JPH0893434A - Blow-by gas ventilating device of internal combustion engine - Google Patents

Abstract

PURPOSE: To aim at reduction of product cost of a blow-by gas ventilating device regulation of an engine layout in that device, by miniaturing an engine due to its constitution in which additional setting of one part of oil separators is not necessary. CONSTITUTION: Such constitution is provided that, a check valve 14 is interposed in a fresh air introduction passage 11 on crank case side, and blow-by gas including oil mist is not allowed to reversely flow to an air intake duct 1 or an air cleaner 2 via the introduction passage 11, while the blow-by gas including the oil mist makes reverse flow to the intake duct 1 or the air cleaner 2 via a fresh air introduction passage 10 on a locker cover side, and the oil mist is separated from the reverse blow-by gas, by an oil separator 12. Consequently, an engine E is miniaturized, and a blow-by gas ventilating device hardly suffers from regulation of engine layout so as to decrease the cost of products.

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 ventilation device for an internal combustion engine, and more particularly to a technique for improving engine layout property while improving oil deterioration preventing performance.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine (hereinafter referred to as an engine), there is, for example, a device as shown in FIG. 2 for ventilating blow-by gas released from the inside of a crankcase [new model vehicle manual (U13 -1), NISSAN
Bluebird U13 type car, published by Nissan Motor Co., Ltd. September 1991, page B-99, etc.].

In this case, the fresh air is introduced not only from the intake duct 1 or the air cleaner 2 into the rocker cover 3, but also into the crankcase 4 having a high blow-by gas concentration, so that only the rocker cover 3 is renewed. Compared with the one that introduces air, a better oil deterioration preventing performance is obtained, and specifically, it is configured as follows.

That is, a blow-by gas passage 5 communicating with the inside of the crankcase 4 of the engine E is provided, and an oil separator 6 into which the blow-by gas introduced into the blow-by gas passage 5 is introduced is provided in the upper portion of the rocker cover 3. It is built in. The outlet of this oil separator 6 has a passage 7
Is communicated with the intake manifold 8 via. A blow-by gas control valve (PCV valve) 9 is provided at the outlet of the oil separator 6.

On the other hand, a rocker cover side fresh air introduction passage 10 that communicates the rocker cover 3 with the intake duct 1 downstream of the air cleaner 2, and a portion near the communication portion of the fresh air introduction passage 10 with the rocker cover 3 is branched. A crankcase side fresh air introduction passage 11 communicating with the crankcase 4 is provided. In such a configuration, in the normal operating range of the engine E, the blow-by gas released in the crankcase 4 passes through the oil separator 6 and the PCV valve 9 from the blow-by gas passage 5 by the action of the negative pressure in the intake manifold 8. To the passage 7, and is introduced into the intake manifold 8 from the passage 7, while fresh air is introduced into the rocker cover 3 and the crankcase 4 through the two fresh air introduction passages 10 and 11.

[0006]

However, each of the conventional blow-by gas ventilation devices has the following problems. In the high load operating range of the engine E, the blow-by gas increases and the negative pressure in the intake manifold 8 decreases, so that the total amount of blow-by gas is reduced to PC.
Since it cannot be released from the V valve 9, the fresh air introduction passage 1
A situation occurs in which blow-by gas containing oil mist flows backward from 0, 11 to the intake duct 1 or the air cleaner 2.

Therefore, another oil separator 12 built in the upper part of the rocker cover 3 and arranged in parallel with the oil separator 3 and an oil separator 13 interposed in the middle of the crankcase side fresh air introduction passage 11 are added. It is necessary to separate the oil in the blow-by gas that flows backward by these oil separators 12 and 13.

In this case, the blow-by gas in the lower rocker chamber 3A inside the rocker cover 3 is the oil separator 1
2 to the rocker cover side fresh air introduction passage 10, and is introduced into the intake duct 1 from the introduction passage 10. The blow-by gas in the crankcase 4 reaches the crankcase-side fresh air introduction passage 11, passes through the oil passage 13 from the introduction passage 11 to the rocker cover-side fresh air introduction passage 10, and is sucked from the introduction passage 10. The flow is such that it is introduced into the duct 1.

If the oil separators 12 and 13 are additionally provided as described above, the engine E becomes large in size, the engine layout is likely to be restricted, and the product cost becomes high. In view of the conventional problems as described above, the present invention has a configuration that does not require additional setting of some oil separators, aims at downsizing of the engine, and is less likely to be restricted by the engine layout,
The purpose is to reduce the product cost.

[0010]

For this reason, the invention according to claim 1 is provided with a blow-by gas passage for communicating the inside of the crankcase of the internal combustion engine with the intake system, and the blow-by gas in the crankcase is provided by the negative pressure of the intake system. Is introduced to the intake system via the blow-by gas passage, while it is equipped with a plurality of fresh air introduction passages that respectively connect the intake system and a plurality of blow-by gas generation parts in the engine body, and fresh air is introduced to each fresh air introduction passage. In a blow-by gas ventilation device for an internal combustion engine configured to be introduced into each blow-by gas generation unit via a predetermined part of the plurality of fresh air introduction passages, only a flow from the intake system to the blow-by gas generation unit is provided. An allowable check valve was installed, and an oil separator was installed in the other passages.

According to a second aspect of the present invention, the plurality of fresh air introduction passages include a passage that connects the intake system and the rocker cover, and a passage that connects the intake system and the crankcase, and the check valve is interposed. The predetermined passage to be installed is the fresh air introduction passage on the crankcase side.

[0012]

According to the invention described in claim 1, in the normal operating range of the engine, the blow-by gas is led to the intake system by the action of the negative pressure in the intake system, and at the same time, the fresh air from the intake system is
It is introduced into the rocker cover and into the crankcase in which the blow-by gas generated in the combustion chamber is full and the blow-by gas concentration is high.

As a result, good oil deterioration preventing performance can be obtained. On the other hand, in the high load operation range of the engine, the blow-by gas increases and the negative pressure in the intake system decreases,
Since the entire amount of blow-by gas cannot be discharged, when the fresh air introduction passage is provided, a situation occurs in which the blow-by gas containing oil mist flows backward through the passage into the intake system.

According to the present invention, since a check valve is provided in a predetermined part of the plurality of fresh air introduction passages, blow-by gas containing oil mist is introduced into the intake system through the passages. There is no backflow. On the other hand, since no check valve is installed in the other fresh air introduction passage, blow-by gas containing oil mist flows back into the intake system through the passage, and this back-flow blow-by gas separates oil mist in the oil separator. To be done.

By thus installing the check valve in a predetermined part of the fresh air introduction passage, it is not necessary to provide an oil separator in this passage, the engine can be downsized, and the layout of the engine is restricted. It becomes difficult and the product cost can be reduced. By the way, the amount of oil mist generated in the crankcase is much larger than that in the rocker cover due to the rotation of the crank and the reciprocating motion of the piston.

For this reason, when the blow-by gas is made to flow back into the fresh air introduction passage on the crankcase side, the oil separator interposed in this passage must have a large and complicated structure. In this respect, according to the second aspect of the present invention, the blow-by gas is made to flow backward to the fresh air introduction passage on the rocker cover side, so that the oil separator interposed in this passage does not have to be large and complicated. Since the applied oil separator can be simplified, the engine can be more effectively downsized, the engine layout can be improved, and the cost can be reduced.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 shows a schematic sectional view of an embodiment of the invention described in claims 1 and 2, and the same elements as those in FIG. 2 are designated by the same reference numerals. In this figure, a blow-by gas passage 5 is provided, an oil separator 6 is built in the upper part of the rocker cover 3, the oil separator 6 is communicated with an intake manifold 8 via a passage 7, and an outlet of the oil separator 6 is The structure in which the PCV valve 9 is interposed is the same as that of the conventional example shown in FIG.

Further, the fresh air introduction passage 10 on the rocker cover side,
The structure in which the crankcase side fresh air introduction passage 11 and the oil separator 12 are provided is the same as that of the conventional example shown in FIG. The configuration different from the conventional example shown in FIG. 2 eliminates the oil separator interposed in the crankcase side fresh air introduction passage 11, and instead, the flow of fresh air into the crankcase side fresh air introduction passage 11. The non-return valve 14 which allows only the above is installed.

Next, the operation of this structure will be described. In the normal operation range of the engine E, the blow-by gas is a PC by the action of the negative pressure in the intake manifold 8.
Is led to the intake manifold 8 via the V valve 9,
At the same time, fresh air from the intake duct 1 is introduced into the rocker cover 3, and is introduced into the crankcase 4 which is filled with blow-by gas generated in the combustion chamber and has a high blow-by gas concentration.

