U.S. patent application number 16/214263 was filed with the patent office on 2019-06-13 for oil separators.
This patent application is currently assigned to KOJIMA INDUSTRIES CORPORATION. The applicant listed for this patent is KOJIMA INDUSTRIES CORPORATION, TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Masami ISHIKAWA, Hirotaka MATSUDA, Tomoki NAKAMURA, Takuya SUZUKI, Naoya TAMURA.
Application Number | 20190178122 16/214263 |
Document ID | / |
Family ID | 66735188 |
Filed Date | 2019-06-13 |
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United States Patent
Application |
20190178122 |
Kind Code |
A1 |
SUZUKI; Takuya ; et
al. |
June 13, 2019 |
Oil Separators
Abstract
An oil separator for trapping oil mist contained in blow-by gas
includes a separation plate, an upstream oil-mist trapping chamber,
and a downstream oil-mist trapping chamber. The upstream and
downstream oil-mist trapping chambers are divided by the separation
plate. The upstream oil-mist trapping chamber communicates with a
flow inlet for blow-by gas. The downstream oil-mist trapping
chamber communicates with the upstream oil-mist trapping chamber
and communicates with a flow outlet for blow-by gas. A return port
formed through the separation plate returns oil mist trapped in the
downstream oil-mist trapping chamber into the upstream oil-mist
trapping chamber. The return port is positioned vertically above
the bottom surface of the upstream oil-mist trapping chamber and is
positioned at substantially the same vertical level as the
lowermost portion of the bottom surface of the downstream oil-mist
trapping chamber.
Inventors: |
SUZUKI; Takuya; (Toyota-shi,
JP) ; MATSUDA; Hirotaka; (Toyota-shi, JP) ;
TAMURA; Naoya; (Toyota-shi, JP) ; ISHIKAWA;
Masami; (Aichi-gun, JP) ; NAKAMURA; Tomoki;
(Okazaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOJIMA INDUSTRIES CORPORATION
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi
Toyota-shi |
|
JP
JP |
|
|
Assignee: |
KOJIMA INDUSTRIES
CORPORATION
Toyota-shi
JP
TOYOTA JIDOSHA KABUSHIKI KAISHA
Toyota-shi
JP
|
Family ID: |
66735188 |
Appl. No.: |
16/214263 |
Filed: |
December 10, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01M 13/04 20130101;
F01M 13/0405 20130101; F01M 2013/0461 20130101 |
International
Class: |
F01M 13/04 20060101
F01M013/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 11, 2017 |
JP |
2017-236918 |
Claims
1. An oil separator for trapping oil mist contained in blow-by gas,
the oil separator comprising: an upstream oil-mist trapping chamber
in fluid communication with a flow inlet for blow-by gas; a
downstream oil-mist trapping chamber positioned adjacent to the
upstream oil-mist trapping chamber and separated from the upstream
oil-mist trapping chamber by a separation plate; a communication
port in fluid communication with the upstream oil-mist trapping
chamber and the downstream oil-mist trapping chamber; a flow outlet
configured to allow blow-by gas from the downstream oil-mist
trapping chamber to flow outside of the oil separator; and a return
port extending through the separation plate and configured to allow
oil mist trapped in the downstream oil-mist trapping chamber to
return into the upstream oil-mist trapping chamber; wherein the
return port is positioned above a bottom surface of the upstream
oil-mist trapping chamber and is positioned at substantially the
same height as a lowermost portion of a bottom surface of the
downstream oil-mist trapping chamber.
2. The oil separator of claim 1, wherein the separation plate
comprises: a wall surface facing opposite to the upstream oil-mist
trapping chamber; and a rib formed on the wall surface proximal the
return port, wherein the rib is configured to prevent blow-by gas
from flowing from the upstream oil-mist trapping chamber into the
downstream oil-mist trapping chamber through the return port.
3. The oil separator of claim 2, wherein the rib has a U-shape
configuration and extends along the return port.
4. The oil separator of claim 2, wherein the rib has a U-shape
configuration and extends in an arc shape around the return
port.
5. The oil separator of claim 4, wherein the arc extends more than
180 degrees about the return port.
