JPH0893436A - Blow-by gas ventilation system for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] In a blow-by gas ventilation system for an internal combustion engine,
The purpose of the present invention is to reduce the size of the oil separator while obtaining sufficient oil deterioration prevention performance. [Structure] Electromagnetic on-off valve 2 during low / medium speed operation of engine E
9 is opened to open the negative pressure introducing pipe 28, the negative pressure in the intake manifold 1 is introduced into the actuator 27 for operating the valve body through the negative pressure introducing pipe 28, and the valve body 26 closes the opening 25. And by operating the passage portion 24 to the open position,
The blow-by gas released in the crank chamber 3 is directly introduced into the oil separator 20 through the passage portion 24 and discharged to the intake manifold 1, while the electromagnetic opening / closing valve 29 is closed during high-speed operation of the engine E. Negative pressure introduction pipe 28
Closed, the valve body 26 opens the opening 25, and the passage 24
The blow-by gas released in the crank chamber 3 is introduced into the oil separator 20 from the inside of the rocker chamber 7 through the opening 25 and is discharged to the intake manifold 1 by operating to the position close to the intake manifold 1. did.

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 structure of a blow-by gas discharge passage for discharging blow-by gas in a crank chamber to an intake system.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine (hereinafter referred to as an engine), as a device for ventilating blow-by gas released from the crank chamber of a crankcase, there is, for example, one shown in FIG. (N14-
1), NISSAN Pulsar N14 type car, 1990, 8
Monthly Nissan Motor Co., Ltd., page B-77, etc.].

In this engine, the blow-by gas discharged in the crank chamber is led to the intake manifold, and at the same time, fresh air is introduced into the engine body from the intake duct or the air cleaner, that is, the rocker chamber and the crank chamber. The internal blow-by gas concentration is reduced to prevent oil deterioration due to blow-by gas, and is specifically configured as follows.

That is, a blow-by gas discharge passage 4 is provided which connects the intake manifold 1 of the engine E and the crank chamber 3 of the crankcase 2. Since the blow-by gas inside the crank chamber 3 contains mist-like oil, an oil separator 5 for separating this oil is provided in the middle of the blow-by gas discharge passage 4. This oil separator 5 is provided in the rocker chamber 7 of the rocker cover 6.
A blow-by gas control valve (PCV valve) 8 is installed inside the upper part of the oil separator 5 and is provided at the outlet of the oil separator 5.

On the other hand, the intake duct 1 downstream of the air cleaner 9
0 and the inside of the crank chamber 3 are provided with a fresh air introduction passage 11 which communicates with each other through the rocker chamber 7. In such a configuration, during low load operation of the engine E, the blow-by gas released in the crank chamber 3 is discharged from the blow-by gas discharge passage 4 to the oil separator 5 and the PCV valve 8 by the action of the negative pressure in the intake manifold 1. While being introduced into the intake manifold 1 through the intake manifold 1, fresh air is introduced into the crank chamber 3 through the fresh air introduction passage 11 and the rocker chamber 7.

[0006]

By the way, the opening of the blow-by gas discharge passage 4 on the engine E main body side is preferably set in the crank chamber 3 having a high blow-by gas concentration as in the prior art of FIG. Compared with the case where the rocker chamber 7 is set, it is advantageous in preventing oil deterioration.

However, due to the rotation of the crankshaft and the reciprocating movement of the piston, the amount of oil mist generated in the crank chamber 3 is much larger than that in the rocker chamber 7, and the blow-by gas discharge passage 4 on the engine body E side. When the opening is set in the crank chamber 3, a large amount of oil mist flows into the blow-by gas discharge passage 4 from the inside of the crank chamber 3, and the oil separator 5 needs to process a large amount of oil mist.

Therefore, it is necessary to enhance the capacity of the oil separator 5, which necessitates an increase in the size of the oil separator 5 and raises the product cost. In addition, the engine E is increased by increasing the size of the oil separator 5.
The size of the engine will become larger and it will be easier to be restricted by the engine layout. On the other hand, if the opening of the blow-by gas discharge passage 4 on the engine E main body side is set in the rocker chamber 7, the above problems can be solved and the oil separator 5 can be downsized, but it is disadvantageous in preventing oil deterioration. Is.