As a result, good oil deterioration preventing performance can be obtained. On the other hand, in the high load operation range of the engine E, as described in the section of the prior art, the blow-by gas increases and the negative pressure in the intake manifold 8 decreases, so that the entire amount of the blow-by gas can be released from the PCV valve 9. Therefore, when the fresh air introduction passages 10 and 11 are provided, a situation occurs in which blow-by gas containing oil mist flows back to the intake duct 1 or the air cleaner 2 through the passages 10 and 11.

According to the configuration of this embodiment, the check valve 14 is provided in the fresh air introduction passage 11 on the crankcase side.
Blow-by gas containing oil mist does not flow back to the intake duct 1 or the air cleaner 2 through the introduction passage 11. On the other hand, since no check valve is provided in the fresh air introduction passage 10 on the rocker cover side, blow-by gas containing oil mist flows backward through the introduction passage 10 into the intake duct 1 or the air cleaner 2, and this reverse flow blow-by The oil is separated from the oil mist in the oil separator 12.

By installing the check valve 14 in the fresh air introduction passage 11 on the crankcase side, it is not necessary to provide an oil separator in the introduction passage 11 and the engine E can be downsized and the engine layout can be improved. It becomes difficult to be restricted and the product cost can be reduced. Here, the amount of oil mist generated in the crankcase 4 is much larger than that in the rocker cover 3 due to the rotation of the crank and the reciprocating motion of the piston.

For this reason, when the blow-by gas is made to flow back into the fresh air introduction passage 11 on the crankcase side, the oil separator interposed in this passage must have a large and complicated structure. In this respect, in the present embodiment, the blow-by gas is made to flow backward to the fresh air introduction passage 10 on the rocker cover side. Therefore, the oil separator 12 provided in the introduction passage 10 does not have a large and complicated structure. It is good to apply the oil separator 12
Therefore, the engine E can be more effectively downsized, the engine layout can be improved, and the cost can be reduced.

The rocker cover 3 side and the crankcase 4
It is not preferable to provide the check valves in both the fresh air introduction passages 10 and 11 on the side because the pressure inside the crankcase 4 rises.

[0025]

As described above, according to the first aspect of the present invention, while maintaining good oil deterioration prevention performance by introducing fresh air into both the crankcase and the rocker cover,
Engine layout and cost reduction can be achieved by reducing some oil separators.

According to the second aspect of the present invention, since the check valve is provided in the fresh air introduction passage on the crankcase side and the blow-by gas is made to flow backward to the fresh air introduction passage on the rocker cover side, this passage is provided. Since the oil separator to be installed in the engine does not have to have a large and complicated structure and the applied oil separator can be simplified, the engine layout and cost can be more effectively achieved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the invention described in claims 1 and 2.

FIG. 2 is a schematic sectional view of a conventional example.

[Explanation of symbols]

 3 Rocker cover 5 Blow-by gas passage 6 Oil separator 8 Intake manifold 10 Rocker cover side fresh air introduction passage 11 Crankcase side fresh air introduction passage 12 Oil separator 14 Check valve

Claims (2)

[Claims] 1. A blow-by gas passage communicating between the inside of a crank case of an internal combustion engine and an intake system, wherein the blow-by gas in the crank case is led to the intake system via the blow-by gas passage by negative pressure of the intake system. Of the internal combustion engine having a plurality of fresh air introduction passages respectively communicating the system and a plurality of blowby gas generation portions in the engine body, and introducing fresh air into each blowby gas generation portion through each fresh air introduction passage. In the blow-by gas ventilation device, a check valve that allows only a flow from the intake system to the blow-by gas generation unit is provided in a predetermined portion of the plurality of fresh air introduction passages, and the other passages are provided in other passages. A blow-by gas ventilation device for an internal combustion engine, characterized in that an oil separator is interposed. 2. The plurality of fresh air introduction passages include a passage communicating the intake system and the rocker cover, a passage communicating the intake system and the crankcase, and a predetermined passage in which a check valve is provided. The blow-by gas ventilation device for an internal combustion engine according to claim 1, wherein is a fresh air introduction passage on the crankcase side.