JP5561957B2 - Sub-combustion chamber ignition device - Google Patents

Sub-combustion chamber ignition device Download PDF

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JP5561957B2
JP5561957B2 JP2009114180A JP2009114180A JP5561957B2 JP 5561957 B2 JP5561957 B2 JP 5561957B2 JP 2009114180 A JP2009114180 A JP 2009114180A JP 2009114180 A JP2009114180 A JP 2009114180A JP 5561957 B2 JP5561957 B2 JP 5561957B2
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combustion chamber
sub
ignition
laser
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JP2010261407A (en
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彰浩 安藤
高伸 青地
正道 柴田
光一 服部
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Denso Corp
Soken Inc
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Denso Corp
Nippon Soken Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P13/00—Sparking plugs structurally combined with other parts of internal-combustion engines
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Ignition Installations For Internal Combustion Engines (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Description

本発明は、内燃機関の点火に用いられる副燃焼室式点火装置の着火性の向上及び液体燃料の付着による失火の防止に関する。   The present invention relates to improvement in ignitability of an auxiliary combustion chamber type ignition device used for ignition of an internal combustion engine and prevention of misfire due to adhesion of liquid fuel.

近年、自動車エンジン等の内燃機関において、燃焼排気中に含まれる、窒素酸化物や二酸化炭素、未燃炭化水素化合物等の排出量低減やさらなる燃費の向上を図るべく、内燃機関の極希薄化、高過給化について種々と提案されており、また、極希薄内燃機関や高過給内燃機関等の難着火性機関においても良好な点火が実現可能な点火装置について種々と提案されている。   In recent years, in an internal combustion engine such as an automobile engine, in order to reduce emissions of nitrogen oxides, carbon dioxide, unburned hydrocarbon compounds, etc. contained in combustion exhaust gas and to further improve fuel consumption, Various proposals have been made for high supercharging, and various ignition devices capable of realizing good ignition even in inflammable engines such as extremely lean internal combustion engines and high supercharged internal combustion engines have been proposed.

特許文献１には、主燃焼室と、前記燃焼室に隣接し、連通孔を介して前記燃焼室に連通されている副燃焼室と、前記副燃焼室に設けられた点火部と、前記主燃焼室に導入される新気混合気を旋回させて、前記主燃焼室に前記新気混合気の旋回流を形成させる旋回流形成部と、少なくとも気体燃料を前記主燃焼室へ噴射する気体燃料噴射部と、前記新気混合気の旋回流を介して前記主燃焼室から前記副燃焼室へ前記気体燃料が導入されるように、前記気体燃料噴射部を制御する第１制御部と、を備えた副燃焼室式内燃機関が開示されている。   Patent Document 1 discloses a main combustion chamber, a sub-combustion chamber adjacent to the combustion chamber and communicating with the combustion chamber via a communication hole, an ignition unit provided in the sub-combustion chamber, and the main combustion chamber. A swirl flow forming section that swirls a fresh air mixture introduced into the combustion chamber to form a swirl flow of the fresh air mixture in the main combustion chamber, and a gaseous fuel that injects at least gaseous fuel into the main combustion chamber An injection unit, and a first control unit that controls the gaseous fuel injection unit so that the gaseous fuel is introduced from the main combustion chamber to the auxiliary combustion chamber via a swirling flow of the fresh air mixture. An auxiliary combustion chamber internal combustion engine is disclosed.

特許文献１にあるような、従来の副燃焼室式内燃機関では、液体燃料に比べて層流燃焼速度の大きい気体燃料を副燃焼室内に導入して、点火プラグの火花放電によって、副燃焼室内の気体燃料に点火し、短い燃焼期間でトーチ状の火炎を発生させ、主燃焼室内に噴射することによってリーン限界の拡大を図っている。   In the conventional subcombustion chamber internal combustion engine as disclosed in Patent Document 1, gaseous fuel having a laminar combustion speed larger than that of liquid fuel is introduced into the subcombustion chamber, and spark discharge of the spark plug causes a spark combustion in the subcombustion chamber. The gas fuel is ignited, a torch-like flame is generated in a short combustion period, and injected into the main combustion chamber to expand the lean limit.

特許文献２には、レーザ発信装置からのレーザ光を、シリンダヘッドに装着されて該レーザ光を集光するレーザ光集光装置に伝送し、該レーザ光集光装置から集光レーザ光を燃焼室内に照射して発生させたプラズマにより前記燃焼室内のガスに着火するように構成されたレーザ着火式エンジンにおいて、前記レーザ発信装置に、前記燃焼室内におけるレーザ正常着火を可能とするパルス時間間隔にて複数パルスのレーザ光を発信せしめるレーザ光発信制御手段を備えたことを特徴とする複数パルスレーザ照射レーザ着火式エンジンが開示されている。   In Patent Document 2, laser light from a laser transmitting device is transmitted to a laser light condensing device that is attached to a cylinder head and condenses the laser light, and the condensed laser light is burned from the laser light condensing device. In a laser ignition type engine configured to ignite gas in the combustion chamber by plasma generated by irradiation inside the chamber, the laser transmission device has a pulse time interval that enables normal laser ignition in the combustion chamber. There is disclosed a multi-pulse laser irradiation laser ignition type engine equipped with laser light transmission control means for transmitting a plurality of pulses of laser light.

特許文献３には、開口部と該開口部に対向した底面とをもち軸方向に伸びる断面が円形のチャンバーを区画するハウジングと、該ハウジングの表面に設けられ該チャンバーの開口部と外部とを連通する外部電極孔をもつ外部電極と、該チャンバーの該底面に配置された中心電極と、を有し、該中心電極と該外部電極との間に電圧を印加して該チャンバー内にプラズマを発生させ、該チャンバーの開口部からプラズマジェットを噴射する内燃機関用点火装置であって、該チャンバーの容積が１０ｍｍ３以下であり、かつ該チャンバーの軸方向の長さと内径の長さとの比が２以上であることを特徴とする内燃機関用点火装置が開示されている。 In Patent Document 3, a housing that has an opening and a bottom surface facing the opening, and that defines a chamber having a circular cross section extending in the axial direction, and the opening provided on the surface of the housing and the outside of the chamber are provided. An external electrode having an external electrode hole communicating therewith, and a central electrode disposed on the bottom surface of the chamber, and a voltage is applied between the central electrode and the external electrode to generate plasma in the chamber. An ignition device for an internal combustion engine for generating and injecting a plasma jet from an opening of the chamber, wherein the chamber has a volume of 10 mm 3 or less, and a ratio of an axial length and an inner diameter length of the chamber is There is disclosed an internal combustion engine ignition device characterized by two or more.

