U.S. patent application number 11/816792 was filed with the patent office on 2009-02-26 for exhaust heat recovery device.
Invention is credited to Shuichi Hase.
Application Number | 20090049832 11/816792 |
Document ID | / |
Family ID | 36927363 |
Filed Date | 2009-02-26 |
United States Patent
Application |
20090049832 |
Kind Code |
A1 |
Hase; Shuichi |
February 26, 2009 |
EXHAUST HEAT RECOVERY DEVICE
Abstract
An exhaust heat recovery device provided in an exhaust system of
an engine etc., having a heat exchanger for performing heat
exchange between exhaust gas and a medium, a bypass route through
which the exhaust gas bypasses the heat exchanger, and a valve body
for opening and closing the bypass route, wherein wiring and piping
are reduced to make the device advantageous in cost. The exhaust
heat recovery device has a valve body that, when the flow rate of
the exhaust gas is equal to or higher than a predetermined value,
opens the bypass route from a closed state against urging force of
an urging body. The exhaust heat recovery device also has a
temperature-activated actuator that opens the valve body when the
temperature of the medium is equal to or higher than a
predetermined value. The construction causes the valve body to be
opened when at least either of the flow rate of the exhaust gas and
the temperature of the medium is equal to or higher than the
predetermined value.
Inventors: |
Hase; Shuichi; (Miyoshi,
JP) |
Correspondence
Address: |
Dickinson Wright PLLC;James E. Ledbetter, Esq.
International Square, 1875 Eye Street, NW., Suite 1200
WASHINGTON
DC
20006
US
|
Family ID: |
36927363 |
Appl. No.: |
11/816792 |
Filed: |
February 22, 2006 |
PCT Filed: |
February 22, 2006 |
PCT NO: |
PCT/JP2006/303135 |
371 Date: |
August 21, 2007 |
Current U.S.
Class: |
60/320 |
Current CPC
Class: |
F01N 5/02 20130101; F01N
2410/02 20130101; Y02T 10/12 20130101; F01N 2410/14 20130101; F01N
2240/36 20130101; Y02T 10/16 20130101; F01N 2240/02 20130101 |
Class at
Publication: |
60/320 |
International
Class: |
F01N 5/00 20060101
F01N005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2005 |
JP |
2005-087052 |
Claims
1. An exhaust heat recovery device provided in an exhaust system of
an internal combustion engine or the like and comprising a heat
exchanger for performing heat exchange between exhaust gas and a
medium, a bypass route through which the exhaust gas bypasses the
heat exchanger, and a valve body for opening and closing the bypass
route, wherein said exhaust heat recovery device further comprises
a valve body that operates to open said bypass route from a closed
state against urging force of an urging member when a flow rate of
the exhaust gas is equal to or higher than a predetermined value,
and a temperature-activated actuator that causes said valve body to
open when the temperature of said medium is equal to or higher than
a predetermined value, whereby said valve body operates to open
when at least one of the flow rate of the exhaust gas and the
temperature of the medium is equal to or higher than the
corresponding predetermined value.
2. The exhaust heat recovery device according to claim 1, further
comprising a crank mechanism that causes said valve body to open by
an expanding movement of said temperature-activated actuator which
expands and contracts according to the temperature of said medium,
and a floating mechanism that couples the contracting movement of
said temperature-activated actuator and the closing movement of
said valve body in an floating state.
3. The exhaust heat recovery device according to claim 1, wherein
said temperature-activated actuator is a thermoelement which
expands and contracts by an incorporated wax.
4. The exhaust heat recovery device according to claim 2, wherein
said temperature-activated actuator is a thermoelement which
expands and contracts by an incorporated wax.
Description
TECHNICAL FIELD
[0001] The present invention relates to an exhaust heat recovery
device provided in an exhaust system of a vehicle equipped with an
internal combustion engine and recovering exhaust heat to use it
for warm-up etc.
BACKGROUND ART
[0002] There has been known such an exhaust heat recovery device
which opens and closes a valve body of an exhaust system according
to the driving state of an internal combustion engine and the
temperature of a medium (cooling water) and can perform switching
control of the passage of exhaust gas between a heat exchanger in
the exhaust system and a bypass route through which the exhaust gas
bypasses the heat exchanger. By controlling in this manner, an
exhaust heat recovery device described in Patent Document 1, for
example, is intended to eliminate the defect of the driving
performance in the cold state of a vehicle.
[0003] Patent Document 1: JP-U-63-160315
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] The exhaust heat recovery device described in the
above-mentioned Patent Document 1 requires driving means such as a
motor and a power driving actuator for driving a valve body used
for switching control in the valve, control means such as a
computer for controlling the same, and detecting means for
detecting the rotational speed of the internal combustion engine
and the temperature of the medium. Wiring and piping are required
for connecting them and a dedicated design is required for each
vehicle This cannot be an advantageous method in cost.
Means for Solving the Problems
[0005] To solve the above problems, the invention according to
claim 1 is an exhaust heat recovery device provided in an exhaust
system of an internal combustion engine and comprising a heat
exchanger for performing heat exchange between exhaust gas and a
medium, a bypass route through which the exhaust gas bypasses the
heat exchanger, and a valve body for opening and closing the bypass
route, wherein the exhaust heat recovery device comprises the valve
body that operates to open the bypass route from a closed state
against urging force of an urging member when the flow rate of the
exhaust gas is equal to or higher than a predetermined value, and a
temperature-activated actuator that causes the valve body to open
when the temperature of the medium is equal to or higher than a
predetermined value, whereby the valve body operates to open when
at least one of the flow rate of the exhaust gas and the
temperature of the medium is equal to or higher than the
corresponding predetermined value.
[0006] The invention according to claim 2, in the invention
according to claim 1, is an exhaust heat recovery device further
including a crank mechanism that causes the valve body to open by
an expanding movement of the temperature-activated actuator which
expands and contracts according to the temperature of the medium,
and a floating mechanism that couples the contracting movement of
the temperature-activated actuator and the closing movement of the
valve body in a floating state.
[0007] The invention according to claim 3, in the invention
according to claim 1 or 2, is an exhaust heat recovery device
wherein the temperature-activated actuator is a thermoelement which
expands and contracts by an incorporated wax.
EFFECT OF THE INVENTION
[0008] According to the present invention, when the flow rate of
the exhaust gas is increased to be equal to or higher than the
predetermined value, the valve body is opened so as to open the
bypass route regardless of the temperature of the medium and the
exhaust gas thus flows through the bypass route, bypassing the heat
exchanger on the exhaust system, and accordingly, the flow
resistance of the exhaust gas in the exhaust system can be reduced.
It is therefore possible to eliminate the disadvantage of the
driving performance when the vehicle is started in the insufficient
warmed state. Further, also in the state where the flow rate of the
exhaust gas is low and the bypass route is closed by the valve
body, if the temperature of the medium is equal to or higher than
the predetermined value, the temperature-activated actuator causes
the valve body to open so as to open the bypass route, and the
exhaust gas then bypasses the heat exchanger so as to flow through
the bypass route, and accordingly, it is possible to suppress
overheat of the medium flowing through the heat exchanger.
Therefore, the overload on a cooling system of a vehicle concerned
in a traffic jam can be prevented.
[0009] Also, the control of this exhaust heat recovery device is
completed in the exhaust heat recovery device, and none of wiring,
piping, detecting means, control means and power supply are
required, thus, the present invention is excellent in mounting
ability, economy effect, and reliability.
BEST MODE FOR CARRYING OUT THE INVENTION
[0010] Best mode for carrying out the present invention will be
described on the basis of embodiments shown in FIGS. 1 to 8C.
Embodiment 1
[0011] FIGS. 1 to 3 show Embodiment 1 according to the present
invention, in which FIG. 1 is a front view showing an exhaust heat
recovery device 1 of Embodiment 1, FIG. 2 is a vertical section
view of the exhaust heat recovery device 1 in FIG. 1, and FIG. 3 is
a cross-sectional view taken along line III-III in FIG. 1.
