Patent Abstract:
An apparatus and method for the creation, placement and control of an area of electrical ionization within an internal combustion engine combustion chamber or a fuel burner for a furnace is disclosed. A furnace includes a fuel source, a fuel burner, a plasma nozzle and igniter assembly, and the associated housing and flue structures. The plasma nozzle and igniter assembly is arranged so that the fuel sprayed out from the nozzle into the combustion area passes through or in close proximity to the area of plasma ionization. A fuel burner equipped with this electrical ionization device has its fuel efficiency enhanced by the complete and immediate combustion of substantially all of the fuel that passes through the area of plasma ionization. Exhaust gas recirculation using this system is also disclosed.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This new application is a continuationin-part application of U.S. patent application Ser. No. 10/321,721 filed on Dec. 18, 2002, now U.S. Pat. No. 6,883,490, which is a continuation of U.S. application Ser. No. 09/954,195 filed on Sep. 18, 2001, now abandoned, which is a continuation of U.S. application Ser. No. 09/501,788 filed on Feb. 11, 2000, now U.S. Pat. No. 6,289,868. These prior applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for improving fuel burners in furnaces by using a plasma ignition system. 
     2. Description of the Related Art 
     As described in applicant&#39;s prior applications listed above and incorporated herein by reference, there are numerous problems with the combustion process for diesel engines. None of the prior art references disclosed an apparatus that will allow for the initiation of combustion for all of the fuel as it is injected into the combustion chamber followed by the maintenance of the combustion process to its completion in the manner described therein. 
     Also, fuel burner technology for furnaces usually relies upon a simple electrical arc discharge ignition system, usually positioned to one side of the fuel spray coming out of the nozzle. In some cases the ignition system is as primitive as a simple pilot light for flame ignition. 
     Although these oil burner ignition systems are simple, reliable, and cheap they have absolutely no fuel treatment capability. This lack of point of use fuel treatment results in four serious limitations: 
     1. Less than optimal fuel efficiency as a result of incomplete combustion; 
     2. Pollutant emissions as evidenced by the production of oxides of nitrogen (NO x ), carbon monoxide (CO), hydrocarbons, and particulates (soot) that are observed in the exhaust output; 
     3. Unstable combustion when dealing with fuel that has been contaminated by water; and 
     4. Imposed limitations on the fuel oil weight used in a given burner design. 
     To date, a variety of methods have been employed to improve the efficiency of and reduce pollution from fuel oil burners used in furnaces and similar systems. Higher fuel pressures, smaller fuel nozzle orifice sizes, different fuel nozzle configurations, improved fuel/air mixing arrangements, fuel pre-heating, and improved heat exchanger systems have provided for improved fuel efficiency and some reduction in pollutant emissions. 
     None of these approaches has the effect of chemically altering the fuel on its molecular level. 
     As best understood, the present invention chemically alters the fuel in the combustion process directly at the fuel&#39;s point of use, changing the fuel&#39;s chemical structure right after it leaves the fuel oil burner&#39;s nozzle as it enters the combustion area. This enhances the fuel combustion process significantly. These benefits of the present invention are complimentary with and in addition to those realized by the previously mentioned methods currently in use. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the present invention to provide an apparatus and method for assuring the immediate and complete combustion of any hydrocarbon fuel sprayed into the combustion area of furnaces and similar systems. 
     It is a further object of the present invention to make it possible to easily retrofit this apparatus to existing furnaces and also to provide a method for assuring the complete combustion of any hydrocarbon fuels in the existing fuel burners. 
     An area of ionizing electrical energy, effectively an electrical catalyst, (for purposes of illustration, it is referred to as a “plasma ball” or “ring-of-fire”) is created inside the combustion area directly in front of the fuel nozzle. The placement of this plasma ball is critical in that all of the fuel must pass through the plasma ball as it enters the combustion area. 
     Plasma created between the electrodes of the plasma ball generator of the present invention may not be perfectly spherical in shape. The term “plasma ball” or “ball of plasma” as used herein, includes a spherical shaped plasma as well as other polygonal shapes, such as a partially flattened sphere or an elongated hemisphere. When the plasma discharge is operated in still air with the electrodes placed closely together the shape of the discharge, while being close to spherical to the naked eye, is more accurately an ellipsoid. When the plasma discharge is being put to work, the movement of air and fuel through the plasma ball distorts it further from the ellipsoid shape to a shape similar to a tee-pee with the pole ridges marking the electrode locations. As long as the plasma discharge is vigorous, the change in shape does not have a significant effect on the performance of the plasma. 
     Plasma is defined in the world of physics as a state of matter where the electrons that normally orbit the nucleus of an atom are instead dissociated from the nucleus. For the purposes of the present invention, it is unnecessary and inefficient to create pure plasma in which all of the electrons of all of the atoms are separated from all of the nuclei. The partial plasma created by the present invention strips off enough electrons to do what needs to be done for effective fuel treatment to take place. 
