Ignition device for internal combustion engine

Abstract

The present application provides an ignition device for an internal combustion engine, which more reliably ignites fuel and quickly converges residual energy. An ignition device for an internal combustion engine (1) has a transformer (20) having an electromagnetically coupled primary coil (L1) and a secondary coil (L2), an energization control section (30) that controls energization to the primary coil, a first spark plug (91) electrically connected between a high-voltage side terminal (21) of the secondary coil and ground, and a second spark plug (92) electrically connected between a low-voltage side terminal (22) of the secondary coil and ground. The first spark plug and the second spark plug are disposed in the same combustion chamber of the internal combustion engine. Thus, by discharging at both spark plugs, fuel can be more reliably ignited. In addition, by the residual energy of the first spark plug and the residual energy of the second spark plug canceling each other, the residual energy can be quickly converged.

Description

Technical Field

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

[0002] In an internal combustion engine ignition coil, after current is passed through the primary coil of the coil assembly to generate a magnetic field, the current is cut off, thereby generating a high voltage in the secondary coil through self-induction. This high voltage in the secondary coil then discharges onto the spark plug.

[0003] For example, Patent Document 1 describes a conventional ignition device for internal combustion engines. Figure 4 The diagram shows a simplified circuit diagram of a conventional ignition device 1X for an internal combustion engine, which is the same as the ignition device for an internal combustion engine described in Patent Document 1. Additionally, Figure 5 An example is shown of the potential difference (secondary voltage) across the secondary coil of such an ignition device 1X for an internal combustion engine.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-82193 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In such Figure 4 and Figure 5 In the conventional ignition system 1X for internal combustion engines shown, the igniter Ig is turned on to supply voltage to the primary coil Co1 from the power supply Ba (energizing period T1). After supplying voltage to the primary coil Co1 for a certain period of time, the igniter Ig is turned off. As a result, a high voltage is generated in the secondary coil Co2 through self-induction, with the direction opposite to the voltage during energizing period T1, thereby causing a discharge at the spark plug Pg (discharge period T2).

[0009] During discharge, charge accumulates in the capacitive components surrounding the spark plug Pg. This leads to the following problems: Figure 5 As shown, during the standby period T3 after discharge, the convergence of the secondary voltage takes time due to the residual energy.

[0010] In addition, in recent years, the use of non-flammable fuels such as hydrogen (which is more flammable than traditional fuels) and ammonia (which is less flammable than traditional fuels) has been explored. The aim is to find a technology that can reliably ignite fuels even when multiple fuels with different ignition ease and combustion speed are mixed together.

[0011] The purpose of this invention is to provide a technology that enables fuel to ignite more reliably and allows residual energy to be collected more quickly.

[0012] Solution for solving the problem

[0013] To address the aforementioned problems, the first invention of this application is an ignition device for an internal combustion engine, comprising: a transformer having an electromagnetically coupled primary coil and a secondary coil; an energizing control unit for controlling the energizing of the primary coil; a first spark plug electrically connected between the high-voltage side terminal of the secondary coil and ground; and a second spark plug electrically connected between the low-voltage side terminal of the secondary coil and ground, wherein the first spark plug and the second spark plug are disposed in the same combustion chamber of the internal combustion engine.

[0014] Regarding the second invention of this application, in the ignition device for an internal combustion engine of the first invention, the fuel gas introduced into the combustion chamber is a mixture of multiple fuels.

[0015] Regarding the third invention of this application, in the ignition device for an internal combustion engine of the second invention, the fuel gas introduced into the combustion chamber contains hydrogen.

[0016] Regarding the fourth invention of this application, in the ignition device for an internal combustion engine of the second or third invention, the fuel gas introduced into the combustion chamber contains a flame-retardant fuel.

[0017] Regarding the fifth invention of this application, in the ignition device for an internal combustion engine of the fourth invention, the flame-retardant fuel is ammonia.

[0018] The sixth invention of this application is an ignition device for an internal combustion engine, comprising: a transformer having an electromagnetically coupled primary coil and two secondary coils; an energizing control unit for controlling the energizing of the primary coil; a first spark plug electrically connected between a high-voltage side terminal of one of the secondary coils and ground; a second spark plug electrically connected between a low-voltage side terminal of one of the secondary coils and ground; a third spark plug electrically connected between a high-voltage side terminal of the other of the secondary coils and ground; and a fourth spark plug electrically connected between a low-voltage side terminal of the other of the secondary coils and ground, wherein the first spark plug, the second spark plug, the third spark plug, and the fourth spark plug are disposed in the same combustion chamber of the internal combustion engine.

