JP2013053562A - High-frequency ignition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that distortion occurs in current of the reverse direction of a diode when the current of frequency that is half-cycle longer than a reverse recovery time is caused to flow in such a configuration that the diode for back flow prevention is provided on an ignition device, wherein the reverse recovery time is defined as a time for discharging charges to be necessarily discharged before the diode blocks the reverse current when being switched from the conduction state to the shielding state.SOLUTION: A capacitor for protection which passes AC current from a high frequency ignition coil and does not pass DC current from the ignition coil is disposed on the winding starting side or/and the winding ending side of a secondary coil of a high-frequency ignition coil. Therein, in a switching element for high-frequency, the frequency of an ignition signal is set to be 100 kHz or less and, in the capacitor for protection, the breakdown voltage is set to be 30 kV or more.

Description

The present invention relates to an ignition device using high frequency in an ignition device for an internal combustion engine.

Conventionally, in order to improve the fuel efficiency of an internal combustion engine, it is necessary to perform combustion under severe ignition conditions such as a lean air-fuel mixture, and in order to perform stable ignition under such conditions, conventional ignition is required. In addition, an ignition device is known which prevents ignition failure by adding high-frequency ignition. However, if the voltage of the high frequency ignition coil is applied to the ignition coil or the voltage of the ignition coil is applied to the high frequency ignition coil, the desired output may not be satisfied. If voltage enters, electromagnetic interference may occur. In order to solve such a problem, when a high voltage for spark discharge is generated in the ignition coil, the insulation holding means holds the high-frequency ignition coil in a substantially insulated state, so that a high voltage for spark ignition is obtained. As a typical example, for example, Japanese Patent Application Laid-Open No. 2011-099410 (hereinafter “Patent Document 1”) is known.

FIG. 6 is a block diagram showing the configuration of the ignition device disclosed in Patent Document 1. In FIG. 6, an ignition device 104 is electrically connected to a spark plug 101 having a center electrode 102 and a ground electrode 103. The ignition device 104 includes an igniter 105, an ignition coil 106, a mixer 107, an electric field generation circuit 108, and a first diode 109 and a second diode 110 that are insulation protection means. Further, the igniter 105 receives an ignition timing signal output from an electronic control device (not shown) for controlling the operation of the engine, and outputs an ignition pulse signal to the ignition coil 106.

The ignition coil 106 includes a primary winding and a secondary winding, and generates a negative high-voltage pulse voltage in the secondary winding by an ignition pulse signal from the igniter 105. Further, the igniter 105 and the ignition coil 106 may have structures well known in the art.

The mixer 107 is connected to the secondary winding of the ignition coil 106 and is connected to the first diode 109, and transmits the high-voltage pulse voltage of the ignition coil 106 to the center electrode 102 of the ignition plug 101, and the electric field. The pulsating flow obtained by rectifying the high-voltage alternating current output from the generation circuit 108 is transmitted to the center electrode 102. Further, the electric field generating circuit 108 is a circuit that converts the low-voltage direct current into the high-voltage alternating current using the battery 111 as a power source, and boosts the voltage of the battery 111, for example, about 12V (volt) to, for example, about 300V to 500V. 112, an H bridge circuit 113 that converts the direct current output from the DC-DC converter 112 into alternating current, and a step-up transformer 114 that boosts the alternating current output from the H bridge circuit 113 to a higher voltage.

The H bridge circuit 113 changes the direct current to an alternating current having a frequency of about 200 kHz to 500 MHz, preferably 100 MHz. Further, the step-up transformer 114 boosts the output of the DC-DC converter 112 to about 3 kVp-p to 10 kVp-p with a winding ratio of the primary side winding to the secondary side winding of, for example, 1:10.

The first diode 109 has its cathode connected to the signal line 115 of the secondary winding of the step-up transformer 114, that is, the end of the secondary winding not connected to the ground line 116, and its anode connected to the mixer. Connected to 107. That is, when a negative high voltage pulse voltage for spark discharge is generated in the ignition coil 106, the first diode 109 is connected to the signal line 115 so as to be opposite to the direction of the current due to the negative high voltage pulse voltage. Connected to. The reverse breakdown voltage of the first diode 109 is set to a voltage exceeding the negative high voltage pulse voltage.

