JPH0631124Y2 - Blow-by gas treatment device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a blow-by gas treatment device for an internal combustion engine such as an automobile. More specifically, the chain traveling part of a rocker cover is partitioned by a partition wall to form a chain chamber in the rocker cover. And a blow-by gas treatment device for an internal combustion engine, which has a valve operating chamber formed therein and an oil separating chamber for blow-by gas is provided on an upper wall portion of the valve operating chamber.

(Prior Art) Generally, a rocker cover of an internal combustion engine covers a valve operating mechanism driven by a cam shaft provided in a cylinder head from above, and such a rocker cover has rigidity, light weight,
Vibration control and sound insulation are required. In particular, in recent years, there is a tendency for the coexistence of the above three parties to be desired, in combination with high performance requirements for vehicles. Further, it is necessary to separate the oil in the blow-by gas generated by the operation of the valve operating mechanism, etc., and recently, there is a case where such a blow-by gas processing mechanism is provided inside the rocker cover.

As a conventional blow-by gas treatment device for this type of internal combustion engine, there is, for example, the one described in the special edition of the internal combustion engine October 1974, "Internal Combustion Engine Structure Drawing", Sankaido, October 1974. . In this blow-by gas processing device, the upper portion of the in-line 6 cylinder is covered with a rocker cover along the valve operating mechanism, and an oil separation chamber for separating oil in the blow-by gas is provided inside the rocker cover. Further, the atmosphere release port for releasing the atmosphere into the rocker cover is opened at a position in the vicinity of the chain chamber where the cam shaft provided on the cylinder head is driven by the chain via the sprocket. The atmosphere (fresh air) passes through the oil separation chamber and returns to the valve operating chamber, so that the valve operating chamber is scavenged. A camshaft provided on the cylinder head is driven by a chain from a crankshaft via a sprocket, and a portion that covers the upper portion of the chain is a so-called chain chamber.

The reason why such chain drive is used is as follows. Recently, high-performance engines tend to be required as the desire for automobiles increases. For this reason, DOHC mechanisms and V-type multi-cylinder engines have come to be installed in general vehicles, and there are some cams that are driven by a chain that can be used in a high rotation range instead of the conventional cogged belt. In such a chain, Since the sprocket is rotated at high speed, its lubrication is especially important.

(Problems to be Solved by the Invention) However, in such a conventional blow-by gas processing apparatus for an internal combustion engine, an atmosphere discharge port for discharging the atmosphere into the rocker cover is opened at a position near the chain chamber. As a result, the atmosphere (fresh air) easily flows into the crank chamber through the chain chamber due to the rotation of the chain, the valve operating chamber cannot be sufficiently scavenged, and the efficiency of blow-by gas treatment is poor. It was

In addition, the splash of lubricating oil due to the running of the chain and the rotation of the cam sprocket fills the vicinity of the atmosphere discharge port, and when the blow-by gas flows backward under high engine load, a large amount of splash oil is sucked into the engine via the atmosphere discharge port. There is also a problem that the oil consumption increases.

(Object of the Invention) Therefore, the present invention aims to increase the scavenging efficiency of the blow-by gas and increase the recovery rate of the oil mist in the blow-by gas to reduce the oil consumption.

(Means for Solving the Problems) In order to achieve the above object, the blow-by gas treatment apparatus for an internal combustion engine according to the present invention has a partition wall that divides a rocker cover that covers the cylinder head of the engine into a chain chamber and a valve operating chamber.
A fuel filler opening along the wall surface of a part of the partition wall and opening to the rocker cover at a position facing the valve operating chamber, and a blow-by gas inlet opening opposite to the wall surface of the partition wall other than a part of the wall surface of the partition wall. A blow-by gas discharge port that communicates the inside and outside of the rocker cover, and an opening area near the blow-by gas flow port formed between the blow-by gas flow port and the blow-by gas flow port from the blow-by gas flow port. It is characterized in that it is provided with an oil separation chamber that gradually increases as it goes away, and an atmosphere discharge port that opens into the valve operating chamber in a direction away from the partition wall.

