WO2005010324A1

WO2005010324A1 - Exhaust silencer of internal combustion engine

Info

Publication number: WO2005010324A1
Application number: PCT/KR2004/001749
Authority: WO
Inventors: Hoon Kee Kang
Original assignee: Hoon Kee Kang
Priority date: 2003-07-29
Filing date: 2004-07-14
Publication date: 2005-02-03
Also published as: KR200333249Y1

Abstract

The invention provides an exhaust silencer of internal combustion engine comprising: a housing that has an inlet and an outlet for the exhaust gas to pass through, the housing having guide portions formed at its inner wall; a noise silencing tube that is installed at the inside of the housing, the noise silencing tube being closed at its front end, the noise silencing tube being formed on its surface with a number of noise reducing holes at symmetric positions for reducing the wave length of the exhaust gas noise; and a division to divide the housing, the division being installed at the rear end portion of the noise silencing tube.

Description

EXHAUST SILENCER OF INTERNAL COMBUSTION ENGINE

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to an exhaust silencer

of internal combustion engine that can effectively remove

noise from the exhaust gas produced out of an internal

combustion engine without reducing the engine power,

wherein it is possible to fix a noise silencing tube within

the housing at low expenses with a convenient simple work

step, and more particularly to an exhaust silencer of

internal combustion engine wherein the space within the

housing can be secured so wide that the overall structure

of the exhaust silencer can be made smaller and lighter.

DESCRIPTION OF THE RELATED ART The present applicant filed in the past an invention

on an exhaust silencer of internal combustion engine under

Korean Patent Application No. 2001-0054179, of which the

composition disclosed is as follows:

As is shown in Fig. 1, this exhaust silencer of

internal combustion engine comprises a housing 70, 1st

silencing cylindrical pipe 11a, 2nd silencing rectangular

pipes 20, No.l partition wall 30, 3rd silencing rectangular pipes 40, No.2 partition wall 50, 4th silencing rectangular

pipes 60, and exhaust tube 80.

In Fig. 1, the exhaust gas out of an internal

combustion engine is introduced through an exhaust pipe 11

into the housing 70, of which the top plane 73 and the

bottom plane 75 are formed as one body.

The 1st silencing cylindrical pipe 11a, actually as

an extension part of the exhaust pipe 11, is disposed

within the housing 70 and has a number of slits 17 formed. Two or more of the 2nd silencing rectangular pipes 20

have on both lateral planes a number of slits 27 formed at

face-to- face positions, wherein the exhaust gas that has

been discharged out of the slits 17 of the 1st silencing

cylindrical pipe 11a is introduced through the slits 27

into the 2nd silencing rectangular pipes 20. And the 2nd

discharge opening 25 is formed in order to discharge the

exhaust gas that has been introduced through the slits 27.

No.l partition wall 30 has a number of rectangular

grooves 33 formed in connecting relation to the 2nd

discharge opening 25, and is installed to cover from the

top plane 73 of the housing 70 to the bottom plane 75.

Two or more of the 3rd silencing rectangular pipes 40

have on both lateral planes a number of slits 47 formed at face-to-face positions, wherein the exhaust gas that has

been discharged out of the 2nd discharge opening 25 is

introduced through the slits 47 into the 3rd silencing

rectangular pipes 40. And 3rd discharge opening 45 is

formed in order to discharge the exhaust gas which has been

introduced through the slits 47.

No.2 partition wall 50 has a number of rectangular

grooves 53 formed in connecting relation to the 3rd

discharge opening 45, and is installed to cover from the

top plane 73 of the housing 70 to the bottom plane 75.

Two or more of the 4th silencing rectangular pipes 60

have on both lateral planes a number of slits 67 formed at

face-to-face positions, so that the exhaust gas that has

been discharged out of the 3rd discharge opening 45 can be

introduced through the slits 67.

The exhaust tube 80 is installed in connecting

relation to the outlet-side of the 4th silencing

rectangular pipes 60 in order to discharge the noise-free

exhaust gas from the 4th silencing rectangular pipes 60 to

the atmosphere .

By the way, the exhaust gas being discharged out of

an engine has a tremendous noise and energy as a result of

dynamic explosion power of the engine. Therefore, the exhaust gas is discharged out of an engine through an

exhaust pipe 11, and is introduced into the housing 70

through a number of slits 17 formed in the 1st silencing

cylindrical pipe 11a, wherein the exhaust gas passes

through a number of slits 17 so that its energy and noise

can be reduced on first stage. This exhaust gas is

introduced into the 2nd silencing rectangular pipe 20

through a number of slits 27, wherein the slits 27 are

formed at mutual opposing positions on both lateral planes

of the 2nd silencing rectangular pipes 20 so that the

exhaust gas inflows collide with one another, which causes

energy and noise to be reduced once again.

Then, the exhaust gas within the 2nd silencing

rectangular pipes 20 moves through the 2nd discharge

opening unto the 3rd silencing rectangular pipes 40, and is

introduced through a number of slits 47 into the inside of

the 3rd silencing rectangular pipes 40. In the same way

described as above, the exhaust gas inflows introduced

through the slits 47 that are disposed at mutual opposing

positions collide with one another so that their energy and

noise can be reduced.

At last stage, the exhaust gas discharged through the

3rd discharge opening 45 is introduced through a number of slits 67 into the inside of the 4th silencing rectangular

pipes 60. In the same way, the exhaust gas inflows collide

with one another so that the energy and noise are reduced

lastly. Then, the exhaust gas is discharged out to the

atmosphere through the exhaust tube 80 that is disposed in

connecting relation to the outlet side of the 4th silencing

rectangular pipes 60. So, the overall noise-removing

efficiency can be largely improved.

According to a traditional art described as above,

the exhaust silencer in the past could reduce the noise

very effectively. However, because it uses a number of

rectangular pipes and partition walls, it also has such a

problem that high expenses and many work processes are

required to fix the rectangular pipes and partition walls

within the housing. Due to a number of rectangular pipes

and partition walls, the traditional exhaust silencer of

related art has a disadvantage that the space within the

housing would be made relatively small; and due to No.l

partition wall and No .2 partition wall, a high-pressure

exhaust gas stays so long within the exhaust silencer that

the engine power would rather be made lower.

Moreover, the rectangular pipes for reducing noise

according to the traditional art have such a structure that the silts cannot be formed on its top-side or o bottom-

side. So, the cross-sectional area of slits in total is to

be small, which hinders noise reduction effect from getting

the maximum value . With reference to the shape of the rectangular pipes,

the cross-sectional area at one end of the rectangular

pipes is formed generally same as that at the other end,

which limits the noise reduction effect.

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to an

exhaust silencer of internal combustion engine that

substantially obviates one or more of the problems because

of limitations and disadvantages of the related art. An object of the present invention is to provide an

exhaust silencer of internal combustion engine having a

structure that can effectively remove the noise of exhaust

gas without reducing the engine power, wherein the noise

reduction means can be fixed at the inside of the housing

at low costs with a convenient simple work step, and

particularly wherein the space within the housing can be

secured so widely that the overall structure of the exhaust

silencer can be made smaller and lighter. Another object of the present invention is to provide

an exhaust silencer of internal combustion engine that can

reduce the noise remarkably by transformation put on the

shape of the rectangular pipes or of the slits that are

formed on the rectangular pipes by a traditional art,

particularly wherein the cross-sectional area at one end of

the rectangular pipe is formed so different from that at

the other end that the exhaust gas noise might be reduced

more effectively. Another further object of the present invention is to

provide an exhaust silencer of internal combustion engine

wherein, when the exhaust gas is introduced, both the

exhaust gas stream being discharged with rotation to

radiation direction and the exhaust gas stream proceeding

to horizontal direction collide with each other because of

the different flow angles and rotating force so that a

turbulent flow is formed, which can remarkably reduce the

wave length of the exhaust noise.

To achieve these objectives, the exhaust silencer

according to the present invention comprises: a housing

which has an inlet and an outlet so that the exhaust gas

might pass through, the housing being formed on its inner

wall with guide portions; a noise silencing tube which is disposed at inside of the housing, the noise silencing tube

being closed at its front end portion, the noise silencing

tube being formed on its surface at symmetric positions

with a number of noise reduction holes that can reduce wave

length of the exhaust gas, the noise silencing tube being

formed on its outer wall with fixing portions that are to

be fixed and fitted to the guide portions of the housing,

the noise silencing tube being formed at its rear end

portion with a discharge opening for guiding the exhaust

gas that has flowed in through the noise reduction holes to

proceed toward the outlet-side of the housing; and a

division to divide the housing, the division being

installed at the rear end portion of the noise silencing

tube, the division being formed with a passage hole for

discharging out the exhaust gas that has flowed in through

the noise reducing holes.

The noise silencing tube described as above is

characterized by that its cross section has a shape of an

oval so that both intake quantity of the exhaust gas and

noise reduction effect can be made maximum.

The noise silencing tube described as above is

characterized by that its cross-sectional area is designed

to have a profile that it gets higher as it comes nearer from inlet-side of the housing to outlet-side of the housing so that the back pressure by exhaust gas can be

made minimum.

The noise reduction holes described as above are

characterized by that they are formed to have a crescent

moon shape that bulges in accordance with the direction

toward the discharge outlet-side of noise silencing tube so

that, when the exhaust gas is introduced, the noise wave

length is dispersed according to radiating direction so as

to be reduced.

The noise reduction holes described as above are

characterized by that their size decreases in accordance

with the direction toward the discharge outlet-side so that

the total area intake quantity of exhaust gas being

introduced into the noise silencing tube might be made

balanced.

Moreover, it is characterized by that, at the inside

of the housing, two or more of the noise silencing tubes

described as above are equipped with in a series array or

in a parallel array, and one or more of the divisions are

equipped with in correspondence to the number of the noise

silencing tubes so that the noise reduction effect on

exhaust gas might be doubled. It is characterized by that the exhaust silencer

according to the present invention further comprises a

turbulent producing tube that is disposed at front end

portion of the noise silencing tube and has on its surface

a number of slits formed, whereby on the introduction of

the exhaust gas, an exhaust gas stream proceeding to

radiating direction after passing through the slits

collides with another exhaust gas stream proceeding to

horizontal direction so that the wave length of exhaust gas

might be offset and reduced.

It is characterized further by that the inner wall of

slits formed on the turbulent producing tube described as

above is formed with an inclined angle so that an exhaust

gas stream being discharged to radiating direction after

passing through the slits might have a rotating force

doubled so as to produce more turbulent flows .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to

provide a further understanding of the present invention

and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and

together with the description serve to explain the principles of the invention.

In the drawings :

FIG. 1 is a partially cut-open perspective view

showing an exhaust silencer of internal combustion engine

according to a traditional art;

FIG. 2 is a perspective view showing an exhaust

silencer of internal combustion engine according to the

present invention;

FIG. 3 is an exploded perspective view showing an

exhaust silencer of internal combustion engine according to

the present invention;

FIG. 4 is a side sectional view showing an exhaust

silencer of internal combustion engine according to the

present invention; FIG. 5 is a front sectional view according to the

section V-V of FIG. 4;

FIG. 6 is an exploded perspective view showing

another embodiment of an exhaust silencer of internal

combustion engine according to the present invention; FIG. 7 is a side sectional view showing another

embodiment of FIG. 6 for an exhaust silencer of 'internal

combustion engine according to the present invention;

FIG. 8 is a side sectional view showing further embodiment of an exhaust silencer of internal combustion

engine according to the present invention;

FIG. 9 is a cross sectional view according to the

section IX-IX of FIG. 8; and FIG. 10 & FIG. 11 are side sectional views showing

various embodiments of the exhaust silencers of internal

combustion engine according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, preferred embodiments of the exhaust

silencer of internal combustion engine according to the

present invention will be described in detail with

reference to accompanying drawings. In the drawings, the

composing elements identical to those described before are

levied with same reference numbers, and a new composing

element is levied with a new reference number for

description. Detailed explanation on the same repeated

composing element is to be omitted.

In the drawings, FIG. 2 is a perspective view showing

an exhaust silencer of internal combustion engine according

to the present invention; FIG. 3 is an exploded perspective

view showing an exhaust silencer of internal combustion

engine according to the present invention; FIG. 4 is a side sectional view showing an exhaust silencer of internal

combustion engine according to the present invention; and

FIG.5 is a front sectional drawing showing an exhaust

silencer of internal combustion engine according to the

present invention.

