WO2020179812A1

WO2020179812A1 - Oil separator

Info

Publication number: WO2020179812A1
Application number: PCT/JP2020/009078
Authority: WO
Inventors: 佑樹氷室; 博之渡邊; 大介山之内; 哲哉竹永
Original assignee: いすゞ自動車株式会社
Priority date: 2019-03-06
Filing date: 2020-03-04
Publication date: 2020-09-10
Also published as: JP2020143628A

Abstract

This oil separator 100 is provided with a blow-by gas passage 20 which is provided inside of a head cover 10 of an internal combustion engine 1 and which has a bottom wall 30, recesses 31-33 which are provided in the bottom wall 30 and which collect oil separated from the blow-by gas, and oil discharge openings D which are provided in the recesses 31-33 and which discharge oil collected in the recesses 31-33.

Description

Oil separator

The present disclosure relates to an oil separator, particularly an oil separator for separating oil from blow-by gas of an internal combustion engine.

In an internal combustion engine, an oil separator is known that separates oil from blow-by gas while returning blow-by gas that has leaked into the crankcase from the gap between the piston and the cylinder to the intake passage.

Further, as an oil separator, a structure including a blow-by gas passage provided inside the head cover of an internal combustion engine and an oil discharge port provided on the bottom wall of the blow-by gas passage is known.

Japanese Patent Application Laid-Open No. 2005-23824

However, in the above oil separator, the negative pressure generated by the blow-by gas flowing through the blow-by gas passage may cause the oil that is about to be discharged from the oil discharge port to be sucked into the blow-by gas passage. As a result, oil may not be smoothly discharged from the oil discharge port.

Therefore, the present disclosure has been devised in view of such circumstances, and an object thereof is to provide an oil separator that can smoothly discharge oil separated from blow-by gas.

According to an aspect of the present disclosure, an oil separator for separating oil from blow-by gas of an internal combustion engine, the blow-by gas passage having a bottom wall portion provided inside a head cover of the internal combustion engine, and An oil separator provided on the bottom wall and provided with a recess for storing oil separated from blow-by gas and an oil discharge port provided on the recess for discharging the oil stored in the recess. Provided.

Preferably, the blow-by gas passage is connected to the first side wall portion so as to intersect with the first side wall portion, and the blow-by gas flowing along the first side wall portion collides with and bends the second side wall portion. And the recess is located at the connecting portion of the first and second side walls.

Preferably, the first side wall portion has a protrusion portion, and the protrusion portion is separated upstream from the second side wall portion in a first direction which is a flow direction of blow-by gas along the first side wall portion. The recess is located at a position behind the protrusion in the first direction.

Preferably, the protrusion has an inclined surface that is inclined in a direction away from the first side wall portion toward the first direction.

Preferably, the second side wall portion has a base end portion that is connected to intersect the first side wall portion and a tip end portion that is bent toward the upstream side in the first direction.

Preferably, the concave portion is located at a connecting portion between the first side wall portion and the bottom wall portion, and the concave portion is arranged below the first side wall portion.

Preferably, a cover member for covering the outlet of the oil discharge port from below is further provided.

The oil separator according to the present disclosure can smoothly discharge the oil separated from the blow-by gas.

FIG. 1 is an overall configuration diagram of an internal combustion engine including an oil separator. FIG. 2 is a diagram schematically showing the internal structure of the head cover. FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is an enlarged cross-sectional view showing the IV section in FIG. FIG. 5 is an enlarged sectional view showing a V portion of FIG. FIG. 6 is an enlarged cross-sectional view showing the VI portion of FIG. FIG. 7 is a schematic perspective view of the recess shown in FIG. FIG. 8 is a schematic perspective view of the recess shown in FIG. FIG. 9 is a schematic perspective view of the recess shown in FIG. FIG. 10 is a partial cross-sectional view of the second oil separator shown in FIG. FIG. 11 is an enlarged cross-sectional view showing a first modification. FIG. 12 is a diagram showing a second modification.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments. Further, the up, down, front, back, left, and right directions shown in the drawing are merely defined for convenience of description.

First, the overall configuration of the internal combustion engine 1 including the first oil separator 100 as the oil separator will be described with reference to FIG. In the figure, the white arrow A indicates the flow of intake air or compressed air, and the shaded arrow B indicates the flow of blow-by gas. The black arrow G indicates the flow of exhaust gas.