ところが、本発明者等の鋭意試験により、特許文献１にあるような従来の副燃焼室式内燃機関においては、副燃焼室内における起爆位置が主燃焼室と副燃焼室とを連通する連通孔から副燃焼室の容積重心以上に離れている場合には、副燃焼室内で発生した高温ガスの低温部が先に主燃焼室内に噴射され、着火タイミングに遅れが生じる虞があることが判明した。
さらに、液体燃料を主燃焼室内に直接噴射する直噴式内燃機関において、このような副燃焼室式内燃機関を実現しようとした場合、液体燃料が上記連通孔に液滴状となって付着したり、長期の使用によって未燃炭化水素化合物等からなるデポジットが蓄積したりして、トーチ状火炎の噴出経路が塞がれ、着火性の低下を招く虞もある。 However, in the conventional auxiliary combustion chamber type internal combustion engine as disclosed in Patent Document 1, it has been determined that the initiation position in the auxiliary combustion chamber is from a communication hole that connects the main combustion chamber and the auxiliary combustion chamber. It has been found that when the center of gravity of the auxiliary combustion chamber is more than the center of gravity, the low temperature portion of the high temperature gas generated in the auxiliary combustion chamber is first injected into the main combustion chamber, and the ignition timing may be delayed.
Further, in a direct injection internal combustion engine that directly injects liquid fuel into the main combustion chamber, when trying to realize such a sub-combustion chamber internal combustion engine, the liquid fuel adheres in droplets to the communication holes. In addition, deposits made of unburned hydrocarbon compounds and the like may accumulate due to long-term use, and the ejection path of the torch-like flame may be blocked, resulting in a decrease in ignitability.

また、特許文献２にあるように燃焼室内に強力なレーザ光を集光させて点火を行う場合、さらなる希薄化を実現すべく燃焼室内に強い気流を形成すると、レーザ光の集光により発生した火炎核が十分な大きさに成長しないうちに、強い筒内気流に晒されるため、火炎核が吹き消されるように燃焼速度の低下を招き、不安定な着火となる虞がある。
さらに、従来のレーザ点火装置を燃焼室内に直接高圧燃料が噴射される直噴式内燃機関の点火に用いた場合、特に低温始動時においては、噴射された燃料が液滴状に凝縮して、レーザ光の集光経路に付着するため、焦点に乱れを生じ、着火に必要なエネルギ密度まで安定して集光することができなくなり不安定な着火となる虞もある。 Further, as disclosed in Patent Document 2, when ignition is performed by concentrating powerful laser light in the combustion chamber, a strong air flow is formed in the combustion chamber to realize further dilution, which is generated by condensing the laser light. Before the flame kernel grows to a sufficient size, the flame kernel is exposed to a strong in-cylinder airflow, so that the combustion speed is lowered so that the flame kernel is blown out, and unstable ignition may occur.
Furthermore, when the conventional laser ignition device is used for ignition of a direct injection internal combustion engine in which high pressure fuel is directly injected into the combustion chamber, the injected fuel is condensed into droplets, particularly at low temperature start, and the laser Since it adheres to the light condensing path, the focal point is disturbed, and the energy density required for ignition cannot be stably collected, which may cause unstable ignition.

特許文献３にあるようなプラズマ点火装置では、チャンバー内に高電圧の印加と大電流の供給とを行うことにより、チャンバー内の気体が電離して高温高圧のプラズマ状態となって噴射され、優れた着火性を発揮できるものと期待されている。
しかし、燃焼室内に強い筒内気流が形成されていると、チャンバーから噴射されたプラズマ状態となった電離気体が混合気と反応して形成された火炎核が十分な大きさに燃焼成長しないうちに、この気流に流されて燃焼速度の低下を招き、不安定な着火となる虞がある。
また、燃焼室内に直接高圧燃料が噴射される直噴式内燃機関の点火にプラズマ点火装置を用いた場合、特に低温始動時においては、噴射された燃料が液滴状に凝縮して付着し、チャンバー開口部が塞がれてプラズマ状態となった電離気体の噴射が抑制されたり、放電経路に燃料の液滴が滞留することによって放電電圧の上昇を招いたりして、不安定な着火となる虞もある。 In the plasma ignition device as in Patent Document 3, by applying a high voltage and supplying a large current in the chamber, the gas in the chamber is ionized and injected into a high-temperature and high-pressure plasma state. It is expected to be able to demonstrate high ignitability.
However, if a strong in-cylinder airflow is formed in the combustion chamber, the ionized gas in the plasma state injected from the chamber reacts with the air-fuel mixture and the flame kernel formed is not sufficiently grown and grown. In addition, the airflow may cause a decrease in the combustion speed, resulting in unstable ignition.
In addition, when a plasma ignition device is used for ignition of a direct injection internal combustion engine in which high pressure fuel is directly injected into the combustion chamber, the injected fuel is condensed and attached in droplets, particularly at low temperature start, and the chamber There is a risk of unstable ignition due to suppression of the injection of ionized gas that has been blocked due to the opening being blocked, or fuel droplets staying in the discharge path, leading to an increase in discharge voltage. There is also.

そこで、本発明は、かかる実情に鑑み、内燃機関の主燃焼室に連通する副燃焼室内から主燃焼室内に火炎を噴射させて点火を行う副燃焼室式点火装置であって、難着火性内燃機関においても優れた着火性を発揮すると共に、液体燃料の付着によって失火の起こり難い信頼性の高い副燃焼室式点火装置の提供を目的とするものである。   Therefore, in view of such circumstances, the present invention is a sub-combustion chamber type ignition device that performs ignition by injecting flame from a sub-combustion chamber communicating with a main combustion chamber of an internal combustion engine into the main combustion chamber. An object of the present invention is to provide a highly reliable sub-combustion chamber type ignition device that exhibits excellent ignitability even in an engine and is unlikely to cause misfire due to adhesion of liquid fuel.

本発明では、内燃機関の主燃焼室に連通する副燃焼室から主燃焼室内に火炎を噴射させて点火を行う副燃焼室点火装置であって、
上記内燃機関の運転状況に応じた点火信号を発信する電子制御装置と、
該電子制御装置から発信された点火信号にしたがって、電源から供給された電気エネルギをレーザ光に変換して発振するレーザ発振器と、
先端側に副燃焼室が区画され、該副燃焼室の底部近傍に主燃焼室に連通する複数の連通孔が穿設された副燃焼室付レーザ点火プラグとからなり、
該副燃焼室付レーザ点火プラグが、
上記レーザ発振器から発振されたレーザ光を、上記複数の連通孔の内の上記副燃焼室の底部の中心軸に対して上記主燃焼室の特定の位置に向かう方向に穿設せしめた特定の連通孔に近い位置に集光するように、上記副燃焼室の容積重心よりも先端側で、かつ、上記連通孔の穿設された特定の方向へ偏心せしめた位置に焦点を設定した集光手段を具備し、上記主燃焼室内の特定の位置に火炎を噴射させることを特徴とする（請求項１）。 In the present invention, a sub-combustion chamber ignition device that performs ignition by injecting a flame into a main combustion chamber from a sub-combustion chamber communicating with a main combustion chamber of an internal combustion engine,
An electronic control device for transmitting an ignition signal according to the operating condition of the internal combustion engine;
A laser oscillator that oscillates by converting electric energy supplied from a power source into laser light in accordance with an ignition signal transmitted from the electronic control unit;
A sub-combustion chamber with a sub-combustion chamber, the sub-combustion chamber is partitioned on the tip side, and a plurality of communication holes communicating with the main combustion chamber are formed near the bottom of the sub-combustion chamber;
The laser ignition plug with a secondary combustion chamber is
A specific communication in which laser light oscillated from the laser oscillator is drilled in a direction toward a specific position of the main combustion chamber with respect to the central axis of the bottom of the sub-combustion chamber among the plurality of communication holes. Condensing means with a focal point set at a position decentered in a specific direction in which the communication hole is bored and on the tip side of the volumetric center of gravity of the sub-combustion chamber so as to collect light at a position close to the hole And a flame is injected to a specific position in the main combustion chamber (claim 1).