In view of the above conventional problems, the present invention switches the position of the opening of the blow-by gas passage in the engine body between the crank chamber side and the rocker chamber side in accordance with the engine speed. Thus, it is an object to downsize the oil separator while sufficiently obtaining the oil deterioration preventing performance.

[0010]

Therefore, the invention according to claim 1 is an internal combustion engine having a blow-by gas discharge passage for discharging blow-by gas in the crank chamber to the intake system through an oil separator by negative pressure of the intake system. In the blow-by gas ventilation device, the crank chamber-side opening that opens into the crank chamber and the rocker-chamber-side opening that opens into the rocker chamber that communicates with the crank chamber are provided as openings in the engine body of the blow-by gas discharge passage. And a rotation speed detecting means for detecting the engine rotation speed, and a detection signal output from the rotation speed detecting means. Based on the above, the opening / closing is performed so that the crank chamber side opening is opened during low / medium speed operation of the engine and the rocker chamber side opening is opened during high speed operation. Configured to include a control means for switching control of the stage, the.

According to a second aspect of the present invention, the opening / closing means is
A valve element that closes the other opening when one opening is opened, a diaphragm actuator that operates the valve element, a negative pressure introducing passage that introduces negative pressure of the intake system to the actuator, and the negative pressure. An electromagnetic on-off valve interposed in the introduction passage, and the actuator closes the rocker chamber side opening of the valve body when the negative pressure is introduced by the opening operation of the electromagnetic on-off valve of the actuator. When the non-negative pressure is introduced by closing the electromagnetic on-off valve, the valve body is moved to the position where the crank chamber side opening is closed by the normal diaphragm.

The invention according to claim 3 is provided with a fresh air introduction passage for introducing fresh air from the intake system into the crank chamber from the rocker chamber.

[0013]

In the invention of claim 1, when the rocker chamber side opening is closed and the crank chamber side opening is opened, the blow-by gas released in the crank chamber is directly discharged from the crank chamber side. It is introduced into the oil separator through and is led out to the intake system.

On the other hand, when the crank chamber side opening is closed and the rocker chamber side opening is opened, the blow-by gas released in the crank chamber reaches the rocker chamber, and from the rocker chamber side through the rocker chamber side opening. Is introduced into the oil separator and is led out to the intake system. Low- and medium-speed operation of the engine occupies most of all operating conditions, and is greatly affected by oil deterioration. At this time, by directing the blow-by gas from the crank chamber to the blow-by gas discharge passage, sufficient oil deterioration prevention performance can be obtained.

Further, since the amount of oil mist generated in the crank chamber at this time is relatively small, the capacity of the oil separator may be small even if the blow-by gas is directly introduced into the oil separator from the crank chamber. On the other hand, when the engine is operating at high speed, the amount of oil mist generated in the crank chamber is large, but instead of introducing blow-by gas directly into the oil separator from the crank chamber, it should be introduced into the oil separator from the rocker chamber with less oil mist. Therefore, even in this case, the capacity of the oil separator may be small.

In the invention according to claim 2, when the electromagnetic on-off valve is opened, the negative pressure introducing passage is opened, and the negative pressure in the intake system acts on the diaphragm of the actuator through the negative pressure introducing passage. The valve body is operated to a position where the rocker chamber side opening is closed and the crank chamber side opening is opened.
Also, when the electromagnetic on-off valve is closed, the negative pressure introduction passage is closed, and the negative pressure in the intake system does not act on the diaphragm of the actuator, and the diaphragm causes the valve body to open the rocker chamber side opening and the crank chamber side opening. It is operated to the position to close the part.

In the invention of claim 3, the fresh air from the intake system is introduced into the rocker chamber and also into the crank chamber where the blow-by gas generated in the combustion chamber is full and the blow-by gas concentration is high. Further, the concentration of blow-by gas in the engine body is effectively reduced, and the oil deterioration performance due to blow-by gas is improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 show schematic cross-sectional views of an embodiment of the invention described in claims 1 to 3, and the same elements as those in FIG. 5 are designated by the same reference numerals. In these drawings, a blow-by gas discharge passage 21 is provided for leading the blow-by gas in the crank chamber 3 of the crank case 2 to the intake manifold 1 via the oil separator 20 by the negative pressure in the intake manifold 1. The oil separator 2
0 is built in the upper part inside the rocker cover 6, and a blow-by gas control valve (PCV valve) 8 is provided at the outlet of the oil separator 20.

