Ignition coil and ignition device

Abstract

Provided is a technique whereby heat generated from two primary coils of a single ignition coil can be efficiently dissipated to the outside of a case. An ignition coil (104) housed in a housing has a first through core (61), a second through core (62), an outer peripheral core (63) on one end side, and an outer peripheral core (64) on the other end side. A first through core (61) penetrates the inside of the first primary coil and the inside of the first secondary coil (L12). A second through core (62) passes through the inside of the second primary coil and the inside of the second secondary coil (L22). The one-end-side outer peripheral iron core (63) connects one end of the first through iron core (61) and one end of the second through iron core (62). The other-end-side outer peripheral iron core (64) connects the other end of the first through iron core (61) and the other end of the second through iron core (62). The housing has a concave shape that opens upward and is filled with a molding resin. The upper end of the one-end-side outer peripheral iron core (63) and the upper end of the other-end-side outer peripheral iron core (64) are located above the first secondary coil (L12) and the second secondary coil (L22), respectively.

Description

Technical Field

[0001] This invention relates to an ignition coil for an internal combustion engine and an ignition device having the ignition coil. Background Technology

[0002] In the past, in internal combustion engines such as automobiles, lean combustion, where the proportion of fuel is lower than the stoichiometric air-fuel ratio, was sometimes used to improve fuel economy in response to resource depletion. Furthermore, in response to global warming and to achieve a decarbonized society, the use of carbon-free ammonia as fuel has been studied. However, these fuels are generally less flammable than gasoline, requiring high energy to ignite. Therefore, to enable efficient combustion of these fuels, various ignition methods have been studied, such as multi-point ignition systems that involve multiple consecutive discharges in the spark plug, and DCO (dualcoil offset) ignition systems that continuously discharge the spark plug by alternately operating two ignition coils connected to it. For example, ignition devices for internal combustion engines employing the DCO ignition system are disclosed in Patent Documents 1 and 2.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-129464

[0006] Patent Document 2: Japanese Patent Application No. 2024-079877 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] In Patent Document 1, the drive circuit (2) for generating a spark discharge from the spark plug (1) includes two coil pairs (11, 12). The first coil pair (11) is constructed by winding a primary coil (11a) and a secondary coil (11b) around an iron core (10). The second coil pair (12) is constructed by winding a primary coil (12a) and a secondary coil (12b) around an iron core (10) (paragraph 0017). Figures 1-2 Furthermore, the iron core (10) is constructed by making the components on which multiple thin iron plates are stacked in contact without gaps. In addition, the magnetic flux (Φ1) generated by energizing the primary coil (11a) of the first coil pair (11) and the magnetic flux (Φ2) generated by energizing the primary coil (12a) of the second coil pair (12) both pass through the common part (11c) in the iron core (10) (paragraph 0018).

[0009] In Patent Document 2, the ignition coil (104) connected to the spark plug (101) has a first coil group (40), a second coil group (50), and an iron core (60) (paragraph 0025). The iron core (60) has a structure composed of a first iron core (61), a second iron core (62), a one-end connecting iron core (63), and a other-end connecting iron core (64). The first iron core (61) passes through the inside of the first primary coil (L11) and the inside of the first secondary coil (L12) of the first coil group (40). The second iron core (62) passes through the inside of the second primary coil (L21) and the inside of the second secondary coil (L22) of the second coil group (50) (paragraph 0031). In addition, the one-end connecting iron core (63) connects one end (611) of the first iron core (61) and one end (621) of the second iron core (62). In addition, the other end connecting core (64) connects the other end (612) of the first core (61) and the other end (622) of the second core (62) (paragraph 0032). Thus, a closed loop magnetic circuit is formed by sequentially connecting the first core (61), the one-end connecting core (63), the second core (62), and the other-end connecting core (64).

[0010] Here, as described in paragraph 0025 of Patent Document 2, the two coil assemblies connected to the spark plug and the iron core, along with other components, are integrally housed within a housing (not shown). Furthermore, the gaps within the housing are filled with a thermosetting molding resin for insulating and securing the components. The molding resin is, for example, epoxy resin. The thermal conductivity of the epoxy resin is, for example, a relatively small value of about 0.1 to 0.8 W / mK. On the other hand, the thermal conductivity of the electromagnet steel plate (35A300) constituting the iron core is about 20 W / mK.

[0011] Furthermore, during the operation of the ignition coil, current flows through each primary coil when the primary coils of each coil group, which are surrounded by molding resin within the housing, are charged. Therefore, if the primary coils are repeatedly charged, the heat generated from them remains within the housing, potentially causing melting or malfunctions in surrounding components. Thus, there is room for improvement in the structure of the ignition coil to efficiently dissipate heat from the primary coils to the outside of the housing.

[0012] The purpose of this invention is to provide a technology that, by improving the structure of the ignition coil, which houses two coil groups connected to the spark plug within a housing, enables efficient heat dissipation from the primary coils to the outside of the housing.

[0013] Technical means for solving technical problems

[0014] To address the aforementioned issues, the first invention of this application is an ignition coil for an internal combustion engine, comprising a first primary coil, a second primary coil, a first through-core, a second primary coil, a second secondary coil, a second through-core, an outer peripheral core at one end, an outer peripheral core at the other end, and a housing. The first primary coil is composed of a first primary winding, with a DC voltage applied to one end and the other end connected to a ground point. The first secondary coil is composed of a first primary winding. The first through-core penetrates the inner sides of both the first primary coil and the first secondary coil, electromagnetically coupling the two coils. The second primary coil is composed of a second primary winding, with the DC voltage applied to one end and the other end connected to a ground point. The second secondary coil is composed of a second secondary winding. The second through-core penetrates the inner sides of both the second primary coil and the second secondary coil, electromagnetically coupling the two coils. The outer peripheral core at one end connects one end of the first through-core and one end of the second through-core. The other end outer peripheral core connects to the other end of the first through core and the other end of the second through core. The housing has a concave shape with an opening at the upper end formed by an upward opening, housing the first primary coil, the first secondary coil, the first through core, the second primary coil, the second secondary coil, the second through core, the one-end outer peripheral core, and the other-end outer peripheral core. Furthermore, the housing is filled with a thermosetting molding resin. Additionally, the upper ends of the one-end outer peripheral core and the other-end outer peripheral core are located above the first secondary coil and the second secondary coil, respectively.

[0015] The second invention of this application is an ignition coil of the first invention, wherein the upper end of the outer peripheral iron core on one end side and / or the upper end of the outer peripheral iron core on the other end side protrudes upward beyond the upper surface of the molding resin.

[0016] The third invention of this application is an ignition coil of the first or second invention, which further has a central iron core disposed between the first through iron core and the second through iron core, connecting the outer peripheral iron core on one end side and the outer peripheral iron core on the other end side.

[0017] The fourth invention of this application is an ignition coil of the third invention, wherein the central iron core and at least a portion of the outer peripheral iron core at one end and / or at least a portion of the outer peripheral iron core at the other end are formed by a single component.

[0018] The fifth invention of this application is an ignition coil of the third invention, wherein the central iron core and at least a portion of the outer peripheral iron core at one end and / or at least a portion of the outer peripheral iron core at the other end are formed of different components.

