JPH08167532A - Ignition coil for internal combustion engine - Google Patents

Abstract

PURPOSE: To provide an ignition coil for an internal combustion engine which is easily manufactured in a small size while maintaining predetermined ignition performance by forming a suitable core structure for a simultaneous ignition ignition coil. CONSTITUTION: A magnetic path is formed of an inner core and an outer core wound with a primary coil 12 and a secondary coil 22 in parallel with two sets of ignition coils 1A, 1B, and high voltage terminals are connected to the coil 22. The inner cores 2 of the two sets of the coils 1A, 1B are coaxially disposed, and an air gap 5 of a predetermined gap is formed between the outer cores 2 of the side at least opposed with the cores 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an internal combustion engine, and more particularly to a simultaneous ignition system ignition coil for an internal combustion engine that ignites two cylinders with one ignition coil.

[0002]

2. Description of the Related Art There are various known ignition systems for internal combustion engines. Among them, in a simultaneous ignition system (also called a double ignition system) ignition coil, one cylinder is in a compression process. The two cylinders are selected so that the other cylinder is in the exhaust process, and the output high voltage is simultaneously applied to these cylinders. For example, regarding a four-cylinder internal combustion engine, the first cylinder and the fourth cylinder
In the case where the cylinders are ignited at the same time and the second cylinder and the third cylinder are ignited at the same time, for example, when the first cylinder is in the compression process, the pressure inside the cylinder is large, so that it does not easily discharge even at high voltage. Since the fourth cylinder is in the exhaust process and the pressure inside the cylinder is close to the atmospheric pressure, it easily discharges at a low voltage, and the resistance of the spark plug becomes a negligible value. Therefore, when the ignition plugs of the first cylinder and the fourth cylinder are connected in series,
The ignition plug of the fourth cylinder in the exhaust process has almost no resistance, and almost all output high voltage is applied to the first cylinder in the compression process. Therefore, it is similar to the case where a high voltage is individually applied to each spark plug by the ignition coil.

An ignition coil that realizes the simultaneous ignition method as described above is disclosed, for example, in Japanese Patent Laid-Open No. 4-226007. According to the invention proposed in the publication, plural sets of second laminated cores, primary coils, and secondary coils are housed in a single container-shaped resin housing in which plural sets of first laminated cores are embedded. Therefore, the number of man-hours and space for assembling the ignition coil to the engine and the vehicle body can be reduced. Specifically, two sets of ignition coils, each having a C-shaped laminated core and an I-shaped laminated core and having a coil wound around the latter, are arranged in parallel, and are clearly shown in FIG. 4 of the publication. As described above, the pair of I-shaped laminated cores located at the axial center of each coil are arranged in parallel.

Similarly, Japanese Examined Patent Publication No. 6-73339 includes an iron core having one main leg and at least two shunt branches magnetically connected in parallel to the main leg. And each of the shunt branches includes one upper leg and one lower leg arranged perpendicular to the main leg and one outer leg arranged parallel to the main leg. And each of the shunt branches has a void and 2
An ignition coil for an ignition device of an internal combustion engine is disclosed, which has a number of ignition plugs and is not provided with a distributor, of the type having one primary winding concentrically surrounded by a secondary winding. That is, as is apparent from FIG. 1 of the publication, the iron cores located at the respective axial centers of the two coils are arranged in parallel.

[0005]

In the two sets of ignition coils in which the two cores are arranged in parallel as described in the above publication, the core structure is restricted and it is difficult to reduce the size. Further, the wiring between the primary coils wound around each core is complicated, and even if they are separately wired to avoid this,
Processing of the lead wires outside the device becomes a problem.

However, if the cores of the two ignition coils are simply made common, focusing only on downsizing and simplification of wiring,
Two sets of ignition coils magnetically interfere with each other to ignite at the same time, and simultaneous ignition is performed in four cylinders. For this reason, some magnetic shielding means is additionally required, and the effect due to the common use of the bent cores is offset.

Therefore, the present invention provides an ignition coil for an internal combustion engine which is small in size and easy to manufacture while maintaining desired ignition performance by providing an appropriate core structure with respect to a simultaneous ignition type ignition coil. With the goal.

