U.S. patent application number 10/540492 was filed with the patent office on 2006-11-09 for muffler for motor vehicle.
Invention is credited to Hiroyuki Ichikawa, Sumito Mochizuki, Takumi Okano, Shinya Okuma.
Application Number | 20060249328 10/540492 |
Document ID | / |
Family ID | 32685838 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060249328 |
Kind Code |
A1 |
Ichikawa; Hiroyuki ; et
al. |
November 9, 2006 |
Muffler for motor vehicle
Abstract
An object of the present invention is to design miniaturization
of a muffler as performance of the muffler is maintained and to
exhibit appropriate gas-exhausting characteristics in accordance
with traveling condition of a vehicle. The present invention is to
provide a muffler for a motor vehicle provided on an exhaust
passage of an engine installed on the vehicle, comprising a casing
main body which is located most outside; an exhaust gas introducing
pipe constituting an end portion of the exhaust gas passage,
including an extending portion extending into said casing main body
and having a plurality of small holes in said extending portion; a
finisher located on an extending line of said exhaust gas
introducing pipe and including an inner portion positioned inside
said casing main body and an extending portion extending from said
casing main body; a silencer mechanism including expansion spaces
and a constriction mechanism, wherein said expansion spaces are
defined by pipe members arranged at specific intervals outside of a
radial direction of said extending portion of said exhaust gas
introducing pipe and said inner portion of said finisher; and a
valve mechanism provided on an end portion of said exhaust gas
introducing pipe and communicating between said exhaust gas
introducing pipe and said finisher when pressure of the exhaust gas
in said exhaust gas introducing pipe exceeds a specific value.
Inventors: |
Ichikawa; Hiroyuki;
(Kanagawa, JP) ; Mochizuki; Sumito; (Sagamihara,
JP) ; Okano; Takumi; (Sagamihara, JP) ; Okuma;
Shinya; (Sagamihara, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
32685838 |
Appl. No.: |
10/540492 |
Filed: |
December 25, 2003 |
PCT Filed: |
December 25, 2003 |
PCT NO: |
PCT/JP03/16663 |
371 Date: |
June 23, 2005 |
Current U.S.
Class: |
181/254 ;
181/237 |
Current CPC
Class: |
F01N 1/10 20130101; F01N
1/08 20130101; F01N 1/166 20130101 |
Class at
Publication: |
181/254 ;
181/237 |
International
Class: |
F01N 1/16 20060101
F01N001/16; F01N 1/00 20060101 F01N001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2002 |
JP |
2002-376906 |
Apr 17, 2003 |
JP |
2003-112456 |
May 9, 2003 |
JP |
2003-131198 |
Claims
1-22. (canceled)
23. A muffler for a motor vehicle provided on an exhaust passage of
an engine installed in a motor vehicle, comprising a casing main
body positioned most outside; an exhaust gas introducing pipe
constituting an end portion of the exhaust passage and having a
plurality of small holes in an extending portion extending into
said casing main body; a finisher positioned on an extending line
of said exhaust gas introducing pipe and consisting of an inner
portion positioned inside said casing main body and an outer
portion extending out of said casing main body; a plurality of pipe
members arranged concentrically to the extending portion of said
exhaust gas introducing pipe and the inner portion of said finisher
and having different radiuses respectively; a silencer mechanism
constituted of a plurality of expansion spaces and a plurality of
passages constituting a restriction mechanism which are defined by
said pipe members, said exhaust gas introducing pipe, said finisher
and said casing main body; and a valve mechanism provided in an end
portion of said exhaust gas introducing pipe and communicating
between said exhaust gas introducing pipe and said finisher when
pressure of exhaust gas in said exhaust gas introducing pipe has
exceeded a specific value.
24. A muffler for a motor vehicle according to claim 23, wherein:
said pipe members is constituted of a first inner pipe arranged
concentrically at a specific interval inside said casing main body,
and a second inner pipe arranged concentrically at a specific
interval inside said first inner pipe, and said exhaust gas
introducing pipe and said finisher are inserted into said second
inner pipe in both directions.
25. A muffler for a motor vehicle according to claim 24, wherein
said silencer mechanism is constituted of: a first expansion space
defined between said exhaust gas introducing pipe and said casing
main body and communicating to said exhaust gas introducing pipe
via said small holes; a first passage defined between said casing
main body and said first inner pipe and communicating to said first
expansion space; a second passage defined between said first inner
pipe and said second inner pipe and communicating to said first
passage via small holes formed in said first inner pipe; a second
expansion space defined between said finisher and said casing main
body and communicating to said second passage; a third passage
defined between said second inner pipe and said finisher and
communicating to said second expansion space; and a third expansion
space positioned inside said second inner pipe and between said
exhaust gas introducing pipe and said finisher, and communicating
between said third passage and said finisher, said exhaust gas
introducing pipe is communicated to said finisher via said third
expansion space at an opening condition of said valve
mechanism.
26. A muffler for a motor vehicle according to claim 25, wherein:
an acoustic material is arranged in a part which is defined by said
first inner pipe and said second inner pipe and faces to said third
expansion space.
27. A muffler for a motor vehicle according to claim 24, wherein
said silencer mechanism is constituted of: a first expansion space
defined between said exhaust gas introducing pipe and said casing
main body and communicating to said exhaust gas introducing pipe
via said small holes; a first passage defined between said first
inner pipe and said second inner pipe and communicating to said
first expansion space; a second expansion space defined between
said finisher and said casing main body and communicating to said
first passage; a second passage defined between said second inner
pipe and said finisher and communicating to said second expansion
space; and a third expansion space positioned inside said second
inner pipe and between said exhaust gas introducing pipe and said
finisher, and communicating to said second passage and said
finisher, and said exhaust gas introducing pipe is communicated to
said finisher via said third expansion space at an opening
condition of said valve mechanism.