[0019] The sixth invention of this application is an ignition device comprising an ignition coil, a power supply, a first switching element, a second switching element, a first control unit, a second control unit, and a spark plug, as described in any one of the first to fifth inventions. The power supply applies the DC voltage to one end of the first primary coil and one end of the second primary coil, respectively. The first switching element is inserted between the other end of the first primary coil and a ground point, enabling switching the energization or de-energization of a first primary current flowing from the power supply to the first primary coil. The second switching element is inserted between the other end of the second primary coil and a ground point, enabling switching the energization or de-energization of a second primary current flowing from the power supply to the second primary coil. The first control unit controls the switching of the first switching element. The second control unit controls the switching of the second switching element. The spark plug ignites fuel by discharging in a gap based on the high voltage induced at one end of the first primary coil and / or the high voltage induced at one end of the second primary coil.

[0020] The seventh invention of this application is an ignition device of the sixth invention, which further has a high-voltage terminal held in the housing below the ignition coil, between the wire connecting one end of the primary coil and one end of the secondary coil to the spark plug.

[0021] Invention Effects

[0022] According to the first to seventh inventions of this application, by respectively arranging the upper ends of one-sided outer peripheral iron core and the upper ends of the other-sided outer peripheral iron core in the upper part of the housing near the opening, the influence of the thermal resistance of the molding resin can be suppressed, and the heat generated from each coil can be transferred upward. Thus, the heat generated from each coil can be dissipated upward from the housing via one-sided outer peripheral iron core and / or the other-sided outer peripheral iron core.

[0023] In particular, according to the second invention of this application, heat can be dissipated more efficiently to the top of the housing via one end outer peripheral iron core and / or the other end outer peripheral iron core.

[0024] In particular, according to the fourth invention of this application, the number of components in the ignition coil, including the iron core, can be reduced.

[0025] In particular, according to the fifth invention of this application, the central core, one-end outer peripheral core and / or the other-end outer peripheral core can be formed with good yield of steel plate material. Attached Figure Description

[0026] Figure 1 This is a block diagram schematically illustrating the operating environment of the ignition device for an internal combustion engine according to the first embodiment.

[0027] Figure 2This is a perspective view of the ignition device according to the first embodiment.

[0028] Figure 3 This is a perspective view of the ignition device according to the first embodiment.

[0029] Figure 4 This is a perspective view of the ignition device according to the first embodiment.

[0030] Figure 5 This is a perspective view of the ignition coil according to the first embodiment.

[0031] Figure 6 This is a schematic longitudinal sectional view of the ignition coil of the first embodiment as viewed from below.

[0032] Figure 7 This is a perspective view of the ignition device in the first modified example.

[0033] Figure 8 This is a three-dimensional view of the ignition coil in the second variation.

[0034] Figure 9 This is a perspective view of the ignition coil according to the second embodiment.

[0035] Figure 10 This is a three-dimensional view of the ignition coil in the third variation.

[0036] Figure 11 This is a perspective view of the third modified example with the resin cover of the ignition coil removed.

[0037] Figure 12 This is a perspective view of the fourth modified example with the resin cover of the ignition coil removed. Detailed Implementation

[0038] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the constituent elements described in these embodiments are merely illustrative and are not intended to limit the scope of the invention to these. Additionally, in the accompanying drawings, the dimensions and quantities of various parts are sometimes exaggerated or simplified as needed for ease of understanding. Furthermore, in the following description... Figure 5 and Figures 8-12 In some diagrams, silicon steel sheets stacked within laminated steel sheets are sometimes depicted in a simplified manner.

[0039] <1. First Implementation Method>

[0040] <1-1. Composition of the ignition device>

[0041] First, the configuration of the ignition device 1 for an internal combustion engine, which is the first embodiment of the present invention, will be described with reference to the accompanying drawings. Figure 1This is a block diagram schematically illustrating the operating environment of the ignition device 1 according to the first embodiment. Furthermore, as will be explained later, the first primary coil L11 and the first secondary coil L12 of the ignition coil 104 included in the ignition device 1 are arranged in a direction that overlaps with each other, but... Figure 1 In the diagram, for ease of understanding, they are shown side by side. Similarly, the second primary coil L21 and the second secondary coil L22 of the ignition coil 104 are arranged in a direction that overlaps with each other, but... Figure 1 In the diagram, for ease of understanding, they are shown side by side.

[0042] The ignition device 1 in this embodiment is, for example, an internal combustion engine such as an SI (spark ignition) reciprocating engine mounted in a vehicle body 100, and a device that applies a high voltage to the spark plug 101 to generate a spark discharge. The ignition device 1 is provided in each of one or more cylinders of the internal combustion engine.

[0043] In addition, such as Figure 1 As shown, in addition to the ignition device 1, the internal combustion engine also includes the spark plug 101, and the vehicle body 100 includes the power supply device 102 (battery) and the ECU 103 (Engine Control Unit). Furthermore, in a broader sense, the spark plug 101, the power supply device 102, and the ECU 103 can also be considered as being included in the ignition device 1.

[0044] Spark plug 101 is a device for ignition in the combustion chamber of an internal combustion engine. Spark plug 101 is electrically connected via a wire (hereinafter referred to as "first stage side ground wire Cg12") to one end Eg12 of the first stage coil L12 of the ignition coil 104 (described later). Spark plug 101 is inserted between one end Eg12 of the first stage coil L12 and the grounding point (ground) 151. Additionally, spark plug 101 is electrically connected via a wire (hereinafter referred to as "second stage side ground wire Cg22") to one end Eg22 of the second stage coil L22 of the ignition coil 104 (described later). Spark plug 101 is inserted between one end Eg22 of the second stage coil L22 and the grounding point 151. That is, in the ignition device 1, a common spark plug 101 is provided for both the first coil group 40 and the second coil group 50 (described later).

[0045] A high voltage is induced in the primary coil L12 and / or the secondary coil L22 of the ignition coil 104. If the sum of the high voltage induced at one end Eg12 of the primary coil L12 and the high voltage induced at one end Eg22 of the secondary coil L22 exceeds the gap d between the center electrode 161 and the ground electrode 162 of the spark plug 101 (refer to...) Figure 1If the insulation breakdown voltage in the spark plug is reduced, a discharge occurs in the gap d, generating a spark. This ignites the fuel filling the internal combustion engine. That is, the spark plug 101 ignites the fuel by discharging in the gap d based on the high voltage induced at one end Eg12 of the primary coil L12 and / or the high voltage induced at one end Eg22 of the secondary coil L22.

[0046] Furthermore, the primary side ground wire Cg12 and the secondary side ground wire Cg22 converge midway towards the spark plug 101, becoming the "secondary side ground wire Cg20". The spark plug 101 is inserted into the secondary side ground wire Cg20. Moreover, a high-voltage terminal HG is provided on the near-front side of the spark plug 101 (opposite to the grounding point 151). That is, the high-voltage terminal HG is located within the secondary side ground wire Cg20, which connects one end Eg12 of the primary coil L12 and one end Eg22 of the secondary coil L22 to the spark plug 101. The high-voltage output of the primary coil L12 and the high-voltage output of the secondary coil L22 are transmitted to the spark plug 101 via the high-voltage terminal HG.