[0019] The effects of the invention

[0020] According to the first to sixth inventions of this application, fuel can be reliably ignited and residual energy can be quickly collected.

[0021] The second to fifth inventions of this application are particularly useful because there is a need for more reliable ignition of fuel. Attached Figure Description

[0022] Figure 1This is a circuit diagram of the ignition device for an internal combustion engine according to the first embodiment.

[0023] Figure 2 This is a diagram showing an example of the secondary voltage waveform in the ignition device for an internal combustion engine according to the first embodiment.

[0024] Figure 3 This is a circuit diagram of the ignition device for an internal combustion engine according to the second embodiment.

[0025] Figure 4 This is a circuit diagram of the ignition device used in traditional internal combustion engines.

[0026] Figure 5 This is a diagram showing an example of the secondary voltage waveform in a conventional ignition system for internal combustion engines. Detailed Implementation

[0027] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

[0028] <1. First Implementation Method>

[0029] <1-1. Structure of Ignition Device for Internal Combustion Engines>

[0030] The structure of an ignition device 1 for an internal combustion engine, which is one embodiment of the present invention, will be described with reference to the accompanying drawings. Figure 1 This is a circuit diagram of the ignition device 1 for an internal combustion engine according to the first embodiment. Furthermore, in Figure 1 The detailed circuit of the primary side is omitted in the text.

[0031] The ignition device 1 for internal combustion engines in this embodiment, for example, is mounted on the body of a vehicle such as an automobile, and is a device that applies a high voltage to generate a spark discharge for the spark plugs 91 and 92 of the internal combustion engine. Figure 1 As shown, the ignition device 1 for an internal combustion engine includes a transformer 20, an energizing control unit 30, a first spark plug 91, and a second spark plug 92.

[0032] In the case of using an internal combustion engine ignition device 1 in a multi-cylinder internal combustion engine, the battery 31 and ECU 32 of the power supply control unit 30 (described later) can also be shared by multiple cylinders. On the other hand, the transformer 20, the igniter 33 of the power supply control unit 30 (described later), the first spark plug 91, and the second spark plug 92 are equipped for each cylinder. For example, in a four-cylinder internal combustion engine, there is one battery 31, one ECU 32, and four sets of transformers 20, igniters 33, first spark plugs 91, and second spark plugs 92.

[0033] In the internal combustion engine using the ignition device 1 for internal combustion engines according to this embodiment, the combustion gas introduced into the combustion chamber of each cylinder is a mixture of various fuels. This mixture contains, for example, hydrogen and ammonia, which is a difficult-to-ignite fuel. Hydrogen is easier to ignite and burns faster than conventional fuels such as gasoline. On the other hand, ammonia is less ignitable and burns slower than conventional fuels such as gasoline. Therefore, when using a mixture of fuels with different ignition ease and combustion speed, it is necessary to perform ignition more reliably and to more quickly collect residual energy around the spark plug compared to conventional ignition devices.

[0034] Transformer 20 has an electromagnetically coupled primary coil L1 and a secondary coil L2. The secondary coil L2 has more turns than the primary coil L1. The secondary coil L2 has a high-voltage side terminal 21 and a low-voltage side terminal 22 at both ends.

[0035] The power supply control unit 30 controls the energization of the primary coil L1. The power supply control unit 30 includes a battery 31, an ECU (Engine Control Unit) 32, and an igniter 33.

[0036] Battery 31 is a power supply device (storage battery) capable of charging and discharging DC power. In this embodiment, battery 31 is electrically connected to the primary coil L1 of transformer 20 and igniter 33. Battery 31 supplies DC voltage to the primary coil L1 of transformer 20 and igniter 33.

[0037] The ECU 32 is an existing computer that performs comprehensive control over the vehicle's transmission, airbag operation, and other functions. The ECU 32 outputs ignition signals to the ignition coil 33 to control its on / off operation.

[0038] Ignition device 33 is used to control the energization of the primary coil L1. Ignition device 33 is, for example, a switching element such as an IGBT (Insulated Gate Bipolar Transistor). Ignition device 33 is turned on / off according to the ignition signal supplied from ECU 32, thereby controlling the energization of the primary coil L1.

