JP6600295B2 - engine - Google Patents

Description

  The present invention relates to an engine, and more particularly to an engine capable of reducing oil consumption.

Conventionally, there are the following engines (for example, see Patent Document 1).
A cylinder head, a cylinder head cover assembled on top of the cylinder head, and a breather chamber disposed in the cylinder head cover;
The breather chamber includes an oil discharge guide groove, a blow-by gas passage space disposed above the oil discharge guide groove, and an oil discharge pipe led downward from the oil discharge guide groove.
The cylinder head has an oil sump, and the oil outlet pipe outlet is immersed in the oil stored in the oil sump.

  According to this type of engine, there is an advantage that blow-by gas in the cylinder head cover can be prevented from entering the breather chamber from the oil discharge pipe with the oil in the oil reservoir.

  In Patent Document 1, when the pressure difference between the cylinder head cover and the breather chamber increases, the oil in the oil reservoir blows up from the oil discharge pipe to the blow-by gas passage space and diffuses.

Japanese Utility Model Publication No. 57-171110 (see FIGS. 2 and 3)

<Problem> Oil consumption may increase.
In the thing of patent document 1, the oil of an oil reservoir blows up into blowby gas passage space, is re-misted, and is taken out from a breather chamber by blowby gas, and there exists a possibility that oil consumption may increase.

  The subject of this invention is providing the engine which can reduce oil consumption.

The invention specific matters of the present invention are as follows.
As illustrated in FIG. 6, a cylinder head (1), a cylinder head cover (2) assembled on the upper part of the cylinder head (1), and a breather chamber (4) disposed in the cylinder head cover (2) are provided. ,
The breather chamber (4) is led downward from the oil discharge guide groove (7), the blow-by gas passage space (8) disposed above the oil discharge guide groove (7), and the oil discharge guide groove (7). Oil drain pipe (16)
The cylinder head (1) includes an oil sump (17), and in an engine in which the pipe outlet (16a) of the oil discharge pipe (16) is immersed in the oil (18) retained in the oil sump (17).
As illustrated in FIGS. 6 and 10 (A) to 10 (C), the oil discharge guide groove (7) allows the oil (18) blown up from the pipe inlet (16c) of the oil discharge pipe (16) by the back flow. An oil receiver (26) to be received, an oil blow-up space (51) provided between the oil receiver (26) and the pipe inlet (16c), and an oil discharge direction upstream of the oil blow-up space (51). Oil mist condensation groove (52)
As illustrated in FIGS. 10A and 10B, the inner surface of the oil mist condensation groove (52) has a stepped shape that advances toward the inside of the oil mist condensation groove (52) as it approaches the upstream side in the oil discharge direction. An engine characterized by a zigzag surface.

According to the present invention, oil consumption can be reduced.
The reason is as follows.
As illustrated in FIGS. 6 and 10 (A) to 10 (C), the differential pressure in the cylinder head cover (2) and the breather chamber (4) increases, and the oil (18) in the oil reservoir (17) becomes oil. Even if it blows up from the discharge pipe (16), the oil (18) is received by the oil receiver (26), and the oil (18) re-misted in the oil blowing space (51) enters the oil mist condensing groove (52). Even if the oil flows backward, the oil mist collides with the stepped zigzag surface on the inner surface of the oil mist condensation groove (52) and is condensed, so that the oil (18) re-misted in the oil blowing space (51) is recovered. The trouble of being taken out of the breather chamber (4) by the blow-by gas (11) is suppressed, and the oil consumption can be reduced.

It is a disassembled perspective view of the cylinder head cover of the engine which concerns on embodiment of this invention, an oil receiver, and the bottom wall of a breather chamber. It is an upper section side view of an engine concerning an embodiment of the present invention. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. It is the VII-VII sectional view taken on the line of FIG. FIGS. 8A and 8B are diagrams illustrating a separated oil guide path used in an engine according to an embodiment of the present invention, FIG. 8A being a basic example, FIG. 8B being a first modification, and FIG. 8C being a second modification. It is. FIGS. 9A and 9B are diagrams illustrating a third modified example of the separated oil guiding path used in the engine according to the embodiment of the present invention, FIG. 9A being a diagram corresponding to FIG. 3 and FIG. 9B being a diagram corresponding to FIG. FIGS. 10A and 10B are diagrams illustrating a basic example of an oil discharge guide groove used in an engine according to an embodiment of the present invention, FIG. 10A is a longitudinal front view, and FIG. FIG. 10C is a cross-sectional view taken along line CC of FIG. It is a vertical perspective view of the oil discharge guide groove used with the engine which concerns on embodiment of this invention. It is a figure explaining the modification of the oil discharge pipe used with the engine which concerns on embodiment of this invention, FIG. 12 (A) is a vertical front view of a modification, FIG.12 (B) is BB of FIG. 12 (A). It is line sectional drawing. FIGS. 13A and 13B are diagrams illustrating a texture used in an engine according to an embodiment of the present invention, FIG. 13A is a basic example, FIG. 13B is a first modification, and FIG. 13C is a second modification.

  FIGS. 1-13 is a figure explaining the engine which concerns on embodiment of this invention, and this embodiment demonstrates a vertical in-line two-cylinder diesel engine.

The outline of the engine of this embodiment is as follows.
As shown in FIG. 2, the cylinder head (1) is assembled to the upper part of the cylinder block (not shown), and the cylinder head cover (2) is assembled to the upper part of the cylinder head (1). The installation direction of the crankshaft (not shown) is the front-rear direction, and one of them is the front and the other is the rear.
An oil pan (not shown) is assembled to the lower part of the cylinder block (not shown).

  The cylinder head (1) is provided with a vortex chamber (not shown). A fuel injection pump (not shown) is connected to the vortex chamber (not shown) via a fuel injection pipe (not shown) and a fuel injection nozzle (not shown). Fuel is injected.

  As shown in FIG. 7, an intake and exhaust valve device (32) is accommodated in the cylinder head cover (2), and this valve device (32) is driven by the valve operating device (33). The valve operating device (33) includes a valve operating cam (not shown), a tappet (not shown), a push rod (33c), and a rocker arm (3). The push rod (33c) is accommodated in the push rod chamber (33d) shown in FIG. The blow-by gas (11) in the crankcase (not shown) enters the cylinder head cover (2) through the push rod chamber (33d).

As shown in FIG. 1, the bottom wall (4a) of the breather chamber (4) is assembled into the cylinder head cover (2) from the lower side, and the oil supply hole (2b) is formed in the ceiling wall (2a) of the cylinder head cover (2). The oil supply hole (2b) is closed by a detachable lid (2c).
The bottom wall (4a) of the breather chamber (4) is made of synthetic resin. The cylinder head cover (2) is made of aluminum die casting.

As shown in FIG. 6, this engine includes a cylinder head (1), a cylinder head cover (2) assembled to the top of the cylinder head (1), and a breather chamber (4) disposed in the cylinder head cover (2). ).
The breather chamber (4) is led downward from the oil discharge guide groove (7), the blow-by gas passage space (8) disposed above the oil discharge guide groove (7), and the oil discharge guide groove (7). An oil discharge pipe (16) is provided.
The cylinder head (1) includes an oil reservoir (17), and a pipe outlet (16a) of the oil discharge pipe (16) is immersed in the oil (18) stored in the oil reservoir (17).
This engine has an advantage that the blow-by gas in the cylinder head cover (2) can be prevented from entering the breather chamber (4) from the oil discharge pipe (16) by the oil (18) in the oil reservoir (17). .