On the other hand, the intake duct 1 downstream of the air cleaner 9
A fresh air introduction passage 22 for introducing fresh air from 0 into the crank chamber 3 from the rocker chamber 7 is provided. An oil separator 23 is interposed in the fresh air introduction passage 22, and the oil separator 23 is built in the rocker cover 6 in parallel with the oil separator 20.

Here, the blow-by gas discharge passage 21
Passage portion 2 as an opening portion that opens into the crank chamber 3 as an opening portion that opens into the main body of the engine E of FIG.
4 and a rocker chamber side opening 25 that opens into the rocker chamber 7 that communicates with the inside of the crank chamber 3. That is, the passage portion 24 is provided in the engine E main body,
One end communicates with the inside of the crank chamber 3, and the other end communicates with the oil separator 20.

The rocker chamber side opening 25 is opened directly in the oil separator 20 and communicates with the rocker chamber 7. In this case, in the wall portion of the oil separator 20, the opening end of the passage portion 24 and the opening portion 25 are laterally adjacent to each other. Then, while providing an opening / closing means that is switched to selectively open / close the passage portion 24 and the rocker chamber side opening portion 25, a rotation speed detecting means for detecting an engine rotation speed and a detection output from the rotation speed detecting means. Control means for switching and controlling the opening / closing means based on a signal.

To explain this structure in detail, the opening / closing means includes a valve body 26 that opens one of the passage portion 24 and the rocker chamber side opening portion 25 and closes the other, and a diaphragm type that operates the valve body 26. The actuator 27 and a negative pressure introducing pipe 28 for introducing a negative pressure of the intake system into the actuator 27.
And an electromagnetic on-off valve 29 installed in the negative pressure introducing pipe 28
And are included.

As shown in FIG. 3, the valve body 26 has a first
Is formed of a substantially L-shaped plate member including a plate portion 26a and a second plate portion 26b, and a support shaft 26A is fixedly attached to a corner portion of the support shaft 26A. The upper end is rotatably supported at the boundary between the passage portion 24 and the opening 25. Therefore, when the valve body 26 is rotated by the rotation of the support shaft 26A, both plate portions 26a and 26b swing around the support shaft 26A, and the first plate portion 26a opens the opening end of the passage portion 24. When the second plate portion 26b closes the opening 25 (see FIG. 3A), the first plate portion 26a has the passage portion 24.
The second plate portion 26b is closed and the second plate portion 26b is opened to open the opening portion 25 (see FIG. 3B).

One end of a link member 30 is connected to the support shaft 26A, and the other end of the link member 30 is connected to the operating rod 3.
Via the diaphragm 27 of the actuator 27
associated with a. This configuration will be described later in detail. The actuator 27 is an actuator body 27A.
And a diaphragm 27a for partitioning the inside of the actuator body 27A into a pressure chamber X and an atmospheric pressure chamber Y.
And an operating rod 31 connected to the diaphragm 27a
And a spring 27b which elastically attaches the diaphragm 27a to the atmospheric pressure chamber Y side in a constantly deformed state.

The operating rod 31 is rotatably connected to the other end of the link 30 on the valve body 26 side. Further, one end of the negative pressure introducing pipe 28 is connected to the negative pressure introducing port 26c formed in the wall of the actuator body 26A on the pressure chamber X side. The other end of the negative pressure introducing pipe 28 is connected to the intake manifold 1 so as to communicate therewith.

Further, the electromagnetic on-off valve 29 is provided in the middle of the negative pressure introducing pipe 28, and when the negative pressure introducing pipe 28 is opened by the opening operation of the electromagnetic on-off valve 29, the inside of the intake manifold 1 is opened. The negative pressure is applied to the actuator 2 via the negative pressure introducing pipe 28.
7 is introduced into the pressure chamber X, and the negative pressure introduction pipe 28 is closed by the closing operation of the electromagnetic on-off valve 29, the negative pressure introduction into the pressure chamber X by the actuator 27 is stopped.