As shown in FIG. 1, the internal combustion engine 1 is a multi-cylinder compression ignition type internal combustion engine, that is, a diesel engine mounted on a vehicle (not shown). The vehicle is a large vehicle such as a truck. However, there are no particular limitations on the types, types, applications, etc. of the vehicle and the internal combustion engine 1. For example, the vehicle may be a small vehicle such as a passenger car, and the internal combustion engine 1 is a spark ignition internal combustion engine, that is, a gasoline engine. Is also good.

The internal combustion engine 1 includes an engine body 2, an intake passage 3, and an exhaust passage 4. Although not shown, the engine main body 2 includes structural parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts such as a piston, a crankshaft, and a valve mechanism housed therein. A head cover 10 is connected to the upper part of the cylinder head.

The intake passage 3 is mainly defined by an intake manifold 3a connected to the engine body 2 (in particular, a cylinder head) and an intake pipe 3b connected to an upstream end of the intake manifold 3a. The intake manifold 3a distributes and supplies the intake air sent from the intake pipe 3b to the intake ports of each cylinder. The intake pipe 3b is provided with an air cleaner 3c, a turbocharger 5 compressor 5C, and an intercooler 6 in this order from the upstream side.

The exhaust passage 4 is mainly defined by an exhaust manifold 4a connected to the engine body 2 (particularly the cylinder head) and an exhaust pipe 4b arranged on the downstream side of the exhaust manifold 4a. The exhaust manifold 4a collects the exhaust sent from the exhaust port of each cylinder. A turbine 5T of the turbocharger 5 is provided between the exhaust manifold 4a and the exhaust pipe 4b.

The head cover 10 is formed in a substantially rectangular shape that is long in the front-rear direction in a top view. Further, the head cover 10 has a frame portion 11 fixed to the upper portion of the cylinder head and a ceiling portion 12 integrally formed at the upper end portion of the frame portion 11.

Further, as shown by the broken line X, a first oil separator 100 for separating oil from the blow-by gas of the internal combustion engine 1 is provided inside the head cover 10. As is well known, blow-by gas is gas that leaks into the crankcase from the gap between the cylinder and the piston in the engine body 2.

An opening 13 is formed on the right front end of the ceiling 12. The downstream end of the upstream blow-by gas pipe 14 extending from the crankcase through the outside of the cylinder block is connected to the opening 13.

A second oil separator 200 is installed at the rear of the ceiling 12. Although details will be described later, the second oil separator 200 uses the compressed air generated by the compressor 5C to separate the oil remaining in the blow-by gas without being completely separated by the first oil separator 100. Reference numeral 40 is an air pipe for taking out compressed air from the intake pipe 3b and introducing it into the second oil separator 200, and reference numeral 50 is a downstream blow-by for releasing the blow-by gas after oil separation into the atmosphere. It is a gas pipe. However, the downstream blow-by gas pipe 50 may return the blow-by gas after the oil separation to the intake pipe 3b located between the air cleaner 3c and the compressor 5C.

Next, the configuration of the first oil separator 100 will be described with reference to FIGS. 2 to 9. In the figure, the reference numeral BO indicates the oil separated from the blow-by gas, and the reference numeral EO indicates the engine oil scattered from the valve operating mechanism.

As shown in FIGS. 2 and 3, the first oil separator 100 includes a baffle chamber 20 provided inside the head cover 10 as a blow-by gas passage. Further, the first oil separator 100 includes first to

third recesses

31, 32, 33 as recesses for storing the oil BO separated from the blow-by gas. The first oil separator 100 also includes an oil outlet D provided in each of the

recesses

31, 32, 33. Further, the first oil separator 100 includes a cover member C that covers the outlet of the oil discharge port D from below.

The baffle chamber 20 is formed in a substantially rectangular shape or an oval shape that is long in the front-rear direction in a top view. Further, the baffle chamber 20 includes a ceiling portion 12 of the head cover 10, a plurality of side wall portions 21 to 29 extending downward from the lower surface of the ceiling portion 12, and a bottom wall portion 30 connected to the lower ends of the side wall portions 21 to 29. Have.

A gas outlet 15 of the baffle chamber 20 is formed at the rear end of the ceiling 12. The gas outlet 15 discharges the blow-by gas after the oil is separated in the baffle chamber 20 into the second oil separator 200 (see FIG. 1).

