JPS6044493B2 - Blow-by gas treatment equipment for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blow-by gas treatment device for an internal combustion engine,
In particular, by reducing the pressure difference between the negative pressure in the combustion chamber and the crank chamber, it is possible to prevent lubricant oil adhering to the cylinder wall from being sucked into the combustion chamber through the gap between the cylinder and piston and being burned in the combustion chamber. The present invention relates to a blow-by gas treatment device that can prevent blow-by gas.

As shown in FIG. 1, the conventional blow-by gas treatment device transfers the blow-by gas in the crank chamber 2 of the internal combustion engine 1 to the intake passage 8 downstream of the throttle valve 9 and to the air cleaner 14 via the blow-by gas recirculation passage 11. Fresh air is introduced into the crank chamber 2 via the air loss passage 13 and the check valve 13A by a negative pressure wave within the crank chamber 2.

IIA is the main passage of the blow-by gas recirculation path 11 that communicates with the air cleaner 14 via the check valve 11A', and II
B is a branch passage communicating with the intake pipe 8 downstream of the throttle valve 9 via the orifice 11B'. In this way, in the conventional device, the crank chamber 2 is moved by the reciprocating movement of the piston 5.
The check valve 13A of the air-loss passage 13 is opened to introduce fresh air using the pressure pulsations inside the engine, and when the pressure inside the crank chamber 2 is positive, the check valve 13A is closed and the blow-by gas inside the crank chamber 2 is turned into blow-by gas. Since the air is refluxed to the intake passage 8 via the reflux passage 11, the inside of the crank chamber 2 is maintained at substantially atmospheric pressure. Therefore, during engine deceleration, etc., the pressure difference between the negative pressure in the combustion chamber 17 (negative pressure generated during the intake stroke) and the crank chamber 2 becomes large, and the lubricating oil adhering to the wall surface of the cylinder 6 is transferred to the piston 5 and the cylinder wall 6. Since it is sucked into the combustion chamber 17 through the gap and burned, the consumption of lubricating oil increases,
There was a problem that the exhaust composition and catalyst performance deteriorated. The present invention has been made to improve this problem, and in a blow-by gas treatment device for an internal combustion engine that recirculates blow-by gas in the crank chamber to the intake passage, when the negative pressure in the crank chamber reaches a set value or more in the air-loss passage, the passage By installing a pressure control valve that opens the passage and closes the passage when the pressure falls below a set value, the pressure in the crank chamber is controlled to a nearly constant negative pressure, thereby reducing the pressure difference between the combustion chamber and the crank chamber and reducing the pressure that sticks to the cylinder wall. This prevents lubricating oil from being sucked into the combustion chamber and burned and consumed as much as possible.

Next, an example in which the blow-by gas treatment device of the present invention is applied to a supercharged internal combustion engine will be described.

In Fig. 2, 1 is the internal combustion engine body, 2 is the crank chamber, and 3 is the internal combustion engine body.
is a rocker cover, 4 is a communication passage connecting the crank chamber 2 and rocker cover 3, 5 is a piston, 6 is a cylinder, 7
1 is a filter chamber, 8 is an intake passage, 9 is a throttle valve, 10 is an exhaust passage, 11 is a blow-by gas reflux passage that communicates the crank chamber 2 with the intake passage 8 downstream of the throttle valve 9, and 12 is provided in the blow-by gas reflux passage 11. blow-by gas recirculation control valve, 13
is a scavenging passage that communicates the crank chamber 2 with the intake passage 8 upstream of the throttle valve 9 via the rocker cover 3;
One end 13'' opens into a bench lily 8a provided in the intake passage 8. 14 is an air cleaner, 15 is an air flow meter, 16 is a supercharger, and 16a and 16b are supercharger 1.
The intake compressor and exhaust turbine that make up 6.
16c is a shaft connecting the compressor 16a and the turbine 16b, 17 is a combustion chamber, and 18 is a scavenging passage 13.
This is a pressure control valve installed in the

