WO2020196684A1

WO2020196684A1 - Auxiliary chamber-type internal combustion engine

Info

Publication number: WO2020196684A1
Application number: PCT/JP2020/013491
Authority: WO
Inventors: 捷飯塚; 田中　大; 貴之城田; 欣也井上; 佳博菅田; 一成野中; 晃弘津田; 遼太朝倉
Original assignee: 三菱自動車工業株式会社
Priority date: 2019-03-27
Filing date: 2020-03-25
Publication date: 2020-10-01
Also published as: JP2022078373A

Abstract

In this auxiliary chamber-type internal combustion engine, by moving a closing wall relative to a partition wall of an auxiliary chamber in response to progress of the intake, compression, expansion and exhaust strokes, the opening area of a communication passage is changed, and the opening area of the communication passage in the exhaust stroke and the intake stroke is widened to be greater than the opening area of the communication passage in the compression stroke and the expansion stroke. The partition wall has two communication passages of different cross-sectional areas. The closing wall carries out the relative movement, closing the one communication passage while exposing the other communication passage. In this way, the communication passage opening area changes.

Description

Sub-chamber internal combustion engine

The present disclosure relates to a sub-chamber type internal combustion engine having a main chamber and a sub-chamber provided adjacent to the main chamber.

Conventionally, a sub-chamber type internal combustion engine having a main chamber (main combustion chamber) and a sub-chamber (sub-combustion chamber) provided adjacent to the main chamber has been proposed (for example, Japanese Patent Application Laid-Open No. 2004-204835). See Gazette). In such a sub-chamber internal combustion engine, an air-fuel mixture is formed from the fuel injected into the main chamber. The formed air-fuel mixture is supplied to the sub-chamber via the communication passage, and is ignited by the spark plug in the sub-chamber. As a result, a flame is formed. The flame formed in the sub-chamber is jetted into the main chamber through the continuous passage and ignites the air-fuel mixture in the main chamber. Injecting the flame formed in the sub chamber into the main chamber in this way increases the combustion speed of the main chamber, enables operation at a leaner air-fuel ratio, and improves fuel efficiency.

Further, the sub-chamber type internal combustion engine of Japanese Patent Application Laid-Open No. 2004-204835 has a separate scavenging passage that connects the sub-chamber and the intake port, thereby promoting scavenging in the sub-fuel chamber.

However, the scavenging passage of the auxiliary chamber type internal combustion engine of Japanese Patent Application Laid-Open No. 2004-204835 is provided at a position communicating with the auxiliary chamber only when the intake valve is open at the intake port. Moreover, in order to promote scavenging by the scavenging passage, the communication passage is provided away from the scavenging passage (offset to the opposite side of the scavenging passage), and the position of the communication passage is greatly restricted regardless of the function as the scavenging passage. Will be done.

The embodiment of the present disclosure relates to a sub-chamber internal combustion engine that promotes scavenging without significantly restricting the position of the communication passage.

According to an embodiment of the present disclosure, the sub-chamber internal combustion engine is a sub-chamber internal combustion engine that repeats intake, compression, expansion, and exhaust strokes, and is a main chamber, a sub chamber, a communication passage, and a blockage. It includes a wall and a displacement mechanism. The main chamber is defined by a cylinder head, a cylinder, and a piston. The sub chamber projects from the cylinder head toward the main chamber and is separated from the main chamber by a partition wall. The communication passage penetrates the partition wall and connects the main room and the sub room. The closing wall is provided in the main chamber and outside the sub chamber, and partially closes the opening of the connecting passage. The displacement mechanism changes the relative position between the partition wall and the closed wall between the first position where a part of the opening of the communication passage is closed and the second position where the opening area of the communication passage is larger than the first position. Let me. The displacement mechanism changes the relative position of the bulkhead and the closing wall to the first position in the compression stroke and the expansion stroke, while changing the relative position of the bulkhead and the closing wall to the second position in the exhaust stroke and the intake stroke. Let me.

