engine

Abstract

This engine comprises: a piston; a cylinder block having cylinders in which the piston performs a reciprocating motion; a cylinder head that is fixed to the cylinder block and that forms a main chamber between the cylinder head and the piston; a dividing wall that is provided on the main chamber side of the cylinder head and that forms a secondary chamber inside the main chamber; and an ignition plug installed inside the secondary chamber. The dividing wall has a swirl flow-generating communication path that is provided inclined in a direction toward the center of the secondary chamber in the circumferential direction of the cylinder and that leads from the main chamber to the secondary chamber; a flame injection communication path that is provided straight toward the center of the secondary chamber in the circumferential direction of the cylinder and that leads from the secondary chamber to the main chamber; and a suppression means for suppressing flame injection from the swirl flow-generating communication path.

Description

[Technical Field]

[0001] The present disclosure relates to engines. [Background technology]

[0002] Patent Document 1 discloses an engine in which an air-fuel mixture is burned in an auxiliary chamber and flames are injected into the main chamber through injection holes that open from the auxiliary chamber to the main chamber. In this engine, the intake port that introduces fresh air into the main chamber is formed as a swirl port that generates a swirling flow of the fresh air in the main chamber, and the direction of the flame injection from the injection hole is the swirling direction relative to the axis of the main chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-232987 Summary of the Invention [Problem to be solved by the invention]

[0004] In the engine disclosed in Patent Document 1, a swirl flow is generated in the pre-chamber by the fresh air flowing into the pre-chamber, and the flame ignited in the pre-chamber also swirls on the swirl flow in the pre-chamber. As a result, when the flame is injected from the pre-chamber to the main chamber, the flame separates from the inner wall of the injection hole, making the effective diameter of the injection hole smaller than it actually is, and reducing the injection energy of the flame injected from the injection hole.

[0005] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide an engine that can generate a swirl flow in an auxiliary chamber and can suppress a decrease in flame injection energy. [Means for solving the problem]

[0006] (1) An engine according to at least one embodiment of the present invention comprises a cylinder block having a piston and a cylinder in which the piston reciprocates, a cylinder head fixed to the cylinder block and forming a main chamber between the piston and the cylinder block, a partition wall provided on the main chamber side of the cylinder head and forming an auxiliary chamber within the main chamber, and an ignition plug installed within the auxiliary chamber, wherein the partition wall is inclined in the circumferential direction of the cylinder toward the center of the auxiliary chamber and has a swirl flow generating communication passage leading from the main chamber to the auxiliary chamber, a flame injection communication passage provided straight in the circumferential direction of the cylinder toward the center of the auxiliary chamber and leading from the auxiliary chamber to the main chamber, and suppression means for suppressing flame injection from the swirl flow generating communication passage.

[0007] According to the above configuration (1), the suppression means suppresses the injection of flame from the swirl flow generating communication passage, so the injection energy of the flame from the flame injection communication passage increases and the decrease in the injection energy of the flame from the flame injection communication passage can be suppressed. This makes it possible to generate a swirl flow in the pre-chamber and suppress the decrease in the injection energy of the flame.

[0008] (2) In some embodiments, in the configuration of (1) above, the suppression means is such that the maximum flow path cross-sectional area of ​​the swirl flow generating communication passage is smaller than the minimum flow path cross-sectional area of ​​the flame injection communication passage.

[0009] According to the above configuration (2), the maximum flow path cross-sectional area of ​​the swirl flow generating communication passage is made smaller than the minimum flow path cross-sectional area of ​​the flame injection communication passage, so that the injection of flame from the swirl flow generating communication passage is suppressed and the injection energy of the flame from the flame injection communication passage is increased, thereby suppressing a decrease in the injection energy of the flame from the flame injection communication passage.

[0010] (3) In some embodiments, in the configuration of (1) or (2) above, the suppression means makes the distance from the swirl flow generating passage to the spark plug longer than the distance from the flame injection passage to the spark plug.

[0011] According to the configuration (3) above, the distance from the swirl flow generating passage to the spark plug is longer than the distance from the flame injection passage to the spark plug, so flame injection from the swirl flow generating passage is suppressed and the injection energy of the flame from the flame injection passage is increased, thereby making it possible to suppress a decrease in the injection energy of the flame from the flame injection passage.

