JP3378234B2 - Breather device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather device provided with a gas-liquid separation chamber for separating oil from blow-by gas in an internal combustion engine.

[0002]

2. Description of the Related Art A blow-by gas reducing apparatus for reducing blow-by gas leaking from between a piston and a cylinder wall in an internal combustion engine to an intake system and burning the blow-by gas is usually provided with a gas-liquid separation chamber for separating oil in blow-by gas. Blow-by gas from which oil has been removed is returned to the intake system to reduce oil consumption.

Utility Model Registration No. 25328, which is provided with this gas-liquid separation chamber in the cylinder head cover that covers the valve operating system.
6 and 7 show an example of an internal combustion engine 01 described in Japanese Patent Publication No. 90.
Shown in. The valve operating mechanism 05 is covered by a cylinder head cover 03 which is joined to overlap the cylinder head 02.

A bottom plate 06 closes a rectangular lower end opening of a side frame wall 04 that forms an upper space inside the cylinder head cover 03 to form a gas-liquid separation chamber 07. A blow-by gas outlet pipe 08 is provided so as to penetrate through the side frame wall 04, and a blow-by gas inlet port 09 is bored in the bottom plate 06 along a corner apart from the blow-by gas outlet pipe 08.

Then, three bent portions 010 are formed at the peripheral edge of the rectangular bottom plate 06, and are bent partially obliquely downward at the side edge where the blow-by gas outlet pipe 08 is provided. Each bent portion 010 is a side frame wall 04. A gap 011 for returning oil is formed between the lower end surface and the bottom surface.

The blow-by gas in the cylinder head cover 03 flows into the gas-liquid separation chamber 07 from the blow-by gas inflow port 09, and after the oil is separated, the blow-by gas outlet pipe
It is returned to the intake system from 08.

The oil separated from the blow-by gas and accumulated on the upper surface of the bottom plate 06 flows through the bottom plate 06 inclined with the inclination of the internal combustion engine toward the oil return gap 011 of the bent portion 010, and the oil return gap 011. Flows out into the space of the valve mechanism 05 below.

The oil-returning gap 011 is blocked by the oil that is about to flow out, and blow-by gas in the cylinder head cover 03 is prevented from being blown up into the gas-liquid separation chamber 07 from the gap 011.

[0009]

However, when the amount of oil flowing out from the oil return gap 011 is small, the gap 011 may not be blocked by the oil. In such a case, the inside of the cylinder head cover 03 Blow-by gas may blow up into the gas-liquid separation chamber 06 from the gap 011 and the separated oil may be mixed again in the blow-by gas and sent to the intake system.

If the clearance 011 for returning the oil is narrowed, the clearance 011 can be easily filled with the oil, but the viscosity of the oil strongly closes the clearance 010 so that a large amount of oil is not collected on the upper surface of the bottom plate 05. , It may stop flowing out from the gap 010.

It should be noted that the oil flow-down pipe is extended downward from the bottom plate constituting the gas-liquid separation chamber, the lower end portion is formed into a lateral S shape, and the separated oil is collected in the S-shaped downward bent portion, and the oil flow-down pipe is formed. Example of blocking the air conditioner (Japanese Patent Laid-Open No. 10-3042)
However, it requires a special oil flow pipe, has a complicated structure, has a large number of parts, and is troublesome to assemble.

If the oil downflow pipe has a large diameter, a large amount of oil will be collected without flowing out. Conversely, if the oil downflow pipe has a small diameter, the oil will be collected in the oil downflow pipe due to the negative pressure of the intake system. The oil flows back and is easily blown up into the gas-liquid separation chamber.

The present invention has been made in view of the above points,
The purpose of this is a simple structure that can prevent blow-by gas from blowing up into the gas-liquid separation chamber by surely blocking the oil return port without accumulating a large amount of oil separated in the gas-liquid separation chamber. The present invention provides a breather device for an internal combustion engine.

