JP3046699B2 - 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 system for an internal combustion engine, and more particularly to an intake system of an axial length equal branch type.

[0002]

2. Description of the Related Art Conventionally, as a kind of intake device in an internal combustion engine, the intake passage length has been set for each cylinder in order to uniformly distribute intake air to each cylinder and to ensure uniform intake inertia supercharging effect. Equal axial flow equal length branch type intake devices are known, for example, from Japanese Utility Model Laid-Open No. 60-88062 and Japanese Patent Laid-Open No. 4-76263.

[0003] The supercharging effect due to the intake inertia effect is as follows.
A negative pressure wave generated at the intake port in the early stage of opening of the intake valve propagates at the sonic speed in the branch portion toward the upstream, and this negative pressure wave is inverted into a positive pressure wave at the gathering portion and propagates at the sonic speed downstream in the branch portion. Then, by arriving at the intake port immediately before closing the intake valve, the positive pressure wave pushes the intake air into the combustion chamber, and the rotational speed of the internal combustion engine that exerts its effect is determined by the branch length. Become.

[0004]

By the way, in the intake device of the axial flow equal length branch type, it is necessary to increase the branch length in order to exhibit the effect of improving the torque in the middle and low speed range. There is a problem that the distance from the engine body to the throttle body becomes longer, it becomes difficult to secure the strength of the branch portion, the throttle body is easily vibrated, and a compact structure cannot be achieved.

It is also conceivable to secure the branch length by arranging the branch portion from below to above. However, in this case, since the intake air flow in the throttle rises, a normal lateral flow or downstream flow type is used. There is a problem that compatibility with the throttle is lost.

The present invention has been made in view of the above-mentioned conventional problems, and is intended to solve the problems of the strength and vibration of the throttle body while securing the length of the branch portion, and to realize a compact axial flow type branch type. It is an object to provide an intake device.

[0007]

According to the present invention, a throttle body is provided on one side of an intake port side of an engine body and supported by the engine body, and a branch portion having one end connected to each intake port is provided with a throttle. Curved downward so as to pass through the outside of the body, provided a collecting part at the other end, and connected an air cleaner arranged at the upper part of the branch part and the throttle body with an intake introduction pipe passing through the center space of the branch part, The throttle body and the collecting part are connected by an intake pipe.

[0008]

According to the present invention, the branch length can be secured by largely bending the branch portion downward from the intake port and extending downward, and the throttle body is supported by the engine body. Therefore, the support rigidity is high and there is no danger of causing a vibration problem, and the intake pipe extending from the throttle body is connected to the gathering portion at the tip of the branch portion. Can be extended longer without causing problems,
The air cleaner is located above the branch, and the air cleaner and the throttle body are connected by the intake pipe that passes through the center space of the branch, so the air cleaner, the branch, the throttle body, and the assembly are connected to the engine body. Can be collectively arranged on one side, and can be configured compactly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an engine body, which is mainly composed of a cylinder block 2 and a cylinder head 3. Reference numeral 4 denotes a plurality of intake ports formed for each cylinder (four cylinders in the illustrated example) on one side of the cylinder head 3.
An intake manifold 6 constituting a downstream portion of the branch portion 5 is connected. The intake manifold 6 is formed so as to extend obliquely upward from the intake port 4 and then bend obliquely downward, and has a connection mouthpiece 7 attached to the end thereof.

Reference numeral 8 denotes an intake pipe unit, and a branch pipe 10 having an upper end connected to the connection base 7 via a rubber hose 9;
A collecting part 11 to which the lower end of the branch pipe 10 is connected, an inlet pipe 12 curved obliquely upward from the lower end of the collecting part 11, and a connection base 13 attached to the tip of the inlet pipe 12.
It consists of. The branch pipe 10 constitutes an upstream part of the branch part 5. The collecting part 11 has a pent roof shape, and four branch pipes 10 extend upward from the roof part.

Reference numeral 14 denotes a throttle body, which is disposed on one side of the cylinder block 2 on the side of the intake port 4 and is fixedly supported by a boss 16 protruding above the cylinder block 2 via a bracket 15. The branch portion 5 composed of the intake manifold 6 and the branch pipe 10 is curved downward so as to surround the outside of the throttle body 14, and the collecting portion 11 at the lower end thereof forms a throttle body 14.
It is arranged below. The throttle body 14 is disposed in such a manner that the intake air flows obliquely downward toward the cylinder block 2 side, and an intake pipe whose tip is bent so as to point obliquely downward toward the outside of the cylinder block 2 at its outlet. 17 are connected. The tip of the intake pipe 17 is connected to a connection base 13 of the inlet pipe section 12 of the intake pipe unit 8 via a rubber hose 18. Intake pipe 1
7 is also fixedly supported by a boss 20 projecting below the cylinder block 2 via a mounting bracket 19 fixed to the same.

