JP7371518B2 - Oil separation structure - Google Patents

Description

The technology disclosed herein belongs to the technical field related to oil separation structures.

Conventionally, oil separation structures for separating oil from blow-by gas generated within an engine have been known.

For example, Patent Document 1 discloses an oil mist separator in which a plurality of oil separation sections for separating oil in blowby gas are arranged in series in the flow direction of blowby gas in a housing provided separately from the main body of the engine. ing.

Japanese Patent Application Publication No. 2018-66319

The inventors of the present application conducted extensive research and found that when pressure fluctuations occur in the oil recovery chamber that collects the oil separated in the oil separation section, the oil blows back from the drain oil passage that collects the oil. Do you get it. It was also found that the blown back oil adhered to the wall of the oil recovery chamber and was then swept away to the next chamber by the blow-by gas flow.

When a plurality of oil separation sections are provided like the oil separation structure described in Patent Document 1, the oil recovery efficiency may be improved compared to the case where there is only one oil separation section. However, in a structure in which a plurality of oil separation sections are simply provided, all of the blown back oil is collected in the next chamber. If the amount of oil to be recovered in the next chamber increases, the oil will be blown back again, making it impossible to expect an improvement in oil recovery efficiency.

The technology disclosed herein improves oil recovery efficiency in an oil separation structure having a plurality of oil separation sections.

In order to solve the above problem, the technology disclosed herein targets an oil separation structure for separating oil from blow-by gas generated in an engine, and provides a housing having an oil separator chamber for separating the oil. a first oil separation section that is disposed in the oil separator chamber and is located relatively upstream in the flow direction of the blow-by gas; a second oil separation section located on the downstream side of the direction; and a drain provided in an oil recovery chamber between the first oil separation section and the second oil separation section, and having a drain port into which the separated oil flows. an oil passage, and the second oil separation section includes a ventilation port through which the blow-by gas passes after passing through the first oil separation section; a protruding wall that is provided around the ventilation port so as to surround the ventilation hole and protrudes from the end face on the oil recovery chamber side toward the upstream side in the flow direction , and the protruding wall is arranged around the first oil separation section. and the second oil separation section, the second oil separation section is provided only in the second oil separation section .

According to this configuration, even if oil adhering to the wall of the oil recovery chamber (hereinafter referred to as residual oil) is swept downstream along the wall by the blow-by gas airflow, the protruding wall prevents the residual oil from penetrating into the ventilation opening. It is restrained from doing so. Further, the remaining oil flows down to the bottom of the oil recovery chamber along the protruding wall, and then flows into the drain port. This suppresses oil adhering to the wall surface of the oil recovery chamber from flowing into a chamber on the downstream side of the oil recovery chamber. As a result, oil recovery efficiency can be improved.

In the oil separation structure, the second oil separation section includes an oil separator having the ventilation hole and the protruding wall, and the oil separator is arranged in a space downstream of the second oil separation section in the flow direction. and the oil recovery chamber, and the ventilation port may be located at the center of the partition wall when viewed from the upstream side in the flow direction.

According to this configuration, the ventilation port of the second oil separation section is located at a position sufficiently distant from each wall that partitions the oil recovery chamber, so that the remaining oil flowing downstream along each wall surface is can be appropriately blocked by a protruding wall. Thereby, oil recovery efficiency can be further improved.

In one embodiment of the oil separation structure, the protruding wall has a cylindrical shape surrounding the ventilation hole when viewed from the upstream side in the flow direction.

According to this configuration, it is possible to effectively suppress residual oil from flowing into the ventilation port of the second oil separation section. Thereby, oil recovery efficiency can be further improved.

In the above embodiment, the protruding wall may have a tapered shape in which the diameter increases toward the upstream side in the flow direction.

According to this configuration, it is possible to more effectively suppress residual oil from flowing into the ventilation port of the second oil separation section. Further, residual oil tends to accumulate in the area between the partition wall and the protruding wall. This increases the size of the remaining oil droplets, making it easier for the remaining oil to move toward the bottom surface. As a result, oil recovery efficiency can be further improved.

The drain port may be provided upstream of the center of the oil recovery chamber in the flow direction.

According to this configuration, the oil separated by the first oil separation section can be efficiently recovered. Further, by separating the drain port from the second oil separation section, it is possible to suppress oil blown back from the drain port from directly entering the ventilation port of the second oil separation section. Thereby, oil recovery efficiency can be further improved.

In the oil separation structure, the bottom portion of the oil recovery chamber may have an inclined portion that slopes toward the drain port from a position where the second oil separation portion is provided.

According to this configuration, the remaining oil that has fallen to the bottom part can easily flow toward the drain port. Thereby, oil recovery efficiency can be further improved.

As described above, according to the technology disclosed herein, oil recovery efficiency can be improved in an oil separation structure having a plurality of oil separation sections.

1 is a sectional view of an engine to which an oil separation structure according to an exemplary embodiment is applied. FIG. 3 is a perspective view showing a head cover portion of the engine. FIG. 3 is a sectional view taken along line III-III in FIG. 2, and includes a cylinder head and a part of the cylinder block. 3 is a cross-sectional view taken along line VII-VII in FIG. 2. FIG. FIG. 3 is a diagram of the first oil separator of the first oil separation section viewed from the upstream side. FIG. 3 is a diagram of a second oil separator of the second oil separation section viewed from the upstream side. FIG. 4 is an enlarged sectional view showing the second oil separation section in FIG. 3 in an enlarged manner. FIG. 7 is a diagram showing how oil accumulates in the area between the protruding wall and the second partition wall. It is a figure which shows the 1st modification of a 2nd oil separator, Comprising: The left figure is a figure which looked at the 2nd oil separator from the upstream side, and the right figure is a sectional view taken along the AA line of the left figure. . It is a figure which shows the 2nd modification of a 2nd oil separator, Comprising: The left figure is a figure which looked at the 2nd oil separator from the upstream side, and the right figure is a sectional view taken along the AA line of the left figure. .

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. In the following description, the front, rear, left, right, top, and bottom of the vehicle will be simply referred to as front, rear, left, right, top, and bottom, respectively.

FIG. 1 shows a schematic configuration of an engine 1 to which a cylinder head cover structure according to Embodiment 1 of the present invention is applied. In this embodiment, the engine 1 is a 6-cylinder in-line engine that is vertically mounted in the engine room at the front of the vehicle so that the crankshaft 9 extends in the longitudinal direction (perpendicular to the plane of FIG. 1). be. The engine 1 may be a diesel engine or a gasoline engine.

The engine 1 includes a cylinder block 3 in which six cylinders 2 (only one is shown in FIG. 1) are arranged in a row in the axial direction of a crankshaft 9, and cylinders arranged on the cylinder block 3. It has a head 4 and a cylinder head cover 5 that covers the upper side of the cylinder head 4. A piston 8 is fitted into each cylinder 2 so as to be able to reciprocate. The piston 8 of each cylinder 2 is connected to a crankshaft 9 via a connecting rod (not shown).

Although not shown, the cylinder head 4 is formed with an intake port and an exhaust port for each cylinder 2, as well as an intake valve and an exhaust valve that open and close the openings of these intake ports and exhaust ports on the combustion chamber 10 side. A valve is provided for each. In this embodiment, the intake port is located on the left side and the exhaust port is located on the right side.

From the top of the cylinder head 4 to the bottom of the cylinder head cover 5, there is an intake camshaft 11 equipped with a cam that opens and closes the intake valves of all cylinders 2, and a cam that opens and closes the exhaust valves of all cylinders 2. A provided exhaust camshaft 12 is arranged to extend in the axial direction of the crankshaft 9. Although not shown in the drawings, oil as lubricating oil is supplied to bearings that rotatably support the intake camshaft 11 and the exhaust camshaft 12, respectively. Further, oil is dripped and supplied to the cams of the intake camshaft 11 and the exhaust camshaft 12 by an oil shower disposed above them.

Further, the cylinder head 4 is provided with an injector 18 for injecting fuel for each cylinder 2. This injector 18 is arranged so that the fuel injection port of the injector 18 faces the combustion chamber 10 from the ceiling surface of the combustion chamber 10, and directly injects fuel into the combustion chamber 10 near the top dead center of the compression stroke. It is supposed to be done.