As is shown in the drawings, the exhaust silencer 100

of internal combustion engine according to the present

invention includes a housing 110, a noise silencing tube

120, and a division 130. The housing 110 has an inlet 111 and an outlet 112

for an exhaust gas to flow through. To the inlet 111, an

exhaust gas introducing tube 11 is connected so as to

introduce the exhaust gas that has been discharged out of

an engine (not shown in the drawing) . The noise-reduced

exhaust gas after passing through the inside of the housing

110 is .discharged through the outlet 112 out of the system.

Of course, an exhaust gas discharging tube 80 (see FIG. 1)

can also be equipped with, if necessary for carrying out

the present invention. Moreover, at inner wall of the housing 110, guide

portions 113 are formed on such positions of which interval

is uniform. According to the embodiment shown at the

drawing, the two guide portions are formed by the style of two fixing grooves disposed up and down at opponent inner wall of the housing.

There is a noise silencing tube 120 installed at

inside of the housing 110, wherein the front end is closed;

on its surface, a number of noise reducing holes 121 are

formed at symmetric positions to reduce the wave length of

exhaust gas noise, the size of noise reducing holes 121

getting smaller on positions nearer to the rear end; on its

outer wall, fixing portions 122 are formed to fix and fit

to the guide portions 113 of the housing 110; and at its

rear end, a discharge opening 123 is formed so that the

exhaust gas introduced through noise reducing holes 121 can

be guided to flow toward the outlet 112 of the housing 110.

The noise silencing tube 120 has the shape of an oval

approximately. The inlet portion 124 of the noise silencing

tube 120 is closed so that the exhaust gas that has been

introduced into inside of the housing 110 can flow in only

through the noise silencing holes 121, while the outlet

portion 123 of the noise silencing tube 120 is open so that

the exhaust gas that has been introduced through the noise

reducing holes 121 into the inside of the noise silencing

tube 120 can be discharged outwards.

On the other hand, the shape of the noise silencing tube 120 shown by this embodiment is an oval-type but it

can be modified to a variety of different shapes, for

example, a polygonal tube type or a cylindrical tube type

on condition that such a modified tube can easily be fixed

and fitted at the inside of the housing 110, and as to the

arrangement style of the noise reducing holes 121 formed on

the noise silencing tube 120, it is obvious that it can be

not only a regular array but also a intersecting

combination array. Moreover, those who are skilled in the present

technical field can easily modify to operate the fixing

portions and the guide portions according to various

modifications. For example, the fixing portions 122 can be

formed on inner wall of the housing 110 and the guide

portions 113 can be formed on outer wall of the noise

silencing tube 120 so that they can be fixed mutually.

A division 130 to divide the housing 110 is installed

in connection to the rear end of the noise silencing tube

120, wherein its central portion is a passage hole 131 for

discharging the exhaust gas that has been introduced

through the noise-reducing holes 121. The division 130 of

the present embodiment is designed as a circular bowl type

or a parabolic type so as to get a certain tension. By this tension, the division 130 is fitted at the inside of the

housing 110 with close adherence to the inner wall of the

housing 110.

Preferably, the division 130 is formed with a fitting

portion 132 which is to be fitted firmly for fixing and

connecting to the rear end 125 of the noise silencing tube

120. Now, it is apparent to those skilled in the present

art that various modifications and variations can be made

for the division 130 not only by the forced fitting method

described as above according to a fitting portion 132 of

the division 130 but also by any other methods for fixing

tightly in connection to the housing 110 and the noise

silencing tube 120.

FIG. 6 is an exploded perspective view showing

another embodiment of an exhaust silencer of internal

combustion engine according to the present invention, and

FIG.7 is a side sectional view showing another embodiment

of FIG 6 for exhaust silencer of internal combustion engine.

