JP6275065B2 - Ignition device - Google Patents

Description

  The present invention relates to an ignition device for an internal combustion engine using dielectric barrier discharge.

  As disclosed in Patent Document 1, in an ignition device using dielectric barrier discharge, studies have been made on an electrode structure for improving ignition performance and a method for controlling an applied voltage. The ignition device disclosed in Patent Document 1 improves the ignitability by generating a dielectric barrier discharge by covering one of the two electrodes with a dielectric and positively generating radicals.

Japanese Patent No. 4924275

  However, since the ignition device disclosed in Patent Document 1 uses dielectric barrier discharge, it is necessary to apply a high-voltage AC waveform. In the high-voltage path from the booster to the ignition plug, Unnecessary discharge occurs for ignition with peripheral devices. This discharge not only reduces the efficiency of ignition energy, but also causes peripheral equipment failure. The failure here is a failure caused by electrical damage due to discharge noise or thermal damage due to discharge. Even when the discharge itself is not generated, the high voltage path from the booster to the spark plug is likely to be a source of electromagnetic waves and noise because it transmits high voltage pulses.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an ignition device that suppresses discharge and radiation noise unnecessary for ignition in a high voltage path from a booster device to a spark plug.

  In order to solve the above-described problems and achieve the object, the present invention includes an AC power source that generates an AC voltage. In order to solve the above-described problems and achieve the object, the present invention includes an ignition plug that is disposed in a combustion chamber of an internal combustion engine and generates a discharge that ignites an air-fuel mixture in the combustion chamber at a discharge voltage. In order to solve the above-described problems and achieve the object, the present invention provides a booster that boosts an AC voltage to a discharge voltage, a concave connection part into which a spark plug is inserted, a booster and a connection part. A barrier discharge coil having an internal wiring connecting the two, an insulator covering at least the connection portion and the internal wiring, and a conductor covering the periphery of the insulator.

  According to the present invention, it is possible to obtain an ignition device that suppresses discharge and radiation noise unnecessary for ignition in a high voltage path from the booster to the spark plug.

Sectional drawing of the gasoline engine to which the ignition device concerning Embodiment 1 of this invention is applied. 1 is a perspective view of an ignition device according to a first embodiment. Sectional drawing which shows the structure of the ignition device concerning Embodiment 1. FIG. 1 is a circuit diagram of an ignition device according to a first embodiment. Sectional drawing which shows another structure of the coil for barrier discharges of the ignition device concerning Embodiment 1. Sectional drawing which shows the structure which abbreviate | omitted the transformation transformer of the coil for barrier discharges of the ignition device concerning Embodiment 1. Sectional drawing which shows the connection part of the coil for barrier discharge of the ignition device concerning Embodiment 1, and a spark plug. The perspective view of the ignition device concerning Embodiment 2 of this invention. Sectional drawing which shows the structure of the ignition device concerning Embodiment 2. FIG. Sectional drawing which shows the structure of the coil for barrier discharge which has a pressure | voltage rise apparatus which has arrange | positioned only the coil for resonance of the ignition device concerning Embodiment 2. FIG. Sectional drawing which shows the structure of the ignition device concerning Embodiment 3 of this invention.

  Hereinafter, an ignition device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a gasoline engine to which an ignition device according to Embodiment 1 of the present invention is applied. FIG. 2 is a perspective view of the ignition device according to the first embodiment. FIG. 3 is a cross-sectional view illustrating the configuration of the ignition device according to the first embodiment. 2 and 3 show a state before the barrier discharge coil 100 and the spark plug 200 are connected. A gasoline engine 67 that is an internal combustion engine includes a combustion chamber 63 in which a mixture of fuel and air burns, an intake valve 64 that opens and closes an intake port of the combustion chamber 63, and an exhaust that opens and closes an exhaust port of the combustion chamber 63. It has a valve 65 and a piston 66 that sucks the air-fuel mixture into the combustion chamber 63, compresses the air-fuel mixture in the combustion chamber 63, and discharges the exhaust gas from the combustion chamber 63. The combustion chamber 63 is provided with a spark plug mounting position 61 where the spark plug 200 is mounted. A plug hole 62 for placing the spark plug 200 is provided above the spark plug mounting position 61. The spark plug mounting position 61 has a female screw shape corresponding to a male screw shape, which will be described later, of the spark plug 200.

