JPH0835473A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To not only provide an ignition plug cap on the side of the combustion chamber of a cylinder head, but also restrain the deterioration of ignition function resulting from the fluctuation of a gap due to electrode wear. CONSTITUTION:Intake valves 121 and 122 are rotatably supported on a cylinder head 3. A valve seat 22 is insulated with an annular insulator 23 and the stem 24 of the intake valve 122 is insulated with an insulator 25. Also, positive voltage is applied to the poppet section of the intake valve 122 via a plug cap wire laid on the side wall of a cylinder head and a valve seat 22, and the poppet section functions as a center electrode. The other intake valve 121 functions as a grounding electrode to cause electrical discharge. In this case, the valves 121 and 122 freely rotate. Thus, a gap fluctuation due to electrode wear is small and the deterioration of ignition function can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine ignition device, and more particularly to an internal combustion engine ignition device in which an ignition plug cap can be installed on the side of a cylinder head.

[0002]

2. Description of the Related Art In a conventional internal combustion engine, a spark plug is
It is generally screwed into a screw hole formed in the cylinder head immediately above the center of each cylinder. In this case, a relatively large mounting space is required in the cylinder head so that the spark plug can be mounted by the tightening tool.

However, in a lean-burn internal combustion engine which has been put into practical use in recent years, a plurality of engine valves are installed and a camshaft is installed above the internal combustion engine, so that it is difficult to secure a large mounting space for the cylinder head. It has become to. In order to solve the above-mentioned problems, a spark plug mounting structure has been proposed which is characterized by a spark plug mounting hole that is opened in a side wall surface of a combustion chamber of a cylinder head and a spark plug that is screwed into the hole from the combustion chamber side. (See Japanese Utility Model Laid-Open No. 62-162366).

[0004]

However, since the electrodes of the spark plug used in the mounting structure according to the above proposal are fixed, deterioration of the ignitability due to fluctuations in the distance between the electrodes due to consumption cannot be avoided. The present invention has been made in view of the above problems, and not only can the spark plug cap be provided on the side surface of the combustion chamber of the cylinder head, but also it is possible to suppress the deterioration of the ignition performance due to the fluctuation of the gap due to the consumption of the electrode. It is an object of the present invention to provide a simple internal combustion engine ignition device.

[0005]

An ignition device for an internal combustion engine according to a first aspect of the present invention is an internal combustion engine having a plurality of engine valves rotatably supported by a cylinder head. Of at least one engine valve is used as the center electrode. An ignition device for an internal combustion engine according to a second aspect of the present invention is an internal combustion engine including a plurality of engine valves rotatably supported with respect to a cylinder head, the center of which is screwed into a screw hole formed in the cylinder head. An electrode is provided and at least one engine valve of the plurality of engine valves is used as a ground electrode.

[0006]

In the ignition device for the internal combustion engine according to the first aspect of the invention, at least one engine valve rotatably supported by the cylinder head is used as the center electrode. As the engine valve rotates, the ignition location of the engine valve moves without being fixed.
In the ignition device for the internal combustion engine according to the second aspect of the invention, the center electrode is screwed to the cylinder head, and at least one engine valve rotatably supported by the cylinder head is used as the ground electrode.

[0007]

1 is a perspective view of one cylinder of a double overhead camshaft internal combustion engine to which an ignition device according to the present invention is applied, in which two intake valves 121, 122 and two exhaust valves are provided directly above a piston 11. Valves 131, 132 are arranged. The intake valves 121 and 122 are the intake valve lifter 14
The intake valve cams 161 and 162 are driven by the intake valve cams 161 and 162 via 1, 142, and the intake valve cams 161 and 162 are rotated by the intake valve shaft 18.

Similarly, the exhaust valves 131 and 132 are driven by the exhaust valve cams 171 and 172 via the exhaust valve lifters 151 and 152, and the exhaust valve cams 171 and 172 are rotated by the exhaust valve shaft 19.

1. First Embodiment FIG. 2 is a sectional view taken along the section line XX of FIG. 1, and FIG. 3 is a sectional view taken along the section line AA of FIG.
1 is used as a ground electrode, and the second intake valve 122 is used as a center electrode. The first intake valve 121 is the first stem guide 2
The second intake valve 121 is rotatably supported by the cylinder head 3 via the second stem guide 212.

In order to prevent erosion of the intake valve due to the intake air flow, the intake valve cams 161 and 162 are usually arranged so as to be offset from the centers of the intake valve lifters 141 and 142 and contact each other. Valves 121, 1
22 is forcibly rotated (this also applies to FIG. 4 described later). The exhaust valves 131 and 132 are similarly forcedly rotated.

An annular insulator 23 is fitted inside the valve seat 22 of the second intake valve 122 to ensure insulation between the conductive valve seat 22 and the cylinder head 3. An insulating portion 25 is also provided in the middle of the stem 24 of the second intake valve 122.
The insulation between the umbrella portion 22 and the cylinder head 3 is ensured.

