JP5488041B2 - Oil separator - Google Patents

Description

  The present invention relates to an oil separator for separating oil mist from oil mist-containing gas such as blow-by gas in an engine.

  In general, an engine is provided with a PCV (positive crankcase ventilation) for collecting blow-by gas flowing out from a combustion chamber into the crankcase without releasing it into the atmosphere. The blow-by gas is returned from the crankcase to the intake system by this PCV, and the blow-by gas is combusted. In this case, the oil is present as fine particles (oil mist) in the blow-by gas, so that the oil mist is separated from the blow-by gas and returned to the crankcase without burning the blow-by gas as it is. A separator is used.

As this type of conventional oil separator, for example, configurations as disclosed in Patent Document 1 and Patent Document 2 have been proposed.
In the conventional configuration described in Patent Document 1, a gas passage through which oil mist-containing gas flows is formed inside the housing. A partition wall is provided in the gas passage in the housing, and an orifice for accelerating the gas flow is formed in a part of the partition wall. A collision plate with which a gas flow collides is disposed opposite to the downstream side of the orifice in the housing. A rectangular wave-shaped uneven surface is formed on the side surface of the collision plate facing the partition wall so that the contact area of the collision plate with the gas is expanded. The gas that has passed through the orifice collides with the collision plate, whereby oil mist contained in the gas is separated.

  In the conventional configuration described in Patent Document 2, two independent gas introduction paths through which oil mist-containing gas flows are formed inside the housing. On the downstream side of both the gas introduction paths, a gas junction path is provided so that the gases introduced from both gas introduction paths collide with each other and merge. A perforated plate is provided on the downstream side of the gas combining passage, and a plurality of through holes for increasing the gas flow are formed in the perforated plate. In the housing, on the downstream side of the through-hole, a flat collision plate on which a gas flow collides is disposed oppositely. The oil mist-containing gas introduced from the two gas introduction passages collides with each other in the gas joint passage, whereby the particle size of the oil mist contained in the gas is increased. Thereafter, when the gas passes through the through hole and collides with the collision plate, the oil mist contained in the gas is separated.

JP 2008-157047 A JP 2008-121478 A

However, these conventional configurations have the following problems.
In the conventional configuration described in Patent Document 1, the oil separated on the uneven surface is dropped from the uneven surface and recovered from the drain hole below, but the gas after oil mist separation is the uneven surface. It is designed to flow underneath. Therefore, once separated oil mist is mixed again in the gas, there is a possibility that the separation performance of the oil mist is lowered.

  In the conventional configuration described in Patent Document 2, the oil mist having a larger particle size due to gas collision at the merging portion is attached onto the flat collision plate. Therefore, when the gas flow velocity increases, the oil mist adheres to the collision plate. The oil mist that has been removed is mixed again in the gas, and the oil mist separation performance may be lowered as in Patent Document 1.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide an oil separator capable of suppressing re-scattering of separated oil mist and re-mixing into gas, and improving oil mist separation performance.

In order to achieve the above object, the present invention provides an oil separator in which a passage through which oil mist-containing gas flows is formed in the housing, and a separation means for separating oil mist from the gas is provided in the passage. The separation means includes an orifice for accelerating the gas flow, a guide surface for guiding the gas to converge toward the orifice, and a concave where the oil mist-containing gas ejected from the orifice collides. constituted by a collision surface, only set a gap that forms a part of the passage between the impact surface and the orifice, provided in a plurality of stages along said separating means in an extending direction of said passageway, said plurality of stages Each guide surface in the separating means is characterized in that the downstream one is elongated in the passage extension direction .

  Therefore, in the oil separator according to the present invention, the oil mist-containing gas flowing through the gas passage is guided to the orifice along the guide surface, and then ejected toward the concave collision surface while being accelerated through the orifice. . Then, when the ejected gas collides with the collision surface, oil mist contained in the gas adheres to the collision surface and is separated. In this case, the attached oil mist flows down in a state surrounded by the concave collision surface, and the gas colliding with the collision surface flows downstream through the gap between the collision surface and the orifice. It is possible to prevent the mist from being re-scattered by the gas flow and being mixed again in the gas. Therefore, the oil mist separation performance can be improved.

