JPH0810652Y2 - Exhaust silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an exhaust muffler for an automobile, and particularly to
The present invention relates to an exhaust silencer in which a silencer is arranged in parallel with an exhaust pipe line of a book.

[Conventional technology]

Recently, in an automobile exhaust muffler, in order to improve the muffling performance in a wide engine speed range, for example, as disclosed in Japanese Utility Model Publication No. 61-184810 and Japanese Utility Model Publication No. 63-79421, A system in which a control valve is provided in the exhaust pipe has been developed.

On the other hand, in order to reduce the exhaust resistance of the exhaust pipe, for example,
An exhaust silencer as shown in Fig. 4 has been developed.

In this exhaust silencer, the first and second exhaust pipe lines 1
1, 13 are formed in parallel. For example, in the case of a 6-cylinder engine, half the three cylinders are connected to the first exhaust pipe line 11, and the other three cylinders are connected to the second exhaust pipe line 13. It is in communication.

Then, the first exhaust pipe line 11 is provided with the first exhaust pipe 11 in order from the upstream side.
The catalytic converter 15, the first sub-muffler 17, and the first main muffler 19 are interposed in series.

A second catalytic converter 21, a second sub-muffler 23, and a second main muffler 25 are provided in series in the second exhaust pipe line 13 in this order from the upstream side.

In this example, the first and second sub-mufflers 17, 23
The so-called resonance type silencer is used in the
A so-called resonance expansion type silencer is used for the second main silencers 19 and 25.

In this example, the first exhaust pipe line 11 and the second exhaust pipe line 13 are communicated with each other by the communication pipe 27 upstream of the first sub-muffler 17 and the second sub-muffler 23. .

In the exhaust silencer configured as described above, the exhaust gas from one half of the cylinders of the engine flows into the first exhaust pipe line 11, and the exhaust gas from the other half cylinders flows into the second exhaust pipe line 13.
Since the gas flows into the exhaust gas, it is possible to reduce mutual interference of exhaust gas and reduce exhaust resistance.

Further, the first exhaust pipe line 11 and the second exhaust pipe line 13 are connected by a communication pipe 27, and further, the first and second sub-mufflers 17, 2 are connected.
Since the 3 is arranged, it is possible to effectively prevent the generation of so-called muffled noise in the low engine speed range.

[Problems to be solved by the device]

However, in such a conventional exhaust silencer,
Since the first and second exhaust pipe lines 11 and 13 are provided and the auxiliary silencers 17 and 23 and the main silencer 19 and 25 are arranged in the exhaust pipe lines 11 and 13, respectively, If the capacity is increased by 1, the capacity of the muffler is very difficult to increase because the capacity of the first and second exhaust pipe lines 11 and 13 is increased by 2. As a result, the engine rotation speed is low. There is a problem that it is very difficult to effectively reduce low-frequency noise in the region.

The present invention has been made in order to solve such a conventional problem, and provides an exhaust silencer capable of significantly reducing noise in a low engine speed range without increasing the capacity of the silencer. Is what you are trying to do.

[Means for solving the problem]

In the exhaust silencer according to the present invention, the first and second exhaust silencers are provided in parallel in the first and second exhaust pipelines, and the first and second exhaust pipelines are connected to each other. An exhaust muffler that is in communication with the upstream side of the first and second mufflers, the first muffler of the first exhaust pipe line.
The downstream side of the muffler, the outlet end of which is open to the atmosphere, is provided with a control valve which is closed when the engine rotates at low speed and is opened when the engine rotates at high speed.

[Action]

In the exhaust silencer of the present invention, when the control valve is closed when the engine is running at low speed, the so-called branch exhaust system is formed in the first exhaust pipe line, downstream of the communicating portion with the second exhaust pipe line. First to be located in this bulge exhaust system
The silencer makes the volume of the bulge exhaust system very large and effectively reduces noise in the low frequency range.

On the other hand, at high engine speed, the control valve is opened,
The first and second exhaust pipe lines effectively reduce noise in the high frequency range.

〔Example〕

Hereinafter, the details of the present invention will be described with reference to the embodiments shown in the drawings.

FIG. 1 shows an embodiment of the exhaust silencer of the present invention. In this exhaust silencer, first and second exhaust pipe lines 31, 33 are formed in parallel, for example, 6 cylinders. In the case of an engine, the first exhaust pipe line 31 is directly connected to half of the three cylinders, and the second exhaust pipe line 33 is directly connected to the other three cylinders.

Then, in the first exhaust pipe line 31, the first exhaust pipe line 31 is sequentially arranged from the upstream side.
The catalytic converter 35, the first sub-muffler 37, and the first main muffler 39 are installed in series.

A second catalytic converter 41, a second auxiliary silencer 43, and a second main silencer 45 are serially inserted in the second exhaust pipe line 33 in this order from the upstream side.

In this embodiment, the first and second sub-mufflers 3
The so-called resonance type silencer is used for 7,43,
So-called resonance expansion type silencers are used for the first and second main silencers 39, 45.

In this embodiment, the first exhaust pipe line 31 and the second exhaust pipe line 33 are connected to the first sub-muffler 37 and the second sub-muffler 43.
Is connected by a communication pipe 47 upstream of the.

