U.S. patent application number 14/045186 was filed with the patent office on 2015-04-09 for system, apparatus, and methods for performing a quality diagnostic of an aqueous urea solution.
This patent application is currently assigned to Cummins Emission Solutions Inc.. The applicant listed for this patent is Cummins Emission Solutions Inc.. Invention is credited to Eric B. Andrews.
Application Number | 20150096285 14/045186 |
Document ID | / |
Family ID | 52775828 |
Filed Date | 2015-04-09 |
United States Patent
Application |
20150096285 |
Kind Code |
A1 |
Andrews; Eric B. |
April 9, 2015 |
SYSTEM, APPARATUS, AND METHODS FOR PERFORMING A QUALITY DIAGNOSTIC
OF AN AQUEOUS UREA SOLUTION
Abstract
System, apparatus, and methods are disclosed for enabling a
quality diagnostic of an aqueous urea solution (AUS) of an exhaust
system when the AUS is outgassed. Systems, apparatus, and methods
are also disclosed for disabling an output of a quality condition
of the AUS in response at least in part to detecting that an AUS
fill event of an AUS storage tank has occurred.
Inventors: |
Andrews; Eric B.; (Carmel,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cummins Emission Solutions Inc. |
Columbus |
IN |
US |
|
|
Assignee: |
Cummins Emission Solutions
Inc.
Columbus
IN
|
Family ID: |
52775828 |
Appl. No.: |
14/045186 |
Filed: |
October 3, 2013 |
Current U.S.
Class: |
60/286 ;
73/114.69 |
Current CPC
Class: |
F01N 2610/142 20130101;
F01N 2610/10 20130101; F01N 2610/148 20130101; F01N 11/00 20130101;
Y02T 10/47 20130101; Y02T 10/40 20130101 |
Class at
Publication: |
60/286 ;
73/114.69 |
International
Class: |
F01N 11/00 20060101
F01N011/00 |
Claims
1. A method, comprising: determining that an aqueous urea solution
(AUS) confined in a storage tank that is connected to an exhaust
system is outgassed; in response to the determining the AUS is
outgassed, performing an AUS diagnostic comprising operating a
quality sensor to determine a urea concentration of the AUS;
wherein the operating the urea quality sensor comprises
ultrasonically determining a fluid density of the AUS.
2. The method of claim 1, further comprising, in response to
determining the AUS is not outgassed, disabling the performing the
AUS diagnostic.
3. The method of claim 2, further comprising, in response to
determining the AUS is not outgassed, operating a heater to
increase a temperature of the AUS.
4. The method of claim 3, wherein the operating the heater
comprises heating the AUS according to at least one operation
selected from the operations consisting of: heating the AUS for at
least 30 minutes, heating the AUS to a temperature rise of at least
30.degree. C., and heating the AUS to a temperature of at least
45.degree. C.
5. The method of claim 3, wherein the operating the heater
comprises opening a heat exchange valve in a heat exchange system
that receives heat from operation of an internal combustion
engine.
6. The method of claim 1, wherein the determining that the AUS
confined in the storage tank is outgassed comprises determining
whether the AUS has experienced a sufficient temperature rise since
a most recent AUS fill event of the storage tank, wherein the
sufficient temperature rise comprises at least one event selected
from the events consisting of: being heated for at least 30
minutes, being heated to a temperature at least 30.degree. C. above
a fill temperature, and being heated to a temperature of at least
45.degree. C.
7. A method, comprising: detecting a fill event of a storage tank
for storing an aqueous urea solution (AUS); disabling a quality
diagnostic of the AUS after detecting the fill event; and
outgassing the AUS before enabling the quality diagnostic.
8. The method of claim 7, after outgassing the AUS, performing an
AUS diagnostic comprising operating a quality sensor to determine a
urea concentration of the AUS; wherein the operating the urea
quality sensor comprises ultrasonically determining a fluid density
of the AUS.
