MXPA02002937A - Ignition system for stratified fuel mixtures. - Google Patents

Abstract

Systems and methods are shown for igniting fuel in a combustion chamber of an internal combustion engine with at least one internal combustion chamber using a spark ignitor traveling with at least two electrodes. The igniter is accommodated in the combustion chamber such that the ends of the electrodes are substantially flush with the walls of at least one combustion chamber. A first voltage is provided between the electrodes to cause an initial disruptive discharge of a gaseous air / fuel mixture present between the electrodes and, subsequently, a successive commutance that travels between the electrodes after the initial discharge is provided.

Description

IGNITION SYSTEM FOR STRATIFIED COMBUSTIBLE MIXTURES BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention describes the field of ignition systems for internal combustion engines and, more particularly, the field of ignition systems operating on a stratified fuel mixture.

DESCRIPTION OF THE RELATED ART Internal combustion engines are well known. Internal combustion engines typically include at least one combustion chamber within which a gaseous mixture of fuel and air is carried out. The mixture is ignited by means of a spark provided by a spark plug. Conventional spark plugs also typically include a second electrode that is bent over the central electrode to create a distance between the first and second electrodes. When a sufficiently high voltage is created between these two electrodes, a spark gap (spark) occurs between the electrodes. The spark ignites the fuel in the combustion chamber that is located next to the spark. In order for the spark to effectively ignite the fuel, the distance between the electrodes must be inserted far enough into the combustion chamber in such a way that the spark comes into contact with the fuel in the combustion chamber. Fuel can be introduced into the combustion chamber in a large number of ways. One way is by direct fuel injection. Direct fuel injection introduces a fuel pen into a specific part of the combustion chamber. This fuel pen creates a stratification in the combustion chamber. That is, the combustion chamber includes areas where fuel is present (inside the fuel boom) and areas where fuel is not present (the rest of the combustion chamber). In this way, the ignition systems employing direct fuel injection will be referred to below as stratified mixing systems. Another type of fuel supply system that creates, can create a stratified mixture includes an electronic fuel injection system that allows only the entry of air into the chamber for a first period of time and then enters the fuel into the chamber during a second period of time. As previously discussed, it is required to insert a spark plug far enough into a combustion chamber of a motor using a stratified mixing system in such a way that the spark is located in a region of the combustion chamber that is known or that contains the fuel (that is, in the fuel pen).

BRIEF DESCRIPTION OF THE INVENTION The stratified mixture systems discussed above can be considered as engines that have unequally distributed fuel portions. Ideally, an internal combustion engine should have a minimum amount of fuel near the walls of the combustion chamber because the flame produced by the ignition of the fuel boom can be extinguished by the walls of the combustion chamber. When turned off it can result in reduced engine efficiency and higher hydrocarbon emissions.Therefore, great care must be taken in the stratified mix systems present to ensure that the fuel boom is not directed to a location In addition, stratified mixing engines experience other challenges, and one of these challenges is to overcome localized variations in the fuel / air ratio in the fuel boom because of the small size and duration of the spark. Created by a conventional spark plug, if the spark plug is not positioned in a region that has a high fuel / air mixture, the engine may show a misfire., the fuel in the combustion chamber may not ignite. Another related problem is that, even if the fuel ignites, the fuel can only light partially. This may originate due to the fact that stratified mixing systems can produce droplets that are relatively large compared to the homogenized mixture. As these large droplets evaporate, the heat extracted from the system by evaporation can remove the heat from the flame and • extinguish it or reduce the flame. Sometimes this reduces the efficiency of the engine and increases hydrocarbon emissions. In addition, due to the fact that the spark plug needs to be directly in the route of the injected fuel, the spark can be extinguished due to the air current caused by the passage of the fuel. Also, because the spark plug is in the fuel path, the same fuel droplets can extinguish the spark. Stratified mixing systems are also very susceptible to dirt. A spark plug can get dirty due to an accumulation of soot on the spark plug. If the fuel does not burn completely, the resulting soot accumulates in the insulating material on the outside of the spark plug and may result in the spark traveling downward toward the outside of the spark plug rather than between the electrodes. This condition leads to motor misfiring. Any non-uniformity in a combustion chamber leads to incomplete combustion locations and allows hydrocarbons to evaporate and escape into the environment. Placing the spark plug in the combustion chamber leads to said non-uniformities and therefore increases the emissions. The present invention provides an ignition system that effectively ignites layered mixtures without the drawbacks caused by the introduction of conventional spark plugs in a combustion chamber. In one embodiment, the present invention overcomes these drawbacks by providing a spark plug and associated electronics that project a large plasma core into a combustion chamber such that it comes into contact with the stratified fuel. Advantageously, the spark plug does not extend within the combustion chamber nearby, as well as conventional spark plugs and therefore avoids the disadvantages caused by said intrusion in the combustion chamber by the spark plug. In one embodiment, the present invention is directed to an ignition system for use in an internal combustion engine. These modalities include a plasma generating device and associated electronics. A specific type of plasma ejector device is a mobile spark plug (TSI), examples of which are shown in U.S. Patent No. 5,704,321, US patent application and EUA patent application with numbers series 90 / 204,440, which are incorporated in the present invention by reference. In this embodiment, the plasma generating device is mounted in the combustion chamber in such a way that the electrodes of the plasma generating device extend into the combustion chamber in such a way that they do not come into contact with the stratified fuel boom but they continue to expel a volume of plasma in the stratified mixture in such a way that the stratified mixture is ignited. This can be achieved by mounting the plasma generating device in such a way that the electrodes are leveled or nearly leveled with the wall of a combustion chamber. It should be understood that the present invention can be used in non-stratified mixture engines (eg, homogeneous mixture engines) as discussed in more detail below. In another embodiment of the present invention there is shown a method of igniting fuel in a combustion chamber of an internal combustion engine with at least one internal combustion chamber using a mobile spark igniter with at least two electrodes. The method includes accommodating the ignitor in such a way that the ends of the electrodes are substantially flush with the walls of at least one combustion chamber., providing a first voltage between the electrodes to give rise to an initial disruptive discharge of a gaseous / fuel air mixture present between the electrodes and providing a successive current that travels between the electrodes after the initial disruptive discharge. In another embodiment of the present invention, a system for igniting a stratified fuel mixture is shown. The system of this modality includes a mobile spark igniter with at least two electrodes and a circuit to provide first voltage and second voltage between the electrodes to create an initial plasma core and then cause the plasma core to expand and ventilate towards the outer part from the ignitor under a Lorente force. The mobile spark plug ignitor, when used in an engine with a combustion chamber, is arranged in such a way that the ends of the electrodes are substantially flush with a wall of the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments of the invention are illustrated and described below with reference to the accompanying drawings, wherein similar articles are identified by the same reference designation, wherein: Figure 1 is a cross-sectional view of a cylindrical Marshall pistol with an illustration pictorial of its operation, which is useful for the understanding of the invention. Fig. 2 is a cross-sectional view of a cylindrical mobile spark igniter for an embodiment of this invention, taken through the axes of the cylinder, including two electrodes and wherein the plasma produced travels by means of expansion in the direction axial. Figure 3A is a detailed view of the tip of a cylindrical mobile spark ignitor for the embodiment shown in Figure 2. Figure 3B is a detailed view of a tip mode of a cylindrical mobile spark plug ignitor.

Figure 4 is a three-dimensional cross sectional view that further defines an embodiment of the present invention. Figure 5 is a cross-sectional view of a moving spark igniter for another embodiment of the present invention wherein the plasma produced travels by means of expansion in the radial direction. Figure 6 is a pictorial view in section of a mobile spark igniter for a mode of the present invention, such as is installed in a cylinder of an engine. Figure 7 is a pictorial view in section of a mobile spark ignitor for a second embodiment of the present invention, such as is installed in a cylinder of an engine. Figure 8 shows a sectional section view of another mobile spark igniter for one embodiment of the present invention. Figure 9A shows a sectional longitudinal sectional view of another mobile spark igniter for another embodiment of the present invention. Figure 9B is an end view of the mobile spark ignitor of Figure 9A showing the free ends of the opposing electrodes. Figure 9C is an enlarged view of a portion of the figure 9B. Figure 10 is an illustration of the mode of the ignitor of Figure 2 coupled to a schematic diagram of an exemplary electrical ignition circuit for operating the lighter, in accordance with one embodiment of the present invention.

Figure 11 is a high-level block diagram of an ignition circuit according to an embodiment of the present invention. Figure 12 shows a schematic circuit diagram of another ignition circuit mode according to the present invention. Figure 13 shows a modality of the secondary electronics of Figure 11. Figures 14A-14C show alternate modalities of primary electronics of Figure 11. Figures 15A-15C show alternate embodiments of the secondary electronics of Figure 11. Figure 16 shows a high-level block diagram of an electric ignition circuit of the present invention. Figure 17 is a more detailed version of the circuit shown in Figure 16. Figure 18 is a more detailed version of the secondary circuit shown in Figure 17. Figure 19 is a graph depicting an example of the voltage between the electrodes of a Spark plug with respect to the interval that the circuit of Figure 18 can create. Figure 20 is an alternative for the secondary circuit shown in Figure 18. Figure 21 is another alternative for the secondary circuit shown in Figure 18.

Figure 22 is a variation of the circuit shown in the figure 21. Figure 23 is a serially connected version of the circuit shown in Figure 17. Figure 24 is a variation of the circuit shown in the figure 23. Figure 25 is another variation of the ignition circuits of the present invention. Figure 26 is another embodiment of the ignition circuits of the present invention. Figure 27 shows the secondary electronics as included in an addition unit for use in combination with a conventional ignition system. Figure 28 shows how a conventional spark plug can be placed in a combustion chamber. Figure 29 shows how embodiments of the present invention can be placed in a combustion chamber.

DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the invention will describe various embodiments and components of aspects of the present invention. It should be understood that various aspects of the invention may be combined or omitted depending on the context and that the elements required for each embodiment are included only in the appended claims.

I. General Theory of Operation The following analysis will describe the general operation of a plasma generating device to more clearly explain aspects of the present invention. Figure 1 shows a simplified embodiment of a Marshall gun of the prior art (plasma gun) which, with limitation, presents an effective way to create a large volume of plasma. The schematic presentation in figure 1 shows the electric field 2 and the magnetic field 4 in an illustrative Marshall gun, where ?? is the colloidal magnetic field directed along the field line 4. Plasma 16 moves in an outward direction 6 by the action of the force vector Lorentz F and thermal expansion, with new plasma being continuously created by the Disruptive discharge of fresh gas as the discharge continues. Vz is the plasma core velocity vector, also directed in the z direction represented by the arrow 6. In this way, the plasma 16 grows as it moves along and through the spaces between the electrodes 10, 12 (the which are kept in a separate relationship by the insulator or dielectric 14). Once the plasma 16 leaves the electrodes 10, 12, it expands in volume, cooling in the process. Turn on the fuel mixture after it has cooled to the ignition temperature.

Fortunately, the increase in plasma volume is consistent with the recognized strategies to reduce emissions and improve fuel consumption. Both strategies are aimed at increasing the dilution of the gas mixture inside the cylinder and reducing cycle to cycle variations. Dilution of the gas mixture, which is most commonly achieved through the use of either excess air (operating the impoverishment of the engine mixture) or recirculation of exhaust gas (EGR), reduces the formation of nitrogen oxides by decreasing the combustion temperature. Nitrogen oxides play a critical role in the formation of pollution, and their reduction is one of the continuous challenges for the automotive industry. Dilution of the gas mixture also increases fuel efficiency by decreasing temperature and thus reducing heat loss through the walls of the combustion chamber, improving the ratio of specific heats, and by from the reduction of pumping losses to a partial load. Zeilinger determined the formation of nitrogen oxide per horsepower per hour of work performed, as a function of air for the fuel ratio, for three different spark timing (Zeilinger, K., Ph.D. thesis, Technical University of Munich (1994)). He found that both the fuel air radius and the spark timing affect the combustion temperature, and thus the formation of nitrogen oxide. As the fuel mixture or air / fuel ratio (A / F) is diluted with excess air (ie, A / F greater than stoichiometric), the temperature drops. At first, this effect is diminished by the increase in the amount of oxygen. The formation of NOx increases. When the mixture is further diluted, the formation of NOx decreases to values well below those to the stoichiometric mixture because the decrease in the combustion temperature crushes the increase in O2. More advanced spark timing (ie ignition initiation plus degrees before top dead center) increases the maximum temperature and decreases the efficiency of the engine because a larger fraction of the fuel mixture burns before the piston reaches the Top dead center (TDC) and the mixture is compressed at a higher temperature, hence higher NOx levels and heat losses are produced. As the mixture is reduced, the spark timing that provides maximum brake torque (MBT synchronization) increases. The dilution of the mixture results in a reduction of the energy density and the flame propagation velocity, which affects ignition and combustion. The lower energy density reduces the heat released by the chemical reaction within a given volume, and in this way changes the equilibrium between the release of chemical heat and the heat lost to the surrounding gas. If the heat released is less than heat lost, the flame will not spread. Therefore, a larger initial flame is required.

The reduction of the speed of the propagation of the flame increases the duration of combustion. The ignition delay arises as a result of the fact that the front of the flame is very small in the beginning, which causes it to grow very slowly, as the amount of fuel-air mixture ignites is proportional to the area of the surface . The increase in the ignition delay and the duration of combustion leads to an increase in spark advance and to larger variations from cycle to cycle which reduces the output power of the work and increases the roughness of the engine. A larger ignition core will reduce the advance in spark timing required, and in this way the adverse effects associated with that advance will be reduced. (These adverse effects are an increasing difficulty in igniting the fuel mixture, due to the lower temperature and density at the moment of the spark, and an increase in the variation of the ignition delay, which creates feasible conditions for deterioration). The cyclical variations are caused by unavoidable variations in the air ratio for local fuel, temperature, residual gas quantity and turbulence. The effect of these variations on the cylinder pressure is due in large part to its impact on the initial expansion velocity of the flame. This impact can be significantly reduced by providing a spark volume that is greater than the average sizes of the heterogeneities.

A decrease in the cyclical variations of the engine combustion process will reduce emissions and increase efficiency, by reducing the number of poor burn cycles, and by extending the fuel operating air ratio of the engine. While increasing the spark volume, some embodiments of the present invention may also allow the spark to be introduced deeper into the fuel mixture, with the effect of reducing the duration of combustion. To achieve these objectives, some embodiments of the present invention use lighters with relatively short length electrodes with a relatively large distance between them, the distance between the electrodes is large compared to the length of the electrode.

II. Configuration of the plasma generating device (lighters) The following description will explain various aspects of plasma generating device modalities according to the present invention. Figure 2 shows an illustrative embodiment of a TSI 17 according to the present invention. This embodiment has standard mounting means 19 such as filaments for mounting the TSI 17 in a combustion chamber such as a piston chamber of an internal combustion engine. These filaments can mount the TSI in the combustion chamber in such a way that the electrodes extend to specific distances in the combustion chamber. The mounting of the TSI 17 can affect the operation of an internal combustion engine and is discussed in more detail later. The TSI 17 also contains a standard male spark plug connector 21, and insulating material 23. The tip 22 of the TSI 17 varies greatly from a standard spark plug. In one embodiment, the tip 22 includes two electrodes, a first electrode 18 and a second electrode 20. The particular embodiment shown in Figure 2 has the first electrode 18 arranged coaxially within the second electrode 20; that is, the second electrode 20 surrounds the first electrode 8. The first electrode 10 is attached to a distal start connector 21. The space between the electrodes is substantially filled with insulating (or dielectric) material 23. The application of a voltage to the TSI 17 between the first and second electrodes, 18 and 20, causes a discharge originating on the surface of the insulating material 23. The voltage required for a discharge in the insulating material 23 is lower than for a discharge between the electrodes 18 and 20 at a distance from the insulating material 23. Therefore,, the initial discharge occurs in the insulating material 23. The location of the initial discharge should be referred to hereinafter as the "initiation region." This initial discharge constitutes an ionization of the gas (an air / fuel mixture), thereby creating a plasma 24. This plasma 24 is a good conductor and supports a current between the first electrode 18 and the second electrode 20 at a lower voltage than the one required to form the plasma. The current that passes through the plasma serves to ionize even more gas in the plasma. The magnetic fields induced by current that surround the electrode and the current that passes through the plasma interact to produce a Lorentz force in the plasma. This force causes the point of origin of the current that passes through the plasma to move and, in this way, creates a larger volume of plasma. This is in contrast to traditional ignition systems where the ignition region of the spark remains fixed. The Lorentz force created also serves to eject the plasma from TSI 17. The inherent thermal expansion of the plasma aids in this ejection. That is, as the plasma heats up and expands, it is forced to travel towards the outside, away from the surface of the dielectric material 23. The first and second electrodes, 18 and 20, respectively, can be made of materials that can include any suitable conductor such as steel, coating materials, aluminum-plated steel (for erosion resistance or "performance motors"), copper, and high-temperature electrode metals such as molybdenum or tungsten, for example . The electrodes (one or both) can be of a metal with controlled thermal expansion such as Kovar (a registered trademark and product of Carpenter Technology Corp.) and coated with a material such as cuprous oxide to obtain good subsequent adhesions to glass or ceramic. The materials of the electrodes can also be selected to reduce the energy consumption. For example, tungsten treated with torite could be used, and its slight radioactivity could help to pre-ionize the air or air-fuel mixture between the electrodes, possibly reducing the required ignition voltage. Also the electrodes can be made of permanent magnet materials, polarized to help the Lorentz force in the ejection of plasma. The electrodes, except for a few millimeters at their ends, are separated by insulating material 23 which can be an insulator or insulating material which is a high temperature dielectric. This material can be porcelain, cooked porcelain, or a ceramic fired with a varnish, as used in conventional spark plugs, for example. Alternatively, it may be formed of refractory cement, a lab-grade glass ceramic such as Macor (a registered trademark and product of Corning Glass Company), a molded alumina, stabilized zirconia, or the like cooked or adhered to the metal electrodes such as with a soldering glass frit, for example. As mentioned above, the ceramic could also comprise a permanent magnet material such as barium ferrite. It should be appreciated that the second electrode 20 does not necessarily need to be a complete cylinder that completely surrounds the first electrode 18. That is, the second electrode 20 can be removed in such a way that there are spaces separating the pieces from the second electrode 20 of other pieces. These pieces, if connected, would create a complete circle surrounding the first electrode 18.

