JP7291644B2 - Engine with blow-by gas recirculation device - Google Patents

Description

The present invention relates to an engine with a blow-by gas recirculation device, such as an industrial engine mounted on a tractor or construction machine, or an engine for a vehicle.

The engine is equipped with a blow-by gas recirculation device that recirculates the blow-by gas that accumulates in the crankcase to the intake passage such as the intake manifold, mixes it with fresh air-fuel mixture and burns it, and prevents it from being released into the atmosphere as it is. It is In an engine with a blow-by gas recirculation device, it is desirable to remove liquid components such as oil (oil mist) and water contained in the blow-by gas as much as possible before returning the blow-by gas to the intake passage.

Therefore, conventionally, a configuration is often adopted in which the liquid component is returned to the intake passage from the crankcase through the cylinder head and the head cover so that the liquid component is easily trapped inside the engine. As such examples, those disclosed in Patent Document 1 and Patent Document 2 are known.

JP 2017-141769 A JP 2019-199809 A

When extracting the blow-by gas from the head cover, an oil separation chamber is often provided inside the head cover for capturing and separating the oil component from the blow-by gas. In Patent Document 1, the oil separation chamber is the portion of the large circular hole (55) in which the filter (13) is arranged (see FIGS. 1 to 3 of Patent Document 1). It is a portion of the gas passage (26) (see FIG. 7 of Patent Document 2). The oil component separated in the oil separation chamber drops or flows down and is returned into the engine (inside the crankcase).

However, it has been found that the provision of the oil separation chamber may cause trouble. That is, depending on conditions such as when a work machine (such as a tractor) on which an engine is mounted travels on a slope, oil may accumulate in the oil separation chamber due to the slope and flow back into the intake passage together with blow-by gas. There is a problem that so-called "oil is taken out".

The object of the present invention is to take out blow-by gas from the head cover and return it to the intake passage through further structural improvements. An object of the present invention is to provide an engine with an improved blow-by gas recirculation device.

The present invention provides an engine with a blow-by gas recirculation device,
The blow-by gas in the crankcase is guided to the intake passage through the oil separation chamber provided inside the head cover,
The intake passage has a cover intake passage portion provided on the head cover in communication with the oil separation chamber,
The bottom wall of the oil separation chamber is provided with a return hole through which the oil captured in the oil separation chamber can fall,
A raising mechanism is provided for increasing the vertical length of the oil separation chamber ,
The raising mechanism is configured by interposing an intermediate gas case having an internal space that allows communication between the oil separation chamber and the cover intake passage between the head cover and the cover intake passage,
A lower partition member is interposed between the head cover and the intermediate gas case, and an upper partition member is interposed between the intermediate gas case and the cover intake passage,
A communication hole for communicating a fluid is formed in each of the lower partition member and the upper partition member,
The communication hole formed in the lower partition member is located in the central region in the lateral direction of the oil separation chamber, and the communication hole formed in the upper partition member is located in the lateral center of the upper partition member. The communicating holes are arranged separately and separated from each other in the front-rear direction .

In this case, the intermediate gas case is advantageously arranged directly above the oil separation chamber .

Regarding the present invention, refer to claims 3 to 5 for characteristic configurations and means other than the above-described configurations (means).

According to the present invention, the vertical length of the oil separation chamber is increased by the raising mechanism as compared with the conventional product, and the capacity (volume) is also increased. Therefore, even if oil accumulates in the oil separation chamber due to the tilted position of the engine, there is a sufficient space above the oil separation chamber, and the space has the effect of capturing the oil component in the blow-by gas. The effect of suppressing or eliminating the above-mentioned "oil take-out" can be obtained

As a result, further structural improvements were made to take out the blow-by gas from the head cover and return it to the intake passage. An engine with a blow-by gas recirculation device can be provided.

Front view of an industrial diesel engine A plan view of the engine shown in FIG. Left side view showing head cover with cover intake passage Top view of head cover with cover intake passage Bottom view of head cover with cover intake passage (A) Plan view of blow-by gas outlet, (B) Bottom view of cover intake passage (A) Front view of the cover intake passage, (B) is a cross-sectional view along the ZZ line of (A) Principal parts of the blow-by gas outlet are shown, (A) longitudinal sectional view, (B) transverse sectional view. (A) Plan view of upper gasket, (B) Plan view of intermediate gas case, (C) Plan view of lower gasket (A) Enlarged side view showing structure of inflow reed valve, (B) Enlarged side view showing structure of return reed valve An exploded perspective view showing the structure of the head cover, cover intake passage, etc.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an engine equipped with a blow-by gas recirculation device according to the present invention will be described below with reference to the drawings for a case where it is applied to an industrial diesel engine.

