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

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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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    Effect of exhaust gas recirculation (EGR) on diesel engine using Simarouba glauca biodiesel blends
    (Regional Energy Resources Information Center (RERIC) enreric@ait.ac.th, 2015) Bedar, P.; Pandey, J.K.; Kumar, G.N.
    This article deals with the usage of non-edible Simarouba glauca (paradise) oil as a biodiesel for single cylinder diesel engine with application of exhaust gas recirculation (EGR) rates. Biodiesel blends B10, B20 with EGR rates of 10%, 15%, and 20% are used for different load conditions. Parameters like brake thermal efficiency (BTE), nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons (HC) and smoke opacity were evaluated from the experimental study. The results show that Simarouba glauca biodiesel usage decreases HC, CO and smoke emissions with slight increase of NOx, also an improvement in the performance was observed for B10 blend. EGR rates 10% and 15% are beneficiated in terms of performance and emission but negative trend is observed for 20% EGR rate. On the whole it is concluded that a better trade-off between NOx and other emissions is attained with simultaneous application of EGR (15%) and biodiesel blend (B10) without compromising engine performance.
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    Effect of hydrogen addition on the performance and emission parameters of an SI engine fueled with butanol blends at stoichiometric conditions
    (Elsevier Ltd, 2015) Raviteja, S.; Kumar, G.N.
    Hydrogen is considered as the best fuel due to its excellent combustion properties. But its use as a fuel is confined by its low energy density. In the present investigation an attempt has been made to utilize some of the benefits of hydrogen by using it as an additive in a butanol fueled engine. The experimental study has been carried out on a 4 stroke, single cylinder, manifold electronic fuel injected (EFI) engine mapped to run at stoichiometric conditions. Butanol blends were chosen as the base fuel due to their higher energy density compared to ethanol. A small fraction of hydrogen was injected into the air stream. The engine was run at 3000 RPM at full load condition. The performance, emission and combustion parameters are compared for four concentrations of butanol (10%, 20%, 30%, and 100% by volume of fuel) and two concentrations of hydrogen (5%, and 10% by volume of air) with gasoline. The results indicated that the efficiency of the engine improved upon hydrogen enrichment. An average of 60% reduction was observed in HC and CO emissions with 10% enrichment of hydrogen, whereas the NO emissions almost doubled itself. The combustion analysis showed reduced delay periods, shorter combustion durations, higher cylinder pressures, higher temperatures and improved combustion. © 2015 Hydrogen Energy Publications, LLC.
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    Experimental Investigation of Variations in Spark Timing using a Spark-Ignition Engine with Hydrogen-Blended Gasoline
    (Wiley-VCH Verlag info@wiley-vch.de, 2015) Shivaprasad, K.V.; Chitragar, P.R.; Kumar, G.N.
    This study describes an experiment conducted using an electronically controllable single-cylinder high-speed gasoline engine to analyze the performance and emissions characteristics of various hydrogen-gasoline blends. The experiments have been conducted for various engine speeds and spark timings at the wide open throttle position. The experimental results revealed that the engine brake thermal efficiency and brake mean effective pressure first increase and then decrease with the increase engine speed at all spark timings. The minimum amount of brake specific energy consumption was observed for 20% hydrogen addition in the total fuel blend at 3000rpm engine speed and 14°crank angle (CA) before top dead center (BTDC) spark timing. Hydrocarbon and carbon monoxide emissions were reduced with the retardation of spark timings. Nitrogen oxide emissions were continuously increased with the addition of hydrogen in the fuel blend as well as spark timing advance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Influence of spark timing on the performance and emission characteristics of gasoline–hydrogen-blended high-speed spark-ignition engine
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2017) Shivaprasad, K.V.; Chitragar, P.R.; Nayak, V.; Kumar, G.N.
    This article experimentally investigates the effect of spark timing on performance and emission characteristics of high-speed spark-ignition (SI) engine operated with different hydrogen–gasoline fuel blends. For this purpose, the conventional carbureted SI engine is modified into an electronically controllable engine, wherein an electronically controllable unit was used to control the ignition timings and injection duration of gasoline. The tests were conducted with different spark timings at the wide open throttle position and 3000 rpm engine speed. The experimental results demonstrated that brake mean effective pressure and engine brake thermal efficiency increased first and then decreased with the increase in spark advance. Peak cylinder pressure, temperature and heat release rate were increased until 20% hydrogen addition and with increased spark timings. NOx emissions were continuously increased with the increment in both spark timings and hydrogen addition, whereas hydrocarbon emissions were increased with spark timings but decreased with hydrogen addition. CO emissions were reduced with the increase in spark timing and hydrogen addition. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Impact of changing compression ratio on engine characteristics of an SI engine fueled with equi-volume blend of methanol and gasoline
    (Elsevier Ltd, 2020) Nuthan Prasad, B.S.; Pandey, J.K.; Kumar, G.N.