(Operation) In the present invention, the splashed lubricating oil from the chain chamber is blocked by the partition wall to prevent the lubricating oil from splashing out from the oil supply port, and the consumption of the lubricating oil is prevented.

Further, since the atmosphere discharge port and the blow-by gas inflow port open in opposite directions in the longitudinal direction of the valve operating chamber, they are discharged toward one end side (the side opposite to the partition wall) in the longitudinal direction of the valve operating chamber. The fresh air (atmosphere) makes a U-turn at one end of the valve operating chamber, then runs longitudinally in the longitudinal direction of the valve operating chamber from end to end, and makes a U-turn again at the partition wall located at the other end of the valve operating chamber. Then, it merges with the blow-by gas from the chain chamber or the like and flows into the blow-by gas inlet facing the partition wall. Therefore,
Fresh air (atmosphere) flows into a wide area of the valve operating chamber, and scavenging of the valve operating chamber is reliably performed.

Further, the flow velocity of the blow-by gas of the present application is highest at the inlet of the oil separation chamber and decreases smoothly as it enters the chamber.
This is because the opening area near the entrance gradually increases (gradually increases). Therefore, the behavior of the blow-by gas in the oil separation chamber becomes almost rectified, and the oil mist in the gas is reliably separated (for example, falling due to its own weight), so that the recovery rate of the lubricating oil is increased.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 to 5 are views showing an embodiment of the present invention.

First, the configuration will be described. FIG. 1 is a sectional view of a main part of an in-line four-cylinder engine, showing a state in which a rocker cover is mounted. In this figure, 1 is an engine, 2 is a cylinder head, 3 is a rocker cover, 4 is a cylinder block,
5 is an oil pan and 6 is a chain. The cylinder head 2 is provided with a cam shaft 7, the rotational force of the crankshaft 8 is transmitted to the cam shaft 7 by the chain 6, and the intake and exhaust valves 9 and 10 are driven to open and close by the rotation of the cam shaft 7.
A cam sprocket 7A is provided at the tip of the cam shaft 7, and the cam sprocket 7A is connected via a chain 6 to a sprocket 8A provided at the tip of a crankshaft 8.

The rocker cover 3 is attached to the cylinder head 2 via a gasket 12 so as to cover the valve mechanism 11 such as the cam shaft 7 and the intake and exhaust valves 9 and 10. The rocker cover 3 is provided with a partition wall 13 for partitioning the chain traveling portion, and the partition wall 13 partitions the rocker cover 3 into a chain chamber 3c and a valve operating chamber 3d. At the top of the rocker cover 3, there is an atmosphere communication passage 14
And the blow-by gas discharge passage 15 is connected.

Now, in order to explain the details of the rocker cover 3, we turn to FIG. 2 and subsequent figures. FIG. 2 is a plan view of the rocker cover 3 as seen from the inside, that is, from the lower side, in particular, with the bottom wall of the oil separation chamber removed, and FIG. 3 is a sectional view taken along the line A-A '. , FIG. 4 is a sectional view taken along the line BB '. In these figures, the rocker cover 3 is made of foamed resin, and its surface is coated with a predetermined color. The rocker cover 3 has an upper wall portion 20, longitudinal peripheral walls 21a and 21b, and lateral peripheral walls 22a and 22b.
The thickness of 1a, 21b, 22a, 22b is set to a predetermined width. That is, the upper wall portion 20 is relatively thick, and the other peripheral walls 21a, 21b, 22
The widths a and 22b are set to a relatively thin predetermined width. A gasket groove 23 is formed in the peripheral walls 21a, 21b, 22a, 22b, and a bolt hole 24 for inserting a head bolt is formed.
It has been drilled in several places.

