JPH031474A - Ignition plug - Google Patents
Ignition plugInfo
- Publication number
- JPH031474A JPH031474A JP13563589A JP13563589A JPH031474A JP H031474 A JPH031474 A JP H031474A JP 13563589 A JP13563589 A JP 13563589A JP 13563589 A JP13563589 A JP 13563589A JP H031474 A JPH031474 A JP H031474A
- Authority
- JP
- Japan
- Prior art keywords
- sleeve
- insulator
- nitride
- thermal conductivity
- metal shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 150000004767 nitrides Chemical class 0.000 claims abstract description 11
- 230000004323 axial length Effects 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 3
- 239000012212 insulator Substances 0.000 claims description 24
- 229910052751 metal Inorganic materials 0.000 claims description 24
- 239000002184 metal Substances 0.000 claims description 24
- 229910010293 ceramic material Inorganic materials 0.000 claims description 2
- 238000009413 insulation Methods 0.000 abstract description 10
- 239000000919 ceramic Substances 0.000 abstract description 7
- 239000000126 substance Substances 0.000 abstract 3
- 230000015556 catabolic process Effects 0.000 description 19
- 230000015572 biosynthetic process Effects 0.000 description 11
- 230000007423 decrease Effects 0.000 description 8
- 230000006866 deterioration Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000005684 electric field Effects 0.000 description 4
- 230000017525 heat dissipation Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、点火栓のトリーイング劣化の対策に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to measures against treeing deterioration of spark plugs.
［従来の技術〕 窒化物系セラミクスは、大変優れた熱伝導性を有する。[Conventional technology] Nitride ceramics have very good thermal conductivity.
このため、点火栓の絶縁体に、窒化アルミニウムなどの
窒化物系セラミクスを用いると、点火栓のワイドレンジ
化が図られることが知られている。For this reason, it is known that if nitride ceramics such as aluminum nitride are used as the insulator of the ignition plug, the range of the ignition plug can be expanded.
［発明が解決しようとする課題］
しかるに、窒化物系セラミクスは、従来絶縁体に用いら
れてきたアルミナ等に比較して、温度が高温となった際
の、抵抗値の低下度合いが大きい。[Problems to be Solved by the Invention] However, compared to alumina and the like that have been conventionally used as insulators, nitride-based ceramics have a greater degree of decrease in resistance value when the temperature becomes high.
一方、第３図に示すように、絶縁体１０１は、絶縁体１
０１の周囲に形成された段１０２が、主体金具１０３の
内周に形成された棚１０４に当接Ｌ、軸方向の移動が規
制されている。主体金具１０３の内周は、棚１０４を形
成するために、内周に突出した棚部１０５が形成されて
いる。棚部１０５は、主体金具１０３の内周に突出した
形状であるため、中心電極に高電圧が印加された際に、
棚部１０５と、棚部１０５に対向する脚長部１０６との
間（図中斜線部分）に電界の集中が発生しやすい。On the other hand, as shown in FIG.
A step 102 formed around the metal shell 103 contacts a shelf 104 formed on the inner periphery of the metal shell 103, thereby restricting movement in the axial direction. A shelf portion 105 is formed on the inner periphery of the metal shell 103 to form a shelf 104 that protrudes from the inner periphery. Since the shelf portion 105 has a shape that protrudes from the inner periphery of the metal shell 103, when a high voltage is applied to the center electrode,
Electric field concentration tends to occur between the shelf portion 105 and the long leg portion 106 facing the shelf portion 105 (the shaded area in the figure).