The above-mentioned actuator 27 and valve body 26 are connected to each other when a negative pressure is introduced into the actuator 27.
The valve body 26 moves to a position to close the rocker chamber side opening 25, and when the non-negative pressure is introduced into the actuator 27, the valve body 26
Are operatively associated with the passage portion 24 in the closed position. On the other hand, the rotation speed signal output from the rotation sensor 33 as the rotation speed detecting means is input to the control unit 32 equipped with the function of the control means by software, and the electromagnetic opening / closing valve 29 is controlled from the control unit 32. A control signal is output to.

Next, the operation of this structure will be described. During low / medium speed operation of the engine E, the control unit 32 opens the electromagnetic opening / closing valve 29 based on the signal from the rotation sensor 33. As a result, the negative pressure introducing pipe 28 is opened, and the negative pressure in the intake manifold 1 is introduced into the pressure chamber X of the actuator 27 via the negative pressure introducing pipe 28. Therefore, as shown in FIG. 3 (A), the diaphragm 27a resists the elastic force of the spring 27b and the pressure chamber X
Side, the operating rod 31 is contracted, and the link 30
Through the valve body 26, the opening 25 is closed, and the passage 24
Is operated to the open position.

As a result, as shown in FIG. 1, the blow-by gas released in the crank chamber 3 is
It is directly introduced into the oil separator 20 from the inside through the passage portion 24, and is led out from here to the intake manifold 1 through the PCV valve 8. In addition, the fresh air from the intake duct 10 is introduced into the rocker chamber 7 via the oil separator 23, and is filled with the blow-by gas generated in the combustion chamber to enter the crank chamber 3 having a high blow-by gas concentration. be introduced.

On the other hand, during high speed operation of the engine E,
The control unit 32 closes the electromagnetic opening / closing valve 29 based on the signal from the rotation sensor 33. As a result, the negative pressure introducing pipe 28 is closed and the negative pressure in the intake manifold 1 is not introduced into the pressure chamber X of the actuator 27. Therefore, the diaphragm 27a is replaced by the spring 27b.
Is deformed toward the atmospheric pressure chamber Y side by the elastic force of the
1 is extended and the valve body 26 is operated via the link 30 to a position where the opening 25 opens and the passage 24 closes.

As a result, as shown in FIG. 2, the blow-by gas released in the crank chamber 3 is discharged into the fresh air introduction passage 2
2 to the rocker chamber 7, and from the inside of the rocker chamber 7 to the opening 2
It is introduced into the oil separator 20 via 5 and is led out to the intake manifold 1 via the PCV valve 8. Also in this case, the fresh air from the intake duct 10 is introduced into the rocker chamber 7 and the crank chamber 3.

Here, the low / medium speed operation of the engine E occupies most of all operating conditions and has a great influence on oil deterioration. At this time, by directing the blow-by gas from the crank chamber 3 to the blow-by gas discharge passage 21, sufficient oil deterioration preventing performance can be obtained.
Further, since the amount of oil mist generated in the crank chamber 3 at this time is relatively small as shown in FIG. 4, even if the blow-by gas is directly introduced into the oil separator 20 from within the crank chamber 3, the oil separator 20 Can have a small ability.

On the other hand, in the high-speed operation of the engine E, the amount of oil mist generated in the crank chamber 3 is large as shown in FIG. 4, but blow-by gas is introduced from the crank chamber 3 directly into the oil separator 20. Instead, the oil separator 20 is introduced into the oil separator 20 from the inside of the rocker chamber 7 with a small amount of oil mist. Therefore, the capacity of the oil separator 20 may be small in this case as well.

After all, the capacity of the oil separator 20 can be significantly reduced as compared with the case where the engine E main body side opening of the blow-by gas discharge passage 21 is set in the crank chamber 3 over the entire rotation range of the engine E. , The oil separator 20 can be downsized, and the product cost can be reduced.
As a result, while contributing to downsizing of the engine E and improving the engine layout property, the opening of the blow-by gas discharge passage 21 on the engine E main body side is located in the crank chamber 3 during low and medium speed operation of the engine which is greatly affected by oil deterioration. By setting it, higher oil deterioration preventing performance can be obtained as compared with the case where the opening of the engine E main body side is set in the rocker chamber 7.

The opening of the blow-by gas discharge passage 21 on the engine E main body side is switched depending on whether the amount of oil mist generated is large or small, and is related to the amount of oil mist generated. The above switching is performed depending on the engine rotation speed. That is, since the oil supply amount changes according to the number of rotations of the oil pump due to the engine rotation and the agitation due to the rotating object, the amount of oil mist generated depends on the engine rotation, and hardly changes according to the engine load. Therefore, the opening of the blow-by gas discharge passage 21 on the engine E main body side is switched at the engine rotation speed.

