JP2017022211A - Discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge device configured to generate a high voltage in a discharge electrode by generating stable resonance in a step-up transformer.SOLUTION: A discharge device 1 comprises a discharge electrode 20, a pulse oscillation part 30 and a step-up transformer 10 and is configured to generate a high voltage in the discharge electrode 20. The step-up transformer 10 includes two or more cores 11 and 12 forming a gap 13. The gap 13 is configured to form a magnetic path 101a having such magnetic resistance R that a self-resonant frequency fof the step-up transformer 10 becomes higher than a drive frequency fof the step-up transformer 10 and that a coupling coefficient (k) of a primary winding 16 and a secondary winding 17 in the step-up transformer 10 and a resonance quality Q of the step-up transformer 10 become values within a range capable of generating resonance in the step-up transformer 10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a discharge device.

  2. Description of the Related Art As a discharge device provided in an ignition device for an internal combustion engine or the like, there is a discharge device that includes a discharge electrode, a step-up transformer, and a pulse generator, and generates a high voltage using resonance. As a step-up transformer provided in such a discharge device, in Patent Document 1, a gap is provided in the central magnetic leg of the core, and the coupling state between the primary winding and the secondary winding is set to be loosely coupled. Discloses a transformer configured to generate a high voltage.

JP 2000-353627 A

  In such a discharge device, in order to efficiently resonate and obtain a high voltage gain in a high frequency range, it is effective to reduce the magnetic flux leaking from the core in the step-up transformer. Therefore, the core included in the transformer is opened. A closed magnetic path type is preferable to a magnetic path type. However, the closed magnetic circuit type has a larger self-inductance than the open magnetic circuit type, and accordingly, the self-resonant frequency of the step-up transformer is lowered. When the driving frequency of the step-up transformer is in the frequency range from near the self-resonance frequency to greater than the vicinity of the self-resonance frequency, there is a problem that the function is no longer functioning as a transformer due to the influence of the capacitance component. When using resonance in a high frequency range, this problem is likely to occur due to a decrease in the self-resonance frequency.

  In order to solve such a problem, it is conceivable to reduce the self-resonance frequency by reducing the self-inductance by widening the gap provided in the core of the step-up transformer. However, when the core gap is widened, the engagement coefficient k and the resonance quality Q between the primary winding and the secondary winding in the step-up transformer and the resonance quality Q decrease accordingly, and the resonance state in the step-up transformer deteriorates and becomes stable. It becomes difficult to obtain resonance. In particular, when a high frequency region of about 1 MHz is used, the deterioration of the resonance state due to the decrease in the engagement coefficient k and the resonance quality Q becomes remarkable, so that stable resonance is more difficult to obtain.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a discharge device configured to generate stable resonance in a step-up transformer and generate a high voltage in a discharge electrode.

One aspect of the present invention is a discharge device that includes a discharge electrode, a pulse oscillation unit, and a step-up transformer, and generates a high voltage at the discharge electrode.
The step-up transformer has two or more cores arranged so as to form a gap between each other,
The gap is such that the self-resonant frequency of the step-up transformer is larger than the drive frequency of the step-up transformer, the coupling coefficient k between the primary winding and the secondary winding in the step-up transformer, and the resonance quality of the step-up transformer. The discharge device is characterized by forming a magnetic path having a magnetic resistance such that Q is a value within a range in which resonance can occur in the step-up transformer.

  In the above discharge device, a gap is formed in the core of the step-up transformer so that the self-resonant frequency of the step-up transformer is higher than the drive frequency. Thereby, the influence of the capacitive reactance component in the step-up transformer is suppressed, and the function of the step-up transformer is ensured. The step-up transformer has a gap between the cores, and the magnetic resistance in the magnetic path formed in the gap is within the range in which the coupling coefficient k and the resonance quality Q in the step-up transformer can cause resonance in the step-up transformer. ing. Thereby, according to the discharge device, stable resonance can be generated in the step-up transformer, and a high voltage can be generated in the discharge electrode.

  As described above, according to the present invention, it is possible to provide a discharge device configured to generate a stable resonance in a step-up transformer and generate a high voltage in a discharge electrode.

