Simultaneous Reduction of Oxides of Nitrogen and Smoke Emissions by Using EGR Combined With Particulate Trap in a DI Diesel Engine

Exhaust gas recirculation (EGR) combined with particulate trap technology has proven to reduce nitrogen oxides (NO_x) and smoke emissions simultaneously at relatively low cost compared to other reduction strategies. An experimental study was conducted on a single cylinder, direct injection (DI) diesel engine to study the effect of EGR on engine performance and emissions under constant speed of 1500 rpm at various loads. In the present work hot and cool EGR were used to control the formation of NO_x in a D.I diesel engine. The findings of both hot and cool EGR are discussed and compared at full load condition corresponding to the maximum allowable EGR proportion of 15%. It is found that cool EGR has a substantial reduction in NO_x and smoke emissions compared to hot EGR. Based on the above result it is found that suitable particulate trap which is cost effective and high trapping efficiency is needed before the EGR cooler to reduce the smoke emissions to meet the emission standards. In the present study a substrate made of clay material was used in the particulate trap. They were made into spheres and coated with copper and zinc oxide catalyst material. The results have shown that EGR combined with particulate trap simultaneously reduces the NO_x and smoke emissions by 63% and 42% respectively where as it increases brake specific fuel consumption by 10% compared to baseline mode.