9. The method of claim 8, wherein outgassing the AUS includes at
least one operation selected from the operations consisting of:
heating the AUS for at least 30 minutes, heating the AUS to a
temperature rise of at least 30.degree. C., and heating the AUS to
a temperature of at least 45.degree. C.
10. The method of claim 8, wherein heating the AUS comprises
opening a heat exchange valve of a heat exchange circuit to
circulate a heat exchange fluid that is heated by operation of an
internal combustion engine to the storage tank.
11. The method of claim 7, wherein detecting the fill event
comprises determining whether an AUS level in the storage tank has
increased since a last known fill level detection.
12. An apparatus, comprising: an electronic controller connected to
an aqueous urea solution (AUS) storage tank level sensor and an AUS
quality sensor associated with an AUS storage tank for providing
AUS to an exhaust system, wherein the controller is further
connected to a heating device and includes: a storage tank level
determination module configured to detect a fill event of AUS in
the storage tank; a quality determination module configured to
determine a quality of the AUS in the storage tank and output a
quality condition associated with the quality of the AUS; and an
AUS outgassing module configured to disable output of the quality
condition by the quality determination module upon the detection of
the fill event by the storage tank level determination module,
where the AUS outgassing module is further configured to control
the heating device to increase a temperature of the AUS a
predetermined amount before enabling output of the quality
condition by the quality determination module.
13. The apparatus of claim 12, wherein the heating device includes
a heat exchange circuit that provides a flow of heating fluid to
the storage tank for heating of the AUS.
14. The apparatus of claim 12, wherein the quality determination
module is configured to output to a display an indication of the
AUS quality.
15. A system, comprising: an internal combustion engine including
an exhaust system; a dosing system connected to the exhaust system
to provide an aqueous urea solution (AUS) to the exhaust system; a
storage tank for storing AUS connected to the dosing system,
wherein the storage tank includes a level sensor operable to
indicate a level of AUS in the storage tank, a quality sensor
operable to indicate a quality condition of the AUS in the storage
tank, and a temperature sensor operable to indicate a temperature
of the AUS in the storage tank; a heat exchange system configured
to heat the AUS; and a controller connected to the heat exchange
system that is operable to control heating of the AUS in the
storage tank, wherein the controller is configured to suspend an
output of the indication of the quality condition of the AUS and
increase a temperature of the AUS a predetermined amount in
response at least in part to an indication from the level sensor
that the level of AUS in the storage tank has increased.
16. The system of claim 15, wherein the heat exchange system
defines a flow path that is arranged to circulate a heat exchange
fluid to thermally contact heated heat exchange fluid with the AUS
in the storage tank, wherein the heat exchange system further
includes a control valve in the flow path to control a flow of the
heat exchange fluid in the flow path.
17. The system of claim 16, wherein the controller is configured to
initiate a circulation period of the heated heat exchange fluid in
the flow path through the storage tank to increase the temperature
of the AUS in the storage tank the predetermined amount.
18. The system of claim 17, wherein the predetermined amount
includes at least one of the AUS being heated to a temperature
threshold, an increase in temperature of the AUS by a predetermined
amount, and a heating the AUS at a predetermined temperature for a
length of time.
Description
BACKGROUND
[0001] The present application generally relates to an aqueous urea
solution (AUS) in internal combustion engine diesel exhaust
systems, and more particularly, but not exclusively, to integrating
diesel exhaust systems in vehicles.
[0002] Modern systems that include internal combustion engines
often include a selective catalytic reduction (SCR) exhaust
aftertreatment system to control exhaust system emissions. SCR
systems typically include an AUS storage tank connected to a doser
that injects AUS into the exhaust stream to reduce NOx emissions.
Under normal operating conditions, AUS will become depleted from
the storage tank and requires periodic re-filling of the storage
tank.
