JP2002242648A - Gas liquid separating device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a higher gas-liquid separating capability while restraining an engine from increasing in its size. SOLUTION: In order to separate an oil content in a blowby gas refluxed to an intake system, this gas-liquid separating device for engine comprises a labyrinth chamber 6 constituted of: a baffle wall 9 vertically provided to an inner surface of an outer wall of the head cover 1; and a bottom plate 11 abutting on a lower end edge of the baffle wall. In this gas-liquid separating device for engine, a centrifugal separation chamber 7 is provided for separating the oil content in the blowby gas by generating a swirl flow in the blowby gas, and an outlet side of the labyrinth chamber and an inlet side of the centrifugal separation chamber communicate with each other. Accordingly, the labyrinth chamber and the centrifugal separation chamber can be used together, thereby enhancing a gas-liquid separating efficiency. Further, since the blowby gas in which the oil content is previously separated by the labyrinth chamber flows into the centrifugal separation chamber, sufficient gas-liquid separating function is realized without increasing a size of the centrifugal separation chamber, thereby restraining the engine from increasing in its size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid separation device for an engine having a labyrinth chamber formed in a head cover for separating oil in blow-by gas circulated to an intake system.

[0002]

2. Description of the Related Art Ventilation in a crankcase is performed in order to suppress oil deterioration in an oil pan of an engine and to suppress pressure fluctuation in a crankcase due to movement of a piston of the engine. Since the breather air (blow-by gas) from the inside of the crankcase contains unburned components, it is recirculated into the intake air and reburned.

[0003] On the other hand, mist of lubricating oil is mixed in the breather air from the inside of the crankcase. If the breather air containing the oil is re-burned, it has an adverse effect on exhaust gas purification. The engine is provided with a gas-liquid separation device for separating the gas.

As this gas-liquid separation device, there is a device in which a labyrinth chamber is formed inside a head cover by a rib-shaped baffle wall hanging down from an inner surface of an upper wall of a head cover and a plate abutting on a lower edge of the baffle wall. It is known (see Japanese Utility Model Publication No. 61-40888).

[0005]

According to the prior art disclosed in the above publication, a relatively large volume is required in order to obtain a desired gas-liquid separation capacity, and an increase in the size of the engine cannot be avoided. .

There is also known a centrifugal oil separator configured to apply a swirling flow to a blow-by gas to be recirculated to an intake system and to perform gas-liquid separation by centrifugal force (Japanese Utility Model Application Laid-Open No. HEI 3-3103).
However, when a large amount of oil enters, the gas-liquid separation ability is significantly reduced.

The present invention has been devised in order to solve such disadvantages of the prior art. The main object of the present invention is to obtain an even higher gas-liquid separation capability while suppressing an increase in the size of an engine. It is an object of the present invention to provide an improved gas-liquid separation device for an engine.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, in order to separate oil in blow-by gas which is recirculated to an intake system, an inner surface of an outer wall of a head cover (1) is provided. Projected baffle wall (9)
And a plate (11) contacting an inner edge of the baffle wall.
And a centrifugal separation chamber (7) for generating a swirling flow in the blow-by gas to separate the oil component in the blow-by gas. The outlet side and the inlet side of the centrifugal separation chamber are communicated with each other. With this configuration, the labyrinth chamber and the centrifugal separation chamber can be used in combination, so that the gas-liquid separation efficiency can be further improved. In addition, since the blow-by gas from which oil has been separated in the labyrinth chamber flows into the centrifugal separation chamber, a sufficient gas-liquid separation action can be exerted without increasing the size of the centrifugal separation chamber, thereby suppressing the engine from becoming larger. can do.

In particular, if the configuration of the second aspect, that is, the labyrinth chamber and at least a part of the centrifugal separation chamber are integrally formed, the labyrinth chamber and the centrifugal separation chamber are reduced in the number of parts and the number of manufacturing steps. The head cover can be installed side by side without inviting, and the size of the head cover can be suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show a head cover of a single bank (or an in-line three-cylinder engine) of a V-type six-cylinder engine to which the present invention is applied. This head cover 1
Is formed by die-casting an aluminum alloy, for example, and has a substantially trapezoidal cross section orthogonal to the cylinder row, and a box-like shape in which the joining surface 2 to the cylinder head is substantially rectangular.

