Faculty Publications
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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 Consequences of varying compression ratio and ignition timing on engine fueled with E-MEBANOL(SAGE Publications Ltd, 2023) Pandey, J.K.; Dinesh, M.H.; Gn, K.Alcohols are oxygenated renewable fuels responsible for low carbon emission and high H/C ratio. In the present study, a blend of methanol, ethanol, and n-butanol in equal proportion by volume (E-MEBANOL) is tested as a sustainable fuel for SI engines under variable compression ratio (CR) and ignition timing (SOI). The performance of the engine is found to improve by increasing CR as well as advancing the SOI, as the brake power (BP), brake thermal efficiency (BTE), and volumetric efficiency are found to increase by increasing CR to 15 from 11 at an advanced SOI of 24°CA before top dead center (BTDC) from 16°CA BTDC by 17.54%, 17.47%, and 10.53% respectively. Similarly, combustion is also enhanced with increasing CR and advancing SOI as the peak cylinder pressure (Pmax), and maximum net heat release rate (NHRmax) are found to increase by 60% and 27.64%, respectively, while positions of these peaks are advanced by 17°CA and 18°CA respectively by increasing CR from 11 to 15 and SOI advanced to 24°CA BTDC. The flame development period (CA10) increases with advancing SOI and decreases with increasing CR, while the flame development period (CA10-90) and total combustion duration decrease with both increasing CR and advancing SOI. The CO & HC emissions improve with increasing CR and advancing SOI, while NOx increases drastically, but EGT decreases continuously. © IMechE 2022.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