Ignition coil and ignition device

Abstract

Provided is a technique with which it is possible to further reduce the size and increase the energy of an ignition coil for an internal combustion engine capable of DCO ignition. A DC voltage is applied to one end of each of the first primary coil (L11) and the second primary coil (L21), and the other end is connected to a ground point (152). The first iron core (61) penetrates through the inner side of the first primary coil (L11) and the inner side of the first secondary coil (L12). The second iron core (62) passes through the inner side of the second primary coil (L21) and the inner side of the second secondary coil (L22). Furthermore, one ends (611, 621) of the iron cores (61, 62) are connected to each other, and the other ends (612, 622) are connected to each other, thereby forming a closed magnetic circuit. When a DC voltage is applied to the first primary coil (L11), magnetic flux is formed in the first core (61) from the other end (612) toward the one end (611). When a DC voltage is applied to the second primary coil (L21), magnetic flux is formed in the second core (62) from the other end (622) toward the one end (621).

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, as a countermeasure to resource depletion, lean combustion, where the proportion of fuel is lower than the stoichiometric air-fuel ratio, was sometimes used in internal combustion engines such as automobiles to improve fuel efficiency in order to improve fuel economy. Furthermore, as a countermeasure to global warming and to achieve a decarbonized society, the use of carbon-free ammonia as a fuel has been studied. However, these fuels are less flammable than regular 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 where the spark plug discharges repeatedly, and DCO (dual coil offset) ignition where the spark plug discharges continuously for a certain period near the ignition point. For example, Patent Document 1 discloses an ignition system for an internal combustion engine employing the DCO ignition method.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 6005943 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The ignition device for an internal combustion engine in Patent Document 1 consists of ignition coils Ca and Cb, igniters IGTa and IGTb, and a housing (10) that houses them (paragraph 0021). Figure 1 -2). Ignition coil Ca has a primary coil La1, a secondary coil La2, and an iron core Ma, and ignition coil Cb has the same structure (paragraph 0022). Furthermore, the secondary coils La2 and Lb2 of each ignition coil Ca and Cb are connected to a common spark plug PG. When an ignition signal is input, the ignition system boosts the bias voltage Vout of the DC-DC converter and applies the boosted voltage to the spark plug PG. Thus, a high voltage from both ignition coils Ca and Cb is applied to the spark plug PG (paragraphs 0025, 0027).

[0008] However, as in Patent Document 1, when the two ignition coils Ca and Cb each form a closed magnetic circuit with an iron core, there is a technical problem that the overall size of the device increases. Therefore, in order to miniaturize the device as a whole and make it easier to mount it on an internal combustion engine, there is room to improve the structure of each ignition coil or iron core.

[0009] The purpose of this invention is to provide a technology that improves the structure of an ignition coil for an internal combustion engine capable of DCO ignition, thereby enabling further miniaturization of the device as a whole.

[0010] Technical means for solving technical problems

[0011] To solve the aforementioned technical problems, 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 iron core, a second primary coil, a second secondary coil, and a second iron core. 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 second primary coil is composed of a first secondary winding. The first iron core penetrates the inner sides of both the first primary coil and the second primary 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 iron core penetrates the inner sides of both the second primary coil and the second secondary coil, electromagnetically coupling the two coils. Connecting one end of the first iron core to one end of the second iron core, and connecting the other ends of both the first and second iron cores, forms a closed magnetic circuit. When the DC voltage is applied to the first primary coil, a magnetic flux is generated in the first iron core from one end to the other. When the DC voltage is applied to the second primary coil, a magnetic flux is formed in the second iron core from one end to the other.

[0012] The second 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 the first invention. 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 it to switch 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 it to switch 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 the other end of the first primary coil and / or the high voltage induced at the other end of the second primary coil.

[0013] The third invention of this application is an ignition device of the second invention, wherein the first control unit performs primary energization control, discharge control, and push-up control. The primary energization control is achieved by setting the first switching element to a closed state, thereby allowing the first primary current to flow in the first primary coil and generate a magnetomotive force. The discharge control is achieved by switching the first switching element to an open state after the primary energization control, inducing a high voltage at the other end of the first primary coil, and discharging in the gap of the spark plug. Furthermore, the second control unit performs push-up control and discharge control. The push-up control performed by the second control unit is achieved by setting the second switching element to a closed state at the time the first control unit performs the discharge control, thereby allowing the second primary current to flow in the second primary coil and increasing the magnetic flux generated in the closed magnetic circuit. In addition, the second control unit performs the primary energization control by simultaneously performing the push-up control and the primary energization control to allow the second primary current to flow in the second primary coil and generate a magnetomotive force. Furthermore, the discharge control performed by the second control unit involves switching the second switching element to the open state after the second control unit performs the boost control, inducing a high voltage at the other end of the secondary coil, thereby continuously discharging it in the spark plug gap. Additionally, during the timing of the discharge control performed by the second control unit, the first control unit further performs the boost control by setting the first switching element back to the closed state, thereby increasing the magnetic flux generated in the closed magnetic circuit by allowing the first primary current to flow in the first primary coil.

[0014] The fourth invention of this application is an ignition device of the third invention, wherein after the first control unit performs the primary power-on control, it alternately repeats the discharge control and the boost control multiple times. Furthermore, whenever the first control unit performs the discharge control, the second control unit performs the boost control, and whenever the first control unit performs the boost control, the second control unit performs the discharge control.