[0012] (4) In some embodiments, in any one of the configurations (1) to (3) above, the suppression means is an obstacle provided between the spark plug and the swirl flow generating communication passage.

[0013] According to the above configuration (4), the obstacle obstructs the flame flowing from the spark plug to the swirl flow generating communication passage, suppressing the flame from being injected from the swirl flow generating communication passage and increasing the injection energy of the flame from the flame injection communication passage, thereby suppressing a decrease in the injection energy of the flame from the flame injection communication passage.

[0014] (5) In some embodiments, in any one of the configurations (1) to (4) above, the suppression means is such that the swirl flow generating communication passage is longer than the flame injection communication passage.

[0015] According to the configuration (5) above, the swirl flow generating communication passage is made longer than the flame injection communication passage, so that the injection of flame from the swirl flow generating communication passage is suppressed and the injection energy of the flame from the flame injection communication passage is increased, thereby suppressing a decrease in the injection energy of the flame from the flame injection communication passage.

[0016] (6) In some embodiments, in any one of the configurations (1) to (5) above, the partition has an auxiliary chamber base where the ignition point of the spark plug and the flame injection communicating passage are provided, and an auxiliary chamber tip portion which is provided on the piston side of the auxiliary chamber base and where the swirl flow generating communicating passage is provided, and the suppression means makes the volume of the auxiliary chamber tip portion smaller than the volume of the auxiliary chamber base.

[0017] According to the configuration (6) above, the volume of the pre-chamber tip is smaller than the volume of the pre-chamber base, so the flame separates at the boundary between the pre-chamber base and the pre-chamber tip. This makes it difficult for the flame to flow from the pre-chamber base to the pre-chamber tip, and suppresses flame injection from the swirl flow generating communication passage provided at the pre-chamber tip. As a result, the injection energy of the flame from the flame injection communication passage provided at the pre-chamber base increases, and a decrease in the injection energy of the flame from the flame injection communication passage can be suppressed.

[0018] (7) In some embodiments, in any one of the configurations (1) to (6) above, an injection nozzle is provided that injects fuel into the main chamber, and the swirl flow generating communication passage is provided in the circumferential direction of the cylinder from the auxiliary chamber toward the main chamber on the side opposite to the side on which the injection nozzle is provided.

[0019] According to the configuration of (7) above, the swirl flow generating passage is arranged in the circumferential direction of the cylinder from the auxiliary chamber toward the main chamber, facing the opposite side to the side where the injection nozzle is provided. This makes it possible to suppress the generation of a flow of a mixture containing a large amount of fuel on the partition wall side of the auxiliary chamber, and to stratify the interior of the auxiliary chamber. [Effects of the Invention]

[0020] According to at least one embodiment of the present invention, it is possible to generate a swirl flow in the pre-chamber and suppress a decrease in the injection energy of the flame. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view schematically showing the overall configuration of an engine. [Figure 2A] FIG. 2 is a cross-sectional view schematically showing the partition wall and the spark plug shown in FIG. [Figure 2B] 2B is a cross-sectional view of the partition wall shown in FIG. 2A in the direction BB. [Figure 2C] 2B is a cross-sectional view of the partition wall shown in FIG. 2A taken along the CC direction. [Figure 3]FIG. 10 is a cross-sectional view showing an example of a partition wall and an ignition plug of an engine according to a third embodiment. [Figure 4] FIG. 10 is a cross-sectional view schematically showing a partition wall and an ignition plug of an engine according to a sixth embodiment. [Figure 5] FIG. 11 is a schematic diagram illustrating a partition wall and an injection nozzle of an engine according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative positions, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0023] [Embodiment 1] [Overall engine configuration] As shown in FIG. 1, an engine 1A according to the first embodiment includes a piston 10, a cylinder block 12, a cylinder head 14, a partition wall 16, an injection nozzle 18, and a spark plug 20. The cylinder block 12 includes a cylinder 22 in which the piston 10 reciprocates. The cylinder head 14 is fixed to the cylinder block 12 and defines a main chamber (combustion chamber) 24 between the piston 10 and the cylinder head 14. The cylinder head 14 includes an intake port 26 and an exhaust port 28. For example, two intake ports 26 and two exhaust ports 28 are provided for each main chamber 24, but this is not limited to this. The intake port 26 is provided with an intake valve 30 that opens and closes the intake port 26, and the exhaust port 28 is provided with an exhaust valve 32 that opens and closes the exhaust port 28. For example, the intake port 26 is provided with an injection nozzle 34 (hereinafter referred to as a "port injector 34") that injects fuel, but the port injector 34 is not essential. The partition wall 16 is provided on the main chamber side of the cylinder head 14 and defines a pre-chamber (pre-combustion chamber) 36 within the main chamber. The injection nozzle 18 (hereinafter referred to as the "direct injector 18") is an injection nozzle that injects fuel into the main chamber. The spark plug 20 is installed in the pre-chamber and is capable of igniting the air-fuel mixture that flows into the pre-chamber.