In this way, when ignition is performed, that is, when a negative high voltage pulse voltage for spark discharge is generated in the ignition coil 106, a current due to the negative high voltage pulse voltage is generated from the ignition coil 106 via the mixer 107. The first diode 109 is connected to the signal line 119 of the ignition coil 106 in a direction opposite to the direction of the current due to the negative high voltage pulse voltage. The ignition coil 106 is kept electrically insulated. Similarly, the second diode 110 prevents the current due to the negative high voltage pulse voltage from flowing to the electric field generation circuit 108 via the ground 117 when a spark discharge occurs in the spark plug 101, thereby causing the ground 117. Similarly, an ignition device has also been proposed in which the electric field generation circuit 108 is electrically insulated from the ignition coil 106 on the side.

JP 2011-099410 A

However, the above conventional ignition device has the following problems. That is, in the ignition device disclosed in Patent Document 1, when a current generated by spark discharge flows to the secondary winding of the step-up transformer of the electric field generation circuit, the current is amplified by the step-up transformer, thereby causing electromagnetic interference. However, the first diode and the second diode can block the current from entering the electric field generation circuit. By preventing electromagnetic interference in this way, it is possible to prevent the operation of the electronic control device that controls the engine and the operations of various electromagnetic sensors mounted on the engine from becoming unstable. When a diode switches from a conductive state to a cut-off state, the time for the diode to discharge the charge that needs to be discharged before blocking the reverse current is called the reverse recovery time, and the half cycle is longer than this reverse recovery time. When a current having a frequency of, for example, 100 kHz or less flows, distortion occurs in the current in the reverse direction of the diode.

The present invention has been made in view of the above problems, and in an ignition device for assisting ignition of continuous discharge of a high-frequency ignition coil to discharge of a conventional ignition coil, stable operation is performed in a wide frequency range from a low frequency to a high frequency. It is an object of the present invention to provide an ignition device for an internal combustion engine using a high-frequency ignition coil capable of

In order to solve the above problems, the present invention is configured as follows. That is, in the invention of claim 1, an ignition coil composed of a primary coil and a secondary coil, an iron core, and an ignition switching element; A high-frequency ignition coil configured, wherein the switching element for ignition supplies an ignition signal to the ignition coil, the switching element for high-frequency ignition supplies an ignition signal to the high-frequency ignition coil, and the ignition coil and the high-frequency ignition In the internal combustion engine ignition device that outputs a coil to a common ignition plug provided in the cylinder, a protective capacitor is provided on the winding start side and / or winding end side of the secondary coil of the high-frequency ignition coil. The internal combustion engine ignition device is characterized.

In the above configuration, the high-frequency switching element may have an ignition signal frequency of 100 kHz or less, and the protective capacitor may have a withstand voltage of 30 kV or more.

As described above, in the ignition device for assisting ignition of the continuous discharge of the high-frequency ignition coil to the discharge of the conventional ignition coil, the protective capacitor is provided on the winding start side and / or the winding end side of the secondary coil of the high-frequency ignition coil. Ignition for internal combustion engines using a high-frequency ignition coil that can perform stable operation over a wide frequency range from a low frequency to a high frequency without selecting a frequency that takes reverse recovery time into account, such as a rectifier such as a diode A device can be realized.

In addition, since the protective capacitor passes only alternating current without passing direct current, the discharge current of the high-frequency ignition coil that is alternating current passes, and the discharge current of the conventional ignition coil that is direct current does not enter the high-frequency ignition coil. Therefore, it is possible to prevent the output failure of the ignition coil and the electromagnetic interference of the high frequency ignition coil, which are generated when a high voltage from the ignition coil is applied to the secondary coil of the high frequency ignition coil. Furthermore, the high-frequency switching element of the ignition device for an internal combustion engine according to the present invention can obtain a particular effect by setting the frequency of the ignition signal to 100 kHz or less.

