U.S. patent application number 11/650084 was filed with the patent office on 2008-07-10 for method and system for regenerating exhaust system filtering and catalyst components using variable high engine idle.
Invention is credited to Matthew Thomas Baird, Jason Thomas Barton.
Application Number | 20080163610 11/650084 |
Document ID | / |
Family ID | 39477826 |
Filed Date | 2008-07-10 |
United States Patent
Application |
20080163610 |
Kind Code |
A1 |
Baird; Matthew Thomas ; et
al. |
July 10, 2008 |
Method and system for regenerating exhaust system filtering and
catalyst components using variable high engine idle
Abstract
A method and system for regenerating particulate filters,
catalyzed soot filters, and NOx adsorber catalysts for a vehicle
having a compression ignition engine.
Inventors: |
Baird; Matthew Thomas;
(Canton, MI) ; Barton; Jason Thomas; (Canton,
MI) |
Correspondence
Address: |
RADER, FISHMAN & GRAUER PLLC
39533 WOODWARD AVENUE, SUITE 140
BLOOMFIELD HILLS
MI
48304-0610
US
|
Family ID: |
39477826 |
Appl. No.: |
11/650084 |
Filed: |
January 5, 2007 |
Current U.S.
Class: |
60/295 ;
60/286 |
Current CPC
Class: |
F02D 41/1467 20130101;
F01N 3/035 20130101; F01N 3/0821 20130101; Y02A 50/20 20180101;
F01N 3/0842 20130101; F02D 41/1446 20130101; Y02A 50/2325 20180101;
F02D 2041/228 20130101; Y02T 10/26 20130101; Y02T 10/12 20130101;
F02D 2041/026 20130101; F02D 41/083 20130101; F02D 41/0245
20130101 |
Class at
Publication: |
60/295 ;
60/286 |
International
Class: |
F01N 3/023 20060101
F01N003/023 |
Claims
1. A method of regenerating particulate filters, catalyzed soot
filters, Selective Catalytic Reduction systems and NOx adsorber
catalysts for a vehicle equipped with a compression ignition engine
having an engine central module (ECM) and an integrated
starter/alternator/flywheel/retarder assembly, comprising: sensing
the condition of the particulate filters, catalyzed soot filters,
and NOx adsorber catalysts and generating an initiate cleaning
cycle signal upon sensing that the filters and catalysts require
cleaning; monitoring operation of the engine and the vehicle to
determine whether the engine is idling and whether the vehicle is
stopped and generating an engine idling/vehicle stopped signal;
receiving the initiate cleaning cycle signal and the engine
idling/vehicle stopped signal; sensing the temperature of an
exhaust gas stream and generating a low temperature signal upon
sensing that the exhaust gas temperature is insufficient for
regeneration of the filters; sensing the ambient air temperature of
incoming air into a turbo compressor on the engine. initiating
engine control parameter adjustments based upon ambient air
temperature and/or exhaust gas temperature to increase or decrease
engine speed and exhaust gas temperature to regenerate the filters;
resuming normal engine idle operating parameters when filters are
regenerated.
2. The method of claim 1, wherein sensing the condition of the
filter is accompanied by sensing back pressure in the exhaust
system.
3. The method of claim 2, wherein the cleaning cycle is initiated
when the exhaust back pressure exceeds a pre-determined level, and
ceases when the exhaust system back pressure is below a second
pre-determined level.
4. The method of claim 1, wherein the cleaning cycle is initiated
when a the ECM, based upon a modeled approximation of soot
initiates the particulate filter regeneration cycle, and the
particulate filter regeneration cycle ceases based upon the modeled
approximation of soot.
5. The method of claim 1, further comprising a NOx adsorber
catalyst by adjusting the air/fuel ratio.
6. The method of claim 1, wherein the engine operating parameters
adjusted by the engine central module are fueling and timing
parameters.
7. The method of claim 1, further comprising actuating a warning
light in response to the engine control module receiving the signal
to initiate a regeneration cycle.
8. The method of claim 7, wherein upon activating the warning
light, the engine central module initiates steps such as engine
derate or possible engine shut down unless an operator initiates
the regeneration cycle.