The pressure control valve 18 consists of a control valve body 19 and a valve drive mechanism 20. The control valve body 19 includes a valve seat 19a,
It includes a valve body 19b and a spring 19c, and the spring 19c presses the valve 19b against the valve seat 19a to close the scavenging passage 13. Then, when the engine is started and the pressure in the crank chamber 2 becomes a negative pressure greater than a set value, for example, -10 g or more, the valve body 19b moves against the spring 19c to open the scavenging passage 13. Further, the valve driving device 20 includes a rod 20a whose one end side contacts the valve body 19b via a cushioning material.
and a diaphragm attached to the other end of the rod 20a.
The atmospheric chamber 20c is formed by the diaphragm 20b and the diaphragm 20b.
and a casing 20e that is separated from the pressure chamber 20d, and a diaphragm 20b or rod 20a attached to the casing 20e and springs against the valve body 19b side of the control body 19 at a predetermined pressure. Spring 20f and pressure chamber 20
d and a nipple 20g that communicates with the intake passage 8 downstream of the throttle valve 9. In the engine low load operating range, the diaphragm 20b is moved by the spring 20f by the negative pressure of the intake manifold.
The rod 20a is sucked in the direction of the arrow against the valve/body 19.
Since the negative pressure in the intake passage 8 downstream of the throttle valve 9 decreases in the engine high-load operating range, the rod 20a is slid in the opposite direction of the arrow by the spring 20f, and one end of the rod 20a is The pressure control valve 18 is opened by forcibly pushing the valve body 19b against the spring 19c. FIG. 3 is a sectional view of the blow-by gas recirculation control valve 12, which includes a casing 12a and a casing 1.
Spring 12b and valve body 12c installed in 2a
By screwing one end of the casing 12a into the intake passage 8 and fitting the other end into the blow-by gas return passage 11, the intake passage 8 and the blow-by gas return passage 1 are connected.
The spring 12b is attached between the springs 12b and 12b, and opens the recirculation passage 11 in response to negative pressure in the intake passage.
The valve body 12c is pressed against the stopper 12d attached to one side of the casing 12a against the
Blow-by is performed by closing the opening 12e provided in the gas recirculation path 1.
1 is completely closed. 12f is intake path 8
12g is a threaded portion provided on the outer periphery of one end of the casing 12a to be screwed into the outer periphery of the casing 12a, 12g is a protrusion provided on the outer periphery of the other end of the casing 12a to prevent it from falling off, and 12h is an orifice.

Since the blow-by gas treatment device of the embodiment has the above-mentioned configuration, the valve body 1 of the control valve body 19 is
9b tries to be pressed against the valve seat 19a by the spring 19c, but the force of the spring 20f of the valve driving device 20 is
The valve element 19b opens the scavenging passage 13.

When the engine starts, the negative pressure in the intake passage 8 downstream of the throttle valve 9 acts on the diaphragm 20b of the valve drive device 20, and the spring 20f
The rod 20a moves in the direction of the arrow and separates from the valve body 19b, thereby closing the valve body 19b. Further, the negative pressure in the intake passage 8 downstream of the throttle valve 9 is guided to the crank chamber 2 via the blow-by gas recirculation control valve 12, and when the negative pressure in the intake passage 8 or the crank chamber 2 reaches a set value (-100TwLHg), The negative pressure causes the valve body 19b to slide against the spring 19c to open the scavenging passage 13 and introduce fresh air into the crank chamber 2 via the scavenging passage 13 and the communication passage 4. When the negative pressure in the crank chamber 2 decreases due to the introduction of fresh air, the valve body 1 of the pressure control valve 18
9b is closed by the force of spring 19c. In this manner, during low-load operation of the engine, the negative pressure in the crank chamber 2 is maintained at approximately the set value by opening and closing the pressure control valve 18, and the blow-by gas is passed through the blow-by gas recirculation path 11 and the blow-by gas control valve 12. is returned to the intake passage 8 downstream of the throttle valve 9. Therefore, since the negative pressure in the crank chamber is maintained at a certain constant value, the pressure difference with the negative pressure in the combustion chamber is reduced, and less lubricating oil from the crank chamber is sucked into the combustion chamber.
In addition, during high engine load operation, the intake path 8 downstream of the throttle valve 9
When the pressure becomes negative or positive near atmospheric pressure, the blow-by gas control valve 12 is closed by the pressure in the intake passage 8, while the valve body 19b of the pressure control valve 18 is closed by the force of the spring 20f of the valve drive device 20. is forcibly opened, the blow-by gas is sucked into the scavenging passage 1 by the negative pressure generated in the intake passage 8 at the bench lily 8a portion of the intake passage 8, that is, upstream of the throttle valve 9.
3 to the pressure control valve 19 to the intake passage 8 downstream of the throttle valve 9. Therefore, even if the pressure in the crank chamber becomes abnormally high, the blow-by gas is instead sucked in from the passage 13 through the vent lily 8a of the intake passage 8, thereby preventing its rise.