For the bottom wall portion 30, a thin metal plate (for example, a thickness of 1 mm) formed separately from the side wall portions 21 to 29 is used. The bottom wall portion 30 is screwed and fixed to the lower ends of the side wall portions 21 to 29.

Also, the right end portion of the bottom wall portion 30 is provided with first to

third recesses

31, 32, 33. The bottom wall portion 30 is inclined downward toward the right side so that the oil separated from the blow-by gas flows down on the upper surface of the bottom wall portion 30 and is introduced into the

recesses

31, 32, 33. It is provided.

The side wall parts 21 to 29 are arranged separately from each other in order from the front so as to change the flow direction of the blow-by gas, the right side wall part 21, the left side wall part 22, the front side wall part 23, the rear side wall part 24. First to fifth baffle side wall parts 25 to 29 are included. The connection positions of these side wall portions 21 to 29 are as shown by the imaginary line Y in FIGS. 4 to 6.

The side wall portions 21 to 29 are formed integrally with the ceiling portion 12 of the head cover 10. The right side wall portion 21 is also formed integrally with the frame portion 11 of the head cover 10.

The right side wall 21 and the left side wall 22 are formed to extend in the front-rear direction. Further, the right side wall portion 23 has a first protrusion P1 and a second protrusion P2 as protrusions. That is, the right side wall portion 21 of the present embodiment corresponds to the first side wall portion in the claims.

As shown in FIGS. 2 and 4, the front side wall portion 23 is formed to extend in the left-right direction. The left and right ends of the front side wall 23 are connected to the front ends of the left and

right side walls

21, 22 respectively. The connecting portion between the front side wall portion 23 and the right side wall portion 21 has a gently curved cross-sectional shape.

A gas inlet 23a of the baffle chamber 20 is formed on the left side portion of the front side wall portion 23. The blow-by gas introduced into the head cover 10 from the opening 13 of the ceiling portion 12 is introduced into the baffle chamber 20 through the gas inlet 23a.

As shown in FIGS. 2 and 6, the rear side wall portion 24 is formed in a semicircular shape curved so as to be convex toward the rear in a plan view. The left and right end portions of the rear side wall portion 24 are connected to the rear end portions of the left and right

side wall portions

21 and 22, respectively. The connecting portion between the rear side wall portion 24 and the right side wall portion 21 and the connecting portion between the rear side wall portion 24 and the left side wall portion 22 each have a gently curved cross-sectional shape.

As shown in FIGS. 2 and 4 to 6, the first baffle side wall portion 25 is connected to the front portion of the left side wall portion 22, and the third baffle side wall portion 27 is an intermediate portion in the front-rear direction of the left side wall portion 22. The fifth baffle side wall portion 29 is connected to the rear portion of the left side wall portion 22.

The first, third, and fifth baffle

side wall portions

25, 27, and 29 each have a linear cross-sectional shape extending in the left-right direction. Further, the first, third and fifth baffle

side wall portions

25, 27, 29 are separated from the right side wall portion 21 in the left direction from the

base end portions

25a, 27a, 29a connected orthogonally to the left side wall portion 22. And the

distal end portions

25b, 27b, and 29b that are arranged in parallel.

The second baffle side wall portion 26 is connected to the right side wall portion 21 located between the first and third baffle

side wall portions

25 and 27 in the front-rear direction. Further, the fourth baffle side wall portion 28 is connected to the right side wall portion 21 located between the third and fifth baffle

side wall portions

27 and 29 in the front-rear direction.

Although the details will be described later, the second and fourth baffle

side wall portions

26 and 28 are bent to the left by colliding the blow-by gas flowing backward along the right side wall portion 21 as the first side wall portion, respectively. That is, the second and fourth baffle

side wall portions

26 and 28 correspond to the second side wall portion as defined in the claims. Further, the "backward" referred to here corresponds to the "first direction" in the claims.

The second and fourth baffle

side wall portions

26, 28 each have an L-shaped cross-sectional shape and are formed so as to extend leftward and gently bend forward. Further, the second and fourth baffle

side wall portions

26 and 28 have a

base end portion

26a and 28a connected orthogonally to the right side wall portion 21 and a tip portion arranged so as to be separated from the left wall portion 22 in the right direction. It has 26b and 28b, respectively. Further, the

tip portions

26b and 28b of the second and fourth baffle

side wall portions

26 and 28 are bent toward the front (that is, the upstream side in the first direction).

