Spark plug gasket crush limiter
By introducing a gasket crush limiter into the spark plug assembly, the problem of seals being crushed under excessive torsion is solved, maintaining sealing performance, reducing maintenance needs, and improving engine reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CATERPILLAR INC
- Filing Date
- 2021-04-25
- Publication Date
- 2026-07-14
Smart Images
Figure CN113612111B_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to spark plugs and gaskets / seals used in internal combustion engines to prevent gases from being blown out of the combustion chamber through a gap located between the cylinder head and the spark plug. More specifically, this disclosure relates to a spark plug having the feature of limiting the amount of compression applied to the gasket / seal. Background Technology
[0002] Internal combustion engines are frequently used in various industries to power machines and equipment. Examples of industries using such machines and equipment include marine, earthmoving, construction, mining, locomotives, and agriculture. Some of these engines employ spark plugs with a washer or seal inserted between the spark plug and a spark plug bore in the cylinder head. These seals or washers help prevent high-pressure gases from escaping through the spark plug bore into the combustion chamber (sometimes referred to as "blow-through"). For maintenance purposes, these spark plugs are periodically unscrewed from the cylinder head. New or refurbished spark plugs are then provided by screwing them back on so that their external threads engage with the internal threads of the spark plug bore.
[0003] More specifically, mechanical devices can use a wrench or socket wrench to engage the hexagonal portion of the spark plug to properly tighten it. However, over-twisting the spark plug can cause it to press excessively against the seal / gasket across its sealing engagement surface. Technically, this can be described as "crushing" the seal and gasket. If the deformation is permanent (plastic), it can cause the gasket / seal to lose the elasticity necessary to prevent "leakage." This can lead to poor performance and thus unwanted additional maintenance.
[0004] U.S. Patent No. 9,787,063 granted to Niessner discloses a sealing ring for a spark plug having external threads for screwing into an internal combustion engine, a collar, and a threaded undercut located between the external threads and the collar. The sealing ring comprises an annular solid sealing element made of metal. The sealing element has two planar annular sealing surfaces arranged parallel to each other. An annular retaining element, made of elastomer, for self-retaining engagement of the threaded undercut of the spark plug, is attached to the sealing element on its inner annular side. Furthermore, spark plugs including such sealing rings and internal combustion engines including such spark plugs exist. Summary of the Invention
[0005] An internal combustion engine according to embodiments of the present disclosure may include: a cylinder head including a flame deck surface that at least partially defines a combustion chamber; a spark plug receiver orifice defining a longitudinal axis, a radial direction, and a circumferential direction, and including an enlarged diameter portion and a reduced diameter portion, the enlarged diameter portion including an axially upward sealing surface, and the reduced diameter portion including internal threads. The engine may also include a spark plug including: a front axial portion including external threads engaging with the internal threads of the reduced diameter portion of the spark plug receiver orifice; and an intermediate axial collar portion defining an axially downward sealing surface. A gasket may be axially disposed between the axially upward sealing surface of the spark plug receiver orifice and the axially downward sealing surface of the spark plug. The spark plug may further include a gasket crushing limiter including a wall extending radially outward and axially downward from the intermediate axial collar portion toward the axially upward sealing surface of the spark plug receiver orifice, thereby radially wrapping around the gasket.
[0006] A spark plug assembly according to an embodiment of the present disclosure may include a spark plug comprising a rotating body defining a longitudinal axis, a radial direction, and a circumferential direction. The spark plug may further include: a front axial portion including external threads; an intermediate axial collar portion defining an axially downward sealing surface; and a first electrode and a second electrode extending from the front axial portion, the first electrode and the second electrode defining a spark gap therebetween. A gasket may be axially disposed between the axially downward sealing surface and the external threads of the front axial portion. The spark plug also includes a gasket crushing limiter including walls extending radially outward and axially downward from the intermediate axial collar portion, thereby defining an annular recess having a radially outer recess wall that at least partially radially surrounds the gasket.
[0007] A spark plug according to an embodiment of the present disclosure may include a rotating body defining a longitudinal axis, a radial direction, and a circumferential direction. The spark plug may further include: a front axial portion including external threads; an intermediate axial collar portion defining an axially downward sealing surface; and a first electrode and a second electrode extending from the front axial portion and defining a spark gap therebetween. A hexagonal drive portion may be axially disposed above the intermediate collar portion. The spark plug also includes a washer crushing limiter including a wall extending axially downward from the intermediate axial collar portion, defining an annular recess formed by the wall and the front axial portion. Attached Figure Description
[0008] Figure 1 This is a cross-sectional side view of an internal combustion engine employing spark plugs and spark plug assemblies with gaskets / seals, according to various embodiments of the present disclosure.
