U.S. patent application number 13/365457 was filed with the patent office on 2013-08-08 for heat storage device for an engine.
This patent application is currently assigned to Ford Global Technologies, LLC. The applicant listed for this patent is Danrich Henry Demitroff, Michael Levin, Donald Masch, James Patrick O'Neill, Furqan Zafar Shaikh. Invention is credited to Danrich Henry Demitroff, Michael Levin, Donald Masch, James Patrick O'Neill, Furqan Zafar Shaikh.
Application Number | 20130199751 13/365457 |
Document ID | / |
Family ID | 48794766 |
Filed Date | 2013-08-08 |
United States Patent
Application |
20130199751 |
Kind Code |
A1 |
Levin; Michael ; et
al. |
August 8, 2013 |
HEAT STORAGE DEVICE FOR AN ENGINE
Abstract
A heat recovery system for an engine is disclosed herein
utilizing a heat storage unit configured to store waste exhaust
heat for subsequent use on engine starts in various systems. In
this way, improved system operation can be obtained by re-using
such waste heat.
Inventors: |
Levin; Michael; (Ann Arbor,
MI) ; Shaikh; Furqan Zafar; (Troy, MI) ;
O'Neill; James Patrick; (Milford, MI) ; Masch;
Donald; (White Lake, MI) ; Demitroff; Danrich
Henry; (Okemos, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Levin; Michael
Shaikh; Furqan Zafar
O'Neill; James Patrick
Masch; Donald
Demitroff; Danrich Henry |
Ann Arbor
Troy
Milford
White Lake
Okemos |
MI
MI
MI
MI
MI |
US
US
US
US
US |
|
|
Assignee: |
Ford Global Technologies,
LLC
Dearborn
MI
|
Family ID: |
48794766 |
Appl. No.: |
13/365457 |
Filed: |
February 3, 2012 |
Current U.S.
Class: |
165/10 |
Current CPC
Class: |
Y02T 10/16 20130101;
Y02T 10/12 20130101; F28D 21/0003 20130101; B60H 1/20 20130101;
F02G 5/02 20130101; F28D 20/02 20130101; F28D 20/028 20130101; Y02E
60/145 20130101; F01N 5/02 20130101; Y02E 60/14 20130101; B60H
1/00492 20130101; Y02T 10/166 20130101; F28D 20/023 20130101; F28F
2250/06 20130101; F01N 2240/02 20130101 |
Class at
Publication: |
165/10 |
International
Class: |
F28D 19/00 20060101
F28D019/00 |
Claims
1. A heat storage device for an engine, comprising: an inlet
passage thermally coupling the heat storage device to an exhaust
passage; a stack of phase changing materials positioned radially
about a central feed passage, the stack positioned within an
interior of a double wall vessel; and an outlet passage thermally
coupling the heat storage device to another engine system.
2. The device of claim 1, wherein the inlet passage is coupled to
an end of the heat storage device at a centrally located
position.
3. The device of claim 1, wherein the outlet passage is coupled to
another opposite end of the heat storage device, the outlet passage
at a top periphery located position.
4. The device of claim 1, further comprising a vacuum passage in
fluidic communication with a vacuum space of the double wall
vessel.
5. The device of claim 4, wherein the double wall includes outer
walls and inner walls, and wherein a vacuum jacket is positioned
between the outer walls and the inner walls.
6. The device of claim 5, wherein the inlet passage and the outlet
passage include outer walls, inner walls, and a vacuum space
between the outer walls and the inner walls, the vacuum space in
fluidic communication with the vacuum jacket.
7. A system for an engine, comprising: a heat exchanger in fluidic
communication with an exhaust passage; a heat storage device
including a phase changing material; a first pipe thermally
coupling the heat exchanger to the heat storage device; and a
second pipe thermally coupling the heat storage device to another
engine system.
8. The system of claim 7, wherein the first and second heat pipes
include a phase changing material.
9. The system of claim 7, wherein the phase changing material of
the heat storage device is positioned radially about a central feed
passage.
10. The system of claim 7, wherein the heat storage device includes
more than one phase changing material, each phase changing material
having a different phase transfer temperature.
11. The system of claim 7, wherein the heat storage device is a
double walled vessel including an inner vessel and an outer vessel
separated by a vacuum jacket.
12. The system of claim 11, further comprising a plurality of
anti-radiation foils positioned within the vacuum jacket.
