CN114122915A

CN114122915A - Pre-combustion chamber spark plug assembly and engine

Info

Publication number: CN114122915A
Application number: CN202111306226.0A
Authority: CN
Inventors: 刘华龙; 琚雪明; 张振兴
Original assignee: Chery Automobile Co Ltd
Current assignee: Chery Automobile Co Ltd
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-03-01
Anticipated expiration: 2041-11-05
Also published as: CN114122915B

Abstract

The application provides a precombustion chamber spark plug assembly, this precombustion chamber spark plug assembly includes spark plug, precombustion chamber and cylinder cap, and the lower part of spark plug links to each other with the upper portion of precombustion chamber, and the lower part of precombustion chamber is installed in the cylinder cap, and the precombustion chamber includes long cylindric lower cavity, and spark plug and lower cavity intercommunication, lower cavity run through the cylinder cap. The precombustion chamber comprises a lower cavity, the outer wall of the lower cavity has a larger heat dissipation area, heat transferred to the side electrode and the central electrode can be effectively reduced, and the side electrode and the central electrode are prevented from being ablated.

Description

Pre-combustion chamber spark plug assembly and engine

Technical Field

The application relates to the technical field of engines, in particular to a pre-combustion chamber spark plug assembly and an engine.

Background

In order to improve the thermal efficiency of the engine, the related art improves the thermal efficiency of the engine through an exhaust gas recirculation technique and an increase in the compression ratio of the engine, but this increases the difficulty of engine ignition and decreases the combustion rate. In order to solve the problems of difficult ignition and reduced combustion rate, the related art reduces the ignition difficulty by arranging the precombustion chamber to perform local enrichment, increases the ignition point of a main combustion chamber by jet ignition of the precombustion chamber, and improves the combustion rate of an engine. However, in the related art, the space of the precombustion chamber is small, the arrangement space of the spark plug is severely limited, the heat dissipation effect of the precombustion chamber is poor, and the spark plug is easy to ablate due to high temperature.

Disclosure of Invention

In view of this, the present application provides a pre-chamber spark plug assembly and an engine, which have better heat dissipation effect.

Specifically, the method comprises the following technical scheme:

in one aspect, a spark plug assembly is provided, the pre-chamber spark plug assembly including a spark plug, a pre-chamber, and a cylinder head, a lower portion of the spark plug being connected to an upper portion of the pre-chamber, a lower portion of the pre-chamber being mounted within the cylinder head,

the precombustion chamber comprises a long cylindrical lower cavity, the spark plug is communicated with the lower cavity, and the lower cavity penetrates through the cylinder cover.

Optionally, the inner diameter of the lower cavity is gradually reduced from top to bottom.

Optionally, the bottom end of the precombustion chamber is provided with at least one jet hole, and the lower cavity is communicated with the main combustion chamber of the engine through the jet hole.

Optionally, an included angle between an axis of the nozzle hole and an axis of the lower cavity in a direction towards the combustion chamber ranges from 50 ° to 85 °.

Optionally, the spark plug includes a center electrode, a heat insulating member surrounding the center electrode, and a housing, the housing including a partition cavity, a side electrode disposed in the partition cavity, the center electrode extending from an end opening of the heat insulating member into the partition cavity, and the side electrode surrounding the center electrode at a spacing.

Optionally, the central electrode comprises a recess located at a lower portion of the central electrode, and the recess is surrounded by the thermal insulation.

Optionally, the heat insulation element comprises a convex portion, and the housing further comprises a limiting cavity, wherein the convex portion is located in the limiting cavity.

Optionally, the pre-chamber spark plug assembly further comprises a flat gasket located between the housing and the pre-chamber.

Optionally, the spark plug further comprises an upper gasket, a buffer sleeve and a lower gasket, wherein the upper gasket, the buffer sleeve and the lower gasket are encircled between the outer wall of the heat insulation piece and the inner wall of the limit cavity.

Optionally, the thermal insulation element is an insulating ceramic body.