The first protruding portion P1 is located at a position separated from the second baffle side wall portion 26 forward. Further, the second protrusion P2 is located at a position behind the third baffle side wall portion 27 and at a position separated forward from the fourth baffle side wall portion 28. In the present embodiment, the protrusion is not arranged at a position behind the fourth baffle side wall portion 28, but it may be arranged.

Each protrusion P1 and P2 is formed in a triangular shape protruding to the left from the right wall portion 21 in a plan view. Further, each of the protrusions P1 and P2 has a front inclined surface Pa that is inclined in a direction (leftward) away from the right wall portion 21 as it goes rearward from its front end position. Further, each of the protrusions P1 and P2 has a rear inclined surface Pb that is inclined to the left from the rear end position toward the front. The front sloped surface Pa is more gently sloped than the rear sloped surface Pb. Further, the front inclined surface Pa is formed so as to swivel the blow-by gas clockwise in cooperation with the second and fourth baffle

side wall portions

26 and 28.

Although details will be described later, in the present embodiment, the above-mentioned side wall portions 21 to 29 and the protrusions P1 and P2 generate a winding blow-by gas flow that looks like an arrow over the entire inside of the baffle chamber 20. Then, in the process of the flow, the oil BO contained in the blow-by gas adheres to the wall surfaces of the ceiling portion 12, the side wall portions 21 to 29, and the bottom wall portion 30. As a result, the oil BO is separated from the blow-by gas.

As shown in FIGS. 3 to 6, the first to

third recesses

31, 32, and 33 store the oil BO separated from the blow-by gas and discharge the accumulated oil BO from the oil discharge port D. Composed.

Specifically, the first to

third recesses

31, 32, 33 are located at the connecting portions between the right side wall portion 21 and the bottom wall portion 30, respectively. Each

recess

31, 32, 33 is formed in a substantially rectangular shape that is long in the front-rear direction in a top view. Further, each of the

recesses

31, 32, 33 has a U-shaped cross-sectional shape in which the right end portion of the bottom wall portion 30 is recessed downward. Further, each of the

recesses

31, 32, 33 has an oil introduction port E at the upper end opening and an oil discharge port D at the bottom F.

Further, as will be described in detail later, each of the

recesses

31, 32, and 33 has a depth capable of generating stagnation of blow-by gas inside and suppressing the application of negative pressure of blow-by gas.

The oil discharge port D is formed by a circular hole and has a hole diameter large enough to discharge the accumulated oil BO by its own weight. Further, two oil discharge ports D are provided in the central portion of the bottom portions F of the

recesses

31, 32, and 33 at intervals in the front-rear direction. However, the position and number of the oil discharge ports D may be arbitrary, and may be one, for example.

Further, as shown in FIGS. 4 and 7, the first recess 31 is located at the connection portion between the right side wall portion 21 and the second baffle side wall portion 26. Specifically, the first recess 31 is located immediately in front of the base end portion 26a of the second baffle side wall portion 26.

Further, the first recess 31 is located in the baffle chamber 20 at a position behind the first protrusion P1 in the direction toward the rear. That is, the first recess 31 is arranged on the right side of the apex of the front inclined surface Pa so as to be hidden by the first protrusion P1 in the front view.

Further, the right side portion of the first recess 31 is arranged below the right side wall portion 21. That is, by arranging the right side portion of the first recess 31 so as to slip below the right wall portion 21, only the left portion of the oil introduction port E of the first recess 31 is opened in the baffle chamber 20.

As shown in FIGS. 5 and 8, the second recess 32 is located at the connecting portion between the right side wall portion 21 and the fourth baffle side wall portion 28. Specifically, the second recess 32 is located immediately in front of the base end portion 28a of the fourth baffle side wall portion 28.

Further, the second recess 32 is located in the baffle chamber 20 at a position behind the second protrusion P2 in the rearward direction. That is, the second recess 32 is arranged on the right side of the apex of the front inclined surface Pa so as to be hidden by the second protrusion P2 in the front view.

Further, the second recess 32 is located near the left side of the right side wall portion 21 and is not arranged below the right side wall portion 21. That is, in the present embodiment, the entire oil introduction port E of the second recess 32 is opened in the baffle chamber 20.