6. An oil separator for trapping oil mist contained in blow-by gas,
the oil separator comprising: a liquid oil trapping chamber
including at least one hole configured to allow liquid oil to exit
under the force of gravity; an upstream oil-mist trapping chamber
in fluid communication with the liquid oil trapping chamber; a
downstream oil-mist trapping chamber positioned adjacent to the
upstream oil-mist trapping chamber and separated from the upstream
oil-mist trapping chamber by a separation plate; a communication
port configured to allow the upstream oil-mist trapping chamber to
communicate with the downstream oil-mist trapping chamber; a flow
outlet configured to allow blow-by gas from the downstream oil-mist
trapping chamber to flow outside of the oil separator; and a return
port formed through the separation plate and configured to allow
oil mist trapped in the downstream oil-mist trapping chamber to
return into the upstream oil-mist trapping chamber; wherein the
return port is positioned vertically above a bottom surface of the
upstream oil-mist trapping chamber and is positioned at
substantially the same vertical level as a lowermost portion of a
bottom surface of the downstream oil-mist trapping chamber.
7. An oil separator for trapping oil mist contained in blow-by gas,
the oil separator comprising: a liquid oil trapping chamber; an
upstream oil-mist trapping chamber downstream of the liquid oil
trapping chamber, wherein the liquid oil trapping chamber is in
fluid communication with a flow inlet for blow-by gas from the
upstream liquid oil trapping chamber; a downstream oil-mist
trapping chamber positioned adjacent to the upstream oil-mist
trapping chamber and separated from the upstream oil-mist trapping
chamber by a separation plate; a communication port configured to
allow the upstream oil-mist trapping chamber to communicate with
the downstream oil-mist trapping chamber; a flow outlet configured
to allow blow-by gas from the downstream oil-mist trapping chamber
to flow outside of the oil separator; and a return port formed
through the separation plate such that the return port allows oil
mist trapped in the downstream oil-mist trapping chamber to return
into the upstream oil-mist trapping chamber; wherein the return
port is located at a level higher than a bottom surface of the
upstream oil-mist trapping chamber and is positioned at
substantially the same level as a lowermost portion of a bottom
surface of the downstream oil-mist trapping chamber.
8. The oil separator of claim 7, wherein the liquid oil trapping
chamber includes two holes formed in a bottom portion thereof,
wherein the two holes are configured to allow liquid oil to exit
the liquid oil trapping chamber under the force of gravity.
9. The oil separator claim 8, wherein the two holes formed in the
bottom portion of the liquid oil trapping chamber are laterally
spaced apart.
10. The oil separator of claim 9, wherein a first collision wall
extends obliquely and upward from proximal a center of the two
holes and forms a barrier for large particle size liquid oil
contained in blow-by gas, wherein the first collision wall is made
of resin material such that the oil adheres thereto.
11. The oil separator of claim 7, wherein the separation plate
includes a wall surface facing opposite to the upstream oil-mist
trapping chamber and a rib formed on the wall surface proximal the
return port such that the rib prevents blow-by gas from flowing
from the upstream oil-mist trapping chamber into the downstream
oil-mist trapping chamber through the return port.
12. The oil separator of claim 7, wherein the rib has a U-shape
configuration and extends about at least a portion of the return
port.
13. The oil separator of claim 11, wherein the rib has a U-shape
configuration and extends circumferentially in an arc shape around
the return port.
14. The oil separator of claim 13, wherein the arc extends
angularly more than 180 degrees about the return port.
15. The oil separator of claim 11, wherein the rib is formed in a
V-shape configuration.
16. The oil separator of claim 11, wherein the rib is formed in a
horseshoe configuration.
17. The oil separator of claim 7, wherein the liquid oil trapping
chamber is positioned adjacent to and immediately below the
downstream oil-mist trapping chamber.
18. The oil separator of claim 7, wherein the communication port
has a square-shaped void configuration.
19. The oil separator of claim 7, wherein the liquid oil trapping
chamber is positioned immediately adjacent to the upstream oil-mist
trapping chamber.
20. The oil separator of claim 7, wherein the downstream oil-mist
trapping chamber is located laterally adjacent to the upstream oil
mist trapping chamber, and wherein the downstream oil-mist trapping
chamber is located directly above and adjacent to the liquid oil
trapping chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Japanese patent
application serial number 2017-236918 filed Dec. 11, 2017, which is
hereby incorporated herein by reference in its entirety for all
purposes.
BACKGROUND
[0002] The present disclosure relates to an oil separator, and more
specifically, it relates to an oil separator to trap oil mist
contained in blow-by gas.