13. The system of claim 12, further comprising a vacuum passage
fluidically coupling the vacuum jacket to a vacuum pump.
14. The system of claim 7, wherein the heat storage device is
tilted 5 degrees from a horizontal, wherein the another system is
separate from the heat exchanger and the heat storage device,
wherein only the second heat pipe couples the another system to the
heat storage device, wherein the another system includes a fluid
conduit separate from the second heat pipe, wherein the fluid
conduit is in thermal contact with the second heat pipe at a
position coinciding with another heat exchanger, wherein the
another heat exchanger is a location where heat transfer occurs
between the second heat pipe and the fluid conduit, and wherein the
another system is selected from the group consisting of a cabin
heating system, a coolant system, and a transmission system.
15. A heat transfer system for an engine, comprising: a heat
exchanger coupled to an exhaust passage downstream from a catalytic
converter; a heat storage device, coupled to the heat exchanger via
an inlet, including a cylindrical stack positioned between two
retention plates; and an outlet coupling the heat storage device to
another engine system.
16. The heat transfer system of claim 15, wherein the heat storage
device is a double walled vessel including inner walls, outer
walls, and a vacuum jacket between the inner and outer walls.
17. The heat transfer system of claim 16, wherein the stack
circumferentially surrounds a central feed passage that supplies a
heat transfer fluid to the heat storage device.
18. The heat transfer system of claim 17, further comprising one or
more springs coupled to one retention plate and the inner walls of
the double walled vessel.
19. The heat transfer system of claim 16, wherein the inlet and the
outlet include double walls with a vacuum space between inner and
outer walls, and wherein the vacuum space is continuous with the
vacuum jacket.
Description
BACKGROUND AND SUMMARY
[0001] Vehicles may recover exhaust heat for transfer to various
other systems in an internal combustion engine.
[0002] The inventors herein have recognized various issues with
such systems in that the available packaging space for storing
waste heat is limited, and further suitable coordination among
various vehicle components is lacking. As such, one example
approach to address the above issues is, claim 1.
[0003] It should be understood that the summary above is provided
to introduce in simplified form a selection of concepts that are
further described in the detailed description. It is not meant to
identify key or essential features of the claimed subject matter,
the scope of which is defined uniquely by the claims that follow
the detailed description. Furthermore, the claimed subject matter
is not limited to implementations that solve any disadvantages
noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIGS. 1A-1B schematically show an example heat storage
device that may be included in an exhaust system.
[0005] FIG. 1C schematically shows an example heat exchanger that
may be coupled to the heat storage device of FIGS. 1A-1B.
[0006] FIG. 2 schematically shows an example heat recovery system
including the heat storage device of FIGS. 1A-1B.
[0007] FIG. 3 schematically shows an example method for operating
the heat recovery system of FIG. 2.
DETAILED DESCRIPTION
[0008] The following description relates to a heat storage device
of a heat transfer system including phase changing materials, which
are arranged in such a way that thermal energy from an exhaust
system can be recovered. The example arrangements described herein
allow thermal energy to be recovered and stored for later heating
of a passenger compartment, for example.
[0009] As indicated, the heat transfer system may utilize a heat
storage device to transfer heat even when the engine is not in
operation. For example, the heat storage device may be in fluidic
communication with an exhaust system component downstream from the
catalytic converter, such as via heat exchanger. In this way, heat
may transfer from the heat storage device even after the engine is
no longer in operation. For example, the heat storage device may be
insulated to store heat recovered from the exhaust system, which
may be available for immediate use at engine start.
[0010] Additionally, the heat transfer system may include various
heat transfer fluids to extract thermal energy from the exhaust
system under a variety of different operating conditions. In this
way, thermal energy may be recovered from the exhaust system to
provide heat to various other systems such as a cabin heating
system, lubrication systems, and/or other exhaust system
components, if desired.
[0011] Further, the example systems allow for a simpler and more
compact design as compared to traditional designs. For example, the
heat storage device may provide heat to a cabin heating system at
engine start, as introduced above. By coupling the heat storage
device to a component of the exhaust system downstream from the
catalytic converter, the cabin heating system may provide heat to
the passenger cabin at engine start without relying upon a coolant
system, and therefore, without waiting for the coolant system to
warm up at engine start. Further, the system may provide the stored
heat to the cabin heating system without delaying catalytic
converter light-off, as described above.