[0012] The exhaust heat recovery device 1 is disposed in an exhaust
system of a vehicle, etc., having an internal combustion engine; an
upstream side exhaust pipe J is connected to the upstream side of
the device 1 (on a left side in the drawing) and a downstream side
exhaust pipe K is connected to the downstream side of the device 1
(on a right side in the drawing), as shown in FIG. 1. A
funnel-shaped cone 2 and one end of a first case 3 having a
cylindrical shape, and the other end of the first case 3 and a
second case 4 having a tubular shape are joined to each other so as
to sandwich retainers 5 and 6 therebetween, respectively.
[0013] A cover pipe 13 is provided inside the first case 3
substantially coaxially with the first case 3 and through both the
retainers 5 and 6 in a liquid-tight manner, as shown in FIGS. 2 and
3, and the first case 3, the cover pipe 13, and both the retainers
5 and 6 form a medium flow part 14. A medium inlet 16 and a medium
outlet 15 which are connected to a cooling system of the internal
combustion engine are provided in the first case 3 so that a medium
flows through the medium flow part 14. Heat exchange pipes 17
having helical grooves formed therein are arranged in the medium
flow part 14, extending through both the retainers 5 and 6, a
plurality of the heat exchange pipes 17 are disposed so as to
surround the outer circumference of the cover pipe 13, as shown in
FIG. 3, and the heat exchange is performed between the medium
flowing through the medium flow part 14 and the exhaust gas when
exhaust gas flows through the heat exchange pipes 17. In Embodiment
1, the first case 3, the retainers 5 and 6, the cover pipe 13, the
medium flow part 14, the medium inlet 16, the medium outlet 15, and
the heat exchange pipes 17 constitute a heat exchanger.
[0014] Outside the first case 3, there are provided a thermoelement
7 as a temperature-activated actuator, and an element cover 8
covering the same. The element cover 8 is constructed such that the
medium flowing through the medium flow part 14 can flow in the
inside of the element cover 8 so that the thermoelement 7 and the
medium can contact with each other. The thermoelement 7 causes an
activating arm 12 to perform a translatory expanding motion in the
.beta. direction, according to the heat expansion of the
incorporated paraffin wax corresponding to a temperature rise of
the flowing medium, and allows the activating arm 12 to perform a
translatory contracting motion in the opposite direction to the
above-mentioned direction by a return spring 9 disposed in the
thermoelement 7 when the temperature of the medium is lowered and
the paraffin wax contracts. The activating arm 12 has at its end an
axially extending slot 26 and a rod 25 having a pin 27 engaging
with the slot 26 can slide axially within the range of the slot 26,
so as to form a floating mechanism.
[0015] A bypass pipe 18 forming a bypass route is disposed inside
the cover pipe 13 substantially coaxially with the cover pipe 13.
The bypass pipe 18 is formed by a cylindrical pipe having upstream
and downstream open ends, joined to the downstream end of the cover
pipe 13, and held onto the upstream end of the cover pipe 13 via a
sliding member 19. This can absorb a heat expansion difference
between the cover pipe 13 and the bypass pipe 18 caused when the
exhaust gas flows through the bypass pipe 18, thereby improving
durability.
[0016] As shown in FIG. 2, a valve seat 20 and a cushioning member
21 suppressing any hitting noise are provided at the downstream end
of the bypass pipe 18. A butterfly valve body 22 which contacts
with the valve seat 20 and can open and close the bypass pipe 18 is
rotatably provided on a valve shaft 10 disposed at a periphery near
the end of the bypass pipe 18, and is urged in the closing
direction of the bypass pipe 18 by an urging spring, not shown.
When the flow rate of the exhaust gas flowing through the bypass
pipe 18 is equal to or lower than a predetermined value, the valve
body 22 closes the downstream end of the bypass pipe 18 by the
urging force of the urging spring. The valve system opening and
closing according to the flow rate of the exhaust gas is known in
the exhaust devices as a variable valve.
[0017] One end of the valve shaft 10 protrudes outside the second
case 4, one end of a crank 11 is integrally journaled to the
protruding end of the valve shaft 10, and the rod 25 of the
above-described floating mechanism is journaled to the other end of
the crank 11 via a pivot 24. The valve body 22 is rotated via the
crank mechanism by the expansion and contraction of the
thermoelement 7.