Figure 3A is a more detailed cross-sectional view of a possible embodiment for the tip 22 shown in Figure 2. The particular embodiment shown in the present invention shows the TSI 17. However, it should be noted that the specific properties of this The configuration could be applied to any of the modalities mentioned later, for example TSI 27, 101 and 120, or to any modality later analyzed. The tip 22, as shown, includes a first electrode 18 and a second electrode 20. Between the first electrode and the second electrode there is an insulating material 23. The insulating material 23 fills a substantial part of the space between the electrodes 18 and 20 The part of the space between the electrodes 18 and 20 not filled by the insulating material 23 hereinafter will be known as the discharge space. This discharge space has a thickness W dg which is the distance between the electrodes 18 and 20 and is measured at the closest point. The length by which the first electrode 18 extends beyond the insulating material 23 is referred to in the present invention as li and the length by which the second electrode 20 extends beyond the insulating material is referred to as l2. The shortest part of li or l2 will be known in the present invention as the length of the discharge space. The first electrode 18 has a radius n and the second electrode 20 has a radius r2. The difference between the radii of the first and second electrodes, r2 - n, represents the width of the discharge space Wg. However, it should be noted that Wg can also be represented by the distance between two separate non-concentric electrodes. The current passing through the first electrode 18 and the plasma 24 to the second electrode 20 creates around the first electrode 18 a colloidal (angular) magnetic field? (I, r), which depends on the current and distance (radii r °, see figure 1) from the axis of the first electrode 18. Therefore, a current I flowing through the plasma 24 perpendicular to the colloidal magnetic field B0 generates a Lorentz force F on the charged particles in the plasma 24 along the z-axis direction of the electrodes 18, 20. The force is calculated approximately as shown in the following equation (1): F ~ I x B · Fz ~ lr.Be This force accelerates the charged particles that, due to the collision with uncharged particles, accelerates all the plasma. Note that the plasma consists of charged particles (electrons and ions), and neutral atoms. The temperature is not high enough in the discharge space to completely ionize all the atoms. The original Marshall guns as a plasma source for fusion devices were operated in a vacuum with a short pulse of gas injection between the electrodes. The plasma created between the electrodes by the discharge of a condenser was accelerated a distance of a dozen centimeters at the final velocity of approximately 107 cm / sec. The strength of 1 Fv entrainment in the plasma is approximately proportional to the square of the plasma velocity, as shown in the following equation (2): Fv ~ vp2 The distance over which the plasma accelerates is short (1-3 mm). In fact, experiments have shown that increasing the length of the acceleration distance of the plasma beyond 1 to 3 mm does not significantly increase the plasma output velocity, even though the electrical energy used to direct said TSI is It increases significantly. At atmospheric pressures and for electric input energy of approximately 300mJ, the average velocity is about 5 x 104 cm / sec. and will be lower at high engine pressure. In a compression ratio of 8: 1, this average speed will be approximately 3 x 104 cm / sec. On the contrary, if more energy is placed in a single discharge of a conventional spark, its intensity increases in some way, but the volume of the created plasma does not increase significantly. In a conventional spark, a much larger fraction of the energy input will heat the electrodes when the conductivity of the discharge path increases. Given the above dimensional constraints, the present invention optimizes the combination of electromagnetic (Lorentz) and thermal expansion forces when the TSI is configured according to the next approximate condition. (r2 - r,) / <; \ x · 1/3 where 1X is the length of the shortest distance of I-i or - It should be noted that the dimensional limits expressed are approximate; small deviations above or below them still provide a functional TSI according to the present invention although probably with less optimal performance. Also, as these dimensions define only the outer limits, a person skilled in the art will realize that there are many configurations that will satisfy these dimensional characteristics. The quantity (r2 - r-i) / 1x represents the space-length relationship in this representation. A smaller space-to-length ratio can increase the Lorentz force that directs the plasma to the outside of the TSI for the same input energy (where there is a higher current due to the lower plasma resistance). If this space-to-length ratio is too small, the additional energy provided by the Lorentz force is primarily due to the erosion of the electrodes due to an increase in the electronic deposition process at the electrodes. In addition, as described above, a TSI that works optimally should form a large volume of plasma. Increasing the space ratio for length for the same electrode length increases the volume where the plasma can be formed and therefore contributes to the increase in the volume of plasma produced. Therefore, the TSI of the present invention preferably has a sufficiently large space-to-length ratio such that there is sufficient volume within which to form plasma. This volume restriction also serves to set a lower limit for the space ratio for length. A space ratio for length of about 1/3 or greater has been noted to create an optimal balance between these two constraints. Contrary to previous attempts where the acceleration of plasma led to the loss of input energy due to the drag forces that grow with the square of velocity, the large space-to-length ratio allows the generation of a large volume of plasma that is ejected at a lower speed. The lower speed reduces the drag force, therefore reducing the input energy that is required. The reduced input energy results in a lower degree of erosion of electrodes, leading, in turn, to a TSI with a duration previously unreachable. Preferably, the TSI ignition system of the present invention employs no more than about 400 mJ per ignition. In contrast, prior Marshall plasma and gun lighters had not attained practical utility because they used much longer ignition energies (eg, 2-10 Joules per ignition), which caused rapid ignition erosion and duration short. Benefits of more efficiency in engine performance were surrounded by an increased power consumption of the ignition system. Figure 3B shows an alternate embodiment of a portion of a tip 22 of a TSI. In this embodiment there is an air space 200 in the direct path on the surface of the insulating material 23 between the first electrode 18 and the second electrode 20. This air space 200 has a thickness Wag and a depth Dag. The Wag thickness and the Dag depth can vary between individual TSIs but are set for each individual TSI. The insulating material in this configuration includes an upper surface 204 and a lower surface 205 located in the lower part of the air space 200. An ignitor with an upper surface 204 and a lower surface 205 as shown in Figure 3B will be referred to in FIG. present invention as a "semi-surface discharge" igniter. It should be noted that a semi-surface discharge ignitor does not require the dimensional relationships shown in Figure 3B. The air space 200 serves several purposes but its dominant effect is to increase the duration of the TSI. First, the air space 200 helps to prevent the electrodes 18 and 20 from short circuits due to the accumulation of a complete conduction route on the insulating material 23. Said driving route can originate from a large number of mechanisms. For example, every time a TSI is turned on, a part of the metal in the electrodes is destroyed. This removal of the metal from the electrodes is known as wear. The wear of the electrodes produces a film of metal deposits on the surface of the insulating material 23. This film, over time, can become solid and thick enough to carry a current and from there to become a driving route. Another way in which a conduction path between the electrodes could be created is due to an excessive accumulation of carbon deposits or the like in the conduction material 204. If the accumulation of carbon deposits becomes large enough to carry a current , a short circuit of the electrodes could originate. This direct interconnection leads to a greater amount of energy applied and consumed by the TSI 17 without an appreciable increase in plasma volume. The air gap 200 provides a physical barrier with which the driving path must be connected before a short-circuit condition occurs. That is, for a short circuit to occur, the air space must be completely connected with metal or carbon or a combination thereof. The air gap 200 also serves to help reduce electrode wear. In the absence of air space 200, the initial discharge occurs between the same points on the electrodes each time the TSI 17 is used to ignite a plasma core. Merely, the initial discharge will occur at a point where the insulating material contacted the second electrode 20 (assuming a discharge from the first electrode 18 to the second electrode 20). Because the discharge occurs at the same point, the second electrode 20 wears more quickly to the point of discharge and eventually is destroyed. The introduction of the air space 200 causes the points of the discharge to vary. By spreading the discharge points on the electrode 20, the wear diffuses on a larger surface; this significantly increases the duration of the electrode. The second electrode 20 is preferably a substantially smooth surface. This allows the spark to jump to more places in the second electrode 20 and thereby increases the area over which the wear occurs. This is shown schematically and is discussed in more detail in the relationship of Figure 4. Figure 4 is an example of a side cut view of one side of a section of the discharge space of a TSI. This example includes the • first electrode 18, the second electrode 20, the insulating material 23 and the air space 200. As discussed above, if the air space 200 did not exist, the initial disruptive discharge point would occur at substantially the same place, that is, the closest point of contact between the second electrode 20 and the insulating material 23. This leads to rapid erosion of the second electrode 20 at that point and limits the duration of the lighter. The air space 200 helps to overcome this problem by varying the location of the initial discharge in such a way that the second electrode 20 does not wear out at the same point at which each discharge occurs. This is shown graphically in Figure 4 where an area of wear 400 is of a thickness of Wa and a height of Ha. The first time the igniter is ignited, the initial flashover will occur at the point when the two electrodes are more close to each other. At that time, some wear of the electrode will occur causing that this point is no longer the nearest point, therefore, the next disruptive discharge will occur at a closer "new" point (assuming a uniform gas mixture). Therefore, the air gap 200 considerably expands the region over which the discharge occurs. When a thin wear ring is formed over the entire perimeter of the second electrode 20, the closest point will be slightly above or below this ring where a new discharge initiation region will be formed. This occurs during the whole period of the lighter. Eventually, the wear area 400 is formed; the size of this area is large enough for the igniter to last a commercially practicable period of time before the second electrode 20 is worn. The thickness of the air gap Wag is limited to being about one-half the thickness of the space of Wag discharge when, this thickness is wider, the effects of the disruptive discharge in the insulating material 23 may be lost due to an increase in the resistance caused by the increase in the space between the electrodes. The wear area, 400, leads to