U.S. patent application number 12/323728 was filed with the patent office on 2010-05-27 for heat recovery system.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Paulo A. Riedel, Johnson Wu.
Application Number | 20100126437 12/323728 |
Document ID | / |
Family ID | 42168959 |
Filed Date | 2010-05-27 |
United States Patent
Application |
20100126437 |
Kind Code |
A1 |
Riedel; Paulo A. ; et
al. |
May 27, 2010 |
HEAT RECOVERY SYSTEM
Abstract
The present invention is directed towards methods and systems
for heating an engine, particularly during initial start-up of the
engine. In one exemplary embodiment, a heat storage and release
system for an engine is provided. The system may include a material
capable of super cooling within an operating temperature range of
the engine. The material is in thermal communication with the
engine and may include an energy input device associated with the
material. The energy input device may be configured to input energy
to the material causing the material to undergo an exothermic phase
change. During the phase change the material releases heat to the
engine.
Inventors: |
Riedel; Paulo A.; (Rochester
Hills, MI) ; Wu; Johnson; (Sterling Heights,
MI) |
Correspondence
Address: |
Cantor Colburn LLP-General Motors
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
42168959 |
Appl. No.: |
12/323728 |
Filed: |
November 26, 2008 |
Current U.S.
Class: |
123/41.14 |
Current CPC
Class: |
F02N 19/10 20130101;
F01P 2011/205 20130101; F01P 2037/02 20130101; Y02E 60/145
20130101; F28D 20/028 20130101; F01P 11/20 20130101; Y02E 60/14
20130101; F28D 20/02 20130101 |
Class at
Publication: |
123/41.14 |
International
Class: |
F01P 11/02 20060101
F01P011/02 |
Claims
1. A heat storage and release system for an engine, comprising a
material, capable of super cooling within an operating temperature
range of the engine, in thermal communication with the engine; an
energy input device associated with the material and operable to
input energy to the material to initiate an exothermic phase change
therein and delivery of heat to the engine.
2. The heat storage and release system of claim 1, wherein the
exothermic phase change is from a super cooled, liquid state the to
a solid state of the material.
3. The heat storage and release system of claim 2, wherein the
material is further configured to absorb heat generated by the
engine, to thereby undergo a phase change from the solid state to a
liquid state.
4. The heat storage and release system of claim 1, wherein the
exothermic phases change may be initiated before the operation of
the engine.
5. The heat storage and release system of claim 1, wherein the
material comprises sodium acetate or sodium ethanaote.
6. The heat storage and release system of claim 1, further
comprising a structure defined by an engine for holding the
material.
7. The heat storage and release system of claim 1, further
comprising a separate structure associated with an engine for
holding the material.
8. The heat storage and release system of claim 1, wherein the
material is in thermal communication with an engine coolant.
9. The heat storage and release system of claim 1, wherein the
energy input device comprises a mechanical input device configured
to input mechanical energy to the material suitable for initiating
the exothermic phase change.
10. A method of storing and releasing heat for an engine,
comprising: placing a material, capable of super cooling within an
operating temperature range of the engine, in thermal communication
with the engine; absorbing heat generated by the engine with the
material; and inducing the material to undergo an exothermic phase
change wherein during the phase change the material releases the
absorbed heat to the engine.
11. The method of claim 10, wherein the super cooled state of the
material is at or below about 95.degree. C.
12. The method of claim 10, wherein the heat released by the
material is about 54.degree. F.
14. The method of claim 10, wherein during absorption of heat by
the material the material undergoes a phase change from solid to
liquid, and wherein during release of heat by the material the
material undergoes a phase change from a super cooled liquid, to a
solid.
15. The method of claim 10, wherein the material comprises sodium
acetate or sodium ethanaote.
16. The method of claim 10, further comprising placing the material
within the engine.
17. The method of claim 10, further comprising placing the material
within a separate structure that is associated with the engine.
18. The method of claim 10, wherein the phase change occurs during
operation of the engine.
19. The method of claim 10, wherein the phase change occurs prior
to operation of the engine.
20. The method of claim 10, wherein release of heat is initiated
with an energy input device, and wherein the energy input device
comprises a mechanical input device configured to input mechanical
energy to the material suitable for initiate the phase change of
the material.
Description
FIELD OF THE INVENTION
[0001] The invention is directed to methods and systems for heating
an engine, particularly during initial start-up.
BACKGROUND
[0002] Engines often have elevated levels of exhaust emissions
during initial start-up as associated exhaust treatment devices
have reached steady state operating temperatures. As such, the
efficiency of removal or treatment of exhaust emissions is
dependent upon the temperature of the engine exhaust gas and,
inherently, the engine. In cooler operating conditions engines may
have increased difficulty starting or have reduced fuel economy due
to lower initial operating temperatures. Existing solutions that
assist engine cold starts may be costly, with respect to necessary
product and energy use, and can be cumbersome to use. Accordingly,
there is a need for an improved system and method for providing
heat to an engine before or during initial start-up of the
engine.
