JPH08189331A - Muffler for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] An object of the present invention is to provide a low-cost muffler with a small number of parts that can change the sound deadening characteristics according to the opening / closing of the opening / closing valve. A first chamber 1 in which an exhaust introduction pipe 4 is opened, a third chamber 3 in which an exhaust outlet pipe 5 is opened, a second chamber 2 separated from the first chamber 1 and the third chamber 3, In a muffler including an inner pipe 6 that connects the first chamber 1 and the third chamber 3, an inner valve 6 is provided with an opening / closing valve 7 that opens and closes in an engine operating state, and the inner pipe 6 has upstream and downstream sides of the opening and closing valve 7. To the second
Communication holes 6a and 6b communicating with the chamber 2 are provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a muffler for an internal combustion engine, and more particularly to a muffler for an automobile internal combustion engine.

[0002]

2. Description of the Related Art As shown in FIG. 4, a first chamber in which an exhaust introduction pipe is open, a third chamber in which an exhaust discharge pipe is open, and a second chamber arranged between the first and third chambers. A chamber and an inner pipe that communicates the first chamber and the third chamber are provided, and the first chamber and the second chamber are communicated with the second chamber and the third chamber by relatively thin inner pipes. A muffler is known in which an on-off valve that opens and closes in an engine operating state is provided, and a muffling characteristic is changed according to opening and closing of the on-off valve. (See Japanese Utility Model Laid-Open No. 04-95609)

[0003]

However, in the apparatus of the above publication, since the first chamber and the second chamber and the first chamber and the third chamber are communicated with each other by relatively thin inner pipes, the number of parts is small. There was a problem that the cost was high in many cases. In view of the above problems, it is an object of the present invention to provide a low cost muffler that has a small number of parts and that can change the muffling characteristics depending on whether the on-off valve is opened or closed.

[0004]

According to the first aspect of the present invention, the first chamber in which the exhaust introduction pipe is opened, the third chamber in which the exhaust discharge pipe is opened, and the first chamber and the third chamber In a muffler for an internal combustion engine including a second chamber arranged between and a first chamber and an inner pipe that communicates with the third chamber, an inner valve is provided with an opening / closing valve that opens and closes in an engine operating state,
There is provided a muffler for an internal combustion engine, characterized in that communication holes communicating with the second chamber are provided on the upstream side and the downstream side of the opening / closing valve of the inner pipe. According to a second aspect of the present invention, there is provided the muffler for an internal combustion engine according to the first aspect, wherein the exhaust introduction pipe is further provided with a communication hole that communicates with the second chamber.

[0005]

According to the first aspect of the present invention, when the on-off valve is closed, the exhaust gas introduced through the exhaust introduction pipe expands in the first chamber and enters the second chamber through the communication hole on the upstream side of the inner pipe. After expanding in the second chamber, it enters the inner pipe through the communication hole on the downstream side of the inner pipe and passes through the inner pipe to the third chamber 3
And expands in the third chamber and exits from the exhaust outlet pipe. Also, when the on-off valve is open, after expanding in the first chamber, it passes through the inner pipe to enter the third chamber, expands in the third chamber, and exits from the exhaust outlet pipe, but the second chamber opens the inner pipe. It acts as a resonance chamber for the flow therethrough.

According to the second aspect of the present invention, when the on-off valve is closed, the exhaust gas introduced through the exhaust introduction pipe enters the second chamber through the communication hole of the exhaust introduction pipe and is expanded in the second chamber. ,
Although it enters the inner pipe through the communication hole of the inner pipe on the downstream side of the on-off valve, enters the third chamber through the inner pipe, expands in the third chamber and exits from the exhaust outlet pipe, but the first chamber is It acts as a resonance chamber for the flow entering the second chamber from the communication hole of the exhaust gas introducing pipe. Also, when the on-off valve is open, after expanding in the first chamber, it passes through the inner pipe to enter the third chamber, expands in the third chamber, and exits from the exhaust outlet pipe. Acts as a resonance chamber for the flow through.