[0039] The first spark plug 91 and the second spark plug 92 are disposed inside the combustion chamber of the internal combustion engine and are devices used to achieve ignition within the combustion chamber. The spark plug specifications and spark plug gap of the first spark plug 91 are the same as those of the second spark plug 92. The first spark plug 91 and the second spark plug 92 are disposed separately within a combustion chamber.

[0040] The first spark plug 91 is electrically connected between the high-voltage side terminal 21 of the secondary coil L2 of the transformer 20 and ground. That is, one end of the first spark plug 91 is connected to the high-voltage side terminal 21, and the other end of the first spark plug 91 is grounded.

[0041] The second spark plug 92 is electrically connected between the low-voltage side terminal 22 of the secondary coil L2 of the transformer 20 and ground. That is, one end of the second spark plug 92 is connected to the low-voltage side terminal 22, and the other end of the second spark plug 92 is grounded.

[0042] When the ignition switch 33 is turned on according to the ignition signal from the ECU 32, a voltage is applied to both ends of the primary coil L1, thereby generating a current in the primary side circuit. This creates a magnetic flux within the transformer 20. Subsequently, when the ignition switch 33 is turned off according to the ignition signal from the ECU 32, an electromagnetic induction generated by the magnetic flux formed in the transformer 20 induces a high voltage at both ends of the secondary coil L2, in the opposite direction to the voltage supplied by the battery 31. As a result, the high-voltage side terminal 21 becomes larger and negatively potentialed relative to the low-voltage side terminal 22.

[0043] As a result, the high-voltage side terminal 21 connected to the first spark plug 91 becomes a negative potential with a large absolute value, and the low-voltage side terminal 22 connected to the second spark plug 92 becomes a positive potential with a large absolute value. Therefore, a discharge occurs at the gap between the first spark plug 91 and the gap between the second spark plug 92, thereby generating a spark. Thus, the fuel filled in the internal combustion engine is ignited.

[0044] <1-2. Changes in the secondary voltage of the ignition system for internal combustion engines>

[0045] Next, refer to Figure 2 This will be used to explain the voltage change on the secondary side of the ignition device 1 for internal combustion engines in this embodiment. Figure 2 This is a diagram illustrating an example of the secondary voltage waveform in the ignition device 1 for an internal combustion engine according to this embodiment. Specifically, Figure 2 This is a simulation result for the ignition device 1 for an internal combustion engine. Hereinafter, the voltage at the high-voltage side terminal 21 of the secondary coil L2 will be set as the first spark plug voltage V1, and the voltage at the low-voltage side terminal 22 of the secondary coil L2 will be set as the second spark plug voltage V2.

[0046] In an internal combustion engine, the intake, compression, combustion, and exhaust strokes are performed by opening and closing the intake / exhaust valves and discharging the spark plugs in coordination with the rotation of the crankshaft. The ignition device 1 for the internal combustion engine ignites the compressed fuel gas in the combustion chamber by discharging the spark plugs near the top dead center of the compression stroke. The ignition device 1 for the internal combustion engine performs the following actions in coordination with the piston movement to discharge the spark plugs 91 and 92:

[0047] During the energizing period T1: Energizing the primary coil L1

[0048] During discharge T2: Discharge at spark plugs 91 and 92

[0049] During standby, T3: Residual energy recovery

[0050] Here, firstly, refer to Figure 5 To explain Figure 4 The variation of the secondary voltage Vx in the conventional internal combustion engine ignition device 1X is shown. In the internal combustion engine ignition device 1X, the spark plug Pg is connected between the high-voltage side terminal of the secondary coil Co2 and ground. Hereinafter, the voltage at the high-voltage side terminal of the secondary coil Co2 will be referred to as the secondary voltage Vx. That is, the secondary voltage Vx is the voltage applied across the spark plug Pg. Immediately after the internal combustion engine ignition device 1 is started, that is, before the energizing period T1, the secondary voltage Vx is 0 [V].

[0051] When the energizing period T1 begins and the primary coil Co1 is energized, a voltage is generated in the secondary coil Co2 as voltage is supplied to the primary coil Co1 (the voltage at the time of energization). Figure 5 (Va[V] in the transformer). As the primary coil Co1 continues to be energized, the secondary voltage Vx gradually decreases from the voltage at the time of energization as magnetic flux is formed within the transformer.

