U.S. patent application number 12/133705 was filed with the patent office on 2009-12-10 for urea pump assembly for an exhaust gas treatment system.
Invention is credited to Oscar A. Lecea, Eugen Maier.
Application Number | 20090301064 12/133705 |
Document ID | / |
Family ID | 41399046 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090301064 |
Kind Code |
A1 |
Maier; Eugen ; et
al. |
December 10, 2009 |
UREA PUMP ASSEMBLY FOR AN EXHAUST GAS TREATMENT SYSTEM
Abstract
Exemplary embodiments of the present invention are directed
towards improved systems and methods for the delivery of urea to an
exhaust gas treatment system. In one exemplary embodiment, a urea
pump assembly for an exhaust treatment system is provided. The pump
assembly includes a housing comprising: a housing chamber, a first
fluid inlet and a first fluid outlet, the first fluid inlet being
in fluid communication with the first fluid outlet through a first
conduit. The housing also comprises a second fluid inlet and a
second fluid outlet, the second fluid inlet being in fluid
communication with the second fluid outlet through a second
flexible conduit. The second flexible conduit is located within a
portion of the housing chamber and in thermal communication with
the first conduit. The pump assembly also includes a pump located
within the housing chamber, the pump being engaged with the second
conduit and configured to move fluid between the second fluid inlet
and the second fluid outlet.
Inventors: |
Maier; Eugen; (Clarkston,
MI) ; Lecea; Oscar A.; (Grand Blanc, MI) |
Correspondence
Address: |
DELPHI TECHNOLOGIES, INC.
M/C 480-410-202, PO BOX 5052
TROY
MI
48007
US
|
Family ID: |
41399046 |
Appl. No.: |
12/133705 |
Filed: |
June 5, 2008 |
Current U.S.
Class: |
60/286 ; 415/17;
60/282; 60/303 |
Current CPC
Class: |
Y02T 10/12 20130101;
F01N 3/2066 20130101; F01N 2610/10 20130101; F01N 2610/1433
20130101; Y02T 10/24 20130101 |
Class at
Publication: |
60/286 ; 60/282;
60/303; 415/17 |
International
Class: |
F01N 3/00 20060101
F01N003/00 |
Claims
1. A urea pump assembly for an exhaust treatment system,
comprising: a housing comprising: a housing chamber, a first fluid
inlet and a first fluid outlet, the first fluid inlet being in
fluid communication with the first fluid outlet through a first
conduit, a second fluid inlet and a second fluid outlet, the second
fluid inlet being in fluid communication with the second fluid
outlet through a second flexible conduit, the second flexible
conduit being located within a portion of the housing chamber and
in thermal communication with the first conduit; and a pump located
within the housing chamber, the pump being engaged with the second
conduit and configured to move fluid between the second fluid inlet
and the second fluid outlet.
2. The urea pump assembly of claim 1, further comprising a first
valve for metering fluid through the first fluid inlet and a second
valve for metering fluid through the first fluid outlet.
3. The urea pump assembly of claim 2, wherein the first valve is
mounted to the housing through a first connector and the second
valve is mounted to the housing through a second connector.
4. The urea pump assembly of claim 1, further comprising an
electric heater located proximate to the second fluid inlet, the
second fluid outlet or both.
5. The urea pump assembly of claim 4, further comprising a
temperature sensor in thermal communication with the heater.
6. The urea pump assembly of claim 1, wherein the pump includes a
projecting member rotatable about an axis of the pump, the
projecting member configured to compress the flexible member and
thereby move a fluid in the flexible member from the second fluid
inlet to the second fluid outlet during rotation of the projecting
member.
7. The urea pump assembly of claim 6, wherein the flexible member
of the second conduit comprises a flexible tube, wherein the second
conduit is arcuate about the axis of the pump.
8. The urea pump assembly of claim 7, wherein the pump comprises a
positive displacement pump and the projecting member is rotatable
about the axis at a variable speed and is reversible, the variable
speed of the pump controlling a mass flow rate of the fluid flowing
through the second conduit.
9. The urea pump assembly of claim 1, further comprising a third
fluid inlet in fluid communication with the second conduit, the
third fluid inlet configured to supply air to the second
conduit.
