JP3358507B2 - Intake device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine utilizing an inertial supercharging effect.

[0002]

2. Description of the Related Art It is known that, when an intake passage length, an intake pipe diameter, and the like are appropriately selected, inertial supercharging is realized in a specific engine rotation region, intake charging efficiency is increased, and engine output is improved. In order to achieve such inertia supercharging at each engine speed, various proposals have been made to change the intake passage length. For example, Japanese Utility Model Laid-Open Publication No. 63-96230 discloses a cylindrical surge tank disposed in a cylindrical case, and an annular space formed by the case and the surge tank is used as a part of an intake passage. Is disclosed.

In this intake device, the surge tank is
The intake air flowing in the axial direction is caused to flow out from the opening formed in the side wall, whereby the length of the annular space used as the intake passage changes continuously by rotating the surge tank, It is possible to realize inertial supercharging from low rotation to high rotation.

[0004]

In the above-described intake device, the size of the engine rotation range in which inertial supercharging can be realized is proportional to the rotation angle of the surge tank. The rotation angle of the surge tank is an angle between the case where the opening of the side wall is located to minimize the effective length of the annular space and the case where the opening length of the annular space is located to maximize the effective length of the annular space. is there. That is, the rotation angle of the surge tank cannot be greater than 360 ° minus the opening angle of the opening (the angle in the rotation direction). In the above-described prior art, the area of the opening formed in the side wall of the surge tank is made relatively large in order to allow a large amount of intake air to pass at the time of high engine rotation, that is, the opening angle of the opening is made large. Therefore, the rotation angle of the surge tank is reduced, and accordingly, the engine rotation region in which inertial supercharging can be realized is narrowed.

Accordingly, it is an object of the present invention to provide a first intake passage portion having a cylindrical member, wherein a first intake passage portion forming a part of an intake system extends axially inside the cylindrical member. A second intake passage portion forming a part of the intake system on the downstream side is formed so as to extend in the circumferential direction of the tubular member by two side walls disposed adjacent to the outside of the tubular member in the axial direction, and has a cylindrical shape. The member is formed with an opening for communicating the first intake passage portion and the second intake passage portion. The opening has a relatively large area, and is opened by rotating the cylindrical member around an axis. In the intake device of the internal combustion engine in which the portion moves around the axis and the effective length in the second intake passage portion changes, the engine rotation region in which inertial supercharging can be realized is enlarged as compared with the related art without increasing the size. That is.

[0006]

According to a first aspect of the present invention, there is provided an intake system for an internal combustion engine according to the present invention, which has a cylindrical member, and a first intake passage portion forming a part of an intake system is provided with the cylindrical member. A second intake passage portion extending inward in the axial direction and forming a part of the intake system downstream of the first intake passage portion is formed so as to extend circumferentially outside the cylindrical member. An opening for communicating the first intake passage portion and the second intake passage portion is formed in the tubular member, and the opening has a relatively large opening area. In the intake device for an internal combustion engine, in which the opening moves about the axis by rotating about the axis, and the effective length in the second intake passage portion changes, when the effective length is equal to or more than a predetermined length, The opening area of the opening is gradually reduced from the downstream side of the intake air. Characterized by comprising a shield member that.

[0007]

FIG. 1 is a schematic sectional view showing an intake device for an internal combustion engine according to the present invention. In the figure, 1 is a four-cylinder engine main body, 2 is a piston, 3 is a combustion chamber, 4 is an intake valve, 5 is an intake port, 6 is an exhaust valve, 7 is an intake passage branch pipe,
Reference numeral 8 denotes an intake passage length varying device. FIG.
FIG. 2 is a sectional view taken along the line AA in FIG. 1, showing a section of the variable intake passage length device 8. Referring to FIGS. 1 and 2, the variable intake passage length device 8 includes a fixed cylindrical case 11 and a cylindrical tubular member 12 concentrically arranged in the case 11. The space between the case 11 and the tubular member 12 is divided into four in the axial direction by three substantially C-shaped partition walls 13. Each of the four divided spaces is closed at one end by an end wall 15 and communicates with each combustion chamber 3 via an intake port 5 for each cylinder at the other end.

The cylindrical member 12 is formed with four openings 16 opening to the above-mentioned four spaces. The opening 16 may be a single elongated opening that opens in all four spaces in order to facilitate processing of the tubular member 12. The side surfaces at both ends of the cylindrical member 12 slide with respect to the side wall of the case 11 positioned at the same position as the annular end surface of the partition wall 13, and the intake air flows only through the opening 16 of the cylindrical member 12. Into the four spaces. Both ends of the case 11 are closed, and an intake pipe 17 is connected to one end. A throttle valve 18 is arranged in the intake pipe 17.

The end of the cylindrical member 12 on the side of the intake pipe 17 is open in its shape, but the opposite end is connected to the small-diameter cylindrical portion 12a. External teeth (not shown) are formed on the outer surface of the small diameter cylindrical portion. A gear 21a meshing with the external teeth is provided, and a drive shaft of the first drive device 21 is connected to the gear 21a through an end of the case 11. Thereby, the cylindrical member 12 is rotatable around the axis with respect to the fixed case 11 and the intake pipe 17 by the first driving device 21.