[0009] Figure 2According to embodiments of this disclosure Figure 1 An enlarged cross-sectional side view of an internal combustion engine, which more clearly shows the spark plug assembly gaskets / seals and gasket crush limiters.
[0010] Figure 3 It was removed from the engine to enhance clarity. Figure 1 and 2 A partial cross-sectional side view of a spark plug assembly.
[0011] Figure 4 yes Figure 2 An enlarged perspective view of the spark plug, showing the gasket extending freely from the recess of the gasket crusher limiter. Detailed Implementation
[0012] Reference will now be made in detail to embodiments of this disclosure, examples of which are illustrated in the accompanying drawings. Throughout the drawings, the same reference numerals will be used wherever possible to denote the same or similar parts. In some cases, the reference numerals will be indicated in this specification, and the drawings will show reference numerals followed by letters (e.g., 100a, 100b) or by apostrophes (e.g., 100', 100"). It should be understood that the use of letters or apostrophes immediately following reference numerals is to indicate that these features have similar shapes and similar functions, which is often the case when the geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters or apostrophes are often not included herein but may be shown in the drawings to indicate that they are copies of features discussed in this written specification.
[0013] Various embodiments of spark plugs or spark plug assemblies that can be used in internal combustion engines according to various embodiments of the present disclosure will now be described. More specifically, the spark plug or spark plug assembly may include a gasket crushing limiter, which will be described in detail.
[0014] For example, Figure 1 An internal combustion engine 100 is shown, which may employ various embodiments of spark plugs or spark plug assemblies constructed according to the principles set forth herein. The engine 100 may include an engine block (not clearly shown) in which pistons (not shown) reciprocate, and a cylinder head 104 that may include various engine components for introducing fluid into a bore / combustion chamber 106 located in the engine block, as well as spark plug assemblies 200 and / or spark plugs 300. It should be understood that spark plugs themselves are typically (but not necessarily) subassemblies consisting of multiple parts.
[0015] More specifically, engine 100 includes cylinder head 104 having a flame-retardant layer surface 110 that at least partially defines a combustion chamber 106. Spark plug assembly 200 or spark plug 300 extends through the surface 110 into the combustion chamber 106 to ignite the fuel / air mixture during engine 100 operation.
[0016] The cylinder head 104 has a spark plug receiving hole 112 defining a longitudinal axis 114, a radial direction 116, and a circumferential direction 118. For example, the hole 112 may have a cylindrical or conical shape. Therefore, the hole 112 includes an enlarged diameter portion 120 and a reduced diameter portion 124, the enlarged diameter portion including an axially upward sealing surface 122, and the reduced diameter portion including an internal thread 126. The portion 124 is axially positioned below the portion 120, but this is not always the case.
[0017] Spark plug 300 may be disposed in spark plug receiving hole 112. Spark plug 300 may include a front axial portion 302, which includes an external thread 304 that engages with an internal thread 126 of a reduced diameter portion 124 of spark plug receiving hole 112 (see also...). Figure 2 ), and an intermediate axial collar portion 306 that defines an axially downward sealing surface 308 that is relative to the axially upward sealing surface 122.
[0018] like Figure 1 and 2 As seen, the washer 128 can be axially disposed between the axially upward sealing surface 122 of the spark plug receiving hole 112 and the axially downward sealing surface 308 of the spark plug 300. The washer can be any suitable shape, including O-ring shape, square ring shape, U-shape, etc.
[0019] like Figure 2 As best seen, spark plug 300 further includes a gasket crushing limiter 310, which includes a wall 312 extending radially outward and axially downward from the intermediate axial collar portion 306 toward the axially upward sealing surface 122 of the spark plug receiving hole 112. The wall 312 may partially or completely radially surround the gasket 128.
[0020] Once the spark plug 300 is fully installed, the wall 312 of the washer crush limiter 310 can contact the axially upward sealing surface 122 of the spark plug receiving hole 112. The wall 312 and the washer 128 can be configured such that the washer cannot be over-compressed. In a particular embodiment of this disclosure, the washer 128 includes a serpentine shape (i.e., having at least one bend) comprising straight portions 130 that are at least partially axially spaced from each other (i.e., parallel to axis 114). In other words, in spring terminology, the washer is not fully compressed to its solid length or solid state.
