JP2024041416A - Blow-by gas recirculation device for internal combustion engines - Google Patents

Abstract

An object of the present invention is to provide a blowby gas recirculation device for an internal combustion engine in which a decrease in detection accuracy of blowby gas pressure is suppressed.
In a blow-by gas recirculation device for an internal combustion engine equipped with a supercharger, a first communication port communicates with a head cover of the internal combustion engine, and a second communication port communicates with an intake passage upstream of a compressor of the supercharger. an oil separator having a communication port and a third communication port; a case defining a sub-chamber communicating with the third communication port; and a pressure sensor for detecting pressure within the sub-chamber; The straight-line distance between the opening and the third communication port is longer than the straight-line distance between the first communication port and the second communication port, and the distance between the first communication port and the third communication port is longer than that between the first communication port and the second communication port. A blow-by gas recirculation device for an internal combustion engine that is longer than the straight line distance between the two.
[Selection diagram] Figure 2

Description

The present invention relates to a blow-by gas recirculation device for an internal combustion engine.

By connecting the atmosphere-side separator and the pressure sensor via the auxiliary chamber, the influence of the blow-by gas flow can be suppressed and the blow-by gas pressure can be detected (see, for example, Patent Document 1).

JP 2021-113521 Publication

However, if the flow rate of the blow-by gas is large relative to the volume of the auxiliary chamber, the flow of the blow-by gas may reduce the accuracy of pressure detection by the pressure sensor.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a blowby gas recirculation device for an internal combustion engine in which a decrease in detection accuracy of blowby gas pressure is suppressed.

The above object is to provide a blow-by gas recirculation system for an internal combustion engine equipped with a supercharger, including a first communication port communicating with a head cover of the internal combustion engine, and a second communication port communicating with an intake passage upstream of a compressor of the supercharger. an oil separator having a communication port and a third communication port; a case defining a sub-chamber communicating with the third communication port; and a pressure sensor for detecting pressure within the sub-chamber; The straight-line distance between the opening and the third communication port is longer than the straight-line distance between the first communication port and the second communication port, and the distance between the first communication port and the third communication port is longer than that between the first communication port and the second communication port. This can be achieved by a blow-by gas recirculation system of the internal combustion engine, which is longer than the straight line distance between the two.

The second communication port is located on one side of the oil separator in the longitudinal direction of the first communication port, and the third communication port is located on the other side of the oil separator in the longitudinal direction of the first communication port. It may be located in

The linear distance between the first communication port and the second communication port may be longer than the linear distance between the first communication port and the third communication port.

The device may include a first communication pipe that communicates the third communication port and the sub-chamber, and a second communication pipe that communicates the case and the pressure sensor.

According to the present invention, it is possible to provide a blowby gas recirculation device for an internal combustion engine in which a decrease in detection accuracy of blowby gas pressure is suppressed.

FIG. 1 is a schematic configuration diagram of an engine. 2A and 2B are schematic configuration diagrams of the atmospheric side separator. 3A and 3B are schematic configuration diagrams showing the flow of blow-by gas within the atmospheric side separator in a supercharging operation state.

[Schematic engine configuration]
FIG. 1 is a schematic configuration diagram of an engine 10. The engine 10 is a spark ignition four-cylinder gasoline engine, which is an example of an internal combustion engine, but the engine 10 is not limited to this, and may be other than four cylinders, for example, a compression ignition diesel engine or other type engine. It may also be an engine.

The engine 10 includes an engine body 11, a head cover 12, a crankcase 13, a piston 14, a combustion chamber 15, an intake passage 16, a supercharger 20, an intercooler 22, and a throttle valve 24. The engine body 11 includes a cylinder 11a, a head cover 12 provided above the cylinder 11a, and a crankcase 13 provided below the cylinder 11a. The piston 14 reciprocates within the combustion chamber 15 of the cylinder 11a. An intake passage 16 is connected to each cylinder of the engine body 11 via an intake manifold 16a.

The air cleaner 17 is attached near the inlet portion of the intake passage 16. The compressor 20a of the supercharger 20 is installed downstream of the air cleaner 17 in the intake passage 16, and compresses intake air. The compressor 20a is integrally connected to a turbine 20b disposed in the exhaust passage via a connecting shaft.

The intercooler 22 is installed downstream of the compressor 20a in the intake passage 16, and cools the supercharged air. An electronically controlled throttle valve 24 is provided downstream of the intercooler 22. An intake manifold 16a is arranged downstream of the throttle valve 24.

