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The extents of pre combustion reaction and cumulative pre combustion energy release have been computed for various operating conditions in a single cylinder variable compression ratio research engine. Exhaust emission levels of CO and HC are measured by gas chromatography. The mean turbulent flame propagation velocity is estimated from a thermodynamic analysis of the engine cylinder pressure trace. The effect of pre combustion energy release on the flame velocity and the exhaust emissions of CO and HC has been discussed. It is found that the pre combustion energy release may account for as much as 20% of the heat in the fuel in the case of reactive fuels of relatively low octane numbers. In general, increased pre combustion reactivity is found to decrease CO and HC emission levels. However, its effect on the mean engine flame velocity does not appear to be pronounced.; The extents of pre-combustion reaction and cumulative pre-combustion energy release have been computed for various operating conditions in a single cylinder variable compression ratio research engine. Exhaust emission levels of CO and HC are measured by gas chromatography. The mean turbulent flame propagation velocity is estimated from a thermodynamic analysis of the engine cylinder pressure trace. The effect of pre-combustion energy release on the flame velocity and the exhaust emissions of CO and HC has been discussed. It is found that the pre-combustion energy release may account for as much as 20% of the heat in the fuel in the case of reactive fuels of relatively low octane numbers. In general, increased pre-combustion reactivity is found to decrease CO and HC emission levels. However, its effect on the mean engine flame velocity does not appear to be pronounced.
(Pre combustion energy release and its effect on flame propagation and exhaust emissions in a spark ignition engine) Samaga, B.S.; Murthy, B.S.
1977
The chemical reactions leading to the destruction of NO and CO in the engine combustion gases are temperature dependent and it has been observed that they change over from 'shifting' equilibrium to 'frozen' equilibrium as the temperature drops during the expansion phase. Application of reaction rate theories to the prediction of exhaust emissions is complex and can at best be an approximation owing to uncertainties of the engine combustion reaction mechanism, the assumed rate constants and the estimated combustion temperatures. An attempt was made to correlate the computed equilibrium concentrations during the expansion phase to the measured emission levels of NO and CO to estimate the temperatures at which nonequilibrium effects become apparent. Comparison of the measured emission levels from a single cylinder spark ignition engine with the computed equilibrium concentrations for several engine operating conditions has shown that the concentration of NO freezes near its peak equilibrium value, whereas the destruction of CO continues during the subsequent expansion phase until the temperature has dropped to an effective 'frozen equilibrium temperature' at which the computed equilibrium CO corresponds to the measured level in the exhaust. This temperature is dependent on the time rate of expansion and was determined to be 1250°K at 600 rpm and 1300°K at 900 rpm for the steady state operating conditions considered in the present series of tests.; An attempt has been made to correlate the computed equilibrium concentrations during the expansion phase to the measured emission levels of NO and CO to estimate the temperatures at which nonequilibrium effects become apparent. Comparison of the measured emission levels from a single cylinder spark ignition engine with the computed equilibrium concentrations for several engine operating conditions has shown that the concentration of NO freezes near its peak equilibrium value, whereas the destruction of CO continues during the subsequent expansion phase until the temperature has fallen down to an effective 'frozen-equilibrium temperature' at which the computed equilibrium CO corresponds to the measured level in the exhaust.
(Exhaust emission characteristics correlated to a chemically equilibrating gaseous system in an SI engine) Samaga, B.S.
1976
6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends
(2009) Godiganur, S.; Suryanarayana Murthy, C.H.; Reddy, R.P.
Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel. © 2008 Elsevier Ltd. All rights reserved.
Influence of low-temperature combustion and dimethyl ether-diesel blends on performance, combustion, and emission characteristics of common rail diesel engine: a CFD study
(Springer Verlag service@springer.de, 2017) Lamani, V.T.; Yadav, A.K.; Gottekere Narayanappa, K.G.
Due to presence of more oxygen, absence of carbon-carbon (C-C) bond in chemical structure, and high cetane number of dimethyl ether (DME), pollution from DME operated engine is less compared to diesel engine. Hence, the DME can be a promising alternative fuel for diesel engine. The present study emphasizes the effect of various exhaust gas recirculation (EGR) rates (0–20%) and DME/Diesel blends (0–20%) on combustion characteristics and exhaust emissions of common rail direct injection (CRDI) engine using three-dimensional computational fluid dynamics (CFD) simulation. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to carry out combustion analysis, and k-?-f model is employed for turbulence modeling. Results show that in-cylinder pressure marginally decreases with employing EGR compared to without EGR case. As EGR rate increases, nitrogen oxide (NO) formation decreases, whereas soot increases marginally. Due to better combustion characteristics of DME, indicated thermal efficiency (ITE) increases with the increases in DME/diesel blend ratio. Adverse effect of EGR on efficiency for blends is less compared to neat diesel, because the anoxygenated region created due to EGR is compensated by extra oxygen present in DME. The trade-off among NO, soot, carbon monoxide (CO) formation, and efficiency is studied by normalizing the parameters. Optimum operating condition is found at 10% EGR rate and 20% DME/diesel blend. The maximum indicated thermal efficiency was observed for DME/diesel ratio of 20% in the present range of study. Obtained results are validated with published experimental data and found good agreement. © 2017, Springer-Verlag Berlin Heidelberg.