[0021] Washers can be made from various types of materials, including elastomers, rubber, metals, aluminum, stainless steel, etc. For example... Figure 2 As shown, the washer 128 is made of metal bent into a serpentine shape and defines a minimum washer wall thickness 132, and the wall 312 of the washer crushing limiter 310 defines a radial wall thickness 314 greater than the minimum washer wall thickness 132.
[0022] As previously mentioned herein, spark plug 300 can be a sub-assembly. Therefore, the wall of gasket crush limiter 310 can be a separate component attached to the spark plug. On the other hand, the wall 312 of gasket crush limiter 310 can be connected to, for example... Figure 2 The intermediate axial collar portion 306 of the spark plug shown is integral (i.e., composed of a single piece).
[0023] Similarly, as Figure 1 As seen, the cylinder head 104 can also be formed as a subassembly. For example, the cylinder head 104 may define a spark plug sleeve receiving port 133, a cooling chamber 134 communicating with the spark plug sleeve receiving port 133, and a spark plug sleeve 136 disposed in the spark plug sleeve receiving port 133. Due to this arrangement, the spark plug sleeve 136 is at least partially surrounded by the cooling chamber 134, and the spark plug receiving port 112 is defined by the spark plug sleeve 136. Therefore, the spark plug is separated and / or isolated from the cooling chamber 134 and any cooling fluid in that chamber. The spark plug sleeve 136 has at least a partially annular shape (e.g., cylindrical, conical, etc.) around a longitudinal axis 114, thereby forming a spark plug receiving port 112 for receiving the spark plug 300.
[0024] The goal is to separate the cooling fluid from the combustion chamber 106 and its gases, as well as the spark plug sleeve receiver hole 133, and vice versa. Therefore, a lower axial seal 138 may be disposed between the spark plug sleeve 136 and the cylinder head 104, and an upper axial seal 140 may be disposed between the spark plug sleeve 136 and the cylinder head 104.
[0025] exist Figure 2 In this configuration, spark plug 300 may define an external thread undercut 316 (in the radial direction) axially disposed between the external thread 304 of the front axial portion 302 and the axially downward sealing surface 308 of the intermediate axial collar portion 306. Washer 128 may include a leg 142 extending radially into the external thread undercut 316 to form assembly 200. That is, during installation and removal, the washer will naturally remain on the spark plug because it cannot be axially removed from the spark plug unless intentionally pried or screwed through the thread 304, etc.
[0026] Reference Figure 3The spark plug 300a may further include two electrodes (e.g., a center electrode 318 and a ground electrode 320) extending from the front axial portion 302 and defining a spark gap 322 therebetween. In some embodiments of this disclosure, at least one of the two electrodes (e.g., the ground electrode 320) defines an axial end 324 of the spark plug 300a that is axially spaced 324 from the flame-retardant layer surface 110a by a predetermined axial distance 324 (e.g., when the wall 312 of the gasket crush limiter 310 contacts the axially upward sealing surface 122 of the cylinder head 104). Figure 2 (as shown in the image).
[0027] in addition, Figure 3 At least one of the two electrodes (e.g., ground electrode 320) may extend at least partially radially from a point near the external thread 304, and the circumferential orientation of at least one electrode may be predetermined (e.g., when the wall 312 of the gasket crusher 310 contacts the axially upward sealing surface 122 of the cylinder head 104). Figure 2 (as shown in the image).
[0028] In other words, the relative configuration of the spark plug wall and gasket, as well as the engagement timing between the internal and external threads, can be selectively chosen to ensure consistent position and orientation of the spark plug and its components, as well as the gasket, each time the spark plug is fully tightened. This may not be the case for other embodiments of this disclosure.
[0029] Next, spark plug assemblies 200, 200a, which can be provided as alternative parts / assemblies according to various embodiments of the present disclosure, will be described.
[0030] Go to Figure 1 and 3 Two examples of this spark plug assembly, 200 and 200a, can be seen. It should be understood that, as... Figure 1 The spark plug assembly 200 shown can be used with Figure 3 The spark plug assembly 200a is similarly constructed, with components having slightly different configurations, proportions and / or materials.
[0031] Spark plug assemblies 200, 200a can be constructed as follows. Washer 128, as previously described, can be held on spark plugs 300, 300a in a manner previously discussed herein (e.g., by a portion of a washer extending into the undercut of the external thread). This simplifies installation and helps prevent damage to washer 128 during installation.
