JP2021105353A - Internal combustion engine with auxiliary combustion chamber - Google Patents

Internal combustion engine with auxiliary combustion chamber Download PDF

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JP2021105353A
JP2021105353A JP2019236427A JP2019236427A JP2021105353A JP 2021105353 A JP2021105353 A JP 2021105353A JP 2019236427 A JP2019236427 A JP 2019236427A JP 2019236427 A JP2019236427 A JP 2019236427A JP 2021105353 A JP2021105353 A JP 2021105353A
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combustion chamber
injection hole
sub
flame injection
flame
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JP7405604B2 (en
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悟 嶋崎
Satoru Shimazaki
悟 嶋崎
幸希 森永
Yukimare Morinaga
幸希 森永
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Daihatsu Motor Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

To significantly suppress heat loss by reducing the amount of flame directed toward a piston from a sub-flame injection hole while improving scavenging property/air-fuel mixture inflow property by forming the downward sub-frame injection hole on an auxiliary combustion chamber.SOLUTION: An auxiliary combustion chamber 13 is provided with a main flame injection hole 14 opened in a direction crossing a cylinder bore shaft center O, and an auxiliary flame injection hole 15 opened in the direction of the cylinder bore shaft center O. An earth electrode 19 of an ignition plug 17 is provided with a partitioning portion 19b for vertically dividing the inside of the auxiliary combustion chamber 13 at a lower part of the main flame injection hole 14. An upper space 20 and a lower space 21 are communicated to each other. Most of a combustion gas generated by discharging of the ignition plug 17 is jetted from the main flame injection hole 14 to a main combustion chamber, and only weak flame is jetted from the auxiliary flame injection hole 15.SELECTED DRAWING: Figure 1

Description

本願発明は、副燃焼室付き内燃機関に関するものである。 The present invention relates to an internal combustion engine with an auxiliary combustion chamber.

内燃機関において、シリンダヘッドに副燃焼室（副室）を設けることが提案されている。副燃焼室は点火プラグの代わりに設けられており、副燃焼室で発生した火炎を主燃焼室に噴出させて主燃料に着火させる。副燃焼室で生成した火炎は燃料の着火性に優れているため、混合気の燃料がリーン気味であっても確実に燃焼させることができる利点がある。そこで、排気ガスクリーン化促進の有望な技術として注目されている。 In an internal combustion engine, it has been proposed to provide a sub-combustion chamber (sub-chamber) in the cylinder head. The sub-combustion chamber is provided in place of the spark plug, and the flame generated in the sub-combustion chamber is ejected into the main combustion chamber to ignite the main fuel. Since the flame generated in the sub-combustion chamber is excellent in ignitability of the fuel, there is an advantage that the fuel of the air-fuel mixture can be reliably burned even if it is lean. Therefore, it is attracting attention as a promising technology for promoting exhaust gas screen.

副燃焼室には火炎噴孔（トーチ孔）が形成されており、通常は、火炎噴孔は、例えば特許文献１の図１〜３に開示されているように、シリンダボア軸心に対して傾斜した方向に開口しているが、特許文献１の図４に開示されているように、シリンダボア軸心に対して傾斜した方向に開口した火炎噴孔に加えて、シリンダボア軸心方向に開口した火炎噴孔を設けることも提案されている。 A flame injection hole (torch hole) is formed in the sub-combustion chamber, and the flame injection hole is usually inclined with respect to the cylinder bore axis as disclosed in FIGS. 1 to 3 of Patent Document 1, for example. However, as disclosed in FIG. 4 of Patent Document 1, in addition to the flame injection hole opened in the direction inclined with respect to the cylinder bore axis, the flame opened in the cylinder bore axis direction. It has also been proposed to provide a fountain.

特開２００１−２２７３４４号公報Japanese Unexamined Patent Publication No. 2001-227344

副燃焼室内の燃焼ガスは排気行程において火炎噴孔から排出され（掃気され）、吸気行程において混合気が副燃焼室内に火炎噴孔から入り込むが、副燃焼室の火炎噴孔がシリンダボア軸心に対して傾斜したものだけであると、副燃焼室内で燃焼ガスに淀みが発生しやすくて掃気性が悪いという問題がある。 The combustion gas in the sub-combustion chamber is discharged (scavenged) from the flame injection hole in the exhaust stroke, and the air-fuel mixture enters the sub-combustion chamber through the flame injection hole in the intake stroke. On the other hand, if only the one is inclined, there is a problem that stagnation is likely to occur in the combustion gas in the sub-combustion chamber and the scavenging property is poor.