Note that FIG. 4 shows the control valve body 19 and the valve drive device 20 integrated, and includes a valve body 21a1 a valve seat 21b1 a spring 21c1 a spring seat 21d1 an opening 21e1 an inlet part 21f1 an outlet part 21g.
The pressure in the crank chamber 2 is applied to the valve body 21a through the scavenging passage 13 and the outlet part 21g, and the valve opens when the set negative pressure is exceeded, and fresh air is supplied to the crank chamber 2 through the inlet part 21f1 and the valve body 21a. It is becoming easier to inhale.

Although the embodiment shown in the drawings shows an internal combustion engine with a supercharger, it goes without saying that the present invention can also be used in an internal combustion engine without a supercharger or an internal combustion engine with a carburetor. As explained above, the present invention provides a blowby gas treatment device for an internal combustion engine that recirculates blowby gas in the crank chamber to the intake passage. In addition to providing a reflux control valve, the scavenging passage that communicates the rocker cover that communicates with the crank chamber with the intake passage upstream of the throttle valve opens the passage when the crank chamber reaches a negative pressure that is higher than the set value. This is a blow-by gas processing device equipped with a pressure control valve that closes the passage.The pressure control valve controls the crank chamber to a substantially constant negative pressure, reducing the pressure difference between the crank chamber and the combustion chamber, thereby slowing down the engine. The lubricating oil on the cylinder wall can be prevented as much as possible from entering the combustion chamber through the piston.

As a result, an increase in consumption of lubricating oil can be prevented, and deterioration of exhaust composition and catalyst performance can also be prevented. Also,
By providing a valve drive device that deactivates the negative pressure control valve during high-load engine operation, it is possible to prevent a pressure rise in the crank chamber, simplify the piping that communicates the crank chamber and the intake passage, and improve cost productivity. This has the effect of improving maintenance and inspection.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the conventional example, Fig. 2 is a sectional view of the example of the present invention,
Figure 3 is an enlarged sectional view of the blow-by gas recirculation control valve;
The figure is a sectional view of a pressure control valve and a valve driving device integrated together. 2... Crank chamber, 3... Rocker cover, 8... Intake path, 9... Throttle valve, 11
...Blow-by gas recirculation path, 12...
Blow-by gas recirculation control valve, 13...Scavenging passage, 18...Pressure control valve.

Claims (1)

[Claims] 1. In a blowby gas treatment device for an internal combustion engine that recirculates blowby gas in the crank chamber to the intake passage,
A blowby gas recirculation control valve is provided in the blowby gas recirculation path that communicates the crank chamber and the intake path downstream of the throttle valve, and
The scavenging passage that communicates the rocker cover that communicates with the crank chamber and the intake passage upstream of the throttle valve opens the scavenging passage when the pressure in the crank chamber becomes a negative pressure above a set value, and when the pressure in the crank chamber becomes less than the set value, the scavenging passage opens. A blow-by gas treatment device for an internal combustion engine, characterized by being provided with a pressure control valve that closes a passage.