[0003] An ultrasonic technology quality sensor in the AUS storage
tank can be used to measure the fluid density of the AUS to
ascertain the concentration quality. However, when AUS is added to
the storage tank, potential complications in detecting the quality
of the AUS are introduced. Newly added AUS typically stores
dissolved gas in the fluid, and micro-bubbles are formed in the AUS
when the AUS during operation of the system. This heating causes
the dissolved gas to vaporize, resulting in an apparent change to
the AUS's physical properties. This apparent physical property
change disrupts the speed of sound through the AUS, thereby
resulting in incorrect AUS concentration quality readings when
using an ultrasonic technology sensor. An incorrect concentration
quality reading may result in the system responding in a manner
that is detrimental to operation of the engine or the dosing
system. As a result of the incorrect quality reading, for example,
power to the engine can be reduced or the engine unable to be
started altogether. Therefore, a need remains for further
improvements in systems, apparatus, and methods for performing a
quality diagnostic of an AUS in exhaust aftertreatment systems.
SUMMARY
[0004] One embodiment is a unique system, method, and apparatus to
determine the outgassed, or offgassed, state of an aqueous urea
solution (AUS) in an internal combustion engine diesel exhaust
system before enabling a quality diagnostic of the AUS. Other
embodiments include unique methods, systems, and apparatus to
detect an AUS fill event in an AUS storage tank and to control the
performance of an AUS quality diagnostic in view thereof. This
summary is provided to introduce a selection of concepts that are
further described below in the illustrative embodiments. This
summary is not intended to identify key or essential features of
the claimed subject matter, nor is it intended to be used as an aid
in limiting the scope of the claimed subject matter. Further
embodiments, forms, objects, features, advantages, aspects, and
benefits shall become apparent from the following description and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a schematic illustration of a system including an
exemplary engine and AUS dosing system.
[0006] FIG. 2 is a diagram illustrating an exemplary controller
apparatus for controlling an AUS quality diagnostic.
[0007] FIG. 3 is a flow diagram of a procedure that can be
performed in conjunction with an AUS quality diagnostic.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0008] For the purposes of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended, any alterations and further modifications in the
illustrated embodiments, and any further applications of the
principles of the invention as illustrated therein as would
normally occur to one skilled in the art to which the invention
relates are contemplated herein.
[0009] With reference to FIG. 1, there is illustrated an exemplary
system 100 for heating an aqueous urea solution (AUS) that is
delivered to an exhaust system 106 of an engine 102 via a dosing
system 120. AUS stored in an AUS storage tank 132 is delivered to
an aftertreatment system 126 of an engine 102 from an AUS dosing
system 120. System 100 may be provided on a vehicle powered by an
engine 102 such as a diesel engine, or on an engine 102 utilized in
other applications such as power generation or pumping systems.
Engine 102 includes an intake system 104 through which charge air
enters and an exhaust system 106 through which exhaust gas
resulting from combustion exits, it being understood that not all
details of these systems that are typically present are shown.
Engine 102 includes a number of cylinders forming combustion
chambers into which fuel is injected by fuel injectors to combust
with the charge air that has entered through intake system 104. The
energy released by combustion powers the engine 102 via pistons
connected to a crankshaft. When used to propel a vehicle, engine
102 is coupled through a drivetrain to drive wheels that propel the
vehicle. Intake valves control the admission of charge air into the
cylinders, and exhaust valves control the outflow of exhaust gas
through exhaust system 106 and ultimately to atmosphere. Before
entering the atmosphere, however, the exhaust gas is treated by one
or more aftertreatment devices in an aftertreatment system 126.