In such a configuration, the space 9 in the tubular member 12 is the first intake passage portion 9 forming a part of an intake system functioning as a surge tank, and extends in the axial direction of the tubular member 12. are doing. Further, the above-mentioned four spaces are respectively cylindrical members 1 as second intake passage portions 14 which form a part of the intake system on the downstream side of the intake system expansion section such as a surge tank.
2 and extends in the circumferential direction. The first intake passage portion and the second intake passage portion communicate with each other through an opening 16 formed in the tubular member 12. Thereby, the intake air flows from the intake pipe 17 through the throttle valve 18 into the first intake passage portion 9, flows through the opening 16 into each second intake passage portion 14, and flows into each of the intake passage branch pipes 7 and It is supplied to each cylinder via each intake port 5. In the variable intake passage length device 8, the second intake passage portions 14 are adjacent to each other, but the respective intake passage branch pipes 7 enable connection of the cylinders separated from each other to the intake port 5.

In the present embodiment, a cylindrical shielding member 30 which is in contact with the inside of the cylindrical member 12 is disposed in the space 9 within the cylindrical member 12. An opening 31 having the same shape as each opening 16 of the tubular member 12 is formed in the shielding member 30. The end of the shielding member 30 on the side of the intake pipe 17 is open similarly to the cylindrical member 12, but the opposite end is a disc located concentrically inside the small-diameter cylindrical portion 12 a of the cylindrical member 12. It is closed by the member 30a. An operating shaft 30b is connected to the center of the disc member 30a, and the operating shaft 30b protrudes to the outside through an end of the case 11. A gear 30c is attached to an end of the operating shaft 30b. The gear 22a meshed with the gear 30c
The second driving device 22 is connected to the gear 22a. Thereby, the shielding member 30 is rotatable around the axis with respect to the fixed case 11 and the intake pipe 17 by the second driving device 22. Shielding member 30
A bearing 41 is disposed between the disc member 30a and the small-diameter portion 12a of the tubular member 12, so that the tubular member 12 and the shielding member 30 can freely rotate with respect to each other. Further, a bearing 42 is also arranged between the operating shaft 30 b of the shielding member 30 and the end of the case 11.

According to the specifications of the engine intake system, it is possible to obtain an inertia supercharging effect in which the intake charging efficiency is improved at a specific engine speed. The specific engine speed N is represented by the intake system specifications expressed by the following equation. N = 30C (S / L · Vh) ^1/2 / 2π where C is the sonic speed, S is the intake passage cross-sectional area, L is the intake passage length, and Vh is the engine stroke volume.

The variable intake passage length device 8 of this embodiment rotates the tubular member 12 clockwise in FIG. 1 as the engine speed decreases, based on the engine speed detected by a rotation sensor or the like. In addition, the higher the engine speed, the more counterclockwise in FIG. Thus, as the engine speed decreases, the opening 1 of the tubular member 12 decreases.
6 is separated from the intake passage branch pipe 7 side, and the effective length of each second intake passage portion 14 is increased. That is, the lower the engine speed, the longer the intake passage length L in the intake system.

FIG. 1 shows a state in which the opening 16 of the tubular member 12 is rotated clockwise to the maximum until it contacts the end wall 15, and FIG. Part wall 1
5 shows a state in which it has been rotated to the maximum in a counterclockwise direction until it touches 5. The opening 16 of the tubular member 12 has a relatively large opening area to allow a large amount of intake air to pass at the time of high engine rotation. Since the width of the opening 16 is regulated by the width of the second intake passage portion 14, in order to secure such an opening area, the circumferential length of the opening 16 must be necessarily increased. That is, the opening angle TA1 of the opening 16 must be relatively large.

As described above, conventionally, the engine rotation range in which inertial supercharging can be realized is a change range of the effective intake passage length of the second intake passage portion 14 due to the opening portion 16 of the tubular member 12, that is, a cylindrical shape. The rotation angle of the member 12 (about 360 °-
TA1).

In the present embodiment, a shielding member 30 is disposed inside the tubular member 12, and an opening 31 of the shielding member 30 is used to minimize the effective intake passage length of the second intake passage portion 14. At the time of high rotation (FIG. 3), the cylindrical member 12
Opening 16. As a result, a large amount of intake air at the time of high engine rotation passes through a relatively large opening area in the opening 16 of the tubular member 12, and sufficient ventilation performance is guaranteed.

FIG. 4 shows the shielding member 30 with respect to the engine speed.
4 is a map showing an angle difference between the cylinder member 12 and the cylindrical member 12 (for example, based on the high engine speed in FIG. 3). As described above, the tubular member 12 is gradually rotated clockwise as the engine speed decreases. As shown in the map of FIG. 4, after the predetermined engine speed has been reached and the effective length of the second intake passage portion 14 has reached the predetermined length, the angle difference is gradually increased from zero. That is, after this time, the shielding member 30
The opening 31 of the shielding member 30 precedes the opening 16 of the cylindrical member 12 by being gradually rotated clockwise more than the cylindrical member 12.

