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 Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an oil separator such as that of Patent Document 1, there may be a throttle portion with a small flow path cross-sectional area in the middle of the gas flow path. In such a structure, the flow velocity of the blow-by gas becomes faster on the downstream side of the throttle portion in the gas flow path. And especially in a hydrogen engine using hydrogen as fuel, the blow-by gas contains a relatively large amount of moisture. Therefore, oil and moisture are easily agitated on the downstream side of the throttle portion in the gas flow path, and an emulsion is likely to occur.

Means for Solving the Problems

[0005] To solve the above problems, the present invention relates to a cylinder head cover applicable to an internal combustion engine using hydrogen as fuel, comprising: a head cover body that partitions the main passage for blow-by gas leaking from the combustion chamber to the crankcase; and an outlet passage connected to the downstream end of the main passage for guiding the blow-by gas to the intake passage, wherein the main passage has a throttling section in the middle of the main passage, and when the part of the main passage upstream of the throttling section is designated as the upper passage, and the part of the main passage downstream of the throttling section is designated as the lower passage, the cross-sectional area of ​​the passage of the throttling section is smaller than the cross-sectional area of ​​the passage of the upper passage and smaller than the cross-sectional area of ​​the passage of the lower passage, and further comprises a sub-passage connected to the upper passage for guiding the blow-by gas to the outlet passage or the intake passage. [Effects of the Invention]

[0006] This prevents oil and water from being mixed in the blow-by gas passage. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing one embodiment of an internal combustion engine. [Figure 2] Figure 2 is a top view of the cover portion of the head cover body. [Figure 3] Figure 3 is a top view of the bottom of the head cover body. [Modes for carrying out the invention]

[0008] <An embodiment of a cylinder head cover> An embodiment of the cylinder head cover will be described below with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. Dimensional ratios of components may differ from those in the actual drawings or those shown in other drawings.

[0009] (Regarding the overall structure) As shown in Figure 1, the internal combustion engine 10 comprises 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 comprises 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 has a roughly rectangular box shape with 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 various parts 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 an internal space of 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 divides the internal space into an upper space 23A and a cylinder 23B. 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 vertical direction. Cylinder 23B extends from the upper end of the upper space 23A to the upper end of the cylinder block 23. Note that in Figure 1, only one cylinder 23B is shown as a representative example. The cylinder block 23 also divides the 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 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 and the crankshaft 33. Therefore, when the fuel-intake mixture burns in cylinder 23B, the piston 31 reciprocates inside cylinder 23B. This reciprocating motion of the piston 31 is then transmitted to the crankshaft 33 as 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 the combustion recess 22C, the intake port 22A, and the exhaust port 22B as internal spaces within 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 the combustion chamber CC. The cylinder head 22 also defines the 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] The first end of the intake port 22A is connected to the combustion recess 22C. The second end of the intake port 22A opens to the side of the cylinder head 22. The first end of the exhaust port 22B is also connected to the combustion recess 22C. The second end of the exhaust port 22B opens to the side of the cylinder head 22.

[0016] The internal combustion engine 10 is equipped with an intake pipe 41A and an exhaust pipe 41B. The intake pipe 41A is connected to the 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 then 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 constitute the intake passage IP of the internal combustion engine 10.

[0017] The exhaust pipe 41B is connected to the second end of the exhaust port 22B. The exhaust port 22B discharges the 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 the present embodiment, the exhaust port 22B and the exhaust pipe 41B are the exhaust passage EP of the internal combustion engine 10.

[0018] The cylinder head cover 60 includes a head cover main body 61A. The head cover main body 61A is connected to the upper end of the cylinder head 22. The head cover main body 61A covers the cylinder head 22. Further, the head cover main body 61A partitions the accommodation space HS together with the cylinder head 22. The accommodation space HS houses a valve operating mechanism and the like (not shown). Details of the cylinder head cover 60 will be described later.

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

[0020] The 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. The tip of the ignition device 44 is located in the combustion recess 22C. The ignition device 44 ignites the mixture of fuel and intake air by spark discharge.