[0012] FIGS. 1A and 1B show a heat storage device 100 according to
an embodiment of the present disclosure. FIG. 1A shows a
perspective exterior view and FIG. 1B shows a perspective cross
sectional view of heat storage device 100 taken along plane B. FIG.
1 shows an example bypass heat exchanger that may be coupled to
heat storage device 100.
[0013] Referring first to FIG. 1A, heat storage device 100 may be a
cylindrical shape. In other words, heat storage device 100 may have
a circular cross section. Further, heat storage device 100 may be
tilted by an angle 101 from a horizontal. Such an angle may
facilitate efficient heat transfer through the device. As used
herein, the horizontal refers to the ground over which the vehicle
travels. For example, FIG. 1A shows a horizontal axis 102 and a
vertical axis 104. The vertical axis may be orthogonal to the
horizontal axis. Therefore, the vertical axis may be orthogonal to
the ground over which the vehicle travels. As shown, heat storage
device 100 may be tilted angle 101 from horizontal axis 102. In
some embodiments, heat storage device 100 may be tilted 5.degree.
from the horizontal; however, it will be appreciated that other
angles are possible without departing from the scope of this
disclosure. Further, in some embodiments, heat storage device 100
may not be tilted. For example, heat storage device 100 may be
level with the horizontal. In other words, angle 101 may be zero
degrees.
[0014] As shown, heat storage device 100 includes an inlet passage
106 and an outlet passage 108. The inlet and outlet passages may
carry a heat transfer fluid. Further, the heat storage device may
house a phase changing material (PCM).
[0015] Inlet passage 106 may be coupled to heat storage device 100
at a central position. For example, inlet passage 106 may be
coupled to a first end 110 of heat storage device 100 at the
central position. In other words, inlet passage 106 may have a
central axis 112 that is shared with a central axis of end 110, and
further, shared with a central axis of heat storage device 100.
Inlet passage 106 may be configured to supply heat storage device
100 with heat recovered from the exhaust system, for example. In
some embodiments, the heat transfer fluid of inlet passage 106 may
be coupled to a pump (not shown) to drive a movement of the heat
transfer fluid. Further, a bypassable heat exchanger may be
positioned upstream from inlet passage 106. Such a heat exchanger
is discussed further with reference to FIG. 1C. Further, inlet
passage 106 may include a portion that extends into an interior 114
of heat storage device 100.
[0016] Outlet passage 108 may be coupled to heat storage device 100
at a top position. For example, outlet passage 108 may be coupled
to a second end 116 of heat storage device 100 at the top position.
In other words, outlet passage 108 may have a central axis 118 that
is a distance 120 from shared central axis 112 in a vertical
direction (e.g., along vertical axis 104). In this way, outlet
passage 108 is positioned towards a periphery of end 116, rather
than centrally located, to advantageously reduce bubble
accumulation in the heat transfer fluid. However, in some
embodiments, outlet passage 108 may be centrally located at end
116, if desired. Outlet passage 108 may be configured to transfer
heat from heat storage device 100 to another system of the vehicle.
For example, outlet passage 108 may transfer stored heat to the
cabin heating system, the coolant system, the lubrication system,
and/or another system of the vehicle. Further, outlet passage 108
may include a portion that extends into the interior 114 of heat
storage device 100.
[0017] As shown, heat storage device 100 includes a vacuum passage
122. For example, vacuum passage 122 may be coupled to heat storage
device 100 at end 116. Vacuum passage 122 may be coupled to both
heat storage device 100 and a vacuum pump (not shown). For example,
in some embodiments, heat storage device 100 may include a vacuum
jacket, and vacuum passage 122 may be a conduit for evacuating an
airspace within the vacuum jacket. In this way, a pressure within
at least a portion of interior 114 may be reduced. In some
embodiments, the pressure within interior 114 may be reduced to 1
microbar or less.
[0018] FIG. 1B shows a perspective interior view of heat storage
device 100. As shown, heat storage device 100 may be double walled.
In other words, heat storage device 100 may include an outer vessel
124 and an inner vessel 126. For example, heat storage device may
include outer walls 128 and inner walls 130. Further, heat storage
device may include vacuum jacket 132 positioned between outer walls
128 and inner walls 130. As described above, vacuum passage 122,
along with a vacuum pump, may suction air out of vacuum jacket 132
such that a pressure within vacuum jacket 132 is reduced.
