WO2020196210A1

WO2020196210A1 - Auxiliary chamber type internal combustion engine

Info

Publication number: WO2020196210A1
Application number: PCT/JP2020/012160
Authority: WO
Inventors: 欣也井上; 田中　大; 貴之城田; 一成野中; 晃弘津田; 遼太朝倉; 捷飯塚; 佳博菅田
Original assignee: 三菱自動車工業株式会社
Priority date: 2019-03-27
Filing date: 2020-03-18
Publication date: 2020-10-01
Also published as: JPWO2020196210A1; JP7143935B2

Abstract

This auxiliary chamber type internal combustion engine is provided with a main chamber, an auxiliary chamber, and communicating passages. The main chamber is defined by a cylinder head, a cylinder, and a piston. The auxiliary chamber projects from the cylinder head toward the main chamber, and is separated from the main chamber. The communicating passages provide communication between the main chamber and the auxiliary chamber, and have injection openings for injecting a flame generated in the auxiliary chamber into the main chamber. The injection openings are configured to guide the flame in the opposite direction to the direction of rotation of a swirling flow generated in the main chamber.

Description

Sub-chamber internal combustion engine

This disclosure relates to a sub-chamber internal combustion engine.

Conventionally, a sub-chamber type internal combustion engine having a main chamber and a sub-chamber provided adjacent to the main chamber has been proposed (see, for example, Japanese Patent No. 4561522). 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. By injecting the flame formed in the sub chamber into the main chamber in this way, the combustion speed of the main chamber is increased. This enables operation with a leaner air-fuel ratio and improves fuel efficiency.

In the sub-chamber internal combustion engine described in Japanese Patent No. 4561522, the central axis of the first injection port is inside the cylinder without colliding with the piston crown surface when the piston is near the compression top dead center. Orient the wall. Further, the central axis of the second injection port points to the outer peripheral portion of the bottom surface of the cavity on the crown surface of the piston when the piston is near the compression top dead center.

However, in the sub-chamber internal combustion engine described in Japanese Patent No. 4561522, the injection port faces the inner wall surface of the cylinder. Therefore, the flame collides with the inner wall surface of the cylinder, and the heat of the flame is taken to the inner wall surface of the cylinder. As a result, a cooling loss occurs and the combustion speed of the main chamber becomes slow.

The embodiment of the present disclosure relates to a sub-chamber type internal combustion engine in which the flame injected from the sub-chamber toward the main chamber is suppressed from colliding with the cylinder and the occurrence of cooling loss is reduced.

According to the embodiment of the present disclosure, the sub-chamber internal combustion engine includes a main chamber, a sub-chamber, and a continuous passage. 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. The communication passage has an injection port that connects the main room and the sub-chamber and injects the flame generated in the sub-chamber into the main room. The injection port is configured to guide the flame in the direction opposite to the direction of rotation of the swirling flow generated in the main chamber.

In general, it is widely known that a swirling flow called a swirl or the like is generated by the intake air introduced into the combustion chamber. Also, various techniques for promoting the generation of a swirling flow in order to improve the combustion efficiency are widely known. In the internal combustion engine according to the embodiment of the present disclosure, the injection port of the communication passage is configured to guide the flame in the direction opposite to the rotation direction of the swirling flow. As a result, the injection direction of the flame injected from the injection port into the main chamber faces the rotation direction of the swirling flow. As a result, the flame injected from the injection port into the main chamber is disturbed and diffused by the swirling flow. As a result, the flame is prevented from colliding with the cylinder, and the heat of the flame is reduced. Therefore, the occurrence of cooling loss is reduced.

The injection port may extend toward the main chamber in the direction opposite to the direction of rotation of the swirling flow.

According to this configuration, the flame injected from the injection port into the main chamber is easily diffused by the swirling flow.

The inner diameter of the injection port may be increased as it approaches the main chamber.

