JPH051613Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a blowby gas recirculation device that recirculates blowby gas leaked from the combustion chamber into the crankcase etc. from inside the cylinder head cover to the engine intake system. be.

[Prior art] The blow-by gas that leaks from the combustion chamber into the crankcase through the space between the piston ring and the cylinder not only contains a large amount of unburned gas but also floats inside the crankcase. The oil mist is mixed together. Therefore, the blow-by gas is not directly released into the atmosphere, but is first guided to an oil separation chamber provided at the top of the cylinder head cover. In this oil separation chamber, the oil mist that is scattered and mixed in by the valve rocker arm, etc. when passing through the crankcase or cylinder head cover is separated by adhering to the inner wall surface, etc., and then connected to the blow-by gas outlet. The air is then returned to the intake system via a blow-by gas hose or the like.

As shown in, for example, Japanese Utility Model Application Publication No. 56-132355, the blow-by gas outlet pipe provided in the blow-by gas outlet part is connected to the cylinder head by having one end opening surface close to the inner wall surface of the cylinder head cover. It usually consists of a single piece that fits into the cover. In addition, there is also one in which one end of the blow-by gas outlet pipe has an opening side projecting inward from the inner wall surface of the cylinder head cover.

[Problems to be solved by the invention] However, in the case where one end of the blow-by gas outlet pipe is provided close to the inner wall surface of the cylinder head cover, the oil that falls along the inner wall surface may flow into the outlet pipe. It becomes easier to be carried directly to the opening surface at one end. In addition, in the case where the opening surface of one end of the blow-by gas outlet pipe is protruded inward from the inner wall surface of the cylinder head cover,
When oil adhering to the inner wall surface is carried along the wall surface to the outer periphery of the outlet pipe, it is often carried along the outer periphery to the open end surface by the flow of blow-by gas.

As a result, the extracted oil gets mixed into the blow-by gas again at the opening surface at one end, and is carried along with the blow-by gas from the intake system to the combustion chamber, resulting in contamination of the intake pipe with oil and premature consumption of the oil. It ends up.

The present invention solves this problem in the blowby gas recirculation device by improving the blowby gas outlet part of the cylinder head cover, so that the oil adhering to the inner wall surface of the cylinder head cover is mixed into the blowby gas again and carried away to the intake system. The purpose is to reliably prevent this.

[Means for Solving the Problems] To achieve the above object, the present invention provides a blowby gas recirculation device that recirculates the blowby gas led into the cylinder head cover from the blowby gas outlet to the intake system. a first blow-by gas outlet pipe fitted to the cylinder head cover with the gas outlet part protruding inward from the inner wall surface of the cylinder head cover at one end; and a second blow-by gas outlet pipe fitted into the outlet pipe with a gap on the inner periphery of the blow-by gas outlet pipe, and one end of the first blow-by gas outlet pipe is connected to the opening side of the blow-by gas outlet pipe. It is characterized by having an oil pit hole.

[Function] With this structure, the blow-by gas guided into the cylinder head cover has oil mist removed therein, and then flows to the first blow-by gas fitted into the cylinder head cover. The blowby gas is returned to the intake system from the blowby gas outlet section, which includes a guide pipe and a second blowby gas outlet pipe fitted into the first blowby gas outlet pipe. At that time, even if the extracted oil adhering to the inner wall surface of the cylinder head cover is carried along the outer circumferential surface of the first blow-by gas outlet pipe to its one end opening surface, this one end opening surface Since a second blow-by gas outlet pipe is fitted on the inner periphery of the side with a space between them, the oil entering from the opening surface at one end will be guided into this space. and,
The oil led into this gap is dropped downward from an oil drop hole opened in the gap and drilled in the first blow-by gas outlet pipe.
This makes it difficult for oil to be mixed into the blowby gas discharged from the open end surface of the blowby gas discharge pipe and transported to the intake system.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows a side cross section of a cylinder head cover 1 etc. fixed to the upper end of the cylinder head. An oil separation chamber 2 is formed at the top of the cylinder head cover 1, and within the oil separation chamber 2, there is a passage formed in the cylinder block etc. for blow-by gas leaked from the combustion chamber into the crankcase. It is becoming more and more guided through.

The oil separation chamber 2 is for removing oil mist mixed into blow-by gas inside the crankcase, cylinder head cover 1, etc.
Peripheral wall 3 integrally formed with cylinder head cover 1
A bottom plate 5 is fixed and sealed to the lower end surface 3a of the room and the lower end surfaces 4a of the plurality of partition walls 4, and the interior thereof is formed into a labyrinth-like room by the partition walls 4 and the like. The blowby gas introduced into the oil separation chamber 2 from the blowby gas inlet 6 opened in the bottom plate 5 is mixed into the blowby gas by alternately expanding and contracting, or by reducing its flow rate. The oil mist is extracted by being attached to the inner surface 7a of the side wall 7 of the cylinder head cover 1, the side surface 4b of the partition wall 4, the bottom plate surface 5a, the upper wall surface 2a, etc. The extracted oil passes through the oil outlet 8 formed in the bottom plate 5, the guide groove 5b, etc., and falls from the blow-by gas inlet 6, etc. to the oil pan side.

On the other hand, the blowby gas from which the oil mist has been removed is delivered to a first blowby gas outlet pipe 9 fitted to the side wall 7 of the cylinder head cover 1 and a second blowby gas outlet fitted to the blowby gas outlet pipe 9. The blow-by gas is returned to the intake system little by little through a blow-by gas outlet section 11 that includes a pipe 10.

The first blow-by gas outlet pipe 9 has a cylindrical shape with both ends open, and is fixed to the side wall 7 of the cylinder head cover 1 in a substantially horizontal position. It is made to protrude more inward. That is, a mounting hole 7b communicating with the oil separation chamber 2 is formed in the side wall 7 of the cylinder head cover 1, and the first blow-by gas outlet pipe 9 is inserted into the mounting hole 7b so that one end opening surface 9a of the pipe 9 is connected to the side wall 7. It is press-fitted so as to protrude inward from the inner surface 7a by a required amount. Further, a protruding strip 9c for preventing slippage is formed on the outer end side.
The starting end of a blow-by gas hose 12 that connects the inside of the oil separation chamber 2 and the internal space of the air cleaner is connected to the outer periphery of the outer end thereof.

A second blowby gas deriving pipe 10 is fitted into the blowby gas deriving pipe 9 at a portion of the first blowby gas deriving pipe 9 located within the oil separation chamber 2 . The second blow-by gas derivation pipe 10 has a gap S on the inner periphery of the opening surface 9a side of one end of the first blow-by gas derivation pipe 9.
The outer end 10a of the first blow-by gas outlet pipe 9 is press-fitted into the first blow-by gas outlet pipe 9 and fixed, and the inner end 10b is inserted from the one end opening surface 9a of the first blow-by gas outlet pipe 9. Furthermore, the required length l protrudes inward (the protrusion size l
is the inner diameter d of the first blow-by gas outlet pipe 9
(preferably about 1/3 to 2/3 of that), and a wide-mouthed blow-by gas outlet 13 is formed at its edge. Specifically, by providing a continuous constricted portion 10c between the outer end 10a and the inner end 10b of the second blowby gas delivery pipe 10, the first blowby gas delivery pipe 9 The above-mentioned gap S is formed which continues from the opening surface 9a at one end to the outer end 10a of the second blow-by gas outlet pipe 10.

Then, an opening is made between this gap S and the outer periphery of the first blow-by gas outlet pipe 9 with a small diameter r (approximately 1/5 to 1/5 of the inner diameter d of the first blow-by gas outlet pipe 9).
An oil drop hole 14 of approximately 1/4 of the diameter is provided. A plurality of oil pit holes 14 are provided circumferentially from one end opening surface 9a of the first blow-by gas outlet pipe 9.

With such a configuration, the blowby gas from which oil mist has been removed in the oil separation chamber 2 is connected from the blowby gas outlet 13 to the second blowby gas outlet pipe 10 or the first blowby gas outlet pipe 9. The air is guided through the blow-by gas hose 12 to the internal space of the air cleaner that forms the starting end of the intake system, and from the intake system to the combustion chamber again. And the blow-by gas reflux amount is
It is suppressed to an appropriate value by the throttling action of the throttling portion 10c of the second blow-by gas outlet pipe 10.

