This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Initial Studies of a New Type of Ignitor: The Railplug
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 01, 1991 by SAE International in United States
Annotation ability available
Initial investigations of a new type of high energy ignitor for I.C. engines are described. The ignitor is a miniaturized railgun, or “railplug.” The railplug produces a relatively large mass of high velocity plasma. These characteristics may be advantageous for initiating combustion in a number of different applications. Unlike a plasma jet ignitor, the railplug plasma is driven not only by thermodynamic expansion, but by electromagnetic forces as well. Four experimental railplug designs were evaluated using schlieren and shadowgraphy visualization to examine plasma movement and shape. Railplug current and voltage were also measured. One railplug consisting of two unenclosed parallel rails was used to demonstrate the electromagnetically induced motion of the plasma at ambient conditions. Schlieren photos showed that the plasma plume moves strongly in the direction of the electromagnetic Lorentz forces. Two transparent railplugs, one with short rails (24 mm) and the other with long rails (35 mm), were tested to show plasma motion and structure inside the plug cavity. Plasma exit velocities in excess of 300 m/s were observed for the transparent railplug with short rails in air at ambient conditions. Schlieren imaging of the transparent railplugs proved that proper matching of the railplug with the electronics is essential. In the long transparent railplug, a collapse of the current while the plasma was still in the plug cavity resulted in generation of eddy currents which rapidly decelerated the plasma preventing it from reaching the plug exit. A fourth railplug was used to ignite lean (ϕ=0.85) quiescent methane-air mixtures at 3.3 atm total pressure in a constant volume bomb. For the bomb experiments, schlieren imaging and pressure histories were obtained and compared with ignition using a conventional spark plug and surface gap ignitor with the same energy as the railplug. Rates of pressure rise in the combustion bomb were much greater for the railplug compared with the conventional spark plug or the surface gap ignitor; the time to peak pressure was approximately cut in half by the railplug.
|Technical Paper||Further Analysis of Railplugs as a New Type of Ignitor|
|Technical Paper||Examination of the Factors that Influence the Durability of Railplugs|
|Technical Paper||Impact of Railplug Circuit Parameters on Energy Deposition and Durability|
- M.J. Hall - Department of Mechanical Engrg., The University of Texas at Austin
- H. Tajima - Department of Mechanical Engrg., The University of Texas at Austin
- Ronald D. Matthews - Department of Mechanical Engrg., The University of Texas at Austin
- M.M. Koeroghlian - Department of Mechanical Engrg., The University of Texas at Austin
- W.F. Weldon - Center for Electro-Mechanics Department of Mechanical Engrg., The University of Texas at Austin
- S.P. Nichols - Center for Electro-Mechanics Department of Mechanical Engrg., The University of Texas at Austin
CitationHall, M., Tajima, H., Matthews, R., Koeroghlian, M. et al., "Initial Studies of a New Type of Ignitor: The Railplug," SAE Technical Paper 912319, 1991, https://doi.org/10.4271/912319.
- Dale, J.D., and Oppenheim A.K., “Enhanced ignition for I.C. engines with premixed gases”, SAE Paper 810146, 1981.
- Wall Street Journal, July 30, 1991.
- Namekawa, S., Ryu H., and Asanuma T., “LDA measurement of turbulent flow in a motored and firing spark-ignition engine with a horizontal prechamber”, SAE Paper 881636, 1988.
- Wyczalek, F.A., “Plasma jet ignition of lean mixtures”, SAE Paper, 750349, 1975.
- Asik, J.R., Piatkowski P., Foucher M.J., and Rado W.G., “Design of a plasma jet ignition system for automotive application”, SAE Paper 770355, 1977.
- Edwards, C.F., Oppenheim A.K., and Dale J.D., “A comparative study of plasma ignition systems”, SAE Paper 830479, 1983.
- Kupe, J., Wilhelm H., and Adams W., “Operational characteristics of a lean burn S.I. engine: comparison between plasma-jet and conventional ignition systems”, SAE Paper 870608, 1987.
- Smy, P.R., Clements R.M., and Topham D.R., “Efficiency and erosion of plasma jet ignitors”, Comb. Sci. and Tech., 42: 317-324 (1985).
- Orrin, J.E., Vince I.M., and Weinberg F.J., “A study of plasma jet ignition mechanisms”, Eighteenth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, 1981.
- Dale, J.D., Smy P.R., and Clements R.M., “The effects of a coaxial spark igniter on the performance of and the emissions from an internal combustion engine”, Combustion and Flame 31:173-185 (1978).
- Edwards, C.F., Stewart H.E., and Oppenheim A.K., “A photographic study of plasma ignition system,,” SAE Paper 850077, 1985.
- Modien, R.M., and Dale J.D., “The effect of enhanced ignition systems on early flame development in quiescent and turbulent conditions”, SAE Paper 910564, 1991.
- Murase, E., Ono S., Hanada K., and Nakahara S., “Plasma jet ignition in turbulent lean mixtures”, SAE Paper 890155, 1989.
- Tozzi, L., and Dabora E.K., “Plasma jet ignition in a lean-burn CFR engine”, Nineteenth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, pp. 1467-1474, 1982.
- Fitzgerald, D.J., “Pulsed plasma ignitor for internal combustion engines”, SAE Paper 760764, 1976.
- Fitzgerald, D.J., U.S. Patent 4,122,816, 1978.
- Clements, R.M., Smy P.R., and Dale J.D., “An experimental study of the ejection mechanism for typical plasma jet ignitors”, Combustion and Flame 42:287-295 (1981).
- Oppenheim, A.K., Teichman K., Hom K., and Stewart H.E., “Jet ignition of an ultra-lean mixture”, SAE Paper 780637, 1978.
- Weinberg, F.J., Hom K., Oppenhiem A.K., and Teichman K., “Ignition by plasma jet”, Nature 272:341-343 (1978).
- Oppenheim, A.K., Beltramo J., Faris D.W., Maxson J.A., Hom K., and Stewart H.E., “Combustion by pulsed jet plumes - key to controlled combustion engines”, SAE Paper 890153, 1989.
- Bradley, D., and Crichley I.L., “Electromagnetically induced motion of spark ignition kernels”, Combustion and Flame 22:143-15 (1974).
- Harrison, A.J., and Weinberg F.J., “A note on electromagnetically induced motion of spark ignition kernels”, Combustion and Flame 22:263-265 (1974).