10. An exhaust treatment system, comprising: an exhaust gas conduit
extending between an internal combustion engine and an exhaust gas
treatment device, the exhaust gas conduit being configured to guide
an exhaust gas stream from the internal combustion engine to the
exhaust gas treatment device for treatment of the exhaust gas
stream; a urea pump assembly for providing urea to the exhaust gas
stream, the urea pump assembly comprising: a housing having a first
conduit for receiving and guiding a first fluid from the internal
combustion engine through a first internal portion of the housing
and a second conduit in thermal communication with the first
conduit and the first fluid, the second conduit receiving and
guiding urea solution through a second internal portion of the
housing, a pump located in the second internal portion of the
housing, the pump causing movement of the urea solution along the
second conduit; and a fluid outlet in fluid communication with the
second conduit and the exhaust gas conduit or exhaust gas treatment
device, wherein the pump causes dispensing of the urea solution
into the exhaust gas stream through the fluid outlet.
11. The exhaust treatment system of claim 10, wherein the urea pump
assembly includes an electrical heater located along a portion of
the second conduit for heating the urea solution.
12. The exhaust treatment system of claim 10, wherein the pump
comprises a positive displacement pump that is variable in speed
and reversible, the pump being configured to control a mass flow
rate of the urea solution through the second conduit.
13. The exhaust treatment system of claim 12, wherein at least a
portion of the second conduit comprises a flexible member and
wherein the pump includes a projecting member rotatable about an
axis of the pump, the projecting member configured to compress the
flexible member to move urea solution along the second conduit and
towards the fluid outlet.
14. The exhaust treatment system of claim 10, further comprising a
control module in power or signal communication with a heater, a
temperature sensor, a pump motor, a valve or a combination
thereof.
15. A method of heating a urea solution for delivery to an exhaust
treatment system, comprising: fluidly coupling a urea pump assembly
to a first fluid system of an engine to provide a first fluid flow
through the urea pump assembly; fluidly coupling the urea pump
assembly to a urea solution supply to provide a urea solution to
the urea pump assembly; and activating a motor to cause movement of
the urea solution through the urea pump assembly and to cause
discharge of the urea solution into an exhaust gas stream, wherein
during movement of the urea solution through the urea pump assembly
the urea solution is heated by the first fluid.
16. The method of claim 15, wherein the urea pump assembly includes
an electric heater for heating the urea solution.
17. The method of claim 16, wherein the urea pump assembly includes
a temperature sensor for sensing the temperature of the urea
solution.
18. The method of claim 15, wherein the motor includes a positive
displacement pump that is variable in speed and reversible, the
variable speed of the pump controlling a mass flow rate of urea
solution through the urea pump assembly.
19. The method of claim 18, wherein the positive displacement pump
comprises a length of flexible conduit for guiding the urea
solution through the urea pump assembly, and wherein the pump
includes a projecting member rotatable about an axis of the pump,
the projecting member being configured to compress the flexible
member along its length to cause movement of the urea solution
through the urea pump assembly.
20. The method of claim 15, further comprising controlling the urea
pump assembly using a control module in power or signal
communication with a heater, a temperature sensor, a pump motor, a
valve or a combination thereof.
Description
FIELD OF THE INVENTION
[0001] Exemplary embodiments of the present invention are directed
towards improved systems and methods for the delivery of a urea
solution to an exhaust gas treatment system.
BACKGROUND
[0002] Exhaust emission control has been and will continue to be of
interest as effects of emissions from stationary and transient
emission generating devices are continually being understood. This,
along with government mandates, have caused manufacturers of
emission generating devices, particularly internal combustion
engines, to develop methods and devices for controlling the content
of emissions emanating from such devices. In one particular sector,
due to the advantage of diesel burning engines over gasoline
burning engines, advancements of emission control for diesel
engines are continuingly being sought. These advancements include
emission control devices configured for removing particulate matter
from an exhaust gas stream and/or converting certain exhaust gases,
such as NO.sub.X to other specific exhaust gas outputs such as
NO.sub.2 and CO.sub.2.
[0003] One particular advancement in the reduction of emissions
from diesel and gasoline burning engines is the application of an
ammonia solution to the exhaust gas stream prior to treatment by
one or more components of an exhaust gas treatment system. In one
particular configuration, a urea solution is added to the exhaust
gas stream. The addition of ammonia and/or urea solution improves
efficiency of the conversion of NO.sub.X. However, during certain
operation conditions, such as extreme cold temperatures, the
ammonia or urea solution may become frozen, thereby causing a loss
in the ability to inject the solution into the exhaust gas stream.
Further, increased effectiveness of the ammonia or urea may be
achieved at higher temperatures.
[0004] While certain injection systems have been provided for the
introduction of urea, few systems contemplate the addition of heat
for prevention of freezing of the ammonia or urea. This is in part
due to the relatively new application of urea to improve efficiency
of exhaust gas treatment components. When heating systems are
employed, such systems are located with an ammonia or urea supply
tank or along a supply line. However, these configurations require
the addition of components to the exhaust treatment system, thereby
adding further component and/or assembly cost. Further, these
heating systems often continually draw unnecessary energy (e.g.
electricity) away from the engine system thus reducing battery life
and/or power to the engine.