The larger the area of the injection port of the communication passage that injects the flame into the main room, the wider the injected flame and the larger the diameter of the flame. If the area of the injection port is small, the flame is narrowed down and the injection amount of the flame is reduced. According to this configuration, the area of the injection port is increased by increasing the inner diameter of the injection port as it approaches the main chamber. As a result, the diameter of the flame ejected from the communication passage is increased, and the amount of flame passing through the communication passage is prevented from being reduced.

The communication passage may have an inner wall surface formed along the tangent line of the inner wall of the sub chamber when viewed in the direction of the rotation axis of the swirling flow.

According to this configuration, the air-fuel mixture introduced into the sub-chamber from the connecting passage is guided to the inner circumference of the wall. As a result, the air-fuel mixture tends to form a vortex in the sub-chamber. Therefore, unevenness of the air-fuel mixture in the sub-chamber and variation in the flow of the air-fuel mixture are prevented. As a result, the air-fuel mixture in the sub-chamber is easily ignited.

The diameter of the inner circumference of the wall may increase from the main chamber toward the cylinder head.

According to this configuration, the flow velocity of the air-fuel mixture introduced into the sub-chamber from the communication passage decreases toward the cylinder head. That is, the flow velocity of the vortex of the air-fuel mixture weakens. This prevents misfire due to the flow velocity of the air-fuel mixture being too high.

The vertical sectional view which shows the schematic structure of the auxiliary chamber type internal combustion engine by one Embodiment of this disclosure. The cross-sectional view which shows the formation part of the communication passage of the auxiliary chamber type internal combustion engine of FIG. The vertical sectional view which shows the formation part of the communication passage of the auxiliary chamber type internal combustion engine of FIG. The schematic diagram for demonstrating the state of the air-fuel mixture in the intake stroke and the compression stroke of the auxiliary chamber type internal combustion engine of FIG. The schematic diagram for demonstrating the state of the flame of the air-fuel mixture after ignition of the subchamber type internal combustion engine of FIG. The vertical sectional view which shows the schematic structure of the auxiliary chamber by another embodiment of this disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following specification, the cylinder axial direction Q indicates the sliding direction of the piston along the cylinder. When described as the vertical direction, the cylinder axial direction Q is indicated, and the cylinder head side is "up" and the piston side is "down". Further, the left-right direction L indicates a direction orthogonal to the cylinder axial direction Q and where the intake port and the exhaust port are arranged. Further, the crankshaft direction P indicates a direction in which the cylinders are arranged, orthogonal to the cylinder shaft direction Q.

As shown in FIG. 1, the sub-chamber internal combustion engine 1 has a main chamber 4, a sub-chamber 6, a plurality of communication passages 8 communicating the main chamber 4 and the sub-chamber 6, and ignition provided in the sub-chamber 6. It includes a plug 10, a fuel injection valve 12, and a swirling flow generating unit 14. In the present embodiment, the sub-chamber internal combustion engine 1 is an in-line internal combustion engine in which a plurality of cylinders N including a main chamber 4 and a sub chamber 6 are arranged in series. That is, the main chamber 4, the sub chamber 6, the plurality of communication passages 8, the spark plug 10, and the fuel injection valve 12 are provided in each cylinder N. However, the arrangement of the cylinders N is not limited to this, and may be a V type or a horizontally opposed type.

The main chamber 4 is a space defined by the cylinder 101a of the cylinder block 101, the cylinder head 102, and the piston 103. In the present embodiment, the main chamber 4 has a pent roof shape and has two slopes toward the intake port 105 side and the exhaust port 110 side of the cylinder head 102. The main chamber 4 is connected to the intake port 105 via two intake valves 104a and an intake valve 104b driven by an intake cam (not shown). The intake port 105 is connected to an intake passage, a throttle valve, and an air cleaner (not shown). Further, the main chamber 4 has an exhaust port 110, an exhaust passage (not shown), and an exhaust purification catalyst (not shown) via two

exhaust valves

109a and 109b driven by an exhaust cam (not shown). (Not shown) is connected. The sub-chamber internal combustion engine 1 outputs power by a crankshaft (not shown) provided in the arrangement direction of the cylinders N. The piston 103 drives the crankshaft via a connecting rod (not shown).

