U.S. patent application number 16/715243 was filed with the patent office on 2020-04-16 for exhaust aftertreatment system diagnostic and conditioning.
This patent application is currently assigned to Cummins IP, Inc.. The applicant listed for this patent is Cummins IP, Inc.. Invention is credited to Stephen J. Charlton, Tony J. Hall, Michael J. McGuire.
Application Number | 20200116068 16/715243 |
Document ID | / |
Family ID | 51863822 |
Filed Date | 2020-04-16 |
United States Patent
Application |
20200116068 |
Kind Code |
A1 |
Hall; Tony J. ; et
al. |
April 16, 2020 |
EXHAUST AFTERTREATMENT SYSTEM DIAGNOSTIC AND CONDITIONING
Abstract
A diagnostic engine calibration module is provided that is
structured to diagnose a vehicle system by causing the vehicle
system to operate outside of one or more calibration parameters.
The diagnostic engine calibration module includes a diesel
particulate filter (DPF) pressure module structured to determine a
pressure differential across a DPF of an engine of the vehicle
system and compare the determined pressure differential against a
plurality of predetermined fault thresholds to diagnose the DPF,
the plurality of predetermined fault thresholds including a
predetermined minimum pressure threshold and a predetermined
maximum pressure threshold.
Inventors: |
Hall; Tony J.; (Bemus Point,
NY) ; Charlton; Stephen J.; (Rancho Sante Fe, CA)
; McGuire; Michael J.; (Columbus, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cummins IP, Inc. |
Columbus |
IN |
US |
|
|
Assignee: |
Cummins IP, Inc.
Columbus
IN
|
Family ID: |
51863822 |
Appl. No.: |
16/715243 |
Filed: |
December 16, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15630279 |
Jun 22, 2017 |
10508582 |
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16715243 |
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14270907 |
May 6, 2014 |
9708960 |
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15630279 |
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61821143 |
May 8, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 2550/02 20130101;
Y02T 10/26 20130101; F02D 41/1446 20130101; F02D 41/146 20130101;
F02D 41/0235 20130101; F01N 3/2066 20130101; F01N 2900/1406
20130101; F01N 2550/04 20130101; F02D 2200/0811 20130101; F01N
9/002 20130101; F02D 41/042 20130101; Y02T 10/12 20130101; Y02T
10/47 20130101; Y02A 50/20 20180101; F02D 41/029 20130101; F02D
41/222 20130101; F02D 2200/0802 20130101; G01M 15/102 20130101;
F02D 41/1441 20130101; F02D 41/22 20130101; Y02A 50/2325 20180101;
Y02T 10/40 20130101; F01N 11/00 20130101; B01D 53/9418 20130101;
F01N 3/029 20130101; F01N 2900/0414 20130101; F02D 2200/0812
20130101; F01N 11/002 20130101; F02D 41/024 20130101; F02D 41/2432
20130101; F01N 2550/00 20130101; F01N 2900/1402 20130101; F01N
2550/05 20130101 |
International
Class: |
F01N 11/00 20060101
F01N011/00; F01N 9/00 20060101 F01N009/00; F01N 3/20 20060101
F01N003/20; F01N 3/029 20060101 F01N003/029; B01D 53/94 20060101
B01D053/94; G01M 15/10 20060101 G01M015/10; F02D 41/24 20060101
F02D041/24; F02D 41/22 20060101 F02D041/22; F02D 41/14 20060101
F02D041/14; F02D 41/02 20060101 F02D041/02 |
Claims
1. An apparatus, comprising: a diagnostic engine calibration module
structured to diagnose a vehicle system by causing the vehicle
system to operate outside of one or more calibration parameters,
wherein the diagnostic engine calibration module includes: a diesel
particulate filter (DPF) pressure module structured to determine a
pressure differential across a DPF of an engine of the vehicle
system and compare the determined pressure differential against a
plurality of predetermined fault thresholds to diagnose the DPF,
the plurality of predetermined fault thresholds including a
predetermined minimum pressure threshold and a predetermined
maximum pressure threshold.
2. The apparatus of claim 1, wherein the diagnostic engine
calibration module is structured to only operate the vehicle system
when the engine is immobilized.
3. The apparatus of claim 1, wherein the diagnostic engine
calibration module is structured to operate the vehicle system when
the engine is turned on.
4. The apparatus of claim 1, wherein the diagnostic engine
calibration module includes a DPF ash restriction module structured
to determine an amount of ash that remains on the diesel
particulate filter and trigger a fault if the amount of ash meets
or exceeds an upper threshold.
5. The apparatus of claim 4, wherein the DPF ash restriction module
is triggered when the determined pressure differential is below the
predetermined minimum pressure threshold.
6. The apparatus of claim 1, wherein the DPF pressure module is
further structured to determine an initial pressure differential
across the diesel particulate filter of the engine of the vehicle
system before the engine is initially turned on and compare the
initial pressure differential against zero.
7. The apparatus of claim 1, wherein the diagnostic engine
calibration module is uploaded to an electronic control unit of a
vehicle when the vehicle is immobilized and removed from the
electronic control unit prior to mobilization of the vehicle.
8. The apparatus of claim 1, wherein the diagnostic engine
calibration module includes a diesel oxidation catalyst (DOC)/DPF
module structured to compare DOC and DPF temperature sensor
readings to each other after the engine has run at an idle speed
for a predetermined amount of time after running the engine at a
relatively higher speed for another predetermined amount of
time.
9. A controller for a vehicle, the controller comprising: a
diagnostic engine calibration module structured to diagnose a
vehicle system by causing the vehicle system to operate outside of
one or more calibration parameters, wherein the diagnostic engine
calibration module includes: a diesel oxidation catalyst (DOC)
performance module structured to activate a hydrocarbon (HC) dosing
event, monitor a NO to NO.sub.2 conversion rate within an
aftertreatment system of the vehicle system as a function of HC
dosing, and compare the NO to NO.sub.2 conversion rate against a
plurality of predetermined standards to diagnose a DOC of the
aftertreatment system.
10. The controller of claim 9, wherein the diagnostic engine
calibration module is structured to only operate the vehicle system
when an engine of the vehicle system is immobilized.
11. The controller of claim 9, wherein the diagnostic engine
calibration module is structured to only operate the vehicle system
when an engine of the vehicle system is turned on.
12. The controller of claim 9, wherein the DOC performance module
is further structured to recondition the DOC of the aftertreatment
system if the NO to NO.sub.2 conversion rate does not fall within
the plurality of predetermined standards by increasing a
temperature of exhaust gas from an engine of the vehicle system and
a NOx value from exhaust gas from the engine by adjusting an
exhaust gas recirculation (EGR) fraction and a timing of the fuel
injectors.
13. The controller of claim 9, wherein the diagnostic engine
calibration module includes a DOC/diesel particulate filter (DPF)
module structured to compare DOC and DPF temperature sensor
readings to each other after an engine of the vehicle system has
run at an idle speed for a predetermined amount of time after
running the engine at a relatively higher speed for another
predetermined amount of time.
14. An internal combustion engine system, comprising: a controller
comprising memory that stores a diagnostic engine calibration
program, the diagnostic engine calibration program structured to
diagnose the internal combustion engine system without user
intervention; wherein the diagnostic engine calibration program
includes a diesel particulate filter (DPF) pressure module
structured to determine a pressure differential across a diesel
particulate filter of an engine of the internal combustion engine
system and compare the determined pressure differential against a
plurality of predetermined fault thresholds, the plurality of
predetermined fault thresholds including a predetermined minimum
pressure threshold and a predetermined maximum pressure threshold,
and wherein the diagnostic engine calibration module is configured
as an intrusive diagnostic process that causes the internal
combustion engine system to operate outside of one or more
calibration parameters.
15. The system of claim 14, wherein the diagnostic engine
calibration program is structured to operate when the engine is
turned on.
16. The system of claim 14, wherein the diagnostic engine
calibration program includes a DPF ash restriction module
structured to determine an amount of ash that remains on the diesel
particulate filter and trigger a fault if the amount of ash meets
an upper threshold.
17. The system of claim 16, wherein the DPF ash restriction module
is utilized by the diagnostic engine calibration program when the
determined pressure differential is below the predetermined minimum
pressure threshold.
18. The system of claim 14, wherein the DPF pressure module is
further structured to determine an initial pressure differential
across the diesel particulate filter of the engine of the vehicle
system before the engine is initially turned on and compare the
initial pressure differential against a threshold.
19. The system of claim 14, wherein the diagnostic engine
calibration program is uploaded to the controller when the engine
is immobilized and removed from the controller prior to
mobilization of the engine.
