Patent Grant
11002219
The present disclosure relates generally to spark plugs and gaskets/seals that are used in internal combustion engines to prevent gases from blowing out of the combustion chamber through a gap located between the spark plug and the cylinder head of the engine. More specifically, the present disclosure relates to a spark plug having a feature that limits the amount of compression exerted on the gasket/seal.
Internal combustion engines are routinely used in various industries to power machines and equipment. Examples of industries using such machines and equipment include marine, earth moving, construction, mining, locomotive and agriculture industries, etc. Some of these engines employ spark plugs that have gaskets or seals interposed between the spark plug and the spark plug bore in the cylinder head. These seals or gaskets help to prevent gases that are highly pressured from escaping the combustion chamber through the spark plug bore (sometimes referred to as “blow by”). From time to time, these spark plugs are unscrewed from the cylinder head for maintenance purposes. Then, a new or refurbished spark plug is provided by screwing the spark plug so that its external threads mate with the internal threads of the spark plug bore.
More specifically, a mechanic or the like may use a wrench or a socket to engage the hex portion of the spark plug to tighten it properly. However, over torqueing the spark plug can lead to the spark plug pressing on the seal/gasket via its seal engaging surface too much. In technical parlance, this may be referred to as “crushing” the seal and gasket. If the deformation is permanent (plastic), this may remove the requisite elasticity from the gasket/seal that is necessary to prevent the “blow by”. This may lead to poor performance and thus undesirable additional maintenance.
U.S. Pat. No. 9,787,063 to Niessner discloses a sealing ring for a spark plug that has an external thread for screwing into an internal combustion engine, a collar, and thread undercut between the external thread and the collar. The sealing ring include a ring-shaped solid sealing element made from metal. The sealing element has two planar annular sealing surfaces that are arranged parallel to one another. An annular retaining element composed of an elastomer for engaging in the thread undercut of the spark plug in a self-retaining manner is attached to the sealing element on the inner ring side thereof. Also, there is a spark plug comprising such a sealing ring, and an internal combustion engine comprising such spark plugs.
An internal combustion engine according to an embodiment of the present disclosure may comprise a cylinder head that includes a flame deck surface that at least partially defines a combustion chamber, a spark plug receiving bore that defines a longitudinal axis, a radial direction, and a circumferential direction, and that includes an enlarged diameter portion including an axially upwardly facing sealing surface, and a reduced diameter portion including internal threads. The engine may further comprise a spark plug including a forward axial portion including external threads meshing with internal threads of the reduced diameter portion of the spark plug receiving bore, and an intermediate axial collar portion defining an axially downwardly facing sealing surface. A gasket may be disposed axially between the axially upwardly facing sealing surface of the spark plug receiving bore, and the axially downwardly facing sealing surface of the spark plug. The spark plug may further comprise a gasket crush limiter including a wall that extends radially outwardly and axially downwardly from the intermediate axial collar portion toward the axially upwardly facing sealing surface of the spark plug receiving bore, radially surrounding the gasket.
A spark plug assembly according to an embodiment of the present disclosure may comprise a spark plug including a body of revolution defining a longitudinal axis, a radial direction, and a circumferential direction. The spark plug may further include a forward axial portion including external threads, an intermediate axial collar portion defining an axially downwardly facing sealing surface, and a first electrode and a second electrode extending from the forward axial portion, defining a spark gap therebetween. A gasket may be disposed axially between the axially downwardly facing sealing surface, and the external threads of the forward axial portion. The spark plug further comprises a gasket crush limiter including a wall that extends radially outwardly and axially downwardly from the intermediate axial collar portion, defining an annular pocket with a radially outer pocket wall that at least partially surrounds the gasket radially.
A spark plug according to an embodiment of the present disclosure may comprise a body of revolution defining a longitudinal axis, a radial direction, and a circumferential direction. The spark plug may further include a forward axial portion including external threads, an intermediate axial collar portion defining an axially downwardly facing sealing surface, and a first electrode and a second electrode extending from the forward axial portion and defining a spark gap therebetween. A hex drive portion may be disposed axially above the intermediate collar portion. The spark plug further comprises a gasket crush limiter including a wall that extends axially downwardly from the intermediate axial collar portion, defining an annular pocket formed by the wall and forward axial portion.
Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In some cases, a reference number will be indicated in this specification and the drawings will show the reference number followed by a letter for example, 100a, 100b or a prime indicator such as 100′, 100″etc. It is to be understood that the use of letters or primes immediately after a reference number indicates that these features are similarly shaped and have similar function as is often the case when geometry is mirrored about a plane of symmetry. For ease of explanation in this specification, letters or primes will often not be included herein but may be shown in the drawings to indicate duplications of features discussed within this written specification.
Various embodiments of a spark plug or a spark plug assembly that may be used in an internal combustion engine according to various embodiments of the present disclosure will now be described. More particularly, the spark plug or spark plug assembly may include a gasket crushing limiter that will be described in detail.
For example, an internal combustion engine 100 is shown in
More specifically, the engine 100 includes a cylinder head 104 having a flame deck surface 110 that at least partially defines a combustion chamber 106. The spark plug assembly 200 or spark plug 300 extends past this surface 110 into the combustion chamber 106 to ignite the fuel/air mixture during operation of the engine 100.
The cylinder head 104 has a spark plug receiving bore 112 that defines a longitudinal axis 114, a radial direction 116, and a circumferential direction 118. For example, this bore 112 may have a cylindrical or conical shape, etc. Consequently, this bore 112 includes an enlarged diameter portion 120 including an axially upwardly facing sealing surface 122, and a reduced diameter portion 124 including internal threads 126. Portion 124 is disposed axially below portion 120, but not necessarily so.
A spark plug 300 may be disposed in the spark plug receiving bore 112. This spark plug 300 may include a forward axial portion 302 including external threads 304 that mesh with internal threads 126 of the reduced diameter portion 124 of the spark plug receiving bore 112 (see also
As seen in
As best seen in
Once the spark plug 300 is fully installed, the wall 312 of the gasket crush limiter 310 may contact the axially upwardly facing sealing surface 122 of the spark plug receiving bore 112. The wall 312 and the gasket 128 may be so configured such that the gasket cannot be compressed too much. In particular embodiments of the present disclosure, the gasket 128 includes a serpentine shape (i.e. having at least one bend) including straight portions 130 that are spaced at least partially axially away (i.e. parallel to the axis 114) from each other. Put another way in spring terminology, the gasket is not compressed completely to its solid length or solid state.
The gasket may be manufactured from various types of materials including elastomers, rubbers, metal, aluminum, stainless steel, etc. As shown in
As mentioned previously herein, the spark plug 300 may be a subassembly. Accordingly, the wall of the gasket crush limiter 310 could be a separate component that is attached to the spark plug. On the other hand, the wall 312 of the gasket crush limiter 310 may be unitary (i.e. constructed from a single piece) with the intermediate axial collar portion 306 of the spark plug as shown in
Likewise as seen in
It is desirable to separate the cooling fluid from the combustion chamber 106 and its gases, and the spark plug sleeve receiving bore 133, and vice versa. So, a lower axial seal 138 may be disposed between the spark plug sleeve 136, and the cylinder head 104, and while an upper axial seal 140 may be disposed between the spark plug sleeve 136, and the cylinder head 104.
In
Looking at
In addition, at least one of the two electrodes (e.g. ground electrode 320) in
In other words, the relative configuration of the wall, the gasket, and timing of the engagement between the internal and the external threads may be selectively chosen so that a consistent position and orientation of the spark plug and its components as well as the gasket is achieved every time the spark plug is fully tightened. This may not be the case for other embodiments of the present disclosure.
Next, a spark plug assembly 200, 200a that may be provided as a replacement part/assembly according to various embodiments of the present disclosure will be described.
Turning to
The spark plug assembly 200, 200a may be constructed as follows. A gasket as previously described 128 may be retained onto a spark plug 300, 300a in a manner discussed earlier herein (e.g. captivated by a portion of the gasket extending into the external thread undercut). This may ease installation and help prevent damage to the gasket 128 during installation.
The spark plug 300, 300a may include a sleeve-shaped spark plug body 324, 324a made from metal and an elongated insulator 326, 326a made from ceramics. In a more general sense, the body 324, 324a may be characterized as a body of revolution since its geometry is at least partially created by rotating a geometrical cross-section about a longitudinal axis 332, further defining a radial direction 334 and a circumferential direction 336. The insulator 326, 326a may surround an inner conductor 328, 328a which is connected inside the insulator 326, 326a to the center electrode 318 via a glass seal 329a in
Focusing on
The beginning of the first thread turn of the threads is designated as thread start 330, and may have a defined circumferential position/orientation with respect to the ground electrode 320. After screwing into the internal combustion engine, the section of the ground electrode 320 (referred to earlier as the radial extending portion) that runs transverse to the longitudinal axis 332 of the spark plug 300a may then have a predefined angle with respect to the crankshaft (not shown). This may not be the case for other embodiments of the present disclosure.
The spark plug body 324a may also have an intermediate axial collar portion 306, which is arranged on the side of the external threads 304 that faces away from the forward axial portion 302a. A hex drive portion 338 may also be provided that is disposed axially above the intermediate axial collar portion 306.
As alluded to earlier herein with reference to
The annular pocket 338 may define an axial depth 340, and a radial width 342 in a plane containing the longitudinal axis 332 and the radial direction 334 (e.g. the sectioned plane of
In addition, the annular pocket 338 may define a pocket outer diameter 344, and the wall 312 of the gasket crush limiter 310 defines a wall outer diameter 346. In some embodiments, the gasket 128 defines a gasket minimum wall thickness 132 that is less than the radial wall thickness 314 of the wall 312 of the gasket crush limiter 310. Put another way, the radial wall thickness 314 may be greater than the gasket minimum wall thickness 132.
In some embodiments as best seen in
Now, an embodiment of a spark plug 300, 300a that may be supplied as a replacement part/subassembly will now be discussed with continued reference to
The gasket crush limiter 310 may include a wall 312 that extends axially downwardly from the intermediate axial collar portion 306, defining an annular pocket 338 formed by the wall 312 and forward axial portion 302. In such a case, the intermediate axial collar portion 306 may not be flared as shown in
However, in some embodiments of the present disclosure as shown in
Focusing on
In certain embodiments, the wall 312 of the gasket crush limiter 310 terminates at a plane 354 that is 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 the present disclosure.
The configuration and dimensional ranges of any of the embodiments discussed herein may be altered to be different depending on the application.
The spark plug and gasket may be manufactured from any suitable material using any suitable manufacturing process including but not limited to anything specifically, implicitly, or inherently described herein.
In practice, a spark plug, a spark plug assembly, and/or an engine assembly using such a spark plug or spark plug assembly according to any embodiment described herein may be provided, sold, manufactured, and bought etc. as needed or desired in an aftermarket or OEM (original equipment manufacturer) context. For example, a spark plug or a spark plug assembly may be used to retrofit an existing engine already in the field or may be sold with an engine or a piece of equipment using that engine at the first point of sale of the piece of equipment.
Various embodiments may provide for reduced maintenance of the engine due to less damage to the spark plug gasket. Also, proper positioning and/or orientation of the electrodes of the spark plug may be more reliably provided.
Moreover, the disclosed dimensional ranges and/or ratio ranges may provide a critical result not taught in the prior art. Particularly, these variables may allow the wall of the gasket crush limiter take 90% or more of the axial load created when the spark plug is tightened, helping to protect the gasket from being over compressed or crushed. Also, the pocket that receives the gasket and the features defining and/or surrounding the pocket may help to keep the gasket away from the bottom sealing surface of the wall of the limiter so that the gasket does not get pinched, etc. during installation.
It will be appreciated that the foregoing description provides examples of the disclosed assembly and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and methods of assembly as discussed herein without departing from the scope or spirit of the invention(s). Other embodiments of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the equipment may be constructed and function differently than what has been described herein and certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4015161 | Resler, Jr. | Mar 1977 | A |
| 9787063 | Niessner et al. | Oct 2017 | B2 |
| 20090102346 | Fukuzawa | Apr 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| 2642497 | Aug 1990 | FR |
