WO2024201933A1 - Internal combustion engine with auxiliary combustion chamber - Google Patents

Internal combustion engine with auxiliary combustion chamber Download PDF

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Publication number
WO2024201933A1
WO2024201933A1 PCT/JP2023/013307 JP2023013307W WO2024201933A1 WO 2024201933 A1 WO2024201933 A1 WO 2024201933A1 JP 2023013307 W JP2023013307 W JP 2023013307W WO 2024201933 A1 WO2024201933 A1 WO 2024201933A1
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Prior art keywords
combustion chamber
partition wall
main combustion
communication passage
communication
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PCT/JP2023/013307
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French (fr)
Japanese (ja)
Inventor
敏之 山田
欣也 井上
伸治 林
貴之 城田
大 田中
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三菱自動車工業株式会社
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Priority to PCT/JP2023/013307 priority Critical patent/WO2024201933A1/en
Publication of WO2024201933A1 publication Critical patent/WO2024201933A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M19/00—Details, component parts, or accessories of carburettors, not provided for in, or of interest apart from, the apparatus of groups F02M1/00 - F02M17/00
    • F02M19/12—External control gear, e.g. having dash-pots
    • 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

Definitions

  • the present invention relates to an internal combustion engine having a secondary combustion chamber within a main combustion chamber.
  • injector fuel injection device
  • spark plug that is positioned facing the combustion chamber inside the cylinder.
  • Patent Document 1 discloses an internal combustion engine equipped with a secondary combustion chamber within a combustion chamber (main combustion chamber).
  • a mixture with a relatively high fuel concentration is supplied to the secondary combustion chamber, and the mixture in the secondary combustion chamber is ignited by an ignition plug, causing a flame to be injected (ejected) from the secondary combustion chamber into the main combustion chamber and burn the mixture in the main combustion chamber.
  • This makes it possible to improve the ignition of the mixture in the main combustion chamber and increase the output of the internal combustion engine, or to reduce the fuel concentration in the main combustion chamber and improve fuel efficiency.
  • Patent Document 1 discloses an internal combustion engine that has multiple nozzle holes that inject flames from an auxiliary combustion chamber, and is configured so that the flames are injected radially toward the cylinder wall surface.
  • the present invention was made to solve these problems, and aims to provide an internal combustion engine with a pre-combustion chamber that promotes combustion in the pre-combustion chamber.
  • the internal combustion engine with an auxiliary combustion chamber of the present invention comprises a main combustion chamber formed by a cylinder head, a cylinder block, and a piston, an auxiliary combustion chamber provided in the cylinder head and partitioned from the main combustion chamber by a partition wall, a fuel injection device that supplies fuel to the main combustion chamber, and an ignition device that ignites in the auxiliary combustion chamber, and the partition wall is provided with a communication passage that connects the auxiliary combustion chamber to the main combustion chamber, the communication passage having a first communication passage that is provided at the end of the partition wall on the piston side and communicates in the axial direction of the main combustion chamber, and the auxiliary combustion chamber is formed so that the side opposite the piston extends along an axis that is inclined in a predetermined direction with respect to the axis of the main combustion chamber.
  • the communication passage has a plurality of second communication passages arranged in a line circumferentially around the partition wall, the plurality of second communication passages are arranged at the same position in the axial direction of the main combustion chamber, and the extension lines of the plurality of second communication passages are arranged so as to intersect with the extension line of the first communication passage.
  • the fuel that has passed through the multiple second communication passages and flowed into the auxiliary combustion chamber collides on an extension of the first communication passage, generating a flow that moves along the extension of the first communication passage in the opposite direction to the first communication passage. Therefore, a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber by the fuel that has passed through the first and second communication passages and flowed into the auxiliary combustion chamber.
  • the second communication passage located on the predetermined direction side of the partition wall has a larger path cross-sectional area than the other second communication passages.
  • a large amount of the mixture flows in from the second communication passages that are located on the predetermined direction side among the plurality of second communication passages, and a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber.
  • the fuel injection device is provided on the partition wall of the main combustion chamber in the specified direction, and among the plurality of second communication passages, the second communication passage directly facing the fuel injection position of the fuel injection device has a larger opening area on the main combustion chamber side than the other second communication passages.
  • the fuel injected from the fuel injection device flows more into the second communication passage that faces directly out of the multiple second communication passages. Therefore, the penetrating force of the fuel injection can generate a strong swirling flow of the mixture in the auxiliary combustion chamber.
  • the ignition device is a spark plug
  • the central electrode of the spark plug is disposed on the central axis of the auxiliary combustion chamber
  • the ground electrode of the spark plug is disposed laterally with respect to a plane that passes through the central axis of the auxiliary combustion chamber and extends in the predetermined direction.
  • the internal combustion engine with a pre-combustion chamber of the present invention can generate a swirling flow in the pre-combustion chamber, suppressing uneven distribution of the air-fuel mixture in the pre-combustion chamber and promoting combustion in the pre-combustion chamber. This allows a strong flame to be generated in the pre-combustion chamber and injected into the main combustion chamber, improving combustibility in the main combustion chamber and improving output or fuel efficiency.
  • FIG. 1 is a configuration diagram of an intake and exhaust system of an internal combustion engine according to an embodiment of the present invention
  • FIG. 2 is a top view of a cylinder in the internal combustion engine of the present embodiment.
  • FIG. 4 is a vertical cross-sectional view of the inside of a cylinder showing a fuel injection state.
  • FIG. 4 is a vertical cross-sectional view showing a detailed shape of an upper part of the cylinder.
  • FIG. 4 is a vertical cross-sectional view of an upper part of a cylinder, showing a state of fuel movement within an auxiliary combustion chamber.
  • FIG. 1 is a configuration diagram of an intake and exhaust system of an internal combustion engine 1 (an internal combustion engine with an auxiliary combustion chamber) according to one embodiment of the present invention.
  • the internal combustion engine 1 of this embodiment is a direct injection type gasoline engine having an injector 3 (fuel injection device) that injects gasoline, which is a fuel, into a combustion chamber.
  • an air cleaner 6, an intercooler 7, and a throttle valve 8 are provided upstream of the intake port 2 along the flow of intake air.
  • an upstream side exhaust purification catalyst 12 and a downstream side exhaust purification catalyst 13 are provided along the flow of exhaust gas from the exhaust port 31.
  • the internal combustion engine 1 is also equipped with a turbocharger 15 and an EGR system 16 .
  • the EGR system 16 includes an EGR passage 20 that connects the exhaust passage 11 and the intake passage 5 of the internal combustion engine 1, an EGR valve 21 that changes the flow area of the EGR passage 20, and an EGR cooler 22 that cools the exhaust passing through the EGR passage 20.
  • the EGR passage 20 connects the exhaust passage 11 between the upstream side exhaust purification catalyst 12 and the downstream side exhaust purification catalyst 13, and the intake passage 5 between the air cleaner 6 and the compressor of the turbocharger 15.
  • Fig. 2 is a top view of the inside of a cylinder 30 in the internal combustion engine 1 of this embodiment.
  • Fig. 3 is a vertical cross-sectional view of the inside of the cylinder showing a fuel injection state.
  • the internal combustion engine 1 is provided with two intake ports 2 and two exhaust ports 31 for each cylinder 30. Furthermore, each of the two intake ports 2 is provided with an intake valve 32, and each of the two exhaust ports 31 is provided with an exhaust valve 33.
  • the injector 3 is provided in the cylinder head 34, one for each cylinder, and is disposed circumferentially between the two intake ports 2.
  • the injector 3 is disposed so as to inject fuel toward the combustion chamber, more specifically, toward an upper portion of the center of a main combustion chamber 41, which will be described later.
  • An ignition plug 35 (ignition device) is provided in the center of the cylinder head 34.
  • a main combustion chamber 41 is provided, which is a substantially cylindrical space surrounded by a cylinder block 36, a cylinder head 34, and a piston 37, and a sub-combustion chamber 43 is provided in the upper center of the main combustion chamber 41.
