JP5072765B2 - Spark ignition gas fuel internal combustion engine - Google Patents

Spark ignition gas fuel internal combustion engine Download PDF

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JP5072765B2
JP5072765B2 JP2008200480A JP2008200480A JP5072765B2 JP 5072765 B2 JP5072765 B2 JP 5072765B2 JP 2008200480 A JP2008200480 A JP 2008200480A JP 2008200480 A JP2008200480 A JP 2008200480A JP 5072765 B2 JP5072765 B2 JP 5072765B2
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intake
gas fuel
passage
valve
control valve
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JP2010038003A (en
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廣満 松本
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Yamaha 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
    • 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
    • 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
    • Y02T10/40—Engine management systems

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  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Description

本発明は、水素，ＣＮＧ，プロパン，ブタン等を燃料とする火花点火式ガス燃料内燃機関に関する。   The present invention relates to a spark ignition gas fuel internal combustion engine using hydrogen, CNG, propane, butane or the like as fuel.

この種のガス燃料内燃機関では、スロットル弁により吸入空気量を、ガス燃料供給弁により燃料供給量を調整することにより出力制御を行うようにしている。またこの種の内燃機関では、気筒内に横渦又は縦渦の吸気渦流を生成させるために、吸気通路に、前記スロットル弁をバイパスするようにバイパス通路を設ける場合がある（例えば、特許文献１参照）。
特許第３５５７３１４号 In this type of gas fuel internal combustion engine, output control is performed by adjusting the intake air amount by a throttle valve and the fuel supply amount by a gas fuel supply valve. In this type of internal combustion engine, in order to generate a lateral vortex or vertical vortex intake vortex flow in a cylinder, a bypass passage may be provided in the intake passage so as to bypass the throttle valve (for example, Patent Document 1). reference).
Japanese Patent No. 3557314

ところで、前記従来の内燃機関では、スロットル弁が略全閉状態の部分負荷運転域においては、吸気通路内は負圧が維持されることから、ポンピング損失が生じるという問題がある。   By the way, in the conventional internal combustion engine, in the partial load operation region where the throttle valve is substantially fully closed, a negative pressure is maintained in the intake passage, so that there is a problem that a pumping loss occurs.

本発明は、前記従来の状況に鑑みてなされたもので、部分負荷運転域での吸気通路の負圧を低減することにより、ポンピング損失を改善できる火花点火式ガス燃料内燃機関を提供することを課題としている。   The present invention has been made in view of the above-described conventional situation, and provides a spark ignition gas fuel internal combustion engine that can improve pumping loss by reducing the negative pressure of the intake passage in the partial load operation region. It is an issue.

請求項１の発明は、燃焼室に連通する吸気通路と、該吸気通路の燃焼室に開口する吸気開口を開閉する吸気弁と、前記吸気通路に配設され、機関運転状態に応じて通路面積を変化させる吸気制御弁と、前記吸気通路の吸気制御弁より上流側に配設されたスロットル弁と、前記吸気制御弁をバイパスするように、かつ前記燃焼室内において吸気渦流を生成するよう設けられたバイパス通路と、該バイパス通路に介設され、吸気の気筒側への流れのみを許容する逆止弁とを備えた火花点火式ガス燃料内燃機関であって、前記吸気通路の吸気制御弁より下流側にガス燃料を供給するガス燃料供給弁を配設し、少なくとも前記吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、もしくは吸気行程前半に供給することを特徴としている。   According to the first aspect of the present invention, an intake passage that communicates with the combustion chamber, an intake valve that opens and closes an intake opening that opens into the combustion chamber of the intake passage, and a passage area that is disposed in the intake passage and that depends on the engine operating state. An intake control valve for changing the intake passage, a throttle valve disposed upstream of the intake control valve in the intake passage, and an intake vortex in the combustion chamber so as to bypass the intake control valve. A spark ignition type gas fuel internal combustion engine provided with a bypass passage and a check valve that is interposed in the bypass passage and allows only the flow of intake air to the cylinder side, the intake control valve of the intake passage A gas fuel supply valve for supplying gas fuel is disposed downstream, and at least under the operating conditions in which the intake control valve is substantially fully closed, the gas fuel is supplied before the start of the intake stroke or the first half of the intake stroke. Featuring There.

請求項２の発明は、請求項１に記載のものと同様の火花点火式ガス燃料内燃機関であって、前記バイパス通路の逆止弁より下流側にガス燃料を供給するガス燃料供給弁を配設し、少なくとも前記吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、もしくは吸気行程前半に供給することを特徴としている。   The invention of claim 2 is a spark ignition type gas fuel internal combustion engine similar to that of claim 1, wherein a gas fuel supply valve for supplying gas fuel downstream from the check valve of the bypass passage is arranged. The gas fuel is supplied before the start of the intake stroke or in the first half of the intake stroke at least under an operating condition where the intake control valve is substantially fully closed.

ここで、本発明において、ガス燃料を吸気行程開始前に供給するとは、必ずしも必要燃料量の全てを供給する必要はなく、その一部を供給する場合も含む。   Here, in the present invention, supplying gas fuel before the start of the intake stroke does not necessarily require supplying all of the required fuel amount, but also includes supplying a part thereof.