The rigidity of the head cover 1 is enhanced by extending the ribs 3 vertically and horizontally on the inner surface thereof.
A fixing bolt insertion hole 4 for the cylinder head;
The spark plug insertion hole 5 is provided at an appropriate position.

A labyrinth chamber 6 and a centrifugal separation chamber 7 for separating oil from blow-by gas filling the inside of the head cover 1 are provided inside an upper wall which is a part of an outer wall of the head cover 1. An oil return passage 8 for returning the used oil to the cylinder head is formed.

The labyrinth chamber 6, the centrifugal separation chamber 7, and the oil return passage 8 are provided with rib-shaped baffle walls 9a to 9d vertically suspended from the inner surface of the upper wall of the head cover 1 so that their lower ends are placed on the same plane. A liquid gasket is applied to the lower end edges of the baffle walls 9a to 9d, joined together, and formed by a common bottom plate 11 made of a metal plate fixed to the head cover 1 with bolts 10. By immersing the chambers 6 and 7 in the head cover 1 in this manner, space saving is promoted, and the chambers 6 and 7 are connected to the head cover 1.
It is intended to reduce the number of parts and the number of manufacturing steps by integrally molding the same.

A zigzag passage 12 is formed inside the labyrinth chamber 6 by alternately interlacing baffle walls 9d extending in a direction perpendicular to the cylinder row direction.
Are formed.

Labyrinth chamber 6 and oil return passage 8
Are formed adjacent to each other along the direction of the cylinder row, and communicate with each other via a cutout 13 provided at a key point on the lower end side of the baffle wall 9b separating each other (see FIG. 4). .

The centrifugal separation chamber 7 is disposed at a position sandwiched between the end of the labyrinth chamber 6 and the end of the oil return passage 8, and the peripheral wall 14 forming the same has a cylindrical shape. The outer end, that is, the upper end, is the head cover 1.
The mounting seat 16 for joining the PCV valve connecting member 15 is formed around the opening surface (see FIG. 3).

The PCV valve connecting member 15 includes a boss 19 provided with a screw hole 18 for screwing the PCV valve 17, and an outer surface of the head cover 1, that is, a mounting seat 16 on the upper surface.
Flange portion 21 fastened with two bolts 20
And a tubular passage body 22 suspended so as to protrude inward into the centrifuge chamber 7 along the central axis of the centrifuge chamber 7, and further into the centrifuge chamber 7 from the lower end of the tubular passage body 22. It consists of a round bar portion 23 that hangs down so as to protrude, and is fixed to the mounting seat 16 via a seal member 24. Since the mounting work of the PCV valve connecting member 15 can be performed from outside the head cover 1, it is relatively easy, and it can be confirmed that the bottom plate 11 is mounted at the time of the mounting work. Further, since the boss portion 19 protrudes outward, that is, upwards, from the flange portion 21 serving as the lid member, the workability for attaching and detaching the PCV valve 17 is good.

The centrifugal separation chamber 7 is located at an intermediate position in the axial direction of the tubular passage body portion 22 and a connection position with the round bar portion 23.
A plurality of (for example, two) disk-shaped baffle flanges 25.
6 are arranged in line. These two baffle collars 25.2
6, a through hole 28 communicating with the outflow passage 27 formed inside the tubular passage body 22 is provided. These through holes 28 and outflow passages 27 in the tubular passage body 22
The centrifugal separation chamber 7 communicates with the inlet of the PCV valve 17 screwed into the screw hole 18 of the boss portion 19 via the.