1 is a circuit diagram showing a configuration of an internal combustion engine ignition device according to a first embodiment of the present invention. FIG. It is a perspective view of the ignition device for internal combustion engines. (A) is the discharge current waveform according to the first embodiment of the high-frequency ignition coil at point A in FIG. 1, and (A) is the discharge current waveform at the time of occurrence of distortion of the conventional high-frequency ignition coil at point A in FIG. is there. It is a circuit diagram which shows the structure of the ignition device for internal combustion engines which is the 2nd Example of this invention. (C) is a discharge current waveform according to the second embodiment of the high frequency ignition coil at point B in FIG. 4, and (d) is a discharge current waveform at the time of occurrence of distortion of the conventional high frequency ignition coil at point B in FIG. is there. It is a block diagram which shows the structure of the ignition device of patent document 1. FIG.

An example showing the embodiment of the present invention will be described below with reference to FIGS.

1 is a circuit diagram showing a configuration of an internal combustion engine ignition device according to a first embodiment of the present invention, FIG. 2 is a perspective view of the internal combustion engine ignition device, and FIG. FIG. 3 shows the discharge current waveform when the distortion of the conventional high-frequency ignition coil occurs at point A in FIG. 1, respectively.

1 and 2, the ignition device 90 has an ignition coil 70 and a high-frequency ignition coil 80 connected in parallel. The ignition primary coil 10a of the ignition coil 70 and the high-frequency primary coil of the high-frequency ignition coil 80 are connected to each other. The low voltage side of 10b is connected to the positive side of a common battery (not shown). The high voltage side of the primary coil 10a of the ignition coil 70 is connected to the collector of the ignition switching element 20, and the high voltage side of the primary coil 10b of the high frequency ignition coil 80 is connected to the collector of the high frequency switching element 22. It is connected. Further, the emitters of the ignition switching element 20 and the high-frequency switching element 22 are connected to the ground 52.

The base of the ignition switching element 20 is connected to the first ECU 60a, and the base of the high frequency switching element 22 is connected to the second ECU 60b. Further, the first ECU 60a is connected to the second ECU 60b.

Further, the high voltage side of the high frequency secondary coil 12b of the high frequency ignition coil 80 is provided with a protective capacitor 30a having a withstand voltage of 30 kV which prevents a direct current from the ignition coil 70 from flowing through an alternating current from the high frequency ignition coil 80. Connected to one end, the other end of the protective capacitor 30a and the high voltage side of the ignition secondary coil 12a of the ignition coil 70 are combined together and connected to a spark plug 50 provided in the cylinder. Further, the low-voltage side of the secondary coil 12b of the high-frequency ignition coil 80 is a protective capacitor 30b having a withstand voltage of 30 kV that prevents direct current from the ignition coil 70 from flowing into the high-frequency ignition coil 80 via the ground 52. The other end of the protective capacitor 30b and the low voltage side of the secondary coil 12a of the ignition coil 70 are connected to the ground 52.

Further, the case 40 forming the outer shape of the ignition device 90 is formed in a box shape with a resin as a material and having an opening surface. The coil housing portion of the case 40 is formed by laminating a plurality of thin plates. The ignition iron core 14a, the primary coil 10a in which the primary winding is wound about 100 turns around the outer periphery of the primary bobbin formed of resin on the outer periphery of the iron core 14a, and the outer periphery of the primary coil 10a A high-frequency iron formed by laminating the ignition coil 70 and a plurality of thin plates composed of the secondary coil 12a in which a secondary winding is wound about 15000 turns around the outer periphery of a secondary bobbin formed of resin. The core 14b, the primary coil 10b in which the primary winding is wound about 10 turns around the outer periphery of the primary bobbin formed of resin on the outer periphery of the iron core 14b, and the outer periphery of the primary coil 10b with resin 500 turns of secondary winding on the outer periphery of the molded secondary bobbin The HF ignition coil 80, which is composed of a degree wrapping said secondary coil 12b is housed.

The case 40 includes the ignition switching element 20 that supplies an ignition signal to the ignition coil 70 and the high-frequency switching element 22 that supplies an ignition signal to the high-frequency ignition coil 80. Further, the case 40 is provided with two case fixing portions 42 for attaching and fixing the ignition device 90 to an engine head (not shown) at two locations, that is, an opening surface of the case 40 and a substantially vertical surface.

