JP2017142953A - Multi-point ignition plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-point ignition plug which is capable of multi-point ignition in a wide range and allows easy exchange.SOLUTION: A multi-point ignition plug 100 for igniting an air-fuel mixture inside a combustion chamber 4 of an engine 1 comprises: a body part 10, having a flat shape, which is inserted into an insertion hole 5 of the engine 1 such that its tip 11 faces the combustion chamber 4; a pair of side electrodes 12 provided in a longer direction of the tip 11 with a gap formed therebetween; and at least one intermediate electrode 13 provided in the gap between the pair of side electrodes 12 so as to form a plurality of ignition gaps 14 along the longer direction of the tip 11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a multipoint spark plug having a plurality of spark gaps.

  Patent Document 1 discloses a multipoint ignition device in which a plurality of ignition gaps are formed by a plurality of intermediate members held by a head gasket interposed between a cylinder head and a cylinder block of an engine.

JP 2009-041366 A

  However, in the multipoint ignition device of Patent Document 1, when replacing the spark plug, the entire head gasket is replaced. Therefore, it is necessary to remove the cylinder head from the cylinder block.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a multipoint ignition plug that can perform multipoint ignition in a wide range and can be easily replaced.

  According to an aspect of the present invention, the multipoint spark plug for igniting the air-fuel mixture in the combustion chamber of the engine is formed in a flat shape and is inserted into the engine insertion hole so that the tip portion faces the combustion chamber , A pair of side electrodes provided with a gap in the longitudinal direction of the tip, and a plurality of ignition gaps provided in the gap between the pair of side electrodes, along the longitudinal direction of the tip And at least one intermediate electrode.

  In this aspect, since a plurality of ignition gaps are formed along the longitudinal direction at the front end portion of the main body portion formed flat, multipoint ignition in a wide range is possible. Further, the main body portion formed flat is inserted into the insertion hole of the engine so that the tip portion faces the combustion chamber. Therefore, the multipoint spark plug can be replaced by simply pulling out the multipoint spark plug from the engine insertion hole and inserting a new multipoint spark plug. Therefore, it is possible to provide a multipoint ignition plug that can perform multipoint ignition in a wide range and can be easily replaced.

FIG. 1 is a diagram illustrating a state in which a multipoint ignition plug according to an embodiment of the present invention is attached to an engine. FIG. 2A is a side view of FIG. FIG. 2B is a side view for explaining another attachment state of the multipoint spark plug to the engine. FIG. 3 is a perspective view of the multipoint spark plug. 4 is a plan view of FIG. FIG. 5 is a front view of FIG. FIG. 6 is a diagram for explaining the relationship between the side electrodes and the intermediate electrode and the insulator, and is a view showing the insulator in cross section.

  Hereinafter, a multipoint spark plug 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the engine 1 to which the multipoint ignition plug 100 is applied will be described with reference to FIGS. 1, 2A, and 2B.

  As shown in FIG. 1, an engine 1 includes a cylinder 2a formed in a cylinder block 2, a piston 2b that reciprocates in the cylinder 2a, and a cylinder head that is attached to the cylinder block 2 and closes the top of the cylinder 2a. 3 (see FIG. 2A). In the engine 1, a combustion chamber 4 is formed by a cylinder 2 a, a piston 2 b, and a cylinder head 3. The engine 1 is a spark ignition internal combustion engine that obtains power by the ignition plug 7 and the multipoint ignition plug 100 igniting and burning the air-fuel mixture compressed in the combustion chamber 4.

  The engine 1 has a pair of insertion holes 5 for inserting the multipoint spark plug 100. As shown in FIG. 2A, the insertion hole 5 is formed in the cylinder head 3. Not only this but insertion hole 5 may be formed in head gasket 6 between cylinder block 2 and cylinder head 3, as shown in Drawing 2B. Although not shown, the insertion hole 5 may be formed in the cylinder block 2.

  In the engine 1, the insertion holes 5 are formed in the combustion chamber 4 at positions away from the spark plugs 7 on the intake valve 8 side and the exhaust valve 9 side (lower end portion of the combustion chamber 4). In the engine 1, ignition is performed by the multipoint ignition plug 100 in addition to the ignition plug 7, so that a flame flow due to combustion can be generated. As a result, rapid combustion can be realized without providing a squish area, and cooling loss can be reduced.