  • a partition wall 42 is provided in the cylinder head 34 so as to surround a center electrode 35a of the ignition plug 35, and the portion surrounded by the partition wall 42 in the main combustion chamber 41 becomes the sub-combustion chamber 43.
  • the main combustion chamber 41 has a substantially circular cross section taken along a plane perpendicular to the moving direction of the piston 37.
  • the partition wall 42 is formed in a cylindrical shape that protrudes downward (toward the piston 37) from the ignition plug 35, and has a substantially hemispherical lower part, and is disposed so as to cover the center electrode 35a and the ground electrode 35b of the ignition plug 35.
  • the center electrode 35a of the ignition plug 35 is located in the upper center of the sub-combustion chamber 43, i.e., in the upper part of the partition wall 42 and on the central axis.
  • the partition wall 42 has multiple communication passages 44a, 44b, 44c that connect the main combustion chamber 41 and the auxiliary combustion chamber 43.
  • the operation of the internal combustion engine 1 is controlled by a control unit 50 (control unit).
  • the control unit 50 is composed of an output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc.
  • the control unit 50 acquires the crank angle, intake volume, exhaust temperature, EGR gas volume, etc., and controls the operation of the injector 3, spark plug 35, throttle valve 8, EGR valve 21, etc.
  • the partition wall 42 and spark plug 35 of this embodiment are positioned near the central axis of the cylinder 30, with their upper portions (the side opposite the piston 37) inclined toward the intake side (the intake valve 32 side: the specified direction in this invention) with respect to the axis CL1 of the cylinder 30 (the central axis of the main combustion chamber 41).
  • the upper portions of the partition wall 42 and the central axis CL2 of the auxiliary combustion chamber 43 therein are inclined toward the intake side with respect to the axis CL1 of the cylinder 30.
  • a plurality of (for example, eight) communication passages 44 a, 44 b are arranged at substantially equal intervals in the circumferential direction of the partition wall 42 .
  • the communication passages 44 a and 44 b are provided at a position slightly below the upper end of the hemispherical portion of the lower part of the partition wall 42 .
  • one communication passage 44a is provided in a position directly facing the injector 3.
  • the fuel injected from the injector 3 is mainly injected toward the communication passage 44a.
  • the communication passages 44a, 44b are arranged on the same plane perpendicular to the axis CL1 of the cylinder 30.
  • the communication passages 44a, 44b extend at an angle to the plane perpendicular to the axis CL1 of the cylinder 30, and are inclined upward (toward the spark plug 35) from the main combustion chamber 41 toward the auxiliary combustion chamber 43.
  • the axes of the communication passages 44a, 44b are set to intersect at the same intersection CP1 on the axis CL2 of the partition wall 42.
  • the partition wall 42 is located near the central axis of the cylinder 30, and the intersection CP1 of the axes of the communication passages 44a and 44b is located on the axis CL1 of the cylinder 30.
  • a communication passage 44c (first communication passage) is provided at the lower end of the partition wall 42. More specifically, the communication passage 44c is provided at a position of the partition wall 42 closest to the piston 37, and extends on the axis CL1 of the cylinder 30. The intersection CP1 of the axes of the communication passages 44a and 44b is located on an extension of the communication passage 44c.
  • the internal combustion engine 1 of this embodiment is provided with an auxiliary combustion chamber 43 partitioned by a partition wall 42 in the upper center of the main combustion chamber 41.
  • the partition wall 42 is provided with communication passages 44a, 44b, and 44c that connect the main combustion chamber 41 and the auxiliary combustion chamber 43.
  • this embodiment uses a direct-injection type injector 3, which first injects fuel to supply it into the main combustion chamber 41. Then, it injects again to supply fuel to the auxiliary combustion chamber 43.
  • the injector 3 is positioned to inject fuel toward the auxiliary combustion chamber 43, and as the piston 37 moves in the compression direction while injecting fuel, some of the fuel that has reached the vicinity of the auxiliary combustion chamber 43 flows into the auxiliary combustion chamber 43 from the communication passages 44a, 44b, and 44c. The remaining fuel that does not flow into the auxiliary combustion chamber 43 is mixed with the intake air in the main combustion chamber 41, just like the fuel that was initially injected.
  • the flame generated by ignition in the auxiliary combustion chamber 43 passes through the connecting passages 44a, 44b, and 44c and is injected into the main combustion chamber 41, combusting the mixture in the main combustion chamber 41.
  • the lower end of the partition wall 42 is provided with a communication passage 44c, which extends parallel to the axis CL1 of the cylinder 30. During the compression stroke when the piston 37 moves upward, fuel flows from the communication passage 44c toward the upper part of the auxiliary combustion chamber 43.
  • the central axis CL2 of the auxiliary combustion chamber 43 is inclined toward the intake side at its upper part with respect to the axis CL1 of the cylinder 30, so that the fuel that flows into the auxiliary combustion chamber 43 from the communication passage 44c moves from the center of the auxiliary combustion chamber 43 toward a position biased toward the exhaust side. Then, when it collides with the ignition plug 35 and turns around, a swirling flow is generated in the auxiliary combustion chamber as shown by the arrows in Figure 5. This promotes the diffusion of fuel in the auxiliary combustion chamber 43, improving the combustibility in the auxiliary combustion chamber 43.
  • a strong flame is generated in the auxiliary combustion chamber 43 and injected into the main combustion chamber 41 from the connecting passages 44a, 44b, and 44c, which increases the combustibility of the mixture in the main combustion chamber 41, improving the output of the internal combustion engine 1 or improving fuel efficiency by reducing the amount of fuel injection. It is also possible to prevent unburned gas from leaking out of the main combustion chamber 41.
  • the partition wall 42 is provided with a plurality of communication passages 44a, 44b arranged in the circumferential direction, so that during the compression stroke, fuel also flows into the auxiliary combustion chamber 43 through the communication passages 44a, 44b.
  • the extension lines of the communicating passages 44a, 44b are inclined upwardly on the opposite side to the communicating passage 44c with respect to a direction perpendicular to the extension line of the communicating passage 44c (the axis CL1 of the cylinder 30) and are arranged so as to intersect on the extension line (CL1) of the communicating passage 44c. Therefore, the fuel flowing in from the communicating passages 44a, 44b collides on the extension line (CL1) of the communicating passage 44c, generating a flow that moves toward the upper part of the auxiliary combustion chamber 43 along the extension line of the communicating passage 44c.
  • a swirling flow of the mixture can be generated in the auxiliary combustion chamber 43 by the fuel that flows from the main combustion chamber 41 through the communication passages 44 a , 44 b , and 44 c into the auxiliary combustion chamber 43 .
  • the communication passage 44a located on the side in the direction in which the upper part of the auxiliary combustion chamber 43 slopes is formed to have a larger path cross-sectional area on the main combustion chamber 41 side than the other communication passages 44b. Therefore, since more fuel flows in from the communication passage 44a out of the multiple communication passages 44a, 44b, a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber 43.
  • the communication passage 44a directly facing the fuel injection port 3a of the injector 3 allows fuel to flow directly into the communication passage 44a by injection from the injector 3.
  • the communication passage 44a directly facing the fuel injection port 3a has a larger opening area on the main combustion chamber 41 side than the other communication passages 44b, so that the penetrating force of the fuel injection strongly flows fuel from the communication passage 44a toward the exhaust side of the auxiliary combustion chamber 43.
  • the partition wall 42 has a plurality of communication passages 44a, 44b arranged at approximately equal intervals in the circumferential direction, so that flames are injected from the auxiliary combustion chamber 43 radially outwardly of the main combustion chamber 41 over the entire circumference. This can promote combustibility in the main combustion chamber 41.
  • the size of the opening area and opening direction on the main combustion chamber 41 side of the communicating passages 44a, 44b can be appropriately set. This enables the flame to propagate evenly within the main combustion chamber 41, thereby improving the combustibility in the main combustion chamber 41.