An intake passage 21 is connected to the vehicle front surface of the cylinder head 4 so as to communicate with the intake port of each cylinder 2 . This intake passage 21 is provided with an air cleaner 22, and the intake air from which dust and the like have been removed by the air cleaner 22 is supplied to the combustion chamber 10 through the intake passage 21. A downstream portion of the intake passage 21 is constituted by an intake manifold 26, and is an independent passage branching for each cylinder 2. The downstream end of each independent passage is connected to the intake port of each cylinder 2, respectively. Although not shown, a throttle valve, a supercharger, and the like are arranged between the air cleaner 22 and the intake manifold 26 in the intake passage 21.

Although not shown, an exhaust passage for discharging exhaust gas from the combustion chamber 10 of each cylinder 2 is connected to a surface of the cylinder head 4 on the vehicle rear side. The upstream portion of the exhaust passage is constituted by an exhaust manifold having independent passages branched for each cylinder and connected to the exhaust port, and a gathering portion where the independent passages come together.

The cylinder head cover 5 is formed into a bottomed cylindrical shape with the upper side closed and the lower side open, and is fixed to the upper end of the cylinder head 4 to cover the upper sides of the intake camshaft 11 and the exhaust camshaft 12. The cylinder head cover 5 is made of resin or the like. The cylinder head cover 5 is fixed to the cylinder head 4 with a plurality of bolts B.

As shown in FIG. 2, the cylinder head cover 5 has plug holes 51 corresponding to the number of cylinders 2 (six in this embodiment). Spark plugs (not shown) are inserted into the plug holes 51, respectively.

The cylinder head cover 5 has an oil separator chamber 30 on the intake side of the plug hole 51 for separating and removing oil mist in the blow-by gas. As shown in FIG. 3, this oil separator chamber 30 is formed to be separated from a cam chamber 41 in which the intake camshaft 11 and the exhaust camshaft 12 are disposed. A breather hose 42 is connected to the outlet 39 of the oil separator chamber 30. The blow-by gas from which oil mist has been separated and removed in the oil separator chamber 30 flows into the intake system of the engine 1 through the breather hose 42 . The cylinder head cover 5 corresponds to a housing having an oil separator chamber 30.

The configuration of the oil separator chamber 30 will be described in detail below. In this embodiment, the upstream side of the blow-by gas in the flow direction is simply referred to as the upstream side, and the downstream side of the blow-by gas in the flow direction is sometimes simply referred to as the downstream side.

In this embodiment, as shown in FIG. 3, the oil separator chamber 30 is separated from a cam chamber 41 by a lower wall portion 31. The oil separator chamber 30 is formed by a ceiling part 32 that vertically faces a lower wall part 31, and a side wall part 33 that vertically connects the peripheral edge of the lower wall part 31 and the peripheral edge of the ceiling part 32. Inside the oil separator chamber 30, there is a first oil separation section 60 located relatively upstream in the flow direction of the blow-by gas, and a second oil separation section 60 located downstream of the first oil separation section 60 in the flow direction. Two oil separation sections, an oil separation section 70, are provided. The first oil separation section 60 and the second oil separation section 70 are arranged in series. The inside of the oil separator chamber 30 is divided into a gas inflow chamber 34, a first oil recovery chamber 35, and a second oil recovery chamber 36 from the upstream side in the flow direction by a first oil separation section 60 and a second oil separation section 70. It is divided into.

As shown in FIG. 4, the first oil recovery chamber 35 communicates with a first drain oil passage 37 having a first drain port 37a into which the oil separated by the first oil separation section 60 flows. The first drain port 37a is provided in the lower wall portion 31. The first drain port 37a is provided closer to the first oil separation section 60 than the second oil separation section 70 in the flow direction. The first drain oil passage 37 is composed of a pipe and a hole bored in the walls of the cylinder head 4 and cylinder block 3. The other end of the first drain oil passage 37 communicates with an oil pan (not shown) of the engine 1 . The bottom surface portion 35a of the first oil recovery chamber 35 has an inclined portion 35b that slopes downward (that is, toward the cylinder head 4 side) from the position where the second oil separation portion 70 is provided toward the first drain port 37a.

As shown in FIG. 4, the second oil recovery chamber 36 communicates with a second drain oil passage 38 having a second drain port 38a into which the oil separated by the second oil separation section 70 flows. The second drain port 38a is provided in the lower wall portion 31. The second drain port 38a is provided closer to the second oil separation section 70 than the outlet 39 in the flow direction. The second drain oil passage 38 is composed of a pipe and a hole bored in the walls of the cylinder head 4 and cylinder block 3. The other end of the second drain oil passage 38 communicates with the oil pan of the engine 1 . The bottom surface portion 36a of the second oil recovery chamber 36 is located below the bottom surface portion 35a of the first oil recovery chamber 35. The bottom surface portion 36a of the second oil recovery chamber 36 has an inclined portion 35b that slopes downward from the position where the downstream side wall portion 33 is provided toward the second drain port 38a. The blow-by gas that has passed through the second oil recovery chamber 36 flows into the breather hose 42 through the outlet 39. Thereafter, the blow-by gas flows into the intake system of the engine 1 through the breather hose 42.

As shown in FIGS. 4 and 5, the first oil separation section 60 is a first section extending from the ceiling section 32 and the left and right side walls 33 to partition the gas inflow chamber 34 and the first oil recovery chamber 35. It has a wall 61 and a first oil separator 62 fitted into the first partition wall 61. The first oil separator 62 is an impactor filter type separator. The first oil separator 62 includes a first main body portion 63 , a first ventilation port 64 formed through the first main body portion 63 and through which blow-by gas passes, and a first oil separator 62 arranged downstream of the first ventilation port 64 . It has a first filter 65 and a first filter support part 66 that supports the first filter 65.

The first partition wall 61 is provided with a groove portion 61a. The first oil separator 62 is attached to the first partition wall 61 by engaging the peripheral edge of the first main body portion 63 with this groove portion 61a. As shown in FIG. 5, a first guide portion 67 that protrudes toward the upstream side is provided on the upstream side surface of the first main body portion 63. As shown in FIG. The first guide portions 67 are provided in the upper portion and both left and right portions of the first main body portion 63, respectively. The first guide portion 67 is a portion that serves as a guide for attaching the first oil separator 62 to the first partition wall 61. When the first oil separator 62 is fitted into the first partition wall 61, the tip of the first guide portion 67 is flush with the upstream surface of the first partition wall 61, or Located downstream from the surface.

The first ventilation port 64 is located at a position slightly offset downward from the center of the first partition wall 61 when viewed from the upstream side.

The first filter support section 66 is attached to the rear side of the first main body section 63. The first filter 65 is attached to a first filter support portion 66 slightly downstream of the first partition wall 61 . The area of the first filter 65 is larger than the vertical cross-sectional area of the first ventilation port 64. The first filter 65 is arranged so that the end of the first filter 65 is not visible when looking into the first ventilation port 64 from the upstream side. The first filter 65 is made of nonwoven fabric, woven fabric, or the like.

The blow-by gas that has passed through the first ventilation port 64 collides with the first filter 65 . Due to this collision, the oil miss in the blow-by gas is captured by the first filter 65 and separated from the blow-by gas. The oil mist captured by the first filter 65 is dripped onto the bottom portion 35a of the first oil recovery chamber 35. Then, it flows into the first drain oil passage 37 from the first drain port 37a.

As shown in FIGS. 4, 6, and 7, the second oil separation section 70 includes a ceiling section 32 and left and right side walls to partition the first oil recovery chamber 35 and the second oil recovery chamber 36. 33, and a second oil separator 72 fitted into the second partition wall 71. The second oil separator 72 is an impactor filter type separator. The second oil separator 72 includes a second body portion 73, a second ventilation port 74 that is formed to penetrate the second body portion 73, and through which blow-by gas passes after passing through the first oil separation portion 60; It has a second filter 75 arranged downstream of the two ventilation ports 74 and a second filter support part 77 that supports the second filter 75.