[0005] In view of the foregoing, there is a need for improved urea
delivery systems capable of heating ammonia, urea or other fluids
used for injection into an exhaust gas stream.
SUMMARY OF THE INVENTION
[0006] Exemplary embodiments of the present invention provide
improved systems and methods for the delivery of ammonia, urea or
other solution to an exhaust gas stream for use with an exhaust gas
treatment system.
[0007] In one exemplary embodiment, a urea pump assembly for an
exhaust treatment system is provided. The pump assembly includes a
housing comprising: a housing chamber, a first fluid inlet and a
first fluid outlet, the first fluid inlet being in fluid
communication with the first fluid outlet through a first conduit.
The housing also comprises a second fluid inlet and a second fluid
outlet, the second fluid inlet being in fluid communication with
the second fluid outlet through a second flexible conduit. The
second flexible conduit is located within a portion of the housing
chamber and is in thermal communication with the first conduit. The
pump assembly also includes a pump located within the housing
chamber, the pump being engaged with the second conduit and
configured to move fluid between the second fluid inlet and the
second fluid outlet.
[0008] In another exemplary embodiment, an exhaust treatment system
is provided. The exhaust treatment system includes an exhaust gas
conduit extending between an internal combustion engine and an
exhaust gas treatment device. The exhaust gas conduit is configured
to guide an exhaust gas stream from the internal combustion engine
to the exhaust gas treatment device for treatment of the exhaust
gas stream. The system also includes a urea pump assembly for
providing urea to the exhaust gas stream. The urea pump assembly
includes a housing having a first conduit configured for receiving
and guiding a first fluid from the internal combustion engine
through a first internal portion of the housing and a second
conduit in thermal communication with the first conduit and the
first fluid, the second conduit receives and guides urea solution
through a second internal portion of the housing. The pump assembly
also includes a pump located in the second internal portion for
causing movement of the urea solution along the second conduit. The
pump assembly further includes a fluid outlet in fluid
communication with the second conduit and the exhaust gas conduit
or exhaust gas treatment device, wherein the pump causes dispensing
of the urea solution into the exhaust gas stream through the fluid
outlet.
[0009] In yet another exemplary embodiment, a method of heating a
urea solution for delivery to an exhaust treatment system is
provided. The method includes: fluidly coupling a urea pump
assembly to a first fluid system of an engine to provide a first
fluid flow through the urea pump assembly; fluidly coupling the
urea pump assembly to a urea solution supply to provide a urea
solution to the urea pump assembly; and activating a motor to cause
movement of the urea solution through the urea pump assembly and to
cause discharge of the urea solution into an exhaust gas stream,
wherein during movement of the urea solution through the urea pump
assembly the urea solution is heated by the first fluid.
[0010] The above-described and other features and advantages will
be appreciated and understood by those skilled in the art from the
following detailed description, drawings, and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other objects, 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:
[0012] FIG. 1 illustrates a schematic view of the an exhaust gas
treatment system of an internal combustion engine including a urea
delivery device according to an exemplary embodiment of the present
invention;
[0013] FIG. 2 illustrates a perspective view of a urea pump
assembly according to an exemplary embodiment of the present
invention;
[0014] FIG. 3 illustrates another perspective view of the urea pump
assembly shown in FIG. 2;
[0015] FIG. 4 illustrates still another perspective view of the
urea pump assembly shown in FIG. 2; and
[0016] FIG. 5 illustrates a cross-sectional view of a urea pump
assembly according to an exemplary embodiment of the present
invention.
DESCRIPTION OF THE EMBODIMENTS
[0017] Exemplary embodiments of the present invention provide
improved devices, systems and methods for the delivery of urea
solution or other ammonia containing solution to an exhaust stream
of an internal combustion engine. Exemplary embodiments of the
present invention further provide devices, systems and methods for
the heating or thawing of urea solution or other ammonia containing
solution prior to delivery to an exhaust stream of an internal
combustion engine. It should be noted that an ammonia solution,
urea solution and other similar types of agent, derivative or
additive used for improving efficiency of exhaust treatment systems
are hereforth generally referred to as urea solution. However, this
should not be considered limiting as other solutions are
contemplated, as described herein.