[0015] Invention Effects

[0016] According to the first to fourth inventions of this application, by connecting the iron cores used in two coil groups to form a closed magnetic circuit, the ignition coil containing the iron core can be miniaturized as a whole.

[0017] Specifically, according to the third invention of this application, during the timing of discharging control of the first primary coil, a second primary current flows in the second primary coil, increasing the magnetic flux generated in the closed magnetic circuit, thereby maintaining the spark around the spark plug for a longer period of time. Furthermore, during the timing of discharging control of the second primary coil, the flow of a first primary current in the first primary coil increases the magnetic flux generated in the closed magnetic circuit, thereby maintaining the spark around the spark plug for a longer period of time.

[0018] In particular, according to the fourth invention of this application, the flame generated around the spark plug can be maintained for a longer period of time. Attached Figure Description

[0019] Figure 1 It is a block diagram schematically illustrating the working environment of an ignition device for an internal combustion engine.

[0020] Figure 2 This is a schematic longitudinal sectional view of the ignition coil.

[0021] Figure 3 This is a schematic longitudinal sectional view of the ignition coil.

[0022] Figure 4 It is a graph showing, in time sequence, the waveforms of the first EST signal, the first primary current, the first secondary current, the second EST signal, the second primary current, the second secondary current, and the waveforms of the first and second secondary currents when the ignition device is activated.

[0023] Figure 5 This is an illustrative diagram showing the orientation of the magnetic flux during primary energization control.

[0024] Figure 6 This is an illustrative diagram showing the orientation of the magnetic flux during discharge control.

[0025] Figure 7 This is an illustrative diagram showing the orientation of the magnetic flux during discharge control. Detailed Implementation

[0026] 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 present invention. Additionally, in the accompanying drawings, the dimensions or quantities of various parts may be exaggerated or simplified as needed for ease of understanding.

[0027] <1. First Implementation>

[0028] <1-1. Structure of the ignition device>

[0029] First, the structure of the ignition device 1 for an internal combustion engine according to the first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a block diagram schematically illustrating the operating environment of the ignition device 1 according to the first embodiment. Furthermore, as described 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 adjacent to each other. 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, the elements are arranged adjacently.

[0030] The ignition device 1 in this embodiment is, for example, an internal combustion engine such as an SI (spark ignition) reciprocating engine used in the body 100 of an automobile or the like, which applies a high voltage to the spark plug 101 to generate a spark discharge. The ignition device 1 is provided in one or more cylinders of the internal combustion engine.

[0031] In addition, such as Figure 1 As shown, the vehicle body 100, in addition to the ignition device 1, also includes the spark plug 101, 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 by the ignition device 1.

[0032] Spark plug 101 is a device used to achieve 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 the other end Eg12 of the first stage coil L12 of the ignition coil 104 (described later). Spark plug 101 is inserted between the other end Eg12 of the first stage coil L12 and the ground point (ground wire) 151. Furthermore, spark plug 101 is electrically connected via a wire (hereinafter referred to as "second stage side ground wire Cg22") to the other end Eg22 of the second stage coil L22 of the ignition coil 104 (described later). Spark plug 101 is inserted between the other end Eg22 of the second stage coil L22 and the ground point (ground wire) 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).

[0033] A high voltage is induced in the primary coil L12 and / or the secondary coil L22 of the ignition coil 104. The sum of the high voltage induced at the other end Eg12 of the primary coil L12 and the high voltage induced at the other 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 1 When the insulation breakdown voltage in the spark plug L11 is reached, a discharge occurs in the gap d, generating a spark. This ignites the fuel in the internal combustion engine. Specifically, the spark plug 101 discharges in the gap d based on the high voltage induced at the other end of the primary coil L12 (Eg12) and / or the high voltage induced at the other end of the secondary coil L22 (Eg22), thereby igniting the fuel.

[0034] Furthermore, in this embodiment, the fuel used is a lean fuel with a proportion lower than the stoichiometric air-fuel ratio, ammonia that does not contain carbon, or a substance with flame-retardant properties. However, the fuel used in the ignition device 1 of the present invention is not limited to these.

[0035] The power supply device 102 is a power supply device (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 a wire (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, one end Ep12 of the first primary coil L12, one end Ep21 of the second primary coil L21, and one end Ep22 of the second secondary coil L22 of the ignition coil 104 via the power line 150. However, as described later, by providing a first diode 131 and a second diode 132, current is prevented from flowing in the first primary coil L12 and the second secondary coil L22 due to the voltage of the power supply device 102.

[0036] ECU103 is an existing computer that comprehensively controls the operation of the transmission or engine of the vehicle body 100.

[0037] The ignition device 1 includes an ignition coil 104, a first igniter 105, a second igniter 106, a first diode 131, and a second diode 132.

[0038] Figure 2 and Figure 3 These are schematic longitudinal sectional views of the ignition coil 104. It should be noted that... Figure 2 and Figure 3 In the diagram, various components, including the power supply unit 102, other than the ignition coil 104, are shown using a dashed line. For example... Figure 2 and Figure 3As 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 has a first winding tube 41, a first primary coil L11, and a first secondary coil L12. The second coil group 50 has a second winding tube 51, a second primary coil L21, and a second secondary coil L22. The ignition coil 104, together with the first igniter 105 and the second igniter 106, is integrally built into a separately provided coil housing (not shown).