1 is a circuit diagram of a discharge device in Embodiment 1. FIG. FIG. 3 is a cross-sectional view of the step-up transformer in the first embodiment. FIG. 3 is a diagram illustrating a relationship between a gap length and a self-resonant frequency in the first embodiment. FIG. 3 is a diagram illustrating a relationship between a gap length and a kQ value in the first embodiment. The figure which shows the relationship between the length of the gap and the engagement coefficient k in Example 1. FIG. The figure which shows the relationship between the length of a gap and the alternating current resistance value of a step-up transformer in Example 1. FIG. The figure which shows the waveform of the primary voltage and secondary voltage of a step-up transformer in Example 1. FIG. FIG. 3 is a diagram illustrating a voltage gain due to a step-up transformer in the first embodiment. The schematic diagram for demonstrating the structure of the discharge device in Example 1. FIG. Sectional drawing of the core of a step-up transformer in a modification. The figure which shows the structure of the discharge device in Example 2. FIG. FIG. 6 is a schematic diagram for explaining a waveform of a secondary voltage in the second embodiment.

  The discharge device of the present invention can be used as an ignition device provided in a vehicle.

Example 1
Examples of the discharge device will be described with reference to FIGS.
As shown in FIG. 1, the discharge device 1 of this example includes a discharge electrode 20, a pulse oscillation unit 30, and a step-up transformer 10, and is configured to generate a high voltage at the discharge electrode 20.
As shown in FIG. 2, the step-up transformer 10 includes two or more cores 11 and 12 that form a gap 13.
The gap 13 is such that the self-resonant frequency f _s of the step-up transformer 10 is higher than the drive frequency f _{0 of the} step-up transformer 10 and the coupling coefficient k between the primary winding 16 and the secondary winding 17 in the step-up transformer 10. The magnetic field 101a has a magnetic resistance such that the resonance quality Q of the step-up transformer 10 becomes a value within a range in which the step-up transformer 10 can resonate.

Hereinafter, the discharge device 1 of this example will be described in detail.
As shown in FIG. 2, the step-up transformer 10 includes EE type ferrite cores 11 and 12. A primary winding 16 is wound around the central magnetic legs 111 and 121 of the cores 11 and 12 via a bobbin 14, and a secondary winding 17 is wound via a bobbin 15. A gap 13 is formed between the core 11 and the core 12. In this example, the gap 13 is formed in the whole area of the opposing portions of the cores 11 and 12.

The gap 13 is formed by a gap forming member 13 a interposed between the cores 11 and 12. In this example, the gap forming member 13a is formed to have a small magnetic permeability mu _g than the magnetic permeability mu _c of the core 11, 12. The material of the gap forming member 13a can be, for example, resin, wood, ceramic, or the like.

As shown in FIG. 2, the magnetic path 101 a formed in the gap 13 forms a part of the magnetic path 101 formed in the step-up transformer 10. The magnetic resistance R in the magnetic path 101a formed in the gap 13 is defined as follows. That is, the magnetic resistance R has a length of the gap 13 of l _g , an area of the gap 13 (a contact area between the gap forming member 13a and the core 11 or the core 12) S, and a magnetic permeability of the gap forming member 13a. when the mu _g, defined by equation 1 below.

R = l _g / (μ _g S) (Formula 1)

As can be seen from the above equation 1, the magnetic resistance R is a value related to the permeability mu _g of length l _g and the gap forming member 13a of the gap 13. Further, since the magnetic resistance R is related to the self-inductance of the step-up transformer 10, the magnetic resistance R is directly related to the resonance quality Q of the step-up transformer 10.

  Further, the magnetic path 101 a formed in the gap 13 is directly related to the coupling coefficient k between the primary winding 16 and the secondary winding 17 in the step-up transformer 10.

  The resonance state in the step-up transformer 10 can be confirmed by observing the waveforms of the primary voltage and the secondary voltage of the step-up transformer 10. For example, as shown in FIG. 7C, the voltage waveform of a pulse signal emitted from a pulse oscillator 30 described later is a rectangular wave, but is applied to the primary winding 16 as shown in FIG. 7A. If the waveform of the primary voltage changes to a sine wave, it can be determined that the resonance in the step-up transformer 10 is strong and the resonance state is good. When the resonant state of the step-up transformer 10 is good, stable resonance occurs in the step-up transformer 10, so that the secondary voltage is sufficiently boosted as shown in FIG. Will be obtained. On the other hand, if the waveform of the primary voltage remains a rectangular wave, it can be determined that the resonance in the step-up transformer 10 is weak and the resonance state is poor. Then, when the resonance state of the step-up transformer 10 is poor, stable resonance does not occur, so that the secondary voltage is not sufficiently boosted as shown in FIG. 7D, and a high voltage gain cannot be obtained.