A blow-by gas guide passage 31 is provided within the cylinder 11a and the head cover 12. The blow-by gas guide passage 31 is formed to penetrate through the cylinder 11 a and the head cover 12 , communicates the inside of the crankcase 13 with the main separator 43 , and directs the blow-by gas existing inside the crank case 13 to the main separator 43 . lead Further, the main separator 43 is provided with a communication port 431 that communicates the head cover 12 and the main separator 43, and guides the blow-by gas present in the internal space of the head cover 12 to the main separator 43.

The blowby gas is guided to the main separator 43 via the blowby gas guide passage 31, and the blowby gas from which the oil mist has been separated by the main separator 43 is led to the blowby gas recirculation passage 36 that communicates the main separator 43 and the intake manifold 16a. , is returned to the intake manifold 16a.

A PCV (Positive Crankcase Ventilation) valve 38 is installed at the end of the blow-by gas recirculation passage 36 on the main separator 43 side. The PCV valve 38 is configured as a differential pressure operated valve that operates according to the differential pressure between the internal space of the head cover 12 on the upstream side and the intake manifold 16a on the downstream side. Such a PCV valve 38 adjusts the flow rate of the blowby gas flowing back into the intake manifold 16a, and prevents the blowby gas from flowing back into the internal space of the head cover 12.

A fresh air introduction passage 34 is provided that communicates the internal space of the head cover 12 with the intake passage 16 on the upstream side of the compressor 20a and downstream of the air cleaner 17. More specifically, the fresh air introduction passage 34 communicates the intake passage 16 with an atmosphere-side separator 44 included in the blow-by gas recirculation device 4, which will be described later. The atmosphere side separator 44 is provided with a first communication port 441, which communicates the atmosphere side separator 44 with the internal space of the head cover 12. Further, a fresh air guide passage 33 communicates the inside of the head cover 12 and the inside of the crankcase 13. Therefore, fresh air passing through the intake passage 16 is introduced into the internal space of the head cover 12 and the crankcase 13 by the fresh air introduction passage 34, the atmospheric side separator 44, and the fresh air guide passage 33.

When the engine 10 is operated in a naturally aspirated state, the pressure inside the combustion chamber 15 and intake manifold 16a downstream of the throttle valve 24 is negative, and the pressure in the intake passage 16 upstream of the compressor 20a is atmospheric pressure. . Therefore, fresh air flows into the fresh air introduction passage 34, the atmospheric side separator 44, the head cover 12, the fresh air guide passage 33, and the crankcase 13. Further, the blowby gas is returned from the crankcase 13 and the head cover 12 to the intake manifold 16a via the main separator 43 and the blowby gas recirculation passage 36. The main separator 43 separates the oil component from the blow-by gas. In this way, the blow-by gas is supplied from the intake manifold 16a into the combustion chamber 15, and the blow-by gas can be combusted.

When the engine 10 is operated in a supercharged state, the combustion chamber 15 and the intake manifold 16a downstream of the compressor 20a have a positive pressure, and the intake passage 16 upstream of the compressor 20a has a negative pressure. Therefore, the blowby gas flows from the crankcase 13 through the blowby gas guide passage 31, the main separator 43, the head cover 12, the atmosphere side separator 44, and the fresh air introduction passage 34 in this order, and flows back into the intake passage 16 upstream of the compressor 20a. . In the atmosphere side separator 44, oil components are separated from the blow-by gas. In this way, the blow-by gas is supplied into the combustion chamber 15, and the blow-by gas can be combusted.

[Schematic configuration of blow-by gas recirculation device]
The blow-by gas recirculation device 4 includes an atmospheric side separator 44 , a first communication pipe 51 , a second communication pipe 52 , a case 60 , and a pressure sensor 70 . The atmosphere side separator 44 is an example of an oil separator. The atmosphere side separator 44 includes a first communication port 441 , a second communication port 442 , and a third communication port 443 . The first communication port 441 communicates with the inside of the head cover 12. The second communication port 442 communicates with the fresh air introduction passage 34. The third communication port 443 communicates with the pressure sensor 70 via the first communication pipe 51, the case 60, and the second communication pipe 52. Case 60 defines an auxiliary chamber 61 . Although the case 60 is schematically shown in FIG. 1, it is actually fixed to the upper surface of the head cover 12.

The pressure sensor 70 is not directly attached to the atmosphere-side separator 44, but is attached via the auxiliary chamber 61 that is connected to the atmosphere-side separator 44. In detail, the auxiliary chamber 61 of the case 60 is connected to the atmosphere-side separator 44 via the first communication pipe 51, and the pressure sensor 70 is connected to the auxiliary chamber 61 of the case 60 via the second communication pipe 52. Therefore, the pressure sensor 70 is provided in a position that is not easily affected by the flow of blow-by gas in the atmosphere-side separator 44, and a decrease in the detection accuracy of the pressure sensor 70 due to the influence of the blow-by gas flow is suppressed.

