JPH09177537A - Automotive exhaust muffler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a sound radiated from a tail tube by dividing a dead space room by a partition plate arranged between two end plates in a muffler in which a valve provided in the opening part of the dead space room opened into the atmosphere is opened/closed and a capacity room is changed from a resonance element to an expansion element. SOLUTION: A muffler 1 is composed of an expansion room 3 to which a first tail tube 8 provided in the middle way of a sound intake chamber 9, a dead space room 2 and a capacity room 4. The inside of this dead space room 2 is divided by a partition plate 11 so as to form a second dead space room 12, this and the capacity room 4 are connected to each other by an opening part 13 and a valve 14 for closing the opening part 13 at the time of engine stop is provided. This valve 14 is opened when an exhaust gas flow rate is increased and pressure in the capacity room 4 reaches set pressure and thus, the capacity room 4 is opened into the atmosphere via the second dead space room 12 and a second tail tube 15 having the sound intake chamber 9 provided in the middle way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle exhaust muffler for reducing noise emitted from an exhaust system of an automobile or the like.

[0002]

2. Description of the Related Art As conventional exhaust muffler for automobiles,
For example, there is Japanese Patent Application No. 6-111111 as shown in FIG. This is an opening 113 provided in the end plate 106 in the muffler 101 for the purpose of both reducing exhaust noise at low rotation speed and reducing exhaust noise at high rotation speed and reducing exhaust loss.
The valve 114 for opening and closing is opened and closed by the pressure of the exhaust gas.

[0003]

However, in such a conventional vehicle exhaust silencer, the resonance frequency of the resonance element constituted by the dead space chamber and the tail tube and the neck tube and the volume chamber are set. When the resonance frequencies are close to each other, the pressure inside the volume chamber becomes very large near the resonance frequency, so that the end plate separating the dead space chamber and the volume chamber is vibrated with a large pressure. For this reason, the vibration level of the end plate increases, and as a result, the volume change of the dead space chamber increases, the resonance system composed of the dead space chamber and the tail tube is amplified to a greater extent and opened to the atmosphere. There was a problem that the emitted sound was emitted from the tail tube.

On the contrary, since the pressure in the expansion chamber becomes small due to the resonance effect of the resonance element composed of the neck tube and the volume chamber, the end plate separating the dead space chamber and the expansion chamber is vibrated with a large pressure. The sound emitted from the tail tube due to the pressure in the expansion chamber is not a problem.

The present invention has been made in view of such conventional problems, and an object thereof is to provide an exhaust muffler for a vehicle capable of suppressing the radiated sound emitted from the second tail tube. .

[0006]

In order to solve the above-mentioned problems, the present invention discloses a dead space chamber open to the atmosphere through a tail tube and a valve for opening and closing an opening provided in the dead space chamber. In a vehicle exhaust muffler having a volume chamber that changes from a resonance element to an expansion element when the valve opens and closes, a dead space chamber includes an outer cylinder, two end plates, and two end plates. It is composed of a partition plate arranged in between. Further, the dead space chamber is constituted by a cover provided on the end plate forming the volume chamber.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, muffler 1
Is composed of an expansion chamber 3, a dead space chamber 2, and a volume chamber 4, which are partitioned by end plates 5 and 6. An inlet tube 7 for introducing exhaust gas from an engine (not shown) is opened in the expansion chamber 3 in the muffler 1. Further expansion room 3
A first tail tube 8 in which a sound absorbing chamber 9 is provided in the middle is connected to the exhaust gas in order to open the introduced exhaust gas to the atmosphere. The volume chamber 4 is connected to the expansion chamber 3 via the neck pipe 10.

The dead space chamber 2 is partitioned by a partition plate 11 to form a second dead space chamber 12.

The second dead space chamber 12 and the volume chamber 4 are connected by an opening 13, and a valve 14 is provided so as to close the opening 13 when the engine is stopped. When the flow rate of exhaust gas increases and the pressure in the volume chamber 4 reaches the set pressure, the valve 14 opens, and the volume chamber 4 has a second dead space chamber 12 and a sound absorbing chamber 9 in the second tail. Since the structure is such that it communicates with the atmosphere via the tube 15, the volume chamber 4 acts as an expansion element.

Next, the function and effect of this embodiment will be described.

Since the volume of the second dead space chamber 12 is smaller than that of the dead space chamber 102 in the conventional example shown in FIG. 4, the second dead space chamber 12 is a spring and the tail tube is a mass of a resonance element. The resonance frequency is set higher than that of the conventional example. In the frequency band, the pressure in the volume chamber 4 is small, the vibration level of the end plate 6 separating the second dead space chamber 12 and the volume chamber 4 is small, and the volume change of the second dead space chamber 12 is also small. Become. Therefore, it is possible to suppress the radiated sound emitted from the second tail tube 15.

Further, in order to set the resonance frequency of the resonance element constituted by the second dead space chamber 12 and the second tail tube 15 to be high, the diameter of the tail tube acting as a mass is increased and the length of the tail tube is shortened. However, all of them impair the discharge noise when the valve 14 is opened, and thus are not feasible.

[Second Embodiment] FIG. 2 is a diagram showing a second embodiment of the present invention.

In FIG. 2, the dead space chamber 2 is constituted by a cover 16 provided on the end plate 6 forming the volume chamber 3, and the cover 16 is provided inside the expansion chamber 3.

With such a structure, the volume in the expansion chamber 3 can be increased as compared with the first embodiment, the sound deadening characteristic due to the expansion effect can be improved, and the first tail tube 8 can be provided. Therefore, it is possible to reduce the exhaust noise emitted from the second tail tube 15.

[Third Embodiment] FIG. 3 is a view showing a third embodiment of the present invention.

In FIG. 3, the dead space chamber 2 is composed of a cover 16 provided on the end plate 6 forming the volume chamber 4, and the cover 16 is provided in the volume chamber 4.

With such a structure, the volume in the volume chamber 4 can be increased as compared with the first embodiment, and the resonance frequency of the resonance element constituted by the neck 10 and the volume chamber 4 can be increased. It is possible to set the pressure lower and to separate from the resonance frequency of the resonance system formed by the dead space chamber 2 and the second tail tube 15, so that the pressure in the volume chamber 4 causing the volume change of the dead space chamber 2 is small. Becomes
The radiated sound generated from the second tail tube 15 can be suppressed to a low level.

[0020]

As described above, according to the present invention, the dead space chamber is constituted by the outer cylinder, the two end plates, and the partition plate arranged between the two end plates. Since the structure is configured by, it is possible to suppress the radiated sound emitted from the second tail tube.

Further, since the dead space chamber is constituted by the cover provided on the end plate forming the volume chamber and the cover is provided in the expansion chamber, the expansion chamber capacity is increased and the silencing characteristic due to the expansion action is improved. It is possible to reduce the exhaust noise emitted from the first and second tail tubes, and further, the dead space chamber is composed of a cover provided on the end plate forming the volume chamber, and the cover is provided in the volume chamber. With this structure, it is possible to reduce the pressure in the volume chamber that causes a change in the volume of the dead space chamber, and to suppress the radiation sound generated from the second tail tube.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 1,101 Muffler 2,102 Dead space chamber 3,103 Expansion chamber 4,104 Volume chamber 5,105 End plate 6,106 End plate 7,107 Inlet tube 8,108 First tail tube 9,109 Sound absorption chamber 11 Partition plate 12 second dead space chamber 13,113 opening 14,114 valve 15,115 second tail tube 16 cover 110 neck pipe

Claims (2)

[Claims] 1. A dead space chamber that is open to the atmosphere through a tail tube, a valve that opens and closes an opening provided in the dead space chamber, and a resonance element to an expansion element that is opened and closed by the valve. In an automobile exhaust muffler having a variable volume chamber, the dead space chamber is composed of an outer cylinder, two end plates, and a partition plate arranged between the two end plates. Exhaust muffler for automobiles. 2. A dead space chamber that is open to the atmosphere through a tail tube, a valve that opens and closes an opening provided in the dead space chamber, and a resonance element to an expansion element that is opened and closed by the valve. An exhaust muffler for an automobile having a variable volume chamber, wherein the dead space chamber is constituted by a cover provided on an end plate forming the volume chamber.