[0019] Vacuum jacket 132 may hold a reduced pressure around an
exterior of inner vessel 126 when a vacuum is applied. By applying
a vacuum, water vapor and other gaseous compounds can be evacuated
from the surfaces of the insulating layers as hot fluid is pumped
through the heat transfer fluid passages. Further, vacuum jacket
132 may include one or more anti-radiation foils 134 that reduce
heat loss to the surrounding environment via radiation.
[0020] It will be appreciated that the perspective view of FIG. 1B
shows a longitudinal cross section of the heat storage device 100,
thus it will be appreciated that outer walls 128, inner walls 130,
and vacuum jacket 132 extend circumferentially around a perimeter
of heat storage device 100 and longitudinally, for example, along
axis 112.
[0021] Further, at least a portion of inlet passage 106 and outlet
passage 108 may be double walled and include a vacuum space. For
example, portions 136 exterior to heat storage device 100 may be
double walled similar to the inner and outer vessels. Further,
vacuum spaces 138 of the inlet and outlet passages may coalesce
with vacuum jacket 132 of the heat storage device.
[0022] Heat storage device 100 may include one or more axial
supports 140. Axial supports 140 may couple inner vessel 126 to
outer vessel 124 such that the inner vessels is suspended and
supported within the outer vessel. As shown, axial supports 140 may
be coupled to outer walls 128 and inner walls 130, and thus, may be
positioned within vacuum jacket 132. The axial supports may be
composed of a material with low heat conducting properties. For
example, axial supports 140 may be composed of titanium or a
composite including titanium or another material with low heat
conducting properties. Further, in some embodiments the axial
supports may be perforated to further reduce heat loss to the
surrounding environment.
[0023] Further, the inner vessel may be additionally and/or
alternatively supported by radial supports 142. Such radial
supports may be located circumferentially at various positions. As
shown, radial supports 142 may be coupled to outer walls 128 and
inner walls 130, and thus, may be positioned within vacuum jacket
132. Similar to the axial supports, the radial supports 142 may be
composed of titanium or a composite including titanium or another
material with low heat conducting properties. Further, in some
embodiments the radial supports may be perforated to further reduce
heat loss to the surrounding environment.
[0024] As shown, heat storage device 100 includes two axial
supports at end 110, one axial support at end 116, and four radial
supports 142. It will be appreciated that the number of axial and
radial supports shown is non-limiting and another number of
supports and/or another configuration of supports is possible
without departing from the scope of this disclosure. The supports
are provided to illustrate a general concept of a configuration
enabling heat storage device 100 to withstand gravitational
acceleration forces that may occur when the heat storage device 100
is rigidly coupled to the vehicle body.
[0025] Heat storage device 100 may further include a phase changing
material (PCM) stack 144 supported between retention plates 146 via
one or more springs 148. PCM stack 144 may include a plurality of
PCM elements 150 arranged radially about a central feed passage
152. In some embodiments, the configuration of the PCM stack is
such that the PCM stack retains 80% of stored heat for at least 16
hours, which may be used as a heat source at engine start to heat
the passenger cabin, as described above. Further, heat stored in
PCM stack 144 may be discharged to heat the passenger cabin or
another engine system without starting the engine. For example, PCM
stack discharge may be initiated remotely and does not necessarily
have to coincide with engine-start. However, PCM stack discharge
may be initiated remotely along with engine-start, for example,
using a remote starter to start engine 12.
[0026] The plurality of PCM elements 150 include a phase changing
material capable of storing a large quantity of heat in a form of a
latent heat of fusion. Since the plurality of PCM elements 150 are
surrounded by the double wall configuration, heat storing
capabilities are enhanced. In other words, the double wall
configuration acts like a thermos to retain heat stored within the
plurality of PCM elements 150. In some embodiments, each PCM
element may include the same phase changing material, and thus, the
PCM stack may have one phase transfer temperature. In other
embodiments, the PCM stack may include PCM elements with different
phase changing materials, wherein each different phase changing
material has a different phase transfer temperature. In such an
example, a time to charge the PCM stack may be reduced. In other
words, the time for the PCM stack to reach a maximum heat storing
potential may be reduced.