A high voltage tower 44 for providing a high voltage terminal for supplying a secondary voltage to the spark plug 50 is formed on the bottom surface of the case 40 so as to protrude into a plug hole formed in the engine head. The high-voltage terminal receives a secondary voltage from the ignition coil 70 and the high-frequency ignition coil 80. Further, on the side surface of the case 40, a connector 46 for inputting a power supply voltage from the battery and an ignition signal from the first ECU 60a or the second ECU 60b to the ignition coil 70 and the high-frequency ignition coil 80. Are individually provided for the ignition coil 70 and the high-frequency ignition coil 80, respectively.

Further, in the case 40, electrical insulation and physical fixation of the ignition coil 70 and the high-frequency ignition coil 80, the ignition switching element 20, the high-frequency switching element 22, and the protective capacitors 30a and 30b are realized. Mold resin for filling is filled. Further, a protector for connecting the high-voltage tower 44 and the spark plug 50 is provided in the plug hole, and a secondary voltage output from the ignition coil 70 and the high-frequency ignition coil 80 is supplied from the high-voltage terminal to the protector. The spark plug 50 is supplied to the spark plug 50 through a conductive member housed in the spark plug.

From the above configuration, a series of operations of the ignition device 90 is such that when an ignition signal from the first ECU 60a to the ignition switching element 20 is turned on, a primary current is supplied to the primary coil 10a of the ignition coil 70. Simultaneously with the flow of Ia, the ignition signal from the second ECU 60b to the high-frequency switching element 22 is turned on, and the primary current Ib flows through the primary coil 10b of the high-frequency ignition coil 80. When the primary current Ia flowing through the primary coil 10a of the ignition coil 70 reaches the cutoff current value, the ignition signal from the first ECU 60a to the ignition switching element 20 is switched off, and the ignition coil The primary current Ia flowing through the primary coil 10a of 70 is cut off. Further, when the primary current Ia flowing through the primary coil 10a of the ignition coil 70 is cut off, a secondary current is generated in the secondary coil 12a of the ignition coil 70, and a secondary voltage of 30 kV is discharged. The

When the ignition signal from the second ECU 60b to the high frequency switching element 22 is switched off, the primary current Ib flowing through the primary coil 10b of the high frequency ignition coil 80 is cut off. Further, when the primary current Ib flowing through the primary coil 10b of the high-frequency ignition coil 80 is cut off, a secondary current is generated in the secondary coil 12b of the high-frequency ignition coil 80, and a secondary voltage of 5 kV is generated. Discharged.

The ignition signal from the second ECU 60b to the high-frequency switching element 22 has a frequency of 100 kHz, and the on / off of the ignition signal from the second ECU 60b to the high-frequency switching element 22 is 100 kHz. By switching the frequency, the secondary voltage of 5 kV is discharged to the spark plug 50 a plurality of times.

Next, in FIG. 3, the discharge current waveform according to the first embodiment of the high-frequency ignition coil 80 at point A in FIG. 1 is changed from the second ECU 60b to the high-frequency ignition coil as shown in FIG. The ignition signal to 80 is alternately turned on and off, thereby forming a triangular wave in which an alternating current continuously flows. Further, the discharge current waveform at the time of occurrence of distortion of the conventional high-frequency ignition coil at point A in FIG. 1 indicates that the ignition signal from the second ECU 60b to the high-frequency ignition coil 80 is on, as shown in FIG. A reverse current prevention diode that prevents a reverse flow of a large current from the ignition coil 70 provided on the high-voltage side of the secondary coil 12b of the high-frequency ignition coil 80 by a continuous alternating current flowing by alternately repeating OFF. In the case of an alternating current having a frequency whose half cycle is longer than the recovery time, the reverse current waveform is a waveform including the distortion indicated by the broken-line circle.