As shown in FIGS. 6 and 9, the third recess 33 is located at the connection portion between the right side wall portion 21 and the rear side wall portion 24. Specifically, the third recess 33 is located immediately in front of the right end of the rear sidewall 24.

Further, in the present embodiment, substantially the entire portion excluding the left end portion of the third recess 33 is arranged below the right side wall portion 21. That is, as can be seen by comparing FIGS. 4 and 6, the third recess 33 is arranged so as to sneak to the right side of the first wall 31 with respect to the right side wall 21. Therefore, in the third recess 33, only the left end portion having an area smaller than the oil introduction port E is opened in the baffle chamber 20.

As shown in FIGS. 7 to 9, as the cover member C, a plate-shaped member bent in a substantially crank shape from the left end to the right end is used.

The cover member C has a left end Ca extending parallel to the bottom wall 30 on the left side of the

recesses

31, 32, 33, an intermediate portion Cb extending diagonally downward to the right from the right end of the left end Ca, and an intermediate portion Cb. And a right end portion Cc extending horizontally from the right end to the right direction.

The left end Ca is welded and fixed to the lower surface of the bottom wall 30. Further, the right end Cc is spaced downward from the bottom F of each

recess

31, 32, 33 and is arranged so as to cover the entire lower surface of the bottom F from below.

Next, the configuration of the second oil separator 200 will be described with reference to FIGS. 1 and 10. Reference numeral J in FIG. 10 is a fastening member such as a metal band for detachably fastening the connecting portion between the pipes.

As shown in FIGS. 1 and 10, the second oil separator 200 is installed on the upper surface of the ceiling portion 12 of the head cover 10. The second oil separator 200 includes an oil separation unit 201 that introduces blow-by gas from the inside of the baffle chamber 20 through the gas outlet 15 and separates the oil remaining in the blow-by gas. Further, the oil separator 200 introduces the compressed air generated by the compressor 5C to generate a negative pressure, and the negative pressure sucks the blow-by gas after the oil BO is separated by the oil separation unit 201. The unit 202 is provided.

The oil separating unit 201 includes a lower casing 201a connected to the ceiling 12 of the head cover 10 and an upper casing 201b connected to the upper surface of the lower casing 201a.

The lower casing 201a communicates with the baffle chamber 20 and the upper casing 201b. The upper casing 201b is configured to collide the blow-by gas introduced from the lower casing 201a with the wall to separate the oil from the blow-by gas.

The gas suction part 202 is formed in a tubular shape extending in the left-right direction and is supported on the upper casing 201b. Further, the gas suction unit 202 blows out the introduced compressed air from the orifice, and sucks blow-by gas from the upper casing 201b by the negative pressure generated by the ejection.

At the upstream end of the gas suction unit 202, an introduction unit 202a for introducing compressed air from the air pipe 40 is provided. The introduction part 202a is formed in a tubular shape, and is fitted and connected to the downstream end of the air tube 40. On the other hand, as shown in FIG. 1, the upstream end of the air pipe 40 is connected to the intake pipe 3b on the downstream side of the intercooler 6.

On the other hand, the downstream end of the gas suction part 202 is connected to the upstream end of the downstream blow-by gas pipe 50 via a resin hose member H.

In the second oil separator 200, blow-by gas is sucked from the upper casing 201b of the oil separation section 201 by the negative pressure generated by the compressed air flowing through the gas suction section 202, and the sucked blow-by gas is sucked together with the compressed air on the downstream side blow-by. Discharge from the gas pipe 50. In this way, the suction of blow-by gas causes a flow of blow-by gas that looks like an arrow.

Specifically, the blow-by gas introduced from the baffle chamber 20 through the lower casing 201a into the upper casing 201b collides with the wall of the upper casing 201b. As a result, the oil contained in the blow-by gas adheres to the wall of the upper casing 201b, and the oil is separated from the blow-by gas.

The blow-by gas after oil separation is sucked into the gas suction unit 202 from the upper casing 201b and discharged from the downstream blow-by gas pipe 50 together with the compressed air. Further, the oil separated from the blow-by gas is returned to the inside of the crankcase through the inside of the head cover 10.

Next, the function and effect of the first oil separator 100 according to this embodiment will be described.