9. The method of claim 8, further comprising actuating a manual
switch by the operator upon activation of the warning light.
10. A system for regenerating particulate filters, catalyzed soot
filters, Selective Catalytic Reduction systems, and NOx absorber
catalysts for a compression ignition engine of a vehicle,
comprising: a starter; an alternator; a flywheel; a retarder,
wherein the starter, alternator, flywheel and retarder are combined
as an integrated assembly; a load bank heater disposed in an
exhaust pipe; and an engine control module adapted to receive a
signal to initiate a regeneration cycle, wherein the engine control
module senses exhaust gas temperature and turbo compressor inlet
ambient air temperature adjusts engine operating parameters after
receiving the initiate regeneration cycle signal when the vehicle
is at rest and the engine is idling, wherein the signal to initiate
the regeneration cycle includes a desulfation cycle of a NOx
absorber catalyst that is initiated in response to signals received
from at least one exhaust NOx sensor, at least one exhaust gas
temperature sensor, and at least one air/fuel ratio sensor by the
engine control module.
11. The system of claim 10 wherein the exhaust gas temperature
sensor generates a low temperature signal indicating that the
exhaust temperature is below a predetermined level that is
sufficient for regeneration, wherein the load bank heater is
activated that raises the temperature of the exhaust in conjunction
with increasing the load on the engine applied by the integrated
assembly, wherein the engine control module brings the engine to a
specified operating speed.
12. The system of claim 10 wherein the signal to initiate a
regeneration cycle for a filter is generated by a sensor in the
exhaust that monitors exhaust back pressure.
13. The system of claim 10, wherein the cleaning cycle is initiated
when a the ECM, based upon a modeled approximation of soot
initiates the particulate filter regeneration cycle, and the
particulate filter regeneration cycle ceases based upon the modeled
approximation of soot.
14. The system of claim 10 wherein during the desulfation cycle of
a NOx absorber catalyst the engine operating parameter adjusted is
the air/fuel ratio.
15. The system of claim 10 wherein the engine operating parameters
adjusted by the engine control module are fueling and timing
parameters.
16. The system of claim 10 wherein a warning light is activated in
response to the engine control module receiving the signal to
initiate a user requested regeneration cycle.
17. The system of claim 16 wherein upon activating the warning
light, the engine control module disables the engine unless an
operator initiates the regeneration cycle.
18. The system of claim 16 wherein the operator activates the
regeneration cycle by actuating a manual switch upon activation of
the warning light.
19. A method of regenerating particulate filters, catalyzed soot
filters, Selective Catalytic Reduction systems and NOx adsorber
catalysts for a vehicle equipped with a compression ignition engine
having an engine central module (ECM) and an integrated
starter/alternator/flywheel/retarder assembly, comprising: a)
determining whether the engine is idling; b) determining whether an
engine user is requesting regeneration; c) determining whether it
is acceptable to initiate regeneration; d) determining ambient
temperature of air to inlet of turbo air compressor; e) elevating
engine rpm to a desired engine rpm based upon ambient temperature
and initiate regeneration and desulfation; f) determining whether
the exhaust gas temperature is sufficient to regenerate the
particulate filter; and g) varying the engine speed using ambient
air temperature until the exhaust gas temperature is sufficient to
regenerate the particulate filter
20. The method off claim 19, wherein if it is determined not to be
acceptable to initiate regeneration, engine idle is continued, and
where if the exhaust temperature is determined to be sufficient to
regenerate particulate filter, engine speed is continued at a
desired rpm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a system and method of
regenerating particulate diesel engine exhaust filters.
[0002] The present invention relates to a system and method of
regenerating diesel engine exhaust system particulate filters and
catalysts.
[0003] The present invention further relates to a system and method
of regenerating diesel engine exhaust system particulate filters
and catalysts, as well as catalyzed and uncatalyzed cordierite,
silicon carbide and sintered and unsintered substrates.
[0004] The present invention further relates to a system and method
of regenerating diesel engine exhaust system particulate filters
and catalysts, as well as catalyzed and uncatalyzed cordierite,
silicon carbide and sintered and unsintered substrates while
running the diesel engine at lower rpms to save on fuel costs and
reduce noise.