With the above configuration, the protective capacitors 30a and 30b do not pass a direct current through an alternating current, so that the alternating current from the high voltage side of the secondary coil 12b of the high-frequency ignition coil 80 passes through the protective capacitor 30a. Therefore, the direct current from the high voltage side of the secondary coil 12a of the ignition coil 70 also surely flows to the spark plug 50. The alternating current from the low-voltage side of the secondary coil 12b of the high-frequency ignition coil 80 flows through the protective capacitor 30b to the ground 52, and from the low-voltage side of the secondary coil 12a of the ignition coil 70. The DC current also flows to the ground 52 without fail. Thereby, since the direct current of the ignition coil 70 can prevent the high-frequency ignition coil 80 from entering the secondary coil 12b, the high voltage of the ignition coil 70 causes the secondary voltage of the high-frequency ignition coil 80 to It is possible to prevent the output failure of the ignition coil 70 and the electromagnetic interference of the high-frequency ignition coil 80 that are generated by adding to the coil 12b.

Further, since the protective capacitors 30a and 30b do not have a reverse recovery time like a rectifying element such as a backflow prevention diode, a reverse current as shown in the waveform of FIG. No distortion occurs. Accordingly, stable operation can be performed even with a current having a frequency shorter than the reverse recovery time.

As a modification of the first embodiment, the number of windings wound around the primary coils 10a and 10b and the secondary coils 12a and 12b of the ignition coil 70 and the high-frequency ignition coil 80 is the ignition device 90. The high frequency iron core 14b of the high frequency ignition coil 80 may be formed of a ferrite material. The protective capacitors 30a and 30b may be provided on either the winding start side or the winding end side of the secondary coil 12b of the high-frequency ignition coil 80. Furthermore, although the frequency of the ignition signal to the high-frequency ignition coil 80 is 100 kHz, it may be changed to an arbitrary frequency depending on design matters, or may be a frequency of 100 kHz or less.

Further, the withstand voltage of the protective capacitors 30a and 30b may be changed to a withstand voltage within a range in which the protective capacitors 30a and 30b do not fail depending on the magnitude of the secondary voltage of the ignition coil 70 and the high-frequency ignition coil 80. Further, the protective capacitors 30a and 30b are provided in the case 40 in which the ignition coil 70 and the high-frequency ignition coil 80 are accommodated. However, the ignition coil 70 and the high-frequency ignition coil 80 are accommodated in individual cases. The protective capacitors 30a and 30b may be provided in a case in which the high-frequency ignition coil 80 is accommodated, and the protective capacitors 30a and 30b may be arranged at any position as long as the surrounding insulating state can be maintained. You may arrange.

The ignition device 90 includes the ignition switching element 20 for supplying an ignition signal to the ignition coil 70 in the case 40 and the high-frequency switching element 22 for supplying an ignition signal to the high-frequency ignition coil 80. However, the ignition switching element 20 and / or the high-frequency switching element 22 may be provided outside the case 40. Further, the ignition device 90 is turned on when the ignition signal from the ignition switching element 20 to the ignition coil 70 is turned on and the ignition signal from the high frequency switching element 22 to the high frequency ignition coil 80 is turned on. Although the timing is performed at the same time, depending on the design circumstances, for example, the ignition device 90 is connected to the high-frequency ignition coil 80 from the high-frequency switching element 22 after the ignition signal from the ignition switching element 20 to the ignition coil 70 is switched off. The timing of turning on the ignition signal can be appropriately changed.

Further, the low voltage side of the primary coil 10b of the high frequency ignition coil 80 may be set to an arbitrary voltage boosted by, for example, a DC / DC converter.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, common not shown on the low voltage side of the primary coil 10a for ignition of the ignition coil 70 and the primary coil 10b for high frequency of the high frequency ignition coil 80 described in the first embodiment is common. Except for the point that the positive side of the battery is connected and the point that the collector of the high-frequency switching element 22 is connected to the high-voltage side of the primary coil 10b of the high-frequency ignition coil 80, Since this is the same as the first embodiment, the description thereof is omitted.

FIG. 4 is a circuit diagram showing the configuration of an internal combustion engine ignition device according to a second embodiment of the present invention, and FIG. 4C shows a discharge current waveform according to the second embodiment of the high-frequency ignition coil at point B in FIG. FIGS. 5A and 5B show the discharge current waveform at the time of occurrence of distortion of the conventional high-frequency ignition coil at point B in FIG.