本発明によれば、上記内燃機関の圧縮行程において、上記副燃焼室内に導入された混合気に、上記電子制御装置の点火信号にしたがって上記レーザ発振器から発振されたレーザ光が上記集光手段によって、上記副燃焼室の容積重心よりも先端側の連通孔に近い位置にレーザ光が集光され、その位置を起爆点として、副燃焼室内の混合気が着火され、副燃焼室内の未燃混合気あるいは燃焼気体低温部に次々と引火し、燃焼気体高温部が燃焼成長しながら容積を拡大し、その一部が上記連通孔を通って主燃焼室内に噴出する。
このとき、燃焼成長が進む過程で燃焼気体の高温部が上記連通孔から上記主燃焼室内に噴射され、上記副燃焼室内に導入された混合気のうち、未燃焼部分が上記燃焼気体の高温部よりも先に上記主燃焼室内に噴出することもない。
さらに、上記主燃焼室内に強力な筒内気流が発生していても、上記副燃焼室内に発生した燃焼気体の高温部に直接触れることはないので、燃焼初期に火炎が消失する虞がなく、適度に燃焼成長し安定した状態で主燃焼内に噴射されることになる。
加えて、上記複数の連通孔の内の特定の連通孔から上記主燃焼室のノッキングを発生し易い特定の位置に向かって火炎を噴射させることが可能となり、ノッキングを抑制し、さらに信頼性の高い副燃焼室式点火装置が実現できる。
したがって、着火性に優れ、信頼性の高い副燃焼室点火装置が実現できる。 According to the present invention, in the compression stroke of the internal combustion engine, the air-fuel mixture introduced into the auxiliary combustion chamber, the laser beam oscillated from the laser oscillator in accordance with an ignition signal of the electronic control unit by said focusing means The laser beam is condensed at a position closer to the communication hole on the tip side than the volume center of gravity of the sub-combustion chamber, and the air-fuel mixture in the sub-combustion chamber is ignited with that position as the initiation point, and unburned mixture in the sub-combustion chamber The gas or combustion gas low temperature portion is ignited one after another, and the combustion gas high temperature portion expands in volume while burning and growing, and a part thereof is ejected into the main combustion chamber through the communication hole.
At this time, in the process of combustion growth , the high temperature portion of the combustion gas is injected into the main combustion chamber from the communication hole, and the unburned portion of the air-fuel mixture introduced into the sub combustion chamber is the high temperature portion of the combustion gas. It does not spout into the main combustion chamber earlier than the above.
Furthermore, even if a strong in-cylinder airflow is generated in the main combustion chamber, it does not directly touch the high temperature part of the combustion gas generated in the subcombustion chamber, so there is no risk of the flame disappearing in the early stage of combustion, It will be injected into the main combustion in a stable state with moderate growth.
In addition, it becomes possible to inject a flame from a specific communication hole of the plurality of communication holes toward a specific position where the knocking of the main combustion chamber is likely to occur. A high auxiliary combustion chamber type ignition device can be realized.
Therefore, a highly reliable auxiliary combustion chamber ignition device can be realized.

第２の発明によれば、上記主燃焼室内に上記複数の連通孔から火炎が噴射されるので、点火タイミングのバラツキが生じても、上記主燃焼室内の燃料リッチな部分への燃焼気体の高温部が噴出され接触する確率が高くなり、より安定した点火の実現も期待できる。 According to the second invention, since the flame is injected from the plurality of communication holes into the main combustion chamber, the high temperature of the combustion gas to the fuel-rich portion in the main combustion chamber is generated even if the ignition timing varies. The probability that the part is ejected and contacted is increased, and more stable ignition can be expected.

第３の発明によれば、上記主燃焼室のノッキングを発生し易い特定の位置に向かって火炎を噴射させることが可能となり、ノッキングを抑制し、さらに信頼性の高い副燃焼室式点火装置が実現できる。 According to the third invention, it is possible to inject a flame toward a specific position where the knocking of the main combustion chamber is likely to occur, to suppress knocking, and to provide a highly reliable auxiliary combustion chamber type ignition device. realizable.

本発明の第１の実施形態における点火装置の概要を示す断面図。Sectional drawing which shows the outline | summary of the ignition device in the 1st Embodiment of this invention. 本発明の副燃焼室式点火装置の実施例における効果を示し、（ａ）は、圧縮行程における要部断面図、（ｂ）は、点火時の状態を示す要部断面図。The effect in the Example of the subcombustion chamber type ignition device of the present invention is shown, (a) is a principal section sectional view in a compression stroke, and (b) is a principal section sectional view showing the state at the time of ignition. 比較例として示す従来の副燃焼室式点火装置の問題点を示し、（ａ）は、圧縮行程における要部断面図、（ｂ）は、点火時の状態を示す要部断面図。The problem of the conventional subcombustion chamber type ignition device shown as a comparative example is shown, (a) is principal part sectional drawing in a compression stroke, (b) is principal part sectional drawing which shows the state at the time of ignition. 本発明の効果を確認するために用いた試験装置の概要を示し、（ａ）は、上面から見た半断面図、（ｂ）は、側面から見た半断面図。The outline | summary of the test apparatus used in order to confirm the effect of this invention is shown, (a) is a half sectional view seen from the upper surface, (b) is a half sectional view seen from the side. 本発明の実施例における効果を示す図面代用シュリーレン写真。The drawing substitute schlieren photograph which shows the effect in the Example of this invention. 比較例における図面代用シュリーレン写真。Drawing substitute schlieren photograph in comparative example. 比較例と共に示す本発明の効果を示す特性図。The characteristic view which shows the effect of this invention shown with a comparative example. 本発明の第２の実施形態における副燃焼室式点火装置の概要を示す断面図。Sectional drawing which shows the outline | summary of the auxiliary combustion chamber type ignition device in the 2nd Embodiment of this invention. 本発明の第３の実施形態における副燃焼室式点火装置の概要を示し、（ａ）は全体図、（ｂ）は要部断面図。The outline | summary of the auxiliary combustion chamber type ignition device in the 3rd Embodiment of this invention is shown, (a) is a general view, (b) is principal part sectional drawing. 本発明の第４の実施形態における副燃焼室式点火装置の概要を示し、（ａ）は全体図、（ｂ）は要部断面図。 The outline | summary of the auxiliary combustion chamber type ignition device in the 4th Embodiment of this invention is shown, (a) is a general view, (b) is principal part sectional drawing .

本発明の副燃焼室式点火装置は、自動車エンジン等の内燃機関の点火に使用され、副燃焼室内の混合気を効率よく燃焼させ、主燃焼室内にトーチ状の火炎を噴射して、内燃機関の点火を行うものである。   The auxiliary combustion chamber type ignition device of the present invention is used for ignition of an internal combustion engine such as an automobile engine, and efficiently burns an air-fuel mixture in the auxiliary combustion chamber and injects a torch-like flame into the main combustion chamber. The ignition is performed.

本発明の第１の実施形態における点火装置１について、図１を参照して説明する。なお、以下の説明において、図の上方を基端側、下方を先端側と称す。
本実施形態における点火装置１は、自動車エンジン等の内燃機関５０の点火に用いられ、点火手段として、レーザ光を集光して火炎核を発生させると共に、先端側には、内燃機関５０の主燃焼室５００と連通孔１１１を介して連通する副燃焼室１００が区画され、副燃焼室１００内の容積重心よりも連通孔１１１に近い位置において起爆点ＦＰが発生するようにレーザ光を集光して、点火後早期に高温の火炎を副燃焼室１００内に形成し、連通孔１１１から主燃焼室５００内に噴射して内燃機関５０の点火を行う副燃焼室付レーザ点火プラグ１０を有することを最大の特徴としている。 An ignition device 1 according to a first embodiment of the present invention will be described with reference to FIG. In the following description, the upper side of the figure is referred to as the proximal end side, and the lower side is referred to as the distal end side.
The ignition device 1 according to the present embodiment is used to ignite an internal combustion engine 50 such as an automobile engine. As an ignition means, a laser beam is condensed to generate a flame nucleus, and a main part of the internal combustion engine 50 is disposed on the tip side. The sub-combustion chamber 100 communicating with the combustion chamber 500 via the communication hole 111 is partitioned, and the laser beam is collected so that the initiation point FP is generated at a position closer to the communication hole 111 than the center of gravity of the volume in the sub-combustion chamber 100. Then, a high temperature flame is formed in the auxiliary combustion chamber 100 at an early stage after ignition, and the auxiliary ignition chamber-equipped laser ignition plug 10 that ignites the internal combustion engine 50 by injecting it into the main combustion chamber 500 from the communication hole 111 is provided. This is the biggest feature.

点火装置１は、点火手段である副燃焼室付レーザ点火プラグ１０と、副燃焼室付レーザ点火プラグ１０にエネルギを供給する高エネルギ供給手段であり、電源２０から供給された電気エネルギをレーザ光に変換して発振するレーザ発振器３０と、内燃機関５０の運転状況に応じて、レーザ発振器３０を駆動制御する電子制御装置ＥＣＵ４０とによって構成されている。イグニションスイッチ２１が入れられると車載バッテリ、オルタネータ等の電源２０からレーザ発振器３０にエネルギが供給されると共に運転状況に応じた点火信号がＥＣＵ３０から発信される。   The ignition device 1 is a laser spark plug 10 with an auxiliary combustion chamber, which is an ignition means, and high energy supply means for supplying energy to the laser ignition plug 10 with an auxiliary combustion chamber, and the electric energy supplied from the power source 20 is converted into laser light. A laser oscillator 30 that oscillates after being converted to an electronic control unit and an electronic control unit ECU 40 that controls the drive of the laser oscillator 30 according to the operating state of the internal combustion engine 50 are configured. When the ignition switch 21 is turned on, energy is supplied from a power source 20 such as an in-vehicle battery or an alternator to the laser oscillator 30 and an ignition signal corresponding to the operating condition is transmitted from the ECU 30.

副燃焼室付レーザ点火プラグ１０は、有底筒状に形成されたハウジング１２０を具備し、ハウジング１２０の外周に形成されたネジ部１２１等によって、内燃機関５０のシリンダヘッド５１に穿設されたプラグホール５４０に先端側が主燃焼室５００に露出するように固定されている。   The laser ignition plug 10 with a sub-combustion chamber includes a housing 120 formed in a bottomed cylindrical shape, and is drilled in the cylinder head 51 of the internal combustion engine 50 by a screw portion 121 or the like formed on the outer periphery of the housing 120. The plug hole 540 is fixed so that the tip side is exposed to the main combustion chamber 500.

ハウジング１２０の基端側には、レーザ発振器３０から発振されたレーザ光が導入される光ファイバ等のレーザ光伝送手段３３が設けられている。
ハウジング１２０内には、ハウジング１２０の先端側に区画された副燃焼室１００内の所定の位置にレーザ光を集光する集光手段３４が載置されている。
集光手段３４の先端側には、レーザ光を透過しつつ、集光手段３４を保護する保護カバー３５が載置されている。
ハウジング１２０の先端側には、主燃焼室５００側に向かって略半球状に膨出する底部１１０が形成され、ハウジング１２０の内周と保護カバー３４と底部１１０とによって所定の容積を有する副燃焼室１００が区画されている。
ハウジング１２０の底部１１０には、主燃焼室５００と副燃焼室１００とを連通する連通孔１１１が穿設されている。 On the base end side of the housing 120, laser light transmission means 33 such as an optical fiber into which the laser light oscillated from the laser oscillator 30 is introduced is provided.
In the housing 120, a condensing unit 34 that condenses the laser light is placed at a predetermined position in the auxiliary combustion chamber 100 defined on the front end side of the housing 120.
A protective cover 35 that protects the condensing unit 34 while transmitting the laser beam is placed on the front end side of the condensing unit 34.
A bottom portion 110 that swells in a substantially hemispherical shape toward the main combustion chamber 500 side is formed on the front end side of the housing 120. Chamber 100 is partitioned.
A communication hole 111 for communicating the main combustion chamber 500 and the sub-combustion chamber 100 is formed in the bottom portion 110 of the housing 120.

なお、本発明において、レーザ発振器３０を限定するものではなく、内燃機関の点火に利用可能な公知のレーザ発振器を適宜採用し得るものである。
例えば、レーザ発振器３０は、半導体レーザ等のレーザ媒質と、このレーザ媒質にエネルギを与え励起する励起源とからなるレーザ発振源３１と、発振されたレーザ光を増幅するレーザ増幅部３２とを含んでいる。
レーザ媒質として、半導体レーザ、固体レーザ等を用いることができる。
また、レーザ増幅部は、シャッタ素子（Ｑスイッチ）と、反射鏡と、出力鏡とを具備し、励起用半導体レーザから発振されたレーザ光により、固体レーザとシャッタ素子が共に励起され、シャッタ素子内のエネルギが、そのシャッタ素子自身の物性によって決定されるある閾値を超えた瞬間にシャッタが開き、レーザ光が反射鏡と出力鏡との間を往復する毎に共振し、増幅され、瞬間的にエネルギ密度の高いレーザ光を取り出すことができる。 In the present invention, the laser oscillator 30 is not limited, and a known laser oscillator that can be used for ignition of the internal combustion engine can be appropriately employed.
For example, the laser oscillator 30 includes a laser oscillation source 31 including a laser medium such as a semiconductor laser, an excitation source that excites and applies energy to the laser medium, and a laser amplification unit 32 that amplifies the oscillated laser light. It is out.
As the laser medium, a semiconductor laser, a solid laser, or the like can be used.
The laser amplifying unit includes a shutter element (Q switch), a reflecting mirror, and an output mirror, and both the solid-state laser and the shutter element are excited by laser light oscillated from the pumping semiconductor laser. The shutter opens at the moment when the energy in the lens exceeds a certain threshold determined by the physical properties of the shutter element itself, and resonates and amplifies each time the laser beam reciprocates between the reflecting mirror and the output mirror. In addition, a laser beam having a high energy density can be extracted.

内燃機関５０は、シリンダヘッド５１と略筒状のシリンダ５２とシリンダ５２内を自在に昇降するピストン５３とによって構成され、シリンダヘッド５１の内壁とシリンダ５２の内周壁とピストン５３の頂面とによって主燃焼室５００が区画されている。
シリンダヘッド５１には、吸気筒５１０と排気筒５２０とが設けられ、それぞれ吸気バルブ５１１と排気バルブ５２１とによって開閉されている。
主燃焼室５００内に吸気筒５１０から導入された空気と図略の燃料噴射装置によって燃料室５００内に供給された燃料とが混合され、ピストン５３によって主燃焼室５００内の混合気が圧縮されると、連通孔１１１を通って副燃焼室１００内に混合気が圧入される。
所定のクランク角においてＥＣＵ３０から発信される点火信号にしたがって、レーザ発振器３０からレーザ光が発振され、集光手段３４によって副燃焼室１００内の所定の位置に定められた起爆点ＦＰにおいて極めて高いエネルギ密度に集光され、副燃焼室１００内の混合気が着火され、高温ガスが連通孔１１１の近くで発生し、この高温ガスの成長と共に、連通孔１１１を通って主燃焼室５００内に噴射され、主燃焼室５００内の混合気の燃焼・爆発が誘発され、主燃焼室５００内の圧力ＰＣＹＬが一気に上昇し、その圧力によってピストン５３が押下げられ内燃機関５０の動力が得られる。
なお、内燃機関５０の主燃焼室５００内にはタンブル渦等の強い筒内気流ＴＭＢが形成されている。 The internal combustion engine 50 includes a cylinder head 51, a substantially cylindrical cylinder 52, and a piston 53 that freely moves up and down in the cylinder 52, and includes an inner wall of the cylinder head 51, an inner peripheral wall of the cylinder 52, and a top surface of the piston 53. A main combustion chamber 500 is defined.
The cylinder head 51 is provided with an intake cylinder 510 and an exhaust cylinder 520, which are opened and closed by an intake valve 511 and an exhaust valve 521, respectively.
The air introduced from the intake cylinder 510 into the main combustion chamber 500 and the fuel supplied into the fuel chamber 500 by a fuel injection device (not shown) are mixed, and the air-fuel mixture in the main combustion chamber 500 is compressed by the piston 53. Then, the air-fuel mixture is pressed into the auxiliary combustion chamber 100 through the communication hole 111.
Laser light is oscillated from the laser oscillator 30 in accordance with an ignition signal transmitted from the ECU 30 at a predetermined crank angle, and extremely high energy is generated at the initiation point FP determined at a predetermined position in the sub-combustion chamber 100 by the light collecting means 34. Concentrated in the density, the air-fuel mixture in the auxiliary combustion chamber 100 is ignited, and hot gas is generated near the communication hole 111, and is injected into the main combustion chamber 500 through the communication hole 111 as the hot gas grows. Then, combustion / explosion of the air-fuel mixture in the main combustion chamber 500 is induced, the pressure P CYL in the main combustion chamber 500 rises at once, and the piston 53 is pushed down by the pressure, and the power of the internal combustion engine 50 is obtained.
A strong in-cylinder airflow TMB such as a tumble vortex is formed in the main combustion chamber 500 of the internal combustion engine 50.

ここで、図２及び図３を参照し、本発明の副燃焼室点火装置１を用いて、副燃焼室１００の容積重心よりも先端側に近づいた位置を起爆点ＦＰとする実施例と、副燃焼室１００の容積重心よりも基端側に離れた位置を起爆点ＦＰｚとする比較例との燃焼速度の違いについて説明する。   Here, referring to FIG. 2 and FIG. 3, using the auxiliary combustion chamber ignition device 1 of the present invention, an embodiment in which the position closer to the tip side than the center of gravity of the auxiliary combustion chamber 100 is used as the initiation point FP, A difference in combustion speed from the comparative example in which the position farther from the base end side than the volume center of gravity of the auxiliary combustion chamber 100 is set as the initiation point FPz will be described.

図２（ａ）に示すように、本実施形態における副燃焼室式点火装置１では、副燃焼室１００の容積重心Ｇよりも先端側の連通孔１１１に近い位置にレーザ光が集光されるように集光手段３４の焦点を設定してある。
内燃機関５０の圧縮行程において、ピストン５３の上昇に伴い、主燃焼室５００内の混合気の一部が連通孔１１１を通って副燃焼室１００内に導入される。
ＥＣＵ４０の点火信号にしたがって発振されたレーザ光が集光手段３４によって副燃焼室１００内に集光され、図２（ｂ）に示すように、副燃焼室１００の容積重心Ｇよりも先端側の連通孔１１１に近い位置を起爆点ＦＰとして、副燃焼室１００内の混合気が着火され、副燃焼室１００内の未燃混合気あるいは燃焼気体低温部ＬＧに次々と引火し、燃焼気体高温部ＨＧ１が燃焼成長しながら容積を拡大し、その一部ＨＧ２が連通孔１１１を通って主燃焼室５００内に噴出する。
このとき、主燃焼室５００内に強力な筒内気流ＴＭＢが発生していても、副燃焼室１００内に発生した燃焼気体高温部ＨＧ１に直接触れることはないので、燃焼初期に火炎が消失する虞がなく、適度に燃焼成長し安定した状態で主燃焼室５００内に噴射されることになる。 As shown in FIG. 2A, in the auxiliary combustion chamber type ignition device 1 in the present embodiment, the laser beam is condensed at a position closer to the communication hole 111 on the tip side than the volume gravity center G of the auxiliary combustion chamber 100. Thus, the focal point of the light collecting means 34 is set.
In the compression stroke of the internal combustion engine 50, as the piston 53 rises, a part of the air-fuel mixture in the main combustion chamber 500 is introduced into the auxiliary combustion chamber 100 through the communication hole 111.
The laser light oscillated according to the ignition signal of the ECU 40 is condensed in the sub-combustion chamber 100 by the condensing means 34, and as shown in FIG. With the position close to the communication hole 111 as an initiation point FP, the air-fuel mixture in the auxiliary combustion chamber 100 is ignited, and the unburned air-fuel mixture in the auxiliary combustion chamber 100 or the combustion gas low temperature part LG is ignited one after another, and the combustion gas high temperature part The volume of the HG 1 is expanded while being combusted and grown, and a part of the HG 2 is ejected into the main combustion chamber 500 through the communication hole 111.
At this time, even if generated strong cylinder airflow TMB into the main combustion chamber 500, since no direct contact with the combustion gas temperature portion HG 1 generated in the auxiliary combustion chamber 100, a combustion initial flame is lost There is no fear of this, and it will be injected into the main combustion chamber 500 in a stable state with a moderate growth of growth.