     These outer electrons are referred to as outer valence electrons. As best understood, these are the electrons that the “Plasma ball” created by the present invention is adept at removing. By having the correct shared outer electrons stripped away from the carbon atoms of the fuel molecules, these fuel molecules are broken down into shorter chain hydrocarbon fuel molecules such as, but not limited to methane, ethane, propane, butane, and pentane that are well known to burn much cleaner than almost all longer chain hydrocarbons. 
     This treatment of the fuel using the plasma ball ignition system also does other functions. It is believed that in addition to breaking down the fuel molecule into shorter chain hydrocarbons, it also puts an electrical charge onto each shorter chain hydrocarbon molecule. The effect of this electrical charge on the shorter chain hydrocarbon molecules is to increase its reactivity to oxygen dramatically. All that is needed for the shorter chain hydrocarbon molecules to ignite is for them to come into contact with oxygen. 
     The same molecular dissociation that breaks fuel oil molecules down also enables oil burners equipped with the present invention to deal with water contamination of the fuel with ease. When water mixed with the fuel passes through the “Plasma ball” it is believed to be electrolyzed into hydrogen and oxygen and then the hydrogen ignites and burns with the rest of the fuel without interfering with the overall combustion stability. 
     Both the chemistry of the fuel and the combustion process itself are completely changed by the “Plasma ball” point of use fuel treatment method and apparatus when utilized in a hydrocarbon fuel burner. It is believed to act as an electrical catalyst which greatly promotes the immediate and complete combustion of all of the fuel resulting in the following advantageous effects: 
     1) Greater fuel efficiency as a result of earlier completion of combustion thus allowing more time for heat transfer from the combustion gases to the heat exchanger wall. 
     2) Greater fuel efficiency than available from the present technology oil burners by burning completely those hydrocarbon components usually coming out of the exhaust flue as hydrocarbon emissions such as carbon monoxide, particulate matter, soot, and others. 
     3) Reduced hydrocarbon pollutant emissions as a direct result of complete combustion of all of the fuel. 
     4) The ability to greatly reduce pollutant emissions of oxides of nitrogen by making possible the much more aggressive utilization of exhaust gas recirculation without the loss of combustion efficiency. 
     5) The ability to maintain stable combustion when using fuels contaminated with water. 
     6) The ability to effectively and efficiently use heavier weight fuel oils that cost much less due to the present invention&#39;s ability to convert these lower quality fuels into much easier to combust compounds at the point of use. 
     The efficacy of the “Plasma ball” point of use fuel treatment and ignition system is evidenced by the empirical observations made during a series of side-by-side comparative tests. For this testing program, a Riello model 40F10 oil burner was retrofitted with the plasma ball point of use fuel treatment system and installed in a furnace heating a commercial building and compared to exactly the same furnace and oil burner setup next to each other under the same conditions at the same time. Fuel efficiency was improved on average 7.6% with over-all pollutant emissions reduced between 25 to 35%, depending on the specific pollutant. Earlier testing done on a home heating furnace with a retrofitted Beckett oil burner according to the present invention had the result of showing no detectable particulates and a carbon monoxide level below that which could be detected by the testing equipment being used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and features of the present invention will be clearly understood from the following description with respect to the preferred embodiment thereof when considered in conjunction with the accompanying drawings and diagrams, in which: 
         FIG. 1  is a cross sectional side view of the injector/igniter apparatus of the present invention installed in an engine cylinder head. 
         FIG. 2  is a cross sectional side view of the injector/igniter apparatus of the present invention installed in an engine cylinder head with fuel being injected into the combustion chamber. 
         FIG. 3A  is an enlarged side view of the lower end of the injector/igniter apparatus that extends through the cylinder head. 
         FIG. 3B  is an enlarged bottom view of the injector/igniter apparatus. 
         FIG. 3C  is an enlarged side view of the injector/igniter apparatus rotated by 90 degrees from the view presented in  FIG. 3A . 
         FIG. 3D  is an enlarged perspective view of the injector/igniter apparatus. 
         FIG. 4A  is an enlarged side view of the injector/igniter apparatus with the Ring-of-Fire shown in operation. 
         FIG. 4B  is an enlarged bottom view of the injector/igniter apparatus with the Ring-of-Fire shown in operation. 
         FIG. 4C  is an enlarged side view of the injector/igniter apparatus rotated by 90 degrees from the view presented in  FIG. 4A . 
         FIG. 4D  is an enlarged perspective view of the injector/igniter apparatus with the Ring-of-Fire shown in operation. 
         FIG. 5A  is an enlarged side view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a pintle type of fuel injector. 
         FIG. 5B  is an enlarged bottom view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a pintle type of fuel injector. 