[0032] Spark plugs 300, 300a may include a sleeve-shaped spark plug body 324, 324a made of metal and an elongated insulator 326, 326a made of ceramic. More generally, the bodies 324, 324a are characterized by rotation, as their geometry is generated at least in part by rotating a geometric cross-section about a longitudinal axis 332, thereby further defining a radial direction 334 and a circumferential direction 336. The insulators 326, 326a may surround an inner conductor 328, 328a, which, through… Figure 3 Glass seal 329a or Figure 2 The inner washer 329 is connected to the center electrode 318 inside the insulators 326 and 326a.
[0033] Key references Figure 3 A ground electrode 320, forming a spark gap 322 with the center electrode 318, is attached to the spark plug body 324a. Electrodes 318 and 320 are arranged at the front axial portion 302a of the spark plug 324 (and therefore the spark plug body 324a), which protrudes into the combustion chamber in the installed state. At the front axial portion 302a, the spark plug body 324a has external threads 304 for screwing the spark plug into the corresponding internal threads of the spark plug bore in the cylinder head of the internal combustion engine.
[0034] The beginning of the first threaded turn is designated as the thread initiation point 330 and may have a defined circumferential position / orientation relative to the ground electrode 320. After being screwed into the internal combustion engine, the section of the ground electrode 320 extending transversely to the longitudinal axis 332 of the spark plug 300a (hereinafter referred to as the radial extension) may then have a predetermined angle relative to the crankshaft (not shown). This may not be the case for other embodiments of this disclosure.
[0035] The spark plug body 324a may also have an intermediate axial collar portion 306, which is arranged on the side of the external thread 304 opposite to the front axial portion 302a. A hexagonal drive portion 338 may also be provided, which is axially positioned above the intermediate axial collar portion 306.
[0036] As mentioned above Figure 2 The spark plugs 300 and 300a may further include a gasket crushing limiter 310, which includes a wall 312 extending radially outward and axially downward from the intermediate axial collar portion 306, thereby defining an annular recess 338 having a radially outward recessed surface 339 that at least partially radially surrounds the gasket 128.
[0037] The annular recess 338 can be in a plane including the longitudinal axis 332 and the radial direction 334 (e.g., Figure 2 and Figure 4The cross-section defines an axial depth 340 and a radial width 342 greater than the axial depth 340. The washer 128 may define a washerless height 144, measured along axis 322, which is greater than the axial depth 340, and in some embodiments, the ratio of the difference between the washerless height 144 and the axial depth 340 divided by the washerless height 144 may be in the range of 20% to 50%. In some embodiments, this range may be 25% to 35%. Other dimensional ranges and proportions are possible in other embodiments of this disclosure.
[0038] Additionally, the annular recess 338 may define an outer diameter 344, and the wall 312 of the washer crushing limiter 310 defines an outer diameter 346. In some embodiments, the washer 128 defines a minimum washer wall thickness 132, which is less than the radial wall thickness 314 of the wall 312 of the washer crushing limiter 310. In other words, the radial wall thickness 314 may be greater than the minimum washer wall thickness 132.
[0039] exist Figure 2 In some of the best-seen embodiments, the gasket 128 may comprise an undulating strip (i.e., having at least one vertex) material defining a minimum wall thickness 132, and the wall 312 of the gasket crushing limiter 310 may define a radial wall thickness 314 that is at least 2.0 times greater than the minimum wall thickness 132. This may not be the case for other embodiments of this disclosure.
[0040] Now, you can continue to refer to it. Figure 2 Let us discuss embodiments of spark plugs 300, 300a provided as replacement parts / subassemblies.
[0041] The washer crush limiter 310 may include a wall 312 extending axially downward from the intermediate axial collar portion 306, defining an annular recess 338 formed by the wall 312 and the front axial portion 302. In this case, the intermediate axial collar portion 306 may not be like... Figures 2 to 4 The land shown is flared.
[0042] However, in Figures 2 to 4 In some embodiments of this disclosure shown, the intermediate axial collar portion 306 may be flared and includes a transition surface 348 (radial, elliptical, polygonal, conical, etc.) extending axially downward and radially outward from the intermediate axial collar portion 306 to the wall 312. As shown, the transition surface 348 may be conical.
[0043] Key references Figure 2The annular recess 338 is defined by a planar, axially downward sealing surface 308, a cylindrical outer peripheral surface 350 extending from the axially downward sealing surface 308, and a conical inner peripheral surface 352 extending from the axially downward sealing surface 308. In other embodiments of this disclosure, any one of these surfaces 308, 350, and 352 may be configured differently.