  In this example, the coupling coefficient k between the primary winding 16 and the secondary winding 17 in the step-up transformer 10 and the resonance quality Q in the step-up transformer 10 are configured to satisfy kQ ≧ 1. Further, in this example, the coupling coefficient k is configured to be 0.5 or more.

Further, the gap 13 maintains the secondary output power at the drive frequency f ₀ , with the AC resistance value (impedance) measured from the secondary side of the step-up transformer 10 by short-circuiting or opening the primary side of the step-up transformer 10. It can be configured to have a value within a certain range. The AC resistance can be obtained by measuring the output characteristics of the pulse oscillation unit as a voltage source, short-circuiting the primary side of the transformer, connecting probes to both ends of the secondary side, and measuring. Further, the AC resistance can be obtained by measuring the output characteristics of the pulse oscillating unit as a current source, opening the primary side of the transformer, connecting probes to both ends of the secondary side, and measuring.

The AC resistance can be appropriately determined in consideration of the circuit configuration of the discharge device 1 or the like, in the present embodiment, the driving frequency f ₀ and 1 MHz, is set to 3kΩ the AC resistance.
The AC resistance value can be easily obtained by using an impedance analyzer or an LCR meter. In this example, the AC resistance value was obtained by opening the primary side of the transformer using an impedance analyzer (manufactured by NF Circuit Design Block Co., Ltd., model number ZA5405), considering the pulse oscillation unit as a current source.

  In this example, a spark plug is provided as the discharge electrode 20. The spark plug as the discharge electrode 20 includes a center electrode 21 to which a high-voltage secondary voltage output from the step-up transformer 10 is applied, and a ground electrode 22 that is grounded. More specifically, as shown in FIG. 9, the spark plug as the discharge electrode 20 is a so-called creeping discharge plug.

  In the present example, as shown in FIG. 9, the pulse oscillator 30 includes an oscillator 31 and a half bridge circuit 32 connected to the oscillator 31. In this example, the pulse oscillating unit 30 is configured to output a rectangular wave pulse signal.

(Comparative test)
A comparative test was performed on the transformer A, transformer B, and transformer C having the configuration of the step-up transformer 10 shown in FIG. Specific configurations of the transformers A to C are as shown in Table 1.

As shown in Table 1, the gap length l _g (see FIG. 2) in the transformer A is increased stepwise from 0.04 mm to 4 mm, and the gap length l _g in the transformers B and C is increased from 0.04 mm. The size was increased stepwise up to 10 mm. The relationship between the gap length l _g and the self-resonant frequency f _s is shown in FIG. In each of the transformers A through C, as shown in FIG. 3, the self-resonance frequency f _s had become larger as increasing the length l _g of the gap.

Then, as indicated by triangles black circles, black 3, except when the transformer A, B, the length l _g of the gap is less than 0.04 mm, driving the self-resonance frequency f _s It could be a greater state than the frequency f _0. Further, in FIG. 3, the trans C shown in black squares, and the state self-resonance frequency _{f s} is higher than the driving frequency _f 0 (1 MHz) when the length _{l g} of the gap is 0.3mm or more It was.

Then, the product kQ the coupling coefficient k between the resonance quality Q, showing the relation between the length l _g of the resonant state and the gap in Fig. In FIG. 4, in each of the transformers A to C, those confirmed to have a good resonance state are shown in black, and those confirmed to have a bad resonance state are shown in white. Here, “resonance state is good” means that there is sufficient resonance in the step-up transformer 10, and “resonance state is bad” means that there is not enough resonance in the step-up transformer 10. It shall be said. Then, as shown in FIG. 7A, when the waveform of the primary voltage of the step-up transformer 10 changes from a rectangular wave to a sine wave, it is determined that sufficient resonance has occurred, and FIG. As shown, it was determined that sufficient resonance did not occur when the waveform of the primary voltage of the step-up transformer did not change from a rectangular wave to a sine wave.

Then, as shown in FIG. 4, first, in the transformers A through C, as the length l _g of the gap is increased, kQ was smaller. Then, it was confirmed that the resonance state was good in each of the transformers A to C when kQ ≧ 1 was satisfied.

  As shown in FIG. 8, in the transformer B, the voltage gain when kQ = 1.7 is compared with the voltage gain when kQ = 0.6. When kQ = 1.7, kQ = 0. It was shown that a voltage gain about three times higher than in the case of .6 was obtained.