他方、特許文献１の図４のようにシリンダボア軸心方向に開口した火炎噴孔を設けると、副燃焼室内で燃焼ガスの流れが発生することにより、燃焼ガスの掃気性を向上できると共に、吸気行程でも流れの発生によって混合気の流入性を向上できる利点がある。 On the other hand, if a flame injection hole opened in the axial direction of the cylinder bore is provided as shown in FIG. 4 of Patent Document 1, the flow of combustion gas is generated in the sub-combustion chamber, so that the scavenging property of the combustion gas can be improved and the intake air is taken. There is an advantage that the inflow of the air-fuel mixture can be improved by generating a flow even in the process.

このように、副燃焼室にシリンダボア軸心方向に開口した火炎噴孔を設けることは、燃焼ガスの掃気性向上と混合気の流入性向上との利点を有するが、シリンダボア軸心方向に開口した火炎噴孔から噴出した燃焼ガスはピストンの頂面に向かうため、ピストンに奪われる熱量が大きくて熱損失が大きいという問題がある。また、ピストンの特定部位が火炎に集中的に晒されることによるピストンの局部昇温により、ノッキングが発生しやすくなることも懸念される。 In this way, providing a flame injection hole that opens in the direction of the axis of the cylinder bore in the auxiliary combustion chamber has the advantages of improving the scavenging property of the combustion gas and improving the inflow of the air-fuel mixture, but it opens in the direction of the axis of the cylinder bore. Since the combustion gas ejected from the flame injection hole goes to the top surface of the piston, there is a problem that the amount of heat taken by the piston is large and the heat loss is large. In addition, there is a concern that knocking is likely to occur due to the local temperature rise of the piston due to the concentrated exposure of a specific portion of the piston to the flame.

本願発明は、このような現状を改善すべく成されたものである。 The present invention has been made to improve such a situation.

本願発明の内燃機関は、
「主燃焼室の略中央部に露出するようにシリンダヘッドに設けられた副燃焼室と、シリンダボア軸心と略同心状に配置されて中心電極と接地電極とを前記副燃焼室内に露出させた状態で前記シリンダヘッドに取り付けられた点火プラグとを備えており、
前記副燃焼室に、シリンダボア軸心に対して交叉した方向に開口したメイン火炎噴孔と、シリンダボア軸心方向に開口したサブ火炎噴孔とが形成されている」
という基本構成において、
「前記点火プラグの接地電極に、副燃焼室の内部を前記メイン火炎噴孔に連通した上部空間と前記サブ火炎噴孔に連通した下部空間とに分ける仕切り部が設けられており、前記上部空間と下部空間とを互いに連通させている」
という特徴を有している。 The internal combustion engine of the present invention is
"The sub-combustion chamber provided in the cylinder head so as to be exposed in the substantially central portion of the main combustion chamber and the center electrode and the ground electrode arranged substantially concentrically with the cylinder bore axis were exposed in the sub-combustion chamber. It is equipped with a spark plug attached to the cylinder head in the state.
In the sub-combustion chamber, a main flame injection hole opened in the direction intersecting the cylinder bore axis and a sub flame injection hole opened in the direction of the cylinder bore axis are formed. "
In the basic configuration
"The ground electrode of the spark plug is provided with a partition portion that divides the inside of the sub-combustion chamber into an upper space communicating with the main flame injection hole and a lower space communicating with the sub flame injection hole. And the lower space communicate with each other. "
It has the feature.

本願発明において、副燃焼室に充満した混合気に点火プラグで発生した火花によって点火されるが、点火プラグの中心電極と接地電極とは上部空間に配置されているため、混合気は主として上部空間において燃焼して、高圧の燃焼ガスがメイン火炎噴孔から噴出する。 In the present invention, the air-fuel mixture filled in the sub-combustion chamber is ignited by sparks generated by the spark plug, but since the center electrode and the ground electrode of the spark plug are arranged in the upper space, the air-fuel mixture is mainly in the upper space. Combustion in, high-pressure combustion gas is ejected from the main flame outlet.

