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The effect of early post injection in diesel engine was studied with respect to engine out emissions and torque output. Initial tests indicated that there is significant reduction of soot for same NOx or with reduced NOx due to early Post Injection (POI) in traditional high speed diesel engine depending on various operating conditions. Further studies indicated that varying the post injection quantity and timing improved engine out NOx and soot emissions significantly and that the degree of this influence depends on speed and load of the engine. Additional investigations like study of heat release curve and air by fuel ratio were done to understand this effect completely.

With newer emission norms getting introduced, OEMs are struggling hard to achieve those norms. This is because selection of appropriate technology for stringent emission norms has to be ensured in order to control higher costs and also to control adverse affect on fuel consumption. This paper briefs about the real life experience in developing Euro 4 emissions on a Sports Utility Vehicle (SUV) fitted with 2.2 liter CRDe engine. The base vehicle used is BSIII emission complaint. Efforts were made to optimize the overall emission system without use of any particle trapping device in the exhaust and with conventional air intake system. Steady and transient operating speeds of the driving cycle were optimized through common rail technology. Maximum benefits from common rail technology were captured which also were assisted by efficient Exhaust Gas Recirculation (EGR) cooling and intercooling. At the end different after treatment options were evaluated to arrive at optimum use of catalyst.