JPH02241917A - Muffler for automobile - Google Patents

Abstract

PURPOSE:To dispose a long tail pipe section in a muffler body by providing a tail pipe section which is connected at one end to one of tail pipes and at the other end to the other one of the tail pipes and which constitutes a helical pipe passage extending from its one end to the other end. CONSTITUTION:Two tail pipes 13, 14 are supported by an end plate 15 and a partition plate 16. A long helical long pipe passage 18 is defined by a helical pipe passage forming plate 17 between the end plate 15 and the partition plate 16. Cut-out holes 13a, 14a which are formed in the tail pipes 13, 14, respectively, are opened to the pipe passage 18 so that the tail pipes 13, 14 are communicated with the pipe passage 18. Further, the tail pipe 14 is provided to thereto with a control valve 21 which closes the pipe passage when the engine rotational speed is low but opens the same when the engine rotational speed is high. With this arrangement, a long tail end pipe in an controlled type exhaust system can be disposed in the muffler body 11, thereby it is possible to overcome the restriction to the layout and to give an excellent aesthetical view.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control type automobile silencer that changes the tail pipe length depending on the engine rotational speed range.

(Prior Art) As such conventional automobile silencers, there are those shown in FIG. 5, FIG. 6, and FIG.
Utility Model Application No. 62-24007, Utility Model Application No. 62-6791
(See Publication No. 4, etc.)

In the conventional example shown in FIG. 5, the exhaust gas introduced from the inlet vibe 2 of the muffler main body 1 is
The sound is discharged to the outside from the tail pipe 6.7 through the first expansion chamber 3, second expansion chamber 4, and third expansion chamber 5, which are sound-muffling elements inside. Here, the selection of the tail pipe is performed by determining the high or low engine rotational speed using the control unit 7 and opening and closing the valve 9 using the actuator 8. That is, in a region where the engine rotation speed is low, exhaust gas is released only from the long tail pipe 7 to reduce the low frequency level. Furthermore, in a region where the engine speed is high, exhaust gas is also released from the short tail pipe 6 to prevent a rise in back pressure.

The conventional example shown in Figures 6 and 7 is used for a silencer for an air compressor, and the silencer itself! and a covering body 10, the air flowing in from the inlet port 1K of the covering body 10 is distributed in equal amounts to the line-symmetrical tail pipe portion 12, and these airs are made to flow in opposite directions and are reversed many times at various places. This effectively muffles the low frequency components of the noise generated by the air compressor, and also effectively removes oil mist during unloading.

(Problem to be Solved by the Invention) However, due to the characteristics of the silencing principle, such conventional silencers require a somewhat long tail pipe (approximately 0.9 m or more) to reduce the low frequency components of the exhaust sound. ), but the length of such a long tail pipe cannot be secured only within the silencer body, and the structure is such that it is routed outside the silencer body, which is subject to layout constraints. It doesn't necessarily look good either. Furthermore, the conventional examples shown in FIGS. 6 and 7 have a problem in that the structure is complicated and the tail tube cannot be made very long.

The present invention has been made in view of these conventional problems, and its purpose is to provide a muffler for automobiles in which a long tail pipe portion is housed within the muffler main body. There it is.

(Means for Solving the Problems) Therefore, the present invention provides a control type automobile silencer in which the tail pipe portion of the silencer is modified so that the silencer is long in the low engine rotational speed range and short in the high rotational speed range. Two tail pipes are arranged in the muffler body, and one end is connected to one tail pipe of the two tail pipes, the other end is connected to the other tail pipe, and one end is connected to the other end of the muffler body. A tail pipe section was provided that formed a spiral channel from one side to the other end.

(Function) In the low engine speed range, all exhaust gas is exhausted to the outside through the tail pipe passing through the spiral pipe.

At high engine speeds, part of the exhaust gas is passed through the spiral pipe and the rest is not passed through.

As a result, in the low rotational speed range of the engine, the entire amount of exhaust gas passes through the long tail pipe section, so that the low frequency components of the exhaust sound can be reduced.

Furthermore, in a region where the engine speed is high, a portion of the exhaust gas is discharged without passing through the spiral pipe, thereby preventing an increase in back pressure.

(Example) Hereinafter, the present invention will be explained based on the drawings. An embodiment of the present invention is shown in FIG. 1 and FIG. 2, which shows a cross section taken along line I-1.

First, the configuration will be explained. The two tail pipes 13 and 14 are attached to the end plate 1
5 and a partition plate 16. A long spiral conduit 18 is formed between the end plate 15 and the partition plate 16 by a one-line conduit forming plate 17.

Furthermore, a notch hole 13a is formed in the tail pipe 13, and a notch hole 14a is formed in the tail pipe 14 toward the pipe line 18.
4 and a spiral conduit 18 are communicated with each other. Furthermore, tail pipe I4
A control valve 21 is installed in which the conduit is closed when the engine speed is low and opened when the engine speed is high. Note that 19 is a first expansion chamber, 20 is a second expansion chamber, and 21 is a resonance chamber.

Next, the effect will be explained. When the engine speed is low, the exhaust gas introduced into the muffler main body l from the inlet pipe 2 passes through the first expansion chamber 19 and the second expansion chamber 20,
Since the control valve 21 is closed, the entire amount passes through the long spiral pipe 18, is led to the tail pipe 13, and is discharged to the outside.

This effectively reduces low frequency sounds in the exhaust sound.

When the engine speed is high, the control valve opens and exhaust gas is also released from the tail pipe 14. Therefore, an increase in back pressure can be prevented.

In automobile exhaust systems, there are
In order to reduce low-frequency muffled noise, it is essential to lower the resonances of nodes 2 to 5 of the exhaust system air column resonances. For this purpose, lengthening the tail pipe portion of the exhaust system is an extremely effective means, especially in the low rotational speed range of the engine.

According to the present invention, the tail pipe section, which conventionally required a long path and was routed outside the muffler main body, can be replaced by the muffler main body! The length can be ensured by the spiral conduit 18 formed inside. For example, if the cross section of the silencer body l is 300φ
Assuming that the cross section of the tail pipe equivalent to 40φ is formed by the spiral conduit 18, the distance between the end plate 15 and the partition plate 16 is 4.
Even if it is assumed that 0xm, a pipe length of 1 m or more can be easily secured.

Furthermore, since the end plate 15 and the partition wall plate 16 are arranged close to each other, the two tail tubes 13 are supported by these two plates. +4
This increases the mounting strength and provides sufficient reliability even when the control structure such as the control valve 21 is placed in the tail pipe.

Furthermore, the radiated sound generated by the vibration of the end plate 15 of the muffler main body 1, which could be a problem because it is conventionally constructed of a thin plate, is also sufficiently reduced.

Another embodiment of the present invention is shown in FIG. 3 and FIG. 4, which is a cross-sectional view taken along line 1--2.

In this embodiment, the spiral conduit 18 is connected to two thin plates 22 and 23.
It is molded using a press process.

According to this embodiment, in addition to the effects of the above-described embodiments, the spiral conduit 18 is formed by press working of the thin plate 22 corresponding to the end plate and the thin plate 23 corresponding to the partition wall plate, so productivity is improved. can be significantly improved.

(Effects of the Invention) Since the present invention is configured as described above, it produces the effects described below.

The long tail pipe of the controlled exhaust system can be housed in the muffler body, which is superior in terms of layout constraints and aesthetics.

In addition, the support rigidity of the tail tube increases, improving reliability.

Furthermore, generation of radiated sound due to vibration of the end plate of the muffler main body can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
3 is a sectional view showing another embodiment of the present invention, FIG. 4 is a sectional view taken along line 1--■ in FIG. 3, and FIG. 5 is a conventional example. 6 is a sectional view showing another conventional example, and FIG. 7 is a sectional view taken along line II[-[11 of FIG. 6. 1... Silencer body, 13.14... Tail pipe, 13a. 14a... Notch hole, 15... End plate, 16... Partition plate, 17... 1 line conduit formation plate, 18... Spiral conduit, 21... Control valve, 22 .23...-Thin plate. 3 other people I[-1 ■-1

Claims (1)

[Claims] (1) In a control type automobile silencer in which the tail pipe length of the muffler is changed to be long in the low engine speed range and short in the high speed range, two tail pipes are arranged in the muffler body, and the muffler One end communicates with one of the two tail tubes, the other end communicates with the other tail tube, and a spiral conduit is provided at the end of the vessel body from one end to the other end. A silencer for an automobile, characterized in that a tail pipe portion is provided.