As shown in FIG. 7, the second partition wall 71 is provided with a groove 71a. The second oil separator 72 is attached to the second partition wall 71 by engaging the peripheral edge of the second main body 73 with this groove 71a. A second guide portion 78 that protrudes toward the upstream side is provided on the upstream side surface of the second main body portion 73. The second guide portions 78 are provided at the upper portion and the left and right side portions of the second main body portion 73, respectively. The second guide portion 78 is a portion that serves as a guide for attaching the second oil separator 72 to the second partition wall 71. When the second oil separator 72 is fitted into the second partition wall 71, the tip of the second guide portion 78 is flush with the upstream surface of the second partition wall 71, or Located downstream from the surface.

Further, the second main body portion 73 is provided with a projecting wall 76 that is provided around the second ventilation port 74 and projects upstream from the end surface on the first oil recovery chamber 35 side when viewed from the upstream side. . As shown in FIG. 6, the protruding wall 76 has a cylindrical shape surrounding the second ventilation opening 74. As shown in FIG. More specifically, as shown in FIG. 7, the protruding wall 76 has a tapered shape whose diameter increases toward the upstream side. The tip of the protruding wall 76 is located upstream of the upstream surface of the second partition wall 71. As will be described in detail later, the protruding wall 76 is for suppressing oil that has moved along the ceiling portion 32, the side wall portion 33, and the second partition wall 71 from flowing into the second ventilation port 74. be.

The second ventilation port 74 is located at the center of the second partition wall 71 when viewed from the upstream side.

As shown in FIG. 7, the second filter support section 77 is attached to the rear side of the second main body section 73. The second filter support portion 77 includes a plurality of struts 77a extending downstream from the attachment portion to the second main body portion 73, and a filter attachment portion 77b attached to the downstream end of the struts 77a. The filter attachment portion 77b is located slightly downstream of the second partition wall 71. The filter attachment part 77b has a through hole 77c in the center. The through hole 77c is a hole through which blow-by gas after oil is captured by the second filter 75 passes.

The second filter 75 is attached to the upstream side surface of the filter attachment portion 77b, slightly downstream of the second partition wall 71. The area of the second filter 75 is larger than the vertical cross-sectional area of the second ventilation port 74. The second filter 75 is arranged so that the end of the second filter 75 is not visible when looking into the second ventilation port 74 from the upstream side. The second filter 75 is made of nonwoven fabric, woven fabric, or the like.

The blow-by gas that has passed through the second ventilation port 74 collides with the second filter 75. Due to this collision, the oil mist remaining in the blow-by gas that has passed through the first oil separation section 60 is captured by the second filter 75 and separated from the blow-by gas. The oil mist captured by the second filter 75 is dripped onto the bottom surface 36a of the second oil recovery chamber 36. Then, it flows into the second drain oil passage 38 from the second drain port 38a.

Here, as a result of intensive research by the inventors of the present application, it has been found that when the rotational speed of the engine 1 increases and the flow velocity of the blow-by gas increases, pressure fluctuations occur in the first oil recovery chamber 35. It was found that the oil was blown back from the passage 37. The blown back oil adheres to the ceiling part 32 and side wall part 33 of the first oil recovery chamber 35, and is then swept away toward the second oil recovery chamber 36 by the blow-by gas airflow. When the amount of oil to be recovered in the second oil recovery chamber 36 increases, the oil also comes to be blown back in the second drain oil passage 38, resulting in poor oil recovery efficiency.

In contrast, in the present embodiment, by providing the protruding wall 76 on the second oil separator 72 of the second oil separation section 70, the oil (hereinafter referred to as (referred to as residual oil) is suppressed from flowing into the second oil recovery chamber 36. That is, for example, as shown in FIG. 8, the residual oil adhering to the ceiling 32 of the first oil recovery chamber 35 is swept downstream along the ceiling 32 by the airflow of blow-by gas, and then the residual oil adheres to the ceiling 32 of the first oil recovery chamber 35 is swept downstream along the ceiling 32 by the blow-by gas airflow, and then the remaining oil adheres to the ceiling 32 of the first oil recovery chamber 35 is swept downstream along the ceiling 32 by the blow-by gas airflow. 71 and move downward. Since the protruding wall 76 extends upstream from the second partition wall 71, residual oil adheres to the protruding wall 76. The remaining oil adhering to the protruding wall 76 moves toward the base of the protruding wall 76 along the tapered surface of the protruding wall 76 . Thereafter, the remaining oil accumulated near the base of the protruding wall 76 moves downward along the protruding wall 76 due to its own weight. Then, after flowing down to the bottom surface 35a of the first oil recovery chamber 35, it flows along the inclined surface 36b and flows into the first drain port 37a. This prevents the remaining oil adhering to the walls of the ceiling 32 and side wall 33 of the first oil recovery chamber 35 from passing through the second oil separator 72 and flowing into the second oil recovery chamber 36 . As a result, oil recovery efficiency can be improved.