20. The system of claim 14, wherein the diagnostic engine
calibration module includes a diesel oxidation catalyst (DOC)/DPF
module structured to compare DOC and DPF temperature sensor
readings to each other after the engine has run at an idle speed
for a predetermined amount of time after running the engine at a
relatively higher speed for another predetermined amount of time.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/630,279 entitled "EXHAUST AFTERTREATMENT
SYSTEM DIAGNOSTIC AND CONDITIONING" filed Jun. 22, 2017, which is a
continuation of U.S. patent application Ser. No. 14/270,907
entitled "EXHAUST AFTERTREATMENT SYSTEM DIAGNOSTIC AND
CONDITIONING," filed May 6, 2014, which claims the benefit of and
priority to U.S. Provisional Patent Application No. 61/821,143
entitled "EXHAUST AFTERTREATMENT SYSTEM DIAGNOSTIC AND
CONDITIONING," filed May 8, 2013, all of which are incorporated
herein by reference in their entireties.
BACKGROUND
[0002] Emissions regulations for internal combustion engines have
become more stringent over recent years. Environmental concerns
have motivated the implementation of stricter emission requirements
for internal combustion engines throughout much of the world.
Governmental agencies, such as the Environmental Protection Agency
(EPA) in the United States, carefully monitor the emission quality
of engines and set acceptable emission standards, to which all
engines must comply. Consequently, the use of exhaust
aftertreatment systems on engines to reduce emissions is
increasing.
[0003] Generally, emission requirements vary according to engine
type. Emission tests for compression-ignition (diesel) engines
typically monitor the release of carbon monoxide (CO), unburned
hydrocarbons (UHC), diesel particulate matter (PM) such as ash and
soot, and nitrogen oxides (NOx). Oxidation catalysts, such as
diesel oxidation catalysts (DOC) have been implemented in exhaust
gas aftertreatment systems to oxidize at least some particulate
matter in the exhaust stream, reduce unburned hydrocarbons and CO
in the exhaust to less environmentally harmful compounds, and
oxidize nitric oxide (NO) to form nitrogen dioxide (NO.sub.2),
which is used in the NOx conversion on an selective catalytic
reduction (SCR) catalyst. To remove the particulate matter, a
particulate matter (PM) filter is typically installed downstream
from the oxidation catalyst or in conjunction with the oxidation
catalyst. However, some exhaust aftertreatment systems do not have
a PM filter. With regard to reducing NOx emissions, NOx reduction
catalysts, including SCR systems, are utilized to convert NOx (NO
and NO.sub.2 in some fraction) to N.sub.2 and other compounds.
Further, some systems include an ammonia oxidation (AMOX) catalyst
downstream of the SCR catalyst to convert at least some ammonia
slipping from the SCR catalyst to N.sub.2 and other less harmful
compounds.
[0004] Exhaust aftertreatment system components can be susceptible
to failure and degradation. Because the failure or degradation of
components may have adverse consequences on the performance and
emission-reduction capability of the exhaust aftertreatment system,
the detection and, if possible, correction of failed or degraded
components is desirable. In fact, some regulations require on-board
diagnostic (OBD) monitoring or testing of many of the various
components and performance of an exhaust aftertreatment system.
When equipped on vehicles, most monitoring and testing of
aftertreatment system components and performance are performed
during on-road operation of the vehicle (e.g., while the vehicle is
being driven on the road). Although such monitoring and testing
while the vehicle is in use may be convenient, the efficacy of the
monitoring and testing diagnostic procedures, as well as any
recovery procedures, are limited because the engine cannot be
operated outside of a given on-road calibrated operating range.
Additionally, because on-road operating demands typically have
priority over diagnostic and performance recovery procedures, the
order, timing, and control of such procedures may be less than
ideal.
SUMMARY
[0005] One embodiment relates to an apparatus that includes a
diagnostic engine calibration module. The diagnostic engine
calibration module is structured to include a plurality of
diagnostic processes for operating an internal combustion engine
system of an immobilized vehicle. Each diagnostic process is
structured to bring the internal combustion engine system to one or
more operating points prior to running a subsequent diagnostic
process to enable a diagnosis of a component of the internal
combustion engine system relating to the currently ran diagnostic
process. The diagnostic engine calibration module is further
structured to control the order and timing of each diagnostic
process in the plurality of diagnostic processes.
[0006] Another embodiment relates to internal combustion engine
system, comprising an internal combustion engine system, and a
controller comprising memory designated for storage of an engine
calibration program and a diagnostic engine calibration program,
the engine calibration program structured to operate the internal
combustion engine system while the internal combustion engine
system is mobilized. The diagnostic engine calibration program
includes a plurality of diagnostic processes for operating the
internal combustion engine system while the internal combustion
engine system is immobilized. The diagnostic processes include a
diesel particulate filter (DPF) pressure fault process and a DPF
ash restriction process. Each diagnostic process is structured to
bring the internal combustion engine system to one or more
operating points prior to running a subsequent diagnostic process
to enable a diagnosis of a component of the internal combustion
engine system relating to the currently ran diagnostic process. The
diagnostic engine calibration program is further structured to
control the order and timing of each diagnostic process in the
plurality of diagnostic processes.
[0007] Still another embodiment relates to a method for diagnosing
and conditioning an internal combustion engine system of a vehicle.
The method includes immobilizing the vehicle in a controlled
environment; removing a production engine calibration program from
an electronic control unit of the internal combustion engine
system; uploading a diagnostic engine calibration program to the
electronic control unit; running the diagnostic engine calibration
program while the vehicle is immobilized in the controlled
environment, the diagnostic engine calibration including a
plurality of diagnostic processes for operating an immobilized
vehicle; removing the diagnostic engine calibration program from
the electronic control unit after completion of the plurality of
commands; and uploading the production engine calibration program
to the electronic control unit. Each diagnostic process is
structured to bring the internal combustion engine system to one or
more operating points prior to running a subsequent diagnostic
process to enable a diagnosis of a component of the internal
combustion engine system relating to the currently ran diagnostic
process.
[0008] Yet another embodiment relates to an apparatus comprising a
diagnostic engine calibration module structured to include a
plurality of diagnostic processes for operating an internal
combustion engine system of a vehicle. Each diagnostic process is
structured to bring the internal combustion engine system to one or
more operating conditions prior to running a subsequent diagnostic
process to enable a diagnosis of a component of the internal
combustion engine system relating to the currently ran diagnostic
process. The diagnostic engine calibration module is structured to
activate the plurality of diagnostic processes in the following
order: a DPF pressure sensor fault process; a DPF pressure check
fault process; a DEF deposit regeneration process; a DOC
performance test; a low NOx sensor rationality test; a SCR
performance test before an SCR regeneration event; an SCR
performance test with an SCR regeneration event; a DPF ash
restriction process; a high NOx sensor rationality test; a DOC and
DPF temperature sensor rationality test; and a SCR temperature
sensor rationality test.
[0009] The subject matter of the present application has been
developed in response to the present state of the art, and in
particular, in response to the problems and needs in the exhaust
aftertreatment system diagnostic and recovery art that have not yet
been fully solved by currently available diagnostic and recovery
techniques. Accordingly, the subject matter of the present
application has been developed to provide methods, systems, and
apparatus for diagnosing the condition and recovering the
performance of exhaust aftertreatment system components.
[0010] In certain embodiments, the modules of the apparatus
described herein may each include at least one of logic hardware
and executable code, the executable code being stored on one or
more memory devices. The executable code may be replaced with a
computer processor and computer-readable storage medium that stores
executable code executed by the processor.
[0011] Reference throughout this specification to features,
advantages, or similar language does not imply that all of the
features and advantages that may be realized with the subject
matter of the present disclosure should be or are in any single
embodiment. Rather, language referring to the features and
advantages is understood to mean that a specific feature,
advantage, or characteristic described in connection with an
embodiment is included in at least one embodiment of the present
disclosure. Thus, discussion of the features and advantages, and
similar language, throughout this specification may, but do not
necessarily, refer to the same embodiment.
[0012] The described features, structures, advantages, and/or
characteristics of the subject matter of the present disclosure may
be combined in any suitable manner in one or more embodiments
and/or implementations. In the following description, numerous
specific details are provided to impart a thorough understanding of
embodiments of the subject matter of the present disclosure. One
skilled in the relevant art will recognize that the subject matter
of the present disclosure may be practiced without one or more of
the specific features, details, components, materials, and/or
methods of a particular embodiment or implementation. In other
instances, additional features and advantages may be recognized in
certain embodiments and/or implementations that may not be present
in all embodiments or implementations. Further, in some instances,
well-known structures, materials, or operations are not shown or
described in detail to avoid obscuring aspects of the subject
matter of the present disclosure. The features and advantages of
the subject matter of the present disclosure will become more fully
apparent from the following description and appended claims, or may
be learned by the practice of the subject matter as set forth
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic of an engine system including an
aftertreatment system according to an example embodiment.