4 and 5, the ignition device 90 has an ignition coil 70 and a high-frequency ignition coil 80 connected in parallel, and the low voltage side of the ignition primary coil 10a of the ignition coil 70 is connected to the positive side of a battery (not shown). Has been. The low-frequency side of the high-frequency primary coil 10b of the high-frequency ignition coil 80 is connected to a half-bridge circuit 56 that converts a direct current into an alternating current. The half-bridge circuit 56 is a DC / DC that boosts the power supply voltage from the battery. It is connected to the DC converter 54. Further, the high voltage side of the primary coil 10 a of the ignition coil 70 is connected to the collector of the ignition switching element 20, and the high voltage side of the primary coil 10 b of the high frequency ignition coil 80 and the emitter of the ignition switching element 20. Is connected to the ground 52.

The base of the ignition switching element 20 is connected to the first ECU 60a, and the half bridge circuit 56 is connected to the second ECU 60b. Further, the first ECU 60a is connected to the second ECU 60b.

Further, the high voltage side of the high frequency secondary coil 12b of the high frequency ignition coil 80 is provided with a protective capacitor 30a having a withstand voltage of 30 kV which prevents a direct current from the ignition coil 70 from flowing through an alternating current from the high frequency ignition coil 80. Connected to one end, the other end of the protective capacitor 30a and the high voltage side of the ignition secondary coil 12a of the ignition coil 70 are combined together and connected to a spark plug 50 provided in the cylinder. Further, the low-voltage side of the secondary coil 12b of the high-frequency ignition coil 80 is a protective capacitor 30b having a withstand voltage of 30 kV that prevents direct current from the ignition coil 70 from flowing into the high-frequency ignition coil 80 via the ground 52. The other end of the protective capacitor 30b and the low voltage side of the secondary coil 12a of the ignition coil 70 are connected to the ground 52.

From the above configuration, a series of operations of the ignition device 90 is such that when an ignition signal from the first ECU 60a to the ignition switching element 20 is turned on, a primary current is supplied to the primary coil 10a of the ignition coil 70. Ia flows. When the primary current Ia flowing through the primary coil 10a of the ignition coil 70 reaches the cutoff current value, the ignition signal from the first ECU 60a to the ignition switching element 20 is switched off, and the ignition coil The primary current Ia flowing through the primary coil 10a of 70 is cut off. Further, when the primary current Ia flowing through the primary coil 10a of the ignition coil 70 is cut off, a secondary current is generated in the secondary coil 12a of the ignition coil 70, and a secondary voltage of 30 kV is discharged. The

When the operation signal from the second ECU 60b to the half bridge circuit 56 is turned on, the half bridge circuit 56 converts the DC voltage from the DC / DC converter 54 into an AC voltage, and the high frequency ignition. A primary AC current Ib flows in the primary coil 10b of the coil 80, a secondary AC current is generated in the secondary coil 12b of the high-frequency ignition coil 80, and a secondary AC voltage of 5 kV is discharged. Further, the operation signal from the second ECU 60b to the half bridge circuit 56 has a frequency of 100 kHz, and a secondary voltage of 5 kV is discharged to the spark plug 50 a plurality of times.

Next, in FIG. 5, the discharge current waveform according to the second embodiment of the high-frequency ignition coil 80 at the point B in FIG. 4 is changed from the second ECU 60b to the half bridge circuit as shown in FIG. When the operation signal to 56 is turned on, a sinusoidal alternating current waveform flows. The discharge current waveform at the time of occurrence of distortion of the conventional high-frequency ignition coil at point B in FIG. 4 indicates that the operation signal from the second ECU 60b to the high-frequency ignition coil 80 is on, as shown in FIG. The AC current that flows when the high-frequency ignition coil 80 is turned on has a half cycle longer than the reverse recovery time of the backflow prevention diode that prevents the backflow of a large current from the ignition coil 70 provided on the high voltage side of the secondary coil 12b of the high-frequency ignition coil 80. In the case of an alternating current having a frequency, a reverse current waveform is a waveform including distortion indicated by a broken-line circle.