As described above, the boss 19 for mounting the PCV valve 17, the flange 21 as a cover member for closing the outer end opening of the centrifugal separation chamber 7, that is, the tubular member suspended in the centrifugal separation chamber 7. The passage body 22, a round bar 23 further suspended from the lower end of the tubular passage body 22, and two baffle flanges 25 arranged in the tubular passage body 22.
Reference numeral 26 is formed integrally with the PCV valve connection member 15, thereby achieving a significant reduction in the number of components.

Further, the PCV valve 17 is directly attached to the centrifugal separation chamber 7, and the blow-by gas heated in the labyrinth chamber 6 flows around the PCV valve 17, so that the PCV valve 17 is easily heated. Eliminates the need for special freeze protection. These points contribute to the promotion of downsizing of the engine and simplification of the structure.

A U-shaped groove 29 is formed on the outer surface of the head cover 1, that is, on the mounting seat 16 formed on the upper surface, so as to extend tangentially to the cylindrical inner peripheral surface of the centrifugal separation chamber 7. ). The end of the U-shaped groove 29 is communicated with the terminal end of the labyrinth chamber 6, and the open surface thereof is closed by the flange 21 of the PCV valve connection member 15. In this manner, the outer end, that is, the upper end of the centrifugal separation chamber 7 is opened on the upper wall of the head cover 1, and the mounting seat 1 to which the flange portion 21 closing the opening is joined.
By forming an inlet passage for the blow-by gas from the labyrinth chamber 6 to the centrifugal separation chamber 7 by depressing the outer surface, that is, the upper surface of 6, the passage can be easily formed without increasing the number of processing steps and the number of parts. it can.

A boss 31 for forming a screw hole 30 for screwing the flange fastening bolt 20 is formed on the side of the center of the centrifugal separation chamber 7 at the end of the U-shaped groove 29.
Are formed so as to protrude into the end portion of the labyrinth chamber 6. As described above, since the flange portion 21 is tightened on the side of the U-shaped groove 29, the sealing performance around the entrance passage can be easily improved. In addition, the boss 31 exerts a baffle function of disturbing the blow-by gas flow in the end portion of the labyrinth chamber 6, and also contributes to an improvement in oil separation efficiency.
Moreover, since the boss 31 is provided on the center side of the centrifugal separation chamber 7 in the side space of the U-shaped groove 29,
This contributes to further downsizing of the head cover 1.

The blow-by gas filled in the head cover 1 is introduced into the labyrinth chamber 6 through a number of holes 32 (see FIG. 1) formed at one end of the bottom plate 11 in the cylinder row direction. The blow-by gas introduced into the labyrinth chamber 6 flows through the zigzag passage 12 in the labyrinth chamber 6. On this occasion,
By colliding or contacting each of the baffle walls 9a, 9b, 9d constituting the passage 12, oil having a large specific gravity adheres to each of the baffle walls 9a, 9b, 9d. The oil separated from the blow-by gas in this way flows into the oil return passage 8 through the cutout 13 provided in the baffle wall 9b separating the labyrinth chamber 6 and the oil return passage 8.

The oil that could not be separated in the labyrinth chamber 6 is removed from the U
It flows into the centrifuge chamber 7 via a tangential passage consisting of a groove 29. As a result, the blow-by gas flow becomes a swirling flow, and the oil separated by the centrifugal force adheres to the inner peripheral surface of the centrifugal separation chamber 7 and the outer peripheral surface of the tubular passage body 22. Then, by passing through the gap between the outside, that is, the upper baffle flange 25, the separation of the oil component is further promoted. in this way,
Since the labyrinth chamber 6 for separating the oil component is provided in advance on the upstream side of the centrifugal separation chamber 7, a sufficient gas-liquid separation ability can be obtained without increasing the size of the centrifuge chamber 7.

The blow-by gas from which the oil has been almost removed as described above flows into the PCV valve 17 through the through hole 28 between the two baffle flanges 25 and 26 and the outflow passage 27 in the tubular passage body 22. The air is sent out to an intake passage (not shown) via a hose H connected to the PCV valve 17. In order to minimize the length of the hose H connecting the PCV valve 17 and the intake system, it is preferable to provide the centrifugal separation chamber 7 at the end of the head cover 1 near the intake system.