[0014] FIG. 2 is a schematic of a controller for an engine system
according to an example embodiment.
[0015] FIG. 3 is a schematic of a diagnostic engine calibration
module for the controller of FIG. 2 according to an example
embodiment.
[0016] FIG. 4 is a method for diagnosing and reconditioning an
engine system according to an example embodiment.
DETAILED DESCRIPTION
[0017] Referring to the figures generally, systems and methods of
troubleshooting an engine system are shown according to various
example embodiments. According to the present disclosure, a
calibration program is structured to be applied to an engine
control module ("ECM"). Upon application, the calibration program,
via the ECM, causes one or more intrusive diagnostic tests. The
diagnostic tests are structured to cause the engine to operate at
various operating parameters. The diagnostic tests allow a
technician to trouble shoot the aftertreatment system efficiently
and quickly. Moreover, the diagnostic tests allow the technician to
quickly diagnose which component(s) of the aftertreatment system
are malfunctioning or about to malfunction. This enables a
relatively faster turnaround for repair sessions for the
aftertreatment system, which may save the customer time and money.
After completion of the diagnostic session, the calibration program
is removed from the ECM, such that the ECM operates according to
the pre-existing engine set points thereafter.
[0018] As used herein, the term "intrusive" (in regard to
performing one or more diagnostic tests) is used to refer to
operating the engine of the vehicle outside of various preset
engine operating points (e.g., there may be a limit on the maximum
engine speed). More specifically, "intrusive diagnostic tests"
refer to overriding various set engine operating points to perform
the tests. For example, many engine operating points are set to be
in compliance with one or more vehicular laws (e.g., emissions). By
overriding one or more of these operating points, the engine may be
forced into non-compliance with one or more vehicular laws. As
described herein, a calibration program is uploaded into the ECM of
the vehicle to cause operation of the intrusive diagnostics tests.
These tests allow for the efficient diagnosis of various components
of the engine system (to determine which one, if any, needs to be
repaired, replaced, or otherwise inspected).
[0019] FIG. 1 depicts one embodiment of an engine system 10. The
main components of the engine system 10 include an internal
combustion engine 20 and an exhaust aftertreatment system 22 in
exhaust gas-receiving communication with the engine 20. The
internal combustion engine 20 can be a compression-ignited internal
combustion engine, such as a diesel-fueled engine, or a
spark-ignited internal combustion engine, such as a gasoline-fueled
engine operated lean. Although not shown, on the air intake side,
the engine system 10 can include an air inlet, inlet piping, a
turbocharger compressor, and an intake manifold. The intake
manifold includes an outlet that is operatively coupled to
compression chambers of the internal combustion engine 20 for
introducing air into the compression chambers.
[0020] Within the internal combustion engine 20, air from the
atmosphere is combined with fuel, and combusted, to power the
engine. The fuel comes from a fuel tank (not shown) through a fuel
delivery system including, in one embodiment, a fuel pump and
common rail to the fuel injectors, which inject fuel into the
combustion chambers of the engine 20. Fuel injection timing can be
controlled by the controller 100 via a fuel injector control
signal.
[0021] Combustion of the fuel and air in the compression chambers
of the engine 20 produces exhaust gas that is operatively vented to
an exhaust manifold (not shown). From the exhaust manifold, a
portion of the exhaust gas may be used to power a turbocharger
turbine. The turbocharger turbine drives the turbocharger
compressor, which may compress at least some of the air entering
the air inlet before directing it to the intake manifold and into
the compression chambers of the engine 20.
[0022] The exhaust aftertreatment system 10 includes the controller
100 (which also can form part of the overall engine system 10), a
diesel particular filter (DPF) 40, a diesel oxidation catalyst
(DOC) 30, a selective catalytic reduction (SCR) system 52 with an
SCR catalyst 50, and an ammonia oxidation (AMOX) catalyst 60. The
SCR system 52 further includes a reductant delivery system that has
a diesel exhaust fluid (DEF) source 54 that supplies DEF to a DEF
doser 56 via a DEF line 58.
[0023] In an exhaust flow direction, as indicated by directional
arrow 29, exhaust gas flows from the engine 20 into inlet piping 24
of the exhaust aftertreatment system 22. From the inlet piping 24,
the exhaust gas flows into the DOC 30 and exits the DOC into a
first section of exhaust piping 28A. From the first section of
exhaust piping 28A, the exhaust gas flows into the DPF 40 and exits
the DPF into a second section of exhaust piping 28B. From the
second section of exhaust piping 28B, the exhaust gas flows into
the SCR catalyst 50 and exits the SCR catalyst into the third
section of exhaust piping 28C. As the exhaust gas flows through the
second section of exhaust piping 28B, it is periodically dosed with
DEF by the DEF doser 56. Accordingly, the second section of exhaust
piping 28B acts as a decomposition chamber or tube to facilitate
the decomposition of the DEF to ammonia. From the third section of
exhaust piping 28C, the exhaust gas flows into the AMOX catalyst 50
and exits the AMOX catalyst into outlet piping 26 before the
exhaust gas is expelled from the system 22. Based on the foregoing,
in the illustrated embodiment, the DOC 30 is position upstream of
the DPF 40 if present and the SCR catalyst 50, and the SCR catalyst
50 is positioned downstream of the DPF 40 when present and upstream
of the AMOX catalyst 60. However, in alternative embodiments, other
arrangements of the components of the exhaust aftertreatment system
22 are also possible.
[0024] The DOC 30 can have any of various flow-through designs
known in the art. Generally, the DOC 30 is configured to oxidize at
least some particulate matter, e.g., the soluble organic fraction
of soot, in the exhaust and reduce unburned hydrocarbons and CO in
the exhaust to less environmentally harmful compounds. For example,
the DOC 30 may sufficiently reduce the hydrocarbon and CO
concentrations in the exhaust to meet the requisite emissions
standards for those components of the exhaust gas. An indirect
consequence of the oxidation capabilities of the DOC 30 is the
ability of the DOC to oxidize NO into NO.sub.2. In this manner, the
level of NO.sub.2 exiting the DOC 30 is equal to the NO.sub.2 in
the exhaust gas generated by the engine 20 plus the NO.sub.2
converted from NO by the DOC. Accordingly, one metric for
indicating the condition of the DOC 30 is the NO.sub.2/NOx ratio of
the exhaust gas exiting the DOC.
[0025] In addition to treating the hydrocarbon and CO
concentrations in the exhaust gas, the DOC 30 can also be used in
the controlled regeneration of the DPF 40, SCR catalyst 50, and
AMOX catalyst 60. This can be accomplished through the injection,
or dosing, of unburned HC into the exhaust gas upstream of the DOC
30. Upon contact with the DOC 30, the unburned HC undergoes an
exothermic oxidation reaction which leads to an increase in the
temperature of the exhaust gas exiting the DOC 30 and subsequently
entering the DPF 40, SCR catalyst 50, and/or the AMOX catalyst 60.
The amount of unburned HC added to the exhaust gas is selected to
achieve the desired temperature increase or target controlled
regeneration temperature.
[0026] The DPF 40 can be any of various flow-through designs known
in the art, and configured to reduce particulate matter
concentrations, e.g., soot and ash, in the exhaust gas to meet
requisite emission standards. The DPF 40 captures particulate
matter and other constituents, and thus needs to be periodically
regenerated to burn off the captures constituents. Additionally,
the DPF 40 may be configured to oxidize NO to form NO.sub.2
independent of the DOC 30.
[0027] As discussed above, the SCR system 52 includes a reductant
delivery system with a reductant (e.g., DEF) source 54, pump (not
shown) and delivery mechanism or doser 56. The reductant source 54
can be a container or tank capable of retaining a reductant, such
as, for example, ammonia (NH.sub.3), DEF (e.g., urea), or diesel
oil. The reductant source 54 is in reductant supplying
communication with the pump, which is configured to pump reductant
from the reductant source to the delivery mechanism 56 via a
reductant delivery line 58. The delivery mechanism 56 is positioned
upstream of the SCR catalyst 50. The delivery mechanism 56 is
selectively controllable to inject reductant directly into the
exhaust gas stream prior to entering the SCR catalyst 50.