In another aspect, a method of assembling a pre-chamber spark plug assembly is provided, for assembling the above-described pre-chamber spark plug assembly, comprising:

inserting the center electrode into the heat insulator from an upper end of the heat insulator;

installing the thermal shield into the housing, completing the packaging of the pre-chamber spark plug;

installing and fastening the pre-chamber spark plug in connection with the pre-chamber;

the pre-chamber spark plug assembly is installed into a cylinder head with a special tool.

In yet another aspect, an engine is provided that includes the prechamber spark plug assembly described above.

The technical scheme provided by the embodiment of the application has the beneficial effects that at least:

in the precombustion chamber spark plug assembly that this application provided, the precombustion chamber is including cavity down, and fuel steam burns in the cavity of resorption of precombustion chamber, and lower cavity is long cylindric and runs through the cylinder cap, and precombustion chamber spark plug side electrode has bigger heat radiating area, and fuel steam can effectively transmit the heat dissipation of spark plug outer wall near the burning production of spark plug, avoids the electrode of spark plug to be ablated, has increased the reliability of spark plug.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a cross-sectional view of an assembly of a pre-chamber spark plug assembly provided in accordance with an embodiment of the present application;

FIG. 2 is a cross-sectional view of a spark plug provided in accordance with an embodiment of the present application;

FIG. 3 is a schematic illustration of a spark plug assembly provided by an embodiment of the present application;

FIG. 4 is a bottom view of a spark plug assembly provided by an embodiment of the present application;

FIG. 5 is a partial cross-sectional view of a prechamber provided in accordance with embodiments of the present disclosure;

FIG. 6 is a flow chart illustrating a method of assembling a pre-chamber spark plug assembly according to an embodiment of the present disclosure.

The reference numerals in the figures are denoted respectively by:

1-a central electrode;

100-a shaped portion;

101-a recess;

102-an ellipsoid portion;

103-step surface;

104-a lower end;

2-a thermal insulation;

201-open ended;

202-a convex part;

203-a first limit surface;

3-a buffer structure;

301-upper gasket;

302-a buffer sleeve;

303-lower gasket;

4-a shell;

401-partition cavity;

402-a side electrode;

4021-sector electrode;

403-gap;

404-external housing threads;

405-a spacing cavity;

406-an opening;

407-prism;

408-a second limiting surface;

409-plain washer;

5-a spark plug;

6-precombustion chamber;

601-lower cavity;

602-a transition cavity;

603-upper cavity;

604-prechamber external threads;

605-spraying holes;

7-cylinder cover;

8-prechamber gasket;

9-buffer cushion.

With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Reference to orientation terms in the embodiments of the present application, such as "upper," "lower," "side," and the like, are generally based on the relative relationship of the orientations shown in fig. 1, and these orientation terms are used merely for clarity of description of the structures and the relationship between the structures, and are not used for describing absolute orientations. When the product is placed in different postures, the orientation may be changed, for example, "up" and "down" may be interchanged.

Unless defined otherwise, all technical terms used in the examples of the present application have the same meaning as commonly understood by one of ordinary skill in the art. Some technical terms appearing in the embodiments of the present application are explained below.

In the embodiments of the present application, reference is made to a "head" that is generally mounted to a cylinder of an engine for sealing the cylinder and forming a main combustion chamber.

In a first aspect, the present embodiment provides a pre-chamber spark plug assembly, as shown in fig. 1, the pre-chamber spark plug assembly includes a spark plug 5, a pre-chamber 6, and a cylinder head 7, a lower portion of the spark plug 5 is connected to an upper portion of the pre-chamber 6, a lower portion of the pre-chamber 6 is installed in the cylinder head 7, the pre-chamber 6 includes a long cylindrical lower cavity 601, the spark plug 5 is communicated with the lower cavity 601, and the lower cavity 601 penetrates through the cylinder head 7.

In the precombustion chamber spark plug assembly that the application provided, precombustion chamber 6 is including cavity 601 down, and fuel steam burns in cavity 601 of precombustion chamber 6 down, and cavity 601 is long cylindric and runs through cylinder cap 7 down, and precombustion chamber spark plug side electrode has bigger heat radiating area, and fuel steam burns the heat that produces near spark plug 5, can effectively transmit the outer wall heat dissipation to spark plug 5, avoids spark plug 5's electrode to be ablated, has increased spark plug's reliability.