  However, the present invention is not limited to this, and the insertion hole 5 may be formed in the combustion chamber 4 away from the spark plug 7 and at a location where the temperature of the air-fuel mixture is low, that is, where knocking is likely to occur. Moreover, the insertion hole 5 may be formed only in one place of the combustion chamber 4, and may be formed in multiple places of three or more places. Thus, by forming the insertion hole 5 according to the shape of the combustion chamber 4, an arbitrary number of multi-point spark plugs 100 can be provided.

  Next, the configuration of the multipoint spark plug 100 will be described with reference to FIGS. 3 to 6.

  As shown in FIGS. 3 and 4, the multipoint spark plug 100 includes a main body portion 10 that is formed in a flat shape and is inserted into the insertion hole 5 of the cylinder head 3 so that the front end portion 11 faces the combustion chamber 4. A pair of side electrodes 12 provided with a gap in the longitudinal direction of the portion 11 and an intermediate electrode provided in the gap between the pair of side electrodes 12 and forming a plurality of ignition gaps 14 along the longitudinal direction of the tip portion 11 13, an insulator 15 that protrudes from the tip 11 into the combustion chamber 4 and holds the side electrode 12 and the intermediate electrode 13, and is formed larger than the main body 10 and is attached to the cylinder head 3. And a flange portion 20 as an attachment portion.

  The main body 10 has a rounded rectangular cross-sectional shape corresponding to the shape of the insertion hole 5 and is formed to have a length corresponding to the insertion hole 5. The main body 10 is made of a metal such as aluminum. As shown in FIG. 4, a metal gasket 16 is wound around the main body 10 as a first seal material that closes the gap with the insertion hole 5. The metal gasket 16 will be described in detail later.

  The tip portion 11 is formed in the same shape as the inner periphery of the combustion chamber 4 and constitutes a part of the inner periphery of the combustion chamber 4. That is, the tip portion 11 is formed in a spherical shape having the same radius as the hemispherical combustion chamber 4 when the multipoint ignition plug 100 is attached to the cylinder head 3 having the hemispherical combustion chamber 4. Further, when the multi-point spark plug 100 is attached to the head gasket 6, the distal end portion 11 is formed in a curved surface shape having the same radius as the inner periphery of the cylinder 2a.

  The side electrode 12 is held by the main body 10 via the insulator 15. The side electrode 12 further protrudes from the insulator 15 into the combustion chamber 4. The side electrode 12 is formed so as to protrude from the distal end portion 11 in an L shape. One side electrode 12 extends through the main body 10 and the flange 20 to an input terminal 22 described later. Similarly, the other side electrode 12 extends through the main body portion 10 and the flange portion 20 to a connection terminal 23 described later. The pair of side electrodes 12 are provided such that their tips are opposed to each other. One side electrode 12 receives an ignition current from an ignition coil (not shown) via an input terminal 22.

  A pair of intermediate electrodes 13 is provided between a pair of opposed side electrodes 12. The intermediate electrode 13 is held by the main body 10 via the insulator 15. The intermediate electrode 13 further protrudes from the insulator 15 into the combustion chamber 4. Unlike the side electrode 12, the intermediate electrode 13 does not penetrate the main body 10 and is inserted and held in the main body 10 only partially.

  The intermediate electrode 13 is linearly arranged so as to form three ignition gaps 14 at equal intervals between a pair of opposed side electrodes 12. Thus, since the plurality of ignition gaps 14 are formed along the longitudinal direction at the front end portion 11 of the main body portion 10 formed flat, multipoint ignition in a wide range in the combustion chamber 4 is possible. is there.

  Only one intermediate electrode 13 may be provided, or three or more intermediate electrodes 13 may be provided. The number of the intermediate electrodes 13 is arbitrarily set according to the size in the longitudinal direction of the distal end portion 11 of the main body 10, the number of designed ignition gaps 14, and the like.

  The intermediate electrode 13 is formed to protrude from the tip end portion 11 in a T shape. As a result, the ignition current input from the ignition coil to one side electrode 12 can flow through the ignition gap 14 in a straight line and flow to the other side electrode 12. Therefore, it is possible to reliably generate a spark at the ignition gap 14.