また、本発明において、吸気行程前半とは、吸気行程開始から吸気弁のリフト量が最大リフトとなるまでの期間を意味する。   In the present invention, the first half of the intake stroke means a period from the start of the intake stroke until the lift amount of the intake valve reaches the maximum lift.

請求項３の発明は、請求項１又は２に記載の火花点火式ガス燃料内燃機関において、前記吸気通路の吸気制御弁とスロットル弁との間にはサージタンクが接続され、前記吸気制御弁は、前記吸気通路の前記サージタンクの接続部近傍に設けられていることを特徴としている。   According to a third aspect of the present invention, in the spark ignition gas fuel internal combustion engine according to the first or second aspect, a surge tank is connected between the intake control valve and the throttle valve of the intake passage, and the intake control valve is In the intake passage, it is provided in the vicinity of the connection portion of the surge tank.

請求項４の発明は、請求項１又は２に記載の火花点火式ガス燃料内燃機関において、少なくとも低負荷運転域では、前記吸気行程開始前にガス燃料の供給を終了することを特徴としている。   According to a fourth aspect of the present invention, in the spark ignition type gas fuel internal combustion engine according to the first or second aspect, the supply of the gas fuel is terminated before the intake stroke is started at least in a low load operation region.

請求項１の発明に係る内燃機関によれば、少なくとも吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、あるいは吸気行程前半に吸気通路に供給するようにしている。吸気行程開始前にガス燃料を吸気通路に供給した場合は、極低負荷運転域において有効である。即ち、極低負荷運転域では、吸気制御弁が全閉されている点及びバイパス通路に逆止弁が配設されている点から、吸気通路は負圧状態が維持されている。この負圧状態の吸気通路に、液体燃料に比べて容積の大きいガス燃料を供給することにより、吸気通路の負圧が低減され、ポンピング損失を改善できる。例えば、常温で極めて短時間にガス化するＬＰＧ燃料を供給した場合には、吸気通路の吸気弁上流側の負圧が直ちに低減され、ポンピング損失を改善できる。また吸気行程開始前に燃料ガスを供給することで内部ＥＧＲが低減されることにより、極低負荷運転域での燃焼状態が改善される。   According to the internal combustion engine of the first aspect of the present invention, the gas fuel is supplied to the intake passage before the start of the intake stroke or the first half of the intake stroke at least under an operating condition in which the intake control valve is substantially fully closed. Yes. When gas fuel is supplied to the intake passage before the intake stroke starts, it is effective in the extremely low load operation region. That is, in the extremely low load operation region, the intake passage is maintained in a negative pressure state because the intake control valve is fully closed and the check valve is provided in the bypass passage. By supplying gas fuel having a volume larger than that of liquid fuel to the intake passage in the negative pressure state, the negative pressure in the intake passage is reduced, and the pumping loss can be improved. For example, when LPG fuel that is gasified at room temperature in a very short time is supplied, the negative pressure upstream of the intake valve in the intake passage is immediately reduced, and the pumping loss can be improved. Further, the internal EGR is reduced by supplying the fuel gas before the start of the intake stroke, whereby the combustion state in the extremely low load operation region is improved.

吸気行程前半にガス燃料を吸気通路に供給した場合は、中・高負荷運転域で有効である。即ち、この場合、吸気弁の開き始めには吸気通路に大きな負圧があるため内部ＥＧＲ量を維持でき、さらに吸気行程前半にガス燃料を供給することでトータルの混合気量（新気＋ガス燃料＋内部ＥＧＲ）が増加して吸気通路の負圧が低下し、ポンピング損失が低減する。さらに内部ＥＧＲによる実質的な圧縮圧力の上昇により、燃費低減効果も期待できる。   When gas fuel is supplied to the intake passage in the first half of the intake stroke, it is effective in the medium and high load operation range. That is, in this case, since the intake passage has a large negative pressure at the beginning of opening of the intake valve, the internal EGR amount can be maintained, and further, by supplying gas fuel in the first half of the intake stroke, the total mixture amount (new air + gas Fuel + internal EGR) increases, the negative pressure in the intake passage decreases, and the pumping loss decreases. Furthermore, a fuel consumption reduction effect can be expected due to a substantial increase in compression pressure due to internal EGR.

請求項２の発明によれば、少なくとも吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、もしくは吸気行程前半にバイパス通路に供給するようにしている。吸気行程開始前にガス燃料をバイパス通路に供給した場合は、請求項１の場合と同様に極低負荷運転域において有効であり、吸気通路の負圧状態を低減することができ、ポンピング損失の改善と内部ＥＧＲが低減されることにより、極低負荷運転域での燃焼状態が改善される。   According to the invention of claim 2, the gas fuel is supplied to the bypass passage before the start of the intake stroke or the first half of the intake stroke at least under an operating condition in which the intake control valve is substantially fully closed. When gas fuel is supplied to the bypass passage before the start of the intake stroke, it is effective in the extremely low load operation region as in the case of claim 1, and the negative pressure state of the intake passage can be reduced, and the pumping loss is reduced. By improving and reducing the internal EGR, the combustion state in the extremely low load operation region is improved.