Thus, so to speak, the second intake passage portion 14
After the effective length of the cylindrical member 12 becomes the predetermined length, the cylindrical member 12
The opening area of the opening 16 is gradually reduced by the shielding member 30 from the intake downstream side. At this time, the engine speed is not so high, and the required intake air amount is reduced. Therefore, even if the opening area of the opening 16 of the tubular member 12 is reduced, sufficient ventilation performance is secured.

It can be considered that the effective length of the second intake passage portion 14 starts from the center of the opening in the opening 16 of the tubular member 12, and thus the opening of the tubular member 12 decreases as the engine speed decreases. When the opening area of the portion 16 is reduced from the downstream side of the intake air, the center of the opening of the opening 16 is gradually separated from the intake passage branch pipe 7 side,
The effective length of the intake passage section 14 can be extended.
This makes it possible to achieve inertial supercharging even at a lower rotation speed than in the past, and to expand the engine rotation range in which inertial supercharging can be realized.

The dotted line in the map of FIG. 4 indicates the angle difference at the time of high engine load, and the angle difference is smaller than the solid line. This is because the required air amount increases as the engine load increases at the same engine speed, and the decrease in the opening area at the opening 16 of the tubular member 12 is reduced, so that the ventilation performance is ensured. ing. Conversely, when the engine is under low load, the required air volume decreases,
The angle difference may be increased so as to increase the decrease in the opening area of the opening 16 of the tubular member 12.

In this embodiment, the shielding member 30 has the opening 31 having the same size as the opening 16 of the cylindrical member 12, but this does not limit the present invention. The opening angle TA2 of 31 can be considerably increased clockwise in FIG. That is,
The shielding member 30 may be, at a minimum, a curved plate member having a width enough to reduce the opening area of the opening 16 of the cylindrical member 12.
It is also possible to arrange them outside of 2.

Further, in the present embodiment, the first intake passage portion functions as a surge tank, but this does not limit the present invention. For example, the second intake passage portion around the cylindrical member , And such a structure may be provided for each cylinder.

[0023]

As described above, according to the intake system for an internal combustion engine according to the present invention, the first intake passage portion forming a part of the intake system extends in the axial direction inside the cylindrical member, and the first intake passage portion is formed. A second intake passage portion that forms a part of the intake system downstream of the passage portion is formed to extend in the circumferential direction outside the tubular member, and the first intake passage portion and the second intake passage portion are formed in the tubular member. An opening for communicating with the passage portion is formed, the opening has a relatively large opening area, and the opening moves around the axis by rotating the cylindrical member around the axis, so that the second intake passage is formed. In the intake device of the internal combustion engine in which the effective length of the portion changes, when the effective length of the second intake passage portion is equal to or longer than a predetermined length, the shielding member gradually increases the opening area of the opening from the intake downstream side. Decrease. Accordingly, when the engine is running at a high engine speed where the effective length of the second intake passage portion is shorter than the predetermined length, a large amount of intake air can be passed through the opening having a relatively large opening area. In addition, when the engine is running at a low engine speed where the effective length of the second intake passage portion is longer than the predetermined length, the intake air amount is reduced. Therefore, there is no problem even if the opening area of the opening is gradually reduced from the intake downstream side. In this way, it is possible to move the center of the opening area, which is a reference for the effective length of the second intake passage portion, to the intake upstream side without increasing the size of the intake device, which is equivalent to the effective length of the second intake passage portion. And the engine rotation range in which inertial supercharging can be realized can be expanded as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an intake device for an internal combustion engine according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic sectional view showing an intake passage length varying device at the time of high engine rotation.

FIG. 4 is a map showing an angle difference between a shielding member and a cylindrical member with respect to an engine speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine main body 4 ... Intake valve 5 ... Intake port 7 ... Intake passage branch pipe 8 ... Intake passage length variable device 9 ... First intake passage part 12 ... Cylindrical member 14 ... Second intake passage part 16 ... Opening 30 ... Shielding member 31 ... opening

Claims (1)

(57) [Claims] 1. A first intake passage portion having a cylindrical member and forming a part of an intake system extends axially inside the cylindrical member, and the first intake passage portion is provided on a downstream side of the first intake passage portion. A second intake passage portion forming a part of an intake system is formed so as to extend in a circumferential direction outside the tubular member, and the tubular member has the first intake passage portion and the second intake passage portion. The opening has a relatively large opening area, and the opening is moved around the axis by rotating the cylindrical member around the axis, so that the second opening is formed. An intake device for an internal combustion engine in which an effective length in an intake passage portion changes, comprising a shielding member that gradually reduces the opening area of the opening from the intake downstream side when the effective length is equal to or longer than a predetermined length. An intake device for an internal combustion engine.