In order to make the technical solutions and advantages of the present application clearer, the following will describe the embodiments of the present application in further detail with reference to the accompanying drawings.

As shown in fig. 1, the pre-combustion chamber spark plug assembly includes a spark plug 5, a pre-combustion chamber 6, and a cylinder head 7, wherein the spark plug 5 includes a center electrode 1, a heat insulator 2, and a housing 4, the center electrode 1 is inserted into the heat insulator 2 from the upper end of the heat insulator 2, the heat insulator 2 surrounds the center electrode 1, a lower end portion 104 of the center electrode 1 protrudes from an end opening 201 of the lower end of the heat insulator 2, a lower portion of the heat insulator 2 is mounted in the housing 4, a lower portion of the housing 4 is connected to the pre-combustion chamber 6, and a lower portion of the pre-combustion chamber 6 is mounted in the cylinder head 7 and penetrates the cylinder head 7 through a lower cavity 601. The housing 4 includes a partition chamber 401, and a side electrode 402 is provided in the partition chamber 401. A step surface 103 is provided on the upper portion of the center electrode 1, and the step surface 103 abuts against the upper end surface of the heat insulator 2 to restrict the relative position of the center electrode 1 and the heat insulator 2. The center electrode 1 protrudes from the end opening 201 of the heat insulator 2 and extends into the partition chamber 401 of the case 4. The side electrode 402 is positioned in the partition cavity 401, the inner wall of the partition cavity 401 is connected with the side electrode 402, the side electrode 402 surrounds the central electrode 1 at intervals, a gap 403 exists between the side electrode 402 and the central electrode 401, and when the central electrode 1 is electrified, electric sparks are generated between the side electrode 402 and the central electrode 1. The partition chamber 401 communicates with the lower cavity 601 of the precombustion chamber 6 through the gap 403 between the side electrode 402 and the center electrode 401.

In some embodiments of the present application, as shown in fig. 3-4, the side electrode 402 may include a plurality of fan electrodes 4021, and the plurality of fan electrodes 4021 may be connected to the housing 4 by welding or may be integrally formed with the housing 4 by a stamping process. Every two adjacent fan electrodes 4021 are spaced by the same distance, and each fan electrode 4021 is concentric with the central electrode 1 and has the same inner diameter, so that the gap 403 between each fan electrode 4021 and the central electrode 1 is uniform. For example, referring to fig. 4, the number of sector electrodes 4021 may be 3, and the central angle of each sector electrode 4021 may be 110 °. The sector electrode 4021 has a large surface area, can withstand higher temperature and has a better heat dissipation effect, thereby effectively preventing the side electrode 402 from being ablated.

In some embodiments of the present application, referring to fig. 2, the center electrode 1 may include a shaped portion 100, the shaped portion 100 being a lower portion of the center electrode 1 and surrounded by the thermal shield 2. As shown in the partial view of the profiled section 100 in fig. 2, the profiled section 100 may comprise a recess 101, the diameter of the central electrode 1 at the recess 101 being smaller than the diameter of the main part of the central electrode 1. During the operation of the engine, fuel steam is combusted in the pre-combustion chamber 6, the lower end part 104 of the central electrode 1 is heated to have higher temperature, and the special-shaped part 100 can reduce the heat transfer of the lower end part 104 of the central electrode 1 to the upper part of the central electrode 1, so that the central electrode 1 mainly radiates heat through the heat insulation piece 2.

In some embodiments of the present application, as shown in fig. 2, the shaped part 100 may further include an ellipsoid part 102, the ellipsoid part 102 is connected to the lower end of the concave part 101, the connection between the ellipsoid part 102 and the concave part 101 is a smooth rounded corner, the major axis of the cross section of the ellipsoid part 102 has a length equal to the diameter of the main body of the central electrode 1, the minor axis of the cross section of the ellipsoid part 102 has a length substantially equal to the length of the concave part 101, and the diameter of the lower end 104 of the central electrode 1 is smaller than the diameter of the main body. A first stopper surface 203 inclined downward is provided in the heat insulator 2, and when the center electrode 1 is inserted into the heat insulator 2, the lower surface of the ellipsoidal part 102 abuts against the first stopper surface 203, and the lower end 104 of the center electrode 1 is inserted into the heat insulator 2 and protrudes from the end opening 201 of the heat insulator 2. The heat insulator 2 restricts the position of the center electrode 1 in the heat insulator 2 by the first stopper surface 203.