  • the partition wall 42 has a total of eight communication passages 44a and 44b arranged in the circumferential direction, but the number may be more than eight or may be any other number.
  • one cylinder is provided with two intake valves 32 and two exhaust valves 33, but the present invention can be applied to an internal combustion engine with other numbers, such as one intake valve 32 and one exhaust valve 33.
  • the internal combustion engine of the present invention can be applied to various internal combustion engines for driving automobiles, etc.
  • a direct-injection type injector 3 is used as the fuel injection device that supplies fuel to the main combustion chamber 41, but a type that supplies fuel to the intake port can also be used.
  • fuel flows into the auxiliary combustion chamber 43 as an air-fuel mixture, not as injected fuel.
  • a secondary combustion chamber is used that is inclined toward the intake side, but even if it is inclined in a direction different from the intake and exhaust side, such as toward the exhaust side or a direction perpendicular to the intake and exhaust direction, a swirling flow can be generated in the secondary combustion chamber, and the bias of the mixture in the secondary combustion chamber can be suppressed.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Abstract

This internal combustion engine has: a main combustion chamber 41 which is formed from a cylinder head 34, a cylinder block 36, and a piston 37; an auxiliary combustion chamber 43 which is disposed in the cylinder head 34 and separated from the main combustion chamber 41 by a partition wall 42; and a communication passage 44c which is formed in the partition wall 42 and provides communication between the auxiliary combustion chamber 43 and the main combustion chamber 41. The communication passage 44c has a communication passage 44c which is disposed at a piston-side end part of the partition wall 42 and extends in parallel with a central axis CL1 of the main combustion chamber 43, and the auxiliary combustion chamber 43 is formed so as to extend along an axis CL2 with the upper part thereof inclined with respect to the central axis CL1 of the cylinder block 36.

Description

副燃焼室付内燃機関Internal combustion engine with auxiliary combustion chamber
　本発明は、主燃焼室内に副燃焼室を有する内燃機関に関する。 The present invention relates to an internal combustion engine having a secondary combustion chamber within a main combustion chamber.
　自動車に使用されるガソリンエンジン等の内燃機関の多くは、吸気通路や燃焼室内に燃料を噴射するインジェクタ（燃料噴射装置）と、筒内の燃焼室に臨んで配置される点火プラグを有している。 Many internal combustion engines, such as gasoline engines used in automobiles, have an injector (fuel injection device) that injects fuel into the intake passage or combustion chamber, and a spark plug that is positioned facing the combustion chamber inside the cylinder.
　特許文献１には、燃焼室（主燃焼室）内に、副燃焼室を備えた内燃機関が開示されている。特許文献１に記載された内燃機関では、副燃焼室内に比較的燃料濃度の高い混合気を供給し、点火プラグによって副燃焼室内の混合気に着火することで、副燃焼室から火炎が主燃焼室に噴射（噴出）して主燃焼室内の混合気を燃焼させる構成になっている。これにより、主燃焼室内の混合気の着火性を向上させて内燃機関の出力を向上させることができ、あるいは主燃焼室内の燃料濃度を低くして燃費を向上させることが可能である。 Patent Document 1 discloses an internal combustion engine equipped with a secondary combustion chamber within a combustion chamber (main combustion chamber). In the internal combustion engine described in Patent Document 1, a mixture with a relatively high fuel concentration is supplied to the secondary combustion chamber, and the mixture in the secondary combustion chamber is ignited by an ignition plug, causing a flame to be injected (ejected) from the secondary combustion chamber into the main combustion chamber and burn the mixture in the main combustion chamber. This makes it possible to improve the ignition of the mixture in the main combustion chamber and increase the output of the internal combustion engine, or to reduce the fuel concentration in the main combustion chamber and improve fuel efficiency.
　更に、特許文献１には、副燃焼室から火炎を噴射させる噴孔を複数備え、火炎がシリンダ壁面に向かって放射状に噴射されるように構成されている内燃機関が開示されている。 Furthermore, Patent Document 1 discloses an internal combustion engine that has multiple nozzle holes that inject flames from an auxiliary combustion chamber, and is configured so that the flames are injected radially toward the cylinder wall surface.
特開２０１９－３１９６１号公報JP 2019-31961 A
　ところで、例えばシリンダヘッドに備えたインジェクタより燃料を主燃焼室に直接噴射する直噴式の内燃機関が知られている。そして、このような直噴式の内燃機関においても、特許文献１のような副燃焼室を備えた構成にすることが要求される場合がある。 By the way, there is known a direct injection type internal combustion engine in which fuel is directly injected into the main combustion chamber from an injector mounted on the cylinder head. Even in such a direct injection type internal combustion engine, there are cases where it is required to have a configuration with a secondary combustion chamber as in Patent Document 1.
　そして、副燃焼室を有する内燃機関においては、特許文献１のように副燃焼室からの火炎の噴射形態を調整することで、主燃焼室での燃焼を促進させることが可能であるものの、副燃焼室における燃焼性を高めることも重要である。 In an internal combustion engine with a pre-combustion chamber, it is possible to promote combustion in the main combustion chamber by adjusting the flame injection pattern from the pre-combustion chamber as in Patent Document 1, but it is also important to improve combustibility in the pre-combustion chamber.
　本発明はこのような問題を解決するためになされたもので、副燃焼室における燃焼を促進させる副燃焼室付内燃機関を提供することを目的とする。 The present invention was made to solve these problems, and aims to provide an internal combustion engine with a pre-combustion chamber that promotes combustion in the pre-combustion chamber.
　上記目的を達成するため、本発明の副燃焼室付内燃機関は、シリンダヘッドとシリンダブロックとピストンとによって形成される主燃焼室と、前記シリンダヘッドに設けられ区画壁によって前記主燃焼室と区画される副燃焼室と、前記主燃焼室に燃料を供給する燃料噴射装置と、前記副燃焼室内で点火する点火装置と、を有し、前記区画壁に前記副燃焼室と前記主燃焼室とを連通する連通路が設けられた副燃焼室付内燃機関であって、前記連通路は、前記区画壁の前記ピストン側の端部に設けられ前記主燃焼室の軸線方向に連通する第１連通路を有し、前記副燃焼室は、前記ピストンとは反対側が前記主燃焼室の軸線に対し所定方向に傾斜した軸線に沿って延びるように形成されていることを特徴とする。 In order to achieve the above object, the internal combustion engine with an auxiliary combustion chamber of the present invention comprises a main combustion chamber formed by a cylinder head, a cylinder block, and a piston, an auxiliary combustion chamber provided in the cylinder head and partitioned from the main combustion chamber by a partition wall, a fuel injection device that supplies fuel to the main combustion chamber, and an ignition device that ignites in the auxiliary combustion chamber, and the partition wall is provided with a communication passage that connects the auxiliary combustion chamber to the main combustion chamber, the communication passage having a first communication passage that is provided at the end of the partition wall on the piston side and communicates in the axial direction of the main combustion chamber, and the auxiliary combustion chamber is formed so that the side opposite the piston extends along an axis that is inclined in a predetermined direction with respect to the axis of the main combustion chamber.
　これにより、燃料噴射装置から主燃焼室内に供給された燃料が第１連通路を通過して副燃焼室に流入する際に、主燃焼室の軸線に対して傾斜した副燃焼室内に流入するので、副燃焼室内で燃料を含む混合気の旋回流が発生し易くなる。したがって、副燃焼室内での燃焼性を向上させることができる。 As a result, when the fuel supplied from the fuel injection device into the main combustion chamber passes through the first communication passage and flows into the auxiliary combustion chamber, it flows into the auxiliary combustion chamber which is inclined with respect to the axis of the main combustion chamber, making it easier for a swirling flow of the fuel-containing mixture to occur in the auxiliary combustion chamber. This improves the combustibility in the auxiliary combustion chamber.
