JPS643766Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a blow-by gas breather passage in an internal combustion engine that mainly vents blow-by gas leaking from a combustion chamber into a crankcase through a gap between a piston and a cylinder wall.

PRIOR ART In general, in the case of a gasoline engine, as shown in FIG. 6, blow-by gas accumulated in a crankcase 1 is sent into a cam chamber 3 through a breather passage 2, and the blow-by gas in the cam chamber 3 is transferred to a ventilation area. PCV controlled by manifold negative pressure
The fuel is fed into the intake manifold 6 through the valve 4, sucked into the engine, and re-combusted. FIG. 6 shows the case of a V-type engine, in which 7 indicates a cylinder head, 8 indicates a head cover, 9 indicates an oil pan, and 10 indicates an oil passage. Further, in the figure, black arrows indicate the flow of blow-by gas, white arrows indicate the flow of fresh air taken in from the air cleaner 5, and dotted arrows indicate the flow of blow-by gas when the air cleaner is fully opened.

In such a gasoline engine, the breather passage 2 is provided along the side of the cylinder head 7, as shown in FIG. 7, and is designed so that its opening is close to the wall of the cam chamber 3. There are, but
In this type of product, the camshaft 1 is in the cam chamber 3.
1 or the rocker arm (not shown) flows into the breather passage 2 directly or along the wall surface of the cam chamber 3, thereby reducing the substantial ventilation area of the breather passage 2. However, there is a problem in that the ventilation of blow-by gas is obstructed, the pressure inside the crankcase increases, and oil return becomes difficult.

Therefore, in the past, a head cover gasket was protruded above the opening of the breather passage to the cam chamber to cover the opening and prevent the oil from being blown up from the crank chamber along with the blow-by gas. Jikko 54-
(See Publication No. 45461). However, with this method, the head cover mounting part is located relatively high in the cam chamber, so it is not possible to completely prevent oil splashing from the cam and rocker arm from entering the breather passage. There is.

Purpose This invention was made taking the above points into consideration.
To provide a blow-by gas breather passage which prevents oil droplets scattered in a cam chamber from jumping into the breather passage or flowing along a wall surface with a simple structure.

Configuration In order to achieve the object of the present invention, a cover is provided over the breather passage that opens near the wall of the cam chamber.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the blow-by gas breather passage according to the present invention, as shown in FIG. A cover part 13 is provided at the top of the cylinder head 7 and covers the opening of the breather passage 2 which protrudes from the cam case 12 and is integrally formed. In the figure, 14 indicates a head cover. Further, a cam chamber 3 is formed surrounded by the cylinder head 7, cam case 12, and head cover 14. The length of the breather passage 2 is the cylinder head 7.
It is regulated by the height of the pipe, the oil passage, etc.

As shown in FIG. 2, this cover part 13 sufficiently covers the upper part of the opening of the breather passage 2, and
In addition to preventing the oil droplets O that are scattered inside from flying in, the downwardly sloping protruding portion a that protrudes forward keeps the oil droplets O that have fallen onto the cover portion 13 away from the opening of the breather passage 2. It is formed so that it flows everywhere.
In addition, the cover portion 13, as shown in FIG.
It is formed in a U-shape in cross section, and the flanges B on both sides sufficiently cover the upper sides of the opening in the breather passage 2 to prevent oil droplets O from flowing along the wall surface of the cam chamber 3 into the opening. That's what I do. Note that in FIGS. 1 to 3, arrows indicate the flow of oil droplets O.

Furthermore, FIGS. 4 and 5 show an embodiment in which the head cover 15 is provided directly on the cylinder head 16 without providing a cam case as in the case of FIG. A cover part 1 that extends a part of the head 16 into a canopy shape and completely covers the opening of the breather passage 2.
I am trying to set up 7.

Effects As described above, the blow-by gas breather passage according to the present invention opens near the cam case wall of the cam chamber and at the top of the cylinder head to vent the blow-by gas in the crankcase to the cam chamber through the cylinder head. A cover part having a special shape having a downwardly sloping protruding part that closely covers the upper part of the opening in the breather passage and a flange part that covers the side is provided at the lower part of the cam case and protrudes laterally from the cam case wall part. It has the excellent advantage of being able to effectively prevent oil droplets scattered inside the cam chamber from jumping into the breather passage or flowing along the wall surface due to its simple structure. ing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a cam chamber and a breather passage portion in an internal combustion engine showing an embodiment of a blow-by gas breather passage according to the present invention, and FIG.
FIG. 3 is a cross-sectional view corresponding to the line A-A in the figure, FIG. 3 is a cross-sectional view corresponding to the line B-B, and FIG. 4 is a cam chamber and breather passage portion in an internal combustion engine showing another embodiment of the present invention. , FIG. 5 is a cross-sectional view taken along line C-C in FIG. 4, FIG. 6 is a simplified configuration diagram of a V-type engine to explain the flow of blow-by gas, and FIG. 7 is a general FIG. 3 is a cross-sectional view of a cam chamber and a breather passage portion in an internal combustion engine. 1... Crank case, 2... Breather passage,
3...Cam chamber, 4...PCV valve, 7, 16...
... Cylinder head, 8, 14, 15 ... Head cover, 11 ... Camshaft, 12 ... Cam case, 13, 17 ... Cover part.

Claims (1)

[Scope of utility model registration request] A cover part is installed at the bottom of the cam case near the wall of the cam case through which blow-by gas in the crankcase is vented into the cam chamber through the cylinder head, and which closely covers the upper part of the opening in the breather passage that opens at the top of the cylinder head. The cover has a downwardly sloping protruding portion that is integrally molded to protrude laterally from the cam case wall and directs oil droplets that have fallen on the cover away from the opening of the breather passage, and a breather. A blow-by gas breather passage having a flange portion covering an upper side of an opening of the passage.