[0003] A conventional positive crankcase ventilation (PCV) system,
which is employed in an internal combustion engine like an
automobile engine, is known in the art. Air pollution may result
when blow-by gas (un-combusted gas) leaks and/or is discharged from
a gap between a piston ring and a cylinder wall of the engine to
the exterior atmosphere during operation of the engine. To prevent
such leakage of the blow-by gas, the PCV system collects the
blow-by gas and then returns the collected blow-by gas to an air
intake system. The returned blow-by gas then undergoes
re-combustion within the engine. The blow-by gas contains oil mist,
which is lubricant oil such as engine oil dispersed as micro
particles. The PCV system includes an oil separator designed to
trap the oil mist contained in the blow-by gas and prevent the oil
mist from flowing into the air intake system. The oil separator is
provided in the middle of a flow passage that connects a crankcase
and an air-intake duct.
[0004] A conventional labyrinth-type oil separator 101, as
illustrated in FIG. 6, is disclosed, for example, in Japanese
Laid-Open Patent Publication No. 2009-68471. As illustrated in FIG.
7, the oil separator 101 includes a lower base 110, a middle base
130, and an upper base 140, where these bases 110, 130, 140 are
attached to each other by vibration welding. The oil separator 101
includes a liquid oil trapping chamber 150, a primary oil-mist
trapping chamber 151, and a secondary oil-mist trapping chamber
152, where each of the chambers 150, 151, 152 is defined between
two of the bases 110, 130, 140. The liquid oil trapping chamber 150
contains a compartmented interior space therein, which is capable
of trapping liquid oil with a relatively large particle size (not
shown). The primary oil-mist trapping chamber 151 is located
downstream of the liquid oil trapping chamber 150 and contains a
compartmented interior space therein, which is capable of trapping
oil mist with a relatively small particle size (not shown).
[0005] As illustrated in FIG. 7, the secondary oil-mist trapping
chamber 152 is arranged adjacent to the primary oil-mist trapping
chamber 151 via a separation plate 131 of the middle base 130. The
secondary oil-mist trapping chamber 152 is located downstream of
the primary oil-mist trapping chamber 151 and contains
compartmentalized interior space, which is capable of trapping
oil-mist with a relatively small particle size. The separation
plate 131 has a first communication port 132, a second
communication port 133, and a return port 134. The first
communication port 132 allows the liquid oil trapping chamber 150
and the primary oil-mist trapping chamber 151 to communicate with
each other. The second communication port 133 allows the primary
oil-mist trapping chamber 151 and the secondary oil-mist trapping
chamber 152 to communicate with each other. The return port 134
allows communication between the primary oil-mist trapping chamber
151 and the secondary oil-mist trapping chamber 152, so as to allow
the oil mist trapped by the secondary oil-mist trapping chamber 152
to return to the primary oil-mist trapping chamber 151.
[0006] Containing more than one oil-mist trapping chambers (the
primary oil-mist trapping chamber 151 and the secondary oil-mist
trapping chamber 152 in this example), the oil separator provides a
passage having a long length for the blow-by gas, which has flown
into the oil separator 101. Such a configuration of the oil
separator 101, with a long length of passage, can enhance trapping
efficiency of the oil mist with a small diameter. The return port
134 allows the oil-mist trapped in the secondary oil-mist trapping
chamber 152 to merge with the oil mist trapped in the primary
oil-mist trapping chamber 151. The merged, trapped oil may be
collected together with the liquid oil trapped in the liquid oil
trapping chamber 150. This configuration allows the oil-mist
trapped in the secondary oil-mist trapping chamber 152 to be
collected without a dedicated collecting passage. As a result, the
size of the oil separator 101 may be reduced while the oil
separator 101 may efficiently trap and collect the oil mist with a
small particle size.
[0007] As illustrated in FIG. 8, the return port 134 is located
along the bottom surface 151a of the primary oil-mist trapping
chamber 151. Additionally, the return port 134 is located along the
lowermost portion 152b of the bottom surface 152a of the secondary
oil-mist trapping chamber 152. As a result, the return port 134 may
facilitate return of the oil-mist trapped in the secondary oil-mist
trapping chamber 152 to the primary oil-mist trapping chamber
151.
[0008] The blow-by gas, however, may contain a massive amount of
the liquid oil with a large particle size. In this case, the liquid
oil with a large particle size may flow from the liquid oil
trapping passage 150 into the primary oil-mist trapping chamber 151
through the first communication port 132. The liquid oil with a
large particle size may subsequently flow through the return port
134 (i.e., shortcut) from the primary oil-mist trapping chamber 151
into the secondary oil-mist trapping chamber 152 without passing
through the second communication port 133, and may finally flow out
of the oil separator 101 through an outlet port 113 at the lower
base 110. As a result, the liquid oil with a large particle size
may undesirably flow into an internal combustion engine located
downstream of the oil separator 101 and may be combusted, which may
cause a failure of the internal combustion engine.