The said structure WHEREIN: It is good to narrow each orifice in the said multistage separation | separation means, the thing downstream.
In the above-described configuration, it is preferable that another guide surface for guiding the gas in the lateral direction is formed on both sides of the collision surface.
In the above-described configuration, it is desirable to form another gap continuous with the gap between the collision surface and the side wall of the housing.

In the above-described configuration, it is desirable to provide an oil discharge port in the housing bottom wall at the lower end of the collision surface .

  As described above, according to the present invention, the re-scattering of the separated oil mist can be suppressed, and the effect that the separation performance of the oil mist can be improved is exhibited.

The principal part longitudinal cross-sectional view which shows the oil separator of 1st Embodiment. Sectional drawing in the 2-2 line of FIG. Sectional drawing in the 3-3 line of FIG. The principal part cross-sectional view which shows the oil separator of 2nd Embodiment. The principal part perspective view of the oil separator of 3rd Embodiment. The fragmentary sectional view of the oil separator of a 4th embodiment. The fragmentary sectional view of the oil separator of a 5th embodiment. The fragmentary sectional view of the oil separator of a 6th embodiment. The fragmentary sectional view of the oil separator of a 7th embodiment.

(First embodiment)
Below, 1st Embodiment of the oil separator which actualized this invention is described according to FIGS. 1-3.

  As shown in FIGS. 1 and 2, the oil separator 11 of this embodiment is disposed on a cylinder head cover 12 made of synthetic resin in an engine. The housing 13 of the oil separator 11 has a substantially square box shape and is formed integrally with the cylinder head cover 12. A gas inlet 14 communicating with the crank chamber of the engine is formed in the bottom wall 13a on one side of the housing 13. A gas outlet 15 connected to an intake passage of an intake system of the engine is formed on the upper wall 13b on the other side of the housing 13. Between the gas inlet 14 and the gas outlet 15, there is a gas passage 16 in the housing 13 in which blow-by gas, which is an oil mist-containing gas, flows by a suction action based on the negative pressure of the intake system. Is formed.

  A separation mechanism 17 as a separation means for separating oil mist from the gas is disposed in the gas passage 16 in the housing 13. The separation mechanism 17 is arranged in a plurality of stages (three stages in the embodiment) along the extending direction of the gas passage 16. In this embodiment, the separation mechanisms 17 arranged in a plurality of stages are configured to have the same structure.

  In each separation mechanism 17, a partition wall 18 is formed integrally with the inner wall surface of the housing 13 in the gas passage 16 so as to block the gas passage 16. The partition wall 18 is provided with one cylindrical orifice 19 through which blow-by gas is passed and the flow velocity is increased. A funnel-shaped guide surface 20 for guiding gas toward the orifice 19 is formed on the upstream side of the orifice 19 in the partition wall 18. Then, the blow-by gas flowing through the gas passage 16 is converged toward the orifice 19 by the guide surface 20, and then accelerated at the orifice 19 and ejected downstream.

  As shown in FIGS. 1 and 3, a collision plate 21 is erected integrally between the bottom wall 13 a and the top wall 13 b of the housing 13 so as to be positioned on the downstream side of the partition wall 18. A gap 22 for securing the gas passage 16 is formed between both side edges of the collision plate 21 and the side wall 13 c of the housing 13. At the center of the side surface of the collision plate 21 facing the orifice 19, a concave groove-shaped collision surface 21 a is formed that is recessed in a substantially triangular cross section where blow-by gas ejected from the orifice 19 collides. As shown in FIGS. 1 and 3, the collision surface 21 a is formed between the upper wall 13 b and the bottom wall 13 a of the housing 13 so as to extend over the entire length in the vertical direction of the collision plate 21. The blow-by gas ejected from the orifice 19 collides with the concave groove-shaped collision surface 21a, whereby oil mist contained in the gas adheres to the collision surface 21a and is separated. On both sides of the collision surface 21a, sleeve plate surfaces 21b constituting a guide surface for guiding gas toward the gap 22 are formed.

