Cylinder head cover

Abstract

To prevent stirring of oil and moisture in a flow passage of blow-by gas.SOLUTION: A cylinder head cover 60 is applied to an internal combustion engine 10 using hydrogen as fuel, and includes a head cover body 61A and a lead-out passage 61B. The head cover body 61A defines a main flow passage 62 of blow-by gas leaking to a crankcase 24 from a combustion chamber CC. The lead-out passage 61B is connected to a downstream end 62E of the main flow passage 62, and guides the blow-by gas to an intake passage IP. The main flow passage 62 has a throttle 62C in the halfway of the main flow passage 62. The cylinder head cover 60 further includes an auxiliary flow passage 66. The auxiliary flow passage 66 is connected to an upstream passage 62A in the upstream side of the throttle 62C. The auxiliary flow passage 66 guides the blow-by gas to the lead-out passage 61B or the intake passage IP.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cylinder head cover. [Background technology]

[0002] Patent Document 1 discloses an oil separator that is molded integrally with a cylinder head cover. The oil separator has a gas flow path for blow-by gas. This gas flow path is for guiding the blow-by gas that has leaked from the combustion chamber to the crankcase to the intake passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-200777 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an oil separator such as that described in Patent Document 1, a throttle section with a small cross-sectional area may be present in the middle of the gas flow passage. In such a structure, the flow velocity of the blow-by gas increases downstream of the throttle section in the gas flow passage. In particular, in a hydrogen engine that uses hydrogen as fuel, the blow-by gas contains a relatively large amount of moisture. Therefore, oil and moisture are easily mixed downstream of the throttle section in the gas flow passage, causing emulsion. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention is a cylinder head cover that is applied to an internal combustion engine that uses hydrogen as fuel, and comprises: a head cover body that defines a main flow path for blow-by gas that leaks from the combustion chamber to the crankcase; and an outlet passage that is connected to the downstream end of the main flow path and for guiding the blow-by gas to an intake passage, wherein the main flow path has a throttling portion midway through the main flow path, and when the portion of the main flow path upstream of the throttling portion is defined as an upstream flow path and the portion of the main flow path downstream of the throttling portion is defined as a downstream flow path, the flow path cross-sectional area of ​​the throttling portion is smaller than the flow path cross-sectional area of ​​the upstream flow path and is also smaller than the flow path cross-sectional area of ​​the downstream flow path, and further comprises a secondary flow path that is connected to the upstream flow path and for guiding the blow-by gas to the outlet passage or the intake passage. Effect of the Invention

[0006] This prevents oil and water from being mixed together in the flow path of blow-by gas. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing one embodiment of an internal combustion engine. [Diagram 2] FIG. 2 is a top view of the cover portion of the head cover main body. [Diagram 3] FIG. 3 is a top view of the bottom of the head cover body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <One embodiment of a cylinder head cover> Hereinafter, an embodiment of a cylinder head cover will be described with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. The dimensional ratios of the components may differ from those in the actual product or from those in other drawings.

[0009] (Overall structure) 1, the internal combustion engine 10 includes an oil pan 25, a crankcase 24, a cylinder block 23, a cylinder head 22, and a cylinder head cover 60. The internal combustion engine 10 also includes a plurality of pistons 31, a plurality of connecting rods 32, and a crankshaft 33.

[0010] The oil pan 25 is located at the lower end of the internal combustion engine 10. The oil pan 25 is generally shaped like a rectangular box having a bottom. The oil pan 25 defines an oil space 25A for storing oil. The oil stored in the oil space 25A is supplied to each part of the internal combustion engine 10 by a pump (not shown).

[0011] The crankcase 24 is connected to the upper end of the oil pan 25. The crankcase 24 defines a lower space 24A as a space inside the crankcase 24. The lower space 24A extends from the upper end to the lower end of the crankcase 24. The lower space 24A is connected to the upper end of the oil space 25A.