As shown in FIGS. 6 and 10 (A) to 10 (C), the oil discharge guide groove (7) receives the oil (18) blown up from the pipe inlet (16c) of the oil discharge pipe (16) by the back flow. An oil receiver (26), an oil blowing space (51) provided between the oil receiver (26) and the pipe inlet (16c), and an oil provided upstream of the oil blowing space (51) in the oil discharge direction A mist condensation groove (52) is provided.
As shown in FIGS. 10A and 10B, the inner surface of the oil mist condensing groove (52) advances toward the inner side of the oil mist condensing groove (52) as it approaches the upstream side in the oil discharge direction. The zigzag surface.

With the above configuration, oil consumption can be reduced.
The reason is as follows.
As shown in FIGS. 6 and 10 (A) to 10 (C), the differential pressure in the cylinder head cover (2) and the breather chamber (4) increases, and the oil (18) in the oil sump (17) is discharged. Even if it blows up from the pipe (16), the oil (18) is received by the oil receiver (26). Even if the oil (18) re-misted in the oil blowing space (51) flows back into the oil mist condensation groove (52), the oil mist is stepped zigzag on the inner surface of the oil mist condensation groove (52). The oil (18) that collides with the surface, is condensed, and is re-misted in the oil blowing space (51) is prevented from being taken out of the breather chamber (4) by the blow-by gas (11), thereby reducing oil consumption. be able to.

The reason for the oil blowing is as follows.
The blow-by gas outlet (6) of the breather chamber (4) communicates with the intake passage (not shown), and when the negative pressure of the intake passage increases due to clogging of the air cleaner (not shown), the breather chamber (4) The internal pressure decreases, the differential pressure inside and outside the breather chamber (4) increases, and the oil (18) in the oil reservoir (17) blows up from the oil discharge pipe (16) to the breather chamber (4).

As shown in FIG. 10 (B), the inner peripheral surfaces (52a) and (52b) at both ends in the width direction perpendicular to the oil discharge direction are stepped in the inner surface of the oil mist condensation groove (52) as viewed from above. The zigzag surface.
With the above configuration, when the engine is inclined to one side in the width direction and also to the upstream side in the oil discharge direction, the oil (18) is in the width direction of the oil mist condensing groove (52) having a zigzag surface. The oil (18) is unlikely to flow back to the upstream side in the oil discharge direction due to accumulation in one of the recesses on the inner peripheral surfaces (52a) and (52b) at both ends.

As shown in FIG. 10 (A), the inner bottom surface (52c) of the inner surface of the oil mist condensation groove (52) is a stepped zigzag surface.
With the above configuration, when the engine is tilted upstream in the oil discharge direction, the oil (18) accumulates in a recess in the inner bottom surface (52c) of the oil mist condensing groove (52) having a zigzag surface, and the oil (18 ) Is difficult to flow upstream in the oil discharge direction.

As shown in FIGS. 10B and 10C, the oil discharge guide groove (7) includes a partition wall (53) provided between the oil blowing space (51) and the oil mist condensation groove (52), and an oil There are provided throttle communicating portions (54a) and (54b) for communicating the blowing space (51) and the oil mist condensing groove (52).
With the above configuration, when the oil mist flowing backward from the oil blowing space (51) to the oil mist condensing groove (52) passes through the throttle communicating portions (54a) (54b), the oil is separated from the blow-by gas (11), The problem that the oil (18) re-misted in the space (51) is taken out of the breather chamber (4) by the blow-by gas (11) is suppressed, and the oil consumption can be reduced.

As shown in FIGS. 10B and 10C, the throttle communication portions (54a) and (54b) are formed between the both end edges (53a) and (53b) in the width direction of the partition wall (53) and the oil discharge guide groove (7). It is comprised by the slit provided between the both internal peripheral surfaces (7a) (7b) of the width direction. The throttle communicating portions (54a) (54b) are formed over the entire height direction along both end edges (53a) (53b) in the width direction of the partition wall (53).
With the above configuration, the oil discharged from the oil mist condensing groove (52) to the oil blowing space (51) through the throttle communicating portions (54a) (54b) is the inner bottom surface (7c) of the oil discharge guide groove (7). , And the low flow of the throttle communication portions (54a) (54b), and the problem of being blown back by the oil mist that flows back in the relatively high positions of the throttle communication portions (54a) (54b) hardly occurs.