  A gap 23 that forms a part of the gas passage 16 is formed between the collision surface 21 a and sleeve plate surface 21 b of the collision plate 21 and the orifice 19 of the partition wall 18. Then, the blow-by gas ejected from the orifice 19 and colliding with the collision surface 21a is promptly guided to both sides of the collision plate 21 through the gap 23 along the sleeve plate surface 21b without staying in the vicinity of the collision surface 21a. Accordingly, it flows through the gap 22 between the side edges of the collision plate 21 and the side wall 13c of the housing 13 to the downstream side.

  Corresponding to the lower end of the collision surface 21 a of the collision plate 21, a flat triangular oil discharge port 24 is formed in the bottom wall 13 a of the housing 13. A cover 25 for preventing oil in the cylinder head cover 12 from entering the housing 13 is integrally formed at the lower portion of the oil discharge port 24. The oil separated and flowing down at the collision surface 21a of the collision plate 21 is collected from the oil discharge port 24 into the cylinder head cover 12 and returned to the oil pan (not shown), and a movable part such as a cam shaft (not shown). Used for lubrication.

Next, the operation of the oil separator 11 configured as described above will be described.
When the engine is operated, blow-by gas is introduced into the housing 13 from the gas inlet 14 shown in FIG. It flows to the outlet 15 side. At this time, blow-by gas that has flowed into the gas passage 16 from the gas inlet 14 is focused toward the orifice 19 by the guide surface 20 in the first-stage separation mechanism 17, and then increases downstream from the orifice 19. It spouts quickly. The ejected gas collides with the collision surface 21a of the collision plate 21, whereby oil mist contained in the gas adheres to the collision surface 21a and is separated. At this time, in the first stage, out of the oil mist, the oil mist having a large particle size is separated by adhering to the collision surface 21a. That is, the oil mist having a large particle diameter is less likely to drift and easily adheres to the collision surface 21a, and therefore is preferentially separated in the first stage.

  Since the collision surface 21a is formed in a concave groove shape and extends over the entire length in the vertical direction of the housing 13, the oil mist separated by adhesion flows down in a state surrounded by the concave groove-shaped collision surface 21a. . At the same time, a gap 23 that forms the gas passage 16 is provided between the collision surface 21a and the sleeve plate surface 21b and the orifice 19, so that the gas that has collided with the collision surface 21a has sleeve plate surfaces on both sides of the collision surface 21a. It flows downstream through the gap 23 along 21b. Therefore, there is almost no possibility that the oil mist on the collision surface 21a is re-scattered by the gas flow or returned into the gas, and quickly flows down to the lower end side of the collision surface 21a as an oil droplet.

  The oil that has flowed down from the collision surface 21a is discharged out of the housing 13 through an oil discharge port 24 formed in the bottom wall 13a of the housing 13 immediately below the collision surface 21a, and is collected inside the cylinder head cover 12. . On the other hand, the blow-by gas from which the oil mist has been separated in the first stage separation mechanism 17 is sequentially introduced into the subsequent second stage and third stage separation mechanisms 17. In the second and third stage separation mechanisms 17 as well, the oil mist remaining in the blow-by gas is separated and captured by the collision surface 21a by the same operation as the first stage separation mechanism 17. . In this case, the oil mist having a larger particle size is separated by the upper separation mechanism 17, and the oil mist having a smaller diameter is separated by the third separation mechanism 17 as the final stage. Accordingly, the blow-by gas that has passed through the third-stage separation mechanism 17 contains almost no oil mist. The blow-by gas that has passed through the third-stage separation mechanism 17 is returned from the gas outlet 15 to the engine intake system.

  In addition, oil mist in gas adheres to the upstream surface of each partition wall 18 and the sleeve plate surface 21b to perform oil separation. The oil attached in this way is recovered from the oil discharge port 24 or another oil discharge port (not shown) provided in the bottom wall 13a of the housing 13.

Therefore, according to this embodiment, the following effects can be obtained.
(1) In this oil separator, blow-by gas containing oil mist is accelerated by the orifice 19 through the guide surface 20, and thus collides with the collision surface 21a at high speed. For this reason, high separation efficiency can be obtained. And since the separation is performed in three stages, the oil mist contained in the blow-by gas can be effectively separated from those having a large particle size to those having a small particle size.

(2) Moreover, since the collision surface 21a that separates the oil is formed in a concave shape, it is possible to prevent the separated oil from being mixed again into the gas due to re-scattering.
(3) Although the separated oil flows down along the collision surface 21a, the blow-by gas from which the oil has been separated flows laterally from the gap 23 toward the gap 22, so that the separated oil is gas in the same manner as described above. It is possible to suppress re-mixing in.