SUMMARY OF THE INVENTION
[0003] An embodiment of the invention is directed towards methods
and systems for heating an engine, particularly during initial
start-up of the engine. In one exemplary embodiment, a heat storage
and release system for an engine is provided. The system may
include a material capable of being super cooled within the
operating temperature range of the engine. The material is in
thermal communication with the engine. In other non-limiting
examples, the system also includes an energy input device
associated with the material. The energy input device delivers
energy to the super cooled material sufficient to initiate an
exothermic phase change. During the phase change the material
releases heat to the engine.
[0004] In another embodiment, a method of storing and releasing
energy, in the form of heat, to an engine is provided. The method
includes forming a structure having a cavity containing a material
capable of super cooling within an operating temperature range of
the engine and locating the structure in thermal communication with
the engine. The method also includes absorbing heat generated by
the engine with the material and inducing a phase change of the
material from a super cooled state to thereby release the stored
heat to the engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Other features, advantages and details appear, by way of
example only, in the following detailed description of embodiments,
the detailed description referring to the drawings in which:
[0006] FIG. 1 illustrates a schematic view of an engine with a heat
recovery system of the present invention in a first mode of
operation;
[0007] FIG. 2 illustrates a schematic view of an engine with the
heat recovery system shown in FIG. 1 in a second mode of operation;
and
[0008] FIG. 3 illustrates a schematic view of an engine with the
heat recovery system shown in FIG. 1 in a third mode of
operation.
DESCRIPTION OF THE EMBODIMENTS
[0009] The present invention provides methods and systems for
improving emissions, performance and efficiency of an engine during
initial operation thereof. These and other benefits are achieved
through the absorption, storage and release of potential energy,
particularly heat, generated by an engine. In particular, a heat
storage material capable of the absorption, storage and release of
heat is provided. The material is in thermal communication with an
engine and/or a coolant flowing therethrough. The heat storage
material is configured to absorb heat generated by the engine
during operation of the engine. Thereafter, as the engine cools the
heat storage material retains at least a portion of the stored
energy for later release, particularly during a subsequent start-up
of the engine. When additional heat is desired for the engine, the
heat storage material is caused to release the stored heat to the
engine.
[0010] In one particular configuration of the heat storage
material, during operation of the engine, the heat storage material
absorbs heat generated by the engine causing the material to exist
in a first physical state (e.g., liquid). The heat storage material
remains super cooled in its first physical state after operation of
the engine has been discontinued and the engine has cooled to
ambient temperatures. Prior to, or during, a subsequent start-up of
the engine, the heat storage material is caused to change to a
second physical state (e.g., solid) wherein heat is released,
generally in a steady-state manner, during and after transition of
the heat storage material from the super cooled liquid state to the
solid state. The release of heat lowers the heating time of the
engine thereby providing improved emission reduction, performance
and efficiency.
[0011] In one configuration, the heat storage material exists in a
liquid physical state at or above its melting temperature and
exists in a liquid or a solid physical state at or below its
freezing temperature. When the heat storage material exists as a
liquid below its freezing point, the heat storage material is
commonly referred to as being super cooled or, in a super cooled
state. In this super cooled state, the heat storage material
requires additional energy to transform from a liquid state to a
solid state (i.e., cause crystallization of the heat storage
material).
[0012] The operating temperature of the engine ranges from the cold
start temperature of the engine to a steady state operating
temperature of the engine. While the cold start temperature of the
engine will vary seasonally and regionally, the steady state
operating temperature will be somewhat constant. It should be
appreciated that the steady state operating temperature may vary by
engine make, model, and operating conditions such as temperature
and load. In general though, the operating temperature of an
automotive internal combustion engine is generally between about
-40.degree. to 129.degree. C. As such, the heat storage material of
the present invention is also capable of super cooling within that
range.
[0013] Suitable heat storage materials contemplated by the present
invention include material capable of storing heat across the
operating temperature range of an engine. In one exemplary
embodiment, the heat storage material is capable of existing in a
super cooled state within the operating temperature range of the
engine. Such suitable heat storage materials include materials
having a melting temperature below the steady state operating
temperature of the engine and a freezing temperature above a cold
start temperature of the engine. Further, the suitable materials
will release heat (i.e. change phases from a super cooled liquid to
a solid) at a temperature above the cold start temperature of the
engine. As such, the suitable material melts during an operational
temperature of the engine and is super cooled below steady state
operational temperatures of the engine. When the super cooled
material undergoes a phase change, the engine is heated due to the
release of heat by the heat storage material.