Further, in the above construction, the electromagnetic opening / closing valve 29
When the negative pressure cannot be introduced into the actuator 27 due to malfunction of the actuator or the actuator 27 due to some failure, and in the normal state where the negative pressure is not introduced into the actuator 27, the diaphragm 27a is closed by the elastic force of the spring 27b. Opening body 25 with opening 25, passage 24
Since the closed state is maintained, the oil is not taken out to the intake system due to a large amount of oil mist flowing into the oil separator 20 from the crank chamber 3, and the characteristic of an air flow meter is taken out by taking out the oil to the intake system. It is possible to avoid sudden troubles such as changes and blockage of the auxiliary air passage.

[0037]

As described above, according to the first aspect of the present invention, when the capacity of the oil separator is set in the crankcase at the opening on the engine body side of the blow-by gas exhaust passage over the entire rotation range of the engine. It is possible to significantly reduce the size of the oil separator, reduce the size of the oil separator, reduce the product cost, contribute to the downsizing of the engine, and improve the engine layout. In low / medium speed operation, the engine body side opening of the blow-by gas discharge passage is set in the crank chamber, which has higher oil deterioration prevention performance than the case where the engine body side opening is set in the rocker chamber. Can be obtained.

According to the second aspect of the present invention, the crank chamber side opening and the rocker chamber side opening can be selectively opened and closed by the opening / closing means driven by using the negative pressure of the intake system. According to the third aspect of the present invention, by introducing fresh air from the intake system into the crank chamber, it is possible to more effectively reduce the concentration of blow-by gas in the engine body and improve the oil deterioration performance due to blow-by gas. .

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the invention described in claims 1 to 3.

FIG. 2 is a similar schematic sectional view.

FIG. 3 is a sectional view showing a configuration of opening / closing means in the embodiment.

FIG. 4 is a characteristic diagram showing a relationship between an engine speed and an oil mist generation amount.

FIG. 5 is a schematic sectional view of a conventional example.

[Explanation of symbols]

 1 intake manifold 3 crank chamber 7 rocker chamber 20 oil separator 21 blowby gas discharge passage 22 fresh air introduction passage 24 passage portion (crank chamber side opening) 25 rocker chamber side opening 27 diaphragm actuator 28 negative pressure introduction pipe 29 electromagnetic type Open / close valve 32 Control unit 33 Rotation sensor

Claims (3)

[Claims] 1. A blow-by gas ventilating apparatus for an internal combustion engine, comprising: a blow-by gas discharge passage for discharging blow-by gas in a crank chamber to an intake system through an oil separator by negative pressure of the intake system; and an engine main body of the blow-by gas discharge passage. A crank chamber side opening that opens into the crank chamber and a rocker chamber side opening that opens into the rocker chamber that communicates with the crank chamber are provided as the openings that open inside, and the two openings are selectively opened. While providing an opening / closing means that can be switched to open / close, based on a rotation speed detection means for detecting an engine rotation speed and a detection signal output from the rotation speed detection means, a crank chamber side opening is provided during low / medium speed operation of the engine And a control means for switching the opening and closing means so as to open the rocker chamber side opening at high speed operation. Blowby gas ventilation system for an internal combustion engine characterized by. 2. The opening / closing means, which opens one opening and closes the other opening, a diaphragm type actuator for operating the valve, and a negative pressure of an intake system introduced into the actuator. A negative pressure introducing passage, and an electromagnetic on-off valve interposed in the negative pressure introducing passage. The actuator includes a valve that is deformed by a diaphragm that deforms when a negative pressure is introduced by the opening operation of the electromagnetic on-off valve. The structure is such that the body is operated to the position where the rocker chamber side opening is closed, and when the non-negative pressure is introduced by the closing operation of the electromagnetic opening / closing valve, the valve body is moved to the position where the crank chamber side opening is closed by the normal diaphragm. A blow-by gas ventilation device for an internal combustion engine according to claim 1. 3. The blow-by gas ventilation device for an internal combustion engine according to claim 1, further comprising a fresh air introduction passage for introducing fresh air from the intake system into the crank chamber from the rocker chamber.