JPH0216005Y2 - - Google Patents

Description

[Detailed description of the invention] ≪Industrial application field≫ This invention relates to an oil separator installed in a rocker cover installed at the upper end of an engine to separate oil in blow-by gas. This invention relates to improvements to oil return passages.

≪Conventional technology≫ In general, engines have gases leaking from the combustion chamber into the crankcase that are returned to the intake passage to remove CO, HC, etc.
A blow-by gas reduction device is provided to prevent unburned gas containing such substances from flowing out into the atmosphere.

The blow-by gas that is returned to the intake passage in this type of reduction device usually contains oil mist, and if it is returned as it is, it will consume a lot of oil, so conventionally an oil separator is installed to separate the oil and gas. An example of this is shown in Japanese Utility Model Application No. 61-51425.

The oil separator disclosed in the same issue is
It is provided in a rocker cover provided above the cylinder head, and has a separator wall hanging from the ceiling wall of the rocker cover and a separator plate attached to the lower end of this separator wall. A serpentine passageway is provided in the separator chamber to promote oil mist separation, but conventional oil separators, including the one shown in this publication, do not require blow-by gas to be introduced into the interior of the separator chamber. At the same time, there was a problem with the return passage that returns the oil separated inside, as explained below.

≪Problems to be solved by the invention≫ In other words, a concave groove is generally provided in the separator plate as a return passage for an oil separator, but this passage is used as the introduction port for blow-by gas into the separator chamber as described above. It also serves as Therefore, if this concave groove is small, the flow velocity when blow-by gas is introduced becomes faster, making it easier to suck in oil. Also, when the engine is operated at high speed and under high load, a large amount of gas is generated, and the amount of oil mist is also reduced. Considering the amount of gas introduced, the amount of oil returned, and the flow velocity when blow-by gas is introduced, the larger the cross-sectional area of the opening, the better. There was a problem.

Therefore, if it is not possible to increase the height, the cross-sectional area of the return passage can be can be made larger.

However, although this configuration increases the cross-sectional area of the return passage, the following problems may occur unless the widths of the groove and the notch are taken into consideration.

In other words, the separator chamber communicates with the intake passage, and the internal pressure becomes negative while the engine is running.
A flow is generated in the direction of sucking the blow-by gas into the separator chamber.

On the other hand, oil is splashed onto the outer surface of the separator wall by the swinging of the rocker arm. Therefore, for example, if the width of the notch is made larger than the width of the groove, the splashed oil will flow down the separator wall, causing the peripheral edge of the separator plate to protrude slightly outward from the outer surface of the separator wall. Therefore, this oil remains on the periphery of the separator plate, and is sucked by the negative pressure to the periphery located inside the notch, increasing the possibility that it will enter the separator chamber.

This idea was made in view of these conventional problems, and it slows down the flow velocity when blow-by gas is introduced into the separator chamber to suppress oil entry. To provide an oil separator for an engine which can prevent oil from entering the separator chamber from the outer surface of the separator wall while sufficiently ensuring oil introduction and oil return from the separator chamber.

<<Means for Solving the Problems>> In order to achieve the above object, this invention provides a separator wall extending downward from the ceiling wall of the rocker cover, and is in contact with the lower end of the separator wall. In an engine in which a separator chamber is formed by providing a separator plate that protrudes outward from the engine to separate oil in blow-by gas, the separator plate has a downwardly recessed oil groove that returns the oil separated in the separator chamber. At the same time, a notch was formed in the separator wall located at the opening of the oil groove, the notch opening facing the oil groove and having a width smaller than the width of the oil groove.

<<Operation>> According to the oil separator having the above configuration, the passage for introducing the blow-by gas into the separator chamber and for returning the oil separated from the gas in the separator chamber is formed by the oil groove provided in the separator plate and the passage for returning the oil separated from the gas in the separator chamber. Since it is formed by a notch provided in the facing separator wall, the blow-by gas can be introduced into the separator chamber without increasing the overall height of the engine, and the flow velocity can be slowed down to prevent oil suction as much as possible. Furthermore, the cross-sectional area necessary to return the blow-by gas generated at high speeds and high loads and the oil separated from this gas is secured.

In addition, since the notch formed in the separator wall is smaller than the width of the oil groove formed in the separator plate, the oil splashed on the outer surface of the separator wall will flow down the wall. , the oil can be reliably dropped into the return oil groove.

<<Example>> Hereinafter, preferred embodiments of this invention will be described in detail with reference to the accompanying drawings.

1 to 3 show an embodiment of an oil separator for an engine according to this invention.

The oil separator shown in FIG.
A rocker cover 14 is attached to the upper end with a gasket 12 interposed therebetween, and defines a valve operating chamber 16 above the cylinder head 10.

A camshaft 18 is disposed within the valve operating chamber 16 along the direction in which the cylinders are arranged.
A pair of rocker arm shafts 24, 24 each having a rocker arm 22 which is swung by a cam 20 to open and close the intake valve is provided above the rocker arm shaft 8.

