extolled benefits of CRDI in registering significant reductions in soot with corresponding gains in fuel consumption and thermal efficiency over conventional diesel engine operation. However, such premiums have been observed at the expense of drastic increase in NOx emissions. In recognition of the NOx reduction potential that EGR possess compounded by its wide spread popularity of easy deployment and ease of operation EGR strategy was incorporated in the present work to harness the inherent benefits of CRDI operational characteristics. Subsequent observation during variable injection duration of CRDI operation yielded 97%, 95%, 89% and 93% reduction in soot at 25%, 50%, 75% and full load condition with a corresponding 9.5%, 14%, 16.5% and 28% decrease in BSFC respectively but with a penalty of a drastic 9 times, 6 times, 5 times and 7 times NOx increase respectively. Experimental tests yielded 27.4%, 26.3%, 45.5% and 40.5% NOx reduction when compared the lowest injection duration case under CRDI operation at 25%, 50%, 75% and full load conditions respectively at 30% EGR. However, EGR is very useful for decreasing NOx emission; all soot values rose up along with EGR rising.