         FIG. 5C  is an enlarged side view of the injector/igniter apparatus rotated by 90 degrees from the view presented in  FIG. 5A  with the Ring-of-Fire shown in operation and with fuel being injected by a pintle type of fuel injector. 
         FIG. 5D  is an enlarged perspective view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a pintle type of fuel injector. 
         FIG. 6A  is an enlarged side view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a hole type of fuel injector. 
         FIG. 6B  is an enlarged bottom view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a hole type of fuel injector. 
         FIG. 6C  is an enlarged side view of the injector/igniter apparatus rotated by 90 degrees from the view presented in  FIG. 6A  with the Ring-of-Fire shown in operation and with fuel being injected by a hole type of fuel injector. 
         FIG. 6D  is an enlarged perspective view of the injector/igniter apparatus with the Ring-of-Fire shown in operation and with fuel being injected by a hole type of fuel injector. 
         FIG. 7A  is a cross sectional side view of the injector/igniter apparatus of the present invention. 
         FIG. 7B  is a top view of the injector/igniter apparatus of the present invention. 
         FIG. 7C  is a bottom view of the injector/igniter apparatus of the present invention. 
         FIG. 8A  is a cross sectional side view of the ceramic sleeve portion of the injector/igniter apparatus of the present invention. 
         FIG. 8B  is a top view of the ceramic sleeve portion of the injector/igniter apparatus of the present invention. 
         FIG. 8C  is a bottom view drawing of the ceramic sleeve portion of the injector/igniter apparatus of the present invention. 
         FIG. 9  is a block diagram of the signal generation circuit portion of the present invention. 
         FIG. 10A  is a timing signal diagram of the square-wave signal created by the square-wave generator in the signal generation circuit of the present invention. 
         FIG. 10B  is a timing signal diagram of the six sequential signals created by the signal divider circuit in the signal generation circuit of the present invention. 
         FIG. 10C  is a timing signal diagram of the six overlapped sequential signals created by the signal overlap circuit in the signal generation circuit of the present invention. 
         FIG. 11  is a schematic of one of the high voltage discharge circuits of the present invention. 
         FIG. 12  is a diagram depicting all six high voltage discharge circuits attached to the ceramic sleeve portion of the injector/igniter apparatus of the present invention. 
         FIG. 13  is a side view of an entire furnace system with an oil burner equipped with the plasma point of use fuel treatment and exhaust gas recirculation system according to another embodiment of the present invention. 
         FIG. 14  is an enlarged side view of an oil burner fuel spray nozzle and igniter assembly removed from the burner air tube for clarity. 
         FIG. 15  is a side view of an oil burner equipped with the nozzle and igniter assembly of the present invention with the air tube partially cut away for clarity. 
         FIG. 16  is an enlarged front end view of the plasma electrode tips arrayed around the fuel spray nozzle with the flame retention plate in place according to the present invention. 
         FIG. 17  is a front end view of the plasma electrode tips arrayed around the fuel spray nozzle with the flame retention plate and electrode tip insulators removed for clarity. 
         FIG. 18  is a schematic of one of the improved high voltage discharge circuits that supply a multi-frequency high voltage output to one electrode of the nozzle and igniter assembly of the present invention. 
         FIG. 19  is a diagram depicting a signal generation circuit and six high voltage discharge circuits that produce the multi-frequency high voltage outputs that supply the electrodes of the nozzle and igniter assembly in a fuel burner according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention will now be described in further detail in connection with illustrative preferred embodiments for improving combustion in a direct injected internal combustion engine enabling the engine to achieve better fuel economy, reduced pollutant emissions, and more power. Within the scope of the present invention, this system could be applied to gas turbines and to reciprocating internal combustion engines that are direct injected of either the 2-stroke or the 4-stroke type that have been designed for use with any type of combustible fuel including gasoline, diesel or jet fuel. 
     Referring to  FIG. 1 , the present invention is shown mounted in a cylinder head  15  of a diesel engine. An engine block  11  has placed inside it a piston  13  and mounted on top of the engine block  11  is the cylinder head  15 . A combustion chamber  17  is located inside the area surrounded by the engine block  11 , the piston  13 , and the cylinder head  15 . Passing through the cylinder head  15  is a fuel injector  21  that has its lower body surrounded by a ceramic sleeve  23 . A fuel inlet  25  attached to the upper portion of the fuel injector  21  has a fuel passageway  19  that allows fuel to travel to a fuel injection nozzle  27 . This fuel injection nozzle  27  protrudes into the inside of the combustion chamber  17 . 
     A plurality of embedded wires  29  travel from high voltage terminals  31  mounted on the ceramic sleeve  23  outside and above the cylinder head  15  through the length of the ceramic sleeve  23  including substantially parallel to the lower portion of the fuel injector  21 . These embedded wires  29  extend into the combustion chamber  17  as electrodes  33 . In this embodiment, there are six electrodes  33  arrayed around and below the fuel injector nozzle  27  inside the combustion chamber  17 . All six electrodes  33  are individually connected to high voltage terminals  31  by their own embedded wire  29 . 