[0047] The power supply device 102 is a rechargeable battery capable of charging and discharging DC power. In this embodiment, the power supply device 102 is electrically connected to the first primary coil L11, the first primary coil L12, the second primary coil L21, and the second secondary coil L22 of the ignition coil 104 (described later) via wires (hereinafter referred to as "power line 150"). The power supply device 102 applies DC voltage to one end Ep11 of the first primary coil L11, the other end Ep12 of the first primary coil L12, one end Ep21 of the second primary coil L21, and the other end Ep22 of the second secondary coil L22 of the ignition coil 104 via the power line 150. However, as explained later, by providing the first diode 131 and the second diode 132, the flow of current from the power supply device 102 side to the first primary coil L12 and the second secondary coil L22 is impeded.

[0048] ECU103 is an existing computer that comprehensively controls the operation of the transmission, engine, etc. of the vehicle body 100.

[0049] Figure 2 This is a perspective view of the ignition device 1 of this embodiment. Figure 3 From and Figure 2 A perspective view of the ignition device 1 of this embodiment viewed from different directions. Figure 4 It is Figure 3 The resin section 108 in the ignition device 1, described later, is shown in a perspective view in a non-displayed state. In this view... Figure 4 In the diagram, the resin surface 109, which serves as the upper surface of the resin portion 108, is shown in dashed lines. Furthermore, in... Figure 2 ~The following Figure 5 And the following Figures 7-10 For ease of explanation, “vertical direction”, “above the vertical direction” and “below the vertical direction” are defined, but the direction in which the ignition device 1 is configured is not limited to these during the manufacture and use of the ignition device 1.

[0050] like Figures 1-4 As shown, the ignition device 1 includes an ignition coil 104, a first igniter 105, a second igniter 106, a housing 107, a resin portion 108, a first diode 131, and a second diode 132. Furthermore, in a broader sense, the housing 107 and the resin portion 108 can also be considered as being included within the ignition coil 104.

[0051] Figure 5 This is a perspective view of the ignition coil 104 in this embodiment. Figure 6 This is a schematic longitudinal sectional view of the ignition coil 104 of this embodiment, viewed from below. Furthermore, in... Figure 6 In the diagram, the power supply unit 102 and other components connected to the ignition coil 104 are shown using double-dotted lines. For example... Figure 1 and Figures 4-6 As shown, the ignition coil 104 has a first coil group 40, a second coil group 50, and an iron core 60. The first coil group 40 and the second coil group 50 are arranged in a horizontal direction. Furthermore, as explained later, the first coil group 40 and the second coil group 50 are connected in parallel with respect to a spark plug 101. The first coil group 40 has a first coil 41, a first primary coil L11, and a first secondary coil L12. The second coil group 50 has a second coil 51, a second primary coil L21, and a second secondary coil L22. As explained in detail later, the ignition coil 104, together with the first igniter 105 and the second igniter 106, is integrally built into the housing 107.

[0052] Furthermore, in the following description of the ignition coil 104, the direction parallel to the first central axis Bc1 of the first coil 41 is referred to as the "first axial direction," the direction orthogonal to the first central axis Bc1 is referred to as the "first radial direction," and the direction along an arc centered on the first central axis Bc1 is referred to as the "first circumferential direction." Similarly, the direction parallel to the second central axis Bc2 of the second coil 51 is referred to as the "second axial direction," the direction orthogonal to the second central axis Bc2 is referred to as the "second radial direction," and the direction along an arc centered on the second central axis Bc2 is referred to as the "second circumferential direction." Additionally, "parallel direction" includes substantially parallel directions, and "orthogonal direction" also includes substantially orthogonal directions. Furthermore, in this embodiment, the first central axis Bc1 and the second central axis Bc2 are substantially parallel and substantially horizontal, respectively.

[0053] The first spool 41 includes a first primary spool 411 and a first secondary spool 412 that are interconnected. The first primary spool 411 and the first secondary spool 412 extend in a cylindrical shape along a first central axis Bc1. Furthermore, the first secondary spool 412 is disposed on the outer side of the first primary spool 411 in a first radial direction. The first primary spool 411 and the first secondary spool 412 are made of, for example, resin. The first primary coil L11 is formed by winding a conductor (hereinafter referred to as "first primary winding 811") along a first circumferential direction centered on the first central axis Bc1 on the outer circumferential surface of the first primary spool 411. That is, the first primary coil L11 is constituted by the first primary winding 811.

[0054] After the first primary coil L11 is formed, a first secondary coil 412 is arranged to cover the outer peripheral surface of the first primary coil L11 and connected to the first primary coil 411. Then, a first secondary coil L12 is formed by winding a wire different from the first primary winding 811 (hereinafter referred to as "first secondary winding 812") along a first circumferential direction centered on the first central axis Bc1 on the outer peripheral surface of the first secondary coil 412. That is, the first secondary coil L12 is composed of the first secondary winding 812. In this way, by arranging the first primary coil L11 and the first secondary coil L12 in a stacked manner, the ignition coil 104 containing them can be further miniaturized. However, the first primary coil L11 and the first secondary coil L12 are not only stacked and wound together in this way, for example, they can also be arranged adjacent to each other in the first axial direction.

[0055] The second spool 51 includes a second primary spool 511 and a second secondary spool 512 that are interconnected. The second primary spool 511 and the second secondary spool 512 extend in a cylindrical shape along the second central axis Bc2. The second secondary spool 512 is disposed on the outer side of the second primary spool 511 in a second radial direction. The materials used for the second primary spool 511 and the second secondary spool 512 are, for example, resin. The second primary coil L21 is formed by winding a conductor (hereinafter referred to as "second primary winding 821") along a second circumferential direction centered on the second central axis Bc2 on the outer circumferential surface of the second primary spool 511. That is, the second primary coil L21 is constituted by the second primary winding 821.

[0056] After the second primary coil L21 is formed, a second-stage coil 512 is arranged to cover the outer peripheral surface of the second primary coil L21 and connected to the second primary coil 511. Then, the second-stage coil L22 is formed by winding a wire different from the second primary winding 821 (hereinafter referred to as "second-stage winding 822") along the second circumferential direction centered on the second central axis Bc2 on the outer peripheral surface of the second-stage coil 512. That is, the second-stage coil L22 is composed of the second-stage winding 822. In this way, by arranging the second primary coil L21 and the second-stage coil L22 in a way that they are stacked on top of each other, the ignition coil 104 containing them can be further miniaturized. However, the second primary coil L21 and the second-stage coil L22 are not only stacked on top of each other and wound in this way, for example, they can also be arranged adjacent to each other in the second axial direction.

[0057] The core 60 of this embodiment has a structure composed of a first through core 61, a second through core 62, a one-end outer peripheral core 63, and a other-end outer peripheral core 64. The first through core 61, the second through core 62, the one-end outer peripheral core 63, and the other-end outer peripheral core 64 are, for example, formed of laminated steel plates made of silicon steel sheets. Furthermore, generally speaking, silicon steel sheets are electromagnetic steel sheets formed by mixing approximately a few percent of silicon into iron and then heat-treating the steel before rolling. However, the first through core 61, the second through core 62, the one-end outer peripheral core 63, and the other-end outer peripheral core 64 may also be made of steel plates other than silicon steel sheets. Additionally, the first through core 61, the second through core 62, the one-end outer peripheral core 63, and the other-end outer peripheral core 64 may also be made of powdered iron cores formed from sintered materials.