吸気行程前半にガス燃料をバイパス通路に供給した場合は、中・高負荷運転域で有効である。即ち、この場合、請求項１の場合と同様の効果が得られ、さらに吸気行程中にガス燃料をバイパス通路に噴出することで、縦渦，横渦等の強い吸気渦流が形成されることから、急速燃焼が可能となる。また燃焼が遅いとオーバーラップ時に吸気通路内で燃焼するいわゆるバックファイアが生じるが、本発明では前記急速燃焼の効果によりバックファイアを抑制できる。   When gas fuel is supplied to the bypass passage in the first half of the intake stroke, it is effective in the middle and high load operation areas. That is, in this case, the same effect as in the case of claim 1 can be obtained, and further, a strong intake vortex flow such as a vertical vortex and a horizontal vortex is formed by jetting gas fuel into the bypass passage during the intake stroke. Rapid combustion is possible. In addition, when combustion is slow, a so-called backfire is generated that burns in the intake passage at the time of overlap. In the present invention, the backfire can be suppressed by the effect of the rapid combustion.

なお、内部ＥＧＲは、部分負荷運転域においては実質的に圧縮圧力を高める効果があるので、熱効率を向上させるには有効であるものの、理論空燃比（λ＝１）運転では火炎伝播速度が低下し、充分な熱効率効果が得られにくい。本発明では、部分負荷運転域では、バイパス通路からの流れにより、気筒内において横渦又は縦渦の強い吸気渦流が形成されることから、ガス燃料，新気，既燃ガスのミキシングと吸気渦流とにより急速燃焼が可能となり、高効率燃焼，低公害排気ガス，低ポンピング損失が得られる。   The internal EGR has an effect of substantially increasing the compression pressure in the partial load operation region, and is effective in improving the thermal efficiency, but the flame propagation speed is reduced in the theoretical air-fuel ratio (λ = 1) operation. However, it is difficult to obtain a sufficient thermal efficiency effect. In the present invention, in the partial load operation region, the flow from the bypass passage forms an intake vortex having a strong lateral vortex or vertical vortex in the cylinder. Therefore, mixing of gas fuel, fresh air, burned gas, and intake vortex As a result, rapid combustion is possible, and high efficiency combustion, low pollution exhaust gas, and low pumping loss are obtained.

請求項３の発明では、吸気制御弁を、吸気通路のサージタンクの接続部近傍に配置したので、吸気通路の吸気制御弁から吸気弁までの通路容積を大きくすることができ、吸気行程前半において気筒内に吸引するのに必要な空気量を蓄えることができる。その結果、吸気行程前半でのポンピング損失を低減しつつ、吸気行程後半での強い吸気渦流の噴出を実現でき、燃費性能を向上できる。   In the invention of claim 3, since the intake control valve is disposed in the vicinity of the connection portion of the surge tank of the intake passage, the passage volume from the intake control valve to the intake valve of the intake passage can be increased, and in the first half of the intake stroke The amount of air required to be sucked into the cylinder can be stored. As a result, while reducing the pumping loss in the first half of the intake stroke, a strong intake vortex can be ejected in the second half of the intake stroke, and fuel efficiency can be improved.

請求項４の発明では、少なくとも低負荷運転域では、吸気行程開始前にガス燃料の供給を終了するようにしたので、吸気通路の負圧を低減しつつ、内部ＥＧＲの過多を抑制できる。即ち、アイドリング時を含む低負荷運転では、吸入空気量が少ないことから吸気負圧が高くなり、それだけ内部ＥＧＲの流入割合が増加する。このため火炎伝播が不安定となり、失火が生じ易くなる。本発明では、吸気行程開始前にガス燃料の供給を終了するので、それだけガス燃料量が増加し、吸気負圧が低減され、その結果、内部ＥＧＲの流入割合を減少せることができ、安定した燃焼が可能となり、失火を防止できる。   According to the fourth aspect of the present invention, the supply of gas fuel is finished before the start of the intake stroke at least in the low load operation region, so that excessive internal EGR can be suppressed while reducing the negative pressure in the intake passage. That is, in low load operation including idling, the intake air pressure is small because the intake air amount is small, and the inflow rate of the internal EGR is increased accordingly. For this reason, flame propagation becomes unstable and misfire is likely to occur. In the present invention, since the supply of gas fuel is terminated before the start of the intake stroke, the amount of gas fuel is increased accordingly, the intake negative pressure is reduced, and as a result, the inflow rate of the internal EGR can be reduced and stable. Combustion is possible and misfire can be prevented.

以下、本発明の実施の形態を添付図面に基づいて説明する。   Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

図１及び図２は、本発明の第１実施形態による火花点火式ガス燃料内燃機関を説明するための図であり、図１は火花点火式内燃機関の概略構成図、図２は内燃機関の断面図である。   1 and 2 are views for explaining a spark ignition type gas fuel internal combustion engine according to a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram of the spark ignition type internal combustion engine, and FIG. It is sectional drawing.