[0012] The cylinder block 23 defines an upper space 23A and a cylinder 23B as spaces inside the cylinder block 23. The upper space 23A is connected to the upper end of the lower space 24A. The upper space 23A extends from the lower end of the cylinder block 23 to near the center in the up-down direction. The cylinder 23B extends from the upper end of the upper space 23A to the upper end of the cylinder block 23. Note that FIG. 1 shows only one cylinder 23B as a representative. The cylinder block 23 also defines a first blow-by gas passage 23C. The lower end of the first blow-by gas passage 23C is connected to the upper space 23A. The first blow-by gas passage 23C extends to the upper end of the cylinder block 23.

[0013] The piston 31 is located inside the cylinder 23B. The crankshaft 33 is located in the upper space 23A and the lower space 24A. The connecting rod 32 connects the piston 31 to the crankshaft 33. Therefore, when a mixture of fuel and intake air is burned in the cylinder 23B, the piston 31 reciprocates inside the cylinder 23B. Then, the reciprocating motion of the piston 31 is transmitted to the crankshaft 33 as a rotational motion via the connecting rod 32.

[0014] The cylinder head 22 is connected to the upper end of the cylinder block 23. The cylinder head 22 defines a combustion recess 22C, an intake port 22A, and an exhaust port 22B as an internal space of the cylinder head 22. The combustion recess 22C is recessed upward from the lower surface of the cylinder head 22. The combustion recess 22C is connected to the upper end of the cylinder 23B. The combustion recess 22C, the cylinder 23B, and the piston 31 define a combustion chamber CC. The cylinder head 22 also defines a second blow-by gas passage 22D. The lower end of the second blow-by gas passage 22D is connected to the upper end of the first blow-by gas passage 23C. The second blow-by gas passage 22D extends to the upper end of the cylinder head 22.

[0015] A first end of the intake port 22A is connected to the combustion recess 22C. A second end of the intake port 22A opens to a side surface of the cylinder head 22. A first end of the exhaust port 22B is connected to the combustion recess 22C. A second end of the exhaust port 22B opens to a side surface of the cylinder head 22.

[0016] The internal combustion engine 10 includes an intake pipe 41A and an exhaust pipe 41B. The intake pipe 41A is connected to a second end of the intake port 22A. The intake pipe 41A introduces intake air from outside the internal combustion engine 10 into the intake port 22A. The intake port 22A introduces the intake air that has flowed through the intake pipe 41A into the cylinder 23B. In this embodiment, the intake port 22A and the intake pipe 41A form an intake passage IP of the internal combustion engine 10.

[0017] The exhaust pipe 41B is connected to a second end of the exhaust port 22B. The exhaust port 22B discharges exhaust from the cylinder 23B to the exhaust pipe 41B. The exhaust pipe 41B discharges the exhaust that has flowed through the exhaust port 22B to the outside of the internal combustion engine 10. In this embodiment, the exhaust port 22B and the exhaust pipe 41B form an exhaust passage EP of the internal combustion engine 10.

[0018] The cylinder head cover 60 includes a head cover body 61A. The head cover body 61A is connected to the upper end of the cylinder head 22. The head cover body 61A covers the cylinder head 22. The head cover body 61A and the cylinder head 22 define an accommodation space HS. The accommodation space HS accommodates a valve mechanism and the like (not shown). The cylinder head cover 60 will be described in detail later.

[0019] The internal combustion engine 10 includes a plurality of intake valves 42A, a plurality of exhaust valves 42B, a plurality of fuel injectors 43, and a plurality of ignition devices 44. The intake valve 42A is located at the connection between the intake port 22A and the cylinder 23B. The intake valve 42A opens and closes the opening of a first end of the intake port 22A by driving force from a valve mechanism (not shown). The exhaust valve 42B is located at the connection between the exhaust port 22B and the cylinder 23B. The exhaust valve 42B opens and closes the opening of a first end of the exhaust port 22B by driving force from a valve mechanism (not shown).