[0008]

In order to achieve the above-mentioned object, the present invention provides, as described in claim 1, an inner core around which a primary coil and a secondary coil are wound, and a magnetic path together with the inner core. In the ignition coil for an internal combustion engine, which has two sets of ignition coils each having an outer core forming a coil and has high-voltage terminals connected to both ends of each of the secondary coils, each inner core of each of the two sets of ignition coils is In addition to being arranged on the same axis, at least each inner core is arranged so as to form an air gap of a predetermined gap between the inner core and the outer core on the side facing each other.

Further, according to the present invention, as described in claim 2, an inner core around which the primary coil and the secondary coil are wound,
An ignition coil for an internal combustion engine having two sets of ignition coils each having an outer core forming a magnetic path together with the inner core, and having high-voltage terminals connected to both ends of each of the secondary coils. The inner cores of the coil are arranged on the same axis, and at least the inner cores are permanently opposed to each other so that the magnetic poles on the mutually opposing sides have the same polarity with the outer core. A magnet may be interposed.

In the ignition coil for an internal combustion engine, as described in claim 3, the outer cores constituting the two sets of ignition coils are integrally formed in a letter-shaped form, and the outer shape of the letter-shaped form is formed. The inner cores of the two sets of ignition coils may be arranged on the same axis in the two space portions of the core.

[0011]

In the ignition coil for an internal combustion engine of the present invention, two sets of ignition coils are arranged in parallel, and in each ignition coil, a magnetic path is formed by an inner core and an outer core wound with a primary coil and a secondary coil. A high voltage terminal is connected to both ends of each of the secondary coils. The inner cores of the two sets of ignition coils are arranged on the same axis, and in the invention according to claim 1, a predetermined gap is provided between the inner cores and the outer cores at least on the sides facing each other. Air gap is formed. Further, in the invention according to claim 2, permanent magnets are respectively interposed between the inner cores and the outer cores so that the magnetic poles on the mutually opposing sides have the same polarity. To be done. When the primary current supplied to the primary coil of each ignition coil is interrupted, the magnetic flux changes in the outer core and the inner core, and a high voltage is induced in the secondary coil of each ignition coil. Therefore, if both ends of each secondary coil are respectively connected to the ignition plug, a simultaneous ignition type ignition coil is constructed, and two ignition plugs are ignited at the same time. At this time, one ignition coil is the energizing side and the other is the non-energizing side, but since the air gap or the permanent magnet is provided as described above, the non-energizing side causes magnetic interference by the energizing side. Properly ignites without receiving.

In the ignition coil for an internal combustion engine according to a third aspect of the present invention, the outer cores forming the two sets of ignition coils are integrally formed in a letter V shape, and two outer cores are provided in two space portions. Since the inner cores of the pair of ignition coils are arranged on the same axis, the size is further reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an ignition coil for an internal combustion engine of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of an ignition coil 1 for an internal combustion engine according to the present invention, in which two sets of ignition coils 1A and 1B are integrally arranged side by side. Since both have the same structure, the same reference numerals are given to the same parts and portions, and in the following description, only one of them will be mainly described. As shown in FIG. 1, the ignition coil 1 for an internal combustion engine of the present embodiment has a letter-shaped core 3, and a pair of column-shaped cores 2 and 2 are coaxially arranged in two space portions thereof. It has the shape of. That is, the core 3 corresponds to the outer core according to the present invention, and the core 2 corresponds to the inner core according to the present invention. Each core 2 is built in the primary coil assembly 10, and the secondary coil assembly 20
When two sets are assembled, and these are housed in the two space portions of the core 3 in the case 30, the structure shown in FIGS. 1 and 2 is obtained.

The case 30 is a housing made of synthetic resin, and the core 3 is built into the case 30 by insert resin molding at a substantially central portion thereof. Therefore, Case 3 corresponds to the letter-shaped core 3.
Two space parts are formed in 0, and the primary coil assembly 10 and the secondary coil assembly 20 are accommodated therein, respectively. On one side of the side wall of the case 30, four high-voltage connector portions 31a to 31d are arranged in parallel on the same plane, and the high-voltage terminal 7 is housed in each of them.
An igniter (which controls the primary current of the primary coil and is also called an ignition module) 8 is attached to the side wall of the case 30 opposite to the high voltage connector portions 31a to 31d, and flanges are provided on the other side walls. Part 3
3 is extendedly formed.

As shown in FIG. 7, the core 3 constituting the outer core is a letter-shaped iron core and is formed by laminating a plurality of non-oriented silicon steel sheets, but a grain-oriented silicon steel sheet may be used. It is also possible to form a square V-shaped outer core for each ignition coil 1A, 1B and join them together. Core 3
All of the parts facing the core 2 are projected inward, the projection 3a is formed wide, and the projection 3b is formed narrow. As shown in FIG. 5, the portion including the protrusion 3a and the protrusion 3b and contacting the core 2 is exposed without being covered with the resin material of the case 30. On the other hand, in the core 2, both ends of the main body portion 2a are widened to extend portions 2b and 2c.
Is a columnar iron core in which the core 3 is formed in the extending portion 2c.
Is formed with a recess into which the protruding portion 3a is fitted. The core 2 of this embodiment is formed by laminating a plurality of grain-oriented silicon steel plates whose rolling direction is the axial direction of the main body 2a. Then, the cores 2 and 2 are arranged on the same axis in the two space portions of the core 3, and an air gap 5 having a predetermined gap is formed between the cores 2 and 2 on the side where the cores 2 and 2 face each other. It

FIG. 5 is an enlarged view showing one ignition coil 1A side. The primary coil assembly 10 includes a primary bobbin 11 and a holding portion 13 in which the core 2 is integrally housed by insert resin molding. ing. Primary bobbin 1
1 is formed around the main body portion 2a of the core 2, and flange portions 11a and 11b are formed at a predetermined distance from each other. The holding portion 13 formed at one end of the primary bobbin 11 in the axial direction is
As shown in FIG. 5, the air gap 5 having the above-mentioned predetermined gap is secured between the extending portion 2b of the core 2 and the protruding portion 3a of the core 3, and the end face in the longitudinal direction of the extending portion 2b is exposed. Core 3
It is formed so as to face the end surface (exposed surface) of the protruding portion 3a. Then, the collar portions 11 a, 11 of the primary bobbin 11
The primary coil 12 is wound in two or four layers between b to form the primary coil assembly 10.

On the other hand, the secondary coil assembly 20 is formed by winding a secondary coil 22 around a secondary bobbin 21. As shown in FIG. 5, the secondary bobbin 21 is a resin tubular body having a substantially rectangular cross section in which a plurality of collar portions 21a are formed at predetermined intervals in the axial direction, and a plurality of grooves 21b are provided between the collar portions 21a. The windings of the secondary coil 22 are sequentially wound in these grooves 21b from the upper side to the lower side in FIG. The both ends of the secondary bobbin 21 are wide brim portions 21c and 21d, and the terminals 23 shown in FIG. 1 are fitted in the grooves (not shown) formed in the brim portions 21c and 21d, respectively. The winding start or winding end of the secondary coil 22 is wound around each terminal 23 and electrically connected thereto. That is,
Both ends of the secondary coil 22 are connected to the terminals 23, respectively. In addition, each terminal 23 extends in a direction orthogonal to the axis of the secondary bobbin 21, and when the terminal 23 is later assembled in the case 30, the terminal 23 is inserted into the high-voltage terminal 7, and the two are electrically connected. Connected.

The high voltage terminals 31a to 3 of the case 30
An igniter 8 is mounted on the side wall opposite to 1d at a position close to between the two sets of ignition coils 1A and 1B.
The igniter 8 may be mounted by bonding or screwing, or by forming a housing portion in the case 30 and housing the igniter 8 in the housing portion 30.
The igniter 8 may be integrally provided at the time of molding. A part of the igniter 8 accommodates, for example, a circuit element indicated by a chain line in FIG. 6 (which will be described later).
terminals 6a, 6b connected to the collector side of r2,
The terminal 6e, which is a common power supply terminal, is formed to extend inside the case 30 as shown in FIG.

The primary coil assembly 10 and the secondary coil assembly 20 are housed in a case 30 as shown in FIG. 2, and each terminal 23 is inserted into each high voltage terminal 7. On the ignition coil 1A side, one end 12a of the winding of the primary coil 12 is electrically connected to the terminal 6e via the leads 6c and 6d, and the other end 12b is a notch (not shown) in the collar 11a. And is led out and electrically connected to the terminal 6a (terminal 6b on the ignition coil 1B side). In this way, the electrical connection between the primary coil 12 and the igniter 8 is provided between the two sets of ignition coils 1A and 1B, so wiring is easy. After this wiring, the space in the case 30 is filled with a thermosetting synthetic resin, for example, an epoxy resin, and is cured, so that the case shown in FIG.
The resin portion 9 is formed as shown by the dotted lines. As a result, the primary coil 12 and the secondary coil 22 are impregnated and fixed, and the electrical connection between the primary coil 12 and the igniter 8 is appropriately insulated, and further, the insulation that can withstand the high output voltage of the secondary coil 22. Sex is secured.