This sub-chamber internal combustion engine changes the opening area of the communication passage by changing the relative positions of the partition wall and the closed wall according to each stroke of intake, compression, expansion, and exhaust. Then, the opening area of the communication passage in the exhaust stroke and the intake stroke is expanded more than the opening area of the communication passage in the compression stroke and the expansion stroke. In this way, scavenging of the sub-chamber is promoted in the exhaust stroke and the intake stroke.

In this configuration, it is sufficient that a part of the communication passage is blocked by the blocking wall, and the restriction on the position of the communication passage is removed.

The continuous passage may have a first continuous passage and a second continuous passage whose cross section is larger than the cross section of the first continuous passage. The blocking wall may block only the second passage at the first position, while blocking only the first passage at the second position.

In this sub-chamber internal combustion engine, the opening area of the communication passage is changed by closing the other communication passage while exposing one communication passage.

The first passage and the second passage may be arranged adjacent to each other in the protruding direction of the sub chamber, and may be arranged in the order of the first passage and the second passage from the cylinder head. The gangway wall may have a gangway having a cross section equal to or larger than the cross section of the second passage, and a gangway extending from both sides of the gangway along the projecting direction of the sub chamber. Then, when the relative position is the first position, the displacement mechanism exposes the first passage by overlapping the gangway with the first passage while blocking the second passage by overlapping the closing portion with the second passage. When the relative position is the second position, the closed portion may overlap the first passage to block the first passage, and the gangway may overlap the second passage to expose the second passage. ..

In this sub-chamber internal combustion engine, one of the passages is exposed by changing the relative positions of the partition wall and the closure wall so that the gangway and the closing portion overlap with either the first passage or the second passage, respectively. While letting it block the other passage.

In this sub-chamber internal combustion engine, as long as the relative positions of the partition wall and the closing wall can be changed, the closing wall may move or the partition wall may move.

The displacement mechanism moves the partition wall in the protrusion direction of the sub chamber so that the relative position is the first position when the protrusion amount of the partition wall is the maximum and the relative position is the second position when the protrusion amount of the partition wall is the minimum. You may move it.

In this sub-chamber internal combustion engine, the relative position of the bulkhead and the closed wall changes by moving the bulkhead.

The displacement mechanism rotates as the intake, compression, expansion and exhaust strokes progress, and in the exhaust and intake strokes, it rotates to the first rotation position where the lift amount is either maximum or minimum, and also From the displacement cam that rotates to the second rotation position where the lift amount is either the maximum or the minimum in each stroke of compression and expansion, and the maximum lift amount along the protruding direction of the auxiliary chamber following the displacement cam. It may have a follower that reciprocates the distance to the minimum lift amount. Then, the subordinate may directly or indirectly transmit the reciprocating motion to the obstruction wall or the partition wall to change the relative positions of the two.

In this sub-chamber internal combustion engine, cams and followers change the relative position of the bulkhead and the closed wall.

Schematic diagram showing a schematic configuration of a sub-chamber internal combustion engine according to an embodiment of the present disclosure. Cross-sectional view of the main part near the auxiliary chamber in FIG. Cross-sectional view of the main part near the auxiliary chamber in FIG. Schematic diagram showing the relationship between each stroke of the sub-chamber internal combustion engine of FIG. 1 and the position of the partition wall. Sectional sectional view of the main part in the vicinity of the sub chamber in another embodiment of the present disclosure. Sectional sectional view of the main part in the vicinity of the sub chamber in another embodiment of the present disclosure.

(1) Overall Configuration As shown in FIG. 1, the sub-chamber internal combustion engine 1 has a main chamber 10 having a structure surrounding a combustion space 100 extending in a tubular shape, and a sub-chamber extending in a tubular shape toward the combustion space 100. 20, an ignition plug 30 protruding from the inner wall of the sub chamber 20, and a closing wall 40 surrounding the sub chamber 20 are provided, and are configured to repeat each stroke of intake, compression, expansion, and exhaust. ..