[0010] In one example, the exhaust system 106 includes an
aftertreatment system 126 having one or more selective catalytic
reduction (SCR) catalysts 128 and one or more locations for
receiving an AUS from AUS dosing system 120. The aftertreatment
system 126 may include one or more other aftertreatment components
not shown, such as one or more oxidation catalysts, one or more
particulate filters, an ammonia oxidation catalyst, and various
temperature, pressure and exhaust gas constituent sensors. Exhaust
system 106 may also include various components not shown, such an
exhaust gas recirculation system, a turbocharger system, coolers,
and other components connecting exhaust system 106 to intake system
104. An AUS injector 124 is mounted on a portion of exhaust system
106 upstream of SCR catalyst 128 with its outlet, or nozzle,
arranged to spray AUS into the exhaust system 106 where it mixes
with engine exhaust gas produced by engine 102. SCR catalyst 128
promotes a chemical reaction between the AUS and NOx in the exhaust
gas that converts substantial amounts of NOx to reduce NOx
emissions before the exhaust gas passes into the atmosphere.
[0011] Dosing system 120 receives AUS from an AUS storage tank 132
and provides the AUS to the exhaust system 106 via an injector 124
or other structure for injection or delivery to a decomposition
chamber or directly to the exhaust system 106. The flow of AUS
through injector 124 can controlled by a dosing system two-way
control valve 122 or other structure for toggling or limiting AUS
flow to the injector 124. As used herein, injector includes any
nozzle, static device, electronically controllable device, and/or
mechanical actuator that provide an outlet for reductant delivery.
One example of an AUS is a diesel exhaust fluid (DEF) which
comprises a solution of 32.5% high purity urea and 67.5% deionized
water. It shall be appreciated, however, that other aqueous urea
solutions may also be utilized.
[0012] Dosing system 120 may include various structures to
facilitate receipt of AUS from an AUS storage tank 132 and the
delivery of the AUS to the exhaust system 106. For example, a
dosing system may include a pump and a filter screen and a check
valve upstream of the pump to receive AUS from the AUS storage tank
132.
[0013] AUS storage tank 132 holds a supply of AUS and is vented to
allow AUS to be withdrawn at an outlet port 134. When dosing system
124 operates, it draws AUS from AUS storage tank 132 and pumps the
AUS through conduit 136 to injector 124. A backflow conduit (not
shown) may be provided to return excess AUS to AUS storage tank
132.
[0014] In certain embodiments, the system 100 further includes a
controller 160 structured to perform certain operations to receive
and interpret signals from an AUS temperature sensor 152, an AUS
storage tank 132 level sensor 154, and an AUS quality sensor 156,
which can be position inside the tank 132. In certain embodiments,
the controller forms a portion of a processing subsystem including
one or more computing devices having memory, processing, and
communication hardware. The controller may be a single device or a
distributed device, and the functions of the controller may be
performed by hardware or software.
[0015] Engine 102 further comprises a heat exchange system 140
through which a heat exchange fluid, such as engine coolant, is
circulated by a pump 108. A conduit 114 forms at least a portion of
a heat exchange circuit 142 that defines a flow path for the heated
heat exchange fluid to flow though dosing system 120 and AUS
storage tank 132 to heat AUS therein by providing thermal contact
of the heat exchange fluid with the AUS located in AUS storage tank
132. Heat exchange system 140 receives heat from a heat source,
such as engine 102, that heats the heat exchange fluid in or before
it enters heat exchange circuit 142. Heat exchange system 140 may
be part of the cooling system for engine 102 that is connected to a
radiator (not shown) that receives and rejects heat generated by
operation of engine 102. Other embodiments contemplate heat sources
other than or in addition to engine 102, such as the exhaust
system, an electric heater, or other source of heat that maintains
or rapidly heats the heat exchange fluid for use in heating AUS.
Furthermore, it is contemplated that fluids other than liquid
coolant may be used as the heat exchange fluid.
[0016] In the illustrated embodiment, the continuous flow path
defined by the heat exchange circuit 142 extends from an outlet 110
of pump 108 to a storage tank inlet 136 of AUS storage tank 132,
and through AUS storage tank 132. A return portion 144 of the flow
of the conduit 114 path extends from the second storage tank outlet
138 of the AUS storage tank 132 to the inlet 112 of pump 108 and
includes, for example, a heat exchange two-way control valve 116 in
the flow path between the outlet 138 of AUS storage tank 132 and
the inlet 112 of pump 112. Conduit 114 may be comprised of a single
continuous conduit or multiple conduits through AUS storage tank
132, or of discrete segments connected to inlets and outlets of AUS
storage tank 132, with channels, conduits or other structures that
provide a continuation of the flow path therethrough.