As shown in FIGS. 1 and 2, an industrial diesel engine (hereinafter simply referred to as engine) E has a cylinder head 2 mounted on the top of a cylinder block 1 and a head cover 3 on the top of the cylinder head 2. An oil pan 4 is assembled to the lower part of the cylinder block 1. - 特許庁A transmission case 5 is attached to the front end of the cylinder block 1 , an engine cooling fan 6 is arranged in front of the transmission case 5 , and a flywheel 7 is arranged in the rear of the cylinder block 1 . The upper half of the cylinder block 1 is composed of cylinders (notation is omitted), and the lower half thereof is composed of a crankcase 1B.

In the front part of the engine E, a drive pulley 8 attached to the shaft end of a crankshaft (not shown), a drive fan pulley 6A for the engine cooling fan 6, and a transmission belt 10 spanning the passive pulley 9A for the dynamo (alternator) 9, A water flange 21 and the like are provided. On the left side of the engine E, an exhaust manifold 11, a supercharger 12, a starter (not shown), an oil filter 14, and the like are installed. An intake manifold 15, a fuel injection pump housing 16, a stop solenoid 17, etc. are installed on the right side of the engine E, and three injectors 18, a compressor upstream intake passage 19, a compressor downstream intake passage 20, etc. are arranged above. there is

The compressor upstream intake passage 19 includes a cover intake passage portion 19A and a bent pipe 19B that connects the cover intake passage portion 19A and the compressor housing 12A of the supercharger 12 . The compressor downstream side intake passage 20 includes a starting end side pipe 20A that is connected to the compressor housing 12A and arranged across the head cover 3 directly above, and a terminal end side pipe 20B that connects the starting end side pipe 20A and the intake manifold 15. configured as follows. The bent tube 19B, the start side tube 20A, and the end side tube 20B may be made of a flexible material such as rubber or a metal pipe.

As shown in FIGS. 1, 2 and 3 to 5, the engine E has a blow-by gas recirculation system configured to guide the blow-by gas in the crankcase 1B through the inside of the head cover 3 to the intake passage k. Device A is equipped. The head cover 3 is a substantially bottomless box-shaped (upper lid-shaped) component that is assembled to the cylinder head 2 across a valve gear (not shown), and includes a cover main body 3H, a gas outlet cover 3B, an intermediate gas case 3D, and the like. It consists of multiple parts. An engine oil supply hole 22 is provided in the rear portion of the top wall 3C of the cover body 3H, and a plurality of ribs 3a are formed inside (see FIG. 5).

The intake passage k has a cover intake passage portion 19A provided in the gas outlet cover 3B of the head cover 3, a main oil separation chamber 26 of the blow-by gas outlet portion 3A formed in the front portion of the cover main body 3H, and a cover It communicates with the intake passage portion 19A. The cover intake passage portion 19</b>A is configured as part of the compressor upstream side intake passage 19 that connects the air cleaner 23 (see FIG. 2 ) and the supercharger 12 . Note that the intake passage k is a concept including all passages such as the air cleaner 23 and the intake manifold 15 for sending the air a to the combustion chamber (not shown).

An open box-shaped blow-by gas outlet 3A partitioned vertically by a bottom wall 25 positioned between the top and bottom of the head cover 3 is formed in the upper front portion of the cover main body 3H. As shown in FIGS. 3 and 11, a gas outlet cover 3B is bolted onto the blow-by gas outlet 3A via an intermediate gas case 3D. A lower gasket (partition member or lower partition member) 35 is provided between the upper and lower portions of the blow-by gas outlet portion 3A and the intermediate gas case 3D, and an upper gasket is provided between the upper and lower portions of the intermediate gas case 3D and the gas outlet cover 3B. (Partition member or upper partition member) 46 are interposed respectively.

Here, a brief description will be given of the major functions of the blow-by gas recirculation device A (recirculation portion to the intake passage k). As shown in FIGS. 3, 4 and 11, the blow-by gas g flowing from the cylinder block 1 into the internal space of the head cover 3 passes through the inflow reed valve 31 and passes through the main internal space of the blow-by gas outlet 3A. Enter the oil separation chamber 26 . The blow-by gas g that has entered the main oil separation chamber 26, which is also called a CCV (crankcase ventilation) chamber, passes through the lower communication hole 38 of the lower gasket 35, the additional oil separation chamber 50 which is the internal space of the intermediate gas case 3D, and the upper gasket 46. It is returned to the cover intake passage portion 19A, that is, the intake passage k through the upper communication hole 49 and a communication passage 40 (described later).

