JP2003013722A - Blow-by gas reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress oil accumulated in the exposed portion of a female screw part for installing a PCV valve formed in the passage wall surface of a passage for passing blow-by gas from recirculating into an intake passage. SOLUTION: This blow-by gas reducing device comprises a passage 32 formed in the component member 20 of an internal combustion engine and the PCV valve 40 installed on the component member 20. The PCV valve 40 comprises a male screw part 45 threadedly engaged with the female screw part 35 formed in the passage wall surface 32a of the passage 32 and an inflow pipe 44. The inflow pipe 44 is projected from the male screw part 45, positioned in the upstream of blow-by gas flow in the passage 32, extended beyond the exposed portion 35a of the female screw part 35, and disposed on the inside of the passage wall surface 32a including the exposed portion 35a through an annular space 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas returning device for returning blow-by gas to an intake passage of an internal combustion engine via a PCV (Positive Crankcase Ventilation) valve.

[0002]

2. Description of the Related Art In an internal combustion engine, a blow-by gas reducing device is provided in order to recirculate blow-by gas in a crank chamber to an intake passage and suck it back into a combustion chamber for combustion. In this blow-by gas reduction device, in order to prevent the oil mixed in the blow-by gas from flowing into the intake passage and preventing the inconvenience of adhering to the device provided in the intake passage and the increase in oil consumption, A breather chamber for separating the oil in the blow-by gas is provided, and the recirculation amount of the blow-by gas recirculated to the intake passage is adjusted according to the intake negative pressure in accordance with the generation amount of the blow-by gas.
A CV valve is provided.

A blow-by gas reducing apparatus equipped with this type of PCV valve is disclosed, for example, in Japanese Patent Application No. 2000-326062 filed by the present applicant. This PC
The V valve has a bracket that forms the breather chamber
It is attached to the V-valve via a connecting pipe for introducing blow-by gas. The connection pipe has a male screw portion threadedly engaged with a female screw portion formed over a predetermined length from an opening of a communication passage communicating with a breather chamber formed through the bracket. Fixed to.

[0004]

By the way, in the technique disclosed in the above-mentioned application, since the female screw portion of the communication passage is formed longer than the length of the male screw portion of the connecting pipe, the male screw portion of the connecting pipe is formed. In the screwed state, a part of the female screw portion is an exposed portion that is exposed in the communication passage. Therefore, when the oil in the blow-by gas adheres to the passage wall surface of the communication passage, the adhered oil easily stays in the exposed portion where the screw is cut,
There was a problem that the accumulated oil was sucked into the PCV valve and returned to the intake passage.

The present invention has been made in view of such circumstances, and the invention according to claims 1 to 5 is provided with a PCV valve formed on a wall surface of a passage through which blow-by gas flows. The common purpose is to prevent the oil staying in the exposed portion of the female screw portion from flowing back to the intake passage. The invention according to claims 3 and 4 further aims at suppressing the oil adhering to the inflow pipe of the PCV valve from returning to the intake passage, and the invention according to claim 5 is the breather chamber. It is an object of the present invention to prevent the oil attached to the inner wall surface of the tank from flowing into the passage communicating with the PCV valve.

[0006]

According to a first aspect of the present invention, there is provided a passage formed in a component member of an internal combustion engine and a PCV valve attached to the component member, and the blow-by gas is supplied to the blow-by gas. In a blow-by gas returning device that recirculates to an intake passage of the internal combustion engine via a passage and the PCV valve, the PCV valve includes a male screw portion threadedly engaged with a female screw portion formed on a passage wall surface of the passage, and the male screw portion. An inflow pipe projecting from the screw part and extending in the upstream direction with respect to the flow of the blow-by gas in the passage, the inflow pipe being in the passage with the male screw part screwed together. The blow-by gas reduction device is arranged inside the exposed portion of the female screw portion exposed to the outside through an annular gap formed between the female screw portion and the exposed portion.

According to the first aspect of the invention, an annular gap is formed between the inflow pipe forming the inflow passage of the PCV valve for the blow-by gas flowing through the passage and the exposed portion of the female screw portion. Therefore, the intake pressure acting through the PCV valve prevents the oil accumulated in the exposed portion from being sucked from the inflow pipe. Furthermore, since the inflow pipe protrudes from the male screw portion, when the PCV valve is attached to the component, it is inserted into the passage before the male screw portion, and the male screw portion of the PCV valve becomes the female screw portion. It functions as a guide member when screwing.

As a result, the following effects are obtained. That is, since the annular gap is formed between the inflow pipe of the PCV valve and the exposed portion of the female screw portion, the oil retained in the exposed portion is prevented from being sucked from the inflow pipe and recirculates to the intake passage. The amount of oil is reduced. Further, since the inflow pipe protrudes from the male screw portion, the inflow pipe functions as a guide member when the male screw portion of the PCV valve is screwed into the female screw portion when the PCV valve is attached to the component member. Therefore, the workability of attaching the PCV valve to the constituent members is improved.

According to a second aspect of the invention, in the blow-by gas returning apparatus according to the first aspect, the inflow pipe extends beyond the exposed portion in the upstream direction, and the annular shape is formed between the inflow pipe and the passage wall surface. Voids including voids are formed.