another physical restriction for an ignitor according to one embodiment of the present invention. In the case of concentric cylindrical electrodes, the interior of the second electrode 20 should be substantially smooth to ensure that the distance between the electrodes is substantially the same over the entire length of the discharge space. Particularly, in the vicinity of the upper part of the air space 200, no part of the second electrode 20 should be closer to the first electrode 20 than in any other area of the space. A substantially smooth surface of the second electrode 20 allows the wear of the second electrode 20 to occur around the total wear area 400. At present, those conventional spark plugs are concentric in nature and have a central electrode extending beyond A dielectric material have external electrodes that are not appropriate to take advantage of the Lorentz force. In these conventional spark plugs, the volume of the outer electrode is directed radially (at least to a certain degree) away from the central electrode. To generate Lorentz force in the plasma, the outer electrode must provide a return path for electrical current that is substantially parallel to the central electrode. Thus, in some embodiments, it may be desirable to have the first and second electrodes accommodated such that the front sides of the electrodes remain substantially parallel at least in the initiation region. In other embodiments, the electrodes should be substantially parallel to one another along the length of the discharge space. That is, the first and second electrodes should be parallel to each other from at least one region near the top 204 to the ends of the electrodes. In other embodiments, the first and second electrodes should remain parallel to each other some distance below the upper surface 204. For example, the first and second electrodes may remain parallel to each other a distance below the upper surface 204 which is approximately equal to the thickness of the discharge space Wdg or remain parallel to one another for a distance representing any fraction between zero and one of the thickness of the discharge space Wdg. It should be appreciated that the electrodes of any of the TSI modalities shown in the present invention can also be accommodated in that manner. Referring again to Figure 3B, there could be another space, the expansion space 202, between the insulating material 23 and the first electrode 18. The expansion space 202 has one has an initial thickness, We, when the TSI is cold . In some embodiments, the expansion space 202 exists between the insulating material 23 and the first electrode 18 for almost the entire length of the TSI 17. In other embodiments, the expansion space 202 may exist only between the first electrode 18 and the dielectric material. 23 by a few centimeters (eg .5-5) below the upper surface 204. One purpose of the expansion space 202 is to provide a space in which the first electrode 18 can expand during its heating during the course of the operation. Without the expansion space 202 any expansion of the first electrode 18 could cause the insulating material 23 to break. If the insulating material is broken, its dielectric properties could be altered and therefore, the efficiency of the TSI reduced. In addition, expansion space 202 helps reduce the possibility of short circuits in a manner similar to that of air space 200. However, it should be understood that the embodiment shown in Figure 3B could be implemented without expansion space 202, if a less brittle / more flexible insulating material is discovered. A TSI has been developed that works well with a Wag air gap thickness of approximately 0.53mm, a Dag air gap depth of approximately 5.00mm, and a We expansion space thickness of approximately 0.08mm. These dimensions are • implemented in a concentric TSI electrode similar to TSI 17 of Figure 2 where the length of the first electrode 10 is approximately 2.7mm, the length of the second electrode 20 is approximately 1.2mm and the space between them (-r2) It is approximately 2.4mm. It should be understood that one or both of the air spaces and expansion spaces discussed above can be used in any of the modes of a TSI discussed above. Figure 5 is an example of another embodiment of a TSI according to the present invention. TSI 17 includes a central electrode 25 which is positioned coaxially within the external electrode 28. The space between the electrodes 25 and 28 is substantially filled with an insulating material 23 (e.g., ceramic). A difference between the embodiment of FIG. 5 and the embodiment of FIG. 2 is that there is a flat, disk-like (circular) electrode surface 26 formed integrally with or attached to the free end of the central electrode 25, extending transversely toward a longitudinal axis of the electrode 25 and facing the electrode 28. Note also that the horizontal plane of the disc 26 is parallel to the associated piston head (not shown) when the plasma ignitor 27 is installed in a piston cylinder. The end surface of the electrode 28 facing the disk electrode 26 is a substantially flat circular shape that extends parallel to the front surface of the electrode 26. As a result, an annular cavity 29 is formed between the opposing surfaces of the electrodes 26 and 28. More precisely, there are two substantially parallel surfaces of the electrodes 26 and 28 separated and oriented to be parallel to the top of an associated piston head , in contrast to the embodiment of Figure 2 where the electrodes run perpendicular to an associated piston head when employed. Consider that when the air / fuel mixture is ignited, the associated piston "rises" and is near the spark plug or ignitor 27, so that it is preferable in addition to the space 29 of the ignitor 27 for the wall of the associated cylinder than for the piston head. The essentially parallel electrodes 26 and 28 are positioned substantially parallel to the largest dimension of the volume of the fuel mixture at the time of ignition, instead of being oriented perpendicular to this dimension and towards the piston head as in the embodiment of the Figure 2, and the prior art. It has been found that when the same electrical conditions are used to energize lighters 17 and 27, the plasma acceleration lengths 1 and L, respectively, are substantially equal to obtain optimal plasma production. Also, for TSI 27, under these conditions, the following dimensions work well: the radius of the disc electrode 26 is R2 = 6.8mm, the radius of the insulating ceramic is Ri = 4.3mm and the gap between the electrodes g2 = 1.2mm and the length L = 2.5mm. In the illustrative embodiment of Figure 5, the plasma 32 starts in the discharge space 29 on the exposed surface of the insulator 25, and grows and expands towards the outside in the radial direction of the arrows 29A. This may provide advantages over the TSI embodiment of Figure 2. First, the surface area of the disc electrode 26 exposed to the plasma 32 is substantially equal to that of the final part of the outer electrode 28 exposed to the plasma 32. This means that the erosion of the inner part of the disk electrode 26 can be expected to be significantly less than that of the exposed part of the inner electrode 18 of the TSI 17 of FIG. 2, the latter with a much smaller surface area exposed to the plasma . Secondly, the insulating material 23 in TSI 27 provides an additional heat conduction path for the electrode 26. The aggregate insulating material 23 will keep the inner material of the electrodes 25, 26 cooler than that of the electrode 18. In addition, Using the TSI 27, the plasma will not interfere or erode the associated piston head. Figures 6 and 7 illustrate the differences in plasma trajectories between the TSI 7 of Figure 2 and the TSI 27 of Figure 5 when installed in an engine. In Figure 6, a TSI 17 is mounted on a cylinder head 90, associated with a cylinder 92 and a piston 94 that is reciprocal, i.e., moves up and down, in the cylinder 92. As with any engine conventional internal combustion, as the piston head 96 approaches the top dead center, the TSI 17 will energize. This will produce the plasma 24, which will travel in the direction of the arrow 98 only a short distance to the piston head 96. During this displacement, the plasma 24 will ignite the air / fuel mixture (not shown) in the cylinder 92. The ignition starts in the vicinity of the plasma 24. Unlike this displacement 24, the TSI 27, as shown in Figure 7, allows the plasma 32 to move in the direction of the arrows 100, resulting in the ignition of a larger amount of air / fuel mixture than that provided by TSI 17, as previously explained. A trigger electrode can be added between the inner and outer electrodes of FIGS. 2 to 5 to decrease the voltage required to cause an initial spark current between the first electrode and the second electrode. Figure 8 shows schematically said three-electrode plasma igniter 101. Also, Figure 8 shows a simplified version of the electronics that can drive a TSI. An internal electrode 104 is placed coaxially within the external electrode 106, both with diameters in the order of several millimeters. A third electrode 108 is positioned radially between the inner electrode 104 and the external electrode 106. This third electrode 108 is connected to a higher voltage (HV) coil 110. The third electrode 108 initiates a discharge between the two main electrodes 104. and 106 when loading the exposed surface 114 of the isolator 112. The spaces between the three electrodes 104, 106, 108 are filled with insulating material 112 (e.g., ceramic) except the last 2-3 mm of space between the electrodes 104 and 106 in the combustion end of the ignitor 101. A discharge between the two main electrodes 104 and 106, after initiation by the third electrode 108, begins along the surface 114 of the isolator 112. The gas (air-fuel mixture) ) is ionized by the discharge. This discharge creates a plasma, which becomes a good electrical conductor and allows an increase in the magnitude of the current. The increased current ionizes more gas (air-fuel mixture) and increases the plasma volume, as previously explained. The high voltage between the tip of the third electrode 108 and the external electrode 106 provides a low current discharge, sufficient to create enough charged particles on the surface 114 of the isolator 112 for an initial discharge to occur between the electrodes 104 and 106. As shown in Figures 9A, 9B and 9C, another embodiment of the invention includes a TSI 20 with rod-shaped parallel electrodes 122 and 124. Parallel electrodes 122, 124 have a substantial portion of their respective lengths encapsulated by dielectric insulating material 126, as shown. An upper end of the dielectric 126 retains a spark plug starter 21 which is secured both mechanically and electrically to the upper end of the electrode 122. The dielectric material 126 rigidly retains the electrodes 122 and 124 in parallel, and a part retains rigidly the outer metallic body 128 with mounting filaments 19 around a lower part, such as sample. The electrode 124 is mechanically and electrically secured to the inner wall of the metal body 128 by a rigid assembly 130, as shown, in this example. As shown in Figure 9A, each of the electrodes 122 and 124 extend a distance and fe, respectively, towards the outside of the surface of the lower end of the dielectric 126. With reference to Figures 9B and 9C, the electrodes 122 and 124 may be parallel rods that are spaced a distance G, where G represents the thickness of the discharge space between the electrodes 122, 124 (see FIG. 9C). It has been found that, while operating a TSI as described above, It can generate a lot of RF noise. During the initial high voltage spark gap, the current flows in one direction through a first electrode and in another direction through a second electrode. These opposite flow currents generate RF noise. In conventional spark plugs this is not a problem because a resistive element can be placed inside the spark plug in the input current path. However, due to the large currents experienced during the high current operation stage of the present invention, said solution is not feasible because said resistor would not allow the flow of the current necessary to generate a large plasma core.

