JP2021161900A - Air bypass feedback device of on-vehicle internal combustion engine with supercharger - Google Patents

Abstract

To provide an air bypass feedback device of an on-vehicle internal combustion engine with a supercharger capable of sufficiently securing a feedback intake air flow rate by smoothly feeding back supercharged intake air to an upstream intake pipe through an air bypass passage.SOLUTION: An air bypass pipe of an air bypass feedback device has: a first part communicated from an outlet of an air bypass valve and extending toward an upstream intake pipe at an upstream side with respect to a compressor; a second part disposed on a connecting portion of the upstream intake pipe and the air bypass pipe and communicated to the upstream intake pipe; and a third part connecting the first part and the second part. The first part and the second part are offset in a vertical direction to an extension direction of the first part of the air bypass pipe, and a rectification portion having an inclined surface facing the first part, is disposed on an inner wall of the third part.SELECTED DRAWING: Figure 2

Description

The present invention passes through an air bypass passage connecting the upstream intake pipe and the downstream intake pipe of the intake pipe so as to bypass the compressor of the supercharger arranged in the intake pipe of the in-vehicle internal combustion engine with a supercharger. The present invention relates to an air bypass return device that returns the intake air in the downstream intake pipe to the upstream intake pipe.

A supercharger for an in-vehicle internal combustion engine generally has a configuration in which a turbine and a compressor are connected to each other via a coaxial shaft. The exhaust gas flow pressure in the exhaust pipe of the internal combustion engine rotates the turbine wheel of the turbine, and the rotation is transmitted to the compressor via the coaxial shaft to rotate the compressor wheel. The compressor wheel is arranged in the intake pipe of the internal combustion engine, and supercharging is performed by supplying the intake air to the engine body in a compressed state by the rotation of the compressor wheel (see, for example, Patent Document 1).

Further, in an in-vehicle internal combustion engine equipped with a supercharger, when the supercharged intake pressure of the downstream intake pipe on the downstream side of the compressor rises sharply compared to the intake pressure downstream of the throttle valve, the supercharged intake air flows back to the compressor side. An air bypass feedback device is provided to prevent this. In the air bypass feedback device, an air bypass passage connecting the upstream intake pipe on the upstream side and the downstream intake pipe on the downstream side of the compressor is formed so as to bypass the compressor of the intake pipe, and an air bypass valve is arranged in the air bypass passage. Will be done. The air bypass valve is a diaphragm type valve, and when the intake pressure in the downstream intake pipe becomes higher than the predetermined pressure than the intake pressure downstream of the throttle valve, the valve body linked with the diaphragm opens to communicate with the air bypass passage. .. As a result, the supercharged intake air in the downstream intake pipe is prevented from returning to the upstream intake pipe via the air bypass passage, and the supercharged intake pressure in the downstream intake pipe is prevented from becoming higher than necessary.

Japanese Unexamined Patent Publication No. 2016-11655

In an in-vehicle internal combustion engine, when a supercharger is provided, the intake system and exhaust system piping of the engine body are coupled to the supercharger, and the air bypass passage piping of the air bypass feedback device is the intake system. Combined with the plumbing. Therefore, especially in a vehicle where there is no space in the engine room, it becomes difficult to pipe the air bypass passage to the upstream intake pipe, and a step is generated at the joint from the air bypass passage to the upstream intake pipe to flow the intake air. There is a problem that the direction changes and the return intake air flow rate decreases.

Therefore, an object of the present invention is an air bypass feedback device for an in-vehicle internal combustion engine with a supercharger capable of smoothly returning the supercharged intake air to the upstream intake pipe via an air bypass passage to secure a sufficient return intake air flow rate. Is to provide.