As shown in FIG. 2, the breather chamber (4) has a blow-by gas inlet (5) on the front side and a blow-by gas outlet (6) on the rear side, with the longitudinal direction of the cylinder head cover (2) as the front-rear direction. An oil discharge guide groove (7) and a blow-by gas passage space (8) are provided at intermediate positions. The blow-by gas inlet (5) may be disposed on the rear side, and the blow-by gas outlet (6) may be disposed on the front side.
2 and 4, the blow-by gas inlet (5) is opened in the bottom wall (4a) of the breather chamber (4), and the peripheral wall (7a) of the oil discharge guide groove (7) is connected to the blow-by gas outlet ( 6) Projecting downward from the bottom wall (4a) of the breather chamber (4) toward the rocker arm (3) on the side and the blow-by gas inlet (5).

  With the above configuration, as shown in FIG. 2, the oil splashed by the rocker arm (3) on the blow-by gas outlet (6) side flows into the blow-by gas (11) along the bottom wall (4a) of the breather chamber (4). This flow is blocked by the peripheral wall (7d) of the oil discharge guide groove (7), the amount of oil entering the blow-by gas inlet (5) is reduced, and the amount of oil entering the breather chamber (4) is reduced. As a result, the oil is prevented from flowing out of the cylinder head cover (2), and the oil consumption can be reduced. In addition, the rigidity of the bottom wall (4a) of the breather chamber (4) is increased, the bottom wall (4a) is less likely to vibrate, and engine noise emission from the cylinder head cover (2) through this vibration can be reduced. it can.

As shown in FIGS. 2 and 3, a reed valve (5a) is attached to the blow-by gas inlet (5). The opened reed valve (5a) is received by the stopper plate (5b). In the inlet side oil separation chamber (9), the oil mist contained in the blowby gas (11) entering from the blowby gas inlet (5) collides with the reed valve (5a) to separate the oil, and the oil mist is separated from the chamber wall. Condensate and separate oil.
A baffle plate (45) protrudes downward from the bottom wall (4a) of the breather chamber (4) toward the blow-by gas inlet (5) side between the rocker arm (3) and the blow-by gas inlet (5). . For this reason, the flow of the blow-by gas (11) along the bottom wall (4a) of the breather chamber (4) is blocked by the baffle plate (45), and the amount of oil entering the blow-by gas inlet (5) is reduced. The baffle plate (45) is integrally formed with the bottom wall (4a) of the breather chamber (4).

As shown in FIGS. 2 and 3, the breather chamber (4) includes an inlet-side oil separation chamber (9) having a blow-by gas inlet (5) and a blow-by gas bypass passage (10). The blow-by gas (11) exiting 9) is introduced into the blow-by gas passage space (8) and the oil discharge guide groove (7) via the blow-by gas bypass passage (10).
With the above configuration, the blow-by gas (11) is continuously oil-separated in the inlet-side oil separation chamber (9) and the blow-by gas bypass passage (10), and oil separation of the blow-by gas (11) is promoted.

The inlet side oil separation chamber (9) is formed long in the front-rear direction, and the blow-by gas bypass passage (10) is formed long in the lateral direction, and these are mutually connected at the rear opening (9a) of the inlet side oil separation chamber (9). In the blow-by gas bypass passage (10), oil mist contained in the blow-by gas (11) entering from the opening (9a) is condensed on the passage wall to perform oil separation.
A first partition wall (46) that divides the inlet side oil separation chamber (9) and the blow-by gas bypass passage (10) is long in the lateral direction, and is integrally formed with the cylinder head cover (2) from the ceiling wall (2a). It protrudes downward.