  The insulator 15 insulates the side electrode 12 and the intermediate electrode 13 from the main body 10. The insulator 15 that holds the side electrode 12 is formed to have a length that partially protrudes from the distal end portion 11 and penetrates the main body portion 10 and the flange portion 20. A part of the insulator 15 that holds the intermediate electrode 13 protrudes from the tip part 11, and a part of the insulator 15 is inserted into the body part 10.

  As shown in FIG. 6, the insulator 15 is formed in a concave shape from the front end surface 15a, and a bottom surface 15b that holds the outer periphery of the side electrode 12 and the intermediate electrode 13, and the side electrode 12 and the middle from the bottom surface 15b to the front end surface 15a. A curved surface portion 15c formed in a curved shape that smoothly connects the bottom surface 15b and the tip surface 15a so as to be separated from the electrode 13; The insulator 15 is made of an insulating material such as ceramic.

  Thus, by forming the curved surface portion 15c, the path from the side electrode 12 and the intermediate electrode 13 to the outer periphery of the main body portion 10 is longer than when the bottom surface 15b is not formed in a concave shape from the front end surface 15a. Become. Therefore, it is possible to suppress the side electrode 12 and the intermediate electrode 13 from being short-circuited with the cylinder head 3 via the outer periphery of the main body 10.

  As shown in FIG. 1, the metal gasket 16 is attached to the outer periphery of the main body 10 when the main body 10 of the multipoint spark plug 100 is inserted into the insertion hole 5. Thereby, when the multipoint spark plug 100 is attached, the metal gasket 16 seals the gap between the main body 10 and the insertion hole 5. The metal gasket 16 is made of a metal material. The metal gasket 16 has a bead portion 16a protruding to the outer periphery.

  The bead portion 16a protrudes in an annular shape from the approximate center of the metal gasket 16 toward the outer periphery. By providing the bead portion 16 a, the gap between the main body portion 10 and the insertion hole 5 can be sealed without being affected by errors in the inner periphery of the insertion hole 5 and the outer periphery of the main body portion 10.

  The flange portion 20 is formed to protrude from the main body portion 10 to the outer periphery over the entire circumference of the main body portion 10. The flange portion 20 is integrally formed with the main body portion 10 by a metal such as aluminum. The flange part 20 has a pair of fastening holes 25a. The flange portion 20 is fastened to the outer surface of the cylinder head 3 by a pair of bolts 25 inserted through the fastening holes 25a. The flange portion 20 is provided with an O-ring 21 as a second sealing material that seals the contact surface with the cylinder head 3.

  The O-ring 21 is inserted into an O-ring groove 20a formed in an annular shape on the surface of the flange portion 20 facing the main body portion 10. The O-ring 21 is made of a rubber material.

  The O-ring 21 is crushed between the cylinder head 3 by the fastening force of the bolt 25. Thereby, when the flange portion 20 is fastened to the cylinder head 3, the O-ring 21 seals the gap between the main body portion 10 and the insertion hole 5.

  In the engine 1, the gap between the main body portion 10 of the multipoint spark plug 100 and the insertion hole 5 of the engine 1 is double-sealed by the metal gasket 16 and the O-ring 21. You may seal only by either one with the ring 21. FIG.

  The flange portion 20 is connected to one side electrode 12 and is connected to the input terminal 22 to which an ignition current from the ignition coil is input, and to the other side electrode 12 and is input to the other multipoint spark plug 100. And a connection terminal 23 connected to the terminal 22.

  As a result, a pair of multi-point spark plugs 100 provided in one combustion chamber 4 can be connected in series via a plug cord (not shown) and simultaneously ignited. It is also possible to perform ignition simultaneously by connecting the spark plug 7 further in series via a plug cord (not shown) at the tip of the pair of multi-point spark plugs 100. At this time, the ground electrode 7a (see FIG. 2A) of the spark plug 7 contacts the cylinder head 3 and is grounded.

  Next, replacement work of the multipoint spark plug 100 will be described.