28. A muffler for a motor vehicle according to claim 27, wherein:
an acoustic material is arranged in a space defined between said
casing main body and said first inner pipe.
29. A muffler for a motor vehicle according to claim 24, wherein
said silencer mechanism is constituted of: a first expansion space
defined between said exhaust gas introducing pipe and said casing
main body and communicating to said exhaust gas introducing pipe
via said small holes; a first passage defined between said casing
main body and said first inner pipe and communicating to said first
expansion space; a second expansion space defined between said
finisher and said casing main body and communicating to said first
passage; a second passage defined between said second inner pipe
and said finisher and communicating to said second expansion space;
and a third expansion space positioned inside said second inner
pipe and between said exhaust gas introducing pipe and said
finisher, and communicating to said third passage and said
finisher, and said exhaust gas introducing pipe is communicated to
said finisher at an opening condition of said valve mechanism.
30. A muffler for a motor vehicle according to claim 29, wherein an
acoustic material is arranged between said first inner pipe and
said second inner pipe.
31. A muffler for a motor vehicle according to claim 23, wherein
said pipe members are constituted of: a first inner pipe arranged
concentrically at a specific interval to said exhaust gas
introducing pipe, having a downstream side closing bottom surface
portion fixed on a circumferential surface of said exhaust gas
introducing pipe in a downstream side of said small holes formed on
said exhaust gas introducing pipe in one side thereof, and having
an opening portion in another side thereof; a second inner pipe
arranged concentrically at a specific interval to said exhaust gas
introducing pipe, having an upstream side closing bottom surface
portion fixed on a circumferential surface of said exhaust gas
introducing pipe in a upstream side of said small holes formed on
said exhaust gas introducing pipe in one side thereof, having an
opening portion in another side thereof, and having a larger by a
specific value than one of said first inner pipe; a third inner
pipe overlapped in a specific area to said first inner pipe, a
downstream side end portion of said third inner pipe being
connected to said outer portion of said finisher, having a smaller
radius by a specific value than one of said inner pipe; and a
fourth inner pipe having a smaller radius by a specific value than
one of said third inner pipe, being arranged inside said third
inner pipe to constitute a part of said finisher, having an
upstream side expanding radius portion fixed on an inner surface of
said first inner pipe, a downstream side expanding radius portion
fixed on said outer portion of said finisher and a plurality of
downstream side exhausting holes formed at specific intervals along
a circumferential surface of said downstream side expanding radius
portion.
32. A muffler for a motor vehicle according to claim 31, wherein
said silencer mechanism is constituted of: a first expansion space
defined by said downstream side closing bottom surface portion of
said first inner pipe and said upstream side closing bottom surface
portion of said second inner pipe, and communicating to said
exhaust gas introducing pipe via said small holes; a first passage
defined between said first inner pipe and said second inner pipe
and communicating to said first expansion space; a second expansion
space defined between said second inner pipe and said casing main
body and communicating to said first passage; a second passage
defined between said first inner pipe and said third inner pipe and
communicating to said second expansion space; a third passage
defined between said third inner pipe and said fourth inner pipe
and communicating between said second passage and said downstream
side exhausting holes; and a third expansion space defined inside
said fourth inner pipe and communicating to said downstream side
exhausting holes and an opening of said finisher, and said exhaust
gas introducing pipe is communicated to the opening of said
finisher via said third expansion space at an opening condition of
said valve mechanism.
33. A muffler for a motor vehicle according to claim 31, further
comprising a fifth inner pipe arranged concentrically outside said
second inner pipe, having a closing bottom portion fixed on a
circumferential surface of said third inner pipe at a position
facing to openings of said first inner pipe and said second inner
pipe in a downstream side of an exhausting direction, and having an
opening portion in an upstream side of the exhausting
direction.
34. A muffler for a motor vehicle according to claim 33, wherein
said silencer mechanism in constituted of: a first expansion space
defined by said downstream side closing bottom surface portion of
said first inner pipe and said upstream side closing bottom surface
portion of said second inner pipe, and communicating to said
exhaust gas introducing pipe via said small holes; a first passage
defined between said first inner pipe and said second inner pipe
and communicating to said first expansion space; a fourth passage
defined between said second inner pipe and said fifth inner pipe
and communicating to said first passage; a second expansion space
defined between said second inner pipe and said casing main body
and communicating to said fourth passage; a second passage defined
between said first inner pipe and said third inner pipe and
communicating to said first passage; a third passage defined
between said third inner pipe and said fourth inner pipe and
communicating between said second passage and said downstream side
exhausting holes; and a third expansion space defined inside the
fourth inner pipe and communicating to said downstream side
exhausting holes and an opening of said finisher, and said exhaust
gas introducing pipe is communicated to said opening of said
finisher via said third expansion space at an opening condition of
said valve mechanism.
35. A muffler for a motor vehicle according to claim 31, wherein
said downstream side exhausting holes are square shaped holes.
36. A muffler for a motor vehicle according to claim 31, wherein
said downstream side exhausting holes are streamline shaped
holes.
37. A muffler for a motor vehicle according to claim 23, wherein
said pipe members are constituted of: a first inner pipe arranged
at a specific interval inside said casing main body; and a second
inner pipe arranged at a specific interval inside said first inner
pipe; and a third inner pipe arranged at a specific interval inside
said second inner pipe and constituted of said extending portion of
said exhaust gas introducing pipe.
38. A muffler for a motor vehicle according to claim 37, wherein
said silencer mechanism is constituted of: a first expansion space
defined inside said third inner pipe; a second expansion space
defined by said casing main body and said first inner pipe and
communicating to said first expansion space via said small holes; a
first passage defined by said first inner pipe and said second
inner pipe and communicating to said second expansion space; and a
second passage defined by said second inner pipe and said third
inner pipe and communicating between said first passage and an
opening of said finisher, and said exhaust gas introducing pipe is
communicated to said opening of said finisher via said first
expansion space at an opening condition of said valve
mechanism.