[0018] The operation of the thus-constituted exhaust heat recovery
device 1 of Embodiment 1 will be described.
[0019] When the flow rate of the exhaust gas and the temperature of
the medium are equal to or lower than the respectively
predetermined values, the valve body 22 closes the bypass pipe 18
by the urging force of the urging spring, not shown. The exhaust
gas forcibly flows through in the heat exchange pipes 17 to be
heat-exchanged between the exhaust gas and the medium flowing
through the medium flow part 14.
[0020] When the flow rate of the exhaust gas is equal to or higher
than the predetermined value, even if the temperature of the medium
is equal to or lower than the predetermined value, the exhaust gas
rotates the valve body 22 in the .alpha. direction shown in FIG. 2.
The rod 25 is moved in the .beta. direction shown in FIG. 1,
accompanying the rotation of the crank 11 provided integrally with
the valve body 22, but the valve body 22 can be rotated without
being affected by the thermoelement 7 to open the bypass pipe 18
since the rod 25 is coupled to the activating arm 12 in the
floating manner.
[0021] When the temperature of the medium is equal to or higher
than the predetermined value, even if the flow rate of the exhaust
gas is equal to or lower than the predetermined value, the
thermoelement 7 expands to move the activating arm 12 in the .beta.
direction and the left end of the slot 26 in the drawing is engaged
with the pin 27 to move the rod 25 in the .beta. direction. Along
with it, the rotation of the crank 11 about the valve shaft 10
causes the valve body 22 integral therewith to rotate in the
.alpha. direction and in the opening direction to open the bypass
pipe 18.
[0022] In Embodiment 1, when the flow rate of the exhaust gas is
increased to be equal to or higher than the predetermined value,
the bypass pipe 18 is opened regardless of the temperature of the
medium and the exhaust gas then bypasses the heat exchange pipes 17
to flow through the bypass pipe 18. Thus, the flow resistance of
the exhaust gas can be reduced, and accordingly, it is possible to
eliminate the disadvantage of the driving performance when a
vehicle is started in the state that warm-up is insufficient. On
the other hand, even in the state that the flow rate of the exhaust
gas is low and the bypass pipe 18 is closed by the valve body 22,
when the temperature of the medium is equal to or higher than the
predetermined value, the thermoelement 7 as the
temperature-activated actuator causes the valve body 22 to open,
and the exhaust gas bypasses the heat exchange pipes 17 to flow
through the bypass pipe 18, whereby the overheat of the medium can
be prevented. Therefore, concerns of the overload on a cooling
system of a vehicle equipped with an internal combustion engine in
a traffic jam can be prevented.
Embodiment 2
[0023] FIG. 4 is a schematic view showing an exhaust heat recovery
device 31 of Embodiment 2 according to the present invention.
[0024] The heat recovery device 31 is disposed in an exhaust system
of a vehicle, etc., having an internal combustion engine; an
upstream side exhaust pipe (not shown) is connected to the upstream
side of the device (left side in the drawing) and a downstream side
exhaust pipe (not shown) is connected to the downstream side of the
device (right side in the drawing). A heat exchanger 32 is
connected to a cooling system of the internal combustion engine,
not shown, by a medium outlet 32a and a medium inlet 32b and
constructed such that it can perform heat exchange between the
exhaust gas and a medium flowing through the heat exchanger 32. A
bypass route 33 is provided to lead the exhaust gas to the
downstream side exhaust pipe by bypassing the heat exchanger 32. On
the way of the bypass route 33, a butterfly valve body 35 is
provided on a valve shaft 36, being urged in the direction closing
the bypass route 33 by an urging member 34 constituted by a spring,
and the valve body 35 can rotate conjointly with the valve shaft 36
around the valve shaft 36. When the flow rate of the exhaust gas is
equal to or higher than the predetermined value, the valve body 35
is rotated against the urging force of the urging member 34 to open
the bypass route 33.