Thus, as shown in FIG. 3, a single ignition coil 1 for an internal combustion engine having two sets of ignition coils 1A and 1B in the case 30 is formed. The ignition coil 1 for an internal combustion engine is mounted on an internal combustion engine (not shown), and as shown in FIG. 4, the high voltage connector portions 31a to 31d are connected to the ignition plugs 81 to 84 via the high tension cords 71 to 74.
Connected to. That is, the ignition plug 81 attached to the first cylinder and the ignition plug 84 attached to the fourth cylinder are connected to the high voltage connector portions 31a and 31b of the ignition coil 1A,
The ignition plug 82 attached to the second cylinder and the ignition plug 83 attached to the third cylinder are connected to the high voltage connector portions 31c and 31d of the ignition coil 1B.

FIG. 6 shows an essential part of an ignition circuit for a four-cylinder internal combustion engine according to this embodiment. When the primary current of each primary coil 12 is interrupted by the switching transistors Tr1 and Tr2, each secondary coil 22 is connected. A back electromotive force is induced in the and a high voltage of 30 to 40 kv is generated. This high voltage is output to the spark plugs 81 to 84 via the terminal 23 and the high voltage terminal 7 of FIG. As shown in FIG. 3, the igniter 8 is provided with a connector portion 16, in which the power supply terminal 16e, the drive signal terminals 16a and 16b, the ground terminal 16c, and the monitor terminal (see FIG. 6) shown in FIG. Are omitted) are arranged in a line.

In the ignition coil for the internal combustion engine of the present embodiment having the above-mentioned structure, the ignition coil 81 of the first cylinder and the fourth coil
The ignition coil 84 of the cylinder is ignited at the same time, and the ignition coil 82 of the second cylinder and the ignition coil 83 of the third cylinder are ignited at the same time. For example, when the first cylinder is in the compression process, the pressure inside the cylinder is large, so the ignition coil 81 does not easily discharge even at a high voltage, but the fourth cylinder is in the exhaust process and the pressure inside the cylinder becomes atmospheric pressure. Since they are close to each other, they are easily discharged at a low voltage, the resistance of the ignition plug 84 becomes a negligible value, and almost all the output high voltage is applied to the ignition coil 81 of the first cylinder in the compression process. Thus, a high voltage is individually applied to the ignition plugs 81 to 84 by the ignition coils 1A and 1B, a spark discharge is generated in each electrode portion, and a compressed air-fuel mixture in each combustion chamber (not shown) is generated. Is ignited. At this time, one ignition coil (for example, 1A) is on the energizing side and the other ignition coil (1B) is on the non-energizing side, but since the air gap 5 is provided, the non-energizing side ignition coil (1
B) is not magnetically interfered by the ignition coil (1A) on the energization side, and stable ignition operation is performed.

FIG. 8 shows an experimental result confirming the effect of the air gap 5 in the above-mentioned embodiment. The solid line shows the change of the magnetic flux density of the ignition coil provided with the air gap 5, and the air gap 5 is provided. The change in the magnetic flux density when the inner core and the outer core are in close contact without each other is shown by a broken line. As is clear from the figure, the change in the magnetic flux density on the non-energized side in the latter case is interfered by the magnetic field on the energized side, and is the required value for ignition in cylinders that do not require ignition as indicated by the chain double-dashed line. The change in the magnetic flux density at a certain ignition limit is exceeded. On the other hand, in the present embodiment in which the air gap 5 is provided, the change in the magnetic flux density on the non-energized side is not affected by the magnetic field on the energized side and remains below the ignition generation limit.