The air bypass feedback device of the present invention is coupled to the upstream intake pipe on the upstream side and the downstream intake pipe on the downstream side of the position where the compressor of the supercharger is arranged, which is arranged in the intake pipe of the in-vehicle internal combustion engine with a supercharger. Then, the air bypass pipe having an air bypass passage internally connecting the inside of the upstream intake pipe and the inside of the downstream intake pipe and the intake air in the downstream intake pipe are returned to the inside of the upstream intake pipe via the air bypass passage when the valve is opened. An air bypass return device including an air bypass valve, wherein the air bypass pipe communicates with the outlet of the air bypass valve and extends toward the upstream intake pipe, and the upstream intake pipe. A second portion provided at a joint portion between the air bypass pipe and the air bypass pipe and communicating with the upstream intake pipe, and a third portion connecting the first portion and the second portion. The first portion and the second portion of the air bypass pipe are offset in a direction perpendicular to the extension direction of the first portion of the air bypass pipe, and the third portion The inner wall of the is provided with a rectifying portion having an inclined surface facing the first portion.

According to the air bypass feedback device of the present invention, the first portion that communicates from the outlet of the air bypass valve and extends toward the upstream intake pipe is provided at the joint portion between the upstream intake pipe and the air bypass pipe and is upstream. Since the inner wall of the third portion connecting to the second portion communicating with the intake pipe is provided with a rectifying portion having an inclined surface facing the first portion, the inclined surface of the rectifying portion for intake air is provided. It is possible to smoothly return to the upstream intake pipe along the above, whereby a sufficient return intake flow rate can be secured.

It is a figure which shows the intake system of the internal combustion engine including the air bypass feedback device of the Example of this invention. It is a figure which shows the cross section of the air bypass pipe and the air bypass valve of the air bypass return device of FIG. It is a figure which shows the positional relationship between the bottom wall part including the rectifying part of the air bypass return device of FIG. 1 and the upstream intake pipe. It is a flow velocity vector diagram which shows the flow of the intake air from the outlet part of an air bypass passage to the inside of an upstream intake pipe when a rectifying part is provided. It is a flow velocity vector diagram which shows the flow of the intake air from the outlet part of an air bypass passage to the inside of an upstream intake pipe when a rectifying part is not provided.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an intake system of an internal combustion engine including the air bypass feedback device of the present invention. FIG. 2 shows a cross section of the air bypass pipe and the air bypass valve of the air bypass return device.

In the intake system shown in FIGS. 1 and 2, the compressor 1 of the supercharger is coupled to each of the upstream intake pipe 2 and the downstream intake pipe 3. The upstream intake pipe 2 is an intake pipe on the upstream side of the compressor 1, and the downstream intake pipe 3 is an intake pipe on the downstream side of the compressor 1. An intercooler and a throttle valve (not shown) are provided in this order in the intake system downstream of the downstream intake pipe 3. An air bypass return device 10 is provided on the upstream side of the throttle valve of the downstream intake pipe 3. The air bypass return device 10 has an air bypass pipe 16 that forms an air bypass passage 19 described later, and the passage inlet portion 16a of the air bypass pipe 16 is coupled to the downstream intake pipe 3 via a connecting pipe 11. .. The inside of the connecting pipe 11 forms a part of the air bypass passage 19. Further, the passage outlet portion 16b of the air bypass pipe 16 is connected to a connecting portion 4 provided in the upstream intake pipe 2, and the connecting portion 4 is formed so as to project cylindrically from the outer surface of the upstream intake pipe 2.

The air bypass return device 10 includes an air bypass valve 15 in addition to the air bypass pipe 16. The air bypass pipe 16 includes a long and flat bottom wall portion 17 extending in the intake flow direction and an upper wall portion 18 covering the bottom wall portion 17. The upper wall portion 18 forms an air bypass passage 19 with the bottom wall portion 17. The upper wall portion 18 has a shape curved in the lateral direction, one end in the longitudinal direction forms the above-mentioned passage entrance portion 16a together with one end of the bottom wall portion 17, and the other end is described above together with the other end of the bottom wall portion 17. The passage exit portion 16b is formed.

The air bypass passage 19 is a passage via the air bypass valve 15. A part of the ceiling surface of the upper wall portion 18 is opened, and an air bypass valve 15 is provided in the opening via the holder 21. Further, an inner wall portion 18a is formed in the vicinity of the opening of the upper wall portion 18. The inside of the air bypass pipe 16 is partitioned by the inner wall portion 18a, and the air bypass passage 19 passes through the inside of the air bypass valve 15. The air bypass valve 15 is arranged at a position lower than the highest position on the ceiling surface of the inner wall of the upstream intake pipe 2 in the vertical direction.

