Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
12 results
Search Results
Item 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.Item 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 LLCItem 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 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 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 Study of combustion and emission of a SI engine at various CR fuelled with different ratios of biobutanol/hydrogen fuel(Elsevier Ltd, 2023) Pandey, J.K.; Kumar, G.N.The global requirement is shifting to territorial independence of energy sources, and the introduction of alcohols and biofuels are the primary sectors. Recently agriculture products-based ethanol has replaced a larger portion of gasoline. Butanol is another impressive fuel in the same chain, much better than ethanol in many parameters. Butanol has certain limitations, too, such as higher latent heat and low heating value. Therefore, biobutanol/hydrogen is tested experimentally at various compression ratios (CR) in the present study. Brake thermal efficiency was not significantly changed by CR at 90% butanol, while CR is more impressive with increasing hydrogen. The flame development period was reduced by 34%, while the flame propagation phase was reduced by 29% by increasing CR to 15 and hydrogen to 25%. Peak pressure and heat release rate surged by 12.89% and 12.32% and advanced by 6°CA. The coefficient of variations is also reduced by 21% by increasing CR to 15 and hydrogen to 30%. Higher hydrogen faced combustion difficulties due to increasing stratification and heterogeneity during combustion. Unlikely to trend, Tmax (peak cylinder temperature) and NOx were continuously increased with CR and hydrogen due to increased fuel quantity and larger mass burning before TDC. However, CO and HC emissions were reduced by CR due to increased BTE (brake thermal efficiency) and reduced by hydrogen due to less HC supply. A slight increase in HC and CO was noticed for higher hydrogen due to local heterogeneity and disassociation at high temperatures. © 2023 Hydrogen Energy Publications LLC