And above the Rotsuka armshaft 24,
An oil separator 26 is arranged to separate oil mist in blow-by gas flowing into the valve train chamber 16 from a crank chamber (not shown).

The oil separator 26 includes a separator wall 28 hanging downward from the ceiling wall 14 a of the rocker cover 14 and a separator plate 30 disposed at the lower end between the separator walls 28 . A separator chamber 34 is defined by abutting and fixing the lower end of the separator chamber 34 .

Details of separator wall 28 are shown in FIG.

The separator wall 28 includes a substantially rectangular outer peripheral wall 28a that is offset laterally from the center of the rocker cover 14 and extends along the cylinder arrangement direction;
A plurality of reinforcing walls 28b, 28b... provided perpendicular to the longitudinal direction of a, and an outer peripheral wall 28a.
An annular wall 28c for mounting an oil cap is provided so as to be inscribed with the long side of the oil cap.

The outer peripheral wall 28a and the annular wall 28c have a height such that their lower ends abut against the upper surface of the separator plate 30, and the reinforcing wall 28b is the second wall from the left in the figure (28b'). Only the reinforcing wall 28 comes into contact with the separator plate 30, and the rest of the reinforcing wall 28
b is shortened so as to be spaced apart from the upper surface of the separator plate 30.

Further, two concave notches 28d are provided at a predetermined interval on the long side of the outer peripheral wall 28a on the side close to the peripheral wall 14b of the rocker cover 14, and a similar notch is provided in the annular wall 28c. 2
8d' is provided at one location.

With the above configuration, when the separator plate 30 is attached to the separator wall 28, the separator chamber 3
4 is divided into a first chamber 34a including an annular wall 28c and a second chamber 34b other than this, and the first chamber 34a
A blow-by gas intake port 36 that communicates with the engine intake passage through a PCV valve (not shown) opens in the second chamber 34b, and a fresh air intake port 38 that communicates with an air cleaner (not shown) opens in the second chamber 34b. are doing.

Details of the separator plate 30 are shown in FIG.

The separator plate 30 includes the outer peripheral wall 28a.
It has approximately the same planar shape as the one shown in FIG. L-shaped buff-full plates 40 are protruded from the upper surface side at predetermined intervals and perpendicular to the longitudinal direction.

The baffle plate 40 is spaced apart from the ceiling wall 14a in the installed state, and forms a blow-by gas passage that meanders in the vertical direction in the separator chamber 34 with the reinforcing wall 28b facing the baffle plate 40.

In addition, the separator plate 30 is provided with a through hole 30b at a position corresponding to the annular wall 28c, and has first and second through holes 30b for returning the oil mist separated in the separator chamber 34 to the valve operating chamber 16. Oil grooves 30c and 30d are provided.

These oil grooves 30c and 30d have a V-shaped cross section, and the first oil groove 30c is located in the first chamber 34a of the separator chamber 34 and is bent into a substantially L-shape, with an opening 30c at one end thereof. ' is the through hole 30
b, and the opening 30 is located at the periphery of the opening 30 from the other end side.
The groove depth is inclined so that it gradually becomes deeper toward c′.

The second oil groove 30d is connected to the separator chamber 3.
The openings 30d' at both ends of the second chamber 34b of the separator plate 30 are bent into a concave shape.
The grooves are located on the long sides of the grooves and are inclined so that the depth of the grooves gradually increases from the center of the concave shape toward the respective openings 30d and 30d'.

The respective openings 30c' and 30d' of the oil grooves 30c and 30d are set at positions facing the notches 28d' and 28d of the separator wall 28 in the installed state.

Then, each opening 3 of the oil grooves 30c and 30d
The widths W ₁ ′, W 1 of 0c′, 30d _′ are the widths of the notches 28d′, 2
It is larger than the notch widths W ₂ ′ and W ₂ of 8d.

Oil separator 26 configured as above
In this case, when the engine is running at low speed and under low load, blow-by gas is returned to the intake passage from the first chamber 34a of the separator chamber 34 via the PVC valve,
At the time of high speed and high load, blow-by gas is also returned from the second chamber 34b to the intake passage via the fresh air intake port 38 and the air cleaner.

The oil mist separated from the blow-by gas in each of the separator chambers 34a and 34b is separated from the outer peripheral wall 28a, the reinforcing wall 28b, and the buttful plate 4.
0 and flows down onto the separator plate 30, passes through the oil grooves 30c and 30d, and is discharged into the valve operating chamber 16 from the respective openings 30c' and 30d'.

In this case, especially at high speeds and high loads, a large amount of blow-by gas and oil mist is generated, but the passage for introducing the blow-by gas with mist into the separator chamber 34 is the V-shaped opening 30c', 3
0d' and concave notches 28d' and 28d, the cross-sectional area is large, which allows the introduction speed of blow-by gas to be slowed down, and also prevents the oil separated in the separator chamber 34 from being removed at high speeds and high loads. It is possible to make a sufficient return and ensure that sufficient blow-by gas is introduced.