On the other hand, the oil separated in the centrifugal separation chamber 7 passes through a drain passage 33 formed on the contact surface between the baffle wall 9e and the bottom plate 11 so as to communicate with the bottom of the centrifuge chamber 7. After flowing into the drain chamber 34 formed at the end of the oil return passage 8, the oil return passage 8
The liquid is dripped into the cylinder head from a drain hole 35 provided at a key point of the bottom plate 11 in correspondence with the above. If the engine is mounted on the vehicle body with the cylinder axis inclined so that the oil return passage 8 is lower than the labyrinth chamber 6, the drain hole 35 is located at the lowest position of the oil return passage 8. Is opened, so that the efficiency of returning oil to the cylinder head can be increased.

Here, the drain passage 33 communicating with the bottom of the centrifugal separation chamber 7 extends tangentially to the inner peripheral surface of the cylinder of the centrifuge separation chamber 7. If the internal pressure is higher than the internal pressure and the oil is returned from the oil return passage 8 side, the return flow from the drain passage 33 becomes a swirling flow, so that the oil component is separated by the cyclone action and the oil flows through the tubular passage body 22. The oil separated once flows back into the through-hole 28 in conjunction with the oil catching action of the baffle flange 26 provided below the hole 28 and the round bar portion 23 vertically provided below the baffle flange 26, and the intake recirculation passage. Is prevented from being mixed into the blow-by gas into the blow-by gas.

In the above description, only the labyrinth chamber 6 and the centrifugal separation chamber 7 are provided on the upper wall of the head cover 1, but the positions of the labyrinth chamber 6 and the centrifugal separation chamber 7 are not limited thereto. Instead, it may be provided on the side wall of the head cover 1 in some cases.

[0030]

As described in detail above, a centrifugal separation chamber for generating a swirling flow in the blow-by gas to separate the oil in the blow-by gas is provided, and the outlet side of the labyrinth chamber and the inlet side of the centrifugal separation chamber communicate with each other. According to the configuration of the first aspect, the labyrinth chamber and the centrifugal separation chamber can be used in combination, so that the gas-liquid separation efficiency can be further improved. In addition, since the blow-by gas from which oil has been separated in the labyrinth chamber flows into the centrifugal separation chamber, a sufficient gas-liquid separation action can be exhibited without increasing the size of the centrifuge chamber.
Accordingly, a great effect can be obtained in achieving both high engine performance and compactness of the engine and sufficient gas-liquid separation capability.

[0031] In particular, according to the configuration of the second aspect, the centrifugal separation chamber is at least partially integrated with the labyrinth chamber, and the labyrinth chamber and the centrifugal separation chamber are reduced in the number of parts and the number of manufacturing steps. Since it can be attached to the head cover without inviting, and the head cover can be suppressed from being enlarged, a great effect can be obtained in promoting the downsizing of the engine and the simplification of the structure.

[Brief description of the drawings]

FIG. 1 is a bottom view of an engine head cover to which the present invention is applied, as viewed from a joint surface with a cylinder block.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a top view of a main part of a single engine head cover to which the present invention is applied.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head cover 6 Labyrinth chamber 7 Centrifuge chamber 9 Baffle wall 11 Bottom plate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masayuki Takahashi 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3G015 BD10 BD23 BE05 BF05 CA05 DA01 DA04 DA11 EA07 EA09

Claims (2)

[Claims] 1. A labyrinth formed by a baffle wall protruding from an inner surface of an outer wall of a head cover and a plate abutting on an inner edge of the baffle wall to separate oil in a blow-by gas circulated to an intake system. A gas-liquid separation device for an engine having a chamber, comprising: a centrifugal separation chamber that generates a swirling flow in a blow-by gas to separate an oil component in the blow-by gas; an outlet side of the labyrinth chamber and an inlet side of the centrifuge chamber. And a gas-liquid separation device for an engine. 2. The gas-liquid separation device for an engine according to claim 1, wherein the centrifugal separation chamber is at least partially integrated with the labyrinth chamber.