The air bypass valve 15 is a diaphragm type valve, and has a valve body 15b that moves together with the diaphragm 15a to open and close the air bypass passage 19. Further, the air bypass valve 15 has a pressure chamber 15c, and the pressure chamber 15c is supplied with intake air downstream from the throttle valve in the downstream intake pipe 3. The diaphragm 15a is provided at a position sandwiched between the pressure chamber 15c and the air bypass passage 19. The valve body 15b of the air bypass valve 15 is normally closed by abutting the tip of the inner wall portion 18a, thereby blocking the air bypass passage 19. However, for example, when the intake pressure of the air bypass passage 19 on the downstream intake pipe 3 side of the throttle valve closing valve becomes higher than the intake pressure downstream of the throttle valve supplied into the pressure chamber 15c, the diaphragm 15a becomes the diaphragm 15a. By moving to the upper pressure chamber 15c side, the valve body 15b opens and communicates with the air bypass passage 19.

The portion of the air bypass pipe 16 extending from the outlet of the air bypass valve 15 toward the connecting portion 4 of the upstream intake pipe 2 is the first portion, and is provided at the connecting portion between the connecting portion 4 and the air bypass pipe 16. The portion of the air bypass pipe 16 communicating with the connecting portion 4 is the second portion. The first portion and the second portion may be provided at different positions from each other.

The plane position of the bottom wall portion 17 of the air bypass pipe 16 (the bottommost position of the inner wall of the first portion) is the lowest position of the inner wall surface connected to the connecting portion 4 of the upstream intake pipe 2 (the bottommost position of the inner wall of the second portion). ) Slightly lower and offset. Therefore, as can be seen from the cross section of the air bypass pipe 16 shown in FIG. 2, the upper wall portion 18 is formed so that the other end is connected to the end portion of the connecting portion 4. That is, the other end portion of the upper wall portion 18 is greatly curved upward toward the passage outlet of the air bypass passage 19 and is connected to the end portion of the connecting portion 4.

On the other hand, a rectifying portion 20 is formed at the other end portion of the bottom wall portion 17 (that is, a third portion connecting the first portion and the second portion). As can be seen from FIGS. 2 and 3, the rectifying unit 20 is a plate-shaped member having an inclined surface. The inclined surface of the rectifying portion 20 is inclined from the plane position of the bottom wall portion 17 toward the lowest position of the inner wall surface of the end portion of the connecting portion 4. That is, the bottom wall surface in the air bypass pipe 16 is made continuous from the plane position of the bottom wall portion 17 to the bottom surface of the end inner wall of the connecting portion 4 without a step. In this embodiment, the rectifying portion 20 is formed integrally with the bottom wall portion 17, but may be formed as a separate body from the bottom wall portion 17. Further, the rectifying portion 20 may be a protrusion having a slope facing the plane position of the bottom wall portion 17.

The compressor 1 is connected to the turbocharger turbine 6 by a shaft (not shown) coaxial with the turbocharger turbine 6. Further, an actuator 7 for driving a waist gate valve (not shown) of the turbine 6 is supported by a support member (not shown) on the compressor 1.

In the air bypass return device of the present invention having such a configuration, when the valve body 15b of the air bypass valve 15 is opened, the air bypass passage 19 is communicated with the air bypass valve 15, so that one of the supercharged intake air in the downstream intake pipe 3 is used. The portion flows through the air bypass passage 19 and is supplied to the upstream intake pipe 2. Specifically, the supercharged intake air flowing in from the passage inlet of the air bypass passage 19 proceeds through the air bypass pipe 16 to the inner wall portion 18a, and goes toward the air bypass valve 15 along one wall surface of the inner wall portion 18a, and air. It passes between the valve body 15b of the bypass valve 15 and the tip of the inner wall portion 18a, and then returns to the inside of the air bypass pipe 16 along the other wall surface of the inner wall portion 18a. Then, the supercharged intake air goes through the air bypass pipe 16 toward the passage outlet of the air bypass passage 19. The supercharged intake air travels linearly on the bottom wall portion 17, flows upward along the inclined surface of the rectifying portion 20 at the passage outlet portion 16b, and flows into the upstream intake pipe 2 via the connecting portion 4.