[0028] In some embodiments, the reductant can either be ammonia or
DEF, which decomposes to produce ammonia. The ammonia reacts with
NOx in the presence of the SCR catalyst 50 to reduce the NOx to
less harmful emissions, such as N.sub.2 and H.sub.2O. The NOx in
the exhaust gas stream includes NO.sub.2 and NO. Generally, both
NO.sub.2 and NO are reduced to N.sub.2 and H.sub.2O through various
chemical reactions driven by the catalytic elements of the SCR
catalyst in the presence of NH.sub.3. However, as discussed above,
the chemical reduction of NO.sub.2 to N.sub.2 and H.sub.2O
typically is the most efficient chemical reaction. Therefore, in
general, the more NO.sub.2 in the exhaust gas stream compared to
NO, the more efficient the NO.sub.x reduction performed by the SCR
catalyst. Accordingly, the ability of the DOC 30 to convert NO to
NO.sub.2 directly affects the NOx reduction efficiency of the SCR
system 150. Put another way, the NOx reduction efficiency of the
SCR system 52 corresponds at least indirectly to the condition or
performance of the DOC 30. However, primarily, the NOx reduction
efficiency of the SCR system 52 corresponds with the condition or
performance of SCR catalyst 50.
[0029] The SCR catalyst 50 can be any of various catalysts known in
the art. For example, in some implementations, the SCR catalyst 50
is a vanadium-based catalyst, and in other implementations, the SCR
catalyst is a zeolite-based catalyst, such as a Cu-Zeolite or a
Fe-Zeolite catalyst. In one representative embodiment, the
reductant is aqueous urea and the SCR catalyst 50 is a
zeolite-based catalyst.
[0030] The AMOX catalyst 60 can be any of various flow-through
catalysts configured to react with ammonia to produce mainly
nitrogen. Generally, the AMOX catalyst 60 is utilized to remove
ammonia that has slipped through or exited the SCR catalyst 60
without reacting with NO.sub.x in the exhaust. In certain
instances, the aftertreatment system 22 can be operable with or
without an AMOX catalyst. Further, although the AMOX catalyst 60 is
shown as a separate unit from the SCR catalyst 52, in some
implementations, the AMOX catalyst can be integrated with the SCR
catalyst, e.g., the AMOX catalyst and the SCR catalyst can be
located within the same housing. The condition of the AMOX catalyst
60 can be represented by the performance of the AMOX catalyst
(i.e., the ability of the AMOX catalyst to convert ammonia into
mainly nitrogen).
[0031] Various sensors, such as NOx sensors 12, 14 and temperature
sensors 16, 18, may be strategically disposed throughout the
exhaust aftertreatment system 22 and may be in communication with
the controller 100 to monitor operating conditions of the engine
system 10. In one embodiment, the NOx sensor 12 is positioned
upstream of the SCR catalyst 50 and configured to detect the
concentration of NOx in the exhaust gas upstream of the SCR
catalyst (e.g., entering the SCR catalyst). In the present
embodiment, the upstream NOx sensor 12 is positioned upstream of
the DOC 30, but in other embodiments, the upstream NOx sensor 12
can be positioned at any of various locations upstream of the SCR
catalyst 50. The NOx sensor 14 is positioned downstream of the SCR
catalyst 50 and configured to detect the concentration of NOx in
the exhaust gas downstream of the SCR catalyst (e.g., exiting the
SCR catalyst). In the present embodiment, the downstream NOx sensor
14 is positioned downstream of the AMOX catalyst 60 (e.g., at a
tailpipe of the system), but in other embodiments, the downstream
NOx sensor may be positioned upstream of the AMOX catalyst 60.
[0032] The temperature sensors 16 are associated with the DOC 30
and DPF 40, and thus can be defined as DOC/DPF temperature sensors
16. The DOC/DPF temperature sensors are strategically positioned to
detect the temperature of exhaust gas flowing into the DOC 30, out
of the DOC and into the DPF 40, and out of the DPF before being
dosed with DEF by the doser 56. The temperature sensors 18 are
associated with the SCR catalyst 50 and thus can be defined as SCR
temperature sensors 18. The SCR temperature sensors 18 are
strategically positioned to detect the temperature of exhaust gas
flowing into and out of the SCR catalyst 50.
[0033] Although not shown, the engine system 10 and exhaust
aftertreatment system 22 includes many other types of sensors for
detecting other characteristics of the system at various locations
throughout the systems. Also, the systems 10, 22, including the
controller 100, may include various virtual sensors for estimating
various characteristics of the system.
[0034] Although the exhaust aftertreatment system 22 shown includes
one of an DOC 30, DPF 40, SCR catalyst 50, and AMOX catalyst 60
positioned in specific locations relative to each other along the
exhaust flow path, in other embodiments, the exhaust aftertreatment
system may include more than one of any of the various catalysts
positioned in any of various positions relative to each other along
the exhaust flow path as desired. Further, although the DOC 30 and
AMOX catalyst 60 are non-selective catalysts, in some embodiments,
the DOC and AMOX catalyst can be selective catalysts.
[0035] The controller 100 controls the operation of the engine
system 10 and associated sub-systems, such as the internal
combustion engine 20 and the exhaust gas aftertreatment system 22.
The controller 100 is depicted in FIGS. 1 and 2 as a single
physical unit, but can include two or more physically separated
units or components in some embodiments if desired. Generally, the
controller 100 receives multiple inputs 114, processes the inputs,
and transmits multiple commands or outputs. The multiple inputs 114
may include sensed measurements, from the sensors, estimates from
virtual sensors, and various user inputs. The inputs 114 are
processed by the controller 100 using various algorithms, stored
data, and other inputs to update the stored data and/or generate
output values. The generated output values and/or commands are
transmitted to other components of the controller and/or to one or
more elements of the engine system 10 to control the system to
achieve desired results.
[0036] Generally, the controller 100 includes various modules for
controlling the operation of the engine system 10. For example, the
controller 100 includes memory reserved for an engine calibration
module 110 containing calibrated instructions for operation of the
engine system 10. As is known in the art, the controller 100 and
its various modular components may comprise processor, memory, and
interface modules that may be fabricated of semiconductor gates on
one or more semiconductor substrates. Each semiconductor substrate
may be packaged in one or more semiconductor devices mounted on
circuit cards. Connections between the modules may be through
semiconductor metal layers, substrate-to-substrate wiring, or
circuit card traces or wires connecting the semiconductor
devices.
[0037] Referring to FIG. 2, the controller 100, which can be the
electronic control module (ECM) or electronic control unit (ECU) of
a vehicle, includes memory reserved for an engine calibration
module 110 or program with instructions for operating the engine
system 10. When executed, the engine calibration module 110
generates engine control commands 112 for actuating the various
components of the engine system 10 necessary for operation of the
engine system according to the engine calibration set by the
module. The engine calibration module 110 also receives inputs 114
from various sources, such as one or more of the plurality of
sensors of the engine system 10, and user input, such as actuation
of an accelerator pedal or activation of an auxiliary system, and
provides diagnostic outputs 116.
[0038] As used herein, the term "calibration module" refers to
stored operation parameters that are mostly permanent. They are
mostly permanent because end-users are usually prevented from
adjusting the operation parameters stored in the calibration module
(i.e., the calibration parameters). For reference, in comparison,
an adjustable operation parameter may include the cruise set-speed,
which is adjustable by an end user. In regard back to the
calibration module parameters, the original equipment manufacturer
("OEM") can usually adjust them. Accordingly, these parameters are
usually engineering-type parameters and/or closely-held OEM
parameters (e.g., a maximum power output of the engine). According
to the present disclosure, the diagnostic engine calibration module
130 includes commands to cause the diagnostic tests described
herein to be intrusive, such that one or more engineering-type
and/or closely-held OEM parameters are overridden during operating
of the commands.
[0039] As such, the engine calibration module 110 may include
instructions that cause the otherwise permanent operation
parameters (i.e., the engineering-type and/or closely-held OEM set
parameters) to be overridden. Thus, as mentioned above, in one
embodiment, the engine calibration module 110 is structured as an
intrusive diagnostics module (as opposed to a non-intrusive
diagnostics module, where the commands for operating the engine
system do not cause the engine to operate outside of the mostly
permanent operation set points of the engine system). By overriding
these set points, the engine may operate outside of various
vehicular laws and/or on-road standards (e.g., cause an
unacceptable amount of emissions). As an example, take a usually
permanent parameter: the commands of the vehicle operator (e.g.,
depression of the accelerator pedal) are always obeyed by the
controller (e.g., ECM). However, the engine calibration module 110
may override this permanent parameter to perform its stored
operations and disregard the commands from the operator (hence,
intrusive). This type of control may be illegal if used on a road
(i.e., outside the service bay) due to the operations of the module
110 not being able to react to other drivers and/or obey posted
laws.