According to the second aspect of the present invention, the distance between the female screw portion and the inlet portion of the inflow pipe is increased, and the suction of the oil accumulated in the exposed portion to the PCV valve is further suppressed. . As a result, in the effect of the invention as set forth in claim 1, the distance between the internal thread portion and the inlet portion of the inflow pipe becomes large, and the suction of the oil accumulated in the exposed portion to the PCV valve is further suppressed, and the intake air is reduced. The effect that the amount of oil flowing back to the passage is further reduced is obtained.

According to a third aspect of the present invention, in the blow-by gas returning apparatus according to the first or second aspect, the inflow pipe extends obliquely downward from the male screw portion, and the inlet portion of the inflow pipe is provided. The lower part of the is a projecting portion that extends obliquely downward.

According to the third aspect of the invention, since the inflow pipe extends obliquely downward, the oil adhering to the inner peripheral surface and the outer peripheral surface of the inflow pipe has a lower portion on the inner peripheral surface and the outer peripheral surface. The collected oil flows down the inner peripheral surface and the lower part of the outer peripheral surface to reach the tip of the inlet, and because it is protruding, the area where the oil adheres is small. It easily falls.

As a result, the following effects are exhibited in addition to the effects of the invention described in the cited claims. That is, the oil adhering to the inner peripheral surface and the outer peripheral surface of the inflow pipe easily gathers below the inner peripheral surface and the outer peripheral surface because the inflow pipe extends obliquely downward, and the collected oil is The oil that flows down the inner surface and the outer peripheral surface flows down to the tip of the inlet and easily falls into the passage from the protrusion that forms the lower part of the inlet. The amount of oil that is sucked into the PCV valve is reduced, and the amount of oil that flows back to the intake passage is reduced.

According to a fourth aspect of the present invention, in the blow-by gas returning apparatus according to the third aspect, a water passage communicating with a cooling water passage of the internal combustion engine is formed in the component member immediately below the inflow pipe. The inflow pipe is heated by the cooling water flowing through the water channel.

According to the fourth aspect of the invention, when the temperature of the internal combustion engine is low when the internal combustion engine is warmed up and the viscosity of the oil is high, the inflow pipe is heated and the inner peripheral surface of the inflow pipe is heated. The fluidity of the oil adhering to is increased, and the oil easily flows down the inflow pipe. As a result, in addition to the effect of the invention described in claim 3, the following effect is exhibited. That is, when the inflow pipe is heated by the cooling water, the fluidity of the oil adhering to the inner peripheral surface and the outer peripheral surface of the inflow pipe decreases even when the viscosity of the oil increases, such as when the internal combustion engine warms up. Since it is possible to maintain the fluidity of the adhered oil in a relatively large state by suppressing the occurrence of oil, the oil easily falls from the tip of the inlet portion into the passage, and the oil remaining at the tip of the inlet portion decreases. ,
The intake to the PCV valve is suppressed, and the amount of oil flowing back to the intake passage is reduced.

According to a fifth aspect of the present invention, in the blow-by gas returning apparatus according to any one of the first to fourth aspects, the passage and the breather located upstream of the passage with respect to the flow of the blow-by gas. The chamber is a chamber in which an inlet portion communicates with an inner wall surface of the breather chamber through a communication pipe protruding into the breather chamber.

According to the fifth aspect of the invention, since the inlet portion of the communication pipe projects from the inner wall surface of the breather chamber and is separated from the inner wall surface, the oil adhering to the inner wall surface of the breather chamber is The intake pressure acting through the PCV valve suppresses the inflow into the passage through the inner wall surface. As a result, the following effects are exhibited in addition to the effects of the invention described in the cited claims. That is, since the inlet of the communication pipe projects from the inner wall surface of the breather chamber, the oil adhering to the inner wall surface of the breather chamber is suppressed from flowing along the wall surface into the passage via the communication pipe. As a result, the amount of oil that adheres to the passage wall surface of the passage including the exposed portion is reduced, and as a result, the amount of oil that is sucked into the PCV valve and recirculated to the intake passage is reduced.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. 1 to 3 show a first embodiment, which is a front view of an internal combustion engine E to which a blow-by gas returning apparatus of the present invention is applied. Referring to FIG. 1, the internal combustion engine E is mounted on a vehicle. Is an in-line 4-cylinder in-line 4-cylinder water-cooled 4-cycle internal combustion engine in which a cylinder head 2 is further provided at the upper end of a cylinder block 1 which rotatably supports a crankshaft (not shown) oriented in the left-right direction. The head cover 3 is connected to the upper end of the head 2, the lower block 4 is connected to the lower end of the cylinder block 1, and the oil pan 5 is connected to the lower end of the lower block 4. The crank chamber 6 (see FIG. 2) is formed by the lower portion of the cylinder block 1, the lower block 4, and the oil pan 5.
The cylinder head 2 and the head cover 3 form a valve operating chamber. The cylinder block 1 is provided with four cylinders (the first cylinder 7 of which is shown in FIG. 2) having a central axis extending slightly rearward from the crankshaft side. (Fig. 2
, A bore 7a of the first cylinder 7 of which is shown), and a piston (not shown) is slidably fitted in the bore.
The reciprocating motion of the piston is converted into the rotary motion of the crankshaft via the connecting rod.