[0027] As shown, heat transfer fluid may be delivered to PCM stack
144 via centrally located inlet passage 106, and further, via
center feed passage 152. Thus, it will be appreciated that inlet
passage 106 is in fluidic communication with center feed passage
152. Thus, heat transfer fluid flows radially from center feed
passage 152 to the plurality of PCM elements 150. Heat transfer
fluid exits the heat storage device via outlet passage 108 arranged
in the top position, as described above.
[0028] As the heat transfer fluid flows through the PCM stack, a
pressure drop occurs. To reduce the pressure drop, the inlet
passage 106 and the outlet passage 108 are straight. In other
words, the inlet passage 106 and the outlet passage 108 do not
include bends. Further, the inlet passage 106 and the outlet
passage 108 do not include corrugations. Due to the absence of
corrugations, a rate of heat loss may potentially increase.
However, since the inlet and outlet passages include a vacuum space
around a circumference of these passages, such a potential for heat
loss is reduced.
[0029] As shown, retention plates 146 may be positioned at either
end of PCM stack 144. For example, one retention plate 146 may be
positioned proximate to end 110, and another retention plate 146
may be positioned proximate to end 116. Retention plates 146 may be
a circular shape and may have a diameter that is approximately
equal to a diameter of PCM stack 144. As another example, retention
plates 146 may have a larger diameter or a smaller diameter than
PCM stack 144. The retention plates may be coupled to the inner
vessel via one or more plate extensions with windows 154 to allow
HTF to reach exit 108. Six axial rods (not shown) allow retention
of the PCM stack in the radial and circumferential directions. The
rods are welded to the retention plates. As such, the PCM stack is
retained inside inner vessel 126 to reduce the potential for stack
element sliding and/or rotation during vehicle operation.
[0030] Further, one or more springs 148 may further maintain the
position of the PCM stack. As shown, one or more springs 148 may be
positioned proximate to end 116 between retention plate 146 and
inner walls 130. Springs 148 may be configured to ensure proper
contact between the PCM elements during thermal expansion and
thermal compression that results from the heat transfer fluid
heating and cooling. In some embodiments, springs 148 may have a
combined force of 100 Newtons or higher to maintain proper contact
between the PCM elements. As shown in FIG. 1B, heat storage device
100 may include five springs; however the heat storage device may
include more than five springs or less than five springs, if
desired.
[0031] FIG. 1C schematically shows a heat exchanger 156 thermally
coupled to exhaust passage 14. In some embodiments, heat exchanger
156 may be thermally coupled to exhaust passage 14 at a position
between engine 12 and one or more exhaust emission control devices
16. For example, heat exchanger 156 may be thermally coupled to
exhaust passage 14 upstream from an oxidation catalyst such as a
diesel oxidation catalyst (DOC). Heat exchanger 156 may be
fluidically coupled to heat storage device 100 via inlet passage
106. For example, heat exchanger 156 may be thermally coupled to
inlet passage 106 at a position upstream from heat storage device
100. In some embodiments, heat exchanger 156 may be an evaporative
region to extract heat from heat passage 14 and provide said heat
to heat storage device 100 by way of inlet passage 106. For
example, heat exchanger 156 may include heat transfer tubing that
carries heat transfer fluid supplied by an engine-driven pump to
flow inside the tubing. As another example, the heat transfer
tubing may carry heat transfer fluid supplied by an
electrically-driven pump to flow inside the tubing. Such a
configuration of heat transfer tubing may be fluidically coupled to
inlet passage 106. As one example, the heat transfer fluid of the
tubing may be the same heat transfer fluid of inlet passage 106. As
another example, the heat transfer fluid of the tubing may be a
different fluid than the heat transfer fluid of inlet passage
106.
[0032] In some embodiments, heat exchanger 156 is a
liquid-to-liquid heat exchanger. In other embodiments, the heat
exchanger 156 could be a gas-to-liquid or gas-to-thermosyphon heat
exchanger.
[0033] Further, exhaust passage 14 may include a bypass valve 158
that directs exhaust gas flow through heat exchanger 156. Bypass
valve 158 is shown in a bypass position (e.g., a closed position)
in FIG. 1C. Bypass valve 158 may be actuated via a controller, or
bypass valve 158 may be a passive valve, if desired. Bypass valve
158 may be in an open position (e.g., exhaust gases are not
diverted to heat exchanger 156) when exhaust back pressure reaches
a threshold value. For example, bypass valve 158 may be closed at
high exhaust flows and/or high exhaust temperatures. As such,
bypass valve 158 may reduce loss of engine output, and therefore,
may reduce fuel consumption.