[0040] Referring now back to FIG. 2, prior to use by an end-user, a
production engine calibration module 120 is uploaded to the
controller 100 and saved in the memory reserved for the engine
calibration module 110. In essence, after being uploaded, the
production engine calibration module 120 becomes the engine
calibration module 110 for operation of the engine system 10. The
production engine calibration module 120 includes instructions that
are specifically calibrated for operating the engine system 10
under normal on-road operation of the vehicle housing the engine
system. Accordingly, the production engine calibration module 120
calibrates the engine system 10 to meet engine production standards
or regulations set by regulatory agencies. In other words, the
operating parameters or conditions of the engine system 10 are
purposefully limited in order to comply with various standards
associated with normal on-road use of the vehicle, such as
emissions standards, fuel consumption standards, temperature
standards, and on-board diagnostic ("OBD") standards. Therefore,
although the production engine calibration module 120 may include
instructions for conducting diagnostic testing of the engine system
10, the operating parameters of the diagnostic tests are
constrained due to the need for compliance with the regulated
normal on-road standards. Similarly, although the production engine
calibration module 120 may include instructions for conducting
recondition or recovery processes (e.g., regeneration events) for
reconditioning or recovering the performance of various components
of the engine system 10, the efficacy of the processes may be
limited due to the constraints imposed by the necessary compliance
with the regulated normal on-road standards. As mentioned above,
these are the mostly permanent operating parameters that are set by
the calibration module 120.
[0041] After delivery to an end-user, and likely after some use of
the vehicle by the end-user, the vehicle may be immobilized or
rendered stationary (e.g., maintained in park or out-of-gear) for a
variety of reasons. For example, the vehicle may be brought into a
service bay for scheduled or non-scheduled maintenance (e.g.,
repairs). While in the service bay, the vehicle remains
immobilized, while the engine system 10 of the vehicle remains
operational. In this manner, and because the vehicle is maintained
in the controlled environment of the service bay (i.e., the vehicle
is not being operated on the road), the operation of the vehicle is
not constrained by the regulated normal on-road standards.
[0042] While in the service bay, whether before or after the
maintenance is performed, the production engine calibration module
120 is removed or deleted from the controller 100, and is replaced
by the diagnostic engine calibration module 130 as the engine
calibration module 110 of the controller, which allows for the
intrusive diagnostic tests (described herein) to be performed.
Although not shown, a diagnostic tool can be coupled in data
transmitting communication with the controller 100 via a data
communication link or bus. The diagnostic tool can be configured to
delete or command deletion of the production engine calibration
module 120 from the memory reserved for the engine calibration
module 110. Alternatively, the diagnostic tool can remove a copy of
the production engine calibration module 120, as indicated by
bi-directional arrows in FIG. 2, and store the production engine
calibration module 120 on the tool.
[0043] After the production engine calibration module 120 is
deleted or removed by the tool, the tool can be used to upload the
diagnostic engine calibration module 130 into the memory reserved
for the engine calibration module 110. In this manner, the original
production engine calibration module 120 is replaced by the
diagnostic engine calibration module 130. The diagnostic engine
calibration module 130 includes instructions that are specifically
calibrated for operating the engine system 10 under a dedicated
diagnostic operation of the vehicle housing the engine system. The
instructions include one or more diagnostic processes that are
structured to bring the internal combustion engine system to one or
more operating conditions prior to performance of a subsequent
diagnostic process to enable diagnosis of a component in the
internal combustion engine system relating to the currently ran
diagnostic process. As mentioned above, because operation of the
vehicle is free of regulated constraints in the controlled
environment of the service bay, the dedicated diagnostic operation
of the vehicle and engine system 10 utilizes operating conditions
not otherwise allowed during normal on-road use of the vehicle for
achieving more accurate and efficient diagnostic and reconditioning
results. When the diagnostic and reconditioning processes of the
diagnostic engine calibration module 130 are complete, the
diagnostic engine calibration module 130 is removed from the
controller 100 (e.g., either deleted or a copy is removed, as
indicated by bi-directional arrows in FIG. 2) and replaced by the
production engine calibration module 120 via operation of the tool.
After the production engine calibration module 120 is uploaded back
into the memory reserved for the engine calibration module 110, the
vehicle and engine system 10 is equipped to return to normal
on-road operating conditions (i.e., engine system operation within
the previously existing mostly permanent operation parameters of
the production engine calibration module 120).
[0044] Referring to FIG. 3, the diagnostic engine calibration
module 130 includes a plurality of modules each configured with
instructions to automatically execute one or more diagnostic or
reconditioning processes without user input. Additionally, the
diagnostic engine calibration module 130 includes logic to
automatically and sequentially control the order and timing (i.e.,
start and end) of the diagnostic and reconditioning processes
executed by the modules. In other words, once the diagnostic engine
calibration module 130 is installed and initiated, the diagnostic
and reconditioning processes run automatically without user
intervention (e.g., a driver is not controlling operation of the
vehicle). The diagnostic engine calibration module 130 generates
the engine control commands 112 that actuate the components of the
engine system 10. In one embodiment, the diagnostic engine
calibration module 130 is an intrusive diagnostics tool, such that
the commands cause an override of otherwise-set engine operating
parameters (e.g., maximum power output). Accordingly, one or more
of the tests described herein (in regard to the modules) may also
be intrusive. The diagnostic engine calibration module 130 may also
provide diagnostic outputs 116 that may include indications of the
conditions or health of the engine system 10, and its various
components, and a prediction of the remaining life of such
components.
[0045] The modules (and accompanying diagnostic processes) of the
diagnostic engine calibration module 130 may now be described.
According to one example, the diagnostic processes are arranged in
the following order of operation: 1) DPF pressure sensor fault
process while the ECM is on and the engine is off; 2) DPF pressure
check fault process while the engine and ECM are on; 3) a DEF
deposit regeneration process; 4) DOC performance process; 5) a low
NOx sensor rationality test; 6) a SCR performance test before an
SCR regeneration; 7) an SCR performance test after an SCR
regeneration event (e.g., desulfurization (DeSOx)); 8) if an SCR
fault is received, perform a doser diagnostic test; 9) DPF ash
restriction test; 10) a high NOx sensor rationality test; and 11)
compare DOC/DPF thermistors to one another, compare SCR thermistors
to one another, and perform another NOx sensor rationality
test.
[0046] This example order of operations allows the diagnosis
(malfunctioning, potentially malfunctioning, and/or correctly
function) of one or more components in the internal combustion
engine system (including the exhaust aftertreatment system). The
example order of operations may be briefly explained as
follows.
[0047] The DPF pressure check fault process is performed when the
engine is off (but the ECM is on) and then when the engine is on
(processes 1-2). When the engine is off, no air should be moving
through the engine such that the pressure sensor reading
(differential across the DPF) is near zero. When the engine is on,
the sensor (or sensors) should measure a substantially greater
pressure difference across the DPF. This may be preset to determine
whether the DPF is functioning correctly. In one embodiment, when
the engine is turned on, the engine will accelerate to
approximately 1800 revolutions-per-minute. A decomposition reactor
(converts diesel exhaust fluid into ammonia) is allowed to burn
diesel exhaust fluid deposits (i.e., DEF deposit regeneration
process, process 3). During the burn, the DOC performance may be
monitored (process 4). Because of the high engine speed, a higher
flow rate is going through the exhaust aftertreatment system, which
makes determining potential issues with the DOC easier. In one
embodiment, the fan is locked during this process and a fault code
is set to trigger if the thermostat is leaking. Process 3 enables
the diagnosis of the DOC. In some embodiments, as described below,
a DOC recondition process is also performed (which would occur
here, before process 5). At process 5, a low NOx sensor test is
performed; usually, this test is performed at 100 ppm NOx (low NOx
module 208). At processes 6 and 7, an SCR performance test may be
performed before and after an SCR regeneration event (e.g., DeSOx).
The performance test may be run at approximately 350 g/s exhaust
flow and 350.degree. C. exhaust temperatures. These processes may
enable diagnosis of the SCR component. At process 8, if an SCR
fault is received (i.e., the SCR is not performing according to
various preset parameters, possibly embodied in one or more fault
codes), a doser diagnostic test may be performed. The doser
diagnostic test is a test to check the flow rate of the doser
(i.e., of the reductant through the doser/injector). Thus, one or
more flow sensors may be used with the doser 56 that monitor the
flow rate of a reductant through the doser. Because the fuel
doser/injector can plug up with carbon, the doser diagnostic test
is performed to ensure a proper flow rate through the
doser/injector. The doser diagnostic test may also include
measuring the change in pressure across a fixed orifice size of the
injector. If the change in pressure is above (in some embodiments,
below) a predetermined threshold, this may indicate that the
doser/injector is plugged or clogged with carbon and needs to be
replaced or serviced. At process 9, a DPF ash restriction test may
be performed. A fault code may be triggered if too much ash is
detected. Accordingly, the DPF is being diagnosed at process 9.