Such RF noise can also interfere with various electronic devices and could violate regulations if not adequately protected. As such, and referring again to FIG. 9A, the TSI 120 may also include a coaxial connector 140 for adhering a coaxial cable (not shown) to the TSI 120. The coaxial connector 140 may be filaments, a spring connection or any other appropriate connector to fix a coaxial cable to a cigarette lighter. It should be understood that even when not illustrated in the above embodiment, said coaxial connector 140 could be included in any of the above modalities. In addition, the coaxial connector 140 can be included in any semi-surface ignitor currently available or subsequently manufactured. Cables of this type will generally provide electricity to the starter connector 21, will surround the dielectric 126 and will fit with the body 128 to provide a base. The cable must be able to withstand high voltages (during primary discharge), carry a high current (during secondary discharge) and survive the hostile operating environment in an engine compartment. A suitable coaxial cable is a RG-225 Teflon coaxial cable with double braided protection. Other suitable cables include those shown in PCT published application WO 98/10431, entitled "High Power Spark Plug Wire", filed September 7, 1997, which is incorporated by reference herein.

? III. Ignition Circuit System The following mode will focus on various modes of the ignition circuit system that can lead to an effective utilization of the plasma generating devices shown above. 5 It should be noted that the electronics application of the ignition circuit system shown below can also be applied to other types of spark plugs. Figure 10 shows a TSI 17 with a diagram of the basic elements of an electric or electronic ignition circuit 10 connected thereto, which supplies the voltage and current for the discharge (plasma). (The same circuit system and circuit elements may be used for driving any mode of a TSI shown in the present invention or subsequently manufactured). A discharge between the two electrodes 18 and 20 begins along the surface 56 of the dielectric material 23. The air / fuel gas mixture is ionized by the discharge, creating a plasma 24 which becomes a good current conductor and it allows the passage of current between the electrodes at a lower voltage than that which initiated the plasma. This current ionizes more gas (mixture ? of air / fuel) and increases the volume of the plasma 24. 20 As shown, the discharge is displaced from the first electrode 18 to the second electrode 20. A person skilled in the art will realize that the polarity of the electrodes could be reversed. However, there are advantages when the discharge moves from the first electrode 18 to the second electrode 20. The physical restraints, mainly the fact that the second electrode 20 surrounds the first electrode 18 in this mode, allow the second electrode 20 to have an area of greater total area. The larger the surface area of an electrode, the more resistant it will be to wear. By having the second electrode 20 as the target of the bombardment of positive ions, due to its greater resistance to wear, the production of a TS1 17 with a longer life is allowed. The electrical circuit shown in Figure 10 includes a conventional ignition system 42 (e.g., capacitor discharge ignition (CDI) or transistorized coil ignition (TCI)), a power supply 44 of lower voltage (V2), capacitors 46 and 48, diodes 50 and 52, and a resistor 54. The conventional ignition system 42 provides the high voltage necessary to break the resistance or ionize, the air / fuel mixture in the discharge space along the surface 56 of the dielectric material 23 17. Once the conduction path has been established, the capacitor 46 is quickly discharged through the diode 50, providing a upper current input, or current, in the plasma 24. The diodes 50 and 52 electrically isolate the ignition coil (not shown) from the conventional ignition system 42 from the relatively large capacitor 46 (between 1 and 4 pF). If the diodes 50, 52 were not present, the coil would be unable to produce a high voltage, due to the low impedance provided by the capacitor 46. On the contrary, the coil would charge the capacitor 46. The function of the resistor 54, the capacitor 48 and the voltage source 44 is to recharge the capacitor 46 after a discharge cycle. The use of the resistor 54 is somewhat to avoid a low resistance current path between the voltage source 44 and the TSI burst 17. FIG. 11 is a high-level block diagram of an illustrative embodiment of a circuit ignition 200 according to the present invention. The circuit of this embodiment includes a primary circuit 202, an ignition coil 300 and a secondary circuit 208. In one embodiment, the primary circuit 202 includes a power supply 210. The power supply 210 may be, for example, a converter DC to DC with a 12 volt input and a 400-500 volt output. In other embodiments, the power supply 210 could be a source of oscillating voltage. The primary circuit 202 may also include a charging circuit 212 and a coil driving circuit 214. The charging circuit charges a device, such as a capacitor (not shown), to supply the coil driving circuit 214 with a load for driving the ignition coil 300. In one embodiment, the power supply 210, the charging circuit 212, and the circuit driver 214 may be a CDI circuit. However, it should be understood that these three elements could be combined to form any type of conventional ignition circuit capable of causing a discharge between two electrodes of a spark plug, for example, a TCI system. The coil driver circuit 214 is connected to a low voltage winding of the ignition coil 300.

The high voltage winding of the ignition coil 300 is electrically coupled to the secondary circuit 208. In the embodiment of Figure 11, the secondary circuit 208 includes a spark plug and associated circuit system 220, a second charging circuit 222, and a power supply 224. The spark plug and associated circuit system 220 may include a capacitor (not shown) that is used to store energy in the secondary circuit 208. The two power supplies 210 and 224, for the Primary and secondary circuits 202 and 208, respectively, can come from a single source of energy. It should be noted that the term "spark plug" as used in connection with the next ignition circuit system may refer to any plug capable of producing a plasma, such as the plasma generator device and plasma ejector device described above in Referring to Figure 10. In a commercial application, the circuit of Figure 12 is preferred due to recharge capacitor 46 (Figure 10) in a more efficient energy manner, using a resonant circuit. In addition, the conventional ignition system 42 (Figure 10), whose sole purpose is to create the initial spark current, is modified in such a way that less energy can be used and can be discharged more quickly than a conventional system. Almost all of the ignition energy is provided by the capacitor 46 (Figure 10). The modification is, first, to reduce the high voltage of the inductor coil by using fewer secondary turns.

This is possible because the initiation discharge may be of a lower voltage when the discharge occurs on an insulator surface. The required voltage may be one third of that required to cause a gaseous disruptive current in air for the same distance. Fit the electronic circuit with the parameters of the TSI (length of electrodes, diameters of coaxial cylinders, duration of the • discharge) maximizes the plasma volume when it leaves the TSI for certain storage of electrical energy. By appropriately choosing the parameters of the electronic circuits, it is possible to obtain current and voltage regulation profiles that transfer substantially maximum electrical energy to the plasma. The ignition electronics can be divided into four parts, as shown: the primary and secondary circuits, 202 and 208, respectively, and their associated charging circuits, 212 and 222, respectively. The primary circuit 202 also includes a coil drive circuit 214. The secondary circuit 208 may include spark plug and associated electronic circuit system 220 that can break the resistance in a high voltage section 283, and a low voltage section 285. The primary and secondary circuits, 202 and 208, respectively, correspond to the primary windings 258 and secondary 260 of an ignition coil 300. When the SCR 264 is turned on by applying a trigger signal to its door 265, the capacitor 266 discharge through SCR 264, which causes a current in the primary winding of coil 258. In turn, it imparts a high voltage through the associated secondary winding 260, which causes the gas in a region close to the Spark plug 206 breaks the resistance and forms a conductive path, ie a plasma. Once the plasma is created, the diodes 206 are turned on and the secondary capacitor 270 discharges. After the primary and secondary capacitors 266 and 270, respectively, have discharged, they are recharged by their respective charging circuits 212 and 222. Both charging circuits 212 and 222 incorporate an inductor 272, 274 (respectively) and a diode 276, 278 (respectively), together with an energy supply 210, 224 (respectively). The function of the inductors 272 and 274 is to prevent the power supplies from short circuits through the spark plug 206. The function of the diodes 276 and 278 is to prevent oscillations. The capacitor 284 prevents the voltage V2 of the power supply 224 from passing through large fluctuations. The power supplies 210 and 224 both supply in the order of 500 volts or less at the voltages \ and V2 respectively. They could be combined in a single power supply. The power supplies 210 and 224 can be DC to DC converters of a CDI system (capacity discharge ignition), which can be energized by a 12-volt car electrical system, for example.

