Patent Grant
9871351
The present disclosure relates to wire ground electrodes for spark plugs for super flow.
This section provides background information related to the present disclosure which is not necessarily prior art.
Internal combustion engines convert chemical energy of a fuel into kinetic energy through combustion of the fuel within a combustion chamber. The expansion of the combustion gasses typically causes a piston to move linearly in a cylinder of the engine. The piston is coupled to a crankshaft configured to convert the linear motion of the piston into rotation of the crankshaft, though other types of engines, such as rotary or Wankel engines for example, can convert the expansion of the combustion gasses into rotational motion without a piston. The rotational motion of the crank can be used to do work such as provide rotary power to a set of wheels of a vehicle for example, or to rotate a rotor of a generator to produce electricity for example.
Internal combustion engines that use certain fuels, such as gasoline or natural gas engines for example, typically use a spark plug to trigger ignition and combustion of an air-fuel mixture that has been compressed in the combustion chamber by the piston. A spark plug typically includes a center electrode and a ground electrode spaced apart from the center electrode by a predetermined gap. The center electrode is typically connected to an electrical source and the ground electrode is connected to a grounding source. The electrical source is typically configured to create a voltage across the gap sufficient to cause electrical arcing, i.e. a spark, to form between the center electrode and the ground electrode when the piston has compressed the air-fuel mixture in the combustion chamber. The size, location, timing, and duration of the spark are designed to ignite the air-fuel mixture to initiate combustion within the combustion chamber. Complete combustion can be important for increasing fuel efficiency and power, and decreasing emissions.
The grounding electrode of traditional spark plugs is formed from a “J” shaped conductive piece typically having a rectangular cross-section. Traditional grounding electrodes can inhibit the flow of the air-fuel mixture to the gap, which can lead to incomplete or unstable combustion. Furthermore, the combustion can cause the temperature of the typical grounding electrode to rise, which can result in premature ignition of the air-fuel mixture. The typical “J” shaped ground electrode extends and terminates freely beyond the center of the center electrode, such that the arcing does not occur at the terminal end of the “J” shape. This configuration can cause some heat to flow from the point of arcing, toward the terminal end, instead of toward the housing. This can cause heat to build up between the terminal end and the point of arcing, which can result in premature ignition of the air-fuel mixture.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present teachings provide for a spark plug for an internal combustion engine including a housing, an insulator, a first electrode, and a ground electrode. The housing can be configured to be coupled to the internal combustion engine. The insulator can be received in the housing. The first electrode can be received in the housing and can be spaced apart from the housing by the insulator. The ground electrode can have a first end, a second end, and a base portion. The first and second ends can be coupled to the housing for thermal conduction with the housing. At least one of the first and second ends can be coupled to the housing for electrical conduction with the housing. The base portion can be spaced apart from the first electrode to define a spark plug gap between the first electrode and the base portion.
The present teachings further provide for a spark plug for an internal combustion engine including a housing, an insulator, a center electrode, and a ground electrode. The housing can define a central bore and a plurality of threads configured to engage a plurality of mating threads formed in the internal combustion engine to removably couple the housing to the internal combustion engine. The insulator can be received in the central bore. The center electrode can be received in the central bore and can be spaced apart from the housing by the insulator. The ground electrode can be formed of a round wire having a first end, a second end, and a base portion. The first and second ends can be welded to the housing for electrical and thermal conduction with the housing. The base portion can be supported by the first and second ends apart from the center electrode to define a spark plug gap between the center electrode and the base portion.
The present teachings further provide for a method of constructing a spark plug for an internal combustion engine. The method can include shaping a wire into an arcuate shape, welding a first end of the wire to a housing configured to be coupled to the internal combustion engine, welding a second end of the wire to the housing, and inserting a center electrode into a central bore of the housing.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
With reference to
The engine head 14 can be formed of a material that is both electrically and thermally conductive, such as aluminum, steel, or a metallic alloy for example. The engine head 14 can be electrically coupled to a grounding source (not shown), such as a vehicle body or negative terminal of a battery for example. The engine head 14 can define a plug bore 38 having a plurality of interior threads 42. The engine head 14 can define a cooling conduit 46. The cooling conduit 46 can be configured to allow engine coolant fluid to flow through the engine head 14 proximate to the plug bore 38. The cooling conduit 46 can form a “cooling jacket” that can surround the plug bore 38 to provide cooling on all sides of the plug bore 38. The engine coolant can absorb heat from the engine head 14 and release the heat away from the engine 10 at a heat exchanger (not shown), such as a radiator for example, in order to cool the engine head 14 and spark plug 26, as will be described below.
The spark plug 26 can include a housing 50, an insulator 54, a terminal 58, a center electrode 62, and a ground electrode 66. The spark plug 26 can also include a seal 70, and a gasket 74. The center electrode 62 can include a center electrode tip 78 and the ground electrode can include a ground electrode tip 82, as will be described below.
The housing 50 can include a first portion 86 and a second portion 90. The first portion 86 and second portion 90 can be unitarily formed of an electrically and thermally conductive material, such as a steel alloy for example. The housing 50 can define a central bore 94 that extends through the first and second portions 86, 90 along a central axis 98. The central bore 94 can vary in diameter along the length of the housing 50. In the example provided, the central bore 94 is narrowest proximate to a first end 102 of the housing at the first portion 86, and expands in a generally step-wise manner toward a second end 106 of the housing 50 at the second portion 90, though other configurations can be used. In the example provided, the central bore 94 includes a narrowest or first diameter section 110, an intermediate or second diameter section 114, and a wider or third diameter section 118, with ramped steps 122, 126 between each section 110, 114, 118, though other configurations can be used. The first diameter section 110 can be wholly within the first portion 86, the second diameter section 114 can span between the first and second portions 86, 90, and the third diameter section 118 can be wholly within the second portion 90, though other configurations can be used.
An outer diameter 130 of the first portion 86 can include a plurality of exterior threads 134 configured to matingly engage with the plurality of interior threads 42 of the plug bore 38 of the engine head 14. In this way, the first portion 86 can be screwed into the engine head 14 and be enveloped by the engine head 14. Contact between the outer diameter 130 of the first portion 86 and the engine head 14, and between the interior and exterior threads 42, 134 can allow for electrical and thermal conductivity between the housing 50 and the engine head 14.
An outer diameter 138 of the second portion 90 can be greater than the plug bore 38. The gasket 74 can be a ring shape with an inner diameter 142 greater than the outer diameter 130 of the first portion 86 and less than the outer diameter 138 of the second portion 90, and can be disposed about the first portion 86 proximate to the second portion 90 such that screwing the first portion 86 into the engine head 14 can cause the second portion 90 to compress the gasket 74 against the engine head 14 to form a seal therebetween. The outer diameter 138 of the second portion 90 can also define a tool surface 146, such as a hexagonal shape for example, configured to permit a tool (not shown) to grip the housing 50 to screw the housing 50 into the engine head 14. The second portion 90 can also include a flange 150 proximate to the second end 106 and configured to intrude radially into the central bore 94 to retain the insulator 54 within the central bore 94, as will be discussed below.
The insulator 54 can be formed of an electrically insulating and thermally conductive material, such as a high purity alumina material for example. The insulator 54 can have an interior portion 154 and an exterior portion 158 and can define an insulator bore 162 extending through the length of the insulator 54 along the axis 98. The interior and exterior portions 154, 158 can be unitarily formed of a single piece of material. An outer surface 166 of the interior portion 154 can generally contour with the varying diameter sections 110, 114, 118 and ramped steps 122, 126 of the central bore 94 of the housing 50. A first end 170 of the interior portion 154 can extend axially beyond the first end 102 of the housing 50, such that the first end 170 of the insulator 54 can extend into the combustion chamber 34 when the spark plug 26 is fully screwed into the engine head 14. The exterior portion 158 can be narrower than the third diameter section 118 of the housing 50 and a second end 174 of the exterior portion 158 can extend axially beyond the second end 106 of the housing 50. The flange 150 can protrude radially inward at the junction of the interior and exterior portions 154, 158 to retain the insulator 54 within the housing 50.
The terminal 58 can be formed of an electrically conductive material, such as a steel alloy for example. The terminal 58 can have a terminal stud 178 and a terminal head 182. The terminal stud 178 can be generally cylindrically shaped and can be received in the insulator bore 162. The terminal stud 178 can extend through the exterior portion 158 of the insulator 54 and into the interior portion 154 of the insulator 54, though other configurations can be used. The terminal head 182 can be generally bulb-shaped and extend axially beyond the second end 174 of the exterior portion 158 of the insulator 54. The terminal head 182 can be configured to accept and retain a high-tension cord (not shown) through which high-voltage current from an ignition system (not shown) of the engine 10 can flow to the terminal 58. While not specifically shown, the terminal head 182 can also include a terminal nut.
The seal 70 can be formed of a material configured to bond to the terminal stud 178 and the insulator 54, such as a material formed from a mixture of glass powder and copper powder for example. The seal 70 can be disposed radially between the terminal stud 178 and the insulator bore 162 and can form a seal therebetween. In the example provided, the seal 70 is disposed between the terminal stud 178 and the interior portion 154 of the insulator 54 within the second portion 90 of the housing 50, though other configurations can be used. In the example provided, the terminal stud 178 is coupled to the center electrode 62 at a portion of the insulator bore 162 sealed by the seal 70. The terminal stud 178 can transfer high-voltage current from the terminal head 182 to the center electrode 62.