  (4) Since the oil discharge port 24 is provided in the bottom wall 13a of the housing 13 at the lower end of the collision surface 21a, the oil that flows down along the collision surface 21a is quickly transferred from the oil discharge port 24 toward the oil pan. It can be moved to and collected. For this reason, it is possible to avoid the risk that the oil retained in the housing 13 is contained again in the gas.

  (5) The blow-by gas collided with the collision surface 21a flows laterally in the gap 23 along the sleeve plate surface 21b from the position of the collision surface 21a, then changes direction to the gap 22 and reverses from there. The flow then flows along the upstream surface of the partition wall 18, and further changes the direction along the guide surface 20 of the partition wall 18. This repetition is performed a plurality of times. For this reason, the gas is in a state similar to flowing while meandering in the passage of the labyrinth structure. Accordingly, oil mist is captured by the sleeve plate surface 21b and the inner side surface of the side wall 13c of the housing 13 during the meandering, so that the oil separation efficiency can be further improved.

(Second Embodiment)
Next, a second embodiment of an oil separator embodying the present invention will be described. In addition, about each embodiment after this 2nd Embodiment, and a modified example, it demonstrates centering on a different part from 1st Embodiment.

  In the second embodiment, as shown in FIG. 4, the orifices 19 in the multi-stage separation mechanism 17 are configured to be narrowed and narrowed toward the downstream side. That is, the inner diameter R of the orifice 19 in the first to third stage separation mechanisms 17 is configured so that the downstream one gradually decreases. Further, each guide surface 20 in the multi-stage separation mechanism 17 is configured such that the downstream one is longer in the passage extension direction. That is, the length L of the guide surface 20 in the first to third stage separation mechanisms 17 is configured to become gradually longer toward the downstream side. With this configuration, the rate of increase of the gas flow ejected from the orifice 19 increases toward the downstream side, and the oil mist having a small particle diameter that tends to drift in the downstream separation mechanism 17 can be efficiently captured. For this reason, in this 2nd Embodiment, it can isolate | separate effectively from the oil mist with a large particle size to the oil mist with a small particle size.

Therefore, according to the second embodiment, in addition to the effects described in (1) to (5) in the first embodiment, the following effects can be obtained.
(6) In the multi-stage separation mechanism 17, since the speed is increased toward the downstream side, the separation efficiency of the oil mist having a small particle diameter is excellent toward the downstream side. On the other hand, most of the oil mist having a large particle diameter is captured by the upper separation mechanism 17. Therefore, oil mists having different particle sizes contained in the gas can be efficiently separated from those having a large particle size with a small efficiency, and the oil mist separation performance can be further improved.

(Third embodiment)
Next, a third embodiment of the oil separator embodying the present invention will be described.
In the third embodiment, as shown in FIG. 5, the orifice 19 is formed in a vertical groove shape corresponding to the concave groove-shaped collision surface 21 a, and the guide surface 20 is the same length as the vertical length of the orifice 19. It is comprised by the inclined surface.

  Therefore, also in the third embodiment, substantially the same effects as the effects described in (1) to (5) in the first embodiment can be obtained. In particular, the third embodiment has the following effects.

(7) Since the orifice 19 and the guide surface 20 are extended in the vertical direction and provided over a wide range, it is effective when the flow rate of blow-by gas is large.
(Fourth embodiment)
Next, a fourth embodiment of an oil separator embodying the present invention will be described.

  In the fourth embodiment, as shown in FIG. 6, the sleeve plate surface 21 b is not formed, but a concave groove-shaped collision surface 21 a that is recessed in a substantially triangular shape is formed on the entire side surface of the collision plate 21. ing.

Therefore, also in the fourth embodiment, substantially the same effects as the effects described in (1) to (5) in the first embodiment can be obtained.
(Fifth embodiment)
Next, a fifth embodiment of the oil separator embodying the present invention will be described.

  In the fifth embodiment, as shown in FIG. 7, the guide surface 20 is formed so as to be continuously connected in a circular arc shape from the side surface of the partition wall 18 to the inner surface of the orifice 19. With this configuration, the gas is smoothly focused along the guide surface 20.