Thus, in this embodiment, the first exhaust line 31
On the downstream side of the muffler 39, an outlet pipe 54 whose pipe end is open to the atmosphere is attached, and a control valve 49 is interposed in the outlet pipe 54.

In the figure, reference numeral 51 indicates a control device for opening and closing the control valve 49. This control device 51 inputs the engine speed, and, for example, the engine speed is 2500 to 3000 rp.
The control valve 49 is closed at a low rotation speed of about m or less, while the control valve 49 is opened at a high rotation speed of the engine exceeding 2500 to 3000 rpm.

That is, in the exhaust silencer configured as described above, the control valve 49 is closed when the engine is running at low speed, and the exhaust gas flowing from the engine into the first exhaust pipe line 31 is discharged from the first catalyst. After passing through the converter 35, it flows into the second exhaust pipe line 33 from the communication pipe 47, merges with the exhaust gas of the second exhaust pipe line 33, and then the second auxiliary silencer 43 and the main silencer 45.
It will be discharged to the outside through.

As a result, in the first exhaust pipe line 31, the downstream side of the communication part 53 to the second exhaust pipe line 33 becomes a so-called branch exhaust system, and the first sub-muffler is located in this branch exhaust system. 37 and the first main silencer 39 make the volume of the branch exhaust system very large and effectively reduce the noise in the low frequency range.

On the other hand, when the engine is rotating at high speed, the control valve 49 is opened, and the first and second exhaust pipe lines 31, 33 effectively reduce noise in the high frequency range.

Then, in the exhaust silencer configured as described above, the first silencer 39 of the first exhaust pipe line 31 is
Since the control valve 49, which is closed at low engine speed and opened at high engine speed, is installed in the outlet pipe 54 whose pipe end is open to the atmosphere, without increasing the capacity of the muffler, It is possible to significantly reduce the noise in the low rotation speed range of the conventional method.

That is, in the exhaust silencer configured as described above, the control valve 49 is closed when the engine is running at low speed, so that the first exhaust pipe line 31 communicates with the second exhaust pipe line 33. The downstream side of 53 becomes a so-called branch exhaust system, and the volume of the branch exhaust system becomes very large due to the first sub-muffler 37 and the first main muffler 39 which are located in this branch exhaust system. Therefore, as shown in FIG. 2, it is possible to significantly reduce noise in the low frequency range as compared with the conventional case.

In FIG. 2, the horizontal axis represents the engine speed and the vertical axis represents the exhaust noise amount. The solid line represents the case where the control valve 49 is open, and the broken line represents the control valve. Shows the case where is closed.

Therefore, in the above-described embodiment, the muffling characteristic is shown by the broken line in the low rotation range, while it is shown by the solid line in the high rotation range.

FIG. 3 shows another embodiment of the exhaust silencer of the present invention. In this embodiment, the engine has one exhaust pipe.
55 is connected and is branched to a first exhaust pipe line 59 and a second exhaust pipe line 61 on the downstream side of the catalytic converter 57.

The first and second exhaust pipe lines 59, 61 have the first
Further, the second main silencer 63, 65 is interposed, and an outlet pipe 78 whose pipe end is open to the atmosphere is attached to the downstream side of the main silencer 63 of the first exhaust pipe line 59. Further, a control valve 67 is interposed in the outlet pipe 78.

In the exhaust silencer configured as described above, when the control valve 67 is closed when the engine is running at low speed, the first exhaust pipe line 59 becomes a branch exhaust system. It is possible to obtain almost the same effect as the example.

[Effect of device]

As described above, in the exhaust silencer of the present invention, the exhaust pipe downstream of the first silencer of the first exhaust pipe line, the pipe end of which is open to the atmosphere, is connected to the outlet pipe at low engine speed. Since the control valve that is closed and opened at high rotation speed is interposed, there is an advantage that noise in the low rotation speed range of the engine can be significantly reduced compared to the conventional case without increasing the capacity of the silencer. .

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an embodiment of an exhaust silencer according to the present invention. FIG. 2 is a graph showing the muffling characteristics of the exhaust muffler of FIG. FIG. 3 is a piping system diagram showing another embodiment of the exhaust silencer of the invention. FIG. 4 is a piping system diagram showing a conventional exhaust silencer. [Explanation of symbols of main parts] 31 …… first exhaust pipe 33 …… second exhaust pipe 39 …… first main silencer 45 …… second main silencer 47 …… communication pipe 49 ... Control valve.

Claims (1)

[Scope of utility model registration request] 1. A first and a second silencer (39, 4) in a first and a second exhaust pipe lines (31, 33, 59, 61) arranged in parallel.
5, 63, 65) and the first and second exhaust pipe lines (31, 33, 59, 61) are connected to the first and second silencers (39, 45, 63, 65). The exhaust muffler that communicates with the upstream side of the first exhaust pipe line (31, 59).
A control valve that is closed at low engine speed and opened at high engine speed at the outlet pipe (54, 78) downstream of the silencer (39, 63) and whose pipe end is open to the atmosphere. An exhaust silencer characterized by having (49, 67) interposed.