他方、サブ火炎噴孔に溜まっていた混合気にも上部空間の火炎が伝播して燃焼するが、上下の空間は仕切り部によって分けられていて上部空間の火炎が下部空間に向かうことが抑制されるため、下部空間での燃焼量と燃焼圧は上部空間でのそれに比べて低くなっている。従って、ピストンに向かう火炎は大幅に弱くなる。従って、ピストンに奪われる熱量を抑制して熱損失を低減できると共に、ピストンの局部的昇温を防止してノッキング防止に貢献できる。 On the other hand, the flame in the upper space propagates to the air-fuel mixture accumulated in the sub-flame injection hole and burns, but the upper and lower spaces are separated by a partition, and the flame in the upper space is suppressed from going toward the lower space. Therefore, the amount of combustion and the combustion pressure in the lower space are lower than those in the upper space. Therefore, the flame towards the piston is significantly weakened. Therefore, the amount of heat taken by the piston can be suppressed to reduce heat loss, and the local temperature rise of the piston can be prevented to contribute to the prevention of knocking.

また、副燃焼室の上部空間と下部空間とは互いに連通しているため、排気行程においては燃焼ガス流れを形成できて掃気性に優れている一方、吸気行程では混合気の流れを形成できて混合気流入性に優れている。 Further, since the upper space and the lower space of the sub-combustion chamber communicate with each other, a combustion gas flow can be formed in the exhaust stroke and excellent scavenging property, while an air-fuel mixture flow can be formed in the intake stroke. Excellent air-fuel mixture inflow.

従って、本願発明では、副燃焼室内での燃焼ガスと混合気との入れ換え性を向上させて安定した燃焼を実現させつつ、ピストンに放熱されることによる熱損失を大幅に抑制して燃費の向上とノッキング防止とに貢献できる。 Therefore, in the present invention, the interchangeability of the combustion gas and the air-fuel mixture in the sub-combustion chamber is improved to realize stable combustion, and the heat loss due to heat dissipated to the piston is significantly suppressed to improve fuel efficiency. And can contribute to knocking prevention.

第１実施形態を示す図で、（Ａ）はクランク軸線方向から見た縦断面図、（Ｂ）は（Ａ）のＢ−Ｂ視平断面図、（Ｃ）は（Ａ）のＣ−Ｃ視断面図である。In the figure which shows the 1st Embodiment, (A) is a vertical sectional view seen from the direction of the crank axis, (B) is a sectional view taken along line BB of (A), and (C) is CC of (A). It is a cross-sectional view. （Ａ）は燃焼行程での縦断面図、（Ｂ）は吸気行程での縦断面図である。(A) is a vertical cross-sectional view in the combustion stroke, and (B) is a vertical cross-sectional view in the intake stroke. （Ａ）は第２実施形態の平断面図で（Ｂ）のＡ−Ａ視断面図、（Ｂ）は（Ａ）のＢ−Ｂ視断面図、（Ｃ）は第３実施形態の平断面図、（Ｄ）は第４実施形態の縦断面図、（Ｅ）は（Ｄ）のＥ−Ｅ視断面図、（Ｆ）は第５実施形態の縦断面図、（Ｇ）は（Ｆ）のＧ−Ｇ視断面図、（Ｈ）は第６実施形態の縦断面図、（Ｉ）は（Ｈ）のＩ−Ｉ視断面図である。(A) is a plan sectional view of the second embodiment, (B) is a sectional view taken along the line AA, (B) is a sectional view taken along the line BB of (A), and (C) is a plan sectional view of the third embodiment. FIG., (D) is a vertical cross-sectional view of the fourth embodiment, (E) is a sectional view taken along the line EE of (D), (F) is a vertical cross-sectional view of the fifth embodiment, and (G) is (F). GG is a cross-sectional view taken along the line GG, (H) is a vertical cross-sectional view of the sixth embodiment, and (I) is a cross-sectional view taken along the line II of (H).