The high-current diodes 286 connected in series have a high total counter-disruptive discharge voltage, greater than the maximum spark plug voltage of any of the plasma generating devices shown above, for all engine operating conditions. The function of the diode 286 is to isolate the secondary capacitor 270 from the ignition coil 300, by blocking the secondary winding current 260 to the capacitor 270. If this isolation is not carried out, the secondary voltage of the ignition coil 300 would charge the second condenser 270; and, because of its large capacity, the ignition coil 300 would never be able to develop a voltage high enough to break the resistance of the air / fuel mixture in a region near the spark plug 206. The diode 288 prevents the the capacitor 270 is discharged through the secondary winding 260. Finally, the optimum resistor 290 can be used to reduce the current passing through the secondary winding 260, thereby reducing the electromagnetic radiation (radio noise) emitted by the circuit. Figures 13-15 generally detail several alternate side circuits 208 that can be used in accordance with the present invention. Figure 13 shows an example of a modality of a secondary circuit 208 according to the present invention. The circuit allows a rapid initial spark discharge through the spark plug 206 followed by a slow successive current between the spark plug electrode 206 due to the inductor L1. As such, this circuit can be considered as a "fast-slow" circuit. The secondary winding 260 (high voltage) of the ignition coil 300 receives electrical energy from the primary circuit (not shown), which adheres to the winding on the underside (not shown 9 of the ignition coil 300, to charge the capacitor C1 which is connected in parallel with the ignition coil 300. When the voltage across the capacitor C1 becomes large enough to give rise to a disruptive discharge on the burner 302 and between the electrodes of the spark plug 206, the capacitor C1 is discharge through the spark gap 302 and the spark plug 206. The capacitor C1 is prevented from discharging into the capacitor C2 by the inductor L1 which acts as a great resistance for a rapidly changing current. by the discharge of the capacitor C1 is the initial phase that begins the formation of a plasma core between the electrodes of the spark plug. It should be understood that the burner 302 could be replaced by a diode or other device capable of handling the high voltage passing through the secondary winding 260 and of blocking a large current from being discharged in the secondary winding 260. Occasionally, In the following description and in the appended figures, the burner 302 will be described and displayed as a diode to illustrate its theoretical interchangeability for certain purposes of analysis. Before the disruptive discharge occurs, the capacitor C2 is charged by the power supply 124. The power supply 224 is measured in such a way that it does not create a large amount of voltage in the capacitor C2 capable of causing a disruptive discharge in the spark plug 206. After the condenser has begun to discharge through the spark plug 206. The discharge is a lower voltage, higher current discharge than that provided by the discharge of the capacitor C1. The capacitor C2 is prevented from discharging through the secondary coil 206 by the burner 302. As discussed above, the burner 302 could be replaced by a diode capable of withstanding high voltage across the capacitor C1 and preventing the discharge of high current from capacitor C2 is displaced to secondary winding 260 and at the same time allowing a rapid discharge (for example, a rupture diode or self-fired SCR) The discharge of capacitor C2 through the spark plug 206 is the successive low-voltage, high-current pulse that causes the plasma core to expand and be ejected from the intermediate electrode of the spark plug 206 as described above. The discharge of the capacitor C2 through the spark plug 206 is lower than the discharge of the condenser C1. The reason why the discharge is slower is due to the inductor L1, which serves to decrease the speed at which the capacitor C2 is discharged through the spark plug 206. In one embodiment, the capacitor C2 is larger than the capacitor C2. capacitor C1 and, as is known in the art, its discharge is, therefore, slower. The resistor R1 serves as a current limiting resistor in such a way that the current supply does not provide a direct current through the spark plug 206 after the capacitor C2 has been discharged and limits the charging current for the capacitor C2. It should be appreciated that the connection between the resistor R1 and the power supply 224 is the equivalent Thevenin of a limited power supply of current. It should also be appreciated that the resistor R1 could be replaced with an inductor of appropriate size to prevent a direct current from the power supply 224 from persisting through the spark plug 206 and limiting the charging current from the capacitor C2. The combination of the resistor R1 and the power supply 224 may, from time to time, be referred to in the present invention as a secondary charge circuit. Appropriate values for the components described in relation to figure 13 include C1 = pF, L1 = 200 μ ?, C2 = 2 μ ?, and R1 = 2K ohms, when the power supply provides 500V. Figures 14A-14C show various circuit diagrams for different variations of the primary circuit. All of them use a capacitor 620 which is charged by the primary charging circuit 212 through the primary coil winding 258. All the modes shown in Figures 14A-14C also include an SCR-264 which is used to quickly discharge the capacitor 620 through coil 258, which creates a high voltage in the secondary coil 260. The three circuits have diode 622 in different places. Figure 14A has the SCR 264 parallel with the primary winding 258. Once the capacitor 620 is fully discharged and begins to recharge at the opposite polarity, the diode 264 becomes conductive, and a current through the primary winding 258 continues to through the diode 622 until it is dissipated by the resistances of the primary winding and the diode, 258 and 622 respectively, and the energy transfer to the secondary winding. Therefore, the coil current and secondary voltage (high voltage) do not change polarity. Figure 14B has the diode connected in parallel with the SCR 264. When the SCR 264 turns on, the capacitor 620 discharges, and then recharges at the opposite polarity due to the inductance of the primary coil 258. Once the capacitor 620 is charged At the maximum voltage, the current is reversed, passing through diode 622. This cycle is repeated until all the energy dissipates. Therefore, the coil current and high voltage oscillate. The circuit of Fig. 14C is designed to provide a single pass of current through the primary winding 258, by recharging the capacitor 620 in the opposite direction. The second current passage in the opposite direction occurs through diode 622 and inductor 624 (which are connected in series between the cathode of SCR 264 and the base), at a slow rate, so that the capacitor is recharged after that the spark in the spark plug (not shown) has been extinguished. The diode 622 and the inductor 624 function as an energy recovery circuit. Figures 15A-15C they also show secondary circuit modes 208. The modes shown in Figures 15A-15C include • the spark plug and associated circuit system 220 (Figure 119). The embodiment of Figure 15A includes a single diode 626. It should be noted that the diode 626 could be replaced by a plurality of diodes connected in series The diode 626 provides a lower impedance path for the capacitor 626 to discharge In this modality it is preferable that the two windings 258 and 260, be completely separated. Figure 15B is an example of a direct circuit. This embodiment includes the capacitor C2 which is discharged through the secondary winding 260. Ordinarily, this could result in a very slow discharge due to the high inductance of the secondary winding 260. However, if the coil core 628 becomes saturated, By dramatically reducing the coil inductance, then the discharge can occur more quickly. Figure 15C shows another embodiment of a secondary circuit.

In this embodiment, the inductor 632 is a parallel arrangement with the secondary winding 260. The burner 630 is in series between the secondary winding 260 and the spark plug 206.

In the embodiments described above, the nature of the discharge can be described as having a dual-stage nature. However, in some situations it may be desirable to add a third stage to the download. It has been found that an initial high current interruption may be required to allow the current channel to start to move away from the upper surface of the dielectric material between the electrodes of a plasma generating device. However, if this initial high-energy interruption provides the energy very quickly, the plasma will not move for a sufficient time to create a large nucleus. That is, if the current is large enough to create a Lorentz force sufficient to cause the spark to shift, that current can discharge all the stored energy to quickly allow the spark to move enough to generate an elongated plasma core. In addition, large currents lead to increased electrode wear. These drawbacks can be alleviated by lengthening the discharge or decreasing the amount of current for a given load. However, if the current is reduced to achieve a longer discharge, the resulting Lorentz force may not be strong enough to cause the spark to move away from the location where the spark originated (eg, the upper surface of the dielectric). ). The following examples analyze several circuits that overcome these problems, and others, by combining the initial spark gap with a high current fast discharge to get the spark to shift and lengthen the lower current discharge to increase the plasma core while minimizing electrode wear Figure 16 shows an example which hereinafter should be known as an ignition system of three parallel circuits 700. This system includes a conventional high voltage circuit 702, a secondary circuit 704 and a third circuit 706. The high voltage circuit 702 and the secondary circuit 704 are connected in parallel with the spark plug 206. The parallel connection is similar to those described above. The high voltage circuit 702 can be any conventional ignition circuit such as a CDI circuit, a TCI circuit or a magnet ignition system. The high voltage circuit 702 provides the initial high voltage to ionize the air / fuel mixture in the discharge space of a plasma generating device. In the following examples, it should be understood that the high-voltage circuit includes primary and secondary windings of the ignition coil. Secondary circuit 704 provides a successive current that serves to expand the plasma core. The embodiment of Figure 16 also includes a third circuit 706 connected to the secondary circuit 704. In some embodiment, the third circuit 706 may be a subcircuit of the secondary circuit 704. The third circuit 706 provides an initial pulse of current during the successive current that Move away from the upper surface of the dielectric to the initial current channel (and the surrounding plasma).

Figure 17 shows a more detailed example of the circuit shown in Figure 16. This circuit includes a high voltage circuit 702, secondary circuit 704 and third circuit 706. First capacitor C1 is connected in parallel with high voltage circuit 702 The function of the first capacitor C1 is to enhance the initial spark between the electrodes of the spark plug 206 by providing a high voltage, fast discharge. In some embodiments, the first capacitor C1 can be omitted. For the purposes of this analysis, the combination of capacitor C1 and the circuit High voltage should be referred to as the primary circuit 708. The primary circuit 708 may also include a first subcircuit SC1 connected between the capacitor C1 and the spark plug 206. The first subcircuit SC1 may be a device capable of preventing the capacitors of the second circuit 704 and the third circuit 706 are discharged into the first capacitor C1 after the capacitor C1 has been discharged. An additional feature of the first subcircuit SC1 may be that it reduces the propagation time of the high voltage. Suitable elements that can be used for the first subcircuit SC1 include, but are not limited to, diodes, rupture diodes and spark plugs. The secondary circuit 704 includes a second capacitor C2, and inductor L, and the second subcircuit SC2. Attached to the second circuit 704 is the secondary charger 710 which includes the resistor R1 and the voltage supply 224.

The inductor L1 serves to decrease the discharge of the second capacitor C2. As discussed below, this allows voltages of three desired stages to produce a plasma growth. The second subcircuit SC2 serves to isolate the secondary circuit 704 from the high voltage created in the primary circuit 708 to protect the secondary circuit 704 as well as to provide a higher impedance to force the primary circuit 708 to generate a voltage high enough to originate an initial spark gap between the electrodes of the spark plug 206. At this end, the second subcircuit SC2 may be a high voltage diode or an inductor. . The third circuit 706 includes a third capacitor C3 connected in parallel with the spark plug 206. The third circuit 706 may optionally also include a third subcircuit SC3. The third capacitor C3 provides an initial pulse of current, which allows the plasma to move away from the initial disruptive discharge region. The third optional subcircuit SC3 can be used to prevent rapid recharging of the third capacitor C3. If the third subcircuit SC3 is omitted, the third capacitor C3 can form an oscillatory circuit with the second capacitor C2 and the inductor L1. The possible implementation of the third subcircuit SC3 includes, but is not limited to, a diode connected in parallel with an inductor or a resistor or simply a single diode. Of course, the diode would be connected in such a way that its anode is connected to the third capacitor C3 and its cathode is connected to the inductor L1.