The sub chamber 6 is provided at the top of the pent roof shape and is adjacent to the main chamber 4. The sub-chamber 6 is a space defined by the sub-chamber wall 61. The sub chamber 6 projects from the cylinder head 102 toward the main chamber 4 and is separated from the main chamber 4 via the sub chamber wall 61. In the present embodiment, the sub chamber 6 is provided substantially at the center of the line of intersection (ridge line) of the two slopes of the main chamber 4 having a pent roof shape. However, the sub chamber 6 may be provided offset from the substantially center of the main chamber 4. In this embodiment, the sub chamber 6 has the same center X1 as the main chamber 4. The volume of the sub chamber 6 is smaller than that of the main chamber 4, and the flame of the air-fuel mixture ignited by the spark plug 10 quickly propagates into the sub chamber 6.

FIG. 2 is a view of the cross section of the sub chamber 6 in the forming portion of the communication passage 8 as viewed from the piston 103 side. As shown in the enlarged view of FIG. 1 and FIG. 2, the auxiliary chamber wall 61 has a circular cross section centered on the center X1, and the bottom portion 61a is formed in a hemispherical shape. FIG. 3 is a vertical cross-sectional view of the forming portion of the communication passage 8 perpendicular to the left-right direction L. As shown in FIG. 3, the diameter Dr of the inner circumference 61c of the sub chamber wall 61 increases from the main chamber 4 side toward the cylinder head 102 side. That is, the diameter Dr of the inner circumference 61c of the auxiliary chamber wall 61 increases from the lower side to the upper side in the vertical direction (same as the cylinder axial direction Q).

As shown in FIGS. 2 and 3, a plurality of communication passages 8 are provided at the bottom 61a of the sub chamber wall 61. The communication passage 8 communicates the main chamber 4 and the sub chamber 6 and guides the air-fuel mixture of the main chamber 4 to the sub chamber 6. The air-fuel mixture introduced into the sub chamber 6 ignites in the sub chamber 6 and precombusts. As shown in FIG. 2, the communication passage 8 has an injection port 8a for injecting a flame precombusted in the sub chamber 6 on the surface of the outer circumference 61b of the sub chamber wall 61. The injection port 8a is formed along the surface of the outer circumference 61b of the sub chamber wall 61. Further, the communication passage 8 has an introduction port 8b for introducing the air-fuel mixture into the sub-chamber 6 on the surface of the inner circumference 61c of the sub-chamber wall 61. The introduction port 8b is formed along the surface of the inner circumference 61c of the auxiliary chamber wall 61. In the present embodiment, for example, four communication passages 8 are provided.

The injection port 8a of the communication passage 8 guides the flame injected from the injection port 8a in the direction U opposite to the rotation direction F of the swirling flow SW generated in the main chamber 4 along the outer circumference 61b of the sub chamber wall 61. In the present embodiment, the injection port 8a extends in the opposite direction U toward the main chamber 4. Here, the flame injected from the injection port 8a is injected along the center line C1 of the injection port 8a. Further, the swirling flow SW flows along the tangent line S1 at the intersection O1 between the center line C1 and the outer circumference 61b. When the communication passage 8 extends along the direction U opposite to the rotation direction F of the swirling flow SW, the center line C1 (including the extension line of the center line C1) is in the direction U opposite to the perpendicular line R1 at the intersection O1. Say to incline. That is, the angle formed by the tangent line S1 and the center line C1 is an obtuse angle A. It is sufficient that at least the injection port 8a extends in the opposite direction U, and the communication passage 8 may extend in the radial direction of the sub chamber 6, for example, except for the injection port 8a.

