JPH0452850B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention [Field of Industrial Application] This invention relates to a muffler for an internal combustion engine for a vehicle.

[Conventional technology]

In the muffler of an internal combustion engine, not only the exhaust discharge sound but also the sound emitted from the muffler, that is, the radiated sound and transmitted sound are major factors. Conventionally, as a measure to reduce the transmitted sound of the radiated sound, the outer cylinder is usually constructed with two or three layers, or a sound insulating material such as asbestos or glass fiber mat is interposed between the layers.

[Problem that the invention seeks to solve]

However, upon closer analysis, we found that when installed in a car (generally installed along the underside of the car body), the muffler is installed near the interior of the vehicle, i.e., on the top of the muffler, or on the exhaust inlet pipe or exhaust pipe. By selectively applying countermeasures to the outer cylinder wall surface that is close to the radiated sound and transmitted sound, it is possible to deal with radiated sound and transmitted sound.

The purpose of this invention is to extremely easily implement the above-mentioned selective measures.

B. Structure of the Invention [Means for Solving Problems] A cylindrical body is formed by winding thin plates in multiple layers, and a part of the circumferential surface of the cylindrical body is wound one more time than the other surface and fixed.

The area surface having many layers is positioned at the top when mounted on an actual vehicle, that is, facing the vehicle body.

Alternatively, place exhaust inlet pipes, exhaust pipes, etc. close to the range surface.

[Effect]

In a silencer cylinder made of multiple layers of thin plates, a sound deadening effect can be obtained by increasing the number of layers by one layer in the area where measures against radiated sound and transmitted sound are required.

〔Example〕

The thin steel plate 1 is wound around the core metal a necessary number of times, and at this time, the winding start side 1a and the winding end side 1b are tied together by the necessary circular arc range α, so that the range α is one more than the other ranges. I can do it.

Fig. 1 shows a cylinder with a circular cross section, and Fig. 2 shows a cylinder with an oval cross section, both of which are double-wound.
This is an example in which c is triplexed. Then, at least the winding end side 1b is fixed by spot welding W or the like.

The above cylinder is used as an outer cylinder, end plates 3, 3 are attached,
The exhaust gas introduction pipe 4, the discharge pipe 6, etc. are provided close to the cylindrical body circumferential surface 1c in the triple layered range α.

In the embodiment, a silencer is illustrated in which there is no partition plate in the interior of the cylinder, that is, there is only one exhaust expansion chamber, but the interior of the cylinder can be divided into multiple chambers with one or several partition plates. The chambers are divided into multi-stage expansion chambers or one of them acts as a resonance chamber.
In the case of a silencer that connects the chambers with each other through a connecting pipe, the connecting pipe is also connected to the exhaust inlet pipe 4 and the exhaust pipe 6.
Similarly, it is provided close to the circumferential surface 1c of the cylindrical body in the range α in which the cylindrical body is wound one more time.

In addition, when installed in a car 7 etc., the above range α
The silencer is configured to be installed with the circumferential side of the triple cylinder body facing the automobile, that is, facing upward.

C. Effect of the invention 1 In a silencer having an outer cylindrical body formed by winding thin plates, radiated sound and transmitted sound from the required area can be reduced by simply wrapping the peripheral surface in the required range one more layer than other surfaces. be able to.

Therefore, when installing the muffler in a car, etc., the muffler should be installed so that the surface of the cylindrical body with more than one layer faces toward the car body, thereby reducing the radiated and transmitted sound of the muffler that is received by the car body.

In addition, if the exhaust inlet pipe, exhaust pipe, or joint pipe attached to the silencer is placed close to the surface of the cylindrical body where many layers of windings are formed, it is possible to Since the noise emitted from the tube is reduced by the surface having one more layer, the radiated sound and transmitted sound emitted from the wind surface in front of the cylinder are reduced on average.

2. It uses less material than the conventional multi-layer structure, contributing to weight reduction and processing time.

3. Compared to a double cylindrical body with an air layer and a cylindrical body whose air layer is filled with sound absorbing material, it is superior in mass production and is constructed at a lower cost.

4. When mounting it on a car, etc., it should be installed so that the surface 1c, which has been wound one more time, is on top of the vehicle body 7 side, and the ends of the winding start side 1a and the winding end side 1b are facing downward. Therefore, exhaust gas condensed water and water that enters from the exhaust discharge pipe 6 during car washing do not enter between the winding layers through the gap at the end of the winding start side 1a by capillary action. Since the gap at the end of the winding end 1b faces downward, there is little intrusion of car wash water, rainwater, etc.

Therefore, when the muffler is rapidly heated, there is no risk of water entering between the winding layers being heated and deforming the inner surface.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the cylindrical body of the silencer of the present invention, and FIG. 3 is an explanatory diagram of the use state of the silencer. 1 is a thin plate, 1a is the winding start side, 1b is the winding end side, 1c is the circumferential surface of the cylinder with one layer between 1a and 1b, 4
is the exhaust inlet pipe, 6 is the exhaust pipe, and 7 is the vehicle body.

Claims (1)

[Claims] 1. In the outer cylinder of a silencer for a vehicle internal combustion engine, thin plates are wound in multiple layers to form a cylinder, and a part of the circumference of the cylinder is wrapped and fixed one more time than the other part, and that one more A silencer characterized by being installed with the surface of the layered area facing the vehicle body side, or having an exhaust inlet pipe, an exhaust pipe, etc. placed close to the surface of the cylindrical body where the layered layer is one layer. .