After this test, the engine may be run at 16000
revolutions-per-minute (a relatively high speed for a
compression-ignition engine (diesel) that equates to a relatively
higher exhaust flow rate). At process 10, a high NOx sensor test is
performed (e.g., 1000 ppm NOx). After a predetermined amount of
time (e.g., five minutes) at the preset engine speed (e.g., 16000
revolutions-per-minute), the engine may HC doser purge. After this,
the engine may idle for another amount of predetermined amount of
time (e.g., five minutes). Upon completion, at process 11, the
DOC/DPF thermistors are compared to one another, the SCR
thermistors to one another, and (in some embodiments) a third NOx
sensor rationality test is performed. In one example configuration,
a fault code is triggered if the DOC/DPF thermistors are outside of
+/-25.degree. C. of each other. In another example configuration, a
fault code is triggered if the SCR thermistors are outside of
+/-25.degree. C. of each other. After these two checks, the engine
may return to idle. At idle, the NOx sensors may be left on for a
little while longer (adjustable). In one example, a service
technician may datalog the NOx sensor reading after removing the
NOx sensor from the system and letting it hang out in the open.
[0048] As can be seen, this order of operations allows the
diagnosis of one or more components in the exhaust after treatment
system. This order may be rearranged in other embodiments. The
above is a brief overview of the diagnostic processes of the
diagnostic engine calibration module 130. The details of these
processes may be more fully described in regard to the sub-modules
of the diagnostic engine calibration module 130.
[0049] The DPF pressure module 200 is structured to perform a DPF
pressure check fault process. In this process, the module 200 is
configured to set the fault thresholds for the pressure
differential across the DPF 40 and the DPF outlet pressure. Because
the diagnostic and reconditioning processes executed by the modules
of the diagnostic engine calibration module 130 are performed on an
immobilized vehicle in a controlled or contained environment, the
fault thresholds for the DPF pressure differential and DPF outlet
pressure are tighter or less conservative (e.g., threshold values
are within a smaller range) than with diagnostic processes
associated with normal on-road operation of the vehicle. The DPF
pressure module 200 sets the DPF pressure differential and DPF
outlet pressure fault thresholds upon activation of the diagnostic
engine calibration module 130, which may occur upon start-up of the
engine. Thus, the technician may monitor the pressure difference
across the DPF 40 while the engine is on and the ECM is on. If the
pressure differential is above a predetermined maximum amount, this
may indicate that the DPF is not removing enough particles (i.e.,
too high of flow rate). If the pressure differential is below a
predetermined minimum amount, this may indicate that the filter is
full of particles and the exhaust flow is restricted (i.e., the
filter may need to be replaced or cleaned). In this event, a DPF
ash restriction test may be utilized (described herein).
[0050] In one example, the DPF pressure module 200 is structured to
perform a DPF pressure sensor fault process. This process includes
activating the ECM while the internal combustion engine system
remains off In these operating conditions, the internal combustion
engine is not moving air through the system (i.e., the DPF).
Accordingly, the pressure differential across the DPF should be
near zero. This test may indicate the functioning of the pressure
sensor (in some embodiments, pressure sensors) for the DPF. If the
technician notices a pressure differential not in align with this
expectation (may be based on a predetermined percentage difference
from zero that is acceptable), the technician may be alerted to a
possible malfunction of the DPF and would be compelled to examine
the DPF further. In one embodiment, the DPF pressure sensor fault
process is structured to be performed prior to the DPF pressure
check fault process.
[0051] The DEF deposit module 202 is configured to execute a
regeneration event of the exhaust aftertreatment system 22 to
remove DEF deposits, as well as soot and sulfur deposits, which may
have formed within the system (process 3). Such a DEF regeneration
event promotes a clean and relatively DEF deposit free environment
to conduct other diagnostic and reconditioning processes. In one
implementation, the regeneration event executed by the DEF deposit
module 202 includes maintaining the engine speed of the engine 20
at a relatively low desired engine speed (e.g., about 900 RPM),
increasing the temperature of the exhaust gas flowing through the
system 22 to a desired temperature (e.g., about 525-650.degree.
C.), and disabling DEF dosing all for a predetermined amount of
time. The particular conditions of the DEF regeneration event
executed by the DEF deposit module 202 are not conducive to, and
may not be allowable during, normal on-road operation of the
vehicle. This is based on the intrusive nature of the test. For
example, during normal on-road operation of the vehicle, exhaust
gas temperatures reaching about 525-650.degree. C. and disabling
DEF dosing may prevent the engine system 10 from meeting emissions
standards. However, because meeting emissions standards is not a
concern in the immobilized, controlled environment, the particular
conditions of the DEF regeneration event can be tuned to more
effectively remove DEF and other deposits within the system
compared to normal on-road regeneration events. As mentioned above,
in one embodiment, this regeneration event occurs after the SCR
activity check.
[0052] The DOC performance module 204 is configured to monitor and
evaluate the performance of the DOC 30, and recondition the DOC if
necessary. The operating conditions of the DOC performance test and
recondition diagnostic executed by the DOC performance module 204
are also intrusive tests, which may not be acceptable during normal
on-road operating conditions. Relatively high temperatures and high
NOx may act to recondition the DOC. The high NOx and high
temperatures may be accomplished via adjustment to the EGR fraction
and/or the start of injection (e.g., injection timing). This test
utilizes the high temperature and high flow to clean the soot,
fuel, and/or Sulfur from the DOC. The DOC performance module 204
may also enable monitoring of the health of the DOC. In one
embodiment, the DOC performance module 204 is structured to turn on
HC dosing. This inhibits the NO.sub.2 reaction in the DOC. From
this and the NOx conversion rate, differentiation is possible
between the DOC' s health to NO.sub.2 conversion versus the
hydrocarbon conversion rate. Accordingly, the oxidation rate of NO
to NO.sub.2 may be monitored as a function of HC dosing to
determine whether the conversion rate is within predetermined
acceptable standards.
[0053] The NOx sensor module 206 includes several sub-modules each
associated with a separate diagnostic test associated with the NOx
sensors 12, 14 of the engine system 10. Following the DOC
performance and recondition diagnostic of the DOC performance
module 204, the low NOx module 208 of the NOx sensor module 206 is
configured to perform a rationality check of the NOx sensors 12, 14
at a relatively low concentration of engine out NOx (e.g., between
about 75 ppm and about 100 ppm, where "ppm" stands for
parts-per-million). Moving the start of injection or the amount of
EGR fract can achieve this. Accordingly, the NOx sensor error may
be represented as a function of NOx ppm. The low NOx rationality
check includes disabling DEF dosing, determining the difference
between the NOx concentrations detected by the SCR upstream and
downstream NOx sensors 12, 14, setting fault thresholds for the NOx
within a relatively tight range, and comparing the NOx
concentration difference with the fault thresholds. Such a low NOx
rationality check cannot be performed during normal on-road
operation of the vehicle as disabling DEF dosing may prevent the
engine system 10 from meeting emissions standards required during
normal on-road operation.
[0054] The SCR regeneration module 214 is configured to thermally
and chemically regenerate the SCR catalyst 50 to remove sulfur
deposits (DeSOx) from the SCR catalyst. In one implementation, the
SCR regeneration event commanded by the SCR regeneration module 214
includes elevating or maintaining the exhaust gas temperature at an
elevated level and reducing or maintaining the engine speed at a
reduced level for a desired period of time.
[0055] After the SCR catalyst 50 has been regenerated to remove
sulfur deposits, the SCR performance module 216 conducts a
performance test of the regenerated SCR catalyst 50. In one
implementation, the SCR performance test includes increasing the
engine speed to a desired higher engine speed (e.g., 1,800 RPM) and
maximizing the exhaust flow rate by closing EGR valves and
manipulating the characteristics of a turbocharger. More
specifically, the SCR performance test includes allowing the
turbocharger to pump all the air by closing the EGR valve and
pinching down the variable geometry turbocharger. The fueling
injectors are manipulated in such a way that helps build boost and
create heat for the exhaust system. In one example, once the DOC' s
hardware limit of 250.degree. C. of exhaust gas temps is surpassed
(intrusive nature of the test), the fuel doser is enabled to dose
fuel into the exhaust. Once this happens, almost any exhaust
temperature may be targeted. Generally, the exhaust temperature is
chosen to be between 400 and 650.degree. C., depending on what test
is being performed. Some tests may not use the fuel doser, to keep
exhaust temps low. With all these different temperatures and flows
available, the SCR system heath may be mapped to compare to OBD/EPA
regulations to estimate the percent life remaining or if a part
should be replaced. Within this test, the most likely cause of the
performance shift, for example if the DOC NO.sub.2 conversion is
low or the SCR is degraded, or if simply the AMOx is degraded may
be identified to make the best repair possible. Essentially, the
SCR performance test monitors the NOx conversion efficiency of the
SCR catalyst 50 by comparing the NOx concentration readings from
the upstream and downstream NOx sensors 12, 14. Additionally, the
NOx conversion efficiency of the SCR catalyst 50 is tested at
various DEF dosing rates (e.g., 1.0, 2.0, 3.0 ammonia-to-NOx
ratios). Preferably, the SCR performance test is conducted
automatically by the SCR performance module 216, but in some
instances, the SCR performance test can be conducted manually.