[0014]

In order to achieve the above object, the present invention is directed to a gas-liquid separation chamber in which a bottom plate closes a lower end opening of a peripheral wall which defines an inner upper space of a cylinder head cover together with an upper wall. In the breather device for an internal combustion engine that forms a bottom plate, the bottom plate is inclined when the internal combustion engine is in a normal posture, and the bottom side edge of the inclined bottom plate has an oil on the lowest side edge. Is formed so as to straddle the peripheral wall from the lower side to form an oil return port, and the oil held in the recess is in contact with the lower end of the peripheral wall, and the oil returned port is held by the oil. Is used as a breather device for an internal combustion engine.

According to the first aspect of the present invention, since the concave portion is formed in the lowest portion at the side edge which is the lower side of the inclined bottom plate, the oil is constantly accumulated in the concave portion and the concave portion lowers the peripheral wall. Since it is formed so as to straddle from the side and serves as an oil return port, the oil accumulated in the recess overflows and is returned to the inside of the cylinder head cover from the oil return port, and the blow-by gas from which the oil content has been removed is returned to the intake system. It

Since the lower end of the peripheral wall is brought into contact with the oil held in the recess to hermetically close the gas-liquid separation chamber, the blow-by gas in the cylinder head cover enters the gas-liquid separation chamber 06 together with the oil from the oil return port. It can be prevented from being blown up, the gas-liquid separation effect can be maintained high, and the oil consumption can be suppressed.

According to the second aspect of the present invention, the peripheral wall portion of the bottom plate facing the recess is extended downward, and the extension is penetrated into the oil held in the recess, whereby the oil return port is further extended. It can be surely closed airtightly, and it is possible to reliably prevent blow-by gas from being blown up into the gas-liquid separation chamber 06 from the oil return port. The same effect can be obtained without requiring a separate part such as an oil flow pipe.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment according to the present invention will be described below with reference to FIGS. FIG. 1 shows an overall side view of an internal combustion engine 1 to which the breather device according to the present embodiment is applied.

The internal combustion engine 1 is a water-cooled 4-cycle in-line 4-cylinder internal combustion engine, and is mounted horizontally on a vehicle with the crankshaft 7 oriented in the left-right direction. In the following description, front, rear, left and right in the present specification will be referred to as "forward" with the traveling direction of the vehicle as "front", the rear side as "rear", the left hand side as "left" and the right hand side as "right".

The crankcase 2 has a cylinder block 3,
The cylinder head 4 and the cylinder head cover 5 are sequentially stacked and integrally fastened, and an oil pan 6 is joined to the lower surface of the crankcase 2. When the internal combustion engine 1 is in the normal posture, that is, when the vehicle body is not leaning, the cylinder leans diagonally rearward and leans backward.

Auxiliary machinery, that is, a hydraulic pump 11, an AC generator 12, a compressor 13, and a water pump 14 are mounted on the right front side of the internal combustion engine 1 via an auxiliary machinery bracket 10, and a drive pulley fitted to the crankshaft 7 is mounted. 7a, idler pulley 15, driven pulley 11a of hydraulic pump 11, AC
An endless belt 16 is stretched between the driven pulley 12a of the generator 12, the driven pulley 14a of the water pump 14, and the driven pulley 13a of the compressor 13 and driven simultaneously. In addition, four intake pipes (not shown) of each cylinder are arranged side by side from the front surface of the cylinder head 4 on the left side of the above-mentioned accessories.

The cylinder head cover 5 which is superposed on the cylinder head 4 has a box-like shape in which a lower wall is opened by an upper wall 21 and an outer peripheral wall 22. The outer peripheral wall 22 has a long front outer wall 22a and a rear outer wall which face each other. The wall 22b, the short left outer wall 22c and the right outer wall 22d form a substantially rectangular peripheral wall.

FIG. 4 shows a view of the cylinder head cover 5 as seen from the side of the mating surface with the cylinder head 4. Outer wall 22
A groove 23 into which the sealing material 7 (see FIG. 2) is fitted is formed on the lower end mating surface of the substantially rectangular shape.