The communication passage 8 includes an inner wall surface 8c located outside the sub chamber 6 (inner wall surface on the side far from the center X1 in the crankshaft direction P or the left-right direction L) and an inner wall surface located inside the sub chamber 6. It has 8d (inner wall surface on the side closer to the center X1 in the crankshaft direction P or the left-right direction L). The inner wall surface 8c and the inner wall surface 8d of the communication passage 8 face each other in the opposite direction U of the rotation direction F of the swirling flow SW, and the inner wall surface 8c located outside the sub chamber 6 in the communication passage 8 The inner wall surface 8d located on the upstream side of the opposite direction U and inside the sub chamber 6 is located on the downstream side of the opposite direction U. The inner wall surface 8c located outside the sub chamber 6 is formed along the tangent line S2 of the inner circumference 61c of the sub chamber wall 61. Preferably, the inner wall surface 8c of the communication passage 8 is formed from the introduction port 8b to the injection port 8a along the tangent line S2. As a result, there is no step between the injection port 8a and the introduction port 8b, and between the introduction port 8b and the surface of the inner circumference 61c of the sub chamber 6. Therefore, when the air-fuel mixture is introduced into the sub chamber 6 during the compression stroke, the pressure loss generated by the step is suppressed. As a result, a spiral lateral vortex is smoothly formed in the sub chamber 6 along the plane perpendicular to the projecting direction of the sub chamber 6. Further, the communication passage 8 may be formed so as to be inclined in the vertical direction from the main chamber 4 as shown in FIG. 3 and to be inclined in the radial direction as shown in FIG. As a result, the lateral vortex rises in the sub-chamber 6.

Further, as shown in FIG. 2, the inner diameter of the injection port 8a of the communication passage 8 increases as it approaches the main chamber 4. More specifically, the inner diameter Da at the injection port 8a of this space is larger than the inner diameter Db at the introduction port 8b of the space formed by the outer inner wall surface 8c and the inner inner wall surface 8d of the communication passage 8. The inner diameter of the communication passage 8 gradually increases from the introduction port 8b to the injection port 8a. Therefore, the area along the outer circumference 61b of the injection port 8a is larger than the area along the inner circumference 61c of the introduction port 8b. As a result, it is possible to prevent the amount of flame injected through the communication passage 8 from being reduced. Further, the inner diameter of the injection port 8a expands in the direction U opposite to the rotation direction F of the swirling flow SW. That is, the inner wall surface 8d is inclined in the opposite direction U (direction in which the inner diameter of the injection port 8a is expanded) with respect to the inner wall surface 8c. As a result, the flame injected from the injection port 8a directs in a direction along the direction U opposite to the rotation direction F of the swirling flow SW. As a result, the flame injected from the injection port 8a is more likely to be disturbed and diffused by the swirling flow SW. At least the inner diameter of the injection port 8a may be expanded in the opposite direction U, and the inner diameter of the communication passage 8 excluding the injection port 8a may be constant, for example. Further, at least at the injection port 8a, the inner wall surface 8d may extend in the opposite direction U from the inner wall surface 8c, and in the communication passage 8 excluding the injection port 8a, the inner wall surface 8d may be parallel to, for example, the inner wall surface 8c.

As shown in FIGS. 1 and 2, the center electrode 10a of the spark plug 10 is arranged at a position overlapping the center X1 of the sub chamber 6. As shown in FIG. 3, the center line C1 of the communication passage 8 intersects the wall surface of the inner circumference 61c of the sub chamber wall 61 of the sub chamber 6 at the position H. Then, the tip portion 10c of the center electrode 10a of the spark plug 10 is arranged at a position higher than the position H.