[0017] The flow of heat exchange fluid in heat exchange circuit 136
may be controlled and monitored by controller 160 such as an engine
control module (ECM) or a doser control module (DCM). It shall be
appreciated that the controller or control module may be provided
in a variety of forms and configurations including one or more
computing devices forming a whole or part of a processing subsystem
having non-transitory memory storing computer executable
instructions, processing, and communication hardware.
[0018] Controller 160 is in communication with any component of the
system 100 to gather information and provide commands. In FIG. 1,
controller 160 is operatively coupled with and configured to store
instructions in a memory which are readable and executable by
controller 160 to operate heat exchange control valve 116 to
complete one or more heat exchange cycles that heat an AUS in AUS
storage tank 132. Controller 160 is further operatively coupled
with and may receive a signal from AUS temperature sensor 152, AUS
level sensor 154, and AUS quality sensor 156 associated with AUS
storage tank 132. AUS temperature sensor 152 is operable to provide
a signal indicating the temperature of the AUS in AUS storage tank
132. AUS level sensor 154 is operable to provide a signal
indicating the level of the AUS in AUS storage tank 132. AUS
quality sensor 156 is operable to provide a signal indicating the
quality of the AUS in AUS storage tank 132. AUS temperature sensor
152, AUS level sensor 154, and AUS quality sensor 156 need not be
in direct communication with AUS storage tank 132, and can be
located at any position within AUS outgassing system 130 that
provides a suitable indication of applicable AUS readings in AUS
storage tank 132.
[0019] In FIG. 1, controller 160 is further connected to dosing
system 120, dosing system two-way control valve 122, heat exchange
two-way control valve 116, and an AUS quality fault output 158. AUS
quality fault output 158 can be any suitable device for displaying
a result of the AUS quality diagnostic to a user, operator, service
technician, or other party, and can include an indicator lamp, a
gauge, a printer, a memory device, an audible alarm, and/or other
suitable output device.
[0020] The controller 160 includes stored data values, constants,
and functions, as well as operating instructions stored on computer
readable medium. Any of the operations of exemplary procedures
described herein may be performed at least partially by the
controller. The description herein including modules emphasizes the
structural independence of the aspects of the controller 160, and
illustrates one grouping of operations and responsibilities of the
controller 160. Other groupings that execute similar overall
operations are understood within the scope of the present
application. Modules may be implemented in hardware and/or software
on computer readable medium, and modules may be distributed across
various hardware or software components. More specific descriptions
of certain embodiments of controller operations are included in the
section referencing FIG. 2. Operations illustrated are understood
to be exemplary only, and operations may be combined or divided,
and added or removed, as well as re-ordered in whole or part,
unless stated explicitly to the contrary herein.
[0021] Certain operations described herein include operations to
interpret one or more parameters. Interpreting, as utilized herein,
includes receiving values by any method known in the art, including
at least receiving values from a datalink or network communication,
receiving an electronic signal (e.g., a voltage, frequency,
current, or PWM signal) indicative of the value, receiving a
software parameter indicative of the value, reading the value from
a memory location on a computer readable medium, receiving the
value as a run-time parameter by any means known in the art, and/or
by receiving a value by which the interpreted parameter can be
calculated, and/or by referencing a default value that is
interpreted to be the parameter value.
[0022] One exemplary embodiment of controller 160 is shown in FIG.
