JPS6257806B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a blow-by gas recirculation device of the type that dilutes blow-by gas with air from an air cleaner and recirculates the diluted blow-by gas to an intake pipe.

[Conventional technology]

Conventionally, blow-by gas is recirculated through a one-way valve (so-called PCV valve) placed between the intake pipe and the blow-by gas generation chamber of the crankcase. In order to prevent the blowby gas passage from being contaminated by the blowby gas, the blowby gas passage is connected to the inside of the air cleaner through a fresh air introduction passage, and the blowby gas is diluted with fresh air and refluxed. Something has also been proposed.

[Problem that the invention seeks to solve]

With the conventional structure, it is not possible to maintain a constant pressure difference between the blow-by gas generation chamber and the air cleaner, so if the amount of blow-by gas generated varies from engine to engine or due to continued use, the air-fuel ratio will fluctuate. be. In other words, when the amount of blow-by gas generated is small, a large amount of fresh air is sucked into the intake pipe, making the air-fuel ratio lean. On the other hand, when the amount of blow-by gas generated increases, the blow-by gas flows back into the air cleaner, making the air-fuel ratio too rich. do. Such a fluctuation in the air-fuel ratio is not desirable because it increases the amount of harmful components generated in the exhaust gas.

Therefore, an object of the present invention is to provide a blowby gas recirculation device of a type that mixes fresh air with blowby gas and recirculates the mixture, and to provide a blowby gas recirculation amount that corresponds to the amount of generated blowby gas without causing a backflow of the blowby gas to the air cleaner. The object of the present invention is to provide a blow-by gas reflux device that can be obtained.

In addition, as a prior application related to the present invention, the patent application filed in 1983-
No. 102444 (see Japanese Unexamined Patent Publication No. 56-27016), the detailed description of the invention of this earlier application shows a type of reflux device that dilutes blow-by gas with fresh air. The present invention is an improvement on the invention of the embodiment of this earlier application.

[Means for solving problems]

According to this invention, the blowby gas generation chamber of an internal combustion engine and the intake pipe are connected by a blowby gas recirculation passage equipped with a flow rate control valve, and the clean space of the air cleaner is connected to the blowby gas generation chamber. In a blow-by gas recirculation system for an internal combustion engine equipped with an air introduction passage, the negative pressure chamber formed by the diaphragm of the flow control valve is connected to the intake pipe by a negative pressure passage, and the negative pressure chamber is connected to the intake pipe by a negative pressure passage. is provided with a pressure regulating valve, the pressure regulating valve is equipped with a diaphragm, and an air chamber on one side thereof is connected to the clean space of the air cleaner via an air introduction passage, and an air introduction port provided in the negative pressure passage. A pressure sensitive chamber is formed on the other side of the diaphragm of the pressure regulating valve, and the pressure sensitive chamber is connected to the blowby gas reflux on the upstream side of the flow rate control valve in the blowby gas reflux direction through a blowby gas pressure passage. It is connected to a constant pressure chamber formed in the passage, and in response to pressure changes in the constant pressure chamber, a valve body installed in the diaphragm of the pressure regulating valve closes the air inlet when the pressure in the constant pressure chamber is high. On the other hand, when the pressure in the constant pressure chamber is low, the air inlet is selectively opened and closed to control the pressure in the negative pressure chamber of the flow control valve, thereby controlling the opening of the flow control valve. Furthermore, the strength of the spring of the pressure regulating valve that biases the air inlet to close is adjusted such that the pressure regulating valve is closed when the pressure in the blow-by gas generation chamber is lower than the internal pressure of the air cleaner. A blow-by gas recirculation device for an internal combustion engine is provided.

[Effect]

When the pressure in the blow-by gas generation chamber increases, the pressure regulating valve closes the air inlet, switches the negative pressure chamber of the flow control valve to negative pressure, and the opening of the flow control valve increases; When the pressure in the blow-by gas generation chamber decreases, the valve element opens the air inlet, the negative pressure chamber of the flow control valve switches to atmospheric pressure, and the opening degree of the flow control valve decreases. That is, the amount of reflux can be obtained in accordance with the amount of blow-by gas generated. In addition, the strength of the spring that biases the pressure regulating valve to close the air inlet is set so that the pressure regulating valve closes and the blowby gas recirculation operation begins when the pressure in the blowby gas generation chamber is lower than the internal pressure of the air cleaner. Therefore, the pressure in the blowby gas generation chamber is prevented from becoming higher than the pressure in the clean space of the air cleaner, and it is possible to prevent or suppress the backflow of blowby gas from the blowby gas generation chamber to the fresh air introduction passage. .

