JPS58135590A - Ignition plug for internal combustion engine - Google Patents

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

【発明の詳細な説明】 本発明は、カーボンなどによるくすぶり時にも飛火して
混合気に着火で龜るとともに、そのカーボンなどの付着
物を焼き切ることのできる内燃機関用点火栓に関するも
のである。゛ 従来この種の点火栓としては、特公昭５８−１０２１９
号公報に記載されたものがある。これは第１図に示す構
造を有しており１通常時には中心電極ｌと第１接地電極
８との間の気中火花ギャップ６で飛火し、絶縁碍子２の
脚ｆｉｌｌ畠にカーボン、オイル、未燃焼燃料の導電性
物質が付着して脚部２亀の絶縁抵抗が低下すると、中心
電極ｌと第８接地電ｊｔＭ＋との間で脚部ｇａの外表面
ならびに脚部２ａと第２接地電極１との間の関１１１５
を経九半沿面火花ギャップ７に飛火し、この火花で上記
導電性物質を焼き切って脚部２ａの絶縁抵抗を回復する
とともに、気中火花ギャップ６への飛火に復帰するよう
にしである。また、ギャップ７での飛火時には混合気に
着火できるようにしである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition plug for an internal combustion engine that is capable of igniting the air-fuel mixture by igniting the air-fuel mixture even when carbon or the like smolders, and can burn off the carbon or other deposits.゛Conventionally, this type of ignition plug was manufactured by the Special Publication Publication No. 58-10219.
There is something described in the No. This has the structure shown in Fig. 1.1 Normally, sparks fly in the air spark gap 6 between the center electrode 1 and the first ground electrode 8, and carbon, oil, etc. When the conductive substance of the unburned fuel adheres and the insulation resistance of the leg 2 tortoise decreases, the outer surface of the leg ga as well as the outer surface of the leg ga and the leg 2a and the second ground electrode are connected between the center electrode l and the eighth ground electrode jtM+. Seki 1115 between 1
The sparks fly into the creeping spark gap 7, and the sparks burn off the conductive material to restore the insulation resistance of the legs 2a, and the sparks return to the air spark gap 6. Furthermore, the air-fuel mixture is designed to ignite when sparks fly in the gap 7.

しかしながら、上記従来公知のものでは、取付餘具３の
端面８ａならびに第２接地電極４の端面４ａＫＩｉ記導
電性物質が付着すると、内燃機関の燃焼藁内の燃焼ガス
、新規混合ガスの図中Ｘ方向の流れに影響されてその導
電性物質が前記間＠ｂ、内に移動し、この九め関１１５
内の一部が短絡（導電性物質によるブリッジ）して前記
半沿面放電ギャップ７への飛火が行なわれにくくなるこ
とが判明した。However, in the above-mentioned conventionally known device, if the conductive material adheres to the end surface 8a of the mounting tool 3 and the end surface 4a of the second grounding electrode 4, the combustion gas in the combustion straw of the internal combustion engine and the new mixed gas (X in the figure) Under the influence of the flow in the direction, the conductive substance moves into the space @b, and this ninth barrier 115
It has been found that a part of the discharge gap 7 is short-circuited (bridged by a conductive material), making it difficult for sparks to spread to the semi-creeping discharge gap 7.

そこで、本発明は上述の点に鑑み、第２接地電極の取付
金具に対する設置位置を特定位置に設定することにより
、上述の不具合を解消しようとするものである。Therefore, in view of the above-mentioned points, the present invention attempts to solve the above-mentioned problems by setting the installation position of the second ground electrode with respect to the mounting bracket at a specific position.

以下本発明を具体的実施例により説明する。第８ＷＪ〜
第４図において、本発明の点火栓は第１ｍの従来公知例
と基本的に同じであるが、第２接地電極４の設置位置が
異なる。The present invention will be explained below using specific examples. 8th WJ~
In FIG. 4, the spark plug of the present invention is basically the same as the 1mth conventional known example, but the installation position of the second ground electrode 4 is different.

即ち、第ｇ１１地電ｆｉ４は取付金具８とともに冷鍛打
抜き法により一体に環状に設けであるが、その設置位置
が取付金具８の端面８ａより内側に位置している。なお
、図中９はパツキン、１０社かしめリング、ｌｉｔ：ｌ
端子を示している。That is, the g11th earth power fi4 is integrally provided in an annular shape with the mounting bracket 8 by cold forging punching, but its installation position is located inside the end surface 8a of the mounting bracket 8. In addition, 9 in the figure is a packing ring, 10 is a caulking ring, lit: l
Shows terminals.

本発明で轄、第４図のごとく、金具８の端面８＆１と第
２接地電極４の金具側付根部の端面４ａとの間の寸法を
島とし、かつ金具８の内面８ｂと第２接地電極鴫の間隙
形成端４ｂとの間の寸法をｂとしたときに、この各寸法
ａ、ｂを所定値に設定したのである。In the present invention, as shown in FIG. 4, the dimension between the end surface 8&1 of the metal fitting 8 and the end surface 4a of the metal fitting side base of the second ground electrode 4 is an island, and the inner surface 8b of the metal fitting 8 and the second ground electrode The dimensions a and b are set to predetermined values, where b is the dimension between the gap forming end 4b and the gap forming end 4b.

次に、上記ａ、ｂの寸法値によって前述の「導電性物質
によるブリッジ」の発生具合がどのように変化するかを
実験により求めた。今回行った実験について説明すると
、一般的な４サイクル・４ンリンダー・ｌ　８００αの
不漏乗用車を用いて実施した。また試験条件としては、
室温から一１０℃の低温車両室においてアイドリングお
よび軽負侑低連運転（２０ム／Ｈ）を組合せた運転パタ
ーンを４分定行した後、エンジ、ンを停止させ冷却水温
　　　１＋および潤滑油温がふたたび−ｌＯ℃になるま
で放置する（約５０〜６０分間）。これを１サイクルと
し異常がなければ１０１イクル継続し、途中で導電性物
質によるプリフジが発生し始動または走行が不可能にな
った場合はその時点で中止をする０なお、点火栓の仕様
としては第１接地電極８と中心電１ｍｌとの気中火花ギ
ヤ？プロｔｆｌ、０〜１．１１１１の間とし、絶縁碍子
２は取付金具８の端面８畠より燃焼室側へ１，０■突出
しているものとした。さらに、絶縁碍子２と第２接地電
極４との間によって形成される円環状の間ＩＩＳはｏ、
４ｍ（導電物質によるブリッジが発生し易い傾向にある
寸法）とした。この点火栓において第４図に示す１寸法
。Next, it was determined through experiments how the degree of occurrence of the above-mentioned "bridge caused by the conductive material" changes depending on the dimension values of a and b. To explain the experiment conducted this time, it was carried out using a general 4-stroke, 4-liner, 800α leak-proof passenger car. In addition, the test conditions are as follows:
After running a driving pattern that combines idling and light load continuous operation (20 m/h) for 4 minutes in a low-temperature vehicle compartment of -10°C from room temperature, the engine was stopped and the cooling water temperature was 1+ and the lubricating oil temperature. Leave until the temperature is -10°C again (approximately 50-60 minutes). This is regarded as one cycle and continues for 101 cycles if there are no abnormalities. If pre-fugitive occurs due to conductive material and it becomes impossible to start or run, stop at that point. Air spark gear between the first grounding electrode 8 and the central electrode 1ml? The insulator 2 was assumed to protrude 1.0 mm from the end face 8 of the mounting bracket 8 toward the combustion chamber side. Furthermore, the annular gap IIS formed between the insulator 2 and the second ground electrode 4 is o,
The length was set at 4 m (a dimension that tends to cause bridging due to conductive substances). In this spark plug, one dimension shown in FIG.

５寸法を第ｂｖ７１ｉに示すように変化させて前述の実
験条件にて実施した。The experiment was conducted under the above-mentioned experimental conditions while changing the 5th dimension as shown in bv71i.

第５図に示す結果について説明すると、１寸法がＯ０ｇ
閣の場合Ｕｔた効果があられれていないが、それ以上の
寸法にすると導電物質に−よるブリッジの発生がなくな
ってくる（図中、Ｘ印１）１ａ但し。To explain the results shown in Figure 5, one dimension is O0g
However, if the size is larger than that, the bridging caused by the conductive material will disappear (X mark 1 in the figure).

１寸法を大きくしすぎると、火花位置が取付金具８の内
個？奥深くになるため、新規混合ガスに触れにくくなる
（図中、Δ印）。If one dimension is made too large, will the spark position be within the mounting bracket 8? Because it is deep, it is difficult to come into contact with the new mixed gas (indicated by Δ in the diagram).

次に、５寸法について検討してみると、５寸法が小さい
時（ｂ＝ＯＪ５■）は取付金具８の端面８＆が第２接地
電ｌ１ｊ４の役割をねたずためａ＝０の場合と大差ない
結果が得られた（図中、Ｘ印）。Next, when considering the 5th dimension, when the 5th dimension is small (b = OJ5■), the end face 8& of the mounting bracket 8 plays the role of the second grounding conductor l1j4, so there is a large difference from the case where a = 0. No results were obtained (marked with an X in the figure).

一方、５寸法を大きくとりすぎた場合（ｂ＝１．０關）
、には取付金具８の端面８ａの肉厚が薄くなり、第１接
地電極８を取付金具８へ溶接結合させるときに溶接パリ
の発生、もしくは取付がむづかしくなる（図中、△印）
。On the other hand, if the 5th dimension is set too large (b=1.0)
, the wall thickness of the end surface 8a of the mounting bracket 8 becomes thinner, and when the first ground electrode 8 is welded to the mounting bracket 8, welding cracks occur or installation becomes difficult (indicated by △ in the figure).
.

従って、第５図の結果から明白なごとく、飛火性の点で
ｑａ寸法は０．８■以上、５寸法もｏ、ａｍ以上必要で
あり、望ましくＦｉｍ寸法Ｆｉ０．８調〜２、□ｓ＋＋
＋＋、ｂ寸法は０．３Ｗ〜０．７５鱈がよい。Therefore, as is clear from the results shown in Figure 5, in terms of spark resistance, the qa dimension needs to be at least 0.8 ■, and the 5 dimensions need to be at least o and am, and it is desirable that the Fi dimension is 0.8 to 2, □s++
++, b dimension is preferably 0.3W to 0.75 cod.

なお、本実験において前述したように絶縁碍子２の取付
金具８の端面８ａからの突出し量が１．０■の点火栓に
ついて検討をしたが、この寸法の大小については第５図
の結果にはあまり影響を及ぼさないことがわかった。In this experiment, as mentioned above, we investigated a spark plug in which the amount of protrusion of the mounting bracket 8 of the insulator 2 from the end surface 8a was 1.0 cm, but the results shown in Fig. 5 do not correspond to the size of this dimension. It turns out that it doesn't have much of an effect.

本発明点火栓の作用について説明すれば、次のようであ
る。即ち、気中火花ギャップ６の飛火要求電圧■・と半
沿面火花ギャップの飛火要求電圧ｖ７との関係は、絶縁
碍子８の脚部２ａに前述の導電性物質が付着してない正
常時にはＶ・＜Ｖｙとなり、導電性物質が付着して脚部
２ａの絶縁抵抗が低下したときにはＶ・＜　Ｖ　７とな
るようにしてあり、この関係を満足するように各ギャッ
プ６゜７の寸法値が設定しである（これは特公昭６８−
１０２１９号に一例が示しである）。The function of the spark plug of the present invention will be explained as follows. That is, the relationship between the required spark voltage for the aerial spark gap 6 and the required spark voltage for the semi-creeping spark gap v7 is V. <Vy, and when the conductive substance adheres and the insulation resistance of the leg 2a decreases, V・<V 7. The dimensions of each gap 6°7 are set to satisfy this relationship. (This is a special public service issued in 1988
An example is given in No. 10219).