Next, the head cover 3 and the cover intake passage portion 19A will be described in detail.
As shown in FIGS. 3 to 8, an upwardly open blow-by gas outlet 3A is formed at the front end of the head cover 3, which has a rounded square shape (oval shape) in plan view. The blow-by gas outlet 3A has a main oil separation chamber 26, which is a space surrounded by an up-and-down partition wall 24 and a bottom wall 25, and a joint surface 27, which is the upper edge of the head cover. 3 is formed.

The main oil separation chamber 26 has an opening of a complex shape with curved protruding portions and sloping portions that avoid multiple bolted locations [see FIG. 6(A)]. The bottom surface 25A, the sink bottom surfaces 25B, 25B respectively formed on the front and rear sides of the main bottom surface 25A in a deep state, and the groove bottom surface 25C extending back and forth on the right side of the main bottom surface 25A and spanning the front and rear sink bottom surfaces 25B, 25B. and A circular inflow hole 31C penetrating vertically through the bottom wall 25 and an inflow reed valve 31 acting on the inflow hole 31C are provided in a horizontal (to the left) position at the front-rear central portion of the main bottom surface 25A. In addition, in FIG. 6(A), only the essential part of the right half of the inflow reed valve 31 is depicted.

As shown in FIGS. 5, 8, and 10A, the inflow reed valve 31 has a space inside the head cover 3 other than the main oil separation chamber 26, that is, a cover main body space 3h inside the cover main body 3H. to the main oil separation chamber 26. The inflow reed valve 31 is constructed by bolting a thin inflow valve body 31A arranged on the main bottom surface 25A and a thick inflow valve guide 31B to the bottom wall 25 at their root sides. there is A round tip portion 31a (see FIG. 6A) of the inflow valve body 31A is arranged above an inflow hole 31C formed in the bottom wall 25 so as to open in the main bottom surface 25A, and normally serves as a cover for the inflow hole 31C. (valve closed).

The thickness d of the peripheral portion 25a forming the inflow hole 31C in the bottom wall 25 (main bottom surface 25A) is set to be smaller than the diameter r of the inflow hole 31C (r>d). More specifically, the thickness d of the peripheral portion 25a is set to be less than half the diameter r of the inflow hole 31C, preferably in the range of 0.5r≧d≧0.3r. A downstream corner (upper corner) 47 in the blow-by gas flow direction of the inflow hole 31C is rounded. The upstream corner (lower corner) 48 may be rounded with a larger curvature than the downstream corner 47 .

The sink bottom surface 25B has an inclined surface (or an inclined curved surface) 32 which becomes lower as it goes from the front and back of the inflow reed valve 31 to the front or rear, and a very low surface 33 continuing to the lower side of the inclined surface 32 (FIG. 8). (A)]. Return holes 33a, 33a penetrating vertically are formed in the respective very low surfaces 33, 33 of the bottom wall 25, and a return reed valve 34 (see FIG. 5) acting on these return holes 33a is provided.

As shown in FIGS. 5 and 10B, the return reed valve 34 includes a return valve body 34A in contact with the opposite side of the bottom wall 25 to the extremely low surface 33, that is, the extremely low back surface 33A, and a thick return valve. The guides 34B are bolted to the bottom wall 25 at their base sides. The return reed valve 34 is provided in an upside-down posture with respect to the inflow reed valve 31, and normally, the return hole 33a is lightly closed by the tip portion 34a of the return valve body 34A, or the return valve body 34A is slightly closed. The return hole 33a is opened very slightly due to the drooping displacement.

Each of the return reed valves 34, 34 is arranged in a lateral orientation with the tip portion 34a on the left side, and causes the oil component captured from the blow-by gas g in the main oil separation chamber 26 to flow down from the return hole 33a to the cover main body. This is the place to return to the space 3h. The diameter of each return hole 33a is smaller than the diameter of the inflow hole 31C. The inflow valve body 31A and the return valve body 34A, and the inflow valve guide 31B and the return valve guide 34B may be the same parts.

As shown in FIGS. 3 to 5 and 11, a gas outlet cover 3B is bolted onto the blow-by gas outlet 3A via an intermediate gas case 3D. and a cover intake passage portion 19A. The lid cover portion 36 has the same outline shape as the blow-by gas outlet portion 3A in a plan view, and is attached to the head cover by bolting at three locations across the three parts of the lower gasket 35, the intermediate gas case 3D, and the upper gasket 46. 3 is fixed.