[0018] Exemplary embodiments of the present invention provide
improvements to the delivery of urea solution to exhaust gas
treatment systems. This improvement is achieved, at least in part,
through a urea pump assembly fluidly connected to a vehicle fluid
system, such as an engine coolant system, for receiving and
utilizing heat from an engine to cause heating of the urea solution
prior to injection into an exhaust gas stream. The use of a fluid
heated in conjunction with operation of the engine, such as engine
coolant, reduces the overall need for energy, e.g., electricity,
for heating of the urea solution. Further, the improvements
optionally include multiple heating sources for additional heating
of the urea solution, an improved pump and other unique features
and advantages as shown and described herein.
[0019] Through exemplary embodiments of the present invention, the
effects of freezing to the urea pump assembly are substantially
eliminated through the heating configuration of the pump and/or
purging of urea solution from the urea pump assembly. Also,
clogging from urea crystals, corrosion, erosion or freezing damage
to valves or other components of the pump assembly are also reduced
due to the reduction of pumping pressures, urea solution purging
and/or elimination of typical pump valves and other components.
Still further, manufacturing costs are realized through a reduction
in components and reduction in complexity of the urea dispensing
pump assembly or urea dispensing system.
[0020] Further, exemplary embodiments provide improved, e.g.,
reduced heating and/or thawing time of urea solution, improved cold
starts particularly in cold climate, thereby minimizing urea
consumption through precise metering device, close loop control and
high precision urea dosing. Still other advantages include rapid
heating of the urea solution through the use of heat energy from an
associated internal combustion engine's coolant in conjunction with
electrical heaters, low fluid shear rate and fluid pressure
pulsation, positive displacement of the urea solution (due to the
flow being proportional with a rotational speed of the pump, which
allows precise flow control by speed adjustment), reduction or
elimination of valves, which eliminates common valve issues such as
clogging, deposit formation, corrosion or wear. Exemplary
embodiments of the pump also provides high viscosity and solid
contents capabilities, self-priming, reduction or elimination of
vapor or air lock, flexibility in operation and mounting, low noise
level, durability with respect to fluid abrasiveness, corrosive and
solids, flexible tubing provide increase volume of frozen urea
solution, seal-less pump eliminates urea leakage outside of the
system and lowers the cost (due to elimination of seals).
[0021] In general, referring to the drawings, exemplary embodiments
of the present invention are provided. The exemplary embodiments
provide a pump assembly 10 for delivery of a fluid, such as urea,
to an exhaust treatment system 12 having an exhaust treatment
device 13. The pump assembly includes a housing 14 defining a first
cavity 16 configured for receiving a first fluid, such as an engine
coolant, and a second cavity 18 configured for receiving a second
fluid, such as a urea solution. The first cavity includes a first
conduit 20 extending between a first inlet opening 22 and a first
outlet opening 24. The second cavity includes a second conduit 26
extending between a second inlet opening 28 and a second outlet
opening 30. The pump assembly further includes a pump 32 having
rotating and rotatably mounted actuator members 34 configured for
engaging the second conduit to cause movement of the second fluid
through the second conduit and hence second cavity. In the
embodiment shown, pump 32 actuator members 34 are exposed, but
opening 35 may optionally be closed by attachment of a suitable
cover (not shown).
[0022] In operation of the above exemplary embodiment, the pump
assembly receives the first fluid, such as coolant from an engine
coolant system 36 of an engine 38, for causing heating of the pump
assembly and a urea solution flowing through pump assembly 10. As
the housing is heated through flow of heated first fluid through
the first conduit, the heated housing thermally communicates with
both first and second conduits and in turn causes heating of the
urea solution flowing through the second conduit, which originates
from a urea supply 40. This heating may be supplemented through one
or more heaters 42 located at the second inlet opening 28, second
outlet opening 30 or both. Alternatively, the heaters may be
positioned on and in thermal communication with housing, first
conduit or second conduit. Movement of the urea solution through
the second conduit is achieved through one or more rotating
actuators member 34 of the pump 32, which are also rotatably
mounted. The one or more rotating actuator members are configured
to depress a portion of the second conduit along a portion of its
length (L) as it travels about an axis `A` of the pump. This
rotating and depressing or squeezing action causes fluid to flow in
a direction from the second inlet opening to the second outlet
opening, through conduit 43, and subsequently to an outlet 44, via
dosing module 45 or otherwise, which is in fluid communication with
an exhaust stream flowing through an exhaust system 46 of engine
38. The outlet may include a valve for controlling fluid flow, such
as a poppet valve or otherwise.
[0023] In more detail, with specific reference to FIGS. 2-5,
housing 12 is configured for receiving a first fluid for causing
heating to the housing, first conduit and second conduit, and
particularly fluids flowing through the second conduit. The housing
is also configured for receiving a second fluid for heating, and
further for causing movement of the second fluid to an outlet for
heating, for dispensing of the second fluid into an exhaust gas
stream. The housing is further configured for supporting components
of the pump assembly as described herein or otherwise.