2. In certain embodiments, the controller 160 includes an AUS
quality input 172 that is received as a signal from AUS quality
sensor 156, an AUS level input 182 that is received as a signal
from AUS level sensor 154, and an AUS temperature input 192 that is
received as a signal from AUS temperature sensor 152. In certain
embodiments, the controller 160 includes one or more modules
structured to functionally execute the operations of the controller
160 in response to the inputs 172, 182, and 192.
[0023] Controller 160 includes an AUS quality module 170 that
receives and interprets the AUS quality input 172. AUS quality
module 170 is configured to output an AUS quality condition 174
that indicates a quality of the AUS in AUS storage tank 132. When a
fault condition of the AUS quality is determined, operation of
engine 102 may be derated or other system impacting restraint may
be initiated to limit operation with AUS that is not of a
predetermined or desired quality.
[0024] The controller 160 further includes an AUS storage tank
level module 180 that receives and interprets AUS level input 182.
The AUS level input provides an indication of the AUS level in AUS
storage tank 132. AUS storage tank level module 180 is configured
to provide a tank fill level indication 184 when a comparison of
AUS level input 182 signals indicates an AUS storage tank 132 fill
event has occurred, which indicates dissolved gasses are present in
the AUS in AUS storage tank 132 which is detrimental to AUS quality
determination.
[0025] Controller 160 also includes an AUS outgassing module 190
that receives and interprets an AUS temperature input 192.
Furthermore, the AUS outgassing module 190 interprets a tank fill
indication 184 from the AUS storage tank level module 180. When a
tank fill indication 184 indicates a re-fill or filling event of
storage tank 132 has occurred, AUS outgassing module suspends
operation of an AUS quality determination by AUS quality module 170
and performs an operation such as providing an AUS heating command
196 to outgas the AUS in storage tank 132. In one embodiment, in
response to AUS heating command 196, controller 160 provides a
signal to open heat exchange valve 116 to initiate circulation of
the heat exchange fluid to heat the AUS in AUS storage tank 132,
which vaporizes the dissolved gas in the AUS so that an accurate
AUS quality input 172 can be provided.
[0026] AUS outgassing module 190 is further configured to provide
an AUS quality determination command 194 to enable a determination
of the quality of the AUS when the AUS heating operation initiated
by AUS heating command 196 is satisfied. In one embodiment,
satisfaction of AUS heating command 196 is determined by AUS
temperature input 192 indicating a predetermined temperature
increase of the AUS in AUS storage tank 132, the temperature of the
AUS in AUS storage tank 132 reaching a predetermined temperature
differential threshold 191, by providing heating for a
predetermined amount of time, or other outgassing indication. The
AUS quality determination command 194 is interpreted by the AUS
quality module 170 to enable providing of AUS quality condition 174
from AUS quality input 172. In certain embodiments, the controller
160 and/or the AUS outgassing module 190 contain a timer mechanism
(not shown) operable in conjunction with AUS temperature input 192
for interpreting an outgassing period or providing an outgassed
indication.
[0027] The schematic flow diagram in FIG. 3 and related description
which follows provides an illustrative embodiment of performing
procedures for enabling a quality diagnostic based on an AUS
outgassing determination. Operations illustrated are understood to
be exemplary only, and operations may be combined or divided, and
added or removed, as well as re-ordered in whole or part, unless
stated explicitly to the contrary herein. Certain operations
illustrated may be implemented by a computer executing a computer
program product on a non-transient computer readable storage
medium, where the computer program product comprises instructions
causing the computer to execute one or more of the operations, or
to issue commands to other devices to execute one or more of the
operations.
[0028] With reference to FIG. 3, there is illustrated a flow
diagram of an exemplary procedure 200 for enabling a quality
diagnostic that is put in operation by programming into controller
160 for use in, for example, system 100. Procedure 200 begins at
operation 202 in which a control routine for enabling an AUS
quality diagnostic is started. Operation 202 can begin by
interpreting a key-on event and/or by initiation by an operator or
technician. Operation 202 may alternatively or additionally include
interpreting a communication or other parameter indicating that
operation of the AUS quality determination is going to resume after
an AUS outgassing procedure. Procedure 200 proceeds at operation
204, where the AUS level in storage tank 132 is interpreted. From
operation 204, procedure 200 proceeds at conditional 206 where it
is determined whether a storage tank fill event has occurred since
the AUS was last outgassed. If conditional 206 is negative,
procedure 200 proceeds at operation 212 where an AUS quality
diagnostic is performed until a termination condition at 214.