As shown in FIGS. 6(B), 7 and 11, the cover air intake passage portion 19A is arranged such that the passage end portion 19b is closer to the outside in the longitudinal direction of the head cover 3 than the passage start portion 19a. It is formed in a meandering passage that bends to the More specifically, the cover air intake passage portion 19A includes a passage start end portion 19a and a passage end portion 19b extending in the lateral direction crossing the longitudinal direction (front-rear direction) of the head cover and parallel to each other, and the end of the passage start portion 19a and the passage end portion 19b. It is formed into a meandering passage having a crank shape (substantially Z shape) when viewed from the top and bottom direction.

The intermediate passage portion 19c is formed in a groove-like passage portion having a downward U-shaped cross section, and an opening 37 at the lower end thereof has a shape similar to that of the intermediate passage portion 19c in a plan view and opens downward. formed. Further, the lid cover portion 36 is formed with a gas passage recess 36a which is located behind the opening 37 and opens downward, and is formed with three bolt holes 3b.

As shown in FIGS. 3, 6B, and 7B, the lid cover portion 36 is formed with a labyrinth-like communication passage 40 communicating with the main oil separation chamber 26 . The communication passage 40 is composed of a gas passage recess 36a of the gas outlet cover 3B and an upper gasket 46 serving as a lid for closing the opening of the recess 36a. The gas passage recess 36a of the gas outlet cover 3B communicates with the downstream end of the passage intermediate portion 19c in the direction of gas flow.

As shown in FIGS. 6(B) and 9(A), the right end of the gas passage recess 36a is located above the upper communication hole 49 of the upper gasket 46 and is connected to the intermediate passage portion 19c. It has a narrow, fore-and-aft terminating recess 42 . The gas outlet cover 3B has a right protruding wall 43 that protrudes rearward toward the gas passage recess 36a along the terminal recess 42, and a right protruding wall 43 that protrudes forward toward the gas passage recess 36a on the left side of the right protruding wall 43. An intermediate projection wall 44 is formed. Therefore, the blow-by gas g flowing from the upper communication hole 49 passes through the connecting passage 40, which is a path bent in a labyrinth shape (crank shape) by the middle protruding wall 44 and the right protruding wall 43, and then advances to the intermediate passage portion 19c. is configured as

As shown in FIG. 6(B), a heat insulating portion D is provided between a portion of the connecting passage 40 excluding the intake passage side end (terminating recess 42) and the cover intake passage portion 19A, more specifically, the passage intermediate portion 19c. is provided. The heat insulating portion D is composed of a curved elongated hole (an example of a recess or hole) 41 formed in the gas outlet cover 3B in a state of opening to the side surface of the gasket of the gas outlet cover 3B. , are covered by an upper gasket 46 .

The curved elongated hole 41 is formed between the passage intermediate portion 19c and the gas passage recess 36a so as to be partitioned by thin front and rear rib-like walls 45, 45, respectively. Due to the presence of the upper gasket 46, the curved elongated hole 41 becomes a closed space.

As shown in FIGS. 9A and 11, the upper gasket 46 is a thin plate-like (sheet-like) gasket having one upper communication hole 49 and three bolt insertion holes 39. , the upper communication hole 49 is provided at a position substantially in the center of the left and right at the rear end.
As shown in FIGS. 9C and 11, the lower gasket 35 is a thin plate-like (sheet-like) gasket having one lower communication hole 38 and three bolt insertion holes 39. , the lower communication hole 38 is provided at a position slightly to the right at the front end. The diameter of the lower communication hole 38 is larger than the diameter of the upper communication hole 49, but the size relationship between them is not limited to this.

As shown in FIGS. 9B and 11, the intermediate gas case 3D is a housing having three bolt insertion holes 39 on its periphery and an additional oil separation chamber 50, which is one large internal space. . The additional oil separation chamber 50, which is a large hole penetrating vertically, has a trapezoidal shape with the short side on the right side when viewed from the top and bottom, and is made of a metal material such as aluminum die-cast or a synthetic resin material. there is

As shown in FIGS. 3 and 11, the lower gasket 35 is sandwiched between the joint surface 27 of the blow-by gas outlet portion 3A and the bottom surface 51 of the intermediate gas case 3D, and is provided in the main oil separation chamber. 26 and the additional oil separation chamber 50 are communicated only through the lower communication hole 38 . The upper gasket 46 is sandwiched between the upper surface 52 of the intermediate gas case 3D and the joint lower surface 36b of the lid cover portion 36, and the communication passage 40 and the additional oil separation chamber 50 are communicated only at the upper communication hole 49. are communicated.