[0024] [Engine 1A overall operation] In the engine 1A according to the first embodiment, the port injector 34 injects fuel during the intake stroke when the intake valve 30 opens the intake port 26 and the piston 10 descends. As a result, an air-fuel mixture is supplied from the intake port 26 to the main combustion chamber 24. In the engine 1A according to the first embodiment, the air-fuel mixture in the main combustion chamber becomes leaner than the stoichiometric air-fuel ratio.

[0025] During the compression stroke when the intake valve 30 closes the intake port 26 and the piston 10 rises, the direct injector 18 injects fuel. As a result, the fuel injected from the direct injector 18 is supplied to the auxiliary combustion chamber 36 together with the air-fuel mixture in the main combustion chamber. In the engine 1A according to the first embodiment, the air-fuel mixture in the auxiliary combustion chamber has a ratio close to the stoichiometric air-fuel ratio.

[0026] During the expansion stroke, when the piston 10 descends, the air-fuel mixture in the pre-chamber is ignited by the spark plug 20. This causes the air-fuel mixture in the pre-chamber to turn into a flame, which is then injected into the main chamber, causing the air-fuel mixture in the main chamber to combust.

[0027] During the exhaust stroke, the exhaust valve 32 opens the exhaust port 28 and the piston 10 rises, expelling the combustion gases from the main chamber. The engine 1A operates by repeating the intake stroke, compression stroke, expansion stroke, and exhaust stroke.

[0028] [Configuration of bulkhead 16] As shown in Fig. 2A, the partition wall 16 has an outer shape shaped like a truncated cone. A flange 38 is provided at the large-diameter end of the partition wall 16, and this flange 38 secures the partition wall 16 to the main chamber side of the cylinder head 14. As a result, the large-diameter side of the partition wall 16 forms the base end side that is secured to the cylinder head 14, and the small-diameter side forms the tip side that is located on the piston side. The partition wall 16 contains an auxiliary chamber 36 shaped like a truncated cone. The large-diameter side of the auxiliary chamber 36 forms an auxiliary chamber base 40 that is located on the cylinder head side, and the small-diameter side forms an auxiliary chamber tip 42 that is located on the piston side.

[0029] The partition wall 16 has a swirl flow generating communication passage 44 and a flame injection communication passage 46. The swirl flow generating communication passage 44 is a communication passage that connects the main chamber 24 to the auxiliary chamber 36, and as shown in FIG. 2B, is provided at an angle relative to the direction toward the center O of the auxiliary chamber 36 in the circumferential direction of the cylinder 22 (for example, at an angle θ). The flame injection communication passage 46 is a communication passage that connects the auxiliary chamber 36 to the main chamber 24, and as shown in FIG. 2C, is provided at a different position from the swirl flow generating communication passage 44 in the circumferential direction or extension direction of the cylinder 22. The flame injection communication passage 46 is provided straight toward the center of the auxiliary chamber 36 in the circumferential direction of the cylinder 22.

[0030] The partition wall 16 is also provided with suppression means for suppressing the injection of flames from the swirl flow generating communication passage 44. The suppression means may be any means that suppresses the flames injected from the swirl flow generating communication passage 44 so that they are smaller than the flames injected from the flame injection communication passage 46.