図において、１は４サイクル多気筒火花点火式ガス燃料内燃機関を示している。該内燃機関１は、複数のシリンダボア（気筒）２ａ，２ａが形成されたシリンダブロック２に、各シリンダボア２ａに対向するよう燃焼凹部３ａが形成されたシリンダヘッド３を接続し、前記各シリンダボア２ａ内にピストン４を摺動自在に挿入配置した概略構造を有する。   In the figure, reference numeral 1 denotes a four-cycle multi-cylinder spark ignition gas fuel internal combustion engine. The internal combustion engine 1 has a cylinder block 2 in which a plurality of cylinder bores (cylinders) 2a, 2a are connected to a cylinder head 3 in which a combustion recess 3a is formed so as to face each cylinder bore 2a. The piston 4 has a schematic structure in which it is slidably inserted.

前記シリンダボア２ａ，燃焼凹部３ａ及びピストン４の頂面で囲まれた空間により燃焼室５が形成されている。また前記ピストン４はコンロッド４ａによりクランク軸１１に連結されている。   A combustion chamber 5 is formed by a space surrounded by the cylinder bore 2 a, the combustion recess 3 a and the top surface of the piston 4. The piston 4 is connected to the crankshaft 11 by a connecting rod 4a.

前記シリンダヘッド３の燃焼凹部３ａには、燃焼室５に連通する２つの吸気開口３ｂ，３ｂと、２つの排気開口３ｃ，３ｃが形成されている。この各吸気開口３ｂ，排気開口３ｃは、それぞれクランク軸の軸線ｃを挟んだ一側，他側に配置され、かつ該軸線ｃを挟んで互いに略対向している。   In the combustion recess 3a of the cylinder head 3, two intake openings 3b and 3b communicating with the combustion chamber 5 and two exhaust openings 3c and 3c are formed. The intake openings 3b and the exhaust openings 3c are disposed on one side and the other side of the crankshaft axis c, and are substantially opposed to each other with the axis c interposed therebetween.

前記各吸気開口３ｂ，排気開口３ｃには、それぞれ吸気弁６，排気弁７が配設され、該吸気弁６，排気弁７はそれぞれ吸気カム軸８，排気カム軸９により開閉駆動される。なお、図示していないが、本実施形態エンジン１は、吸気弁６と排気弁７とが同時に開となるオーバーラップ期間を調整可能とする可変動弁機構を備えている。   The intake opening 3b and the exhaust opening 3c are respectively provided with an intake valve 6 and an exhaust valve 7, and the intake valve 6 and the exhaust valve 7 are opened and closed by an intake cam shaft 8 and an exhaust cam shaft 9, respectively. Although not shown, the engine 1 of this embodiment includes a variable valve mechanism that can adjust an overlap period in which the intake valve 6 and the exhaust valve 7 are simultaneously opened.

前記シリンダヘッド３のシリンダボア２ａには、点火プラグ１０が燃焼凹部３ａの中心に臨むよう装着されている。該点火プラグ１０は、前記軸線ｃより排気弁７側に僅かに偏位して配置されている。   A spark plug 10 is mounted on the cylinder bore 2a of the cylinder head 3 so as to face the center of the combustion recess 3a. The spark plug 10 is disposed slightly displaced from the axis c toward the exhaust valve 7 side.

前記各吸気開口３ｂは、吸気ポート３ｄ，３ｄによりシリンダヘッド３の一側壁に導出され、各排気開口３ｃは、排気ポート３ｅ，３ｅによりシリンダヘッド３の他側壁に導出されている。   Each intake opening 3b is led out to one side wall of the cylinder head 3 by intake ports 3d and 3d, and each exhaust opening 3c is led out to the other side wall of the cylinder head 3 by exhaust ports 3e and 3e.

前記各排気ポート３ｅには、排気管１２が接続され、該排気管１２の合流部１３には触媒１４が接続され、該合流部下流端にはマフラ（不図示）が接続されている。   An exhaust pipe 12 is connected to each exhaust port 3e, a catalyst 14 is connected to the merging portion 13 of the exhaust pipe 12, and a muffler (not shown) is connected to the downstream end of the merging portion.

前記各吸気ポート３ｄには、前記吸気開口３ｂに連通する吸気管（吸気通路）１５，１５が接続されている。   Intake pipes (intake passages) 15 and 15 communicating with the intake opening 3b are connected to the intake ports 3d.

該各吸気管１５の上流端部１５ｂ，１５ｂには、共通のサージタンク１６が接続されており、該サージタンク１６には、吸気合流管１７を介在させてエアクリーナ（不図示）が接続されている。前記吸気合流管１７には各気筒共通のスロットル弁１８が配設されている。   A common surge tank 16 is connected to the upstream end portions 15b, 15b of each intake pipe 15, and an air cleaner (not shown) is connected to the surge tank 16 with an intake merging pipe 17 interposed therebetween. Yes. The intake merging pipe 17 is provided with a throttle valve 18 common to each cylinder.

前記各吸気管１５の上流端部１５ｂには、該内燃機関１の運転状態に応じて通路面積を変化させる吸気制御弁２３，２３が配設されている。該吸気制御弁２３は、吸気管１５のサージタンク１６接続部近傍に配置されている。   At the upstream end portion 15b of each intake pipe 15, intake control valves 23, 23 for changing the passage area according to the operating state of the internal combustion engine 1 are disposed. The intake control valve 23 is disposed in the vicinity of the surge tank 16 connection portion of the intake pipe 15.

前記内燃機関１は、前記吸気制御弁２３をバイパスするよう配設されたバイパス通路２５，２５と、各バイパス通路２５の上流側に設けられた逆止弁２６とを備えている。   The internal combustion engine 1 includes bypass passages 25, 25 arranged to bypass the intake control valve 23, and a check valve 26 provided on the upstream side of each bypass passage 25.

前記各バイパス通路２５は、シリンダボア２ａ内で横渦又は縦渦の吸気流が生成するよう空気を方向付けして噴出させるものであり、前記吸気管１５の下側にこれに沿うように配置されている。   Each bypass passage 25 directs and ejects air so that a horizontal or vertical vortex intake flow is generated in the cylinder bore 2a, and is arranged below the intake pipe 15 along the same. ing.

前記各バイパス通路２５の下流部は、２つの枝管２５ａ，２５ａに分岐され、各枝管２５ａの下流端口２５ａ′はそれぞれ前記吸気ポート３ｄの吸気開口３ｂの近傍に接続されている。即ち、前記バイパス通路２５は前記下流端口２５ａ′を介して前記吸気管１５に連通している。また前記バイパス通路２５の上流端口２５ｂは、前記サージタンク１６に接続されている。   A downstream portion of each bypass passage 25 is branched into two branch pipes 25a and 25a, and a downstream end port 25a 'of each branch pipe 25a is connected to the vicinity of the intake opening 3b of the intake port 3d. That is, the bypass passage 25 communicates with the intake pipe 15 via the downstream end port 25a ′. The upstream end 25 b of the bypass passage 25 is connected to the surge tank 16.

前記逆止弁２６は、吸気の気筒側への流れのみを許容し、逆流を阻止するリード弁型のものであり、前記バイパス通路２５の上流端口２５ｂの近傍に配置されている。   The check valve 26 is of a reed valve type that allows only a flow of intake air to the cylinder side and prevents a reverse flow, and is disposed in the vicinity of the upstream end 25 b of the bypass passage 25.

前記各吸気管１５の吸気制御弁２３より下流側、具体的には吸気ポート３ｄ
の上流端付近には、電磁弁式のガス燃料供給弁２０，２０が装着されている。該各ガス燃料供給弁２０は、水素，プロパン，ブタン等のガス燃料を前記吸気弁６の弁裏中心部に向けて噴射するよう配置されている。 Downstream of the intake control valve 23 of each intake pipe 15, specifically, the intake port 3d.
An electromagnetic valve type gas fuel supply valve 20, 20 is mounted in the vicinity of the upstream end. Each gas fuel supply valve 20 is arranged to inject gas fuel such as hydrogen, propane, butane, etc. toward the center of the back of the intake valve 6.

そして前記内燃機関１は、機関運転状態に応じて、前記吸気制御弁２３を開閉制御するとともに、前記ガス燃料供給弁２０の燃料噴射時期，噴射量を制御するＥＣＵ３２を備えている。   The internal combustion engine 1 includes an ECU 32 that controls the opening and closing of the intake control valve 23 and the fuel injection timing and the injection amount of the gas fuel supply valve 20 according to the engine operating state.

前記ＥＣＵ３２は、低・中負荷の部分負荷運転域では、吸気制御弁２３を全閉とするとともに、ガス燃料を吸気行程の開始前に、吸気管１５の吸気制御弁２３より下流側に噴射供給し、かつ吸気弁６が開く前（吸気行程開始前）にガス燃料の供給を終了するように構成されている。なお、吸気行程前半、つまり吸気弁が開き始めてから最大リフトとなるまでの間にガス燃料を供給するようにしてもよく、また吸気行程の開始前から吸気行程前半に渡ってガス燃料を供給するようにしても良い。   The ECU 32 fully closes the intake control valve 23 and supplies gas fuel to the downstream side of the intake control valve 23 of the intake pipe 15 before the start of the intake stroke in the low and medium load partial load operation regions. In addition, the gas fuel supply is terminated before the intake valve 6 is opened (before the intake stroke starts). Gas fuel may be supplied in the first half of the intake stroke, that is, from when the intake valve starts to open until the maximum lift is reached, or gas fuel is supplied from the start of the intake stroke to the first half of the intake stroke. You may do it.

本実施形態の内燃機関１によれば、吸気制御弁２３を略全閉とする部分負荷運転域では、ガス燃料を吸気管１５に、かつ吸気行程開始前に供給するようにしたので、吸気管１５の負圧状態がガス燃料により低減されることとなり、ポンピング損失を改善できる。即ち、部分負荷運転域においては吸気制御弁２３が略全閉であること、及びバイパス通路２５に逆止弁２６が配設されていることから、吸気管１５内は負圧状態に維持されている。この負圧状態の吸気管１５内に、ガソリン等の液体燃料に比べて容積の大きいガス燃料を供給することにより、吸気管１５の負圧が低減される。例えば、常温で極めて短時間にガス化するＬＰＧ燃料を供給した場合には、吸気管１５の吸気弁６上流側の負圧が直ちに低減され、ポンピング損失をさらに改善できる。   According to the internal combustion engine 1 of the present embodiment, gas fuel is supplied to the intake pipe 15 and before the start of the intake stroke in the partial load operation region where the intake control valve 23 is substantially fully closed. The negative pressure state of 15 is reduced by the gas fuel, and the pumping loss can be improved. That is, in the partial load operation region, the intake control valve 23 is substantially fully closed and the check valve 26 is provided in the bypass passage 25, so that the intake pipe 15 is maintained in a negative pressure state. Yes. By supplying gas fuel having a volume larger than that of liquid fuel such as gasoline into the intake pipe 15 in the negative pressure state, the negative pressure in the intake pipe 15 is reduced. For example, when LPG fuel that is gasified at room temperature in a very short time is supplied, the negative pressure upstream of the intake valve 6 in the intake pipe 15 is immediately reduced, and the pumping loss can be further improved.