On the upper wall 21, four fitting cylinders 24 for fitting the spark plug holder 8 (see FIG. 2) are formed side by side in the left-right direction for each cylinder. A substantially rectangular inner peripheral wall 25 is formed so as to substantially surround the upper wall 21 so as to project downward.

The inner peripheral wall 25 is a long front inner wall 25a facing each other.
The rear inner wall 25b, the short left inner wall 25c and the right inner wall 25d form a substantially rectangular shape slightly smaller than the outer peripheral wall 22, and the upper wall
The protruding length from 21 is also shorter than the outer peripheral wall 22, and the lower end surface 26 of the inner peripheral wall 25 that is on the same plane is inside the outer peripheral wall 22 and defines the upper inner space of the cylinder head cover 5 together with the upper wall 21. ing.

The four fitting cylinders 24 also extend downward, and a step portion 27 flush with the lower end surface 26 of the inner peripheral wall 25 is formed in the middle thereof. A portion on the same plane as the lower end surface 26 of the inner peripheral wall 25 is shown by a dot pattern in FIG.

The plane of the lower end surface 26 of the inner peripheral wall 25 is parallel to the lower end surface of the outer peripheral wall 22, and is inclined rearward and downward in accordance with the inclination of the cylinder of the internal combustion engine, and the rear inner side wall 25a
25b is lower.

Referring to FIGS. 2 and 4, the lower rear inner wall 25b gradually approaches the rear outer wall 22b from the left side to the right side (that is, gradually lowers). It has an inclination θ, and its right end portion forms a bulging wall 25e which bulges further outward. Therefore, in the inner peripheral wall 25, the right end portion at a lower position on the lower rear inner side wall 25b, which is further swollen and becomes lower
25e is in the lowest position.

Blow-by gas inlets 30 and 31 are formed in the front inner side wall 25a facing the bulging wall 25e and in the vicinity of the front inner side wall 25a. A guide wall 32 extending leftward from the right inner side wall 25d is formed in the inner peripheral wall 25 substantially parallel to the bulging wall 25e. The guide wall 32 extends rightward from the second fitting tube 24 from the right. 33 extends, and a blocking wall 34 is provided between the second and third fitting cylinders 24, 24 from the right.

A blow-by gas outflow pipe 35 is formed so as to penetrate the left outer wall 22c of the outer peripheral wall 22 from the front portion of the left inner wall 25c of the inner peripheral wall 25 and project outward. In this way, in the inner peripheral wall 25, the blow-by gas flowing from the blow-by gas inlets 30 and 31 by the guide walls 32 and 33 and the blocking wall 34 flows so as to evenly spread to every corner, and flows out from the blow-by gas outflow pipe 35. Has become.

A bottom plate 41 is brought into contact with and joined to the lower end surface 26 of the inner peripheral wall 25, and the lower end opening of the inner peripheral wall 25 is closed to close the gas-liquid separation chamber.
Form 40. That is, the gas-liquid separation chamber 40 is formed in the upper inner space of the cylinder head cover 5 by the upper wall 21, the inner peripheral wall 25, and the bottom plate 41 of the cylinder head cover 5.

As shown in FIG. 2, the cylinder head cover 5
A valve mechanism 50 such as a camshaft 51 and a rocker arm 52 is housed in a space below the gas-liquid separation chamber 40 in the internal space. As shown in FIG. 5, the bottom plate 41 is a substantially rectangular flat plate along the lower end surface 26 of the inner peripheral wall 25, and has four circular holes 42 corresponding to the four fitting cylinders 24 of the cylinder head cover 5. (A circular hole at the right end is partially cut off) is formed, and a portion of the valve mechanism 50 corresponding to the cam of the cam shaft 51 forms a mountain portion 43 that bulges upward.