[0020] A tip of the fuel injection valve 43 is located in the combustion recess 22C. Hydrogen stored in a fuel tank (not shown) is supplied to the fuel injection valve 43. The fuel injection valve 43 injects hydrogen as fuel into the combustion chamber CC. A tip of the ignition device 44 is located in the combustion recess 22C. The ignition device 44 ignites a mixture of fuel and intake air by spark discharge.

[0021] The internal combustion engine 10 is equipped with an air cleaner 45, a turbocharger 46, an intercooler 47, and a throttle valve 48. The turbocharger 46 includes a compressor wheel 46A, a connecting shaft 46B, and a turbine wheel 46C. The compressor wheel 46A is located in the middle of the intake pipe 41A. A first end of the connecting shaft 46B is connected to the compressor wheel 46A. A second end of the connecting shaft 46B is connected to the turbine wheel 46C. The turbine wheel 46C is located in the middle of the exhaust pipe 41B. Therefore, when the turbine wheel 46C rotates due to the flow of exhaust gas in the exhaust pipe 41B, the compressor wheel 46A rotates together with the turbine wheel 46C via the connecting shaft 46B. As a result, the intake air compressed by the compressor wheel 46A is supplied to the downstream side of the compressor wheel 46A in the intake pipe 41A.

[0022] The air cleaner 45 is located in a portion of the intake pipe 41A that is upstream of the compressor wheel 46A. The air cleaner 45 collects foreign matter contained in the intake air flowing through the intake pipe 41A. The intercooler 47 is located in a portion of the intake pipe 41A that is downstream of the compressor wheel 46A. The intercooler 47 cools the intake air compressed by the compressor wheel 46A. The throttle valve 48 is located in a portion of the intake pipe 41A that is downstream of the intercooler 47. The throttle valve 48 adjusts the amount of intake air flowing through the intake pipe 41A.

[0023] The internal combustion engine 10 is equipped with a blow-by gas treatment device 50. The blow-by gas treatment device 50 is a device that returns blow-by gas that has leaked from the combustion chamber CC into the upper space 23A of the cylinder block 23 and the lower space 24A of the crankcase 24 to the intake pipe 41A. The blow-by gas treatment device 50 is equipped with a main separator 51, a suction passage 52, a PCV passage 53, and a PCV valve 54.

[0024] The main separator 51 is located within the accommodation space HS of the cylinder head cover 60. The main separator 51 collects oil contained in the gas flowing through the main separator 51. A first end of a suction passage 52 is connected to the main separator 51. A second end of the suction passage 52 is connected to the upper space 23A of the cylinder block 23. Although not shown, the main separator 51 is connected to the intake pipe 41A via an ejector and a bypass passage.

[0025] A first end of the PCV passage 53 is connected to the main separator 51. A second end of the PCV passage 53 is connected to a portion of the intake pipe 41A that is downstream when viewed from the throttle valve 48. The PCV valve 54 is located midway through the PCV passage 53. The PCV valve 54 opens and closes the flow path of the PCV passage 53.

[0026] (About the structure of the cylinder head cover) As described above, the cylinder head cover 60 includes the head cover body 61A and the outlet passage 61B.

[0027] The head cover body 61A is generally rectangular and generally box-shaped. In the following description, an axis extending along the long side of the head cover body 61A is defined as a first axis X. An axis extending along the short side of the head cover body 61A is defined as a second axis Y. Furthermore, one of the directions along the first axis X is defined as a first positive direction X1, and the direction along the first axis X opposite to the first positive direction X1 is defined as a first negative direction X2. Furthermore, one of the directions along the second axis Y is defined as a second positive direction Y1, and the direction along the second axis Y opposite to the second positive direction Y1 is defined as a second negative direction Y2.

