Passive pre-combustion chamber spark plug

Abstract

The utility model discloses a passive pre-combustion chamber spark plug which comprises a pre-combustion chamber and an ignition gap structure arranged in the pre-combustion chamber. The pre-combustion chamber comprises a metal shell, an insulating ceramic body inserted into the metal shell and a pre-combustion chamber cap fixedly connected to the end, away from the insulating ceramic body, of the metal shell. Openings are formed in the two ends of the metal shell, the insulating ceramic body penetrates through the opening in one end, an ignition gap structure is fixedly connected to the end face, located in the metal shell, of the insulating ceramic body, and an interval is formed by the ignition gap structure and the pre-combustion chamber cap; and threads are formed on the outer surface of the metal shell. According to the invention, the integrated design is realized, the structure is compact, the ignition plug can be directly replaced with a conventional ignition plug, an engine cylinder cover does not need to be changed, and reliable ignition is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly relates to a passive pre-chamber spark plug. Background Art

[0002] Gasoline, due to its high ignition point, cannot be ignited by the compression ignition method when applied in automobiles, and a spark plug must be used. For gasoline engines, the spark plug is one of the essential key components.

[0003] Research shows that the lean combustion technology has great potential in energy conservation and emission reduction of gasoline engines. However, the lean mixture will delay the ignition and combustion processes, and the too-low combustion speed will significantly postpone the combustion phase and increase the combustion cycle variation rate. Research shows that achieving in-cylinder lean combustion requires high ignition energy and a long ignition duration. In the lean-burn gasoline engines that have been developed so far, combustion instability and catalyst incompatibility are two major problems. Aiming at the disadvantage that it is difficult to achieve high-quality combustion using a traditional spark plug system under lean combustion conditions, researchers have tried many new high-energy and high-efficiency ignition technologies, such as laser ignition technology, multi-spark ignition technology, multi-center electrode ignition technology, pre-chamber ignition technology, etc. Among them, the most promising one is the pre-chamber ignition technology. Some research believes that the pre-chamber ignition system is significantly superior to the traditional spark ignition system in improving the fuel economy of engines.

[0004] Currently, foreign countries have tried to apply the pre-chamber ignition technology to conventional gasoline engines and obtained some results. Domestic is trying to apply the pre-chamber ignition technology to existing engines. Relevant research shows that there are problems such as insufficient scavenging, a high proportion of residual exhaust gas, and poor ignition under small loads. To improve the above problems, it is necessary to continuously optimize the pre-chamber structure.

[0005] After searching, no patent technical literature reports related to the pre-chamber spark plug and engine characteristics described in the present invention have been found. The closest patent literatures are as follows:

[0006] 1. An invention patent with the patent number CN 111917005 A and the name "Spark Plug", which discloses a pre-chamber spark plug structure. Its structural features are: a single-sided electrode, a straight-sided electrode is welded on the threaded surface of the metal shell, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0007] 2. An invention patent with the patent number CN 111917007 A and the name "Spark Plug", which discloses a pre-chamber spark plug structure. Its structural features are: a single-sided electrode, a straight-sided electrode is welded on the threaded surface of the metal shell, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0008] 3. The invention patent with the patent number CN 110676692 B and the name "Spark Plug" discloses a pre-chamber spark plug structure, and its structural features are: a single-sided electrode, a J-shaped side electrode welded to the end of the metal shell, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0009] 4. The invention patent with the patent number CN 112313845 A and the name "Pre-chamber Spark Plug with a Ground Electrode Symmetrically Arranged Inside the Shell" discloses a pre-chamber spark plug structure, and its structural features are: double-sided electrodes, a straight side electrode welded to the end of the metal shell, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0010] 5. The patent with the patent number CN 109378710 A and the name "A Spark Plug with a Pre-chamber Structure" discloses a pre-chamber spark plug structure, and its structural features are: a single-sided electrode, a J-shaped side electrode welded to the end of the metal shell, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0011] 6. The patent with the patent number CN 111577445 A and the name "Pre-chamber Device with a Residual Exhaust Gas Chamber and Its Installation Structure" discloses a split pre-chamber spark plug structure, and its structural features are: adopting a main body cavity + a conventional spark plug, a single-sided electrode, and the pre-chamber jet holes are cylindrical through holes with a unified diameter.

[0012] Through the descriptions of the above patents, it is found that: some of the above patents adopt a split design, which

[0013] requires modifications to the original engine cylinder head. The modification is difficult and costly, and it is not conducive to product mass production; the above patents generally adopt the direct welding of the side electrode on the threaded surface of the metal shell. This design has a complex process and high production cost, and it is also not conducive to product mass production. Summary of the Invention

[0014] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a passive pre-chamber spark plug to solve the problems of high cost of the passive pre-chamber spark plug itself and the large difficulty and high cost of engine modification in the application of the split pre-chamber. To achieve the above object and other advantages of the present invention, a passive pre-chamber spark plug is provided, including:

[0015] A pre-chamber and an ignition gap structure arranged in the pre-chamber;

[0016] Wherein, the pre-chamber includes a metal shell, an insulating ceramic body inserted into the metal shell, and a pre-chamber cap fixedly connected to one end of the metal shell away from the insulating ceramic body;

[0017] Both ends of the metal housing are open. An insulating ceramic body passes through one of the open ends, and an ignition gap structure is fixedly connected to the end face of the insulating ceramic body located inside the metal housing. The ignition gap structure and the pre-combustion chamber cap form an interval.

[0018] Threads are provided on the outer surface of the metal housing.

[0019] Preferably, the ignition gap structure includes an inner washer-side electrode assembly and a center electrode fixedly disposed at one end of the inner washer-side electrode assembly.

[0020] Preferably, the inner washer-side electrode assembly includes an inner washer and a plurality of side electrodes fixedly connected to the inner washer and evenly distributed. The ends of adjacent side electrodes among the plurality of side electrodes are evenly distributed at a certain angle on the projection plane perpendicular to the axis of the spark plug.

[0021] Preferably, a plurality of pre-combustion chamber jet holes are evenly provided on the surface of the pre-combustion chamber cap. The center line of each pre-combustion chamber jet hole intersects the center line of the pre-combustion chamber spark plug at the same point.

[0022] . A passive pre-combustion chamber spark plug according to the claim, wherein the center line of each pre-combustion chamber jet hole forms an equal angle with the center line of the pre-combustion chamber spark plug, and the angle range is 50° to 80°.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) One-piece design, compact structure, can be directly replaced with a conventional spark plug without modifying the engine cylinder head.

[0025] (2) Adopt an integrated design of the inner washer-side electrode combination type, which has a simple process. Avoid the design of directly welding the side electrode with complex process and high production cost on the threaded surface of the metal housing, and it is easy to realize product cost control and mass production.

[0026] (3) Adopt 4 side electrodes to cope with the complex oil-gas mixing airflow field and concentration field inside the pre-combustion chamber and achieve reliable ignition.

[0027] (4) Adopt the design of 6 pre-combustion chamber holes, which can make full use of the tumble in the cylinder and make the scavenging in the pre-combustion chamber more thorough. Brief Description of the Drawings

[0028] Figure 1 It is a half-sectional structure schematic diagram of a passive pre-combustion chamber spark plug according to the present invention;

[0029] Figure 2 It is a structure schematic diagram of the inner washer-side electrode assembly of a passive pre-combustion chamber spark plug according to the present invention;

[0030] Figure 3 Schematic diagram of the key dimensions of the inner point coil-side electrode assembly of the passive pre-chamber spark plug according to the present invention;

[0031] Figure 4 Schematic diagram of the positional relationship and gap between the inner washer-side electrode assembly and the center electrode of the passive pre-chamber spark plug according to the present invention;

[0032] Figure 5 Schematic diagram of the semi-sectional structure of the pre-chamber cap of the passive pre-chamber spark plug according to the present invention;

[0033] Figure 6 Schematic diagram of the semi-sectional structure of the pre-chamber cap and the inner washer-side electrode assembly of the passive pre-chamber spark plug according to the present invention;

[0034] Figure 7 Schematic diagram of the three-dimensional structure of the passive pre-chamber spark plug according to the present invention. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0036] Referring to Figure 1 and 7 , a passive pre-chamber spark plug includes: a pre-chamber 10 and an ignition gap structure disposed in the pre-chamber 10;

[0037] Among them, the pre-chamber 10 includes a metal housing 5, an insulating ceramic body 2 inserted into the metal housing 5, and a pre-chamber cap 11 fixedly connected to one end of the metal housing 5 away from the insulating ceramic body 2; a wiring screw 3 is disposed in the insulating ceramic body 2. A talc ring 4 is disposed at the middle contact portion between the metal housing 5 and the insulating ceramic body 2. One end of the insulating ceramic body 2 away from the pre-chamber cap 11 is fixedly connected to a terminal cap 1.

[0038] The pre-chamber cap 11 is coaxial with the metal housing and welded to the metal housing.

[0039] As Figure 1 , an outer washer 6 is sleeved outside the metal housing 5. The outer washer 6 is used to be installed at the flange of the metal housing to realize the gas sealing function between the spark plug and the cylinder head.

[0040] As Figure 1, an in-built resistor 7 is placed inside one end of the insulating ceramic body 2 close to the inner washer-side electrode assembly 8. The in-built resistor 7 is coaxial with the insulating ceramic body 2 and both have an electromagnetic radiation suppression effect.

[0041] Both ends of the metal housing 5 are open. The insulating ceramic body 2 passes through one of the open ends, and an ignition gap structure is fixedly connected to the end face of the insulating ceramic body 2 inside the metal housing 5. The ignition gap structure and the pre-chamber cap 11 form an interval.

[0042] Furthermore, threads are provided on the outer surface of the metal housing 5, and the metal housing 5 is fitted to the engine cylinder head through the threads. This enables the passive pre-chamber spark plug of the present application to be directly assembled on the engine cylinder head without any modification to the engine cylinder head.

