JPH0114673B2 - - Google Patents
Info
- Publication number
- JPH0114673B2 JPH0114673B2 JP54028002A JP2800279A JPH0114673B2 JP H0114673 B2 JPH0114673 B2 JP H0114673B2 JP 54028002 A JP54028002 A JP 54028002A JP 2800279 A JP2800279 A JP 2800279A JP H0114673 B2 JPH0114673 B2 JP H0114673B2
- Authority
- JP
- Japan
- Prior art keywords
- ground electrode
- electrode
- discharge
- opposing
- spark plug
- 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.)
- Expired
Links
- 238000002485 combustion reaction Methods 0.000 claims description 8
- 239000012212 insulator Substances 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 238000012856 packing Methods 0.000 claims description 2
- 238000001816 cooling Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Landscapes
- Spark Plugs (AREA)
Description
【発明の詳細な説明】
本発明は自動車等に用いられる点火プラグに関
し、その放電経路を制御し、着火性の向上を目的
としたものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark plug used in automobiles and the like, and is aimed at controlling the discharge path of the spark plug and improving ignition performance.
従来周知の点火プラグを第１図Ａ，Ｂ，Ｃに示
す。第１図において、従来周知の点火プラグは、
金製栓体１、前記栓体１に図示しないパツキンに
より固定されている絶縁体３、前記絶縁体により
囲まれ前記栓体１と絶縁されている中心電極２、
前記栓体１の端面に取り付けられ栓体１を通して
ボデイアースされる接地電極４により構成してあ
り、中心電極２と接地電極４は互に平行平面で対
向し、スパークギヤツプが形成されている。 Conventionally known spark plugs are shown in FIGS. 1A, B, and C. In FIG. 1, the conventionally known spark plug is
a metal stopper 1; an insulator 3 fixed to the stopper 1 by a packing (not shown); a center electrode 2 surrounded by the insulator and insulated from the stopper 1;
It consists of a ground electrode 4 attached to the end face of the plug 1 and grounded to the body through the plug 1. The center electrode 2 and the ground electrode 4 face each other in parallel planes, forming a spark gap.
前記従来周知の点火プラグにおいて、周知の電
流遮断方式の点火コイルにより発生した高電圧を
前記中心電極２に導き、放電を行なわせた時、放
電はエツジの部分で開始しやすいので、放電経路
は第２図のごとく中心電極２のエツジ部分（側
面）より接地電極４に第４図の斜線に示す部分に
向いやすい。かつ、斜線部の放電場所は毎回不規
則に移動する。従つて、放電経路によつて混合気
に着火し火炎の拡がり方に違いが生じる。 In the conventional well-known spark plug, when the high voltage generated by the well-known current interrupting type ignition coil is guided to the center electrode 2 to cause discharge, the discharge tends to start at the edges, so the discharge path is As shown in FIG. 2, the edge portion (side surface) of the center electrode 2 is more likely to be oriented toward the ground electrode 4 as shown by diagonal lines in FIG. In addition, the discharge location in the shaded area moves irregularly every time. Therefore, the way the air-fuel mixture ignites and the flame spreads varies depending on the discharge path.