[0024] In one exemplary embodiment, the first fluid is an engine
coolant and the housing is in fluid communication with an engine
coolant system for receiving coolant from an internal combustion
engine. In this configuration, the housing includes first cavity 16
having first conduit 20 extending between first inlet opening 22
and first outlet opening 24. The first cavity extends internally
but also about an exterior portion of the housing to allow for
other fluids and pump assembly components to be located within the
first cavity and optionally heated by the first fluid.
[0025] The housing further defines a first inlet connector 48 and a
first outlet connector 50 for fluidly connecting the first conduit
to coolant system 36. The first inlet and outlet connectors may
comprise any suitable connector for fluidly coupling components
together. Optionally, the inlet and/or outlet connector may include
or be in communication with one or more valves 52 for controlling
fluid flow through the first conduit and housing. For example, in
one exemplary embodiment the inlet and/or outlet include or are in
fluid communication with a poppet valve or the like. Optionally,
the one or more valves may be configured for providing fluid flow
to the housing or bypassing the housing (not shown) to effectively
fluidly disconnect the housing from the coolant system while still
maintaining fluid flow through the coolant system.
[0026] In one exemplary embodiment, the housing is in further fluid
communication with a urea supply and an exhaust system of an
internal combustion engine. In this embodiment, the housing
includes second cavity 18 having second conduit 26 extending
between second inlet opening 28 and second outlet opening 30. The
second conduit comprises a resilient flexible conduit configured to
be depressed along a length (L) thereof. In one particular
configuration, the flexible conduit is elastically depressible upon
application of suitable force and configured to return to an
original position after release of said suitable force. In
operation, the urea solution enters the housing and the second
cavity. Through the pump, a portion of the flexible conduit is
depressed. As the pump moves (e.g., actuators 34 rotate) the
portion of the flexible conduit being depressed moves towards the
second outlet effectively squeezing the fluid towards the second
outlet and the exhaust system.
[0027] In one exemplary embodiment, the flexible conduit is
separately formed from the housing and placed therein. In this
configuration, the flexible conduit extends from the second fluid
inlet to the second fluid outlet. The flexible conduit is also
arcuate in shape, and more specifically formed in a circular arc
about an axis of the pump and more particularly around the
rotatable actuating members of the pump. This orientation of the
flexible conduit about the axis of the pump allows the actuating
members of the pump, which also rotate about the axis of the pump,
to continuously engage the flexible conduit during rotation to
cause the above mentioned squeezing effect. The flexible conduit
may be formed of any suitable resilient material configured for
repeated application of force. For example, the flexible conduit
may be formed of a plastic, rubber, silicone or other flexible
resilient material.
[0028] Optionally, the housing may include additional suitable
connectors for coupling a conduit in fluid communication with urea
supply tank 38 to the pump assembly and for coupling the pump
assembly to a fluid discharge outlet, such as one or more outlets
44 of a dosing module 45. In one exemplary embodiment, the suitable
connectors are located proximate to the second inlet and second
outlet, respectively. Such suitable connectors may include any
suitable mechanical fastener such as threaded fasteners, other hose
or tube connectors or otherwise. Also, it is contemplated that one
or more valves may be located along the fluid flow path between the
pump assembly and the urea supply tank and/or between the urea pump
assembly and exhaust system for controlling fluid flow. The valves
52 may be electronically controlled valves in signal communication
with the controller such that they may be selectively opened or
closed by operation of the controller.
[0029] In one exemplary embodiment, the one or more outlets 44
comprise a portion of a dosing module 45 configured to provide
dispensing of the urea solution from the pump assembly to the
exhaust gas stream. In one configuration, the dosing module
consists of a two piece member forming a flanged housing assembly,
which includes a plurality of dosing poppet valves with an
individual electric heater, arranged in a circular pattern about
the exhaust gas flow and disposed at an angle, with respect to an
exhaust gas flow axis. The dosing module housing includes an
annular cavity that collects urea solution from a heated conduit of
the pump assembly and feeds the individual poppet valve. The
pressurized urea solution, or vaporized urea solution, transmits a
force on the back of the poppet valve that exceeds a spring force
of the valve for opening the valve for a time period for spraying a
metered quantity of urea, as determined by the control module using
data collected from the sensors. Each poppet valve has an
individual electric heater to maintain the urea solution in liquid
state or vaporize and deliver the urea solution into the exhaust
stream for cold starting. In one configuration, the pumping system
is located proximate to the exhaust system of an engine so as to
minimize the length of the piping between the pump outlet and the
dosing module
[0030] Also, the housing may further include one or more additional
fluid connectors for causing or effecting fluid flow through the
housing. This is particularly advantageous for removing fluid from
within the first or second cavities or conduits. For example, in
one exemplary embodiment the housing includes an additional inlet
port 54 in fluid communication with the second conduit for flushing
out fluid from within the second conduit. This is particularly
advantageous during periods of extreme cold where fluids used for
treatment of exhaust gas are prone to freezing. It should be
appreciated that the housing may also include an inlet port for
removal of fluid from within the first conduit in order to remove
the first fluid thereform. In ether configuration, flushing of the
first and/or second conduit may be achieved through an application
of air, or another other inert gas or by evacuating the conduits,
or otherwise.