[0031] [Engine 1A operation] In the engine 1A according to the first embodiment, during the compression stroke of the engine 1A, the air-fuel mixture is supplied from the main combustion chamber 24 to the auxiliary combustion chamber 36 through the swirl flow generating communication passage 44 and the flame injection communication passage 46. The air-fuel mixture supplied from the swirl flow generating communication passage 44 swirls along the auxiliary combustion chamber side wall surface 16a of the partition wall 16, generating a swirl flow SF in the auxiliary combustion chamber.

[0032] Next, during the expansion stroke of the engine 1A, the spark plug 20 ignites the air-fuel mixture in the pre-chamber. The air-fuel mixture in the pre-chamber then turns into a flame and is injected into the main chamber through the flame injection communicating passage 46 and the swirl flow generating communicating passage 44. At this time, the injection of flame from the main chamber 24 through the swirl flow generating communicating passage 44 is suppressed by the suppression means. This increases the injection energy of the flame from the flame injection communicating passage 46, and makes it possible to suppress a decrease in the injection energy of the flame from the flame injection communicating passage 46. The flame injected into the main chamber through the flame injection communicating passage 46 and the swirl flow generating communicating passage 44 then combusts the air-fuel mixture in the main chamber.

[0033] [effect] According to the engine 1A of the first embodiment, the suppression means suppresses the injection of flame from the swirl flow generating communication passage 44, so the injection energy of the flame from the flame injection communication passage 46 increases and it is possible to suppress a decrease in the injection energy of the flame from the flame injection communication passage 46. As a result, it is possible to generate a swirl flow SF in the pre-chamber and suppress a decrease in the injection energy of the flame.

[0034] [Embodiment 2] [Engine Configuration] In engine 1B according to the second embodiment, the suppression means is such that the maximum flow path cross-sectional area A1 of the swirl flow generation communication passage 44 is smaller than the minimum flow path cross-sectional area A2 of the flame injection communication passage 46. For example, if the diameters of the swirl flow generation communication passage 44 and the flame injection communication passage 46 are constant, the diameter D1 of the swirl flow generation communication passage 44 is made smaller than the diameter D2 of the flame injection communication passage 46. The other configurations of engine 1B according to the second embodiment are the same as those of engine 1A according to the first embodiment described above.

[0035] [Engine 1B operation] In engine 1B according to the second embodiment, the maximum flow path cross-sectional area A1 of swirl flow generation communication passage 44 is made smaller than the minimum flow path cross-sectional area A2 of flame injection communication passage 46, thereby suppressing the injection of flame from main chamber 24 through swirl flow generation communication passage 44 during the expansion stroke of engine 1B. Other operations of engine 1B according to the second embodiment are the same as those of engine 1A according to the first embodiment described above.

[0036] [effect] In the engine 1B according to the second embodiment, the maximum flow path cross-sectional area A1 of the swirl flow generation communication passage 44 is smaller than the minimum flow path cross-sectional area A2 of the flame injection communication passage 46, so that the injection of flame from the swirl flow generation communication passage 44 is suppressed and the injection energy of the flame from the flame injection communication passage 46 is increased. This makes it possible to suppress a decrease in the injection energy of the flame from the flame injection communication passage 46.

[0037] [Embodiment 3] [Engine Configuration] In engine 1C according to the third embodiment, the suppression means is such that the distance from swirl flow generating communication passage 44 to spark plug 20 is longer than the distance from flame injection communication passage 46 to spark plug 20. As shown in FIG. 2A , when ignition point 48 of spark plug 20 is located in sub-chamber base 40, flame injection communication passage 46 is provided on the base end side of partition wall 16, while swirl flow generating communication passage 44 is provided on the tip end side of partition wall 16, thereby making the distance from swirl flow generating communication passage 44 to spark plug 20 longer than the distance from flame injection communication passage 46 to spark plug 20. 3, when the ignition point 48 of the spark plug 20 is located at the pre-chamber tip 42, a flame injection communicating passage 46 is provided on the tip side of the partition wall 16, and a swirl flow generating communicating passage 44 is also provided on the tip side of the partition wall 16, so that the distance from the swirl flow generating communicating passage 44 to the spark plug 20 is longer than the distance from the flame injection communicating passage 46 to the spark plug 20. The other configurations of the engine 1C according to the third embodiment are the same as those of the engine 1A or 1B according to the first or second embodiment described above.