[0058] The first through core 61 extends substantially horizontally and cylindrically along the first central axis Bc1. Furthermore, the first through core 61 is inserted into the space 410 on the inner side of the first primary coil 411 in the first radial direction. That is, the first through core 61 passes through the inner side of the first primary coil L11 and the inner side of the first primary coil L12. The second through core 62 extends substantially horizontally and cylindrically along the second central axis Bc2. Furthermore, the second through core 62 is inserted into the space 510 on the inner side of the second primary coil 511 in the second radial direction. That is, the second through core 62 passes through the inner side of the second primary coil L21 and the inner side of the second primary coil L22.

[0059] In this embodiment, the outer peripheral core 63 on one end and the outer peripheral core 64 on the other end extend approximately horizontally and in a columnar shape in directions substantially orthogonal to the first central axis Bc1 and the second central axis Bc2, respectively. More specifically, as... Figure 5 and Figure 6As shown, a one-end outer peripheral core 63 is positioned above one end 611 of the first through core 61 and one end 621 of the second through core 62. Thus, the one-end outer peripheral core 63 connects one end 611 of the first through core 61 and one end 621 of the second through core 62. Furthermore, a other-end outer peripheral core 64 is positioned above the other end 612 of the first through core 61 and the other end 622 of the second through core 62. Thus, the other-end outer peripheral core 64 connects the other end 612 of the first through core 61 and the other end 622 of the second through core 62.

[0060] This forms a closed, annular magnetic circuit consisting of a first through-core 61, an outer peripheral core 63 at one end, a second through-core 62, and an outer peripheral core 64 at the other end, connected in sequence. Furthermore, the first through-core 61 electromagnetically couples the first primary coil L11 with the first secondary coil L12. Similarly, the second through-core 62 electromagnetically couples the second primary coil L21 with the second secondary coil L22.

[0061] Furthermore, in the first through core 61, the second through core 62, the outer peripheral core 63 at one end, and the outer peripheral core 64 at the other end, silicon steel plates are preferably stacked in directions perpendicular to the direction of magnetic flux travel in the closed magnetic circuit. However, in the first through core 61, the second through core 62, the outer peripheral core 63 at one end, and the outer peripheral core 64 at the other end, silicon steel plates may also be stacked in directions different from those perpendicular to the direction of magnetic flux travel in the closed magnetic circuit.

[0062] Furthermore, regarding the spatial arrangement of the ignition coil 104 within the housing 107, the first through-core 61 and the second through-core 62 extend in a generally horizontal columnar direction when the ignition coil 104 is housed within the housing 107. Therefore, the first through-core 61, when housed within the housing 107, is located further away from the upper end of the first primary coil L11 than the opening 120 of the housing 107 (described later). Similarly, the second through-core 62, when housed within the housing 107, is located further away from the opening 120 of the housing 107 than the upper end of the first primary coil L12. Moreover, the first through-core 61 and the second through-core 62 are also separately arranged from the side of the housing 107. On the other hand, the upper ends of the one-end outer peripheral core 63 and the other-end outer peripheral core 64 are located above the first primary coil L12 and the second primary coil L22, respectively. The effects of this structure will be described in detail later.

[0063] As described above, a power line 150, which serves as a conductor extending from the power supply device 102, is connected to one end Ep11 of the first primary coil L11. The other end Eg11 of the first primary coil L11 is connected to a grounding point (ground) 152 via a first igniter 105 (described later). By being controlled by the first igniter 105, a low DC voltage from the power supply device 102 is applied to one end Ep11 of the first primary coil L11, and a gradually increasing first primary current begins to flow in the first primary coil L11. Furthermore, in this embodiment, when a DC voltage from the power supply device 102 is applied to the first primary coil L11, an electromagnetic flux is generated in the first through-core 61 from the other end 612 toward one end 611.

[0064] The wire diameter of the first primary winding 812 is smaller than that of the first primary winding 811. Furthermore, the number of turns in the first primary winding 812 in the first primary coil L12 is greater than the number of turns in the first primary winding 811 in the first primary coil L11 (for example, approximately 100 times or more). Therefore, when the ignition coil 104 cuts off the first primary current, it boosts the low-voltage DC power supplied from the power supply device 102 to, for example, several thousand V to tens of thousands of V. That is, a high voltage is induced in the first primary winding L12. Then, the first primary winding L12 supplies the induced high-voltage power to the spark plug 101 via the secondary-side ground wires Cg12 and Cg20. This generates an electric spark in the spark plug 101, igniting the fuel.

[0065] In addition, such as Figure 1 As shown, a first diode 131 is connected in series with the first primary coil L12 on the primary side ground wire Cg12. The first diode 131 is positively oriented from one end Eg12 of the first primary coil L12 to the other end Ep12. This prevents the induced current from flowing backwards to the spark plug 101. This induced current is caused by the voltage induced in the first primary coil L12 by the gradually increasing first primary current when the first primary coil L11 is energized. In addition, as described above, a power line 150, which is a wire extending from the power supply device 102, is connected to the other end Ep12 of the first primary coil L12.

[0066] Furthermore, as described above, a power line 150, which serves as a conductor extending from the power supply device 102, is connected to one end Ep21 of the second primary coil L21. The other end Eg21 of the second primary coil L21 is connected to the ground point 152 via the second igniter 106, which will be described later. By being controlled by the second igniter 106, a low DC voltage from the power supply device 102 is applied to one end Ep21 of the second primary coil L21, and a gradually increasing second primary current begins to flow in the second primary coil L21. In addition, in this embodiment, when a DC voltage from the power supply device 102 is applied to the second primary coil L21, an electromagnetic flux is generated in the second through-core 62 from the other end 622 toward one end 621.

[0067] The wire diameter of the secondary winding 822 is smaller than that of the secondary primary winding 821. Furthermore, the number of turns in the secondary winding 822 of the secondary coil L22 is greater than the number of turns in the secondary primary winding 821 of the secondary primary coil L21 (for example, approximately 100 times or more). Therefore, when the ignition coil 104 cuts off the secondary primary current, it boosts the low-voltage DC power supplied from the power supply device 102 to, for example, several thousand V to tens of thousands of V. That is, a high voltage is induced in the secondary coil L22. Then, the secondary coil L22 supplies the induced high-voltage power to the spark plug 101 via the secondary-side ground wires Cg22 and Cg20. This allows the electric spark generated in the spark plug 101 to be maintained for a longer period.

[0068] In addition, such as Figure 1 As shown, a second diode 132 is connected in series with the second-stage coil L22 on the secondary-side ground wire Cg22. The second diode 132 is positively oriented from one end Eg22 of the second-stage coil L22 to the other end Ep22. This prevents the induced current from flowing backwards to the spark plug 101. This induced current is caused by the voltage induced in the second-stage coil L22 by the gradually increasing second primary current when the second primary coil L21 is energized. In addition, as described above, a power line 150, which is a wire extending from the power supply device 102, is connected to the other end Ep22 of the second-stage coil L22.

[0069] As described above, in this embodiment, in an ignition coil 104, a first through-core 61 inserted into the inner side of the first coil group 40 and a second through-core 62 inserted into the inner side of the second coil group 50 are connected to each other via an outer peripheral core 63 at one end and an outer peripheral core 64 at the other end, thereby forming a closed magnetic circuit. Therefore, compared to the case where a closed magnetic circuit is formed for each coil group 40, 50, the ignition coil 104, including the core 60, can be miniaturized overall. As a result, an ignition device 1 including the ignition coil 104 can be more easily installed in an internal combustion engine. Furthermore, since the number of components can be reduced, the overall manufacturing cost of the device is reduced.