The cylinder head 3 has a through hole 31 from the side.
The through hole 31 has a cylindrical insulating material 32.
Is inserted. A conductor 33 is arranged in the cylindrical insulating material 32, and the valve seat 22 and the conductor 33 are electrically connected. Further, the conductive wire 33 is electrically connected to the plug cap 4 installed on the side surface of the cylinder head 3.

Therefore, at the end of the compression stroke, by applying a positive voltage to the second intake valve 122 and a negative voltage to the cylinder head 3 via the plug cap 4, the conductor 33 and the valve seat 22, the first intake valve 121 is applied. And the second intake valve 1
It is possible to discharge between 22 and 22. In the compression stroke, the intake valves 121 and 122 and the exhaust valves 131 and 132
Since both are closed, ignition does not occur.

In the above-described first embodiment, the discharge is performed between the first intake valve 121 and the second intake valve 122, but the first exhaust valve 131 and the second exhaust valve 132 are discharged. It is also possible to adopt a structure in which electric discharge occurs between them.

2. Second and Third Embodiments In the first embodiment described above, it is necessary to provide the insulating portion 25 in the middle of the stem 24 of the second intake valve, but there is a difficulty in manufacturing. The second and third embodiments solve the above problems. FIG. 4 is a sectional view taken along the line XX of the second embodiment. Instead of providing the insulating portion 25 in the middle of the cylindrical stem 24, the second stem guide 212, the second valve lifter 142, and the second intake air are provided. The second shim 26 and the second cotter 27, which are arranged between the valve 122 and the stem 24, are both made of an insulating material.

Here, the intake cam 162 is the valve lifter 1.
It is offset and in contact with the center of 42. Although the intake cam 162 can be expected to rotate even if the offset contact is not made, the intake cam 162 can be positively rotated by offsetting as in the present embodiment. The three parts of the stem guide 212, the shim 26, and the cotter 27 ensure the insulation between the second intake valve 122 and the cylinder head 3.

FIG. 5 is a sectional view taken along line XX of the third embodiment, which aims at reducing the number of parts for insulation. That is, by spraying the ceramic on the upper half of the stem of the second intake valve 122 to form the insulating layer 28,
The insulation between the intake valve and the cylinder head 3 is secured.

It is also possible to use an exhaust valve for the second and third embodiments.

3. Fourth Embodiment In the first to third embodiments, the second intake valve 122 is the center electrode and the first intake valve 121 is the ground electrode, but in the fourth embodiment the first intake valve is used. Both 121 and the second intake valve 122 are used as center electrodes. 6 is a sectional view taken along the line X-X in FIG. 1, and FIG. 7 is A in FIG.
FIG. 8 is a cross-sectional view taken along the line A of FIG.

That is, for the first intake valve 121 as well, any one of the insulation methods between the second intake valve 122 and the cylinder head 3 described in the first to third embodiments is applied. The first intake valve 121 and the cylinder head 3
Ensure insulation between and. Note that FIG. 6 uses the insulating method shown in the first embodiment. In the fourth embodiment,
Electric discharge is generated between the head portion of the first intake valve 121 and the second intake valve 122 and the cylinder head 3, but the ground electrodes 341 and 342 are embedded in the cylinder head 3 in order to secure an appropriate gap. Be done.

In this embodiment, the first and second
The plug cap 4 and the electric wire 33 for supplying a positive voltage to the intake valves 121 and 122 of the first intake valve 121.
And the second intake valve 122.

4. Fifth Embodiment According to the fourth embodiment, the first and second intake valves 12
Since the electric discharge is generated between the cylinder heads 1 and 122 and the cylinder head 3, the ignition position may be the end of the cylinder, and the flame may not propagate smoothly. The fifth embodiment solves this problem, and aims to bring the ignition position closer to the center of the cylinder by performing discharge between at least one pair of intake valve and exhaust valve.

FIG. 9 is a sectional view taken along the line Y--Y of FIG. 1, and FIG. 10 is a top view showing a portion between the first intake valve 121 and the first exhaust valve 131 and a second intake valve. Electric discharge is generated between the valve 122 and the second exhaust valve 132. With respect to the first and second intake valves 121 and 122, any one of the insulation methods between the intake valve and the cylinder block described in the first to third embodiments is applied to Ensure insulation between cylinder block.

In the embodiment shown in FIGS. 9 and 10, the insulation method shown in the first embodiment is used for the first and second intake valves 121 and 122. In this embodiment, in order to keep the discharge gap constant, it is necessary to process the ends of the intake valve and the exhaust valve, which are the discharge positions, so that the ends of the umbrella parts are parallel to each other (partially enlarged view of FIG. 9). reference).