[0025] A thermoelement 37 as the temperature-activated actuator is
provided outside the heat exchanger 32 in such a manner that its
heat receiving portion is brought into contact with the medium
flowing through the heat exchanger 32. The thermoelement 37 causes
a first arm 38a constituting an activating arm 38 to perform a
translatory expanding motion in the .beta. direction in FIG. 4,
according to the heat expansion of the incorporated paraffin wax
corresponding to temperature rise of the medium, and allows the
first arm 38a of the activating arm 38 to perform a translatory
contracting motion in the opposite direction to the above-mentioned
direction by an incorporated return spring (not shown) when the
paraffin wax is contracted. The free end of the first arm 38a is
rotatably coupled to a second arm 38c by a rotational shaft 38b. In
addition, a crank 39 operatively coupling the activating arm 38
with the valve body 35 is provided for conjoint rotation with the
valve shaft 36. In addition, as shown in FIG. 4, the crank 39 is
formed in a substantially triangular shape around the valve shaft
36 and is provided with an arc slot 39a around the valve shaft 36.
A pin 38d provided at the free end of the second arm 38c of the
activating arm 38 is loosely fitted in the arc slot 39a to be
slidable within the range of the arc slot 39a for forming the
floating mechanism.
[0026] The operation of the thus-constituted exhaust heat recovery
device 31 of Embodiment 2 will be described.
[0027] When the flow rate of the exhaust gas and the temperature of
the medium are both equal to or lower than the respectively
predetermined values, the valve body 35 closes the bypass pipe 33
by the urging force of the urging member 34. The exhaust gas
forcefully flows through the heat exchanger 32 to be heat-exchanged
between the exhaust gas and the medium.
[0028] When the flow rate of the exhaust gas is equal to or higher
than the predetermined value, even if the temperature of the medium
is equal to or lower than the predetermined value, the exhaust gas
rotates the valve body 35 in the .alpha. direction shown in FIG. 4.
The crank 39 is rotated in the counterclockwise direction in FIG. 4
with the rotation of the valve body 35. The pin 38d of the
activating arm 38 is slid in the slot 39a. The valve body 35 is
rotated without being affected by the thermoelement 37 to open the
bypass pipe 33.
[0029] Even if the flow rate of the exhaust gas is equal to or
lower than the predetermined value, when the temperature of the
medium is equal to or higher than the predetermined value, the
thermoelement 37 expands to move the first arm 38a of the
activating arm 38 in the .beta. direction. The pin 38d at the free
end of the second arm 38c presses the lower end of the slot 39a in
the drawing downwardly to rotate the crank 39 in the
counterclockwise direction. At the rotation, the second arm 38c is
rotated around the rotational shaft 38b to the right side in the
drawing and rotates the crank 39 without any trouble. The valve
body 35 is rotated in the opening direction by the rotation of the
crank 39 in the counterclockwise direction to open the bypass pipe
33.
[0030] Embodiment 2 can exhibit the same effect as Embodiment
1.
Embodiment 3
[0031] FIGS. 5 to 8 show Embodiment 3 according to the present
invention, in which FIG. 5 is a front view showing an exhaust heat
recovery device 101 of Embodiment 3, FIG. 6 is a vertical section
view showing the exhaust heat recovery device 101 of Embodiment 3,
taken along line VI-VI in FIG. 5, FIG. 7 is a cross-sectional view
taken along line VII-VII in FIG. 5, and FIGS. 8A to 8C are
partially enlarged views showing operational states as seen in the
D direction in FIG. 5.
[0032] The exhaust heat recovery device 101 is disposed in an
exhaust system of a vehicle, etc., having an internal combustion
engine. As shown in FIG. 5, an upstream side exhaust pipe J is
connected to the upstream side of the device (the left side in the
drawing) and a downstream side exhaust pipe K is connected to the
downstream side (the right side in the drawing) of the device.
[0033] A first case 103 having a cylindrical shape is arranged on
the upstream side of the exhaust heat recovery device 101. As shown
in FIG. 6, a heat exchange pipe 117 is provided inside the first
case 103 substantially coaxially with the first case 103 and in a
liquid-tight manner at both ends of the first case 103, and a
medium flow part 114 is formed between the heat exchange pipe 117
and the first case 103. As shown in FIG. 7, the cross section of
the heat exchange pipe 117 of this embodiment in the direction
orthogonal to its axial direction is formed in a wavy shape
alternately forming four mountain portions 117a and four valley
portions 117b in the circumference direction. The four valley
portions (groove portions) 117b are helically formed in the axial
direction.
[0034] A medium outlet 115 connected to a cooling system of the
internal combustion engine is provided in the first case 103. A
medium inlet 116 is provided in a later-described element cover 108
disposed outside the first case 103. A medium flows through the
medium flow part 114 and in the element cover 108. In Embodiment 3,
the first case 103, the medium flow part 114, the medium outlet
115, the medium inlet 116, the heat exchange pipe 117, and a space
118c constitute a heat exchanger.
[0035] On the downstream side of the heat exchange pipe 117, a
second case 104 including two portions divided in the circumference
direction is joined to the heat exchange pipe 117 so as to sandwich
therebetween a retainer 106 having an opening, not shown.
[0036] A bypass pipe 118 forming a bypass route therein is formed
by two pipes including an upstream side bypass pipe 118a and a
downstream side bypass pipe 118b connected by fitting one in
another via a sliding member 119, the upstream end and the
downstream end of the bypass pipe 118 are opened, and the bypass
pipe 118 is retained inside the heat exchange pipe 117
substantially coaxially with the first case 103 by the upstream
side end of the heat exchange pipe 117 and the retainer 106
provided on the downstream side of the heat exchange pipe 117.
[0037] Near the upstream end of the bypass pipe 118, a plurality of
small-diameter communication holes 126 are formed to be
communicated with the space 118c formed between the bypass pipe 118
and the heat exchange pipe 117. Exhaust gas in the bypass pipe 118
can flow into the space 118c through the communication holes 126.
Upon the flow of the exhaust gas, heat exchange is performed
between the medium flowing through the medium flow part 114 and the
exhaust gas.
[0038] In the downstream portion of the bypass pipe 118, a
butterfly valve body 122 opening and closing the bypass pipe 118 is
provided integrally with a valve shaft 110 pivotally mounted to the
bypass pipe 118, and is urged in the closing direction by an urging
spring 125 urging the rotation of the valve shaft in the fixed
direction. A cushioning member 121 suppressing any hitting noise of
the valve body 122 onto the bypass pipe 118 is provided at the
downstream end of the bypass pipe 118.
[0039] With this constitution, when the flow rate of the exhaust
gas flowing through the bypass pipe 118 is equal to or lower than
the predetermined value, the valve body 122 is urged by the urging
spring 125 to close the downstream end of the bypass pipe 118. When
the flow rate of the exhaust gas is equal to or higher than the
predetermined value, the valve body 122 is opened against the
urging force of the urging spring 125.
[0040] As shown in FIG. 5, the element cover 108 provided with a
thermoelement 107 as the above-described temperature-activated
actuator is disposed outside the first case 103. The medium
circulating through the cooling portion of the internal combustion
engine flows into the element cover 108 through the medium inlet
116.
[0041] The thermoelement 107 is arranged in such a manner that its
heat receiving portion contacts the medium flowing through the
element cover 108, and corresponding to the temperature of the
medium, the thermoelement 107 causes the activating arm 112 to
perform a translatory expanding motion in the .beta. direction in
FIG. 5, according to the heat expansion of the incorporated
paraffin wax when the temperature is high, and allows the
activating arm 112 to perform a translatory contracting motion in
the opposite direction to the above-mentioned direction by a return
spring (not shown) when the temperature is low and the paraffin wax
contracts.
[0042] A crank 111 is provided integrally with the valve shaft 110
for conjoint movement with the valve body 122, an engaging strip
111a formed on the crank 111 is arranged to face the activating arm
112, and the crank 111 opening and closing the valve body 122 by
expanding and contracting the activating arm 112 is provided to be
rotated integrally with the valve shaft 110.
[0043] The activating arm 112 and the crank 111 are not joined to
each other, can contact with each other, and can be spaced from
each other, thereby forming the floating mechanism.