In addition, as the engine is driven, the rocker arm 2
2 is also swung, and as a result, oil is splashed on the outer surface of the outer circumferential wall 28a of the oil separator, and the pressure in the crank chamber becomes relatively higher than that in the separator chamber 34, and blow-by gas is discharged from the valve train chamber 16. This tends to flow into the separator chamber 34 side, and the splashed oil tends to enter the separator chamber 34, but the width W ₂ of the notches 28d, 28d'
W ₂ ' is the opening 30d' of each oil groove 30d, 30c,
Since the width W ₁ and W 1 ' of 30c' is smaller than the width W 1 and W ₁ ', the oil that has flowed down along the outer surface of the outer peripheral wall 28a to the notches 28d and 28d' will surely fall into the oil grooves 30d and 30c. . That is, in the separator for engines such as the invention of the present invention, usually
The outer periphery of the separator plate 30 may be made to protrude outward from the separator wall 28 to prevent a sealing surface from being secured with the separator wall 28 due to dimensional errors, or the outer periphery of the separator plate 30 may be bent downward to 30 is given rigidity to ensure sealing performance.

However, such a separator plate 30
In this structure, as described above, the splashed oil flows down the separator wall 28, the oil accumulates on the outer periphery of the plate 30, and this accumulated oil flows back into the intake system by blow-by gas. There is a problem with doing so. In this case, the blow-by gas flows through the notches 28d and 28 of the separator wall 28.
d' and the oil groove 30c of the separator plate 30,
The oil is sucked into the separator chamber 34 from the opposing portions 30d, and the oil is sucked into the separator chamber 34 through the notches 28d, 28d' and the oil groove 30.
If the widths c and 30d are in the opposite relationship to the present invention, the oil accumulated around the periphery of the plate 30 will easily flow back. In other words, the width of the oil grooves 30c and 30d
The width W ₂ of the notches 28d and 28d' is wider than W 1 and W _{1 '} .
When W ₂ ′ is increased, the upper ends of the outer peripheral edges of the separator plate 30 on both sides of the oil grooves 30c and 30d protrude inward from both ends of the notches 28d and 28d′, and the oil flowing down along the separator wall 28 becomes The oil does not reach the oil grooves 30c and 30d unless it passes through these protruding parts, and the oil passes through the area where the blow-by gas is sucked, so the oil is drawn into the separator chamber 34 by the blow-by gas. However, in the structure of the present invention, the width W ₁ of the oil grooves 30c and 30d,
Since the widths W ₂ and W ₂ ′ of the notches 28d and 28d′ are smaller than W ₁ ′, contrary to the above, the lower end of the separator wall 28 protrudes inward from both ends of the oil grooves 30c and 30d. The separator wall 2
8, the oil flows down through the oil grooves 30c,
When the oil reaches the end of the oil groove 30d, it immediately flows into the groove and can be returned through the oil grooves 30c and 30d without being affected by the suction of blow-by gas.

Note that the widths W ₂ , W ₂ ′ of the notches 28d, 28d′ and the widths W 1 , W ₁ ′ of the openings 30d′, _30c ′ are W ₂ ,
Since it is sufficient that W ₂ ′ is not larger than W ₁ and W ₁ ′, the condition may be such that W ₂ and W ₂ ′ are only slightly smaller than W ₁ and W ₁ ′.

Further, the shape of the notches 28d and 28d' is not limited to a concave shape, but may be a trapezoid, a semicircle, a V-shape, or the like.

Furthermore, in the above embodiment, the separator chamber 34 has two
Although an example is shown in which the engine is divided into two separator chambers, this invention can also be applied to an engine with one separator chamber.

<<Effects of the invention>> As explained in detail in the examples above, according to the engine oil separator according to this invention,
The flow rate of the blow bath gas introduced into the separator chamber is slowed down to suppress oil suction, and while ensuring sufficient return of oil from the separator chamber, it also prevents oil adhering to the outer surface of the separator wall from entering the separator chamber. prevention and promotes separation from blow-by gas oil.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main part of the cylinder head with the rocker cover attached, FIG. 2 is a detailed view of the rocker cover, and FIG. 3 is a detailed view of the separator plate. 10...Cylinder head, 14...Rocker cover, 14a...Ceiling wall, 26...Oil separator, 28...Separator wall, 28d, 28d'...
Notch, 30...Separator plate, 30c,
30d...oil groove, 30c', 30d'...opening, 34...separator chamber.

Claims (1)

[Scope of utility model registration request] A separator chamber is provided with a separator wall extending downward from the ceiling wall of the rocker cover, and a separator plate that contacts the lower end of the separator wall and protrudes outward from the separator wall to separate oil in the blow-by gas. In this engine, a downwardly recessed oil groove for returning oil separated in the separator chamber is formed in the separator plate, and an oil groove facing the oil groove is formed in the separator wall located at the opening of the oil groove. An oil separator for an engine, characterized in that the oil separator has a notch that is open and has a width smaller than the width of the oil groove.