[0021] The internal combustion engine 10 includes 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. The first end of the connecting shaft 46B is connected to the compressor wheel 46A. The 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 the exhaust in the exhaust pipe 41B, the compressor wheel 46A rotates together 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 the upstream portion of the intake pipe 41A with respect to the compressor wheel 46A. The air cleaner 45 collects foreign substances contained in the intake air flowing through the intake pipe 41A. The intercooler 47 is located in the downstream portion of the intake pipe 41A with respect to the compressor wheel 46A. The intercooler 47 cools the intake air compressed by the compressor wheel 46A. The throttle valve 48 is located in the downstream portion of the intake pipe 41A with respect to 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 includes a blow-by gas treatment device 50. The blow-by gas treatment device 50 is a device that returns the blow-by gas 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 includes 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 housing space HS of the cylinder head cover 60. The main separator 51 collects oil contained in the gas flowing through it. The first end of the suction passage 52 is connected to the main separator 51. The second end of the suction passage 52 is connected to the upper space 23A of the cylinder block 23. Although not shown in the figures, the main separator 51 is also connected to the intake pipe 41A via an ejector and a bypass passage.

[0025] The first end of the PCV passage 53 is connected to the main separator 51. The second end of the PCV passage 53 is connected to the portion of the intake pipe 41A downstream of the throttle valve 48. The PCV valve 54 is located in the middle of the PCV passage 53. The PCV valve 54 opens and closes the flow path of the PCV passage 53.

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

[0027] The head cover body 61A is roughly rectangular in shape, roughly like a box. In the following, the axis extending along the long side of the head cover body 61A will be referred to as the first axis X. The axis extending along the short side of the head cover body 61A will be referred to as the second axis Y. Furthermore, one direction along the first axis X will be referred to as the first positive direction X1, and the direction along the first axis X opposite to the first positive direction X1 will be referred to as the first negative direction X2. Similarly, one direction along the second axis Y will be referred to as the second positive direction Y1, and the direction along the second axis Y opposite to the second positive direction Y1 will be referred to as the second negative direction Y2.

[0028] As shown in Figures 2 and 3, the head cover body 61A comprises a cover portion CM and a bottom portion BM. As shown in Figure 2, the cover portion CM is a roughly rectangular plate that is elongated in the direction along the first axis X. The cover portion CM comprises a first inner surface I1, a first partition wall CW1, and a discharge hole H1. The first inner surface I1 is the surface facing the cylinder block 23 when the head cover 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. Together with the first inner surface I1, the first partition wall CW1 partitions a first recess D1 that opens in the direction facing the first inner surface I1. When the cover portion CM is viewed from above, the first recess D1 is generally an 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 that penetrates 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 a plan view refers to viewing the cover portion CM in the direction that maximizes its apparent area. The same applies to the following plan views.

[0029] As shown in Figure 3, the bottom BM is a roughly rectangular plate that is elongated in the direction along the first axis X. When viewed from above, the outer edge of the bottom BM roughly coincides with the outer edge of the cover CM. The bottom BM comprises a second inner surface I2, a second compartment wall CW2, and an intake hole H2. The second inner surface I2 is the surface that faces away from the cylinder block 23 when the head cover body 61A is connected to the upper end of the cylinder block 23. The second compartment wall CW2 protrudes from the second inner surface I2. The second compartment wall CW2, together with the second inner surface I2, defines a second recess D2 that opens in the direction that the second inner surface I2 faces. When the bottom BM is viewed from above, the second recess D2 is roughly 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 intake hole H2 is a through hole that penetrates the bottom BM. The intake hole H2 is located at the end of the second recess D2 on the second negative direction Y2 side.

[0030] The head cover body 61A is constructed by fitting the cover portion CM and the bottom portion BM together such 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 approximately the same. The first recess D1 and the second recess D2 constitute the main passage 62 of the head cover body 61A. The upstream end 62D of the main passage 62 is the intake hole H2 of the bottom portion BM. The upstream end 62D of the main 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 passage 62 is the discharge hole H1 of the cover portion CM. Details of the main passage 62 will be described later.

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

[0032] (Regarding the flow path of blow-by gas) As shown in Figures 2 and 3, the main flow path 62 has a constricted section 62C in the middle of the main flow path. The passage upstream of the constricted section 62C in the main flow path 62 is designated as the upper flow path 62A. The passage downstream of the constricted section 62C in the main flow path 62 is designated as the lower flow path 62B. In this embodiment, the constricted section 62C is the point in the main flow path 62 where the flow path cross-sectional area is smallest. Therefore, the flow path cross-sectional area of ​​the constricted section 62C is smaller than the flow path cross-sectional area of ​​the upper flow path 62A. Also, the flow path cross-sectional area of ​​the constricted section 62C is smaller than the flow path cross-sectional area of ​​the lower flow path 62B. Note that the flow path cross-sectional area refers to the cross-sectional area of ​​the main flow path 62 perpendicular to the flow path direction when the flow path of blow-by gas is imagined.