[0028] As shown in FIGS. 2 and 3, the head cover main body 61A includes a cover portion CM and a bottom portion BM. As shown in FIG. 2, the cover portion CM is a substantially rectangular plate-like shape elongated in the direction along the first axis X. The cover portion CM includes a first inner surface I1, a first partition wall CW1, and a discharge hole H1. The first inner surface I1 is a surface facing the cylinder block 23 when the head cover main body 61A is connected to the upper end of the cylinder block 23. The first partition wall CW1 protrudes from the first inner surface I1. The first partition wall CW1, together with the first inner surface I1, defines a first recess D1 that opens in the direction in which the first inner surface I1 faces. When the cover portion CM is viewed from above, the first recess D1 is a substantially L-shaped space. Specifically, the first recess D1 extends from the second negative direction Y2 side to the second positive direction Y1 side with respect to the center of the cover portion CM, and then extends toward the first positive direction X1 side. The discharge hole H1 is a through hole penetrating the cover portion CM. The discharge hole H1 is located near the end of the first recess D1 on the first positive direction X1 side and the second positive direction Y1 side. Note that the plan view refers to the view of the cover portion CM facing the direction in which the apparent area of ​​the cover portion CM is the largest. The same applies to the following plan views.

[0029] As shown in FIG. 3, the bottom BM is a substantially rectangular plate that is long in the direction along the first axis X. When viewed from above, the outer edge of the bottom BM generally coincides with the outer edge of the cover portion CM. The bottom BM includes a second inner surface I2, a second partition wall CW2, and an intake hole H2. When the head cover main body 61A is connected to the upper end of the cylinder block 23, the second inner surface I2 faces away from the cylinder block 23. The second partition wall CW2 protrudes from the second inner surface I2. The second partition wall CW2, together with the second inner surface I2, defines a second recess D2 that opens in the direction in which the second inner surface I2 faces. When the bottom BM is viewed from above, the second recess D2 has generally the same shape as the first recess D1. Specifically, the second recess D2 extends from the second negative direction Y2 side to the second positive direction Y1 side with respect to the center of the bottom BM, and then extends toward the first positive direction X1 side. The suction hole H2 is a through hole that penetrates the bottom BM. The suction hole H2 is located at the end of the second recess D2 on the second negative direction Y2 side.

[0030] The head cover main body 61A is configured by fitting the cover portion CM and the bottom portion BM together so that the first inner surface I1 and the second inner surface I2 face each other. In this fitted state, the outer edge shape of the first recess D1 and the outer edge shape of the second recess D2 are substantially the same. The first recess D1 and the second recess D2 form the main flow passage 62 of the head cover main body 61A. The upstream end 62D of the main flow passage 62 is the intake hole H2 of the bottom portion BM. The upstream end 62D of the main flow passage 62 is connected to the upper end of the second blow-by gas passage 22D in the cylinder head 22. The downstream end 62E of the main flow passage 62 is the discharge hole H1 of the cover portion CM. Details of the main flow passage 62 will be described later.

[0031] As shown in Fig. 1, the outlet passage 61B is a passage for guiding the blow-by gas to the intake passage IP. A first end of the outlet passage 61B is connected to a downstream end 62E of the main passage 62. A second end of the outlet passage 61B is connected to a portion of the intake pipe 41A that is downstream of the air cleaner 45 and upstream of the compressor wheel 46A. Therefore, the blow-by gas leaked from the combustion chamber CC to the crankcase 24 can flow to the intake passage IP through the first blow-by gas passage 23C, the second blow-by gas passage 22D, the main passage 62, and the outlet passage 61B.

[0032] (About the flow path of blow-by gas) As shown in FIG. 2 and FIG. 3, the main flow passage 62 has a throttle section 62C in the middle of the main flow passage. The passage of the main flow passage 62 upstream of the throttle section 62C is defined as an upstream flow passage 62A. The passage of the main flow passage 62 downstream of the throttle section 62C is defined as a downstream flow passage 62B. In this embodiment, the throttle section 62C is the portion of the main flow passage 62 where the flow passage cross-sectional area is the smallest. Therefore, the flow passage cross-sectional area of ​​the throttle section 62C is smaller than that of the upstream flow passage 62A. In addition, the flow passage cross-sectional area of ​​the throttle section 62C is smaller than that of the downstream flow passage 62B. The flow passage cross-sectional area refers to the cross-sectional area of ​​the main flow passage 62 perpendicular to the flow passage direction when the flow passage of the blow-by gas is imagined.