The fuel injection valve 12 is provided toward the main chamber 4. Further, the fuel injection valve 12 is provided outside the sub chamber 6. In the present embodiment, the fuel injection valve 12 injects fuel directly into the main chamber 4. That is, the sub-chamber internal combustion engine 1 is a direct injection type internal combustion engine. The injection amount and injection timing of the fuel injection valve 12 are controlled. Further, the fuel injection valve 12 is connected to a fuel injection pump (not shown) and a fuel tank. The fuel injection valve 12 is arranged on the intake valve 104 side of the cylinder head 102. In the present embodiment, the air-fuel ratio of the sub-chamber internal combustion engine 1 is set to a value leaner than the stoichiometric air-fuel ratio. That is, the sub-chamber internal combustion engine 1 is operated by lean burn. This improves fuel efficiency.

As shown in FIG. 4, the swirling flow generating unit 14 generates a swirling flow SW that swirls in the rotation direction F in the main chamber 4. In the present embodiment, the swirling flow generating unit 14 generates the swirling flow SW by changing the lift heights of the intake valve 104a and the intake valve 104b. However, the swirling flow generating unit 14 may generate the swirling flow SW depending on the shape of the intake port 105. Further, in the present embodiment, the swirl flow SW is a swirl flow that swirls counterclockwise when viewed from the piston 103 side with respect to a surface perpendicular to the sliding direction (cylinder axial direction Q) of the piston 103. The swirling flow SW swirls along the inner wall surface of the cylinder 101a and swivels along the outer peripheral 61b of the sub chamber wall 61.

In the sub-chamber internal combustion engine 1 configured in this way, in the intake stroke, the intake valve 104a and the intake valve 104b are opened, the piston 103 is lowered, and the intake air is introduced into the main chamber 4 and the sub-chamber 6. .. At this time, a swirling flow SW is generated in the main chamber 4 due to the difference in lift height between the intake valve 104a and the intake valve 104b. Further, in the present embodiment, the intake air is pressurized by a supercharger (not shown). As a result, the pressures in the main chamber 4 and the sub chamber 6 become the same as the pressure of the intake air. In the intake stroke, fuel injection mainly for supplying fuel to the main chamber 4 is performed by the fuel injection valve 12. The injected fuel mixes with the intake air in the main chamber 4 to form an air-fuel mixture. The air-fuel mixture is supplied to the entire main chamber 4 as the piston 103 is lowered.

In the compression stroke, the intake valve 104a and the intake valve 104b are closed and the piston 103 is raised to compress the air-fuel mixture in the main chamber 4. As shown in FIG. 4, when the piston 103 rises in the compression stroke, the air-fuel mixture is introduced from the main chamber 4 to the sub chamber 6 via the communication passage 8. At this time, the air-fuel mixture introduced into the sub-chamber 6 becomes a lateral vortex (see the arrow in the sub-chamber 6 in FIG. 4) that rises by the communication passage 8.

In the present embodiment, the inner wall surface 8c of the communication passage 8 is formed along the tangent line S2 of the inner circumference 61c of the sub-chamber wall 61. As a result, an ascending lateral vortex is generated along the inner circumference 61c in the sub chamber 6, and the spark plug 10 ignites the lateral vortex. On the other hand, the diameter Dr of the inner circumference 61c of the sub chamber wall 61 expands from the main chamber 4 toward the cylinder head 102 (see FIG. 3). As a result, the flow velocity of the lateral vortex in the sub chamber 6 is reduced. As a result, misfire caused by the flow velocity of the lateral vortex in the sub chamber 6 being too high is prevented.

The air-fuel mixture introduced into the sub chamber 6 is ignited and burned by the spark plug 10. As shown in FIG. 5, at this time, the flame G is injected from the injection port 8a. Then, the air-fuel mixture in the main chamber 4 burns, and the pressure rises due to the combustion gas generated by the combustion. As a result, the piston 103 is pushed down and proceeds to the expansion stroke.