[0038] [Engine 1C operation] In engine 1C according to the third embodiment, the distance from swirl flow generating communication passage 44 to spark plug 20 is longer than the distance from flame injection communication passage 46 to spark plug 20, thereby suppressing flame injection from main combustion chamber 24 through swirl flow generating communication passage 44 during the expansion stroke of engine 1C. Other operations of engine 1C according to the third embodiment are the same as those of engine 1A or 1B according to the first or second embodiment described above.

[0039] [effect] In the engine 1C according to the third embodiment, the distance from the swirl flow generating communication passage 44 to the spark plug 20 is longer than the distance from the flame injection communication passage 46 to the spark plug 20, which suppresses flame injection from the swirl flow generating communication passage 44 and increases the injection energy of the flame from the flame injection communication passage 46. This makes it possible to suppress a decrease in the injection energy of the flame from the flame injection communication passage 46.

[0040] [Embodiment 4] [Engine Configuration] In the engine 1D according to the fourth embodiment, the suppression means is an obstacle provided between the spark plug 20 and the swirl flow generating communication passage 44. The obstacle is, for example, a canopy-shaped structure, and is arranged to suppress flame injection from the swirl flow generating communication passage 44 during the expansion stroke of the engine 1D. Other configurations of the engine 1D according to the fourth embodiment are the same as those of any of the engines 1A to 1C according to the first to third embodiments described above.

[0041] [Engine 1 Operation] In the engine 1D according to the fourth embodiment, an obstacle provided between the spark plug 20 and the swirl flow generating communication passage 44 suppresses the injection of flame from the main combustion chamber 24 through the swirl flow generating communication passage 44 during the expansion stroke of the engine 1D. Other operations of the engine 1D according to the fourth embodiment are the same as those of any of the engines 1A to 1C according to the first to third embodiments described above.

[0042] [effect] In the engine 1D according to the fourth embodiment, the obstacle obstructs the flame flowing from the spark plug 20 to the swirl flow generating communication passage 44, suppressing the flame from the swirl flow generating communication passage 44 and increasing the injection energy of the flame from the flame injection communication passage 46. This makes it possible to suppress a decrease in the injection energy of the flame from the flame injection communication passage 46.

[0043] [Embodiment 5] [Engine Configuration] In engine 1E according to embodiment 5, the suppression means is that swirl flow generating communication passage 44 is made longer than flame injection communication passage 46. For example, as shown in FIG. 2B, by arranging swirl flow generating communication passage 44 in the tangential direction of sub chamber 36, swirl flow generating communication passage 44 is made longer than flame injection communication passage 46. The other configurations of engine 1E according to embodiment 5 are the same as the configurations of any of engines 1A to 1D according to embodiments 1 to 4 described above.

[0044] [Engine 1E operation] In engine 1E according to embodiment 5, the swirl flow generating communication passage 44 is made longer than the flame injection communication passage 46, thereby suppressing the injection of flame from the auxiliary combustion chamber 36 through the swirl flow generating communication passage 44 during the expansion stroke of engine 1E. Other operations of engine 1E according to embodiment 5 are the same as those of any of engines 1A to 1D according to embodiments 1 to 4 described above.

[0045] [effect] In the engine 1E according to the fifth embodiment, the swirl flow generating communication passage 44 is made longer than the flame injection communication passage 46, so that the injection of flame from the swirl flow generating communication passage 44 is suppressed and the injection energy of the flame from the flame injection communication passage 46 is increased. This makes it possible to suppress a decrease in the injection energy of the flame from the flame injection communication passage 46.

[0046] [Embodiment 6] [Engine Configuration] In the engine 1F according to the sixth embodiment, the ignition point 48 of the spark plug 20 and the flame injection communicating passage 46 are provided in the pre-combustion chamber base 40, the swirl flow generating communicating passage 44 is provided in the pre-combustion chamber tip 42, and the suppression means is that the volume of the pre-combustion chamber tip 42 is made smaller than the volume of the pre-combustion chamber base 40. For example, as shown in FIG. 4 , the pre-combustion chamber base 40, which is shaped like a truncated cone and accommodates the tip of the spark plug 20, is provided on the base end side of the partition wall 16, and the pre-combustion chamber tip 42, which is shaped like a cylinder and has a smaller volume than the pre-combustion chamber base 40, is provided on the tip end side of the partition wall 16. This provides a step surface 50 at the boundary between the pre-combustion chamber base 40 and the pre-combustion chamber tip 42, making the volume of the pre-combustion chamber tip 42 smaller than the volume of the pre-combustion chamber base 40. The other configurations of the engine 1F according to the sixth embodiment are the same as those of any of the engines 1A to 1E according to the first to fifth embodiments described above.