[0070] The first igniter 105 is a semiconductor device connected to the first primary coil L11 and controlling the current flowing in the first primary coil L11. Additionally, the first igniter 105 is electrically connected to the ECU 103 and receives signals from the ECU 103 (hereinafter referred to as the "first EST signal S1"). The first igniter 105 has a first switching element 71 and a first driver IC 72. Furthermore, the first igniter 105 can also be integrated with the electronic circuitry of the ECU 103.

[0071] The first switching element 71 is, for example, an insulated gate bipolar transistor (IGBT). The first switching element 71 is inserted between the other end Eg11 of the first primary coil L11 and ground point 152. The collector (C) of the first switching element 71 is connected to the other end Eg11 of the first primary coil L11. The emitter (E) of the first switching element 71 is connected to ground point 152. The gate (G) of the first switching element 71 is connected to the first driver IC 72.

[0072] Thus, the first switching element 71 can switch the flow of the first primary current from the power supply device 102 to the first primary coil L11, either on or off. If the first switching element 71 is closed, the first primary current flows from the power supply device 102 to the first primary coil L11. If the first switching element 71 is open, the first primary current flowing in the first primary coil L11 is cut off. However, other types of transistors can also be used for the first switching element 71.

[0073] The first driver IC 72 controls the switching of the first switching element 71 based on the first EST signal S1 received from the ECU 103. The first driver IC 72 is equivalent to the "first control unit" of the present invention. The first driver IC 72 has a logic device connected to the first switching element 71. The logic device includes, for example, logic circuits, processors, CPLDs (complex programmable logic devices), FPGAs (field-programmable gate arrays), or ASICs (application-specific integrated circuits). The logic device performs calculations to activate the ignition device 1 to ignite the spark plug 101.

[0074] The second igniter 106 is a semiconductor device connected to the second primary coil L21 and controlling the current flowing in the second primary coil L21. Additionally, the second igniter 106 is electrically connected to the ECU 103 and receives a signal from the ECU 103 (hereinafter referred to as the "second EST signal S2"). The second igniter 106 has a second switching element 73 and a second drive IC 74. Furthermore, the second igniter 106 can also be integrated with the electronic circuitry of the ECU 103.

[0075] The second switching element 73 is, for example, an insulated gate bipolar transistor (IGBT). The second switching element 73 is inserted between the other end Eg21 of the second primary coil L21 and ground point 152. The collector (C) of the second switching element 73 is connected to the other end Eg21 of the second primary coil L21. The emitter (E) of the second switching element 73 is connected to ground point 152. The gate (G) of the second switching element 73 is connected to the second driver IC 74.

[0076] Thus, the second switching element 73 can switch the flow of the second primary current from the power supply device 102 to the second primary coil L21, either energizing or de-energizing it. If the second switching element 73 is closed, the second primary current flows from the power supply device 102 to the second primary coil L21. If the second switching element 73 is open, the flow of the second primary current in the second primary coil L21 is cut off. However, other types of transistors can also be used for the second switching element 73.

[0077] The second drive IC 74 controls the switching of the second switching element 73 based on the second EST signal S2 received from the ECU 103. The second drive IC 74 is equivalent to the "second control unit" of the present invention. The second drive IC 74 has a logic device connected to the second switching element 73. The logic device includes, for example, logic circuits, processors, CPLDs (complex programmable logic devices), FPGAs (field-programmable gate arrays), or ASICs (application-specific integrated circuits). The logic device performs computational processing to activate the ignition device 1 and maintain the electric spark generated in the spark plug 101 for a longer period of time.

[0078] The housing 107 is a container made of insulating resin. The housing 107 is shaped like the ignition device 1, having a generally concave shape that opens vertically upwards. Thus, an opening 120 is formed at the upper end of the housing 107. The housing 107 houses the components including the ignition coil 104, the first igniter 105, and the second igniter 106; specifically, the housing 107 houses the first primary coil L11, the first secondary coil L12, the first through-core 61, the second primary coil L21, the second secondary coil L22, the second through-core 62, the outer peripheral core 63 at one end, the outer peripheral core 64 at the other end, the first igniter 105, and the second igniter 106. Furthermore, the housing 107 has a main housing portion 91, a first connector portion 921, a second connector portion 922, fixing portions 931 and 932, and a lower housing portion 94.

[0079] The main receiving portion 91 has a concave shape that opens vertically upwards. The opening 120 is formed at the upper end of the main receiving portion 91. Hereinafter, the space inside the main receiving portion 91 will be referred to as the "internal space 910". The internal space 910 houses the ignition coil 104, the first igniter 105, and the second igniter 106. The ignition coil 104 is housed in the internal space 910 with the first axis of the first coil group 40 and the second axis of the second coil group 50 both oriented horizontally. The first igniter 105 is disposed on one side of the first axis of the first coil group 40. The second igniter 106 is disposed on one side of the second axis of the second coil group 50. Wires and the like, which connect to each part, are appropriately arranged around the ignition coil 104, the first igniter 105, and the second igniter 106.

[0080] During the manufacturing process of the ignition device 1, with the ignition coil 104, the first igniter 105, the second igniter 106, and the wires connected to them arranged in the internal space 910, a thermosetting molding resin for insulating and fixing these components is introduced. That is, the housing 107 is filled with thermosetting molding resin. For example, epoxy resin is used as the molding resin. Furthermore, the molding resin is filled to the vicinity of the opening 120 within the housing 107. Thus, after the molding resin cures, a resin portion 108 is formed, filling the gaps within the housing 107. As a result, within the internal space 910, the components including the ignition coil 104, the first igniter 105, and the second igniter 106 are held in their proper positions.

[0081] Furthermore, in this embodiment, the upper ends of one-sided outer peripheral core 63 and the upper ends of the other-sided outer peripheral core 64 are respectively arranged at the corners of the silicon steel plates (laminated steel plates) constituting one-sided outer peripheral core 63 and the other-sided outer peripheral core 64. Therefore, these corners may become sources of cracking in the molding resin. Therefore, as... Figure 5 As shown, a resin cover 66 is fitted in contact with the upper surface of one end of the outer peripheral core 63 and the upper surface of the other end of the outer peripheral core 64, respectively. Thus, by protecting the corners of the silicon steel plate (laminated steel plate) located at the upper ends of the one end of the outer peripheral core 63 and the other end of the outer peripheral core 64 by the resin cover 66, the generation of cracks in the molding resin can be suppressed.

[0082] Details will be described later, but during the operation of the ignition coil 104, current repeatedly flows through the primary coils L11 and L21 of each coil group 40, 50, which are surrounded by the resin portion 108 within the housing 107. Therefore, heat is repeatedly generated primarily from each primary coil L11, L21. Furthermore, if this heat remains within the housing 107, it could potentially affect surrounding components. Therefore, it is necessary to remove the generated heat and dissipate it to the outside of the housing 107. However, the epoxy resin forming the resin portion 108 surrounding each coil group 40, 50 has a relatively low thermal conductivity of approximately 0.1 to 0.8 W / mK. Therefore, it is difficult to dissipate the heat generated from each primary coil L11, L21, etc., to the outside of the housing 107 via the resin portion 108.

[0083] Furthermore, the electromagnetic steel plates (35A300) forming the first through-core 61 penetrating the inner side of the first primary coil L11 and the second through-core 62 penetrating the inner side of the second primary coil L21 have a relatively high thermal conductivity of about 20 W / mK, but they are positioned separately from the opening 120 of the housing 107 downwards. Additionally, as described above, the first through-core 61 and the second through-core 62 are also separately positioned from the side of the housing 107.