In the present embodiment, the injection port 8a of the communication passage 8 extends in the direction U opposite to the rotation direction F of the swirling flow SW generated in the main chamber 4 along the outer circumference 61b of the sub chamber wall 61, and is in the opposite direction U. Lead the flame G to. As a result, the flame G is injected and then faces the swirling flow SW. Therefore, the flame G is disturbed and diffused like the flame G1 by the swirling flow SW. As a result, the flame G1 diffuses into the space V in the main chamber 4 between the flame G and the flame ejected from the adjacent passage 8. In space V, flame G does not reach and combustion tends to be imbalanced. The flame G faces the swirling flow SW and is disturbed and diffused by the swirling flow SW, so that the flame G1 reaches the space V. As a result, the main chamber 4 burns uniformly. Further, the penetrating force of the flame G is weakened by the swirling flow SW, and the flame G is prevented from directly hitting the cylinder 101a. As a result, the cooling loss generated by cooling the flame G by the cylinder 101a is reduced.

Further, in the present embodiment, the inner diameter of the communication passage 8 increases from the inner diameter Db of the communication passage 8 at the introduction port 8b to the inner diameter Da of the communication passage 8 at the injection port 8a. As the inner diameter Da of the injection port 8a increases, the area of the injection port 8a increases. As a result, the diameter of the flame injected from the injection port 8a also increases. Therefore, a large flame G1 is ejected into the space V in the main chamber 4 between the flame G ejected from the communication passage 8 and the flame G injected from the adjacent passage 8. As a result, the combustion of the space V is promoted. Further, the diameter of the injection port 8a increases in the direction U opposite to the rotation direction F of the swirling flow SW. As a result, more flame G faces the swirling flow SW. That is, the number of flames facing the swirling flow SW increases. Therefore, more flame G1 is supplied to the space V. As a result, the combustion of the space V is promoted.

In the exhaust stroke, the exhaust valve 109 opens, the piston 103 rises from the bottom dead center, and the combustion gas (exhaust) in the cylinder is discharged to the exhaust port 110. Then, when the piston 103 reaches top dead center, the intake stroke starts again. When the piston 103 reciprocates twice in this way, four strokes are completed.

As described above, in the sub-chamber internal combustion engine 1 of the present embodiment, the injection port 8a of the communication passage 8 is the rotation direction F of the swirling flow SW generated in the main chamber 4 along the outer circumference 61b of the sub-chamber wall 61. Guide the flame G in the opposite direction U of. As a result, the occurrence of cooling loss of the flame G ejected from the sub chamber 6 toward the main chamber 4 is prevented, and the combustion of the main chamber 4 is promoted.

<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 plurality of modifications described in the present specification can be arbitrarily combined as required.

In the above embodiment, the sub-chamber internal combustion engine 1 is a direct injection type internal combustion engine, but the present disclosure is not limited to this. For example, it may be an auxiliary chamber type internal combustion engine provided with an intake port injector provided at the intake port 105.

In the above embodiment, four communication passages 8 are provided on the sub-chamber wall 61, but the present disclosure is not limited to this. The communication passage 8 may be one or a plurality.

In the above embodiment, the inner diameter of the communication passage 8 increases toward the outer circumference 61b of the sub-chamber wall 61, but the present disclosure is not limited to this. For example, the inner diameter of the communication passage 8 may be constant. That is, the inner diameter Da at the injection port 8a in FIG. 2 and the inner diameter Db at the introduction port 8b may be the same.

In the above embodiment, the communication passage 8 is provided at one position in the protruding direction of the sub chamber 6, but the present disclosure is not limited to this. As shown in FIG. 6, the first passage 208 and the second passage 209 may be provided at different positions in the protruding direction of the sub chamber 6. In this case, the inner diameter of either the first passage 208 or the second passage 209 may be constant. Further, the inner diameter of the other passage may be expanded toward the outer circumference 261b of the sub chamber wall 261. For example, when the first passage 208 is provided closer to the tip 210c of the spark plug 210 than the second passage 209, the inner diameter of the first passage 208 faces the outer circumference 261b of the sub chamber wall 261. May be expanded. On the other hand, the inner diameter of the second passage 209 may be constant. As a result, the amount of flame injected from the first passage 208 near the tip 210c of the spark plug 210 increases.