Figure 18 shows another embodiment of a secondary circuit 208. This circuit provides a high initial "spring" voltage through the spark plug 206 followed by a first high current discharge and a slower discharge. Figure 18 will be used to explain the operation of a three-stage circuit. As previously discussed, the high voltage circuit (not shown) provides power to the secondary coil 260 of the ignition coil 300. When the voltage in the secondary coil 260 exceeds the spark gap voltage between the spark plug electrodes of ignition 206, an initial discharge of a high voltage occurs between the electrodes. In this embodiment, the first and second subcircuits have been replaced by diodes D1 and D2. The initial voltage discharged into the spark plug 206 may be on the 500V scale. Therefore, diode D1 should be able to sustain a voltage drop of about 500V. However, 500V is provided as an example only and like a person skilled in the art will realize that this voltage could be higher or lower depending on the application. The initial high voltage has several functions. First, this high voltage can help eliminate any deposit of carbon and / or metal present between the electrodes of the spark plug 206. In addition, this high voltage may be forming the plasma core. During the period in which the primary circuit is charging the coil 300, the power supply 224 is charging the capacitors C3 and C2. The diode D2 prevents the secondary coil 260 from discharging through the capacitor C3 or capacitor C2. After the initial discharge of the secondary coil 260 through the spark plug 206, both capacitors C2 and C3 start to discharge through the spark plug 206. The discharge of the capacitor C3 is a fast discharge compared to the discharge of the condenser C2 due to the inductor L1 that is placed between the two. Therefore, the capacitor C3 provides a rapid discharge of high current through the spark plug 206 which serves to give rise to the plasma core between the electrodes of the spark plug 206 to expand and move outwards between the electrodes . Due to the inductor L1, the discharge of the capacitor C2 is slower than that of the capacitor C3 and sustains a current between the electrode even after the capacitor C3 has been discharged. The capacitor C2 is prevented from discharging through, and in this way charge the capacitor C3 blocking the diode D3. Figure 19 is a graph of voltage at the electrodes of the spark plug 206 as a function of time. From the interval t to the interval t-i the voltage at the electrodes of the spark plug 206 increases as the voltage of the secondary coil 260 increases up to the time ti. In the ti interval, the voltage has increased to the level where a spark gap can occur between the spark plug electrodes 206. Furthermore, because there is no inductor between the capacitor C3 and the spark plug, the condensate C3 also begins to discharge which is added to the current through the spark plug and leads "spring" on the electrodes. The secondary coil 260 and the capacitor C3 are allowed to discharge freely. Therefore, the voltage falls rapidly between the interval ti and t2. In the interval t2, the capacitor C2 (whose discharge was delayed due to the inductor L1) starts to discharge to | through the spark plug 206. The combined discharges of the secondary winding 260 and of the capacitors C2 and C3 are taken into account for the surface equality of the voltage curve between intervals 2 and Í3. At the time of the interval t3, the capacitor C3 and the secondary winding 260 have been completely discharged and the capacitor C2 is allowed to discharge itself and provide a current through the plasma between the electrode for a long period of time (it is say, until it is completely discharged or a new cycle begins). Appropriate values for the circuit components in the figure 18 have been found to be C2 = 2 \ iF, C3 = 0.2MF, L1 = μ ?, and R1 = 2K ohms with the power supply 224 supplying 500V. It should be understood that the above functional explanation can be applied to any of the three-stage circuits described in the present invention. Figure 20 shows another embodiment of a secondary circuit 208. This embodiment is substantially the same as that discussed in relation to Figure 18 with the addition of the third subcircuit SC3. In this example, the third subcircuit SC3 includes a diode D3 connected in parallel with an inductor L3. The cathode of diode D3 is connected between D2 and L1 and its anode is connected to capacitor C3. C1 has been omitted for clarification but may be included as observed by one skilled in the art. Figure 21 shows a circuit similar to that of Figure 18 except that the diodes D1 and D2 have been replaced, respectively, by a spark gap 712 and an inductor L2. This mode works in much the same way as in Figure 18. The burner 712 provides an impedance such that C3 and C2 are not discharged in the secondary coil 260 or are loaded in C1 instead of the spark plug 206 and the inductor L2 provides a similar impedance to prevent the voltage of secondary coil 260 from charging capacitors C2 and C3 instead of being discharged into the electrodes of spark plug 206. Inductor L2 provides this functionality due to the inherent characteristics of the inductors as well as the characteristic frequency of the disruptive discharge in the burner 712. The inductor 12 must be of a size that provides a sufficiently high impedance at the characteristic frequency of the air gap disruption (approximately 10 MHz) at the same time that continues to allow C3 and C2 to be downloaded through L2. In some embodiments, burst 712 may be replaced by solid state elements operating in manners similar to the burner such as a burst diode or a self-firing SCR. In other aspects of the multistage discharge is the same as described above.

Of course, and as shown in Figure 22, the secondary circuit could include the third subcircuit SC3 described above. In the embodiment of Figure 22, the third subcircuit SC3 includes a diode D3 connected in parallel with an inductor L3 where the cathode of the diode D3 is connected between D2 and L1 and its anode is connected to the capacitor C3. Of course, SC3 could only include diode D3. Figure 23 is an alternative embodiment of a circuit that provides a three-stage discharge through the spark plug 206. In this embodiment, a conventional high-voltage circuit 702 can be connected directly to the spark plug 206. This diode Lock 720 is connected between the output terminals 722 and 724 of the high voltage circuit 702 and serves to prevent the high voltage from charging the capacitors C2 and C3. The capacitor C3 is connected between the anode of the blocking diode 720 and the base. Connected in parallel with capacitor C3 is the series connection of inductor L1 and capacitor C3. After the initial disruptive discharge between the spark plug electrodes 206 caused by the high voltage of the conventional high voltage circuit 702, as described above, C3 is rapidly discharged through the spark plug 206 while the discharge of C2 becomes slower due to inductor L1. The discharge in this mode is similar to that shown in Fig. 19. Of course, and as mentioned above, the circuit of Fig. 23 also includes a charging circuit 726 for charging capacitors C2 and C3 before each discharge.

Figure 24 shows a modality similar to that shown in Figure 23 with the addition of the third subcircuit SC3. In this embodiment, a diode D3 connected in parallel with an inductor L3 is included where the cathode of the diode D3 connected between D2 and L1 and its anode is connected to the capacitor C3. Figure 25 is an example of another embodiment of a secondary circuit 208 according to the present invention. This modality differs from the previous modalities in at least two aspects. First, this mode does not use a spark gap or diode to prevent the capacitor C2 of the secondary circuit 208 from being charged by the voltage found in the secondary winding 260 of the ignition coil 300. Second, the power supply 210 of the circuit primary 202 supplies an oscillating voltage. In one embodiment, the power supply 210 may oscillate at an RF frequency. The ignition coil 300 in this case has a primary winding 402 that gives less turns than the secondary winding 260. In a preferred embodiment, the secondary winding 260 of the ignition coil 300 has an auto resonance approximately equal to the oscillation frequency f0 of the oscillating power supply 210. Due to the primary winding 402 of the ignition coil 300 gives less turns than the secondary winding, its resonant frequency does not match that of the oscillating power supply 210. As such, a capacitor C5 of suitable size is used to accommodate the primary winding 402 at the resonant frequency of the oscillating power supply 210. Therefore, at the node 404 there is a high oscillating voltage. The diode D1, as previously discussed, avoids the discharge of the capacitor C2 in the secondary winding 260. The diode D1 also serves as a half-wave rectifier. However, as one skilled in the art will realize, the diode D1 could be replaced with a capacitor which will transmit the entire oscillating signal at the same time that it continues to block the DC discharge of the capacitor C2. In contrast to the previous modes already discussed, the voltage in winding 260 is prevented from being discharged into capacitor C2 by means of a parallel connection of inductor L1 and capacitor C4 instead of a diode. The inductor L1 preferably has a high Q factor which allows it to provide, theoretically, infinite impedance at its resonant frequency. The capacitor C4 is used to tune the inductor L1 in such a way that its resonant frequency matches that of the oscillating power supply 210. In this way, the oscillating voltage is prevented from passing through the capacitor C2. As discussed above, when the voltage at the node 404 exceeds the spark-gap voltage at the spark plug electrodes 206, the secondary winding 260 is discharged through the spark plug electrodes 206. The capacitor C2 provides the successive current that causes the plasma core to expand and be expelled from between the electrodes of the spark plug 206. The parallel combination of the capacitor C4 and inductor L1 does not affect the discharge of the capacitor C2 because its discharge is performed at a lower frequency. Figure 26 shows another alternative mode circuitry that can be used to provide a multi-stage discharge to a plasma ejecting device. This embodiment includes a first transformer 730 which is usually part of a high voltage ignition system. Connected and in parallel with the secondary side 732 of the first transformer 730 is a compensation capacitor 734. The compensation capacitor 734 is connected in parallel with the series connection of a spark gap 736 and the primary side 738 of a second transformer 740 In one embodiment, the second transformer 740 is a toroidal transformer (eg, metal core) with a higher number of turns on its secondary side 742 than on the primary side 738 (eg, a ratio of turns of 4 to 1). may be appropriate) When a sufficient voltage is stored in the compensation capacitor 734, a rapid disruptive discharge in the burner 736 may occur. The rapid burst induces a high voltage on the secondary side 742 of the secondary transformer 740. The high voltage induced on the secondary side 742 causes initial disruptive discharge between the electrodes of the spark plug 206 that is connected between a first secondary side terminal 744 742 and the base. Connected between the second terminal 746 on the secondary side 748 and the base is a third capacitor C3. The third capacitor C3 is connected in parallel with the series combination of the inductor L1 and the capacitor C2. A charging circuit 748 may be connected at the point between the inductor L1 and the capacitor C2 to charge capacitors C2 and C3 (said charging circuit, as mentioned above, can include a power source and a resistor, the resistor connected at the point between the inductor L1 and the capacitor C2). After the initial disruptive discharge between the spark plug electrode 206, the capacitors C3 and C2 start to discharge (for example, the current begins to flow from them) through a secondary side 742 of the second transformer 742 towards the spark plug of ignition 206. The current passing through the secondary side 742 causes the core of the second transformer 740 to saturate and therefore reduce the effective impedance of the secondary side 742. As mentioned above, the inductor L1 slows down the discharge of the capacitor C2 to create a discharge through the spark plug 206 similar to that shown in Fig. 19. In one embodiment, the first and second side, 732 and 742 respectively, should be placed in such a way that in the current induced in the secondary side 742 due to the initial spark gap flows in the same direction as the discharge of the capacitors C2 and C3. This avoids having to reverse the magnetic field in the core and therefore avoids the losses associated with said coating. Examples of component values described in relation to figure 26 are C1 = 200pF, C2 = 2.2MF, C3 = 0.67? and L1 = 200MF.