[0056] In another example embodiment, at stand-alone emissions
measurement chart may be utilized with this test. Accordingly, this
test would not utilize an engine sensor. Rather, some other
stand-alone sensor for NOx, O.sub.2, CO, exhaust flow, and the like
would be utilized with the SCR performance test.
[0057] The SCR performance module 216 may also trigger an SCR fault
should the performance of the SCR catalyst 50 drop below a minimum
NOx conversion efficiency. If the SCR fault is triggered, the SCR
performance module 216 may include additional modules that conduct
a DEF testing to determine if the DEF delivery system 52 is
malfunctioning and/or the concentration of DEF is low, which may
indicate the DEF is diluted. In regard to the concentration of DEF
being low, there may be three main causes: 1) A piece of hardware
could be bad, such as the SCR, DOC or NOx sensor; 2) The DEF may
not be at the proper concentration, in which a manual test can be
conducted (e.g., a refractometer may be used); or 3) The DEF may
not be pumping into the system, which means there may be a kink, a
suction side leak pumping air instead of DEF, or an external leak.
In one embodiment, items 2 and 3 must be checked out before a piece
of hardware may be said to have failed. Additionally, if an SCR
fault is triggered, a doser diagnostic test may also be performed.
As mentioned above (process 8), the doser diagnostic test is used
to check the flow rate through the doser. If the flow rate is
insufficient (i.e., below a predetermined threshold), the doser may
be malfunctioning and the correct exhaust temperatures may not be
obtained. Accordingly, because the exhaust temperatures may not be
achieved and insufficient reductant is being supplied, the NOx
emissions may not be reduced to a desired level.
[0058] The DPF ash restriction module 218 is configured to conduct
an ash restriction test of the DPF 40. During the regeneration
events conducted by the DEF deposit module 202 and SCR regeneration
module 214, the soot on the DPF 40 is removed. However, the
regeneration events may not remove some species of ash from the DPF
40, such that ash may remain caked on the surface of the DPF
following the regeneration events. Accordingly, the DPF ash
restriction module 218 conducts the ash restriction test to
determine the amount of ash that remains on the DPF 40 and triggers
a fault if the amount of ash meets an upper threshold. In one
embodiment, the DPF ash restriction process includes performing a
pressure differential check across the DPF at a relatively high
exhaust flow rate after a regeneration event of the DPF. This
ensures, or substantially ensures, that the soot is gone in the
DPF.
[0059] After the DPF ash restriction test is completed, the high
NOx module 210 of the NOx sensor module 206 is configured to
perform another rationality check of the NOx sensors 12, 14, but at
a relatively high concentration of engine out NOx (e.g., about 650
ppm) and higher engine speed (e.g., 1,200 RPM). Like the low NOx
rationality check, this high NOx rationality check includes
disabling DEF dosing, determining the difference between the NOx
concentrations detected by the SCR upstream and downstream NOx
sensors 12, 14, setting fault thresholds for the NOx within a
relatively tight range, and comparing the NOx concentration
difference with the fault thresholds. Similar to the low NOx
rationality check, this high NOx rationality check cannot be
performed during normal on-road operation of the vehicle as
disabling DEF dosing may prevent the engine system 10 from meeting
emissions standards required during normal on-road operation.
[0060] The thermostat failure module 220 of the diagnostic engine
calibration module 130 is configured to check the status of a
thermostat of the engine system 10. The thermostat status check
includes maintaining the engine system 10 in a steady state, such
that the cooling system (not shown) of the engine system also is
held in a steady state. With the cooling system in a steady state,
the thermostat can be accurately checked for leakage, and a fault
can be triggered should leakage be detected. Such a steady-state
thermostat check can be difficult, if not nearly impossible, to
conduct under normal on-road operating conditions because of the
difficulty of an engine system operating under normal on-road
conditions to reach a steady-state sufficiently long enough to
accurately detect leakage of the thermostat.
[0061] The diagnostic engine calibration module 130 further
includes a thermistor module 222 with a DOC/DPF module 224 and an
SCR module 226. The DOC/DPF module 224 is configured to test the
rationality of the DOC/DPF temperature sensors 16 and the SCR
module 226 is configured to test the rationality of the SCR
temperature sensors 18 (e.g., the DOC/DPF and SCR thermistors of
process 11 described above). In one implementation, the DOC/DPF
module 224 tests the rationality of the DOC/DPF temperature sensors
16 by maintaining the engine speed at a relatively higher speed
(e.g., approximately 1,200 RPM to 1,600 RPM), maintaining the
exhaust gas temperature at a moderate temperature (e.g.,
200.degree. C.), and maintaining the operations of the engine
system 10 in a steady state. Under these conditions, the
temperature readings of the DOC/DPF temperature sensors 16 are
compared and a fault is triggered if a difference between the
temperature readings meets an upper threshold. Similarly, in one
implementation, the SCR module 226 tests the rationality of the SCR
temperature sensors 18 by maintaining the engine speed at a
relatively higher speed (e.g., approximately 1,200 to 1,6000 RPM),
maintaining the exhaust gas temperature at a moderate temperature
(e.g., 200.degree. C.), and maintaining the operations of the
engine system 10 in a steady state. Under these conditions, the
temperature readings of the SCR temperature sensors 18 are compared
and a fault is triggered if a difference between the temperature
readings meets an upper threshold.
[0062] In one example, regarding the DOC/DPF module 224 and the SCR
module 226, the SCR and DOC/DPF temperature sensors are read after
the engine has been returned to an idle speed for a predetermined
amount of time (e.g., five minutes). In other words, in this
example, the rationality of the sensors are checked by running the
engine at a relatively higher speed, letting the engine idle for a
predetermined amount of time, and then taking one or more readings
from the temperature sensors. The DOC/DPF temperature sensors
readings are compared to each other and the SCR temperature sensor
readings are compared to each other. If there is a difference
between +/-25.degree. C. in the readings, a fault may be triggered.
In which case, one or more of the temperatures sensors may need to
be serviced (repaired, replaced, checked again, etc.). Upon
completion of these tests, the engine may return to an idle speed.
At this point, (process 11 above) an additional NOx sensor
rationality test may be performed.
[0063] The ex situ module 212 of the NOx sensor module 206 is
configured to take and analyze readings taken from a NOx sensor
(e.g., one of NOx sensors 12, 14) removed from exhaust detecting
communication with the exhaust aftertreatment system 22, but
remaining in an operable condition to detect NOx in the air outside
of the exhaust aftertreatment system. Because air has at most
negligible amounts NOx, any detection of NOx in the air by the
removed NOx indicates a faulty NOx sensor. In alternative
embodiments, the ex situ module 212 may be configured to facilitate
the use of an external NOx sensing system that is independent from
the NOx sensors 12, 14 to aid in the detection of the rationality
of any one or more of the NOx sensors.
[0064] Finally, the diagnostic engine calibration module 130
includes an output module 228 configured to receive the results of
the diagnostic and reconditioning tests and processes executed by
the modules, analyze the results, and issue diagnostic outputs 116
representative of the results. In one implementation, the
diagnostic outputs 116 includes an indication of the remaining life
of the components of the engine system, or the general health of
the components. Additionally, the diagnostic outputs 116 may
include indications of any failed or faulty components of the
system that may require reconditioning or replacement.
[0065] Referring to FIG. 4, a method 300 for diagnosing and
reconditioning an engine system is shown. In certain
implementations, the steps of the method 300 may be executed by the
modules of the controller 100 described above. The method 300
begins by immobilizing the vehicle in which an engine system is
housed at 310. Immobilizing the vehicle may include parking the
vehicle in a service bay or other contained environment. The method
300 then includes deleting the production engine calibration
program from the ECU or ECM of the vehicle at 320. The production
engine calibration program may be the original engine calibration
program stored on the ECU during the initial production of the
vehicle. After deleting the production engine calibration program,
the method 300 includes uploading a diagnostic engine calibration
program to the ECU at 330 to effectively replace the deleted
production engine calibration program. In this manner, the engine
system is effectively recalibrated from a normal on-road operating
mode conducive to operation of the vehicle on the road to an
abnormal diagnostic stationary operating mode not conducive to
operation of the vehicle on the road.