As shown in FIG. 4, the blow-by gas introduced from the gas inlet 23a of the baffle chamber 20 collides with the first baffle side wall portion 25 and is bent to the right, and then collides with the right wall portion 21 and rearward. It is bent and flows backward along the right wall portion 21.

The blow-by gas that has flowed backward along the right side wall portion 21 is guided diagonally rearward to the left along the front inclined surface Pa of the first protrusion P1 and collides with the second baffle side wall portion 26 to the left. Can be bent. Further, the blow-by gas is bent forward along the tip portion 26b of the second baffle side wall portion 26 and swivels clockwise, and at the same time, the tip portion 26b of the second baffle side wall portion 26 and the first baffle side wall portion 25 It flows to the left through the space. Then, the blow-by gas collides with the left side wall portion 22 and is bent rearward, and then flows rearward along the left side wall portion 22.

The subsequent flow of blow-by gas in the baffle chamber 20 is substantially a repetition of the flow of blow-by gas described in FIG.

That is, as shown in FIG. 5, the blow-by gas flowing rearward along the left side wall portion 22 collides with the third baffle side wall portion 27, is bent to the right, and then collides with the right side wall portion 21. It is bent rearward and flows rearward along the right side wall portion 21.

The blow-by gas that has flowed backward along the right side wall portion 21 is guided diagonally rearward to the left along the front inclined surface Pa of the second protrusion P2, and collides with the fourth baffle side wall portion 28 to the left. Can be bent. Further, the blow-by gas is bent forward along the tip 28b of the fourth baffle side wall 28 and swivels clockwise, and at the same time, the tip 28b of the fourth baffle side wall 28 and the third baffle side wall 27 It flows to the left through the space. Then, the blow-by gas collides with the left side wall portion 22 and is bent rearward, and then flows rearward along the left side wall portion 22.

As shown in FIG. 6, the blow-by gas flowing rearward along the left side wall portion 22 collides with the fifth baffle side wall portion 29 and is bent to the right, and then collides with the right side wall portion 21 and rearwardly. It is bent and flows backward along the right wall portion 21.

The blow-by gas that flows backward along the right wall portion 21 is folded back from the rear to the front along the rear side wall portion 24, turns clockwise, and then is discharged from the gas outlet 15 of the ceiling portion 12.

In the present embodiment, the oil BO contained in the blow-by gas is separated by the collision, bending, turning, etc. of the blow-by gas as described above, and adheres to the wall surfaces of the ceiling portion 12, the side wall portions 21 to 29, and the bottom wall portion 30. .. As a result, the oil BO is separated from the blow-by gas.

Further, the oil BO separated from the blow-by gas is collected on the bottom wall portion 30, flows down on the upper surface of the bottom wall portion 30, and then is introduced into the first to

third recesses

31, 32, 33 and stored. To be

Here, although not shown, in a general baffle chamber, a recess for storing oil is not provided, for example, an oil discharge port is directly formed on the bottom wall portion. Therefore, the negative pressure generated by the blow-by gas flowing in the baffle chamber may cause the oil to be discharged from the oil discharge port to be sucked into the baffle chamber. As a result, the oil may not be smoothly discharged from the oil discharge port, substantial oil separation may be hindered, and the oil may be discharged from the gas outlet of the baffle chamber.

On the other hand, in the baffle chamber 20 of the present embodiment, for example, as shown in FIGS. 4 and 7, a first recess 31 is provided in the bottom wall portion 30, and an oil discharge port D is provided in the first recess 31. It is formed. Therefore, the stagnation of the blow-by gas is generated inside the first recess 31, so that the negative pressure of the blow-by gas can be suppressed. Further, the oil BO separated from the blow-by gas can be hardly sucked against the negative pressure of the blow-by gas by being stored and collected in the first recess 31. As a result, the oil BO stored in the first recess 31 can be smoothly discharged from the oil discharge port D by its own weight.

Therefore, according to the first recess 31, the oil BO is suppressed from being sucked by the negative pressure of the blow-by gas, and the oil BO separated from the blow-by gas can be smoothly discharged from the oil discharge port D. Then, the oil BO can be suppressed from being discharged from the gas outlet 15 of the baffle chamber 20.

The same effect as that of the first recess 31 can be produced in the second and third recesses 32 and 33 (see FIGS. 5, 6, 8 and 9).