第３図Ａ，Ｂ，Ｃ，Ｄは放電経路の違いにより
火炎の拡がり方を燃焼写真により観察した結果で
ある。図中、ｘ，ｙ，ｚは、点火してから一定時
間毎の火炎面を示している。第３図Ａは、放電経
路が接地電極４に対して奥即ち、第３図Ａの斜線
部ａの場合であり、火炎は接地電極４に沿つて拡
がつていき、接地電極４が火炎の拡がりを防害し
しかも火炎の熱を奪うので火炎の成長は遅い。こ
れに対して、第３図Ｂにおいては放電経路が接地
電極４の手前、即ち第３図Ａの斜線ｂであり、こ
の場合は放電の左方向は障害もないので、火炎は
拡がりやすく、第３図Ａに比べて燃焼の速度が非
常に速い。第３図Ｃ，Ｄは第３図Ａを左方向から
見た図であり、第３図Ｃの放電経路は第３図Ａと
同じ斜線部ａであり、第３図Ｄの放電経路は第３
図Ａの斜線部Ｃであつて接地電極４の端で放電し
ている。この第３図Ｄの方が火炎の拡がりが速い
ことがわかる。この実験例では、いずれの場合も
燃焼しているが、条件の悪い場合、例えば低温時
や、低速回転、点火時期が遅角している場合等で
混合気の霧化度が悪く流速が遅い場合には接地電
極４の妨害および冷却により、着火しても火炎が
途中で消滅してしまう。 FIGS. 3A, B, C, and D are the results of observing combustion photographs to see how the flame spreads due to differences in discharge paths. In the figure, x, y, and z indicate the flame front at fixed time intervals after ignition. FIG. 3A shows a case where the discharge path is deep to the ground electrode 4, that is, the shaded area a in FIG. 3A, and the flame spreads along the ground electrode 4, and the ground electrode 4 Since it prevents the spread of damage and also takes away the heat of the flame, the growth of the flame is slow. On the other hand, in FIG. 3B, the discharge path is in front of the ground electrode 4, that is, as indicated by the diagonal line b in FIG. The combustion speed is much faster than in Figure 3A. Figures 3C and 3D are views of Figure 3A viewed from the left; the discharge path in Figure 3C is the same shaded area a as in Figure 3A, and the discharge path in Figure 3D is the same as in Figure 3A. 3
Discharge occurs at the end of the ground electrode 4, which is the shaded area C in Figure A. It can be seen that the flame spreads faster in Figure 3D. In this experimental example, combustion occurs in all cases, but if the conditions are bad, such as at low temperatures, low speed rotation, or retarded ignition timing, the degree of atomization of the mixture is poor and the flow rate is slow. In some cases, even if the flame is ignited, it will be extinguished midway due to interference and cooling of the ground electrode 4.
このように、従来周知の点火プラグは放電の場
所により火炎の拡がり方が違うので、燃焼の変動
を生じさせる。さらに、エンジンの条件の悪い場
合は、ミスフアイアの原因ともなり、エンジンフ
イーリングの悪化、また排気対策のための触媒の
熱溶損を招くことになる。 In this way, in conventionally known spark plugs, the way the flame spreads differs depending on the location of discharge, resulting in fluctuations in combustion. Furthermore, if the engine conditions are unfavorable, it may cause misfire, resulting in deterioration of engine feeling and thermal melting of the catalyst for exhaust emissions.
一方、別の従来例として、第４図Ａ，Ｂに示す
ように接地電極４にその長手方向にＵ字形の溝４
ｅを設ける点火プラグが知られている。この点火
プラグは、接地電極４に溝４ｅがあるため、放電
により着火した火炎核が接地電極４と接する面積
は小さくなるので、冷却作用も小さくなり着火性
は改善されるが、放電場所は第５図の斜線部とな
り、その斜線部a1，a2で放電が行なわれた場合に
は、第３図Ａで説明したように接地電極４の長手
方向の冷却作用があるので、点火プラグ全体の着
火性能の向上はあまり十分とは言えない。 On the other hand, as another conventional example, as shown in FIGS. 4A and 4B, there is a U-shaped groove 4 in the longitudinal direction of the ground electrode 4.
Spark plugs are known that are provided with e. In this spark plug, since the ground electrode 4 has the groove 4e, the area in which the flame kernel ignited by the discharge comes into contact with the ground electrode 4 becomes small, so the cooling effect is also reduced and the ignition performance is improved, but the discharge location is If discharge occurs in the shaded areas a 1 and a 2 in Figure 5, there is a cooling effect in the longitudinal direction of the ground electrode 4 as explained in Figure 3A, so the entire spark plug is The improvement in ignition performance cannot be said to be very sufficient.
また、接地電極、中心電極が対向している部分
を針状にして電極による冷却をできる限り小さく
することが考えられる。しかし、この方法ではエ
ンジンの運転時間の経過に従つて電極が消耗して
放電ギヤツプが拡大し絶縁破壊電圧が上昇し、つ
いには放電しなくなつてしまう。 It is also conceivable to make the portion where the ground electrode and the center electrode face each other needle-shaped so that the cooling by the electrodes is made as small as possible. However, with this method, as the engine operating time progresses, the electrodes wear out, the discharge gap expands, the dielectric breakdown voltage increases, and eventually no discharge occurs.
本発明は、上述の種々の点に鑑みてなされたも
ので、従来プラグの接地電極の形状を変えること
で放電場所を規制し、全体としての着火性能の向
上と放電場所による火炎伝ぱの仕方の変動すなわ
ち燃焼の変動を小さくした点火プラグを得ること
を目的としたものである。 The present invention has been made in view of the various points mentioned above, and it regulates the discharge location by changing the shape of the ground electrode of the conventional plug, thereby improving the overall ignition performance and controlling the way flame spreads depending on the discharge location. The purpose of this invention is to obtain a spark plug with reduced fluctuations, that is, fluctuations in combustion.
以下本発明を実施例に従つて説明する。第６図
は本発明の一実施例を示す全体図である。この第
６図において、本発明の点火プラグは金属栓体
１、中心電極２、この中心電極２を前記栓体１か
ら絶縁する絶縁体３、前記栓体１に接続され、栓
体１を通してボデイアースされる接地電極４から
構成される。また、第７図Ａ，Ｂは第６図に示す
本発明点火プラグの火花放電部を拡大したもので
あり上記接地電極４には図に示すように、上記中
心電極２と上記接地電極４の対向距離の異なる２
つの対向面が形成されており、接地電極４の先端
側には放電が行われる平面をなす対向面である突
起部４ａが、また接地電極４の曲げ部４ｄには放
電が行われない対向面が形成されている。そし
て、この曲げ部側の対向面は上記中心電極２の径
l0よりも距離l1だけ先端面４ｂ寄りに位置してお
り、その突起部４ａは接地電極４の長手方向と直
角方向にその幅の全域に亘つて設けてある。 The present invention will be explained below based on examples. FIG. 6 is an overall view showing one embodiment of the present invention. In FIG. 6, the spark plug of the present invention includes a metal stopper 1, a center electrode 2, an insulator 3 that insulates the center electrode 2 from the stopper 1, and is connected to the stopper 1 and connected to the body ground through the stopper 1. It consists of a ground electrode 4. 7A and 7B are enlarged views of the spark discharge portion of the spark plug of the present invention shown in FIG. 2 with different facing distances
Two opposing surfaces are formed, and the tip side of the ground electrode 4 has a protruding portion 4a which is a flat opposing surface where discharge occurs, and the bent portion 4d of the ground electrode 4 has an opposing surface where no discharge occurs. is formed. The opposing surface on this bent side is the diameter of the center electrode 2.
It is located closer to the tip surface 4b by a distance l 1 than l 0 , and its protrusion 4 a is provided across the entire width of the ground electrode 4 in a direction perpendicular to the longitudinal direction of the ground electrode 4 .
なお、接地電極４の先端面４ｂは中心電極２の
側面２ｂの略垂線上にある。従つて、本実施例は
中心電極２の先端面２ｃと対向する接地電極４の
先端側の対向面である放電面４ｃは突起部４ａの
頂面であり、第１図Ｂの従来例より小さい。 Note that the tip surface 4b of the ground electrode 4 is substantially perpendicular to the side surface 2b of the center electrode 2. Therefore, in this embodiment, the discharging surface 4c, which is the opposing surface on the distal end side of the ground electrode 4 that faces the distal end surface 2c of the center electrode 2, is the top surface of the projection 4a, and is smaller than the conventional example shown in FIG. 1B. .
本実施例の放電場所は第７図Ｂに斜線で示して
ある。ここで、第７図Ａの距離l1（放電が行われ
ない接地電極の対向面の長さ）が小さすぎると、
中心電極２の側面２ａのエツジより第７図Ｂのd1
に放電が行なわれる場合が生じる。また、大き過
ぎると接地電極４の放電面４ｃが小さくなり電極
の消耗の点からは好ましくないので、両者の条件
を満たすように決定する必要がある。この際、l1
は中心電極２の径の1/3以上が望ましく、例えば
中心電極２の径が2.4mm程度で接地電極４の幅Ｗ
を2.4mmの場合には0.8〜1.4mmの範囲で選べばよ
い。また、突起部４ａの高さｈは放電、燃焼によ
る放電面の消耗に対しても中心電極２の側面２ａ
の垂線上に放電することのないように十分な高さ
が必要である。例えば0.5mm以上で選べばよい。
また中心電極２の径は上記の例で2.4mm程度とし
たが、１mmから3.2mmまで用途に合せて選べばよ
く、l1、突起の高さｈ、接地電極４の幅Ｗは中心
電極２の径に伴つて選べばよい。また接地電極４
の厚さt1は１mmから２mm程度選べばよい。なお、
接地電極４に突起部４ａを設ける方法は各種の切
削工作機械を用いることにより容易に実現でき
る。また、接地電極４の材質はニツケル合金等の
耐熱性、耐食性の良いものなら何でもよい。ま
た、接地電極４の突起部４ａおよびその他の端部
は多少の丸味をもたせてもよい。 The discharge locations in this embodiment are indicated by diagonal lines in FIG. 7B. Here, if the distance l 1 (the length of the opposing surface of the ground electrode where no discharge occurs) in FIG. 7A is too small,
d 1 in FIG. 7B from the edge of the side surface 2a of the center electrode 2
In some cases, a discharge occurs. Moreover, if it is too large, the discharge surface 4c of the ground electrode 4 will become small, which is undesirable from the viewpoint of electrode wear, so it is necessary to decide so as to satisfy both conditions. At this time, l 1
is preferably 1/3 or more of the diameter of the center electrode 2. For example, when the diameter of the center electrode 2 is about 2.4 mm, the width W of the ground electrode 4 is
In the case of 2.4mm, you can choose between 0.8 and 1.4mm. In addition, the height h of the protrusion 4a is set so that the side surface 2a of the center electrode 2 can withstand wear and tear on the discharge surface due to discharge and combustion.
Sufficient height is required to prevent discharge from perpendicular to the For example, you can choose 0.5mm or more.
The diameter of the center electrode 2 is about 2.4 mm in the above example, but it can be selected from 1 mm to 3.2 mm depending on the application. It should be selected according to the diameter. Also, the ground electrode 4
The thickness t 1 should be selected from about 1 mm to 2 mm. In addition,
The method of providing the protrusion 4a on the ground electrode 4 can be easily realized by using various cutting machine tools. Further, the material of the ground electrode 4 may be any material having good heat resistance and corrosion resistance, such as a nickel alloy. Further, the protruding portion 4a and other end portions of the ground electrode 4 may be slightly rounded.
次に、上記構成の本発明点火プラグの一実施例
の作用について説明する。中心電極２に高電圧を
印加すると絶縁破壊を起し、放電が行なわれる。
この時の放電の経路は電極２，４間の電界の分布
電極２，４の形状、電極２，４の表面の粗さ等に
より左右されるが、一般にエツジに放電しやすい
ので本発明の場合第７図Ｂの斜線部にて放電が行
なわれる。点火プラグ全体の着火性能を比べる場
合には、一番条件の悪い状態で比べる必要があ
る。そこで、第１図の従来プラグの場合は第２図
に示すａに放電が行なわれた時、第５図の従来プ
ラグの場合は第５図ａ１（あるいはａ２）に放電
した場合、本発明の第７図においてはｄ２（ある
いはｄ３）で放電した場合の火炎核が接地電極４
によつて冷却される程度を考察してみた。その結
果を第８図に示す。 Next, the operation of one embodiment of the spark plug of the present invention having the above structure will be explained. When a high voltage is applied to the center electrode 2, dielectric breakdown occurs and discharge occurs.
The path of the discharge at this time depends on the distribution of the electric field between the electrodes 2 and 4, the shape of the electrodes 2 and 4, the surface roughness of the electrodes 2 and 4, etc., but in general, discharge tends to occur at the edges, so in the case of the present invention Discharge occurs in the shaded area in FIG. 7B. When comparing the ignition performance of spark plugs as a whole, it is necessary to compare them under the worst conditions. Therefore, in the case of the conventional plug shown in FIG. 1, when discharge occurs at point a shown in FIG. 2, and in the case of the conventional plug shown in FIG. 5, when discharge occurs at point a1 (or a2) in FIG. In Fig. 7, the flame kernel when discharged at d2 (or d3) is at the ground electrode 4.
We considered the degree of cooling caused by The results are shown in FIG.
第８図Ａ１，Ａ２，Ａ３は第１図の従来プラ
グ、Ｂ１，Ｂ２，Ｂ３は第５図のＵ溝４ｋを設け
た従来プラグ、Ｃ１，Ｃ２，Ｃ３は第７図の本発
明プラグであり、それぞれ第７図におけるｘ方
向、ｙ方向、ｚ方向から見たモデル図である。な
お、第８図中の線イは放電経路、円形のロは火炎
核、斜線ハは火炎核ロが接地電極４に接して熱を
奪われる面を表わしている。この第８図から明ら
かなように、斜線部の面積は従来プラグ、Ｕ溝付
従来プラグ、本発明プラグの順に小さくなつてお
り、接地電極４による冷却作用は本発明プラグが
非常に小さいことが理解できる。 8A1, A2, and A3 are the conventional plugs shown in FIG. 1, B1, B2, and B3 are the conventional plugs provided with the U groove 4k shown in FIG. 5, and C1, C2, and C3 are the plugs of the present invention shown in FIG. , are model diagrams as seen from the x direction, y direction, and z direction in FIG. 7, respectively. Note that in FIG. 8, the line A represents the discharge path, the circular b represents the flame kernel, and the diagonal line C represents the surface where the flame kernel B comes into contact with the ground electrode 4 and from which heat is removed. As is clear from FIG. 8, the area of the shaded area decreases in the order of the conventional plug, the conventional U-groove plug, and the plug of the present invention, indicating that the cooling effect of the ground electrode 4 is extremely small for the plug of the present invention. It can be understood.
次に、第９図乃至第１２図に本発明の他の実施
例を示し、これを説明する。 Next, other embodiments of the present invention are shown in FIGS. 9 to 12, and will be described.
第９図Ａ，Ｂは第７図Ａに示すl1を大きくした
場合の実施例である。l1が大きい程、接地電極４
の冷却が小さく着火性の点からは良好と言える
が、あまりl1を大きくすると放電面の面積が小さ
くなり耐久的に好ましくないので、接地電極４の
先端面４ｂと中心電極２の側面２ｂとを図のよう
に距離ｎずらし、接地電極４の放電面４ｃを形成
する突起部４ａの長手方向の距離l2を確保したも
のである。なお、この実施例における放電場所を
第９図Ｂの斜線で示してある。図中、ｅ１，ｅ
２，ｅ３は第９図Ａのｎの長さが短かい時に放電
する場所である。この実施例においては、中心電
極２の径が2.4mm程度の場合には、例えばl1＝ｍ＝
1.2mmと固定すると、l2＝1.2＋ｎとなりl2＝２mm確
保したい時はｎ＝0.8mmとなる。 9A and 9B are examples in which l 1 shown in FIG. 7A is increased. The larger l 1 is, the more ground electrode 4
It can be said that it is good from the point of view of ignitability because the cooling is small, but if l 1 is increased too much, the area of the discharge surface will become small and it is not desirable in terms of durability. are shifted by a distance n as shown in the figure to ensure a distance l 2 in the longitudinal direction of the protrusion 4a forming the discharge surface 4c of the ground electrode 4. Note that the discharge locations in this embodiment are indicated by diagonal lines in FIG. 9B. In the figure, e1, e
2 and e3 are locations where discharge occurs when the length of n in FIG. 9A is short. In this embodiment, when the diameter of the center electrode 2 is about 2.4 mm, for example, l 1 =m=
If it is fixed at 1.2 mm, l 2 = 1.2 + n, and if you want to secure l 2 = 2 mm, n = 0.8 mm.
第１０図Ａ，Ｂは、接地電極４の先端側の対向
面である突起部を設けるかわりに、図に示すよう
に中心電極２の側面２ａの垂線より左右に渡る溝
４ｅを接地電極４の長手方向に対して直角に設け
たものである。ここで、溝４ｅのうち中心電極２
の側面２ａより右側の側面４ｅから側面２ａの垂
線に至る距離l3は溝４ｅの側面４ｆに放電しない
ように大きくとつてある。なお、l3は1.5mm以上が
望ましい。この実施例の放電場所が第１０図Ｂの
斜線部で示してある。 10A and 10B, instead of providing a protrusion on the opposing surface of the ground electrode 4 on the distal end side, a groove 4e extending left and right from the perpendicular line of the side surface 2a of the center electrode 2 is provided on the ground electrode 4 as shown in the figure. It is installed perpendicular to the longitudinal direction. Here, the center electrode 2 in the groove 4e
The distance l3 from the side surface 4e on the right side of the side surface 2a to the perpendicular line of the side surface 2a is set large so as not to cause discharge to the side surface 4f of the groove 4e. Note that l 3 is preferably 1.5 mm or more. The discharge location in this embodiment is shown by the shaded area in FIG. 10B.
第１１図は第１０図Ａに示す実施例の溝４ｅの
側面４ｇを放電面に対して角度θの傾きを持たせ
たものである。このθは溝４ｄの深さｈが浅い時
は大きく、深い時は小さくしても良く、通常は
30゜〜90゜程度の範囲で設定してやればよい。第１
１図Ｂに、この場合の放電場所を示す。 FIG. 11 shows the embodiment shown in FIG. 10A, in which the side surface 4g of the groove 4e is inclined at an angle θ with respect to the discharge surface. This θ may be large when the depth h of the groove 4d is shallow, and may be small when it is deep, and usually
The angle may be set within the range of 30° to 90°. 1st
Figure 1B shows the discharge location in this case.
第１２図は接地電極４の先端部を折り屈げて放
電面４ｃを形成した実施例であり、製作容易であ
る。 FIG. 12 shows an embodiment in which the distal end of the ground electrode 4 is bent to form a discharge surface 4c, which is easy to manufacture.
以上述べてきたように、本発明は接地電極４に
は、中心電極２の先端面と対向し、接地電極４と
の対向距離の異なる２つの対向面を段状に設け、
この２つの対向面のうち接地電極４の曲げ部４ｄ
側の対向面では放電が行われず、接地電極４の先
端部側の平面をなす対向面では、放電が行われる
ようにし、さらには接地電極の曲げ部４ｄ側の対
向面の長さl1が中心電極２の径の少なくとも1/3
以上としたので、火炎核の接地電極４による冷却
損失を小さくし、また接地電極４による火炎の伝
ぱの妨害をできるだけ小さく押えることができ、
その結果、着火性能の向上、燃焼の変動の低減を
実現できるという非常に大きな効果がある。ま
た、本発明は接地電極４の形状の改良だけで上記
効果を発揮できるから、点火電源あるいはエンジ
ン本体を改良し着火性能を向上させる場合に比べ
てコスト的に非常に有利である。 As described above, the present invention provides the ground electrode 4 with two facing surfaces facing the tip surface of the center electrode 2 and having different facing distances from the ground electrode 4 in a stepped manner.
The bent portion 4d of the ground electrode 4 among these two opposing surfaces
No discharge occurs on the facing surface on the side, but discharge occurs on the flat facing surface on the tip side of the ground electrode 4, and the length l 1 of the facing surface on the bent portion 4d side of the ground electrode is At least 1/3 of the diameter of center electrode 2
With the above, it is possible to reduce the cooling loss of the flame kernel due to the ground electrode 4, and to suppress the interference with the flame propagation due to the ground electrode 4 as much as possible.
As a result, there is a very large effect of improving ignition performance and reducing combustion fluctuations. Furthermore, since the present invention can achieve the above effects by simply improving the shape of the ground electrode 4, it is very advantageous in terms of cost compared to the case where the ignition performance is improved by improving the ignition power source or the engine body.
第１図Ａ，Ｂ，Ｃは従来の点火プラグを示すも
ので、第１図Ａは要部側面図、第１図Ｂは第１図
Ｂを拡大して示す正面図、第１図Ｃは第１図Ｂの
右側面図、第２図は第１図Ａ，Ｂ，Ｃの点火プラ
グの接地電極部の放電場所を示すモデル図、第３
図Ａ，Ｂ，Ｃ，Ｄは第１図の点火プラグの放電経
路の違いによる火炎核の成長過程を示したモデル
図、第４図Ａ，Ｂは従来の他の点火プラグの要部
を示す正面図および側面図、第５図は第４図に示
す従来の点火プラグの接地電極部の放電場所を示
すモデル図、第６図は本発明点火プラグの一実施
例を示す全体図、第７図Ａは第６図図示の要部を
示す要部拡大図、第７図Ｂは第７図Ａの放電場所
を示すモデル図、第８図において、Ａ１，Ａ２，
Ａ３は第１図図示の従来点火プラグ、Ｂ１，Ｂ
２，Ｂ３は第２図図示の他の従来点火プラグＣ
１，Ｃ２，Ｃ３は第６図図示の本発明点火プラグ
のそれぞれ第７図Ａに示すｘ，ｙ，ｚ方向からみ
た放電経路、火炎核の状態を示すモデル図、第９
図Ａ，Ｂ乃至第１２図Ａ，Ｂは本発明点火プラグ
の他の実施例を示す要部拡大図、および放電場所
を示すモデル図である。
１…栓体、２…中心電極、２ａ…その側面、３
…絶縁体、４…接地電極、４ａ…突起部、４ｂ…
先端面、４ｃ…放電面、４ｄ…曲げ部、４ｅ…
溝。
Figures 1A, B, and C show conventional spark plugs. Figure 1A is a side view of the main parts, Figure 1B is an enlarged front view of Figure 1B, and Figure 1C is an enlarged front view of Figure 1B. Figure 1B is a right side view, Figure 2 is a model diagram showing the discharge location of the ground electrode of the spark plug in Figures 1A, B, and C;
Figures A, B, C, and D are model diagrams showing the flame kernel growth process due to the different discharge paths of the spark plug in Figure 1, and Figures 4 A and B show the main parts of other conventional spark plugs. 5 is a model diagram showing the discharge location of the ground electrode portion of the conventional spark plug shown in FIG. 4; FIG. 6 is an overall view showing one embodiment of the spark plug of the present invention; FIG. Figure A is an enlarged view of the main parts shown in Figure 6, Figure 7B is a model diagram showing the discharge location in Figure 7A, and Figure 8 shows A1, A2,
A3 is the conventional spark plug shown in Figure 1, B1, B
2, B3 is another conventional spark plug C shown in Figure 2.
1, C2, and C3 are model diagrams showing the state of the discharge path and flame kernel as seen from the x, y, and z directions shown in FIG. 7A, respectively, of the ignition plug of the present invention shown in FIG. 6;
FIGS. A, B to FIG. 12 A, B are enlarged views of main parts showing other embodiments of the ignition plug of the present invention, and model diagrams showing discharge locations. DESCRIPTION OF SYMBOLS 1... Plug body, 2... Center electrode, 2a... Its side surface, 3
...Insulator, 4...Ground electrode, 4a...Protrusion, 4b...
Tip surface, 4c...Discharge surface, 4d...Bending portion, 4e...
groove.
Claims (1)
介して固定された絶縁体と、この絶縁体のうちエ
ンジンの燃焼室内に裸出する脚部に保持された中
心電極と、前記栓体の端部に設けられ前記中心電
極の先端面に端部が対向するよう屈曲された接地
電極とを備え、この接地電極と前記中心電極との
間で放電を行うよう構成した点火プラグにおい
て、 前記接地電極には、前記中心電極の先端面と対
向し、前記中心電極との対向距離の異なる２つの
対向面がほぼ段状に設けられ、この２つの対向面
のうち前記接地電極の曲げ部側の対向面の対向距
離を、放電が行われない距離とし、前記接地電極
の先端部側の平面をなす対向面の対向距離を放電
が行われる距離とし、 前記接地電極の前記曲げ部側の対向面の長さl1
が前記中心電極の径の少なくとも1/3以上であり、
前記接地電極の先端側の対向面のみで放電を行う
ようにしたことを特徴とする点火プラグ。 ２ 前記接地電極の先端側の対向面を突起部とす
ることにより放電が行われる対向距離とすること
を特徴とする特許請求の範囲第１項記載の点火プ
ラグ。 ３ 前記接地電極の曲げ部側の対向面を、前記接
地電極の長手方向に対して直角に設けた溝とする
ことにより放電が行われない対向距離とすること
を特徴とする特許請求の範囲第１項記載の点火プ
ラグ。 ４ 前記接地電極の先端部を折り曲げ形成するこ
とにより、前記曲げ部側の対向面および前記先端
側の対向面を形成することを特徴とする特許請求
の範囲第１項記載の点火プラグ。[Scope of Claims] 1. A metal stopper, an insulator fixed to the inside of the stopper via a packing, and a center portion of the insulator held by a leg exposed inside the combustion chamber of the engine. an electrode, and a ground electrode provided at an end of the plug body and bent so that its end faces the distal end surface of the center electrode, and configured to generate an electric discharge between the ground electrode and the center electrode. In the spark plug, the ground electrode is provided with two opposing surfaces facing the tip surface of the center electrode and having different opposing distances from the center electrode, and of the two opposing surfaces, the The facing distance of the facing surfaces on the bent side of the ground electrode is the distance at which no discharge occurs, and the facing distance between the facing surfaces forming a plane on the tip side of the ground electrode is the distance at which the discharge occurs. Length of the opposing surface on the bent side side l 1