[0084] Therefore, in this invention, the upper ends of the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64, which connect the first through core 61 and the second through core 62, are located above the first primary coil L12 and the second primary coil L22, respectively. That is, the upper ends of the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64 are respectively positioned near the resin surface 109, which is the upper surface of the resin portion 108, further upwards. In other words, the upper ends of the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64 are respectively positioned above the opening 120 of the housing 107.

[0085] This suppresses the effects of thermal resistance on the molding resin constituting the resin section 108, and allows heat generated from the primary coils L11, L21, etc. of each coil group 40, 50 to be further transferred upwards. As a result, heat generated from the primary coils L11, L21, etc. of each coil group 40, 50 can be dissipated upwards from the housing 107 via the outer peripheral iron core 63 at one end and the outer peripheral iron core 64 at the other end.

[0086] In addition, such as Figure 7 As shown in the first variation, the upper end of one-sided outer peripheral core 63 and the upper end of the other-sided outer peripheral core 64, or either of them, may be exposed upwards beyond the resin surface 109. That is, the upper end of one-sided outer peripheral core 63 and / or the upper end of the other-sided outer peripheral core 64 may be exposed upwards beyond the upper surface of the molding resin constituting the resin portion 108. As a result, heat generated from the primary coils L11, L21, etc. of each coil group 40, 50 can be dissipated more efficiently to the upper part of the housing 107 via the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64.

[0087] In addition, such as Figure 8 As shown in the second variation, the outer peripheral core 63 at one end can also be configured to be adjacent to one end face of the first through core 61 along its first axial direction and to one end face of the second through core 62 along its second axial direction. Alternatively, the outer peripheral core 64 at the other end can also be configured to be adjacent to the end face of the first through core 61 along its other axial direction and to the end face of the second through core 62 along its second axial direction. In this case, the outer peripheral core 63 at one end and the outer peripheral core 64 at the other end can also be connected to the first through core 61 and the second through core 62, respectively.

[0088] Then, in the second variation, similar to this embodiment, the upper ends of the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64 are positioned above the first-stage coil L12 and the second-stage coil L22, respectively. That is, the upper ends of the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64 are respectively positioned above the resin surface 109 and the opening 120 of the housing 107. As a result, the influence of the thermal resistance of the molding resin constituting the resin part 108 can be suppressed, and the heat generated from the primary coils L11, L21, etc. of each coil group 40, 50 can be transferred upwards via the one-sided outer peripheral core 63 and the other-sided outer peripheral core 64 and dissipated upwards from the housing 107.

[0089] like Figures 2-4 As shown, a first connector portion 921 and a second connector portion 922 are arranged side-by-side in the horizontal direction on the side of the main receiving portion 91 of the housing 107. The first connector portion 921 is located on the side closer to the first igniter 105 along the first axial direction. The wires connected to the first igniter 105 and the power line 150 extending from the first primary winding 811 are led out to the outside of the housing 107 via the first connector portion 921 and connected to the ECU 103, power supply unit 102, etc. The second connector portion 922 is located on the side closer to the second igniter 106 along the second axial direction. The wires connected to the second igniter 106 and the power line 150 extending from the second primary winding 821 are led out to the outside of the housing 107 via the second connector portion 922 and connected to the ECU 103, power supply unit 102, etc.

[0090] Furthermore, on the side of the main receiving portion 91 of the housing 107, fixing portions 931 and 932 are provided at positions different from those where the first connector portion 921 and the second connector portion 922 are provided. The fixing portions 931 and 932 are formed in positions opposite to each other. The fixing portions 931 and 932 are generally triangular prism-shaped protrusions from the main receiving portion 91 for mounting and fixing the ignition device 1 to the engine block.

[0091] Furthermore, the lower receiving portion 94 is a cylindrical component extending vertically. The upper end of the lower receiving portion 94 is fixed near the center of the bottom of the main receiving portion 91. Additionally, a high-voltage terminal HG is fixed within the space inside the lower receiving portion 94. That is, the high-voltage terminal HG is held in the housing 107 below the ignition coil 104. Furthermore, a hole 915 penetrating the bottom of the main receiving portion 91 is provided near the center of the bottom. The space inside the lower receiving portion 94 communicates with the internal space 910 of the main receiving portion 91 via the hole 915. The secondary-side grounding wire Cg20 is inserted into the inside of the lower receiving portion 94 via the hole 915 and connected to the high-voltage terminal HG.

[0092] <1-2. Operation of the ignition device>

[0093] The operation of ignition device 1 will be explained next.

[0094] When the ignition device 1 is activated, firstly at time t0, the signal level of the first EST signal S1 sent from ECU 103 to the first drive IC 72 is changed from L to H. Then, based on the first EST signal S1, the first drive IC 72 switches the first switching element 71 from an open-circuit state to a closed state. This applies a low DC voltage from the first power supply device 102 to one end Ep11 of the first primary coil L11. Then, the first primary current flows in the first primary winding 811 forming the first primary coil L11, generating a magnetomotive force in the first primary coil L11. Additionally, an electromagnetic flux is generated in the first through-core 61 from the other end 612 towards one end 611. With the electromagnetic communication The corresponding magnetic field acts on the iron core 60.

[0095] Next, at time t1, which is later than time t0, the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from H to L, and simultaneously the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from L to H. Thus, the first drive IC72 switches the first switching element 71 from a closed state to an open state, cutting off the primary current (first primary current) flowing from the power supply device 102 to the first primary coil L11. Consequently, in the first primary coil L12, which is electromagnetically coupled to the first primary coil L11 via the iron core 60, mutual inductance generates a current that is in sync with the aforementioned electromagnetic current. The direction is the opposite direction of cutting off the magnetic flux. This induces a large electromotive force. At this time, the voltage applied to one end of the primary coil L12, Eg12, reaches negative several thousand V to tens of thousands V relative to the ground point 152. As a result, the fuel is ignited by an electric spark generated in the spark plug 101 connected to one end of the primary coil L12, Eg12, and thus an induced current (primary current) flows in the primary coil L12.

[0096] Additionally, at time t1, the second drive IC 74 switches the second switching element 73 from an open-circuit state to a closed state. This applies a low DC voltage from the power supply device 102 to one end Ep21 of the second primary coil L21. Then, a second primary current flows in the second primary winding 821 forming the second primary coil L21, generating a magnetomotive force in the second primary coil L21. Furthermore, an electromagnetic flux is generated in the second through-core 62 from the other end 622 towards one end 621. With the electromagnetic communication A corresponding magnetic field acts on the iron core 60. Furthermore, this electromagnetic flux... The direction becomes the same as the above-mentioned cut-off magnetic flux In the same direction. Therefore, the magnetic flux generated in the closed magnetic circuit of the iron core 60 is amplified. As a result, the current supplied to the spark plug 101 and the ignition energy can be increased.

[0097] Then, at time t2, which is later than time t1, the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from H to L, and at the same time, the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from L to H. As a result, the second drive IC74 switches the second switching element 73 from a closed state to an open state, cutting off the primary current (second primary current) flowing from the power supply device 102 to the second primary coil L21. Consequently, in the second primary coil L22, which is electromagnetically coupled to the second primary coil L21 via the iron core 60, mutual inductance generates a current that is in sync with the aforementioned electromagnetic current. The direction is the opposite direction of cutting off the magnetic flux. This induces a large electromotive force. At this time, the voltage applied to one end of the secondary coil L22, Eg22, reaches negative several thousand V to tens of thousands V relative to the ground point 152. As a result, since the electric spark and flame generated around the spark plug 101 connected to one end of the secondary coil L22, Eg22, can be maintained, the induced current (secondary current) flows in the secondary coil L22.

[0098] Additionally, at time t2, the first drive IC 72 switches the first switching element 71 from an open-circuit state to a closed state. This applies a low DC voltage from the power supply device 102 to one end Ep11 of the first primary coil L11. Then, a first primary current flows in the first primary winding 811 forming the first primary coil L11, generating a magnetomotive force in the first primary coil L11. Furthermore, an electromagnetic flux is generated in the first through-core 61 from the other end 612 towards one end 611. With the electromagnetic communication A corresponding magnetic field acts on the iron core 60. Furthermore, this electromagnetic flux... The direction becomes the same as the above-mentioned cut-off magnetic flux In the same direction. Therefore, the magnetic flux generated in the closed magnetic circuit of the iron core 60 is amplified. As a result, the current supplied to the spark plug 101 and the ignition energy can be further increased.

[0099] As described above, the first drive IC 72 alternately energizes and de-energizes the first primary coil L11 multiple times. Conversely, the second drive IC 74 energizes the second primary coil L21 at the timing when the first drive IC 72 de-energizes the first primary coil L11, and then de-energizes the second primary coil L21 at the timing when the first drive IC 72 energizes the first primary coil L11. By performing this control, the flame generated around the spark plug 101 can be maintained for a longer period.

[0100] <2. Second Implementation Method>

[0101] Next, the second embodiment of the present invention will be described. Furthermore, the following description will focus on the differences from the first embodiment, omitting repeated descriptions of parts identical to those in the first embodiment. Additionally, components having the same structure as those in the first embodiment will be labeled and described using the same reference numerals as in the first embodiment.

[0102] Figure 9 This is a perspective view of the ignition coil 104 in this embodiment. Figure 9 As shown, the ignition coil 104 has a first coil group 40, a second coil group 50, and an iron core 60B.

[0103] The core 60B of this embodiment has a structure composed of a first through core 61, a second through core 62, a one-end outer peripheral core 63, a other-end outer peripheral core 64, and a central core 65B. The first through core 61, the second through core 62, the one-end outer peripheral core 63, the other-end outer peripheral core 64, and the central core 65B are, for example, formed of laminated steel plates made of silicon steel sheets. However, the first through core 61, the second through core 62, the one-end outer peripheral core 63, the other-end outer peripheral core 64, and the central core 65B may also be made of steel plates other than silicon steel sheets. Furthermore, the first through core 61, the second through core 62, the one-end outer peripheral core 63, the other-end outer peripheral core 64, and the central core 65B may also be made of powdered iron cores formed of sintered materials.

[0104] Similar to the first embodiment, a one-end outer peripheral core 63 is positioned above one end of the first through core 61 along its first axial direction and above one end of the second through core 62 along its second axial direction. Conversely, a other-end outer peripheral core 64 is positioned above the other end of the first through core 61 along its first axial direction and above the other end of the second through core 62 along its second axial direction. Thus, the one-end outer peripheral core 63 and the other-end outer peripheral core 64 are respectively connected to the first through core 61 and the second through core 62.

[0105] The central core 65B extends in a columnar shape, approximately parallel to and horizontal to the first and second axial directions. When viewed from above, the ignition coil 104 is positioned between the first through core 61 and the second through core 62. One end 651B of the central core 65B is connected to one end-side outer peripheral core 63. The other end 652B of the central core 65B is connected to the other end-side outer peripheral core 64. In other words, the central core 65B is positioned between the first through core 61 and the second through core 62, connecting one end-side outer peripheral core 63 and the other end-side outer peripheral core 64.

[0106] Thus, a closed loop magnetic circuit is formed by sequentially connecting the first through-core 61, a portion of the outer peripheral core 63 at one end, the central core 65B, and a portion of the outer peripheral core 64 at the other end. Additionally, a closed loop magnetic circuit is formed by sequentially connecting the second through-core 62, a portion of the outer peripheral core 63 at one end, the central core 65B, and a portion of the outer peripheral core 64 at the other end. Furthermore, in this embodiment, when a DC voltage from the power supply device 102 is applied to the first primary coil L11, electromagnetic flux is generated in the order of the first through-core 61, a portion of the outer peripheral core 63 at one end, the central core 65B, and a portion of the outer peripheral core 64 at the other end. Also in this embodiment, when a DC voltage from the power supply device 102 is applied to the second primary coil L21, electromagnetic flux is generated in the order of the second through-core 62, a portion of the outer peripheral core 64 at the other end, the central core 65B, and a portion of the outer peripheral core 63 at one end.

[0107] Furthermore, in this embodiment, the upper ends of the one-sided outer peripheral core 63, the other-sided outer peripheral core 64, and the central core 65B are located above the primary coil L12 and the secondary coil L22, respectively. That is, the upper ends of the one-sided outer peripheral core 63, the other-sided outer peripheral core 64, and the central core 65B are respectively positioned above the resin surface 109 and the opening 120 of the housing 107. As a result, the influence of the thermal resistance of the molding resin constituting the resin part 108 can be suppressed, and the heat generated from the primary coils L11, L21, etc. of each coil group 40, 50 can be transferred upwards and dissipated upwards from the upper ends of the one-sided outer peripheral core 63, the other-sided outer peripheral core 64, and the central core 65B.

[0108] Figure 10 This is a perspective view of the ignition coil 104 in the third variation. Additionally, Figure 11 From Figure 10A perspective view of the ignition coil 104 with its outer peripheral core 63 at one end, outer peripheral core 64 at the other end, and central core 65B removed from their resin covers 66. Figure 10 and Figure 11 As shown in the third variation, the outer peripheral core 63 at one end can also be configured to be adjacent to one end face of the first through core 61 along its first axial direction and to one end face of the second through core 62 along its second axial direction. Alternatively, the outer peripheral core 64 at the other end can also be configured to be adjacent to the other end face of the first through core 61 along its first axial direction and to the other end face of the second through core 62 along its second axial direction. In this case, the outer peripheral core 63 at one end and the outer peripheral core 64 at the other end can also be connected to the first through core 61 and the second through core 62, respectively.

[0109] Furthermore, in this modified example, the central iron core 65B, a portion of the outer peripheral iron core 63 at one end, and a portion of the outer peripheral iron core 64 at the other end are each formed from a single component. This allows for a reduction in the number of components in the ignition coil 104, including the iron core 60B. However, as... Figure 12 As shown in the fourth variation, the central core 65B, the outer peripheral core 63 at one end, and the outer peripheral core 64 at the other end can also be formed from different components. Furthermore, one of the central core 65B, a portion of the outer peripheral core 63 at one end, or a portion of the outer peripheral core 64 at the other end can also be formed from different components. Therefore, even with a core 60B having a complex shape, it can be manufactured by punching material with good yield when manufacturing the steel plate used to constitute the core 60B, making it easier to form the core 60B.