In particular, in this embodiment, the protruding wall 76 has a tapered shape in which the diameter increases toward the upstream side, so that the remaining oil is deposited in the area between the second partition wall 71 and the protruding wall 76. It becomes easy to accumulate. This increases the size of the remaining oil droplets, making it easier for the remaining oil to move toward the bottom portion 36a. As a result, oil recovery efficiency can be further improved.

Further, in this embodiment, the tip of the protruding wall 76 is located upstream of the upstream surface of the second partition wall 71. Thereby, it is possible to more effectively suppress the remaining oil that has passed through the second partition wall 71 from flowing into the second ventilation port 74 of the second oil separation section 70 .

Further, in this embodiment, the protruding wall 76 has a cylindrical shape surrounding the second ventilation port 74 when viewed from the upstream side. Thereby, it is possible to more effectively suppress remaining oil from flowing into the second ventilation port 74 of the second oil separation section 70. As a result, oil recovery efficiency can be further improved.

Further, in this embodiment, the second ventilation port 74 is located at the center of the second partition wall 71 when viewed from the upstream side. As a result, the second ventilation port 74 is located at a position sufficiently away from the ceiling 32, the lower wall 31, and both side walls 33 that partition the first oil recovery chamber 35, so that each of the walls 31 to 33 The protruding wall 76 can appropriately block the flow of the remaining oil flowing downstream along the wall surface. As a result, oil recovery efficiency can be further improved.

Further, in this embodiment, the first drain port 37a is provided on the side closer to the first oil separation section 60. Thereby, the oil separated by the first oil separation section 60 can be efficiently recovered. Furthermore, by separating the first drain port 37a from the second oil separation section 70, it is possible to suppress the remaining oil blown back from the first drain port 3a from directly entering the second ventilation port 74 of the second oil separation section 70. I can do it. As a result, oil recovery efficiency can be further improved.

Furthermore, in this embodiment, the bottom surface portion 35a of the first oil recovery chamber 35 has an inclined portion 35b that slopes from the position where the second oil separation portion 70 is provided toward the first drain port 37a. This makes it easier for the remaining oil that has fallen onto the bottom surface portion 35a to flow toward the first drain port 37a. As a result, oil recovery efficiency can be further improved.

Further, in this embodiment, the bottom surface portion 36a of the second oil recovery chamber 36 is located below the bottom surface portion 35a of the first oil recovery chamber 35. That is, there is a possibility that oil may also blow back from the second drain port 38a provided in the second oil recovery chamber 36. Therefore, by arranging the bottom part 36a of the second oil recovery chamber 36 as low as possible, even if oil is blown back from the second drain port 38a, the blown back oil will be able to reach the height where the blow-by gas is flowing. can be made difficult to reach. This makes it difficult for oil to flow into the outlet 39, thereby making it possible to further improve oil recovery efficiency.

FIG. 9 shows a first modification of this embodiment. In this first modification, the shape of the protruding wall is different. Physically, in the first modification, the protruding wall 176 has a rectangular cylindrical shape (here, a hexagonal cylindrical shape) when viewed from the upstream side. Further, as shown on the right side of FIG. 9, the protruding wall 176 does not have a tapered shape, but extends straight from the second main body portion 73 toward the upstream side.

Even with such a configuration, it is possible to suppress residual oil that has passed along the second partition wall 71 from flowing into the second ventilation port 74. In particular, by forming the rectangular tube so that the corner portion is located at the uppermost side, the remaining oil that has passed along the second partition wall 71 can easily flow downward. Thereby, oil recovery efficiency can be improved.

FIG. 10 shows a second modification of this embodiment. In this second modification, the shape of the protruding wall 76 is different. Specifically, in the second modification, the protruding wall 276 has a U-shape that opens downward when viewed from the upstream side. Further, as shown on the right side of FIG. 9, the protruding wall 276 does not have a tapered shape, but extends straight from the second main body portion 73 toward the upstream side.