[0043] Furthermore, as Figure 2 shown, the ignition gap structure includes an inner washer-side electrode assembly 8 and a center electrode 9 fixedly connected to one end of the inner washer-side electrode assembly 8. The center electrode 9 is coaxial with the end cap and the connection screw rod and is located at the firing part of the insulating ceramic body 2. The inner washer-side electrode assembly 8 includes an inner washer and a plurality of side electrodes 82 fixedly connected to the inner washer and evenly distributed. The ends of adjacent side electrodes among the plurality of side electrodes are evenly distributed at 90 degrees on the projection plane perpendicular to the axis of the spark plug. The inner washer-side electrode assembly 8 is a spatial configuration. The integrated design of the inner washer-side electrode assembly 8 not only considers the fixation and sealing between the spark plug ceramic body and the spark plug housing but also has the function of the side electrodes of the spark plug; this is significantly different from the separate design of the side electrodes of traditional pre-chamber spark plugs.

[0044] Furthermore, 4 side electrodes 82 are evenly distributed on the inner washer 81. The ends of adjacent side electrodes among these 4 side electrodes are evenly distributed at 90 degrees on the projection plane perpendicular to the axis of the spark plug. The inner washer-side electrode assembly 8 extends along the inner washer that plays a sealing role between the insulating ceramic body 2 and the metal housing 5 and is distributed along the surface of the insulating ceramic body.

[0045] Furthermore, the positional relationship and gap between the inner washer-side electrode assembly 8 and the center electrode 9 in the passive pre-chamber spark plug are as Figure 4 .

[0046] Furthermore, a plurality of pre-chamber jet holes 12 are evenly provided on the surface of the pre-chamber cap 11. The center line of each pre-chamber jet hole 12 intersects the center line of the pre-chamber spark plug at the same point. The shape of the pre-chamber jet hole 12 is a cylindrical through-hole. And the pre-chamber jet hole 12 is used to realize the exchange of substances and energy inside and outside the pre-chamber.

[0047] Furthermore, the dimensions and relative positional relationship of the pre-chamber jet holes 12 are asFigure 3 As can be seen from the figure, for each pre-chamber jet hole of this passive pre-chamber spark plug, the center line intersects with the center line of the pre-chamber spark plug at the same point, and the included angle between the center line of each jet hole and the center line of the pre-chamber spark plug is equal; this included angle is 50° to 80°.

[0048] The structure of this application adopts an integrated design, which is compact and can be directly replaced with a conventional spark plug without modifying the engine cylinder head.

[0049] It adopts an integrated design of an inner washer-side electrode combination type, and this method has a simple process. It avoids the design of directly welding the side electrode, which has a complex process and high production cost, on the threaded surface of the metal shell, and is easy to achieve product cost control and mass production.

[0050] It adopts the method of 4 side electrodes to cope with the complex oil-gas mixing airflow field and concentration field inside the pre-chamber and achieve reliable ignition.

[0051] It adopts the design of 6 pre-chamber holes, which can make full use of the tumble in the cylinder and make the scavenging in the pre-chamber more thorough.

[0052] The equipment quantity and processing scale described here are used to simplify the description of the present invention, and the application, modification and variation of the present invention are obvious to those skilled in the art.

[0053] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples described here.

Claims

1. A passive pre-chamber spark plug, characterized in that, Comprising: A pre-chamber (10) and an ignition gap structure disposed within the pre-chamber (10); Wherein, the pre-chamber (10) includes a metal housing (5), an insulating ceramic body (2) inserted into the metal housing (5), and a pre-chamber cap (11) fixedly connected to one end of the metal housing (5) away from the insulating ceramic body (2); Both ends of the metal housing (5) are open, and at one end opening, the insulating ceramic body (2) passes through, and an ignition gap structure is fixedly connected to the end surface of the insulating ceramic body (2) located within the metal housing (5), and the ignition gap structure and the pre-chamber cap (11) form an interval; Threads are provided on the outer surface of the metal housing (5).

2. The passive pre-chamber spark plug according to claim 1, characterized in that, The ignition gap structure includes an inner washer-side electrode assembly (8) and a center electrode (9) fixedly connected to one end of the inner washer-side electrode assembly (8).

3. The passive pre-chamber spark plug according to claim 2, wherein The inner washer-side electrode assembly (8) includes an inner washer and a plurality of side electrodes fixedly connected to the inner washer and evenly distributed. The ends of adjacent side electrodes among the plurality of side electrodes are evenly distributed at 90 degrees on a projection plane perpendicular to the axis of the spark plug.

4. The passive pre-chamber spark plug according to claim 1, characterized in that, A plurality of pre-chamber jet holes (12) are evenly provided on the surface of the pre-chamber cap (11), and the center line of each pre-chamber jet hole (12) intersects the center line of the pre-chamber spark plug at the same point.

5. The passive pre-chamber spark plug according to claim 4, wherein, The angle between the center line of each pre-chamber jet hole (12) and the center line of the pre-chamber spark plug is equal, and the angle range is 50° to 80°.

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