  As shown in FIG. 3, the breather chamber (4) includes a partition wall (12) that partitions the blow-by gas bypass passage (10) and the blow-by gas passage space (8), and a separation oil guide path (13), and separate oil guides are provided. The passage (13) has a start end (13a) disposed in the inlet side oil separation chamber (9), an intermediate portion (13b) disposed in the start end (10a) of the blow-by gas bypass passage (10), and a terminal end ( 13c) passes under the partition wall (12) and is led out to the oil discharge guide groove (7).

With the above configuration, as shown in FIG. 3, the separated oil guiding path (13) can be formed short, and the separated oil (18) can be quickly guided to the oil discharge guide groove (7).
Further, the end portion (13c) of the separation oil guide passage (13) that passes under the partition wall (12) is closed by the oil (18) separated in the oil separation chamber (9) on the inlet side, and the separation oil guide passage (13). The blow-by gas (11) does not enter the oil discharge guide groove (7).
The second partition wall (12) that divides the blow-by gas bypass passage (10) and the oil discharge guide groove (7) is formed to be long in the lateral direction, and projects downward from the ceiling wall (2a) by being integrally formed with the cylinder head cover (2). It is installed.

As shown in FIG. 3, the separation oil guiding path (13) is constituted by a groove (14).
In this engine, the separated oil (18) separated at the inlet side oil separation chamber (9) and the start end (10a) of the blow-by gas bypass passage (10) passes from the upper opening of the groove (14) into the groove (14). And the oil (18) separated through the groove (14) with a small passage resistance can be quickly guided to the oil discharge guide groove (7).
Further, when the separation oil guiding path (13) is constituted by the groove (14), the separation oil (18) passes through the blow-by gas bypass path (10) when passing through the separation oil guiding path (13). Although there is a risk of contact with the blow-by gas (11), as described above, since the separated oil guiding path (13) can be formed short, the separated oil (18) is in contact with the blow-by gas (11). Difficult to re-mist. Further, even when the mist is re-misted, it is re-separated by the downstream blow-by gas bypass passage (10). For this reason, the separated oil (18) is hardly re-misted.

In the basic example shown in FIG. 8A, the groove (14) has a semicircular cross section.
The groove (14) is formed in a wedge shape in cross section, as in the first modification shown in FIG. 8 (B), and the inner bottom surface becomes gradually shallower toward the end portion (10b) side of the blow-by gas bypass passage (10). It may be.
The groove (14) is formed in a cross-sectional flask shape as in the second modification shown in FIG. 8 (C), the lower half (14a) is wider than the upper half (14b), and a wide passage is cut off. In the lower half (14a) of the area, the separation oil (18) is promptly guided, and in the upper half (14b) of the narrow opening area, the separation oil (18) and the blow-by gas (11) are less likely to come into contact with each other. The separated oil (18) may be less likely to be re-misted with the gas (11).

The separation oil guiding path (13) may be configured by a pipe (15) as in the third modification shown in FIGS. 9 (A) and 9 (B).
In this case, the upper surface of the separated oil guiding path (13) is covered, and the oil (18) introduced into the separated oil guiding path (13) contacts the blowby gas (11) passing through the blowby gas bypass path (10). The separated oil (18) is not easily re-misted.
The pipe (15) can also be provided on the terminal end (10b) side of the blow-by gas bypass passage (10). The separation oil guiding path (13) of the pipe (15) disposed on the terminal end (10b) side of the blowby gas bypass passage (10) has the start end (13a) disposed in the inlet side oil separation chamber (9). The intermediate portion (13b) is disposed at the end portion (10b) of the blow-by gas bypass passage (10), and the end portion (13c) passes through the lower side of the partition wall (12) and is led out to the oil discharge guide groove (7). ing.

