JP2004251195A - Gas engine - Google Patents

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Publication number
JP2004251195A
JP2004251195A JP2003042312A JP2003042312A JP2004251195A JP 2004251195 A JP2004251195 A JP 2004251195A JP 2003042312 A JP2003042312 A JP 2003042312A JP 2003042312 A JP2003042312 A JP 2003042312A JP 2004251195 A JP2004251195 A JP 2004251195A
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Japan
Prior art keywords
combustion chamber
main combustion
water injection
water
sub
Prior art date
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Pending
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JP2003042312A
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Japanese (ja)
Inventor
Maki Iwamura
真樹 岩村
Ryosuke Tsujisaki
良輔 辻前
Hiroto Itagaki
弘人 板垣
Shigeru Ito
茂 伊藤
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IHI Corp
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IHI Corp
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Priority to JP2003042312A priority Critical patent/JP2004251195A/en
Publication of JP2004251195A publication Critical patent/JP2004251195A/en
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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
    • 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
    • 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
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas engine capable of sufficiently reducing NOx. <P>SOLUTION: This gas engine is provided with a main combustion chamber 16 formed in a cylinder 13 to obtain a driving output by burning the lean gas supplied from the outside, an auxiliary combustion chamber 18 communicating with the main combustion chamber 16 to ignite with the pressure by injection of the pilot fuel P, and a water injection means 24 for injecting water to lower the combustion temperature of the main combustion chamber 16. When burning the fuel gas in the main combustion chamber 16, the water injection means 24 injects water to lower the combustion temperature of the main combustion chamber 16 to sufficiently reduce NOx to be generated by a rise of the combustion temperature. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、副燃焼室内にパイロット燃料を噴射して圧力により着火する方式を採用したガスエンジンに関するものである。
