Faculty Publications
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Item 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.Item Consequences of ignition timing on a hydrogen-fueled engine at various equivalence ratio(Taylor and Francis Ltd., 2022) Pandey, J.K.; Gottigere Narayanappa, K.The energy crisis in the transportation sector directs researchers to look for renewable alternative energy sources. Among all available, hydrogen is one of the prominent contenders that can be renewed and available on a large scale and is carbon-free. The study suggests hydrogen is a better fuel for SI engines than CI engines. However, its feasibility still needs to be investigated. In the present experimental study, a hydrogen-fueled SI engine is tested for various equivalence ratios (ϕ) and ignition timing (IT) at a compression ratio (CR) of 14:1. The outcomes show that the brake thermal efficiency (BTE) increases by 1.07% with increasing ϕ, while a slightly retarded IT exhibits the best figure. There is an average 1.42% increase per ϕ from gasoline noticed at ϕ 0.6, which increased to 2.12% at ϕ 0.8. The cylinder pressure and net heat release rate improve and advance with retarding IT and increasing ϕ. The flame development period (CA10) continuously reduces with increasing ϕ by an average 1.93%/ϕ change and retarding IT by 2.17%/2°CA ignition retard, due to increased mass of hydrogen and increased cylinder temperature. While flame propagation period (CA10-90) reduces with increasing ϕ and reduces to a minimum with retarding IT and then increase. The maximum cylinder temperature (Tmax) and exhaust gas temperature (EGT) increase with increasing ϕ by 3.28% and 3.62%, respectively, while Tmax reduces with retarding IT, resulting in a reduction in NOx emission. The EGT increases with retarding IT. The NOx emissions increase with ϕ by an average of 4.72%; however, at higher ϕ = 0.8, the NOx emissions are 2.51% lower than gasoline for most of the retarded IT. At a retarded IT, hydrogen performs similarly to gasoline at moderate NOx emissions. The high CR helps reduce volumetric losses reflected in BTE, found above gasoline despite less fuel energy supplied than gasoline. Although NOx emissions are controlled by retarding IT, an efficiently controlling IT resulted in a severe drop in BTE. © 2022 Taylor & Francis Group, LLC.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 Study of performance, combustion, and NOx emission behavior of an SI engine fuelled with ammonia/hydrogen blends at various compression ratio(Elsevier Ltd, 2022) Dinesh, M.H.; Pandey, J.K.; Kumar, G.N.In the present paper, an experimental investigation has been performed under variable CR and 1400&1800RPM speed at a fixed spark timing of 24ºCA BTDC under wide-open throttle conditions. The hydrogen blending is performed based on energy fractions from 5% to 21% of the total fuel energy. With increasing compression ratio (CR), the flame development gets faster, and the flame propagation speed improves, leading to a short combustion period. Similarly, increasing hydrogen fraction improves combustion, resulting in a rapid rise in pressure and temperature. Despite a 13.64% decrease in volumetric efficiency from 5% to 21% hydrogen fraction at 1400 and 1800 RPM, BP and BTE increased by 16.89% and 33%, respectively. The slow-burning properties of NH3 extend the combustion period, resulting in a long-delayed burning period. As a result, the temperature of the low-hydrogen fraction of the exhaust gas is higher. As the hydrogen fraction and CR increase, this effect decreases, resulting in lower EGT. The hydrogen addition increases the peak temperature; therefore, NOx increases continuously with increasing hydrogen despite reducing ammonia. Ammonia is a key element used to reduce NOx from vehicles. A practical solution for controlling the NOx due to the ammonia/hydrogen blend is selective catalytic reduction (SCR). © 2022 Hydrogen Energy Publications LLCItem Studying the effects of manifold pressure boosting and EGR on combustion and NOx emission of hydrogen-fueled SI engine(SAGE Publications Ltd, 2023) Pandey, J.K.; Gn, K.Aiming to the global energy insecurity due to extensive dependence on fossil fuels, hydrogen is supposed to provide relief by researchers. However, employed to combustion engines, this green fuel leaves hazardous NOx and limits output due to low volumetric energy content. Hence, improving operating parameters like compression ratio and manifold pressure, and NOx mitigating technique like EGR may prove a boon. Therefore, in the present study, combustion and NOx emission behavior of the SI-engine is studied under variable manifold air pressure (MAP) (up to 130 kPa) and EGR (up to 15%) at compression ratio 14:1. The outcomes shows the flame development increased by 1.24%, while flame propagation is increased by 1.63% by MAP boosting due to increased air and fuel supply. Cylinder pressure and heat-release rate (HRR) are also surged due to the increased fuel supply to maintain excess-air ratio (λ). However, peak cylinder pressure is retarded due to elongated combustion. The exhaust gas temperature (EGT) is increased by 19.4%, while elevated Tmax is observed to shoot up NOx by 40%. Combustion in improved at low EGR due to reduced λ, and also the specific NOx. At higher EGR rate deteriorated combustion due to increased heterogeneity by high dilution, increasing combustion duration, cooling losses and reducing cylinder pressure, Tmax and EGT. A 9.33% and 5.67% increase in CA10 and CA10–90 respectively is observed for 130 kPa at 15% EGR than no EGR. The rapid reduction in oxygen and higher heterogeneity reducing residence time, resulted in rapid drop (33% at N/A to 42.68% at 130 kPa for 15% EGR) in NOx by EGR. The coefficient variation is reduced by boosting MAP but increased severely at higher EGR, which restricts operating EGR rate. © IMechE 2023.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 Ltd