[0033] The upstream flow passage 62A is a portion in the second negative direction Y2 with respect to the throttle portion 62C. A first end of the upstream flow passage 62A coincides with an upstream end 62D of the main flow passage 62. Therefore, in the upstream flow passage 62A, the blow-by gas flows in the second positive direction Y1 as a whole.

[0034] The downstream flow passage 62B is a portion on the second positive direction Y1 side with respect to the throttle portion 62C. A second end of the downstream flow passage 62B coincides with a downstream end 62E of the main flow passage 62. Therefore, in the downstream flow passage 62B, the blow-by gas as a whole flows in the first positive direction X1.

[0035] As shown in FIG. 2, the head cover body 61A includes a rib 63. The rib 63 protrudes from a wall surface that divides the main flow path 62 of the head cover body 61A. More specifically, the rib 63 protrudes from the first inner surface I1 of the cover portion CM in substantially the entire area of ​​the upper flow path 62A and the downstream flow path 62B. When the first inner surface I1 is viewed in a plan view, the rib 63 protrudes in a lattice shape. The dimension in the direction perpendicular to the first inner surface I1 is defined as the height dimension. At this time, the height dimension of the rib 63 in the downstream flow path 62B is lower than the height dimension of the rib 63 in the upstream flow path 62A. Specifically, the minimum value of the height dimension of the rib 63 in the downstream flow path 62B is smaller than the maximum value of the height dimension of the rib 63 in the upstream flow path 62A.

[0036] The cylinder head cover 60 includes a wall portion 64 , a recessed portion 65 , and a secondary flow passage 66 . The wall portion 64 protrudes from the inner surface of the head cover main body 61A. More specifically, the wall portion 64 is composed of a first wall portion PW1 and a second wall portion PW2. As shown in FIG. 2, the first wall portion PW1 protrudes from the first inner surface I1 of the cover portion CM in the upper flow path 62A. When the cover portion CM is viewed in a plan view, the first wall portion PW1 extends approximately along the first axis X. As shown in FIG. 3, the second wall portion PW2 protrudes from the second inner surface I2 of the bottom portion BM in the upper flow path 62A. When the bottom portion BM is viewed in a plan view, the first wall portion PW1 extends approximately along the first axis X. When the cover portion CM and the bottom portion BM are fitted together such that the first inner surface I1 and the second inner surface I2 face each other, the first wall portion PW1 and the second wall portion PW2 are in a state in which their respective tips are butted against each other. Therefore, the first wall portion PW1 and the second wall portion PW2 are one integral wall portion 64 extending from the first inner surface I1 to the second inner surface I2. In addition, as shown in Fig. 3, when the head cover body 61A is viewed in a plan view, the wall portion 64 intersects with an arbitrary line segment L connecting the upstream end 62D of the main flow path 62 and the throttle portion 62C.

[0037] The recessed portion 65 is recessed from the inner surface of the head cover main body 61A toward the outside in the upstream flow path 62A. More specifically, the recessed portion 65 is located on the first inner surface I1 of the cover portion CM downstream of the wall portion 64 on the narrowed portion 62C side. The recessed portion 65 is recessed in the first inner surface I1 of the cover portion CM in the opposite direction to the bottom portion BM.

[0038] The sub-flow passage 66 is a tubular passage for guiding the blow-by gas to the outlet passage 61B or the intake passage IP. As shown in FIG. 1, the sub-flow passage 66 is located outside the head cover main body 61A. A first end of the sub-flow passage 66 is connected to the upper flow passage 62A. More specifically, the first end of the sub-flow passage 66 is connected to the bottom surface of the recessed portion 65. Therefore, the sub-flow passage 66 is connected to the upstream flow passage 62A on the downstream side of the wall portion 64. A second end of the sub-flow passage 66 is connected to the middle of the outlet passage 61B.

