JPH0823334B2 - Ignition device for spark ignition engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition device in which a method for connecting a spark plug and a plug cap in a spark ignition engine is improved.

[Prior Art] A spark plug is externally fitted with a plug cap containing a high-voltage terminal connected to the terminal, and a high voltage generated in an ignition coil is applied. A conventional support structure for a plug cap in an engine with an engine cover which is a spark ignition engine will be described with reference to FIG.

A spark plug P is fastened to an engine E having an engine cover EC, and the spark plug P and a spark coil (not shown) are connected by a high-voltage wire HC. A plug cap PC provided at the end of the electric wire was externally fitted to the ignition plug P, and a high voltage terminal HE included in the cap PC was externally strongly fitted to the terminal PE of the ignition plug P. Further, a rubber bush RB that covers the hole of the engine cover EC and prevents the forced air cooling from leaking to the outside is fitted on the plug cap PC.

[Problems to be Solved by the Invention] However, in the conventional engine ignition device having the above-described configuration, engine vibration is directly transmitted to the plug cap. Therefore, when the ignition coil is directly connected to the plug cap, the spark plug is used. There was a problem that a load was applied to the high voltage terminal of No. 1 and a problem occurred in the spark plug, and the direct connection coil fell off from the spark plug.

The present invention can prevent the vibration of the engine or the like from being directly transmitted to the ignition coil, and even when using a direct connection coil directly connected to the ignition plug, an excessive load is applied to the high voltage terminal of the ignition plug, An object of the present invention is to provide an ignition device for a spark ignition engine, which can prevent the direct-coupling coil from falling out of an ignition plug.

[Means for Solving the Problems] In order to achieve the above object, an ignition device of a spark ignition engine of the present invention is mounted on a spark ignition engine, and a spark plug having a high-voltage terminal protruding from a rear end thereof, and the spark ignition. An engine-side member that is arranged in the vicinity of an engine and has an insertion portion that penetrates the spark plug and forms an annular gap between the spark plug and the outer periphery of the spark plug; and ignition that applies a high voltage to the spark plug inside. A tubular portion that accommodates the coil and is provided so as to cover the periphery of the high-voltage terminal of the ignition plug, and a high-voltage terminal that is provided in the tubular portion and that is elastically connected to the high-voltage terminal of the ignition plug are provided. A plug cap for directly connecting the ignition coil to the ignition plug; and a tubular cap formed so as to cover at least a rear end portion of the ignition plug and a tip end portion of the plug cap. A cylindrical body portion fitted to the outer periphery of the cylindrical portion of the plug cap on the end side, a substantially annular leg portion fitted to the inner periphery of the insertion portion of the engine side member on the other end side, and an inner periphery. A technical means including a rubber-made fixing member having an annular supporting portion that comes into contact with the outer periphery of the spark plug is adopted.

The high voltage terminal of the plug cap may be electrically connected to the high voltage terminal of the spark plug via a spring. Further, an inner peripheral groove may be provided on the body of the fixing member to lock the bulging portion formed on the outer periphery of the tubular portion. Further, the leg portion of the fixing member may be provided with an outer peripheral groove that engages with the insertion portion at two locations inside and outside. Further, the ignition coil may be fixed in the axial direction of the ignition plug.

[Operations and Effects of the Invention] The ignition device for a spark ignition engine of the present invention has the following operations and effects by the above means.

According to the ignition device of the spark ignition engine of the present invention, since the ignition coil embedded in the plug cap is fixed to the spark plug or the mounting member via the fixing member, the spark is generated during the operation of the spark ignition engine. Even if the vibration of the ignition engine is transmitted to the spark plug, the vibration of the spark plug is attenuated by the elastic connection (for example, spring), so an excessive load is transmitted from the high voltage terminal of the spark plug to the high voltage terminal of the plug cap. There is no such thing. Further, even if the vibration of the spark ignition engine or the like is transmitted to the mounting member, since the vibration of the mounting member is attenuated by the rubber fixing member, an excessive load is not transmitted from the mounting member to the plug cap.

On the other hand, even if the weight of the plug cap is increased by adopting the direct connection coil that directly connects the ignition coil to the ignition plug, the plug cap is firmly fixed to the mounting member by the fixing member, so that the plug cap is ignited. There is no risk of falling out of the plug or fixing member.
The electrical connection between the high voltage terminal of the spark plug and the high voltage terminal of the plug cap is mechanically loose.

Therefore, even if the weight of the plug cap is increased by adopting the direct connection coil that directly connects the ignition coil to the ignition plug, the large vibration generated in the spark ignition engine or the like is not directly transmitted to the ignition coil, and the ignition coil is not directly transmitted. Since it is possible to prevent the ignition coil from falling out of the ignition plug, it is possible to reliably support the ignition coil housed in the plug cap on the engine side member while isolating the vibration.
Since the electrical connection between the high-voltage terminal of the spark plug and the high-voltage terminal of the plug cap is an elastic connection, an excessive load is not applied to the spark plug, especially the high-voltage terminal of the spark plug. The problem of can be avoided.