As shown in fig. 5, prechamber 6 comprises lower cavity 601, transition cavity 602, and upper cavity 603. Wherein the upper cavity 603 is adapted to be connected to the lower portion of the housing 4. The lower cavity 601 has a smaller inner diameter than the upper cavity 603, and the transition cavity 602 is located between the upper cavity 603 and the lower cavity 601. Wherein the inner diameters of the lower cavity 601 and the transition cavity 602 may gradually decrease from top to bottom. The lower end of the transition cavity 602 is connected with the upper end of the lower cavity 601, the upper end of the lower cavity 601 has a larger inner diameter, the lower end of the lower cavity 601 has a smaller inner diameter, and the wall thickness of the lower end of the precombustion chamber 6 is gradually increased from top to bottom. The lower chamber 601 may also be of a straight cylinder type, the length of the lower chamber 601 being slightly greater than the thickness of the cylinder head 7 where the prechamber 6 is mounted. The outer wall of the partition chamber 401 is inserted into the upper chamber 603, and the central electrode 1 and the side electrode 402 are communicated with the lower chamber 601 through the transition chamber 602.

In some embodiments of the present application, referring to FIG. 5, the bottom end of the prechamber 6 is provided with at least one jet hole 605, and the lower cavity 601 communicates with the main combustion chamber of the engine through the jet hole 605. The plurality of jet holes 605 are uniformly arranged at intervals at the bottom end of the precombustion chamber 6, and the included angle between the axis of each jet hole 605 and the axis of the lower cavity 601 in the direction towards the combustion chamber ranges from 50 degrees to 85 degrees. When the spark plug is ignited, the fuel steam in the lower cavity body 605 is ignited firstly, and the flame is obliquely jetted into the engine main combustion chamber through the plurality of jet holes 605 at a plurality of angles, so that the fuel steam in the main combustion chamber is ignited, and the fuel steam in the main combustion chamber is fully combusted.

In some embodiments of the present application, as shown in fig. 2, the thermal shield 2 includes a boss 202, and the housing 4 includes a confinement chamber 405, the boss 202 being positioned within the confinement chamber 405 to limit the relative position of the thermal shield 2 and the housing 4. The upper end of the housing 4 is bendable to form a deformable opening 406, and the boss 202 is inserted into the stopper cavity 405 through the opening 406. When the pre-chamber spark plug assembly is mounted, the center electrode 1 is inserted into the heat insulator 2, the convex portion 202 of the heat insulator 2 is inserted into the housing 4, and the upper end portion of the housing 4 is bent to reduce the diameter of the opening 406 so that the diameter of the opening 406 is smaller than the diameter of the convex portion 202, thereby preventing the heat insulator 2 from being detached from the housing 4.

It will be appreciated that, as shown in figure 2, in order to limit the depth of insertion of the thermal shield 2 into the housing 4, the lower part of the housing 4 is provided with a second stop surface 408. The second limiting surface 408 is inclined downward and the diameter of the lower part of the heat insulating member 2 is gradually reduced from top to bottom, so that the outer side wall of the heat insulating member 2 is abutted to the second limiting surface 408.

In some embodiments of the present application, as shown in fig. 2, the heat insulating element 2 and the housing 4 may be provided with a cushion pad 9 at the second limiting surface 408, and the cushion pad 9 has elasticity to protect the contact surface of the heat insulating element 2 and the housing 4.