In this way, the blowby gas is refluxed, and as described above, this blowby gas reflux device has the first blowby gas outlet pipe 9 and the second blowby gas outlet pipe 9 constituting the blowby gas outlet part 11.
A blow-by gas outlet pipe 10 is made to protrude inward from the inner surface 7a of the side wall 7 of the cylinder head cover 1, and a second blow-by gas outlet pipe 9 is provided with a gap S on the inner periphery of the opening surface 9a side of one end of the first blow-by gas outlet pipe 9. A blow-by gas outlet pipe 10 is fitted therein. Therefore, the side wall 7 of the cylinder head cover 1
The oil adhering to the inner surface 7a of the
Even if the oil is carried along the outer circumferential surface of the blow-by gas outlet pipe 9 to the opening surface 9a at one end, the oil carried to that part will flow through the oil pit 14 drilled in the upper part and the opening surface 9a at the one end. Said〓
This will lead to an interval S. The oil led into this space S is then passed through the oil pit 1 at the bottom.
4 into the oil separation chamber 2, and then from the oil outlet 8 provided in the bottom plate 5 to the oil pan side.

Therefore, with such a configuration, the oil mist in the blowby gas extracted in the oil separation chamber 2 is mixed into the blowby gas again at the blowby gas outlet 13 and transported to the intake system. This can be avoided. Moreover, the blowby gas outlet 13 formed in the second blowby gas outlet pipe 10 is made to protrude further inward from the one end opening surface 9a of the first blowby gas outlet pipe 9, and is formed to have a wide mouth. are doing. With such a device, the wide-mouthed blow-by gas outlet 13 can function as an oil return to the opposite side of the outlet, so that the oil led into the gap S can be transferred to the blow-by gas outlet 13. It is difficult to get to exit 13. As a result, a problem in which the oil in the blow-by gas once extracted is transported from the blow-by gas outlet 13 to the intake system together with the blow-by gas can be avoided, and oil contamination in the intake pipe and oil being transported to the combustion chamber can be avoided. It is possible to reliably prevent problems that would cause the product to be consumed.

Also, a second blow-by gas outlet pipe 10 is press-fitted into the first blow-by gas outlet pipe 9.
can be easily manufactured by press drawing or drawing from a pipe. By appropriately adjusting the throttle portion 10c during molding, it becomes easy to set the blow-by gas recirculation amount to an optimum amount.

Although one embodiment of the present invention has been described above, the present invention is of course not limited to the above-mentioned embodiment. The protruding dimensions, the shape of the second blow-by gas outlet pipe, etc. are not limited to the shape shown in the figure, and various modifications can be made.

[Effects of the invention] In the present invention as described in detail above, one end of the first blow-by gas outlet pipe is made to protrude inward from the inner wall surface of the cylinder head cover, and the inner periphery of this one end is made to protrude inward from the inner wall surface of the cylinder head cover. 〓Insert the second blow-by gas outlet pipe with a gap between the 〓
During this time, the oil carried to the outer peripheral surface of the first blow-by gas outlet pipe is guided and dropped. Therefore, the problem of the oil in the blow-by gas extracted in the oil separation chamber getting mixed into the blow-by gas again and being carried to the intake system is reliably eliminated, ensuring that oil contamination in the intake pipe and early consumption of oil are prevented. can be prevented.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a partially omitted longitudinal sectional view, FIG. 2 is a bottom view of the cylinder head cover, and FIG. 3 is a plan view of the bottom plate. 1... Cylinder head cover, 2... Oil separation chamber, 5... Bottom plate, 6... Blow-by gas inlet, 7... Side wall, 7a... Inner wall surface (inside side wall),
8... Oil outlet, 9... First blow-by gas outlet pipe, 9a... One end opening surface, 10... Second blow-by gas outlet pipe, 10a... Outer end, 11... Blow-by gas outlet Department, S...〓
Interval, 14...Oil pit.

Claims (1)

[Scope of utility model registration request] In a blowby gas recirculation device that recirculates blowby gas led into a cylinder head cover from a blowby gas outlet to an intake system, one end of the blowby gas outlet has an opening side protruding inward from an inner wall surface of the cylinder head cover. A first blow-by gas outlet pipe fitted to the cylinder head cover, and a second blow-by gas outlet pipe fitted into the outlet pipe with a space between the inner periphery of the first blow-by gas outlet pipe on the opening surface side at one end. A blow-by gas recirculation device comprising: a gas lead-out pipe; and an oil drop hole communicating with the gap is provided on one end opening side of the first blow-by gas lead-out pipe.