Auxiliary chamber type internal combustion engine

Abstract

To provide an auxiliary chamber type internal combustion engine which can suppress unevenness of jet flame.SOLUTION: An auxiliary chamber type internal combustion engine includes a piston sliding within a cylinder, a main combustion chamber, a sub-combustion chamber separated from the main combustion chamber via a partition wall, a communication passage provided in the partition wall and communicating with the main combustion chamber and the sub-combustion chamber, and a diffusion member which diffuses jet flame injected from the communication passage.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, with an ignition device and a fuel injection valve disposed in the pre-combustion chamber. The pre-combustion chamber type internal combustion engine of Patent Document 1 generates an air-fuel mixture in the pre-combustion chamber and ignites this air-fuel mixture 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] Japanese Patent Application Laid-Open No. 2007-85181 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, passive-type pre-chamber internal combustion engines have been developed, in which a fuel injection valve is placed in the main combustion chamber or intake port, and an air-fuel mixture is supplied from the main combustion chamber to the pre-chamber, where the mixture is burned. In such passive-type pre-chamber internal combustion engines, uneven flames are likely to occur due to the richness of the air-fuel mixture near the ignition device. Uneven flames can also cause uneven jet flames injected from the connecting passage. Uneven jet flames can also result in slow combustion near the center of the cylinder. Slow combustion can lead to issues such as longer combustion periods and increased emissions of unburned hydrocarbons.

[0005] An object of the present disclosure is to provide a pre-chamber internal combustion engine that can suppress unevenness in jet flames. [Means for solving the problem]

[0006] The auxiliary combustion chamber type internal combustion engine according to the present disclosure comprises a piston that slides within a cylinder, a main combustion chamber, an auxiliary combustion chamber that is separated from the main combustion chamber by a partition wall, a communication passage provided in the partition wall that connects the main combustion chamber with the auxiliary combustion chamber, and a diffusion member that diffuses a jet flame injected from the communication passage. [Effects of the Invention]

[0007] With this configuration, the jet flame ejected from the communication passage hits the diffusion member and diffuses, thereby suppressing unevenness of the jet flame. As a result, combustion near the cylinder center becomes more uniform, and sluggish combustion near the cylinder center can be prevented. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an internal combustion engine with a pre-chamber according to an embodiment of the present disclosure; [Figure 2] FIG. 2 is an enlarged view of a portion of a pre-combustion chamber according to an embodiment of the present disclosure. [Figure 3] Cross-sectional view II of Figure 2. [Figure 4] 1 is a diagram illustrating fuel spray in a pre-chamber internal combustion engine according to an embodiment of the present disclosure; [Figure 5] FIG. 2 is a diagram showing the fuel spray diffusion state of the pre-chamber internal combustion engine according to the embodiment of the present disclosure. [Figure 6] 1 illustrates a jet flame of a pre-chamber internal combustion engine according to an embodiment of the present disclosure; [Figure 7] FIG. 2 is a diagram showing the diffusion state of a jet flame in a pre-chamber internal combustion engine according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[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, a diffusion member 6, an ignition device 7, 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 or a swirl flow 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. In this embodiment, the auxiliary combustion chamber 3 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. In this embodiment, the auxiliary combustion chamber wall 5 is inclined toward the fuel injection valve 9 on the cylinder head 12 side (top dead center side) in the sliding direction P.

[0013] 2, the auxiliary combustion chamber wall 5 has a bottom wall 51 and a side wall 52. In this embodiment, the side wall 52 is formed in a cylindrical shape. The bottom wall 51 is formed so as to close the piston 8 side of the side wall 52, and has a columnar shape.

[0014] As shown in Fig. 1, the communication passage 4 is provided in the auxiliary combustion chamber wall 5, and connects the main combustion chamber 2 and the auxiliary combustion chamber 3. As shown in Fig. 2, in this embodiment, the communication passage 4 has a first communication passage 4a and a second communication passage 4b. The first communication passage 4a is provided in the bottom wall 51, and connects the main combustion chamber 2 and the auxiliary combustion chamber 3 toward the piston 8. In this embodiment, the first communication passage 4a is provided on the center line of the cylinder 10a, facing the sliding direction P.

[0015] The second communication passage 4b ​​connects the main combustion chamber 2 and the auxiliary combustion chamber 3 toward the cylinder 10a. A plurality of second communication passages 4b are provided. In this embodiment, a total of six second communication passages 4b are provided: three toward the intake side and three toward the exhaust side.

[0016] The jet flame emitted from the communication passage 4 hits the diffusion member 6, which diffuses the jet flame. The diffusion member 6 is held in the auxiliary combustion chamber 3. The diffusion member 6 has a guide portion 6a and multiple holding portions 6b. The guide portion 6a extends toward the fuel injection valve 9 to guide fuel to the first communication passage 4a, and is hit by the jet flame from the first communication passage 4a. The surface of the guide portion 6a facing the first communication passage 4a extends perpendicular to the sliding direction P. The surface of the guide portion 6a facing the piston 8 is formed in a hemispherical shape.

[0017] The plurality of holding portions 6b extend from the auxiliary combustion chamber 3 and hold the guide portion 6a. As shown in Fig. 3, in this embodiment, three holding portions 6b are arranged at 120-degree intervals. At least one of the plurality of holding portions 6b holds an end portion 6c of the guide portion 6a opposite to the side where the fuel injection valve 9 is located. The other holding portions 6b do not hold an end portion 6d of the guide portion 6a on the side where the fuel injection valve 9 is located.