  Therefore, also in the fifth embodiment, substantially the same effects as the effects described in (1) to (5) in the first embodiment can be obtained. In particular, the fifth embodiment has the following effects.

  (8) Since the guide surface 20 is smoothly continuous in an arc shape toward the orifice 19, the blow-by gas can be prevented from becoming a turbulent flow, and therefore the oil mist separation efficiency can be further improved.

(Sixth embodiment)
Next, a sixth embodiment of an oil separator embodying the present invention will be described.
In the sixth embodiment, as shown in FIG. 8, among the plurality of stages of separation mechanisms 17, the collision surface 21 a of the third stage separation mechanism 17 disposed on the most downstream side has a porous material such as a nonwoven fabric. A porous portion 28 made of a porous material is provided.

Therefore, according to the sixth embodiment, in addition to the effects described in (1) to (5) in the first embodiment, the following effects can be obtained.
(9) The porous portion 28 provided on the collision surface 21a of the third-stage separation mechanism 17 can efficiently capture oil mist having a fine particle size, and further improve the oil mist separation performance. Can be improved.

(Seventh embodiment)
Next, a seventh embodiment of an oil separator embodying the present invention will be described.
In the seventh embodiment, as shown in FIG. 9, the sleeve plate surface 21b is formed in a gentle arc shape toward both side edges and the collision surface 21a.

Therefore, according to the seventh embodiment, in addition to the effects described in (1) to (5) in the first embodiment, the following effects can be obtained.
(10) Since the sleeve plate surface 21b continues in an arc shape toward both side edges and the collision surface 21a, the turbulent flow of blow-by gas at this portion can be suppressed, and therefore into the gas of the separated oil mist. Re-scattering can be prevented, and the separation efficiency can be further increased.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In each of the above embodiments, the number of stages of the separation mechanism 17 as the separation unit is set to one, two, or four or more.

In other embodiments than the third embodiment shown in FIG. 5, a plurality of orifices 19 and guide surfaces 20 are provided in the vertical direction along the concave groove-shaped collision surface 21a.
In the second embodiment, the diameter of the orifice 19 is reduced toward the downstream side and the guide surface 20 is lengthened, but one of these configurations should be adopted.

  -Combining the configuration of each of the embodiments. For example, by combining the configurations of the second and third embodiments, the diameter of the orifice 19 extended in the vertical direction and the length of the guide surface 20 are changed as in the second embodiment.

  An orifice 19 and guide surfaces 20 for guiding the gas flow to the orifice 19 are provided at a plurality of positions in the left-right direction of the partition wall 18.

  DESCRIPTION OF SYMBOLS 11 ... Oil separator, 13 ... Housing, 13a ... Bottom wall, 13c ... Side wall, 14 ... Gas inlet, 15 ... Gas outlet, 16 ... Gas passage, 17 ... Separation mechanism as a separation means, 18 ... Septum, 19 ... Orifice, 20 ... guide surface, 21 ... impact plate, 21a ... impact surface, 23 ... gap, 24 ... oil discharge port.

Claims (5)

An oil separator in which a passage through which oil mist-containing gas flows is formed in the housing, and a separation means for separating oil mist from the gas is provided in the passage,
The separation means includes an orifice for accelerating the gas flow, a guide surface that guides the gas to converge toward the orifice, and a concave collision surface on which the oil mist-containing gas ejected from the orifice collides. configured, setting the gap to form the part of the passage between the impact surface and the orifice,
The separating means is provided in a plurality of stages along the extending direction of the passage,
An oil separator characterized in that the guide surfaces in the plurality of stages of separation means are elongated in the direction of passage extension toward the downstream side . 2. The oil separator according to claim 1 , wherein each of the orifices in the plurality of stages of separation means is narrower toward the downstream side. The oil separator according to claim 1 or 2 , wherein another guide surface for guiding the gas in a lateral direction is formed on both sides of the collision surface. The oil separator according to any one of claims 1 to 3 , wherein another gap continuous with the gap is formed between the collision surface and the side wall of the housing. The oil separator according to any one of claims 1 to 4 , wherein an oil discharge port is provided in a housing bottom wall at a lower end of the collision surface.

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