　好ましくは、前記連通路は、前記区画壁の周方向に並んで設けられた複数の第２連通路を有し、前記複数の第２連通路は、前記主燃焼室の軸線方向で同一位置に配置され、前記複数の第２連通路の延長線が、前記第１連通路の延長線上で交差するように配置されているとよい。
　これにより、複数の第２連通路を通過して副燃焼室内に流入した燃料が第１連通路の延長線上で衝突し、第１連通路の延長線に沿って第１連通路とは反対側に移動する流れを発生させる。したがって、第１連通路及び第２連通路を通過して副燃焼室内に流入した燃料によって、副燃焼室内で混合気の旋回流を強く発生させることができる。 Preferably, the communication passage has a plurality of second communication passages arranged in a line circumferentially around the partition wall, the plurality of second communication passages are arranged at the same position in the axial direction of the main combustion chamber, and the extension lines of the plurality of second communication passages are arranged so as to intersect with the extension line of the first communication passage.
As a result, the fuel that has passed through the multiple second communication passages and flowed into the auxiliary combustion chamber collides on an extension of the first communication passage, generating a flow that moves along the extension of the first communication passage in the opposite direction to the first communication passage. Therefore, a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber by the fuel that has passed through the first and second communication passages and flowed into the auxiliary combustion chamber.
　好ましくは、前記複数の第２連通路のうち、前記区画壁の前記所定方向側に位置する前記第２連通路は、他の前記第２連通路よりも経路断面積が大きいとよい。
　これにより、複数の第２連通路のうちの所定方向側に位置する第２連通路から多く混合気が流入し、副燃焼室内で混合気の旋回流を強く発生させることができる。 Preferably, of the plurality of second communication passages, the second communication passage located on the predetermined direction side of the partition wall has a larger path cross-sectional area than the other second communication passages.
As a result, a large amount of the mixture flows in from the second communication passages that are located on the predetermined direction side among the plurality of second communication passages, and a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber.
　好ましくは、前記燃料噴射装置は前記主燃焼室の前記区画壁の前記所定方向側に備え、前記複数の第２連通路のうち、前記燃料噴射装置の燃料噴射位置に正対する前記第２連通路は、他の前記第２連通路よりも前記主燃焼室側の開口面積が大きいとよい。 Preferably, the fuel injection device is provided on the partition wall of the main combustion chamber in the specified direction, and among the plurality of second communication passages, the second communication passage directly facing the fuel injection position of the fuel injection device has a larger opening area on the main combustion chamber side than the other second communication passages.
　これにより、燃料噴射装置から噴射した燃料が複数の第２連通路のうちの正対する第２連通路に多く流入する。したがって、燃料噴射の貫徹力によって、副燃焼室内で混合気の旋回流を強く発生させることができる。 As a result, the fuel injected from the fuel injection device flows more into the second communication passage that faces directly out of the multiple second communication passages. Therefore, the penetrating force of the fuel injection can generate a strong swirling flow of the mixture in the auxiliary combustion chamber.
　好ましくは、前記点火装置は点火プラグであって、前記点火プラグの中心電極は、前記副燃焼室の中心軸上に配置され、前記点火プラグの接地電極は、前記副燃焼室の中心軸を通り前記所定方向に延びる平面に対して側方に配置されているとよい。 Preferably, the ignition device is a spark plug, the central electrode of the spark plug is disposed on the central axis of the auxiliary combustion chamber, and the ground electrode of the spark plug is disposed laterally with respect to a plane that passes through the central axis of the auxiliary combustion chamber and extends in the predetermined direction.
　これにより、副燃焼室内で発生した混合気の旋回流が中心電極に到達する前に接地電極によって妨げられることを抑制することができ、副燃焼室内での旋回流を維持させる。したがって、点火プラグにおける点火性を向上させるとともに、副燃焼室内での燃焼を促進させることができる。 This prevents the swirling flow of the mixture generated in the auxiliary combustion chamber from being blocked by the ground electrode before it reaches the center electrode, and maintains the swirling flow in the auxiliary combustion chamber. This improves the ignition performance of the spark plug and promotes combustion in the auxiliary combustion chamber.
　本発明の副燃焼室付内燃機関によれば、副燃焼室内で旋回流を発生させて副燃焼室内での混合気の偏りを抑制し、副燃焼室内で燃焼を促進させることができる。これにより、副燃焼室で強い火炎を発生させて主燃焼室に噴射させ、主燃焼室での燃焼性を高めることができ、出力あるいは燃費の向上を図ることができる。 The internal combustion engine with a pre-combustion chamber of the present invention can generate a swirling flow in the pre-combustion chamber, suppressing uneven distribution of the air-fuel mixture in the pre-combustion chamber and promoting combustion in the pre-combustion chamber. This allows a strong flame to be generated in the pre-combustion chamber and injected into the main combustion chamber, improving combustibility in the main combustion chamber and improving output or fuel efficiency.
本発明の一実施形態の内燃機関の給排気系の構成図である。1 is a configuration diagram of an intake and exhaust system of an internal combustion engine according to an embodiment of the present invention; 本実施形態の内燃機関における気筒の上面図である。FIG. 2 is a top view of a cylinder in the internal combustion engine of the present embodiment. 燃料噴射状態を示す気筒内の縦断面図である。FIG. 4 is a vertical cross-sectional view of the inside of a cylinder showing a fuel injection state. 気筒上部の詳細な形状を示す縦断面図である。FIG. 4 is a vertical cross-sectional view showing a detailed shape of an upper part of the cylinder. 副燃焼室内での燃料の移動状態を示す気筒内上部の縦断面図である。FIG. 4 is a vertical cross-sectional view of an upper part of a cylinder, showing a state of fuel movement within an auxiliary combustion chamber.
　以下、図面に基づき本発明の実施形態について説明する。
　図１は、本発明の一実施形態の内燃機関１（副燃焼室付内燃機関）の給排気系の構成図である。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an intake and exhaust system of an internal combustion engine 1 (an internal combustion engine with an auxiliary combustion chamber) according to one embodiment of the present invention.
　図１に示すように、本実施形態の内燃機関１は、燃焼室内に燃料であるガソリンを噴射するインジェクタ３（燃料噴射装置）を有する直噴式のガソリンエンジンである。
　本実施形態の内燃機関１の吸気通路５には、吸気の流れに沿って、エアクリーナー６、インタークーラー７、スロットルバルブ８が吸気ポート２の上流に備えられている。内燃機関１の排気通路１１には、排気ポート３１から排気の流れに沿って、上流側排気浄化触媒１２及び下流側排気浄化触媒１３が備えられている。 As shown in FIG. 1, the internal combustion engine 1 of this embodiment is a direct injection type gasoline engine having an injector 3 (fuel injection device) that injects gasoline, which is a fuel, into a combustion chamber.
In the intake passage 5 of the internal combustion engine 1 of this embodiment, an air cleaner 6, an intercooler 7, and a throttle valve 8 are provided upstream of the intake port 2 along the flow of intake air. In the exhaust passage 11 of the internal combustion engine 1, an upstream side exhaust purification catalyst 12 and a downstream side exhaust purification catalyst 13 are provided along the flow of exhaust gas from the exhaust port 31.
　また、内燃機関１には、過給機（ターボチャージャ）１５、ＥＧＲシステム１６が備えられている。
　ＥＧＲシステム１６は、内燃機関１の排気通路１１と吸気通路５とを連通するＥＧＲ通路２０と、ＥＧＲ通路２０の流路面積を変更するＥＧＲバルブ２１と、ＥＧＲ通路２０を通過する排気を冷却するＥＧＲクーラー２２を備えている。ＥＧＲ通路２０は、上流側排気浄化触媒１２と下流側排気浄化触媒１３との間の排気通路１１と、エアクリーナー６と過給機１５のコンプレッサとの間の吸気通路５とを連結している。 The internal combustion engine 1 is also equipped with a turbocharger 15 and an EGR system 16 .
