It is believed that adding hydrogen to fuel makes an engine run cleaner as hydrogen is believed to promote complete combustion. This appears to be described, for example, by: Heywood, J. B. in Internal Combustion Engine Fundamentals (McGraw Hill, 773-774, 1988), Das, L. M. in paper xe2x80x9cHydrogen engines: a view of the past and a look into the futurexe2x80x9d (Int. J. Hydrogen Energy, vol. 15, p. 425, 1990), and DeLuchi, M. A. in paper xe2x80x9cHydrogen; and evaluation of fuel storage, performance, safety environmental impacts, and costxe2x80x9d (Int. J. Hydrogen Energy, vol. 14, p. 81, 1989). A problem with these examples was that they failed to explicitly teach how to efficiently generate hydrogen on-board, in compact devices. Alternative approaches of storing hydrogen on-board are not practical because they may require high pressure vessels, cryogenic containers if the hydrogen is to be stored as a compressed gas, liquid, or a large container if the hydrogen is to be stored as a hydride.
Several approaches are believed to have been pursued for on-board production of hydrogen. One of these approaches appear to use electrolysis of water, i.e. breaking down water molecule into hydrogen and oxygen and introducing the hydrogen into an internal combustion engine as stated by Munday, J. F. in xe2x80x9cHydrogen and Oxygen System for Producing Fuel Enginesxe2x80x9d, U.S. Pat. No. 5,143,025. However, it is believed that production of hydrogen by electrolysis is about one order of magnitude less efficient than by plasma devices. Hydrogen can also be produced on-board by water interaction with solid carbon by passing electrical current between the carbon electrodes as stated in Dammann, W. A., xe2x80x9cMethods and Means of Generating Gas from Water for use as a Fuel,xe2x80x9d U.S. Pat. No. 5,159,900, wherein carbon is oxidized to form CO and H2. This approach may be impractical due to the short duration and high current requirement. Alternatively, Greiner, L., and Moard, D. M., xe2x80x9cEmissions Reduction System for Internal Combustion Engines,xe2x80x9d of U.S. Pat. No. 5,207,185, proposed to use a burner, which utilizes a portion of the hydrocarbon fuel to reform another portion to produce hydrogen. The hydrogen is then mixed with the hydrocarbon fuel for introduction into an internal combustion engine. More practical approach seems to be taken by Breshears et al. (see paper by Breshears, R., Cotrill, H., and Rupe, T., xe2x80x9cPartial Hydrogen Injection into Internal Combustion Engines,xe2x80x9d Proc. EPS 1st Symp. On Low Pollution Power Systems Development, Ann Arbor, Mich. 1973). They proposed to direct a fraction of gasoline from the flow path to the engine and pass it through a thermal converter where steam reforms to yield hydrogen-rich gas.
An approach for on-board production of hydrogen for internal combustion engine fuel enrichment has been developed. This approach utilizes a relatively small size plasmatron (believed to be the size of a wine bottle) to facilitate conversion of a wide range of hydrocarbon fuels into hydrogen-rich gas without the use of a catalyst as stated in the following papers: Rabinovich, A., Cohn, D. R., and Bromberg, L., xe2x80x9cPlasmatron Internal Combustion Engine System for Vehicle Pollution Reduction,xe2x80x9d Int. J. Vehicle Design, vol. 15, p. 234, 1995; Cohn, D. R., Rabinovich, A., and Titus, C. H., xe2x80x9cOnboard Plasmatron Operation Generation of Hydrogen for Extremely Low Emission Vehicles with Internal Combustion Engines,xe2x80x9d Int. J. Vehicle Design, vol. 17, p. 550, 1996; Cohn, D. R., Rabinovich, A., Titus, C. H., and Bromberg, L., xe2x80x9cNear Term Possibilities for Extremely Low Emission Vehicles using On-board Plasmatron Generation of Hydrogen,xe2x80x9d Int. J. Hydrogen Energy, vol. 22, p. 715, 1997; Cohn, D. R., Rabinovich, A., Titus, C., xe2x80x9cRapid Response Plasma Fuel Converter Systems,xe2x80x9d U.S. Pat. No. 5,887,554, 1999. An internal combustion engine is connected to receive the hydrogen-rich gas from the plasmatron. A plasmatron is believed to generate plasma by heating an electrically conducting gas either by an arc discharge, by a high frequency inductive or by a microwave discharge. In a plasmatron plasma, at temperatures between 5,000-10,000 K, the reaction rates are high for partial oxidation conversion of a hydrocarbon and air into hydrogen-rich gas. The process which was described by Bromberg, L., Cohn, D., Rabinovich, A., Sama, J., Virolen, J., in the paper xe2x80x9cCompact plasmatron-boosted hydrogen generation technology for vehicular applicationsxe2x80x9d (Inter. Journal of Hydrogen Energy, vol. 24, pp. 341-350, 1999) can be presented as follows:
2CnHm+nO2+4nN2xe2x86x922nCO+mH2+4nN2xe2x80x83xe2x80x83(1) 
where m and n are the numbers of carbon and hydrogen atoms in the hydrocarbon molecule.