一方、比較例においては、図３（ａ）に示すように、レーザ光の集光位置が連通孔１１１に対して副燃焼室１００内の容積重心Ｇよりも基端側に離れている。このような構成においては、ＥＣＵ４０の点火信号にしたがって発振されたレーザ光が集光手段３４ｚによって副燃焼室１００ｚ内に集光されたときに、図２（ｂ）に示すように、副燃焼室１００の容積重心Ｇよりも基端側の連通孔１１１ｚから離れた位置を起爆点ＦＰｚとして、副燃焼室１００ｚ内の混合気の着火が起こる。このため、点火直後においては連通孔１１１ｚからは、燃焼気体高温部ＨＧｚが噴出されることなく、その外側に存在する未燃混合気や燃焼気体低温部ＬＧｚが噴出される。したがって、副燃焼室１００ｚ内で燃焼成長が進み主燃焼室５００内に燃焼気体高温部ＨＧｚが噴出するまでの時間が長くなり、燃焼バラツキを生じ易くなる。
さらに、副燃焼室１００ｚ内で燃焼成長するときに燃焼気体高温部ＨＧｚによって未燃混合気が先に押し出されてしまうため副燃焼室１００ｚ内で発生する熱エネルギの総量が低下して失火に至る虞もある。 On the other hand, in the comparative example, as shown in FIG. 3A, the condensing position of the laser beam is farther from the communication hole 111 toward the base end side than the volume gravity center G in the auxiliary combustion chamber 100. In such a configuration, when the laser light oscillated in accordance with the ignition signal of the ECU 40 is condensed in the auxiliary combustion chamber 100z by the condensing means 34z, as shown in FIG. The air-fuel mixture in the sub-combustion chamber 100z is ignited with a position away from the communication hole 111z on the base end side with respect to the volume gravity center G of 100 as an initiation point FPz. For this reason, immediately after ignition, the combustion gas high-temperature part HGz is not ejected from the communication hole 111z, but the unburned gas mixture and the combustion gas low-temperature part LGz existing outside thereof are ejected. Therefore, the combustion growth proceeds in the sub-combustion chamber 100z, and the time until the combustion gas high-temperature portion HGz is ejected into the main combustion chamber 500 becomes longer, and combustion variations are likely to occur.
Further, when combustion growth occurs in the auxiliary combustion chamber 100z, the unburned gas mixture is pushed out first by the combustion gas high temperature portion HGz, so that the total amount of heat energy generated in the auxiliary combustion chamber 100z is reduced, leading to misfire. There is also a fear.

ここで、本発明の効果を検証するために行った試験について、図４、図５、図６を参照して説明する。図４に示す試験装置は、内燃機関５０のシリンダヘッド５１を模した蓋部５１ａと、シリンダ５２を模した筒部５２ａと、ピストン５３を模した底部５３ａとによって、燃焼室５００を模した燃焼室５００ａを区画し、耐圧性の圧力容器５０ａとから構成されている。
筒部５２ａの側面に点火時の様子を観察すべく耐圧性の観察窓を設けてある。
蓋部５１ａには、ハウジング１２０を模して、略半円柱状の溝を穿設した上側ブロック１２０ａと、底部１１０を模して、略半円柱状の溝を穿設した下側ブロック１１０ａとを合わせて副燃焼室１００を模して一定容量の副燃焼室１００ａを区画し、副燃焼室１００ａの両側面には、耐圧性の観察窓が設けてある。
さらに、上側ブロック１２０ａの中心には、レーザ式発振装置３０から発振され集光手段３４、３４ｚによって副燃焼室１００ａ内の所定の位置に集光するための略円柱状の孔が穿設されている。
下側ブロック１１０ａの中心には、連通孔１１１を模して副燃焼室１００ａと主燃焼室５００ａとを連通する連通孔１１１ａが穿設されている。蓋部５１の中心には、本発明の副燃焼室式点火装置１を模して副燃焼室１００ａの容積重心Ｇよりも先端側に集光する集光手段３５、又は比較例として示した従来の副燃焼室式点火装置１ｚを模して副燃焼室１００ａの容積重心Ｇよりも基端側に集光する集光手段３５ｚを固定するためのプラグホール５４０ａが穿設されている。
圧力容器５０ａには、図略の燃料供給装置が接続され所定圧力で燃料が導入され、さらに図略の圧力調整装置が接続され所定圧力の圧縮空気が導入され、圧力容器５０ａ内は所定の空燃比及び圧力に調整できる。 Here, a test performed to verify the effect of the present invention will be described with reference to FIGS. 4, 5, and 6. The test apparatus shown in FIG. 4 is a combustion simulating a combustion chamber 500 by a lid part 51a simulating a cylinder head 51 of an internal combustion engine 50, a cylinder part 52a simulating a cylinder 52, and a bottom part 53a simulating a piston 53. The chamber 500a is partitioned and is composed of a pressure-resistant pressure vessel 50a.
A pressure-resistant observation window is provided on the side surface of the cylindrical portion 52a in order to observe the ignition state.
The lid 51a has an upper block 120a in which a substantially semi-cylindrical groove is drilled, imitating the housing 120, and a lower block 110a in which a substantially semi-cylindrical groove is drilled in the bottom 110. A sub-combustion chamber 100a having a constant capacity is partitioned by simulating the sub-combustion chamber 100, and pressure-resistant observation windows are provided on both side surfaces of the sub-combustion chamber 100a.
Further, a substantially cylindrical hole is formed in the center of the upper block 120a to oscillate from the laser oscillation device 30 and to collect light at a predetermined position in the auxiliary combustion chamber 100a by the light collecting means 34 and 34z. Yes.
In the center of the lower block 110a, a communication hole 111a that communicates the sub-combustion chamber 100a and the main combustion chamber 500a is formed in a manner similar to the communication hole 111. At the center of the lid portion 51, the condensing means 35 for condensing the auxiliary combustion chamber type ignition device 1 of the present invention on the tip side with respect to the volume gravity center G of the auxiliary combustion chamber 100 a, or the conventional example shown as a comparative example. A plug hole 540a for fixing the condensing means 35z for condensing light toward the base end side with respect to the volume center of gravity G of the sub-combustion chamber 100a is formed so as to imitate the sub-combustion chamber type ignition device 1z.
A fuel supply device (not shown) is connected to the pressure vessel 50a and fuel is introduced at a predetermined pressure. Further, a pressure adjustment device (not shown) is connected and compressed air of a predetermined pressure is introduced, and the pressure vessel 50a has a predetermined empty space. Adjustable to fuel ratio and pressure.

圧力容器５０ａ内にプロパンと空気とを用いて混合比Ａ／Ｆ＝１２．８の割合で混合した混合気を導入し、主燃焼室５００ａ内の圧力が２気圧となるよう調整し、レーザ発振器３０によって、波長λ５３２ｎｍ、ビーム径φ４ｍｍ、焦点距離２２ｍｍ、エネルギ２０ｍＪのレーザ光を発振し、上述した実施例の起爆点ＦＰと比較例の起爆点ＦＰｚとに対応する位置にレーザ光を集光させ、点火から１．０ｍｓ後の状態をシュリーレン撮影し、その結果をそれぞれ図５、図６に示す。   A gas mixture mixed at a ratio of A / F = 12.8 using propane and air is introduced into the pressure vessel 50a, and adjusted so that the pressure in the main combustion chamber 500a becomes 2 atm. 30 oscillates a laser beam having a wavelength of λ532 nm, a beam diameter of 4 mm, a focal length of 22 mm, and an energy of 20 mJ, and condenses the laser beam at a position corresponding to the initiation point FP of the above-described embodiment and the initiation point FPz of the comparative example. The state after 1.0 ms after ignition was shot with Schlieren, and the results are shown in FIGS. 5 and 6, respectively.