[0014] Specific examples of suitable heat storage materials include
sodium acetate, sodium ethanaote, disodium hydrogen phosphate
dodecahydrate and the like. In one particular configuration, the
heat storage material comprises a sodium salt of an acetic acid,
such as sodium acetate. Sodium acetate comprises a material capable
of relatively easily existing in more than one physical state
within a given temperature range. For example, sodium acetate has a
melting temperature above about 95.degree. C. and a solidification,
or freezing temperature of about 54.degree. C. However, due to the
inherent characteristics of sodium acetate, it can exist in a
liquid phase at temperatures notably below 54.degree. C., including
ambient temperatures commonly encountered by engines, particularly
vehicle engines. In order to initiate solidification of super
cooled liquid sodium acetate the sodium acetate must be
sufficiently activated or disturbed, such as through the energy
input device. Upon disturbance, the sodium acetate changes phase
from a liquid to a solid. During this exothermic phase change, the
sodium acetate heats to a temperature of about 54.degree. C.
[0015] Referring to FIGS. 1-3, schematic views of an exemplary
embodiment of the present invention are shown. In this embodiment,
a heat recovery system 10 is provided for absorption of heat from
an engine 18 and for subsequent release of the absorbed heat to the
engine. The heat recovery system 10 includes a structure 12
defining a cavity 14 that receives a heat storage material. The
structure 12, containing heat storage material 16, is in thermal
communication with an engine 18 and, more particularly, in one
embodiment an engine block 20 or engine cylinder head 25. The
structure 12 containing the heat storage material 16 may also be in
thermal communication with an engine coolant 22 flowing through a
coolant flow path 24 defined by the engine block 20 and engine
cylinder head 25.
[0016] In one exemplary operation of the heat recovery system 10,
referring to FIG. 1, energy input device 26 induces an exothermic
phase change in the heat storage material 16. During the phase
change, referring to FIG. 2, the heat storage material 16
transforms from a first physical state (super cooled liquid) to a
second physical state (solid). This phase change results in the
release of heat, by heat storage material 16, causing the engine 18
and engine coolant 22 to be heated. The addition of heat is
additive to the inherent heating capabilities of the engine 18
during operation. The heat generated by the engine 18 and the heat
storage material 16 is circulated through the engine block 20, via
engine coolant 22. Once the temperature of the engine 18 and engine
coolant 22 reach suitable levels, see FIG. 3, the coolant is
further circulated through an engine cooling system 28 which may
include a radiator 30 or otherwise. During this time, or at any
time when the temperature of the engine is greater than the
temperature of the heat storage material 16, the heat storage
material 16 absorbs heat generated by the engine 18. During heat
absorption, the solid heat storage material 16 undergoes a physical
phase change back to the liquid state. Upon termination of engine
operation and cooling of the engine 18 to ambient temperatures, the
heat storage material 16 enters a super cooled, liquid state. In
this state the material 16 is again ready to release stored energy,
in the form of heat, to the engine 18 upon subsequent operation of
the energy input device 26.
[0017] It should be appreciated that the engine 18 may include more
than one heat recovery system 10, each of which may function to
provide simultaneous heating, sequential heating or other heating
solutions. For example, in one configuration it is contemplated
that one or more heat recovery systems 10 may be associated with
each cylinder head 25 of the engine 18. These heat recovery systems
10 may extend along all or a portion of the length or width of an
engine. It should be appreciated that different configurations are
available for obtaining a desired heating result.
[0018] As described, the exothermic phase change of the heat
storage material 16 is initiated through an energy input device 26.
The device may be mechanical in function and may be located inside
or outside of the structure 12 where it operates to deliver
mechanical energy sufficient to initiate an the liquid to solid
phase change in the heat storage material 16. Such mechanical
energy may be in the form of waves initiated through percussion,
vibration or otherwise. It should be appreciated that various
configurations may be used for the generation of waves or other
mechanical energy to the heat storage material 16. For example, in
one configuration a moveable member maybe provided that is
configured to strike the structure 12 containing the heat storage
material 16 thereby transmitting energy waves through the material
and initiating a phase change therein. Such movable members may
comprise a pin, hammer, or other suitable percussion member and may
move through the use of a solenoid (electrically driven,
pneumatically driven or otherwise), or the like. In another
configuration, the moveable member is configured to move the
structure 12 with sufficient force to cause disturbance and
initiate the phase change of the heat storage material 16. Other
configurations are contemplated.