In this embodiment, "front and rear, right and left"
Unless otherwise specified, means “front, rear, left and right” when the vehicle is used as a reference.

On the front surface, which is one side surface of the cylinder block 1, there are four intake pipes 10 ₁ to 10 constituting the intake manifold 10.
₄ are arranged in parallel, and the downstream ends of the intake pipes 10 ₁ to 10 ₄ communicate with the four intake ports of the cylinder head 2, while the upstream ends thereof are connected to the surge tank 11 and the surge tank 11
Throttle body 12 with a throttle valve at the upstream end of
Are connected. On the right side of the intake manifold 10, a bracket 20 for an auxiliary machine that is fastened to the cylinder block 1 by a plurality of bolts B is arranged. The bracket 20 is for an auxiliary machine, in this embodiment, a hydraulic power steering system. A hydraulic pump 13, an AC generator 14, an air-conditioning compressor 15, and a water pump (not shown) that generate the hydraulic pressure of are attached to the auxiliary equipment of the crankshaft which is transmitted via a transmission belt 16. It is driven to rotate by power.

In the internal combustion engine E, the blow-by gas in the crank chamber 6 is sucked into the combustion chamber again and burned.
A blow-by gas reducing device for returning blow-by gas to the intake passage is provided. The blow-by gas reducing device includes a breather chamber 21, an introduction path communicating the crank chamber 6 and the breather chamber 21, a PCV valve 40, and the PCV valve. 40 is configured as a main component with the return path 30 provided on the way. Hereinafter, these components will be described.

First, referring to FIGS. 1 and 2, a breather chamber
Reference numeral 21 denotes a first recess 22 formed in the cylinder block 1,
It is formed by the second recess 23 formed in the bracket 20 which is a component of the internal combustion engine E. The first concave portion 22 is provided on the front surface of the cylinder block 1 in front of the first cylinder 7 located at the right end of the cylinder block 1.
The cylinder block 1 is provided with upper, lower, left, and right protrusions that protrude forward so that a part of the cylinder forms a substantially rectangular frame when viewed from the front.
Side upper wall 1a, lower wall 1b, right wall (not shown) and left wall 1c
As surrounded by these four side walls W1, the first cylinder 7
The cylinder wall forming the cooling water jacket 24 is formed as the bottom wall 1d. In the second recess 23, the front end faces of the four side walls W1 on the cylinder block 1 side are the mating faces P on the rear face of the bracket 20 where the generator 14 is attached.
So that the top, bottom, left, and right protrusions that protrude rearward to form a substantially rectangular frame are attached to the upper wall 20a, the lower wall 20b, and the bracket 20 side.
A right wall (not shown) and a left wall 20d are formed surrounded by these four side walls W2. And this second recess
The bottom wall 20d of 23 is formed by the mounting portion of the generator 14, and at the intersection of the bottom wall 20b and the bottom wall 20d, a thermostat (not shown) opened from a radiator (not shown). An introduction passage 25 is formed for introducing the cooling water passing through the pump chamber of the cooling water pump.
The passage wall 25a of the bulge protrudes into the breather chamber 21.

The breather chamber 21 communicates with the crank chamber 6 through the blow-by gas introduction passage, and the opening 26 of the introduction passage in the breather chamber 21 is located near the bottom wall 1d of the left wall 1c and vertically. It is provided slightly below the center of the direction. Air upstream of the throttle valve is introduced into the valve operating chamber through an air passage, and the air flows into the crank chamber 6 through a passage (not shown) provided in the cylinder block 1. . Then, since the intake negative pressure in the intake passage downstream of the throttle valve acts on the breather chamber 21 via the return passage 30, a flow in which the blow-by gas in the crank chamber 6 flows into the introduction passage is formed.

Further, a recovery hole 27 for recovering the oil in the blow-by gas separated in the breather chamber 21 is formed on the right side wall of the side wall W1 at a position substantially at the bottom of the breather chamber 21. To be done. The recovery hole 27 is formed by covering the right end of the cylinder block 1 with a chain cover 8 and extends between a cam shaft for operating an intake valve and an exhaust valve provided in the cylinder head 2 and the crank shaft. The oil that is separated in the breather chamber 21 is opened in the chain chamber that houses the timing chain
Return from 27 to the oil pan 5 through the chain chamber.

Further, the breather chamber 21 has a PCV valve 40.
Is communicated with the throttle body 12 at a position downstream of the throttle valve via a return path 30 provided with. The return passage 30 is formed mainly with a communication pipe 31, a passage 32 and a hose 33.