【０００２】
【従来の技術】
従来、エンジンには、シリンダとシリンダヘッドを組み合わせてピストンを駆動可能にする主燃焼室を形成すると共に、主燃焼室に連通孔を介して連通するようシリンダヘッドに小容積の副燃焼室を設け、更に副燃焼室に、パイロット燃料を噴射するパイロット油弁を配置したものがある。このようなエンジンより駆動出力を得る際には、副燃焼室にパイロット油弁からパイロット燃料を供給して圧縮・自着火させ、副燃室の燃焼ガスを主燃焼室に広げることにより、主燃焼室内の燃料ガスを燃焼してピストン等を介し駆動出力を得ている。
【０００３】
しかしながら、このようなエンジンは、希薄混合気の燃焼であるがゆえに、強力な点火を付与させないと、燃焼変動を起して燃料の高濃度の部分が形成され、ＮＯｘが発生するという問題がある。又、エネルギー熱効率が低いという問題があった。
【０００４】
このため、近年のエンジンには、低ＮＯｘを維持しながら高いエンジン熱効率を得るよう、図３に示す如く、主燃焼室４に連通孔５を介して連通するようシリンダヘッド２に小容積の副燃焼室６を設けたものがある。ここで、図中、１はシリンダ、３はピストン、７は副燃焼室６に配置されたパイロット油弁、８は燃料の希薄ガスを供給する吸気ポート、９は主燃焼室４内の排ガスを排気する排気ポート、１０は吸気弁、１１は排気弁を、夫々示している。ここで、副燃焼室６を備えたガスエンジンに関しては、例えば、次の特許文献１等において開示がなされている。
【０００５】
【特許文献１】
特開平１１−３２４８０５号公報
【０００６】
【発明が解決しようとする課題】
しかしながら、近年、環境汚染への対策として排ガス規制が厳しくなっており、上記の如く副燃焼室６においてパイロット燃料Ｐの噴射により圧力で着火させるように構成しても、ＮＯｘは燃焼温度の上昇で増加するため、ＮＯｘの低減が十分でないという問題があった。
【０００７】
本発明は上述の実情に鑑み、ＮＯｘを十分に低減し得るガスエンジンを提供することを目的としたものである。
【０００８】
【課題を解決するための手段】
本発明の請求項１は、外部より供給された希薄ガスを燃焼して駆動出力を得るようシリンダ内に形成された主燃焼室と、該主燃焼室に連通してパイロット燃料の噴射により圧力で着火を起こす副燃焼室と、前記主燃焼室の燃焼温度を下げるよう水を噴霧し得る水噴射手段とを備えたことを特徴とするガスエンジン、に係るものである。
【０００９】
本発明の請求項２は、吸気ポートより供給された希薄ガスを燃焼して駆動出力を得るようシリンダ内に形成された主燃焼室と、該主燃焼室に連通してパイロット燃料の噴射により圧力で着火を起こす副燃焼室と、前記主燃焼室の燃焼温度を下げるよう前記吸気ポートに水を噴霧し得る水噴射手段とを備えたことを特徴とするガスエンジン、に係るものである。
【００１０】
本発明の請求項３は、水噴射手段を水噴射弁にした請求項１又は２記載のガスエンジン、に係るものである。
【００１１】
本発明の請求項４は、水噴射手段をキャブレタにした請求項１又は２記載のガスエンジン、に係るものである。
【００１２】
請求項１〜４によれば、水噴射手段を備えるので、副燃焼室の着火によって主燃焼室の燃料ガスを燃焼する際には、水噴射手段より水を噴霧して主燃焼室の燃焼温度を下げ、結果的に、燃焼温度の上昇で発生するＮＯｘを十分に低減することができる。
【００１３】
又、請求項２によれば、吸気ポートに水噴射手段を備えるので、主燃焼室に燃料を供給した際には、水噴射手段より噴射された水が吸気ポートの風速により均等に分散し、主燃焼室の燃焼温度を一層均等に下げ、結果的に、燃焼温度の上昇で発生するＮＯｘを更に低減することができる。
【００１４】
請求項３に示す如く、水噴射手段を水噴射弁にすると、正確な量の水を噴霧すると共に噴霧のタイミングを調整し得るので、主燃焼室の燃焼温度を好適に下げ、ＮＯｘを更に低減することができる。
【００１５】