このため、脚長部１０６の温度が高く、脚長部１０６の
絶縁性能が低下した状態で、中心電極に高電圧が印加さ
れると、棚部１０５付近における電界の集中によって、
脚長部１０６の表面にコロナ放電が発生Ｌ、脚長部１０
６の表面に絶縁破壊経路Ａが形成される（トリーイング
劣化）、この絶縁破壊経路Ａが形成されると、点火ミス
が起こるとともに、絶縁破壊経路Ａが成長して、ついに
は、絶縁体１０１の絶縁抵抗が低下Ｌ、失火に至る。Therefore, when a high voltage is applied to the center electrode while the temperature of the long leg portion 106 is high and the insulation performance of the long leg portion 106 is reduced, the concentration of the electric field near the shelf portion 105 causes
Corona discharge occurs on the surface of the long leg portion 106 L, the long leg portion 10
A dielectric breakdown path A is formed on the surface of the insulator 101 (treeing deterioration). When this dielectric breakdown path A is formed, an ignition error occurs and the dielectric breakdown path A grows, and finally, the insulation breakdown path A grows. Insulation resistance decreases L, leading to misfire.
本発明は、上記事情に鑑みてなされたもので、その目的
は、絶縁破壊経路の発生を抑えて点火ミスを無くすとと
もに、絶縁破壊経路の発生による絶縁体の絶縁抵抗の低
下を防ぐ点火栓の提供にある。The present invention has been made in view of the above circumstances, and its purpose is to suppress the occurrence of dielectric breakdown paths to eliminate ignition errors, and to prevent the decrease in insulation resistance of the insulator due to the occurrence of dielectric breakdown paths. On offer.
［課題を解決するための手段］
上記の目的を達成するために、本発明の点火栓は、次の
技術的手段を採用する。[Means for Solving the Problems] In order to achieve the above object, the spark plug of the present invention employs the following technical means.
（発明）
本発明の点火栓は、中心電極と、内周に棚を備えた筒状
の主体金具と、前記棚に当接する段を備えるとともに、
この段を介して小径とされ、前記主体金具との間に空隙
を隔てて対向する脚長部を備えた絶縁体とからなり、前
記絶縁体が窒化物系セラミクス材料よりなる。(Invention) The ignition plug of the present invention includes a center electrode, a cylindrical metal shell with a shelf on the inner periphery, and a step that comes into contact with the shelf, and
The insulator is made of a nitride-based ceramic material and has a small diameter through this step and has a long leg portion facing the metal shell with a gap therebetween.
そして、前記絶縁体は、熱伝導率が６０Ｗ ／ ｍ Ｋ
以上の材料よりなるとともに、前記段より開放端へ向か
う、前記脚長部との間に隙間を有した筒状の絶縁性スリ
ーブを備える。The insulator has a thermal conductivity of 60W/mK.
A cylindrical insulating sleeve made of the above-mentioned material and having a gap with the leg length extending from the step toward the open end is provided.
（実施態様）
前記スリーブの軸方向長をＬ、前記スリーブの前記段側
端部から開放端までの前記主体金具の軸方向長をＬＯと
すると、
ｌａｗ≦Ｌ≦１．０＋１ｍｍ
の式を満足する。(Embodiment) When the axial length of the sleeve is L, and the axial length of the metal shell from the step side end of the sleeve to the open end is LO, the following formula is satisfied: law≦L≦1.0+1 mm .
［作用および効果］
（発明に対応した作用）
上記のように構成された点火栓は、脚長部の温度上昇に
より脚長部の抵抗値が低下しても、スリーブによって、
少なくとも段近傍の脚長部と主体金具との間の絶縁性が
保持される。[Operations and Effects] (Operations Corresponding to the Invention) The ignition plug configured as described above has the effect that even if the resistance value of the long leg portion decreases due to a rise in the temperature of the long leg portion, the sleeve
Insulation is maintained at least between the long leg portion near the stage and the metal shell.
この結果、脚長部の棚近傍における電界の集中が緩和さ
れ、絶縁破壊経路の形成が防がれる。As a result, the concentration of the electric field near the shelf of the long leg portion is alleviated, and the formation of a dielectric breakdown path is prevented.
なお、絶縁体の熱伝導率が６０Ｗ／ｍＫ未満の場合は、
放熱速度が低下Ｌ、プレイグニツシヨンが発生するが、
絶縁体の熱伝導率を６０Ｗ／ｍＫ以上とすることにより
、脚長部の周囲にスリーブを設けても、プレイグニツシ
ヨンの発生を抑えることができる。In addition, if the thermal conductivity of the insulator is less than 60W/mK,
The heat dissipation rate decreases and pre-ignition occurs, but
By setting the thermal conductivity of the insulator to 60 W/mK or more, it is possible to suppress the occurrence of pre-ignition even if a sleeve is provided around the long leg portion.
（発明の効果）
本発明は、以上の作用で説明したように、脚長部の温度
が１−昇しても、絶縁破壊経路の形成が防がれる。この
結果、絶縁破壊経路の形成による点火ミスを無くすとと
もに、絶縁破壊経路の形成による絶縁体の絶縁抵抗の低
下を防ぐことができ、失火を防止する。(Effects of the Invention) As described above, the present invention prevents the formation of a dielectric breakdown path even if the temperature of the long leg portion increases by 1-1. As a result, ignition errors due to the formation of a dielectric breakdown path can be eliminated, and a decrease in insulation resistance of the insulator due to the formation of a dielectric breakdown path can be prevented, thereby preventing misfires.
（実施態様の作用）
スリーブの軸方向長しと、前記スリーブの前記段側端部
から開放端までの前記主体金具の軸方向長ＬＯとの関係
が、１醜≦Ｌ≦Ｌ０＋１ｍｍの式を満足する。(Effects of the Embodiment) The relationship between the axial length of the sleeve and the axial length LO of the metal shell from the step side end of the sleeve to the open end satisfies the following formula: 1mm≦L≦LO+1mm do.
これは、Ｌ ＜ Ｉ Ｗａの関係では、実験的に絶縁破
壊経路がスリーブを回り込んで形成されるためである。This is because in the relationship L < I Wa, a dielectric breakdown path is experimentally formed around the sleeve.
また、Ｌ０＋１ｍｍ＋ｍ＜Ｌの関係では、熱伝導率を６
０Ｗ／ｍＫとしても、放熱速度が劣化Ｌ、プレイグニツ
シヨンが発生するためである。Also, in the relationship L0+1mm+m<L, the thermal conductivity is 6
This is because even at 0 W/mK, the heat dissipation rate deteriorates L and pre-ignition occurs.
（実施態様の効果）
１ｆｉｔＩＩＩ≦Ｌ≦ＬＯ＋１＋ｎｍの式を満足するこ
とにより、スリーブが絶縁破壊経路の形成を防ぐととも
に、プレイグニツシヨンの発生を防ぐことができる。(Effects of the Embodiment) By satisfying the equation 1fitIII≦L≦LO+1+nm, the sleeve can prevent the formation of a dielectric breakdown path and also prevent the occurrence of pre-ignition.
［実施例］
次に、本発明の点火栓を、図に示す一実施例に基づき説
明する。[Example] Next, a spark plug of the present invention will be described based on an example shown in the drawings.
（実施例の構成）
第１図は、内燃機関の燃焼室に配される、点火栓の要部
断面図である。(Configuration of Example) FIG. 1 is a sectional view of a main part of an ignition plug disposed in a combustion chamber of an internal combustion engine.
点火栓１は、大別して、中心電極２、主体金具３、絶縁
体４から構成される。The ignition plug 1 is roughly composed of a center electrode 2, a metal shell 3, and an insulator 4.
中心電極２は、図示しない点火装置から高電圧が印加さ
れる絶縁体４の軸芯を貫通する電極体である。The center electrode 2 is an electrode body that passes through the axis of an insulator 4 to which a high voltage is applied from an ignition device (not shown).
主体金具３は、内燃機関（図示しない）に螺合される筒
状の金具で、端部に、外側電極５が溶接などによって接
合されている。この外側電極５は、棒状を呈Ｌ、端部が
中心電極２との間に火花間隙ｐを介して対向するように
、曲折されている。The metal shell 3 is a cylindrical metal fitting that is screwed into an internal combustion engine (not shown), and an outer electrode 5 is joined to the end by welding or the like. The outer electrode 5 has a rod-like shape L and is bent so that its end faces the center electrode 2 with a spark gap p in between.
一方、主体金具３は、内周に、絶縁体４の段６（下達す
る）が、金属パツキン７を介して当接する棚８を備える
。この棚８は、絶縁体４の保持を行うためのものである
。On the other hand, the metal shell 3 includes a shelf 8 on its inner periphery, with which the step 6 (downward) of the insulator 4 comes into contact with a metal packing 7 interposed therebetween. This shelf 8 is for holding the insulator 4.
絶縁体４は、窒化アルミニウム、窒化珪素などよりなる
熱伝導率が６０Ｗ／ｍＫ以上の窒化物系セラミクスで、
中心電極２の周囲を覆い、中心電極２を絶縁保持する筒
状体を呈する。絶縁体４は、主体金具３との間に空隙を
隔てて対向する脚長部９を備える０脚長部９は、端部に
向かって細くなるテーパー形状を呈する。絶縁体４は、
脚長部９と他の部分との境に段６を有Ｌ、他の部分は、
この段６を介して大径とされている。なお、段６は、主
体金具３の棚８に、金属パツキン７を介して当接Ｌ、軸
方向の移動が規制される。The insulator 4 is a nitride-based ceramic made of aluminum nitride, silicon nitride, etc. and has a thermal conductivity of 60 W/mK or more.
It has a cylindrical body that covers the center electrode 2 and holds the center electrode 2 insulated. The insulator 4 includes a long leg portion 9 that faces the metal shell 3 with a gap therebetween, and the long leg portion 9 has a tapered shape that becomes thinner toward the end. The insulator 4 is
There is a step 6 at the border between the long leg part 9 and other parts, and the other parts are
The diameter is increased through this stage 6. Note that the step 6 abuts L on the shelf 8 of the metal shell 3 via the metal packing 7, and its movement in the axial direction is restricted.
絶縁体４は、脚長部９の周囲に絶縁体４と一体に焼結さ
れた絶縁性のスリーブ１０を備える。このスリーブ１０
は、脚長部９の段６側から開放端へ向かって延びる筒状
体で、脚長部９との間に隙間１１を形成する。The insulator 4 includes an insulating sleeve 10 that is sintered integrally with the insulator 4 around the leg length 9. This sleeve 10
is a cylindrical body extending from the stage 6 side of the long leg portion 9 toward the open end, and forms a gap 11 between the long leg portion 9 and the long leg portion 9 .
スリーブ１０の軸方向長しは、１−以上で、かつスリー
ブ１０の段６側の端部から開放端までの主体金具３の軸
方向長Ｌ０＋１ｍｍ以下に設けられている（つまり、１
ｍ≦Ｌ≦１．０ ＋ １ ｍｍ）。なお、ＬＯ＋１■≦
１０ｍ１である。The axial length of the sleeve 10 is 1 - or more, and the axial length L0 + 1 mm of the metal shell 3 from the end of the sleeve 10 on the stage 6 side to the open end (that is, 1 mm or less).
m≦L≦1.0 + 1 mm). In addition, LO+1■≦
It is 10m1.
Ｌ＜１−の関係では、脚長部９の高温時、実験的に絶縁
破壊経路がスリーブ１０を回り込んで形成される。また
、ＬＯ＋ １ ｒｒｎ＜ Ｌ （ただしＩ、Ｏ＋１閣≦
１０ｍ）の関係では、熱伝導率を６０Ｗ／ｍＫとしても
、絶縁体４の放熱が追い付かず、耐プレイグニッション
が劣化する。このため、ＩＩ＋ａＩＩ≦Ｌ≦１．Ｏ＋１
＋ａの式を満足することにより、スリーブ１０が絶縁破
壊経路の形成を防ぐとともに、プレイグニツシヨンの発
生を防ぐ。In the relationship L<1-, when the long leg portion 9 is at a high temperature, a dielectric breakdown path is experimentally formed around the sleeve 10. Also, LO+ 1 rrn< L (However, I, O+1 kaku≦
10 m), even if the thermal conductivity is 60 W/mK, the heat dissipation of the insulator 4 cannot keep up, and the pre-ignition resistance deteriorates. Therefore, II+aII≦L≦1. O+1
By satisfying the formula +a, the sleeve 10 prevents the formation of a dielectric breakdown path and also prevents pre-ignition from occurring.
