JPS58202321A - Discharge silencer of internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce a discharge noise and discharge pulsation and to decrease the output loss of an engine by filling an absorbing material layer between a casing and a cylindrical structure and by providing vibrating noise insulation plates at the expanded diameter portion of the cylindrical structure. CONSTITUTION:Exhaust gas discharged from an internal-combustion engine, etc. passes through a discharge pipe 2 and is introduced into a casing 1 through an exhaust gas guide port 4. The introduced exhaust gas hits the mass bodies 16 of vibrating noise insulation plates 14 and is guided to a cylindrical structure 6 side, passes through air holes 15a of thin plates 15, flows in succession downstream through a discharge passage 9, and is exhausted from an exhaust pipe 3 through an exhaust gas discharge port 5 into the atmosphere. The discharge passage 9 is formed straight from a discharge pipe 2 toward the exhaust pipe, and the vibrating noise insulation plates 14 are provided at a expanded diameter portion 7 with a wide flow cross section, and many air holes 15a are provided on the thin plate 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust silencing device for an internal combustion engine, which is capable of significantly reducing VC exhaust noise and exhaust pulsation, and which reduces engine output loss.

Conventional exhaust silencing methods include the following methods.

(a) Expansion method that expands the wave into the cavity, dilutes the acoustic energy density, and muffles the sound by squeezing it at the edge of the cavity.

(b) A resonance method in which a resonance cavity is differentially connected to the exhaust pipe through a communication hole, and the sound energy is completely consumed by resonance.

(c) A sound absorption method that absorbs sound by converting acoustic energy into thermal energy using an absorbing material.

(d) An interference method in which the sound tube is branched to give a path difference and the sound waves are split into limbs, and then merged again to attenuate sound 1& by sound interference.

Conventionally, these methods have been appropriately combined to muffle exhaust gas.

However, none of the conventional exhaust mufflers has a sufficient noise suppression effect, and those that have a certain degree of muffling effect do not divert or branch the exhaust flow.
Alternatively, the engine may have been throttled too much, obstructing the flow of exhaust gas and thus causing loss of power to the internal combustion engine.

The present invention has been devised to effectively solve the above-mentioned conventional problems, and an object of the present invention is to provide an internal combustion engine that can significantly reduce exhaust noise and exhaust pulsation, as well as reduce engine output loss. Engine exhaust? To provide a zero sound device.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In Fig. 1, 1 is a cylindrical casing, with an exhaust pipe 2 at one end and a discharge pipe 3 at the other end tangential to the central axis of the casing. An exhaust gas introduction port 4 is formed at the tip of the inserted exhaust pipe 2, and an exhaust gas discharge port 5 is provided on the side wall of the discharge pipe 3.

A bellows-shaped cylindrical structure 6 is provided inside the casing 1 along its axial direction, as shown in FIG.゛The cylindrical structure 6 has a V-shaped cross section with uneven waves, and the cylindrical structure 6 allows the inside of the casing 1 to
A linear exhaust flow path 9 is formed from the exhaust pipe 2 to the discharge pipe 3, in which enlarged diameter portions 1 and reduced diameter portions 8 are alternately repeated.

Further, a sound absorbing material layer 1o filled with a sound absorbing material is formed between the cylindrical structure 6 and the casing 1. The sound-absorbing material layer 10 consists of a heat-insulating sound-absorbing material 11 such as glass wool or asbestos arranged on the inner wall surface of the casing 1, and a lathe material filled with the inner cylindrical structure 6 side, which has a rougher gap than glass wool or the like. It is made of two unique sound-absorbing materials: 12 absorbers made of waste, etc.

Further, the cylindrical structure 6 is provided with a large number of ventilation holes 13,
These ventilation holes 13 allow open sound waves between the sound absorbing material layer 10 and the exhaust flow path 9 in the cylindrical structure 6 to freely pass through.

A vibration sound insulating plate 14 is provided in the enlarged diameter portion 7 of the exhaust flow path 9 so as to intersect and block the exhaust flow path 9t/c@ so that sound waves do not pass through. Vibration sound insulation@, 14 is the third
As shown in the figure, a thin plate 1 has a large number of ventilation holes 15a in its distal portion, and its peripheral portion is fixed to a cylindrical structure 6 by welding or the like.
5, and a disk-shaped relatively thick mass body 16 attached to the center of the thin plate 15. Since the thin plate 15 has a ventilation hole 15a and is made of a highly elastic metal, the thin plate 15 functions as a spring that allows the mass body 16 to vibrate in the uniaxial direction of the casing.

Next, the operation of this embodiment will be described.

Exhaust gas discharged from an internal combustion engine or the like passes through an exhaust pipe 2 and is introduced into the casing 1 from an exhaust introduction port 4. The introduced exhaust gas is guided to the HF body 16 of the vibration sound insulating plate 14, guided to the cylindrical structure 6 side, passes through the ventilation hole 15m of the thin plate 15,
The exhaust flow M9 sequentially flows to the downstream side, and then the exhaust flow M9 flows to the exhaust outlet 5.
It is then discharged into the atmosphere from the discharge pipe 3. In the silencer of the present invention, the exhaust flow path 9 is formed straight from the exhaust pipe 2 to the discharge pipe 3, and the vibration sound insulating plate 14 is provided in the enlarged diameter portion 7 with a wide cross section of the flow path. Stomata 1
Since a large number of noise suppressors 5a are also provided, the exhaust gas flows smoothly through the exhaust flow path 9, and therefore, the output loss of the internal combustion engine due to this muffler is extremely small.

On the other hand, the sound waves (
Exhaust noise) is silenced as follows.

The thin plate 15 of the vibration sound insulation board 14 acts as a spring that elastically supports the mass body 16, so when the sound waves (and pulsations associated with exhaust air) hit the vibration sound insulation board 14, the mass body 16 moves in the Goo/Fugu 1-axis direction. Vibration is applied, and the acoustic (and pulsating) energy is absorbed as vibration energy of the vibration sound insulating plate 14. Further, since the cylindrical structure 6 has a large number of ventilation holes 13 and is formed in a V-shaped uneven wave shape in cross section, the sound wave
is repeatedly reflected by the similar structure 6, the casing 1, and the vibration sound insulating plate 14, as shown in FIG. It is absorbed as thermal energy by the materials 11 and 12.

Furthermore, since the ventilation hole 13 of the cylindrical structure 6 is a neck part, the sound absorbing material layer 10 acts as a resonant cavity (spring), and the energy of the sound wave is consumed by resonance. #While the L road 9V is being transmitted, the vibration sound insulating plate 14
The pressure vibration of the sound wave is suppressed by repeating the expansion and contraction process in which the air is narrowed through the air vent 15a and expanded from the air hole tSa to the exhaust air tN between the vibration sound insulating plate 14 and the path 9.

In addition, in the above embodiment, the vibration sound insulating plate 14 is replaced by the thin plate 1.
5 and a mass body 16, but instead of the thin plate 14, the mass body 16 is elastically supported from the node-like structure Δ body 6 by using a rod-shaped material having elasticity, a powder material, or a leaf spring. You may also do so. Of course, the vibration and sound insulating plates 14 in the housing may be of an integral structure, and it is also possible to provide the vibration and sound insulating plates 14 every other time in the enlarged diameter portion 1 of the exhaust flow path 9.

As is clear from the above explanation, according to the present invention, the exhaust noise and exhaust pulsation of an internal combustion engine can be significantly reduced, and the output loss of the internal combustion engine can be reduced without impeding the exhaust flow. Furthermore, it has a simple structure, can be manufactured easily, and can exhibit excellent effects such as being rich in usefulness VC.

FIG. 1 is a longitudinal sectional view showing an embodiment of the device according to the present invention;
FIG. 2 is an enlarged sectional view of the same portion, and FIG. 3 is a front view of the vibration and sound insulating plate shown in FIG. 1.

In the figure, 1 is the casing, 2 is the exhaust pipe, 3 is the discharge pipe, 4 is the exhaust inlet, 5 is the exhaust outlet, 6 is the cylindrical structure, I is the enlarged diameter part, 8 is the reduced diameter part, and 9 is the Exhaust flow path, 10 is a sound absorbing material layer, 1
1.12 is a sound absorbing material, 13 is a ventilation hole of the cylindrical structure, and 14 is a vibration sound insulating plate.

Patent applicant Makoto Minamidate (2 others) Agent Patent Attorney Nobuo Kinutani Figure 3

Claims (1)

[Claims] l In order to form an exhaust flow path, an exhaust inlet port is provided at one end of the exhaust flow path,
A front body-shaped casing having an exhaust outlet at the other end, and a bellows-shaped cylindrical structure provided within the casing to alternately form enlarged diameter portions and reduced diameter portions along the axial center of the casing. , a large number of ventilation holes provided in the planar structure, a sound absorbing material layer filled between the casing and the cylindrical structure, and the expanded diameter portion of the cylindrical structure. An exhaust muffling device for an internal combustion engine, comprising a vibration shielding plate that is provided so as to be able to freely vibrate across an exhaust flow path. 2 The above swing v! The IJ sound insulating plate is configured to have a ventilation hole in its distal part to impart elastic force, and also to have a quality part in its narrow part that intersects with the exhaust flow path vc@. Exhaust silencer for internal combustion engine as described in Section 1〇