JPH04284154A - Silencer device of internal combustion engine - Google Patents

Abstract

PURPOSE:To enable rational arrangement of a silencer device in an engine room without reducing the space. CONSTITUTION:In a silencer device where a resonance silencer chamber 4 communicated with an intake passage 3 of an internal engine 13, side branch resonance pipe or interference pipe are arranged, an improvement is made such that the resonance silencer chamber 4 and the side branch resonance pipe or the interference pipe are disposed inside the hollow space of a reinforce frame 15 mounted on the rear surface of an engine hood 14. The hollow inside may be used as it is as a resonance silencer chamber 4 or the like, and after filling a separate hollow member in the hollow space it may be used as the resonance chamber or the like.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a silencing device installed in an internal combustion engine such as an internal combustion engine of an automobile, a ship, etc., which is provided with an engine hood above, in order to eliminate intake noise generated in the intake pipe. It is related to.

0002

[Prior Art] Conventionally, as this type of silencer,
A resonance-type muffling device with a box-shaped resonant muffling chamber that communicates with the intake pipe through a communication hole; ■ A side-branch resonance muffler with a side-branch resonance pipe whose one end communicates with the intake pipe. Interference-type silencers are known, in which interference pipes are installed at both ends of the intake pipe, and these are installed near the intake pipe in the engine room with a space secured. There is.

0003

However, the space in the engine room is limited, and the area near the intake pipe is especially narrow because many parts and pipes are crowded together. On the other hand, in the resonance type muffler of item (1) above, the volume of the resonant muffling chamber is large, and in the side branch resonance type or interference type muffler of The length of the tube is quite large, reaching more than 100 cm, especially when the silencing frequency is low. For this reason, it has been difficult to secure space for installing these silencers near the intake pipe in the engine room.

SUMMARY OF THE INVENTION An object of the present invention is to provide a silencing device that solves the above-mentioned problems and can be rationally installed in an engine room without narrowing its space.

[0005]

[Means for Solving the Problems] In order to achieve the above object, a muffling device for an internal combustion engine according to the present invention provides a resonant muffling chamber, a side branch resonant pipe or an interference pipe (hereinafter referred to as , a resonance silencing chamber, etc.) is characterized in that the resonance silencing chamber, etc. is provided in a hollow interior of a reinforcing frame attached to the back surface of the engine hood. Here, the "reinforcement frame" is for reinforcing the engine hood from the back side, and depending on the size of the engine hood and the method of reinforcement, the "reinforcement frame" may have a rectangular frame shape,
Cross-shaped, parallel-shaped, and other various shapes can be selected as appropriate. Further, the hollow interior of the reinforcing frame may be used as it is as a resonant silencing chamber or the like, or a separate hollow member may be inserted into the hollow interior of the reinforcing frame and the interior of the hollow member may be used as a resonant silencing chamber or the like.

[0006]

[Operation] According to the silencer configured as described above, the resonance silencing chamber etc. are provided in the hollow interior of the reinforcing frame attached to the back side of the engine hood, so many parts and piping are not required as in the conventional case. There is no need to provide a space for arranging a resonant silencing chamber or the like near the intake pipe where the air is crowded, so the space in the engine room is not narrowed.

[0007]

[Embodiment] A first embodiment in which the present invention is embodied in a resonance type muffling device installed in an intake pipe of an internal combustion engine of an automobile.
This will be explained with reference to FIGS. 1 to 3. In the engine room 12 of the automobile 11, the air cleaner 1 of the internal combustion engine 13 is installed.
A communication pipe 5 whose lower end communicates with the air hose 3 and whose upper end is open is provided in the middle of the air hose 3 as an intake pipe connecting between the fuel injection device 2 and the fuel injection device 2 .

[0008] Further, on the back side of the engine hood 14 that covers the engine compartment 12 in an openable and closable manner, the engine hood 1
A reinforcing frame 15 for reinforcing 4 is attached. This reinforcing frame 15 consists of a flange portion 16 fixed to the engine hood 14 and a hollow rib portion 17 protruding from the flange portion 16 toward the engine room 12, and is manufactured by, for example, sheet metal press molding or synthetic resin molding. You can use the one provided. The rib portion 17 of this embodiment is composed of a rectangular frame portion 17a on the outer periphery and two intersecting portions 17b extending over the square frame portion 17a, but this configuration may be modified as appropriate. The hollow interior formed between the inner surface of the rib portion 17 and the lower surface of the engine hood 14 directly constitutes the resonance muffling chamber 4.

In FIG. 1, a communication hole 6 for opening the resonance muffling chamber 4 is formed on the lower surface of the intersection 17 on the right side, and a soft packing 7 is attached around the communication hole 6. When the engine hood 14 is closed, the packing 7 comes into airtight contact with the upper end of the communication pipe 5, so that the communication hole 6 of the resonance muffling chamber 4 communicates with the opening of the communication pipe 5. . The resonance frequency of the resonance silencing chamber 4, that is, the silencing frequency f0, is expressed by the following equation 1.