図５に示すように、本発明の実施例を模して副燃焼室１００ａと主燃焼室５００ａとを連通する連通孔１１１ａに近い位置に起爆点ＦＰを設定した場合、起爆点ＦＰの周囲に形成された火炎を含む燃焼気体高温部ＨＧ１が形成され、連通孔１１１ａから主燃焼室５００ａ内に燃焼気体高温部ＨＧ２が噴射されることが確認された。 As shown in FIG. 5, when the initiation point FP is set at a position close to the communication hole 111 a that communicates the sub-combustion chamber 100 a and the main combustion chamber 500 a by simulating the embodiment of the present invention, the initiation point FP is set around the initiation point FP. burnt gas temperature portion HG1 containing the formed flame is formed, the combustion gas temperature portion HG 2 was confirmed to be injected into the main combustion chamber 500a from the communication hole 111a.

一方、図６に示すように、比較例を模して副燃焼室１００ａと主燃焼室５００ａとを連通する連通孔１１１ａから離れた位置に起爆点ＦＰｚを設定した場合、起爆点ＦＰｚの周囲に火炎を含む燃焼気体高温部ＨＧｚが形成されるものの、連通孔１１１ａからは燃焼気体高温部ＨＧｚは噴射されず、燃焼気体高温部ＨＧｚの燃焼拡大に伴って、その周囲の未燃焼混合又は燃焼気体低温部ＬＧｚの一部が燃焼されることなく排出されてしまうので、燃焼気体高温部ＨＧｚの燃焼拡大速度が低下し、連通孔１１１ａから噴出されるまでの時間が遅れることが確認された。   On the other hand, as shown in FIG. 6, when the initiation point FPz is set at a position away from the communication hole 111 a that communicates the sub-combustion chamber 100 a and the main combustion chamber 500 a in a similar manner to the comparative example, around the initiation point FPz. Although the combustion gas high-temperature part HGz including the flame is formed, the combustion gas high-temperature part HGz is not injected from the communication hole 111a, and as the combustion gas high-temperature part HGz expands, the surrounding unburned mixture or combustion gas Since a part of the low temperature part LGz is discharged without being combusted, it is confirmed that the combustion expansion speed of the combustion gas high temperature part HGz is reduced and the time until the gas is ejected from the communication hole 111a is delayed.

さらに、本発明の第１の実施形態に示した副燃焼室式点火装置１を用いた場合における主燃焼室５００内の圧力ＰＣＹＬの変化と、比較例に示した副燃焼室式点火装置１ｚを用いた場合における主燃焼室５００内の圧力ＰＣＹＬの変化とを測定し、その結果を図７に示す。
図７に示すように、比較例は主燃焼室５００内の圧力ＰＣＹＬ上昇に遅れが生じ、本発明の実施例の方が早期に主燃焼室内の圧力ＰＣＹＬが上昇し良好な着火性を実現できることが確認された。 Furthermore, the change in the pressure P CYL in the main combustion chamber 500 when the sub-combustion chamber ignition device 1 shown in the first embodiment of the present invention is used, and the sub-combustion chamber ignition device 1z shown in the comparative example. 7 is used to measure the change in the pressure P CYL in the main combustion chamber 500, and the result is shown in FIG.
As shown in FIG. 7, in the comparative example, there is a delay in the rise of the pressure P CYL in the main combustion chamber 500, and in the embodiment of the present invention, the pressure P CYL in the main combustion chamber rises earlier and has good ignitability. It was confirmed that it could be realized.

図８を参照して本発明の第２の実施形態における副燃焼室式点火装置１ｂについて説明する。なお、本実施形態において、上記実施形態と同様の構成については、同じ符号を付したので説明を省略し、相違点についてのみ説明をする（以下の実施形態についても同様とする）。
本実施形態においては、燃料噴射弁６０を用いて副燃焼室１００ｂ内に直接燃料を噴射し、副燃焼室１００ｂ内の空燃比をリッチとし、主燃焼室５００内の空燃比をリーンとすることによって、さらに着火性を向上させることも可能となる。
また、このような構成とすることによって全体の空燃比としてはよりリーンとしてさらなる燃費の向上を図ることも可能となると期待される。 An auxiliary combustion chamber ignition device 1b according to the second embodiment of the present invention will be described with reference to FIG. In addition, in this embodiment, since the same code | symbol is attached | subjected about the structure similar to the said embodiment, description is abbreviate | omitted and only a different point is demonstrated (it is the same also about the following embodiment).
In the present embodiment, fuel is directly injected into the auxiliary combustion chamber 100b using the fuel injection valve 60, the air-fuel ratio in the auxiliary combustion chamber 100b is made rich, and the air-fuel ratio in the main combustion chamber 500 is made lean. Thus, it becomes possible to further improve the ignitability.
In addition, it is expected that the fuel efficiency can be further improved by making the overall air-fuel ratio leaner by adopting such a configuration.

図９を参照して本発明の第３の実施形態における副燃焼室式点火装置１ｃについて説明する。本実施形態においては、燃料噴射弁６０ｃを主燃焼室５００内に燃料ＦＬを直接噴射する位置に設けてある。さらに、副燃焼室１００ｃの底部１１０ｃには、副燃焼室１００ｃ内で形成された燃焼気体高温部ＨＧを噴出する連通孔１１１に加えて、燃料噴射弁６０ｃから噴射された燃料ＦＬを副燃焼室５００ｃ内に導入する燃料導入用連通孔１１２ｃが穿設されている。
このような構成とすることによって副燃焼室５００ｃ内への燃料ＦＬの導入を容易にし、副燃焼室５００ｃ内の空燃比をリッチにして着火を容易となる。さらに、副燃焼室５００ｃ自体が保護カバー３５を保護する覆いの役割を果たし、燃料ＦＬの液滴が直接保護カバー３５を汚染することがないため安定して副燃焼室５００ｃ内の所定の位置にレーザ光が集光される。したがって、副燃焼室式点火装置の信頼性がさらに向上する。 A sub-combustion chamber ignition device 1c according to a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the fuel injection valve 60c is provided at a position where the fuel FL is directly injected into the main combustion chamber 500. Further, in the bottom 110c of the auxiliary combustion chamber 100c, in addition to the communication hole 111 for injecting the combustion gas high temperature part HG formed in the auxiliary combustion chamber 100c, the fuel FL injected from the fuel injection valve 60c is supplied to the auxiliary combustion chamber 100c. A fuel introduction communication hole 112c to be introduced into 500c is formed.
Such a configuration facilitates the introduction of the fuel FL into the sub-combustion chamber 500c, makes the air-fuel ratio in the sub-combustion chamber 500c rich, and facilitates ignition. Further, the auxiliary combustion chamber 500c itself serves as a cover for protecting the protective cover 35, and since the droplets of the fuel FL do not directly contaminate the protective cover 35, the auxiliary combustion chamber 500c is stably placed in a predetermined position in the auxiliary combustion chamber 500c. Laser light is collected. Therefore, the reliability of the auxiliary combustion chamber ignition device is further improved.