In the basic example shown in FIGS. 10 (A) and 10 (C), the oil discharge pipe (16) has a cylindrical peripheral surface shape with no irregularities.
The oil discharge pipe (16) is provided with a flow-down oil guide groove (16b) along the axial length direction on the inner circumferential surface of the cylindrical circumferential surface as in the first modification shown in FIGS. It may be. A plurality of flow-down oil guide grooves (16b) are formed at predetermined intervals in the circumferential direction.
In this case, the oil (18) flowing down the oil discharge pipe (16) is guided vertically downward by the flow-down oil guide groove (16b), and is smoothly discharged from the oil discharge pipe (16).

As shown in FIG. 3, a partition wall (39) divides the outlet side oil separation chamber (6a) having the blow-by gas outlet (6) and the oil discharge guide groove (7). The communication ports (40) communicate with each other, and in the outlet-side oil separation chamber (6a), oil mist contained in the blow-by gas (11) is condensed on the chamber wall to perform oil separation of the blow-by gas (11).
The outlet side oil separation chamber (6a) is formed long in the lateral direction. The third partition wall (39) that partitions between the outlet side oil separation chamber (6a) and the oil discharge guide groove (7) is formed long in the lateral direction, and is connected to the bottom wall (4a) of the breather chamber (4). It is integrally molded and protrudes upward from the bottom wall (4a).

As shown in FIG. 3, the blow-by gas passage space (8) disposed above the oil discharge guide groove (7) is partitioned from the blow-by gas bypass passage (10) by the second partition wall (12), and the second The blow-by gas bypass passage (10) communicates with a bypass passage outlet (10c) provided near the oil discharge pipe (16) of the partition wall (12).
As shown in FIG. 3, the blow-by gas passage space (8) is partitioned from the outlet side oil separation chamber (6a) by the third partition wall (39), and as shown in FIG. 39) is communicated with the outlet side oil separation chamber (6a) through a gap (39b) between the upper edge (39a) of the cylinder head cover (2) and the ceiling wall (2a) of the cylinder head cover (2). The vertical width of the gap (39b) is formed wider than the side closer to the side away from the blow-by gas outlet (6).
As shown in FIG. 2, the blow-by gas (11) flowing out from the bypass passage outlet (10c) passes through the blow-by gas passage space (8) and flows into the outlet-side oil separation chamber (6a).

The inner surface of the breather chamber (4), the upper surface of the bottom wall (4a) of the breather chamber (4), the inner peripheral surface of the separation oil guide groove (14), the inner peripheral surface of the separation oil guide pipe (15), and the oil discharge guide groove The following surface treatment can be performed on the inner surface of (7) and the whole or a part of the inner peripheral surface of the oil discharge pipe (16).
An oil repellent layer such as a fluororesin is provided. In this case, the separated oil (18) quickly passes through the surface of the oil repellent layer, and the oil (18) is quickly discharged.
Performs embossing. In this case, the oil retention of the machined surface is enhanced, and a continuous oil film is formed by the oil (18) flowing through the machined surface, and the subsequent oil (18) smoothly passes through the surface of the oil film, and the separated oil (18). Are discharged promptly.
In the basic example shown in FIG. 13 (A), the cross-hatching (38) uses a cross hatching groove. The embossed portion (38) includes a turtle shell groove as in the first modification shown in FIG. 13 (B), and a parallel groove along the inclination of the oil discharge guide surface (7b) as in the second modification shown in FIG. 13 (C). It may be.

  (1) ... Cylinder head, (2) ... Cylinder head cover, (3) ... Rocker arm, (4) ... Breather chamber, (5) ... Blow-by gas inlet, (6) ... Blow-by gas outlet, (7) ... Oil discharge guide Groove, (7d) ... peripheral wall, (8) ... blow-by gas passage space, (9) ... inlet side oil separation chamber, (10) ... blow-by gas bypass passage, (11) ... blow-by gas, (12) ... second Partition wall, (13) ... Separation oil guiding path, (13a) ... Start end, (13b) ... Intermediate part, (13c) ... End part, (16) ... Oil discharge pipe, (16a) ... Pipe outlet, (16c) ... Pipe inlet, (17) ... Oil sump, (18) ... Oil, (26) ... Oil receiver, (51) ... Oil blowing up space, (52) ... Oil mist condensation groove, (52a) (52b) ... Width direction (52c)... Inner bottom surface, (53)... Partition wall, (54a) and (54b).

