Auxiliary chamber type internal combustion engine

Abstract

To provide an auxiliary chamber type internal combustion engine which can form air-fuel mixture having a high fuel concentration around a sub-combustion chamber in a main combustion chamber in which a vortex flow is formed.SOLUTION: An auxiliary chamber type internal combustion engine includes a main combustion chamber in which a vortex flow is formed, a sub-combustion chamber disposed across a partition wall from the main combustion chamber, and a fuel injection valve which injects fuel into the main combustion chamber. The fuel injection valve has a first injection injected toward the vortex flow, and a second injection injected toward the sub-combustion chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a pre-chamber internal combustion engine. [Background technology]

[0002] Conventionally, a pre-combustion chamber type internal combustion engine has been known (see, for example, Patent Document 1). The pre-combustion chamber type internal combustion engine of Patent Document 1 comprises a main combustion chamber and a pre-combustion chamber, an ignition device disposed in the pre-combustion chamber, and a fuel injection valve disposed in the main combustion chamber. The pre-combustion chamber type internal combustion engine of Patent Document 1 is a passive type pre-combustion chamber type internal combustion engine that forms an air-fuel mixture in the pre-combustion chamber by supplying fuel injected from the main combustion chamber to the pre-combustion chamber. The air-fuel mixture formed in the pre-combustion chamber is ignited by an ignition device to form a flame. The flame formed in the pre-combustion chamber is injected into the main combustion chamber via a communication passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 7255673 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a passive type pre-combustion chamber internal combustion engine, it is preferable to form a fuel-rich mixture around the pre-combustion chamber and supply the mixture to the pre-combustion chamber. In the pre-combustion chamber internal combustion engine of Patent Document 1, fuel is sprayed from the fuel injection valve to the outside of the pre-combustion chamber, forming a fuel-rich mixture around the pre-combustion chamber. Patent Document 1 does not disclose how fuel injection should be performed when a vortex is formed in the main combustion chamber.

[0005] An object of the present disclosure is to provide an internal combustion engine with a pre-combustion chamber that can form a fuel-rich mixture around the pre-combustion chamber in the main combustion chamber where a vortex is formed. [Means for solving the problem]

[0006] The auxiliary combustion chamber type internal combustion engine according to the present disclosure comprises a main combustion chamber in which a vortex is formed, an auxiliary combustion chamber arranged with respect to the main combustion chamber via a partition wall, and a fuel injection valve that injects fuel into the main combustion chamber, the fuel injection valve having a first injection that is injected into the vortex and a second injection that is injected toward the auxiliary combustion chamber. [Effects of the Invention]

[0007] In this pre-combustion chamber internal combustion engine, the first injection forms a mixture around the main combustion chamber and the pre-combustion chamber, which is diffused by a swirl flow. The second injection is directed toward the pre-combustion chamber, supplying a fuel spray around the pre-combustion chamber. The pre-combustion chamber internal combustion engine forms a fuel-rich mixture around the pre-combustion chamber through the first and second injections. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side cross-sectional view of the vicinity of a communication passage, illustrating an injection pattern of an internal combustion engine with a pre-combustion chamber according to an embodiment of the present disclosure; [Figure 2] FIG. 2 is a bottom cross-sectional view of the vicinity of a communication passage, illustrating the injection pattern of the pre-chamber type internal combustion engine according to the embodiment of the present disclosure. [Figure 3] 1 is a diagram illustrating a nozzle hole of a fuel injection valve according to an embodiment of the present disclosure; [Figure 4] 2 is a diagram illustrating a fuel supply passage of a fuel injection valve according to an embodiment of the present disclosure; [Figure 5] FIG. 10 is a bottom cross-sectional view of the vicinity of a communication passage, illustrating an injection pattern of an internal combustion engine with a pre-combustion chamber according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the sliding direction of piston 8 is indicated as P, the side where intake valve 14 is located is indicated as intake side IN, the side where exhaust valve 16 is located is indicated as exhaust side EX, and the direction in which ridge line X1 extends is indicated as ridge line direction X.

[0010] As shown in FIG. 1, the auxiliary combustion chamber type internal combustion engine 1 includes a main combustion chamber 2, an auxiliary combustion chamber 3, a communication passage 4, an ignition device 6, a piston 8, and a fuel injection valve 9.

[0011] The main combustion chamber 2 is a space surrounded by the cylinder 10a of the cylinder block 10, the cylinder head 12, and the piston 8. In this embodiment, the main combustion chamber 2 has a pent roof shape, with two slopes formed toward the intake port 12a side and the exhaust port 12b side of the cylinder head 12. The main combustion chamber 2 is connected to the intake port 12a via an intake valve 14. The intake port 12a is connected, for example, to an intake passage (not shown). The intake port 12a in this embodiment forms a tumble flow T in the main combustion chamber 2. The main combustion chamber 2 is connected to the exhaust port 12b via an exhaust valve 16. The exhaust port 12b is connected, for example, to an exhaust passage (not shown).

