Effect of Turbulent Flame Propagation Velocity and Zone Width on the Unburnt Hydrocarbon Concentration and Combustion Efficiency in a Spark-Ignition Engine

Authors: Shaykin A.P., Galiev I.R. Published: 05.09.2019
Published in issue: #4(127)/2019  

DOI: 10.18698/0236-3941-2019-4-111-123

Category: Power, Metallurgic and Chemical Engineering | Chapter: Heat Engines  
Keywords: combustion efficiency, unburnt hydrocarbons, width, velocity, flame

The investigation considers how combustion efficiency and exhaust gas (unburnt hydrocarbon) toxicity are linked to the fundamental flame propagation characteristics (flame propagation velocity and reaction zone width). We present combustion efficiency and unburnt hydrocarbon concentration as functions of fundamental flame propagation characteristics, maximum flame temperature, flame failure temperature and thickness of the unburnt fuel layer adjacent to the combustion chamber walls. Comparing combustion efficiency computed according to the equation proposed to combustion efficiency derived by using an experimentally obtained indicator diagram showed that the data are in good agreement. We studied the connection between unburnt hydrocarbon emission and combustion efficiency. We detected that increasing combustion efficiency leads to lower unburnt hydrocarbon emission, which is explained by reduction of the unburnt fuel ratio in the layer adjacent to the wall. We propose a new technique for calculating unburnt hydrocarbon amount in engine exhaust gases. We show that our technique makes it possible to determine the chemical composition of the air-fuel mixture and the values of flame propagation characteristics that ensure a decrease in unburnt hydrocarbon emission. The results of our study may be used to develop or refine methods of increasing combustion efficiency of composite fuels and reducing exhaust gas toxicity in combustion chambers of internal combustion engines and other power plants

The study was conducted as part of a government order, project no. 394, supported by the Government of Samara Region as part of the monetary benefit program for young scientists and designers of Samara Region, as well as by the Ministry of Education and Science of the Russian Federation as part of the program providing young scientists with scholarships of the President of the Russian Federation


[1] Nanthagopal K., Subbarao R., Elango T., et al. Hydrogen enriched compressed natural gas (HCNG]: а futuristic fuel for internal combustion engines. Therm. Sci., 2011, vol. 11, no. 4, pp. 1145--1154. DOI: 10.2298/TSCI100730044N

[2] Rakopoulos C.D., Scott M.A., Kyritsis D.C., et al. Availability analysis of hydrogen/natural gas blends combustion in internal combustion engines. Energy, 2008, vol. 33, no. 2, pp. 248--255. DOI: 10.1016/j.energy.2007.05.009

[3] Shaikin A.P., Galiev I.R. Relationship of flame propagation speed for methane–hydrogen fuel of the internal combustion engine with parameters of ion current and hydrogen concentration. Russ. Aeronaut., 2016, vol. 59, no. 2, pp. 249--253. DOI: 10.3103/S106879981602015X

[4] Zeldovich Ya.B., Barenblatt G.I., Librovich V.B., et al. The mathematical theory of combustion and explosions. Consultants Bureau, 1985.

[5] Heywood J.B. Internal combustion engine fundamentals. McGraw–Hill, 1988.

[6] Hermanns R.T. Laminar burning velocities of methane–hydrogen–air mixtures. Doctoral thesis. Technische Universiteit Eindhoven, 2007.

[7] Verhelst S., Woolley R., Lawes M., et al. Laminar and unstable burning velocities and Markstein lengths of hydrogen–air mixtures at engine-like conditions. Proc. Combust. Inst., 2005, vol. 30, no. 1, pp. 209--216. DOI: 10.1016/j.proci.2004.07.042

[8] Gel’fand B.E., Popov O.E., Chayvanov B.B. Vodorod: parametry goreniya i vzryva [Hydrogen: the parameters of combustion and explosion]. Moscow, Fizmatlit Publ., 2008.

[9] Shaikin A.P., Galiev I.R. On the effect of temperature and the width of the turbulent combustion zone on the ionization detector readings. Tech. Phys., 2016, vol. 61, no. 8, pp. 1206--1208. DOI: 10.1134/S1063784216080247

[10] Shaykin A.P., Ivashin P.V., Galiev I.R., et al. Kharakteristiki rasprostraneniya plameni i ikh vliyanie na obrazovanie nesgorevshikh uglevodorodov i oksida azota v otrabotavshikh gazakh pri dobavke vodoroda v toplivno-vozdushnuyu smes’ energeticheskikh ustanovok s iskrovym zazhiganiem [Characteristics of flame propagation and its influence on formation of unburned hydrocarbons and nitric oxide in the exhaust gases with addition of hydrogen to fuel-air mixture of power plants with spark ignition]. Samara, Samarskiy nauchnyy tsentr RAS Publ., 2016.

[11] Chang W. An improved method of investigation of combustion parameters in a natural gas fuelled SI engine with EGR and H2 as additives. Doctoral thesis. University of Birmingham, 2002.

[12] Park J., Cha H., Song S. A numerical study of a methane–fueled gas engine generator with addition of hydrogen using cycle simulation and DOE method. Int. J. Hydrogen Energy, 2011, vol. 36, no. 8, pp. 5153--5162. DOI: 10.1016/j.ijhydene.2011.01.019

[13] Sierens R. Variable composition hydrogen/natural gas mixtures for increased engine efficiency and decreased emissions. J. Eng. Gas Turbines Power, 2000, vol. 122, no. 1, pp. 135--140. DOI: 10.1115/1.483191

[14] Ma F., Naeve N., Wang M., et al. Hydrogen-enriched compressed natural gas as a fuel for engines. Natural Gas. IntechOpen, 2010, pp. 307--332.