The center electrode 62 can be formed of an electrically conductive material. In the example provided, the center electrode 62 has an outer shell 186 that is formed of a nickel alloy material, and has an inner core 190 formed of a copper material, though other configurations or materials can be used. The center electrode 62 can be received in the insulator bore 162 and can extend axially from within the first portion 86 of the housing 50, to beyond the first end 102 of the housing 50 and beyond the first end 170 of the insulator 54. In this way, the center electrode 62 can extend into the combustion chamber 34 when the spark plug 26 is fully screwed into the engine head 14. The center electrode 62 can also include the center electrode tip 78. The center electrode tip 78 can be formed of a precious metal material, such as iridium or platinum for example. In the example provided, the center electrode tip 78 is welded to the outer shell 186 of the center electrode 62 axially beyond the insulator 54.
With additional reference to
The ground electrode 66 can include an outer wire 226 surrounding a core wire 230. The ground electrode 66 can also include the ground electrode tip 82. The outer wire 226 can be an alloy configured for withstanding high temperatures, such as an alloy including nickel, chrome, and/or platinum for example, though other alloys can be used. The core wire 230 can be a highly thermally conductive material, such as copper for example. The core wire 230 can extend the entire length of the ground electrode 66 from the first ground end 210 to the second ground end 214. The ground electrode tip 82 can be formed of a precious metal, such as iridium or platinum for example. In the example provided, the ground electrode tip 82 is welded to the base 222 of the “U” shape of the ground electrode 66, such that the ground electrode tip is centered on the axis 98 or aligned with the center electrode tip 78 and axially spaced apart from the center electrode tip 78 to define a gap 238. The gap 238 can be configured to permit electrical arcing, i.e. a spark, to form between the center electrode tip 78 and the ground electrode tip 82 when high-voltage current is supplied to the center electrode tip 78 from the terminal 58. The gap 238 can be the closest distance between the ground electrode 66 and the center electrode 62 such that arcing is prevented from occurring at other locations along the ground electrode 66. The ground electrode tip 82 can be a different diameter than the center electrode tip 78, depending on the application.
The “U” shaped ground electrode 66 can allow heat from the combustion to travel in two, opposite directions 242, 246 from the single ground electrode tip 82, into the housing 50, where the heat can then be transferred into the engine head 14 (
Furthermore, unlike traditional spark plug ground electrodes (not shown), since both ground ends 210, 214 are welded to the housing 50, the core wire 230 does not need to terminate within the outer wire 226 to prevent corrosion of the core wire 230 at the free end of the traditional ground electrode. Instead, the core wire 230 can extend throughout the entire length of the outer wire 226. In this way, the core wire 230 and outer wire 226 can contact the housing 50 in two distinct locations, on diametrically opposite sides of the housing 50 to allow more heat to transfer away from the ground electrode tip 82 than in traditional ground electrodes. In other words, a heat quenching effect of the ground electrode 66 is increased over traditional ground electrodes, which can result in a reduced chance of pre-ignition. This configuration also allows for the ground electrode 66 to be cut from a continuous wire of material, which can decrease manufacturing complexity, as will be discussed below.
With additional reference to
With reference to
The wire blank 610 can be positioned in a first die 618 having a curved relief surface 622. A first press 626 can have a mating curved surface 630 and can be moved in the direction 634 to be received into the first die 618 to press the wire blank 610 between the first die 618 and the first press 626. The operation of pressing the wire blank 610 between the curved relief surface 622 of the first die 618 and the mating curved surface 630 of the first press 626 can shape the wire blank 610 into the curved shape of the ground electrode 66, as shown in
With specific reference to
After welding the ground electrode 66 to the housing 50, the ground electrode 66 can be positioned on a second die 710 and a second press 714 can be configured to move in the direction 718 to press a flat surface 722 (
With specific reference to
In summary, the construction of the ground electrode 66 according to the present teachings can reduce cost and ease manufacturing by allowing the ground electrode 66 to be cut and formed from the wire 614 without the need to terminate the core wire 230 within the outer wire 226. The ground electrode 66 can also increase the heat quenching effect by providing two paths in opposite directions for heat to dissipate away from the ground electrode tip 82. The ground electrode 66 can also improve ignition of the air-fuel mixture 410 by reducing the area of stagnation 450 of the air-fuel mixture 410 and improving flow of the air-fuel mixture 410 to the gap 238 where arcing occurs.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
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| Number | Date | Country | |
|---|---|---|---|
| 20160156158 A1 | Jun 2016 | US |