請求項４に示す如く、水噴射手段をキャブレタにすると、簡易な構成で水を噴霧し得るので、ＮＯｘを低減する構成を安価に製造することができる。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。
【００１７】
図１は、本発明のガスエンジンを実施する形態の第一例である。
【００１８】
第一例のガスエンジンは、シリンダ１３とシリンダヘッド１４を組み合わせてピストン１５を駆動可能にする主燃焼室１６を形成すると共に、主燃焼室１６に連通孔１７を介して連通するようシリンダヘッド１４に小容積の副燃焼室１８を設けており、主燃焼室１６には、燃料の希薄ガスを吸気弁１９を介して供給する吸気ポート２０と、排ガスを排気弁２１を介して排気する排気ポート２２とを接続し、副燃焼室１８にはパイロット油弁２３のみを配置している。又、シリンダヘッド１４には、エンジンが冷えている状態で主燃焼室１６の燃料に着火するための始動用点火プラグ（図示せず）を備えている。
【００１９】
吸気ポート２０の吸気弁１９より上流位置には、水噴射手段の水噴射弁２４を備えており、水噴射弁２４は、吸気弁１９の動きと連動するように適当なタイミングで少量の水を噴霧するように構成されている。ここで、水噴射弁２４のノズルは、水を少量で噴射するスロットル行程を備えたスロットル型、ニードルバルブの押し上げ等により水を噴射するホース型でもよいし、他の形状でもよい。又、水の噴霧量は、主燃焼室１６及び副燃焼室１８の容積や、燃料の希薄ガスの濃度等に対して、適切な割合になるように調整されており、更に既存の電子制御式の噴射弁を使用可能にしている。
【００２０】
以下、本発明のガスエンジンを実施する形態の第一例の作用を説明する。
【００２１】
エンジンより駆動出力を得る際には、吸気ポート２０の吸気弁１９の駆動に伴って主燃焼室１６に燃料の希薄ガスを供給して副燃焼室１８に希薄ガスを流入させ、続いて、副燃焼室１８にパイロット油弁２３から低濃度のパイロット燃料Ｐを噴射することにより圧力で強力な着火を起し、副燃焼室１８の着火を主燃焼室１６に広げることにより、主燃焼室１６内の希薄ガスを燃焼してピストン１５等を介し駆動出力を得る。
【００２２】
ここで、吸気ポート２０の吸気弁１９の駆動に伴って主燃焼室１６に燃料の希薄ガスを供給する際には、同時若しくは適切なタイミングで水噴射手段の水噴射弁２４より少量の水を噴霧しており、噴霧された水は吸気ポート２０の風速に伴われて分散しつつ主燃焼室１６に流れ込み、希薄ガスによる主燃焼室１６内の燃焼温度を低下させる。ここで、主燃焼室１６への水の噴霧は、副燃焼室１８内での強力な着火により、主燃焼室１６内での希薄ガスの燃焼の障害となることがない。
【００２３】
このように、第一例によれば、水噴射手段の水噴射弁２４を備えるので、副燃焼室１８の着火によって主燃焼室１６の希薄ガスを燃焼する際には、水噴射手段の水噴射弁２４より水を噴霧して主燃焼室１６の燃焼温度を下げ、結果的に、燃焼温度の上昇で発生するＮＯｘを十分に低減することができる。なお、副燃焼室１８に従来例の如くパイロット油弁と点火プラグとを備えて着火した場合には、ＮＯｘの濃度が高くなると共に、パイロット燃料Ｐの噴射による圧力での着火に比べて着火力が弱くなり、水の噴霧に対応することができない。
【００２４】
又、吸気ポート２０に水噴射手段の水噴射弁２４を備えるので、主燃焼室１６に燃料を供給した際には、水噴射手段の水噴射弁２４より噴射された水が吸気ポート２０の風速により均等に分散し、主燃焼室１６の燃焼温度を一層均等に下げるので、燃焼温度の上昇で発生するＮＯｘを更に低減することができる。
【００２５】
更に、水噴射手段を水噴射弁２４にすると、正確な量の水を噴霧すると共に噴霧のタイミングを調整し得るので、主燃焼室１６の燃焼温度を好適に下げ、燃焼温度の上昇で発生するＮＯｘを更に低減することができる。
【００２６】
図２は、本発明のガスエンジンを実施する形態の第二例である。
【００２７】
第二例のガスエンジンは、シリンダ２５とシリンダヘッド２６を組み合わせてピストン２７を駆動可能にする主燃焼室２８を形成すると共に、主燃焼室２８に連通孔２９を介して連通するようシリンダヘッド２６に小容積の副燃焼室３０を設けており、主燃焼室２８には、燃料の希薄ガスを吸気弁３１を介して供給する吸気ポート３２と、排ガスを排気弁３３を介して排気する排気ポート３４とを接続し、副燃焼室３０にはパイロット油弁３５のみを配置している。又、シリンダヘッド２６には、エンジンが冷えている状態で主燃焼室２８の燃料に着火するための始動用点火プラグ（図示せず）を備えている。