  In the first embodiment, the spark plug mounting position 61 is disposed between the intake valve 64 and the exhaust valve 65, but is not limited thereto. Two or more spark plug attachment positions 61 may be provided.

  The gasoline engine 67 opens the intake valve 64 in the intake process to take the air-fuel mixture into the combustion chamber 63, adiabatically compresses the air-fuel mixture with the piston 66 in the compression process, and ignites the air-fuel mixture with the spark plug 200 in the expansion process. Explode and take out output. In the exhaust process, the gasoline engine 67 opens the exhaust valve 65 and pushes the exhaust from the combustion chamber 63 by the piston 66.

  The ignition device 30 includes an AC power source 1 that generates an AC voltage, a spark plug 200 that is disposed in the gasoline engine 67 and generates a discharge for igniting the air-fuel mixture in the combustion chamber 63 using the discharge voltage, and boosts the AC voltage. And a barrier discharge coil 100 provided with a boosting device 40 for performing the above operation.

  The barrier discharge coil 100 includes a connector 2 for connection to the AC power source 1, a transformer 3 that is part of the booster 40, a resonance coil 4 that is part of the booster 40, and a spark plug 200. A concave portion to be inserted and connected to the internal wiring 41 connected to the boosting device 40, the internal wiring 41 connecting the boosting device 40 and the connecting portion 5, the boosting device 40, the internal wiring 41, and the connecting portion. 5 is provided with an insulator 6 that seals 5 and a conductor 7 that covers the insulator 6.

  The barrier discharge coil 100 is a component of the barrier discharge ignition device 30 that suppresses unnecessary discharge that occurs in a high-voltage path during ignition of an air-fuel mixture by barrier discharge and combustion support by radical generation. The booster 40 in the barrier discharge coil 100 is sealed with an insulator 6, and the periphery of the insulator 6 is covered with a conductor 7.

  One end of the barrier discharge coil 100 is connected to the AC power source 1, and the other end is a connection portion 5, and a spark plug 200 is inserted and connected.

  The spark plug 200 includes a connection portion 51 to the barrier discharge coil 100, a first electrode 52 that is a rod-shaped conductor that forms a central electrode, a dielectric 53 that covers the first electrode 52 in all directions, A second electrode 54 which is a peripheral electrode covering all directions, and a hexagonal portion 56 to which torque is applied when being attached to and detached from the spark plug attachment position 61. A dielectric barrier discharge is generated between the one electrode 52 and the second electrode 54.

  In the spark plug 200, the second electrode 54 has a male screw shape so that the spark plug 200 is attached to the spark plug mounting position 61 located at the deepest portion of the plug hole 62 shown in FIG. A hexagonal portion 56 is provided on the upper portion of the housing so as to be attached with a general plug wrench. If the gasoline engine 67 is a general automobile internal combustion engine, the male screw shape of the second electrode 54 is a metric screw of M10 or M12. The spark plug 200 has a structure in which a discharge region 55 located at one end protrudes into the combustion chamber 63 when attached to the spark plug mounting position 61.

  The conductance component of the spark plug 200 generates a reactance-conductance resonance together with the resonance coil 4. That is, when the spark plug 200 is inserted into the connection part 5 of the barrier discharge coil 100, the booster circuit 43 that boosts the AC voltage generated by the AC power source 1 to the discharge voltage together with the transformer 3 and the resonance coil 4. Eggplant.

  The AC power source 1 converts a DC voltage of a battery 71 described later to generate an AC voltage. The AC voltage generated by the AC power supply 1 has an absolute voltage value ranging from 12 V to 500 V and a frequency ranging from 20 kHz to 2 MHz.

  The AC voltage generated by the AC power supply 1 is not limited to a sine wave, and may be a rectangular wave, as long as dielectric barrier discharge is possible.