[0044] In some embodiments, the wall 312 of the washer crushing limiter 310 terminates at a plane 354 perpendicular to the longitudinal axis 332, and the inner circumferential surface 352 may terminate at the same plane 354. This may not be the case for other embodiments of this disclosure.
[0045] Depending on the application, the configuration and size range of any of the embodiments discussed herein may vary.
[0046] Spark plugs and gaskets can be manufactured using any suitable manufacturing process from any suitable material, including but not limited to any manufacturing process specifically, implicitly, or inherently described herein.
[0047] Industrial applicability
[0048] In practice, spark plugs, spark plug assemblies, and / or engine assemblies using any of the embodiments described herein may be supplied, sold, manufactured, and purchased as needed or desired by the aftermarket or OEMs (Original Equipment Manufacturers). For example, spark plugs or spark plug assemblies may be used to retrofit existing engines already in the field, or may be sold together with the engine or equipment using the engine at the device's first point of sale.
[0049] Various embodiments can reduce engine maintenance due to less damage to the spark plug gaskets. Additionally, proper positioning and / or orientation of the spark plug electrodes can be provided more reliably.
[0050] Furthermore, the disclosed dimensional ranges and / or scale ranges can provide key results not taught in the prior art. Specifically, these variables can allow the gasket crush limiter wall to absorb 90% or more of the axial load generated when the spark plug is tightened, helping to protect the gasket from excessive compression or crushing. Additionally, the recess for receiving the gasket, and the features defining and / or surrounding the recess, can help keep the gasket away from the bottom sealing surface of the limiter wall, preventing the gasket from clamping during installation, etc.
[0051] It should be understood that the foregoing description provides examples of the disclosed components and techniques. However, it is conceivable that other embodiments of this disclosure may differ in detail from the foregoing examples. All references to this disclosure or examples thereof are intended to refer to the specific examples discussed at the time and are not intended to imply any limitation on the scope of this disclosure in a more general sense. All distinctions and adverse statements regarding certain features are intended to indicate that such features are not preferred, but are not intended to completely exclude such features from the scope of the invention unless otherwise specified.
[0052] Unless otherwise indicated herein, the description of value ranges herein is intended only as a shorthand method for referring to each independent value falling within the range, and each independent value is incorporated into the specification as if described separately herein.
[0053] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the devices and assembly methods discussed herein without departing from the scope or spirit of the invention. Other embodiments of this disclosure will be apparent to those skilled in the art in light of the description and implementation of the various embodiments disclosed herein. For example, some devices may be constructed and function differently from those described herein, and certain steps of any method may be omitted, performed in a different order than specifically mentioned, or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications can be made to certain aspects or features of the various embodiments to produce other embodiments, and features and aspects of the various embodiments may supplement or substitute other features or aspects of other embodiments to provide other embodiments.
[0054] Therefore, as permitted by applicable law, this disclosure includes all modifications and equivalents to the subject matter set forth in the appended claims. Furthermore, unless otherwise indicated herein or clearly contradicted by the context, this disclosure covers any combination of the foregoing elements in all possible variations.
Claims
1. An internal combustion engine, comprising: Cylinder head, the cylinder head comprising: The flame-retardant layer surface at least partially defines the combustion chamber; A spark plug receiving hole, the spark plug receiving hole defining a longitudinal axis, a radial direction and a circumferential direction, and including an enlarged diameter portion and a reduced diameter portion, the enlarged diameter portion including an axially upward sealing surface, the reduced diameter portion including an internal thread; Spark plug, the spark plug including a front axial portion and an intermediate axial collar portion, the front axial portion including an external thread that engages with an internal thread of the reduced diameter portion of the spark plug receiving hole, the intermediate axial collar portion defining an axially downward sealing surface; and A washer, the washer being axially disposed between the axially upward sealing surface of the spark plug receiving hole and the axially downward sealing surface of the spark plug; The spark plug further includes a gasket crushing limiter, the gasket crushing limiter including a wall extending radially outward and axially downward from the intermediate axial collar portion toward the axially upward sealing surface of the spark plug receiving hole, and radially wrapping around the gasket.
2. The internal combustion engine of claim 1, wherein the wall of the gasket crushing limiter contacts the axially upward sealing surface, and the gasket comprises a serpentine shape including at least partially straight portions axially spaced apart from each other.