【００２８】
吸気ポート３２の吸気弁３１より上流位置には、水噴射手段のキャブレタ３６を備えており、キャブレタ３６は、吸気ポート３２の流路が急激に狭くなるようなベンチュリ部３７を形成すると共に、ベンチュリ部３７で生じる流速の負圧により水を噴霧させるノズル３８を備えている。ここで、キャブレタ３６は、ベンチュリ部３７の径を固定した固定ベンチュリや、ベンチュリピストン等によりベンチュリ部３７の径を可変する可変ベンチュリでもよいし、ベンチュリ部３７と吸気弁３１の間に流速を変化させるスロットバルブを配してもよいし、他の構成でもよい。又、水の噴霧量は、主燃焼室２８及び副燃焼室３０の容積や、燃料の希薄ガスの濃度等に対して、適切な割合になるように調整されている。
【００２９】
以下、本発明のガスエンジンを実施する形態の第二例の作用を説明する。
【００３０】
エンジンより駆動出力を得る際には、第一例と略同様に、吸気ポート３２の吸気弁３１の駆動に伴って主燃焼室２８に燃料の希薄ガスを供給して副燃焼室３０に希薄ガスを流入させ、続いて、副燃焼室３０にパイロット油弁３５から低濃度のパイロット燃料Ｐを噴射することにより圧力で強力な着火を起し、副燃焼室３０の着火を主燃焼室２８に広げることにより、主燃焼室２８内の希薄ガスを燃焼してピストン２７等を介し駆動出力を得る。
【００３１】
ここで、吸気ポート３２の吸気弁の駆動に伴って主燃焼室２８に燃料の希薄ガスを供給する際には、同時若しくは適切なタイミングで水噴射手段のキャブレタ３６のノズル３８より少量の水を噴霧しており、噴霧された水は吸気ポート３２の風速に伴われて分散しつつ主燃焼室２８に流れ込み、希薄ガスによる主燃焼室２８内の燃焼温度を低下させる。ここで、主燃焼室２８への水の噴霧は、副燃焼室３０内での強力な着火により、主燃焼室２８内での希薄ガスの燃焼の障害となることがない。
【００３２】
このように、第二例によれば、水噴射手段のキャブレタ３６を備えるので、副燃焼室３０の着火によって主燃焼室２８の希薄ガスを燃焼する際には、水噴射手段の水噴射弁２４より水を噴霧して主燃焼室２８の燃焼温度を下げ、結果的に、燃焼温度の上昇で発生するＮＯｘを十分に低減することができる。なお、副燃焼室３０に従来例の如くパイロット油弁と点火プラグとを備えて着火した場合には、ＮＯｘの濃度が高くなると共に、パイロット燃料Ｐの噴射による圧力での着火に比べて着火力が弱くなり、水の噴霧に対応することができない。
【００３３】
又、吸気ポート３２に水噴射手段のキャブレタ３６を備えるので、主燃焼室２８に燃料を供給した際には、水噴射手段の水噴射弁２４より噴射された水が吸気ポート３２の風速により均等に分散し、主燃焼室２８の燃焼温度を一層均等に下げるので、燃焼温度の上昇で発生するＮＯｘを更に低減することができる。
【００３４】
更に、水噴射手段をキャブレタ３６にすると、簡易な構成で水を噴霧し得るので、ＮＯｘを低減する構成を安価に製造することができる。
【００３５】
なお、本発明のガスエンジンは上述の形態例のみに限定されるものではなく、水噴射手段をシリンダ内に設けて主燃焼室に水を直接噴霧してもよいこと、水噴射手段は上記の例に限定されるものではないこと、その他、本発明の要旨を逸脱しない範囲内において種々変更を加え得ることは勿論である。
【００３６】
【発明の効果】
本発明のガスエンジンによれば、水噴射手段を備えるので、副燃焼室の着火によって主燃焼室の燃料ガスを燃焼する際には、水噴射手段より水を噴霧して主燃焼室の燃焼温度を下げ、結果的に、燃焼温度の上昇で発生するＮＯｘを十分に低減することができるという優れた効果を奏し得る。
【図面の簡単な説明】
【図１】本発明のガスエンジンを実施する形態の第一例を示す概略図である。
【図２】本発明のガスエンジンを実施する形態の第二例を示す概略図である。
【図３】従来のガスエンジンを示す概略図である。
【符号の説明】
１３ シリンダ
１６ 主燃焼室
１８ 副燃焼室
２０ 吸気ポート（外部）
２４ 水噴射弁（水噴射手段）
２５ シリンダ
２８ 主燃焼室
３０ 副燃焼室
３２ 吸気ポート（外部）
３６ キャブレタ（水噴射手段）
Ｐ パイロット燃料[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas engine adopting a system in which pilot fuel is injected into a sub-combustion chamber to ignite by pressure.