    In the present investigation, experiments were conducted in wide open throttle condition (WOT) for different speed ranging from 1200 rpm to 1800 rpm at an interval of 200 on a single-cylinder four-stroke variable compression ratio (VCR) SI engine. The engine fueled with equi-volume blend of methanol/gasoline fuel, while 14° BTDC ignition timing is maintained for all three different compression ratios (8, 9 & 10). Increasing the compression ratio from CR8 to CR10 for the methanol/gasoline blend has improved combustion efficiency by increasing the peak pressure and net heat release value by 27.5% and 30% respectively at a speed of 1600 rpm. The performance results show a good agreement of improvisation of 25% increase in BTE, and BSFC reduction by 19% at compression ratio 10:1. At higher compression ratio 10:1, there was a significant decrease observed in CO and HC by 30–40%, and the same trend is observed at all speeds; however, NOx emission increased with the increasing CR. © 2019 Elsevier 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.
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    Effect of hydrogen enrichment on performance, combustion, and emission of a methanol fueled SI engine
    (Elsevier Ltd, 2021) Nuthan Prasad, B.S.; Pandey, J.K.; Kumar, G.N.
    The study of potentially high rated alternative fuel (Methanol) for the IC engines is an exciting topic in the recent research advancement. However, the study of combination of methanol and hydrogen is considered to address both economic and environmental needs. Hydrogen with best combustion characteristics will compensate for the drawbacks of methanol as a fuel. In the present investigation hydrogen enrichment to methanol has shown a significant enhancement in performance and combustion; the overall emission has reduced substantially. The experiments for a different set of trials, including hydrogen enrichment ranging between 5% and 20% with 2.5% increment, the engine is operated with wide-open throttle (WOT) condition for different speeds. The increase in enrichment of hydrogen has shown a rise in BTE, BP, and a reduced BSEC value. The percentage increase in BTE is between 20 and 30%, and an increase in hydrogen beyond 12.5% would affect the volumetric efficiency, and thus performance declines after that. The exhaust emissions have a huge impact on hydrogen enrichment; CO, HC, and CO2 emission are reduced by 30–40%; however, an increase in cylinder temperature due to rapid combustion slightly increases the NOx emission. Thus hydrogen enriched methanol operating at higher compression ratio can improve the overall engine characteristics significantly. © 2021 Hydrogen Energy Publications LLC
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    Effect of variable compression ratio and equivalence ratio on performance, combustion and emission of hydrogen port injection SI engine
    (Elsevier Ltd, 2022) Pandey, J.K.; Kumar, G.N.
    The present study includes an experimental investigation of the performance, combustion, and emission parameters of a hydrogen port fueled SI engine under wide-open throttle. The compression ratio (CR) is varied from 10 to 15, equivalence ratio (φ) from 0.4 to 1.0, and speed from 1400RPM to 1800RPM. The ignition timing is maintained at 20° before the top dead center. The brake thermal efficiency increases by nearly 10% from CR10 to CR15, and it also increased by 13.7% by changing φ from 0.4 to 0.9. Similarly, BP increases in the same fashion. The combustion enhances with an increase in peak pressure by increasing CR from 10 to 15 and φ from 0.4 to 0.9; however, φ 1.0 exhibits a negative trend. However, the NOX emission increases continuously with CR and φ, and so as the exhaust gas temperature. The carbon-based emissions are negligible, and volumetric efficiency decreases with φ and increases with CR. © 2021 Elsevier Ltd
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    Effect of parallel LPG fuelling in a methanol fuelled SI engine under variable compression ratio
    (Elsevier Ltd, 2022) Dinesh, M.H.; Pandey, J.K.; Kumar, G.N.
    In the present experimental study, five LPG fractions from 25% to 45% based on total energy are tested in a methanol fuelled SI engine at compression ratios (CR) varying from 12 to 15. Results are affirmative towards methanol/LPG dual fuel. The brake power, brake thermal efficiency, and volumetric efficiency are found to increase by 51%, 21.2%, and 13% respectively by changing from 25% LPG fraction at CR12 to 45% LPG fraction at CR15. The flame development period is found to decrease with CR and LPG, while the flame propagation period and total combustion duration are found to decrease with CR but increase with LPG. The maximum cylinder pressure and net heat release rate are found to increase by 101% and 27.8% respectively and advanced. CO emissions are found to decrease with CR while increase with LPG fraction. HC is found to decrease with LPG as well as CR. CO2 emissions are found to increase continuously with increasing LPG fractions and CR. The NOx emissions are also found to increase explicitly with LPG and CR, a net 209% increase in it is found 25% LPG at CR 12–45% LPG at CR15. © 2021 Elsevier Ltd