The plasmatron is very attractive as one of many ways of producing hydrogen-rich gas for vehicles. It should be possible to almost instantaneously produce hydrogen-rich gas, which can be used in the startup of a vehicle. Throughout the driving cycle, rapid changes in hydrogen-rich gas flow may be accommodated by varying plasmatron parameters such as, for example, energy input, flow rate, product gas composition, etc. Although the plasmatron may be advantageous in vehicle applications, its size is believed to deter a practical application.
The present invention provides a system to deliver fuel through an ignition source. The system of the present invention provides for an ignition source that utilizes a plasma ignition device. The plasma ignition device, which has an arrangement for delivering fuel to the ignition source, also includes a fuel or air and fuel mixture (air/fuel) dissociating device that improves a combustion cycle. The present inventions achieve this improvement by affecting the physical structure of the air/fuel mixture that enters the chamber of a combustion chamber. The present invention provides for a fuel delivery system that dissociates fuel within the combustion chamber. The present invention can dissociate fuel or an air/fuel mixture to improve the quality of the fuel for combustion. The dissociation of the fuel can include hydrogenating the fuel or the air/fuel mixture. The present invention can dissociate fuel and also ignite the fuel. The dissociation and ignition of the fuel, within the system of the present invention, can be accomplished by a single ignition source. The single ignition source could be a high-energy ignition source that has a short duration for generating and moving a plasma. The present invention also provides a fuel delivery system that allows for particularized control of the quality and quantity of the fuel/air mixture supplied to a combustion chamber. The present invention also provides for a direct injection fuel system that can utilize a single component for both dissociating and igniting fuel, air/fuel mixture or a combustible mixture. The present invention also provides a system that reduces the fuel delivery space requirements within an engine compartment.
In one preferred embodiment, the present invention provides for a fuel delivery system. The system comprises an ignitor proximate a combustion region. The ignitor includes a first electrically conductive surface spaced from a second electrically conductive surface to form a gap in direct communication with the combustion region. A fuel supply provides at least one of fuel or air/fuel mixture to the gap. A controller provides at least one electrical pulse between the first conductive surface and second conductive surface that dissociates at least one of fuel or air /fuel mixture passing through the discharge gap.
In another preferred embodiment, the present invention provides for a fuel delivery system. The system comprises an ignitor proximate a combustion region. The ignitor includes a housing, a first electrically conductive surface, a second electrically conductive surface spaced from the first electrically conductive surface to form a discharge gap. The second electrically conductive surface has a second length. The shorter of the first and second lengths defines a discharge gap length. The shortest distance between the first electrically conductive surface and the second electrically conductive surface defines a discharge gap width. A ratio of the discharge gap width to the discharge gap length being greater than one to three. A fuel supply is operatively connected to ignitor to provide at least one of fuel or air/fuel mixture to the discharge gap. A controller provides at least one electrical pulse between the first electrically conductive surface and second electrically conductive surface.
In another preferred embodiment of the invention, a fuel delivery system is provided. The fuel delivery system comprises an ignitor proximate a combustion region. The ignitor includes a first electrically conductive surface spaced from a second electrically conductive surface to form a discharge gap in direct communication with the combustion region. An insulator has a surface exposed to the discharge gap. The discharge gap has an initiation region, the insulator has a surface exposed to the discharge gap that provides at least a portion of the initiation region. The insulator has at least a portion of a surface exposed to the discharge gap. A fuel supply provides at least one of fuel or air/fuel mixture to the discharge gap. A controller is also provided with the system.