FIG. 9 shows an ignition coil for an internal combustion engine according to another embodiment of the present invention. Two sets of ignition coils 1A and 1A are provided.
The outer core that constitutes B is separated into two cores 3x, 3x, which are arranged with a predetermined gap (gap which receives magnetic interference with each other, for example, 10 mm or less). That is, if one ignition coil 1A is energized as it is, the other ignition coil 1B is in a positional relationship such that it receives magnetic interference as described above. On the other hand, in this embodiment, the permanent magnet PM is interposed between the core 2 as the inner core and the core 3x as the outer core so that the magnetic poles on the opposite sides have the same pole (for example, N pole). Has been done. The permanent magnet PM has a rectangular shape, and the widths of both sides of the permanent magnet PM are respectively the extension 2 of the core 2.
It is set to a value slightly larger than the width of both sides of the cross section of b. Therefore, the cross-sectional area of the permanent magnet PM depends on the extension 2 of the core 2.
It is larger than the cross-sectional area of b, and the end portion in the longitudinal direction extends outward from the joint portion 2b of the core 2 as shown in FIG. As the permanent magnet PM, for example, samarium-cobalt (Sm-C), which has a large residual magnetic flux density and is hard to be demagnetized.
A rare earth magnet of a sintered body of o) type metal is used.

Thus, each permanent magnet PM is turned toward the adjacent cores 3x, 3x, and then each core 3 is moved.
Since the flow of magnetic flux that circulates along x, 3x is formed, the desired magnetic flux change can be obtained without interfering with the flow of magnetic flux in each core 3x, 3x. As a result, the non-energized ignition coil can properly ignite without being magnetically interfered by the energized ignition coil. Moreover, in each ignition coil 1A, 1B, a large effective magnetic flux change can be secured by the permanent magnet PM. Therefore, the magnetic flux density formed in the primary coil 12 becomes large with respect to the magnetomotive force due to the passage of the primary current, the discharge energy increases, and the change in the magnetic flux interlinking the secondary coil 22 becomes large. Coil 2
Since the output voltage of 2 becomes large, a better ignition performance can be secured.

FIG. 10 shows still another embodiment of the present invention, in which the outer cores 3x and 3x are replaced by a core 3 which is integrally formed in the shape of a letter. According to this, similarly to the embodiment shown in FIG. 2 described above, after being integrally molded in the case 30, the primary coil assembly 10 and the secondary coil assembly 20 are housed in the space, so that the manufacturing Will be easier. Also in this embodiment, the flow of magnetic flux by the permanent magnet PM is formed in the same manner as in the embodiment of FIG. 9, so that the desired magnetic flux change can be obtained on both sides of the core 3 without mutual interference of the magnetic flux flow. To be

[0027]

Since the present invention is constructed as described above, it has the following effects. That is, according to the ignition coil for an internal combustion engine of the present invention, in claim 1, the inner cores of the two sets of ignition coils are arranged on the same axis, and at least the outer cores are arranged on the opposite side to the outer side. An air gap having a predetermined gap is formed between the core and each of the cores. Further, according to claim 2, the inner cores of the two sets of ignition coils are arranged on the same axis and at least each of the inner cores is arranged. Between the inner cores facing each other and the outer cores, the permanent magnets are respectively interposed so that the magnetic poles on the mutually facing sides are the same, and two sets of ignition coils are provided. Since the electrical connection of each primary coil can be arranged in the gap between each inner core while maintaining the desired ignition performance without mutual magnetic interference, it is small, easy to manufacture, and inexpensive. Can be configured to.

Further, in the ignition coil for an internal combustion engine according to a third aspect, the outer cores forming the two sets of ignition coils are integrally formed in a letter-shaped form, and the letter-shaped outer core is formed. The two inner cores of the two ignition coils are arranged on the same axis in each of the two space portions, so that the desired ignition performance can be achieved by one outer core for the two ignition coils. It can be ensured, and it can be made smaller, easier to manufacture, and cheaper.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an ignition coil for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view of an internal combustion engine ignition coil according to an embodiment of the present invention.

FIG. 3 is a perspective view of an ignition coil for an internal combustion engine according to an embodiment of the present invention.

FIG. 4 is a perspective view showing a state in which an internal combustion engine ignition coil according to an embodiment of the present invention is connected to an ignition plug.

FIG. 5 is an enlarged sectional view of a part of an ignition coil for an internal combustion engine according to an embodiment of the present invention.

FIG. 6 is an electric circuit diagram showing a main part of an ignition coil for an internal combustion engine according to an embodiment of the present invention.

FIG. 7 is a plan view showing a configuration of a core of an internal combustion engine ignition coil according to an embodiment of the present invention.

FIG. 8 is a graph showing the experimental results for confirming the effect of the air gap in one example of the present invention.