The main chamber 10 reciprocates along a cylinder 11 extending in a predetermined direction (vertical direction in the figure), a cylinder head 13 closing one end (upper end in the figure) side of the cylinder 11, and the inside of the cylinder 11 along the extending direction. It has a moving piston 15, and the combustion space 100 of the main chamber 10 is defined by a cylinder 11, a cylinder head 13, and a piston 15. The combustion space 100 is connected to an intake port 120 opened and closed by an intake valve 110 and an exhaust port 140 opened and closed by an exhaust valve 130. The intake valve 110 and the exhaust valve 130 are driven by the intake cam 210 and the exhaust cam 220, which will be described later.

Further, the main chamber 10 has an injection valve 150 for injecting fuel into the combustion space 100 in the vicinity of the intake port 120 in the cylinder 11. The injection valve 150 forms an air-fuel mixture in the combustion space 100 by spraying and supplying fuel.

The main chamber 10 in the present embodiment has a pent roof shape, and the cylinder head 13 has two inclined surfaces extending toward the intake port 120 and the exhaust port 140, respectively.

The sub chamber 20 is separated from the main chamber 10 by a partition wall 21. As shown in FIGS. 2A and 2B, the partition wall 21 projects from the cylinder head 13 toward the combustion space 100 of the main chamber 10 and extends in a cylindrical shape having a circular cross section. In the present embodiment, the sub chamber 20 is provided at a position straddling the intersection line (ridge line) of the two slopes of the pent roof-shaped main chamber 10.

The communication passage penetrates the partition wall 21 of the sub chamber 20 inside and outside to communicate the sub chamber 20 and the main room 10. This communication passage has a first communication passage 23 having a predetermined first area having a cross-sectional area (specifically, an area in a cross section intersecting the communication direction) communicating with the partition wall 21 and a first cross section. It has a second passage 25 having a second area larger than the area. These are adjacent to each other in the order of the first passage 23 and the second passage 25 from the cylinder head 13 toward the combustion space 100 of the main chamber 10 along the projecting direction of the sub chamber 20 (vertical direction in FIG. 2). Have been placed.

The spark plug 30 has an electrode pair, and the electrode pair protrudes from the inner wall on the end side (upper end in FIGS. 2A and 2B) of the sub chamber 20. The spark plug 30 ignites the air-fuel mixture in the sub chamber 20 by energizing between the

electrodes

31 and 33 forming the electrode pair. In the present embodiment, the

electrodes

31 and 33 overlap the axis of the cylinder in the sub chamber 20, but may be separated from this axis.

The closing wall 40 is provided in the main room and outside the sub room. The closing wall 40 surrounds the sub chamber 20 and is movable relative to the partition wall 21 in the projecting direction of the sub chamber 20.

Further, the closing wall 40 is a closing that extends from both sides of the gangway 41 having a cross section of the second area or more (the same as the second area in the present embodiment) and the gangway 41 along the projecting direction of the sub chamber 20. It has a part 43 and. Then, in the closing wall 40, one of the closing portions 43 overlaps the first passage 23 to block the first passage 23, and the gangway 41 overlaps the second passage 25 to expose the second passage 25. The gangway 41 overlaps with the first passage 23 while blocking the second passage 25 with the buried position (see FIG. 2A) and the other closing portion 43 overlaps with the second passage 25 to form the first passage 23. It moves relative to the protruding position to be exposed (see FIG. 2B).

The relative movement of the closed wall 40 with respect to the partition wall 21 is realized by the displacement mechanism 50. That is, the displacement mechanism 50 changes the relative positions of the partition wall 21 and the closing wall 40.

The displacement mechanism 50 moves the closing wall 40 relative to the partition wall 21 so that the closing wall 40 closes a part of the communication passage. The displacement mechanism 50 is driven by a displacement cam 51 that rotates according to the progress of the stroke (intake, compression, expansion, and exhaust) of the sub-chamber internal combustion engine 1 and the displacement cam 51 along the protruding direction of the sub-chamber 20. It is provided with a follower 53 that reciprocates the distance from the maximum lift amount to the minimum lift amount, and a transmission unit 55 that directly or indirectly transmits the reciprocating motion of the follower 53 to the closed wall 40 or the partition wall 21. ing.