As it is shown in the drawings, the noise reducing

holes 121 are formed as a crescent moon shape that bulges

in accordance with a direction toward the discharge opening

123 of the noise silencing tube 120 so that the wave length

of noise, when the exhaust gas is introduced, can be dispersed to radiation direction and be reduced. In other

words, the noise reducing holes 121 has a unique shape with

no center, whereby while the wavelength of exhaust gas

noise passes through the noise reducing holes 121, it

disperses to radiation directions so that the exhaust gas

stream produces turbulent flows. The shapes of the noise

reducing holes 121 are, in order that the dispersion effect

of noise wavelength can be made maximum, suggested as ^• a

crescent moon type, but other modifications or variations

such as an arc type or a wave type that has no center can

also be possible for other embodiments.

In addition, as the noise reducing holes 121 come

nearer to the discharge opening 123, their sizes are formed

smaller so that the total area intake quantity of the

exhaust gas that is introduced into the inside of noise

silencing tube 120 can be made balanced, which can be

explained as follows: The exhaust gas flow has a strong

tendency to proceed toward the direction of horizontal rear

end portion. So, at the place close to the discharge

opening 123 of the noise silencing tube 120, the gas intake

quantity is large, and on the other hand at the place close

to the front end 124 of the noise silencing tube 120, the

gas intake quantity to be taken through the noise reducing holes 121 is relatively small. This phenomenon means that,

if all the sizes of the noise reducing holes 121 are

assumed to be constant and unchanged, the gas intake

quantity by the noise reducing holes 121 disposed near to

front end 124 of the noise silencing tube 120 is relatively

smaller than that by the noise reducing holes 121 disposed

near to the discharge opening 123 of the noise silencing

tube 120. In order to prevent this problem, the size of the

noise reducing holes 121 should be regulated. Then, the

total area intake quantity on exhaust gas being introduced

through noise reducing holes 121 is made balanced so that

the noise-reducing effect can be doubled. Preferably, the

cross-sectional area of the noise silencing tube 120 at the

outlet-side 112 of the housing 110 is larger than that at

the inlet-side 111 of the housing 110, and the sectional

area distribution increases progressively from the inlet-

side 111 to the outlet-side 112 so that the back pressure

by exhaust gas is to be made minimum. In consideration that

the pressure of exhaust gas just produced and discharged

out of the internal combustion engine is very high, the

exhaust gas is made to be discharged out as soon as

possible from the housing 110 outward so that its retention

time for staying inside the noise silencing tube 120 might be minimized, which can then prevent the engine power from

being reduced.

Hereinafter, the principle and operation process of

the exhaust silencer of internal combustion engine

according to the present invention will be described in

detail with reference to the accompanying drawings.

At first, the fixing portions 122 of noise silencing

tube 120 can be easily and conveniently fitted to be fixed

in connection to the guide portions 113 formed at inside of

the housing 110 so that an additional welding or connecting

means is not necessary for the noise silencing tube 120 to

be installed, which enables number of working steps or

mechanical parts to be reduced. In addition, a number of

noise reducing holes 121 are formed on all the surface of

the^' noise silencing tube 120, which makes it possible that

the total area assigned for noise-removal increases

remarkably even when one or two of the noise silencing

tubes 120 are installed. Moreover, overall inside structure

of the housing 110 is designed not only to be very simple

and compact but also to have a sufficient inner space of

the housing 110 so that it can prevent the back pressure of

exhaust gas, whereby the reduction of engine power can be

avoided. Secondly, when the exhaust gas once produced from the

internal combustion engine is introduced through the

exhaust gas inflow tube 11, the exhaust gas collides with

the front end of noise silencing tube 120, and then the

exhaust gas changes its flow direction to flow through the

noise reducing holes 121 of the noise silencing tube 120

into the inside of the noise silencing tube 120. Now, the

shape of the noise reducing holes 121 is a crescent moon

shape that has no core or center, whereby the wave lengths

of the exhaust gas noise, on being introduced through the

noise reducing holes 121, are dispersed and scattered out

to radiation directions so that the noise can be reduced.

Moreover, a number of noise reducing holes 121 are disposed

at mutual opposing positions, whereby the noise wave

lengths will collide reciprocally one another at inside of

the noise silencing tube 120 so as to be offset and reduced

drastically.

These wavelengths, after they have been offset as

described as above to have reduced noise, are discharged

outwards through the discharge opening 123 of the noise

silencing tube 120.

In conclusion, the exhaust silencer 100 according to

the present invention is a very excellent invention whereby the exhaust noise might be removed effectively without

reducing the engine power, and at the same time it is

possible to fix the noise silencing tube 120 at the inside

of the housing 110 at low cost with a conveniently simple

work step. Moreover, the space within the housing 110 can

be secured so particularly wide that the overall structure

of the exhaust silencers 100 and 200 might be made smaller

and lighter.

FIG. 8 is a side sectional view showing an exhaust

silencer of internal combustion engine according to another

embodiment of the present invention, and FIG. 9 is a

sectional view according to the section IX-IX of FIG.8,

wherein the composing element identical to that described

as above is levied with same reference number, and a new

composing element is levied with a new reference number for

description. However, a detailed explanation on the same

repeated composing element is to be omitted.

As it is shown in the drawings, the invention

according to the present embodiment comprises a housing 110,

a noise silencing tube 120 and a division 130, and further

comprises a turbulent producing tube 210 which is disposed

at the front end of the noise silencing tube 120, the

surface of the turbulent producing tube 210 being formed with a number of slits 211, wherein, on introduction of the

exhaust gas, the exhaust gas stream discharged out to

radiation direction through the slits 211 collides with the

exhaust gas stream discharged to horizontal direction so

that the wave length of exhaust gas noise might be reduced.

Preferably, the inner wall of each of slits 211 of

the turbulent producing tube 210 is formed with inclination.

More preferably, the diameter of turbulent producing

tube 210 is formed to be bigger than that of exhaust gas

introducing tube 11, whereby the exhaust gas introduced

into the inside of housing 110 is to be introduced into the

turbulent producing tube 210, and then a part of the

introduced exhaust gas, as it is shown in the drawings, is

discharged out through the slits 211 and the remnant part

bounds out to flow in through the noise reducing holes 121

of the housing 110.

The turbulent producing tube 210 comprising as

described as above is a cylindrical tube shape that is

opened at the side of exhaust gas introducing tube 11,

wherein a part of exhaust gas introduced through the

exhaust gas introducing tube 11 once flows into the inside

of the turbulent producing tube 210. Then, a part of the

exhaust gas inflow is rotating and discharged out to radiation direction through the slits 211 (see FIG. 9) , and

the remnant collides with the inner wall so as to bound out

until the outside of turbulent producing tube 210 and again

flows further according to the horizontal direction toward

outlet-side 112 of the housing 110.

Accordingly, the exhaust gas stream proceeding with

rotation movement to radiation direction through the slits

211 collides reciprocally with the exhaust gas stream

proceeding to horizontal direction, which produces a

turbulent flow so that the wave lengths of exhaust gas

noise might finally be offset and that the noise might be

reduced remarkably.

Moreover, because the inner wall of the slits 211 of

the turbulent producing tube 210 is formed with an^'

inclination angle', the exhaust gas stream being discharged

out through the slits 211 with rotating movement to

radiation directions can have a rotating force doubled, and

the exhaust gas stream proceeding to radiation directions

through the slits 211 collides reciprocally with the

exhaust gas stream proceeding to horizontal direction due

to different direction angles and rotating forces. So,

turbulent flows can be produced and the noise wave lengths

can be reduced remarkably. The remaining parts of the exhaust silencer 200 such

as the noise silencing tube 120 and its composing elements

or its performance are to be omitted here because they are

the same as those described before. FIG. 10 and FIG. 11 are side sectional views showing

the exhaust silencers of internal combustion engine

according to other various embodiments of the present

invention.

As it is shown in the drawings, at inside of the

housing 110, two or more of the noise silencing tubes 120

are installed in a series array or in a parallel array, and

one or more of the divisions 130 corresponding to the

number of the noise silencing tubes 120 are installed so

that the noise reduction effect of exhaust gas can be made

doubled. The exhaust gas stream is to be guided unto two or

more of the noise silencing tubes 120 and follows the same

principles and processes described as above repeatedly for

the corresponding number of steps so that the wave lengths

of exhaust gas might be reduced drastically.

Industrial Applicability The exhaust silencer of internal combustion engine

according to the present invention described as above has

features and advantages that it can effectively remove the noise from the exhaust gas of internal combustion engine

without reducing the engine power, that it is possible to

fix the noise silencing tube at the inside of the housing

with low expenses and by conveniently simple work steps,

and particularly that the space within the housing can be

secured so widely that the overall structure of the exhaust

silencer can be made smaller and lighter in comparison with

the exhaust silencer of a traditional art.

Moreover, the present invention has another feature

and advantage that the shape of slits formed at the noise

silencing tube can be modified so that the noise might be

reduced remarkably, and particularly that the sectional

area at one end of the noise silencing tube is made to be

different from that at the other end of the noise silencing

tube so that the back pressure by the exhaust gas might be

made to be minimum, which can prevent the engine power from

being lowered.

Moreover, the present invention has another further

feature and advantage that, on the exhaust gas being

introduced, the exhaust gas stream proceeding to radiation

directions collides with the exhaust gas stream proceeding

to horizontal direction due to different movement angles

and rotating forces so that a turbulent flow can be produced, which can also reduce the wave length of the

exhaust gas noise drastically.

So far, the present invention has been described and illustrated in detail according to particular preferable embodiments and with reference to particular drawings shown as above. However, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention covers the modifications and variations of this invention that come with scope of the appended claims and their equivalents.

Claims

What is claimed is: 1. An exhaust silencer of internal combustion engine

comprising: a housing that has an inlet and an outlet for the

exhaust gas to pass through, the housing having guide

portions formed at its inner wall; a noise silencing tube that is installed at the

inside of the housing, the noise silencing tube being

closed at its front end, the noise silencing tube being

formed on its surface with a number of noise reducing holes

at symmetric positions for reducing the wave length of the

exhaust gas noise, the noise silencing tube being formed on

its outer wall with fixing portions that are to be fixed

and fitted to the guide portions of the housing, the noise

silencing tube being formed at its rear end with a

discharge opening for guiding the exhaust gas that has

flowed in through the noise reducing holes to proceed

toward the outlet-side of the housing; and a division to divide the housing, the division being

installed at the rear end portion of the noise silencing

tube, the division being formed with a passage hole for

discharging out the exhaust gas that has flowed in through

the noise reducing holes.

2. The exhaust silencer of internal combustion engine

according to claim l,and wherein the noise silencing tube

is designed so that its cross-sectional shape is an oval in

order to maximize both the exhaust intake quantity and the noise reduction effect.

3. The exhaust silencer of internal combustion engine

according to claim 1, and wherein the noise silencing tube

is designed so that its cross-sectional area increases

progressively from the inlet-side of the housing toward the

outlet-side of the housing in order to minimize the back

pressure by the exhaust gas.

4. The exhaust silencer of internal combustion engine

according to claim 1, and wherein the noise reducing holes

are formed so that their size decreases progressively in

accordance with a direction toward the discharge opening

for making balanced the total area^' intake quantity of

exhaust gas that flows into the noise silencing tube.

5. The exhaust silencer of internal -combustion engine

according to claim 1, and wherein the noise reducing holes are formed as a crescent moon shape that bulges in

accordance with a direction toward the discharge opening of

the noise silencing tube so that the noise wave length, on

the introduction of the exhaust gas, might be dispersed to

radiation direction and be reduced.

6. The exhaust silencer of internal combustion engine

according to claim 1, and wherein two or more of the noise

silencing tubes are installed in a series array or in a

parallel array at the inside of the housing and one or more

of the divisions are installed in correspondence to the

number of the noise silencing tubes so that the noise

reduction effect on the exhaust gas might be made higher

even up to double.

7. The exhaust silencer of internal combustion engine

according to claim 1 further comprising a turbulent

producing tube that is installed at the front end of the

noise silencing tube, the turbulent producing tube being

formed on its surface with a number of slits so that, on

the introduction of the exhaust gas, the exhaust gas stream

being discharged through the slits to radiation direction

collides with the exhaust gas stream being discharged to horizontal direction in order to reduce the noise wave

length of exhaust gas.

8. The exhaust silencer of internal combustion engine

according to claim 7, and wherein the inner wall of the

slits on the turbulent producing tube are formed with an

inclined angle so that the exhaust gas stream being

discharged through the slits to radiation direction might

have higher rotating force in order to produce more

turbulent flows.