本実施形態では、吸気制御弁２３を、吸気管１５のサージタンク１６接続部近傍に配置したので、吸気管１５の吸気制御弁２３から吸気弁６までの通路容積を大きくすることができ、吸気行程前半においてシリンダボア２ａ内に吸引するのに必要な空気量を蓄えることができる。その結果、吸気行程前半でのポンピング損失を低減しつつ、吸気行程後半での強い吸気渦流の噴出を可能にでき、燃費性能を向上できる。   In this embodiment, since the intake control valve 23 is disposed in the vicinity of the surge tank 16 connection portion of the intake pipe 15, the passage volume from the intake control valve 23 to the intake valve 6 of the intake pipe 15 can be increased, and the intake air In the first half of the stroke, the amount of air necessary for suction into the cylinder bore 2a can be stored. As a result, while reducing the pumping loss in the first half of the intake stroke, a strong intake vortex can be ejected in the second half of the intake stroke, and fuel efficiency can be improved.

本実施形態では、ガス燃料供給弁２０を、吸気管１５の吸気制御弁２３より下流側に配置したので、予混合と吸気弁の隙間を通過する際の高速流による乱流とで混合が促進され、シリンダボア２ａ内でのミキシングを良好に行うことができる。   In this embodiment, since the gas fuel supply valve 20 is disposed downstream of the intake control valve 23 of the intake pipe 15, mixing is promoted by premixing and turbulent flow due to high-speed flow when passing through the clearance of the intake valve. Thus, the mixing in the cylinder bore 2a can be performed satisfactorily.

本実施形態では、低負荷運転域では、吸気弁６が開く前にガス燃料の供給を終了するようにしたので、吸気管１５の負圧を低減でき、内部ＥＧＲの過多を抑制できる。即ち、アイドリング時を含む低負荷運転では、吸入空気量が少ないことから吸気負圧が高くなり、それだけ内部ＥＧＲの流入割合が増加する。このため火炎伝播が不安定となり、失火を生じ易くなる。このような現象はオーバーラップ期間が広いほど顕著である。   In the present embodiment, since the supply of gas fuel is terminated before the intake valve 6 is opened in the low load operation region, the negative pressure of the intake pipe 15 can be reduced, and excessive internal EGR can be suppressed. That is, in low load operation including idling, the intake air pressure is small because the intake air amount is small, and the inflow rate of the internal EGR is increased accordingly. For this reason, flame propagation becomes unstable and misfire is likely to occur. Such a phenomenon becomes more prominent as the overlap period is wider.

本実施形態では、吸気弁６が開く前にガス燃料の供給を終了させるので、吸気負圧が低減され、それだけオーバーラップ時の内部ＥＧＲの流入割合を減少させることができ、安定した燃焼が可能となり、失火を防止できる。   In this embodiment, since the supply of gas fuel is terminated before the intake valve 6 is opened, the intake negative pressure is reduced, the inflow rate of the internal EGR at the time of overlap can be reduced, and stable combustion is possible. And misfire can be prevented.

なお、前記実施形態では、部分負荷運転域で、吸気行程開始前にガス燃料を噴射供給するようにしたが、本発明では、吸気行程のオーバーラップ終了後にガス燃料を供給するようにしてもよい。   In the above embodiment, the gas fuel is injected and supplied before the start of the intake stroke in the partial load operation region. However, in the present invention, the gas fuel may be supplied after the overlap of the intake stroke. .

このように、部分負荷運転域で、ガス燃料をオーバーラップ終了後に供給した場合には、排気弁７が閉じた後にガス燃料が供給されることから、排気弁７が閉じる前に導入される内部ＥＧＲを減少させることなく吸気通路の負圧状態を低減することができ、ポンピング損失を改善できる。   As described above, in the partial load operation region, when the gas fuel is supplied after the overlap is completed, the gas fuel is supplied after the exhaust valve 7 is closed, so that the inside introduced before the exhaust valve 7 is closed. The negative pressure state of the intake passage can be reduced without reducing EGR, and the pumping loss can be improved.

またオーバーラップ終了後にガス燃料を供給するので、急速燃焼が可能となり、バックファイヤの抑制も可能となる。   Further, since the gas fuel is supplied after the overlap is completed, rapid combustion is possible and backfire can be suppressed.

前記内燃機関１では、吸気弁６と排気弁７とが同時に開くオーバーラップ期間を設けることにより、適量の内部ＥＧＲを吸気通路に流入させることでポンピング損失を低減して燃費の向上を図ることができる。   In the internal combustion engine 1, by providing an overlap period in which the intake valve 6 and the exhaust valve 7 open simultaneously, an appropriate amount of internal EGR flows into the intake passage, thereby reducing pumping loss and improving fuel efficiency. it can.