[0039] Furthermore, in the following description of the ignition coil 104, the direction parallel to the first winding tube 41 and the first central axis Bc1 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 the arc centered on the first central axis Bc1 is referred to as the "first circumferential direction." Similarly, the direction parallel to the second winding tube 51 and the second central axis Bc2 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 the arc centered on the second central axis Bc2 is referred to as the "second circumferential direction." Furthermore, the term "parallel direction" is assumed to also include substantially parallel directions, and the term "orthogonal direction" is assumed to also include substantially orthogonal directions. In this embodiment, the first central axis Bc1 and the second central axis Bc2 are substantially parallel.

[0040] The first winding tube 41 includes a first primary winding tube 411 and a first secondary winding tube 412 that are connectable to each other. The first primary winding tube 411 and the first secondary winding tube 412 extend in a cylindrical shape along the first central axis Bc1. Furthermore, the first secondary winding tube 412 is disposed on the outer side of the first primary winding tube 411 in a first radial direction. For example, resin is used as the material for the first primary winding tube 411 and the first secondary winding tube 412. The first primary coil L11 is formed by winding a conductor (hereinafter referred to as "first primary winding 811") around the outer circumferential surface of the first primary winding tube 411 in a first circumferential direction centered on the first central axis Bc1. That is, the first primary coil L11 is constituted by the first primary winding 811.

[0041] After the formation of the first primary coil L11 is completed, a first secondary winding tube 412 is arranged to cover the outer peripheral surface of the first primary coil L11 and connected to the first primary winding tube 411. Then, on the outer peripheral surface of the first secondary winding tube 412, a wire different from the first primary winding 811 (hereinafter referred to as "first secondary winding 812") is wound along the first circumferential direction centered on the first central axis Bc1 to form the first secondary coil L12. 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 to be stacked on top of each other, the ignition coil 104 containing them can be made more compact as a whole. However, the first primary coil L11 and the first secondary coil L12 are not only stacked and wound on top of each other, but can also be arranged adjacent to each other in the first axial direction.

[0042] The second winding tube 51 includes a second primary winding tube 511 and a second secondary winding tube 512 that are connectable to each other. The second primary winding tube 511 and the second secondary winding tube 512 extend in a cylindrical shape along the second central axis Bc2. Furthermore, the second secondary winding tube 512 is disposed on the outer side of the second primary winding tube 511 in the second radial direction. For example, resin is used as the material for the second primary winding tube 511 and the second secondary winding tube 512. The second primary coil L21 is formed by winding a conductor (hereinafter referred to as "second primary winding 821") along the second circumferential direction centered on the second central axis Bc2 on the outer circumferential surface of the second primary winding tube 511. That is, the second primary coil L21 is constituted by the second primary winding 821.

[0043] After the formation of the second primary coil L21 is completed, a second-stage winding tube 512 is arranged to cover the outer peripheral surface of the second primary coil L21 and connected to the second primary winding tube 511. Then, on the outer peripheral surface of the second-stage winding tube 512, a 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") in a second circumferential direction centered on the second central axis Bc2. 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 stacked manner, the ignition coil 104 containing them can be made more compact overall. However, the second primary coil L21 and the second-stage coil L22 can not only be stacked and wound on each other, but can also be arranged adjacent to each other in the second axial direction, for example.

[0044] The core 60 has a structure consisting of a first core 61, a second core 62, a core 63 connected at one end, and a core 64 connected at the other end. The first core 61, second core 62, core 63 connected at one end, and core 64 connected at the other end of the core 60 are formed, for example, from laminated steel plates of laminated silicon steel plates. The first core 61 extends in a columnar shape along a first central axis Bc1. Furthermore, the first core 61 is inserted into a space 410 inside the first primary winding tube 411 in the first radial direction. That is, the first core 61 penetrates the inside of the first primary coil L11 and the inside of the first primary coil L12. Furthermore, the second core 62 extends in a columnar shape along a second central axis Bc2. Furthermore, the second core 62 is inserted into a space 510 inside the second primary winding tube 511 in the second radial direction. That is, the second core 62 penetrates the inside of the second primary coil L21 and the inside of the second primary coil L22.

[0045] In this embodiment, the one-end connecting core 63 and the other-end connecting core 64 extend in a columnar shape in directions substantially orthogonal to the first central axis Bc1 and the second central axis Bc2, respectively. The one-end connecting core 63 connects one end 611 of the first core 61 in the first axial direction to one end 621 of the second core 62 in the second axial direction. That is, one end 611 of the first core 61 and one end 621 of the second core 62 are connected via the one-end connecting core 63. Furthermore, the other-end connecting core 64 connects the other end 612 of the first core 61 in the first axial direction to the other end 622 of the second core 62 in the second axial direction. That is, the other end 612 of the first core 61 and the other end 622 of the second core 62 are connected via the other-end connecting core 64.

[0046] This forms a closed, loop-shaped magnetic circuit with the first iron core 61, the iron core 63 connected at one end, the second iron core 62, and the iron core 64 connected at the other end connected in sequence. Furthermore, the first iron core 61 electromagnetically couples the first primary coil L11 with the first secondary coil L12. Additionally, the second iron core 62 electromagnetically couples the second primary coil L21 with the second secondary coil L22.

[0047] As described above, a power line 150, 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 ground point (ground wire) 152 via the 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 I1a (refer to...) begins to flow in the first primary coil L11. Figure 4 (t0-t1).

[0048] Furthermore, in this embodiment, the first iron core 61, extending from the other end 612 side of the first iron core 61 inside the first radial direction through the first primary coil L11, toward one end 611 side (i.e., from... Figure 2 When the first primary coil L11 is observed from below (upper side of the paper), the first primary winding 811 is wound clockwise from one end Ep11 to the other end Eg11. Therefore, when a low DC voltage from the power supply device 102 is applied to one end Ep11 of the first primary coil L11, an electromagnetic flux in that direction D1 is generated according to the right-hand screw rule. That is, when a DC voltage from the power supply device 102 is applied to the first primary coil L11, an electromagnetic flux is formed in the first iron core 61 from the other end 612 to one end 611.

[0049] Furthermore, in this embodiment, from the other end 612 side of the first iron core 61 inside the first radial direction penetrating the first primary coil L12 towards one end 611 side (i.e., from... Figure 2 When observing the primary winding L12 from below (top to bottom of the paper), the primary winding 812 is wound clockwise from one end Ep12 to the other end Eg12. Furthermore, the other end Eg12 of the primary winding L12 is connected to the spark plug 101 via the primary side ground wire Cg12. The wire diameter of the primary winding 812 is smaller than that of the first primary winding 811. Moreover, the number of turns in the primary winding 812 is approximately 100 times or more than the number of turns in the first primary winding 811 of the first primary winding L11. Therefore, as detailed later, when the first primary current I1a is disconnected, the ignition coil 104 boosts the low-voltage DC power supplied from the power supply unit 102 to several thousand to tens of thousands of volts. That is, a high voltage is induced in the primary winding L12. Then, the primary winding L12 supplies the induced high-voltage power to the spark plug 101. This generates an electric spark in spark plug 101, igniting the fuel.

[0050] In addition, such as Figure 1 As shown, the first diode 131 is connected in series with the first primary coil L12 to the primary side ground wire Cg12. The first diode 131 is positive from one end Eg12 of the first primary coil L12 toward the other end Ep12. This prevents the induced current caused by the voltage induced in the first primary coil L12 due to the gradually increasing first primary current I1a when the first primary coil L11 is energized from flowing back to the spark plug 101. In addition, as described above, a power line 150 extending from the power supply device 102 is connected to one end Ep12 of the first primary coil L12.

[0051] Furthermore, as described above, a power line 150, extending from the power supply unit 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 a ground point (ground wire) 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 unit 102 is applied to one end Ep21 of the second primary coil L21, and a gradually increasing second primary current I1b (refer to...) begins to flow in the second primary coil L21. Figure 4 (t1-t2).

[0052] Furthermore, in this embodiment, the second iron core 62, extending from the other end 622 of the second iron core 62 inside the second radial direction through the second primary coil L21, toward one end 621 (i.e., from... Figure 2 When the second primary coil L21 is observed from below (above the paper), the second primary winding 821 is wound clockwise from one end Ep21 to the other end Eg21. Therefore, when a low DC voltage from the power supply device 102 is applied to one end Ep21 of the second primary coil L21, according to the right-hand screw rule, an electromagnetic flux in the opposite direction D2, opposite to the aforementioned direction D1, is generated. That is, when a DC voltage from the power supply device 102 is applied to the second primary coil L21, an electromagnetic flux is formed in the second core 62 from the other end 622 towards one end 621.

[0053] Furthermore, in this embodiment, the second iron core 62, extending from the other end 622 of the second iron core 62 inside the second radial direction through the second secondary coil L22, toward one end 621 (i.e., from... Figure 2 When observing the secondary winding L22 (from the bottom up on the paper), the secondary winding 822 is wound clockwise from one end Ep22 to the other end Eg22. Furthermore, the other end Eg22 of the secondary winding L22 is connected to the spark plug 101 via the secondary side ground wire Cg22. The wire diameter of the secondary winding 822 is smaller than that of the second primary winding 821. Moreover, the number of turns in the secondary winding 822 is approximately 100 times or more than the number of turns in the second primary winding 821. Therefore, as detailed later, when the second primary current I1b is disconnected, the ignition coil 104 boosts the low-voltage DC power supplied from the power supply unit 102 to several thousand to tens of thousands of volts. That is, a high voltage is induced in the secondary winding L22. And the secondary winding L22 supplies the induced high-voltage power to the spark plug 101. This allows the electric spark generated in spark plug 101 to be maintained for a longer period of time.

[0054] In addition, such as Figure 1As shown, the second diode 132 is connected in series with the secondary primary coil L22 to the secondary primary side ground wire Cg22. The second diode 132 is positively oriented from one end Eg22 of the secondary primary coil L22 towards one end Ep22. This prevents the induced current caused by the voltage induced in the secondary primary coil L22 due to the gradually increasing secondary primary current I1b when the secondary primary coil L21 is energized from flowing back to the spark plug 101. Furthermore, as described above, a power line 150 extending from the power supply device 102 is connected to one end Ep22 of the secondary primary coil L22.

[0055] As described above, in this embodiment, in an ignition coil 104, a first iron core 61 passing through the inner side of the first coil group 40 and a second iron core 62 passing through the inner side of the second coil group 50 are connected to each other to form a closed magnetic circuit. Therefore, compared to the case where a closed magnetic circuit is formed in each coil group 40, 50, the ignition coil 104 including the iron core 60 can be miniaturized overall. Furthermore, by arranging the iron core 60 in this way, as described later, the magnetic flux generated in the closed magnetic circuit can be increased, and the ignition energy supplied to the spark plug 101 can be increased, thus achieving high energy output. As a result, the ignition device 1 including the ignition coil 104 can be more easily mounted in an internal combustion engine. In addition, since the number of parts can be reduced, it helps to reduce the overall manufacturing cost of the device.

[0056] 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. Furthermore, 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. Additionally, the first igniter 105 can also be integrated with the electronic circuitry of the ECU 103.

[0057] As the first switching element 71, an insulated gate bipolar transistor (IGBT) is used, for example. The first switching element 71 is inserted between the other end Eg11 of the first primary coil L11 and the ground point (ground wire) 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 the ground point (ground wire) 152. The gate (G) of the first switching element 71 is connected to the first driver IC 72.

[0058] Therefore, the first switching element 71 can switch the energization or de-energization of the first primary current I1a flowing from the power supply device 102 to the first primary coil L11. When the first switching element 71 is in the closed state, the first primary current I1a flows from the power supply device 102 to the first primary coil L11. When the first switching element 71 is in the open state, the first primary current I1a flowing in the first primary coil L11 is de-energized. Other types of transistors may also be used as the first switching element 71.

[0059] 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 may include, 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 ignite the spark plug 101.

[0060] 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. Furthermore, the second igniter 106 is electrically connected to the ECU 103 and receives signals 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. Additionally, the second igniter 106 can also be integrated with the electronic circuitry of the ECU 103.

[0061] As the second switching element 73, an insulated gate bipolar transistor (IGBT) is used, for example. The second switching element 73 is inserted between the other end Eg21 of the second primary coil L21 and the ground point (ground wire) 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 the ground point (ground wire) 152. The gate (G) of the second switching element 73 is connected to the second driver IC 74.

[0062] Therefore, the second switching element 73 can switch the energization or de-energization of the second primary current I1b flowing from the power supply device 102 to the second primary coil L21. When the second switching element 73 is in the closed state, the second primary current I1b flows from the power supply device 102 to the second primary coil L21. When the second switching element 73 is in the open state, the second primary current I1b flowing in the second primary coil L21 is de-energized. Other types of transistors may also be used as the second switching element 73.

[0063] The second drive IC 74 controls the switching of the second switching element 73 according to 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 may include, for example, logic circuits, processors, CPLDs (complex programmable logic devices), FPGAs (field-programmable gate arrays), or ASICs (application-specific integrated circuits). The logic device is used to perform calculations to activate the ignition device 1 and ignite the spark plug 101.

[0064] <1-2. Operation of the ignition device>

[0065] Next, the operation of ignition device 1 will be explained. Figure 4 It is a graph showing, in time sequence, the waveforms of the first EST signal S1, the first primary current I1a flowing in the first primary coil L11, the first primary current I2a flowing in the first primary coil L12, the second EST signal S2, the second primary current I1b flowing in the second primary coil L21, the second primary current I2b flowing in the second primary coil L22, and the waveforms of the first primary current I2a and the second primary current I2b added together when the ignition device 1 is activated.

[0066] It should be noted that, in Figure 4In the diagram, for the first primary current I1a, the direction of the first primary coil L11 from one end Ep11 to the other end Eg11 is shown as positive. Similarly, for the first primary current I2a, the direction of the first primary coil L12 from the other end Eg12 to one end Ep12 is shown as negative. Furthermore, for the second primary current I1b, the direction of the second primary coil L21 from one end Ep21 to the other end Eg21 is shown as positive. And for the second primary current I2b, the direction of the second primary coil L22 from the other end Eg22 to one end Ep22 is shown as negative.

[0067] like Figure 4 As shown, when the ignition device 1 is activated, firstly, at time t0, the signal level of the first EST signal S1 sent from the ECU 103 to the first drive IC 72 is set from L to H. Thus, the first drive IC 72 switches the first switching element 71 from an open state to a closed state according to the first EST signal S1. This applies a low DC voltage from the power supply device 102 to one end Ep11 of the first primary coil L11. Furthermore, a first primary current I1a flows in the first primary winding 811 forming the first primary coil L11, generating a magnetomotive force in the first primary coil L11. Hereinafter, this process of generating a magnetomotive force by the flow of the first primary current I1a in the first primary coil L11 will be referred to as "primary energization control".

[0068] Here, as described above, when viewed from the other end 612 side of the first iron core 61 towards the other end 611 side, the first primary winding 811 is wound clockwise from one end Ep11 towards the other end Eg11. Therefore, by applying a low DC voltage from the power supply device 102 to one end Ep11 of the first primary coil L11, a magnetic flux in that direction D1 is generated according to the right-hand screw rule. That is, an electromagnetic flux is generated in the first iron core 61 from the other end 612 to one end 611 in a direction D1. Corresponding to this electromagnetic flux A magnetic field acts on the iron core 60 ( Figure 5 ).