Even if the protruding wall 276 is not cylindrical in this way, it is possible to suppress the residual oil that has passed along the second partition wall 71 from flowing into the second ventilation port 74. In particular, by extending the tip of the U-shape to the lower end of the second main body part 73, the remaining oil can easily reach the bottom part 35a. Thereby, oil recovery efficiency can be improved.

(Other embodiments)
The technology disclosed herein is not limited to the embodiments described above, and may be substituted without departing from the spirit of the claims.

For example, in the embodiment described above, the protruding wall 76 has a perfect circular shape, but it may have an elliptical shape. At this time, if the protruding wall 76 is formed so that the long axis direction is the vertical direction, the remaining oil will easily flow downward.

Further, in the embodiment described above, the first oil separator 62 and the second oil separator 72 have basically the same configuration except that the second oil separator 72 is provided with the protruding walls 76, 176, and 276. Ta. The present invention is not limited to this, and in order to improve the oil separation efficiency in the first oil separator 62, the structure may be changed from the second oil separator 72 in addition to the presence or absence of the protruding walls 76, 176, 276.

Further, in the embodiment described above, the second ventilation port 74 was located at the center of the second partition wall 71 when viewed from the upstream side. Not limited to this. The second ventilation port 74 may be located at a position offset from the center of the second partition wall 71.

The above-described embodiments are merely illustrative and should not be construed as limiting the scope of the present disclosure. The scope of the present disclosure is defined by the claims, and all modifications and changes that come within the range of equivalents of the claims are intended to be within the scope of the present disclosure.

The technology disclosed herein is useful as an oil separation structure for separating oil from blow-by gas generated within an engine.

1 Engine 5 Cylinder head cover (housing)
30 Oil separator chamber 35 First oil recovery chamber 35a Bottom part 35b Inclined part 37 First drain oil passage 37a First drain port 60 First oil separation part 70 Second oil separation part 71 Second partition wall 72 Second oil separator 74 Second ventilation port 76 Projecting wall 176 Projecting wall 276 Projecting wall

Claims (6)

An oil separation structure for separating oil from blow-by gas generated in an engine,
a housing having an oil separator chamber for separating the oil;
a first oil separation section disposed in the oil separator chamber and relatively located on the upstream side in the flow direction of the blow-by gas;
a second oil separation section disposed in the oil separator chamber and located downstream of the first oil separation section in the flow direction;
a drain oil passage provided in an oil recovery chamber between the first oil separation section and the second oil separation section and having a drain port into which the separated oil flows;
The second oil separation section is
a ventilation hole through which blow-by gas passes after passing through the first oil separation section;
a projecting wall provided around the ventilation port so as to at least partially surround the ventilation port when viewed from the upstream side in the flow direction, and protruding from an end surface on the oil recovery chamber side toward the upstream side in the flow direction; ,
has
The oil separation structure is characterized in that the protruding wall is provided only in the second oil separation part of the first oil separation part and the second oil separation part. The oil separation structure according to claim 1,
The second oil separation section includes an oil separator having the ventilation hole and the protruding wall,
The oil separator is fitted into a partition wall that partitions a space on the downstream side of the second oil separation section in the flow direction and the oil recovery chamber,
The oil separation structure is characterized in that the ventilation port is located at the center of the partition wall when viewed from the upstream side in the flow direction. The oil separation structure according to claim 1 or 2,
The oil separation structure is characterized in that the protruding wall has a cylindrical shape surrounding the ventilation hole when viewed from the upstream side in the flow direction. In the oil separation structure according to claim 3,
The oil separation structure is characterized in that the protruding wall has a tapered shape whose diameter increases toward the upstream side in the flow direction. In the oil separation structure according to any one of claims 1 to 4,
The oil separation structure is characterized in that the drain port is provided upstream of the center of the oil recovery chamber in the flow direction. In the oil separation structure according to any one of claims 1 to 5,
The oil separation structure is characterized in that a bottom portion of the oil recovery chamber has an inclined portion that slopes from a position where the second oil separation portion is provided toward the drain port.

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