Next, the relationship between the gap length l _g , the coupling coefficient k, and the resonance state is shown in FIG. 5, the trans C shown in trans B and squares indicated by triangles, in the range of length l _g of gaps coupling coefficient k is 0.5 or more, it was shown that the resonance condition is good. Further, the transformer A indicated by a circle, in length l _g whole area of the gap, there is the coupling coefficient k is 0.5 or more, resonant state was good.

Next, FIG. 6 shows the AC resistance in the secondary side of the step-up transformer 10 when opening the primary side of the step-up transformer 10 (impedance), the relationship between the length l _g of the gap. As the AC resistance value increases, the secondary voltage decreases. Then, as shown in FIG. 6, as the length l _g of the gap is large, the AC resistance value tends to substantially decreases. Therefore, to suppress the decrease of the secondary voltage, it is preferable to increase the length l _g of the gap. On the other hand, if the length l _g of the gap is too large, the coupling coefficient k is decreased, rather secondary voltage decreases. In consideration of the relationship between them, the length l _g of the gap is preferably set as the secondary voltage is maintained within a predetermined range. For example, as shown in FIG. 6, the upper limit of the alternating current resistance value so that the 3 k [Omega, it is possible to set the length l _g of the gap. When the magnetic permeability of the gap 13 is substantially mu _{0 (permeability} of vacuum), the length l _g of the gap is the most efficient were getting better at 0.27 mm.

Next, the effect in the discharge apparatus 1 of this example is explained in full detail.
In the discharge device 1 of this example, a gap 13 is formed in the cores 11 and 12 of the step-up transformer 10. Since the gap 13 is formed so that the self-resonant frequency f _s of the step-up transformer 10 is higher than the drive frequency f ₀ , the influence of the capacitive reactance component in the step-up transformer 10 is suppressed. The function as a transformer is ensured. The step-up transformer 10 has a gap 13 between the cores 11 and 12, and the magnetic resistance in the magnetic path 101 a formed in the gap 13 is equal to the coupling coefficient k and the resonance quality Q in the step-up transformer 10. The value is within a range that can cause resonance. Thereby, according to the discharge device 1 of this example, stable resonance can be generated in the step-up transformer 10 and a high voltage can be generated in the discharge electrode 1.

  In this example, the coupling coefficient k and the resonance quality Q satisfy kQ ≧ 1. Thereby, the resonance state including the primary side in the step-up transformer 10 becomes good, and a large voltage gain can be obtained on the secondary side.

  In this example, the coupling coefficient k in the step-up transformer 10 is 0.5 or more. A large voltage gain can be obtained on the secondary side. Thereby, since it is sufficient to set the coupling coefficient k within such a range regardless of the resonance quality Q, it is easy to set the conditions of the discharge device 1 of this example.

Further, in this embodiment, the gap 13, AC resistance value measured from the secondary side of the short-circuit or open to the step-up transformer 10 to the primary side of the step-up transformer 10 (impedance) is the secondary side in the driving frequency f ₀ output It is comprised so that it may become the value of the range by which electric power is maintained. This makes it easy to set the gap 13 in a range where the voltage gain is increased.

Further, in this example, has two or more gap forming member 13a which is interposed to form a gap 13 between the core 11, the magnetic permeability mu _g of the gap forming member 13a is permeable core 11, 12 lower than the permeability μ _c. Thereby, the effective magnetic permeability in the step-up transformer 10 can be reliably reduced by the gap 13, and magnetic energy is easily accumulated in the gap 13. As a result, more stable resonance can be generated in the step-up transformer 10.

  In this example, the discharge electrode 20 forms a spark plug. Thereby, the discharge device 1 of this example can be utilized as an ignition device of an internal combustion engine. In this example, the spark plug as the discharge electrode 20 is a creeping discharge plug. A plasma discharge such as a streamer discharge can be generated by applying a high frequency to the creeping discharge plug. Thereby, long-distance AC arc discharge or glow discharge can be generated using the streamer discharge as a precursor. The spark plug as the discharge electrode 20 used in the present discharge device 1 is not limited to the creeping discharge plug. For example, as a spark plug as the discharge electrode 20 used in the present discharge device 1, a general spark plug having a common ground electrode in which a center electrode and a ground electrode face each other can be adopted. Even in this case, streamer discharge is useful because ionization is promoted in the plug gap between the center electrode and the ground electrode, and spark discharge can be easily generated.

