Faculty Publications
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Item 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.Item 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.Item Experimental studies on the influence of axial and radial fields of sintered neo-delta magnets in reforming the energy utilization combustion and emission properties of a hydrocarbon fuel(Taylor and Francis Ltd., 2024) Oommen, L.P.; Kumar, G.N.Permanent magnets based on rare earth components have been increasingly finding their applications in modern technologies. Although the magnetic properties tend to deteriorate rapidly at temperatures in excess of 150ºC, sintered NdFeB magnets can be employed in reforming the physical and combustion properties of hydrocarbon fuels. In the present investigation, two different magnetization patterns of high-grade NdFeB magnets are applied in varying intensities on a multicylinder MPFI engine fueled by gasoline and the alteration in combustion and emission properties of the fuel are studied. The magnetic field restructures the hydrocarbon molecules and causes the pseudo clusters to break away thus reducing the inherent viscosity and enhancing the association of hydrocarbon molecules with the oxidizer. The effectiveness of two different magnetization patterns of sintered NdFeB magnetic material in reforming the combustion characteristics is studied and compared. The study shows a maximum increase of 9.2% in power output and 7.74% in thermal efficiency of the test engine along with a significant reduction in the generation of toxic emissions that are the byproducts of combustion. The study also concludes that radial magnetic fields are more effective in conditioning the fuel and reducing the emission of CO, HC, and NOx by 8.57%, 5.52%, and 1.25% compared to the same intensity fields under axial magnetization. The combustion behavior of gasoline is studied under both field patterns. The statistical analysis of mean effective pressures through radar plots is conclusive of the reduction in cycle by cycle variations under magnetic field-assisted combustion. Abbreviations: NdFeB:Neodymium Iron Boron permanent magnet; SmCo:Samarium Cobalt permanent magnet; MPFI:Multipoint Port Fuel injection; BP:Brake Power; BTE:Brake Thermal Efficiency; BSFC:Brake Specific Fuel Consumption; NHRR:Net Heat Release Rate; IMEP:Indicated Mean Effective Pressure; COV:Coefficient of Variation; CO:Carbon Monoxide; CO2:Carbon dioxide; HC: hydrocarbon; NOxOxides of Nitrogen. © 2020 Taylor & Francis Group, LLC.