     Referring to  FIG. 2 , pressurized fuel is shown entering the fuel injector  21  through the fuel inlet  25 , down fuel passageway  19 , and then out of the fuel injector nozzle  27  into the combustion chamber  17  producing a fuel injection spray pattern  37 . While this is happening, a high voltage discharge  35  occurs between all of the tips of the six electrodes  33  inside the combustion chamber  17 , with the fuel injection spray pattern  37  passing right next to, or through the high voltage discharge  35 . The power for the high voltage discharge  35  that occurs between the six electrodes  33  is produced by a set of six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61  (discussed in detail with reference to  FIGS. 11 and 12 ). 
     A set of six spark plug type high voltage wires  39 ,  41 ,  43 ,  45 ,  47  and  49  connects on one end to the set of six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61 . The other end of the set of six spark plug type high voltage wires  39 ,  41 ,  43 ,  45 ,  47  and  49  have an externally insulated connector  32  that secures and protects the connection to the six high voltage terminals  31  mounted on the upper portion of the ceramic sleeve  23 . This set of six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61  is controlled by a signal generation circuit  63  which has its position in the system discussed in connection with  FIG. 12  and has its operation discussed in detail in connection with  FIG. 9 . 
       FIG. 3A  is a side view of the lower portion of the ceramic sleeve  23  that extends through the cylinder head  15  into the combustion chamber  17 . The fuel injection nozzle  27  at the end of the fuel injector  21  and electrodes  33  are on the end of the ceramic sleeve  23  that faces into the combustion chamber  17 . 
       FIG. 3B  shows the only part of the present invention that is actually exposed to the inside of the combustion chamber  17 . The six electrodes  33  are arranged in a circular manner around the fuel injection nozzle  27 . 
       FIG. 3C  shows the same piece of the present invention that is illustrated by  FIG. 3A  with the difference being that the image was rotated by 90 degrees in order to clarify the shape and position of the electrodes  33  on the end of the ceramic sleeve  23 . 
     An oblique perspective of the lower portion of the ceramic sleeve  23  further illustrates the placement relationship of the fuel injector nozzle  27  to the electrodes  33  in  FIG. 3D . 
       FIGS. 4A ,  4 B and  4 C provide the same set of views as  FIGS. 3A ,  3 B and  3 C the inclusion of the operation of the high voltage discharge  35 . This gives further clarification of the placement of the high voltage discharge  35  upon the electrodes  33  that are arrayed around the fuel injector nozzle  27  on the end of the ceramic sleeve  23  that faces the combustion chamber  17 . This combustion chamber  17  could, within the scope of the present invention, be installed in any of a variety of engine types to include gas turbines as well as reciprocating 2-cycle and 4-cycle diesel or gasoline direct injected internal combustion engines. 
       FIG. 4D  also shows the same oblique perspective view of the lower portion of the ceramic sleeve  23  as shown in  FIG. 3D  with the inclusion of the high voltage discharge  35  occurring between the six electrodes  33 . Other numbers of electrodes to create the Ring-of-Fire are possible. Also, the Ring-of-Fire is schematically illustrated in these figures since it is difficult to illustrate completely. 
       FIGS. 5A ,  5 B,  5 C and  5 D show the lower portion of the ceramic sleeve  23  as shown in  FIGS. 4A ,  4 B,  4 C and  4 D with the inclusion of fuel being injected by a fuel injector  21 . The fuel injection spray pattern  37  of a pintle type of the fuel injector nozzle  27  places a cone of injected fuel centered to the high voltage discharge  35  that occurs between the electrodes  33  inside the combustion chamber  17 . This insures complete combustion initiation of all of the fuel as it is injected. 
       FIGS. 6A ,  6 B,  6 C and  6 D show the lower portion of the ceramic sleeve  23  as shown in  FIGS. 5A ,  5 B,  5 C and  5 D. The difference is that this time the fuel injector  21  has a fuel injector nozzle  27  of the hole type. The hole type fuel injector nozzle  27  produces a fuel injection spray pattern  37  that has a set of lobes. Each lobe sprays directly next to or through the high voltage discharge  35  thus insuring complete combustion initiation of all of the fuel as it is injected into the combustion chamber  17 . 
     Referring to  FIG. 7A , the fuel injector  21  is installed inside the ceramic sleeve  23 . When fuel injection is taking place, a fuel injector pump (not shown) sends pressurized fuel to the fuel inlet  25  of the fuel injector  21  in a manner known in the art. The pressurized fuel travels through fuel passageway  19  to the fuel injector nozzle  27  that injects the fuel into the combustion chamber  17 . The ceramic sleeve  23  surrounds the lower portion of the fuel injector  21 . 