[0012] The auxiliary combustion chamber 3 protrudes from the cylinder head 12 toward the main combustion chamber 2 and is separated from the main combustion chamber 2 by an auxiliary combustion chamber wall (an example of a partition wall) 5. The auxiliary combustion chamber 3 of this embodiment is located adjacent to the main combustion chamber 2 at the top of the pent roof shape, and has a space surrounded by the auxiliary combustion chamber wall 5. The center line C2 of the auxiliary combustion chamber 3 of this embodiment coincides with the center line C1 of the main combustion chamber 2.

[0013] The auxiliary combustion chamber wall 5 has a side wall 51 and a bottom wall 52. In this embodiment, the side wall 51 is formed in a cylindrical shape, and the bottom wall 52 is formed in a hemispherical shape.

[0014] The communication passages 4 are provided in the auxiliary combustion chamber wall 5. As shown in Fig. 2, the communication passages 4 communicate between the main combustion chamber 2 and the auxiliary combustion chamber 3. In this embodiment, a total of eight communication passages 4 are provided: two in the direction of the ridge line X1 of the pent roof, three toward the intake side, and three toward the exhaust side.

[0015] As shown in Fig. 1, the ignition device 6 is disposed in the auxiliary combustion chamber 3. The ignition device 6 ignites the air-fuel mixture in the auxiliary combustion chamber 3 by discharging the current flowing through the ignition coil using the central electrode and the side electrode.

[0016] The piston 8 is housed in the cylinder 10a and slides within the cylinder 10a. The piston 8 surrounds the main combustion chamber 2 from below.

[0017] The fuel injection valve 9 injects fuel toward the main combustion chamber 2 and the auxiliary combustion chamber 3, forming a mixture of air and fuel in the main combustion chamber 2 and the auxiliary combustion chamber 3. In this embodiment, the fuel injection valve 9 is a direct injection type that injects fuel directly into the main combustion chamber 2.

[0018] 3, the fuel injection valve 9 has a first nozzle hole 9a and a second nozzle hole 9b. The first nozzle hole 9a injects a first injection F1 toward the center of the vortex (tumble flow T in this embodiment). The second nozzle hole 9b injects a second injection F2 toward the auxiliary combustion chamber 3.

[0019] The number of first nozzle holes 9a is smaller than the number of second nozzle holes 9b. In this embodiment, one first nozzle hole 9a and four second nozzle holes 9b are provided. The first nozzle hole 9a is disposed at a position biased toward the bottom dead center side (toward the piston 8) in the sliding direction P from the center of the ridge line direction X. The four second nozzle holes 9b are disposed closer to the top dead center side (toward the cylinder head 12) in the sliding direction P than the first nozzle hole 9a. The four second nozzle holes 9b are disposed two by two on each side, with the center line C3 of the ridge line direction X of the fuel injection valve 9 as the boundary. As shown in FIG. 2 , the first nozzle hole 9a injects one first injection F1. The four second nozzle holes 9b inject one second injection F2. The first nozzle hole 9a and the second nozzle holes 9b may be disposed in any arrangement as long as the first injection F1 and the second injection F2 do not interfere with each other.

[0020] As shown in FIG. 3, the diameter D1 of the first nozzle hole 9a is equal to or larger than the diameter D2 of the second nozzle hole 9b. In this embodiment, the diameter D1 of the first nozzle hole 9a is larger than the diameter D2 of the second nozzle hole 9b. This makes the penetration force of the second jet F2 stronger than that of the first jet F1. As shown in FIG. 2, the injection angle β of the second jet F2 is smaller than the injection angle α of the first jet F1. In other words, the second jet F2 is thinner and flies farther than the first jet F1. This causes the second jet F2 to collide more strongly with the auxiliary combustion chamber wall 5 and diffuse. This makes it easier to form a fuel-rich mixture around the auxiliary combustion chamber wall 5.

[0021] The injection timing of the first injection F1 is later than the injection timing of the second injection F2. As shown in FIG. 4 , the fuel injection valve 9 of this embodiment has a cylindrical main fuel supply passage 20, a first fuel supply passage 21, a second fuel supply passage 22, and a plunger 23. The main fuel supply passage 20 is supplied with fuel from a fuel tank (not shown). The first fuel supply passage 21 supplies fuel to the first nozzle hole 9a. The second fuel supply passage 22 supplies fuel to the second nozzle hole 9b. Although not shown, in this embodiment, there are four second fuel supply passages 22. The plunger 23 slides within the main fuel supply passage 20 to push fuel into the first fuel supply passage 21 and the second fuel supply passage 22. Since the plunger reaches the second fuel supply passage 22 before the first fuel supply passage 21, fuel flows into the second fuel supply passage 22 before the first fuel supply passage 21. As a result, fuel is injected from the second injection port 9b earlier than from the first injection port 9a. In this way, the injection timing of the first injection F1 is later than the injection timing of the second injection F2.