The return path 30 will be described below with reference to FIG. The bracket 20 has a passage 32 formed of a circular hole with a bottom that opens to the front surface thereof and extends straight obliquely downward from the front surface, and a portion near the upper wall 20a of the bottom wall 20d that is almost the top of the breather chamber 21. From this, a through hole 34 that opens obliquely upward is formed from the innermost portion of the passage wall surface 32a of the passage 32 to the lower portion of the passage wall surface 32a. At this time,
A stepped portion 34a is formed in the lower portion of the passage wall surface 32a where the through hole 34 opens, when the through hole 34 is formed by drilling. When the communication pipe 31 having the inlet portion 31a and the outlet portion 31b is press-fitted into the through hole 34 from the breather chamber 21 side of the through hole 34 toward the passage 32, the outlet portion 31b is connected to the step portion 34a.
By contacting the lower part of the, the communication pipe 31 is positioned in the press-fitting direction. Therefore, the step portion 34a includes the communication pipe 31.
Since it is a positioning part in the press-fitting direction of
The assemblability to the bracket 20 is improved.

Further, in the communication pipe 31 which is a straight circular pipe having a substantially uniform wall thickness, the inlet portion 31a is more than the outlet portion 31b in a state of being fixed at a position defined with respect to the inclined through hole 34. The passage 32 is inclined downward from the outlet portion 31b toward the inlet portion 31a so as to be located below, and through the communication passage 31c formed by the communication pipe 31, the passage 32 is connected to the flow of blow-by gas. The breather chamber 21 located on the upstream side of the passage 32 is communicated.

Further, the inlet portion 31a into which the blow-by gas in the breather chamber 21 flows into the communication pipe 31 is located at the tip of the communication pipe 31 projecting from the inner wall surface 21a of the breather chamber 21 and inside the breather chamber 21. It is open. This entrance 31a
Has a shape in which the communication pipe 31 is cut in a plane inclined with respect to the central axis thereof, and as the lower portion thereof approaches the lowermost portion, the communicating pipe 31 extends obliquely downward with respect to the upper portion in the central axial direction. And three protrusions 31a1.
The width of a1 in the circumferential direction of the communication pipe 31 becomes smaller as it approaches the tip.

On the other hand, the outlet portion 31b located in the passage 32 and open to the inside of the passage 32 has the lowermost portion thereof on the passage wall surface 32a of the passage 32.
By contacting the stepped portion 34a at substantially the same height as the above, the oil does not protrude into the passage 32 and the oil is restrained from staying between the lower portion of the passage wall surface 32a as much as possible. The upper portion 31b1 extends obliquely upward as compared with the lowermost portion and projects into the passage 32. As a result, the communication pipe 31 has a through hole.
It is easy to confirm that the PCV valve 40 is attached to the bracket 20 when the PCV valve 40 is attached to the bracket 20.

Next, the passage 32 and the PCV valve 40 partially accommodated in the passage 32 will be described. On the passage wall surface 32a of the passage 32, a predetermined length L1 from the opening 32b on the front surface toward the back of the passage 32 is longer than a male screw portion 45 described later.
A threaded female screw portion 35 is formed over the area. The PCV valve 40 is attached to the bracket 20 by screwing the male screw portion 45 of the PCV valve 40 into the female screw portion 35.

As shown in FIG. 3, this PCV valve 40 has a tubular valve body 41 having a tool engaging portion 41a having an outer peripheral surface having a hexagonal cross section in the central portion, and a cylindrical valve body. 42, a control spring 43 composed of a compression coil spring, and an inflow pipe
44 and. The body 41 has the tool engaging portion 41a with the PCV valve 40 attached to the bracket 20.
Is located outside the bracket 20 together with the tool engaging portion 41a, and the outflow passage 41c and the measuring hole 41d connected to the outflow passage 41c.
And a valve body 42 located on the other side of the tool engaging portion 41a and the outflow portion 41b to which the hose 33 is connected to the outer periphery thereof.
And a male screw part having a housing hole 41e for housing the control spring 43 and having a screw thread cut on the outer periphery for a predetermined length L2.
With 45. In addition, the valve body 42 has an outlet portion 44b of the inflow pipe 44.
Between the disc-shaped on-off valve portion 42a that seats at the opening and the outlet of the inflow passage 44c formed by the inflow pipe 44 and the peripheral wall of the measurement hole 41d depending on the degree of entry into the measurement hole 41d. By changing the flow passage area of the annular flow passage to be formed, and having a metering valve portion 42b for controlling the amount of blow-by gas recirculated to the intake passage, the control spring 43 causes the opening / closing valve portion 42a by its spring force. Exit 44b
It is urged to come into contact with.

Further, an inflow pipe made of a straight circular pipe having a substantially uniform wall thickness and having an outer diameter smaller than that of the male screw portion 45.
44 is fixed by caulking the end portion 41f of the valve body 41 against the flange of the outlet portion 44b. Then, the PCV valve 40 is screwed into the bracket 20 with a tool that engages with the tool engaging portion 41a, and the male screw portion 45 is screwed to the female screw portion 35 to a specified position. Inside, protruding from the male screw portion 45 in the central axis direction of the valve body 41, extending obliquely downward along the passage 32 and in the upstream direction with respect to the flow of the blow-by gas, the length thereof is Screw part
Internal thread that is exposed in passage 32 without screwing with 45
The inlet portion 44a of the inflow pipe 44 is set at a position beyond the exposed portion 35a of 35. Furthermore, in this state, an annular gap 51 is formed between the exposed portion 35a and the inflow pipe 44, and the passage wall surface 32a and the inflow pipe 44 which are upstream of the exposed portion 35a with respect to the flow of the blow-by gas. An annular gap 52 is also formed between and. Therefore, the exposed portion 35a
A ring-shaped space 50 including a ring-shaped space 51 and a space 52 is formed between the inflow pipe 44 disposed inside the passage wall surface 32a including the passage and the passage wall surface 32a.