(1).第１実施形態
次に、本願発明の実施形態を図面に基づいて説明する。まず、図１，２に示す第１実施形態を説明する。本実施形態は自動車用内燃機関に適用しており、内燃機関は、基本的要素としてシリンダブロック１とその上面にガスケット２を介して固定されたシリンダヘッド３とを有しており、シリンダブロック１には、クランク軸線方向に並んだ複数のシリンダボア４が形成されている。 (1). First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. First, the first embodiment shown in FIGS. 1 and 2 will be described. This embodiment is applied to an internal combustion engine for automobiles, and the internal combustion engine has a cylinder block 1 and a cylinder head 3 fixed to the upper surface thereof via a gasket 2 as basic elements, and the cylinder block 1 Is formed with a plurality of cylinder bores 4 arranged in the direction of the crank axis.

他方、シリンダヘッド３には、シリンダボア４に向いた円錐状の凹所５が形成されており、シリンダブロック１のシリンダボア４とシリンダヘッド３の凹所５とによって主燃焼室６が形成されている。当然ながら、シリンダボア４にはピストン７が摺動自在に嵌まっている。なお、ピストン７の頂面には凹部７ａが形成されている。 On the other hand, the cylinder head 3 is formed with a conical recess 5 facing the cylinder bore 4, and the main combustion chamber 6 is formed by the cylinder bore 4 of the cylinder block 1 and the recess 5 of the cylinder head 3. .. As a matter of course, the piston 7 is slidably fitted in the cylinder bore 4. A recess 7a is formed on the top surface of the piston 7.

シリンダヘッド３には、各凹所５に対応して、一対ずつの吸気ポート８と一対ずつの排気ポート９とが、クランク軸線を挟んだ両側に形成されている。吸気ポート８は吸気バルブ１０で開閉され、排気ポート９は排気バルブ１１で開閉される。各吸気ポート８は、それぞれシリンダヘッド３の吸気側面に開口している。 In the cylinder head 3, a pair of intake ports 8 and a pair of exhaust ports 9 are formed on both sides of the crank axis so as to correspond to each recess 5. The intake port 8 is opened and closed by the intake valve 10, and the exhaust port 9 is opened and closed by the exhaust valve 11. Each intake port 8 is open to the intake side surface of the cylinder head 3.

他方、各対の排気ポート９は、シリンダヘッド３に形成された集合通路に集まっており、集合通路には１つの排気出口穴が形成されて、排気出口穴はシリンダヘッド３の排気側面に開口している。 On the other hand, each pair of exhaust ports 9 are gathered in a collecting passage formed in the cylinder head 3, one exhaust outlet hole is formed in the collecting passage, and the exhaust outlet hole is opened on the exhaust side surface of the cylinder head 3. is doing.

そして、シリンダヘッド３のうち凹所５の略中央部に、主燃焼室６に露出した副燃焼室１３を配置している。副燃焼室１３は筒状で底部（下端）は半球状に湾曲しており、筒状の部分に、シリンダボア軸心Ｏに対して交叉した方向に開口した複数（例えば３〜８個）のメイン火炎噴孔１４が形成されて、下端（底部）には、シリンダボア軸心Ｏと同心状のサブ火炎噴孔１５が形成されている。 A sub-combustion chamber 13 exposed to the main combustion chamber 6 is arranged in a substantially central portion of the recess 5 of the cylinder head 3. The sub-combustion chamber 13 is tubular and the bottom (lower end) is curved in a hemispherical shape, and a plurality of mains (for example, 3 to 8) are opened in the tubular portion in a direction intersecting the cylinder bore axis O. A flame injection hole 14 is formed, and a sub-flame injection hole 15 concentric with the cylinder bore axis O is formed at the lower end (bottom portion).

また、副燃焼室１３は、シリンダヘッド３に上からねじ込み又は圧入された筒状で段付きの本体部１６を備えており、本体部１６に点火プラグ１７がねじ込みによって固定されている。 Further, the sub-combustion chamber 13 includes a tubular and stepped main body portion 16 screwed or press-fitted into the cylinder head 3 from above, and a spark plug 17 is fixed to the main body portion 16 by screwing.

