JPH04276170A - Muffler device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the rise of temperature of an engine hood by securing the space for arrangement of a muffler device in an engine room and cutting of the heat supplied from the internal combustion engine. CONSTITUTION:As for a muffler device having a resonance type muffler chamber 4 communicating to the intake pipe line 3 of an internal combustion engine 13, side branch resonator pipe or an interference pipe, each of the resonance type muffler 4, side branch resonator pipe, or interference pipe is formed to an eccentric flat outer shape as a whole, and arranged on the reverse surface of an engine hood 14. Further, it is desirable to set each heat insulating member inside the resonation type muffler chamber 4, side branch resonator pipe or interference pipe.

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,
Resonant type muffling device with a box-shaped resonant muffling chamber that communicates with the intake pipe through a communication hole; ■ Side branch resonance muffler with a side branch resonant 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.

An object of the present invention is to solve the above-mentioned problems, to make it easier to secure a space for installing a silencer in the engine room, and to prevent the temperature of the engine hood from rising by blocking heat from the internal combustion engine. It is an object of the present invention to provide a silencing device that can also be used.

[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 resonant silencing chamber, etc.) is characterized in that the resonant silencing chamber, etc. is formed to have a flat outer shape as a whole and is disposed on the back surface of the engine hood. Further, it is preferable that a heat insulating material be placed inside the resonance muffling chamber or the like.

[0006]

[Operation] According to the silencer configured as described above, the resonant silencing chamber, etc., which is formed to have an overall flat outer shape, is arranged on the back side of the engine hood. There is no need to provide a space for installing a resonance muffling chamber or the like near the intake pipe where parts and piping are crowded. In addition, this flat resonance muffling chamber is located between the internal combustion engine and the engine hood, and since the interior thereof is mostly air with low thermal conductivity, it prevents heat radiation or convection from the internal combustion engine to the engine hood. shuts off and prevents the temperature of the engine hood from rising. Therefore, there is no need to dispose a heat insulating sheet or the like on the back surface of the engine hood as in the conventional case; in other words, a resonance muffling chamber or the like may be disposed in place of the conventional heat insulating sheet or the like. Furthermore, if a heat insulating material is placed inside the resonance muffling chamber or the like, the heat insulating effect will be further enhanced.

[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 . Also, an engine hood 14 that covers the engine room 12 in an openable and closable manner.
A resonant silencing chamber 4 made of heat-resistant synthetic resin or metal is disposed on the back surface of the resonant silencing chamber 4 so as to have a flat outer shape as a whole, and is attached with bolts or the like (not shown). A communication hole 6 is formed in the lower surface of the resonance muffling chamber 4, 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 silencing chamber 4 communicates with the opening of the communication pipe 5, and the resonance silencing chamber 4 communicates with the opening of the communication pipe 5. The chamber 4 is located directly above the internal combustion engine 13. The resonance frequency of the resonance silencing chamber 4, that is, the silencing frequency f0, is expressed by the following equation 1.

[0008]

[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 a diameter of 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
is formed in the shape of a flat rectangular parallelepiped container with an inner width of 30 cm, a width of 50 cm, and a height of 2 cm, and V = 3000.
cm3 is secured. Further, glass wool 8 as a heat insulating material is placed inside the resonance muffling chamber 4.

According to the silencing device of this embodiment constructed as described above, the resonant silencing chamber 4, which is formed to have an overall flat outer shape, is disposed on the back surface of the engine hood 14. There is no need to provide a space for arranging a resonant silencing chamber near the air hose 3 where many parts and piping are crowded as in the past. Moreover, this flat resonant silencing chamber 4 is
It is located between the internal combustion engine 13 and the engine hood 14, and the interior is mostly air with low thermal conductivity.
Radiation or convection of heat from the internal combustion engine 13 to the engine hood 14 is blocked to prevent the temperature of the engine hood 14 from rising. Furthermore, in this embodiment, glass wool 8 is placed inside the resonance muffling chamber 4, so that the heat insulation effect is further enhanced. Therefore, a heat insulating sheet or the like disposed on the back surface of the engine hood 14 as in the past becomes unnecessary.

Next, the second embodiment shown in FIGS. 4 and 5 is as follows.
By partitioning the inside of the flat rectangular parallelepiped container 15 in a spiral shape with the partition plate 16, the spiral side branch resonance tube 9, which is connected to the air hose 3 at one end and closed at the other end, has a flat outer shape as a whole. The second embodiment differs from the first embodiment only in that the side branch resonance pipe 9 is disposed on the back surface of the engine hood 14. If the length of this side branch resonance tube 9 is L2, then
The resonant frequency, that is, the silencing frequency f0, is given by the following equation 2
It is indicated by.

0012

[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 side branch resonance tube 9 is bent in a spiral shape and gathered into a flat shape, so that the side branch resonance tube 9 is not bulky in the length direction. This third embodiment also has the same effects as the first embodiment.

Next, the third embodiment shown in FIGS. 6 and 7 is as follows.
By partitioning the inside of the flat rectangular parallelepiped container 15 in a meandering manner with a partition plate 16, a meandering interference pipe 10 whose both ends communicate with the air hose 3 is formed so as to have a flat outer shape as a whole. This embodiment differs from the first embodiment only in that the pipe 10 is disposed on the back side of the engine hood 14. The effective length between both ends of this interference tube 10 (the length when the meandering is extended) is L3, and the straight line distance between the openings at both ends of the interference tube 10, that is, the corresponding length of the air hose 3 corresponding to the interference tube 10. If the length is L4, then L3 −
Since interference occurs at a frequency where L4 is a half wavelength, the frequency of this interference, ie, the silencing frequency f0, is expressed by the following equation 3.

[0015]

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

00
16] 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, since the interference tube 10 is bent in a meandering manner and gathered up flatly, the interference tube 10 is not bulky in the length direction. 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.

[0018]

[Effects of the Invention] Since the silencer for an internal combustion engine according to the present invention is configured as described above, it is easy to secure a space for installing the silencer in the engine room, and the heat from the internal combustion engine is blocked. This has the excellent effect of preventing the temperature of the engine hood from rising.

[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 bottom view of a side branch resonance tube of the same muffler.

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

FIG. 7 is a bottom view of the interference tube of the same muffler.

[Explanation of symbols]

3 Air hose as intake pipe 4 Resonance muffling chamber 8 Glass wool as heat insulating material 9
Side branch resonance tube 10 interference tube
13 Internal combustion engine 14 Engine hood

Claims (2)

[Claims] 1. A silencer provided with a resonance silencing chamber, a side branch resonance tube, or an interference tube communicating with an intake pipe of an internal combustion engine, wherein the resonance silencing chamber, side branch resonance tube, or interference tube is flat as a whole. 1. A muffler for an internal combustion engine, characterized in that it is formed to have an external shape and is disposed on the back side of an engine hood. 2. The muffling device for an internal combustion engine according to claim 1, wherein a heat insulating material is placed inside the resonant muffling chamber, the side branch resonant pipe, or the interference pipe.