[0047] [Engine 1F operation] In the engine 1F according to the sixth embodiment, the flame separates from the pre-chamber side wall surface 16a at the boundary between the pre-chamber base 40 and the pre-chamber tip 42 during the expansion stroke of the engine 1F, thereby suppressing the flame from being ejected from the pre-chamber 36 through the swirl flow generating communication passage 44. Other operations of the engine 1F according to the sixth embodiment are the same as those of any of the engines 1A to 1E according to the first to fifth embodiments described above.

[0048] [effect] In the engine 1F according to the sixth embodiment, the volume of the pre-combustion chamber tip 42 is smaller than the volume of the pre-combustion chamber base 40, so that the flame separates at the boundary between the pre-combustion chamber base 40 and the pre-combustion chamber tip 42. This makes it difficult for the flame to flow from the pre-combustion chamber base 40 to the pre-combustion chamber tip 42, and suppresses flame injection from the swirl flow generating communication passage 44 provided in the pre-combustion chamber tip 42. As a result, the injection energy of the flame from the flame injection communication passage 46 provided in the pre-combustion chamber base 40 increases, so that a decrease in the injection energy of the flame from the flame injection communication passage 46 can be suppressed.

[0049] [Embodiment 7] [Engine Configuration] In engine 1G according to the seventh embodiment, the suppression means is such that the upstream side in the swirl flow direction of the auxiliary chamber side opening of flame injection communicating passage 46 is curved, while the upstream side of swirl flow generating communicating passage 44 is cornered. For example, the upstream side in the swirl flow direction of the auxiliary chamber side opening of flame injection communicating passage 46 is corner-rounded (so-called R-chamfering), while the auxiliary chamber side opening of swirl flow generating communicating passage 44 is left as is. The other configurations of engine 1G according to the seventh embodiment are the same as the configurations of any of engines 1A to 1F according to the first to sixth embodiments described above.

[0050] [Engine 1G operation] In engine 1G according to the seventh embodiment, the upstream side in the swirl flow direction of the auxiliary chamber opening of flame injection communicating passage 46 is curved, while the upstream side of swirl flow generating communicating passage 44 is angular, so that the flow coefficient of combustion gas injected from flame injection communicating passage 46 is larger than the flow coefficient of combustion gas injected from swirl flow generating communicating passage 44. Other operations of engine 1G according to the seventh embodiment are the same as those of any of engines 1A to 1F according to the first to sixth embodiments described above.

[0051] [effect] In engine 1G according to the seventh embodiment, the upstream side in the swirl flow direction of the auxiliary chamber opening of flame injection communicating passage 46 is curved, while the upstream side of swirl flow generating communicating passage 44 is angular, so the flow coefficient of combustion gas injected from flame injection communicating passage 46 is larger than the flow coefficient of combustion gas injected from swirl flow generating communicating passage 44, and the injection energy of the flame flow from flame injection communicating passage 46 is increased. This makes it possible to suppress a decrease in the injection energy of the flame flow from flame injection communicating passage 46.

[0052] [Embodiment 8] [Engine Configuration] 5, in engine 1H according to the seventh embodiment, the swirl flow generating communication passage 44 is provided in the circumferential direction of the cylinder 22, extending from the auxiliary combustion chamber 36 toward the main combustion chamber 24, on the side opposite to the side where the direct injector 18 is provided. In addition, the swirl flow generating communication passage 44 is provided on the opposite side of the direct injector 18 in the circumferential direction of the cylinder 22. Note that it is sufficient that the swirl flow generating communication passage 44 is provided at least in the circumferential direction of the cylinder 22, extending from the auxiliary combustion chamber 36 toward the main combustion chamber 24, on the side opposite to the side where the injection nozzle 18 is provided, and it may be provided on the direct injector 18 side. The other configurations of engine 1H according to the seventh embodiment are the same as the configurations of any of engines 1A to 1G according to the first to sixth embodiments described above.