is at least 1/3 or more of the diameter of the center electrode,
1. A spark plug characterized in that discharge occurs only on the opposing surface on the tip side of the ground electrode. 2. The spark plug according to claim 1, wherein the opposing surface on the distal end side of the ground electrode is formed into a protruding portion to provide an opposing distance at which discharge occurs. 3. The opposing surface of the ground electrode on the bent side side is formed into a groove provided at right angles to the longitudinal direction of the ground electrode, thereby providing an opposing distance at which no discharge occurs. The spark plug described in item 1. 4. The spark plug according to claim 1, wherein the tip of the ground electrode is bent to form a surface facing the bent portion and a surface facing the tip.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2800279A JPS55121290A (en) | 1979-03-09 | 1979-03-09 | Ignition plug |
| US06/123,819 US4331899A (en) | 1979-03-09 | 1980-02-22 | Spark plug |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2800279A JPS55121290A (en) | 1979-03-09 | 1979-03-09 | Ignition plug |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55121290A JPS55121290A (en) | 1980-09-18 |
| JPH0114673B2 true JPH0114673B2 (en) | 1989-03-13 |
Family
ID=12236582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2800279A Granted JPS55121290A (en) | 1979-03-09 | 1979-03-09 | Ignition plug |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55121290A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4730747B2 (en) * | 2007-03-29 | 2011-07-20 | 日本特殊陶業株式会社 | Spark plug and manufacturing method thereof |
| JP4716296B2 (en) | 2007-03-29 | 2011-07-06 | 日本特殊陶業株式会社 | Spark plug manufacturing method and spark plug |
| JP4692588B2 (en) * | 2007-07-31 | 2011-06-01 | 株式会社デンソー | Spark plug for internal combustion engine and method for manufacturing the same |
| US8466608B2 (en) | 2008-10-14 | 2013-06-18 | Ngk Spark Plug Co., Ltd. | Spark plug and manufacturing method thereof |
| CN102177630B (en) * | 2008-10-16 | 2014-04-23 | 日本特殊陶业株式会社 | Spark plug and manufacturing method thereof |
| WO2010044249A1 (en) * | 2008-10-16 | 2010-04-22 | 日本特殊陶業株式会社 | Spark plug and method for the manufacture thereof |
| JP4567800B1 (en) * | 2009-07-10 | 2010-10-20 | 日本特殊陶業株式会社 | Spark plug for internal combustion engine and method for manufacturing the same |
| JP5423485B2 (en) * | 2010-03-05 | 2014-02-19 | 株式会社デンソー | Spark plug for internal combustion engine |
| JP6390636B2 (en) * | 2016-02-16 | 2018-09-19 | 株式会社豊田中央研究所 | Internal combustion engine |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2069320A (en) * | 1935-07-17 | 1937-02-02 | Dean D Francis | Spark plug |
| JPS5341299A (en) * | 1976-09-27 | 1978-04-14 | Mitsubishi Electric Corp | Issuing apparatus of pass |
-
1979
- 1979-03-09 JP JP2800279A patent/JPS55121290A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2069320A (en) * | 1935-07-17 | 1937-02-02 | Dean D Francis | Spark plug |
| JPS5341299A (en) * | 1976-09-27 | 1978-04-14 | Mitsubishi Electric Corp | Issuing apparatus of pass |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55121290A (en) | 1980-09-18 |
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