[0110] That is, such as Figure 11 As shown in the third variation, at least a portion of the central core 65B and at least a portion of the outer peripheral core 63 at one end and / or at least a portion of the outer peripheral core 64 at the other end can also be formed from a single component. This reduces the number of components in the ignition coil 104, including the core 60B. Furthermore, as... Figure 12 As shown in the fourth variation, at least a portion of the central core 65B and at least a portion of the outer peripheral core 63 at one end and / or the outer peripheral core 64 at the other end can also be formed from different components. Therefore, when manufacturing the steel plates used to form them, the central core 65B and the outer peripheral core 63 at one end and / or the outer peripheral core 64 can be manufactured by punching materials with good yield, and the core 60B can be formed more easily.

[0111] When the ignition device 1 is activated, the first drive IC 72 repeatedly and alternately energizes and de-energizes the first primary coil L11. When the energization of the first primary coil L11 is de-energized, an electromagnetic flux is generated in the following order: the first through-core 61, a portion of the outer peripheral core 64 at the other end, the central core 65B, and a portion of the outer peripheral core 63 at one end. At this time, the voltage applied to one end Eg12 of the first primary coil L12 reaches a negative value of several thousand V to tens of thousands V relative to the ground point 152. As a result, the fuel is ignited by an electric spark generated in the spark plug 101 connected to one end Eg12 of the first primary coil L12, and an induced current (first primary current) flows in the first primary coil L12.

[0112] Furthermore, the second drive IC74 repeatedly and alternately energizes and de-energizes the second primary coil L21. When the energization of the second primary coil L21 is de-energized, an electromagnetic flux is generated in the following order: the second through core 62, a portion of the outer peripheral core 64 at the other end, the central core 65B, and a portion of the outer peripheral core 63 at one end. At this time, the voltage applied to one end Eg22 of the secondary coil L22 reaches negative several thousand V to tens of thousands V relative to the ground point 152. As a result, since the electric spark and flame generated around the spark plug 101 connected to one end Eg22 of the secondary coil L22 can be maintained, an induced current (secondary current) flows in the secondary coil L22.

[0113] <3. Variations>

[0114] The above describes exemplary embodiments of the present invention, but the present invention is not limited to the above embodiments.

[0115] The ignition coil and ignition device of the present invention can be installed not only in automobiles and other vehicles, but also in various devices such as generators and industrial machinery, as long as they are used to generate an electric spark in the spark plug of an internal combustion engine to ignite the fuel.

[0116] The shape and structure of the detailed parts of the ignition coil and ignition device described above can also be appropriately modified without departing from the spirit of the present invention. Furthermore, the elements appearing in the above embodiments and modifications can be appropriately combined without creating contradictions.

[0117] Explanation of reference numerals in the attached figures

[0118] 1 Ignition device

[0119] 60, 60B iron core

[0120] 61 First Through Core

[0121] 62 Second Through Core

[0122] 63 One-end outer perimeter iron core

[0123] 64. The other end of the outer peripheral iron core

[0124] 65B center core

[0125] 71 First Switching Element

[0126] 72 First Driver IC (First Control Unit)

[0127] 73 Second Switching Element

[0128] 74 Second Driver IC (Second Control Unit)

[0129] 101 Spark Plug

[0130] 102 Power Supply Unit

[0131] 104 Ignition Coil

[0132] 105 First Ignition Device

[0133] 106 Second Ignition Device

[0134] 107 Housing

[0135] 108 Resin Section

[0136] 109 Resin Surface

[0137] 120 Opening

[0138] One end of 611 (the first iron core)

[0139] The other end of 612 (the first iron core)

[0140] 621 (one end of the second core)

[0141] The other end of 622 (the second core)

[0142] One end of 651B (center core)

[0143] The other end of 652B (center core)

[0144] 811 First Primary Winding

[0145] 812 Primary winding

[0146] 821 Second Primary Winding

[0147] 822 Secondary winding

[0148] 910 (the internal space of the shell)

[0149] Eg11 (the other end of the first primary coil)

[0150] Eg12 (one end of the primary coil)

[0151] The other end of Eg21 (the second primary coil)

[0152] One end of Eg22 (second stage coil)

[0153] One end of Ep11 (the first primary coil)

[0154] The other end of Ep12 (the first primary coil)

[0155] One end of Ep21 (the second primary coil)

[0156] The other end of Ep22 (the second stage coil)

[0157] HG High Voltage Terminal

[0158] L11 First primary coil

[0159] L12 First stage coil

[0160] L21 Second Primary Coil

[0161] L22 Secondary coil

Claims

1. An ignition coil for use in an internal combustion engine, having: The first primary coil, which is composed of a first primary winding, has a DC voltage applied to one end and the other end connected to a ground point; The primary coil is composed of primary windings; A first through-core passes through the inner side of the first primary coil and the inner side of the first primary coil, and electromagnetically couples the first primary coil with the first primary coil. The second primary coil, which is composed of a second primary winding, has the DC voltage applied to one end and the other end connected to the ground point; The second-stage coil is composed of a second-stage winding; The second through-core passes through the inner side of the second primary coil and the inner side of the second secondary coil, and electromagnetically couples the second primary coil with the second secondary coil. One end of the outer peripheral iron core connects one end of the first through iron core and one end of the second through iron core; The other end of the outer peripheral iron core connects the other end of the first through iron core and the other end of the second through iron core; and The housing has a concave shape with an opening at the upper end formed by an upward opening, and houses the first primary coil, the first secondary coil, the first through-core, the second primary coil, the second secondary coil, the second through-core, the outer peripheral core at one end, and the outer peripheral core at the other end. The housing is filled with thermosetting molding resin. The upper ends of the outer peripheral core on one end and the upper ends of the outer peripheral core on the other end are located above the first-stage coil and the second-stage coil, respectively.

2. The ignition coil as described in claim 1, The upper end of the outer peripheral iron core on one end side and / or the upper end of the outer peripheral iron core on the other end side protrudes upwards from the upper surface of the molding resin.

3. The ignition coil as described in claim 1, It also has a central iron core, which is disposed between the first through iron core and the second through iron core, connecting the outer peripheral iron core on one end side and the outer peripheral iron core on the other end side.

4. The ignition coil as described in claim 3, The central core and at least a portion of the outer peripheral core at one end and / or at least a portion of the outer peripheral core at the other end are each formed by a single component.

5. The ignition coil as described in claim 3, The central core and at least a portion of the outer peripheral core at one end and / or at least a portion of the outer peripheral core at the other end are formed by different components.

6. An ignition device, comprising: The ignition coil as described in any one of claims 1 to 5; A power supply device that applies the DC voltage to one end of the first primary coil and one end of the second primary coil, respectively; A first switching element, inserted between the other end of the first primary coil and a ground point, is capable of switching the energization or de-energization of the first primary current flowing from the power supply device to the first primary coil. The second switching element, which is inserted between the other end of the second primary coil and the ground point, is capable of switching the energization or de-energization of the second primary current flowing from the power supply device to the second primary coil. A first control unit controls the switching of the first switching element; The second control unit controls the switching of the second switching element; as well as A spark plug ignites fuel by discharging in a gap based on a high voltage induced at one end of the primary stage coil and / or a high voltage induced at one end of the secondary stage coil.

7. The ignition device as described in claim 6, It also has a high-voltage terminal, which is held in the housing below the ignition coil, between the wires connecting one end of the primary coil and one end of the secondary coil to the spark plug.

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