[0029] If conditional 206 is affirmative, procedure 200 continues
at conditional 208 where it is determined whether the AUS is
outgassed. In one embodiment, the determination whether the AUS is
outgassed includes determining whether the AUS has experienced a
sufficient temperature rise to outgas the AUS since a most recent
AUS fill event of the storage tank. In certain embodiments, the
sufficient temperature rise can include the AUS being heated at a
certain temperature for at least 30 minutes, being heated to a
temperature at least 30.degree. C. above a fill temperature, and
being heated to a temperature of at least 45.degree. C. If
conditional 208 is affirmative, procedure 200 proceeds at operation
212 where an AUS quality diagnostic is performed until a
termination condition at 214.
[0030] If conditional 208 is negative, procedure 200 proceeds at
operation 210 to outgas the AUS before enabling the AUS quality
diagnostic. In one embodiment of operation 210, the AUS in AUS
storage tank 132 is heated until a termination condition is reached
which indicates the AUS is outgassed, or until another heat cycle
is initiated at conditional 208. Procedure 200 then continues as
discussed above to complete one or more cycles at operation 210 to
heat the AUS by, for example, circulation of the heat exchange
fluid until the AUS in the storage tank has been outgassed.
[0031] In certain embodiments, the AUS in AUS storage tank 132 is
determined to be outgassed when the AUS reaches a predetermined
temperature T.sub.x, has been heated to increase in temperature by
a predetermined temperature differential threshold T.sub.th 191,
and/or has been maintained at a predetermined threshold temperature
for a predetermined period of time t.sub.x. In certain specific
embodiments, the AUS is outgassed by at least one of the following:
heating the AUS for at least 30 minutes, heating the AUS to a
temperature rise of at least 30.degree. C., and heating the AUS to
a temperature of at least 45.degree. C.
[0032] Various aspects of the systems, apparatus, and methods
disclosed herein. For example, one aspect involves a method that
includes determining that an aqueous urea solution AUS confined in
a storage tank that is connected to an exhaust system is outgassed
and, in response to the determining the AUS is outgassed,
performing an AUS diagnostic comprising operating a quality sensor
to determine a urea concentration of the AUS. Operating the urea
quality sensor comprises ultrasonically determining a fluid density
of the AUS.
[0033] In one embodiment, the method includes, in response to
determining the AUS is not outgassed, disabling the performing the
AUS diagnostic. In one refinement, the method includes, in response
to determining the AUS is not outgassed, operating a heater to
increase a temperature of the AUS. In a further refinement of the
method, operating the heater includes heating the AUS according to
at least one operation selected from the operations consisting of:
heating the AUS for at least 30 minutes, heating the AUS to a
temperature rise of at least 30.degree. C., and heating the AUS to
a temperature of at least 45.degree. C. In another refinement of
the method, the operating the heater includes opening a heat
exchange valve in a heat exchange system that receives heat from
operation of an internal combustion engine. In another embodiment
of the method, determining that the AUS confined in the storage
tank is outgassed includes determining whether the AUS has
experienced a sufficient temperature rise since a most recent AUS
fill event of the storage tank. The sufficient temperature rise can
include at least one event selected from the events consisting of:
being heated for at least 30 minutes, being heated to a temperature
at least 30.degree. C. above a fill temperature, and being heated
to a temperature of at least 45.degree. C.
[0034] In another aspect, a method includes detecting a fill event
of a storage tank for storing an AUS; disabling a quality
diagnostic of the AUS after detecting the fill event; and
outgassing the AUS before enabling the quality diagnostic.