An air cleaner 21 is provided above the intake manifold 6 and is mounted and supported on the intake manifold 6. The distal end of an intake delivery pipe 22 that extends outward from the air cleaner 21 obliquely downward along the branch pipe 10 is bent toward the engine body 1, and an intake introduction hose 23 connected to the distal end of the intake delivery hose 23 is connected to the branch pipe 10. Is connected to the inlet portion 14a of the throttle body 14 through a space 25 (see FIG. 2) formed in the center of the throttle body 14. An intake introduction pipe 24 is constituted by the intake introduction pipe 22 and the intake introduction hose 23.

According to the above configuration, the intake manifold 6
And a branch section 5 composed of a branch pipe 10 and an intake port 4
Since it is largely curved downward and extends long downward, it is possible to easily secure an arbitrary branch length at which the intake inertia effect can be obtained during a middle to low speed operation. Further, since the throttle body 14 and the intake pipe 17 are arranged near the engine main body 1 and are supported by the engine main body 1, the support rigidity is high, and there is no possibility of causing a vibration problem. Further, the air cleaner 21 is disposed above the branch portion 5, and the air cleaner 21 and the throttle body 14 are connected to the branch portion 5.
The air cleaner 21, the branch portion 5, the throttle body 14, and the collecting portion 11 can be collectively arranged near the engine main body 1 because they are connected to each other by the intake inlet pipe 24 passing through the central space 25. In addition, since it is arranged near the engine body 1, it is easy to secure the strength against vibration, and the weight can be reduced.

The upper and lower ends of the intake pipe unit 8 are connected via rubber hoses 9 and 18 to the intake manifold 6 fixed to the engine body 1 and the intake pipe 17, and are elastically connected to the engine body 1. Therefore, the strength of the intake pipe unit 8 against vibration can be easily secured, the weight can be reduced accordingly, the noise can be reduced, and the engine body 1 which is a heat source can be separated. This is advantageous from the viewpoint of the intake charging efficiency.

Further, the direction of intake air flow in the throttle body 14 is obliquely downward, so that compatibility with a normal lateral flow type or down flow type throttle can be ensured. In addition, it is a mounting structure that does not require stays or brackets as a collision measure,
Inexpensive configuration.

In the above-described embodiment, an example is shown in which the intake manifold 6 is connected to the intake port 4 and the branch pipe 10 is connected to the intake manifold 6, but a connection base 26 is attached to the intake port 4 as shown in FIG. Alternatively, the branch pipe 10 may be directly connected to the branch pipe 10 by a rubber hose 27.

[0018]

According to the intake device for an internal combustion engine of the present invention,
As described above, the branch portion is largely curved from the intake port and extends downward downward, so that a desired branch length can be secured, and since the throttle body is supported by the engine body, the support rigidity is achieved. There is no danger of causing vibration problems, and since the throttle body and the gathering portion at the tip of the branch portion are connected by an intake pipe, the branch portion is not supported and no strength problem occurs as described above. The air cleaner can be extended for a long time, and the air cleaner is arranged at the upper part of the branch part, and this air cleaner and the throttle body are connected by the intake pipe that passes through the center space of the branch part. The throttle body and the collecting part can be arranged near one side of the engine body and can be compactly constructed. The flow direction of the intake air in the can can be ensured compatibility with conventional throttle body for a downward.

Therefore, in the intake device of the axial flow equal length branch type, it is possible to solve the problems of the strength and the vibration of the throttle body while securing the branch length, and to improve the torque in the middle to low speed region with a compact structure. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of an intake device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional front view of a branch portion and a collecting portion of the embodiment.

FIG. 3 is a vertical sectional side view showing a modified example of a connection portion between the branch portion and the intake port in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 4 Intake port 5 Branch part 11 Assembly part 14 Throttle body 17 Intake pipe 21 Air cleaner 24 Intake introduction pipe 25 Center space of branch part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 27/00 F02M 35/104

Claims (1)

(57) [Claims] 1. A throttle body is disposed on one side of an intake port side of an engine body and supported by the engine body so that a branch portion having one end connected to each intake port passes outside the throttle body. Curved downward and provided a collecting part at the other end, and connected the air cleaner and throttle body located above the branch part with an intake pipe that passes through the center space of the branch part, and connected the throttle body and the collecting part to the intake pipe An intake device for an internal combustion engine, characterized by being connected by: