JPS6213720A - Blow-by gas reflux device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve an oil removing effect as well as to reduce a rate of oil consumption, by connecting an inlet of the oil collection chamber installed in a higher position than an upper part of a cylinder head, to this cylinder head upper part, and connecting the outlet to the upstream side of an air cleaner. CONSTITUTION:Blow-by gas in a crankcase 12a is led into an air cleaner 6 in a suction system by way of an empty space 20 having a valve mechanism on top of a cylinder head 11, making it flow back to a combustion chamber 16. An oil collection chamber 8, having a labyrinthine structure, is installed in a higher position then the top of the cylinder head 11. An inlet of this oil collection chamber 8 is connected to the top of the cylinder head 11, while the outlet is connected to the upstream side of the air cleaner 6. Thus, an oil removing effect is improved and, what is more, a rate of oil consumption is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a blow-by gas reducing device for an internal combustion engine that returns blow-by gas to an intake system and returns it to a combustion chamber.

[Prior art]

The blow-by gas that leaks into the crank chamber from the gap between the piston rings contains a large amount of unburned hydrocarbons (HC), so instead of releasing it directly into the atmosphere, it is returned to the intake system and burned again in the combustion chamber. is legally required. However, as mentioned above, the oil in the crank chamber is mixed into the blow-by gas that leaks into the crank chamber in the form of a mist, so if this oil is returned to the combustion chamber with this oil mixed in, carbon accumulation in the combustion chamber and problems in intake and exhaust gas may occur. This will cause the valve to become stuck. Additionally, since oil is consumed through combustion, it also causes an increase in oil consumption.

Generally, conventional blow-by gas reducing devices guide the blow-by gas in the crank chamber to the upper part of the cylinder head, use some of the mist oil to lubricate the valve mechanism, and then guide it to the intake system. However, a considerable amount of oil still remains in the blow-by gas, and the reduction in carbon accumulation and oil consumption has not always been satisfactory. In particular, the oil removal effect as mentioned above is high in engines of small portable power generators that are housed in a narrow case together with equipment such as an air purifier and a carburetor. , and it was difficult to arrange an oil removal mechanism that could reduce oil consumption in a compact manner.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a blow-by gas reducing device for an internal combustion engine that can increase the removal rate of oil in blow-by gas and reduce oil consumption.

[Structure of the invention]

To achieve the above object, the present invention provides an internal combustion engine in which blow-by gas in the crank chamber is guided to an air purifier in the intake system through a space having a valve mechanism in the upper part of the cylinder head, and is returned to the combustion chamber. An oil collection chamber with a maze structure is provided at a position higher than the top of the cylinder head, and the entrance of this oil collection chamber is connected to the top of the cylinder head.
Further, the air cleaner is characterized in that the outlet is connected to the upstream side of the air cleaner.

〔Example〕

The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 2 shows a portable small-sized power generator with a built-in engine having a blow-by gas reduction device according to the present invention, where 1 is a case that covers the entire power generator, and 2 is a handle for transportation.

3 is an engine provided in the case 1, 4 is a muffler, and a generator 5 driven by the engine 3 is arranged on the back side of the muffler 4. 6 is an air purifier, 7
is a vaporizer. In order to compactly store these in the narrow case 1, the air purifier 6 is placed at the bottom and the vaporizer 6 is placed at the top.

Reference numeral 8 denotes an oil collection chamber that collects oil in the blow-by gas, and is arranged above the air cleaner 5.

FIG. 1 shows details of the engine 3.

10 is the cylinder of engine 3, 11 is the cylinder head,
12 is a crankcase. A piston 13 is fitted into the cylinder 10, and this piston 13 drives a crankshaft 15 via a connecting rod 14. A combustion chamber 16 is formed in the cylinder head 11 corresponding to the upper end of the cylinder 10, and a valve operating mechanism 19 for driving intake and exhaust valves is provided in a space 20 surrounded by a cylinder head cover 11a at the upper part of the cylinder head 11. is provided. There is no oil at the bottom of the crank chamber 12a inside the crankcase 12.
is stored.

A communication hole 18 is provided from the crank chamber 12a through the back of the cylinder 10 to communicate with the space 20 above the cylinder head 11.

This communication hole 18 is connected to the piston 1 during the explosion stroke and intake stroke.
3 descends, the pressurized blow-by gas in the crank chamber 12a is pushed in and forcibly sent to the upper space 20. The blow-by gas sent to this space 20 is adapted to cause oil mixed in a mist form to adhere to the valve mechanism 19 for lubrication.