[0034] It will be appreciated that the disclosed system may include
more than one heat exchanger. For example, a heat exchanger may be
positioned upstream from inlet passage 106, and one or more heat
exchangers may be positioned downstream from outlet passage 108.
For example, a heat exchanger may be positioned at an interface
between the heat recovery system and another system of the vehicle.
Such a configuration is described in further detail with respect to
FIG. 2.
[0035] It will be appreciated that FIGS. 1A-1C are shown in
simplified form and that numerous variations are possible without
departing from the scope of this disclosure. Further, heat storage
device 100 may include additional and/or alternative components
than those illustrated in FIGS. 1A and 1B. Further still, it is to
be understood that heat storage device 100 is provided to
illustrate a general concept, and thus, numerous geometric
configurations are possible without departing from the scope of
this disclosure.
[0036] FIG. 2 schematically shows a heat recovery system 200
including heat storage device 100 and a plurality of heat
exchangers. FIG. 2 includes similar features as FIG. 1, and like
features are indicated with common reference numbers. Such features
will not be discussed repetitively for the sake of brevity.
[0037] As shown, heat recovery system 200 includes heat exchanger
156 to recover heat from exhaust system 10, as described above.
Heat recovery system 200 may further include one or more additional
heat exchangers 202. Heat exchangers 202 may transfer heat between
heat recovery system 200 and another engine system 203. For
example, heat exchangers 202 may transfer heat to coolant system
204, cabin heating system 228, and/or transmission system 206. In
other words, heat exchangers 202 may be thermally coupled (e.g., in
thermal contact) with a fluid of the coolant system 204, the cabin
heating system 228 and/or the transmission system 206 to transfer
heat to each respective system.
[0038] It will be appreciated that each of the engine systems 203
are separate systems from heat recovery system 200 and exhaust
system 10. As such, engine systems 203 include components that are
separate from the components of heat recovery system 200 and
exhaust system 10. Thus, engine systems 203 do not include heat
exchanger 156, heat exchangers 202, heat storage device 100, or
another component of heat recovery system 200 and exhaust system
10. For example, cabin heating system 228 may include a heater core
and a fan, wherein the heater core and the fan are separate from
the heat recovery system and the exhaust system. Thus it is to be
understood that only a fluid conduit (e.g., a coolant passage) of
each engine system 203 is in thermal contact with the heat recovery
system 200 at a position coinciding with the heat exchanger 202,
for example. In this way, heat transfer occurs at the heat
exchanger.
[0039] It will be appreciated that one or more of the heat
exchangers may be gas-to-liquid and/or gas-to-thermosyphon heat
exchangers. As shown, heat exchangers 202 may be thermally coupled
to an engine system in parallel. In some embodiments, heat
exchangers 202 may be thermally coupled to each of the engine
systems in series. For example, heat transfer fluid may flow
through a series of heat exchangers 202 fluidically coupled to a
common heat transfer fluid passage.
[0040] As shown, heat transfer fluid (HTF) may flow through a heat
exchanger and may thermally transfer heat to a fluid of one or more
of the aforementioned systems. Arrows 208 generally indicate a
direction of HTF flow, and arrows 210 generally indicate a
direction of fluid flow for each engine system. Pump 212 may drive
HTF fluid flow through heat recovery system 200. As shown, pump 212
is positioned upstream from heat exchanger 156; however, another
position is possible without departing from the scope of this
disclosure. Further, it will be appreciated that coolant system
204, cabin heating system 228 and/or the transmission system 206
may have another driving mechanism to drive fluid flow through each
respective system. For example, each engine system 203 may have a
pump, similar to pump 212, fluidically coupled to the fluid
flow.
[0041] Heat recovery system 200 may further include one or more
control valves 214, one or more variable position valves 216, one
or more manifolds such as manifold 218 and manifold 220, and
expansion device 222.
[0042] Control valves 214 may be actuated by a controller (not
shown) to regulate HTF flow through heat recovery system 200. As
shown, a control valve may be positioned upstream from one of the
heat exchangers 202, upstream from heat storage device 100, and/or
at another position within heat recovery system 200 to regulate HTF
flow. Depending on an operational state of the vehicle, one or more
of the control valves may be actuated to regulate a temperature of
the HTF. For example, when one or more control valves are closed, a
volume of circulating HTF can be reduced such that the HTF can
increase in temperature more rapidly.