[0002]
[Prior art]
Conventionally, an engine forms a main combustion chamber that enables driving of a piston by combining a cylinder and a cylinder head, and a small-volume sub-combustion chamber is provided in the cylinder head so as to communicate with the main combustion chamber through a communication hole. In addition, there is another type in which a pilot oil valve for injecting pilot fuel is disposed in the auxiliary combustion chamber. When a drive output is obtained from such an engine, pilot fuel is supplied to the sub-combustion chamber from a pilot oil valve, compressed and self-ignited, and the combustion gas in the sub-combustion chamber is spread to the main combustion chamber, thereby achieving main combustion. The driving output is obtained via the piston and the like by burning the fuel gas in the room.
[0003]
However, since such an engine burns a lean air-fuel mixture, if a strong ignition is not provided, there is a problem that a combustion variation occurs, a high-concentration portion of fuel is formed, and NOx is generated. . In addition, there is a problem that energy heat efficiency is low.
[0004]
Therefore, in order to obtain high engine thermal efficiency while maintaining low NOx in recent engines, as shown in FIG. 3, a small-volume sub-tube is connected to the main combustion chamber 4 via the communication hole 5 so as to communicate with the main combustion chamber 4. Some include a combustion chamber 6. Here, in the figure, 1 is a cylinder, 3 is a piston, 7 is a pilot oil valve arranged in a sub-combustion chamber 6, 8 is an intake port for supplying a lean gas of fuel, and 9 is an exhaust gas in the main combustion chamber 4. An exhaust port 10 for exhausting the air, an intake valve 10, and an exhaust valve 11. Here, a gas engine provided with the sub-combustion chamber 6 is disclosed in, for example, the following Patent Document 1.
[0005]
[Patent Document 1]
JP-A-11-324805
[Problems to be solved by the invention]
However, in recent years, exhaust gas regulations have become strict as a measure against environmental pollution, and even if the sub-combustion chamber 6 is ignited by pressure by injecting the pilot fuel P in the sub-combustion chamber 6 as described above, NOx is generated due to an increase in combustion temperature. Because of the increase, there was a problem that the reduction of NOx was not sufficient.
[0007]
The present invention has been made in view of the above circumstances, and has as its object to provide a gas engine capable of sufficiently reducing NOx.
[0008]
[Means for Solving the Problems]
A first aspect of the present invention is directed to a main combustion chamber formed in a cylinder for obtaining a drive output by burning a lean gas supplied from the outside, and communicating with the main combustion chamber by pressure of pilot fuel injection. The present invention relates to a gas engine comprising: a sub-combustion chamber that causes ignition; and water injection means that can spray water so as to lower the combustion temperature of the main combustion chamber.
[0009]
According to a second aspect of the present invention, there is provided a main combustion chamber formed in a cylinder for obtaining a drive output by burning a lean gas supplied from an intake port, and a pressure generated by injection of pilot fuel in communication with the main combustion chamber. The present invention relates to a gas engine comprising: a sub-combustion chamber that ignites at a pressure; and water injection means that can spray water to the intake port so as to lower the combustion temperature of the main combustion chamber.
[0010]
A third aspect of the present invention relates to the gas engine according to the first or second aspect, wherein the water injection means is a water injection valve.
[0011]
Claim 4 of the present invention relates to the gas engine according to claim 1 or 2, wherein the water injection means is a carburetor.
[0012]
According to claims 1 to 4, since the water injection means is provided, when fuel gas in the main combustion chamber is burned by ignition of the sub-combustion chamber, water is sprayed from the water injection means and the combustion temperature of the main combustion chamber is increased. As a result, NOx generated by an increase in combustion temperature can be sufficiently reduced.