The EGR system 16 includes an EGR passage 20 that connects the exhaust passage 11 and the intake passage 5 of the internal combustion engine 1, an EGR valve 21 that changes the flow area of the EGR passage 20, and an EGR cooler 22 that cools the exhaust passing through the EGR passage 20. The EGR passage 20 connects the exhaust passage 11 between the upstream side exhaust purification catalyst 12 and the downstream side exhaust purification catalyst 13, and the intake passage 5 between the air cleaner 6 and the compressor of the turbocharger 15.
　図２は、本形態の内燃機関１における気筒３０内の上面図である。図３は、燃料噴射状態を示す気筒内の縦断面図である。
　図２に示すように、内燃機関１は、１つの気筒３０について吸気ポート２が２個及び排気ポート３１が２個備えられている。また、２個の吸気ポート２に吸気バルブ３２が夫々備えられるとともに、２個の排気ポート３１に排気バルブ３３が夫々備えられている。 Fig. 2 is a top view of the inside of a cylinder 30 in the internal combustion engine 1 of this embodiment. Fig. 3 is a vertical cross-sectional view of the inside of the cylinder showing a fuel injection state.
2, the internal combustion engine 1 is provided with two intake ports 2 and two exhaust ports 31 for each cylinder 30. Furthermore, each of the two intake ports 2 is provided with an intake valve 32, and each of the two exhaust ports 31 is provided with an exhaust valve 33.
　内燃機関１の気筒３０の上部（シリンダヘッド３４）には、その中央部を挟んで一方側に２個の吸気ポート２が並んで配置され、他方側に２個の排気ポート３１が並んで配置されている。
　インジェクタ３は、１つの気筒に１個ずつシリンダヘッド３４に備えられ、２個の吸気ポート２の間の周方向位置に配置されている。インジェクタ３は、燃焼室、詳しくは後述する主燃焼室４１の中心部の上部に向かって燃料を噴射するように配置されている。 In the upper portion (cylinder head 34) of a cylinder 30 of the internal combustion engine 1, two intake ports 2 are arranged side by side on one side with the center portion in between, and two exhaust ports 31 are arranged side by side on the other side.
The injector 3 is provided in the cylinder head 34, one for each cylinder, and is disposed circumferentially between the two intake ports 2. The injector 3 is disposed so as to inject fuel toward the combustion chamber, more specifically, toward an upper portion of the center of a main combustion chamber 41, which will be described later.
　シリンダヘッド３４の中心部には、点火プラグ３５（点火装置）が備えられている。
　気筒３０内には、シリンダブロック３６、シリンダヘッド３４及びピストン３７に囲まれた略円柱状の空間である主燃焼室４１が設けられ、更に主燃焼室４１の上部中心部には副燃焼室４３が設けられている。具体的には、シリンダヘッド３４には、点火プラグ３５の中心電極３５ａを囲むように区画壁４２が備えられており、主燃焼室４１内の区画壁４２に囲まれた部分が副燃焼室４３となる。主燃焼室４１は、ピストン３７の移動方向に対して直交する面による断面が略円形になっている。また、区画壁４２は、点火プラグ３５から下方（ピストン３７側）に突出する円筒状に形成され、下部が略半球状になっており、点火プラグ３５の中心電極３５ａ及び接地電極３５ｂを覆うように配置されている。点火プラグ３５の中心電極３５ａは、副燃焼室４３の上部中心部、即ち区画壁４２内の上部かつ中心軸線上に位置している。 An ignition plug 35 (ignition device) is provided in the center of the cylinder head 34.
In the cylinder 30, a main combustion chamber 41 is provided, which is a substantially cylindrical space surrounded by a cylinder block 36, a cylinder head 34, and a piston 37, and a sub-combustion chamber 43 is provided in the upper center of the main combustion chamber 41. Specifically, a partition wall 42 is provided in the cylinder head 34 so as to surround a center electrode 35a of the ignition plug 35, and the portion surrounded by the partition wall 42 in the main combustion chamber 41 becomes the sub-combustion chamber 43. The main combustion chamber 41 has a substantially circular cross section taken along a plane perpendicular to the moving direction of the piston 37. The partition wall 42 is formed in a cylindrical shape that protrudes downward (toward the piston 37) from the ignition plug 35, and has a substantially hemispherical lower part, and is disposed so as to cover the center electrode 35a and the ground electrode 35b of the ignition plug 35. The center electrode 35a of the ignition plug 35 is located in the upper center of the sub-combustion chamber 43, i.e., in the upper part of the partition wall 42 and on the central axis.
　区画壁４２には、主燃焼室４１と副燃焼室４３とを連通する複数の連通路４４ａ、４４ｂ、４４ｃが設けられている。 The partition wall 42 has multiple communication passages 44a, 44b, 44c that connect the main combustion chamber 41 and the auxiliary combustion chamber 43.
　内燃機関１は、コントロールユニット５０（制御部）によって作動制御される。コントロールユニット５０は、出力装置、記憶装置（ＲＯＭ、ＲＡＭ、不揮発性ＲＡＭ等）、中央演算処理装置（ＣＰＵ）等から構成されている。コントロールユニット５０は、クランク角、吸気量、排気温度、ＥＧＲガス量等を取得し、インジェクタ３、点火プラグ３５、スロットルバルブ８、ＥＧＲバルブ２１等を作動制御する。 The operation of the internal combustion engine 1 is controlled by a control unit 50 (control unit). The control unit 50 is composed of an output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. The control unit 50 acquires the crank angle, intake volume, exhaust temperature, EGR gas volume, etc., and controls the operation of the injector 3, spark plug 35, throttle valve 8, EGR valve 21, etc.
　図２～４に示すように、本実施形態の区画壁４２及び点火プラグ３５は、気筒３０の中心軸付近に配置されるとともに、上部（ピストン３７とは反対側）が気筒３０の軸線ＣＬ1（主燃焼室４１の中心軸）に対して吸気側（吸気バルブ３２側：本発明における所定方向）に傾斜して配置されている。即ち、区画壁４２及びその内部の副燃焼室４３の中心軸ＣＬ2が気筒３０の軸線ＣＬ1に対して上部が吸気側に傾斜している。 As shown in Figures 2 to 4, the partition wall 42 and spark plug 35 of this embodiment are positioned near the central axis of the cylinder 30, with their upper portions (the side opposite the piston 37) inclined toward the intake side (the intake valve 32 side: the specified direction in this invention) with respect to the axis CL1 of the cylinder 30 (the central axis of the main combustion chamber 41). In other words, the upper portions of the partition wall 42 and the central axis CL2 of the auxiliary combustion chamber 43 therein are inclined toward the intake side with respect to the axis CL1 of the cylinder 30.
　また、連通路４４ａ、４４ｂ（第２連通路）が区画壁４２の周方向に略等間隔に並んで複数個（例えば８個）配置されている。
　連通路４４ａ、４４ｂは区画壁４２の下部の半球状の部位の上端部より若干下方位置に備えられている。 Further, a plurality of (for example, eight) communication passages 44 a, 44 b (second communication passages) are arranged at substantially equal intervals in the circumferential direction of the partition wall 42 .
The communication passages 44 a and 44 b are provided at a position slightly below the upper end of the hemispherical portion of the lower part of the partition wall 42 .
　周方向に並ぶ複数の連通路４４ａ、４４ｂのうち、１個の連通路４４ａは、インジェクタ３に正対する位置に備えられている。インジェクタ３から噴射された燃料は、主に連通路４４ａに向かって噴射される。 Of the multiple communication passages 44a, 44b arranged in the circumferential direction, one communication passage 44a is provided in a position directly facing the injector 3. The fuel injected from the injector 3 is mainly injected toward the communication passage 44a.