  FIG. 4 is a circuit diagram of the ignition device according to the first embodiment. The AC power supply 1 is obtained by boosting DC 12V, which is a voltage of a battery 71 of a general automobile, from 2 times to 40 times by a DC-DC converter 72 and then converting it to AC. Conversion from direct current to alternating current is performed by a full bridge circuit 74 using four switching elements 73.

  Although the ignition device 30 according to the first embodiment performs orthogonal transformation by the full bridge circuit 74, a half bridge circuit may be used instead of the full bridge circuit 74. Although the half-bridge circuit can be configured with two switching elements, a double voltage is applied to the switching element even with the same step-up ratio. There is a need to.

  Further, the AC power source 1 can be configured by omitting the DC-DC converter 72. If the DC-DC converter 72 is omitted, the step-up ratio required for the barrier discharge coil 100 increases, and the size of the barrier discharge coil 100 increases. Therefore, from the viewpoint of miniaturization of the barrier discharge coil 100, it is advantageous that the DC-DC converter 72 is not omitted.

  The barrier discharge coil 100 is connected to the AC power source 1 through the connector 2 shown in FIG. The barrier discharge coil 100 is configured such that the resonance coil 4 that is a part of the booster 40 is disposed in the plug hole 62. Therefore, the connector 2 is disposed on the side surface of the conductor 7 in the region above the plug hole 62. The connector 2 may be disposed on the upper surface of the conductor 7 in the region above the plug hole 62.

  When the barrier discharge coil 100 is configured such that a part of the booster 40 is disposed in the plug hole 62, the shape of the booster 40 is geometrically limited by the plug hole 62, but the voltage is maximized. Since the high voltage path after the reactance-conductance resonance is arranged in the plug hole 62, the radiation noise is reduced.

  In the connector 2, the high voltage side output terminal of the AC power supply 1 and the primary side of the transformer 3 are connected. In the connector 2, the ground terminal of the AC power supply 1, the primary side ground terminal of the transformer 3, and the secondary side ground terminal of the transformer 3 are connected. The primary side of the transformer 3 is a low voltage side, and the secondary side of the transformer 3 is a high voltage side.

  The ground of the transformer 3 may be connected to the grounded conductor 7 instead of being taken out from the connector 2. When the ground is taken out from the connector 2, the low voltage side and the high voltage side of the transformer 3 can be separated in order to reduce conduction noise. On the other hand, when the ground is connected to the conductor 7, the ground conductor in the insulator 6 can be shortened, so that the risk of dielectric breakdown with the high voltage region can be reduced.

  The high voltage side of the transformer 3 is connected to one end of the resonance coil 4. The other end of the resonance coil 4 is connected to the spark plug 200.

  The spark plug 200 shown in FIG. 3 has a structure in which at least one of the first electrode 52 and the second electrode 54 is covered with a dielectric 53. A first electrode 52 is passed through the center of the spark plug 200. One end of the first electrode 52 serves as a connection part 51 to the barrier discharge coil 100 connected to the resonance coil 4, and the other end reaches the discharge region 55. Except for the connection portion 51 to the barrier discharge coil 100, the first electrode 52 is covered with a dielectric 53 in all directions. All directions of the dielectric 53 are covered with a second electrode 54 which is a peripheral electrode. Thus, the first electrode 52, the dielectric 53, and the second electrode 54 have a common central axis and are fixed and integrated.

The discharge region 55 is provided with a gap forming a discharge gap between the dielectric 53 and the second electrode 54, and generates a dielectric barrier discharge for igniting the air-fuel mixture. If the gasoline engine 67 is for a general automobile and the metric screw of M10 or M12 is applied to the male screw shape of the second electrode 54, the size of the gap is 0.2 mm to 3 mm. By providing a gap that forms a discharge gap, the thickness of the dielectric 53 is reduced in the discharge region 55. If a metric screw of M10 or M12 is applied to the male screw shape of the second electrode 54, the thickness of the dielectric 53 in the discharge region 55 is 0.1 mm to 5 mm. Although the electrical or mechanical strength of the dielectric 53 decreases as the thickness of the dielectric 53 becomes thinner, the gap between the dielectric 53 and the second electrode 54 becomes larger and the discharge gap can be made longer. , Advantageous for ignition.
On the other hand, increasing the thickness of the dielectric 53 improves the electrical or mechanical strength, but the gap between the dielectric 53 and the second electrode 54 becomes smaller and the discharge gap becomes shorter. Disadvantageous. Further, when the thickness of the dielectric 53 is increased, thermal stress due to a temperature gradient in the radial direction increases in the dielectric 53.