図１０を参照して本発明の第４の実施形態における副燃焼室式点火装置１ｄについて説明する。本実施形態においては、副燃焼室１００ｄ内に形成された燃焼気体高温部ＨＧを主燃焼室５００内の特定の方向に噴射させるように、副燃焼室付レーザ点火プラグ１０ｄをシリンダ５２の中心軸に対して斜めに配設してある。
このような構成とすることによって、図１０（ａ）に示すように、燃料噴射弁６０ｄから噴射された燃料ＦＬによって連通孔１１１ｄが汚染されるのを抑制すると共に、図１１（ｂ）に示すように点火時には、主燃焼室５００内のノッキングの発生しやすい特定の位置に向けて燃焼気体高温部ＨＧを優先的に噴射させ、ノッキングを抑制することも可能となる。
さらに、底部１１０ｄに複数の連通孔１１１ｄ、１１２ｄが穿設されていても、集光手段３５ｄを副燃焼室５００ｄの中心軸からズレ対置で集光するように配設すると共に連通孔１１１ｄを底部中心から偏心させた位置に穿設することによって、起爆点ＦＰｄを特定の連通孔１１１ｄに近づけることが可能となり、選択的に連通孔１１１ｄから燃焼気体高温部ＨＧを噴射させることもできる。 A sub-combustion chamber ignition device 1d according to a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the auxiliary combustion chamber-attached laser spark plug 10d is placed in the central axis of the cylinder 52 so that the combustion gas high temperature portion HG formed in the auxiliary combustion chamber 100d is injected in a specific direction in the main combustion chamber 500. It is arrange | positioned diagonally with respect to.
By adopting such a configuration, as shown in FIG. 10A, the communication hole 111d is prevented from being contaminated by the fuel FL injected from the fuel injection valve 60d, and shown in FIG. 11B. Thus, at the time of ignition, it is possible to preferentially inject the combustion gas high temperature part HG toward a specific position in the main combustion chamber 500 where knocking is likely to occur, thereby suppressing knocking.
Further, even if a plurality of communication holes 111d and 112d are formed in the bottom portion 110d, the light collecting means 35d is disposed so as to condense the light from the central axis of the auxiliary combustion chamber 500d and the communication hole 111d is provided at the bottom portion. By drilling at a position that is eccentric from the center, the initiation point FPd can be brought closer to the specific communication hole 111d, and the combustion gas high temperature part HG can be selectively injected from the communication hole 111d.

なお、本発明は上記実施形態に限定するものではなく、点火手段として先端側に副燃焼室が区画され、該副燃焼室の底部近傍に主燃焼室に連通する少なくとも１つ以上の連通孔が穿設された副燃焼室付点火手段と、該副燃焼室付点火手段に電源から供給される電気エネルギを高エネルギに変換して供給する高エネルギ供給手段と、内燃機関の運転状況に応じた点火信号を発信して上記高エネルギ供給手段の駆動を制御する電子制御装置と、を具備し、副燃焼室付点火手段の起爆点を副燃焼室の容積重心よりも連通孔に近い位置となすことによって、副燃焼室から効率よく高温ガスを主燃焼室内に噴射させ着火性の向上を図る本発明の趣旨を逸脱しない範囲において適宜変更可能である。   The present invention is not limited to the above-described embodiment, and a sub-combustion chamber is defined on the tip side as ignition means, and at least one communication hole communicating with the main combustion chamber is provided near the bottom of the sub-combustion chamber. According to the operating conditions of the internal combustion engine, the ignition means with the auxiliary combustion chamber provided, the high energy supply means that converts the electric energy supplied from the power source to the ignition means with the auxiliary combustion chamber and converts it into high energy An electronic control unit that controls the drive of the high energy supply means by transmitting an ignition signal, and sets the ignition point of the ignition means with the auxiliary combustion chamber to a position closer to the communication hole than the center of gravity of the volume of the auxiliary combustion chamber. Thus, the temperature can be changed as appropriate without departing from the spirit of the present invention in which high temperature gas is efficiently injected from the auxiliary combustion chamber into the main combustion chamber to improve the ignitability.

１ 副燃焼室式点火装置
１０ 副燃焼室付レーザ点火プラグ（副燃焼室付点火手段）
１００ 副燃焼室
１１０ 底部
１１１ 連通孔
２０ 電源
３０ レーザ発振器（高エネルギ供給手段）
４０ ＥＣＵ（電子制御装置）
５０ 内燃機関
５００ 主燃焼室
ＦＰ 起爆点（集光点）
Ｇ 副燃焼室容積重心 1 Sub-combustion chamber type ignition device 10 Laser ignition plug with sub-combustion chamber (ignition means with sub-combustion chamber)
100 Sub Combustion Chamber 110 Bottom 111 Communication Hole 20 Power Supply 30 Laser Oscillator (High Energy Supply Means)
40 ECU (electronic control unit)
50 Internal combustion engine 500 Main combustion chamber FP Explosion point (condensing point)
G Secondary combustion chamber volume center of gravity

特開２００７−１９２２０４号公報JP 2007-192204 A 特開２００５−４２５９１号公報JP 2005-42591 A 特開２００６−２９４２５７号公報JP 2006-294257 A

Claims (1)

内燃機関の主燃焼室に連通する副燃焼室から主燃焼室内に火炎を噴射させて点火を行う副燃焼室点火装置であって、
上記内燃機関の運転状況に応じた点火信号を発信する電子制御装置と、
該電子制御装置から発信された点火信号にしたがって、電源から供給された電気エネルギをレーザ光に変換して発振するレーザ発振器と、
先端側に副燃焼室が区画され、該副燃焼室の底部近傍に主燃焼室に連通する複数の連通孔が穿設された副燃焼室付レーザ点火プラグとからなり、
該副燃焼室付レーザ点火プラグが、
上記レーザ発振器から発振されたレーザ光を、上記複数の連通孔の内の上記副燃焼室の底部の中心軸に対して上記主燃焼室の特定の位置に向かう方向に穿設せしめた特定の連通孔に近い位置に集光するように、上記副燃焼室の容積重心よりも先端側で、かつ、上記連通孔の穿設された特定の方向へ偏心せしめた位置に焦点を設定した集光手段を具備し、上記主燃焼室内の特定の位置に火炎を噴射させることを特徴とする副燃焼室式点火装置。 A sub-combustion chamber ignition device that performs ignition by injecting a flame into a main combustion chamber from a sub-combustion chamber communicating with a main combustion chamber of an internal combustion engine,
An electronic control device for transmitting an ignition signal according to the operating condition of the internal combustion engine;
A laser oscillator that oscillates by converting electric energy supplied from a power source into laser light in accordance with an ignition signal transmitted from the electronic control unit;
A sub-combustion chamber with a sub-combustion chamber, the sub-combustion chamber is partitioned on the tip side, and a plurality of communication holes communicating with the main combustion chamber are formed near the bottom of the sub-combustion chamber;
The laser ignition plug with a secondary combustion chamber is
A specific communication in which laser light oscillated from the laser oscillator is drilled in a direction toward a specific position of the main combustion chamber with respect to the central axis of the bottom of the sub-combustion chamber among the plurality of communication holes. Condensing means with a focal point set at a position decentered in a specific direction in which the communication hole is bored and on the tip side of the volumetric center of gravity of the sub-combustion chamber so as to collect light at a position close to the hole And a sub-combustion chamber type igniter characterized by injecting a flame at a specific position in the main combustion chamber .
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