In some embodiments of the present application, as shown in fig. 2, the pre-chamber spark plug assembly may further include a buffer structure 3, and the buffer structure 3 is installed between the convex portion 202 and the upper end inner wall of the stopper cavity 405. When the upper end of the case 4 is bent, the buffer structure 3 prevents the upper end of the case 4 from directly contacting the convex portion 202, and prevents the heat insulating material 2 from being deformed by pressure. In particular, the cushioning structure 3 may include an upper gasket 301, a cushion sleeve 302, and a lower gasket 303. The upper gasket 301, the cushion collar 302 and the lower gasket 303 surround the outer wall of the heat insulating member 2 and contact the inner wall of the spacing chamber 405. Wherein, the upper gasket 301 and the lower gasket 303 have the same structure, the shape of the cross section thereof may be circular, the cross section of the cushion collar 302 may be rectangular, the upper gasket 301 and the lower gasket 303 are in contact with the rounded surfaces forming the opening 406 and the protrusion 202, respectively, and the cushion collar 302 is disposed between the upper gasket 301 and the lower gasket 303 to prevent the outer wall of the heat insulating member 2 from being in direct contact with the inner wall of the case 4.

It will be appreciated that, as shown in fig. 2, for connecting the housing 4 and the prechamber 6, the outer surface of the lower part of the housing 4 may be provided with a housing external thread 404 and the upper cavity 603 of the prechamber 6 with a matching internal thread (see fig. 1), so that the lower part of the housing 4 fits into the upper cavity 603 of the prechamber 6.

In some embodiments of the present application, as shown in fig. 2-4, the outer wall of the housing 4 at the limiting cavity 405 is formed with a prism 407, and the cross section of the prism 407 may be a regular hexagon, so that the prism 407 can be fixed by a tool to screw the housing 4 into the upper cavity 603 of the prechamber 6.

In some embodiments of the present application, as shown in FIG. 1, the pre-chamber spark plug assembly may further include a flat gasket 409, the flat gasket 409 being located between the housing 4 and the pre-chamber 6. Specifically, as shown in fig. 1-2, the housing 4 has a larger diameter at the stopper cavity 405, the housing 4 is provided with a housing external thread 404 at a position below the stopper cavity 405, and the inner diameter of the flat washer 409 is equal to the outer diameter of the housing 4 at the housing external thread 405. The flat washer 409 is sleeved outside the housing 4 from the lower end of the housing 4, so that the upper surface of the flat washer 409 is abutted against the outer lower end surface of the limit cavity 405. When the housing external thread 404 of the housing 4 is screwed into the upper cavity 603 of the prechamber 6, the lower surface of the flat washer 409 abuts against the outer upper end surface of the prechamber 6 to seal the gap at the threaded connection between the prechamber 6 and the housing 4.

In some embodiments of the present application, as shown in fig. 5, the lower outer wall of the prechamber 6 is provided with a prechamber outer thread 604, the cylinder head 7 of the engine is provided with an inner thread adapted to the prechamber 6, and the prechamber 6 is connected to the cylinder head 7 of the engine via the prechamber outer thread 604. Further, the external thread 601 of the prechamber can be located on the outer side wall of the lower cavity 601, the threaded hole (see fig. 1) on the cylinder head 7 is directly communicated with the main combustion chamber of the engine, and after the prechamber 6 is installed on the cylinder head 7 of the engine, the lower cavity 601 can be communicated with the main combustion chamber of the engine through the jet hole 605.

It should be noted that the housing external thread 404 and the prechamber external thread 604 are both left-handed threads or both right-handed threads, so as to avoid a loose connection between the housing 4 and the prechamber 6 when mounting the prechamber 6 in the cylinder head 7.

Since the cylinder head 7 requires high temperature compression ignition gas contact within the main combustion chamber of the engine, the cylinder head 7 needs to withstand a large pressure load. In order to seal the threaded connection of prechamber 6 and cylinder head 7, as shown in fig. 1, the prechamber spark plug assembly provided by embodiments of the present application may further include a prechamber gasket 8. The inner diameter of the prechamber gasket 8 is equal to the outer diameter of the prechamber 6 at the cone 601, and the prechamber gasket 8 is inserted from the lower end of the prechamber 6 to the upper end of the prechamber external thread 604. When prechamber 6 is in tight contact with cylinder head 7, prechamber gasket 8 is pressed between prechamber 6 and cylinder head 7 to seal the gap at the threaded connection between prechamber 6 and cylinder head 7.

