A Critical Review: Cold and Hot Exhaust Gas Recirculation on Diesel Engine

Today most of the transport vehicles in countries like India where cost effective is the predominant criteria utilize diesel engines rather than petrol engines. From past 5 years usage of diesel engines was rapid which can be addressed from the sales report of many automobile companies. The reason behind this could be cost of diesel fuel and efficiency of the diesel engine when compared to petrol engine. One of the main problems associated with diesel engine is the formation of high levels of NOx, which is a temperature-dependent phenomenon. In order to reduce NOx emissions from the engine, it is necessary to keep peak combustion temperatures under control. This paper aims at the critical review on the effect of Exhaust Gas Re-circulation (EGR) both cold and hot, on the exhaust gas temperatures, NOx emissions, efficiency etc. The exhaust gas temperature, Nox and hydrocarbon emissions, and efficiency were compared for different percentages of hot and cold EGR for diesel. The EGR system was a very effective way for reducing NOx emission from a diesel engine, particularly at the high load of engine operation condition.