As shown in FIG. 1, an oil collection chamber 8 is provided above the air cleaner 6, and is located at a higher position than the space 20 above the cylinder head 11 described above.

This oil collection chamber 8 communicates with the space 20 via a pipe 26 connected to the lower part. Oil collection chamber 8
The inside thereof is partitioned by partition plates 27 and 28 to form a flow path having a labyrinth structure.

This labyrinth-structured channel allows the blow-by gas to actively collide with the curved inner wall surface, thereby capturing the oil that has not been removed in the space 20 and causing it to flow down to the lower part of the oil collection chamber 8. . The oil collected at the bottom flows out into the pipe 26 as shown by the broken line arrow when the engine is stopped.
Space due to gravity 20. Crank chamber 12 via oil passage 21
Reflux to a.

The oil collection chamber 8 is connected to the upstream side of the filter 6a of the air purifier 6 via a pipe 29. The blow-by gas from which oil has been removed in the oil collection chamber 8 passes through a filter element 6a in the air cleaner 6, is supplied to the carburetor 7, and then flows back into the combustion chamber 16.

This air cleaner 6 has a lid case 31 on the side to which blow-by gas is supplied from the oil collection chamber 8 . This lid case 31 is detachably attached with screws 32, and the filter element 6a can be replaced by removing this lid case 31.

Further, this air purifier 6 has an oil reservoir 30 formed in its lower part, and the front surface thereof is opened when the lid case 31 is removed. A small amount of oil remaining in the blow-by gas is collected in this oil reservoir chamber 30 before passing through the filter element 6a.

Therefore, almost no oil is allowed to flow to the carburetor 7 side.

According to the blow-by gas reduction device described above, when the piston 13 descends during the explosion stroke or intake stroke, the crank chamber 1
The pressurized blow-by gas in 2a is sent from the passage 18 to the space 20 above the cylinder head 11, and further reaches the oil collection chamber 8 via the pipe 26. A part of the oil in the blow-by gas is used to lubricate the valve mechanism 19 in the space 20, but the oil that is not removed here is further collected by an oil collection chamber 8 disposed outside the engine. Ru. Therefore, most of the oil in the blow-by gas is substantially removed in this oil collection chamber 8.

Since this oil collection chamber 8 is arranged at a higher position than the space 20 above the cylinder fitting 11, when the engine is stopped, it flows down to the space 20 through the pipe 26, and then flows through the oil passage 21 to the crankshaft. It is returned to the room 12a. Therefore, oil is not wasted and the amount of oil consumed can be reduced.

In addition, in the above embodiment, the engine of a portable power generator has a special structure in which the air purifier 6 is placed below the carburetor 7 in order to be compactly stored in the narrow case 1. However, even in such a case, by arranging the oil collection chamber 8 above the air cleaner 6 as described above, it is possible to remove oil from the blow-by gas and remove the oil from the blow-by gas without impeding the above-mentioned compactness. It is possible to reduce oil consumption.

〔Effect of the invention〕

As described above, the present invention provides an internal combustion engine in which blow-by gas in the crank chamber is guided through a space in the upper part of the cylinder head having a valve mechanism, to an air purifier in the intake system, and then returned to the combustion chamber. An oil collection chamber having a labyrinth structure is provided at a higher position than the upper part, and the inlet of this oil collection chamber is connected to the upper part of the cylinder head, and the outlet is connected to the upstream side of the air cleaner, so that the cylinder The oil that could not be removed in the space above the head can be removed in the oil collection chamber outside the engine, and when the engine is stopped, the collected oil is returned to the crank chamber through the space above, so the oil It is possible to increase the removal effect and reduce oil consumption.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an engine having a blow-by gas reduction device of the present invention, and FIG. 2 is a partially cutaway elevational view showing a portable small-sized power generator incorporating the same engine. 3...Engine, 6-Air purifier, 7-Carburetor, 8-Oil collection chamber, 10-Cylinder,
12--Crank case, 12a--Crank chamber, 13-Zeston, 16-Combustion chamber, 18-
- Passage, 19- Valve mechanism, 20... Space, 2
7.2L-m-partition plate.

Claims (1)

[Claims] The blow-by gas in the crank chamber is guided to the air purifier in the intake system through the space above the cylinder head where the valve mechanism is located.
In an internal combustion engine in which the oil is returned to the combustion chamber, an oil collection chamber having a labyrinth structure is provided at a position higher than the upper part of the cylinder head, the inlet of this oil collection chamber is connected to the upper part of the cylinder head, and the outlet is connected to the upper part of the cylinder head. A blow-by gas reduction device for an internal combustion engine, characterized in that it is connected to the upstream side of a purifier.