Further, in the case where the ignition coil is connected in the axial direction of the ignition plug, it is possible to reliably support the ignition coil in the axial direction of the ignition plug while achieving vibration isolation.

[Embodiment] FIGS. 1 and 2 show an ignition device of a spark ignition engine according to the present invention.
An explanation will be given based on one embodiment shown in the drawing.

FIG. 1 shows a main part of a two-cycle gasoline engine for a two-wheeled vehicle to which an ignition device for a spark ignition engine of the present invention is applied.

Reference numeral 1 denotes an ignition device for a two-cycle gasoline engine (hereinafter abbreviated as engine) 2 for a motorcycle, which is a spark ignition engine according to the present invention, and includes an ignition plug 3, a plug cap 4, a fixing member 5, and a power supply line 11. .

The engine 2 includes a cylinder head 21, a cylinder block 22, a piston 23, and a combustion chamber 24. The cylinder head 21 located at the head of the engine 2 is formed with a spark plug mounting screw hole 26 for mounting the spark plug 3. The engine 2 is an air-cooled engine, as shown in FIG. 1, and is provided with an engine cover 25 in order to facilitate the flow of the forced air-cooling cooling air to the head.

The engine cover 25 is an engine side member of the present invention,
It is a mounting member that supports and fixes the ignition coil 6 to the engine 2 and the ignition plug 3 by mounting the ignition coil 6 via the plug cap 4 and the fixing member 5. The engine cover 25 is arranged so as to cover the head of the engine 2 and has a spark plug insertion hole 27 at the site where the spark plug 3 is mounted. The ignition plug insertion hole 27 is an insertion portion through which the ignition plug 3 penetrates, and forms an annular gap with the outer periphery of the insulator 31 of the ignition plug 3.

The spark plug 3 includes an insulator 31, a high-voltage terminal 33 protruding from a rear end 32 of the insulator 31, a fitting 34, a center electrode 35, and an outer electrode 36. The spark plug 3 has an engine cover 25.
It is fastened to a spark plug mounting screw hole 26 formed in the cylinder head 21 through a spark plug insertion hole 27 provided in the cylinder.

The plug cap 4, which is connected to the spark plug 3, is made of resin and has a primary coil 61, a secondary coil 62, and an iron core 63, which is a ferromagnetic material, inside, as shown in FIG. The ignition coil 6 is embedded. The ignition coil 6 constitutes a direct coupling coil which is directly connected to the ignition plug 3, and the plug cap 4 constitutes an ignition coil waterproof (insulating) case which covers the direct coupling coil (ignition coil 6).

At the tip (lower end in the figure) of the plug cap 4, a tubular portion 42 having a brim-shaped bulging portion 41 provided on the outer circumference is provided with an ignition coil 6.
Is extended so as to cover the outer periphery of the high-voltage terminal 33 of the spark plug 3 rather than the buried portion. A tubular metal high-voltage terminal 43 is coaxially fixed in the tubular portion 42, and the high-voltage terminal 43 is
A coiled coil spring 45 held by support members 46 and 47 is held therein.

The fixing member 5 is made of rubber, covers the ignition plug insertion hole 27 of the engine cover 25, leaks cooling air of forced air cooling to the outside, and water gets into the periphery of the ignition plug 3 through the ignition plug insertion hole 27. It is a waterproof sealing member that prevents the occurrence of abrasion. The fixing member 5 covers the ignition coil 6 (direct coupling coil) embedded in the plug cap 4 in the engine cover.
It is a mounting member for fixing the ignition plug 3 at the mounting position of 25 and a damping member for damping (absorbing) the vibration of the engine 2 and the like transmitted to the ignition coil 6. As shown in FIG. 2, the fixing member 5 is composed of a skirt-shaped leg portion 51 and a tubular body portion 55 protruding obliquely upward from the leg portion 51.
The leg portion 51 is tightly fitted to the inner peripheral edge of the spark plug insertion hole 27 of the engine cover 25. On the outer periphery of the lower end of the leg portion 51, an outer peripheral groove 52 is provided around the inner peripheral edge of the ignition plug insertion hole 27 so as to be fixed at two inner and outer locations. The body 55 is tightly fitted to the outer periphery of the tubular portion 42 of the plug cap 4. An inner circumferential groove 56 into which the brim-shaped bulging portion 41 of the plug cap 4 is fitted is provided on the inner circumference of the body portion 55. A fitting hole for tightly fitting the outer periphery of the insulator 31 of the spark plug 3 to support the spark plug 3 between the leg portion 51 and the body portion 55.
An annular support wall 54 as a support portion having 53 is provided. Further, a chamfer 57 is provided on the outer peripheral edge of the lower end of the leg portion 51.

The operation of this embodiment will be described with reference to FIGS. 1 and 2.