[Schematic configuration of atmospheric side separator]
The configuration of the atmosphere side separator 44 will be explained. 2A and 2B are schematic configuration diagrams of the atmosphere side separator 44. FIG. 2A is a schematic diagram of the atmosphere side separator 44 viewed from the side of the engine 10. FIG. 2B is a schematic diagram of the atmosphere side separator 44 viewed from above the engine 10. In FIGS. 2A and 2B, the horizontal direction of the paper surface corresponds to the longitudinal direction of the atmosphere-side separator 44. The atmosphere side separator 44 is formed into a substantially rectangular parallelepiped shape. The atmosphere side separator 44 is attached to the head cover 12 so that the longitudinal direction of the atmosphere side separator 44 is substantially parallel to the crankshaft of the engine 10.

2A and 2B show linear distances L12, L13, and L23. Linear distance L12 indicates the linear distance between the center of the first communication port 441 and the center of the second communication port 442. Linear distance L13 indicates the linear distance between the center of the first communication port 441 and the center of the third communication port 443. Linear distance L23 indicates the linear distance between the center of the second communication port 442 and the center of the third communication port 443. The positions of the first communication port 441, the second communication port 442, and the third communication port 443 are set so that the linear distance L23 is the longest among the linear distances L12, L13, and L23.

3A and 3B are schematic configuration diagrams showing the flow of blow-by gas within the atmosphere side separator 44 in a supercharging operation state. 3A and 3B correspond to FIGS. 2A and 2B, respectively. By ensuring a long linear distance between the second communication port 442 and the third communication port 443 in this way, the third The communication ports 443 are separated. Therefore, even if the flow rate of blow-by gas from the first communication port 441 to the second communication port 442 is larger than the volume of the auxiliary chamber 61, for example, blow-by gas is suppressed from flowing to the third communication port. . Thereby, it is possible to suppress a decrease in detection accuracy of the pressure sensor 70 due to the flow of blow-by gas.

Further, the second communication port 442 is located on one side (on the left side in FIG. 2A) of the atmosphere side separator 44 in the longitudinal direction of the first communication port 441. On the other hand, the third communication port 443 is located on the other side (on the right side in FIG. 2A) of the atmosphere side separator 44 in the longitudinal direction of the first communication port 441. With such a configuration as well, blow-by gas flowing from the first communication port 441 to the second communication port 442 is suppressed from flowing to the third communication port 443, and a decrease in detection accuracy of the pressure sensor 70 can be suppressed.

Note that the straight-line distance L12 between the first communication port 441 and the second communication port 442 is longer than the straight-line distance L13 between the first communication port 441 and the third communication port 443. Thereby, the time required for the blow-by gas to flow in from the first communication port 441 and to flow out from the second communication port 442 can be secured, and the oil component can be sufficiently separated from the blow-by gas.

In the above embodiment, the case 60 is formed separately from the atmosphere side separator 44, but the case 60 is not limited to this, and may be formed integrally with the atmosphere side separator 44, or integrally formed with other parts. may be provided.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

10 Engine 16 Intake passage 20 Turbocharger 20a Compressor 44 Atmospheric side separator (oil separator)
441 First communication port 442 Second communication port 443 Third communication port 51 First communication pipe 52 Second communication pipe 60 Case 61 Sub-chamber 70 Pressure sensor

Claims (4)

In a blow-by gas recirculation system for an internal combustion engine equipped with a supercharger,
an oil separator having a first communication port communicating with a head cover of the internal combustion engine, a second communication port communicating with an intake passage upstream of the compressor of the supercharger, and a third communication port;
a case defining a sub-chamber communicating with the third communication port;
a pressure sensor that detects the pressure within the subchamber;
Equipped with
The straight-line distance between the second communication port and the third communication port is longer than the straight-line distance between the first communication port and the second communication port, and the distance between the first communication port and the third communication port is Longer than the straight line distance between the communication port and
Blow-by gas recirculation device for internal combustion engines. The second communication port is located on one side of the oil separator in the longitudinal direction of the first communication port,
2. The blow-by gas recirculation device for an internal combustion engine according to claim 1, wherein the third communication port is located on the other side of the oil separator in the longitudinal direction of the first communication port. The blow-by gas recirculation for an internal combustion engine according to claim 2, wherein a straight line distance between the first communication port and the second communication port is longer than a straight line distance between the first communication port and the third communication port. Device. a first communication pipe that communicates the third communication port and the subchamber;
The blow-by gas recirculation device for an internal combustion engine according to claim 3, further comprising a second communication pipe communicating the case and the pressure sensor.

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