  In portions other than the discharge region 55, the dielectric 53 and the second electrode 54 may be in contact with each other, or an air layer may be present therebetween. The dielectric 53 and the second electrode 54 may be partially in contact with each other, and the ease of heat transfer from the second electrode 54 to the dielectric 53 is changed by adjusting the length of the contact area. The temperature of the spark plug 200 during engine operation can be adjusted. A hexagonal portion 56 is provided on the second electrode 54 of the male thread-shaped portion so that it can be attached with a general plug wrench. Since the hexagonal portion 56 is in contact with the conductor 7, the casing of the gasoline engine 67 including the combustion chamber 63, the second electrode 54 and the conductor 7 are all grounded.

  The barrier discharge coil 100 boosts the voltage in two stages of reactance-conductance resonance using the transformer 3 and the resonance coil 4. After the voltage is boosted by the transformer 3, the AC voltage is further boosted by reactance-conductance resonance between the inductance component of the resonance coil 4 and the capacitance included in the spark plug 200, and protrudes into the combustion chamber 63 of the gasoline engine 67. A dielectric barrier discharge is generated in the discharge region 55 of the spark plug 200. Thus, it is necessary to give the spark plug 200 a certain amount of capacitance, and the spark plug 200 has a structure that can ensure the capacitance. Specifically, the length of the spark plug 200, that is, the first electrode 52 and the second electrode 54 are lengthened to increase the area where both electrodes face each other, or the distance between the first electrode 52 and the second electrode 54 is reduced. As a result, the capacitance of the spark plug 200 is set to about 10 pF to 100 pF. If the drive frequency is set to 500 kHz and the capacity of the spark plug 200 is set to 20 pF, the reactor value at which resonance is obtained is approximately 5 mH. In addition, when the capacity of the spark plug 200 is set to 20 pF and the drive frequency resonates at 50 kHz, the reactor value is approximately 500 mH.

  Considering that the size of the resonance coil 4 increases as the reactor value increases, it is necessary to increase the capacitance of the spark plug 200. When it is difficult to obtain a capacitance with only the spark plug 200, a resonance capacitor is inserted into the barrier discharge coil 100. Specifically, one point is connected between the resonance coil 4 and the spark plug 200, and the other end is grounded via the conductor 7. With the above configuration, an alternating voltage is applied for 0.1 ms to 0.5 ms when igniting. The resonance coil 4 may be an inductance component used for reactance-conductance resonance, and may be leakage inductance due to the transformer 3. In other words, if the booster circuit 43 that realizes reactance-conductance resonance with the leakage inductance of the transformer 3 can be configured, the resonance coil 4 need not be provided.

  FIG. 5 is a cross-sectional view illustrating another configuration of the barrier discharge coil of the ignition device according to the first embodiment. FIG. 5 shows a state before the barrier discharge coil 100 and the spark plug 200 are connected. The barrier discharge coil 100 is configured so that the entire booster device 40 is disposed outside the plug hole 62. By configuring the barrier discharge coil 100 so that the entire booster device 40 is disposed outside the plug hole 62, the booster device 40 is less likely to be geometrically restricted in shape and can be easily designed.

  In the first embodiment, the barrier discharge coil 100 has a two-step boost structure of reactance-conductance resonance using the transformer 3 and the resonance coil 4. It is not necessary to build in. Specifically, the barrier discharge coil 100 can be reduced in size by incorporating a transformer in the AC power source 1. It is also possible to adopt a configuration in which the transformer 3 is omitted. FIG. 6 is a cross-sectional view illustrating a configuration in which the transformer transformer of the barrier discharge coil of the ignition device according to the first embodiment is omitted. FIG. 6 shows a state before the barrier discharge coil 100 and the spark plug 200 are connected. By forming the voltage booster 40 only with the resonance coil 4 and performing voltage boosting only by reactance-conductance resonance using the resonance coil 4 without depending on the transformer, the size of the barrier discharge coil 100 can be reduced. Further, the step-up circuit 43 can be configured by the transformer 3 and the ignition plug 200 by omitting the resonance coil 4.