[0043] Further, the HTF temperature may be regulated via actuation
of variable control valve 216. Such a control valve may be actuated
to open at varying degrees to change a fluid flux of the HTF
passing through variable control valve 216. As shown, variable
control valve 216 is positioned upstream from manifold 220, and is
included within bypass loop 224. Bypass loop 224 may bypass heat
storage device 100. Therefore, bypass loop 224 may allow HTF to
circulate without passing through heat storage device 100. For
example, to conserve heat stored in heat storage device 100,
variable control valve 216 may be adjusted to allow HTF fluid flow
to flow through bypass loop 224. In other words, bypass loop 224
may be a blending loop that blends cooler HTF fluid with warmer HTF
fluid that circulates through heat exchanger 156, heat storage
device 100, and/or one or more heat exchangers 202. By blending HTF
circulating through bypass loop 224 with other circulating HTF
flow, an overall temperature of the circulating HTF may be
reduced.
[0044] Further still, the HTF temperature may be regulated by
routing all circulating HTF flow through bypass loop 226. For
example, bypass loop 226 may be an exhaust temperature boosting
loop and bypass loop 226 may be a thermal recharging loop,
depending on the operational state of engine 12 and/or the thermal
capacity of heat storage device 100. For example, bypass loop 226
may function as the exhaust temperature boosting loop when heat
storage device 100 holds a thermal charge and the exhaust
temperature is below a threshold value. Further, heat exchanger 156
may be positioned upstream from one or more exhaust emissions
control devices and heat storage device 100 may discharge heated
HTF to be delivered to heat exchanger 156. In this way, heated HTF
may only be circulated through bypass loop 226 to increase a
temperature of the exhaust flow, such that a time to reach catalyst
light-off is reduced.
[0045] Further, as the thermal recharging loop, bypass loop 226 may
extract heat from the exhaust flow to recharge heat storage device
100. Thus, HTF may only flow through thermal charging loop 225 to
increase the temperature of HTF via heat exchanger 156. In this
way, HTF may be heated by the exhaust flow to recharge the thermal
capacity of heat storage device 100. It may be advantageous to
recharge heat storage device 100 in this way when a temperature of
the heat storage device is below a threshold value. For example,
after heat storage device has discharge its thermal capacity,
and/or after the various engine systems are sufficiently warm.
[0046] In other words, one or more control valves 214 positioned
upstream from heat exchangers 202 may be closed to reduce a volume
of circulating HTF, and/or variable position control valve 216 may
also be closed, such that circulating HTF only passes through
bypass loop 226, heat exchanger 156, and heat storage device 100. A
method for regulating HTF flow through heat recovery system 200 by
actuating one or more control valves is described with respect to
FIG. 3.
[0047] As shown, manifolds 218 and 220 may be positioned in heat
recovery system 200 where more than one pipe carrying HTF fluid
merges. For example, manifold 218 may be configured to receive HTF
fluid from one pipe and may include two HTF outlets. As another
example, manifold 220 may be configured to receive HTF fluid from
more than one pipe and may include more than one outlet. As shown,
manifold 220 receives HTF flow from heat storage device 100 and
from bypass loop 224. Further, manifold 220 may have an outlet
directed towards each heat exchanger 202 and/or to thermal charging
loop 225. It will be appreciated that manifolds 218 and 220 are
provided as non-limiting examples, and thus, other configurations
are possible without departing from the scope of this
disclosure.
[0048] Expansion device 222 may be positioned downstream from the
plurality of heat exchangers 202. As shown, expansion device 222 is
configured to receive HTF from each of the heat exchangers 202, as
well as thermal recharging loop 225. For example, expansion device
222 may be provided for degassing. In other words, expansion device
222 may be positioned downstream from heat exchangers 202 and
thermal recharging loop 225 to regulate a pressure of the incoming
HTF flow.
[0049] It will be appreciated that heat recovery system 200 is
provided by way of example, and thus, is not meant to be limiting.
Therefore, it is to be understood that heat recovery system 200 may
include additional and/or alternative features than those
illustrated in FIG. 2 without departing from the scope of this
disclosure. For example, the heat recovery system may include a
three-way valve to regulate HTF flow to more than one engine
system.
[0050] FIG. 3 schematically shows an example method 300 that may be
used to operate heat recovery system 200.