Performance, emission, and combustion characteristics of twin-cylinder common rail diesel engine fuelled with butanol-diesel blends
(Springer Verlag service@springer.de, 2017) Lamani, V.T.; Yadav, A.K.; Gottekere, K.N.
Nitrogen oxides and smoke are the substantial emissions for the diesel engines. Fuels comprising high-level oxygen content can have low smoke emission due to better oxidation of soot. The objective of the paper is to assess the potential to employ oxygenated fuel, i.e., n-butanol and its blends with the neat diesel from 0 to 30% by volume. The experimental and computational fluid dynamic (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol-diesel blends for various injection timings (9°, 12°, 15°, and 18°) using modern twin-cylinder, four-stroke, common rail direct injection (CRDI) engine. Experimental results reveal the increase in brake thermal efficiency (BTE) by ~ 4.5, 6, and 8% for butanol-diesel blends of 10% (Bu10), 20% (Bu20), and 30% (Bu30), respectively, compared to neat diesel (Bu0). Maximum BTE for Bu0 is 38.4%, which is obtained at 12° BTDC; however, for Bu10, Bu20 and Bu30 are 40.19, 40.9, and 41.7%, which are obtained at 15° BTDC, respectively. Higher flame speed of n-butanol-diesel blends burn a large amount of fuel in the premixed phase, which improves the combustion as well as emission characteristics. CFD and experimental results are compared and validated for all fuel blends for in-cylinder pressure and nitrogen oxides (NOx), and found to be in good agreement. Both experimental and simulation results witnessed in reduction of smoke opacity, NOx, and carbon monoxide emissions with the increasing n-butanol percentage in diesel fuel. © 2017, Springer-Verlag GmbH Germany.
Effect of fuel injection strategies and EGR on biodiesel blend in a CRDI engine
(Elsevier Ltd, 2019) Bhowmick, P.; Jeevanantham, A.K.; Bragadeshwaran, B.; Kasianantham, K.; Arumuga Perumal, D.A.; Viswanathan, V.; Vora, K.C.; Jain, A.
Biodiesel appears as a replenishable and sustainable energy source and can be used a direct replacement to petro-diesel without any major transformations in ongoing diesel engines. This work concentrates on production of Calophyllum Inophyllum biodiesel (CIB) and preparing 10% blend (CIB10) sample to investigate the effects of varying the injection strategies and exhaust gas recirculation (EGR) in common-rail direct injection engine. The experimental results shows that 10% of pilot fuel and 90% main injection strategy (B10@P10-M90) is superior among all others injection strategies with respect to pure diesel. B10@P10-M90 fuel injection strategy produces the maximum efficiency of 35.8% and lowest fuel consumption of 0.25 kg/kWh compared to all the injection strategies. The carbon monoxide (CO) and hydrocarbon (HC) emissions are also found to be quite low compared to all the other test samples including pure diesel. However B10@P10-M90 results in higher average oxides of nitrogen (NOx) emission which is 18.9% higher in contrast to conventional diesel at full load condition. With the implementation of 10% and 20% EGR with B10@P10-M90, the average NOx emissions decreased by 14.4% and 27.6% respectively compared to B10@P10-M90 without any EGR without significant loss in the performance of the existing diesel engine. © 2019 Elsevier Ltd
Assimilative capacity approach for air pollution control in automotive engines through magnetic field-assisted combustion of hydrocarbons
(Springer Science and Business Media Deutschland GmbH, 2021) Oommen, L.P.; Gottekere Narayanappa, K.G.
Deterioration of air quality through the combustion of hydrocarbon fuels has been one of the global transboundary problems put before the research community since last five decades. According to the updated statistics, 79% of energy needs in India are met by fossil fuel combustion which results in the emission of toxic pollutants like carbon monoxide, oxides of nitrogen, and unburned hydrocarbons. Air quality has seriously been affected in many parts of India, and statistically, 13 out of 15 most polluted cities in the world lie in India. Magnetic field-assisted combustion has been proven as a reliable technology in internal combustion engines for enhancing the combustion of fuels and reduction of harmful emissions that are the byproducts of incomplete combustion of fuels. In the present work, the magnetic field-assisted combustion of a liquid-phase and a gas-phase fuel (gasoline and LPG) has been studied in a multicylinder automobile engine replicating on road driving conditions in a laboratory focusing on the levels of emissions in comparison with normal combustion of both the fuels. The experimental study concludes that the applied magnetic field positively influences combustion, resulting in reduced level of emission of toxic components irrespective of the phase of hydrocarbon fuels. It is also observed that the percentage reduction in emissions increases with increase in intensity of magnetization. The maximum reduction obtained for CO and UBHC emissions through this technique is 20.58% and 14.47%, respectively. The effectiveness of MFAC in countering air pollution from vehicular exhaust is also studied with respect to fuel phase and mode of operation. The effectiveness of MFAC is observed to be more in high-speed operation of the engine and decreases in the order CO > UBHC > NO. The obtained emission results have a cumulative significance as 45% of total air pollution in India is caused by combustion of hydrocarbons in automotive engines. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
Effect of fuel preheating on performance, emission and combustion characteristics of a diesel engine fuelled with Vateria indica methyl ester blends at various loads
(Academic Press, 2022) Kodate, S.V.; Raju, P.S.; Yadav, A.K.; Kumar, G.N.