[0052] When the energizing period T1 ends, thus cutting off the power supply to the primary coil Co1, a high voltage is generated in the secondary coil Co2, in the opposite direction (negative) to the voltage during energization. This applies a high voltage to the spark plug Pg. Figure 5 The discharge occurs at the gap of spark plug Pg (during discharge period T2). Subsequently, as the discharge continues, the magnetic flux formed in the transformer weakens, and the absolute value of the secondary current (the current flowing in the secondary coil Co2 and spark plug Pg) gradually decreases. Thus, the discharge at spark plug Pg ends.

[0053] During discharge T2, charge accumulates in the capacitive components surrounding spark plug Pg due to the current flowing through it. Specifically, positive charge accumulates on the ground side of spark plug Pg, and negative charge accumulates on the secondary coil Co2 side.

[0054] Therefore, during standby time T3, the secondary voltage Vx temporarily becomes negative due to the residual energy accumulated in the parasitic capacitance around the spark plug Pg. The secondary voltage Vx converges towards 0 [V] as the residual energy converges.

[0055] Next, refer to Figure 2 This will explain the changes in the first spark plug voltage V1 and the second spark plug voltage V2 in the ignition device 1 for internal combustion engines of this embodiment.

[0056] First, immediately after the start of use of the internal combustion engine ignition device 1, i.e. before the energization period T1, there is no charge accumulation in the secondary coil L2, the first spark plug 91, and the second spark plug 92, and the potential in all these circuits is 0 [V]. That is, the first spark plug voltage V1 and the second spark plug voltage V2 are also 0 [V].

[0057] When energization begins during period T1 and the primary coil L1 is energized, a potential difference is generated across the secondary coil L2 as voltage is supplied to the primary coil L1. Here, when the voltage generated in the secondary coil L2 immediately after energization begins is set to 2 × Von [V], the other end of the first spark plug 91 and the other end of the second spark plug 92 are grounded and are 0 [V]. Therefore, the first spark plug voltage V1 becomes Von [V], and the second spark plug voltage V2 becomes -Von [V]. The voltage generated at the beginning of energization during period T1 is called the on-time voltage.

[0058] As the primary coil L1 continues to be energized, the potential difference across the secondary coil L2 gradually decreases from 2 × Von[V] as magnetic flux is formed within the transformer 20. Consequently, the absolute values ​​of the first spark plug voltage V1 and the second spark plug voltage V2 also gradually decrease from Von[V].

[0059] When the energizing period T1 ends and the power supply to the primary coil L1 is cut off, a high voltage is generated in the secondary coil L2 in the opposite direction to the voltage during energization. This applies a high negative voltage to the first spark plug 91, resulting in a discharge at the gap of the first spark plug 91. Conversely, a high positive voltage is applied to the second spark plug 92, resulting in a discharge at the gap of the second spark plug 92 (during discharge period T2).

[0060] Here, the maximum voltage generated in the secondary coil L2 during the discharge period T2 is set to -2×Vd[V]. Therefore, at the beginning of the discharge period T2, the first spark plug voltage V1 becomes -Vd[V], and the second spark plug voltage V2 becomes Vd[V].

[0061] During discharge T2, due to the current flowing through the first spark plug 91 and the second spark plug 92, charge accumulates in the capacitive components around the first spark plug 91 and the second spark plug 92. Specifically, positive charge accumulates on the other end side (ground side) of the first spark plug 91, and negative charge accumulates on one end side (high-voltage terminal 21 side). On the other hand, negative charge accumulates on the other end side (ground side) of the second spark plug 92, and positive charge accumulates on one end side (low-voltage terminal 22 side).

[0062] When the discharge period T2 ends and the standby period T3 begins, the charge moves in such a way that the charge stored in the capacitor component around the first spark plug 91 cancels out the charge stored in the capacitor component around the second spark plug 92. Thus, the residual energy stored in the parasitic capacitance around the first spark plug 91 and the residual energy stored in the parasitic capacitance around the second spark plug 92 are both dissipated.

[0063] Here, as described above, the spark plug specifications and spark plug gap of the first spark plug 91 are the same as those of the second spark plug 92. Therefore, the electrical conditions of the first spark plug 91 are identical to those of the second spark plug 92. Consequently, the residual energy stored in the parasitic capacitance surrounding the first spark plug 91 is approximately equal to the residual energy stored in the parasitic capacitance surrounding the second spark plug 92. Thus, the residual energy of both is well balanced and canceled out.