点火プラグ１７はシリンダボア軸心Ｏと略同心に配置されており、点火プラグ１７の下端には、副燃焼室１３の内部に露出した中心電極１８と接地電極１９とを設けている。中心電極１８は、台座１８ａに中心極芯１８ｂを設けた構成である一方、接地電極１９は、プラグ本体から延出したアーム部１９ａと、アーム部１９ａの下端に一体に設けた仕切り部（仕切り板）１９ｂと、仕切り部１９ｂから上向きに突設した接地極芯１９ｃとを備えており、仕切り部１９ｂはメイン火炎噴孔１４の下方に位置している。 The spark plug 17 is arranged substantially concentrically with the cylinder bore axis O, and a center electrode 18 and a ground electrode 19 exposed inside the sub-combustion chamber 13 are provided at the lower end of the spark plug 17. The center electrode 18 has a configuration in which a central electrode core 18b is provided on the pedestal 18a, while the ground electrode 19 has an arm portion 19a extending from the plug body and a partition portion (partition) integrally provided at the lower end of the arm portion 19a. A plate) 19b and a grounding electrode core 19c projecting upward from the partition portion 19b are provided, and the partition portion 19b is located below the main flame injection hole 14.

従って、副燃焼室１３の内部は、仕切り部１９ｂにより、メイン火炎噴孔１４と連通した上部空間２０と、サブ火炎噴孔１５に連通した下部空間２１とに区分されており、両空間２０，２１は、仕切り部１９ｂの外側の環状通路によって連通している。上部空間２０の容積は、下部空間２１の容積よりも大きくなっている。本実施形態では、仕切り部１９ｂは、アーム部１９ａと連接した側が幅狭となるように平面視で窄んだ形状になっている（おたまじゃくし状になっている。）。 Therefore, the inside of the sub-combustion chamber 13 is divided into an upper space 20 communicating with the main flame injection hole 14 and a lower space 21 communicating with the sub-flame injection hole 15 by the partition portion 19b. 21 is communicated by an annular passage on the outside of the partition portion 19b. The volume of the upper space 20 is larger than the volume of the lower space 21. In the present embodiment, the partition portion 19b has a shape narrowed in a plan view so that the side connected to the arm portion 19a becomes narrow (it has a tadpole shape).

(2).まとめ
図２（Ａ）はピストン７が上死点付近にあって点火プラグ１７に通電した状態を示しているが、中心電極１８と接地電極１９との間のギャップに発生した火花は上部空間２０に充満している混合気に着火し、上部空間２０の火炎が下部空間２１に伝播して、下部空間２１での燃焼が行われる。 (2). Summary Fig. 2 (A) shows a state in which the piston 7 is near top dead center and the spark plug 17 is energized, but sparks generated in the gap between the center electrode 18 and the ground electrode 19 Ignites the air-fuel mixture that fills the upper space 20, the flame of the upper space 20 propagates to the lower space 21, and combustion is performed in the lower space 21.

そして、下部空間２１での燃焼はいわば二次的なものであり、主たる燃焼は上部空間２０において行われるため、高圧で太い火炎がメイン火炎噴孔１４から噴出して遠くまで飛んでいく。これにより、主燃焼室６に充満していた混合気に一気に着火させることができる。他方、下部空間２１で発生した燃焼によって火炎がサブ火炎噴孔１５から下方に向かうが、下部空間２１での燃焼量は少なくて圧力も低いため、ピストン７に対する伝熱量は僅かであり、大きな熱損失が生じることもない。また、ピストン７の頂面が局部的に過剰昇温することもなくて、ノッキングを防止できる。 The combustion in the lower space 21 is so to speak secondary, and the main combustion is performed in the upper space 20, so that a thick flame at high pressure is ejected from the main flame injection hole 14 and flies far away. As a result, the air-fuel mixture filled in the main combustion chamber 6 can be ignited at once. On the other hand, the combustion generated in the lower space 21 causes the flame to move downward from the sub-flame injection hole 15, but since the amount of combustion in the lower space 21 is small and the pressure is low, the amount of heat transferred to the piston 7 is small and large heat is generated. There is no loss. Further, knocking can be prevented because the top surface of the piston 7 does not locally overheat.

他方、排気行程では、排気ガスは、吸気側のメイン火炎噴孔１４から排気側のメイン火炎噴孔１４に流れたり、サブ火炎噴孔１５から排気側のメイン火炎噴孔１４に流れたりして副燃焼室１３の内部に排気ガスの流れができるため、燃焼ガスは副燃焼室１３に残留することなく掃気される。 On the other hand, in the exhaust stroke, the exhaust gas flows from the main flame injection hole 14 on the intake side to the main flame injection hole 14 on the exhaust side, or flows from the sub flame injection hole 15 to the main flame injection hole 14 on the exhaust side. Since the exhaust gas flows inside the sub-combustion chamber 13, the combustion gas is swept without remaining in the sub-combustion chamber 13.

そして、図２（Ｂ）に示すように、吸気行程では、吸気ポート８から噴出した混合気が吸気側のメイン火炎噴孔１４から排気側のメイン火炎噴孔１４及びサブ火炎噴孔１５に向かって流れるため、副燃焼室１３の内部に混合気の流れが形成されて、副燃焼室１３の内部を新たな混合気で充満させることができる。従って、燃料がリーン気味の混合気であっても安定した燃焼を実現できる。 Then, as shown in FIG. 2B, in the intake stroke, the air-fuel mixture ejected from the intake port 8 goes from the main flame injection hole 14 on the intake side to the main flame injection hole 14 and the sub flame injection hole 15 on the exhaust side. Therefore, a flow of the air-fuel mixture is formed inside the sub-combustion chamber 13, and the inside of the sub-combustion chamber 13 can be filled with a new air-fuel mixture. Therefore, stable combustion can be realized even if the fuel is a lean mixture.

(3).他の実施形態
図３では他の実施形態を示している。このうち図３（Ａ）（Ｂ）に示す第２実施形態では、仕切り部１９ｂを点火プラグ１７とは別体で平面視円形に形成してアーム部１９ａの下面に溶接等で固定している。このように仕切り部１９ｂを円形に形成すると、上下空間２０，２１の仕切り機能が向上するため、サブ火炎噴孔１５から噴出する火炎の量を更に抑制できる。仕切り部１９ｂは点火プラグ１７と別体であるため、大きさや厚さを任意に設定できて融通性に優れている。既存の点火プラグ１７に容易に適用できる利点もある。 (3). Other Embodiments Fig. 3 shows other embodiments. Of these, in the second embodiment shown in FIGS. 3A and 3B, the partition portion 19b is formed in a circular shape in a plan view separately from the spark plug 17, and is fixed to the lower surface of the arm portion 19a by welding or the like. .. When the partition portion 19b is formed in a circular shape in this way, the partition function of the upper and lower spaces 20 and 21 is improved, so that the amount of flame ejected from the sub-flame injection hole 15 can be further suppressed. Since the partition portion 19b is separate from the spark plug 17, the size and thickness can be arbitrarily set, and the partition portion 19b is excellent in flexibility. It also has the advantage of being easily applicable to existing spark plugs 17.

図３（Ｃ）に示す第３実施形態では、アーム部１９ａの下端に円板状の仕切り部１９ｂを一体に設けている。 In the third embodiment shown in FIG. 3C, a disk-shaped partition portion 19b is integrally provided at the lower end of the arm portion 19a.

図３（Ｄ）（Ｅ）に示す第４実施形態では、副燃焼室１３の内部に円板状の仕切り部１９ｂを溶接などで固定し、仕切り部１９ｂに筒状の接地極芯１９ｃを形成している。従って、第４実施形態では、副燃焼室１３が接地電極１７の一部を構成している。また、接地極芯１９ｃで囲われた部分が、上部空間２０と下部空間２１とを連通させる連通路２２になっている。 In the fourth embodiment shown in FIGS. 3D and 3E, a disk-shaped partition 19b is fixed inside the auxiliary combustion chamber 13 by welding or the like, and a tubular grounding electrode core 19c is formed in the partition 19b. is doing. Therefore, in the fourth embodiment, the sub-combustion chamber 13 constitutes a part of the ground electrode 17. Further, the portion surrounded by the grounding electrode core 19c is a communication passage 22 that communicates the upper space 20 and the lower space 21.