Next, the raising mechanism B will be explained. As shown in FIGS. 3 and 11, a raising mechanism B is provided to increase the height dimension (vertical length) of the main oil separation chamber 26 . In the raising mechanism B, an intermediate gas case 3D having an additional oil separation chamber 50 for communicating the main oil separation chamber 26 and the cover intake passage 19A is interposed between the head cover 3 and the cover intake passage 19A. It is composed by The intermediate gas case 3D is arranged directly above the main oil separation chamber 26. As shown in FIG. The cover main body space 3h, the main oil separation chamber 26, and the additional oil separation chamber 50 all correspond to the "inside cover gas passage" which is the path of the blow-by gas g in the head cover 3.

The main oil separation chamber 26 and the additional oil separation chamber 50 constitute an oil separation chamber b, and the sum of the height h1 of the main oil separation chamber 26 and the height h2 of the additional oil separation chamber 50 is the oil separation The height dimension h of the chamber b is (h1+h2=h). That is, the intermediate gas case 3D is a main element of the raising mechanism B that increases the height dimension of the oil separation chamber b from h1 (conventional product) to h (present invention product). Both the additional oil separation chamber 50 and the main oil separation chamber 26 are oil separation chambers b. It is possible to set

In the raising mechanism B, a lower gasket 35 as a lower partition member for vertically partitioning the oil separation chamber b and an upper gasket 46 as an upper partition member are provided. An upper communicating hole 49 is formed in each of 46 . A lower gasket 35 is provided between the blow-by gas outlet portion 3A (head cover 3) and the intermediate gas case 3D, and an upper gasket 46 is provided between the intermediate gas case 3D and the gas outlet cover 3B (cover intake passage portion 19A). intervened. The upper and lower communicating holes 38 and 49 are arranged in the central portion of the upper and lower gaskets 35 and 46 in the left-right direction (an example of the lateral direction), and the ends (lower communicating holes 38 are arranged at the front end, and the upper communication hole 49 is arranged at the rear end.

[About actions and effects]
In the previous engine, the oil separation chamber was formed only by the main oil separation chamber 26, but when the engine E continues to lean greatly to the left or right due to running on a slope, the return hole 33a will be at a high position. As a result, the oil component that is not discharged downstream accumulates in the main oil separation chamber 26 and flows into the cover intake passage portion 19A together with the blow-by gas.

In the present invention, the height dimension h of the main oil separation chamber 26 is substantially increased from the previous height dimension h1 (h1→h1+h2) by the raising mechanism B using the intermediate gas case 3D. b (see FIG. 3). Therefore, even if the oil accumulates in the oil separation chamber b (the main oil separation chamber 26) due to the tilted position of the engine, it is necessary to ensure that there is a sufficient space above it, or that the oil component in the blow-by gas in the additional oil separation chamber 50 is sufficient. The effect of suppressing or eliminating the above-mentioned "oil carry-out" is obtained by adding the trapping action.

A lower gasket 35 having a lower communication hole 38 is provided at the blow-by gas outlet portion 3A to partition the oil separation chamber b into the main oil separation chamber 26 and the additional oil separation chamber 50 . Therefore, even if the engine is repeatedly tilted back and forth and left and right (for example, when the tractor travels on rough terrain), the trapped oil components accumulate in the main oil separation chamber 26 and are shaken and undulated. , the lower gasket 35 suppresses (controls) the agitation of the oil and the resulting wobbling and waving, and as a result, the effect of suppressing "oil take-out" is obtained.

In addition, since the lower communication hole 38 is formed in the central region in the horizontal direction as the main oil separation chamber 26, the lower communication hole 38 can be Since it can always be positioned above the main oil separation chamber 26, there is also the effect of exhibiting a good oil supplementation action while suppressing "oil carry-out".

Since the upper gasket 46 is also provided, two upper and lower gaskets 35 and 46 are provided, and the lower communicating hole 38 and the upper communicating hole 49 are separately arranged in the front and rear directions. Even if it is tilted back and forth, it is possible to suppress the wobbling and rippling of the oil, thereby enhancing the effect of suppressing the "taking out of the oil".