When the PCV valve 40 applies an equal pressure to the inflow passage 44c and the outflow passage 41c, the opening / closing valve portion 42a is seated on the outlet portion 44b by the spring force of the control spring 43 to close the inflow passage 44c. . Then, when the intake negative pressure acting on the valve body 42 via the outflow passage 41c is large, such as when the internal combustion engine E is idle or under a low load, the valve body 42 moves against the spring force of the control spring 43. Then, the opening / closing valve part 42a opens the inflow path 44c, and at the same time, the metering valve part 42b largely enters into the metering hole 41d, so that the flow path area of the annular flow path becomes small and the blow-by gas is introduced into the intake path. When the intake negative pressure acting on the valve element 42 via the outflow passage 41c is small due to a decrease in the recirculation amount of the internal combustion engine E, the valve element 42 resists the spring force of the control spring 43. The opening / closing valve part 42a opens the inflow path 44c, while the metering valve part 42b is less likely to enter the metering hole 41d. Compared with that, the amount of blow-by gas recirculated to the intake passage increases.

Further, referring to FIG. 1, the hose 33 connected to the outflow portion 41b is provided in the throttle body 12 and is connected to a connection pipe 36 communicating with the downstream side of the throttle valve. Then, a part of the hose 33 is provided with a protruding bent portion 33a which is bent at a right angle at four places and has a convex shape or a crank shape, and the blow-by gas also bends and flows by the protruding bent portion 33a. The oil in the blow-by gas adheres to the inner surface of the hose 33 during bending.

Next, the operation and effect of the first embodiment constructed as described above will be explained. The blow-by gas in the crank chamber 6 flows into the breather chamber 21 from the opening 26 through the introduction passage by the flow generated by the air introduced into the crank chamber 6 from the air passage through the valve operating chamber, The oil mixed in the blow-by gas is separated in 21.

The blow-by gas in which the oil is separated in the breather chamber 21 and the amount of mixed oil is reduced is
The communication pipe 31, the passage 32, and the hose 33 are passed through the return passage 30 formed as main components, and are returned to the intake passage at a return amount controlled by the PCV valve 40 based on the intake negative pressure. It is burned in the combustion chamber. The oil in the blow-by gas adheres to the inner wall surface 21a of the breather chamber 21 and the outer peripheral surface 31e of the communication pipe 31 in the breather chamber 21, and also flows through the communication passage 31c, the passage 32, the PCV valve 40, and the hose 33. In doing so, it adheres to the inner peripheral surface 31d of the communication pipe 31, the passage wall surface 32a, the inner peripheral surface 44d and the outer peripheral surface 44e of the inflow pipe 44, and further to the inner surface of the hose 33. In particular, in the passage 32, the adhered oil is likely to stay in the threaded exposed portion 35a even though the passage 32 is inclined downward.

However, according to this first embodiment,
In the passage 32, an annular gap 51 is formed between the inflow pipe 44 forming the inflow passage 44c of the PCV valve 40 of the blow-by gas flowing through the passage 32 and the exposed portion 35a of the female screw portion 35, Further, an annular space 52 is also provided between the inflow pipe 44 extending in the upstream direction beyond the exposed portion 35a and the passage wall surface 32a.
Are formed, the female screw portion 35 and the inlet portion 44a of the inflow pipe 44 are formed.
Is increased, the intake pressure acting through the PCV valve 40 suppresses the oil retained in the exposed portion 35a from being sucked from the inflow pipe 44, and the amount of oil flowing back to the intake passage is reduced. To do.

Further, since the inflow pipe 44 projects from the male screw portion 45 in the upstream direction, the PCV valve 40
When the bracket is attached to the bracket 20, the male screw portion 45 of the PCV valve 40 is inserted into the passage 32 before the male screw portion 45.
Since it functions as a guide member when screwing into the female screw portion 35, the workability of attaching the PCV valve 40 to the bracket 20 is improved.

Further, since the inlet portion 31a of the communication pipe 31 is located at the end of the communication pipe 31 projecting from the inner wall surface 21a of the breather chamber 21 into the breather chamber 21 and is separated from the inner wall surface 21a, The oil adhering to the inner wall surface 21a of the breather chamber 21 is caused by the intake negative pressure acting through the PCV valve 40.
Inflow into the passage 32 through the inner wall surface 21a is suppressed. As a result, the amount of oil adhering to the passage wall surface 32a of the passage 32 including the exposed portion 35a is reduced, and thus the PCV is reduced.
The amount of oil sucked into the valve 40 and returned to the intake passage is reduced.

