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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
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.
Source apportionment studies on particulate matter (PM10 and PM2.5) in ambient air of urban Mangalore, India
(Academic Press, 2018) Kalaiarasan, G.; Mohan Balakrishnan, R.M.; Sethunath, N.A.; Manoharan, S.
Particulate matter (PM10 and PM2.5) samples were collected from six sites in urban Mangalore and the mass concentrations for PM10 and PM2.5 were measured using gravimetric technique. The measurements were found to exceed the national ambient air quality standards (NAAQS) limits, with the highest concentration of 231.5 ?g/m3 for PM10 particles at Town hall and 120.3 ?g/m3 for PM2.5 particles at KMC Attavar. The elemental analysis using inductively coupled plasma optical emission spectrophotometer (ICPOES) revealed twelve different elements (As, Ba, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sr and Zn) for PM10 particles and nine different elements (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) for PM2.5 particles. Similarly, ionic composition of these samples measured by ion chromatography (IC) divulged nine different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, K+, Mg2+ and Ca2+) for PM10 particles and ten different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, NH4 +, K+, Mg2+ and Ca2+) for PM2.5 particles. The source apportionment study of PM10 and PM2.5 for urban Mangalore in accordance with these six sample sites using chemical mass balance model (CMBv8.2) revealed nine and twelve predominant contributors for both PM10 and PM2.5, respectively. The highest contributor of PM10 was found to be paved road dust followed by diesel and gasoline vehicle emissions. Correspondingly, PM2.5 was found to be contributed mainly from two-wheeler vehicle emissions followed by four-wheeler and heavy vehicle emissions (diesel vehicles). The current study depicts that the PM10 and PM2.5 in ambient air of Mangalore region has 70% of its contribution from vehicular emissions (both exhaust and non-exhaust). © 2018 Elsevier Ltd
Experimental study of methyl tert-butyl ether as an oxygenated additive in diesel and Calophyllum inophyllum methyl ester blended fuel in CI engine
(Springer Verlag service@springer.de, 2018) Bragadeshwaran, A.; Kasianantham, N.; Ballusamy, S.; Tarun, K.R.; Arumuga Perumal, D.A.; Kaisan, M.U.
This work presents the effect of the ternary oxygenated additive on diesel biodiesel blended fuel to evaluate the engine characteristics. The Calophyllum inophyllum trees being abundant in India can lessen the dependence on petroleum imports to a specific extent. Methyl tertiary butyl ether is used as an oxygenated additive for the ternary blends preparation as 5–20% by volume. Seven blends of neat baseline diesel, biodiesel (Calophyllum inophyllum Methyl Ester), a blend of diesel (50%)-biodiesel (50%), a blend of diesel (50%)-biodiesel-methyl tert-butyl ether (5, 10, 15, and 20%) are prepared which are tested on a single cylinder, constant speed diesel engine. The experimental results were revealed that the replacement of biodiesel by MTBE has shown a slight reduction in brake thermal efficiency with a slight increase in brake-specific fuel consumption. Further, the MTBE addition in ternary blends reduced the unburned hydrocarbon, CO, and NOx by 63.9, 6.4, and 3.37% respectively. In addition, the carbon dioxide emission is almost similar to diesel fuel at a higher addition of MTBE with diesel-biodiesel blend. In the combustion point of view, the addition of 5% MTBE resulted in 3.49 and 5.1% reduction of peak pressure and heat release rate are observed as compared to diesel fuel. Critical analysis in combustion aspects is also carried out and it is witnessed with prolonged ignition delay during MTBE addition with diesel-biodiesel blends. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
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

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