[0066] Following uploading of the diagnostic engine calibration
program to the EDU, the method 300 runs the diagnostic engine
calibration program at 340. In one implementation, the initiation
of the diagnostic engine calibration program is triggered by user
input, such as by holding the acceleration pedal down for a
predetermined amount of time (e.g., 10 seconds) or other means of
user input. Running the diagnostic engine calibration program at
340 include automatically and sequentially conducting the various
tests, checks, and reconditioning processes of the modules of a
diagnostic engine calibration module. The tests, checks, and
reconditioning processes are conducted in a particular order, one
after the other, until all desired tests, checks, and
reconditioning processes are completed. In some embodiments,
running the entire diagnostic engine calibration program takes
about an hour. Accordingly, a vehicle can be diagnosed and
reconditioned during a routine or non-routine maintenance
appointment without adding significant down or wait time. According
to one implementation, the diagnostic engine calibration program
includes sequentially executing the following processes in order:
setting of DPF pressure fault thresholds, DEF deposit regeneration,
DOC performance test, low NOx sensor rationality test, SCR catalyst
regeneration, SCR catalyst performance test, DPF ash restriction
test, high NOx sensor rationality test, thermostat failure check,
DOC/DPF temperature sensor rationality test, SCR temperature sensor
rationality test, and manual NOx sensor rationality test if
desired. Of course, other diagnostic and reconditioning processes
can be performed in place of or in addition to those above.
[0067] After running the diagnostic engine calibration program at
340, the method 300 includes generating an exhaust aftertreatment
system status at 350, which can include various outputs of the
tests, estimates of the health of the components of the system,
and/or predictions of the remaining life of the components of the
system. After generating the exhaust aftertreatment system status
at 350, the method 300 deletes or removes the engine calibration
program from the ECU at 360 and uploads the production engine
calibration program back to the ECU. In essence, the production
engine calibration program replaces the diagnostic engine
calibration program such that the engine system is effectively
recalibrated from the abnormal diagnostic stationary operating mode
back to the normal on-road operating mode. Then, the method 300
includes mobilizing the vehicle at 380, which can include driving
the vehicle from the contained environment or service bay back onto
the road.
[0068] The schematic flow chart diagrams and method schematic
diagrams described above are generally set forth as logical flow
chart diagrams. As such, the depicted order and labeled steps are
indicative of representative embodiments. Other steps, orderings
and methods may be conceived that are equivalent in function,
logic, or effect to one or more steps, or portions thereof, of the
methods illustrated in the schematic diagrams.
[0069] Additionally, the format and symbols employed are provided
to explain the logical steps of the schematic diagrams and are
understood not to limit the scope of the methods illustrated by the
diagrams. Although various arrow types and line types may be
employed in the schematic diagrams, they are understood not to
limit the scope of the corresponding methods. Indeed, some arrows
or other connectors may be used to indicate only the logical flow
of a method. For instance, an arrow may indicate a waiting or
monitoring period of unspecified duration between enumerated steps
of a depicted method. Additionally, the order in which a particular
method occurs may or may not strictly adhere to the order of the
corresponding steps shown. It will also be noted that each block of
the block diagrams and/or flowchart diagrams, and combinations of
blocks in the block diagrams and/or flowchart diagrams, can be
implemented by special purpose hardware-based systems that perform
the specified functions or acts, or combinations of special purpose
hardware and program code.
[0070] Many of the functional units described in this specification
have been labeled as modules, in order to more particularly
emphasize their implementation independence. For example, a module
may be implemented as a hardware circuit comprising custom VLSI
circuits or gate arrays, off-the-shelf semiconductors such as logic
chips, transistors, or other discrete components. A module may also
be implemented in programmable hardware devices such as field
programmable gate arrays, programmable array logic, programmable
logic devices or the like.
[0071] Modules may also be implemented in machine-readable medium
for execution by various types of processors. An identified module
of executable code may, for instance, comprise one or more physical
or logical blocks of computer instructions, which may, for
instance, be organized as an object, procedure, or function.
Nevertheless, the executables of an identified module need not be
physically located together, but may comprise disparate
instructions stored in different locations which, when joined
logically together, comprise the module and achieve the stated
purpose for the module.
[0072] Indeed, a module of computer readable program code may be a
single instruction, or many instructions, and may even be
distributed over several different code segments, among different
programs, and across several memory devices. Similarly, operational
data may be identified and illustrated herein within modules, and
may be embodied in any suitable form and organized within any
suitable type of data structure. The operational data may be
collected as a single data set, or may be distributed over
different locations including over different storage devices, and
may exist, at least partially, merely as electronic signals on a
system or network. Where a module or portions of a module are
implemented in machine-readable medium (or computer-readable
medium), the computer readable program code may be stored and/or
propagated on in one or more computer readable medium(s).
[0073] The computer readable medium may be a tangible computer
readable storage medium storing the computer readable program code.
The computer readable storage medium may be, for example, but not
limited to, an electronic, magnetic, optical, electromagnetic,
infrared, holographic, micromechanical, or semiconductor system,
apparatus, or device, or any suitable combination of the
foregoing.
[0074] More specific examples of the computer readable medium may
include but are not limited to a portable computer diskette, a hard
disk, a random access memory (RAM), a read-only memory (ROM), an
erasable programmable read-only memory (EPROM or Flash memory), a
portable compact disc read-only memory (CD-ROM), a digital
versatile disc (DVD), an optical storage device, a magnetic storage
device, a holographic storage medium, a micromechanical storage
device, or any suitable combination of the foregoing. In the
context of this document, a computer readable storage medium may be
any tangible medium that can contain, and/or store computer
readable program code for use by and/or in connection with an
instruction execution system, apparatus, or device.
[0075] The computer readable medium may also be a computer readable
signal medium. A computer readable signal medium may include a
propagated data signal with computer readable program code embodied
therein, for example, in baseband or as part of a carrier wave.
Such a propagated signal may take any of a variety of forms,
including, but not limited to, electrical, electro-magnetic,
magnetic, optical, or any suitable combination thereof. A computer
readable signal medium may be any computer readable medium that is
not a computer readable storage medium and that can communicate,
propagate, or transport computer readable program code for use by
or in connection with an instruction execution system, apparatus,
or device. Computer readable program code embodied on a computer
readable signal medium may be transmitted using any appropriate
medium, including but not limited to wireless, wireline, optical
fiber cable, Radio Frequency (RF), or the like, or any suitable
combination of the foregoing
[0076] In one embodiment, the computer readable medium may comprise
a combination of one or more computer readable storage mediums and
one or more computer readable signal mediums. For example, computer
readable program code may be both propagated as an electro-magnetic
signal through a fiber optic cable for execution by a processor and
stored on RAM storage device for execution by the processor.
[0077] Computer readable program code for carrying out operations
for aspects of the present invention may be written in any
combination of one or more programming languages, including an
object oriented programming language such as Java, Smalltalk, C++
or the like and conventional procedural programming languages, such
as the "C" programming language or similar programming languages.
The computer readable program code may execute entirely on the
user's computer, partly on the user's computer, as a stand-alone
computer-readable package, partly on the user's computer and partly
on a remote computer or entirely on the remote computer or server.
In the latter scenario, the remote computer may be connected to the
user's computer through any type of network, including a local area
network (LAN) or a wide area network (WAN), or the connection may
be made to an external computer (for example, through the Internet
using an Internet Service Provider).
[0078] The program code may also be stored in a computer readable
medium that can direct a computer, other programmable data
processing apparatus, or other devices to function in a particular
manner, such that the instructions stored in the computer readable
medium produce an article of manufacture including instructions
which implement the function/act specified in the schematic
flowchart diagrams and/or schematic block diagrams block or
blocks.
[0079] The program code may also be loaded onto a computer, other
programmable data processing apparatus, or other devices to cause a
series of operational steps to be performed on the computer, other
programmable apparatus or other devices to produce a computer
implemented process such that the program code which executed on
the computer or other programmable apparatus provide processes for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks.
[0080] Reference throughout this specification to "one embodiment,"
"an embodiment," or similar language means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
present invention. Thus, appearances of the phrases "in one
embodiment," "in an embodiment," and similar language throughout
this specification may, but do not necessarily, all refer to the
same embodiment. Similarly, the use of the term "implementation"
means an implementation having a particular feature, structure, or
characteristic described in connection with one or more embodiments
of the present disclosure, however, absent an express correlation
to indicate otherwise, an implementation may be associated with one
or more embodiments.
[0081] The present disclosure may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative and not restrictive. The scope of
the disclosure is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *