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Author: search.filters.author.Kumar, G.N.Subject: search.filters.subject.Emission control

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    Experimental Studies on the Effect of Varying Rates of Part-Cooled EGR in High Pressure Loop on an MPFI Engine Under Variable Speed Operation
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Oommen, L.P.; Kumar, G.N.
    Researches in automobile sector around the globe are focused on meeting the currently proposed emission norms. Exhaust gas recirculation is one pre-treatment technique that has been found effective in enhancing the combustion and emission characteristics of IC engines and regulating the emission of nitrogen oxides. The present work analyses the effect produced by different rates of partially cooled EGR in a high pressure loop on a multi-cylinder MPFI gasoline engine. Three flow rates of EGR—12%, 18% and 24%—have been studied, and the impact produced on thermal efficiency, specific fuel consumption and emission of macropollutants of the test engine has been analysed under variable speed operation in comparison with normal operation of the engine without recirculation. The temperature of recirculated exhaust gas is so maintained as not to have a negative influence on the fuel consumption characteristics. A reduction in specific fuel consumption is observed which results in a marginal improvement of brake thermal efficiency alongside the advantage obtained in the emissions of the engine. The study proves that the advantages of EGR addition are limited to around 18% above to which the cyclic variations and misfires become predominant, deteriorating the performance and emissions of the test engine. © 2021, Springer Nature Singapore Pte Ltd.
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    Experimental studies on the impact of part-cooled high-pressure loop EGR on the combustion and emission characteristics of liquefied petroleum gas
    (Springer Science and Business Media B.V., 2020) Oommen, L.P.; Kumar, G.N.
    Liquefied petroleum gas is preferred and adopted in automotive engines because of its efficient burning and cleaner emission characteristics. Since LPG contains less carbon molecules and higher carbon to hydrogen ratios than gasoline or diesel, it has a much higher emission reduction potential both in the cases of regulated and non-regulated emissions. A major disadvantage of deploying LPG widely is the amount of NOx generation owing to the higher temperatures developed in the combustion chamber. In this study, part-cooled EGR is applied in varying rates (12%, 18%, 24%) in order to analyze the effects produced in the performance and emission characteristics of a multicylinder MPFI engine fuelled by 100% LPG at four different loading conditions and four different operating speeds. It can be observed that the application of an optimum rate of cooled EGR reduces the NOx emissions drastically even though at the expense of hydrocarbon emissions. The fuel consumption of the test engine is reduced up to 12.28% with the application of 18% percentage of part-cooled EGR. It can be inferred from the experimental studies that 18% part-cooled EGR is the optimum flow rate of recirculation which is most effective during the part load operation of the engine (50–75%) and at higher engine speeds. However, the emission of oxides of nitrogen reduced by 7.8% at 24% recirculation. The statistical analysis of combustion shows a reduction in combustion stability with increased flow of recirculation. © 2020, Akadémiai Kiadó, Budapest, Hungary.