  In the barrier discharge ignition device 30 according to the first embodiment, the path from the transformer 3 to the discharge region 55 becomes a high voltage, and there is a possibility that an unnecessary discharge is generated for ignition. Unnecessary discharge causes reduction in ignition energy efficiency, electrical damage due to discharge noise of peripheral devices, or thermal damage due to discharge, and thus must be suppressed. When applying DC voltage, the high voltage area need only be covered with an insulator, but when applying AC voltage, which is essential for dielectric barrier discharge, the insulator covering the high voltage area and the peripheral conductor Or barrier discharge will generate | occur | produce between the insulators which covered the conductor. For this reason, in the first embodiment, the insulator 6 in which the booster 40 is molded is covered with the grounded conductor 7 without a gap.

  Specifically, the casing of the barrier discharge coil 100 is made of a metal-like conductor, and the casing itself is used as the conductor 7, and after the pressure booster is disposed inside the conductor 7, the inside is molded with resin. Thus, the insulator 6 is formed. In the barrier discharge coil 100, there is no air layer between the high voltage path and the conductor 7.

  In forming the barrier discharge coil 100, it is necessary to pay attention to dielectric breakdown of the insulator 6. When an electric field exceeding the dielectric breakdown strength of the insulator 6 is formed, the insulator 6 is cracked, and arc discharge occurs between the high voltage path and the conductor 7 through the gap, and the booster 40 ignites. The internal wirings 41 and 42 that are high voltage paths to the plug 200 are melted. For this reason, the insulator 6 needs to ensure a thickness that does not cause dielectric breakdown according to the magnitude of the applied AC voltage. By adopting a structure in which the hexagonal portion 56 and the conductor 7 are in contact with each other, since the barrier discharge coil 100 and the casing of the gasoline engine 67 including the plug hole 62 are configured at the same potential, unnecessary discharge can be suppressed. . By suppressing unnecessary discharge, the efficiency of ignition energy can be improved and electrical and thermal damage to peripheral devices can be prevented.

  A concave connection portion 5 for connection to the spark plug 200 is provided below the barrier discharge coil 100 and connected to a connection portion 51 to the barrier discharge coil 100 located above the spark plug 200. FIG. 7 is a cross-sectional view illustrating a connection portion between the barrier discharge coil and the spark plug of the ignition device according to the first embodiment. FIG. 7 shows a state in which the barrier discharge coil 100 and the spark plug 200 are connected. When the barrier discharge coil 100 or the spark plug 200 is damaged, it is preferable that the connecting portion between the barrier discharge coil 100 and the spark plug 200 is detachable so that only the damaged side can be replaced. However, if an air layer is present at the connection portion, unnecessary discharge occurs, and it is necessary to be able to attach and detach without generating a gap. For this reason, the spark plug 200 is mounted after the grease-like insulator is poured into the concave connection portion 5. When the viscosity of the insulator flowing into the connection portion 5 is low, there is a possibility that an air layer is formed in the connection portion 5 by flowing out of the connection portion 5 after the ignition plug 200 is attached. On the other hand, when the viscosity of the insulator poured into the connection portion 5 is high, bubbles are formed inside the insulator when the spark plug 200 is attached. For this reason, the insulator poured into the connecting portion 5 is selected to have an intermediate viscosity between liquid and solid. If even a slight air layer is present in the connection portion 5, unnecessary discharge is generated. Therefore, it is preferable to use an amount that allows the grease-like insulator to overflow from the connection portion 5 after the ignition plug 200 is attached.

  The uppermost part of the hexagonal part 56 of the spark plug 200 and the lowermost part of the conductor 7 are in contact with each other, and both are electrically connected. However, if a gap is generated in the connecting part 5, unnecessary discharge is generated. 5 and the connecting portion 51 are connected so that a gap is not generated by providing a taper or fitting.

