Impact of 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. But when we look on the worse side of diesel engine, emissions from diesel engine are high especially NOx. So there is a need for a technique which could reduce the emissions without affecting the performance of engine. One such technique could be Exhaust gas recirculation. Present paper aims to find the impact of cold and hot EGR on emissions of diesel engine.
Diesel engine exhaust gas recirculation--a review on advanced and novel concepts
Exhaust gas recirculation (EGR) is effective to reduce nitrogen oxides (NOx) from Diesel engines because it lowers the flame temperature and the oxygen concentration of the working fluid in the combustion chamber. However, as NOx reduces, particulate matter (PM) increases, resulting from the lowered oxygen concentration. When EGR further increases, the engine operation reaches zones with higher instabilities, increased carbonaceous emissions and even power losses. In this research, the paths and limits to reduce NOx emissions from Diesel engines are briefly reviewed, and the inevitable uses of EGR are highlighted. The impact of EGR on Diesel operations is analyzed and a variety of ways to implement EGR are outlined. Thereafter, new concepts regarding EGR stream treatment and EGR hydrogen reforming are proposed.
Improvement Of Engine Performance Using Diethylene Glycol Dimethyl Ether (DGM) As Additive
This research work investigates diesel combustion and exhaust emissions with additives addition to conventional diesel fuel in a four-stroke naturally aspirated direct injection (DI) diesel engine. The additives include DGM, and liquid cerium. The results show that with the addition of DGM to diesel fuel, brake specific energy consumption (BSEC) and all diesel emissions are significantly reduced. The volumetric blending ratios of additives to diesel fuel are 0, 25, 50, 75 and 100%. All emissions including smoke emissions decrease with the increase in oxygen content in the fuel and it is noted that smoke emission completely disappeared at an oxygen content of 36 wt–%. The reason for improvement in BSEC with the addition of additives to base diesel fuel is the improvement of degree of constant volume combustion, and the reduction of the cooling loss. Engine noise and odor concentrations are remarkably reduced with diesel-additive blends. Significant improvement in BSEC and exhaust emissions is not only found at medium load condition but also at high load condition.
 Key words: Diesel engine, DGM, emissions, BSEC, and cooling loss