[0033] The upper flow path 62A is the portion in the second negative direction Y2 relative to the throttling section 62C. The first end of the upper flow path 62A coincides with the upstream end 62D of the main flow path 62. Therefore, within the upper flow path 62A, the blow-by gas flows as a whole in the second positive direction Y1.

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

[0035] As shown in Figure 2, the head cover body 61A is equipped with ribs 63. The ribs 63 protrude from the wall surface that demarcates the main flow path 62 within the head cover body 61A. More specifically, the ribs 63 protrude from the first inner surface I1 of the cover portion CM over substantially the entire area of ​​the upper flow path 62A and the lower flow path 62B. When the first inner surface I1 is viewed from above, the ribs 63 protrude in a grid pattern. The dimension in the direction perpendicular to the first inner surface I1 is defined as the height dimension. In this case, the height dimension of the ribs 63 in the lower flow path 62B is lower than the height dimension of the ribs 63 in the upper flow path 62A. Specifically, the minimum value of the height dimension of the ribs 63 in the lower flow path 62B is smaller than the maximum value of the height dimension of the ribs 63 in the upper flow path 62A.

[0036] The cylinder head cover 60 includes a wall portion 64, a recessed portion 65, and a sub-flow channel 66. The wall portion 64 protrudes from the inner surface of the head cover 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 Figure 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 from above, the first wall portion PW1 extends generally along the first axis X. As shown in Figure 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 from above, the first wall portion PW1 extends generally along the first axis X. When the cover portion CM and the bottom portion BM are fitted together so 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 where their respective ends are abutting against each other. Therefore, the first wall portion PW1 and the second wall portion PW2 form a single integrated wall portion 64 that extends from the first inner surface I1 to the second inner surface I2. Also, as shown in Figure 3, when the head cover body 61A is viewed from above, the wall portion 64 intersects with an arbitrary line segment L connecting the upstream end 62D of the main flow path 62 and the throttling portion 62C.

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

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

[0039] (Regarding the operation of this embodiment) In the internal combustion engine 10, blow-by gas leaks from the combustion chamber CC into the crankcase 24. The blow-by gas flows through the first blow-by gas passage 23C and the second blow-by gas passage 22D into the main passage 62. Upstream of the throttling section 62C of the main passage 62, a sub-passage 66 is connected. Therefore, a portion of the blow-by gas flows through the sub-passage 66. In other words, the flow of blow-by gas branches off upstream of the throttling section 62C in the main passage 62.

[0040] (Regarding the effects of this embodiment) (1) In the above embodiment, the cylinder head cover 60 is provided with a sub-flow channel 66. The sub-flow channel 66 is connected to the upper flow channel 62A of the main flow channel 62. By directing a portion of the blow-by gas in the upper flow channel 62A to the sub-flow channel 66, the flow velocity of the blow-by gas in the lower flow channel 62B is reduced. Therefore, mixing of oil and water in the lower flow channel 62B can be prevented.

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

[0042] (3) In the above embodiment, the head cover body 61A is provided with a wall portion 64 in the upper passage 62A. At least a portion of the blow-by gas flowing in from the upstream end 62D of the upper passage 62A collides with this wall portion 64. At this time, the 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, there is a sub-channel 66 downstream of the wall 64. After some of the oil contained in the blow-by gas is removed by the wall 64, the blow-by gas flows into the sub-channel 66. This prevents a large amount of oil from flowing into the sub-channel 66.

[0044] (5) In the above embodiment, the sub-channel 66 is connected to the recessed portion 65 of the head cover body 61A. By deliberately connecting the sub-channel 66 to the recessed portion 65 in this way, blow-by gas is less likely to flow into the sub-channel 66. Therefore, it is possible to prevent blow-by gas from flowing too much into the sub-channel 66 and reducing the amount of blow-by gas circulating in the main channel 62.

[0045] <Example of changes> The above embodiments and the following modifications can be combined and implemented to the extent that they do not conflict with each other technically.