The displacement cam 51 rotates together with the intake cam 210 and the exhaust cam 220 based on the rotation of the crankshaft (not shown) transmitted via the timing belt 230, and the rotation that minimizes the lift amount in the exhaust and intake strokes. It is placed in position (see FIG. 2A) and in the rotational position where the lift amount is maximized during the compression and expansion strokes (see FIG. 2B).

The displacement mechanism 50 relatively moves the closing wall 40 to the first position where the opening area of the communication passage is the first area in the compression stroke and the expansion stroke by the above-mentioned components, while in the exhaust stroke and the intake stroke. The closed wall 40 is relatively moved to a second position where the opening area of the communication passage is the second area.

Specifically, in the exhaust stroke and the intake stroke, as shown in FIG. 2A, the through-passage 41 of the block wall 40 overlaps with the second passage 25 of the partition wall 21 due to the relative movement of the block wall 40, and the block wall 40 When one of the closing portions 43 overlaps with the first connecting passage 23 of the partition wall 21, the opening area of the connecting passage becomes the second area. Further, in the compression stroke and the expansion stroke, as shown in FIG. 2B, due to the relative movement of the closing wall 40, the through-passage 41 of the closing wall 40 overlaps with the first continuous passage 23 of the partition wall 21, and the other closing of the closing wall 40 is closed. By overlapping the portion 43 with the second connecting passage 25 of the partition wall 21, the opening area of the connecting passage becomes the first area.

In the sub-chamber internal combustion engine 1 configured in this way, the volume of the sub-chamber 20 is smaller than that of the main chamber 10, and the flame of the air-fuel mixture ignited by the spark plug 30 quickly propagates into the sub-chamber 20. The sub chamber 20 injects the flame generated in the sub chamber 20 into the main chamber 10 via the continuous passage. The flame injected into the main chamber 10 ignites and burns the air-fuel mixture in the main chamber 10. In this way, the main chamber 10 and the sub chamber 20 form an integrated combustion chamber.

(2) Configuration for Relative Movement of Partition Wall 21 and Closure Wall 40 In the above-mentioned sub-chamber internal combustion engine 1, if the closure wall 40 can move relative to the partition wall 21 of the sub-chamber 20, the specific configuration for that is The closing wall 40 may move, and the partition wall 21 may move, without particular limitation. In this embodiment, the partition wall 21 is movable, while the closing wall 40 is fixed to the inner wall of the main chamber 10.

The partition wall 21 of the sub chamber 20 has a protrusion position (FIG. 2B) and a protrusion amount that maximizes the protrusion amount (in other words, the protrusion amount from the cylinder head 13) of the partition wall 21 toward the combustion space 100 of the main chamber 10. It is movable to and from the minimum burial position (FIG. 2A). On the other hand, the closing wall 40 is fixed to the inner wall (specifically, the cylinder head 13) of the main chamber 10.

When the partition wall 21 moves to the protruding position, as shown in FIG. 2B, the second passage 25 is closed by one of the closing portions 43 of the closing wall 40, and the first passage 23 overlaps with the gangway 41. Further, when the partition wall 21 moves to the buried position, as shown in FIG. 2A, the first connecting passage 23 is closed by the other closing portion 43 of the closing wall 40, and the second connecting passage 25 penetrates the closing wall 40. It overlaps with the road 41.

Then, as shown in FIG. 3, the displacement mechanism 50 moves the partition wall 21 to the protruding position in the compression stroke and the expansion stroke, while moving the partition wall 21 to the buried position in the exhaust stroke and the intake stroke. The displacement cam 51 of the displacement mechanism 50 rotates to the rotation position where the maximum lift amount is obtained in the compression and expansion strokes, and rotates to the rotation position where the minimum lift amount is obtained in each exhaust and intake strokes. And the transmission unit 55 transmits the reciprocating motion of the distance from the maximum lift amount to the minimum lift amount to the partition wall 21 to move the partition wall 21.