39. A muffler for a motor vehicle according to claim 23, wherein
said valve mechanism is constituted of a valve body which opens and
closes an end of said exhaust gas introducing pipe, a spring
pressing said valve body to the end of said exhaust gas introducing
pipe, and a means for adjusting pressure which adjusts pressure of
said spring.
40. A muffler for a motor vehicle according to claim 39, wherein
said means for adjusting pressure is constituted of a holding
portion for holding one end of said spring and a rotation portion
which make said holding portion move to said valve body to adjust
the pressure of the spring, and said rotation portion can be
rotated through said opening of said finisher.
Description
TECHNICAL FIELD
[0001] The present invention relates to a muffler for a motor
vehicle employing for an engine exhaust in a motor vehicle,
especially having a constitution such that flowing resistance of
the exhaust gas can be changed in accordance with traveling
condition of the vehicle.
BACKGOURND OF THE INVENTION
[0002] As a prior art regarding a muffler (a silencer), JP 9-166010
A discloses a silencer device comprising a casing, a gas intake
tube to the casing, tubes installed in the casing, diaphragms,
supporting elastic members, a piston bar, a pressure container as a
control mechanism providing with pressure connection portions, a
valve closing element attached on the piston bar, and a pressure
introducing tube transmitting a whole gas pressure to a pressurized
side of the diaphragms, wherein the pressure container has a
plurality of chambers defined by the diaphragms, each of the
diaphragms is supported by the elastic members, each of the
chambers has the pressure connection portion, and another pressure
introducing tube transmits the static pressure of the gas to a low
pressure side of the diaphragms. Thus, in the muffler disclosed in
the reference invention, variable attenuation characteristics can
be gained without an outer control device.
[0003] In the prior silencer device, a plurality of tubes which are
communicated between the outside and inside thereof and transmit
the gas between three expansion chambers are arranged in parallel
and perpendicularly, so that there is a disadvantage such that a
size of the whole device must be enlarged.
DISCLOSURE OF THE INVENTION
[0004] Therefore, an object of the invention is to provide a
muffler for a motor vehicle which can achieve appropriate
gas-exhausting characteristics in accordance with traveling
condition of the vehicle while downsizing during maintaining the
performance.
[0005] A muffler for a motor vehicle according to the present
invention, which is provided on an exhaust gas passage of an
internal engine installed on the motor vehicle, comprises a casing
main body which is an outermost shell; an exhaust gas introducing
pipe which constitutes an end of the exhaust gas passage and
includes an extending portion extending into the casing main body,
and further having a plurality of small holes in the extending
portion thereof; a finisher which is located on a line extending
from the exhaust gas introducing pipe and consists of an inner
portion located in the casing main body and an outer portion
extending from the casing main body; a silencer mechanism
consisting of expansion chambers defined by the extending portion
of the exhaust gas introducing pipe and pipe members arranged at
specific intervals in a radial direction outside the inner portion
of the finisher and a constriction mechanism; and a valve mechanism
which is located on an end of the exhaust gas introducing pipe and
which makes communication between the exhaust gas introducing pipe
and the finisher open when exhaust gas pressure in the exhaust gas
introducing pipe has exceeded a specific value.
[0006] Besides, in the present invention, it is preferred that the
pipe members are a first inner pipe located at a specific interval
inside the casing main body and a second inner pipe located at a
specific interval inside the first inner pipe into which the
exhaust gas introducing pipe and the finisher are inserted in
opposite directions; the expansion chambers are constituted of a
first expansion chamber defined between the exhaust gas introducing
pipe and the casing main body, a second expansion chamber defined
between the finisher and the casing main body and a third expansion
chamber defined between the exhaust gas introducing pipe and the
finisher inside the second inner pipe; the constriction mechanism
is constituted of a first passage communicating between the first
expansion chamber and the second expansion chamber and a second
passage communicating between the second expansion chamber and the
third expansion chamber; and the valve mechanism communicates
between the exhaust gas introducing pipe and the finisher via the
third expansion chamber when it has opened.
[0007] Furthermore, the second passage is preferably a space formed
between the second inner pipe and the finisher. The first passage
is preferably constituted of a first space defined between the
first inner pipe and the casing main body and a second space
defined by the first inner pipe and the second inner pipe. It is
preferred that an acoustic material is arranged in an exhaust gas
introducing pipe side of the second space.
[0008] Besides, it is preferred that the first passage is a space
defined between the first inner pipe and the second inner pipe, and
an acoustic material is arranged in a space defined between the
first inner pipe and the casing main body.
[0009] Furthermore, it is preferred that the first passage is a
space defined between the first inner pipe and the casing main
body, and an acoustic material is arranged in a space defined
between the first inner pipe and the second inner pipe.
[0010] It is preferred that the valve mechanism is provided with a
valve body moving so as to open and close the exhaust gas
introducing pipe and an elastic member urging the valve body to a
close direction at a specific pressure, and further a means for
adjusting pressure which can adjust pressure by the elastic member
through the finisher from an outside.
[0011] Furthermore, it is preferred that the valve body is in an
approximately conical shape such as to spread gradually to a
downstream side in a flow direction of exhaust gas and its top is
in a smooth round shape.
[0012] In the present invention, the pipe members are a first inner
pipe which is arranged approximately concentrically relative to the
exhaust gas introducing pipe and which is in a cylindrical shape
with an opening in one side thereof having a downstream side
closing bottom surface portion secured around the exhaust gas
introducing pipe in a downstream side of an exhaust direction of
the small holes; a second inner pipe which is arranged
approximately concentrically relative to the exhaust gas
introducing pipe, which is in a cylindrical shape with an opening
in one side thereof, which has a upstream side closing bottom
surface portion secured around the exhaust gas introducing pipe in
a upstream side of the exhaust direction of the small holes and
which has a radius larger by a specific value than one of the first
inner pipe; a third inner pipe which is overlapped at a specific
area to the first inner pipe, whose downstream end portion is
connected to the finisher, which is in a cylindrical shape with
openings in both ends thereof, and which has a radius smaller by a
specific value than one of the first inner pipe, and a fourth inner
pipe which is arranged inside the third inner pipe and which
includes an upstream side expanding radius portion whose end is
secured on an inner surface of the first inner pipe, a downstream
side expanding radius portion whose end is secure on an inner
surface of the finisher and downstream exhaust holes formed on the
downstream side expanding radius portion. It is preferred that the
silencer mechanism is constituted of a first exhaust passage which
is defined by the first inner pipe and the second inner pipe and
communicate to the small holes, a first expansion space which
defined by the second inner pipe and the casing main body and on
which the first exhaust passage is opened, a second exhaust passage
which is defined the first inner pipe and the third inner pipe and
which is communicated to the first expansion space, a third exhaust
passage which is defined by the third inner pipe and the fourth
inner pipe and which is communicated between the second exhaust
passage and the downstream side exhaust holes, and a second
expansion space which is defined inside the fourth inner pipe, on
which the downstream side exhaust holes are opened and which is
communicated to an opening of the finisher.
[0013] Furthermore, it is preferred that the exhaust gas
introducing pipe is communicated to the opening of the finisher via
the second expansion space when the valve mechanism has been
opened.
[0014] Moreover, it is preferred that a fifth inner pipe is
provided outside of the second inner pipe, has a closing bottom
portion which closes communication between the second exhaust
passage and the first expansion space and connects between the
first exhaust passage and the second exhaust passage, and defines a
fourth exhaust passage which is communicated between the first
exhaust passage and the first expansion space in cooperation with
the second inner pipe.
[0015] Besides, it is preferred that the valve mechanism is
provided with a valve body which makes an end of the exhaust gas
introducing pipe open and close and which is in a convex shape
projecting to the upstream side of the exhaust direction, a spring
pressing the valve body to an end of the exhaust gas introducing
pipe, and a mechanism for adjusting spring pressure. The mechanism
for adjusting spring pressure is preferably constituted of a holder
portion for holding an end of the spring and a rotation portion for
moving the holding portion relative to the valve body to adjust the
spring pressure, and further the rotation portion is preferably
located on a center line of the finisher and can be adjusted from
an opening of the finisher.
[0016] Furthermore, the downstream side exhaust holes are
preferably formed at regular intervals around the downstream side
expanding radius portion of the fourth inner pipe, they are square
shaped holes that upstream sides thereof are opened in a third
exhaust passage side or are streamline shaped holes that upstream
sides thereof are opened in the third exhaust passage side.
[0017] Moreover, a small expansion space is preferably formed
between the downstream side closing bottom surface portion of the
first inner pipe and the upstream side closing bottom surface
portion of the second inner pipe in an upstream side of the first
exhaust passage.
[0018] Besides, the pipe members are preferably constituted of a
first inner pipe which is arranged at a specific interval from an
inner surface of the casing main body, a second inner pipe which is
arranged at a specific interval from an inner surface of the first
inner pipe, and a third inner pipe, wherein a valve mechanism is
provided on a finisher side end of the third inner pipe, and a
silencer mechanism is constituted of spaces defined by the casing
main body, the first inner pipe, the second inner pipe and the
third inner pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a cross section view illustrating a structure of
the muffler for the motor vehicle and a usual traveling condition
according to a first working mode of the present invention;
[0020] FIG. 1B is a cross section view illustrating a structure of
the muffler for the motor vehicle and a high speed traveling
condition according to the first working mode of the present
invention;
[0021] FIG. 1C is a cross section view cutting the cross section
view in FIG. 1A at A-A line;
[0022] FIG. 2A is a cross section view illustrating a structure of
the muffler for the motor vehicle and a usual traveling condition
according to a second working mode of the present invention;
[0023] FIG. 2B is a cross section view illustrating a structure of
the muffler for the motor vehicle and a high speed traveling
condition according to the second working mode of the present
invention;
[0024] FIG. 3A is a cross section view illustrating a structure of
the muffler for the motor vehicle and a usual traveling condition
according to a third working mode of the present invention;
[0025] FIG. 3B is a cross section view illustrating a structure of
the muffler for the motor vehicle and a high speed traveling
condition according to the third working mode of the present
invention;
[0026] FIG. 4 is a cross section view of the muffler for the motor
vehicle according to a fourth working mode of the present
invention;
[0027] FIG. 5A is a front view of the downstream side expanding
radius portion of the fourth inner pipe provided inside of the
finisher;
[0028] FIG. 5B is a cross section view of the downstream side
expanding radius portion of the fourth inner pipe provided inside
of the finisher;
[0029] FIG. 6 is a cross section view of the muffler for the
vehicle according to a fifth working mode of the present
invention;
[0030] FIG. 7A is a front view of the downstream side expanding
radius portion of the fourth inner pipe according to a sixth
working mode;
[0031] FIG. 7A is a cross section view of the downstream side
expanding radius portion of the fourth inner pipe according to a
sixth working mode;
[0032] FIG. 8 is a cross section view illustrating a structure of
the muffler for the motor vehicle and a usual traveling condition
according to a seventh working mode of the present invention;
and
[0033] FIG. 9 is a cross section view illustrating a structure of
the muffler for the motor vehicle and a high speed traveling
condition according to the seventh working mode of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] Hereinafter, working modes of the present invention are
explained by referring the attached drawings.
[0035] A muffler for a motor vehicle 1 according to a first working
mode as shown in FIG. 1A, FIG. 1B and FIG. 1C is constituted of an
exhaust gas introducing pipe 2, a casing main body 3, a finisher 4,
a silencer mechanism 8 and a valve mechanism 6.
[0036] The exhaust gas introducing pipe 2 is to introduce exhaust
gas discharged from an engine to the casing main body 3, is secured
to a front side end of the casing main body 3 via a front side
cover 10 and has a plurality of small holes 12. The casing main
body 3 is a cylindrical member, and a first inner pipe 15, a second
inner pipe 16 and an acoustic material 5 such as a glass-wool are
arranged inside thereof to constitute a silencer mechanism 8 in
which pulsation of the exhaust gas introduced through the exhaust
gas introducing pipe 2 can be decreased.
[0037] The finisher 4 is a pipe-like member for discharging the
exhaust gas passing through the casing main body 3 and is secured
on a rear side end of the casing main body 3 via a rear side cover
11.
[0038] The first inner pipe 15 is a cylindrical member, wherein a
front end thereof is secured to a front side fixture 19 which is
fixed on the exhaust gas introducing pipe 2 and a rear end thereof
is secured on a flange portion 13 of the rear side cover 11. The
second inner pipe 16 is a cylindrical member with smaller radius
than one of the first inner pipe 15 and arranged inside the first
inner pipe 15, wherein a front end thereof is secured on the front
side fixture 19 and a rear end thereof is secured on a rear side
fixture 20 which is fixed on the finisher 4. The acoustic material
5 is filled up in an approximately half front part of a space
between the first inner pipe 15 and the second inner pipe 16.
Furthermore, a rear end of the exhaust gas introducing pipe 2 and a
front end of the finisher 4 are positioned inside the second inner
pipe 16.
[0039] The valve mechanism 6 is to change a route that the exhaust
gas passes through the casing main body 3 in accordance with
pressure of the exhaust gas from the engine. The valve mechanism 6
is provided on a rear end of the exhaust gas introducing pipe 2 and
constituted of a fixing member 30, a rod member 31, a valve body
32, a valve sheet 33, a spring 34, a spring shoe 35, and a means
for adjusting pressure 36.
[0040] The fixing member 30 is secured on an inner surface of the
exhaust gas introducing pipe 2, has a constitution that the exhaust
gas can pass through and is connected with a front end of the rod
member 31. The spring shoe 35 is secured in the neighborhood of a
rear end of the rod member 31. The valve body 32 is secured
slidably in approximately middle portion of the rod member 31 and
is a approximately conical member with a top portion 37 formed
flatly. The valve sheet 33 is formed on a rear end of the exhaust
gas introducing pipe 2 so as to be in contact with a slant surface
of the valve body 32 airtightly. A front end of the spring 34 is
secured on a rear side surface of the top 37 of the valve body 32
and a rear end thereof is secured on the spring shoe 35.
[0041] According to the muffler 1 with the above mentioned
constitution, when pressure by the exhaust gas from the engine is
smaller than pressure by the spring 34 (and atmospheric pressure),
that is a usual traveling, as shown in FIG. 1A, the valve body 32
is in a closed condition, so that the exhaust gas passes, as shown
by an arrow in FIG. 1A, through a first expansion chamber 40 and
then a first passage 41 defined between the casing main body 3 and
the inner pipe 15, passing through the small holes 22 formed in the
first inner pipe 15 to a second passage 42 defined between the
first inner pipe 15 and the second inner pipe 16, then passing
through a second expansion space 43 to a third passage 44 defined
between the inner pipe 16 and the finisher 44, and then going into
a third expansion space 45 inside the second inner pipe 16. In a
usual traveling exhaust gas route as mentioned above, because the
exhaust gas passes through three expansion spaces 40, 43 and 45, a
sufficient sound deadening effect can be gained.
[0042] On the other hand, when the pressure by the exhaust gas from
the engine is larger than the pressure by the spring 34 (and
atmospheric pressure), that is a high speed traveling, as shown in
FIG. 1B, the valve body 32 moves in an open condition, so that the
exhaust gas goes, as shown by an arrow in FIG. 1B, into the third
expansion space 45 directly. In a high speed exhaust gas route, the
flowing resistance of the exhaust gas is decreased, so that an
output of the engine can be increased.
[0043] As the above, according to the first working mode, at the
usual traveling that the output of the engine is within a usual
range or that an only low power is necessary, the valve body 32 in
the valve mechanism 6 is in a closing position to pass the exhaust
gas through the first, the second and third expansion space 40, 43
and 45, so that the sufficient sound deadening effect can be
gained. On the other hand, at the high speed traveling or high
power traveling such as acceleration, the valve body 32 moves to an
opening position to introduce the exhaust gas to the third
expansion space 45 directly, the output of the engine can be
increased because the flowing resistance of the exhaust gas can be
decreased. Thus, muffler characteristics according to a traveling
condition can be gained. Besides, the muffler 1 can be miniaturized
rather than a constitution that the pipes are arranged in parallel
with one another as a prior art by arranging the first inner pipe
15 and the second inner pipe 16 successively inside the casing main
body 3 and further forming flow passages of the exhaust gas in
spaces defined between them.
[0044] Hereinafter, other working modes are explained by referring
to the drawings, but parts in the other working modes which are
same as or similar to ones in the first working mode are remarked
by same symbols in the first working mode in order to omit
explanation thereof.
[0045] A muffler for a motor vehicle 50 according to a second
working mode as shown in FIGS. 2A and 2B is that the second passage
42 between the first inner pipe 15 and the second inner pipe 16 is
employed as a passage communicating between the first expansion
space 40 and the second expansion space 43, an acoustic material 5
is arranged over a whole surface of the first passage 41 between
the casing main body 3 and the first inner pipe 15.
[0046] An exhaust gas flow route in the second working mode is
constituted of the first expansion space 40, the second passage 42
between the first inner pipe 15 and the second inner pipe 16, the
second expansion space 43, the third passage 44 between the second
inner pipe 16 and the finisher 4, and the third expansion space 45
in turn as shown in FIG. 2A. According to thus constitution, an
area where the exhaust gas is in contact with the acoustic material
5 becomes large, so that the sound deadening effect can be further
increased. Besides, at a high speed traveling, as shown in FIG. 2B,
the exhaust gas goes into the third expansion space 45 directly
from the exhaust gas introducing pipe 2, so that the same effect as
the first working mode can also be gained.
[0047] A muffler for a motor vehicle 60 according to a third
working mode as shown in FIGS. 3A and 3B is that the first passage
41 between the casing main body 3 and the first inner pipe 15 is
employed as a passage communicating between the first expansion
space 40 and the second expansion space 43, the acoustic material 5
is arranged over an approximately whole surface in the second
passage 42 between the first inner pipe 15 and the second inner
pipe 16. Besides, a top portion 61 of the valve body 32 is in a
smooth round shape and a surface backward of the top portion 61 is
provided with a fixing member 62 for fixing an end of the spring
34.
[0048] An flowing route of the exhaust gas according to the third
working mode is constituted of the first expansion space 40, the
first passage 41 between the casing main body 3 and the first inner
pipe 15, the second expansion space 43, the third passage 44
between the second inner pipe 16 and the finisher 4, and the third
expansion space 45 in turn at the usual traveling as shown in FIG.
3A. According to thus constitution, the area where the exhaust gas
is in contact with the acoustic material 5 can be enlarged
similarly to the second working mode, so that the sound deadening
effect can be increased. Besides, the exhaust gas goes from the
exhaust gas introducing pipe 2 to the third expansion space 45
directly at the high speed traveling as shown in FIG. 3B, so that
the same effect as the first and the second working modes can be
gained. Furthermore, the flowing resistance of the exhaust gas can
be decreased by the shape of the top portion 61 of the valve body
32, so that the flowing resistance of the exhaust gas can be
smaller than ones of the first and the second working modes.
[0049] A muffler for a motor vehicle 70 according to a fourth
working mode as shown in FIG. 4 is constituted of at least the
exhaust gas introducing pipe 2 which is connected to the exhaust
side opening of the engine not shown in figures directly or
indirectly, the finisher 4 which is located in a downstream side of
an exhausting direction on an extending line of the exhaust gas
introducing pipe 2, the silencer mechanism 8 provided between the
exhaust gas introducing pipe 2 and the finisher 4, and a valve
mechanism 6 which is provided in a downstream end in the exhaust
direction A of the exhaust gas introducing pipe 2 and communicates
between the exhaust gas introducing pipe 2 and the finisher 4 when
pressure of the exhaust gas exceeds a specific value.
[0050] The muffler 70 further comprises a plurality of small holes
12 formed around an end of the exhaust gas introducing pipe 2 and
neighborhood to the valve mechanism 6; the first inner pipe 15 that
is arranged concentrically to the exhaust gas introducing pipe 2
and that is in a cylindrical shape with an opening in one end
thereof having a downstream side closing bottom surface portion 71
which is secured around the exhaust gas introducing pipe 2 and in a
downstream side of the small holes 12 in the exhaust direction A;
the second inner pipe 16 that is arranged concentrically to the
exhaust gas introducing pipe 2 and that is in a cylindrical shape
with an opening in one end thereof and with a larger radius by a
specific value than one of the first inner pipe 15 having an
upstream side closing bottom surface portion 72 which is secured
around the exhaust gas introducing pipe 2 and in an upstream side
of the small holes 12 in the exhaust direction A; a third inner
pipe 18 which is overlapped at a specific area with the first inner
pipe 15, whose downstream side end portion 73 is connected to the
finisher 4, which is in a cylindrical shape with openings in both
ends thereof having a smaller radius by a specific value than one
of the inner pipe 15; a fourth inner pipe 21 which has a smaller
radius by a specific value than the third inner pipe 18, which is
arranged inside the third inner pipe 18, which has an upstream side
expanding radius portion 75 whose end 74 is secured on an inner
surface 81 of the first inner pipe 15, an downstream side expanding
radius portion 77 whose end 76 is secured on an inner surface 82 of
the finisher 4 and downstream side exhausting holes 17; and the
casing main body 3 provided outside the second inner pipe 16.
[0051] The downstream side expanding radius portion 77 positioned
inside the finisher 4 has, as shown in FIGS. 5A and 5B, the
downstream side exhausting holes 17 arranged at specific intervals
along a circumferential direction of an outer circumferential
surface thereof, the downstream side exhausting holes 17 being
formed in an approximately square shape and formed so as to punch
out to radial directions so that openings 17a thereof are opened to
the third passage 44 side, respectively. Thus, punched out portions
become guide portions 17b, so that the exhaust gas can be
discharged backward of the finisher 4 efficiently.
[0052] According to thus constitution, the silencer mechanism 8 is
constituted of the first expansion space 40 defined by the first
inner pipe 15, the second inner pipe 16, the downstream side
closing bottom surface portion 71 and the upstream side closing
bottom surface portion 72 and communicated to the small holes 12;
the first passage 41 defined by the first inner pipe 15 and the
second inner pipe 16; the second expansion space 43 defined by the
second inner pipe 16 and the casing main body 3 and on which the
first passage 41 is opened; the second passage 42 defined by the
first inner pipe 15 and the third inner pipe 18 and communicating
to the second expansion space 43; the third passage 44 defined by
the third inner pipe 18 and the fourth inner pipe 21 and
communicated between the second passage 42 and the downstream side
exhausting holes 17; and the third expansion space 45 defined
inside the fourth inner pipe 21, to which the downstream side
exhausting holes 17 are opened, communicated to an opening 78 of
the finisher 4, and communicated to the exhaust gas introducing
pipe 2 by an open condition of the valve mechanism 6.
[0053] Thus, when the valve mechanism is in a close condition, the
exhaust gas introduced into the exhaust gas introducing pipe 2 is
flown from the small holes 12 into the first expansion space 40
formed in the upstream side of the first passage 41, wherein a
first expansion is carried out. Then, the exhaust gas is discharged
from the first passage 41 to the second expansion space 43 to carry
out a second expansion, and further a third expansion is carried
out by passing through the second and the third passages 42, 44 and
going into the third expansion space 45 from the downstream aide
exhausting holes 17 and an outside space. Thus, plural times of
expansion can be carried out, so that sound of the exhaust gas is
deadened efficiently.
[0054] Furthermore, the valve mechanism 6 is constituted of a valve
body 51 which opens and closes an end of the exhaust gas
introducing pipe 2 and which is in a convex shape such as to
project to an upstream side of the exhausting direction A, the
spring 52 pressing the valve body 51 to the end of the exhaust gas
introducing pipe 2, a mechanism for adjusting pressure 53 for
adjusting pressure by the spring 52.
[0055] Besides, the mechanism for adjusting pressure 53 is
constituted of a holding portion 54 for holding one end of the
spring 52 and a rotation portion 55 for adjusting the pressure by
moving the holding portion 54 to the valve body 51, wherein the
rotation portion 55 is positioned on an extending line of a center
line of the muffler 70, so that the rotation portion 55 can be
rotated through an opening 78 of the finisher 4 to make it possible
to adjust the pressure. Thus, opening valve pressure of the valve
can be adjusted.
[0056] Concretely, a frame body 57 for fixing a rod 56 on which the
rotation portion 55 is screwed is secured inside the exhaust gas
introducing pipe 2, and the valve body 51 and the holding portion
54 which is cylindrical with bottom surfaces are fit into the rod
56 slidably. Then, the spring 52 is arranged between the valve body
51 and the holding portion 54 and the holding portion 54 is secured
to the rod 56 by a nut as the rotation portion 55.
[0057] In thus constitution, when pressure of the exhaust gas
applying to the valve body 51 exceeds pressure determined by the
spring 52, the valve body 51 is released from the end of the
exhaust gas introducing pipe 2 to make the exhaust gas introducing
pipe 2 and the finisher short-cut via the third expansion space 45,
so that the flowing resistance of the exhaust gas can be
decreased.
[0058] Furthermore, the pressure by the spring 52 is increased by
moving the holding portion 54 so as to bring near to a valve body
51 by rotating the rotation portion (the nut) 55 and is decreased
by moving the holding portion so as to be away from the valve body
51. Thus, the pressure of the spring 52 pressing the valve body 51
can be varied by rotation of the rotation portion (the nut) 55, a
desired opening pressure to the valve body 51 can be gained.
[0059] A muffler for a motor vehicle 80 according to a fifth
working mode is shown in FIG. 6. The muffler 80 is provided with a
fifth inner pipe 23 that is arranged outside the second inner pipe
16 and has a closing bottom portion 83 which closes between the
second passage 42 and the second expansion space 43 and which
connects between the first passage4 41 and the second passage 42,
and that defines a fourth passage 46 communicating between the
first passage 41 and the second expansion space 43 between the
second inner pipe 16 and itself. A junction space 86 to the second
passage 42 and the fourth passage 46 is defined on an outlet side
end of the first passage 41.
[0060] Thus, the muffler 70 according to the fifth working mode is
a resonance tube type such that the second expansion space 43 is a
resonance space.
[0061] Downstream side expanding radius portions 77 as shown in
FIGS. 7A and 7B are characterized in that the downstream side
exhausting holes 17 arranged at specific intervals along a
circumferential direction of the outer circumferential surface
thereof are formed in a streamline shape. Accordingly, parts
embossed outside in a radial direction are worked as guide portions
17a each of which is a streamline shape, so that the exhaust gas
flown from openings 17c opened against the third passage 44 can be
discharged backward of the finisher 4 more efficiently.
[0062] A muffler for a motor vehicle 90 according to a sixth
working mode as shown in FIG. 8 and FIG. 9 is constituted of the
exhaust gas introducing pipe 23 connected to the exhaust side
opening of the engine directly or indirectly, the finisher 4
arranged in a downstream side in the exhaust direction on an
extending line of the exhaust gas introducing pipe 2, the silencer
mechanism 8 provided between the exhaust gas introducing pipe 2 and
the finisher 4 and the valve mechanism 6 short-cutting between the
exhaust gas introducing pipe 2 and the finisher 4.
[0063] The silencer mechanism 8 is constituted of the cylindrical
casing main body 3 constituting an outside frame, the first inner
pipe 15 which is a cylindrical member with a smaller radius than
one of the casing main body 3 and arranged inside the casing main
body 3, the second inner pipe 16 which is a cylindrical member with
a smaller radius than one of the first inner pipe 15 and arranged
inside the first inner pipe 15, and the third inner pipe 18 which
is a cylindrical member with a smaller radius than one of the
second inner pipe 16 and arranged inside the second inner pipe
16.
[0064] The casing main body 3 is that a front end portion 3a
thereof is connected with the exhaust gas introducing pipe 2 via a
front side cover 10 and a rear end portion 3b thereof is connected
with the finisher 4 via a rear side cover 11. The third inner pipe
18 is that a front end portion 18a thereof is connected with a rear
end portion 2a of the exhaust gas introducing pipe 2 and a rear end
portion 18b thereof is connected with a front end portion 6a of the
valve mechanism 6.