　連通路４４ａ、４４ｂは、気筒３０の軸線ＣL1に対し直交する同一の面上に配置されている。連通路４４ａ、４４ｂは、気筒３０の軸線ＣL1と直交する面に対して傾斜して延びており、主燃焼室４１から副燃焼室４３に向かって上方側（点火プラグ３５側）に傾斜している。連通路４４ａ、４４ｂの軸線は、区画壁４２の軸線ＣL2上の同一の交点ＣＰ1で交差するように設定されている。なお、本実施形態では、区画壁４２が気筒３０の中心軸付近に位置し、連通路４４ａ及び連通路４４ｂの軸線の交点ＣＰ1が、気筒３０の軸線ＣＬ1上に位置している。 The communication passages 44a, 44b are arranged on the same plane perpendicular to the axis CL1 of the cylinder 30. The communication passages 44a, 44b extend at an angle to the plane perpendicular to the axis CL1 of the cylinder 30, and are inclined upward (toward the spark plug 35) from the main combustion chamber 41 toward the auxiliary combustion chamber 43. The axes of the communication passages 44a, 44b are set to intersect at the same intersection CP1 on the axis CL2 of the partition wall 42. In this embodiment, the partition wall 42 is located near the central axis of the cylinder 30, and the intersection CP1 of the axes of the communication passages 44a and 44b is located on the axis CL1 of the cylinder 30.
　更に、区画壁４２の下端部には、連通路４４ｃ（第１連通路）が備えられている。詳しくは、連通路４４ｃは、区画壁４２のうち最もピストン３７に近い位置に備えられており、気筒３０の軸線ＣＬ1上に延びている。なお、連通路４４ａ及び連通路４４ｂの軸線の交点ＣＰ1は、連通路４４ｃの延長線上に位置している。 Furthermore, a communication passage 44c (first communication passage) is provided at the lower end of the partition wall 42. More specifically, the communication passage 44c is provided at a position of the partition wall 42 closest to the piston 37, and extends on the axis CL1 of the cylinder 30. The intersection CP1 of the axes of the communication passages 44a and 44b is located on an extension of the communication passage 44c.
　以上のように、本実施形態の内燃機関１は、主燃焼室４１の上部中心部に区画壁４２によって区画された副燃焼室４３が備えられている。区画壁４２には、主燃焼室４１と副燃焼室４３とを連通する連通路４４ａ、４４ｂ、４４ｃが設けられている。 As described above, the internal combustion engine 1 of this embodiment is provided with an auxiliary combustion chamber 43 partitioned by a partition wall 42 in the upper center of the main combustion chamber 41. The partition wall 42 is provided with communication passages 44a, 44b, and 44c that connect the main combustion chamber 41 and the auxiliary combustion chamber 43.
　図３に示すように、本実施形態では直噴タイプのインジェクタ３を使用しており、まず、主燃焼室４１内に燃料を供給するための噴射を行う。その後、副燃焼室４３に燃料を供給するために再度噴射を行う。インジェクタ３は、副燃焼室４３に向けて燃料を噴射するように配置されており、燃料を噴射するとともにピストン３７が圧縮方向に移動することで、副燃焼室４３付近に到達している燃料の一部が連通路４４ａ、４４ｂ、４４ｃから副燃焼室４３内に流入する。副燃焼室４３に流入しなかった残りの燃料は、最初に噴射された燃料と同じように吸気とともに主燃焼室４１内で混合する。 As shown in FIG. 3, this embodiment uses a direct-injection type injector 3, which first injects fuel to supply it into the main combustion chamber 41. Then, it injects again to supply fuel to the auxiliary combustion chamber 43. The injector 3 is positioned to inject fuel toward the auxiliary combustion chamber 43, and as the piston 37 moves in the compression direction while injecting fuel, some of the fuel that has reached the vicinity of the auxiliary combustion chamber 43 flows into the auxiliary combustion chamber 43 from the communication passages 44a, 44b, and 44c. The remaining fuel that does not flow into the auxiliary combustion chamber 43 is mixed with the intake air in the main combustion chamber 41, just like the fuel that was initially injected.
　そして、点火プラグ３５によって、副燃焼室４３内の混合気に点火すると、副燃焼室４３内で着火して発生した火炎が連通路４４ａ、４４ｂ、４４ｃを通過して主燃焼室４１に噴射され、主燃焼室４１内の混合気を燃焼させる。 When the mixture in the auxiliary combustion chamber 43 is ignited by the spark plug 35, the flame generated by ignition in the auxiliary combustion chamber 43 passes through the connecting passages 44a, 44b, and 44c and is injected into the main combustion chamber 41, combusting the mixture in the main combustion chamber 41.
　区画壁４２の下端部には連通路４４ｃが備えられており、連通路４４ｃは気筒３０の軸線ＣＬ1と平行に延びているので、ピストン３７が上方へ移動する圧縮行程において燃料は連通路４４ｃから副燃焼室４３の上部に向かって流入する。 The lower end of the partition wall 42 is provided with a communication passage 44c, which extends parallel to the axis CL1 of the cylinder 30. During the compression stroke when the piston 37 moves upward, fuel flows from the communication passage 44c toward the upper part of the auxiliary combustion chamber 43.
　本実施形態では、副燃焼室４３の中心軸ＣＬ2が気筒３０の軸線ＣＬ1に対して上部が吸気側に傾斜しているので、連通路４４ｃから副燃焼室４３に流入した燃料は副燃焼室４３の中心から排気側に偏った位置に向かって移動する。そして、点火プラグ３５に衝突して反転することで、副燃焼室内で図５に示す矢印のように旋回流が発生する。これにより、副燃焼室４３内での燃料の拡散を促し、副燃焼室４３内での燃焼性を向上させることができる。 In this embodiment, the central axis CL2 of the auxiliary combustion chamber 43 is inclined toward the intake side at its upper part with respect to the axis CL1 of the cylinder 30, so that the fuel that flows into the auxiliary combustion chamber 43 from the communication passage 44c moves from the center of the auxiliary combustion chamber 43 toward a position biased toward the exhaust side. Then, when it collides with the ignition plug 35 and turns around, a swirling flow is generated in the auxiliary combustion chamber as shown by the arrows in Figure 5. This promotes the diffusion of fuel in the auxiliary combustion chamber 43, improving the combustibility in the auxiliary combustion chamber 43.
　したがって、副燃焼室４３で強い火炎を発生させて連通路４４ａ、４４ｂ、４４ｃから主燃焼室４１に噴射させ、主燃焼室４１での混合気の燃焼性を高めることができ、内燃機関１の出力の向上、あるいは燃料噴射量を抑えて燃費の向上を図ることができる。また、主燃焼室４１からの未燃ガスの流出を抑えることができる。 Therefore, a strong flame is generated in the auxiliary combustion chamber 43 and injected into the main combustion chamber 41 from the connecting passages 44a, 44b, and 44c, which increases the combustibility of the mixture in the main combustion chamber 41, improving the output of the internal combustion engine 1 or improving fuel efficiency by reducing the amount of fuel injection. It is also possible to prevent unburned gas from leaking out of the main combustion chamber 41.
　また、副燃焼室４３内で旋回流を発生させることで、副燃焼室４３の上部に位置する点火プラグ３５の中心電極３５ａ付近で濃い混合気が溜まることも抑制できるので、自着火を防止することができる。 In addition, by generating a swirling flow within the auxiliary combustion chamber 43, it is possible to prevent a rich mixture from accumulating near the central electrode 35a of the spark plug 35 located at the top of the auxiliary combustion chamber 43, thereby preventing self-ignition.
　また、区画壁４２には、周方向に並ぶ複数の連通路４４ａ、４４ｂが備えられているので、圧縮行程において、連通路４４ａ、４４ｂからも燃料が副燃焼室４３に流入する。
　連通路４４ａ、４４ｂの延長線が、連通路４４ｃの延長線（気筒３０の軸線ＣＬ1）の直交方向に対して連通路４４ｃとは反対側の上方に傾斜するとともに、連通路４４ｃの延長線（ＣＬ1）上で交差するように配置されているので、連通路４４ａ、４４ｂから流入した燃料は、連通路４４ｃの延長線（ＣＬ1）上で衝突し、連通路４４ｃの延長線に沿って副燃焼室４３の上部に向かって移動する流れを発生させる。 Furthermore, the partition wall 42 is provided with a plurality of communication passages 44a, 44b arranged in the circumferential direction, so that during the compression stroke, fuel also flows into the auxiliary combustion chamber 43 through the communication passages 44a, 44b.