Further, the heat insulator 2 referred to in the present application may be an insulating ceramic body having a good heat dissipation effect, and may be, for example, alumina ceramic, talc ceramic, mullite ceramic, cordierite ceramic, forsterite ceramic, or the like.

As shown in FIG. 6, the pre-chamber spark plug assembly may be assembled according to the following steps:

step S1, inserting the center electrode 1 into the heat insulator 2 from the upper end of the heat insulator 2;

step S2, mounting the heat insulator 2 in the case 4, and sealing the spark plug;

step S3, connecting the casing 4 of the prechamber spark plug to the prechamber 6;

step S4, the pre-chamber spark plug assembly is installed into the cylinder head 7.

In step S1, the center electrode 1 is inserted into the heat insulator 2, and the lower end 104 of the center electrode 1 is extended out of the heat insulator 2 from the end opening 201 while the lower surface of the ellipsoidal spherical part 102 is brought into contact with the first stopper surface 203 while the step surface 103 is brought into contact with the upper end of the heat insulator 2.

In step S2, installing the thermal insulation member 2 into the case 4 may further include installing the buffer structure 3 into the case 4. Specifically, the lower portion of the heat insulating material 2 is inserted into the housing 4 through the opening 406 such that the projection 202 is completely located in the stopper cavity 405 of the housing 4. Then, the buffer structure 3 is inserted into the heat insulating member 2 from the upper end of the heat insulating member 2, so that the lower surface of the buffer structure 3 abuts against the upper surface of the convex portion 202. The upper end of the case 4 is bent to reduce the diameter of the opening 406 to be smaller than the diameter of the projection 202, thereby preventing the heat insulator 2 from falling off the case 4.

The installation of the cushion structure 3 into the housing 4 includes inserting the lower gasket 303, the cushion collar 302, and the upper gasket 301 into the heat insulating material 2 in this order, and causing the lower gasket 303 to abut against the upper surface of the convex portion 202 and the upper gasket 301 to abut against the edge of the opening 406.

This step is the encapsulation of a pre-chamber spark plug, which spark plug 5 can also be used in conventional engines to solve the problem of conventional spark plug burn-out.

In step S3, mounting and fastening the pre-chamber spark plug to the pre-chamber 6 may include screwing the lower portion of the housing 4 into the internal thread of the upper cavity 603. Specifically, the flat washer 409 may be fitted to the outside of the housing 4 from the lower end of the housing 4, the prism 407 may be fixed by a tool, the housing 4 may be rotated to be connected to the precombustion chamber 6, the upper surface of the flat washer 409 may be abutted against the outer lower end surface of the limit cavity 405, and the lower surface of the flat washer 409 may be abutted against the outer upper end surface of the precombustion chamber 6. After assembly, the partition cavity 401 is communicated with the lower cavity 601.

In step S4, installing the pre-chamber spark plug assembly into the cylinder head 7 may include screwing the lower portion of the pre-chamber 6 into an internal thread of the cylinder head 7. Specifically, the prism 407 may be fixed by a tool and the housing 4 may be rotated to connect its pre-chamber spark plug assembly to the cylinder head 7. The lower cavity 601 of the pre-combustion chamber 6 is in communication with the main combustion chamber of the engine after assembly.

In a third aspect, embodiments of the present application further provide an engine including a pre-chamber spark plug assembly as described above. The pre-combustion chamber spark plug assembly is installed in a cylinder head 7 of an engine, a central electrode 1 and a side electrode 402 are communicated with a lower cavity 601, and the lower cavity 601 is communicated with a main combustion chamber of the engine through a jet hole 605. During the operation of the engine, fuel vapor is combusted in the lower cavity 601 and then ignited in the main combustion chamber through the jet holes 605. The heat in the lower cavity 601 can be dissipated through the housing of the prechamber 6. The heat insulation piece 2 and the central electrode 1 have a larger contact area, and the heat of the central electrode 1 can be transmitted to the shell 4 through the heat insulation piece 2 to be dissipated, so that the central electrode 1 is prevented from being overheated. The profile 100 can block heat from being transferred along the center electrode 1, and the center electrode 1 can be better protected.

In summary, in the prechamber spark plug assembly provided by the embodiment of the present application, the heat insulating member 2 surrounds the center electrode 1, the heat insulating member 2 and the center electrode 1 have a large contact area, and heat generated during ignition of the spark plug is easily dissipated from the heat insulating member 2. The precombustion chamber 6 comprises a lower cavity 601, fuel steam is combusted in the lower cavity 601, the volume of the lower cavity 601 is large, the combustion point of the fuel steam is not concentrated near the central electrode 1 and the side electrode 402, and the heat transferred to the side electrode 402 and the central electrode 1 can be effectively reduced. The side electrode 402 comprises a plurality of fan-shaped electrodes 4021, the fan-shaped electrodes 4021 have a large area, can endure higher temperature and have a better heat dissipation effect, the side electrode 402 and the center electrode 1 are prevented from being ablated, and the reliability of the spark plug is improved. The side electrodes 402 and the center electrode 1 need not be made of a large amount of precious metal, reducing the manufacturing difficulty and production cost of the pre-chamber spark plug assembly. The deformed portion 100 can reduce the heat transfer from the lower end portion 104 of the center electrode 1 to the upper portion of the center electrode 1, so that the heat of the center electrode 1 is mainly dissipated through the heat insulator 2, and the portion of the center electrode 1 above the deformed portion 100 does not need to be made of noble metal, but only the lower end portion 104 needs to be made of noble metal. The shell 4 and the prechamber 6 and the cylinder head 7 are connected by threads, which facilitates the mounting and dismounting of the spark plug in case of a failure of the spark plug.

In this application, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" means two or more unless expressly limited otherwise.

Although the present invention has been described with reference to the above embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. A pre-chamber spark plug assembly, characterized in that it comprises a spark plug (5), a pre-chamber (6) and a cylinder head (7), the lower part of the spark plug (5) being connected to the upper part of the pre-chamber (6), the lower part of the pre-chamber (6) being mounted in the cylinder head (7),

the precombustion chamber (6) comprises a long cylindrical lower cavity (601), the spark plug (5) is communicated with the lower cavity (601), and the lower cavity (601) penetrates through the cylinder cover (7).

2. The pre-chamber spark plug assembly of claim 1, wherein the inner diameter of the lower cavity (601) decreases from top to bottom.

3. The prechamber spark plug assembly of claim 2, characterized in that the bottom end of the prechamber (6) is provided with at least one jet hole (605), through which jet hole (605) the lower cavity (601) communicates with the main combustion chamber of the engine.

4. The pre-chamber spark plug assembly of claim 3, characterized in that the angle between the axis of the nozzle hole (605) and the axis of the lower cavity (601) in the direction towards the combustion chamber is in the range of 50 ° to 85 °.

5. A pre-chamber spark plug assembly according to claim 1, characterized in that the spark plug (5) comprises a central electrode (1), a heat shield (2) and a housing (4), the heat shield (2) surrounding the central electrode (1), a lower part of the heat shield (2) being mounted in the housing (4), the housing (4) comprising a partition cavity (401), a side electrode (402) being provided in the partition cavity (401), the central electrode (1) protruding from an end opening (201) of the heat shield (2) into the partition cavity (401), the side electrode (402) being spaced around the central electrode (1).

6. The pre-chamber spark plug assembly according to claim 5, characterized in that the center electrode (1) comprises a recess (101), the recess (101) being located at a lower part of the center electrode (1), and the recess (101) being surrounded by the thermal insulation (2).

7. The pre-chamber spark plug assembly of claim 5, wherein the thermal shield (2) comprises a boss (202), the housing (4) further comprising a check cavity (405), the boss (202) being located within the check cavity (405).

8. A pre-chamber spark plug assembly according to claim 7, characterized in that the spark plug (5) further comprises an upper gasket (301), a buffer sleeve (302) and a lower gasket (303), the upper gasket (301), the buffer sleeve (302) and the lower gasket (303) being surrounded between the outer wall of the thermal shield (2) and the inner wall of the confinement chamber (405).

9. The pre-chamber spark plug assembly of claim 5, wherein the thermal shield (2) is an insulating ceramic body.

10. An engine comprising a pre-chamber spark plug assembly as claimed in any one of claims 1 to 9.