Further, the bottom plate 41 has an extending portion 41e extending corresponding to the bulging wall 25e on the right rear side of the inner peripheral wall 25, and extends downward along a part of the rear side edge of the extending portion 41e. A small volume recessed portion 44 is formed.

FIG. 3 is a top view of the cylinder head cover 5 seen through from above, showing a state in which the bottom plate 41 is brought into contact with and joined to the lower end surface 26 of the inner peripheral wall 25 of the cylinder head cover 5. The cylinder head cover 5 is shown by a virtual line (two-dot chain line).

The surface of the cylinder head cover 5 that abuts on the bottom plate 41 is shown by a dot pattern, and the lower end surface 26 of the inner peripheral wall 25 abuts along the periphery of the bottom plate 41 to close the gas-liquid separation chamber 40.
In the gas-liquid separation chamber 40, two blow-by gas inlets 30 and 31 are opened in the cylinder head cover 5 on the right side of the front inner side wall 25a, and communicated with the outside by a blow-by gas outflow pipe 35 on the left inner side wall 25c. Further, a bulging wall at the right end of the rear inner wall 25b
An oil return port 45 is formed by opening in the cylinder head cover 5 by a recess 44 that is recessed downwardly of the bottom plate 41 at a portion below 25e.

As shown in FIG. 2, the recess 44 of the bottom plate 41 is formed so as to straddle the bulging wall 25e from below, and the oil return port 45 extends below the bulging wall 25e along the recess 44. It opens like a dive. As described above, since the plane of the lower end surface 26 of the inner peripheral wall 25 is inclined rearward and downward according to the inclination of the cylinder of the internal combustion engine, the bottom plate 41 that is in contact with the lower end surface 26 of the inner peripheral wall 25 is also inclined rearward and downward. is doing.

Then, as described above, the rear inner wall 25 on the lower side
Since b is inclined so as to be gradually lowered from the left side to the right side, and the bulging wall 25e at the right end thereof is at the lowest position, the extending portion 41a of the bottom plate 41 that abuts the bulging wall 25e is It is in the lowest position.

Therefore, the oil separated in the gas-liquid separation chamber 40 mainly flows rearward on the bottom plate 41 inclined rearward and is smoothly guided to the lower right direction along the inclined rear inner wall 25b, It is introduced into the extending portion 41a of the bottom plate 41 along the bulging wall 25e. Then, the oil introduced into the extending portion 41a is recessed 44
Enters and accumulates in the recess 44.

When an appropriate amount of oil is accumulated in the recess 44, the lower end of the bulging wall 25e contacts the liquid surface as shown in FIG. Bulge wall 25
When the lower end of e comes into contact with the oil held in the recess 44, the oil return port 45 is hermetically closed by the oil.

When the oil is fully stored in the recess 44 and further flows in, the oil overflows from the recess 44 and is returned from the oil return port 45 to the space below the gas-liquid separation chamber 40 where the valve mechanism 50 is housed. .

Once the oil has accumulated in the recess 44, a substantially constant amount is always maintained, so that the lower end of the bulging wall 25e is always in contact with the oil liquid surface and the oil return port 45 is hermetically closed. Therefore, blow-by gas in the space where the valve operating mechanism 50 is housed is prevented from being blown up into the gas-liquid separation chamber 40 together with the oil from the oil return port 45, and the gas-liquid separation effect of the gas-liquid separation chamber 40 is kept high. The consumption of oil can be suppressed.

Even if the oil flows back from the oil return port 45 and blow-by gas is blown up, the amount of oil accumulated in the small-volume recess 44 is small, so that the oil consumption can be minimized. This is a simple structure in which the recess 44 is formed in a part of the bottom plate 41, and the number of parts is small and the assembling work is easy.

In this embodiment, the lower end surface of the bulging wall 25e is flush with the lower end surface 26 as a part of the inner peripheral wall 25, but the portion of the bulging wall 25e facing the recess 44 is located downward. To further infiltrate the tip of the oil that has accumulated in the recess 44 to close the oil return port 45 in a more airtight manner, and ensure that blow-by gas is blown from the oil return port 45 into the gas-liquid separation chamber 40. It may be prevented.