SUMMARY
[0009] According to one aspect of the present disclosure, an oil
separator for trapping oil mist contained in blow-by gas includes a
separation plate, an upstream oil-mist trapping chamber, and a
downstream oil-mist trapping chamber. The upstream and downstream
oil-mist trapping chambers are divided by the separation plate and
are positioned adjacent to each other. The upstream oil-mist
trapping chamber communicates with a flow inlet for blow-by gas.
The downstream oil-mist trapping chamber communicates with the
upstream oil-mist trapping chamber and a flow outlet for blow-by
gas. A return port is configured to return oil mist trapped in the
downstream oil-mist trapping chamber back into the upstream
oil-mist trapping chamber. The return port is formed through the
separation plate. The return port is positioned above the bottom
surface of the upstream oil-mist trapping chamber and is positioned
at substantially the same vertical level as the lowermost portion
of the bottom surface of the downstream oil-mist trapping
chamber.
[0010] The oil contained in blow-by gas is separated from the
blow-by gas and drops in both of the upstream and downstream
oil-mist trapping chambers. The oil dropped in the downstream
oil-mist trapping chamber is allowed to pass through the return
port to the upstream oil-mist trapping chamber. On the other hand,
the oil dropped in the upstream oil-mist trapping chamber is
prevented from passing through the return port and flowing into the
downstream oil-mist trapping chamber. Consequently, the liquid oil
gathers in the upstream oil-mist trapping chamber and does not
accumulate in the downstream oil-mist trapping chamber.
Consequently, the liquid oil is prevented from flowing out of the
downstream oil-mist trapping chamber through the flow outlet and
subsequently being discharged to the outside. As a result, the
liquid oil is prevented from flowing to a device(s) such as an
internal combustion engine positioned downstream of the oil
separator and from being combusted in the internal combustion
engine. In this way, this configuration may prevent a device(s)
located downstream of the oil separator from being broken down.
[0011] According to another aspect of the present disclosure, the
separation plate includes a wall surface facing opposite to the
upstream oil-mist trapping chamber. The wall surface may be formed
with a rib in the vicinity of the return port. The rib is
configured to prevent blow-by gas from flowing into the return port
through the return port. Consequently, blow-by gas is prevented
from flowing from the upstream oil-mist trapping chamber through
the return port into the downstream oil-mist trapping chamber.
Thus, the blow-by gas tends not to flow through the return port but
through a communication port that communicates the upstream
oil-mist trapping chamber with the downstream oil-mist trapping
chamber, from the upstream oil-mist trapping chamber to the
downstream oil-mist trapping chamber.
[0012] According to another aspect of the present disclosure, the
rib may have a substantially U-shaped form. For example, the rib
may extend along the return port. Therefore, the blow-by gas may be
prevented from flowing from the upstream oil-mist trapping chamber
through the return port into the downstream oil-mist trapping
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of an oil separator according
to one exemplary embodiment.
[0014] FIG. 2 is an exploded view of the oil separator of FIG.
1.
[0015] FIG. 3 is a front view of a middle base of the oil separator
of FIG. 2.
[0016] FIG. 4 is a cross-sectional view of the oil separator of
FIG. 1 taken along a line IV-IV of FIG. 3.
[0017] FIG. 5 is a schematic view of an interior of the oil
separator of FIG. 1.
[0018] FIG. 6 is a perspective view of a conventional oil
separator.
[0019] FIG. 7 is an exploded view of the conventional oil separator
of FIG. 6.
[0020] FIG. 8 is a schematic view of an interior of the
conventional oil separator of FIG. 6.
DETAILED DESCRIPTION
[0021] As previously described, in some conventional oil
separators, the liquid oil with a large particle size may
undesirably flow into an internal combustion engine located
downstream of the oil separator and may be combusted. Thus, there
has been a need of an oil separator capable of: preventing liquid
oil contained in blow-by gas from flowing into a device located
downstream of the oil separator, and thereby suppressing a failure
of the device even when the blow-by gas contains a massive amount
of the liquid oil with a large particle size.
