Faculty Publications
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Item 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.Item Effect of hydrogen addition on combustion and emissions performance of a high speed spark ignited engine at idle condition(Serbian Society of Heat Transfer Engineers, 2018) Shivaprasad, K.V.; Chitragar, P.R.; Kumar, G.N.The fuel depletion and environmental pollution have pushed studies on improving the combustion and emission characteristics of internal combustion engines with several alternative fuels. Expert studies proved that hydrogen is one of the prominent energy source which has exceptional combustion qualities that can be used for improving combustion and emissions performance of gasoline-fueled spark ignition engines. This paper introduced an experiment conducted on a single cylinder high speed gasoline engine equipped with a hydrogen injection system to discover the combustion and emissions characteristics with various hydrogen gasoline blends at idle condition. For this purpose, the conventional carburetted high speed spark ignition engine was modified into an electronically controllable engine with help of electronic control unit which dedicatedly used to control the ignition timings and injection duration of gasoline fuel. © 2018 Society of Thermal Engineers of Serbia.Item Effects of hydrogen assisted combustion of EBNOL IN SI engines under variable compression ratio and ignition timing(Elsevier Ltd, 2022) Pandey, J.K.; Kumar, G.N.Alcohols are oxygenated fuels, holding a good reputation among alternatives, but single alcohol does not possess all qualities. Besides, the high latent heat and low vapor pressure limit their uses in SI engines. Hence, an energy enhancing and combustion promoting fuel helps overcome the drawbacks, among all available hydrogen fits the race most. Hence, hydrogen-assisted combustion of equivolume blend of ethanol/butanol (ENBOL) is experimentally tested under various compression ratios (CR) (11–15), ignition timing (16°CA-24°CA BTDC) for three hydrogen fractions (5%–15%) at three speeds (1400RPM-1800RPM). The experimental outcome notices an increase in brake power (BP), brake thermal efficiency (BTE), peak pressure (Pmax), heat release rate (HRRmax), and NOx emissions with increasing CR and Hydrogen addition. The combustion duration, CO, and UBHC emissions reduce while CO2 emissions reduce with hydrogen; increasing CR notices a drop in CO2 at a much advanced or much-delayed ignition. Hydrogen improves combustion but reduces volumetric efficiency; increasing CR improves it, and hydrogen effect reduces with increasing CR. BP, BTE, and CA10-90 improve with retarding ignition from 24°CA, while CA10, Pmax, and HRRmax reduce continuously. UBHC and CO emissions increase while NOx reduces with retarding ignition. The ignition timing of 20°CA at CR15 and 15% hydrogen performed better than gasoline. © 2022 Elsevier LtdItem Effects of compression and mixing ratio on NH3/H2 fueled Si engine performance, combustion stability, and emission(Elsevier Ltd, 2022) Dinesh, M.H.; Kumar, G.N.Carbon-free fuels for the worldwide decarbonization movement are ammonia and hydrogen. The experiment is conducted under WOT conditions with a constant ignition timing of 24°CA BTDC to evaluate performance, combustion stability, and emissions with varying CR (12 to 15), hydrogen energy fractions (5 to 21%), and engine speeds between 1500 and 1700 RPM. BP increased by 31.2% at 1700RPM and BTE increased by 39.0% at 1500RPM, despite a 9% decrease in volumetric efficiency at 1700RPM, from 5% hydrogen fraction at CR12 to 21% hydrogen fraction at CR15.The combustion process is sped up by the effect of hydrogen fraction and CR, causing the flame development and propagation period to shorten. NOx emission was increased significantly with hydrogen and CR, with an increase of 42.34% from 5% hydrogen at CR12 to 21% hydrogen at CR15 at 1700 RPM. Excessive NOx emissions are a drawback that can be successfully controlled by installing after treatment or exhaust gas recirculation technologies. Ammonia is another important key element used to reduce NOx emissions from vehicles because it is used in SCR. © 2022 The AuthorsItem Influence of ignition timing on performance and emission characteristics of an SI engine fueled with equi-volume blend of methanol and gasoline(Taylor