[0007]

1 (A) and 1 (B) are views for explaining the structure and operation of a first embodiment of a muffler according to the present invention.
In FIG. 1A, 1 is a first chamber, 2 is a second chamber, and 3 is a third chamber. Reference numeral 4 denotes an exhaust introduction pipe, the upstream end of which is connected to an exhaust port of the engine through an exhaust pipe and an exhaust manifold (not shown), and the downstream end is open to the first chamber 1. Reference numeral 5 is an exhaust outlet pipe, and the upstream end is the third
It is open to the chamber 3 and the downstream end is open to the atmosphere.
An inner pipe 6 has an upstream end open to the first chamber 1 and a downstream end open to the third chamber 3, and an opening / closing valve 7 is arranged substantially in the center. . Further, communication holes 6a and 6b communicating with the second chamber 2 are provided on the upstream side and the downstream side of the opening / closing valve 7 of the inner pipe 6, respectively. In the conventional technique shown in FIG. The first communication pipe 8 and the second communication pipe 9 communicating the second chamber 2, the second chamber 2 and the third chamber 3 are deleted, and the number of parts is reduced accordingly, and the first communication pipe 8, Since the man-hours for welding the two communicating pipes 9 to the partition wall are unnecessary, the cost is low. The on-off valve 7 may be connected to the shaft via a spring so as to be opened by the exhaust gas pressure, or a load by an actuator,
Alternatively, it may be opened and closed depending on the number of rotations and the like.

As shown in FIG. 1A, when the on-off valve 7 is closed, the exhaust gas that has entered the first chamber 1 from the exhaust introduction pipe 4 is expanded in the first chamber 1, Inner pipe 6
The second pipe 2 enters the second chamber 2 through the communication hole 6a on the upstream side thereof and expands, and then the inner pipe 6 again through the communication hole 6b on the downstream side.
After entering the chamber, it reaches the third chamber 3, is expanded in the third chamber 3, and then is discharged to the atmosphere through the exhaust outlet pipe 5 to undergo three-stage expansion.

As shown in FIG. 1B, when the opening / closing valve 7 is open, the main flow of the exhaust gas entering the first chamber 1 from the exhaust introduction pipe 4 is expanded in the first chamber 1. After that, after reaching the third chamber 3 through the inner pipe 6 and expanding in the third chamber 3,
Although it is released into the atmosphere through the exhaust gas outlet pipe 5, the second chamber 2 is separated from the first chamber 1 to the third chamber 3 by the upstream communication hole 6a and the downstream communication hole 6b of the inner pipe 6. Since it acts as a resonance chamber for the flow through the inner pipe 6,
Two-step expansion + resonance is performed.

As described above, according to the first embodiment of the present invention, the on-off valve 7 is provided although the cost is low as compared with the prior art.
By opening and closing, it is possible to obtain two types of silencing characteristics as in the conventional technique.

FIGS. 2A and 2B are views for explaining the structure and operation of the second embodiment of the muffler according to the present invention. Compared with the first embodiment, the exhaust introduction pipe 4 is provided with a second Room 2
A communication hole 4a communicating with is added. Figure 2 (A)
When the on-off valve 7 is closed as shown in FIG. 2, the main flow of the exhaust gas enters the second chamber 2 through the communication hole 4a of the exhaust introduction pipe 4 and expands, and the exhaust gas flows from the second chamber 2 to the downstream of the inner pipe 6. It enters the inner pipe 6 through the side communication hole 6b, reaches the third chamber 3, is expanded in the third chamber 3, and then is discharged to the atmosphere through the exhaust outlet pipe 5, while the first chamber 1 is exhausted. Second from the introduction pipe
It acts as a resonance chamber for the flow entering the chamber 2, and two-stage expansion + resonance is performed.

When the on-off valve 7 is open as shown in FIG. 2B, the exhaust gas entering the first chamber 1 from the exhaust introduction pipe 4 is discharged as in the case of FIG. 1B. The mainstream expands in the first chamber 1, then reaches the third chamber 3 through the inner pipe 6,
After expanding in the third chamber 3, it is released into the atmosphere through the exhaust gas outlet pipe 5, and during this time, the second chamber 2 acts as a resonance chamber for the flow through the inner pipe 6, and two-stage expansion + resonance is performed.

As described above, in the second embodiment, as compared with the first embodiment, the exhaust introduction pipe 4 communicates with the second chamber 2 through the communication hole 4.
By adding a, two types of muffling characteristics different from those in the first embodiment can be obtained.

FIGS. 3A and 3B are views for explaining the structure and operation of the third embodiment of the muffler according to the present invention. The third embodiment is a modification of the second embodiment. However, compared with the second embodiment, the upstream side communication hole 6a of the inner pipe 6 is not provided, and accordingly, the number of processing steps is reduced and the cost is low.
However, the operation of the third embodiment is similar to that of the second embodiment, and when the on-off valve 7 is closed as shown in FIG. 3A, the main flow of exhaust gas is the exhaust introduction pipe. 4 enters the second chamber 2 through the communication hole 4a and expands from the second chamber 2 through the downstream communication hole 6b of the inner pipe 6 to the inner pipe 6
It enters into the third chamber 3 and is expanded in the third chamber 3 and then discharged to the atmosphere through the exhaust lead-out pipe 5. During this time, the first chamber 1
Acts as a resonance chamber for the flow entering the second chamber 2 from the exhaust introduction pipe, and a two-stage expansion + resonance effect is performed.
As shown in FIG. 3 (B), when the on-off valve 7 is open, the main flow of the exhaust gas entering the first chamber 1 from the exhaust introduction pipe 4 is expanded in the first chamber 1 After reaching the third chamber 3 through the pipe 6 and expanding in the third chamber 3, the second chamber 2 is released into the atmosphere through the exhaust lead-out pipe 5, and the second chamber 2 is
It acts as a resonance chamber for the flow through and two-stage expansion + resonance is performed.

As described above, in comparison with the second embodiment, the third embodiment does not have the upstream side communication hole 8 of the inner pipe 6,
As a result, it is possible to obtain the same silencing effect as that of the second embodiment, although the number of processing steps is reduced and the cost is low.

4 (A) and 4 (B) are views for explaining the structure and operation of the conventional muffler, which are different from those of the embodiment of the present invention shown in FIGS. The communication holes 6a and 6b and the communication hole 4a of the exhaust gas introducing pipe 4 are not provided, while the first chamber 1 and the second chamber 2, and the second chamber 2 and the third chamber 3 are thinner than the inner pipe 6, respectively. Communication pipe 8, second
A communication pipe 9 is used for communication.

As shown in FIG. 4A, when the opening / closing valve 7 is closed, the flow of the inner pipe 6 is blocked, so that the exhaust gas entering the first chamber 1 from the exhaust introduction pipe 4 is blocked. The gas expands in the first chamber 1, then enters the second chamber 2 through the first communication pipe 8 and expands in the second chamber 2, and then enters the third chamber 3 through the second communication pipe 9. After being expanded, the gas is discharged into the atmosphere through the exhaust outlet pipe 5 and expanded in three stages. As shown in FIG. 4B, when the opening / closing valve 7 is open, the main flow of the exhaust gas entering the first chamber 1 from the exhaust introduction pipe 4 is expanded in the first chamber 1 and then the inner chamber 1 is expanded. After reaching the third chamber 3 through the pipe 6 and expanding in the third chamber 3, it is released into the atmosphere through the exhaust lead-out pipe 5, during which the second chamber 2 is replaced by the first chamber 1.
And it acts as a resonance chamber for the expanding flow in the third chamber 3, and two-stage expansion + resonance is performed.

[0018]

According to the present invention, as in the prior art, 2
It is possible to obtain a muffler having various types of muffling effect with a smaller number of parts and a smaller welding man-hour as compared with the conventional technology.

[Brief description of drawings]

FIG. 1 is a view showing a structure of a first embodiment of a muffler according to the present invention, in which (A) shows a case where an on-off valve is in a closed state,
(B) shows the case where the on-off valve is open.

FIG. 2 is a diagram showing the structure of a second embodiment of the muffler according to the present invention, in which (A) shows the case where the on-off valve is in the closed state,
(B) shows the case where the on-off valve is open.

FIG. 3 is a diagram showing the structure of a third embodiment of the muffler according to the present invention, in which (A) shows the case where the on-off valve is in the closed state,
(B) shows the case where the on-off valve is open.

FIG. 4 is a diagram showing a structure of a conventional muffler,
(A) shows the case where the on-off valve is in the closed state, and (B) shows the case where the on-off valve is in the open state.

[Explanation of Codes] 1 ... First chamber 2 ... Second chamber 3 ... Third chamber 4 ... Exhaust introducing pipe 4a ... Communication hole 5 ... Exhaust outlet pipe 6 ... Inner pipe 6a ... Communication hole 6b ... Communication hole 7 ... Open / close valve 8 ... 1st communicating pipe (prior art) 9 ... 2nd communicating pipe (prior art)

Claims (2)

[Claims] 1. A first chamber in which an exhaust introduction pipe opens, a third chamber in which an exhaust discharge pipe opens, a second chamber arranged between the first chamber and the third chamber, and the first chamber. In an internal combustion engine muffler comprising an inner pipe communicating between the inner pipe and the third chamber, an opening / closing valve for opening / closing the inner pipe in an engine operating state is provided, and the inner pipe is provided on an upstream side and a downstream side of the opening / closing valve. A muffler for an internal combustion engine having a communication hole communicating with the second chamber. 2. The muffler for an internal combustion engine according to claim 1, further comprising a communication hole provided in the exhaust introduction pipe, the communication hole communicating with the second chamber.