0010

[Math. 1] f0 = (C/2π)・√(S/(V・L))
Here, C = 331.5 + 0.61t: Speed of sound (
m/sec) S = πD2/4: Cross-sectional area of communication tube 5 D: Inner diameter of communication tube 5 V: Volume of resonance silencing chamber 4 L = L1 +0.8D L1: Length t of communication tube 5: Temperature (℃ )

In this embodiment, in order to set the silencing frequency f0 to, for example, 90 Hz at a temperature of 20° C., the communicating pipe 5 has D=5 cm, S=19.6 cm2, and L1=2.
It is formed into a 0 cm cylindrical shape. In addition, the resonance silencing chamber 4
A total of V=3000 cm3 is secured within the hollow interior of the reinforcing frame 15.

According to the silencing device of this embodiment constructed as described above, the resonant silencing chamber 4 is provided in the hollow interior of the reinforcing frame 15 attached to the back surface of the engine hood 14. There is no need to provide a space for arranging a resonance silencing chamber near the air hose 3 where many parts and pipes are crowded, and therefore the space in the engine room 12 is not narrowed.

Next, the second embodiment shown in FIGS. 4 and 5 is as follows.
A side branch resonance tube 9 made of synthetic resin or metal, which is connected to the air hose 3 at one end through the communication hole 6 and the communication pipe 5 and whose other end is closed, is bent into the hollow interior of the intersection 17b of the reinforcing frame 15. It differs from the first embodiment only in that it is inserted. Assuming that the length of this side branch resonance tube 9 is L2, its resonance frequency, that is, the silencing frequency f0 is expressed by the following equation 2.

[0014]

[Formula 2] f0 = (2n-1)C/4L2 where, n
=1,2,...

Now, at a temperature of 20°C, the silencing frequency f0
For example, to set 60Hz, L2 = 14
It has to be quite long, 3cm. However, according to the muffling device of this embodiment, the long side branch resonance tube 9 can be easily accommodated in the hollow interior of the reinforcing frame 15. This second embodiment also has the same effects as the first embodiment.

Next, the third embodiment shown in FIGS. 6 and 7 is as follows.
An interference tube 10 made of synthetic resin or metal and having both ends communicating with the air hose 3 through the communication hole 6 and the communication pipe 5 is bent and inserted into the hollow interior of the square frame portion 17a and the intersection portion 17b of the reinforcing frame 15. This embodiment differs from the first embodiment only in the following points. Let L3 be the effective length between both ends of this interference tube 10 (the length when the bend is extended), and the straight line distance between the openings at both ends of the interference tube 10, that is, the correspondence of the air hose 3 corresponding to the interference tube 10. If the length is L4, then L3-L
Since interference occurs at a frequency where 4 is a half wavelength, the frequency of this interference, that is, the silencing frequency f0, is expressed by the following equation 3.

[0017]

[Math 3] f0 = C/[2(L3-L4)]

00
18] Now, in order to set the silencing frequency f0 to 100 Hz, for example, L3-L4 must be 172 cm. Therefore, for example, if L4 = 40 cm, L3 must be extremely long, ie, 212 cm. However, according to the silencer of this embodiment, the long interference tube 10 can be easily accommodated in the hollow interior of the reinforcing frame 15. This third embodiment also has the same effects as the first embodiment.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, but can be modified and embodied as desired without departing from the spirit of the invention, for example as follows. (1) In the first embodiment, a separate hollow member is inserted into the hollow interior of the reinforcing frame 15, and the interior of the hollow member is used as the resonance muffling chamber 4. (2) In the second embodiment or the third embodiment, the reinforcing frame 15
The hollow inside of the tube can be used as it is as a side branch resonance tube 9 or an interference tube 10.

[0020]

[Effects of the Invention] Since the silencer for an internal combustion engine according to the present invention is configured as described above, it has the excellent effect of being able to be rationally installed in the engine room without narrowing the space. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an attached state of a resonance type muffler according to a first embodiment.

FIG. 2 is a sectional view of the same muffler.

FIG. 3 is a front view showing the installed state of the muffling device.

FIG. 4 is a sectional view of a side branch resonance type muffling device according to a second embodiment.

FIG. 5 is a partial perspective view showing the installed state of the muffling device.

FIG. 6 is a sectional view of an interference type muffling device according to a third embodiment.

FIG. 7 is a partial perspective view showing the installed state of the muffling device.

[Explanation of symbols]

3 Air hose as intake pipe line 4 Resonance silencing chamber 9 Side branch resonance pipe 1
0 Interference tube 13 Internal combustion engine
14 Engine hood 15 Reinforcement frame

Claims (1)

[Claims] 1. A silencer provided with a resonance silencing chamber, a side branch resonance tube, or an interference tube that communicates with an intake pipe of an internal combustion engine, wherein the resonance silencing chamber, side branch resonance tube, or interference tube communicates with an intake pipe of an engine hood. A silencer for an internal combustion engine, characterized in that it is provided in a hollow interior of a reinforcing frame attached to the back side.