Claims (7)

A cylinder head (1), a cylinder head cover (2) assembled on top of the cylinder head (1), and a breather chamber (4) disposed in the cylinder head cover (2);
The breather chamber (4) is led downward from the oil discharge guide groove (7), the blow-by gas passage space (8) disposed above the oil discharge guide groove (7), and the oil discharge guide groove (7). Oil drain pipe (16)
The cylinder head (1) includes an oil sump (17), and in an engine in which the pipe outlet (16a) of the oil discharge pipe (16) is immersed in the oil (18) retained in the oil sump (17).
The oil discharge guide groove (7) includes an oil receiver (26) for receiving the oil (18) blown up from the pipe inlet (16c) of the oil discharge pipe (16) by the reverse flow, and the oil receiver (26) and the pipe inlet (16c). ) And an oil mist condensing groove (52) provided upstream of the oil blowing space (51) in the oil discharge direction,
The engine characterized in that the inner surface of the oil mist condensing groove (52) is a stepped zigzag surface that advances toward the inner side of the oil mist condensing groove (52) as it approaches the upstream side in the oil discharge direction. The engine according to claim 1,
Of the inner surface of the oil mist condensing groove (52), the inner peripheral surfaces (52a) and (52b) at both ends in the width direction perpendicular to the oil discharge direction as viewed from above are stepped zigzag surfaces. A featured engine. The engine according to claim 1 or 2,
An engine characterized in that, of the inner surface of the oil mist condensation groove (52), the inner bottom surface (52c) is a stepped zigzag surface. The engine according to any one of claims 1 to 3,
The oil discharge guide groove (7) includes a partition wall (53) provided between the oil blowing space (51) and the oil mist condensation groove (52), the oil blowing space (51), and the oil mist condensation groove (52). An engine comprising a throttle communication portion (54a) (54b) for communicating with each other. The engine according to any one of claims 1 to 4, wherein
With the longitudinal direction of the cylinder head cover (2) as the front-rear direction, the breather chamber (4) has a blow-by gas inlet (5) at one end in the front-rear direction and a blow-by gas outlet (6) at the other end in the front-rear direction. The oil discharge guide groove (7) and the blow-by gas passage space (8) are provided at the positions, and the cylinder head cover (2) covers the rocker arm (3).
The blow-by gas inlet (5) is opened in the bottom wall (4a) of the breather chamber (4), and the peripheral wall (7d) of the oil discharge guide groove (7) is connected to the rocker arm (3) on the blow-by gas outlet (6) side. An engine characterized by projecting downward from the bottom wall (4a) of the breather chamber (4) toward the blow-by gas inlet (5). The engine according to any one of claims 1 to 5,
The breather chamber (4) includes an inlet-side oil separation chamber (9) having a blow-by gas inlet (5) and a blow-by gas bypass passage (10), and a blow-by gas (11) exiting the inlet-side oil separation chamber (9). ) Is introduced into the blow-by gas passage space (8) and the oil discharge guide groove (7) through the blow-by gas bypass passage (10). The engine according to claim 6, wherein
The breather chamber (4) includes a partition wall (12) that partitions the blow-by gas bypass passage (10) and the blow-by gas passage space (8), and a separation oil guide path (13). The separation oil guide path (13) The portion (13a) is disposed in the inlet side oil separation chamber (9), the intermediate portion (13b) is disposed in the start end portion (10a) of the blow-by gas bypass passage (10), and the end portion (13c) is disposed in the partition wall (12). The engine is characterized in that it passes through the lower part of the engine and is led out to the oil discharge guide groove (7).

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