and Francis Ltd., 2023) Nuthan Prasad, B.S.; Kumar, G.N.In the present investigation, experiments were conducted in wide open throttle condition (WOT) for different speed ranging from 1400 rpm to 1800 rpm at an interval of 200 on a single-cylinder four-stroke port-injected; spark-ignition engine. The engine fueled with equi-volume blend of methanol/gasoline was tested for different ignition timing and its effects on engine characteristics. The experiment results shown, retardation of ignition timing to 14⁰ BTDC exhibits excellent results compared to 24⁰ BTDC ignition timing. The results obtained show a good agreement of improvisation observed with M50 fuel in terms of BTE and BSEC at a speed of 1600 rpm when compared to gasoline fuel. The optimal ignition timing attributes to good combustion efficiency with increasing cylinder pressure and heat release rate. However, low carbon–hydrogen ratio and oxygen content in methanol aids to reduced NOx, HC, and CO emissions by 50%, 35%, and 40%, respectively. The small increase of 10% in CO2 emission is observed; this is due to retardation of ignition time, which allows the M50 fuel to absorb sufficient energy and achieve complete combustion. © 2019 Taylor & Francis Group, LLC.Item A comparative study of NOx mitigating techniques EGR and spark delay on combustion and NOx emission of ammonia/hydrogen and hydrogen fuelled SI engine(Elsevier Ltd, 2023) Pandey, J.K.; Dinesh, M.H.; Kumar, G.N.IC engines, the backbone of the transportation sector is facing energy insecurity and stringent environmental norms motivating researchers to look for alternate ways of revival. In pursuit hydrogen and its careers are seen as promising option. Aiming the same comparative-study is performed on NH3/H2 (7:3) and hydrogen under varying ignition (from −24°CA to −12°CA) and EGR rates (till 25%). Results indicate improved combustion for NH3/H2 for a small range of ignition than hydrogen, ∂P/∂θ and ∂Q/∂θ is improved before TDC and deteriorates after it. Cycle-by-cycle variations increase for a longer ignition range for NH3/H2, but NOx drops more rapidly. At −24°CA, NH3/H2 has observed a minimal gap in peak pressure, CoV and performance from hydrogen. Though a small EGR helps reduce NOx, cycle-by-cycle variations and CA90 reduce due to improved combustion for NH3/H2. ∂P/∂θ and ∂Q/∂θ improve for the same range too. However, hydrogen suffers adverse effects due to EGR that intensify with increasing EGR-rate. At higher EGR, unstable combustion and heterogeneity prevail, resulting in increased cycle-by-cycle variations and a rapid drop in peak pressure. The prolonged combustion witnesses a massive decline in NOx for both fuels; however, the gap between NH3/H2 and hydrogen entities reduces. NH3/H2 shows better efficiency than hydrogen for an efficient NOx control. However, higher fuel NOx maintains a significant difference for NH3/H2 than hydrogen. The study limits quantitative analysis of it and also NH3 emissions, which is another primary concern. © 2023 Elsevier LtdItem Experimental investigation of variable compression ratio and ignition timing effects on performance, combustion, and Nox emission of an ammonia/hydrogen-fuelled Si engine(Elsevier Ltd, 2023) Dinesh, M.H.; Kumar, G.N.In the present experimental study hydrogen-assisted ammonia combustion strategy is used in a SI engine with variable ignition timings (18ºCA bTDC to 32ºCA bTDC) and wide-open throttle conditions, CR changes (14–16) at 1400RPM and 1800RPM. This article aims to optimize ignition timing to boost efficiency and power without knocking. It has been established that ammonia/hydrogen fuels are a clean energy source capable of reducing pollution caused by undesirable emissions. The results revealed that increasing the CR from 14 to 16 increased brake power, brake thermal efficiency, NOX, cylinder pressure, and net heat release rate by 36.82%, 25.11%, 30.21%, 10.35%, and 9.53%, respectively. CA10-90 and EGT, on the other hand, are reduced. Increased speed reduces volumetric efficiency by 9.5% at 1800 RPM. In each CR, 28ºCA bTDC ignition timing and 21% hydrogen energy fraction performed well, which can be observed. Hence, the experiment results indicate hydrogen can be used as a combustion promoter, establishing a new standard for developing ammonia-fuelled engines. © 2023 Hydrogen Energy Publications LLC