[0022] In the auxiliary combustion chamber type internal combustion engine 1 configured as described above, the first injection F1 is injected into the tumble flow T. More specifically, the tumble flow T flows on the intake side IN toward the cylinder head 12 in the sliding direction P. The fuel injection valve 9 injects the first injection F1 toward the bottom dead center side (toward the piston 8) of the auxiliary combustion chamber wall 5 in the sliding direction P of the piston 8. The direction toward the tumble flow T is a direction in which the injection axis of the first injection F1 is within a range of approximately ±60 degrees with respect to a direction perpendicular to the tangent of the tumble flow T. The same applies to the swirl flow S described below. As a result, the first injection F1 crosses the tumble flow T and is diffused. The first injection F1 diffused by the tumble flow T flows toward the top dead center side (toward the cylinder head 12) in the sliding direction P on the intake side IN and flows around the auxiliary combustion chamber wall 5. As a result, a mixture with a high fuel concentration is formed on the intake side IN of the auxiliary combustion chamber wall 5. A portion of the first injection F1 is carried by the tumble flow T and spreads throughout the main combustion chamber 2, forming an air-fuel mixture in the main combustion chamber 2.

[0023] The second injection F2 injects fuel toward the auxiliary combustion chamber wall 5. The second injection F2 collides with the auxiliary combustion chamber wall 5 and the spray diffuses. This causes a fuel-rich mixture to diffuse toward the intake side IN of the auxiliary combustion chamber wall 5. Meanwhile, part of the diffused second injection F2 flows toward the exhaust side EX of the auxiliary combustion chamber wall 5, forming a fuel-rich mixture all around the auxiliary combustion chamber wall 5.

[0024] In this embodiment, the first injection F1 is injected later than the second injection F2, so that the fuel concentration of the mixture around the auxiliary combustion chamber wall 5 formed by the second injection F2 can be further enriched by the first injection F1.

[0025] The air-fuel mixture formed around the auxiliary combustion chamber wall 5 flows into the auxiliary combustion chamber 3 through the communication passage 4. The air-fuel mixture that flows into the auxiliary combustion chamber 3 is ignited by the ignition device 6. The ignited air-fuel mixture becomes a flame. The flame passes through the communication passage 4 and is injected into the main combustion chamber 2 as a jet flame.

[0026] As described above, according to the present disclosure, it is possible to provide an auxiliary combustion chamber type internal combustion engine 1 that can form a fuel-rich mixture around the auxiliary combustion chamber 3 in the main combustion chamber 2 where a vortex is formed.

[0027] <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 are possible within the scope of the gist of the invention. In particular, the multiple modifications described in this specification can be combined as needed.

[0028] (a) In the above embodiment, an example has been described in which there is one first injection port 9a and four second injection ports 9b, but the present disclosure is not limited to this. It is sufficient for the pre-chamber internal combustion engine 1 to have fewer injection ports for injecting the first injection F1 than the number of injection ports for injecting the second injection F2.

[0029] (b) In the above embodiment, an example has been described in which the vortex formed in the main combustion chamber 2 is a tumble flow T, but the present disclosure is not limited to this. As shown in FIG. 5 , the vortex may be a swirl flow S. More specifically, the pre-combustion chamber internal combustion engine 1 may form a swirl flow S that flows along the cylinder 10a in the main combustion chamber 2 of the pre-combustion chamber internal combustion engine 1. The first injection F1 may be injected into the swirl flow S. As a result, the first injection F1 is diffused by the swirl flow S. A portion of the first injection F1 is carried by the swirl flow S to form an air-fuel mixture around the cylinder 10a. Meanwhile, another portion of the first injection F1 is diffused by the swirl flow S and supplied to the periphery of the pre-combustion chamber wall 5. As a result, the pre-combustion chamber internal combustion engine 1 can form a fuel-rich mixture around the periphery of the pre-combustion chamber wall 5. [Explanation of symbols]

[0030] 1: Pre-chamber internal combustion engine 2: Main combustion chamber 3: Auxiliary combustion chamber 4:Communication path 5: Pre-combustion chamber wall 6:Ignition device 8: Piston 9: fuel injection valve, 9a: first nozzle, 9b: second nozzle F1: 1st injection, F2: 2nd injection

Claims

1. a main combustion chamber in which a vortex is formed; an auxiliary combustion chamber disposed between the main combustion chamber and the auxiliary combustion chamber via a partition wall; a fuel injection valve that injects fuel into the main combustion chamber; Equipped with The fuel injection valve A first jet injected into the vortex; a second injection directed toward the auxiliary combustion chamber; having Pre-chamber internal combustion engine.

2. The penetration force of the second jet is greater than the penetration force of the first jet.

2. The pre-combustion chamber type internal combustion engine according to claim 1.

3. The injection angle of the first injection is greater than the injection angle of the second injection.

2. The pre-chamber internal combustion engine according to claim 1.

4. the number of nozzles for injecting the first jet is less than the number of nozzles for injecting the second jet; 2. The pre-combustion chamber type internal combustion engine according to claim 1.

5. The first injection has a later injection timing than the second injection.

2. The pre-combustion chamber type internal combustion engine according to claim 1.

6. A first nozzle hole for injecting the first fuel injection and a second nozzle hole for injecting the second fuel injection are formed in one fuel injection valve.

6. The pre-chamber internal combustion engine according to claim 1.

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