なお、実施例では、Ｌ＝ＬＯ／２とした。In addition, in the example, L=LO/2.
（実験データ）
上記実施例の点火栓１のトリーイング劣化に対する実験
データを、第２図に示す。(Experimental Data) Experimental data regarding treeing deterioration of the spark plug 1 of the above example is shown in FIG.
図中に示す比較品とは、脚長部の周囲にスリーブ１０を
有しない従来品で、実施例の点火栓１と同一の熱価のも
のである。The comparative product shown in the figure is a conventional product that does not have the sleeve 10 around the long leg portion, and has the same heat value as the ignition plug 1 of the example.
なお、本実験データは、２０００ｃｃの６気筒エンジン
を使用した。そして、５５００ｒｐｍ（フルスロットル
）を５分間運転した後に、１分間に５回の加減速を実施
するテストを１サイクルとＬ、このテストサイクルを繰
り返し行った。また、中心電極２への印加電圧は、最大
２５ｋＶとした。Note that this experimental data used a 2000cc 6-cylinder engine. After operating at 5500 rpm (full throttle) for 5 minutes, this test cycle was repeated for 1 cycle and L, in which a test was performed in which acceleration and deceleration were performed 5 times per minute. Further, the voltage applied to the center electrode 2 was set to a maximum of 25 kV.
そして、火花間隙ｐで正規の火花放電が起こらない（点
火ミスを発生する）状態となった時に、トリーイング劣
化を判断Ｌ、図中にΔ印で示した。When a normal spark discharge does not occur in the spark gap p (ignition error occurs), treeing deterioration is judged L and is indicated by a Δ mark in the figure.
なお、図中○印は、５０００サイクル行っても、トリー
イング劣化の確認されなかったものを示す。Note that the circle mark in the figure indicates that no treeing deterioration was observed even after 5000 cycles.
（実施例の作用）
点火栓１が過酷な使用条件で使用され、脚長部９の温度
が上昇すると、窒化物系セラミクス（ＡｊＮ）で形成さ
れた脚長部９の絶縁抵抗値が減少する。しかるに、段６
側の脚長部つと主体金具３との間は、スリーブ１０によ
って、絶縁状態が保持される。このため、棚６の近傍に
おける、主体金具３と脚長部９との間の電界の集中が緩
和される。(Effects of the Embodiment) When the spark plug 1 is used under harsh conditions and the temperature of the long leg portion 9 increases, the insulation resistance value of the long leg portion 9 formed of nitride ceramics (AjN) decreases. However, step 6
An insulating state is maintained between the side long leg portions and the metal shell 3 by the sleeve 10. Therefore, concentration of the electric field between the metal shell 3 and the long leg portions 9 in the vicinity of the shelf 6 is alleviated.
この結果、絶縁体４を窒化物系セラミクスで形成しても
、絶縁破壊経路の形成を抑えることができる。As a result, even if the insulator 4 is formed of nitride-based ceramics, the formation of dielectric breakdown paths can be suppressed.
（実施例の効果）
第２図に示されるように、比較品は、約１２００〜２０
００サイクルの間でトリーイング劣化が発生するのに対
Ｌ、本実施例の点火栓１は、４５００サイクルまで、ト
リーイング劣化の発生を抑える。つまり、従来品に比較
して、飛躍的に絶縁破壊経路の形成を抑えることができ
る。(Effects of Example) As shown in Figure 2, the comparative product has a
Whereas treeing deterioration occurs during 00 cycles, the spark plug 1 of this embodiment suppresses the occurrence of treeing deterioration up to 4500 cycles. In other words, compared to conventional products, the formation of dielectric breakdown paths can be dramatically suppressed.
このことは、通常の内燃機関の使用状態において、絶縁
破壊経路の形成をほぼ無くすことが可能となる。この結
果、絶縁破壊経路の形成による点火ミスを無くすととも
に、絶縁破壊経路の形成による絶縁体４の絶縁抵抗の低
下を防ぎ、失火を防止Ｌ、ワイドレンジ化を達成するこ
とができる。This makes it possible to substantially eliminate the formation of dielectric breakdown paths under normal internal combustion engine operating conditions. As a result, it is possible to eliminate ignition errors due to the formation of a dielectric breakdown path, prevent a decrease in the insulation resistance of the insulator 4 due to the formation of a dielectric breakdown path, prevent misfires, and achieve a wide range.
図は実験データを示すグラフ、 大検の要部断面図である。The figure is a graph showing experimental data, It is a sectional view of the main part of the major examination.
図中 １・・・点火栓 ３・・・主体金具 ６・・・段 ９・・・脚長部 １１・・・隙間In the diagram 1... Spark plug 3...Main metal fittings 6th stage 9...Leg length 11... Gap
Claims (1)
小径とされ、前記主体金具との間に空隙を隔てて対向す
る脚長部を備えた絶縁体とからなり、 前記絶縁体が窒化物系セラミクス材料よりなる点火栓に
おいて、 前記絶縁体は、 熱伝導率が６０Ｗ／ｍＫ以上の材料よりなるとともに、 前記段より開放端へ向かう、前記脚長部との間に隙間を
有した筒状の絶縁性スリーブを備えることを特徴とする
点火栓。 ２）前記スリーブの軸方向長をＬ、 前記スリーブの前記段側端部から開放端までの前記主体
金具の軸方向長をＬ０とすると、１ｍｍ≦Ｌ≦Ｌ０＋１
ｍｍ の式を満足する、請求項１記載の点火栓。[Scope of Claims] 1) A center electrode, a cylindrical metal shell with a shelf on its inner periphery, and a step that abuts the shelf, and a small diameter through this step, which connects the metal shell with the center electrode. and an insulator having long legs facing each other with a gap in between, the insulator being made of a nitride-based ceramic material, wherein the insulator is made of a material with a thermal conductivity of 60 W/mK or more. An ignition plug characterized in that the ignition plug includes a cylindrical insulating sleeve that extends from the step toward the open end and has a gap between it and the long leg portion. 2) If the axial length of the sleeve is L, and the axial length of the metal shell from the step side end of the sleeve to the open end is L0, then 1 mm≦L≦L0+1.
The spark plug according to claim 1, which satisfies the formula: mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13563589A JPH031474A (en) | 1989-05-29 | 1989-05-29 | Ignition plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13563589A JPH031474A (en) | 1989-05-29 | 1989-05-29 | Ignition plug |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH031474A true JPH031474A (en) | 1991-01-08 |
Family
ID=15156420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13563589A Pending JPH031474A (en) | 1989-05-29 | 1989-05-29 | Ignition plug |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH031474A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006310129A (en) * | 2005-04-28 | 2006-11-09 | Denso Corp | Device and method for manufacturing spark plug |
| US7723906B2 (en) | 2006-12-08 | 2010-05-25 | Denso Corporation | Spark plug designed to minimize drop in insulation resistance |
| US20150337793A1 (en) * | 2013-02-11 | 2015-11-26 | Contour Hardening, Inc. | Combustion ignition system |
-
1989
- 1989-05-29 JP JP13563589A patent/JPH031474A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006310129A (en) * | 2005-04-28 | 2006-11-09 | Denso Corp | Device and method for manufacturing spark plug |
| US7723906B2 (en) | 2006-12-08 | 2010-05-25 | Denso Corporation | Spark plug designed to minimize drop in insulation resistance |
| US20150337793A1 (en) * | 2013-02-11 | 2015-11-26 | Contour Hardening, Inc. | Combustion ignition system |
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