In the oil separation chamber b, the two upper and lower gaskets 46 and 35 control the passage of the blow-by gas g from the inflow hole 31C to the communication passage 40 so as to form a crank-like path, thereby reducing the flow velocity of the blow-by gas. As a result, the action of dropping the oil mist onto the wall surface and the action of capturing the oil mist due to the inertia of changing the flow direction are promoted.
Therefore, even if some oil is carried out from the main oil separation chamber 26 through the lower communication hole 38, the additional oil separation chamber 50 captures the oil component, thereby suppressing or eliminating "oil carry-out." Further, by directing the flow direction of the blow-by gas away from the area where the oil is likely to accumulate and be carried out, there is an effect of reducing the "carrying out of the oil".

In addition, the freezing of moisture in the blow-by gas has the following effects. Conventionally, the moisture in the blow-by gas condenses in the passage that returns the CCV to the intake, and after adhering to the wall surface, it may freeze and grow into ice blocks, thereby blocking the blow-by gas passage and increasing the internal engine pressure. There was a risk of an abnormal rise. In order to improve this, it is effective to reduce the thickness (path length) of the easily cooled portion in the passage of the blow-by gas. For example, there are locations where the flow velocity is throttled and the heat transfer coefficient increases, and locations where the wall surface temperature in the blow-by gas passage is low. Specifically, the inflow hole 31C, the lower communication hole 38, and the upper communication hole 49 in the bottom wall 25 of the main oil separation chamber 26 are mentioned.

In the inflow hole 31C, the diameter r and the thickness d are set so as to satisfy d<r/2 (eg, r=6 mm, d=2.5 mm). By rounding the corners of the inlet 31C, freezing and formation of ice blocks in the inlet 31C are suppressed. Also, since the lower communication hole 38 of the lower gasket 35 and the upper communication hole 49 of the upper gasket 46 are sufficiently thin, even if ice blocks are generated in the inflow hole 31C and the upper and lower communication holes 49, 38, It will be blown away by the increase in engine internal pressure, and blockage due to freezing will not occur.

[Another embodiment]
The oil separation chamber b may be provided with only one lower or upper partition member (gasket) 35 (or 46). Also, the mounting structure of the partition member (gasket) 35 (or 46) may be one that is installed inside either the main oil separation chamber 26 or the additional oil separation chamber 50. FIG.

1B crankcase 3 head cover 3D intermediate gas case 19A cover intake passage portion 25 bottom wall 25a peripheral portion 26 main oil separation chamber (oil separation chamber)
31 gas check valve 31C inflow hole 33a return hole 35 lower partition member 38 communication hole (lower communication hole)
46 Upper partition member 49 Communication hole (upper communication hole)
50 Internal space (additional oil separation chamber)
B Raising Mechanism b Oil Separation Chamber k Intake Passage

Claims (5)

The blow-by gas in the crankcase is guided to the intake passage through the oil separation chamber provided inside the head cover,
The intake passage has a cover intake passage portion provided on the head cover in communication with the oil separation chamber,
The bottom wall of the oil separation chamber is provided with a return hole through which the oil captured in the oil separation chamber can fall,
A raising mechanism is provided for increasing the vertical length of the oil separation chamber ,
The raising mechanism is configured by interposing an intermediate gas case having an internal space that allows communication between the oil separation chamber and the cover intake passage between the head cover and the cover intake passage,
A lower partition member is interposed between the head cover and the intermediate gas case, and an upper partition member is interposed between the intermediate gas case and the cover intake passage,
A communication hole for communicating a fluid is formed in each of the lower partition member and the upper partition member,
The communication hole formed in the lower partition member is located in the central region in the lateral direction of the oil separation chamber, and the communication hole formed in the upper partition member is located in the lateral center of the upper partition member. An engine with a blow-by gas recirculation device , wherein the communication holes are arranged separately and separated from each other in the front-rear direction . 2. An engine with a blow-by gas recirculation system according to claim 1 , wherein said intermediate gas case is arranged directly above said oil separation chamber . 3. An engine with a blow-by gas recirculation system according to claim 1, wherein said lower and upper partition members partition said oil separating chamber into upper and lower parts. The bottom wall is provided with an inflow hole that allows blow-by gas in the head cover to flow into the oil separation chamber,
4. The engine with a blow-by gas recirculation system according to claim 3, wherein said communicating hole facing said inflow hole and said inflow hole are configured to have a positional relationship apart from each other in the lateral direction. 5. The engine with a blow-by gas recirculation system according to claim 4, wherein the portion of the bottom wall where the inflow hole is provided is set at a higher position than the portion where the return hole is provided.

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