This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
A Study of H2, CH4, C2H6 Mixing and Combustion in a Direct-Injection Stratified-Charge Engine
Annotation ability available
Sector:
Language:
English
Abstract
The combustion characteristics of three gaseous fuels (hydrogen, methane and ethane) in a direct-injection stratified-charge single-cylinder engine with a centered square head-cup operated at 800 rpm (compression ratio = 10.8, squish ratio = 75%, nominal swirl ratio = 4) were studied to assess the extent to which the combustion is controlled by turbulent mixing, laminar mixing and chemical kinetics. The injection of gaseous fuels was via a Ford AFI injector, originally designed for the air-forced injection of liquid fuel. Pressure measurements in the engine cylinder and in the injector body, coupled with optical measurements of the injector poppet lift and shadowgraph images of the fuel jets provided both quantitative and qualitative information about the in-cylinder processes.
To make the cases comparable, the total momentum of the fuel jets and the total heat released by the three fuels was kept the same (equivalence ratio = 0.316, 0.363, 0.329 for H2, CH4 and C2H6, respectively). The total momentum of the gas jets was calculated using the measured values of the flow coefficient, under the assumption of a quasi-steady flow through the injector, coupled with the measured values of the cylinder and injector body pressures. With a spark timing of 14° BTDC, combustion was fast and repeatable for all fuels (COV = 1.2%, 4% and 2.2% for H2, CH4 and C2H6, respectively).
All indications suggest that the combination of direct injection, high squish, high swirl and square cup in the engine head produced fast mixing and a high degree of mixture uniformity within the head cup at combustion time; thus turbulence intensity, molecular diffusion and chemical kinetics were the main contributors to the establishment and propagation of the turbulent flame. The effect of chemical kinetics was particularly significant in the early stages of combustion and the laminar flame speed remained relevant during the major part of the combustion event.
Recommended Content
Authors
Citation
De Risi, A., Gajdeczko, B., and Bracco, F., "A Study of H2, CH4, C2H6 Mixing and Combustion in a Direct-Injection Stratified-Charge Engine," SAE Technical Paper 971710, 1997, https://doi.org/10.4271/971710.Also In
References
- Ricardo, H.R. “Recent Work on the Internal Combustion Engine,” SAE Journal 10 1922
- Obert, E.F. “Internal Combustion Engines and Air Pollution,” Harper and Row, Publishers Inc. 1973
- Ghandhi, J.B. Bracco, F.V. “Fuel Distribution Effects on the Combustion of a Direct-Injection Stratified-Charge Engine,” SAE Paper 950460 1995
- Ghandhi, J.B. Felton, P.G. Gajdeczko, B.F. Bracco, F.V. “Investigation of the Fuel Distribution in a Two-Stroke Engine with an Air-Assisted Injector,” SAE paper 940394 1994
- Witsky, J.C. “Stratified Charge Engines” ASME paper 63-MD-42 1963
- Evers, L.W. Fleming, R.D. Hurn, R.W. “Efficiency and Emissions of a Stratified Charge Engine Optimized for Various Fuels” SAE paper 780236 1978
- Balles, E.N. Ekchian, J.A. Heywood, J.B. “Fuel Injection Characteristics and Combustion Behavior of a Direct-Injection Stratified-Charge Engine” SAE paper 841379 1984
- Abraham, J. Bracco, F.V. “Combustion Optimization Computations-Part I: Swirl and Squish Effects in Air-Assist Injection Engines” SAE paper 922240 1992
- Schechter, M. M. Levin, M. B. “Air-Forced Fuel Injection System for 2-Stroke D.I. Gasoline Engine,” SAE paper 910664 1991
- Lancaster, D. R. Krieger, R.B. Linesch, J. H. “Measurements and Analysis of Engine Pressure Data” SAE paper 750026 1975
- Witze, P.O. Vilchis, F.R. “Stroboscopic Laser Shadowgraph Study of the Effect of Swirl on Homogenous Combustion in a Spark Ignition Engine,” SAE paper 810226 1981
- MacInnes, J.M. Bracco, F.V. “Computation of the Spray from an Air-Assisted Fuel Injector” SAE paper 902079 1990
- Cho, Y.O. Santavicca, D.A. Sonntag, R.M. “The effect of Spark Power on Spark-Ignited Flame Kernel Growth” SAE paper 922168 1992
- Iijima, T. Bracco, F.V. “LDV Measurements in an Engine with Square and Circular Piston Cups” SAE paper 872073 1987
- Fraser, R.A. Bracco, F.V. “Cycle Resolved LDV Integral Length Scaling, Isotropy and Homogeneity in an I.C. Engine” SAE paper 890615 1989
- Magi, V. Bracco, F.V. “Comparisons of Computed and Measured Flow Field and Combustion in a Cup-in-Head Stratified-Charge Engine”
- Anderson, R.W. Asik, J.R. “Ignitability Experiments in a Fast Burn, Lean Burn Engine” SAE paper 850076 1985
- Pischinger, S. Heywood, J.B. “A Study of Flame Development and Engine Performance with Breakdown Ignition System in a Visualization Engine” SAE paper 880518 1988
- Anderson, R.W “The Effect of Ignition System Power on Fast Burn Engine Combustion” SAE paper 870549 1987
- Calcote, H.F. Gregory, C.A., Jr. Barnet, C.M. Gilmer, R.B. Ind. Eng. Chem. 44 2656 1952
- Egolfopoulos, F.N. Law, C.K. “An Experimental and Computational Study of the Burning Rates of Ultra-Lean to Moderately-Reach H2/O2/N2 Laminar Flames with Pressure Variations” twenty-third Symposium (International) on Combustion 1990 333 340
- Andrews, G.E. Bradley, D. “The Burning Velocity of Methane-Air Mixtures” Combustion and Flame 19 1972 275 288
- Gibbs, G.J. Calcote, H.F. J. Chem. Eng. Data 5 1959
- Milton, B.E. Keck, J.C. “Laminar burning velocities in Stoichiometric Hydrogen and Hydrogen-Hydrocarbon Gas Mixtures” Combustion and Flame 58 1984 13 22
- Halstead, M.P. Pye, D.B. Quinn, C.P. “Laminar Burning Velocities and Weak Flammability Limits Under Engine-Like Conditions” Combustion and Flame 22 1974 89 97
- Peters, N. “Laminar Flamelet Concepts in Turbulent Combustion” twenty-first Symposium (International) on Combustion The Combustion Institute 1986 1231 1250
- Klimov, A.M. “Premixed Turbulent Flames-Interplay of Hydrodynamic and Chemical Phenomena” Flames, Lasers and Reactive Systems, Vol. 88 of Progress in Astronautics and Aeronautics Bowen J.R. Manson N. Oppnheim A.K. Soloukhin R.I. American Institute of Aeronautics and Astronautics New York The Combustion Institute 1985 403 410
- Witze, P.O. Mendes-Lopez, J. M. C. “Direct Measurements of the Turbulent Burning Velocity in a Homogeneous-Charge Engine” SAE paper 861531 1986
- Mantzaras, J. Felton, P.G. Bracco, F.V. “Is a Laminar Flame Front a Passive Scalar Surface of the Turbulent Field?” Third Joint ASCE/ASME Mechanics Conference San Diego, California July 9-12 1989
- Mantzaras, J. Felton, P.G. Bracco, F.V. “Fractal and Turbulent Premixed Engine Flames” Combustion and Flame 77 1989 295 310