Faculty Publications
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Item 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 LtdItem 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 LtdItem 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 LtdItem 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 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