[0022] Hereinafter, an exemplary embodiment will be described with
reference to FIGS. 1 to 5. As illustrated in FIGS. 1 and 2, an oil
separator 1 is a labyrinth-type separator, and comprises a lower
base 10, a middle base 30, and an upper base 40.
[0023] As illustrated in FIG. 2, the lower base 10 is a casing
member having a recess 10a at a bottom and an opening 10b facing
the middle base 30. A first flow inlet 11 and a second flow inlet
12 are formed on a lower portion of the recess 10a to allow blow-by
gas (not illustrated) to flow into the oil separator 1. A flow
outlet 13 is formed on an upper portion of the lower base 10 to
allow the blow-by gas to flow out of the oil separator 1. A first
collision wall 14, a second collision wall 15, a third collision
wall 16, a fourth collision wall 17, a fifth collision wall 18, and
a sixth collision wall 19 are formed within the recess 10a.
[0024] As illustrated in FIGS. 3 and 4, the middle base 30 is a
panel member sized and shaped to cover the opening 10b of the lower
base 10. A lower region of the middle base 30 defines a liquid oil
trapping chamber 50 in cooperation with the lower base 10. The
upper region of the middle base 30 defines a secondary oil-mist
trapping chamber 52 in cooperation with the lower base 10. The
middle base 30 defines the secondary oil-mist trapping chamber 52
and has a separation plate 31, which separates the secondary
oil-mist trapping chamber 52 from a primary oil-mist trapping
chamber 51. The primary oil-mist trapping chamber 51 and the
secondary oil-mist trapping chamber 52 are arranged adjacent to
each other, to the left and right of the separation plate 31,
respectively. A first communication port 32, which allows the
liquid oil trapping chamber 50 to communicate with the primary
oil-mist trapping chamber 51, is formed on the right-most region of
the separation plate 31. A second communication port 33, which
allows the primary oil-mist trapping chamber 51 to communicate with
the secondary oil-mist trapping chamber 52, is formed on the
uppermost region of the separation plate 31. A return port 34 is
formed at the separation plate 31. The return port 34 allows small
particle size oil mist (not illustrated) trapped in the secondary
oil-mist trapping chamber 52 to return to the primary oil-mist
trapping chamber 51.
[0025] As illustrated in FIGS. 2 and 5, the primary oil-mist
trapping chamber 51 has a bottom surface 51a. The location of the
return port 34 within the chamber 51 is located at a higher level
than (e.g., vertically above) the bottom surface 51a. Thus, the
return port 34 is spaced vertically above and apart from the bottom
surface 51a of the primary oil-mist trapping chamber 51. The
secondary oil-mist trapping chamber 52 has a bottom surface 52a,
and the return port 34 is positioned at substantially the same
level (e.g., same vertical height) as the lowermost portion 52b of
the bottom surface 52a. Unlike the conventional oil separator, the
return port 34 is not located along the bottom surface 51a of the
primary oil-mist trapping chamber 51. That is, the return port 34
is located only along the bottom surface 52a of the secondary
oil-mist trapping chamber 52. The separation plate 31 has a wall
surface 31a facing the primary oil-mist trapping chamber 51. A rib
35 is formed near the return port 34 of the wall surface 31a. In
this embodiment, the rib 35 has a substantially U-shape such that
it prevents the blow-by gas from flowing into the return port
34.
[0026] As illustrated in FIG. 2, the upper base 40 is a cover
member sized and shaped to cover the separation plate 31 of the
middle base 30. The primary oil-mist trapping chamber 51 is
disposed between the upper base 40 and the separation plate 31.
[0027] As illustrated in FIG. 2, the lower base 10, the middle base
30, and the upper base 40 are assembled to each other by vibration
welding, etc. The liquid oil trapping chamber 50 and the secondary
oil-mist trapping chamber 52 above the liquid oil trapping chamber
50 are positioned between the lower base 10 and the middle base 30.
The liquid oil trapping chamber 50 and the secondary oil-mist
trapping chamber 52 are defined by partitions of the lower base 10
and the middle base 30. The primary oil-mist trapping chamber 51 is
positioned between the middle base 30 and the upper base 40. The
liquid oil trapping chamber 50 is a space that traps large particle
size liquid oil (not illustrated) contained in the blow-by gas.