[0035] In one embodiment of the method, after outgassing the AUS,
the method includes performing an AUS diagnostic by operating a
quality sensor to determine a urea concentration of the AUS by
ultrasonically determining a fluid density of the AUS. In one
refinement, outgassing the AUS includes at least one operation
selected from the operations consisting of: heating the AUS for at
least 30 minutes, heating the AUS to a temperature rise of at least
30.degree. C., and heating the AUS to a temperature of at least
45.degree. C. In another refinement of the method, heating the AUS
includes opening a heat exchange valve of a heat exchange circuit
to circulate a heat exchange fluid that is heated by operation of
an internal combustion engine to the storage tank. In another
embodiment, detecting the fill event includes determining whether
an AUS level in the storage tank has increased since a last known
fill level detection.
[0036] In another aspect, an apparatus includes an electronic
controller connected to an AUS storage tank level sensor and an AUS
quality sensor associated with an AUS storage tank for providing
AUS to an exhaust system. The controller is further connected to a
heating device and includes a storage tank level determination
module configured to detect a fill event of AUS in the storage
tank, a quality determination module configured to determine a
quality of the AUS in the storage tank and output a quality
condition associated with the quality of the AUS, and an AUS
outgassing module configured to disable output of the quality
condition by the quality determination module upon the detection of
the fill event by the storage tank level determination module. The
AUS outgassing module is further configured to control the heating
device to increase a temperature of the AUS a predetermined amount
before enabling output of the quality condition by the quality
determination module.
[0037] In one embodiment, the heating device includes a heat
exchange circuit that provides a flow of heating fluid to the
storage tank for heating of the AUS. In another embodiment, the
quality determination module is configured to output to a display
an indication of the AUS quality.
[0038] According to another aspect, a system includes an internal
combustion engine including an exhaust system; a dosing system
connected to the exhaust system to provide AUS to the exhaust
system; and a storage tank for storing AUS connected to the dosing
system The storage tank includes a level sensor operable to
indicate a level of AUS in the storage tank, a quality sensor
operable to indicate a quality condition of the AUS in the storage
tank, and a temperature sensor operable to indicate a temperature
of the AUS in the storage tank. The system also includes a heat
exchange system configured to heat the AUS and a controller
connected to the heat exchange system that is operable to control
heating of the AUS in the storage tank. The controller is
configured to suspend an output of the indication of the quality
condition of the AUS and increase a temperature of the AUS a
predetermined amount in response at least in part to an indication
from the level sensor that the level of AUS in the storage tank has
increased.
[0039] In one embodiment, the heat exchange system defines a flow
path that is arranged to circulate a heat exchange fluid to
thermally contact heated heat exchange fluid with the AUS in the
storage tank. The heat exchange system further includes a control
valve in the flow path to control a flow of the heat exchange fluid
in the flow path. In one refinement, the controller is configured
to initiate a circulation period of the heated heat exchange fluid
in the flow path through the storage tank to increase the
temperature of the AUS in the storage tank the predetermined
amount. In a further refinement, the predetermined amount includes
at least one of the AUS being heated to a temperature threshold, an
increase in temperature of the AUS by a predetermined amount, and a
heating the AUS at a predetermined temperature for a length of
time.
[0040] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only certain exemplary embodiments have been
shown and described. Those skilled in the art will appreciate that
many modifications are possible in the example embodiments without
materially departing from this invention. Accordingly, all such
modifications are intended to be included within the scope of this
disclosure as defined in the following claims.
[0041] In reading the claims, it is intended that when words such
as "a," "an," "at least one," or "at least one portion" are used
there is no intention to limit the claim to only one item unless
specifically stated to the contrary in the claim. When the language
"at least a portion" and/or "a portion" is used the item can
include a portion and/or the entire item unless specifically stated
to the contrary.
* * * * *