3. The internal combustion engine according to claim 1, wherein the wall of the gasket crushing limiter is integral with the intermediate axial collar portion.
4. The internal combustion engine of claim 1, wherein the cylinder head defines a spark plug sleeve receiving hole, a cooling chamber communicating with the spark plug sleeve receiving hole, and a spark plug sleeve disposed in the spark plug sleeve receiving hole and at least partially surrounded by the cooling chamber.
5. The internal combustion engine of claim 4, wherein the spark plug receiving hole is defined by the spark plug sleeve, and the spark plug sleeve has at least a partially annular shape around the longitudinal axis.
6. The internal combustion engine according to claim 5, further comprising a lower axial seal disposed between the spark plug sleeve and the cylinder head, and an upper axial seal disposed between the spark plug sleeve and the cylinder head.
7. The internal combustion engine of claim 2, wherein the spark plug defines an external thread undercut axially disposed between the external thread of the front axial portion and the axially downward sealing surface of the intermediate axial collar portion, and the washer includes a leg extending radially into the external thread undercut.
8. The internal combustion engine of claim 1, wherein the gasket defines a minimum gasket thickness, and the wall of the gasket crushing limiter defines a radial wall thickness greater than the minimum gasket thickness.
9. The internal combustion engine of claim 1, wherein the spark plug further comprises two electrodes extending from the front axial portion and defining a spark gap therebetween, and at least one of the two electrodes defining an axial end of the spark plug, wherein the axial end of the spark plug is axially spaced from the flame-retardant layer surface by a predetermined axial distance when the wall of the gasket crush limiter contacts the axially upward sealing surface.
10. The internal combustion engine of claim 1, wherein the spark plug further comprises two electrodes extending from the front axial portion and defining a spark gap therebetween, and at least one of the electrodes extending radially at least partially from a point proximal to the external thread, and the circumferential orientation of the at least one electrode is predetermined when the wall of the crushing limiter contacts the axially upward sealing surface.
11. A spark plug assembly, comprising: A spark plug, the spark plug comprising a rotating body defining a longitudinal axis, a radial direction, and a circumferential direction, and further comprising: The front axial portion includes an external thread, an intermediate axial collar portion defining an axially downward sealing surface, and a first electrode and a second electrode extending from and defining a spark gap therebetween; and A washer, the washer being axially disposed between the axially downward sealing surface and the external thread of the front axial portion; The spark plug further includes a gasket crushing limiter, which includes a wall extending radially outward and axially downward from the intermediate axial collar portion, thereby defining an annular recess having a radially outer recessed surface that at least partially radially surrounds the gasket.
12. The spark plug assembly of claim 11, wherein the annular recess defines an axial depth and a radial width in a plane including the longitudinal axis and the radial direction, the radial width being greater than the axial depth.
13. The spark plug assembly of claim 12, wherein the washer defines a washerless height measured along the longitudinal axis, the washerless height being greater than the axial depth, and the ratio of the difference between the washerless height and the axial depth to the washerless height is in the range of 20% to 50%.
14. The spark plug assembly of claim 13, wherein the ratio is in the range of 25% to 35%.
15. The spark plug assembly of claim 11, wherein the gasket defines a minimum gasket wall thickness, and the wall of the gasket crushing limiter defines a radial wall thickness greater than the minimum gasket wall thickness.
16. A spark plug comprising: A rotating body, defining a longitudinal axis, a radial direction, and a circumferential direction, and further comprising: The front axial portion includes an external thread, an intermediate axial collar portion defining an axially downward sealing surface, and a first electrode and a second electrode extending from and defining a spark gap therebetween; and A hexagonal drive section, wherein the hexagonal drive section is axially positioned above the intermediate axial collar section; The spark plug further includes a washer crushing limiter, which includes a wall extending axially downward from the intermediate axial collar portion, defining an annular recess formed by the wall and the front axial portion.
17. The spark plug of claim 16, further comprising a transition surface extending axially downward and radially outward from the intermediate axial collar portion to the wall.
18. The spark plug of claim 17, wherein the transition surface is conical.
19. The spark plug of claim 18, wherein the annular recess is defined by a planar axially downward sealing surface, an outer peripheral surface extending from the axially downward sealing surface and being cylindrical, and an inner peripheral surface extending from the axially downward sealing surface and being conical.
20. The spark plug of claim 19, wherein the wall of the gasket crushing limiter terminates in a plane perpendicular to the longitudinal axis, and the inner peripheral surface terminates in the same plane perpendicular to the longitudinal axis.