[0028] As illustrated in FIG. 2, the primary oil-mist trapping
chamber 51 is located above the liquid oil trapping chamber 50. The
primary oil-mist trapping chamber 51 is hence located downstream of
the liquid oil trapping chamber 50 in a flow passage for the
blow-by gas. The primary oil-mist trapping chamber 51 is a space
that traps small particle size oil mist contained in the blow-by
gas. The secondary oil-mist trapping chamber 52 is located at
substantially the same vertical level (e.g., same vertical height)
as the primary oil-mist trapping chamber 51, and it is adjacent to
the primary oil-mist trapping chamber 51 in the horizontal
left-to-right direction. The primary oil-mist trapping chamber 51
is separated from the secondary oil-mist trapping chamber 52 by the
separation plate 31 of the middle base 30. The secondary oil-mist
trapping chamber 52 is located downstream of the primary oil-mist
trapping chamber 51 in the flow passage of the blow-by gas. The
secondary oil-mist trapping chamber 52 is a space that traps small
particle size oil mist contained in the blow-by gas.
[0029] The lower base 10, the middle base 30, and the upper base 40
illustrated in FIGS. 1 and 2 are different members made of rigid
synthetic resin such as polypropylene. The oil separator 1 may be
attached in the middle of a flow passage (not illustrated) that
connects a crankcase (not illustrated) to an air-intake duct (not
illustrated). For example, attaching portions 20 of the lower base
10 and attaching portions 36 of the middle base 30 are each
attached to a corresponding component forming the flow passage via
a metal collar (not illustrated).
[0030] As illustrated in FIGS. 2 and 5, the first flow inlet 11 and
the second flow inlet 12, which are formed in the lower region of
the lower base 10, each communicate with the flow passage in the
crankcase. As a result, when the blow-by gas flows from the
crankcase, it enters through the first flow inlet 11 and/or the
second flow inlet 12 into the liquid oil trapping chamber 50. The
blow-by gas, which thereby flows into the liquid oil trapping
chamber 50, then collides with not only interior wall 10c of the
recess 10a of the lower base 10, but also collision walls 14, 15,
16, 17 and the interior surface of the middle base 30.
[0031] As illustrated in FIG. 2, the first collision wall 14
extends upward from an intermediate region of the recess 10a
between the flow inlets 11, 12 in the left-to-right direction. The
collision wall 14 extends upward and obliquely above the first flow
inlet 11. The second collision wall 15 extends obliquely below and
inward in the horizontal direction from a right side of the
interior wall 10c. The third collision wall 16 extends inward in
the horizontal direction from a left side of the interior wall 10c.
The third collision wall 16 extends substantially parallel to the
first collision wall 14, and is positioned above the first
collision wall 14. The fourth collision wall 17 is located above
the third collision wall 16, and extends obliquely upward and
rightward from an intermediate portion of the collision wall 16. In
this manner, the collision wall 17 forms the right portion of a
bottom surface of the secondary oil-mist trapping chamber 52. The
collision wall 18 extends continuously leftward and upward from the
collision wall 17 to form a left portion of the bottom surface of
the secondary oil-mist trapping chamber 52. The collision wall 18
extends obliquely upward and leftward from the collision wall 17 to
connect with a left side of the interior wall 10a. The sixth
collision wall 19 extends downward from an upper wall surface of
the interior wall 10a.
[0032] As illustrated in FIG. 2, the large particle size liquid oil
contained in the blow-by gas collides with the interior wall 10c,
the collision walls 14, 15, 16, 17, and the interior surface of the
middle base 30, and thereby adheres to the corresponding surfaces.
The large particle size liquid oil adhered to the interior wall
10c, collision walls 14, 15, 16, 17, and the interior surface of
the middle base 30 drops under its own weight (via gravity), and
accumulates on the bottom surface 50a of the liquid oil trapping
chamber 50. The accumulated liquid oil then flows through the flow
inlets 11, 12 and is collected. As a result, the liquid oil
trapping chamber 50 serves to trap the large particle size liquid
oil contained in the blow-by gas.
[0033] Referring to FIG. 2, the blow-by gas flows from the liquid
oil trapping chamber 50, through the first communication port 32,
and into the primary oil-mist trapping chamber 51. The blow-by gas
collides with the wall surface 31a of the separation plate 31 and
an interior surface of the upper base 40, etc. The small particle
size oil mist contained in the blow-by gas collides with the
surfaces and adheres thereto. The small particle size oil mist
adhered to the wall surface 31a, etc. drops due under its own
weight (via gravity), and then accumulates on the bottom surface
51a of the primary oil-mist trapping chamber 51. The small particle
size oil mist subsequently returns to the liquid oil trapping
chamber 50 through the first communication port 32, and then is
collected together with the large particle size liquid oil. Thus,
the primary oil-mist trapping chamber 51 serves to trap the small
particle size oil mist contained in the blow-by gas.