The extension lines of the communicating passages 44a, 44b are inclined upwardly on the opposite side to the communicating passage 44c with respect to a direction perpendicular to the extension line of the communicating passage 44c (the axis CL1 of the cylinder 30) and are arranged so as to intersect on the extension line (CL1) of the communicating passage 44c. Therefore, the fuel flowing in from the communicating passages 44a, 44b collides on the extension line (CL1) of the communicating passage 44c, generating a flow that moves toward the upper part of the auxiliary combustion chamber 43 along the extension line of the communicating passage 44c.
　これにより、主燃焼室４１から連通路４４ａ、４４ｂ、４４ｃを通過して副燃焼室４３内に流入した燃料によって、副燃焼室４３内で混合気の旋回流を発生させることができる。
　また、区画壁４２の周方向に並ぶ複数の連通路４４ａ、４４ｂのうち、副燃焼室４３の上部が傾斜する方向側に位置する連通路４４ａが他の連通路４４ｂよりも主燃焼室４１側の経路断面積が大きく形成されている。したがって、複数の連通路４４ａ、４４ｂのうち連通路４４ａから多く燃料が流入するので、副燃焼室４３内で混合気の旋回流を強く発生させることができる。 As a result, a swirling flow of the mixture can be generated in the auxiliary combustion chamber 43 by the fuel that flows from the main combustion chamber 41 through the communication passages 44 a , 44 b , and 44 c into the auxiliary combustion chamber 43 .
Furthermore, among the multiple communication passages 44a, 44b arranged in the circumferential direction of the partition wall 42, the communication passage 44a located on the side in the direction in which the upper part of the auxiliary combustion chamber 43 slopes is formed to have a larger path cross-sectional area on the main combustion chamber 41 side than the other communication passages 44b. Therefore, since more fuel flows in from the communication passage 44a out of the multiple communication passages 44a, 44b, a strong swirling flow of the mixture can be generated in the auxiliary combustion chamber 43.
　区画壁４２の周方向に並ぶ複数の連通路４４ａ、４４ｂのうち、インジェクタ３の燃料噴射口３ａに正対する連通路４４ａには、インジェクタ３からの噴射によって直接燃料が連通路４４ａに流入する。複数の連通路４４ａ、４４ｂのうち、燃料噴射口３ａに正対する連通路４４ａが他の連通路４４ｂよりも主燃焼室４１側の開口面積が大きく形成されている、したがって、燃料噴射の貫徹力によって、連通路４４ａから副燃焼室４３内の排気側方向に向けて燃料が強く流入する。これにより、副燃焼室４３内で燃料が上方に向かう際に更に排気側に偏って燃料が向かうことになり、副燃焼室４３内で混合気の旋回流を更に強く発生させることができる。 Of the multiple communication passages 44a, 44b aligned circumferentially around the partition wall 42, the communication passage 44a directly facing the fuel injection port 3a of the injector 3 allows fuel to flow directly into the communication passage 44a by injection from the injector 3. Of the multiple communication passages 44a, 44b, the communication passage 44a directly facing the fuel injection port 3a has a larger opening area on the main combustion chamber 41 side than the other communication passages 44b, so that the penetrating force of the fuel injection strongly flows fuel from the communication passage 44a toward the exhaust side of the auxiliary combustion chamber 43. As a result, when the fuel flows upward in the auxiliary combustion chamber 43, it flows even more biased toward the exhaust side, and the swirling flow of the mixture can be generated even more strongly in the auxiliary combustion chamber 43.
　また、図４に示すように、点火プラグ３５の接地電極３５ｂを、副燃焼室４３内で吸気側あるいは排気側に位置させるのではなく、吸排気方向に直交した方向である側方側に位置させるようにするとよい。 Also, as shown in FIG. 4, it is advisable to position the ground electrode 35b of the spark plug 35 on the lateral side, which is perpendicular to the intake and exhaust directions, rather than on the intake or exhaust side within the auxiliary combustion chamber 43.
　副燃焼室４３内で、旋回流の多くは吸排気方向で旋回するので、接地電極３５ｂを吸排気方向側に対して側方側に位置させることで、接地電極３５ｂが旋回流の妨げになることを抑制することができる。これにより、副燃焼室４３内での旋回流を維持させて、点火プラグ３５における点火性を向上させるとともに、点火後の副燃焼室４３内での燃焼を促進させることができる。
　本実施形態の区画壁４２には、周方向に略等間隔に並んで複数の連通路４４ａ、４４ｂが配置されているので、副燃焼室４３から主燃焼室４１の径方向外方に向かって、全周に亘って火炎が噴射される。これにより、主燃焼室４１での燃焼性を促進させることができる。 Since most of the swirling flow swirls in the intake/exhaust direction in the auxiliary combustion chamber 43, by positioning the ground electrode 35b to the side of the intake/exhaust direction, it is possible to prevent the ground electrode 35b from interfering with the swirling flow. This maintains the swirling flow in the auxiliary combustion chamber 43, improves the ignition performance of the spark plug 35, and promotes combustion in the auxiliary combustion chamber 43 after ignition.
In the present embodiment, the partition wall 42 has a plurality of communication passages 44a, 44b arranged at approximately equal intervals in the circumferential direction, so that flames are injected from the auxiliary combustion chamber 43 radially outwardly of the main combustion chamber 41 over the entire circumference. This can promote combustibility in the main combustion chamber 41.
　なお、例えば副燃焼室４３内での旋回流、主燃焼室４１内で吸気により発生するタンブル流や、主燃焼室４１内の形状等の影響により、主燃焼室４１内で火炎が均等に伝搬しない場合には、連通路４４ａ、４４ｂの主燃焼室４１側の開口面積や開口方向等の大きさを適宜設定すればよい。
　これにより、主燃焼室４１内で火炎を均等に伝搬させることが可能になり、主燃焼室４１での燃焼性を向上させることができる。 In addition, in cases where the flame does not propagate evenly within the main combustion chamber 41 due to, for example, the influence of the swirling flow within the auxiliary combustion chamber 43, the tumble flow generated by the intake air within the main combustion chamber 41, or the shape of the main combustion chamber 41, the size of the opening area and opening direction on the main combustion chamber 41 side of the communicating passages 44a, 44b can be appropriately set.
This enables the flame to propagate evenly within the main combustion chamber 41, thereby improving the combustibility in the main combustion chamber 41.
　本発明は、上記の実施形態に限定するものではない。
　例えば、上記実施形態では、区画壁４２に設けられる連通路４４ａ及び連通路４４ｂが周方向に並んで合計８個備えられているが、８個以上あるいは他の個数であってもよい。 The present invention is not limited to the above-described embodiments.
For example, in the above embodiment, the partition wall 42 has a total of eight communication passages 44a and 44b arranged in the circumferential direction, but the number may be more than eight or may be any other number.
　また、各連通路４４ａ、４４ｂ、４４ｃの位置や詳細な形状については適宜変更してもよい。
　本実施形態では、１つの気筒に吸気バルブ３２が２個、排気バルブ３３が２個備えられているが、例えば吸気バルブ３２が１個、排気バルブ３３が１個といったような他の個数の内燃機関であっても本発明を適用できる。本発明の内燃機関は、自動車の走行駆動用等の各種内燃機関に適用することができる。 Furthermore, the positions and detailed shapes of the communication passages 44a, 44b, and 44c may be changed as appropriate.
In this embodiment, one cylinder is provided with two intake valves 32 and two exhaust valves 33, but the present invention can be applied to an internal combustion engine with other numbers, such as one intake valve 32 and one exhaust valve 33. The internal combustion engine of the present invention can be applied to various internal combustion engines for driving automobiles, etc.