[0069] Furthermore, at this time, minute induced electromotive forces are induced in the first primary coil L12, which is electromagnetically coupled to the first primary coil L11 via the iron core 60, and in the second primary coil L22, which is also electromagnetically coupled to the first primary coil L11 via the iron core 60. Here, as described above, when viewed from the other end 612 side of the first iron core 61 towards the other end 611 side, the first primary winding 812 is wound clockwise from one end Ep12 to the other end Eg12. Therefore, when an induced current (first primary current I2a) is to flow according to this induced electromotive force, this induced current (first primary current I2a) will flow in the reverse direction in the first diode 131 connected in series with the first primary coil L12, and is therefore blocked by the first diode 131. As a result, no induced current (first primary current I2a) flows in the first primary coil L12 (see reference). Figure 4 The time t0-t1 for the first stage current I2a.

[0070] On the other hand, when viewed from the other end 622 side of the second core 62 towards one end 621, the second stage winding 822 is wound clockwise from one end Ep22 to the other end Eg22. Therefore, when an induced current (secondary stage current I2b) is desired to flow according to the induced electromotive force, the induced current (secondary stage current I2b) flows in the forward direction in the second diode 132 connected in series with the secondary stage coil L22, and is therefore not obstructed by the second diode 132. As a result, an induced current (secondary stage current I2b) flows in the secondary stage coil L22 (see reference). Figure 4 The time of the second-stage current I2b is t0-t1. Among them, the induced current (second-stage current I2b) is weak and in principle will not generate an electric spark in the spark plug 101.

[0071] After the initial power-on control is performed, at time t1, simultaneously, the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from H to L, and 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, disconnecting the primary current (first primary current I1a) 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, a current equivalent to the aforementioned electromagnetic flux is generated through mutual induction. One direction D1 opposite direction Figure 6 The disconnected magnetic flux in the other direction D2 is shown. And a large induced electromotive force is generated. At this time, the voltage applied to the other end Eg12 of the primary coil L12 reaches several thousand to tens of thousands of V relative to the grounding point (ground wire) 152.

[0072] Here, as described above, when viewed from the other end 612 side of the first iron core 61 towards the one end 611 side, the first stage winding 812 is wound clockwise from one end Ep12 towards the other end Eg12. Therefore, when an induced current (first stage current I2a) is desired to flow according to the induced electromotive force, the induced current (first stage current I2a) flows in the forward direction in the first diode 131 connected in series with the first stage coil L12, and is therefore not obstructed by the first diode 131. As a result, a large induced current (second stage current I2b) flows in the first stage coil L12 (see reference). Figure 4 The timing of the first primary current I2a (t1-t2). As a result, an electric spark can be generated in the spark plug 101 connected to the other end Eg12 of the first primary coil L12, igniting the fuel. Hereinafter, the process of discharging in the gap d of the spark plug 101 by disconnecting the first primary current I1a flowing in the first primary coil L11, inducing a high voltage at the other end Eg12 of the first primary coil L12, and thus discharging in the gap d of the spark plug 101 is called "discharge control".

[0073] Furthermore, simultaneously with the initiation of the discharge control by the first drive IC 72, the second drive IC 74 switches the second switching element 73 from an open 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. Moreover, a second primary current I1b flows in the second primary winding 821 forming the second primary coil L21, generating a magnetomotive force in the second primary coil L21. That is, the second drive IC 74 performs primary energization control to generate a magnetomotive force by allowing the second primary current I1b to flow in the second primary coil L21. Here, as described above, when viewed from the other end 622 side of the second iron core 62 towards the one end 621 side, the second primary winding 821 is wound clockwise from one end Ep21 towards the other end Eg21. Therefore, by applying a low DC voltage from the power supply device 102 to one end Ep21 of the second primary coil L21, a magnetic flux in the other direction D2 is generated according to the right-hand screw rule. That is, an electromagnetic flux is generated in the second iron core 62 from the other end 622 to one end 621 in the other direction D2. With the electromagnetic flux The corresponding magnetic field acts on the iron core 60 ( Figure 6 ).

[0074] Here, as described above, in the core 60 of the present invention, only one annular closed magnetic circuit is formed, connected in the order of first core 61, one-end connected core 63, second core 62, and the other-end connected core 64. Furthermore, the disconnected magnetic flux generated during the discharge control based on the first drive IC 72... and the electromagnetic flux generated by energizing the second primary coil L21 In this closed magnetic circuit, the magnetic flux is directed in the same direction D2. Therefore, during discharge control based on the first drive IC72, the second primary coil L21 is energized by the control based on the second drive IC74, thereby increasing the magnetic flux generated in the closed magnetic circuit of the core 60. Hereinafter, the process in which the second drive IC74 sets the second switching element 73 to the closed state when the first drive IC72 performs discharge control, thereby increasing the magnetic flux generated in the closed magnetic circuit of the core 60 by allowing the second primary current I1b to flow in the second primary coil L21, is referred to as "push-up control". That is, the second drive IC74 performs this "push-up control" while simultaneously performing primary energization control to generate a magnetomotive force by allowing the second primary current I1b to flow in the second primary coil L21.

[0075] Thus, during the timing of the discharge control of the first primary coil L11, the second primary current I1b flows in the second primary coil L21, amplifying the magnetic flux generated in the closed magnetic circuit of the iron core 60, thereby increasing the current supplied to the spark plug 101 and the ignition energy (see reference). Figure 4 The time t1-t2 of the first stage current I2a. As a result, even when burning lean fuel or fuels with poor flammability such as ammonia, the flame generated around the spark plug 101 can be maintained for a longer period of time.

[0076] Furthermore, after the second drive IC74 performs boost control, at time t2, simultaneously setting the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 from H to L, the signal level of the first EST signal S1 sent from the first drive IC72 of ECU103 from L to H. Thus, the second drive IC74 switches the second switching element 73 from a closed state to an open state, disconnecting the primary current (second primary current I1b) 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... Figure 6 Electromagnetic flux The other direction D2 is the opposite direction. Figure 7 The disconnected magnetic flux in direction D1 is shown. And it induces a large electromotive force. At this time, the voltage applied to the other end Eg22 of the secondary coil L22 reaches several thousand to tens of thousands of negative V relative to the grounding point (ground wire) 152.

[0077] Here, as described above, when viewed from the other end 622 side of the second core 62 towards one end 621, the second stage winding 822 is wound clockwise from one end Ep22 to the other end Eg22. Therefore, when an induced current (secondary stage current I2b) is expected to flow corresponding to the induced electromotive force, this induced current (secondary stage current I2b) flows forward in the second diode 132 connected in series with the secondary stage coil L22, and is therefore not obstructed by the second diode 132. As a result, a large induced current (secondary stage current I2b) flows in the secondary stage coil L22 (see reference). Figure 4 The second stage current I2b occurs between times t2 and t3. As a result, the spark generated around the spark plug 101 connected to the other end Eg22 of the second stage coil L22 can be maintained for a longer period of time. That is, after the second drive IC 74 performs push-up control, at time t2, by switching the second switching element 73 to the off state, a high voltage is induced in the other end Eg22 of the second stage coil L22, thereby performing discharge control to continuously discharge in the gap d of the spark plug 101.

[0078] Furthermore, simultaneously with the start of the discharge control by the second drive IC 74, at time t2, the first drive IC 72 switches the first switching element 71 from the open state to the closed state. As a result, a low DC voltage from the power supply device 102 is applied to one end Ep11 of the first primary coil L11. A first primary current I1a flows in the first primary winding 811 forming the first primary coil L11, generating a magnetomotive force in the first primary coil L11. Here, as described above, when viewed from the other end 612 side of the first iron core 61 towards one end 611, the first primary winding 811 is wound clockwise from one end Ep11 towards the other end Eg11. Therefore, by applying a low DC voltage from the power supply device 102 to one end Ep11 of the first primary coil L11, a electromagnetic flux in the aforementioned direction D1 is generated according to the right-hand screw rule. That is, the first iron core 61 generates an electromagnetic flux from the other end 612 to one end 611 in a direction D1. With the electromagnetic flux The corresponding magnetic field acts on the iron core 60 ( Figure 7 ).

[0079] Here, the aforementioned disconnected magnetic flux With the electromagnetic flux In the closed magnetic circuit formed in the iron core 60, the magnetic flux generated in the closed magnetic circuit is directed in the same direction D1. Therefore, during discharge control based on the second drive IC 74, the first primary coil L11 is energized using the control based on the first drive IC 72, thereby amplifying the magnetic flux generated in the closed magnetic circuit of the iron core 60. Thus, in this embodiment, during the timing of discharge control by the second drive IC 74, the first switch element 71 is reset to the closed state by the first drive IC 72, thereby increasing the magnetic flux generated in the closed magnetic circuit of the iron core 60 by allowing the first primary current I1a to flow in the first primary coil L11. As a result, the current supplied to the spark plug 101 and the ignition energy (see reference) can be increased. Figure 4 The second stage current I2b occurs at times t2-t3. As a result, even when burning lean fuels or fuels with poor flammability such as ammonia, the flame generated around the spark plug 101 can be maintained for a longer period of time.

[0080] Furthermore, in this embodiment, at time t3, while the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from H to L, the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from L to H. Additionally, at time t4, while the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from H to L, the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from L to H. Furthermore, at time t5, while the signal level of the first EST signal S1 sent from ECU103 to the first drive IC72 is changed from H to L, the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from L to H. Finally, at time t6, the signal level of the second EST signal S2 sent from ECU103 to the second drive IC74 is changed from H to L.

[0081] As described above, in this embodiment, after performing the primary power-on control, the first drive IC 72 performs discharge control, and then repeatedly alternates between push-up control and discharge control. That is, after performing the primary power-on control, the first drive IC 72 repeatedly alternates between discharge control and push-up control. Furthermore, when the first drive IC 72 initially performs discharge control, the second drive IC 74 performs primary power-on control simultaneously with push-up control, and then, in conjunction with the control switching based on the first drive IC 72, repeatedly alternates between discharge control and push-up control. That is, whenever the first drive IC 72 performs discharge control, the second drive IC 74 performs the aforementioned push-up control, and whenever the first drive IC 72 performs push-up control, the second drive IC 74 performs the aforementioned discharge control. By performing such control, even when burning lean fuel or ammonia, a fuel with poor flammability, the flame generated around the spark plug 101 can be maintained for a longer period. The number of times the first drive IC 72 and the second drive IC 74 switch between each control can be appropriately determined.