[0034] Referring to FIG. 2, the blow-by gas flows from the primary
oil-mist trapping chamber 51 through the second communication port
33 into the secondary oil-mist trapping chamber 52. Here, the
blow-by gas collides with each of the wall surfaces in the
secondary oil-mist trapping chamber 52. For example, the blow-by
gas collides with the interior wall 10c of the recess 10a of the
lower base 10 within the chamber 52, as well as each of the
collision walls 17, 18, 19, and a back surface 31b of the
separation plate 31, etc. The small particle size oil mist
contained in the blow-by gas collides with the surfaces and adheres
thereto. The small particle size oil mist adhered to the surfaces
drops under its own weight (via gravity), and then accumulates on
the bottom surface 52a of the secondary oil-mist trapping chamber
52. The small particle size oil mist returns to the primary
oil-mist trapping chamber 51 through the return port 34, and is
collected together with the small particle size oil mist trapped in
the primary oil-mist trapping chamber 51. Thus, the secondary
oil-mist trapping chamber 52 serves to trap the small particle size
oil mist contained in the blow-by gas.
[0035] As illustrated in FIG. 2, a flow outlet 13 is formed on the
upper right region of the lower base 10. The flow outlet 13
communicates with the communication flow passage of the air-intake
duct. Therefore, the blow-by gas flown into the oil separator 1
flows from the secondary oil-mist trapping chamber 52 through the
flow outlet 13 in the air-intake duct. As described above, as
blow-by gas flows into the oil separator 1, large particle size
liquid oil and small particle size oil mist contained in the
blow-by gas are separated from the blow-by gas and discharged out
of the flow inlets 11, 12. In this way, small particle size liquid
oil and oil mist are prevented from flowing from the flow outlet 13
of the oil separator 1 into the air-intake duct. As a result, the
blow-by gas without the liquid oil and oil mist that were initially
input into the separator 1, can be returned as an output from the
separator 1 to the internal combustion engine located downstream of
the oil separator 1, to be combusted again in the internal
combustion engine.
[0036] As described above, the oil separator 1 includes a plurality
of oil-mist trapping chambers, for example, a primary oil-mist
trapping chamber 51 and a secondary oil-mist trapping chamber 52.
Therefore, the total length traversed by the blow-by gas passage
within the oil separator 1 is relatively long. Such a long length
flow passage through the oil separator offers the potential to
enhance the efficiency at which the small particle size oil mist
contained in the blow-by gas is trapped.
[0037] As illustrated in FIG. 2, the return port 34 allows the oil
mist trapped in the secondary oil-mist trapping chamber 52 to be
returned into the primary oil-mist trapping chamber 51. The first
communication port 32 allows the oil mist trapped in the secondary
oil-mist trapping chamber 52 and the oil mist trapped in the
primary oil-mist trapping chamber 51 to be returned into the liquid
oil trapping chamber 50. The flow inlets 11, 12 allow the
above-described oil mist and the liquid oil trapped in the liquid
oil trapping chamber 50 to be discharged. In this way, both oil
mist and liquid oil can be collected. Therefore, it is possible to
collect trapped oil mist with the secondary oil-mist trapping
chamber 52 without providing a dedicated collecting passage,
thereby reducing the amount of structural components needed. In
addition, the small particle size oil mist can be efficiently
trapped and the size of the oil separator 1 can be reduced.
[0038] As described above, the oil separator 1 includes a
separation plate 31, an upstream oil-mist trapping chamber (primary
oil-mist trapping chamber 51), and a downstream oil-mist trapping
chamber (secondary oil-mist trapping chamber 52) as illustrated in
FIG. 2. The trapping chambers are divided by the separation plate
31 and arranged adjacent to each other in the left-to-right
direction. The upstream oil-mist trapping chamber 51 fluidly
communicates with the flow inlets 11, 12 for blow-by gas via the
liquid oil trapping chamber 50. The downstream oil-mist trapping
chamber 52 fluidly communicates with the upstream oil-mist trapping
chamber 51, as well as with the flow outlet 13 for blow-by gas. A
return port 34 is formed on the separation plate 31, serving to
return the oil mist trapped in the downstream oil-mist trapping
chamber 52 to the upstream oil-mist trapping chamber 51. The return
port 54 is located at a position vertically above the bottom
surface 51a of the upstream oil-mist trapping chamber 51 and is
positioned at substantially the same vertical height as the
lowermost portion of the bottom surface 52a of the downstream
oil-mist trapping chamber 52.
[0039] The oil contained in blow-by gas is separated from the
blow-by gas by the separator 1, and gathers as droplets in both the
upstream oil-mist trapping chamber 51 and the downstream oil-mist
trapping chamber 52. The oil that drops and accumulates in the
downstream oil-mist trapping chamber 52 passes through the return
port 34 and is allowed to return to the upstream oil-mist trapping
chamber 51. On the other hand, the oil that drops and accumulates
in the upstream oil-mist trapping chamber 51 is not allowed to flow
through the return port 34 into the downstream oil-mist trapping
chamber 52. Consequently, liquid oil is not accumulated in the
downstream oil-mist trapping chamber 52, and as a result, the
separated liquid oil is prevented from flowing out of the
downstream oil-mist trapping chamber 52 through the flow outlet 13
so as to be discharged outside of the oil separator 1. As a result,
the liquid oil can be prevented from flowing to a device(s) such as
an internal combustion engine positioned downstream of the oil
separator 1 and from being combusted again in the internal
combustion engine. In this way, the failure of a device(s) located
downstream of the oil separator 1 can be prevented.
[0040] As illustrated in FIG. 2, the separation plate 31 includes
the wall surface 31a facing opposite to the upstream oil-mist
trapping chamber 51. The rib 35 is formed in the vicinity of the
return port 34 at the wall surface 31a so that the rib 35 prevents
blow-by gas from flowing into the return port 34. Therefore,
blow-by gas is prevented from flowing from the upstream oil-mist
trapping chamber 51 into the downstream oil-mist trapping chamber
52 through the return port 34. Thus, the blow-by gas tends not to
flow through the return port 34 but through the communication port
33, which helps to flow the gas from the upstream oil-mist trapping
chamber 51 into the downstream oil-mist trapping chamber 52.
[0041] As illustrated in FIGS. 2 and 3, the rib 35 has a
substantial U-shaped configuration. For example, the rib 35 extends
circumferentially as an arc around the return port 4. Therefore,
the blow-by gas is prevented from flowing from the upstream
oil-mist trapping chamber 51 through the return port 34 into the
downstream oil-mist trapping chamber 52.
[0042] As illustrated in FIGS. 2 and 3, the rib 35 has a right
portion standing upright between the return port 34 and the first
communication port 32. Therefore, the right portion of the rib 35
prevents the blow-by gas from directly flowing from the first
communication port 32 into the return port 34. The rib 35 has an
upper portion extending from the right portion along the upper edge
of the return port 34 and a lower portion extending from the right
portion along the lower edge of the return port 34. As a result,
the blow-by gas is more reliably prevented from flowing directly
into the return port 34 from the first communication port 32, and
rather flows around the return port 34.
[0043] The rib 35 has a substantially U-shape as illustrated in
FIG. 2. Alternatively, the rib 35 may have various other shapes
such as a substantially V-shape or a horseshoe shape, to deflect
the gas from flowing into the return port 34. The rib has
preferably a shape that obtains the same effect as that of the
substantially U-shaped rib 35.
[0044] As described-above, the lower base 10, the middle base 30,
and the upper base 40 are made of resin. Alternatively, the lower
base 10, the middle base 30, and the upper base 40 may be made of
separate metal members that are integrally connected. Such a metal
oil separator generally has a higher strength and heat resistance
as compared to the resin oil separator 1. As described-above, the
lower base 10, the middle base 30, and the upper base 40 are made
as separate members. Alternatively, two or all of these bases may
be formed in one member.
[0045] As described-above, the oil separator 1 has two oil-mist
trapping chambers 51, 52. Alternatively, the oil separator 1 may
have more than two oil-mist trapping chambers.
[0046] The various examples described above in detail with
reference to the attached drawings are intended to be
representative of the present disclosure and are thus non limiting
embodiments. The detailed description is intended to teach a person
of skill in the art to make, use and/or practice various aspects of
the present teachings and thus does not limit the scope of the
disclosure in any manner. Furthermore, each of the additional
features and teachings disclosed above may be applied and/or used
separately or with other features and teachings in any combination
thereof, to provide improved oil separators, and/or methods of
making and using the same.
* * * * *