Auxiliary chamber type internal combustion engine

Abstract

To provide an auxiliary chamber type internal combustion engine which can easily form even air-fuel mixture.SOLUTION: An auxiliary chamber type internal combustion engine includes a pent-roof type main combustion chamber, a sub-combustion chamber protruding beyond a ridge line of the pent-roof and disposed across a partition wall from the main combustion chamber, a communication passage disposed in the partition wall, and a guide part disposed on the ridge line of the pent-roof and guiding air-fuel mixture toward 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 the mixture is supplied from the main combustion chamber to the pre-chamber, where it is burned. In such passive-type pre-chamber internal combustion engines, the direct-injected fuel injected into the pre-chamber, but which does not enter the pre-chamber and instead passes outside the pre-chamber, forms a rich mixture on the opposite side of the cylinder center from the fuel injection valve. Furthermore, in pre-chamber internal combustion engines that use a pent-roof cylinder head, a rich mixture tends to accumulate near the ridge of the pent-roof (between the intake and exhaust sides).

[0005] An object of the present disclosure is to provide a pre-chamber internal combustion engine that is easy to form a homogeneous air-fuel mixture. [Means for solving the problem]

[0006] The pre-combustion chamber internal combustion engine according to the present disclosure comprises a pent roof-type main combustion chamber, an auxiliary combustion chamber that protrudes across the ridgeline of the pent roof and is arranged with a partition wall between it and the main combustion chamber, a communication passage arranged in the partition wall, and a guide section that is arranged on the ridgeline of the pent roof and guides the air-fuel mixture to the communication passage. [Effects of the Invention]

[0007] With this configuration, the guide portion located on the ridgeline of the pent roof guides the air-fuel mixture toward the communication passage. This prevents a rich air-fuel mixture from accumulating near the ridgeline of the pent roof, and a homogeneous air-fuel mixture is formed in the main combustion chamber. The air-fuel mixture guided to the communication passage is supplied to the auxiliary combustion chamber. [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 section II of Figure 1. [Figure 4] FIG. 2 is a diagram showing a spray state during fuel injection in a pre-combustion chamber type internal combustion engine according to an embodiment of the present disclosure. [Figure 5] 4 is a diagram showing a spray state near a guide portion of a pre-chamber type internal combustion engine according to an embodiment of the present disclosure; FIG. 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 guide portion 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 (see arrow T in FIG. 1) 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, straddling the ridgeline formed at the top of the pent roof shape. The auxiliary combustion chamber 3 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 is disposed adjacent to the main combustion chamber 2, and has a space surrounded by the auxiliary combustion chamber wall 5.

[0013] As shown in FIG. 2, in this embodiment, the communication passage 4 is arranged in the auxiliary combustion chamber wall 5. The communication passage 4 connects the main combustion chamber 2 and the auxiliary combustion chamber 3. As shown in FIG. 3, the communication passage 4 has two first communication passages 4a and multiple second communication passages 4b. The two first communication passages 4a extend in the ridge direction and overlap with the ridge X of the pent roof shape when viewed in the sliding direction P. The multiple second communication passages 4b are oriented in a different direction from the first communication passages 4a. As shown in FIG. 3, in this embodiment, a total of six second communication passages 4b are arranged, three on the intake side and three on the exhaust side.

[0014] As shown in Fig. 1, the guide portion 6 is located upstream of the tumble flow. More specifically, as shown in Fig. 3, the guide portion 6 is disposed on the ridge line X of the pent roof. In this embodiment, the guide portion 6 is disposed on both the front side F and the rear side B of the auxiliary combustion chamber wall 5. The guide portion 6 is disposed in close contact with the side wall of the auxiliary combustion chamber wall 5.

[0015] As shown in FIG. 2, the guide portion 6 protrudes from the cylinder head 12 toward the bottom dead center in the sliding direction P. The guide portion 6 is disposed at a position overlapping with the first communication passage 4a in the sliding direction P and guides the air-fuel mixture to the first communication passage 4a. The guide portion 6 has a curved portion 6a. The curved portion 6a protrudes from the ridge line X toward the bottom dead center in the sliding direction P of the piston 8 and is a portion that curves in an arc from the direction of the fuel injection valve 9 (see FIG. 1 or 3) toward the sliding direction P. The plane obtained by extending the curved portion 6a toward the bottom dead center in the sliding direction P is located on the opposite side of the first communication passage 4a from the fuel injection valve 9. As shown by the imaginary line C1 in FIG. 2, the plane obtained by extending the curved portion 6a toward the bottom dead center in the sliding direction P is a plane tangential to an end portion 6b of the curved portion 6a on the bottom dead center side in the sliding direction P.