[0082] <2. Variations>

[0083] The exemplary embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

[0084] In the above embodiment, a low DC voltage from the power supply device 102 is applied to one end of each coil, and the other end of each coil is connected to a ground point. Furthermore, when viewed from the other end of the iron core penetrating the inner side of each coil towards one end, the windings forming each coil are wound clockwise from one end to the other. However, it is also possible to apply a low DC voltage from the power supply device 102 to the other end of each coil, and connect one end of each coil to a ground point. In this case, when viewed from the other end of the iron core penetrating the inner side of each coil towards one end, the windings forming each coil are wound counterclockwise from one end to the other.

[0085] 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 or industrial machinery such as generators. It is a device used to generate an electric spark from the spark plug of an internal combustion engine to ignite the fuel.

[0086] The shape or structure of the ignition coil and ignition device described above can be appropriately modified without departing from the spirit of the invention. Furthermore, the elements appearing in the above embodiments or variations can be appropriately combined without creating contradictions.

[0087] Explanation of reference numerals in the attached figures

[0088] 1 Ignition device

[0089] 60 iron core

[0090] 61 First Iron Core

[0091] 62 Second Iron Core

[0092] 71 First Switching Element

[0093] 72 First Driver IC (First Control Unit)

[0094] 73 Second Switching Element

[0095] 74 Second Driver IC (Second Control Unit)

[0096] 101 Spark Plug

[0097] 102 Power Supply Unit

[0098] 104 Ignition Coil

[0099] 105 First Ignition Device

[0100] 106 Second Ignition Device

[0101] 150 power cord

[0102] One end of 611 (the first iron core)

[0103] The other end of 612 (the first iron core)

[0104] 621 (one end of the second core)

[0105] The other end of 622 (the second core)

[0106] 811 First Primary Winding

[0107] 812 Primary winding

[0108] 821 Second Primary Winding

[0109] 822 Secondary winding

[0110] D (spark plug gap)

[0111] The other end of Eg11 (the first primary coil)

[0112] Eg12 (the other end of the primary coil)

[0113] The other end of Eg21 (the second primary coil)

[0114] The other end of Eg22 (secondary coil)

[0115] One end of Ep11 (the first primary coil)

[0116] One end of Ep12 (the first stage coil)

[0117] One end of Ep21 (the second primary coil)

[0118] One end of Ep22 (the second stage coil)

[0119] L11 First primary coil

[0120] L12 First stage coil

[0121] L21 Second Primary Coil

[0122] L22 Secondary coil

Claims

1. An ignition coil for use in an internal combustion engine, having: The first primary coil, consisting 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; The first iron core passes through the inner side of the first primary coil and the inner side of the first secondary coil, and electromagnetically couples the first primary coil with the first secondary coil. The second primary coil, consisting of a second primary winding, has the DC voltage applied to one end and the other end connected to a ground point. The second-stage coil is composed of second-stage windings; as well as The second iron 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 and the second secondary coil. By connecting one end of the first iron core to one end of the second iron core, and connecting the other end of the first iron core to the other end of the second iron core, a closed magnetic circuit is formed. When the DC voltage is applied to the first primary coil, a magnetic flux is formed in the first iron core from one end to the other. When the DC voltage is applied to the second primary coil, a magnetic flux is formed in the second iron core from one end to the other.

2. An ignition device, comprising: The ignition coil as described in claim 1; The power supply device 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 is inserted between the other end of the first primary coil and the ground point, and 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, 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. The 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 The spark plug ignites fuel by discharging in the gap based on the high voltage induced at the other end of the first stage coil and / or the high voltage induced at the other end of the second stage coil.

3. The ignition device according to claim 2, The first control unit performs: Primary energization control involves setting the first switching element to the closed state, allowing the first primary current to flow in the first primary coil, thereby generating a magnetomotive force. as well as Discharge control involves switching the first switching element to the off state after the primary energization control, inducing a high voltage at the other end of the primary coil, thereby discharging in the gap of the spark plug. The second control unit performs: The push control, during the timing of the discharge control performed by the first control unit, sets the second switching element to a closed state, thereby allowing the second primary current to flow in the second primary coil and increasing the magnetic flux generated in the closed magnetic circuit; as well as Discharge control involves switching the second switching element to the off state after the push-up control, thereby inducing a high voltage at the other end of the secondary coil and continuing discharge in the spark plug gap. The first control unit further performs: The push control, in the timing of the discharge control performed by the second control unit, increases the magnetic flux generated in the closed magnetic circuit by setting the first switching element to the closed state and allowing the first primary current to flow in the first primary coil.

4. The ignition device according to claim 3, After performing the primary power-on control, the first control unit repeatedly and alternately performs the discharge control and the boost control. Whenever the first control unit performs the discharge control, the second control unit performs the boost control; whenever the first control unit performs the boost control, the second control unit performs the discharge control.

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