In the above embodiment, the bottom 61a has a hemispherical shape, but the present disclosure is not limited to this. As shown in FIG. 6, the shape of the bottom portion 261a may be a truncated cone shape. Further, it may have various shapes such as a conical shape.

In the above embodiment, the swirl flow generation unit 14 generates a swirl flow, but the present disclosure is not limited to this. The swirling flow generating unit 14 may generate a vertical vortex that swirls in one direction along a plane parallel to the cylinder axial direction Q, that is, may generate a tumble flow. In this case, the communication passage 8 may be formed along the direction opposite to the rotation direction of the tumble flow.

In the above embodiment, the shape of the sub chamber is an example of a shape (hemispherical shape, cylindrical shape, etc.) having a circular cross section due to a plane perpendicular to the cylinder axis direction. 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.

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 main chamber (4) defined by a cylinder head (102), a cylinder (101a), and a piston (103).
A sub-chamber (6) protruding from the cylinder head (102) toward the main chamber (4) and separated from the main chamber (4).
A communication passage (8) connecting the main room (4) and the sub room (6),
With
The communication passage (8) has an injection port (8a) for injecting a flame generated in the sub chamber (6) into the main chamber (4).
The injection port (8a) is configured to guide the flame in a direction (U) opposite to the rotation direction (F) of the swirling flow (SW) generated in the main chamber (4).

The injection port (8a) may extend in the opposite direction (U) toward the main chamber (4).

The inner diameter (Da) of the injection port (8a) may be enlarged as it approaches the main chamber (4).

The communication passage (8) has an inner wall surface (S2) formed along the tangent line (S2) of the inner circumference (61c) of the sub chamber (6) when viewed in the rotation axis direction of the swirling flow (SW). 8c) may be provided.

The inner diameter (Dr) of the sub chamber (6) may be expanded from the main chamber (4) toward the cylinder head (102).

This application is based on Japanese Patent Application No. 2019-061137 filed on March 27, 2019, the contents of which are incorporated herein by reference.

1: Sub-chamber internal combustion engine 4: Main chamber 6: Sub-chamber 8: Communication passage 8c: Inner wall surface 14: Swirling flow generator 61: Sub-chamber wall 61b: Outer circumference 61c: Inner circumference 101a: Cylinder 102: Cylinder head 103: Piston Da: Inner diameter Db: Inner diameter Dr: Inner circumference diameter F: Swirling flow rotation direction U: Swirling flow rotation direction opposite direction S2: Inner circumference tangent SW: Swirling flow

Claims

A main chamber defined by a cylinder head, a cylinder, and a piston,
An auxiliary chamber that protrudes from the cylinder head toward the main chamber and is separated from the main chamber.
A communication passage connecting the main room and the sub room,
With
The communication passage has an injection port for injecting a flame generated in the sub chamber into the main chamber.
The injection port is a sub-chamber type internal combustion engine configured to guide the flame in a direction opposite to the rotation direction of a swirling flow generated in the main chamber.
The injection port extends in the opposite direction toward the main chamber.
The sub-chamber internal combustion engine according to claim 1.
The inner diameter of the injection port expands as it approaches the main chamber.
The sub-chamber internal combustion engine according to claim 1 or 2.
The communication passage has an inner wall surface formed along the tangent line of the inner circumference of the sub chamber when viewed in the rotation axis direction of the swirling flow.
The sub-chamber internal combustion engine according to any one of claims 1 to 3.
The inner diameter of the sub chamber expands from the main chamber toward the cylinder head.
The sub-chamber internal combustion engine according to any one of claims 1 to 4.