[0013]
According to the second aspect, since the water injection means is provided in the intake port, when the fuel is supplied to the main combustion chamber, the water injected from the water injection means is evenly dispersed by the wind speed of the intake port, The combustion temperature in the main combustion chamber can be more evenly reduced, and as a result, NOx generated by an increase in the combustion temperature can be further reduced.
[0014]
When the water injection means is a water injection valve, an accurate amount of water can be sprayed and the timing of spraying can be adjusted, so that the combustion temperature of the main combustion chamber is suitably lowered and NOx is further reduced. can do.
[0015]
As described in claim 4, when the water injection means is a carburetor, water can be sprayed with a simple configuration, so that a configuration for reducing NOx can be manufactured at low cost.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 shows a first embodiment of a gas engine according to the present invention.
[0018]
In the gas engine of the first example, a cylinder 13 and a cylinder head 14 are combined to form a main combustion chamber 16 capable of driving a piston 15, and the cylinder head 14 is connected to the main combustion chamber 16 via a communication hole 17. A small-volume sub-combustion chamber 18 is provided in the main combustion chamber 16. An intake port 20 for supplying a lean gas of fuel through an intake valve 19 and an exhaust port for exhausting exhaust gas through an exhaust valve 21 are provided in the main combustion chamber 16. 22 and only the pilot oil valve 23 is disposed in the sub-combustion chamber 18. The cylinder head 14 is provided with a starting spark plug (not shown) for igniting fuel in the main combustion chamber 16 when the engine is cold.
[0019]
At a position upstream of the intake valve 19 of the intake port 20, a water injection valve 24 of water injection means is provided. The water injection valve 24 supplies a small amount of water at an appropriate timing so as to interlock with the movement of the intake valve 19. It is configured to spray. Here, the nozzle of the water injection valve 24 may be a throttle type having a throttle stroke for injecting a small amount of water, a hose type for injecting water by pushing up a needle valve, or other shapes. Further, the spray amount of water is adjusted so as to have an appropriate ratio with respect to the volumes of the main combustion chamber 16 and the sub-combustion chamber 18, the concentration of the lean gas of the fuel, and the like. Of the injection valves can be used.
[0020]
Hereinafter, the operation of the first example of the embodiment of the gas engine of the present invention will be described.
[0021]
When a drive output is obtained from the engine, a lean gas of fuel is supplied to the main combustion chamber 16 with the driving of the intake valve 19 of the intake port 20 to flow the lean gas into the sub-combustion chamber 18. By injecting low-concentration pilot fuel P from the pilot oil valve 23 into the combustion chamber 18, a strong ignition is caused by pressure, and the ignition of the sub-combustion chamber 18 is extended to the main combustion chamber 16, whereby the main combustion chamber 16 Is burned to obtain a drive output via the piston 15 or the like.
[0022]
Here, when the lean gas of the fuel is supplied to the main combustion chamber 16 with the driving of the intake valve 19 of the intake port 20, a small amount of water is supplied from the water injection valve 24 of the water injection means simultaneously or at an appropriate timing. The atomized water is sprayed and flows into the main combustion chamber 16 while being dispersed according to the wind speed of the intake port 20, and lowers the combustion temperature in the main combustion chamber 16 due to the lean gas. Here, the spray of water to the main combustion chamber 16 does not hinder the combustion of the lean gas in the main combustion chamber 16 due to the strong ignition in the sub-combustion chamber 18.
[0023]
Thus, according to the first example, since the water injection valve 24 of the water injection unit is provided, when the lean gas in the main combustion chamber 16 is burned by the ignition of the sub-combustion chamber 18, the water injection of the water injection unit is performed. Water is sprayed from the valve 24 to lower the combustion temperature of the main combustion chamber 16, and as a result, NOx generated due to an increase in the combustion temperature can be sufficiently reduced. When the sub-combustion chamber 18 is ignited with a pilot oil valve and a spark plug as in the conventional example, the NOx concentration becomes high and the ignition power is lower than the ignition by the pressure by the injection of the pilot fuel P. Becomes weak and cannot respond to water spray.