本実施形態では、オーバーラップ時にシリンダボア２ａ内から吸気管１５に流入した内部ＥＧＲによって吸気負圧が低減され、さらにオーバーラップ終了後にガス燃料を供給することで内部ＥＧＲを減らすことなく吸気負圧をより減じることができ、ポンピング損失をより改善できる。   In the present embodiment, the intake negative pressure is reduced by the internal EGR flowing into the intake pipe 15 from the cylinder bore 2a during the overlap, and the intake negative pressure is reduced without reducing the internal EGR by supplying gas fuel after the overlap is completed. The pumping loss can be further improved.

また内部ＥＧＲは、部分負荷運転域においては実質的に圧縮圧力を高める効果があるので、熱効率を向上させるには有効であるものの、理論空燃比（λ＝１）運転では火炎伝播速度が低下し、充分な熱効率効果が得られにくい。   The internal EGR has the effect of substantially increasing the compression pressure in the partial load operation region, and is effective in improving the thermal efficiency, but the flame propagation speed is reduced in the theoretical air-fuel ratio (λ = 1) operation. It is difficult to obtain a sufficient thermal efficiency effect.

本実施形態では、部分負荷時には、バイパス通路２５からシリンダボア２ａ内に横渦又は縦渦の強い吸気流が流入することから、ガス燃料，新気，既燃ガスのミキシングとタービュレンスとにより急速燃焼が可能となり、高効率燃焼，低公害排気ガス，低ポンピング損失が得られる。   In this embodiment, at the time of partial load, since the intake flow having a strong horizontal vortex or vertical vortex flows from the bypass passage 25 into the cylinder bore 2a, rapid combustion is performed by mixing and turbulence of gas fuel, fresh air, and burned gas. It is possible to achieve high efficiency combustion, low pollution exhaust gas, and low pumping loss.

図３は、本発明の第２実施形態によるガス燃料内燃機関を説明するための図である。図中、図１と同一符号は同一又は相当部分を示す。   FIG. 3 is a view for explaining a gas fuel internal combustion engine according to a second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

本実施形態のガス燃料内燃機関１は、バイパス通路２５の逆止弁２６より下流側にガス燃料供給弁２０を接続し、吸気行程前半において、具体的には吸気弁６が開き始めてから最大リフトとなるまでの開期間中にガス燃料を供給するように構成されている。   The gas fuel internal combustion engine 1 of the present embodiment connects the gas fuel supply valve 20 downstream of the check valve 26 in the bypass passage 25, and in the first half of the intake stroke, specifically, the maximum lift after the intake valve 6 starts to open. It is configured to supply gas fuel during the open period until it becomes.

本実施形態では、吸気行程前半においてガス燃料をバイパス通路２５に供給するようにしたので、新気とガス燃料によりシリンダボア２ａ内には強い吸気渦流が生成されることとなる（図２の矢印参照）。これにより、良好な燃焼が得られる。その結果、液体燃料に比べて貫通力の小さいガス燃料を供給した場合にも、シリンダボア２ａ内での既燃ガス，新気，ガス燃料のミキシングを促進でき、燃料効率を高めることができる。   In the present embodiment, since gas fuel is supplied to the bypass passage 25 in the first half of the intake stroke, a strong intake vortex flow is generated in the cylinder bore 2a by fresh air and gas fuel (see the arrow in FIG. 2). ). Thereby, good combustion is obtained. As a result, even when gas fuel having a smaller penetration force than liquid fuel is supplied, mixing of burned gas, fresh air, and gas fuel in the cylinder bore 2a can be promoted, and fuel efficiency can be improved.

なお、前記ガス燃料を、吸気行程の開始前にバイパス通路２５に供給するようにしても良い。このようにした場合には、バイパス通路２５を介して吸気通路１５内にガス燃料が充填され、ポンピングロスを低減できる。またオーバーラップ前の吸気負圧を低減できることから、オーバーラップ時の内部ＥＧＲを減量でき、極低負荷運転域での燃焼を改善できる。   The gas fuel may be supplied to the bypass passage 25 before the start of the intake stroke. In this case, the gas fuel is filled into the intake passage 15 via the bypass passage 25, and the pumping loss can be reduced. Moreover, since the intake negative pressure before overlap can be reduced, the internal EGR at the time of overlap can be reduced, and combustion in an extremely low load operation region can be improved.

本発明の第１実施形態による火花点火式ガス燃料内燃機関の概略構成図である。1 is a schematic configuration diagram of a spark ignition type gas fuel internal combustion engine according to a first embodiment of the present invention. 前記内燃機関の断面図である。It is sectional drawing of the said internal combustion engine. 本発明の第２実施形態による火花点火式ガス燃料内燃機関の概略構成図である。It is a schematic block diagram of the spark ignition type gas fuel internal combustion engine by 2nd Embodiment of this invention.