[0046] The configuration of the head cover body 61A, the cover portion CM, and the bottom portion BM is not limited to the examples of the above embodiment. For example, the bottom portion BM does not have to have the second recess D2. In this case, the main flow path 62 is formed only by the first recess D1 of the head cover body 61A. Also, the head cover body 61A does not have to be composed of two members, the cover portion CM and the bottom portion BM. That is, the head cover body 61A may be composed of one integrally molded member, or it 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 the examples of the above embodiment. For example, the discharge hole H1 may be a through-hole that penetrates the cover portion CM through the first compartment wall CW1. Alternatively, the discharge hole H1 may be a through-hole that penetrates the bottom portion BM. The same applies to the intake hole H2.

[0048] The main flow path 62 may have multiple aperture sections 62C. In this case as well, if the sub-flow path 66 is connected to the upper flow path 62A upstream of any of the aperture sections 62C, the effect described in (1) can be obtained downstream of the aperture section 62C.

[0049] The shape, size, position, and other configurations of the upper channel 62A are not limited to the examples of the above embodiment. The same applies to the lower channel 62B. Even if the configuration of each channel is different, the effects described in (1) can be obtained as long as the throttling section 62C and the sub-channel 66 are provided.

[0050] The shape, size, position, and other configurations of the rib 63 are not limited to the examples 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 upper flow path 62A. Also, the height dimension of the rib 63 in the lower flow path 62B may be greater than or equal to the height dimension of the rib 63 in the upper flow path 62A. The rib 63 may protrude from the second inner surface I2 of the bottom portion BM. Furthermore, the head cover body 61A does not need to be equipped with the rib 63. However, from the viewpoint of ensuring the strength of the head cover body 61A, it is preferable to provide the rib 63.

[0051] The shape, size, position, and other configurations of the recessed portion 65 are not limited to the examples of the above embodiment. Furthermore, the head cover body 61A does not need to have the recessed portion 65. Even without the recessed portion 65, the effects described in (1) can be obtained by providing the sub-flow channel 66.

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

[0053] The configuration of the sub-channel 66 is not limited to the examples of the above embodiment. The effects described in (1) can be obtained if the sub-channel 66 is connected to at least the upper channel 62A and the blow-by gas is guided to the outlet 61B or the intake passage IP. For example, the sub-channel 66 may be connected to the second inner surface I2 of the bottom BM in the upper channel 62A. The sub-channel 66 may be connected upstream of the wall 64 in the upper channel 62A. The first end of the sub-channel 66 may be connected directly to the first inner surface I1, rather than to the bottom surface of the recess 65. The sub-channel 66 may branch midway and be connected to both the outlet 61B and the intake passage IP. In addition, the head cover body 61A may have two or more sub-channels 66. [Explanation of symbols]

[0054] 10…Internal combustion engine 60…Cylinder head cover 61A…Head cover body CM…Cover section I1…First inner surface CW1…First compartment wall D1…First recess H1…Discharge hole BM…Bottom I2…Second inner surface CW2…Second compartment wall D2…Second recess H2…Intake hole 61B…Outlet passage 62…Main passage 62A…Upper passage 62B…Lower passage 62C…Restriction section 62D…Upstream end 62E…Downstream end 63…Rib 64…Wall section PW1…First wall section PW2…Second wall section 65…Recess 66…Sub-passage L…Line segment

Claims

1. Applied to internal combustion engines that use hydrogen as fuel, The head cover body partitions the main passage for blow-by gas leaking from the combustion chamber into the crankcase, It is connected to the downstream end of the main passage and includes an outlet passage for guiding the blow-by gas to the intake passage, The main flow path has a constricted section in the middle of the main flow path, When the main flow channel upstream of the constricted section is designated as the upper flow channel, and the main flow channel downstream of the constricted section is designated as the lower flow channel, the cross-sectional area of ​​the constricted section is smaller than the cross-sectional area of ​​the upper flow channel and smaller than the cross-sectional area of ​​the lower flow channel. It is connected to the upper passage and further includes a sub-pass passage for guiding the blow-by gas to the outlet passage or the intake passage, The head cover body comprises a rib protruding from the wall surface that partitions the main flow path, and a recessed portion that is recessed from the inner surface of the upper flow path toward the outside of the main flow path, The height dimension of the rib in the lower channel is lower than the height dimension of the rib in the upper channel. The aforementioned subchannel is connected to the recessed portion. Cylinder head cover.

2. The upper flow path further comprises a wall portion that protrudes from the 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 constricted portion. A cylinder head cover according to claim 1.

3. The aforementioned sub-channel is connected to the upper channel downstream of the wall portion. The cylinder head cover according to claim 2.

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