[0024]
Further, since the intake port 20 is provided with the water injection valve 24 of the water injection means, when the fuel is supplied to the main combustion chamber 16, the water injected from the water injection valve 24 of the water injection means is subjected to the wind speed of the intake port 20. And the combustion temperature of the main combustion chamber 16 is reduced more evenly, so that the NOx generated by the increase in the combustion temperature can be further reduced.
[0025]
Further, when the water injection means is the water injection valve 24, it is possible to spray an accurate amount of water and adjust the timing of spraying, so that the combustion temperature of the main combustion chamber 16 is suitably lowered and the combustion temperature is increased. NOx can be further reduced.
[0026]
FIG. 2 shows a second embodiment of the embodiment of the gas engine of the present invention.
[0027]
In the gas engine of the second example, a cylinder 25 and a cylinder head 26 are combined to form a main combustion chamber 28 capable of driving a piston 27, and a cylinder head 26 is connected to the main combustion chamber 28 through a communication hole 29. The main combustion chamber 28 has an intake port 32 for supplying a lean gas of fuel through an intake valve 31 and an exhaust port for exhausting exhaust gas through an exhaust valve 33. 34, and only the pilot oil valve 35 is disposed in the sub-combustion chamber 30. The cylinder head 26 is provided with a starting spark plug (not shown) for igniting fuel in the main combustion chamber 28 when the engine is cold.
[0028]
At a position upstream of the intake valve 31 of the intake port 32, a carburetor 36 of water injection means is provided. The carburetor 36 forms a venturi portion 37 in which the flow path of the intake port 32 is rapidly narrowed. A nozzle 38 for spraying water by a negative pressure of the flow velocity generated in the section 37 is provided. Here, the carburetor 36 may be a fixed venturi in which the diameter of the venturi section 37 is fixed, a variable venturi in which the diameter of the venturi section 37 is changed by a venturi piston or the like, or the carburetor 36 changes the flow velocity between the venturi section 37 and the intake valve 31. A slot valve may be provided, or another configuration may be used. The spray amount of water is adjusted so as to have an appropriate ratio with respect to the volumes of the main combustion chamber 28 and the sub-combustion chamber 30, the concentration of the lean gas of the fuel, and the like.
[0029]
Hereinafter, the operation of the second example of the embodiment of the gas engine of the present invention will be described.
[0030]
When the drive output is obtained from the engine, the lean gas of the fuel is supplied to the main combustion chamber 28 with the driving of the intake valve 31 of the intake port 32 and the lean gas is supplied to the sub-combustion chamber 30 in substantially the same manner as in the first example. Then, by injecting low-concentration pilot fuel P from the pilot oil valve 35 into the sub-combustion chamber 30, strong ignition is caused by pressure, and the ignition of the sub-combustion chamber 30 is spread to the main combustion chamber 28. Thus, the lean gas in the main combustion chamber 28 is burned to obtain a drive output via the piston 27 and the like.
[0031]
Here, when supplying the lean gas of the fuel to the main combustion chamber 28 with the driving of the intake valve of the intake port 32, a small amount of water is supplied from the nozzle 38 of the carburetor 36 of the water injection means at the same time or at an appropriate timing. The sprayed water is sprayed and flows into the main combustion chamber 28 while being dispersed according to the wind speed of the intake port 32, and lowers the combustion temperature in the main combustion chamber 28 by the lean gas. Here, the spraying of water into the main combustion chamber 28 does not hinder the combustion of the lean gas in the main combustion chamber 28 due to the strong ignition in the sub-combustion chamber 30.
[0032]
Thus, according to the second example, since the carburetor 36 of the water injection unit is provided, when the lean gas in the main combustion chamber 28 is burned by the ignition of the sub-combustion chamber 30, the water injection valve 24 of the water injection unit is used. By spraying more water, the combustion temperature of the main combustion chamber 28 is lowered, and as a result, NOx generated by the increase in the combustion temperature can be sufficiently reduced. When the sub-combustion chamber 30 is ignited with a pilot oil valve and a spark plug as in the conventional example, the concentration of NOx is increased and the ignition power is lower than the ignition by the pressure by the injection of the pilot fuel P. Becomes weak and cannot respond to water spray.