[0039] (Operation of this embodiment) In the internal combustion engine 10, blow-by gas leaks from the combustion chamber CC to the crankcase 24. The blow-by gas flows into the main flow passage 62 through the first blow-by gas passage 23C and the second blow-by gas passage 22D. A secondary flow passage 66 is connected to the main flow passage 62 upstream of the throttle section 62C. Therefore, a part of the blow-by gas flows through the secondary flow passage 66. That is, the flow of the blow-by gas branches off upstream of the throttle section 62C in the main flow passage 62.

[0040] (Effects of this embodiment) (1) In the above embodiment, the cylinder head cover 60 includes the sub-passage 66. The sub-passage 66 is connected to the upstream passage 62A of the main passage 62. By directing a part of the blow-by gas in the upstream passage 62A to the sub-passage 66, the flow velocity of the blow-by gas in the downstream passage 62B decreases. Therefore, the oil and water are prevented from being mixed in the downstream passage 62B.

[0041] (2) In the above embodiment, the height dimension of the rib 63 in the downstream flow path 62B is lower than the height dimension of the rib 63 in the upstream flow path 62A. Therefore, turbulence of the blow-by gas is less likely to occur around the rib 63. As a result, even if the blow-by gas flows around the rib 63 in the downstream flow path 62B, emulsion is relatively less likely to occur.

[0042] (3) In the above embodiment, the head cover main body 61A has a wall portion 64 in the upstream flow passage 62A. At least a part of the blow-by gas that flows in from the upstream end 62D of the upstream flow passage 62A collides with this wall portion 64. At this time, oil contained in the blow-by gas adheres to the wall portion 64, making it easy to remove the oil.

[0043] (4) In the above embodiment, the sub-flow passage 66 is located downstream of the wall portion 64. After a portion of the oil contained in the blow-by gas is removed by the wall portion 64, the blow-by gas flows into the sub-flow passage 66. This makes it possible to prevent a large amount of oil from flowing into the sub-flow passage 66.

[0044] (5) In the above embodiment, the sub-flow passage 66 is connected to the recessed portion 65 of the head cover main body 61A. By purposely connecting the sub-flow passage 66 to the recessed portion 65 in this manner, it is relatively difficult for blow-by gas to flow into the sub-flow passage 66. Therefore, it is possible to prevent the amount of blow-by gas flowing through the main flow passage 62 from decreasing due to too much blow-by gas flowing into the sub-flow passage 66.

[0045] <Example of change> The above embodiment and the following modified examples can be implemented in combination with each other to the extent that no technical contradiction occurs.

[0046] The configurations of the head cover main body 61A, the cover portion CM, and the bottom portion BM are not limited to the examples of the above embodiment. For example, the bottom portion BM may not have the second recess portion D2. In this case, the main flow path 62 is formed only by the first recess portion D1 of the head cover main body 61A. In addition, the head cover main body 61A does not have to be composed of two members, the cover portion CM and the bottom portion BM. In other words, the head cover main body 61A may be composed of one integrally molded member, or may be composed of a combination of three or more members.

[0047] The shape, position, size, and other configurations of the discharge hole H1 are not limited to those in the above embodiment. For example, the discharge hole H1 may be a through hole penetrating the cover part CM via the first partition wall CW1. The discharge hole H1 may also be a through hole penetrating the bottom part BM. The same applies to the suction hole H2.

[0048] The main flow path 62 may include a plurality of throttle sections 62C. Even in this case, if the sub-flow path 66 is connected to the upstream flow path 62A upstream of any of the throttle sections 62C, the effect described in (1) can be obtained downstream of the throttle section 62C.

[0049] The shape, size, position, and other configurations of the upstream flow path 62A are not limited to those of the above embodiment. The same is true for the downstream flow path 62B. Even if the configurations of the respective flow paths are different, the effect described in (1) can be obtained as long as the throttle portion 62C and the sub-flow path 66 are provided.