Inside the rocker cover 3, oil separation chambers 25a and 25b for separating the oil in the blow-by gas are formed along the upper wall portion 20. The oil separation chambers 25a and 25b are located below the upper wall portion 20 (engine mounting). It is defined by peripheral walls 26a, 26b central partition wall 27 and bottom wall 28 which extend downwards in time (corresponding to the downward direction in FIG. 1). The bottom wall 28 is attached to the boss portion 2 of the peripheral walls 26a and 26b by tightening a screw 29 as shown in FIG.
It is fixed to 6c (see FIG. 2), and a recess 28a is formed in the bottom wall 28 in some places, and its peripheral edge 28b is bent to increase the rigidity. Inside the oil separation chamber 25a, ribs 30a, 30b having a wall height lower than that of the peripheral walls 26a, 26b and the central partition wall 27 are provided, and these ribs 30a, 30b continuously extend from the upper wall portion 20. ing. Similar ribs 31a, 31b
Is also provided inside the other oil separation chamber 25b, and these ribs 30a, 30b, 31a, 31b bend the flow direction of blow-by gas or the atmosphere to improve the efficiency of oil separation. Further, two oil return holes 28c are formed in the bottom wall 28, and the oil accumulated inside flows out from the oil return holes 28c.

Further, the peripheral walls 21a and 21b of the rocker cover 3 and the oil separation chambers 25a and 2a
A gap H is formed between the peripheral walls 26a and 26b of 5b,
The peripheral walls 26a and 26b are provided separately from the peripheral walls 21a and 21b, unlike the conventional case. Therefore, the peripheral wall 21a of the rocker cover 3,
21b is thinner than before. On the other hand, the partition wall 1 having the same height as the peripheral walls 21a and 21b is provided on one side inside the rocker cover 3.
3 is provided, and the partition wall 13 partitions the chain chamber 3c that covers the upper portion of the chain 6 that drives the cam shaft 7 and the valve operating chamber 3b that covers the valve operating mechanism 11.

Turning to FIG. 3, an opening 32 is formed between the lower end 13a of the partition wall 13 and the upper surface 2A of the cylinder head 2 shown in phantom, and the chain chamber 3c is formed through the opening 32 and the partition wall 13.
And the crankcase 16 communicate with each other to form a blow-by gas passage (see FIG. 1). In addition, as shown in FIG.
An oil filling port 33 for filling the oil is formed above, and a filling cap 34 is screwed into the filling port 33. The position of the oil supply port 33 is formed in a portion where the oil does not directly flow into the chain chamber 3c by the partition wall 13 when the oil is supplied, in other words, since the partition wall 13 is present (there was no prior art), the oil is The structure prevents oil from splashing due to direct inflow into the chain chamber 3c. Further, the upper wall portion 20 of the rocker cover 3 is provided with an atmosphere communication passage 14 and a blow-by gas discharge passage 15, and the inside of the rocker cover 3 is provided with an atmosphere intake port 35 and a blow-by gas discharge port 36 respectively corresponding thereto. (See FIG. 2).

Next, the operation will be described.

The fresh air (atmosphere) for blow-by gas scavenging is supplied from an air cleaner (not shown) to the atmosphere communication passage 14, the atmosphere intake port 35, and the atmosphere emission port.
After entering the oil separation chamber 25b through 35 ', it passes through and flows into the valve operating chamber 3d (inside the rocker cover 3) as indicated by the white arrow. On the other hand, the blow-by gas is blown by the blow-by gas inlet 37, the oil separation chamber from the valve operating chamber 3d side as shown by the black arrow.
25a and the blow-by gas discharge port 36 are sequentially sucked into an intake passage (not shown). By such a flow, the oil in the blow-by gas is separated in the oil separation chamber 25a, the oil stays in the bottom wall 28, and is returned from the oil return hole 28c to the valve operating chamber 3d side. In this case, the blow-by gas inflow port 37 is formed near the chain 6 of the valve operating chamber 3d, and the partition wall 13 for partitioning the chain chamber 3c and the valve operating chamber 3d directly moves a large amount of lubricating oil droplets in the chain chamber 3c. Since it does not flow into the blow-by gas inlet 37 of the valve chamber 3d, the oil separation chamber 25
The miniaturization and simplification of a can be achieved. Also, the valve operating chamber 3d
Since the air release port 35 is opened to one side in the longitudinal direction of the engine 1 (the sump side near the center of the cylinder row, the left side in the first drawing) so as to be separated by the chain chamber 3c and the oil separation chamber 25b, The valve operating chamber 3d can be sufficiently scavenged with fresh air (atmosphere), and the deterioration of the lubricating oil accumulated on the upper surface 2A of the cylinder head 2 can be prevented.