5. Sixth and Seventh Embodiments In the first to fifth embodiments, since at least one engine valve of the engine valves (intake valve and exhaust valve) is used as the center electrode, the engine valve and the cylinder block are not connected. It is necessary to maintain insulation between them, and it is unavoidable that the structure becomes complicated.

In the sixth and seventh embodiments, in order to solve the above problems, the center electrode is arranged in the cylinder head and the engine valve is used as the ground electrode, so that insulation of the engine valve is unnecessary. 11 to 13 show a sixth embodiment, FIG. 11 is a sectional view taken along the line XX of FIG. 1, FIG. 12 is a sectional view taken along the line AA of FIG.
3 is a top view.

That is, the first intake valve 121 and the second intake valve 1
A center electrode 35, whose periphery is covered with an insulator, is screwed from the inner surface of the cylinder to the cylinder head 3 located between the two. The center electrode 35 is connected to the plug cap 4 arranged on the side wall of the cylinder head 3 by the electric wire 33 covered with the insulator 32. 14 and 15 show a seventh embodiment and FIG.
4 is a sectional view taken along the line Y-Y of FIG. 1, and FIG. 15 is a top view.

That is, the first intake valve 121 and the first exhaust valve 1
The center electrodes 351 and 352, which are covered with an insulating material from the inner surface of the cylinder, are screwed to the cylinder head 3 between the first intake valve 122 and the second intake valve 122 and the second exhaust valve 132. The center electrodes 351 and 352 are the plug cap 4 and the insulator 32 arranged on the side wall of the cylinder head 3.
And are connected by electric wires 33 which are covered with and are arranged in a T shape.

6. According to the ignition device according to the first and second aspects of the present invention, since it is possible to remove the ignition plug that has been arranged directly above the cylinder of the cylinder head, it is possible to remove a plurality of intake air in a double overhead camshaft internal combustion engine. The degree of freedom in designing the diameters or arrangement positions of the valves and intake valves increases.

Further, if the ignition device according to the present invention is adopted in an internal combustion engine in which fuel is directly injected into a cylinder, the fuel injection valve is arranged in the center of the upper part of the cylinder, so that the amount of fuel adhering to the wall surface is reduced and fuel efficiency is improved. Alternatively, the property of exhaust gas can be improved. Further, in the conventional internal combustion engine that injects fuel into the intake port, the thick portion for supporting the spark plug, which has been conventionally required, can be used as the water jacket, so that the cooling effect of the internal combustion engine can be improved. Not only that, but also the cylinder head can be manufactured economically.

Further, by setting the ignition position on the anti-thrust side of the piston, it becomes possible to suppress the friction and noise between the piston and the bore.

[0032]

According to the ignition device for the internal combustion engine of the first aspect of the present invention, at least one engine valve rotatably supported by the cylinder head is used as the center electrode, thereby extending the life of the electrode. Is possible. In the ignition device for an internal combustion engine according to the second aspect of the present invention, the center electrode is screwed to the cylinder head, and at least one engine valve rotatably supported by the cylinder head is used as the ground electrode, whereby Not only can the life of the device be extended, but also the configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a perspective view of one cylinder.

FIG. 2 is a sectional view taken along line XX of the first embodiment.

FIG. 3 is a sectional view taken along line YY of the first embodiment.

FIG. 4 is a sectional view taken along line XX of the second embodiment.

FIG. 5 is a sectional view taken along line XX of the third embodiment.

FIG. 6 is a sectional view taken along line XX of the fourth embodiment.

FIG. 7 is a sectional view taken along line YY of the fourth embodiment.

FIG. 8 is a top view of the fourth embodiment.

FIG. 9 is a sectional view taken along line XX of the fifth embodiment.

FIG. 10 is a top view of the fifth embodiment.

FIG. 11 is a sectional view taken along line XX of the sixth embodiment.

FIG. 12 is a sectional view taken along line AA of the sixth embodiment.

FIG. 13 is a top view of the sixth embodiment.

FIG. 14 is a sectional view taken along line YY of the seventh embodiment.

FIG. 15 is a top view of the seventh embodiment.

[Explanation of symbols]

 121, 122 ... Intake valves 131, 132 ... Exhaust valves 211, 212 ... Stem guide 22 ... Valve seat 23 ... Insulator 3 ... Cylinder block 4 ... Plug cap

Claims (2)

[Claims] 1. An ignition system for an internal combustion engine comprising a plurality of engine valves rotatably supported by a cylinder head, wherein at least one engine valve of the plurality of engine valves is used as a center electrode. apparatus. 2. An internal combustion engine having a plurality of engine valves rotatably supported with respect to a cylinder head, comprising a center electrode screwed into a screw hole formed in the cylinder head, Ignition device for an internal combustion engine, wherein at least one engine valve of the above engine valves is used as a ground electrode.