[0016] 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 3. 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 approximately center of the auxiliary combustion chamber 3 toward the cylinder 10a.

[0017] As shown in FIG. 1, a piston 8 is housed in a cylinder 10a and slides within the cylinder 10a. The cylinder 10a surrounds the periphery of the main combustion chamber 2. 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.

[0018] As shown in Figure 4, the auxiliary combustion chamber type internal combustion engine 1 configured as above injects fuel using a fuel injection valve 9 to form an air-fuel mixture in the main combustion chamber 2 and the auxiliary combustion chamber 3. At this time, the fuel spray injected from the fuel injection valve 9 (see the dotted hatching in Figure 4) is carried by a tumble flow and hits the guide portion 6.

[0019] As shown in Figure 5, when the fuel spray hits the curved portion 6a of the guide portion 6, the fuel spray diffuses. At this time, the tumble flow also hits the curved portion 6a of the guide portion 6 and changes direction along the curved portion 6a toward the bottom dead center in the sliding direction P. The diffused fuel spray becomes an air-fuel mixture while diffusing along the tumble flow. The air-fuel mixture is guided to the curved portion 6a together with the tumble flow toward the bottom dead center in the sliding direction P along a plane extending from the curved portion 6a toward the bottom dead center in the sliding direction P. In this way, by guiding the air-fuel mixture and the tumble flow using the curved portion 6a of the guide portion 6 arranged in the shape of the ridge line X, it is possible to prevent a rich air-fuel mixture from accumulating near the ridge line.

[0020] The fuel-air mixture guided to the curved portion 6a is guided to the first communication passage 4a, which overlaps with the guide portion 6 in the sliding direction P. At this time, the extended surface of the curved portion 6a is on the opposite side of the fuel injection valve 9 with respect to the first communication passage 4a, so that a fuel-rich mixture is easily supplied to the periphery of the opening of the first communication passage 4a. This makes it easier for a fuel-rich mixture to be supplied to the auxiliary combustion chamber 3. As a result, the combustion energy in the auxiliary combustion chamber 3 increases, and the energy of the jet flame injected from the communication passage 4 increases. When a fuel-rich mixture is supplied to the auxiliary combustion chamber 3, it is possible to prevent the fuel-rich mixture from accumulating in the main combustion chamber 2. As a result, uniform combustion can be achieved in the main combustion chamber 2.

[0021] The air-fuel mixture passes through the communication passage 4 and is supplied to the auxiliary combustion chamber 3. The air-fuel mixture supplied to the auxiliary combustion chamber 3 is ignited by the ignition device 7 to form a flame. The flame in the auxiliary combustion chamber 3 passes through the first communication passage 4a and the second communication passage 4b ​​and is injected into the main combustion chamber 2 as a jet flame.

[0022] As described above, according to the present disclosure, it is possible to provide a pre-chamber internal combustion engine 1 that is likely to form a homogeneous air-fuel mixture.

[0023] 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 arbitrarily combined as necessary. [Explanation of symbols]

[0024] 1: Pre-chamber internal combustion engine, 2: Main combustion chamber, 3: Pre-combustion chamber 4: Connecting passage, 5: Pre-combustion chamber wall 6: Guide section, 6a: Curved section 8: Piston, 9: Fuel injection valve, 10a: Cylinder C1: Virtual line P: sliding direction, X: ridge line

Claims

1. A pent roof type main combustion chamber, an auxiliary combustion chamber that protrudes across the ridgeline of the pent roof and is arranged with a partition wall between it and the main combustion chamber; a communication passage disposed in the partition wall; a guide portion disposed on a ridgeline of the pent roof and configured to guide the air-fuel mixture to the communication passage; Equipped with Pre-chamber internal combustion engine.

2. The communication path is formed in a direction along the ridge line.

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 guide portion protrudes from the ridge line toward the bottom dead center in the piston sliding direction, and has a curved portion on the fuel injection valve side that is curved from the fuel injection valve side toward the sliding direction.

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

4. the communication passage is formed in a direction along the ridge line, a surface of the curved portion extending in the direction of bottom dead center in the sliding direction is located on the opposite side of the communication passage from the fuel injection valve; 4. The pre-combustion chamber type internal combustion engine according to claim 3.

5. The curved portion and the communication passage are disposed at a position where they overlap in the sliding direction.

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

6. A tumble flow is formed in the main combustion chamber, The guide portion is located upstream of the tumble flow.

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

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