符号の説明Explanation of symbols

１ 内燃機関
３ｂ 吸気開口
５ 燃焼室
６ 吸気弁
７ 排気弁
１２ 排気管（排気通路）
１５ 吸気管（吸気通路）
１６ サージタンク
１８ スロットル弁
２０ ガス燃料供給弁
２３ 吸気制御弁
２５ バイパス通路
２６ 逆止弁 1 Internal combustion engine 3b Intake opening 5 Combustion chamber 6 Intake valve 7 Exhaust valve 12 Exhaust pipe (exhaust passage)
15 Intake pipe (intake passage)
16 Surge tank 18 Throttle valve 20 Gas fuel supply valve 23 Intake control valve 25 Bypass passage 26 Check valve

Claims (4)

燃焼室に連通する吸気通路と、
該吸気通路の燃焼室に開口する吸気開口を開閉する吸気弁と、
前記吸気通路に配設され、機関運転状態に応じて通路面積を変化させる吸気制御弁と、
前記吸気通路の吸気制御弁より上流側に配設されたスロットル弁と、
前記吸気制御弁をバイパスするように、かつ前記燃焼室内において吸気渦流を生成するよう設けられたバイパス通路と、
該バイパス通路に介設され、吸気の気筒側への流れのみを許容する逆止弁と
を備えた火花点火式ガス燃料内燃機関であって、
前記吸気通路の吸気制御弁より下流側にガス燃料を供給するガス燃料供給弁を配設し、
少なくとも前記吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、もしくは吸気行程前半に供給する
ことを特徴とする火花点火式ガス燃料内燃機関。 An intake passage communicating with the combustion chamber;
An intake valve that opens and closes an intake opening that opens into the combustion chamber of the intake passage;
An intake control valve that is disposed in the intake passage and changes a passage area according to an engine operating state;
A throttle valve disposed upstream of the intake control valve in the intake passage;
A bypass passage provided to bypass the intake control valve and to generate an intake vortex in the combustion chamber;
A spark ignition gas fuel internal combustion engine provided with a check valve interposed in the bypass passage and allowing only a flow of intake air to the cylinder side;
A gas fuel supply valve for supplying gas fuel downstream of the intake control valve of the intake passage is disposed;
A spark ignition type gas fuel internal combustion engine which supplies gas fuel before the start of the intake stroke or the first half of the intake stroke at least under an operating condition in which the intake control valve is substantially fully closed. 燃焼室に連通する吸気通路と、
該吸気通路の燃焼室に開口する吸気開口を開閉する吸気弁と、
前記吸気通路に配設され、機関運転状態に応じて通路面積を変化させる吸気制御弁と、
前記吸気通路の吸気制御弁より上流側に配設されたスロットル弁と、
前記吸気制御弁をバイパスするように、かつ前記燃焼室内において吸気渦流を生成するよう設けられたバイパス通路と、
該バイパス通路に介設され、吸気の気筒側への流れのみを許容する逆止弁と
を備えた火花点火式ガス燃料内燃機関であって、
前記バイパス通路の逆止弁より下流側にガス燃料を供給するガス燃料供給弁を配設し、
少なくとも前記吸気制御弁を略全閉とする運転条件下では、ガス燃料を吸気行程開始前に、もしくは吸気行程前半に供給する
ことを特徴とする火花点火式ガス燃料内燃機関。 An intake passage communicating with the combustion chamber;
An intake valve that opens and closes an intake opening that opens into the combustion chamber of the intake passage;
An intake control valve that is disposed in the intake passage and changes a passage area according to an engine operating state;
A throttle valve disposed upstream of the intake control valve in the intake passage;
A bypass passage provided to bypass the intake control valve and to generate an intake vortex in the combustion chamber;
A spark ignition gas fuel internal combustion engine provided with a check valve interposed in the bypass passage and allowing only a flow of intake air to the cylinder side;
A gas fuel supply valve for supplying gas fuel downstream from the check valve of the bypass passage is disposed;
A spark ignition type gas fuel internal combustion engine which supplies gas fuel before the start of the intake stroke or the first half of the intake stroke at least under an operating condition in which the intake control valve is substantially fully closed. 請求項１又は２に記載の火花点火式ガス燃料内燃機関において、
前記吸気通路の吸気制御弁とスロットル弁との間にはサージタンクが接続され、
前記吸気制御弁は、前記吸気通路の前記サージタンクの接続部近傍に設けられている
ことを特徴とする火花点火式ガス燃料内燃機関。 The spark ignition type gas fuel internal combustion engine according to claim 1 or 2,
A surge tank is connected between the intake control valve and the throttle valve in the intake passage,
The spark ignition type gas fuel internal combustion engine, wherein the intake control valve is provided in the vicinity of a connection portion of the surge tank in the intake passage. 請求項１又は２に記載の火花点火式ガス燃料内燃機関において、
少なくとも低負荷運転域では、前記吸気行程開始前にガス燃料の供給を終了する
ことを特徴とする火花点火式ガス燃料内燃機関。 The spark ignition type gas fuel internal combustion engine according to claim 1 or 2,
At least in the low load operation region, the spark fuel gas fuel internal combustion engine is characterized in that the supply of gas fuel is terminated before the intake stroke starts.
JP2008200480A 2008-08-04 2008-08-04 Spark ignition gas fuel internal combustion engine Expired - Fee Related JP5072765B2 (en)

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AT524226B1 (en) * 2021-01-07 2022-04-15 Pges Gmbh Internal combustion engine and method of operating an internal combustion engine

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