Further, the first recess 31 of the present embodiment is located at an orthogonal connection portion between the right side wall portion 21 and the second baffle side wall portion 26. At such a corner position, it becomes difficult for blow-by gas to flow, and stagnation of blow-by gas tends to occur. Therefore, the negative pressure of blow-by gas can be effectively suppressed from being applied to the first recess 31.

Since the second recess 32 is also located at the connecting portion where the right side wall portion 21 and the fourth baffle side wall portion 28 are orthogonal to each other, the same effect as this can occur (see FIGS. 5 and 8).

Further, in the present embodiment, the first recess 31 is located behind the first protrusion P1. That is, the blow-by gas that is about to flow toward the first recess 31 along the right wall portion 21 can be blocked by the first protrusion P1. As a result, the stagnation of the blow-by gas can be easily generated at the position of the first recess 31, so that the negative pressure of the blow-by gas can be effectively suppressed from being applied to the first recess 31.

The same effect can be produced by the second protrusion P2 on the second recess 32 (see FIGS. 5 and 8).

Further, in the present embodiment, the blow-by gas can be swirled by the inclined surface Pa of the first protrusion P1 and the second baffle side wall portion 26. As a result, the residence time of the blow-by gas in the baffle chamber 20 can be lengthened, and the centrifugal force generated by the swirling of the blow-by gas can also be used to effectively separate the oil BO.

The same effect can be produced in the combination of the second protrusion P2 and the fourth baffle side wall 28 and the rear side wall 24 (see FIGS. 5 and 6).

Further, the right side portion of the first recess 31 is arranged below the right side wall portion 21. As a result, the oil introduction port E of the first recess 31 is closed and narrowed by the lower end of the right side wall 21. As a result, blow-by gas does not easily flow in and out between the inside of the baffle chamber 20 and the inside of the first recess 31, so that stagnation of the blow-by gas can easily occur inside the first recess 31.

On the other hand, as can be seen by comparing FIGS. 4 and 6, the area of the oil inlet E opened in the baffle chamber 20 of the third recess 33 is smaller than that of the first recess 31. Therefore, if the third recess 33 is used, it is possible to reliably generate stagnation of the blow-by gas without blocking the blow-by gas by the protrusion.

On the other hand, as shown in FIGS. 7 to 9, engine oil EO is scattered upward from the valve operating mechanism (not shown) toward the bottom wall portion 30 of the baffle chamber 20 in the head cover 10. Therefore, the oil BO that is about to be discharged from the oil discharge port D may be pushed back by the scattered engine oil EO.

However, in the present embodiment, the cover member C covers the outlet of the oil outlet D, so that the oil outlet D can be shielded from the engine oil EO scattered in the head cover 10. Therefore, it is possible to reliably prevent the oil BO that is about to be discharged from the oil discharge port D from being pushed back by the engine oil EO.

On the other hand, the embodiment described above can be modified as follows or a combination thereof. In the following description, the same reference numerals are used for the same components as those in the above embodiment, and detailed description thereof will be omitted.

(First modification)
Although the first and

third recesses

31 and 33 of the above-described embodiment are partially disposed below the right side wall 21, the entire recess may be disposed below the right side wall.

For example, as shown in FIG. 11, in the first modification, the entire first recess 31 is arranged so as to sneak below the right wall portion 21. Further, a vertical gap S is formed between the lower end of the right side wall portion 21 and the upper surface of the bottom wall portion 30, and oil is introduced from the inside of the baffle chamber 20 into the first concave portion 31 through this gap S. To be done.

(Second modified example)
The side walls 21 to 29 may have any shape as long as they can be bent by colliding blow-by gas.

For example, as shown in FIG. 12, the second and fourth baffle

side wall portions

26 and 28 of the second modification have extending

portions

26c and 28c extending to the right from the front ends of the

tip portions

26b and 28b, respectively. Have.

On the contrary, at least one of the second and fourth baffle

side wall portions

26, 28 does not need to be bent forward.

(Third Modification)
Although the side walls 21 to 29 of the above-described embodiment are formed integrally with the head cover 10, the side walls 21 to 29 may be formed separately from the head cover 10 by a metal plate or the like.

Further, in the third modification, for example, the

tip portions

26b and 28b and the other portions may be separately formed in the second and fourth baffle

side wall portions

26 and 28.