With the above configuration, the protective capacitors 30a and 30b do not pass a direct current through an alternating current, so that the alternating current from the high voltage side of the secondary coil 12b of the high-frequency ignition coil 80 passes through the protective capacitor 30a. Therefore, the direct current from the high voltage side of the secondary coil 12a of the ignition coil 70 also surely flows to the spark plug 50. The alternating current from the low-voltage side of the secondary coil 12b of the high-frequency ignition coil 80 flows through the protective capacitor 30b to the ground 52, and from the low-voltage side of the secondary coil 12a of the ignition coil 70. The DC current also flows to the ground 52 without fail. Thereby, since the direct current of the ignition coil 70 can prevent the high-frequency ignition coil 80 from entering the secondary coil 12b, the high voltage of the ignition coil 70 causes the secondary voltage of the high-frequency ignition coil 80 to It is possible to prevent the output failure of the ignition coil 70 and the electromagnetic interference of the high-frequency ignition coil 80 that are generated by adding to the coil 12b.

Further, since the protective capacitors 30a and 30b do not have a reverse recovery time like a rectifying element such as a backflow prevention diode, a reverse current as shown in the waveform of FIG. No distortion occurs. Accordingly, stable operation can be performed even with a current having a frequency shorter than the reverse recovery time.

As a modification of the second embodiment, the circuit configurations of the DC / DC converter 54 and the half bridge circuit 56 connected to the high-frequency ignition coil 80 may be changed to an arbitrary configuration depending on design circumstances. Instead of the half bridge circuit 56, a full bridge circuit may be used. The protective capacitors 30a and 30b may be provided on either the winding start side or the winding end side of the secondary coil 12b of the high-frequency ignition coil 80. Furthermore, although the frequency of the operation signal to the high frequency ignition coil 80 is 100 kHz, it may be changed to an arbitrary frequency depending on design matters, or may be a frequency of 100 kHz or less.

Further, the withstand voltage of the protective capacitors 30a and 30b may be changed to a withstand voltage within a range in which the protective capacitors 30a and 30b do not fail depending on the magnitude of the secondary voltage of the ignition coil 70 and the high-frequency ignition coil 80. Further, the ignition device 90 has a timing at which an ignition signal from the ignition switching element 20 to the ignition coil 70 is turned on and a timing at which an operation signal from the half bridge circuit 56 to the high-frequency ignition coil 80 is turned on. However, depending on the design circumstances, for example, the ignition device 90 may switch from the half-bridge circuit 56 to the high-frequency ignition coil 80 after the ignition signal from the ignition switching element 20 to the ignition coil 70 is switched off. The timing can be appropriately changed such as when the operation signal is turned on.

10a, 10b: Primary coil
12a, 12b: Secondary coil
14a, 14b: Iron core
20: Switching element for ignition
22: Switching element for high frequency
30a, 30b: Protection capacitors
40: Case
42: Case fixing part
44: High-pressure tower
46: Connector
50: Spark plug
52: Ground
54: DC / DC converter
56: Half-bridge circuit
60a: First ECU
60b: Second ECU
70: Ignition coil
80: High-frequency ignition coil
90: Ignition device

Claims (3)

The primary coil 10a, the secondary coil 12a, the iron core 14a, the ignition coil 70 composed of the ignition switching element 20, the primary coil 10b, the secondary coil 12b, the iron core 14b, and the high frequency ignition switching element 22 With high frequency ignition coil 80,
The ignition switching element 20 supplies an ignition signal to the ignition coil 70,
The high-frequency ignition switching element 22 supplies an ignition signal to the high-frequency ignition coil 80,
In the ignition device 90 for an internal combustion engine, the ignition coil 70 and the high-frequency ignition coil 80 output to a common ignition plug 50 provided in a cylinder.
An internal combustion engine ignition device 90 comprising protective capacitors 30a and 30b on the winding start side and / or winding end side of the secondary coil 12b of the high-frequency ignition coil 80. 2. The internal combustion engine ignition device 90 according to claim 1, wherein the high-frequency switching element 22 sets the frequency of an ignition signal to 100 kHz or less. 3. The internal combustion engine ignition device 90 according to claim 1, wherein the protective capacitors 30a and 30b have a withstand voltage of 30 kV or more.

Images