Further, when the engine 1 has a high engine load, a large amount of splash oil is filled in the chain chamber 3c and the valve operating chamber 3d due to the rotation of the chain traveling portion. However, because of the above-mentioned configuration, a large amount of splash oil is released to the atmosphere. It is possible to prevent the situation where it directly flows into the 35 '. Therefore, the air outlet
It is possible to prevent the above-mentioned splash oil from being sucked into the engine through 35 ', and prevent an increase in oil consumption.

Furthermore, since the chain chamber 3c and the valve operating chamber 3d communicate with each other through the opening 32 below the partition wall 13, the chain chamber 3c
Fresh air also flows into the crank chamber 16 connected to the crank chamber 16
The blow-by gas in the inside can be sufficiently scavenged, and the deterioration of the lubricating oil in the oil pan 5 can be prevented.

(Effect) According to the present invention, the splashed lubricating oil from the chain chamber is blocked by the partition wall, and it is possible to prevent the lubricating oil from splashing out from the oil supply port and prevent the consumption of the lubricating oil.

Further, since the atmosphere discharge port and the blow-by gas inflow port open in opposite directions in the longitudinal direction of the valve operating chamber, fresh air (atmosphere) can be poured into a wide range in the valve operating chamber, and the valve operating It is possible to reliably perform scavenging of the room.

Furthermore, the behavior of the blow-by gas inside the oil separation chamber can be made to be in a state almost like rectification, and the oil mist in the gas can be reliably separated (for example, falling by its own weight), resulting in the recovery rate of the lubricating oil. Can be increased.

[Brief description of drawings]

1 to 5 are views showing an embodiment of a rocker cover device for an internal combustion engine according to the present invention. FIG. 1 is a sectional view of an essential part of the engine, and FIG. 2 is a view of the rocker cover from the inside. FIG. 3 is a plan view, FIG. 3 is a sectional view taken along the line AA ′ in FIG. 2, FIG. 4 is a sectional view taken along the line BB ′ in FIG. 2, and FIG. 5 is a bottom view of the rocker cover shown in FIG. It is a top view which shows the state which attached the wall. 1 ... Engine, 2 ... Cylinder head, 3 ... Rocker cover, 3c ... Chain chamber, 3d ... Valve chamber, 4 ... Cylinder block, 6 ... Chain, 7 ... Cam shaft, 7A, 8A ...... Sprocket, 11 ...... Valve mechanism, 13 ...... Differential wall, 35 '...... Air release port, 35 ...... Air intake port.

Claims (1)

[Scope of utility model registration request] 1. A partition wall for partitioning the inside of a rocker cover that covers a cylinder head of an engine into a chain chamber and a valve operating chamber, and an opening in the rocker cover along a part of the wall surface of the partition wall and facing the valve operating chamber. A fuel filler port, a blow-by gas inlet opening to face a partition wall surface other than a part of the partition wall, a blow-by gas discharge port communicating the inside and outside of the rocker cover, the blow-by gas inlet and the blow-by An oil separation chamber that is formed between the blow-by gas inlet and an opening area near the blow-by gas inlet, and gradually increases as it moves away from the blow-by gas inlet, and opens into the valve operating chamber in a direction away from the partition wall. A blow-by gas treatment device for an internal combustion engine, comprising: