JP2000257414A - Muffler for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of a muffler and its surrounding area due to high temperature as much as possible, while preventing lowering of noise reduction effect due to high-temperature exhaust gas. SOLUTION: This muffler comprises an engine side exhaust pipe 1 and a shell 2. The shell 2, at one end retains the exhaust pipe 1 to be inserted therein at one end and air inflow passages 6, 7 above and below or to the right and left to the exhaust pipe 1. The shell 2 also is provided with an exhaust gas jet opening at the other end. An inserted portion of the exhaust pipe 1 is covered with plates 3, 4 that form the air inflow passages 6, 7 extending over substantially the entire length of the shell 2 and two side plates 12, 13 perpendicular to the plates 3, 4, which are formed in a square shape. Around the exhaust pipe, four inner vent passages 15 are provided, which are defined by these plates the outer peripheral surface of the exhaust pipe 1. Two outer vent passages are provided between two side plates 12, 13 that form the inner vent passages 15 and the shell 2. Air vents 10, 11 are provided on both corners of the deepest part of the air inflow passages 6, 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a muffler for an internal combustion engine.
More specifically, a muffler that introduces air having a temperature lower than the exhaust gas temperature into the muffler to reduce the pressure and temperature of the exhaust gas so as to exhibit a silencing effect and improve exhaust efficiency during traveling. It is about.

[0002]

2. Description of the Related Art A conventional muffler for an internal combustion engine employs various types, such as sound absorption, expansion, resonance, interference, and resistance, alone or in combination. It is structurally complicated. In addition, a sound absorbing type is used as a sports muffler. In this case, the temperature of the exhaust gas becomes extremely high, so that the sound absorbing material is apt to be deteriorated. The bumper near the exit may burn.

[0003]

As described above, in the case of the conventional muffler, the muffler and its surroundings are liable to have a reduced sound-muffling effect due to the effect of high-temperature exhaust gas, and the muffler and its surroundings are easily damaged. Was desired. SUMMARY OF THE INVENTION The present invention has been made in order to meet such a demand, and provides a muffler for an internal combustion engine capable of preventing deterioration of a muffler effect due to high-temperature exhaust gas and suppressing high-temperature deterioration of a muffler and a peripheral portion thereof as much as possible. That is the task.

[0004]

According to the present invention, there is provided an engine-side exhaust pipe, and the exhaust pipe is inserted at one end of the exhaust pipe while holding an air inflow path at the top and bottom or left and right thereof, and exhaust gas is injected at the other end. A shell having an opening for use therein, wherein the insertion portion of the exhaust pipe in the shell is provided with two plates forming the air inflow passage extending substantially over the entire length of the shell, and two plates perpendicular to the plate.
Four side plates are formed in a square shape and cover these plates and the outer peripheral surface of the exhaust pipe to provide four inner ventilation paths around the exhaust pipe, and two side plates forming the inner ventilation paths. A muffler for an internal combustion engine, characterized in that two outer ventilation paths are provided between the air inlet and the shell, and ventilation ports are formed at both innermost corners of the air inflow path. Settled.

[0005]

Embodiments of the present invention will be described with reference to the accompanying drawings. First, a first embodiment shown in FIGS. 1 to 3 will be described. In the drawings, reference numeral 1 denotes an engine-side exhaust pipe having a circular cross-section, and a rear half or more of the exhaust pipe is provided inside a larger-diameter shell 2. It is stored in. An upper plate 3 closely contacted with the upper surface of the exhaust pipe 1 in line contact with the upper surface of the exhaust pipe 1 is provided at an upper part in the shell 2, and a lower part of the shell 2 in line contact with the lower surface of the exhaust pipe 1. A lower plate 4 in close contact is provided. The width of these plates 3, 4 is
The diameter is set to be larger than the diameter of the exhaust pipe 1.

On the front surface of the shell 2, that is, on the end face on the engine side, an upper air inlet channel 6 is left above the upper plate 3, and a lower air inlet channel 7 is located below the lower plate 4. A front end plate 5 that closes and blocks other parts is installed. On the other hand, a rear end plate 9 is attached to the rear surface of the shell 2, and a rear end exhaust pipe 8 described later is provided.
Closed leaving part.

Both corners of the rear end of the upper plate 3 are cut off to form ventilation holes 10 and 10 downward.
Further, both corners of the rear plate side end of the lower plate 4 are cut off to form upward ventilation ports 11 and 11. These vents 10 and 11 establish a communication state between an outer vent passage 16 to be described later and the upper and lower air inlet passages 6 and 7.

Reference numerals 12 and 13 denote side plates installed on both sides of the exhaust pipe 1 in line contact with each other. The upper surfaces thereof are fixed to the upper plate 3 and the lower surfaces thereof are fixed to the lower plate 4. Is done. The rear ends of the side plates 12 and 13 are fixed to the rear end plate 9, but the front ends are not fixed to the front end plate 5, but a ventilation gap 14 is provided.

With this configuration, the exhaust pipe 1, the upper and lower plates 3, 4 and the left and right side plates 1 are arranged around the exhaust pipe 1.
Four inner air passages 15 are formed, which are surrounded by the side plates 12 and 13, and are defined by the side plates 12 and 13 and the shell 2 outside the side plates 12 and 13, and the inner air passage 15 is formed through the ventilation gap 14. Outer air passage 1 communicating with air passage 15
6 are formed.

The portion of the shell 2 behind the exhaust pipe 1 includes upper and lower plates 3 and 4 and left and right side plates 1.
A combined exhaust pipe 17 communicating with the exhaust pipe 1 and having a square cross section formed by 2 and 13 is obtained. And the merging exhaust pipe 1
A rear end exhaust pipe 8 is attached to the rear end of the rear end 7 so as to protrude from the rear end plate 9.

In the above configuration, when the vehicle is stopped (idling), when the engine is started, exhaust gas a having a high temperature and a high pressure with respect to the atmospheric pressure is discharged from the circular exhaust pipe 1 to the combined exhaust pipe 17. , The exhaust pipe 1
, A negative pressure force sucked by the exhaust gas a acts on the ventilation path 15 around. The negative pressure acts on the outer ventilation passage 16 which communicates with the inner ventilation passage 15 via the ventilation gap 14.

The outer ventilation path 16 is provided with the ventilation port 10,
Since the upper and lower atmosphere inflow channels 6 and 7 communicate with each other via the upper surface 11, the negative pressure extends to the upper and lower atmosphere inflow channels 6 and 7. As a result, the atmosphere b is sucked, flows into the upper atmosphere inflow path 6 and the lower atmosphere inflow path 7, and collides with the rear end plate 9. The air b colliding with the rear end plate 9 is supplied to the vents 10 and 11 respectively.
Then, the air flows into the outside ventilation passage 16 (arrow c), flows in the direction opposite to the flow in the upper and lower air inflow passages 6 and 7, and eventually collides with the front end plate 5.

The air colliding with the front end plate 5 is drawn into the four inner ventilation paths 15 around the exhaust pipe 1 through the ventilation gap 14, and flows there in the same direction as the flow of the exhaust gas a to join. It flows into the exhaust pipe 17 and mixes with the exhaust gas a. When the high-temperature and high-pressure exhaust gas is mixed with the low-temperature atmosphere in this way, the temperature of the exhaust gas is reduced and the exhaust gas shrinks, so that the pressure is reduced and a silencing effect occurs. The range of silencing can be controlled by the amount of air introduced.

On the other hand, during traveling, traveling pressure is generated in the atmosphere by traveling, and the atmosphere b naturally flows in from the upper and lower atmosphere inflow passages 6 and 7, and the rear end plate 9
Then, the air flows from the vents 10 and 11 into the outer ventilation passage 16 (arrow c), and flows therethrough in a direction opposite to the flow in the air inflow passages 6 and 7. And the front end play
5, the air flows into the four inner ventilation paths 15 through the ventilation gaps 14 (arrows d), and the air flow paths 6,
The gas flows in the same direction as the flow in 7 and flows into the merged exhaust pipe 17 (arrow e), and is mixed with the exhaust gas a.

Needless to say, as the traveling speed increases, the amount of air flowing from the upper and lower air inflow passages 6 and 7 increases.
In addition, when the engine speed increases, the amount of exhaust gas increases and the exhaust gas pressure also increases, so that the negative pressure suction effect due to exhaust gas discharge generated when the vehicle stops is further increased in this case.

The embodiment shown in FIG.
At the back side of G, a silencing room 20 conventionally used is added. Although the illustrated silencer 20 is of an expansion type, it is not limited to this. In this case, the rear end exhaust pipe 8 is installed behind the sound deadening chamber 20.

In the embodiment shown in FIGS. 7 and 8, the sectional shape of the shell 2 is changed. The one shown in FIG. 7 is an ellipse, and the one shown in FIG. 8 is a square. However, various shapes other than these can be adopted. Note that FIGS. 7A and 8A are diagrams corresponding to FIG. 4, respectively, and FIGS. 7B and 8B are diagrams corresponding to FIG. 5, respectively. The description of the part indicated by is omitted.

[0018]

The present invention is as described above. When the vehicle is stopped, a negative pressure suction effect due to exhaust gas exhaust is provided.
During traveling, low-temperature air can be introduced into high-temperature and high-pressure exhaust gas by the traveling pressure in addition to the suction effect of the negative pressure, and the muffler sound can be reduced by lowering the pressure and temperature of the exhaust gas. There is an effect that the sound can be muted.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a partially omitted plan view of an embodiment of the present invention.

FIG. 3 is a partially omitted side view of an embodiment of the present invention.

FIG. 4 is a diagram showing one embodiment of the present invention as viewed from the front side.

FIG. 5 is a view of one embodiment of the present invention as viewed from the rear side.

FIG. 6 is a partially omitted plan view of another embodiment of the present invention.

FIG. 7 is a view showing still another embodiment of the present invention.

FIG. 8 is a view showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust pipe 2 Shell 3 Upper plate 4 Lower plate 5 Front end plate 6 Upper air inflow path 7 Lower air inflow path 8 Rear end exhaust pipe 9 Rear end plate 10 Vent 11 Vent 12 Side plate 13 Side plate 14 Ventilation gap 15 Inner ventilation path 16 Outer ventilation path 17 Combined exhaust pipe 20 Silencer

Claims (2)

[Claims] 1. An engine-side exhaust pipe and a shell having an exhaust pipe at one end thereof and holding an air inflow path at the top and bottom or left and right thereof and having an exhaust gas ejection opening at the other end. The insertion portion in the shell of the exhaust pipe is formed by covering two plates forming the air inflow channel extending over substantially the entire length of the shell and two side plates perpendicular to the plate in a square shape. The plate and the outer peripheral surface of the exhaust pipe provide four inner ventilation paths around the exhaust pipe, and two inner plates between the two side plates forming the inner ventilation path and the shell. An muffler for an internal combustion engine, wherein an outer ventilation path is provided, and ventilation holes are formed at both innermost corners of the air inflow path. 2. The muffler for an internal combustion engine according to claim 1, wherein a silencing chamber of an appropriate type is continuously provided on a rear surface of said shell.