[0031] It should be appreciated, as described therein, that the
housing may be formed or otherwise include additional components
for use with the pump system, exhaust treatment system or
otherwise. For example, the housing may be particularly formed or
include structure for forming electrical connectors for one or more
heaters, thermostats, pump motors or otherwise. Further, the
housing may include mounting features for mounting of the pump
assembly, such as to a engine component, vehicle component or
otherwise.
[0032] The housing may be formed of any suitable material. In one
exemplary embodiment, the material forming the housing is capable
of withstanding elevated temperatures such as temperatures commonly
experienced by engine coolant components. More specifically, the
housing is capable of withstanding temperatures in a range between
about 150.degree. F.-300.degree. F. or greater. Suitable materials
include metals, plastics, ceramics, combinations thereof or
otherwise. In one particular exemplary embodiment, the housing is
formed of metal. Similarly, the housing may be formed using any
suitable forming techniques. Examples of suitable forming
techniques include casting, molding, stamping, or otherwise. In one
particular exemplary embodiment, the housing is formed, at least in
part, through a casting process.
[0033] The pump assembly further includes a suitable pump 32 for
movement of fluid through the second conduit as described herein.
In one exemplary embodiment, the pump or components thereof (e.g.
actuators or otherwise) are at least partially located within the
housing and configured to engage the second conduit. In one
configuration, the pump includes an electric motor 56 including a
drive shaft 58 engaged with an actuation device 60 of the pump to
cause rotational movement of one or more actuators 34 attached
thereto. For example, in one configuration of the exemplary
embodiment, the pump comprises a peristaltic pump or the like. As
previously mentioned, the pump includes a rotational axis that is
generally concentric to that of an axis of the second conduit, or
otherwise adapted to maintain the pressing squeezing engagement
between the actuators 34 and the second conduit 26. In another
configuration, except for a motor, substantially all of the pump
assembly components are located within the housing. In yet another
configuration, all the pump assembly components may be located
within the housing. This concentric configuration provides the
ability of the rotating actuators to apply a uniform force profile
and deflection to the second conduit to cause movement of fluid
therethrough.
[0034] The motor is connected to the drive shaft to transfer
rotational movement thereto and includes suitable connectors 63 for
connection to a controller, power source or otherwise. In one
exemplary embodiment the motor comprises a rotational motor
configured to cause rotation of the drive shaft and hence actuators
at a rate between about 10 rpm-200 rpm or greater. However, other
rotational speeds are contemplated. It should be appreciated that
the rotational speed of the motor, drive shaft and actuators may be
based upon the amount of deflection of the second conduit and more
specifically the potential fluid flow through the second conduit as
a result of a fluid flow restriction moving along the length of the
second conduit. In other words, it is contemplated that the greater
the deflection of the second conduit by the actuators, the lower
the rotational speed may be for a given fluid output. Conversely, a
lower amount of deflection to the second conduit by the actuators
may require an increased motor speed to obtain given fluid
output.
[0035] The motor 56 may be configured to rotate clockwise,
counterclockwise or both, to move between the second inlet and
outlet. Thus the direction of flow of the fluid may be reversed by
reversing the direction of the rotation of the pump motor. This may
be used to purge a portion of the second conduit when the urea
solution is not needed, such as when the vehicle engine is turned
off, which may be improved upon through one or more valves (e.g.,
check valve, solenoid valve or otherwise) located downstream from
the pump and openable to the atmosphere to offset negative
pressure. In one exemplary embodiment, the motor rotates or causes
rotation of the drive shaft, actuation device or actuators in a
direction towards the second outlet. Also, rotational speed of the
motor or attached components may be generally constant or variable.
In one exemplary embodiment, the speed of the motor, actuator
device and/or actuators are based upon the required urea solution
to be delivered to the exhaust treatment device to maintain
efficiency thereof. Examples of suitable motors include metering
pumps such as jacketed peristaltic metering pumps. However, the use
of other pumps is possible.