　本実施形態では、主燃焼室４１に燃料を供給する燃料噴射装置として直噴タイプのインジェクタ３を用いたが、吸気ポートに燃料を供給するタイプでも適用することができる。この場合、副燃焼室４３には、噴射された燃料でなく混合気として流入することになる。 In this embodiment, a direct-injection type injector 3 is used as the fuel injection device that supplies fuel to the main combustion chamber 41, but a type that supplies fuel to the intake port can also be used. In this case, fuel flows into the auxiliary combustion chamber 43 as an air-fuel mixture, not as injected fuel.
　さらに、本実施形態では、吸気側に傾斜した副燃焼室を用いたが、排気側や吸排気方向と直交する方向など吸排気側と異なる方向に傾斜しても副燃焼室内で旋回流を発生させて副燃焼室内での混合気の偏りを抑制できる。 In addition, in this embodiment, a secondary combustion chamber is used that is inclined toward the intake side, but even if it is inclined in a direction different from the intake and exhaust side, such as toward the exhaust side or a direction perpendicular to the intake and exhaust direction, a swirling flow can be generated in the secondary combustion chamber, and the bias of the mixture in the secondary combustion chamber can be suppressed.
１　内燃機関（副燃焼室付内燃機関）
３　インジェクタ（燃料噴射装置）
３２　吸気バルブ
３３　排気バルブ
３４　シリンダヘッド
３５　点火プラグ（点火装置）
３６　シリンダブロック
３７　ピストン
４１　主燃焼室
４３　副燃焼室
４２　区画壁
４４ａ　連通路（第２連通路）
４４ｂ　連通路（第２連通路）
４４ｃ　連通路（第１連通路）

  1. Internal combustion engine (internal combustion engine with auxiliary combustion chamber)
3. Injector (fuel injection device)
32 Intake valve 33 Exhaust valve 34 Cylinder head 35 Spark plug (ignition device)
36 Cylinder block 37 Piston 41 Main combustion chamber 43 Auxiliary combustion chamber 42 Partition wall 44a Communication passage (second communication passage)
44b Communication path (second communication path)
44c Communication path (first communication path)

Claims (5)

  1. 　シリンダヘッドとシリンダブロックとピストンとによって形成される主燃焼室と、前記シリンダヘッドに設けられ区画壁によって前記主燃焼室と区画される副燃焼室と、前記主燃焼室に燃料を供給する燃料噴射装置と、前記副燃焼室内で点火する点火装置と、を有し、前記区画壁に前記副燃焼室と前記主燃焼室とを連通する連通路が設けられた副燃焼室付内燃機関であって、
    　前記連通路は、前記区画壁の前記ピストン側の端部に設けられ前記主燃焼室の軸線方向に連通する第１連通路を有し、
    　前記副燃焼室は、前記ピストンとは反対側が前記主燃焼室の軸線に対し所定方向に傾斜した軸線に沿って延びるように形成されている
    ことを特徴とする副燃焼室付内燃機関。     An internal combustion engine with a secondary combustion chamber, comprising: a main combustion chamber formed by a cylinder head, a cylinder block, and a piston; a secondary combustion chamber provided in the cylinder head and partitioned from the main combustion chamber by a partition wall; a fuel injection device for supplying fuel to the main combustion chamber; and an ignition device for igniting fuel in the secondary combustion chamber, wherein a communication passage is provided in the partition wall for communicating the secondary combustion chamber with the main combustion chamber,
    the communication passage includes a first communication passage that is provided at an end of the partition wall on the piston side and communicates with the main combustion chamber in the axial direction,
    1. An internal combustion engine with a pre-combustion chamber, wherein the pre-combustion chamber is formed so that the side opposite to the piston extends along an axis that is inclined in a predetermined direction with respect to the axis of the main combustion chamber.
  2. 　前記連通路は、前記区画壁の周方向に並んで設けられた複数の第２連通路を有し、
    　前記複数の第２連通路は、前記主燃焼室の軸線方向で同一位置に配置され、
    　前記複数の第２連通路の延長線が、前記第１連通路の延長線上で交差するように配置されている
    ことを特徴とする請求項１に記載の副燃焼室付内燃機関。     the communication passage includes a plurality of second communication passages arranged side by side in a circumferential direction of the partition wall,
    The plurality of second communication passages are arranged at the same position in the axial direction of the main combustion chamber,
    2. The internal combustion engine with a pre-combustion chamber according to claim 1, wherein the second communication passages are arranged so that their extension lines intersect with an extension line of the first communication passage.
  3. 　前記複数の第２連通路のうち、前記区画壁の前記所定方向側に位置する前記第２連通路は、他の前記第２連通路よりも経路断面積が大きい
    ことを特徴とする請求項２に記載の副燃焼室付内燃機関。     3. The internal combustion engine with an auxiliary combustion chamber according to claim 2, wherein, of the plurality of second communication passages, the second communication passage located on the side of the partition wall in the predetermined direction has a larger path cross-sectional area than the other second communication passages.
  4. 　前記燃料噴射装置は前記主燃焼室の前記区画壁の前記所定方向側に備え、前記複数の第２連通路のうち、前記燃料噴射装置の燃料噴射位置に正対する前記第２連通路は、他の前記第２連通路よりも前記主燃焼室側の開口面積が大きい
    ことを特徴とする請求項２または３に記載の副燃焼室付内燃機関。     4. The internal combustion engine with an auxiliary combustion chamber according to claim 2 or 3, characterized in that the fuel injection device is provided on the predetermined direction side of the partition wall of the main combustion chamber, and among the plurality of second communication passages, the second communication passage directly facing the fuel injection position of the fuel injection device has a larger opening area on the main combustion chamber side than the other second communication passages.
  5. 　前記点火装置は点火プラグであって、
    　前記点火プラグの中心電極は、前記副燃焼室の中心軸上に配置され、
    前記点火プラグの接地電極は、前記副燃焼室の中心軸を通り前記所定方向に延びる平面に対して側方に配置されている
    ことを特徴とする請求項１から４のいずれか１項に記載の副燃焼室付内燃機関。

          The ignition device is a spark plug,
    The central electrode of the ignition plug is disposed on the central axis of the auxiliary combustion chamber,
    5. The internal combustion engine with a pre-combustion chamber according to claim 1, wherein the ground electrode of the ignition plug is disposed laterally with respect to a plane that passes through a central axis of the pre-combustion chamber and extends in the predetermined direction.
PCT/JP2023/013307 2023-03-30 2023-03-30 Internal combustion engine with auxiliary combustion chamber WO2024201933A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5399110A (en) * 1977-02-08 1978-08-30 Daihatsu Motor Co Ltd Internal combustion engine having precombustion chamber
JPH06307247A (en) * 1993-04-26 1994-11-01 Mitsubishi Heavy Ind Ltd Combustion chamber of auxiliary chamber type internal combustion engine
JP2009270540A (en) * 2008-05-09 2009-11-19 Osaka Gas Co Ltd Engine and ignition plug for engine
WO2020196685A1 (en) * 2019-03-27 2020-10-01 三菱自動車工業株式会社 Sub-chamber internal combustion engine
WO2021157322A1 (en) * 2020-02-05 2021-08-12 株式会社デンソー Subsidiary chamber type ignition system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5399110A (en) * 1977-02-08 1978-08-30 Daihatsu Motor Co Ltd Internal combustion engine having precombustion chamber
JPH06307247A (en) * 1993-04-26 1994-11-01 Mitsubishi Heavy Ind Ltd Combustion chamber of auxiliary chamber type internal combustion engine
JP2009270540A (en) * 2008-05-09 2009-11-19 Osaka Gas Co Ltd Engine and ignition plug for engine
WO2020196685A1 (en) * 2019-03-27 2020-10-01 三菱自動車工業株式会社 Sub-chamber internal combustion engine
WO2021157322A1 (en) * 2020-02-05 2021-08-12 株式会社デンソー Subsidiary chamber type ignition system

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