[0044] The operation of Embodiment 3 will be described.
[0045] FIGS. 8A to 8C are partially enlarged views showing
operational states as seen from the D direction in FIG. 5.
[0046] FIG. 8A shows a case where the flow rate of the exhaust gas
and the temperature of the medium are both equal to or lower than
the predetermined value. In this case, the valve body 122 closes
the bypass pipe 118 according to the urging force of the urging
spring 125. The thermoelement 107 is also in the contracted state,
and the activating arm 112 is spaced from the engaging strip 111a
of the crank 111.
[0047] FIG. 8B shows a case where the flow rate of the exhaust gas
is equal to or higher than the predetermined value and the
temperature of the medium is equal to or lower than the
predetermined value.
[0048] In this case, the thermoelement 107 is in the contracted
state, but the flow of the exhaust gas pushes the valve body 122 to
open the bypass pipe 118 against the urging force of the urging
spring 125. At this time, since the crank 111 rotated integrally
with the valve body 122 is provided so that it can be spaced from
the activating arm 112, the valve body 122 is rotated in the
opening direction to open the bypass pipe 18 even if the
thermoelement 107 does not operates and the activating arm 112 does
not expand.
[0049] FIG. 8C shows a case where the temperature of the medium is
equal to or higher than the predetermined value and the flow rate
of the exhaust gas is equal to or lower than the predetermined
value.
[0050] In this case, the thermoelement 107 expands so that the
activating arm 112 is brought into contact with the engaging strip
111a of the crank 111 to push it to thereby rotate the crank 111.
Thus, the valve body 122 rotated integrally with the crank 111 is
rotated in the opening direction to open the bypass pipe 18.
[0051] Embodiment 3 can exhibit the same effect as Embodiment
1.
[0052] The embodiments according to the present invention are
described above, but the present invention is not limited to the
above embodiments, and design changes in the scope without
departing from the purport of the present invention are included in
the present invention.
[0053] For example, the urging member of the valve body may serve
as the urging member (return spring) included in the
thermoelement.
[0054] A bimetal or a shape-memory alloy is used for the
temperature-activated actuator. The valve body may be rotated by
shape change of these.
[0055] A heat exchanger, a valve body, an urging member, a crank
mechanism, and a floating mechanism of conventionally known
constitution can be optionally employed.
[0056] A sound absorbing material may be provided in the bypass
route and the heat exchange route to provide a noise suppressing
function to the heat recovery device.
[0057] The present invention is not limited to a heat recovery
device (heat collector, oil warmer, and the like) in a narrow sense
mainly for heat recovery of a medium, and includes a heat exchanger
(exhaust cooler, EGR cooler, and the like) mainly for cooling
exhaust gas as a heat recovery device. The present invention is
riot limited for being applied to an internal combustion engine of
a vehicle and can be applied to exhaust systems of all exhaust gas
generators such as a general-purpose engine and a stationary type
combustor.
BRIEF DESCRIPTION OF DRAWINGS
[0058] FIG. 1 is a front view showing an exhaust heat recovery
device of Embodiment 1 according to the present invention;
[0059] FIG. 2 is a vertical section view of the exhaust heat
recovery device in FIG. 1;
[0060] FIG. 3 is a cross-sectional view taken along line III-III in
FIG. 1;
[0061] FIG. 4 is a schematic view showing an exhaust heat recovery
device of Embodiment 2 according to the present invention;
[0062] FIG. 5 is a front view showing an exhaust heat recovery
device of Embodiment 3 according to the present invention;
[0063] FIG. 6 is a vertical section view of the exhaust heat
recovery device taken along line VI-VI in FIG. 5;
[0064] FIG. 7 is a cross-sectional view taken along line VII-VII in
FIG. 5;
[0065] FIG. 8A is a partially enlarged view showing an operated
state as seen in the D direction in FIG. 5;
[0066] FIG. 8B is a partially enlarged view showing another
operated state as seen in the D direction in FIG. 5; and
[0067] FIG. 8C is a partially enlarged view showing a further
operated state as seen in the D direction in FIG. 5.
* * * * *