この第４実施形態では、上部空間２０と下部空間２１との連通路の断面積は僅かであるため、上部空間２０から下部空間２１への火炎の伝播量は従前の実施形態よりも少なくなっている。従って、下部空間２１で発生する燃焼ガスの圧力は低くなっており、結果として、火炎がピストン７に当たることによる熱損失を殆ど無くすことができる。 In this fourth embodiment, since the cross-sectional area of the communication passage between the upper space 20 and the lower space 21 is small, the amount of flame propagation from the upper space 20 to the lower space 21 is smaller than that in the conventional embodiment. There is. Therefore, the pressure of the combustion gas generated in the lower space 21 is low, and as a result, the heat loss due to the flame hitting the piston 7 can be almost eliminated.

図３の（Ｆ）（Ｇ）に示す第５実施形態は第４実施形態の変形例であり、仕切り部１９ｂの中心部に接地極芯１９ｃを設けて、接地極芯１９ｃの外側に複数の連通路２２を形成している。この実施形態では、接地極芯１９ｃは棒状であるため、放電を安定化できる利点がある。また、連通路２２の数や大きさ、配置を選択することより、上部空間２０から下部空間２１への火炎伝播を最適化できる。図の上部空間２０では、連通路２２を隣り合ったメイン火炎噴孔１４の間に配置することにより、下部空間２１への火炎の逃げを抑制している。 The fifth embodiment shown in FIGS. 3 (F) and (G) is a modification of the fourth embodiment, in which a grounding electrode core 19c is provided at the center of the partition portion 19b, and a plurality of grounding electrode cores 19c are provided outside the grounding electrode core 19c. It forms a communication passage 22. In this embodiment, since the grounding electrode core 19c has a rod shape, there is an advantage that the discharge can be stabilized. Further, by selecting the number, size, and arrangement of the communication passages 22, the flame propagation from the upper space 20 to the lower space 21 can be optimized. In the upper space 20 of the figure, the passage 22 is arranged between the adjacent main flame injection holes 14 to suppress the escape of the flame to the lower space 21.

図３のうち（Ｈ）（Ｉ）に示す第６実施形態では、第３，４実施形態と同様に仕切り部１９ｂは円板状に形成されているが、仕切り部１９ｂは複数本のアーム部１９ａを介して点火プラグ１７に一体化されている。そして、副燃焼室１３の内部に、仕切り部１９ｂが重なる段部２３を形成している。また、第５実施形態と同様に、仕切り部１９ｂに複数の連通路２２を形成している。 In the sixth embodiment shown in FIGS. 3H and 3I, the partition portion 19b is formed in a disk shape as in the third and fourth embodiments, but the partition portion 19b has a plurality of arm portions. It is integrated with the spark plug 17 via 19a. Then, inside the sub-combustion chamber 13, a step portion 23 on which the partition portions 19b overlap is formed. Further, as in the fifth embodiment, a plurality of communication passages 22 are formed in the partition portion 19b.

本実施形態では、電流はアーム部１９ａからアースできるため、副燃焼室１３と仕切り部１９ｂとを電気的に絶縁できる。従って、電流の拡散はなくて火花形成の安定性に優れている。また、本実施形態のように接地電極１９を１３とは別体に形成してアーム部１９ａから電流をアースさせると、接地電極１９は電気特性に優れた素材を使用できることによる火花形成機能の向上効果もある。更に、複数のアーム部１９ａを形成すると、ギャップ寸法の変化を防止できると共に電気抵抗を低減させてアース機能を向上できるため、火花の形成を更に安定化できて好適である。 In the present embodiment, since the current can be grounded from the arm portion 19a, the sub-combustion chamber 13 and the partition portion 19b can be electrically insulated. Therefore, there is no current diffusion and the stability of spark formation is excellent. Further, when the ground electrode 19 is formed separately from the 13 and the current is grounded from the arm portion 19a as in the present embodiment, the ground electrode 19 can improve the spark forming function by using a material having excellent electrical characteristics. There is also an effect. Further, when the plurality of arm portions 19a are formed, it is possible to prevent a change in the gap size and reduce the electric resistance to improve the grounding function, which is preferable because the formation of sparks can be further stabilized.