[0018] As shown in FIG. 2, the ignition device 7 is disposed in the auxiliary combustion chamber 3. The ignition device 7 has an ignition coil (not shown) and an ignition plug 7a. A center electrode 7b and a side electrode 7c of the ignition plug 7a protrude into the auxiliary combustion chamber. In this embodiment, the center electrode 7b is disposed approximately in the center of the auxiliary combustion chamber 3. However, the center electrode 7b may be disposed offset from the approximate center of the auxiliary combustion chamber 3 toward the cylinder 10a.

[0019] As shown in FIG. 1, a piston 8 is housed in a cylinder 10a and slides within the cylinder 10a. The piston 8 surrounds the main combustion chamber 2 from below. A fuel injection valve 9 injects fuel toward the main combustion chamber 2 and the auxiliary combustion chamber 3, forming an air-fuel mixture 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. However, the fuel injection valve 9 may also be a port injection type.

[0020] As shown in FIG. 4, the auxiliary combustion chamber type internal combustion engine 1 configured as described above injects fuel using the fuel injection valve 9 to form an air-fuel mixture in the main combustion chamber 2 and the auxiliary combustion chamber 3. More specifically, as shown enlarged in FIG. 4, the fuel injection valve 9 injects fuel toward the guide portion 6a of the diffusion member 6. As shown in FIG. 5, the fuel spray is easily supplied to the guide portion 6a because the retaining portion 6b is not located at the end 6d of the guide portion 6a on the side where the fuel injection valve 9 is located. The fuel spray supplied to the guide portion 6a hits the retaining portion 6b located at the end 6c of the guide portion 6a opposite the side where the fuel injection valve 9 is located and diffuses. As shown in FIG. 4, the diffused fuel spray forms an air-fuel mixture and is supplied to the auxiliary combustion chamber 3 via the first communication passage 4a. This facilitates the supply of a homogeneous air-fuel mixture to the auxiliary combustion chamber 3. The fuel spray around the main combustion chamber 2 side of the auxiliary combustion chamber wall 5 is supplied to the auxiliary combustion chamber 3 via the second communication passage 4b.

[0021] As shown in Fig. 6, when the ignition device 7 ignites the spark plug 7a, first, the air-fuel mixture in the auxiliary combustion chamber 3 is ignited. The flame formed in the auxiliary combustion chamber 3 is jetted out from the first communication passage 4a and the second communication passage 4b ​​as a jet flame.

[0022] As shown enlarged in Figure 6, the jet flame injected from the first communication passage 4a hits the guide portion 6a and diffuses. As shown in Figure 7, the diffused jet flame is ejected toward the main combustion chamber 2 from between the retaining portions 6b. This allows a homogeneous jet flame to be supplied to the main combustion chamber 2 near the center of the cylinder 10a. As a result, it is possible to prevent combustion near the center of the cylinder 10a from becoming sluggish.

[0023] As described above, according to the present disclosure, it is possible to provide a pre-chamber internal combustion engine that can suppress unevenness in the jet flame.

[0024] <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.

[0025] (a) In the above embodiment, the side wall 52 of the auxiliary combustion chamber wall 5 is cylindrical, but the present disclosure is not limited to this. The side wall 52 may have any shape as long as it is a cylindrical member.

[0026] (b) Furthermore, the side wall 52 may be formed integrally with the cylinder head 12 . [Explanation of symbols]

[0027] 1: Pre-chamber internal combustion engine 2: Main combustion chamber, 3: Auxiliary combustion chamber 4: Communication path, 4a: 1st communication path, 4b: 2nd communication path 5: auxiliary combustion chamber wall, 51: bottom wall, 52: side wall 6: Diffusion member, 6a: Guide portion, 6b: Holder portion 6c: The end opposite to the fuel injection valve 6d: End where the fuel injection valve is located 7: Ignition device, 8: Piston, 9: Fuel injection valve 10a: Cylinder, 12: Cylinder head P: Sliding direction

Claims

1. A piston that slides in a cylinder; A main combustion chamber; an auxiliary combustion chamber arranged separated from the main combustion chamber via a partition wall; a communication passage provided in the partition wall and communicating with the main combustion chamber and the auxiliary combustion chamber; a diffusion member that diffuses the jet flame injected from the communication passage; Equipped with Pre-chamber internal combustion engine.

2. The diffusion member is held in the auxiliary combustion chamber.

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

3. Further provided is a fuel injection valve for injecting fuel, the diffusion member extends toward the fuel injection valve, guides the fuel to the communication passage, and has a guide portion on which flames from the communication passage impinge.

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

4. the diffusion member extends from the auxiliary combustion chamber and has a holding portion that holds the guide portion, the holding portion holds an end portion of the guide portion opposite to a side where the fuel injection valve is located.

4. The pre-combustion chamber type internal combustion engine according to claim 3.

5. the partition wall has a bottom wall, and the communication passage is provided in the bottom wall; The guide portion extends in a direction perpendicular to the piston sliding direction.

5. The pre-chamber internal combustion engine according to claim 3 or 4.

Images