EGR Combined with Particulate Trap for the Reduction of Oxides of Nitrogen and Smoke Emissions in a Small DI Diesel Engine

R. Anand, N.V. Mahalakshmi


The increase in motorized transport has led to a simultaneous increase in oxides of nitrogen (NOx) and smoke emissions. Though a wide range of reduction strategies have been explored, exhaust gas recirculation (EGR) combined with particulate trap technology has proved to be a more effective and economic choice. The effect of EGR on engine performance and emissions was studied on a single-cylinder, direct injection (DI) diesel engine run at a constant speed of 1500 rpm at various loads. The present work aims at studying the effect of hot and cool EGR on the formation of NOx. The baseline readings were determined from the experimental results obtained from an engine without EGR run at various operating conditions. This would definitely form a healthy means of evaluation of the effect of EGR on engine performance and emissions. Comparison of the findings of hot and cool EGR at full load conditions corresponds to a proportion of 15% which amounts to be the maximum allowable one, has revealed the effectiveness of cool EGR on the reduction of NOx and smoke emissions as compared to hot EGR. Hence, a suitable particulate trap with a high trapping efficiency and cost effectiveness is strongly desired before the EGR cooler to reduce the smoke emissions to meet the emission standards. The present study uses a particulate trap with a substrate made of clay material, made into spheres coated with copper and zinc oxide catalyst material. Effective reduction in NOx and smoke emissions by 63% and 42% respectively have been observed by the combination of EGR and the particulate trap. A simultaneous increase in brake specific fuel consumption by 10% as compared to baseline operation has also been observed.


EGR, metal oxide, NOx, particulate trap, smoke

Full Text: