JP3171198B2 - Glow plug for automotive internal combustion engine - Google Patents
Glow plug for automotive internal combustion engineInfo
- Publication number
- JP3171198B2 JP3171198B2 JP29407390A JP29407390A JP3171198B2 JP 3171198 B2 JP3171198 B2 JP 3171198B2 JP 29407390 A JP29407390 A JP 29407390A JP 29407390 A JP29407390 A JP 29407390A JP 3171198 B2 JP3171198 B2 JP 3171198B2
- Authority
- JP
- Japan
- Prior art keywords
- heating element
- glow plug
- tip
- axis
- internal combustion
- 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.)
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Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明はディーゼルエンジン等に適用されるグロープ
ラグに関し、特に、その発熱体の先端部形状の改良に関
する。Description: TECHNICAL FIELD The present invention relates to a glow plug applied to a diesel engine or the like, and more particularly, to an improvement in the shape of the tip of a heating element.
［従来の技術］ 実開昭60−32662号公報は、セラミック製のグロープ
ラグを開示する。[Background Art] Japanese Utility Model Publication No. Sho 60-32662 discloses a glow plug made of ceramic.
この公報に開示されるグロープラグの発熱体は、 第８図に示すようなグロープラグの構成を有し，、第
９図Ａに示すように、軸心に直角な断面が真円で、先端
部が発熱体の径の1/2乃至1/4の半径でかどを丸めた半球
状のものや、第９図Ｂに1bとして示すように先端部が部
分球状の発熱体が知られている。The heating element of the glow plug disclosed in this publication has the configuration of a glow plug as shown in FIG. 8, and as shown in FIG. 9A, the cross section perpendicular to the axis is a perfect circle, Known are a hemispherical part whose corner is rounded at a radius of 1/2 to 1/4 of the diameter of the heating element, and a partially spherical heating element as shown as 1b in FIG. 9B. .
上記公報には、従来技術として軸心に直角な断面が略
長方形で先端面が平坦な形状をもつセラミック発熱体も
開示されている。The above-mentioned publication also discloses, as a prior art, a ceramic heating element having a substantially rectangular cross section perpendicular to the axis and having a flat end surface.
一方、金属製の発熱体を有するグロープラグでは、発
熱体の先端部は、溶接などで製造される関係から略半球
状とすることが普通である。On the other hand, in the case of a glow plug having a metal heating element, the tip of the heating element is generally formed in a substantially hemispherical shape because it is manufactured by welding or the like.
［発明が解決しようとする課題］ 自動車用ディーゼル機関において、近年益々、排気ガ
ス浄化の要求が強まり、そのために多大な開発努力がな
されている。とりわけ、Noxの低減は重要課題であるが
その改善は容易ではない。[Problems to be Solved by the Invention] In automobile diesel engines, in recent years, demands for exhaust gas purification have been increasing, and a great deal of development effort has been made for that purpose. Above all, reducing Nox is an important issue, but its improvement is not easy.
上記公報のセラミック製発熱体は先端部が半球形状を
有し熱衝撃性に対しては優れているものの、第10図に示
す如くエンジンの副燃焼室に装着し、エミッション試験
を実施してするとNOx特性が悪いことがわかった。Although the ceramic heating element of the above publication has a hemispherical tip and is excellent in thermal shock resistance, it is mounted in a sub-combustion chamber of an engine as shown in FIG. 10 and an emission test is performed. NOx characteristics were found to be poor.
本発明は前記問題点に鑑みなされたものであり、エン
ジン性能を損うことなくNOxの低減が可能なグロープラ
グを提供することを、その目的としている。The present invention has been made in view of the above problems, and has as its object to provide a glow plug capable of reducing NOx without impairing engine performance.
［課題を解決するための手段］ 第１発明の内燃機関用グロープラグは、セラミックを
素材とする発熱体の先端部が副燃焼室内の燃料噴射ノズ
ルより噴射される燃料微粒子に直接接触する範囲内に設
けられ、前記発熱体の軸心が燃料噴射ノズルの噴射軸線
に対して斜交するグロープラグにおいて、前記発熱体の
先端部は、軸心に直角な断面が直径2.8mm以上の円形ま
たは楕円形で先端面が平坦な形状を有し、かつ、外周面
に接する前記先端面の周縁部が半径0.2〜1.0mm以下の丸
みを有することを特徴としている。[MEANS FOR SOLVING THE PROBLEMS] A glow plug for an internal combustion engine according to a first aspect of the present invention provides a glow plug in a range in which the tip of a heating element made of ceramic is in direct contact with fuel fine particles injected from a fuel injection nozzle in a sub-combustion chamber. In a glow plug in which the axis of the heating element is oblique to the injection axis of the fuel injection nozzle, the tip of the heating element has a circular or elliptical cross section perpendicular to the axis with a diameter of 2.8 mm or more. It is characterized in that the distal end surface has a flat shape and the peripheral portion of the distal end surface that contacts the outer peripheral surface has a radius of 0.2 to 1.0 mm or less.
第２発明の内燃機関用グロープラグは、金属を素材と
する発熱体の先端部が副燃焼室内の燃料噴射ノズルより
噴射される燃料微粒子に直接接触する範囲内に設けら
れ、前記発熱体の軸心が燃料噴射ノズルの噴射軸線対し
て斜交するグロープラグにおいて、前記発熱体の先端部
は、軸心に直角な断面が直径2.8mm以上の円形または楕
円形で先端面が平坦な形状を有し、かつ、外周面に接す
る前記先端面の周縁部が半径1.0mm以下の丸みを有する
ことを特徴としている。A glow plug for an internal combustion engine according to a second aspect of the present invention is provided such that a tip of a heating element made of a metal is provided in a range where the tip directly contacts fuel fine particles injected from a fuel injection nozzle in a sub-combustion chamber. In the glow plug, the center of which is oblique to the injection axis of the fuel injection nozzle, the tip of the heating element has a circular or elliptical cross section perpendicular to the axis with a diameter of 2.8 mm or more and a flat tip surface. In addition, a peripheral portion of the front end surface that is in contact with the outer peripheral surface has a radius of 1.0 mm or less.
発熱体は、SUS、ヘンズアロイ等の金属を用いること
ができ、又はSi3N4、MoSi2などのセラミックを用いるこ
ともできる。As the heating element, a metal such as SUS or Hens alloy can be used, or a ceramic such as Si 3 N 4 or MoSi 2 can be used.
なお本発明のグロープラグにおいて、発熱体の軸線と
燃料噴射ノズルの噴射軸線との交差角は鋭角とされて
おり、好ましくは、この交差角は20〜50度とされる。In the glow plug of the present invention, the intersection angle between the axis of the heating element and the injection axis of the fuel injection nozzle is an acute angle, and preferably, this intersection angle is 20 to 50 degrees.
発熱体の軸心と燃料噴射ノズルの噴射軸線との交点か
ら燃料噴射ノズルの噴射孔に至る直線の距離は15〜35mm
程度とするのが好ましい。The distance of the straight line from the intersection of the axis of the heating element and the injection axis of the fuel injection nozzle to the injection hole of the fuel injection nozzle is 15 to 35 mm
It is preferable to set the degree.
副燃焼室は略半球状又は略球状とされ、副燃焼室の容
積は10〜40程度、機関出力は30〜150馬力程度とするの
が好ましい。It is preferable that the sub-combustion chamber has a substantially hemispherical or substantially spherical shape, the volume of the sub-combustion chamber is about 10 to 40, and the engine output is about 30 to 150 horsepower.
上記楕円の長径は、2.8mm以上で、かつ、噴射軸線と
直交して配置されることが好ましい。このようにする
と、燃料及び空気の流れを阻害する効果が大きい。The major axis of the ellipse is preferably 2.8 mm or more, and is preferably arranged perpendicular to the injection axis. By doing so, the effect of obstructing the flow of fuel and air is large.
［作用］ 本発明者らは、種々実験の結果、単にグロープラグの
発熱体の先端部形状を工夫するだけで、NOxを低減でき
ることを発見した。正確な理由は不明であるが、上記の
形状及び配置条件を採用することによりセラミック製及
び金属製のグロープラグはNOx発生を低減する。[Operation] As a result of various experiments, the present inventors have found that NOx can be reduced simply by devising the shape of the tip of the heating element of the glow plug. Although the exact reason is unknown, the ceramic and metal glow plugs reduce NOx generation by employing the above shape and placement conditions.
すなわち、発熱体の先端部を平坦化して発熱体の軸線
を燃料噴射ノズルの噴射軸線に斜交させるとともに、発
熱体を燃料噴射ノズルが噴射する燃料微粒子に直接接触
する範囲内に設ければ、NOxを数％程度低減することが
できる。That is, if the tip of the heating element is flattened so that the axis of the heating element obliquely intersects with the injection axis of the fuel injection nozzle, and the heating element is provided in a range that directly contacts the fuel fine particles injected by the fuel injection nozzle, NOx can be reduced by about several percent.
この理由を推測するに、このような先端形状の発熱体
をノズルの噴射角度範囲内に配設すると、渦流の増加に
よる多少の燃焼促進効果は生じるものの、噴射された燃
料及び空気双方の流れや混合が邪魔されて燃焼が緩慢と
なり、そのため燃焼ガス温度が低下するなどしてNOxの
生成が減少するものと思われる。To guess the reason, if such a tip-shaped heating element is arranged within the injection angle range of the nozzle, although a slight combustion promotion effect is caused by the increase of the vortex, the flow of both the injected fuel and air and It is considered that the mixing is disturbed and the combustion is slowed down, so that the generation of NOx is reduced due to a decrease in the temperature of the combustion gas.
すなわち本発明によれば、グロープラグの発熱体によ
り渦の発生による燃焼促進効果以上に燃料及び空気の流
れを阻害する効果により、全体として燃焼の緩慢化によ
ると思われるNOx低減効果を実現したものである。That is, according to the present invention, the effect of inhibiting the flow of fuel and air by the heating element of the glow plug more than the effect of promoting combustion due to the generation of vortex, thereby achieving the NOx reduction effect which is considered to be due to the slowdown of combustion as a whole. It is.
［実施例］ 本発明の一実施例を正面図である第１図及び先端部平
面図である第２図に示す。[Embodiment] An embodiment of the present invention is shown in FIG. 1 which is a front view and FIG. 2 which is a plan view of a front end portion.
このグロープラグにおいて、１は発熱体、２は金属ホ
ルダーであり、発熱体１はセラミックからなり、発熱体
１の根元部は金属ホルダー２の内側に保持されている。
更に、発熱体１の金属ホルダー２とはロウ付けにより電
気的に接続されている。In this glow plug, 1 is a heating element, 2 is a metal holder, the heating element 1 is made of ceramic, and the root of the heating element 1 is held inside the metal holder 2.
Further, the heating element 1 is electrically connected to the metal holder 2 by brazing.
発熱体１は第２図に示すようにその軸心に直角な断面
が円形で断面の直径は3.5mmにされている。また、発熱
体１の先端面1bは平坦に形成されており、外周面1aに接
する先端面1bの周縁部1cは半径Ｒ＝0.2〜1.0mm以下の丸
みを有している。更に、金属ホルダ２から突出する発熱
体１の軸長Ｌは10mmに設定されている。As shown in FIG. 2, the heating element 1 has a circular cross section perpendicular to the axis thereof and a diameter of 3.5 mm. Further, the distal end face 1b of the heating element 1 is formed flat, and the peripheral edge 1c of the distal end face 1b in contact with the outer peripheral face 1a has a radius R of 0.2 to 1.0 mm or less. Further, the axial length L of the heating element 1 protruding from the metal holder 2 is set to 10 mm.
この発熱体１の取付け状態を第３図に、その拡大図を
第４図に示す。FIG. 3 shows the mounting state of the heating element 1, and FIG. 4 is an enlarged view of FIG.
第３図は車両ディーゼルエンジンの略球状の副燃焼室
を示す。副燃焼室12の下部にはシリンダ上部（図示せ
ず）に連通する連通孔11が設けられており、副燃焼室12
の上部には図中右方に燃料噴射ノズル13が設けられ、副
燃焼室12の上部の図中右方から発熱体１の発熱体１が垂
下している。FIG. 3 shows a substantially spherical auxiliary combustion chamber of a vehicle diesel engine. A communication hole 11 communicating with an upper part of the cylinder (not shown) is provided in a lower part of the sub-combustion chamber 12.
A fuel injection nozzle 13 is provided on the right side of the figure in the figure, and the heating element 1 of the heating element 1 hangs from the right side of the figure above the auxiliary combustion chamber 12.
ここで、燃料噴射ノズル13の噴射軸線Liと発熱体１の
軸線Lgとの交点Ｐから燃料噴射ノズル13の噴射孔Ｈに至
る直線Loと、発熱体１の軸線Lgとの交差角は31度に設
定されている。Here, the intersection angle between the straight line Lo from the intersection P of the injection axis Li of the fuel injection nozzle 13 and the axis Lg of the heating element 1 to the injection hole H of the fuel injection nozzle 13 and the axis Lg of the heating element 1 is 31 degrees. Is set to
また、直線Loの距離は20mm程度に設定され、副燃焼室
12の容積は約15ccとされ、機関出力は約75馬力に設定さ
れている。The distance of the straight line Lo is set to about 20 mm,
The capacity of the 12 is about 15cc, and the engine output is set to about 75 horsepower.
第４図中、L1、L2は燃料微粒子噴射流の上縁、下縁を
示し、したがって、上縁L1は発熱体１（実線で示す）と
Ｃ点に射突している。このＣ点から発熱体１先端面まで
の軸心に沿った長さLmはＡ点で4mm、Ｂ点で2mmに設定さ
れている。In FIG. 4, L1 and L2 indicate the upper edge and the lower edge of the fuel particulate injection flow, and therefore, the upper edge L1 collides with the heating element 1 (shown by a solid line) and point C. The length Lm along the axis from the point C to the end surface of the heating element 1 is set to 4 mm at the point A and 2 mm at the point B.
なおこの明細書では、燃料微粒子噴射流の上縁L1、下
縁L2で規定される噴霧角αの内部には、噴射される燃料
微粒子の90重量％が含まれるものとする。この実施例で
は、噴霧角αは70度に設定している。In this specification, it is assumed that the spray angle α defined by the upper edge L1 and the lower edge L2 of the fuel particle injection flow contains 90% by weight of the injected fuel particles. In this embodiment, the spray angle α is set to 70 degrees.
このセラミック発熱体１を製造するには、タングステ
ン線等よりなる発熱コイルをSi3N4よりなるセラミック
絶縁粉体中に埋設した後、プレスにより仮成形し、ホッ
トプレス焼結により一体焼結する。その後、研削により
軸方向の外形を真円に仕上げ、先端部端面1cも研削によ
り所望の形状に仕上げるて得られる。もちろん、発熱コ
イルをMoSi2等の導電性セラミックスよりなる発熱素子
としても良い。In order to manufacture the ceramic heating element 1, a heating coil made of a tungsten wire or the like is embedded in a ceramic insulating powder made of Si 3 N 4 , temporarily molded by a press, and integrally sintered by a hot press sintering. . Thereafter, the outer shape in the axial direction is finished to a perfect circle by grinding, and the end face 1c is also finished to a desired shape by grinding. Of course, the heating coil may be a heating element made of a conductive ceramic such as MoSi 2 .
副燃焼室12内部の空気流動が第３図に矢印で示され、
燃料噴射流の状態が第４図に矢印で示されている。吸入
行程でシリンダ内に吸入した空気は圧縮行程において連
通孔11から副燃焼室12内に押し込まれ、副燃焼室内でス
ワールとなる。一方噴射ノズル13より高圧で噴射された
燃料微粒子は高速噴霧流となり、その一部が発熱体１の
先端に射突する。The air flow inside the sub-combustion chamber 12 is indicated by an arrow in FIG.
The state of the fuel injection flow is indicated by an arrow in FIG. The air sucked into the cylinder in the suction stroke is pushed into the sub-combustion chamber 12 from the communication hole 11 in the compression stroke, and is swirled in the sub-combustion chamber. On the other hand, the fuel fine particles injected at a high pressure from the injection nozzle 13 become a high-speed spray flow, and a part thereof collides with the tip of the heating element 1.