(3) Action Effect The sub-chamber internal combustion engine 1 in the above embodiment changes the opening area of the communication passage by relatively moving the closing wall 40 according to the progress of the intake, compression, expansion, and exhaust strokes. Then, the opening area of the communication passage in the exhaust and intake strokes is expanded more than the opening area of the communication passage in the compression stroke and the expansion stroke (see FIG. 3). In this way, scavenging of the auxiliary chamber is promoted in the exhaust stroke and the intake stroke.

Further, in the sub-chamber type internal combustion engine 1, it is sufficient that a part of the closed wall continuous passage is closed by the closed wall 40, and the restriction on the position of the closed wall passage is removed.

Further, in the sub-chamber type internal combustion engine 1, the sub-chamber 20 and the closing wall 40 have a double structure in which the tubular sub-chamber 20 is surrounded by the tubular closing wall 40, and the partition wall of the sub-chamber 20 is formed. 21 has two communication passages having different cross sections. Therefore, the closing wall 40 moves relative to each other, exposing one communication passage and closing the other communication passage, so that the opening area of the communication passage changes.

Further, in the sub-chamber type internal combustion engine 1, the closing wall 40 moves relative to each other so that the through-passage 41 and the closing portion 43 overlap with the first and

second passages

23 and 25, respectively. No. 40 closes the other passage while exposing one passage.

Further, in the sub-chamber type internal combustion engine 1, the closing wall 40 moves relative to the partition wall 21 by moving the partition wall 21 to the protruding position and the buried position.

Further, in the sub-chamber type internal combustion engine 1, the displacement cam 51 and the subsection 53 relatively move the closing wall 40 and the partition wall 21.

(4) Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. In particular, the configurations described herein can be arbitrarily combined as needed.

For example, in the above embodiment, in order for the closing wall 40 to expose and close the communication passage, one of the set of communication passages including the first communication passage 23 and the second communication passage 25 is exposed and the other is closed. Let me. However, in order for the blocking wall 40 to expose and block the communication passage, the entire single communication passage is exposed or partially closed, and the opening area of the single communication passage is defined as the first area and the second communication area. May vary between.

Further, in the above embodiment, the sub chamber 20 and the closing wall 40 have a double structure in which the tubular sub chamber 20 is surrounded by the tubular closing wall 40, and the closing wall 40 projects from the sub chamber 20. By moving relative to each other along the direction, the opening area of the communication passage changes.

However, in order to change the opening area of the communication passage, for example, the closing wall 40 can rotate about the axis direction in which the sub chamber 20 extends, and the partition wall 21 is a plane intersecting the axis of the sub chamber 20. It may have a plurality of communication passages arranged along a direction that visually surrounds this axis. In this configuration, the closing wall 40 moves relative to each other in the direction around the axis of the sub-chamber 20 to expose one communication passage and close the other communication passage to change the opening area of the communication passage. You may.

Further, in the above embodiment, the closing wall 40 has a single through-passage 41, while the partition wall 21 has a pair of communication passages, but as shown in FIGS. 4A and 4B, the closing wall 40 has a pair of through-passages 41. , 45, while the partition wall 21 may have a single gangway 23.

Further, in the above embodiment, the displacement mechanism 50 has the displacement cam 51 and the subsection 53, but the displacement mechanism 50 may be configured by other components.

Further, in the above embodiment, the shape of the sub chamber is an example of a shape (hemispherical shape, cylindrical shape, etc.) in which the cross section of the plane perpendicular to the cylinder axis direction is circular. However, the shape of the sub-chamber is not limited to this. The cross section may be an ellipse or a regular polygon. From the viewpoint of flame propagation, a symmetrical shape is preferable, but the shape is not limited to this. Geometric expressions such as "diameter direction", "diameter direction", and "tangent line" in the present disclosure can be appropriately understood by those skilled in the art even when the cross section is other than circular. That is, even in an embodiment in which the cross section of the sub chamber is other than circular, those skilled in the art will be able to appropriately apply the features of the present disclosure so as to obtain the same effects as those of the present disclosure.