[0019] The energy input device 26 may be activated at different
times and through different activation devices 32. The energy input
device 26 may be activated during an operational cycle of the
engine, during a non-operational cycle of the engine, or both. In
one exemplary embodiment, the energy input device 26 is activated
prior to ignition of the engine 18. For example, the energy input
device may be associated with a suitable controller for activation
of the energy input device during approach of an operator to the
vehicle, during unlocking of a vehicle door, upon placement in, or
rotation of, a key in an ignition system of the engine 18, or
otherwise. In another configuration, the energy input device is
activated during start-up of the engine. This may be through an
activation device 32 or through the natural vibration of the engine
18 during starting. In still another exemplary embodiment, the
energy input device 26 may be activated after initial ignition of
the engine. In configurations where more than one energy input
device 26 is used, it is contemplated that the energy input devices
may be activated simultaneously or at different times, such as
sequentially or otherwise.
[0020] The activation device 32 may comprise any suitable device
capable of transmitting signals to the energy input device 26. In
one configuration, the activation device comprises a remote device,
such as a remote keyless entry fob of a vehicle. In another
configuration, the activation device 32 comprises a control device
associated with a vehicle, such as an engine or vehicle controller.
In this configuration, the controller may be in communication with
the remote device, a sensor associated with the ignition, an entry
handle of the vehicle or otherwise. It should be appreciated that
other configurations are contemplated.
[0021] The heat storage material 16 is located within structure 12
that is in thermal communication with the engine 18 and optionally
the engine coolant 22 in coolant flow path 24. The structure 12 may
be located adjacent to the coolant flow path 24 of the engine 18.
In one exemplary embodiment, the structure 12 comprises a portion
of the engine 18, such as engine block 20 or engine cylinder head
25, and the cavity 14 is defined thereby. Hence, the structure 12
is integrally formed with the engine 18. In this configuration, the
heat storage material 16 is placed within the cavity 14 and the
cavity is subsequently sealed. In another configuration, the
structure 12 is formed separately from the engine block 18 or
engine cylinder head 25 and is attached to, or otherwise placed in
thermal communication therewith. In this configuration, the heat
storage material 16 is placed in the cavity 14 and the structure 12
is subsequently brought into association with the engine 18, such
as placement within an opening thereof, or mounting to (e.g.,
mechanically fastened, welded or otherwise) the engine block 20,
engine cylinder head 25 or otherwise. Other configurations are
possible.
[0022] The quantity of heat storage material 16 located within the
cavity 14 is dependent upon the quantity of heat desired for the
engine 18. It should be appreciated that the more heat storage
material 16 placed within the cavity 14 the more potential heat is
available for delivery to the engine 18. Accordingly, the quantity
of heat storage material 16 may be based upon, or proportional to,
the engines size and/or heating requirements.
[0023] Cavity 14 may comprise any suitable shape and/or size for
holding a sufficient quantity of heat storage material 16. In one
configuration, the cavity 14 is symmetrically shaped, such as a
cylinder to facilitate machining during production. In another
configuration, the cavity 14 may be asymmetrically shaped. This
latter configuration may be particularly advantageous where the
cavity 14 is cast into a structure comprising an engine block 20 or
engine cylinder head 25 and the cavity extends through all or a
portion of the engine block 20, engine cylinder head 25, or
otherwise. As such, the heat storage material may be located at
various locations within the engine 18 to provide desired heat
transfer to engine components and/or coolant. It should be
appreciated that the cavity may be formed during casting of the
engine block or engine head or may be subsequently machined
therein.
[0024] In one detailed sequence of operation, the heat recovery
system 10 is activated by activation device 32, which operates
energy input device 26, prior to or during an initial start-up of
the engine 18. Upon activation the heat storage material 16
undergoes an exothermic phase change from a super cooled, liquid
state to a solid state causing a release of heat to the engine 18.
During subsequent operation of the engine, the temperature of the
engine 18 and engine coolant 22 rise to levels that exceed the
melting point of the heat storage material 16 thereby causing a
return to a liquid phase. Once the engine is no longer in
operation, the engine 18, engine coolant 22 and heat recovery
system 10 cool to ambient conditions. However, due to inherent
properties described, the heat storage material 16, enclosed in the
structure 12, remains in a super cooled, liquid state upon cooling
below its melting point temperature. At this point, the heat
storage material 16 can be reactivated through the energy input
device 26 to again deliver heat to the engine 18. It should be
appreciated that the heat recovery system 10 may be regenerated, as
described, through the life of the vehicle without replenishment of
the heat storage material 10.
[0025] While exemplary embodiments have been described and shown,
it will be understood by those skilled in the art that various
changes may be made, and equivalents may be substituted, for
elements thereof without departing from the scope of the invention.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings without departing from the
essential scope thereof. Therefore, it is intended that the
invention not be limited to the particular embodiments disclosed as
the best mode contemplated for carrying out this invention, but
that the invention will include all embodiments falling within the
scope of the appended claims.
* * * * *