[0050] The shape, size, position, and other configurations of the rib 63 are not limited to those of the above embodiment. For example, the rib 63 may protrude from the first inner surface I1 of the cover portion CM only in the upstream flow path 62A. The height dimension of the rib 63 in the downstream flow path 62B may be equal to or greater than the height dimension of the rib 63 in the upstream flow path 62A. The rib 63 may protrude from the second inner surface I2 of the bottom portion BM. The head cover main body 61A may not include the rib 63. However, it is preferable to provide the rib 63 from the viewpoint of ensuring the strength of the head cover main body 61A.

[0051] The shape, size, position, and other configurations of the recessed portion 65 are not limited to those in the above embodiment. In addition, the head cover main body 61A does not have to have the recessed portion 65. Even if the recessed portion 65 is not present, the effect described in (1) can be obtained by providing the secondary flow path 66.

[0052] The shape, size, position, and other configurations of the wall portion 64 are not limited to those in the above embodiment. For example, the wall portion 64 does not have to be composed of the first wall portion PW1 and the second wall portion PW2, and may be an integrally molded wall portion 64. In addition, the head cover main body 61A does not have to include the wall portion 64.

[0053] The configuration of the sub-flow passage 66 is not limited to the example of the above embodiment. The sub-flow passage 66 is connected to at least the upstream flow passage 62A, and the effect described in (1) can be obtained as long as the sub-flow passage 66 guides the blow-by gas to the outlet passage 61B or the intake passage IP. For example, the sub-flow passage 66 may be connected to the second inner surface I2 of the bottom portion BM in the upstream flow passage 62A. The sub-flow passage 66 may be connected to the upstream side of the wall portion 64 in the upstream flow passage 62A. The first end of the sub-flow passage 66 may be directly connected to the first inner surface I1 instead of the bottom surface of the recessed portion 65. The sub-flow passage 66 may branch midway and be connected to both the outlet passage 61B and the intake passage IP. The head cover main body 61A may also be provided with two or more sub-flow passages 66. [Explanation of symbols]

[0054] 10...internal combustion engine 60...cylinder head cover 61A...head cover body CM...cover portion I1...first inner surface CW1...first partition wall D1...first recess H1...discharge hole BM...bottom portion I2...second inner surface CW2...second partition wall D2...second recess H2...suction hole 61B...outlet passage 62...main flow path 62A...upstream flow path 62B...downstream flow path 62C...throttling portion 62D...upstream end 62E...downstream end 63...rib 64...wall portion PW1...first wall portion PW2...second wall portion 65...recess portion 66...sub-flow path L...line segment

Claims

1. Applied to hydrogen-fueled internal combustion engines, a head cover body defining a main flow path for blow-by gas leaking from the combustion chamber to the crankcase; a guide passage connected to a downstream end of the main flow passage for guiding the blow-by gas to an intake passage, The main flow path has a throttle portion in the middle of the main flow path, when a portion of the main flow path upstream of the throttle portion is defined as an upstream flow path and a portion of the main flow path downstream of the throttle portion is defined as a downstream flow path, a flow path cross-sectional area of ​​the throttle portion is smaller than a flow path cross-sectional area of ​​the upstream flow path and is also smaller than a flow path cross-sectional area of ​​the downstream flow path, The blow-by gas passage is connected to the upstream passage and further includes a sub-passage for directing the blow-by gas to the outlet passage or the intake passage. Cylinder head cover.

2. The head cover body includes a rib protruding from a wall surface that defines the main flow path, When the dimension perpendicular to the wall surface is the height dimension, The height dimension of the ribs in the downstream flow path is lower than the height dimension of the ribs in the upstream flow path.

2. The cylinder head cover according to claim 1.

3. The upstream flow path further includes a wall portion protruding from an inner surface of the head cover body, The wall portion intersects with any line segment connecting the upstream end of the main flow path and the throttle portion.

2. The cylinder head cover according to claim 1.

4. The sub-flow passage is connected to the upstream flow passage downstream of the wall portion.

4. A cylinder head cover according to claim 3.

5. The head cover body includes a recessed portion recessed from an inner surface of the upstream flow path toward an outer side of the main flow path, The secondary flow passage is connected to the recessed portion.

2. The cylinder head cover according to claim 1.

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