     The upper end of the ceramic sleeve  23  that is above the cylinder head  15  has six high voltage terminals  31  that are connected to six embedded wires  29  that extend from the top to the bottom of the ceramic sleeve  23 . The lower ends of the six embedded wires  29  extend from the bottom of the ceramic sleeve  23  into the combustion chamber  17  as six electrodes  33 . These six electrodes  33  are positioned such that their tips are arranged so that they define a hexagon inside the combustion chamber  17  around and below the fuel injector nozzle  27 . This placement is important to insure that the fuel injection spray pattern  37  from the fuel injector nozzle  27  must pass in close proximity to or through the high voltage discharge  35  that occurs between the tips of the electrodes  33 . 
       FIG. 7B  shows a top view of the fuel injector  21  mounted through the ceramic sleeve  23  with the placement of the six high voltage terminals  31  clearly shown. 
       FIG. 7C  is a view from the combustion chamber  17  looking up at the face of the ceramic sleeve  23  and at the tip of the fuel injector  21  with the fuel injection nozzle  27  in the center of the six electrodes  33 . 
       FIGS. 8A ,  8 B and  8 C are similar views as  FIGS. 7A ,  7 B and  7 C without the fuel injector  21  being shown to further clarify the positions of the high voltage terminals  31 , the embedded wires  29  and the electrodes  33 . 
       FIG. 9  shows the signal generation circuit  63  in detail. The signal generation circuit  63  controls the high voltage generation circuits  51 ,  52 ,  53 ,  55 ,  57 ,  59  and  61 . The signals mentioned in this discussion are shown in detail by  FIGS. 10A ,  10 B and  10 C. 
     The signal generation circuit  63  has its overall output controlled by an engine timing signal source  65  that turns it on and off through an engine timing signal transmission line  67 . The engine timing signal source  65  controls the signal generation circuit  63  so that at the appropriate time, at or before fuel injection is to take place, the high voltage discharge  35  is initiated. The engine timing signal source  65  keeps the high voltage discharge  35  going for as long as necessary to ensure complete combustion of all of the fuel and air mixture inside the combustion chamber  17 . 
     The signal generation circuit  63  has within it a square-wave generator circuit  69  that sends through a square-wave signal transmission line  71 , a square-wave signal  73  to a signal divider circuit  75 . The square-wave generator circuit  63  is based on a 555 timer integrated circuit set up to operate as an astable multi-vibrator circuit producing a square-wave signal between 0 and 5 volts at a frequency between 5 and 30 kilo-hertz. 
     The signal divider circuit  75  divides the square-wave signal  73  into a set of six sequential signals  89 ,  91 ,  93 ,  95 ,  97  and  99 , as shown in  FIG. 10B , that are sent through a set of six sequential signal transmission lines  77 ,  79 ,  81 ,  83 ,  85  and  87  to a signal overlap circuit  101 . The signal divider circuit  75  that divides the square-wave signal  73  into a set of six sequential signals  89 ,  91 ,  93 ,  95 ,  97  and  99  is based on the 4017 decade counter integrated circuit. 
     The signal overlap circuit  101  in turn generates a set of six overlapped sequential signals  115 ,  117 ,  119 ,  121 ,  123  and  125 , as shown in  FIG. 10C , and then sends these signals through a set of six overlapped sequential signal lines  103 ,  105 ,  107 ,  109 ,  111  and  113  to a signal line driver circuit  127 . The signal overlap circuit  101  uses a bank of twelve  1 N 4004  diodes to generate the set of six overlapped sequential signals  115 ,  117 ,  119 ,  121 ,  123  and  125  shown in  FIG. 10C . 
     The signal line driver circuit  127  is activated only when the enable signal from the engine timing signal source  65 , brought in by the engine timing signal transmission line  67  and it allows the set of six overlapped sequential signals  115 ,  117 ,  119 ,  121 ,  123  and  125  to go through the signal line driver circuit  127 . The signal line driver circuit  127  uses a 74HCT541 integrated circuit to act as a “gate” to the set of six overlapped sequential signals  115 ,  117 ,  119 ,  121 ,  123  and  125 . 
     It is within the scope of the present invention to have this engine timing signal source  65  be as simple as a cam-shaft position sensor, such as a Hall-effect sensor, or as complicated as a highly sophisticated engine management computer responding in real time to a number of factors to include actual conditions inside of the combustion chamber  17  as they happen in real time as is known in the art. When enabled by the engine timing signal source  65 , the signal line driver circuit  127  then “cleans up” and strengthens the set of six overlapped sequential signals  115 ,  117 ,  119 ,  121 ,  123  and  125  without otherwise changing them before they are sent out through a set of six control signal output lines  129 ,  131 ,  133 ,  135 ,  137  and  139  to each of the six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61 . 