[0033]
Further, since the intake port 32 is provided with the carburetor 36 of the water injection means, when the fuel is supplied to the main combustion chamber 28, the water injected from the water injection valve 24 of the water injection means is more evenly distributed by the wind speed of the intake port 32. And the combustion temperature in the main combustion chamber 28 is reduced more uniformly, so that the NOx generated by the increase in the combustion temperature can be further reduced.
[0034]
Further, when the carburetor 36 is used as the water injection means, water can be sprayed with a simple configuration, so that a configuration for reducing NOx can be manufactured at low cost.
[0035]
In addition, the gas engine of the present invention is not limited to the above-described embodiment only. The water injection means may be provided in the cylinder to spray water directly to the main combustion chamber. It is needless to say that the present invention is not limited to the examples, and that various changes can be made without departing from the scope of the present invention.
[0036]
【The invention's effect】
According to the gas engine of the present invention, since the water injection means is provided, when the fuel gas in the main combustion chamber is burned by the ignition of the sub-combustion chamber, water is sprayed from the water injection means to burn the combustion temperature of the main combustion chamber. As a result, it is possible to obtain an excellent effect that NOx generated by an increase in combustion temperature can be sufficiently reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a first embodiment of a gas engine according to the present invention.
FIG. 2 is a schematic view showing a second example of the embodiment of the gas engine according to the present invention.
FIG. 3 is a schematic view showing a conventional gas engine.
[Explanation of symbols]
13 Cylinder 16 Main combustion chamber 18 Sub combustion chamber 20 Intake port (external)
24 water injection valve (water injection means)
25 Cylinder 28 Main combustion chamber 30 Sub combustion chamber 32 Intake port (external)
36 Carburetor (water injection means)
P pilot fuel

Claims (4)

外部より供給された希薄ガスを燃焼して駆動出力を得るようシリンダ内に形成された主燃焼室と、該主燃焼室に連通してパイロット燃料の噴射により圧力で着火を起こす副燃焼室と、前記主燃焼室の燃焼温度を下げるよう水を噴霧し得る水噴射手段とを備えたことを特徴とするガスエンジン。A main combustion chamber formed in a cylinder to obtain a drive output by burning a lean gas supplied from the outside, a sub-combustion chamber communicating with the main combustion chamber and igniting by pressure by injection of pilot fuel, A gas injection means for spraying water so as to lower the combustion temperature of the main combustion chamber. 吸気ポートより供給された希薄ガスを燃焼して駆動出力を得るようシリンダ内に形成された主燃焼室と、該主燃焼室に連通してパイロット燃料の噴射により圧力で着火を起こす副燃焼室と、前記主燃焼室の燃焼温度を下げるよう前記吸気ポートに水を噴霧し得る水噴射手段とを備えたことを特徴とするガスエンジン。A main combustion chamber formed in the cylinder so as to obtain a drive output by burning the lean gas supplied from the intake port, and a sub-combustion chamber which communicates with the main combustion chamber and ignites by pressure by injection of pilot fuel. Water injection means for spraying water to the intake port so as to lower the combustion temperature of the main combustion chamber. 水噴射手段を水噴射弁にした請求項１又は２記載のガスエンジン。3. The gas engine according to claim 1, wherein the water injection means is a water injection valve. 水噴射手段をキャブレタにした請求項１又は２記載のガスエンジン。3. The gas engine according to claim 1, wherein the water injection means is a carburetor.
JP2003042312A 2003-02-20 2003-02-20 Gas engine Pending JP2004251195A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007113461A (en) * 2005-10-19 2007-05-10 Fuji Seratekku Kk Gas engine improving ignitability of fuel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007113461A (en) * 2005-10-19 2007-05-10 Fuji Seratekku Kk Gas engine improving ignitability of fuel

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