[0053] [Engine H operation] In the engine 1H according to the seventh embodiment, fuel injected from the direct injector 18 is prevented from flowing in from the swirl flow generating communication passage 44 during the compression stroke of the engine 1H. This causes the air-fuel mixture flowing in from the swirl flow generating communication passage 44 to generate a swirl flow SF. Other operations of the engine 1H according to the seventh embodiment are the same as those of any of the engines 1A to 1G according to the first to sixth embodiments described above.

[0054] [effect] In the engine 1H according to the seventh embodiment, the swirl flow generating communication passage 44 is provided in the circumferential direction of the cylinder 22, facing from the auxiliary combustion chamber 36 toward the main combustion chamber 24, opposite the side where the direct injector 18 is provided, thereby preventing a flow of a fuel-rich mixture from being generated on the partition wall side of the auxiliary combustion chamber 36, and stratifying the mixture inside the auxiliary combustion chamber. Furthermore, by providing the swirl flow generating communication passage 44 on the opposite side of the direct injector 18 in the circumferential direction of the cylinder 22, it is possible to prevent a fuel-rich mixture from being generated on the partition wall side of the auxiliary combustion chamber 36. [Explanation of symbols]

[0055] 1A~1H Engine 10 pistons 12 Cylinder block 14 Cylinder head 16 Bulkhead 16a 18 Injection nozzle (direct injector) 20 Spark plug 22 cylinders 24 Main room 26 Intake port 28 Exhaust port 30 Intake valve 32 Exhaust valve 34 Injection nozzle (port injector) 36 Antechamber 38 flange 40 Subventricular base 42 Tip of subchamber 44 Swirl flow generation connecting passage 46 Flame injection connecting passage 48 Ignition point 50 Step surface SF Swirl flow

Claims

1. The piston and a cylinder block provided with a cylinder in which the piston reciprocates; a cylinder head fixed to the cylinder block and defining a main chamber between the cylinder head and the piston; a partition wall provided on the main chamber side of the cylinder head and defining an auxiliary chamber within the main chamber; a spark plug disposed in the sub-chamber; Equipped with The partition wall is a swirl flow generating communication passage that is provided inclined with respect to a direction toward the center of the auxiliary chamber in the circumferential direction of the cylinder and that leads from the main chamber to the auxiliary chamber; a flame injection communication passage that is provided straight toward the center of the auxiliary chamber in the circumferential direction of the cylinder and that leads from the auxiliary chamber to the main chamber; a suppression means for suppressing the injection of flames from the swirl flow generating communication passage; An engine having:

2. 2. The engine according to claim 1, wherein the suppression means comprises making the maximum flow passage cross-sectional area of ​​the swirl flow generating communication passage smaller than the minimum flow passage cross-sectional area of ​​the flame injection communication passage.

3. The suppression means is configured to make the distance from the swirl flow generating communication passage to the spark plug longer than the distance from the flame injection communication passage to the spark plug.

3. An engine according to claim 1 or 2.

4. the suppression means is an obstacle provided between the spark plug and the swirl flow generating communication passage. An engine according to any one of claims 1 to 3.

5. The suppression means is configured to make the swirl flow generating communication passage longer than the flame injection communication passage. An engine according to any one of claims 1 to 4.

6. The partition wall is a sub-chamber base portion in which the ignition point of the spark plug and the flame injection communication passage are provided; a pre-chamber tip portion provided on the piston side relative to the pre-chamber base portion and including the swirl flow generating communication passage; and The suppression means is configured to make the volume of the tip end portion of the auxiliary chamber smaller than the volume of the base portion of the auxiliary chamber. An engine according to any one of claims 1 to 5.

7. an injection nozzle for injecting fuel into the main chamber; the swirl flow generating communication passage is provided in a circumferential direction of the cylinder from the auxiliary chamber toward the main chamber, facing away from the side on which the injection nozzle is provided. An engine according to any one of claims 1 to 6.

Images