従来形状（半球状）のセラミック発熱体及びこの実施
例の発熱体１を有するグロープラグについてNOxエミッ
ション特性を測定した。測定結果を第５図に示す。本試
験は排気量2000cc、副燃焼室を有するディーゼルエンジ
ンを搭載した乗用車においてJISに定める要領により10
モードエミッション試験を実施し、CO・HC・NOxを測定
するものである。第５図に示す様にＲを1.0mm以下にす
れば従来品（Ｒ＝1.75）に対してNOxは５％以上の大幅
な低減効果があり、平坦度が高いほど効果が大きいこと
がわかった。NOx emission characteristics were measured for a glow plug having a conventional shape (hemispherical) ceramic heating element and the heating element 1 of this embodiment. The measurement results are shown in FIG. This test was conducted on a passenger car equipped with a diesel engine with a displacement of 2000cc and a sub-combustion chamber in accordance with the JIS rules.
A mode emission test is performed to measure CO, HC, and NOx. As shown in FIG. 5, it was found that when R was set to 1.0 mm or less, the NOx had a significant reduction effect of 5% or more compared with the conventional product (R = 1.75), and the effect was larger as the flatness was higher. .
また、NOx低減効果は、発熱体１の先端位置によって
も変動し、先端面がＣ位置、Ｂ位置、Ａ位置と深くなる
につれ、効果は増大することがわかった。（第５図参
照）。Further, it was found that the NOx reduction effect also fluctuated depending on the tip position of the heating element 1, and the effect increased as the tip surface became deeper at the C position, the B position, and the A position. (See FIG. 5).
ただし、CO・HCについては、発熱体先端形状を変えて
も変化はほとんど見られなかった。However, for CO and HC, almost no change was observed even when the shape of the heating element tip was changed.
なお、この試験では発熱体１の直径Ｄは3.5mmとした
が、Ｄを大きくすればＲが一定でも発熱体１の軸心と平
行な断面形状がより角形化するので、更にNOx低減の効
果は改善される。一方、Ｄを縮小すると断面が従来品
（半球状）となるのでよくない。In this test, the diameter D of the heating element 1 was 3.5 mm. However, if D is increased, the cross-sectional shape parallel to the axis of the heating element 1 becomes more square even if R is constant. Is improved. On the other hand, if D is reduced, the cross section becomes a conventional product (hemispherical), which is not good.
また、発熱体１の断面を楕円に変更しても第５図と同
様な効果が得られた。Further, even when the cross section of the heating element 1 was changed to an ellipse, the same effect as in FIG. 5 was obtained.
第６図は耐熱衝撃性テストの結果を示したもので、試
料には発熱体先端研削面Ｒ寸法を各種変更したものを用
いた。テスト方法はグロープラグに所定温度になる様に
電圧を印加し、温度が十分安定した後に発熱体分を水中
に投入しクラック発生の有無を調査したものである。FIG. 6 shows the results of the thermal shock resistance test, in which the heat-generating body tip ground surface R dimension was variously changed. In the test method, a voltage was applied to the glow plug so as to reach a predetermined temperature, and after the temperature was sufficiently stabilized, the heating element was poured into water to check for cracks.
この試験から、Ｒを小さくしすぎるとセラミック製の
発熱体１の先端面1bの周縁部1cにクラックが生じやすく
なることがわかった。すなわち第６図からわかるよう
に、Ｒが0.2mm以下となると、急激にクラックが生じ、
グロープラグ温度が低下することがわかった。これは、
発熱体１の周縁部1cが急激急冷されやすく、その温度分
布が不均一となるためではないかと推測される。以上の
実施例では、セラミック製の発熱体１について述べた
が、金属製の発熱体１を有するシース型グロープラグに
ついても、同様の効果があることがわかった（第５図参
照）。ただし、金属製の発熱体１ではクラックは生じな
いので、上記Ｒは小さい方がよい。From this test, it was found that if R was made too small, cracks were likely to occur in the peripheral portion 1c of the tip surface 1b of the ceramic heating element 1. That is, as can be seen from FIG. 6, when R becomes 0.2 mm or less, cracks rapidly occur,
It was found that the glow plug temperature decreased. this is,
It is presumed that the peripheral portion 1c of the heating element 1 is easily cooled rapidly and the temperature distribution becomes non-uniform. In the above embodiment, the heating element 1 made of ceramic has been described. However, it has been found that the same effect can be obtained with a sheath-type glow plug having the heating element 1 made of metal (see FIG. 5). However, since a crack does not occur in the metal heating element 1, the above R is preferably smaller.
次に、第７図のモデルにおいて、発熱体１の軸線Lgと
燃料噴霧流の上縁L1との交点Ｋから軸線Lgと噴射軸線Li
との交点Ｐまでの距離Laと、発熱体１の平坦面1bから交
点Ｐまでの距離Lbを種々変更して更にNOxエミッション
特性を調べた。Next, in the model of FIG. 7, from the intersection K of the axis Lg of the heating element 1 and the upper edge L1 of the fuel spray flow, the axis Lg and the injection axis Li
NOx emission characteristics were further examined by variously changing the distance La from the flat surface 1b of the heating element 1 to the intersection P with the distance La to the intersection P.
その結果を第１表に示す。 Table 1 shows the results.
この結果からわかるように、Lb/Laが0.5以下であり、
かつ、発熱体１の曲率半径が1.0mm以下において、NOxを
５％以上低減できることが判明した。As can be seen from this result, Lb / La is 0.5 or less,
In addition, it has been found that NOx can be reduced by 5% or more when the radius of curvature of the heating element 1 is 1.0 mm or less.
また、第１表に示す試験において噴霧角αを４〜34度
の範囲で変更したが、結果は第１表と同様であった。 In the tests shown in Table 1, the spray angle α was changed in the range of 4 to 34 degrees, but the results were the same as in Table 1.
同様に、第１表に示す試験において交差角を20〜50
度の範囲で変更したが、この場合も結果は第１表と同様
であった。Similarly, in the test shown in Table 1, the crossing angle was 20 to 50.
The results were similar to those shown in Table 1 in the range of degrees.
［発明の効果］ 以上説明したように各発明のグロープラグは、発熱体
の先端部を軸心に直角な断面が円形又は楕円形で先端面
が平坦な形状に形成するとともに、セラミック製の発熱
体では先端面の周縁部に半径0.2〜1.0mm以下の丸みを与
え、金属製の発熱体では先端面の周縁部に半径1.0mm以
下の丸みを与えている。[Effects of the Invention] As described above, the glow plug according to each invention has a circular or elliptical cross section perpendicular to the front end of the heating element and a flat front end face, and also has a ceramic heating element. The body has a rounded edge with a radius of 0.2 to 1.0 mm or less at the periphery of the tip surface, and the metal heating element has a rounded edge with a radius of 1.0 mm or less at the periphery of the tip surface.
このようにすれば、クラック発生を防止しつつNOx発
生を顕著に低減できる。In this way, the generation of NOx can be significantly reduced while preventing the generation of cracks.
第１図は本発明の一実施例であってグロープラグ先端部
の正面図、第２図はその平面図、第３図は本実施例のグ
ロープラグの取付状態を示す断面図。第４図は第３図の
拡大図、第５図は本実施例のグロープラグの10モードエ
ミッションテストによるNOx低減効果を示す特性線図、
第６図は本実施例のグロープラグの耐熱衝撃性テスト結
果を示す図、第７図は本実施例のグロープラグの取付状
態を示す断面図、第８図は従来のグロープラグの全体正
面図、第９図は従来のグロープラグのセラミック製の発
熱体の一部拡大図、第10図は従来のグロープラグの取付
け状態を示す断面図である。 １……発熱体、1a……発熱体の外周面 1b……発熱体の先端面、1c……周縁部 ２……金属ホルダー 11……連通孔、12……副燃焼室 13……燃料噴射ノズルFIG. 1 is a front view of a tip portion of a glow plug according to an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a cross-sectional view showing a glow plug according to the embodiment. FIG. 4 is an enlarged view of FIG. 3, FIG. 5 is a characteristic diagram showing the NOx reduction effect of the glow plug of the present embodiment by the 10-mode emission test,
FIG. 6 is a view showing a thermal shock resistance test result of the glow plug of this embodiment, FIG. 7 is a sectional view showing an attached state of the glow plug of this embodiment, and FIG. 8 is an overall front view of a conventional glow plug. FIG. 9 is a partially enlarged view of a ceramic heating element of a conventional glow plug, and FIG. 10 is a cross-sectional view showing a mounted state of the conventional glow plug. Reference Signs List 1 heating element 1a outer peripheral surface of heating element 1b distal end surface of heating element 1c peripheral edge 2 metal holder 11 communication hole 12 auxiliary combustion chamber 13 fuel injection nozzle
───────────────────────────────────────────────────── フロントページの続き (72)発明者 正司 章 愛知県豊田市トヨタ町１番地 トヨタ自 動車株式会社内 (56)参考文献 特開 昭58−66720（ＪＰ，Ａ) 実開 昭57−190269（ＪＰ，Ｕ) 実開 昭61−23065（ＪＰ，Ｕ) 実開 昭60−326602（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) F23Q 7/00 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akira Shoji 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (56) References JP-A-58-66720 (JP, A) (JP, U) Japanese Utility Model Showa 61-23065 (JP, U) Japanese Utility Model Showa 60-326602 (JP, U) (58) Fields investigated (Int. Cl. 7 , DB name) F23Q 7/00
Claims (2)
副燃焼室内の燃料噴射ノズルより噴射される燃料微粒子
に直接接触する範囲内に設けられ、前記発熱体の軸心が
燃料噴射ノズルの噴射軸線に対して斜交する内燃機関用
グロープラグにおいて、前記発熱体の先端部は、軸心に
直角な断面が直径2.8mm以上の円形または楕円形で先端
面が平坦な形状を有し、かつ、外周面に接する前記先端
面の周縁部が半径0.2〜1.0mmの丸みを有することを特徴
とする内燃機関用グロープラグ。An end of a heating element made of ceramic is provided within a range in which the tip of the heating element is in direct contact with fuel fine particles injected from a fuel injection nozzle in a sub-combustion chamber. In the glow plug for an internal combustion engine oblique to the injection axis, the tip of the heating element has a flat cross-section perpendicular to the axis with a circular or elliptical tip having a diameter of 2.8 mm or more, A glow plug for an internal combustion engine, wherein a peripheral portion of the front end surface in contact with an outer peripheral surface has a radius of 0.2 to 1.0 mm.
室内の燃料噴射ノズルより噴射される燃料微粒子に直接
接触する範囲内に設けられ、前記発熱体の軸心が燃料噴
射ノズルの噴射軸線に対して斜交する内燃機関用グロー
プラグにおいて、前記発熱体の先端部は、軸心に直角な
断面が直径2.8mm以上の円形または楕円形で先端面が平
坦な形状を有し、かつ、外周面に接する前記先端面の周
縁部が半径1.0mm以下の丸みを有することを特徴とする
内燃機関用グロープラグ。2. A tip end of a heating element made of metal is provided in a range in which the tip end of the heating element directly contacts fuel fine particles injected from a fuel injection nozzle in a sub-combustion chamber. In the glow plug for an internal combustion engine oblique to the injection axis, the tip of the heating element has a flat cross-section perpendicular to the axis with a circular or elliptical tip having a diameter of 2.8 mm or more, A glow plug for an internal combustion engine, wherein a peripheral edge of the front end surface in contact with an outer peripheral surface has a radius of 1.0 mm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29407390A JP3171198B2 (en) | 1990-10-30 | 1990-10-30 | Glow plug for automotive internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29407390A JP3171198B2 (en) | 1990-10-30 | 1990-10-30 | Glow plug for automotive internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04165215A JPH04165215A (en) | 1992-06-11 |
| JP3171198B2 true JP3171198B2 (en) | 2001-05-28 |
Family
ID=17802935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29407390A Expired - Fee Related JP3171198B2 (en) | 1990-10-30 | 1990-10-30 | Glow plug for automotive internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3171198B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10082293B2 (en) | 2011-04-19 | 2018-09-25 | Ngk Spark Plug Co., Ltd. | Ceramic heater and manufacturing method thereof |
-
1990
- 1990-10-30 JP JP29407390A patent/JP3171198B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10082293B2 (en) | 2011-04-19 | 2018-09-25 | Ngk Spark Plug Co., Ltd. | Ceramic heater and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04165215A (en) | 1992-06-11 |
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