〔Example〕

The present invention will be explained below with reference to the accompanying drawings.
In FIG. 1, an air cleaner 10 and a vaporizer 12 are shown.
is connected, and the air-fuel mixture is introduced into the combustion chamber within the engine body 16 via the intake manifold 14. Exhaust gas is taken out from the exhaust manifold 17.

A blow-by gas generation chamber 18 is formed in the upper part of the engine body 16, and receives blow-by gas generated from the crankcase and cylinder head cover. This blowby gas generation chamber 18 is connected to the intake manifold 14 through a blowby gas recirculation passage 20 to enable blowby gas to be returned to the engine, and is also communicated with the clean space 10a of the air cleaner 10 through a fresh air introduction passage 22. death,
I am starting to receive new energy from here. A flow rate control valve 2 for reflux blow-by gas is provided on the reflux passage 20.
4 is provided.

The flow rate control valve 24 is connected to a diaphragm 26, and its opening degree changes depending on the negative pressure of a negative pressure chamber 28 formed thereon. The negative pressure chamber 28 is connected to the carburetor 12 via a negative pressure passage 30 and receives a negative pressure signal for driving the diaphragm 26. The valve element 32A of the pressure regulating valve 32 for controlling the negative pressure signal introduced from the negative pressure signal passage 30 to the negative pressure chamber 28 is provided in the center of the diaphragm 34, and the pressure sensitive chamber 36 below it is provided. Flow control valve 2 via blow-by gas pressure passage 38
4 is connected to a constant pressure chamber 42 formed by throttles 40A and 40B. (In addition, the aperture is 40
A may also be configured to serve as the valve seat of the valve 24. ) Also, the air chamber 4 above the diaphragm 34
4, when the pressure regulating valve 32 opens against the spring 45, it becomes possible to communicate with the negative pressure signal passage 30 through the air inlet 46, and the negative pressure acting on the diaphragm 26, in other words, the flow rate control valve 24. Control the opening amount. According to the invention, the air chamber 44 is also connected to the clean space 10 of the air cleaner 10 by means of an air introduction passage 48.
a and serves as an air source to the passage 46. Also,
The restrictor 50 serves to substantially prevent the introduced air from flowing back into the vaporizer 12.

To describe the operation of the present invention as described above, both the blow-by gas generation chamber 18 and the clean space 10a of the air cleaner 10 have negative pressure, although it is weak at minus several hundred mmAq. Therefore, the lower pressure sensitive chamber 36 of the diaphragm 34 supporting the pressure regulating valve 32 also has an upper air chamber 44.
Negative pressure also acts on each. Since the spring 45 is disposed in the pressure sensitive chamber 26, the diaphragm 34 receives a suction force due to the negative pressure of the chamber 26 as a downward force.
The sum of the suction force due to the negative pressure in the chamber 44 and the force due to the spring 45 acts as an upward force. The pressure regulating valve 32 closes or opens the air introduction passage 46 depending on whether the upward force or the downward force is large or small.

Now, if the amount of blowby gas in the blowby gas generation chamber 18 increases, the pressure in the constant pressure chamber 42 will increase (the negative pressure will become weaker), so the diaphragm 34
In the balance of the above forces acting on the above, the upward force becomes dominant. As a result, the pressure regulating valve 32 moves in the valve closing direction to separate the air introduction passage 46 from the air chamber 44, and thus flows from the vaporizer 12 to the upper negative pressure chamber 28 of the diaphragm 26 of the flow rate control valve 24 via the negative pressure passage 30. The transmitted negative pressure becomes stronger. As a result, the opening amount of the pressure regulating valve 24 increases and the flow rate of the recirculated blow-by gas from the passage 20 toward the intake manifold becomes large, so that the pressure in the constant pressure chamber 42 returns to its original value. Also,
If, contrary to the above, the amount of blow-by gas generated decreases, the balance of forces acting on the diaphragm 34 will now be predominantly downward, and as a result, the pressure regulating valve 32 will open and the air from the air chamber will be under negative pressure. aisle 30
will be introduced in Thus, the negative pressure in the negative pressure working chamber 28 weakens and the flow rate control valve 24 moves in the closing direction, so that the pressure in the constant pressure chamber 42 returns to the set value.