[0065] The second inner pipe 16 whose rear end portion 16b is
connected with a front end portion 4a of the finisher 4 is secured
on the third inner pipe 18 by a calking portion 16c formed on an
upstream side portion in the exhaust direction from the rear end
portion 16b thereof.
[0066] The first inner pipe 15 is secured to the third inner pip 18
by a fixing closing member 91 arranged neighborhood to a front end
thereof and secured to the second inner pipe 16 by a calking
portion 15c formed neighborhood to a rear end thereof.
[0067] A front end portion 16a of the second inner pipe 16 is
positioned backward (a little to the finisher 4) from the fixing
closing member 91. Besides, the fixing closing member 91 is a wall
surface shaped member over a whole circumferential edge of the
third inner pipe 18 and closes a space 92 defined between the first
and the third inner pipes 15, 18.
[0068] The calking portions 15c and 16c are formed plurally at
specific intervals along a circumferential direction, so that they
do not prevent the exhaust gas from passing through.
[0069] Besides, the plural small holes 12 are formed in a part
which is a little to the front end 18a of the third pipe 18 from
the fixing closing member 91.
[0070] The valve mechanism 6 is arranged on the rear end portion
18b of the third inner pipe 18, that is to say, just in front of
the finisher 4, and constituted of the fixing member 30, the rod
member 31, the valve body 32, the valve sheet 33, the spring 34,
the spring shoe 35, and a means for adjusting pressure 36.
[0071] The fixing member 30 is secured on the rear end portion 18b
of the third inner pipe 18 and has a shape such that the exhaust
gas can pass through. A front end of the rod member 31 is secured
on the fixing member 30. The spring shoe 35 is secure on a rear end
of the rod member 31. The valve body 32 is an approximately conical
shaped member and is fixed slidably along an axial direction of the
rod member 31. The valve sheet 33 is provided on the rear end
portion of the fixing member 30 and has a shape such that the valve
body 32 can be in contact with it. The spring 34 is that a front
end thereof is fixed on an inner surface portion of the valve body
32 and an rear end thereof is fixed on the spring shoe 35. The
means for adjusting pressure 36 is such that the pressure of the
spring 34 is adjusted by moving a fixing position of the spring
shoe 35 slidably along the rod member 31 and has a constitution
such as to be rotated by a hexagonal wrench and so on.
[0072] According to the muffler 90 with the above constitution,
when pressure of the exhaust gas from the engine is smaller than
pressure of the spring 34 (and atmospheric pressure) (a usual
traveling), as shown in FIG. 8, the valve body 32 is in a closing
condition, so that the exhaust gas flown out of the exhaust gas
introducing pipe 2, as shown by an arrow A, enters into a first
space S1 defined inside the third inner pipe 18, entering a second
space S2 defined by the third inner pipe 18, the first inner pipe
15, the fixing closing member 91 and the front side cover 10 via
the small holes 12, passing through a third space S3 defined
between the casing main body 3 and the first inner pipe 15, passing
through a fourth space S4 defined by the first inner pipe 15 and
the second inner pipe 16, passing through a fifth space S5 defined
between the second inner pipe 16 and the third inner pipe 18, then
discharging to the outside via the finisher 4. Thus, in an exhaust
gas route at the usual traveling, the exhaust gas passes through a
complicated pulsation decreasing passage constituted of the spaces
S1, S2, S3, S4 and S5, so that the pulsation can be decreased
sufficiently.
[0073] Besides, the second space S2 and the third space S3
constitute the first expansion space, the fourth space S4 and the
fifth space S5 constitute the first passage, and the space inside
the finisher 4 constitutes the second expansion space.
[0074] On the other hand, when the pressure of the exhaust gas from
the engine is larger than the pressure of the spring 34 (and
atmospheric pressure) (a high-power traveling), as shown in FIG. 9,
the valve body 32 moves to an opening condition, so that the
exhaust gas goes from the first space S1 to the finisher 4 directly
as shown by an arrow A'. Thus, the resistance of exhausting is
decreased, so that the output of the engine is increased.
[0075] Furthermore, the valve mechanism 6 is provided on the
downstream side end portion of the third inner pipe 18 that is just
in front of the finisher 4, so that the exhaust gas flown out of
the exhaust gas introducing pipe 2 rushes into the first space S1
in spite of the opening or closing condition of the valve mechanism
6 and then discharges to the second space S2 via the small holes
12, so that the first space S1 can be employed as a resonance
space. Thus, performance of sound deadening can be increased.
INDUSTRIAL APPLICABILITY
[0076] As the above, according to the present invention, because
the inner pipes are provided inside the casing main body in turn
and spaces defined between them are employed as a flow passage of
the exhaust gas, miniaturization of the muffler can be achieved as
the performance thereof is maintained.
[0077] Besides, when the pressure of the exhaust gas from the
engine becomes more than a specific value, the valve mechanism is
in the open condition for the exhaust gas to flow into the finisher
directly. Thus, the resistance of exhausting is decreased, so that
the muffler characteristics corresponding to the traveling
condition can be gained and the output of the engine can be
increased.
[0078] Furthermore, in the case that the valve mechanism is
provided just in front of the finisher, the exhaust gas flown out
of the exhaust gas introducing pipe rushes into an upstream side
space of the valve in the closing condition of the valve mechanism
and flows into the first expansion space via the small holes, so
that the upstream side space is employed as a resonance space to
constitute a resonance tube type of a silencer mechanism, as a
result, the sound deadening performance can be increased.
[0079] Moreover, the valve mechanism is provided in a position
facing to the opening of the finisher which is an end portion of
the exhaust gas introducing pipe, so that pressure for opening
valve can be adjusted easily from the opening of the finisher.
* * * * *