       FIG. 11  is an electrical schematic for each high voltage discharge circuit  51 ,  53 ,  55 ,  57 ,  59  and  61 . Each of the six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61  is connected to a 24 volt power source  143  and to one of the six control signal output lines  129 ,  131 ,  133 ,  135 ,  137  and  139 . When a signal is received by its intended high voltage discharge circuit  51 ,  53 ,  55 ,  57 ,  59  and  61  it turns on a power MOSFET  145  labeled Q- 1 . In one embodiment of the present invention, the power MOSFET (Metal Oxide Surface Effect Transistor)  145  labeled Q- 1  is a MTY55N20E made by Motorola and it is rated for 55 amps at 200 volts. 
     When the power MOSFET  145  labeled Q- 1  is turned on, a high voltage transformer  147  labeled T- 1  then has current flow from the 24 volt power source  143  through a primary winding power lead  149 . The current passes through a primary winding  151  of the high voltage transformer  147  labeled T- 1 , through a primary winding ground lead  153 , through the power MOSFET  145  labeled Q- 1 , through a resistor  155  labeled R- 1  that is rated at 0.2 ohms and 10 watts, and then finally to a low voltage ground connection  157 . This low voltage ground connection  157  is shared by all of the six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61  and it is also used by all of the components of the signal generation circuit  63 . There is a large value capacitor  159  labeled C- 1  which is rated at 1 microfarad and a small value capacitor  161  labeled C- 2  which is rated at 0.01 microfarads. Both are attached in parallel across the primary winding power lead  149  and the primary winding ground lead  153 . 
     An electrically isolated secondary winding  163  of the high voltage transformer  147  labeled T- 1  has an electrically isolated secondary winding ground lead  165  connected to an electrically isolated “floating” high voltage ground  167  that is shared in the same position of each circuit in all of the six high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61 . The electrically isolated secondary winding  163  of the high voltage transformer  147  labeled T- 1  is connected to an electrically isolated secondary winding high voltage output lead  169 . The electrically isolated secondary winding high voltage output lead  169  is in turn connected to the appropriate one of the set of six spark plug type high voltage wires  39 ,  41 ,  43 ,  45 ,  47  and  49  which in turn are connected to one of the set of six high voltage terminals  31  on the ceramic sleeve  23 . 
       FIG. 12  shows the overall combination of elements of the electrical system according to the present invention. This includes a 5 volt power source  171  used by all of the circuitry inside the signal generation circuit  63 . Further a low voltage ground connection  157  is shown as being shared by all of the high voltage discharge circuits  51 ,  53 ,  55 ,  57 ,  59  and  61  and with the signal generation circuit  63 . 
     It should be appreciated that the other ways of creating and controlling the Ring-of-Fire high voltage discharge  35 . Although any means of creating and controlling the Ring-of-Fire must place it so that the injected fuel spray pattern  37  goes next to or through it as fuel enters the combustion chamber  17 . 
     Referring to  FIG. 13 , the present invention also includes a furnace using the Ring-of-Fire or plasma ball ignition system. The furnace in  FIG. 13  is shown with a plasma ball high voltage power source  200 . The high voltage power source  200  sends out its plasma generating high voltage output through a bundle of six spark plug type high voltage wires  202  to a fuel burner circuitry housing  206  which is mounted on a fuel burner  208 . An ignition control signal wire  204  connects the high voltage power source  200  to the fuel burner control system  332  shown in  FIG. 19  which is inside the fuel burner circuitry housing  206 . It is through the ignition control signal wire  204  that the on/off input for the high voltage source  200  is sent from the fuel burner control system  332 . 
     A burner air tube  216  connects the fuel burner  208  to a furnace  218 . A blower housing  214  brings in fresh air through an air inlet  210  and also brings in recirculated exhaust through a recirculated exhaust outlet  212  from an exhaust gas recirculation pipe  226 . 
     The burner air tube  216  is connected to a furnace boiler  218  which is heated by combustion from the fuel burner  208 . The combustion exhaust gases exit the furnace boiler  218  through a furnace exhaust flue  220 . The exhaust gas recirculation pipe  226  enters the furnace exhaust flue  220  through a hole  224 . The exhaust gas from the furnace exhaust flue  220  enters the exhaust gas recirculation pipe  226  through an exhaust gas recirculation inlet  222 . An exhaust gas recirculation valve  228  can control the amount of exhaust gases recirculated. Although the exhaust recirculation valve  228  shown is as a manual valve, it is also possible to use an automatically controlled valve. 
     Exhaust gas recirculation reduces the amount of oxides of nitrogen formed during combustion by diluting the fresh air entering through the air inlet port  210  with exhaust originally taken from the furnace exhaust flue  220  and conveyed through the exhaust gas recirculation pipe  226  to the blower housing  214 . This creates a measured dilution of the incoming fresh air charge with the exhaust and allows less fuel to be burned for a given volume of gas throughput to the burner  208  while still maintaining the proper fuel to air mixture. This has the overall effect of reducing the temperature at the tip of the combustion flame which is where the oxides of nitrogen are formed. 
     Once the main flow of exhaust gases pass the exhaust system junction, they then pass by an exhaust flue damper  244  before traveling the rest of the way out of the furnace exhaust flue  220  to the atmosphere. 
       FIG. 14  shows a nozzle and igniter assembly that resides inside the burner air tube  216 . When in operation, fuel for the nozzle and igniter assembly arrives through the burner nozzle fuel inlet  246  and then travels through a burner nozzle fuel pipe  248  to a fuel nozzle orifice  250 . There is an electrode insulator mounting bracket  252  mounted to the burner nozzle fuel pipe  248  which holds a set of six plasma generation electrode insulators  256 . Each plasma generation electrode insulators  256  has a plasma generation electrode  258  passing therethrough and the end closest to the fuel burner  208  has a plasma generation electrode terminal  254 . The other end of the electrode  258  has a tip  260 . The tips  260  are preferably evenly spaced around and in front of the fuel nozzle orifice  250 . While six electrodes each having insulators are shown, at least three electrodes are needed to achieve the results of the present invention and more than six electrodes are also possible. 
       FIG. 15  shows the nozzle and igniter assembly mounted inside the burner air tube  216  with the power for the plasma generation coming through the bundle of high voltage wires  202  that are attached to the plasma generation electrode terminals  254 . The other end of the bundle of the high voltage wires  202  is connected to the high voltage power source  200 . On the front end of the air tube  216  is mounted a flame retention plate  264 . The nozzle and igniter assembly has the electrode tips  260  protrude through the flame retention plate  264 . 
     The plasma generation electrode tips  260  are placed in front of the fuel nozzle orifice  250 . In order to prevent unintentional arcing between the plasma generation electrodes  258  and the flame retention plate  264 , a set of plasma generation tip insulators  262  are mounted on the electrode  258  so as to leave the plasma electrode tips  260  exposed to form the plasma. 
       FIG. 16  shows the arrangement of the plasma generation electrodes  260  and their insulators  262  with relation to the flame retention plate  264 . Also clearly shown is how the set of plasma generation tips  260  are arrayed evenly around the fuel nozzle orifice  250 . Also shown is a set of eight flame retention plate air passages  266  which are arrayed radially around the center of the flame retention plate  264 . 
       FIG. 17  is a front end view of the nozzle and igniter assembly with the flame retention plate  264  removed for clarity in order to expose the location of a fuel burner spray nozzle  268 . The fuel burner spray nozzle  268  has the fuel nozzle orifice  250  in the center thereof with the set of six plasma generation electrode tips  260  arrayed radially there around. 
     When the furnace is in operation, the plasma generating high voltage output from the high voltage source  200  is sent through the bundle of high voltage wires  202  to the nozzle and igniter assembly. There each wire from the bundle of high voltage wires  202  is attached to the respective plasma generation electrode terminal  254 . This allows the plasma generating high voltage output to be conducted along the length of the electrodes  258  to the plasma generation electrode tips  260 . 
     At the tips  260 , the plasma generating high voltage output from the high voltage source  200  discharges and thereby forms a plasma ball that all of the fuel spraying out from the fuel nozzle orifice  250  must pass through. 
     The plasma ball is believed to be the main location where the fuel treatment and ignition occur. As best understood, the effect of the plasma ball on the fuel spray that passes therethrough is to remove at least some of the outer valence electrons holding the fuel molecule together. This causes the fuel molecule to break apart into shorter chain hydrocarbons that have also been ionized as a result of passing through the plasma. These ionized shorter chain hydrocarbons not only burn cleaner and more efficiently when compared to longer chain hydrocarbons, the ionized shorter chain hydrocarbons also ignite rapidly upon contact with oxygen due to their ionization state. 
       FIG. 18  shows the schematic diagram of a single high voltage discharge circuit out of the at least three high voltage discharge circuits within the high voltage power source  200 . The number of high voltage discharge circuits is equal to the number of electrodes used in the device. This circuit is controlled through a control signal input line  270  that is connected to the gates of a set of three matching power Metal Oxide Surface Field Effect Transistors (henceforth referred to as MOSFETs)  272 . These three MOSFETs  272  are the switches that when turned on allow current to flow from a 24-volt power source  283  through a primary winding  276  of a high voltage transformer labeled T 1   277 . The three MOSFETs  272  connect the other end of the primary winding  276  to a low voltage ground connection  284  through a 0.2 ohm resistor  285 . Between the low voltage side of the primary winding  276  and low voltage ground  284  are a capacitor of 4700 picofarads  286 , another capacitor of 4700 picofarads  288  and a capacitor of 2200 picofarads  290  and a high amperage diode  282 . When used in this circuit, the high amperage diode  282  acts as a free wheeling diode. 