  When exchanging the multipoint spark plug 100, first, the pair of bolts 25 are removed, and the main body 10 is pulled out from the insertion hole 5 of the engine 1. Next, the metal gasket 16 is wound around the main body 10 of the new multipoint spark plug 100, and the O-ring 21 is inserted into the O-ring groove 20 a and inserted into the insertion hole 5 of the engine 1. And if a pair of volt | bolt 25 is inserted and fastened by the fastening hole 25a, replacement | exchange of the multipoint spark plug 100 will be completed.

  In this way, the multipoint ignition plug 100 can be replaced simply by pulling out the multipoint ignition plug 100 from the insertion hole 5 of the engine 1 and inserting a new multipoint ignition plug 100. Exchange of 100 is easy.

  At this time, unlike the spark plug 7, the multi-point spark plug 100 itself is not rotated and screwed into the female screw of the cylinder head 3, so that the side electrode 12 and the intermediate electrode 13 are placed in the combustion chamber 4. It can be reliably arranged at a specified position. Therefore, even if the multipoint spark plug 100 is replaced, the position of the ignition gap 14 does not change, so that the air-fuel mixture can be burned as designed.

  According to the above embodiment, there exist the effects shown below.

  In the multipoint ignition plug 100, since the plurality of ignition gaps 14 are formed along the longitudinal direction at the distal end portion 11 of the main body portion 10 formed flat, multipoint ignition in a wide range is possible. Further, the main body portion 10 formed in a flat shape is inserted into the insertion hole 5 of the engine 1 so that the tip portion 11 faces the combustion chamber 4. Therefore, the multipoint spark plug 100 can be replaced by simply pulling out the multipoint spark plug 100 from the insertion hole 5 of the engine 1 and inserting a new multipoint spark plug 100. Therefore, it is possible to provide a multipoint ignition plug 100 that can perform multipoint ignition in a wide range and can be easily replaced.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, in the above-described embodiment, the main body portion 10 and the flange portion 20 are integrally formed of a metal such as aluminum, and the insulator 15 formed of an insulating material such as ceramic is inserted therein. Instead of this, the main body portion 10 and the insulator 15 may be integrally formed of an insulating material such as ceramic, and the flange portion 20 formed of a metal such as aluminum may be attached thereto.

DESCRIPTION OF SYMBOLS 100 Multipoint spark plug 1 Engine 2 Cylinder block 3 Cylinder head 4 Combustion chamber 5 Insertion hole 10 Main-body part 11 Tip part 12 Side electrode 13 Intermediate electrode 14 Ignition gap 15 Insulator (electrode holding part)
15a Front end surface 15b Bottom surface 15c Curved surface portion 16 Metal gasket (first seal material)
16a Bead part 20 Flange part (mounting part)
21 O-ring (second sealing material)
22 Input terminal 23 Connection terminal

Claims (5)

A multi-point spark plug for igniting an air-fuel mixture in an engine combustion chamber,
A main body portion that is formed into a flat shape and is inserted into the insertion hole of the engine such that the tip portion faces the combustion chamber;
A pair of side electrodes provided with a gap in the longitudinal direction of the tip,
A multipoint ignition plug comprising: at least one intermediate electrode provided in the gap between the pair of side electrodes and forming a plurality of ignition gaps along a longitudinal direction of the tip portion. The multipoint spark plug according to claim 1,
An electrode holder that protrudes from the tip portion into the combustion chamber and holds the side electrode and the intermediate electrode;
The multi-point spark plug according to claim 1, wherein the side electrode and the intermediate electrode further protrude from the electrode holding portion into the combustion chamber. The multi-point spark plug according to claim 2,
The multi-point spark plug characterized in that the electrode holding part insulates the side electrode and the intermediate electrode from the main body part. The multi-point spark plug according to any one of claims 1 to 3,
The multi-point spark plug according to claim 1, wherein the tip portion is formed in the same shape as the inner periphery of the combustion chamber and constitutes a part of the inner periphery. The multipoint spark plug according to any one of claims 1 to 4,
An input terminal connected to one of the side electrodes and receiving an ignition current from an ignition coil;
A multi-point spark plug, further comprising a connection terminal connected to the other side electrode and connected to the input terminal of another multi-point spark plug.

Images