  A method of molding the transformer 3 and the resonance coil 4 with the insulator 6 inside the conductor 7 includes a method in which a resin is poured and hardened. At least any one surface of the conductor 7 is removable in all directions, and is sealed with an adhesive or a screw after molding. Prior to pouring the resin into the conductor 7, it is necessary to dispose the transformer 3 and the resonance coil 4 in the conductor 7 having a shape like a stepped cylinder. In a general automobile engine, dielectric barrier discharge is generated at a voltage of 10 kV to 30 kV. Therefore, in order to prevent the occurrence of dielectric breakdown in the high voltage path, the transformer 3 and the resonance coil 4 and the conductor 7 are used. It is necessary to leave a gap of at least 0.1 mm. Therefore, when molding, a projecting insulator such as plastic is disposed in the conductor 7 to support the transformer 3 and the resonance coil 4. The resin is poured into a conductor 7 in which the transformer 3 and the resonance coil 4 are disposed, and the defoaming operation is performed, so that the transformer 3 and the resonance coil 4 are connected to the insulator 6 inside the conductor 7. Can be molded.

  The internal wiring 41 in the high voltage region inside the conductor 7 contains a resistance component of 100Ω to 20 kΩ, and has an effect of reducing radiation noise. However, it is not always necessary to intentionally provide a resistance component, and if it is not provided, an effect of reducing power consumption can be obtained.

  In the case of a structure in which the barrier discharge coil 100 and the spark plug 200 are integrated and cannot be attached or detached, a curable resin can be used to connect the barrier discharge coil 100 and the spark plug 200, The hexagonal portion 56 can be fixed by welding or soldering. Alternatively, the concave shape of the connecting portion 5 to the spark plug 200 may be a two-stage structure of a cylinder and a hexagonal column, and the hexagonal portion 56 of the spark plug 200 may also be pushed into the insulator 6.

  In any case, when the spark plug 200 is attached to the spark plug mounting position 61 by the male screw shape provided on the second electrode 54, the integrated barrier discharge coil 100 must be rotated together with the spark plug 200. Don't be. For this reason, when the barrier discharge coil 100 and the spark plug 200 are integrated, a mounting jig is provided above the conductor 7. The mounting jig is a hexagonal columnar protrusion or a hexagonal recess. Instead of providing a mounting jig on the conductor 7, the portion of the conductor 7 protruding beyond the plug hole 62 itself may be hexagonal. When the mounting jig is provided on the upper portion of the conductor 7, there is an advantage that the size of the hexagonal columnar protrusion or the hexagonal recess can be freely set. On the other hand, when the upper portion of the conductor 7 is formed in a hexagonal shape, there is an advantage that a mounting jig is not required and the size can be reduced. Note that the mounting jig may have a cross groove so that it can be tightened with a Phillips screwdriver.

  Since the ignition device 30 according to the first embodiment can stably generate a dielectric barrier discharge in the discharge region 55, it can be ignited even when the air-fuel mixture in the combustion chamber 63 is thin. Therefore, the gasoline engine 67 to which the ignition device 30 according to the first embodiment is applied can reduce fuel consumption. Further, the ignition device 30 according to the first embodiment can suppress the discharge and radiation noise unnecessary for ignition in the high voltage path, and can increase the energy transmission efficiency. In addition, the ignition device 30 according to the first embodiment can suppress electrical and thermal damage to peripheral devices.

  In the above description, the insulator 6 seals the booster 40, the internal wirings 41 and 42, and the connection part 5, but covers at least the connection part 5 and the internal wiring 41 to which the discharge voltage is applied. Thus, the effect of suppressing the occurrence of unnecessary discharge and noise can be obtained. That is, by covering at least a part of the booster circuit 43 constituted by at least one of the transformer 3 and the resonance coil 4 and the spark plug 200 with the insulator 6, the effect of suppressing the occurrence of unnecessary discharge and noise can be obtained. can get.

Embodiment 2. FIG.
FIG. 8 is a perspective view of the ignition device according to the second embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating the configuration of the ignition device according to the second embodiment. 8 and 9 show a state before the barrier discharge coil 101 and the spark plug 200 are connected. In the following description, the same reference numerals are given to portions that perform the same functions as those in the first embodiment, and redundant descriptions are omitted.

  As shown in FIG. 8, the ignition device 31 according to the second embodiment includes an AC power supply 1, a barrier discharge coil 101, and an ignition plug 200. The structure of the barrier discharge coil 101 is different from that of the barrier discharge coil 100 of the first embodiment. The AC power source 1 and the spark plug 200 are the same as the ignition device 30 according to the first embodiment. In the first embodiment, the booster 40 including at least one of the transformer 3 and the resonance coil 4 is disposed above the plug hole 62. However, in the second embodiment, the booster 40 is disposed above the plug hole 62. A space for arranging the device 40 is not provided.

  The connector 91 is disposed on the surface of the conductor 7. Since the entire barrier discharge coil 101 is disposed in the plug hole 62, the connector 91 is disposed on the upper surface of the barrier discharge coil 101.

  As shown in FIG. 9, when both the transformer 3 and the resonance coil 4 are arranged in the plug hole 62, the high voltage region is limited to the plug hole 62 and the combustion chamber 63, so that radiation noise is reduced. Is done. This is because the electromagnetic wave generated due to the high voltage is repeatedly reflected and absorbed by the engine casing at the plug hole 62 and the combustion chamber 63, thereby reaching the AC power supply 1 or the engine control unit mounted on the automobile. This is because the electromagnetic wave to be weakened.

  Similarly to the first embodiment, the transformer 3 may be incorporated in the AC power supply 1 and only the resonance coil 4 may be arranged in the booster 40 in the barrier discharge coil 100. FIG. 10 is a cross-sectional view showing a configuration of a barrier discharge coil having a booster device in which only the resonance coil of the ignition device according to the second embodiment is arranged. FIG. 10 shows a state before the barrier discharge coil 101 and the spark plug 200 are connected. In this case, the size of the AC power supply 1 is increased, and a voltage path of 2 kV to 3 kV exists outside the plug hole 62, but the barrier discharge coil 100 can be reduced in size.

  Alternatively, the voltage may be raised only by reactance-conductance resonance using the DC-DC converter 72 of the AC power supply 1 and the resonance coil 4 without using the transformer 3. Reactance-conductance resonance may be performed between the leakage inductance of the transformer 3 and the capacitance of the spark plug 200 without using the resonance coil 4. When the transformer 3 is not used, the voltage step-up ratio required for the AC power source 1 is increased, and when the resonance coil 4 is not used, energy loss is increased. The coil 101 can be miniaturized.

  Since the configurations of the AC power supply 1 and the spark plug 200 are the same as those in the first embodiment, the description thereof is omitted. Connector 91 is a connecting portion between AC power supply 1 and booster 40, and is arranged with a hexagonal shape on the terminal opposite to spark plug 200 in barrier discharge coil 101 of the second embodiment. When the barrier discharge coil 101 and the spark plug 200 cannot be attached and detached, the spark plug 200 and the engine are fixed with screws by turning the connector 91 with a tool such as a plug wrench.

  The ignition device 31 according to the second embodiment can reduce radiation noise as compared with the ignition device 30 according to the first embodiment.

Embodiment 3 FIG.
FIG. 11: is sectional drawing which shows the example of the ignition device concerning Embodiment 3 of this invention. FIG. 11 shows a state before the barrier discharge coil 100 and the spark plug 200 are connected. In the following description, the same reference numerals are given to portions that perform the same functions as those in the first embodiment, and redundant descriptions are omitted.

  The ignition device 32 according to the third embodiment includes an AC power source 1, a barrier discharge coil 102, and a spark plug 200. The structure of the barrier discharge coil 102 is different from that of the barrier discharge coil 100 of the first embodiment. The AC power source 1 and the spark plug 200 are the same as the ignition device 30 according to the first embodiment. The barrier discharge coil 102 is different from the barrier discharge coil 100 of the ignition device 30 according to the first embodiment in the configuration of the conductor 7. In the first embodiment, a metal casing is used to form the conductor 7, but in the third embodiment, an insulator such as plastic is used for the casing. Specifically, as shown in FIG. 11, the insulator 6 and the booster 40 are built in an insulator casing 81, and a conductor is applied or plated on the surface of the casing 81 to form a film-like conductor 7. To do. The conductor 7 needs to have a thickness of 1 μm to 3 mm because unnecessary barrier discharge occurs if a gap occurs in the coating film or plating film of the conductor due to the collision of the scattered matter or the surface corrosion.