     Connected across the leads to the primary winding  276  are a capacitor of 0.047 microfarads  292 , a capacitor of 0.1 microfarads  294  and a capacitor of 2200 picofarads  296 . Also attached to the power side of the primary winding  276  connected to the low voltage ground  284  are a capacitor of 4700 picofarads  298 , a capacitor of 2200 picofarads  300 , a capacitor of 0.1 microfarads  302  and a capacitor of 1.0 microfarad  304 . 
     Connected to a secondary winding  278  of the high voltage transformer labeled T 1   277  is a spark plug type high voltage wire  280  that eventually goes to the plasma generation electrode terminal  254  of one of the plasma generation electrodes  258 . The other lead from the secondary winding  278  of the high voltage transformer labeled T 1   277  is an electrically isolated secondary winding ground lead  279  connected to an electrically isolated “floating” high voltage ground  281 . 
     When the power MOSFETs  272  are turned on by an input from a signal generation circuit  330  (shown in  FIG. 19 ) through the control signal input line  270  more than just the electricity from the 24 volt power source  283  flows through the primary winding  276  of the high voltage transformer labeled T- 1   277 . Four capacitors  298 ,  300 ,  302 , and  304  of different values also discharge through the primary winding  276  of the high voltage transformer  277 . 
     These four capacitors  298 ,  300 ,  302 , and  304  also set up a resonant tank circuit with the primary winding  276  which acts as the inductor in the tank circuit. Since each of the four capacitors  298 ,  300 ,  302 , and  304  have a different value, four resonant tank circuits are set up, each one resonating at a different frequency. When the power MOSFETs  272  are turned on, the diode  282  plays an important role in this resonance in that the diode  282  and the power MOSFETs  272  allow current to flow in both directions during resonance through the primary winding  276 . When the power MOSFETs  272  are turned off, resonance can occur for another half cycle through the diode  282 . 
     This does not however stop circuit resonance because at this point the three capacitors  292 ,  294 ,  296  (each of a different value) that are across the leads to the primary winding  276  take over and continue to resonate in the resonant tank circuit they form. Since these three capacitors  292 ,  294 , and  296  all have different values, three different tank circuits are formed that continue to resonate at three different frequencies even after the power MOSFETs  272  are turned off. 
     Also contributing to the collection of various resonant frequencies are the three capacitors  286 ,  288 , and  290  that are connected between the lead of the primary winding  276  opposite its lead connected to the 24 volt power source  283  and the low voltage ground  284 . Although the values of two of the capacitors  286  and  288  are the same, it was determined empirically that this combination produced the most vigorous plasma discharge. 
       FIG. 19  shows how a set of six high voltage discharge circuits  318 ,  320 ,  322 ,  324 ,  326 , and  328  of the type shown in  FIG. 18  are put together inside the high voltage power source  200 . Not only do the individual high voltage power discharge circuits  318 ,  320 ,  322 ,  324 ,  326 , and  328  produce a wide variety of resonance frequencies, these circuits also interact with each other through the electrically isolated “floating” high voltage ground  281 . As a result, all six of the plasma generation electrodes  258  are contributing to the ball of plasma at all times. It is believed that this is a reason why the plasma ball is formed between the set of six electrode tips  260  instead of what would appear to be a circular arc with a hole in it that would allow fuel to pass through without being ionized. 
     When the fuel burner control circuit  232  inside the fuel circuitry housing  206  turns on the fuel burner  208 , the fuel burner control circuit  232  also sends an enable signal through the ignition control signal wire  204  to the signal generation circuit  330 . The other aspects of the circuit in  FIG. 19  are similar to the circuit block diagram shown in  FIG. 12 . The main difference is that the six high voltage outputs go through the high voltage wires  306 ,  308 ,  310 ,  312  and  314  which are grouped together into a bundle of high voltage wires  202 . The wires  202  connect with the nozzle and igniter assembly in the oil burner  208  instead of being connected to an injector-igniter assembly  23  in an internal combustion engine as described in  FIG. 12 . 
     The other major difference is that plasma generation for use in the fuel burner  208  is continuous for as long as it is in operation to provide a flame to the furnace boiler  218 . It is because of this continuous plasma generation that the approach of having three MOSFETs  272  in parallel with each other was adopted in order to reduce heat buildup therein. In order to handle the greater fuel flow rate found in larger furnaces and similar installations it was necessary to develop the improved high voltage discharge circuit design in order to produce a larger and more intense plasma. 
     It is to be understood that although the present invention has been described with regards to preferred embodiments thereof, various other embodiments and variants may occur to those skilled in the art, which are within the scope and spirit of the invention, and such other embodiments and variants are intended to be covered by the following claims.

Technology Classification (CPC): 5