[0036] The actuator device 60 is fixedly connected to the drive
shaft 58 through suitable connection means such as an interface
fit, splined or keyed joint between the device and the shaft, or a
combination thereof or otherwise. In the exemplary embodiment
shown, the actuator device comprises a base member 62, which may be
a circular shape, having actuators 34 mounted to an outer mounting
portion or boss 64 thereof. The actuator 34 is in the form of a
journaled wheel or shaft which in one exemplary embodiment is
rotatably mounted. Optionally, actuators 34 may be formed as a part
of the base member 62 as a lobe or cam-shaped protrusion. The
actuator device may include a number of actuators, which may be
based on, in part, a desired flow rate through the second conduit.
It is contemplated that the number of actuators on the actuator
device may include between about 1-4 or more actuators. It is
further contemplated that the actuators may be evenly spaced apart
to maintain balance forces on the shaft, base member and actuator
device during rotation.
[0037] The actuators 34 are mounted to the actuator device through
suitable attachment means and include at least a portion that
extends beyond the outer periphery of the actuator device. In one
exemplary embodiment, the actuators comprise rollers that are
rotatably mounted to the actuator device. The rotatable mounting of
the actuators may be achieved through pivot connections which may
include one or more bearing members 67, or otherwise, for providing
rotatable mounting and reduced friction. Further, the actuator
device, actuators or otherwise may be formed of or include a
friction reducing material.
[0038] Optionally, in one exemplary embodiment, the pump assembly
includes one or more resistance heaters 42 for heating the urea
solution. Such heaters may be particularly advantageous for raising
the temperature of the urea solution prior to the temperatures of
the first fluid and/or housing reaching optimum temperatures for
heating the urea solution. Also, this may be particularly
advantageous during cold start of the engine or exhaust treatment
system of the pump assembly to melt or otherwise heat urea solution
within the second cavity. In one configuration, the housing
includes an additional resistance heater 42 located at the second
inlet opening, the second outlet opening or both. The one or more
additional heaters may be located upstream and/or downstream from
the housing. The additional heater includes electrical connections
for attaching electrical power to the additional heater.
[0039] In one exemplary embodiment, the heater is in power or
signal communication with a controller, as described herein, to
control an application and/or amount of power (e.g., current) to
the additional heaters. Communication between the controller and
the heater is achieved through suitable electrical connectors 63
which may be in power or signal communication with a controller,
power supply or otherwise.
[0040] In one exemplary embodiment, the heater comprises a coiled
electrical resistance heater configured to heat the housing located
at or approximate to the inlet opening and/or outlet opening. In
the configuration shown, the coiled electrical resistance heater is
wrapped about the second inlet and outlet openings. In another
configuration, the heater comprises a resistance heater configured
to heat the urea solution directly, within the urea fluid flow. In
yet another configuration, the heater comprises a non-resistance
heater such as heated air, an induction heater, microwave
radiation, radio waves, ultrasonic energy, infrared energy or
other. Other electrical and non-electrical heating configurations
are contemplated.
[0041] Optionally, the pump assembly further includes one or more
temperature sensors 64 for measuring the temperature of the
additional heaters, first fluid, urea solution or a combination of
them. In the configuration shown, the temperature sensors are
located proximate to the second inlet opening, outlet opening or
both for determining the temperature of urea solution entering or
exiting the pump housing or both. However, it is contemplated that
the additional temperature sensors may be located further upstream
or downstream from the pump assembly. As with the heaters, in one
exemplary embodiment the one or more temperature sensors include a
connector 65 for signal communication with another component, such
as a controller or otherwise. Accordingly, it is contemplated that
the temperature sensed by the temperature sensors may be used to
determine whether the additional heaters are used based upon the
urea solution temperature, the temperature of the coolant or
otherwise.
[0042] In one exemplary embodiment, the pump assembly and
components associated therewith are in communication with a
controller 66, such as power or signal communication. The
controller may be configured to communicate with and/or control
functions of the pump assembly and components thereof. For example,
the controller may be in power or signal communication with the
motor for controlling rotational direction and speed of the
actuators. The controller may be in power or signal communication
with any of the valves described herein for controlling fluid flow
through the pump assembly or otherwise. The controller may be in
power or signal communication with the temperature sensors or
heaters as described herein for controlling additional heating to
the urea solution. It should be appreciated that the controller may
be configured to communicate with or control other components of,
or related to, the pump assembly.
[0043] In one exemplary embodiment, the controller receives and
stores information transmitted by sensors of the pump assembly,
such as temperature sensors, pressure sensors, NO.sub.X sensors or
otherwise. With this information, the controller continuously
calculates the appropriate urea injection rate and timing of the
injection. Further the controller adjusts the urea temperature and
flow to maintain a precise metered quantity of urea being delivered
into an exhaust gas stream, via one or more poppet valves of a
dosing module 45 or otherwise. The flow is adjusted by modifying
the pump speed that delivers the quantity (e.g., volume) of fluid
proportional with the pump speed, hence a positive displacement
pump. The pump delivers controlled flow at a relatively high
pressure for better fluid atomization (or vapor mixing) in the
exhaust gas stream. The control module is also configured to adjust
the heater temperature, control the function of a urea supply
heater, such as a urea cartridge microwave heater, that melts
frozen urea and allows the urea to flow to the pump assembly. The
controller also provides an alert signal when a fluid level sensor,
such as an ultrasonic level sensing, in the urea supply cartridge
detects low levels of urea solution. It should be appreciated that
the controller may be configured to control additional aspects of
fluid dispensing or dosing or may be configured to control
dispensing or dosing in different manners.
[0044] The controller may comprise a stand alone controller or form
a portion of a more encompassing controller. For example, the
controller may be associated with a controller for the emissions
control system of the engine. Further, in one particular
application, the controller may form a portion of the electronic
control module of a vehicle. Other configurations are
contemplated.
[0045] Exemplary embodiments of the pump assembly of the present
invention may be utilized in a variety of applications. For
example, the pump assembly may be used with practically any
emission producing device including stationary and non-stationary
applications. In one particular configuration, exemplary
embodiments of the pump assembly may be used with internal
combustions engines.
[0046] In one more particular configuration, exemplary embodiments
of the pump assembly may be used with vehicle engines, and more
particularly, diesel engines. It should be appreciated that the
teachings described herein can be used in numerous emission
reducing applications.
[0047] Referring to FIG. 1, an exemplary embodiment of an exhaust
treatment system 12 is provided. The exhaust treatment system
includes a pump assembly in fluid communication with a coolant
system of an engine 38 for causing heating of the pump assembly and
fluid flowing therethrough. The pump assembly is in further
communication with a urea supply 40 and one or more outlets 44 of a
dosing module 45 in fluid communication with an exhaust gas stream.
As the coolant travels through the pump assembly, heat generated by
the coolant from an engine is absorbed by the pump assembly and the
urea solution flowing through the pump assembly. The pump causes
the urea to be pumped from the urea supply to the outlet whereby
heat from the coolant heats the urea solution. Optionally, the urea
solution is further heated by one or more additional heaters 42.
The exhaust treatment system is controlled through a controller for
metering the flow rate of urea through the pump and optionally
coolant through the pump to ensure that a suitable supply of urea
is pumped into an exhaust gas stream flowing to an exhaust
treatment device 13.
[0048] Referring to FIGS. 2-5, exemplary embodiments of pump
assemblies 10 are provided. The pump assemblies include a first
cavity 16 in fluid communication with a coolant system of an
engine. Coolant from the coolant system enters first inlet opening
22 and travels along first conduit 20 to eventually exit through
first outlet opening 24. The pump assemblies further includes a
second cavity 18 in fluid communication with a urea supply 40. The
urea is pumped through the housing and to an outlet in fluid
communication with an exhaust gas stream through pump 32. This is
achieved through the direct displacement of urea through the second
conduit by rotating actuators 34 squeezing and forcing urea
solution from the second inlet opening 28 to the second outlet
opening 30 and eventually to the outlet 44. During the coolant's
travel along the first conduit heat is absorbed by housing 14,
which is further absorbed by the urea solution flowing through the
housing and second conduit.
[0049] Exemplary embodiments of the present invention further
contemplate a method of heating a urea solution for delivery to an
exhaust treatment system 13. The method includes fluidly coupling a
urea pump assembly 10 to a coolant system of an engine 38 to
provide an engine coolant flow through the urea pump assembly. The
pump assembly is further fluidly coupled to a urea solution supply
to provide a urea solution to the urea pump assembly. A motor 56 of
the pump assembly 10 is activated through a suitable controller 66.
Upon activation, the motor causes rotation of an actuation device
60 having a plurality of rotatably mounted actuators 34. As the
actuators engage a conduit receiving the urea solution it squeezes
the conduit causing the urea solution to travel through the housing
and to an outlet in fluid communication with an exhaust gas stream.
During movement of the urea solution through the urea pump
assembly, the urea solution is heated by the engine coolant.
[0050] 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.
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