[0051] At 302, method 300 includes determining if an engine has
started. If the answer to 302 is NO, method 300 ends. If the answer
to 302 is YES, method 300 continues to 304.
[0052] At 304, method 300 includes determining if an HTF
temperature is below a threshold value. For example, the exhaust
temperature may be an exhaust gas temperature upstream and/or
downstream from an emissions control device. If the answer to 304
is YES, method 300 continues to 306. If the answer to 304 is NO,
method 300 continues to 308.
[0053] At 306, method 300 includes reducing a volume of circulating
heat transfer fluid (HTF) and discharging a heat storage device
(e.g., heat storage device 100) to heat an exhaust system
component, such as an exhaust system component. For example,
reducing the volume may include closing one or more control valves
to inhibit the circulating heat transfer fluid from being
distributed to one or more engine systems. Further, discharging the
heat storage device may include discharging stored thermal energy
of the heat storage device, wherein the stored thermal energy is
stored from a previous engine operation. Further still, the stored
thermal energy may be transferred to the circulating heat transfer
fluid and distributed to the exhaust system component. In some
embodiments, the exhaust system component may be upstream from an
emissions control device.
[0054] At 308, method 300 includes distributing circulating HTF to
one or more engine systems. For example, one or more control valves
may be actuated to distribute circulating HTF to one or more of a
cabin heating system, an engine coolant system, a transmission
system, etc.
[0055] At 310, method 300 includes determining if the one or more
engine systems are sufficiently warm. If the answer to 310 is NO,
method 300 returns to 306. If the answer to 310 is YES, method 300
continues to 312.
[0056] At 312, method 300 includes recharging the heat storage
device. For example, the volume of circulating HTF may be reduced
and/or a bypass loop may be opened such that HTF is circulated
through a heat exchanger thermally coupled to the exhaust system
and through the heat storage device. In this way, a thermal
capacity of the heat storage device may be increased.
[0057] At 314, method 300 includes determining if a HTF temperature
is above a threshold value. For example, the HTF may become too
warm when the vehicle is in operation for an extended period of
time. If the answer to 314 is NO, method 300 continues to 316. If
the answer to 314 is YES, method 300 continues to 318.
[0058] At 316, method 300 includes closing a blending loop. As
such, the volume of circulating HTF is not adjusted in response to
the temperature of the HTF.
[0059] At 318, method 300 includes adjusting a variable position
valve of the blending loop. As such, a dead volume of HTF is
released from the blending loop to reduce the temperature of the
circulating HTF. As described above, the temperature of the HTF may
be regulated based on a position of the variable position valve.
For example, the valve may be fully opened to rapidly cool the HTF.
As another example, the valve may be partially opened to moderately
cool the HTF.
[0060] It will be appreciated that method 300 is provided by way of
example, and thus, is not meant to be limiting. Therefore, it is to
be understood that method 300 may include additional and/or
alternative steps than those illustrated in FIG. 3 without
departing from the scope of this disclosure. Further, it will be
appreciated that method 300 is not limited to the order
illustrated; rather, one or more steps may be rearranged or omitted
without departing from the scope of this disclosure. For example,
one or more portions of method 300 may occur without starting the
engine. As described above, the heat storage device may be
activated to discharge without operating the engine.
[0061] Various conduits may be referred to as pipes, which can
encompass various forms of conduits, passages, connections, etc.,
and are not limited to any specific cross-sectional geometry,
material, length, etc.
[0062] It will be appreciated that the configurations and routines
disclosed herein are exemplary in nature, and that these specific
embodiments are not to be considered in a limiting sense, because
numerous variations are possible. For example, the above technology
can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine
types. The subject matter of the present disclosure includes all
novel and non-obvious combinations and sub-combinations of the
various systems and configurations, and other features, functions,
and/or properties disclosed herein.
[0063] The following claims particularly point out certain
combinations and sub-combinations regarded as novel and
non-obvious. These claims may refer to "an" element or "a first"
element or the equivalent thereof. Such claims should be understood
to include incorporation of one or more such elements, neither
requiring nor excluding two or more such elements. Other
combinations and sub-combinations of the disclosed features,
functions, elements, and/or properties may be claimed through
amendment of the present claims or through presentation of new
claims in this or a related application. Such claims, whether
broader, narrower, equal, or different in scope to the original
claims, also are regarded as included within the subject matter of
the present disclosure.
* * * * *