  When applying a conductor, the melted metal may be applied directly to the surface, or a sprayed conductor may be applied using a conductive spray. Nickel or copper can be applied as the metal to be applied. When the melted metal is applied to the surface, the temperature becomes high, and thus it is necessary to pay attention to the melting and thermal deterioration of the casing 81. However, it is easy to apply without relatively creating a gap. On the other hand, when applying a spray-like conductor, it can apply | coat at low temperature.

  In the case where the plating film is the conductor 7, since the object to be plated is an insulator, electroless plating is performed. In electroless plating, metals such as copper, nickel, cobalt, silver, and platinum can be plated. Compared with electrolytic plating, plating can be performed uniformly, and holes are not easily generated in the plating film.

  Since the ignition device 32 according to the third embodiment does not require the resin 6 to be poured into the conductor 7 to form the insulator 6, bubbles are generated in the insulator 6 and unnecessary discharge is generated. Can be prevented.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 AC power supply, 2,91 connector, 3 transformer, 4 resonance coil, 5, 51 connection, 6 insulator, 7 conductor, 30, 31, 32 ignition device, 41, 42 internal wiring, 43 booster circuit, 52 1st electrode, 53 Dielectric, 54 2nd electrode, 55 Discharge area, 56 Hexagon part, 61 Spark plug mounting position, 62 Plug hole, 63 Combustion chamber, 64 Intake valve, 65 Exhaust valve, 66 Piston, 67 Gasoline engine , 71 battery, 72 DC-DC converter, 73 switching element, 74 full bridge circuit, 100, 101, 102 barrier discharge coil, 200 spark plug.

Claims (7)

An AC power source for generating AC voltage;
An ignition plug that is disposed in a combustion chamber of an internal combustion engine and generates a discharge that ignites an air-fuel mixture in the combustion chamber at a discharge voltage;
A booster that boosts the AC voltage to the discharge voltage, a concave connection part into which the spark plug is inserted, an internal wiring that connects the booster and the connection part, and at least the connection part and the internal wiring And a barrier discharge coil that includes a conductor that covers the periphery of the insulator without a gap and suppresses the occurrence of barrier discharge between the inside of the insulator and the outside of the insulator. that point the fire apparatus.   2. The ignition device according to claim 1, further comprising a grease-like insulator poured into the connection portion in which the ignition plug is inserted. The spark plug includes a first electrode, a second electrode disposed to face the first electrode, and a dielectric covering at least one of the first electrode and the second electrode,
Ignition device according to claim 1 or 2, characterized in that to generate the dielectric barrier discharge between the first electrode and the second electrode. The ignition device according to any one of claims 1 to 3 , wherein the conductor is a coating film or a plating film formed on a surface of the insulator. The barrier discharge coil has at least one of a transformer and a resonance coil,
At least one with any one of 4 claims 1 to at least a portion of the boosting circuit formed by the said ignition plug is characterized in that it is covered with the insulator of the transformer the transformer and the resonant coil The ignition device described. Wherein at least a portion of the connecting portion between the booster device, any one of claims 1 to 5 being disposed in said plug hole provided in the internal combustion engine in order to place the spark plug Ignition device according to.   An AC power source for generating AC voltage;
  An ignition plug that is disposed in a combustion chamber of an internal combustion engine and generates a discharge that ignites an air-fuel mixture in the combustion chamber at a discharge voltage;
  A booster that boosts the AC voltage to the discharge voltage; an internal wiring that connects the booster and a connection to which the spark plug is connected; an insulator that covers at least the connection and the internal wiring; A conductor that covers the periphery of the insulator without any gap and suppresses the occurrence of barrier discharge between the inside of the insulator and the outside of the insulator, and is connected to the spark plug by a curable resin. An ignition device comprising a coil for barrier discharge.

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