以上、本願発明の実施形態を説明したが、本願発明は他にも様々に具体化できる。例えば、仕切り部１９ｂは平面視で角形などにも形成できる。副燃焼室は、シリンダヘッドに下方からねじ込んで固定したり、凹部の下面に溶接で固定したりすることも可能である。 Although the embodiments of the present invention have been described above, the present invention can be embodied in various ways. For example, the partition portion 19b can be formed into a square shape or the like in a plan view. The sub-combustion chamber can be screwed into the cylinder head from below and fixed, or can be fixed to the lower surface of the recess by welding.

本願発明は、実際に内燃機関に具体化できる。従って、産業上利用できる。 The invention of the present application can be actually embodied in an internal combustion engine. Therefore, it can be used industrially.

３ シリンダヘッド
４ シリンダボア
７ ピストン
１４ メイン火炎噴孔
１５ サブ火炎噴孔
１７ 点火プラグ
１８ 中心電極
１９ 接地電極
１９ａ アーム部
１９ｂ 仕切り部
１９ｃ 接地極芯
２０ 上部空間
２１ 下部空間
Ｏ シリンダボア軸心 3 Cylinder head 4 Cylinder bore 7 Piston 14 Main flame injection hole 15 Sub flame injection hole 17 Spark plug 18 Center electrode 19 Ground electrode 19a Arm part 19b Partition part 19c Grounding electrode core 20 Upper space 21 Lower space O Cylinder bore axis

Claims (1)

主燃焼室の略中央部に露出するようにシリンダヘッドに設けられた副燃焼室と、シリンダボア軸心と略同心状に配置されて中心電極と接地電極とを前記副燃焼室内に露出させた状態で前記シリンダヘッドに取り付けられた点火プラグとを備えており、
前記副燃焼室に、シリンダボア軸心に対して交叉した方向に開口したメイン火炎噴孔と、シリンダボア軸心方向に開口したサブ火炎噴孔とが形成されている構成であって、
前記点火プラグの接地電極に、副燃焼室の内部を前記メイン火炎噴孔に連通した上部空間と前記サブ火炎噴孔に連通した下部空間とに分ける仕切り部が設けられており、前記上部空間と下部空間とを互いに連通させている、
副燃焼室付き内燃機関。 A state in which the sub-combustion chamber provided in the cylinder head so as to be exposed in the substantially central portion of the main combustion chamber and the center electrode and the ground electrode are arranged substantially concentrically with the cylinder bore axis so as to be exposed in the sub-combustion chamber. It is equipped with a spark plug attached to the cylinder head.
In the sub-combustion chamber, a main flame injection hole opened in the direction intersecting the cylinder bore axis and a sub flame injection hole opened in the cylinder bore axis direction are formed.
The ground electrode of the spark plug is provided with a partition portion that divides the inside of the sub-combustion chamber into an upper space communicating with the main flame injection hole and a lower space communicating with the sub flame injection hole. Communicating with the lower space,
Internal combustion engine with auxiliary combustion chamber.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5669416A (en) * 1979-11-11 1981-06-10 Yariichi Hisada Unit consisting of accessory chamber and spark plug
JPH04287826A (en) * 1991-03-19 1992-10-13 Nissan Motor Co Ltd Spark ignition internal combustion engine of auxiliary chamber
JPH11224763A (en) * 1997-10-24 1999-08-17 Jun Sato Spark plug provided with sub combustion chamber for fuel ignition system
JP2011214492A (en) * 2010-03-31 2011-10-27 Denso Corp Ignition plug and engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5669416A (en) * 1979-11-11 1981-06-10 Yariichi Hisada Unit consisting of accessory chamber and spark plug
JPH04287826A (en) * 1991-03-19 1992-10-13 Nissan Motor Co Ltd Spark ignition internal combustion engine of auxiliary chamber
JPH11224763A (en) * 1997-10-24 1999-08-17 Jun Sato Spark plug provided with sub combustion chamber for fuel ignition system
JP2011214492A (en) * 2010-03-31 2011-10-27 Denso Corp Ignition plug and engine

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