従って、脚部２畠の絶縁抵抗が低下していない正常時に
は気中火花ギャップ６に飛火する。一方、脚部２ａの絶
縁抵抗が低下したときには半沿面火花ギャップ７に飛火
し、絶縁抵抗低下の原因である前記導電性物質を焼き切
ると同時に間１ｌｌ１５での火花により混合気に着火す
る。との半沿面火花ギャップ７での飛火によって脚部２
ａの絶縁抵抗が正常に回復すると、気中火花ギャップ６
への飛火に復帰する。Therefore, under normal conditions when the insulation resistance of the leg portions 2 is not reduced, sparks fly into the air spark gap 6. On the other hand, when the insulation resistance of the leg portion 2a decreases, sparks fly into the semi-creeping spark gap 7, burn out the conductive material that is the cause of the decrease in insulation resistance, and at the same time ignite the air-fuel mixture by the spark at the gap 11115. leg 2 due to flying sparks in the semi-creeping spark gap 7 between
When the insulation resistance of a returns to normal, the air spark gap 6
Return to flying fire.

本発明では、第４図のａ、ｂの各寸法の設定により、第
２接地電極４が取付金具８の端面８ａよりその内方へ位
置するため、導電性物質が第２接接地電極会の端面４＆
に付着しに〈〈なり、また取付金具８の端面８ａから間
隙すまでの間の距離が長くなるので、第４図中×゛方向
から流れる燃焼ガス、新規混合ガスの流れの影響などに
よって取付金具８の端面３ａならびに第２接地電極鳴の
端面４ａに付着した導電性物質が間１１５に移動しにく
くなり、移動したとして４間ａＳ内で前述のブリッジを
形成するまでＫＦＪ至らない。In the present invention, the second ground electrode 4 is located inward from the end surface 8a of the mounting bracket 8 by setting the dimensions a and b in FIG. End face 4&
Since the distance from the end face 8a of the mounting bracket 8 to the gap becomes longer, the installation may be affected by the flow of combustion gas or new mixed gas flowing from the x direction in Figure 4. The conductive material attached to the end surface 3a of the metal fitting 8 and the end surface 4a of the second grounding electrode becomes difficult to move to the gap 115, and even if it does move, KFJ will not be reached until the above-mentioned bridge is formed within the 4 gap aS.

故に、間＠ｂ内での導電性物質のプリフジの形成による
半沿面火花ギャップ７に対する飛火が行なわれなくなる
という不具合を回避することができる。Therefore, it is possible to avoid the problem that sparks do not fly to the semi-creeping spark gap 7 due to the formation of a pre-fluge of the conductive material within the gap @b.

なお、第４図中のＹ方向の燃焼ガス、新規混合ガスの流
れに対しては、関１１５を通るそれらガスの流速が連く
なるため、とのＹ方向の流れの影響で間Ｂｉ１２内に上
記ブリッジが形成されることはない０ 本発明は前述の実施例に限定されず、以下のごとく種々
の変形が可能である。In addition, regarding the flow of combustion gas and new mixed gas in the Y direction in FIG. The above-mentioned bridge is not formed. The present invention is not limited to the above-described embodiments, and various modifications can be made as described below.

（１）第２１１地電極４ｔｆ環状で社なく、取付金具８
の内面の一ケ所に設けてあればよい。(1) No. 211 ground electrode 4tf ring-shaped, with mounting bracket 8
It is sufficient if it is provided in one place on the inner surface of the

（２）第２接地電極４は取付金具８に一体に設ける必要
Ｆｉなく、溶接により固定するようにしてもよい０ （８）第１接地電極８は中心電Ｍａｌの軸方向側面に対
向するようにしてもよい。(2) The second ground electrode 4 does not need to be integrally provided with the mounting bracket 8, and may be fixed by welding (8) The first ground electrode 8 is arranged so as to face the axial side surface of the central electric current You can also do this.

以上要するに、本発明によれば、半沿面火花ギャップと
気中火花ギャップとを備えた点火栓において、七〇半沿
面火花ギャップでの飛火をより確実なものとすることが
できるという効果がある。In summary, according to the present invention, in a spark plug equipped with a half creeping spark gap and an aerial spark gap, there is an effect that flying sparks in the 70 half creeping spark gap can be made more reliable.

４ｖ４、図面の簡単な説明 第１図は従来例を示す断面図、第２図は本発明の一実施
例を示す断面図、第８図は第２Ｆｌ！Ｊの底面図、第４
図は第２図の要部を拡大して示す断面図、第５ｖ！：ｉ
は本発明の詳細な説明に供する特性図である。4v4, Brief Description of the Drawings Fig. 1 is a sectional view showing a conventional example, Fig. 2 is a sectional view showing an embodiment of the present invention, and Fig. 8 is a 2nd Fl! Bottom view of J, 4th
The figure is a sectional view showing an enlarged view of the main part of Figure 2, No. 5v! :i
FIG. 2 is a characteristic diagram for explaining the present invention in detail.

ｌ・−・中心電極、２・・・絶縁碍子、２ａ・・・脚部
、８・・・取付金具、３畠・・・端面、８ｂ・・・内面
、４・・・第２接地電極、４ａ・・・端面、４ｂ・・・
間隙形成端、５・・・間隙、６・・・気中火花ギャップ
、７・・・半沿面火花ギャップ、８・・・第１接地電極
。l... Center electrode, 2... Insulator, 2a... Leg, 8... Mounting bracket, 3... End surface, 8b... Inner surface, 4... Second ground electrode, 4a... end face, 4b...
Gap forming end, 5... Gap, 6... Air spark gap, 7... Half creeping spark gap, 8... First ground electrode.

代理人弁理士　　岡　部　　隆Representative Patent Attorney Takashi Okabe

Claims (1)

【特許請求の範囲】 絶縁碍子と、この碍子の外周囲に固定した取付金具と、
前記碍子のうち内燃機関の燃焼室側に裸出する脚部の先
端より央出した中心電極と、前記金具に設けられ前記中
心電極との間に気中火花ギャップを形成した第１接地電
極と、前記碍子の前記脚部の外周に対し間隔を保持して
前記金具の内面に設けた第２の接地電極とを具備し、前
記脚部の絶縁抵抗低下時に社、前記気中火花ギャップに
飛火する要求電圧に対して前記中心電極と前記第２接地
電極との間で前記間隔および前記ｌｌｌＩＬ表面を経る
半沿面火花ギャップの飛火要求電圧が低くなるよう各部
寸法が調整されている内燃機関用点火栓であって、 前記金具の端面と前記第２接地電極の前記金具匈付根部
の端面との閣の寸法をａとし、かつ前記金具の内面と前
記第２接地電極の前記間隙形成端との間の寸法をｂとし
たとき、ａ、ｂとも少なくとも０．８鱈とした内燃機関
用点火栓。[Claims] An insulator, a mounting bracket fixed to the outer periphery of the insulator,
a center electrode extending from the tip of a leg portion of the insulator exposed toward the combustion chamber of the internal combustion engine; and a first ground electrode provided on the metal fitting and forming an air spark gap between the center electrode and the center electrode. and a second ground electrode provided on the inner surface of the metal fitting at a distance from the outer periphery of the leg of the insulator, so that when the insulation resistance of the leg decreases, sparks fly into the air spark gap. ignition for an internal combustion engine, wherein the dimensions of each part are adjusted so that the required voltage for sparking in the interval between the center electrode and the second ground electrode and the half creeping spark gap passing through the IllIL surface is lowered with respect to the required voltage; In the plug, the distance between the end face of the metal fitting and the end face of the root of the metal fitting of the second ground electrode is a, and the distance between the inner surface of the metal fitting and the gap forming end of the second ground electrode is a. A spark plug for an internal combustion engine in which both a and b are at least 0.8 mm, where b is the dimension between them.