  In this example, the pulse oscillating unit 30 includes an oscillator 31 and a half bridge circuit 32 connected to the oscillator 31. Thereby, since positive and negative voltages can be applied to the step-up transformer 10 without preparing two positive and negative power supplies, high efficiency can be realized without increasing the number of components.

  In this example, the pulse oscillating unit 30 is configured to output a rectangular wave pulse signal. Thereby, since an alternating signal can be easily output as a pulse signal, control of the pulse oscillating unit 30 is facilitated, and resonance is easily generated in the step-up transformer 10 with a simple configuration.

  In this example, the step-up transformer 10 includes cores 11 and 12 and a gap 13 (see FIG. 2). Instead of this, the following modifications may be used. That is, in the first modification, as shown in FIG. 10A, in the gap 13, the central magnetic legs 111 and 121 in the cores 11 and 12 are not provided with the gap forming member 13a, and so-called air gaps are formed. Is formed.

  Further, in the second modification, as shown in FIG. 10B, the gap 13 is not formed in the outer magnetic legs 112 and 122, and the gap 13 is formed only in the central magnetic legs 111 and 121 by the gap forming member 13a. Is formed.

In Modification 3, as shown in FIG. 10C, an extremely thin gap such as a coating, plating, or thin film is formed on the opposing surfaces or at least one of the opposing surfaces of the central magnetic legs 111 and 121 in the cores 11 and 12. A member 13a is provided. Furthermore, an extremely thin gap forming member 13a such as a coating, plating, or thin film is provided on the opposing surfaces or at least one of the opposing surfaces of the outer magnetic legs 112, 122 in the cores 11, 12. These, because the gap 13 is formed, the length l _g of the gap 13 is extremely small.

  In the modified example 4, as shown in FIG. 10 (d), a gap forming member 13 a is provided along the outer walls 113 and 123 of the outer magnetic legs 112 and 122 in the cores 11 and 12. The gap forming member 13 a is provided with a protruding portion 131 a that protrudes so as to be interposed between the opposing surfaces 112 a and 122 a of the outer magnetic legs 112 and 122. The protruding portion 131a protrudes to substantially the center of the opposing surfaces 112a and 122a. The gap 13 formed by the gap forming member 13 a is an air gap in the entire area of the central magnetic legs 111 and 121 and part of the outer magnetic legs 112 and 122.

  In the modified example 5, as shown in FIG. 10E, the central magnetic leg formed by dividing the core 11 of the first embodiment (see FIG. 2) at the base part of the central magnetic leg 111 and the outer magnetic leg 112. 111 and outer magnetic legs 112, and a plate-like portion 114. A gap 18 is formed between the central magnetic leg 111 and the outer magnetic leg 112 and the plate-like portion 114. Therefore, in the modification 5, the gap 13 as the first gap and the gap 18 as the second gap are formed.

  In Modification 6, as shown in FIG. 10 (f), the center magnetic legs 111 and 121 of the cores 11 and 12 are shorter than the outer magnetic legs 113 and 123, and between the center magnetic legs 111 and 121. A central core 19 is provided. And the gap formation member 13a is interposed in the center core 19 and the center magnetic legs 111 and 121, respectively, and the gaps 13 and 18 are formed, respectively.

  In the modified example 7, as shown in FIG. 10G, the gap 13 is not formed in the outer magnetic legs 112 and 122, and the gap 13 is formed only in the central magnetic legs 111 and 121. The gap forming member 13a is not provided between the opposing surfaces of the central magnetic legs 111 and 121, and the gap 13 is an air gap.

In any of the first to seventh modifications, the self-resonant frequency f _s of the step-up transformer 10 is larger than the drive frequency f _{0 of the} step-up transformer 10 and the step-up transformer 10 is the same as in the first embodiment. A magnetic path 101a having a magnetic resistance R such that the coupling coefficient k between the primary winding 16 and the secondary winding 17 and the resonance quality Q of the step-up transformer 10 become values within a range in which the step-up transformer 10 can resonate. By designing the gap 13 (18) so as to achieve the same effect as this example.

  As described above, according to this example, it is possible to provide the discharge device 1 configured to generate a stable resonance in the step-up transformer 10 and generate a high voltage in the discharge electrode 20.

