Internal-combustion engines – Charge forming device – Crankcase vapor used with combustible mixture
Reexamination Certificate
2001-07-11
2002-08-13
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Crankcase vapor used with combustible mixture
Reexamination Certificate
active
06431159
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oil separator structure for use in separating oil contained in blow-by gas exhausted from an internal combustion engine, and more particularly, to both an arrangement and a construction of an oil separator chamber.
2. Description of the Background Art
As one example of the oil separator of the conventional internal combustion engine, there is provided an oil separator disclosed in the gazette of Japanese Examined Utility Model Publication No. Hei 6-27778. As shown in
FIG. 9
of the perspective view showing an exploded state, a frame-like outer circumferential wall
06
projected outwardly is integrally arranged in cooperation with a sidewall
05
ranging from a lower part of a vertical wall of a cylinder block
01
to a skirt segment in an oil separator
03
installed at an outside segment of the cylinder block
01
. A lid plate
07
is connected to the outer circumferential wall
06
. Thereby, an oil separator chamber
04
is formed by the cylinder block side wall
05
, the outer circumferential wall
06
and the lid plate
07
.
Although a plurality of oil baffles
013
,
014
are arranged within this oil separator chamber
04
so as to cause its inner side to become a labyrinth, the outer circumferential wall
06
is arranged to enclose a part of the reinforcing rib
015
of the cylinder block
01
. This reinforcing rib
015
is constituted as one oil baffle
013
within the oil separator chamber
04
. As shown in
FIG. 9
, another oil baffle
014
is cooperatively arranged within a predetermined range of the sidewall
05
of the cylinder block
01
. Then, both a blow-by gas intake port
011
and a blow-by gas exhaust port
012
are arranged at positions where these oil baffles
013
,
014
are held. The blow-by gas intake port
011
is formed at the cylinder block sidewall
05
in a punched-out shape and the blow-by gas exhaust port
012
is formed at the lid plate
07
.
In addition, the oil separator disclosed in the gazette of Japanese Patent Laid-Open No. Sho 61-138811 as another example of the oil separator of the conventional internal combustion engine is constructed such that a side surface of the cylinder head
021
is provided with a cap
026
for sealingly closing a cam shaft mounting space
023
of a four-stroke engine of a type in which a cam shaft
022
is pivotally supported at the cylinder head
021
as shown in FIG.
10
. The cam shaft
022
is driven by a sprocket
024
and a chain
025
or the like installed between it and a crank shaft (not shown).
The cap
026
is formed by a hollow member and at the same time its inner space
027
is communicated with the crank chamber and the surrounding atmosphere to act as a breather chamber. That is, the cap
026
is formed with both a gas inlet
029
communicating the inner space
027
with a cam shaft mounting space
023
, and an oil return hole
030
communicated with a chain tunnel
028
. The upper segment of the cap
026
is provided with a surrounding atmosphere communication hole
031
communicating the inner space
027
with the surrounding atmosphere. In addition, ribs
032
,
032
alternatively projecting from both its inner wall and outer wall are formed in the inner space
027
to constitute a labyrinth for gas flowing in the inner space
027
.
In the aforesaid oil separator of the conventional internal combustion engine, the oil separator was formed by assembling the baffle plates or lid plate, and cap or the like to composing members of the internal combustion engine such as the cylinder block or the cylinder head and the like, so that this prior art had a problem that the number of component elements and the number of assembling steps are increased.
SUMMARY OF THE INVENTION
In order to solve the aforesaid problem, the oil separator structure of the internal combustion engine of the present invention is characterized in that an oil separating chamber for separating oil contained in blow-by gas is arranged outside a transmission member passage connecting a crank shaft with a cam shaft of a valve system and at an abutting surface between a cylinder block and a cylinder head. Partition walls are alternatively arranged at the cylinder block and the cylinder head perpendicular to the abutting surface for dividing the oil separating chamber into a plurality of small subchambers to form a labyrinth structure. The small subchamber at one end of the plurality of small subchambers is provided with a blow-by gas intake passage communicated with the transmission member passage. The small subchamber at the other end of the plurality of small subchambers is provided with a blow-by gas exhaust passage for returning blow-by gas to an air cleaner. Each of the small subchambers not provided with the blow-by gas intake passage is provided with an oil return passage communicating with the transmission member passage.
The present invention is constructed as described above and the oil separator structure is formed under utilization of an abutting surface between the cylinder block and the cylinder head of the basic structural members of the internal combustion engine, so that the number of component elements and the number of assembling steps are reduced as compared with the prior art, and so the costs become less expensive.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 5123385 (1992-06-01), Sado et al.
patent: 5261380 (1993-11-01), Romano
patent: 5542402 (1996-08-01), Lee et al.
patent: 5617834 (1997-04-01), Lohr
patent: A61138811 (1986-06-01), None
patent: Y2627778 (1994-07-01), None
Nishi Tohru
Oike Ken
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
McMahon Marguerite
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