(Fourth modification)
The second and fourth baffle

side wall portions

26 and 28 may be connected to intersect with the right side wall portion 21 and may not necessarily be connected to each other at right angles. Similarly, the first, third, and fifth baffle

side wall portions

25, 27, 29 may also be connected to intersect with the left side wall portion 22 and may not necessarily be connected orthogonally.

(Fifth Modification)
The recess may be partially disposed behind the protrusion. For example, in the second recess 32 of the fifth modified example, only the right side portion thereof is arranged so as to be hidden by the protrusion in front view, and the left side portion thereof is arranged on the left side of the protrusion.

(Sixth Modification)
The recess is not limited to a U-shaped cross section. For example, the first concave portion of the sixth modified example has a semicircular cross-sectional shape that is curved so as to be convex downward.

(Seventh modification)
Any one or two of the first to

third recesses

31, 32, 33 may be omitted. For example, in the seventh modified example, the second recess 32 is omitted, and the oil outlet D is directly formed in the bottom wall of the baffle chamber.

(8th modification)
The protrusion may have any shape as long as it can block the blow-by gas that tends to flow toward the recess.

For example, the first protrusion P1 of the eighth modification is formed in a semicircular shape or a U shape curved so as to be convex toward the left in a plan view.

Further, for example, the second protrusion P2 of the eighth modified example has a vertical surface that extends vertically from the right side wall portion 21 to the left instead of the rear side inclined surface Pb.

(9th modification)
At least one of the first and second protrusions P1 and P2 may be omitted.

Although the embodiments of the present disclosure have been described above in detail, the embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications and applications included in the concept of the present disclosure defined by the claims. Examples, equivalents are included in this disclosure. Therefore, the present disclosure should not be limitedly interpreted, and can be applied to any other technique belonging to the scope of the idea of the present disclosure.

This application is based on the Japanese patent application filed on March 6, 2019 (Japanese Patent Application No. 2019-040624), the contents of which are incorporated herein by reference.

1 Internal Combustion Engine 10 Head Cover 12 Ceiling 20 Baffle Chamber (Blow-by Gas Passage)
21 Right Side Wall (First Side Wall)
22 Left side wall part 23 Front side wall part 24 Rear side wall part 25 First baffle side wall part 26 Second baffle side wall part (second side wall part)
27 Third Baffle Side Wall 28 Fourth Baffle Side Wall (Second Side Wall)
29 Fifth baffle side wall 30 Bottom wall 31 First recess 32 Second recess 33 Third recess 100 First oil separator (oil separator)
200 Second oil separator 201 Oil separating part 202 Gas suction part A Intake air, compressed air B Blow-by gas BO Oil C separated from blow-by gas C Cover member D Oil outlet EO Engine oil G scattered from valve operating mechanism G Exhaust P1 1 protrusion P2 2nd protrusion

Claims

An oil separator for separating oil from blow-by gas of an internal combustion engine.
A blow-by gas passage provided inside the head cover of the internal combustion engine and having a bottom wall portion,
A recess provided in the bottom wall for storing oil separated from blow-by gas, and
An oil discharge port provided in the recess and configured to discharge the oil accumulated in the recess.
The blow-by gas passage has a first side wall portion and a second side wall portion that intersects and is connected to the first side wall portion, and that causes the blow-by gas flowing along the first side wall portion to collide and bend. ,
The oil separator according to claim 1, wherein the concave portion is located at a connection portion of the first and second side wall portions.
The first side wall portion has a protrusion and has a protrusion.
The protrusion is located at a position separated from the second side wall to the upstream side in a first direction that is a flow direction of blow-by gas along the first side wall,
The oil separator according to claim 2, wherein the recess is located at a position behind the protrusion in the first direction.
The oil separator according to claim 3, wherein the protruding portion has an inclined surface that is inclined in a direction away from the first side wall portion toward the first direction.
The oil separator according to claim 4, wherein the second side wall portion has a base end portion that is connected to intersect with the first side wall portion and a distal end portion that is bent toward the upstream side in the first direction. ..
The concave portion is located at a connecting portion between the first side wall portion and the bottom wall portion,
The oil separator according to any one of claims 2 to 5, wherein the recess is arranged below the first side wall portion.
The oil separator according to claim 1, further comprising a cover member that covers the outlet of the oil discharge port from below.