(Example 2)
In this example, as shown in FIG. 11, the discharge device 1 includes high voltage application means 40 that applies a high voltage to the spark plug 20 (discharge electrode) to form an initial discharge. The discharge device 1 is configured to superimpose the high voltage generated by the pulse oscillating unit 30 and the step-up transformer 10 on the spark plug 20 after the initial discharge is generated in the spark plug 20 by the high voltage applying means 40. Yes. In addition, the same code | symbol is attached | subjected to the structural member equivalent to the structural member of Example 1, and the description is abbreviate | omitted.

  In this example, as shown in FIG. 11, the high voltage applying means 40 forms an ignition coil having a transformer 43 having a primary winding 41, a secondary winding 42, and an igniter 44. When the ignition plug 20 is ignited, a negative high voltage is generated on the secondary side of the transformer 43 by the igniter 44, and the high voltage is applied to the center electrode 21 of the ignition plug 20 as indicated by symbol A in FIG. To do. Thereby, a spark discharge as an initial discharge is generated between the center electrode 21 and the ground electrode 22. Thereafter, as shown by a symbol B in FIG. 12, the high voltage generated by the pulse oscillating unit 30 and the step-up transformer 10 is superimposed on the spark plug 20. Thereby, the initial discharge is easily maintained, and the ignitability of the fuel gas is improved.

  In the discharge device 1 having such a configuration, the high voltage applying means 40 is responsible for the formation of the initial discharge, and the pulse oscillation unit 30 and the step-up transformer 10 are responsible for maintaining the initial discharge. Therefore, the required voltage for maintaining the discharge in the pulse oscillating unit 30 and the step-up transformer 10 may be lower than the required voltage for forming the initial discharge in the high voltage applying unit 40. Therefore, the configuration of the pulse oscillation unit 30 and the step-up transformer 10 can be reduced in size. In addition, the discharge device 1 of this example also has the same effects as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Discharge device 10 Step-up transformer 101, 101a Magnetic path 11, 12, 19 Core 13, 18 Gap 13a Gap formation member 16 Primary winding 17 Secondary winding 20 Discharge electrode (ignition plug)
30 Pulse generator 40 High voltage application means

Claims (9)

In a discharge device (1) comprising a discharge electrode (20), a pulse oscillating section (30), and a step-up transformer (10) and generating a high voltage at the discharge electrode (20),
The step-up transformer (10) has two or more cores (11, 12, 19) arranged to form a gap (13, 18) between them,
The gap (13, 18) is such that the self-resonant frequency of the step-up transformer (10) is higher than the drive frequency of the step-up transformer (10) and the primary winding (16) in the step-up transformer (10). And the secondary winding (17) and a magnetic path having a magnetic resistance such that the resonance quality Q of the step-up transformer (10) is a value within a range in which the step-up transformer (10) can resonate. The discharge device (1) is formed so as to form (101a).   The discharge device (1) according to claim 1, wherein the coupling coefficient k and the resonance quality Q satisfy kQ ≧ 1.   The discharge device (1) according to claim 1 or 2, wherein the coupling coefficient k is 0.5 or more.   The gap (13, 18) is such that the impedance measured from the secondary side of the step-up transformer (10) by short-circuiting or opening the primary side of the step-up transformer (10) is the output of the secondary side at the driving frequency. It is comprised so that it may become the value of the range by which electric power is maintained, The discharge device (1) as described in any one of Claims 1-3 characterized by the above-mentioned.   It has a gap forming member (13a) interposed between the two or more cores (11, 12, 19) to form the gap (13, 18), and the magnetic permeability of the gap forming member (13a) is The discharge device (1) according to any one of claims 1 to 4, characterized in that the permeability is lower than the magnetic permeability of the core (11, 12, 19).   The discharge device (1) according to any one of claims 1 to 5, wherein the discharge electrode (20) forms a spark plug.   A high voltage applying means (40) for applying a high voltage to the spark plug to form an initial discharge is provided. After the initial discharge is generated, the high voltage generated by the pulse oscillation unit (30) and the step-up transformer (10) is generated. The discharge device (1) according to claim 6, wherein a voltage is superimposed on the spark plug.   The said pulse oscillation part (30) has an oscillator (31) and a half-bridge circuit (32) connected to this oscillator (31), The Claim 1 characterized by the above-mentioned. Discharge device (1).   The discharge device (1) according to any one of claims 1 to 8, wherein the pulse oscillation unit (30) is configured to output a rectangular wave pulse signal.

Images