The present study examines the preheated (95 °C) and unheated (35 °C) Vateria indica methyl ester (VIME) blends by studying the engine performance, combustion, and emission characteristics at various loads. A single-cylinder, TV1 Kirloskar direct injection diesel engine is used to carry out the tests. Biodiesel produced from Dhupa fat through the transesterification process is used as a renewable fuel in a diesel engine. In this work, diesel (B0), VIME (B100), and two binary blends (B30 and B50) are used. VIME has a higher viscosity, higher density, and lower calorific value than diesel, resulting in lesser brake thermal efficiency (BTE) and higher brake specific energy consumption (BSEC). Due to high viscosity of the biodiesel, preheating of fuel is done before injecting into cylinder. Preheating reduces the viscosity, and enhances the atomization and vaporization of fuel, resulting in improved engine performance. For a given blend of VIME biodiesel and diesel, the preheated blend has better BTE, decreased BSEC and lesser CO and HC emissions, with a slight increment in NOX emission compared to the unheated blend. The preheated B30 blend has a BTE value of 30.3% which is close to the BTE value of 30.1% of unheated diesel at 100% load condition. CO, HC, and soot emissions are decreased by 16.2%, 34.4%, and 16.5%, respectively, for preheated B100 fuel compared to unheated B100, at full load. © 2021 Elsevier Ltd
A DFT study of the adsorption behavior and sensing properties of CO gas on monolayer MoSe2 in CO2-rich environment
(Springer Science and Business Media Deutschland GmbH, 2024) Vinturaj, V.; Yadav, A.K.; Singh, R.; Garg, V.; Bhardwaj, R.; Ajith, K.M.; Pandey, S.K.
Context: Carbon monoxide, also known as the “silent killer,” is a colorless, odorless, tasteless, and non-irritable gas that, when inhaled, enters the bloodstream and lungs, binds with the hemoglobin, and blocks oxygen from reaching tissues and cells. In this work, the monolayer MoSe2-based CO gas sensors were designed using density functional theory calculation with several dopants including Al, Au, Pd, Ni, Cu, and P. Here, Cu and P were found to be the best dopants, with adsorption energies of −0.67 eV (Cu) and −0.54 eV (P) and recovery times of 1.66 s and 13.8 ms respectively. Cu conductivity for CO adsorption was found to be 2.74 times that of CO2 adsorption in the 1.0–2.26 eV range. P displayed the highest selectivity, followed by Pd and Ni. The dopants, Pd and Ni, were found suitable for building CO gas scavengers due to their high recovery times of 9.76 × 1020 s and 2.47 × 1011 s. Similarly, the adsorption of CO2 on doped monolayer MoSe2 was also investigated. In this study, it is found that monolayer MoSe2 could be employed to create high-performance CO sensors in a CO2-rich environment. Method: The electrical characteristics of all doped MoSe2 monolayers are obtained using a DFT calculation with the PBE-GGA method from the Quantum ESPRESSO package. The self-consistent field (SCF) computations were performed using a 7 × 7 × 1 k-point grid and a norm-conserving pseudo potential (NCPP) file. To determine electrical conductivity, the semi-classical version of Boltzmann transport theory, implemented in the Boltz Trap code, was used. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
A numerical study comparing the performance of a self-aspirating domestic LPG porous burner and that of a conventional LPG burner
(Elsevier Ltd, 2024) Ranjan, S.; Parthasarathy, P.; Velamati, V.
The study involves in the design of a domestic two-layer self-aspirating porous burner that operates at a thermal load of 1 kW using liquefied petroleum gas (LPG). The porous burner is intended to function within India's standard domestic regulator fuel inlet pressure of 3000 Pa. For the same thermal load, this work also provides a numerical comparison between the domestic conventional burner and the designed porous burner. For both porous and conventional burners, a full-scale 3D model is developed to calculate the flow, combustion, heat transfer to the cooking vessel, thermal efficiency, and emissions. The combustion process of both burners is numerically computed using a detailed chemical kinetic mechanism of LPG combustion, the San Diego Mechanism (SDM) with 57 species and 268 reactions are used. The porous burner is simulated using a non-thermal equilibrium condition to better calculate the heat recirculation within the porous domain. The self-aspirated porous burner has an equivalence ratio ? of 0.75 at 1 kW and an efficiency of 84.2%; conventional burner at the same load had an efficiency of 68%. 10 and 6 parts per million (ppm), respectively, are the measured CO and NOx emissions from the domestic porous burner and 660 and 80 ppm for domestic conventional burner, respectively. © 2024 Elsevier Ltd

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