The flow of intake air from the passage outlet 16b to the inside of the upstream intake pipe 2 when the rectifying unit 20 is provided is as shown in FIG. 4 by a flow velocity vector diagram, while the passage outlet when the rectifying unit 20 is not provided. The flow of intake air from 16b to the inside of the upstream intake pipe 2 is as shown in FIG. 5 by a flow velocity vector diagram.

As can be seen from the flow velocity vector diagrams shown in FIGS. 4 and 5, when the rectifying unit 20 is provided, the supercharged intake air (arrow) flows smoothly as a whole along the inclined surface of the rectifying unit 20 and passes through the passage. Proceed to the exit. On the other hand, when the rectifying unit 20 is not provided, a part of the supercharged intake air (arrow) that flows collides with the end wall surface 4a of the connecting portion 4 to generate a vortex, which is upward along the end wall surface. It moves to and adversely affects the flow of supercharged intake air that does not collide with the end wall surface. That is, the region where the supercharged intake air that does not collide with the end wall surface 4a is obstructed and smoothly flows is reduced.

As described above, in the embodiment, when the rectifying unit 20 is provided, a smoother flow of the supercharged intake air can be realized, so that the flow rate can be increased per unit time as compared with the case where the rectifying unit 20 is not provided. can.

Further, in the embodiment, as described above, the air bypass valve 15 is arranged above the air bypass pipe 16 at a position lower than the highest position on the inner wall ceiling surface of the upstream intake pipe 2. This has the effect that the air bypass valve 15 does not protrude significantly upward in the intake system.

1 ... Compressor, 2 ... Upstream intake pipe, 3 ... Downstream intake pipe, 4 ... Connecting part, 10 ... Air bypass feedback device, 11 ... Connecting pipe, 15 ... Air bypass valve, 15a ... Diaphragm, 15b ... Valve body, 15c ... Pressure chamber, 16 ... air bypass pipe, 17 ... bottom wall part, 18 ... upper wall part, 19 ... air bypass passage, 20 ... rectifying part, 21 ... holder.

Claims (4)

The upstream intake pipe on the upstream side and the downstream intake pipe on the downstream side of the position where the compressor of the supercharger is arranged, which are arranged in the intake pipe of the in-vehicle internal combustion engine with a supercharger, are connected to each other in the upstream intake pipe and in the downstream. An air bypass pipe that has an air bypass passage that connects the inside of the intake pipe,
An air bypass return device including an air bypass valve that returns the intake air in the downstream intake pipe to the upstream intake pipe via the air bypass passage when the valve is opened.
The air bypass pipe is provided at a first portion that communicates with the outlet of the air bypass valve and extends toward the upstream intake pipe, and a joint portion between the upstream intake pipe and the air bypass pipe, and is provided at the upstream. It has a second portion communicating with the intake pipe and a third portion connecting the first portion and the second portion.
The first portion and the second portion of the air bypass pipe are offset in a direction perpendicular to the extension direction of the first portion of the air bypass pipe, and are offset on the inner wall of the third portion. Is an air bypass feedback device characterized in that a rectifying section having an inclined surface facing the first portion is provided. The bottom position of the inner wall in the vertical direction of the first part is lower than the bottom position of the inner wall in the vertical direction of the second part.
The air bypass according to claim 1, wherein the inclined surface of the rectifying unit is an inclined surface that climbs from the bottommost position of the inner wall of the first portion to the bottommost position of the inner wall of the second portion. Return device. The air bypass return device according to claim 1, wherein the air bypass valve is arranged at an upper position of the air bypass pipe and at a position lower than the highest position of the inner wall of the upstream intake pipe in the vertical direction. The air bypass valve opens when the intake pressure on the upstream side of the throttle valve of the internal combustion engine in the downstream intake pipe becomes equal to or higher than a predetermined pressure than the intake pressure on the downstream side of the throttle valve to communicate with the air bypass passage. The air bypass feedback device according to claim 1, wherein the air bypass feedback device is characterized.

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