Upward force applied to the diaphragm 34 of the pressure regulating valve 32 (=pressure of the constant pressure chamber 42 + pressure of the spring 45)>
When the pressure in the air chamber 44 (=air cleaner internal pressure) is satisfied, the pressure regulating valve 32 closes and the flow rate control valve 24 opens. That is, the blowby gas is recirculated in a state where the pressure in the blowby gas generation chamber 18 is lower than the internal pressure of the air cleaner 10. For example, if the internal pressure of the air cleaner is -200mmAq, the load of the spring 45 is 20mmAq.
If the pressure is equivalent to mmAq, the pressure regulating valve 32 is closed when the pressure in the blowby gas chamber 18 is -220 mmAq, while the flow rate control valve 24 is opened, and the blowby gas is recirculated. Therefore, the pressure in the blow-by gas generation chamber 18 is prevented or suppressed from becoming higher than the internal pressure of the air cleaner 10, and blow-by gas is prevented from flowing back to the air cleaner side.

〔Effect of the invention〕

According to this invention, the blow-by gas generation chamber 18
In the blow-by gas recirculation device, which is connected to the air cleaner 10 through the fresh air introduction passage 22, by controlling the flow rate control valve 24 with the pressure regulating valve 32, recirculation can be performed according to the amount of blow-by gas generated. In addition to being able to suppress air-fuel ratio fluctuations, the spring setting of the pressure regulating valve 32 allows the pressure regulating valve 32 to open when the pressure in the blow-by gas generation chamber 18 is lower than the internal pressure of the air cleaner than the internal pressure in the blow-by gas chamber. A reflux operation can be started. Therefore, the pressure in the blow-by gas chamber is prevented from becoming higher than the air cleaner internal pressure, and blow-by gas can be prevented or suppressed from flowing back into the fresh air introduction passage 22. By connecting the air chamber 44 to the inside of the air cleaner, accurate control can be achieved without being affected by internal pressure fluctuations in the air cleaner that change due to aging or individual variation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of the present invention. 10...Air cleaner, 14...Intake manifold, 18...Blowby gas generation chamber, 20...Blowby gas recirculation passage, 24...Flow rate control valve, 2
8... Negative pressure operating chamber, 32... Pressure regulating valve, 44... Air chamber.

Claims (1)

[Claims] 1 The blowby gas generation chamber of the internal combustion engine and the intake pipe are connected by a blowby gas recirculation passage equipped with a flow rate control valve, and a fresh air introduction passage is provided that connects the clean space of the air cleaner to the blowby gas generation chamber. In the blow-by gas recirculation device for an internal combustion engine, the negative pressure chamber formed by the diaphragm of the flow control valve is connected to the intake pipe by a negative pressure passage, and a pressure regulating valve is provided in the middle of the negative pressure passage. The pressure regulating valve is equipped with a diaphragm, and the air chamber on one side thereof is connected to the clean space of the air cleaner through an air introduction passage and communicated with an air introduction port provided in the negative pressure passage. A pressure sensitive chamber is formed on the other side of the diaphragm of the pressure valve, and the pressure sensitive chamber is formed in the blowby gas reflux passage upstream of the flow rate control valve in the blowby gas reflux direction through the blowby gas pressure passage. It is connected to a constant pressure chamber, and in response to pressure changes in the constant pressure chamber,
selectively opening the air inlet so that a valve body installed on a diaphragm of the pressure regulating valve closes the air inlet when the pressure in the constant pressure chamber is high, and opens the air inlet when the pressure in the constant pressure chamber is low; Open and close,
By controlling the pressure in the negative pressure chamber of the flow control valve, the opening degree of the flow control valve is adjusted, and the strength of the spring that biases the air inlet of the pressure regulating valve to close is adjusted. A blowby gas recirculation device for an internal combustion engine, characterized in that the pressure regulating valve is set to close when the pressure in the blowby gas generation chamber is lower than the internal pressure of the air cleaner.