Further, since the communication pipe 31 is inclined obliquely downward from the outlet portion 31b toward the inlet portion 31a, the communication pipe 3
The oil adhering to the inner peripheral surface 31d and the outer peripheral surface 31e of 1 easily collects in the lower part of the inner peripheral surface 31d and the outer peripheral surface 31e, and the collected oil is a communication pipe 31 extending obliquely downward.
Of the inner peripheral surface 31d and the outer peripheral surface 31e of the
reach the tip of a. Then, in the lower portion of the inlet portion 31a, particularly in the lowermost portion, the protruding portion 31a1 is elongated downward in the central axis direction of the communication pipe 31 and protrudes so that the circumferential width becomes smaller. The oil that reaches the tip easily falls into the breather chamber 21 from the protruding portion 31a1 where the adhesion area with the oil is small, so the oil that has flowed down the inner peripheral surface 31d and the outer peripheral surface 31e is the tip of the inlet portion 31a. In this respect also, the passage wall surface 32 of the passage 32 is reduced.
The amount of oil adhering to a is reduced, which leads to PCV valve 4
The amount of oil sucked to 0 and returned to the intake passage is reduced.

Since a protruding bent portion 33a is provided in a part of the hose 33, the oil in the blow-by gas adheres to the inner surface of the hose 33 when the blow-by gas is bent and flows by the protruding bent portion 33a. , The return of oil to the intake passage is reduced.

Next, second, third and fourth embodiments of the present invention will be described with reference to FIGS. These embodiments differ from the first embodiment only in the PCV valve 40, and basically have the same configuration except the above. Therefore, the description of the same parts will be omitted or simplified, and different points will be mainly described. The same reference numerals are used for the same or corresponding members as those of the first embodiment.

First, a second embodiment will be described with reference to FIG. The inlet portion 60a of the inflow pipe 60, like the inlet portion 31a of the communication pipe 31, has a shape in which the inflow pipe 60 is cut along a plane inclined with respect to its central axis, and the lower portion thereof approaches the lowermost portion. The protrusion 60a1 extends diagonally downward in the central axis direction with respect to the upper portion, and the width of the protrusion 60a1 in the circumferential direction becomes smaller toward the tip.

Further, in the PCV valve 40, when the PCV valve 40 is attached to the bracket 20, the protruding portion 60a1 of the inlet portion 60a extends most to a portion visible from the outside, for example, the tool engaging portion 41a. At a position corresponding to the lowermost portion of the inlet portion 60a which is a portion, a confirmation mark 61 as a positioning means, for example, a concave portion is provided so that the position of the lowermost portion in the vertical direction can be confirmed. Therefore, by mounting the PCV valve 40 so that the position of the confirmation mark 61 is at a predetermined position, the protrusion 60a1 can be reliably positioned below the inlet 60a.

According to the second embodiment, the same actions and effects as those of the first embodiment are exhibited, and the following actions and effects are exhibited. That is, the oil attached to the inner peripheral surface 60d and the outer peripheral surface 60e of the inflow pipe 60 is the inner peripheral surface 60d and the outer peripheral surface 60e.
It is easy to collect in the lower part of 60e, and the collected oil flows down the lower part of the inner peripheral surface 60d and the outer peripheral surface 60e of the inflow pipe 60 extending obliquely downward, reaches the tip of the inlet part 60a, and is projected. Because of this, the area of adhesion with oil is small, so that it easily falls into the passage 32 from the protrusion 60a1, so that the oil that has flowed down the inner peripheral surface 60d and the outer peripheral surface is less likely to stay at the tip of the inlet portion 60a. , The amount of oil sucked into the PCV valve 40 is reduced, and therefore the amount of oil flowing back to the intake passage is reduced. Moreover, since there is only one protrusion 60a1, it is easy to form the protrusion 60a1. The inflow pipe
Oil that has fallen into the passage 32 from the inlet 60a of the
2 and the communication passage 31c flow down and fall into the breather chamber 21, and return from the breather chamber 21 to the oil pan 5 through the recovery hole 27.

Next, a third embodiment will be described with reference to FIGS. In the third embodiment, the inlet portion 62 of the inflow pipe 62 is
In a, a plurality of sawtooth-shaped protrusions 62a1 having pointed edges 62a2, in this embodiment, eight protrusions 62a1 are formed at equal intervals in the circumferential direction, and one of them is located at the lower part of the inlet portion 62a. To do. The width of each protruding portion 62a1 in the circumferential direction becomes smaller as the protruding portion 62a1 approaches the tip. Here, the circumferential distance, the circumferential width of the protruding portion 62a1, and the height of the protruding portion 62a1 are appropriately set so that the oil easily drops.

According to the third embodiment, the same actions and effects as those of the second embodiment are obtained except that the protrusion 62a1 can be easily formed, and the following actions and effects are obtained. It That is, as the number of the protrusions 62a1 increases, the number of protrusions 62a1 does not depend on the rotation position when the PCV valve 40 is attached,
Since any one of the protrusions 62a1 is positioned below the inlet 62a, the PCV valve 40 can be easily attached. Even if the number of the protrusions 62a1 is plural, if the number is small and the position of the protrusions 62a1 depends on the rotation position of the PCV valve 40, the confirmation mark 61 as in the second embodiment.
Need to be provided.

A fourth embodiment will be described with reference to FIGS. In the fourth embodiment, at the inlet 63a of the inflow pipe 63, a plurality of protrusions 63a1 are formed at equal intervals in the circumferential direction and are bulged outward in the radial direction. The larger the diameter, the closer it is formed. Also, each protrusion
Since 63a1 consists of a bulging portion, the circumferential width of the outer peripheral surface of each protruding portion 63a1 becomes smaller, and the protruding portion 63a1 located at the lower portion of the inlet portion 63a has an angle larger than the inclination angle of the inflow pipe 63. And tilts diagonally downward. The circumferential spacing, the circumferential width of the protrusion 63a1, and the inclination angle (degree of expansion) are appropriately set so that the oil easily falls.

According to the fourth embodiment, the oil flowing down the inner peripheral surface 63d and the outer peripheral surface 63e of the inflow pipe 63 and reaching the tip of the inlet portion 63a has a projecting portion having a small width in the circumferential direction. 63
Since it easily falls from a1, the same actions and effects as those of the third embodiment are exhibited, and the following actions and effects are exhibited.
That is, the protrusion 63a1 located at the bottom of the inlet 63a is
Since the slanting angle is larger than the slanting angle of the inflow pipe 63, this large slant makes it easier for the oil reaching the tip of the inlet part 63a to drop, and less oil remains at the tip of the inlet part 63a. Become.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is different from the first embodiment only in the communicating pipe, and basically has the same structure except the above. Therefore, the description of the same parts will be omitted or simplified, and different points will be mainly described. The same reference numerals are used for the same or corresponding members as those of the first embodiment.

The outlet 64b of the communication pipe 64 has a shape cut along a plane orthogonal to the central axis of the communication pipe 64, and is located in the middle of the through hole 34. The passage 32 is connected to the communication pipe 64.
It communicates with the breather chamber 21 through the communication passage 64c and the through hole 34.

According to the fifth embodiment, except for the effect due to the different shape of the outlet portion 64b of the communicating pipe 64, the first embodiment
In addition to the same actions and effects as the embodiment, the following actions and effects are exhibited. That is, since the communication pipe 64 is easily formed, and the communication pipe 64 does not project into the passage 32, it is not necessary to consider the accumulation of oil in the passage 32 by the communication pipe 64, and the communication pipe 64 Assembly becomes easy.

In the following, an example in which a part of the configuration of the above example is modified will be described. Second
In the embodiment, the entrance mark is provided by providing the confirmation mark 61.
The protrusion 60a1 is located at the bottom of the 60a, as shown in FIG.
When the protrusion 60a1 is located at the lowermost portion of the inlet portion 60a, the hose connecting portion of the outflow portion 41b 'is bent so that the hose connection portion is directed upward, as shown by the two-dot chain line in FIG. The positioning means of the PCV valve 40 can also be formed by ′. This eliminates the need for the confirmation mark 61 and facilitates connection of the hose 33 to the outflow portion 41b '.

Further, as the shape of the inlet portions 31a, 64a of the communication pipes 31, 64, the shape of the inlet portions 62a, 63a of the inflow pipes 62, 63 of the third and fourth embodiments can be adopted. , The oil adhering to the inner and outer peripheral surfaces of the communication pipe,
Since the amount of oil flowing down the inner peripheral surface and the outer peripheral surface and staying at the tip of the inlet is reduced, the amount of oil flowing into the passage 32 is reduced, and thus the amount of oil flowing back to the intake passage is reduced.

Although the component of the internal combustion engine E is the bracket 20 in the above-mentioned embodiment, it may be any member constituting the internal combustion engine E such as the cylinder block 1, the cylinder head 2, the head cover 3 and the like.

As shown by the chain double-dashed line in FIG. 3, the bracket 20 is branched from the upstream side of the introduction passage 25, which is the cooling water passage of the internal combustion engine E, just below the inflow pipe 44, to introduce the introduction passage 25.
It is also possible to form a water channel 65 that joins the downstream side of the above so that the inflow pipe 44 is heated by the cooling water flowing through the water channel 65.

As a result, when the internal combustion engine E is warmed up, the inflow pipe 44 is efficiently warmed by the cooling water flowing through the water passage 65. Further, after the internal combustion engine E is warmed up, the cooling water cooled by the radiator flows through the water passage 65, so that the inflow pipe 44 is prevented from being heated to a high temperature.

Therefore, when the temperature of the internal combustion engine E is low when the internal combustion engine E is warming up and the viscosity of the oil is high, the inflow pipe is
44 is heated, and the inner peripheral surface 44d and the outer peripheral surface 44e of the inflow pipe 44 are
The fluidity of the oil adhering to the
It becomes easy to run down. When the inflow pipe 44 is heated by the cooling water, the oil adhered to the inner peripheral surface 44d and the outer peripheral surface 44e of the inflow pipe 44 even when the viscosity of the oil increases, such as when the internal combustion engine E is warmed up. Of the oil adhered to the inflow pipe 44 can be maintained in a relatively large state when the internal combustion engine E is operating.
As a result, the oil attached to the inner peripheral surface 44d and the outer peripheral surface 44e of the inflow pipe 44 easily falls into the passage 32 from the tip of the inlet portion 44a, and the oil remaining at the tip of the inlet portion 44a decreases. The intake to the PCV valve 40 is suppressed, and the amount of oil flowing back to the intake passage is reduced. Further, by forming the water passage 65 so as to follow the shape of the passage wall surface 32a, the effect of heating can be further enhanced.

In each of the above embodiments, the inflow pipes 44, 60, 62, 63
Was extending in the upstream direction beyond the exposed portion 35a,
The inlet portions 44a, 60a, 62a, 63a of the inflow pipes 44, 60, 62, 63 may be located closer to the opening 32b in the central axis direction of the passage 32 than the exposed portion 35a. Compared with the first embodiment, the inlet portions 44a, 60a, 62a, 63a and the exposed portion 35a
Although the degree of suction suppression is slightly reduced due to the shortening of the distance between and, the suction of the oil retained in the exposed portion 35a is suppressed.

[Brief description of drawings]

FIG. 1 is a front view of an internal combustion engine to which a blowby gas returning apparatus of the present invention is applied, showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a cross-sectional view of the main parts of FIG.

FIG. 4 is a cross-sectional view of an essential part corresponding to FIG. 3, showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of an essential part corresponding to FIG. 3, showing a third embodiment of the present invention.

6 is an enlarged view of the inflow pipe of FIG. 5 as viewed from the direction of arrow VI.

FIG. 7 is a cross-sectional view of an essential part corresponding to FIG. 3, showing a fourth embodiment of the present invention.

8 is an enlarged view of the inflow pipe of FIG. 7 as seen in the direction of arrow VIII.

9 is a sectional view showing a fifth embodiment of the present invention and corresponding to FIG.

[Explanation of symbols]

1 ... Cylinder block, 2 ... Cylinder head, 3 ... Head cover, 4 ... Lower block, 5 ... Oil pan, 6 ... Crank chamber, 7 ... Cylinder, 8 ... Chain cover, 10 ... Intake manifold, 11 ... Surge tank, 12 ... Throttle body, 13 ... hydraulic pump, 14 ... generator, 15 ... compressor,
16 ... Transmission belt, 20 ... Bracket, 21 ... Breather chamber, 21
a ... Inner wall surface, 22 ... First concave portion, 23 ... Second concave portion, 24 ... Cooling water jacket, 25 ... Introduction passage, 26 ... Opening portion, 27 ... Recovery hole,
30 ... Return path, 31 ... Communication pipe, 31a ... Inlet part, 31a1 ... Projection part, 31b ... Outlet part, 31d ... Inner peripheral surface, 31e ... Outer peripheral surface, 32 ... Passage, 32a ... Passage wall surface, 33 ... Hose, 34 ... through hole, 35 ... female screw part, 35a ... exposed part, 36 ... connecting pipe, 40 ... PCV valve, 41 ... valve body, 42 ... valve body, 43 ... control spring, 44 ... inflow pipe, 44a ... inlet part, 44b ... outlet part, 44d ... inner peripheral surface, 44e ... outer peripheral surface, 45 ... male screw part, 50, 51, 52 ... void, 60 ... inflow pipe,
60a ... inlet part, 60a1 ... projection part, 60d ... inner peripheral surface, 60e ... outer peripheral surface, 61 ... confirmation mark, 62 ... inflow pipe, 62a ... inlet part, 62a1
... projection part, 63 ... inflow pipe, 63a ... inlet part, 63a1 ... projection part, 6
3d ... inner peripheral surface, 63e ... outer peripheral surface, 64 ... communication pipe, 64b ... exit portion,
65 ... Water channel, E ... Internal combustion engine, B ... Bolt, W1, W2 ... Side wall,
P ... Mating surface, L1, L2 ... Length.

Claims (5)

[Claims] 1. A passage provided in a component of an internal combustion engine, and a PCV valve attached to the component, wherein blow-by gas is returned to an intake passage of the internal combustion engine through the passage and the PCV valve. In the blow-by gas returning device, the PCV valve has a male screw portion that is screwed into a female screw portion formed on a passage wall surface of the passage, and protrudes from the male screw portion to prevent blowby gas from flowing in the passage. And an inflow pipe extending in the upstream direction, the inflow pipe being inwardly of an exposed portion of the female screw portion exposed in the passage in a state where the male screw portion is screwed. And a blow-by gas reducing device, wherein the blow-by gas reducing device is arranged via an annular space formed between the exposed portion and the exposed portion. 2. The inflow pipe extends in the upstream direction beyond the exposed portion, and forms a gap including the annular gap with the wall surface of the passage. The blow-by gas reduction device described. 3. The inflow pipe extends obliquely downward from the male screw portion, and a lower portion of an inlet portion of the inflow pipe is a protrusion extending obliquely downward. Alternatively, the blow-by gas returning apparatus according to claim 2. 4. A water passage communicating with a cooling water passage of the internal combustion engine is formed in the component member immediately below the inflow pipe, and the inflow pipe is heated by the cooling water flowing through the water passage. The blow-by gas reducing apparatus according to claim 3, which is characterized in that. 5. The passage and the breather chamber located upstream of the passage with respect to the flow of the blow-by gas communicate with each other via a communication pipe whose inlet portion projects from an inner wall surface of the breather chamber into the breather chamber. The blow-by gas reduction device according to claim 1, wherein the blow-by gas reduction device is provided.