In the fixing member 5 of this embodiment, the outer peripheral groove 52 has an engine cover.
25 is fitted to the edge of the ignition plug insertion hole 27 and fixed to the engine cover 25, and the tubular portion 42 of the plug cap 4 is further fitted to the body portion 55, and the brim-shaped bulging portion 41 of the tubular portion 42 is inserted. It is fitted into the inner circumferential groove 56. As a result, the plug cap 4 is fixed to the engine cover 25 via the fixing member 5. At this time, the high-voltage terminal 33 protruding from the rear end 32 of the insulator 31 of the fire plug 3 is fitted in the coiled coil spring 45. As a result, the high voltage terminal 33 of the spark plug 3 and the high voltage terminal 43 of the plug cap 4 are electrically connected to each other by using the coiled coil spring 45. The connection is mechanical and the connection is loose. Therefore, even if the weight of the plug cap 4 in which the ignition coil 6 is embedded is large, the mechanical connection between the high-voltage terminal 33 and the high-voltage terminal 43 is elastic, so that the ignition plug 3, especially the ignition plug 3 is connected.
Excessive load is not applied to the high voltage terminal 33 of.

Therefore, when the engine vibration is transmitted to the spark plug 3 during the operation of the engine 2, this vibration is absorbed by the coil spring 45, and an excessive load is prevented from being transmitted to the high voltage terminal 43 of the plug cap 4.

On the other hand, the plug cap 4 is firmly fixed by the fixing member 5, so that the plug cap 4 is simply the spark plug 3
Even when the weight of the plug cap 4 such as the direct coupling coil is larger than that of the one fitted to the high voltage terminal 33, the plug cap 4 is prevented from falling off.

In the present embodiment, the engine cover is used as the engine side member, but other members such as a cylinder and a cylinder head cover directly connected to the engine may be used as the engine side member.

The elastic contact may be made with an elastic body other than the coiled coil spring. For example, the high-voltage terminal of the spark plug may be held by the inner peripheral portion of the skirt-shaped coil spring on the small diameter side.

In this embodiment, the two-cycle gasoline engine for a two-wheeled vehicle is used as the spark ignition engine, but other spark ignition engines such as a four-cycle gasoline engine for a four-wheeled vehicle may be used. The spark plug is not limited to this embodiment, and various spark plugs can be used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an ignition device 2 for a spark ignition engine according to the present invention.
A cross-sectional view of the essential parts of a two-cycle gasoline engine for wheeled vehicles, No. 2
FIG. 1 is an enlarged cross-sectional view of a main part of FIG. 1, and FIG. 3 is a cross-sectional view of a main part of an engine showing a conventional engine ignition device. In the figure, 1 ... Ignition device, 2 ... Two-cycle gasoline engine for two-wheeled vehicle (spark ignition engine), 3 ... Spark plug, 4
...... Plug cap, 5 ...... Fixing member, 6 ...... Ignition coil, 21 ...... Cylinder head, 25 ...... Engine cover (engine side member), 27 ...... Ignition plug insertion hole (insertion part),
31 ... Insulator, 33 ... High-voltage terminal, 41 ... Collar-shaped bulge,
42 …… Cylindrical part, 43 …… High voltage terminal, 45 …… Collective coil spring, 51 …… Leg part, 52 …… Outer groove, 53 …… Mating hole, 54 …… Support wall (support part ), 55 …… Body, 56 …… Inner circumferential groove, 61 …… Primary coil, 62 …… Secondary coil, 63 …… Iron core

Claims (5)

[Claims] 1. A spark plug which is mounted on a spark ignition engine and has a high-voltage terminal projecting from a rear end thereof. (B) A spark plug which is arranged in the vicinity of the spark ignition engine and which penetrates the spark plug and at the same time. An engine side member having an insertion portion in which an annular gap is formed between the ignition coil and an outer periphery of the ignition plug, and (c) an ignition coil for applying a high voltage to the ignition plug is housed inside, and a periphery of a high voltage terminal of the ignition plug And a high-voltage terminal that is provided inside the tubular portion and that is elastically connected to the high-voltage terminal of the ignition plug, and that connects the ignition coil directly to the ignition plug. A plug cap, and (d) is formed in a tubular shape so as to cover at least the rear end portion of the ignition plug and the tip end portion of the plug cap, and is fitted to the outer periphery of the tubular portion of the plug cap at one end side. A rubber having a tubular body portion, a substantially annular leg portion fitted to the inner periphery of the insertion portion of the engine side member on the other end side, and an annular support portion contacting the outer periphery of the spark plug on the inner periphery. Ignition device for a spark ignition engine including a fixing member made of metal. 2. The spark ignition engine according to claim 1, wherein the high voltage terminal of the plug cap is electrically connected to the high voltage terminal of the spark plug via a spring. Ignition device. 3. The body portion of the fixing member has an inner peripheral groove for locking a bulging portion formed on the outer periphery of the tubular portion, according to claim 1 or 2. Ignition device of the spark ignition engine according to the item. 4. The leg portion of the fixing member has an outer peripheral groove that engages with the insertion portion at two locations inside and outside, and any one of claims 1 to 3 inclusive. Spark ignition engine ignition device. 5. The ignition device for a spark ignition engine according to claim 1, wherein the ignition coil is fixed in an axial direction of the ignition plug.