IV. Addition units Any of the above described secondary circuit modes can be implemented as an addition unit to be used in conjunction with a conventional ignition system installed in an internal combustion engine to allow said engines to operate a plasma generating device of a effective way. For example, and now referring to Figure 27, the secondary circuit 208 could be completely encapsulated in a small package that is connected to the output of the primary electronics (circuits) 202 (which could be any conventional ignition system and, as sample, includes ignition coil 300). In one embodiment, the addition unit includes the two diodes D1 and D2 or alternatively, burners mentioned above may be provided instead. Between the diode cathodes D1 and D2 is the spark plug 206. The successive current producer 602 may contain any of the aforementioned secondary circuits as seen on the right side of the blocking elements D2. It should be noted that D2 can be replaced by the parallel LC combination shown above if the primary electronics uses an alternating voltage source. In addition, the power supply 224 could be co-located or receive power from the primary electronics power source. In one embodiment, the secondary electronics 208 can be turned off to allow the primary electronics only to control the spark plug. This may be advantageous for some engine operating conditions. For example, when the engine is running at RPM due to the fuel / air mixture provided by a carburetor at these speeds. Therefore, switch 604 can be opened when it is determined that the motor is operating at sufficient RPM to obtain a good mixture and a successive voltage is not required to create a larger plasma core.

V. Placement of a plasma generating device in a combustion chamber Optimal placement of an ignitor will be analyzed in relation to figures 26 and 27 below. Generally, when operating systems containing stratified mixtures, the igniter should be mounted in the combustion chamber in such a way that it does not come into contact with the fuel pen introduced into the combustion chamber, but rather, eject the plasma in the pen of fuel from a certain distance. Figure 28 is an example of a conventional ignition installation for an internal combustion engine. A fuel injector 802 periodically injects a fuel pen 804 into a combustion chamber 806. After the fuel pen 804 has been injected, the combustion chamber 806 contains a mixture layered with a fuel-rich region (the fuel 804) and a region without a substantial amount 808 of fuel. A spark plug such as the conventional spark plug 810 ignites the fuel pen 804 by creating an electrical discharge (spark) between the first electrode 812 and a second electrode 814. The spark causes the fuel pen 804 to ignite and direct the piston 816 in a downward direction. As mentioned above, there are several problems associated with such a system. Primarily, the location of the fuel boom 804 must be directed such that there is a minimum amount of fuel near the walls of the combustion chamber 806 to prevent the flame from being extinguished by the walls of the combustion chamber 806. In addition, the discharge between the first and second electrodes 812 and 814 must be positioned in such a way that it comes into contact with the fuel pen 804 or the fuel pen 804 will not ignite. Placing the electrodes 812 and 814 directly in the path of the fuel boom 804 could lead to the spark igniting due to the passage of the fuel or to the creation of a significant amount of dirt in the spark plug 810. Figure 29 shows through of example, a way to avoid these problems that are generated by using the teachings contained in the present invention. As mentioned above, the fuel injector 802 injects a layered mixture (ie, a fuel boom 804) into the combustion chamber 806. Therefore, the combustion chamber 806 includes a layered mixture of the fuel boom 804 and a region 808 that does not contain a significant amount of 'fuel. It should be noted that the fuel injector can introduce the fuel boom 804 into the combustion chamber 806 by a variety of methods, such as direct fuel injection. A plasma generating device 820 is displaced in the combustion chamber in such a way that the ends of its electrodes 822 and 824 are level or almost level with the wall of the combustion chamber 106. In one embodiment, the end of the electrode more large 822 or 824 extends less than about 2.54 cm. in the camera 10 combustion 806. In other embodiments, the electrodes may extend from any distance between approximately 0 and 2.4 cm. in the combustion chamber 806. The plasma generating device 820 generates a volume of plasma 832, as described above, which is ejected from between the electrodes 822 and 824 in the fuel pen 804 and ignites the 15 fuel booster 804. Said system allows the designer of the ignition system to integrate a plasma generating device that is level or almost level with an optimized combustion chamber. Instead of extending the range of the spark plug (and incurring many of the aforementioned problems) in the ignition pen 804, a mode 20 of the present invention utilizes a combination of special dual energy electronics 830 (as described above) and a plasma generating device appropriately designed to form a plasma 832 and inject it into the fuel boom 804.

At high speeds, the engines generally operate in a homogeneous mixing mode of operation where the fuel injector injects the fuel boom 804 into the combustion chamber 806 at an early stage of the cycle to provide uniform mixing throughout the combustion chamber 806, when the combustion starts near the top dead center of the engine cycle. The ignition system of the present invention shows advantages in this mode as well. First, the plasma generating device 820 can be level or nearly level with the cylinder wall, which reduces the hydrocarbon emissions and partial burnout that results from the ignition of the spark near the outgoing spark plugs. Second, the plasma generating device 820 is by design a spark plug "cold", eliminating potential pre-ignition problems that result from the outgoing spark plug designs used in current stratified mix engines. Third, the present invention allows the combustion chamber to be designed more optimally for higher speed performance. Finally, the present invention, in some embodiments, can be operated in a conventional manner (as opposed to the dual stage mode discussed above). In these modalities, the system may include a deactivating element (either external or internal, possibly inherent to the electronics) to control the application of the TSI operation against conventional operation, depending on which operating areas require a current ignition core. higher. The deactivating element serves to deactivate the successive power supply (for example, secondary electronics) or, alternatively, prevent the current generated in the supply from being discharged through the igniter. In any case, the net effect is to prevent the successive current from being transmitted to the lighter. The system can exchange modes based on engine RPM, regulation position, the level at which the RPM changes, or any available engine condition that could give information on how well the fuel is mixed. A simple way to implement such a system includes, with reference to Figure 27 to exemplify only, include an additional element (such as a thyristor) between the part of the circuit that generates the successive current (for example, to the left of D2) that it only allows access to the next part when the element is active. Said element, in effect, blocks the current of the successive current provider. Alternately, and as previously discussed, the switch 604 could serve to disconnect the successive current generator when said successive current is not required. Whether the switch 604 or the additional element, as one may realize, can be controlled by a circuit that determines the best mode of operation depending on the operating conditions mentioned above, like others. Having described some modalities, it should be apparent to those skilled in the art that the foregoing is primarily illustrative and not limiting, having been presented only as an example.

Numerous modifications and other modalities are included in the scope of a person skilled in the art and likewise are contemplated in the scope of the invention.

Claims (1)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A method of igniting a heterogeneous mixture in a combustion system that includes an ignitor with at least two electrodes, the method comprises: introducing a fuel pen into the combustion system in such a way that the heterogeneous fuel and air mixture exists in the combustion system; provide a voltage between the electrodes that creates an initial plasma core and subsequently causes the plasma core to expand and be expelled to the outside of the ignitor under a Lorentz force, characterized by: accommodating the ignitor in the combustion system in such a way that the ends of the electrodes remain at the edge of the fuel boom in at least one stratified charge operation condition of the combustion system. 2. The method according to claim 1, further characterized in that the step of the assembly includes mounting the ignitor in such a way that the plasma core is expelled from the igniter towards the fuel boom. 3. The method according to claim 1 or 2, further characterized in that the combustion system is a motor. 4. A system for igniting a stratified fuel mixture in a combustion system comprising: an ignitor with at least two electrodes and a circuit for supplying a voltage between the electrodes s that creates an initial plasma nucleus and subsequently causes the The plasma core expands and is expelled to the outside of the igniter under a Lorentz force, characterized by: where the lighter, is arranged in such a way that the ends of the electrodes are on the edge of a pen or in the stratified mixture in at least one operating condition 'of the combustion system. 5. - The system according to claim 4, further characterized in that said electrodes are accommodated 10 longitudinally and approximately parallel to one another and the minimum length V of said electrodes is such that it allows the plasma to move along the electrodes away from a region of initiation of discharge under the effect of the Lorentz force. 6. - The system according to claim 4, further characterized in that said electrodes are concentric cylinders. 7. - The system according to claim 4, further characterized in that the discharge surfaces of said electrodes are placed substantially parallel to one another from a location that is at least one half of a thickness of space of 20 discharge below the surface of electrically insulating material at one end of the shorter part of said electrodes. 8. - The system according to claim 4, further characterized in that the discharge surfaces of the electrodes are placed substantially parallel to one another from a location that is at least a thickness of discharge space below the material surface electrically insulating at one end of the shorter part of said electrodes. 9. The system according to claim 4, further characterized in that it also comprises a third electrode arranged between the first and second electrode. 10. - The system according to claim 9, further characterized in that the first voltage is applied between the third electrode and the second electrode and a second voltage is applied between the first electrode and the second electrode. 11. - The system according to claim 4 or 9, further characterized in that a total energy supplied to the igniter is less than about 400mJ per discharge. 12. The system according to claim 4 or 9, further characterized in that the ignition circuit provides a total energy to the ignitor by discharge of less than about 1% of the available energy of the lit mixture. 13. The system according to claim 4 or 9, further characterized in that it also includes means for mounting the ignitor in the combustion system in such a way that, when mounted, the electrodes of the ignitor are on the wall of a system of combustion. 14. - The system according to claims 4 - 13, further characterized in that it also comprises means for holding the ignitor to the circuit by means of a coaxial connection.