FIG. 9 is a cross-sectional view of an ignition coil for an internal combustion engine according to another embodiment of the present invention.

FIG. 10 is a plan view showing a configuration of a core of an ignition coil for an internal combustion engine and a permanent magnet according to still another embodiment of the present invention.

[Explanation of symbols]

 1 Ignition Coil for Internal Combustion Engine 1A, 1B Ignition Coil 2 Core, 2a Main Body, 2b, 2c Extension 3,3x Core, 3a, 3b Projection 5 Air Gap 6a, 6b, 6e Terminal 7 High-voltage Terminal 9 Resin 10 Primary coil assembly 11 Primary bobbin, 11a, 11b Collar part 12 Primary coil 13 Holding part 20 Secondary coil assembly 21 Secondary bobbin, 21a Collar part, 21b groove 22 Secondary coil 23 Terminal 30 Case 31a-31d High voltage connector part 33 Flange Part PM Permanent magnet

[Procedure amendment]

[Submission date] January 27, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The high-voltage connector portions 31a to 3 of the case 30
An igniter 8 is mounted on the side wall opposite to 1d at a position close to between the two sets of ignition coils 1A and 1B.
The igniter 8 may be mounted by bonding or screwing, or by forming a housing portion in the case 30 and housing the igniter 8 in the housing portion 30.
The igniter 8 may be integrally provided at the time of molding. A part of the igniter 8 accommodates, for example, a circuit element indicated by a chain line in FIG. 6 (which will be described later).
terminals 6a, 6b connected to the collector side of r2,
The terminal 6e, which is a common power supply terminal, is formed to extend inside the case 30 as shown in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

In the ignition coil for the internal combustion engine of this embodiment having the above-mentioned structure, the ignition plug 81 and the fourth cylinder of the first cylinder are used.
The ignition plugs 84 of the cylinders are ignited at the same time, and the ignition plugs 82 of the second cylinder and the ignition plugs 83 of the third cylinder are ignited at the same time. For example, when the first cylinder is in the compression process, the internal pressure of the cylinder is large, so the spark plug 81 does not easily discharge even at a high voltage, but the fourth cylinder is in the exhaust process and the internal pressure of the cylinder becomes atmospheric pressure. Since they are close to each other, they are easily discharged at a low voltage, the resistance of the spark plug 84 becomes a negligible value, and almost all output high voltage is applied to the spark plug 81 of the first cylinder in the compression process. Thus, a high voltage is individually applied to the ignition plugs 81 to 84 by the ignition coils 1A and 1B, a spark discharge is generated in each electrode portion, and a compressed air-fuel mixture in each combustion chamber (not shown) is generated. Is ignited. At this time, one ignition coil (for example, 1A) is on the energizing side and the other ignition coil (1B) is on the non-energizing side, but since the air gap 5 is provided, the non-energizing side ignition coil (1
B) is not magnetically interfered by the ignition coil (1A) on the energization side, and stable ignition operation is performed.

Claims (3)

[Claims] 1. Two sets of ignition coils each having an inner core around which a primary coil and a secondary coil are wound, and an outer core forming a magnetic path together with the inner core are provided, and both ends of each of the secondary coils are provided. In an internal combustion engine ignition coil equipped with a connected high-voltage terminal, the internal cores of the two sets of ignition coils are arranged on the same axis, and at least the internal cores are opposed to each other on the side facing each other. An ignition coil for an internal combustion engine, wherein the ignition coils are arranged so as to form an air gap having a predetermined gap therebetween. 2. An ignition coil having two sets of an inner core around which a primary coil and a secondary coil are wound, and an outer core forming a magnetic path with the inner core, the two sets being provided at both ends of each of the secondary coils. In an internal combustion engine ignition coil equipped with a connected high-voltage terminal, the internal cores of the two sets of ignition coils are arranged on the same axis, and at least the internal cores are opposed to each other on the side facing each other. An ignition coil for an internal combustion engine, characterized in that permanent magnets are interposed between the magnetic poles so that the magnetic poles on the opposite sides are the same. 3. The outer cores forming the two sets of ignition coils are integrally formed in a letter V shape, and the two sets of ignition coils are respectively provided in two space portions of the letter-shaped outer cores. 3. The ignition coil for an internal combustion engine according to claim 1 or 2, wherein each of the internal cores is arranged on the same axis.