In another preferred embodiment, the present invention provides for a fuel delivery system. The system comprises an ignitor coupled to the combustion region. The ignitor includes a housing has first portion and a second portion disposed along a central longitudinal axis, an electrode extends along the central longitudinal axis and has a first electrically conductive surface proximate the second portion of the housing, a second electrically conductive surface proximate the second portion of the housing and spaced from the first electrically conductive surface to form a discharge gap, a fuel supply to provide at least one of fuel or air/fuel mixture to the discharge gap. The system includes a controller that provides at least one electrical pulse between the first electrically conductive surface and second electrically conductive surface.
In another preferred embodiment, an ignitor comprises a housing having a first portion and a second portion, a first electrically conductive surface proximate the second portion of the housing, a second electrically conductive surface proximate the second portion of the housing and spaced from the first electrically conductive surface to form a discharge gap. The discharge gap has a discharge initiation region. A fluid passage extends between the first portion and the second portion of the housing, the fluid passage being in communication with the discharge gap. An insulator has a surface exposed to the discharge gap.
In another embodiment, an ignitor comprises a housing having a first portion and a second portion, a first electrically conductive surface proximate the second portion of the housing, the first conductive surface having a first length, a second electrically conductive surface spaced from the first electrically conductive surface to form a discharge gap. The second electrically conductive surface has a second length. The shorter of the first and second lengths defines a discharge gap length. The shortest distance between the first electrically conductive surface and the second electrically conductive surface define a discharge gap width, where a ratio of the discharge gap width to the discharge gap length being greater than about one to about three. A fluid passage extends between the first portion and the second portion. The fluid passage being in communication with the discharge gap.
In a preferred embodiment, the present invention provides an ignitor. The ignitor comprises a housing having a first portion and a second portion disposed along a central longitudinal axis. An electrode extends along the central longitudinal axis and having a first surface proximate the second portion of the housing, a second electrically conductive surface proximate the second portion of the housing and spaced from the first electrically conductive surface to form a discharge gap. A fluid passage extends between the first portion and the second portion, the fluid passage being spaced from the longitudinal axis and in communication with the discharge gap.
In another preferred embodiment, the present invention provides for a method of dissociating fuel for a combustion system. The combustion system has a combustion region, a fuel supply operatively connected to the combustion region, an ignition device having a first electrically conductive surface and a second electrically conductive surface spaced from the first electrically conductive surface to form a discharge gap. The method comprises locating the ignition device so that the discharge gap is in direct communication with the combustion region; and dissociating the at least one of fuel or air/fuel mixture by the discharge gap.
In a preferred embodiment, the present invention provides for a method of ionizing at least one of fuel or air/fuel mixture for a combustion system. The combustion system has a combustion region, a fluid supply is operatively connected to the combustion region, an ignition device having a first electrically conductive surface and a second electrically conductive surface spaced from the first electrically conductive surface to form a discharge gap. The method comprises locating the ignition device so that the discharge gap is in direct communication with the combustion region; and ionizing the fluid within the discharge gap.
In a preferred embodiment, the present invention provides for a method of igniting at least one of fuel or air/fuel mixture in a combustion region by a device having at least one central electrode disposed along a longitudinal axis, a discharge gap formed between the at least one electrode and another electrode. The discharge gap being disposed about the central electrode. The method comprises dispensing at least one of fuel or air/fuel mixture to the discharge gap; and creating at least one electrical pulse across the discharge gap so that the at least one of fuel or air/fuel mixture is combusted and projected radially outward with respect to the longitudinal axis.
In a preferred embodiment, the present invention provides for a method of igniting at least one of fuel or air/fuel mixture in a combustion system. The combustion system has a combustion region, a fuel supply operatively connected to the combustion region, an ignition device having a first electrically conductive surface and a second electrically conductive surface spaced from the first electrically conductive surface. The method comprises passing an electrical pulse of first voltage at a first current to the first electrically conductive surface and a second electrically conductive surface, the first electrically conductive surface has a first length, the second electrically conductive surface has a second length, the shorter of the first and second lengths defines a discharge gap length, the shortest distance between the first electrically conductive surface and the second electrically conductive surface define a discharge gap width, where a ratio of the discharge gap width to the discharge gap length being greater than one to three; and passing a second electrical pulse less than or equal to the first voltage at a second current greater than or equal to the first.