On the other hand, the blow-by gas inlet of the front inner wall 25a
The blow-by gas that has flowed into the gas-liquid separation chamber 40 from 30, 31 is, as shown by the broken line arrow in FIG.
Guided by 33, the flow path was lengthened to flow evenly throughout the gas-liquid separation chamber 40, contacting the inner wall surface on the way to adhere the oil component to promote the separation, and the oil component was separated. Blow-by gas flows out from the blow-by gas outflow pipe 35 and is supplied to the intake system.

Referring to FIG. 3, the blow-by gas inlet 30,
Since the guide walls 32 and 33 are arranged at a right angle to the flow where the flow velocity of the blow-by gas flowing from 31 into the gas-liquid separation chamber 40 is aggregated and the flow velocity is the highest, the oil in the blow-by gas is The droplets easily adhere to the wall surface, and the oil separation is further promoted.

The guide wall 32 includes a recess 44 and an oil return port.
Since 45 is cut off from the flow of blow-by gas, the recess
It is possible to prevent the oil accumulated in 44 from being drawn in by the flow of blow-by gas and flowing backward.

[Brief description of drawings]

FIG. 1 is an overall side view of an internal combustion engine to which a breather device according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view of the same main part (a sectional view taken along line II-II in FIG. 3).

FIG. 3 is a top view of a bottom plate with a cylinder head cover seen through from above.

FIG. 4 is a bottom view seen from the mating surface side of the cylinder head cover.

FIG. 5 is a top view of a bottom plate.

FIG. 6 is a cross-sectional view of a conventional cylinder head cover portion.

7 is a cross-sectional view taken along line VII-VII in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank case, 3 ... Cylinder block, 4 ... Cylinder head, 5 ... Cylinder head cover, 6 ... Oil pan, 7 ... Seal material, 8 ... Spark plug holder, 10 ... Auxiliary machine bracket, 11 ... Hydraulic pressure Pump, 12 ... A
C generator, 13 ... Compressor, 14 ... Water pump, 15 ... Idler pulley, 16 ... Endless belt, 21 ... Upper wall, 22 ... Outer peripheral wall, 23 ... Groove, 24 ... Fitting cylinder, 25 ... Inner peripheral wall,
26 ... Lower end surface, 27 ... Stepped portion, 30, 31 ... Blow-by gas inlet, 32, 33 ... Guide wall, 34 ... Blocking wall, 35 ... Blow-by gas outflow pipe, 40 ... Gas-liquid separation chamber, 41 ... Bottom plate, 42 … Circular hole, 43… Mountain part, 44… Recessed part, 45… Oil return port, 50… Valve mechanism, 51…
Camshaft, 52 ... Rocker arm.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruo Watanabe 1-4-1, Chuo, Wako-shi, Saitama Honda R & D Co., Ltd. (58) Fields investigated (Int.Cl. ⁷ , DB name) F01M 13 / 04 F01M 13/00

Claims (2)

(57) [Claims] 1. A breather device for an internal combustion engine in which a bottom plate closes a lower end opening of a peripheral wall defining an inner upper space of a cylinder head cover together with an upper wall to form a gas-liquid separation chamber, the internal combustion engine being in a regular posture. Sometimes the bottom plate is inclined, and a concave portion that holds oil is formed at the lowest portion of the lower side edge of the peripheral portion of the inclined bottom plate so as to straddle the peripheral wall from the lower side. A breather device for an internal combustion engine, characterized in that the oil held in the recess is brought into contact with the lower end of the peripheral wall and the oil held in the recess closes the oil return port in an airtight manner. 2. The breather for an internal combustion engine according to claim 1, wherein the peripheral wall portion facing the concave portion of the bottom plate is extended downward and the extended portion is immersed in the oil held in the concave portion. apparatus.