Further, in the above embodiment, a spark-ignition internal combustion engine in which the air-fuel mixture is ignited by a spark plug provided in the sub chamber is taken as an example. Gasoline is used as a fuel in the internal combustion engine of the present disclosure, but the fuel is not limited to this, and other fuels such as alcohol may be used. Further, the features of the present disclosure are not limited to the spark ignition internal combustion engine, and can be applied to a compression ignition internal combustion engine such as a diesel engine. In other words, it is not essential to provide a spark plug or other spark generating means in the sub-chamber, and it is the first normal in one combustion cycle of an internal combustion engine (in the case of a 4-stroke engine, a cycle consisting of intake, compression, combustion, and exhaust). Similar effects can be expected if the internal combustion engine is designed so that combustion (pre-combustion) occurs in the sub-chamber. It is well known that even in a compression ignition internal combustion engine, pre-combustion can be generated in the sub-chamber by injecting fuel directly from the injector into the sub-chamber or by setting the compression ratio appropriately. Further, even in the case of a compression ignition internal combustion engine, the fuel is not particularly limited to light oil, and may be gasoline, alcohol, or the like.

According to the embodiment of the present disclosure, the sub-chamber internal combustion engine (1) is
A sub-chamber internal combustion engine that repeats intake, compression, expansion, and exhaust strokes.
A main chamber (10) defined by a cylinder head (13), a cylinder (11), and a piston (15),
A sub-chamber (20) protruding from the cylinder head (13) toward the main chamber (10) and separated from the main chamber (10) by a partition wall (21).
A communication passage (23, 25) that penetrates the partition wall (21) and communicates the sub chamber (20) and the main chamber (10).
A closing wall (40) provided inside the main chamber (10) and outside the sub chamber (20) that partially closes the opening of the communication passages (23, 25).
The relative positions of the partition wall (21) and the closing wall (40) are the first position where a part of the opening of the communication passage (23, 25) is closed and the opening area of the communication passage (23, 25). A displacement mechanism (50) that changes the relative position of the partition wall (21) and the obstruction wall (40) so that is changed between the second position larger than the first position.
With
The displacement mechanism (50) changes the relative position of the partition wall (21) and the closing wall (40) to the first position in the compression stroke and the expansion stroke, while the relative position in the exhaust stroke and the intake stroke. Is changed to the second position.

The communication passages (23, 25) may have a first communication passage (23) and a second communication passage (25) whose cross section is larger than the cross section of the first communication passage (23). Then, the blocking wall (40) may block only the second passage (25) at the first position, while blocking only the first passage (23) at the second position. ..

The first passage (23) and the second passage (25) are arranged adjacent to each other in the protruding direction of the sub chamber (20), and the first passage (23) is arranged from the cylinder head (13). ), And the second passage (25) may be arranged in this order. The closed wall (40) has a gangway (41) having a cross section equal to or larger than the cross section of the second passage (25), and the gangway (41) along the projecting direction of the sub chamber (20). May have closures (43) extending from both sides of the. Then, in the displacement mechanism (50), when the relative position is the first position, the closing portion (43) overlaps with the second passage (25) and closes the second passage (25). While doing so, the gangway (41) overlaps with the first passage (23) to expose the first passage (23), and when the relative position is the second position, the closing portion (43) Overlaps the first passage (23) to block the first passage (23), and the gangway (41) overlaps with the second passage (25) to block the second passage (25). May be exposed.

In the displacement mechanism (50), the relative position is the first position when the protrusion amount of the partition wall (21) is maximum, and the relative position is the relative position when the protrusion amount of the partition wall (21) is minimum. The partition wall (21) may be moved in the protruding direction of the sub chamber (20) so as to be in the second position.

The displacement mechanism (50) rotates according to the progress of the intake, compression, expansion, and exhaust strokes, and rotates to the first rotation position where the lift amount is either the maximum or the minimum in the exhaust and intake strokes. In addition, in the compression and expansion strokes, the displacement cam (51) that rotates to the second rotation position where the lift amount is either the maximum or the minimum, and the displacement cam (51) are driven to the sub chamber. It may have a follow-up (53) that reciprocates a distance from the maximum lift amount to the minimum lift amount along the protrusion direction of (20). Then, the subordinate (53) may directly or indirectly transmit the reciprocating motion to the closed wall (40) or the partition wall (21) to change the relative positions of the two.

This application is based on Japanese Patent Application No. 2019-061130 filed on March 27, 2019, the contents of which are incorporated herein by reference.

1 ... Sub-chamber type internal combustion engine 10 ... Main chamber 11 ... Cylinder 13 ... Cylinder head 15 ... Piston 20 ... Sub-chamber 21 ... Partition 23 ... First communication passage 25 ... Second communication passage 30 ... Spark plug 31 ... Electrode 33 ... Electrode 40 ... Blocking wall 41 ... Through passage 43 ... Blocking part 50 ... Displacement mechanism 51 ... Displacement cam 53 ... Follower 55 ... Transmission part 100 ... Combustion space 110 ... Intake valve 120 ... Intake port 130 ... Exhaust valve 140 ... Exhaust port 150 ... Injection valve 210 ... Intake cam 220 ... Exhaust cam 230 ... Timing belt

Claims

A sub-chamber internal combustion engine that repeats intake, compression, expansion, and exhaust strokes.
A main chamber defined by a cylinder head, a cylinder, and a piston,
A sub chamber that protrudes from the cylinder head toward the main chamber and is separated from the main chamber by a partition wall.
A communication passage that penetrates the partition wall and connects the sub chamber and the main chamber,
A closing wall provided in the main chamber and outside the sub chamber to partially block the opening of the passageway, and
The relative position of the partition wall and the closed wall changes between the first position where a part of the opening of the communication passage is closed and the second position where the opening area of the communication passage is larger than the first position. A displacement mechanism that changes the relative position of the partition wall and the closed wall so as to
With
The displacement mechanism changes the relative position of the partition wall and the closed wall to the first position in the compression stroke and the expansion stroke, while changing the relative position to the second position in the exhaust stroke and the intake stroke.
Sub-chamber internal combustion engine.
The communication passage has a first passage and a second passage whose cross section is larger than the cross section of the first passage.
The sub-chamber internal combustion engine according to claim 1, wherein the closed wall closes only the second passage at the first position, and closes only the first passage at the second position.
The first passage and the second passage are arranged adjacent to each other in the projecting direction of the sub chamber, and are arranged in this order from the cylinder head to the first passage and the second passage.
The gangway wall has a gangway having a cross section equal to or larger than the cross section of the second passage, and a gangway extending from both sides of the gangway along the projecting direction of the sub chamber.
In the displacement mechanism, when the relative position is the first position, the closing portion overlaps with the second passage and closes the second passage while the through passage overlaps with the first passage. When the first passage is exposed and the relative position is the second position, the closing portion overlaps with the first passage to block the first passage, and the through passage is the second passage. The sub-chamber internal combustion engine according to claim 2, wherein the second continuous passage is exposed so as to overlap the passage.
The displacement mechanism is such that the relative position becomes the first position when the protrusion amount of the partition wall is maximum, and the relative position becomes the second position when the protrusion amount of the partition wall is minimum. The partition wall is moved in the protruding direction of the sub chamber.
The sub-chamber internal combustion engine according to claim 3.
The displacement mechanism is
It rotates according to the progress of the intake, compression, expansion and exhaust strokes, and in the exhaust and intake strokes, it rotates to the first rotation position where the lift amount is either the maximum or the minimum, and the compression and expansion In the stroke, a displacement cam that rotates to the second rotation position where the lift amount is either the maximum or the minimum, and
It has a slave that reciprocates the distance from the maximum lift amount to the minimum lift amount along the projecting direction of the sub chamber in accordance with the displacement cam.
The follower transmits its reciprocating motion directly or indirectly to the obstruction wall or partition wall to change the relative position of the two.
The sub-chamber internal combustion engine according to any one of claims 1 to 4.