[0064] Furthermore, due to the movement of charge between the parasitic capacitance around the first spark plug 91 and the parasitic capacitance around the second spark plug 92, current temporarily flows in the secondary coil L2, causing the first spark plug voltage V1 and the second spark plug voltage V2 to oscillate temporarily.

[0065] Through this movement of charge, most of the residual energy stored in the parasitic capacitance around the first spark plug 91 and the parasitic capacitance around the second spark plug 92 is immediately eliminated after the discharge period T2 ends, leaving very little remaining. Furthermore, due to the residual energy, the first spark plug voltage V1 becomes a relatively small negative potential, and the second spark plug voltage V2 becomes a relatively small positive potential. Afterwards, both the first spark plug voltage V1 and the second spark plug voltage V2 converge towards 0 [V].

[0066] In such Figure 4 and Figure 5 In the conventional internal combustion engine ignition device 1X shown, which only has one spark plug, a large amount of residual energy remains during standby time T3. In contrast, in the internal combustion engine ignition device 1 of this embodiment, by connecting two spark plugs 91 and 92 to a secondary coil L2, the residual energy can be quickly reduced.

[0067] Furthermore, a D-DLI (Distributor Less Ignition with Double Ended Coil) system with the same circuit structure as the ignition device 1 for internal combustion engines in this embodiment is known in the past. In the D-DLI system, the first spark plug 91 and the second spark plug 92 are disposed in the combustion chambers of two cylinders with different half-cycles. That is, the second spark plug 92 is disposed in the cylinder behind the cylinder in which the first spark plug 91 is disposed.

[0068] Therefore, if the first spark plug 91 discharges near the top dead center of the compression stroke, the second spark plug 92 discharges near the top dead center of the exhaust stroke. At this time, near the top dead center of the compression stroke, the pressure inside the combustion chamber is high, requiring a large voltage for the first spark plug 91 to discharge, resulting in a large residual energy after discharge. On the other hand, near the top dead center of the exhaust stroke, the pressure inside the combustion chamber is low, requiring a small voltage for the second spark plug 92 to discharge, resulting in a small residual energy after discharge.

[0069] Therefore, the following problem exists: after discharge, even if the residual energy between the parasitic capacitance around the first spark plug 91 and the parasitic capacitance around the second spark plug 92 is canceled out, there is still some residual energy around the first spark plug 91.

[0070] In contrast, in the ignition device 1 for internal combustion engines of this embodiment, by connecting two spark plugs 91 and 92 to a secondary coil L2, residual energy can be quickly collected.

[0071] Furthermore, in the ignition device 1 for internal combustion engines of this embodiment, both the first spark plug 91 and the second spark plug 92 are disposed in the same combustion chamber. Therefore, discharge is generated simultaneously at both locations within the combustion chamber at the same time. Thus, even when multiple fuels with different ignition ease and combustion speed are mixed, ignition can be achieved more reliably. Consequently, it is possible to use mixed fuels containing hydrogen, which is more flammable than conventional fuels, and ammonia, which is less flammable than conventional fuels.

[0072] <2. Second Implementation Method>

[0073] Next, the structure of the ignition device 1A for an internal combustion engine, which is a second embodiment of the present invention, will be described with reference to the accompanying drawings. Figure 3 This is a circuit diagram of the ignition device 1A for an internal combustion engine according to the second embodiment.

[0074] like Figure 3 As shown, the ignition device 1A for an internal combustion engine includes a transformer 20A, an energizing control unit 30A, a first spark plug 91A, a second spark plug 92A, a third spark plug 93A, and a fourth spark plug 94A. The energizing control unit 30A is the same as the energizing control unit 30 in the first embodiment, so its description is omitted.

[0075] Transformer 20A has an electromagnetically coupled primary coil L1A, a first-stage coil L2A, and a second-stage coil L3A. The number of turns in both the first-stage coil L2A and the second-stage coil L3A is greater than the number of turns in the primary coil L1A. The first-stage coil L2A has a first high-voltage side terminal 21A and a first low-voltage side terminal 22A at its two ends. The second-stage coil L3A has a second high-voltage side terminal 23A and a second low-voltage side terminal 24A at its two ends.

[0076] The first spark plug 91A, the second spark plug 92A, the third spark plug 93A, and the fourth spark plug 94A are disposed inside the combustion chamber of an internal combustion engine and are devices used to achieve ignition within the combustion chamber. The first spark plug 91A has the same spark plug specifications and spark plug gap as the second spark plug 92A. Similarly, the third spark plug 93A has the same spark plug specifications and spark plug gap as the fourth spark plug 94A. The first spark plug 91A, the second spark plug 92A, the third spark plug 93A, and the fourth spark plug 94A are arranged alternately within a combustion chamber.

[0077] The first spark plug 91A is electrically connected between the first high-voltage side terminal 21A of the primary coil L2A of the transformer 20A and ground. That is, one end of the first spark plug 91A is connected to the first high-voltage side terminal 21A, and the other end of the first spark plug 91A is grounded.

[0078] The second spark plug 92A is electrically connected between the first low-voltage side terminal 22A of the primary winding L2A of the transformer 20A and ground. That is, one end of the second spark plug 92A is connected to the first low-voltage side terminal 22A, and the other end of the second spark plug 92A is grounded.

[0079] The third spark plug 93A is electrically connected between the second high-voltage side terminal 23A of the secondary coil L3A of the transformer 20A and ground. That is, one end of the third spark plug 93A is connected to the second high-voltage side terminal 23A, and the other end of the third spark plug 93A is grounded.

[0080] The fourth spark plug 94A is electrically connected between the second low-voltage side terminal 24A of the secondary winding L3A of the transformer 20A and ground. That is, one end of the fourth spark plug 94A is connected to the second low-voltage side terminal 24A, and the other end of the fourth spark plug 94A is grounded.

[0081] When the ignition switch 33 is turned on according to the ignition signal from the ECU 32, a voltage is applied to the two ends of the primary coil L1A, thereby generating a current in the primary side circuit. This creates a magnetic flux within the transformer 20A. Subsequently, when the ignition switch 33 is turned off according to the ignition signal from the ECU 32, electromagnetic induction generated by the magnetic flux created in the transformer 20A induces a high voltage at both ends of the first primary coil L2A and the second primary coil L3A, in the opposite direction to the voltage supplied by the battery 31. Consequently, the first high-voltage side terminal 21A becomes larger and negatively potentialed relative to the first low-voltage side terminal 22A, and the second high-voltage side terminal 23A becomes larger and negatively potentialed relative to the second low-voltage side terminal 24A.

[0082] As a result, the first high-voltage side terminal 21A connected to the first spark plug 91A becomes a negative potential with a large absolute value, and the first low-voltage side terminal 22A connected to the second spark plug 92A becomes a positive potential with a large absolute value. Therefore, a discharge occurs at the gap between the first spark plug 91A and the second spark plug 92A, thereby generating a spark. Thus, the fuel filled in the internal combustion engine is ignited.

[0083] Simultaneously, the second high-voltage side terminal 23A connected to the third spark plug 93A becomes a negative potential with a large absolute value, and the second low-voltage side terminal 24A connected to the fourth spark plug 94A becomes a positive potential with a large absolute value. Therefore, a discharge occurs at the gap between the third spark plug 93A and the fourth spark plug 94A, thereby generating a spark. This ignites the fuel in the internal combustion engine.

[0084] In such an internal combustion engine ignition device 1A, when the discharge period T2 ends and the standby period T3 begins, the charge moves in such a way that the charge stored in the capacitive component around the first spark plug 91A cancels out the charge stored in the capacitive component around the second spark plug 92A. As a result, the residual energy stored in the parasitic capacitance around the first spark plug 91A and the residual energy stored in the parasitic capacitance around the second spark plug 92A are both dissipated.

[0085] Furthermore, when the discharge period T2 ends and the standby period T3 begins, the charge moves in a manner that cancels out the charge stored in the capacitive component around the third spark plug 93A and the charge stored in the capacitive component around the fourth spark plug 94A. As a result, the residual energy stored in the parasitic capacitance around the third spark plug 93A and the residual energy stored in the parasitic capacitance around the fourth spark plug 94A are both dissipated.

[0086] Here, as described above, the spark plug specifications and spark plug gap of the first spark plug 91A are the same as those of the second spark plug 92A. Therefore, the residual energy stored in the parasitic capacitance around the first spark plug 91A is approximately equal to the residual energy stored in the parasitic capacitance around the second spark plug 92A. Thus, the residual energy of both is well balanced and canceled out.

[0087] Furthermore, the spark plug specifications and spark plug gap of the third spark plug 93A are the same as those of the fourth spark plug 94A. Therefore, the residual energy stored in the parasitic capacitance around the third spark plug 93A is approximately equal to the residual energy stored in the parasitic capacitance around the fourth spark plug 94A. Thus, the residual energy of both is well balanced and canceled out.

[0088] Through this movement of charge, most of the residual energy accumulated in the parasitic capacitances around each of the four spark plugs 91A, 92A, 93A, and 94A is immediately eliminated after the discharge period T2 ends, leaving very little remaining. That is, in the ignition device 1A for internal combustion engines of this embodiment, two spark plugs 91A and 92A are connected to one primary stage coil L2A, and two spark plugs 93A and 94A are connected to one secondary stage coil L3A. Thus, regardless of which spark plug 91A, 92A, 93A, or 94A is used, the residual energy can be quickly reduced.

[0089] In the ignition device 1A for internal combustion engines of this embodiment, more spark plugs 91A, 92A, 93A, and 94A are arranged in the same combustion chamber compared to the ignition device 1 for internal combustion engines of the first embodiment. As a result, the number of discharge points, i.e., heat-generating points, increases.

[0090] As a result, ignition in the combustion chamber becomes easier. Therefore, even when mixing various fuels with different ignition ease and combustion speed, reliable ignition is further ensured. Consequently, blended fuels containing hydrogen (which is more flammable than conventional fuels) and ammonia (which is less flammable than conventional fuels) can be used. In particular, even when the mixture ratio is biased towards heavier fuels depending on the location within the combustion chamber, reliable ignition is still possible with blended fuels. Furthermore, the increased number of heat-generating components accelerates the combustion rate within the combustion chamber.

[0091] <3. Variations>

[0092] The above describes exemplary embodiments of the present invention, but the present invention is not limited to the embodiments described above.

[0093] The ignition device for internal combustion engines 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. Any device that is used to generate an electric spark from the spark plug of an internal combustion engine to ignite fuel is acceptable.

[0094] The shape and structure of the detailed parts of the ignition device for internal combustion engines described above can also be appropriately modified without departing from the spirit of the invention. Furthermore, the elements appearing in the above embodiments and modifications can be appropriately combined without causing contradictions.

[0095] Explanation of reference numerals in the attached figures

[0096] 1, 1A: Ignition device for internal combustion engine; 20, 20A: Transformer; 21: High-voltage side terminal; 22: Low-voltage side terminal; 21A: First high-voltage side terminal; 22A: First low-voltage side terminal; 23A: Second high-voltage side terminal; 24A: Second low-voltage side terminal; 30: Power-on control unit; 91, 91A: First spark plug; 92, 92A: Second spark plug; 93A: Third spark plug; 94A: Fourth spark plug; L1, L1A: Primary coil; L2: Secondary coil; L2A: First primary coil; L3A: Secondary secondary coil.

Claims

1. An ignition device for an internal combustion engine, comprising: A transformer, which has a primary coil and a secondary coil that are electromagnetically coupled; A power-on control unit that controls the energization of the primary coil; The first spark plug is electrically connected between the high-voltage side terminal at one end of the secondary coil and ground; and The second spark plug is electrically connected between the low-voltage side terminal at the other end of the secondary coil and ground. in, The first spark plug and the second spark plug are disposed in the same combustion chamber of the internal combustion engine. The transformer, the first spark plug, and the second spark plug are individually matched to the combustion chamber of each of the internal combustion engines. The circuit consisting of the first spark plug, the second spark plug, and the secondary coil does not include any element that prevents the flow of current in the opposite direction to the discharge of the first spark plug and the second spark plug.

2. The ignition device for an internal combustion engine according to claim 1, wherein, The fuel gas introduced into the combustion chamber is a mixture of multiple fuels.

3. The ignition device for an internal combustion engine according to claim 2, wherein, The fuel gas introduced into the combustion chamber contains hydrogen.

4. The ignition device for an internal combustion engine according to claim 2 or 3, wherein, The fuel gas introduced into the combustion chamber contains a non-flammable fuel.

5. The ignition device for an internal combustion engine according to claim 4, wherein, The flame-retardant fuel is ammonia.

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