BACKGROUND
[0005] Diesel engine exhaust systems include particulate filters,
catalyst soot filters, NOx adsorber catalysts, and selective
catalytic reduction (SCR) systems that clean exhaust and reduce
engine emissions. There is a need in the particulate filter aspects
of the exhaust system to oxidize the carbon particulate soot
captured by the filter. With regard to catalyst soot filters, NOx
adsorber catalysts, and SCRs, there is a need to regenerate and
desulfate exhaust system components on a regular basis for
efficient operation.
[0006] Regeneration of diesel particulate filters requires heating
the filters to temperatures of approximately 500.degree. C. to
650.degree. C. for a period range of about 10 to 60 minutes,
depending upon the soot quantity within the diesel particulate
filter. Regeneration of catalyzed soot filters requires heating the
filters to temperatures of approximately 400.degree. C. for a
period of about 10 minutes. Desulfation of NOx adsorbers requires
heating the catalysts to temperatures of approximately 700.degree.
C. for at least 5 minutes while operating the engine with a rich
air/fuel mixture (excess fuel/no excess oxygen), that produces
exhaust gas with higher concentrations of unburned hydrocarbons and
carbon monoxide, and no oxygen. The prior art has proposed
maintaining high catalyst temperatures by locating the catalyst
components close to the engine turbocharger turbine outlet. This
approach is not practical in on-highway vehicles due to space
constraints.
[0007] One preferred way to perform a regeneration cycle is to use
the engine operation heat and the exhaust temperature during normal
duty cycles of the engine operation, such as over the road
operation of the engine, to heat the filter and catalyst components
during the on road duty cycle to regenerate the diesel engine
particulate filters, NOx adsorbers catalysts, SCRs and other
exhaust system components that require regeneration or
desulfation.
[0008] Given certain duty cycles where over the road regeneration
of the diesel engine particulate filter, NOx adsorber catalysts,
SCR's, catalyzed and uncatalyzed silicon carbide, and sintered and
unsintered substrates in an exhaust system is not possible, the
operator must perform a stationary parked regeneration so that the
soot can be oxidized within the operator's diesel particulate
filer. One way to perform such a regeneration cycle is to heat the
filter and catalyst components while the vehicle is at rest, for
example, during a refueling stop or an overnight stop. High exhaust
temperatures are most effectively generated by loading the engine,
however, it is difficult to adequately load an engine while a
vehicle is at rest. The only loads on the engine when a vehicle is
at rest are electrical loads such as those associated with lights
and air conditioning systems and mechanical loads related to the
operation of an air compressor, cooling fan and the idling torque
load of the engine. These loads are negligible compared to the road
loads encountered when a loaded vehicle is climbing a grade.
[0009] There is a need for an effective system for producing higher
temperatures needed for regenerating exhaust system particulate
filter and catalyst components without unduly penalizing fuel
economy.
[0010] These and other problems are addressed by applicant's
invention and summarized below.
SUMMARY OF THE INVENTION
[0011] According to one aspect of the present invention, a system
for regenerating particulate filters and catalyst soot filters is
provided for compression ignition engines. The system includes an
integrated assembly comprising a starter, an alternator, a flywheel
and a retarder. An engine control module is adapted to receive a
signal for initiating a regeneration cycle when the vehicle is at
rest and the engine is idling. In response to receiving the signal
to initiate a regeneration cycle, the control module. The engine
control module also adjusts engine operating parameters.
[0012] The system also includes a sensor for sensing the
temperature of the exhaust. When the sensor generates a signal
indicating that the exhaust temperature is insufficient for
regeneration, raises the temperature of the exhaust and also
increases the load on the engine. When the engine control module
(ECM) receives a request for a high idle regeneration, the ECM
immediately activates the engine fan to increase load on the engine
and it immediately ramps up to an elevated rpm. In this regard, the
fan is activated as a function of exhaust temperature. When a need
for an increased load is sensed, the ECM activates the fan, and
when the need for increased load is not sensed, the fan is not
activated. Thus, the fan activation can be a function of load and
exhaust temperature, and approximated ambient air temperature, and
activating the fan induces a higher exhaust temperature and this is
a more effective way of converting hydrocarbon across the Diesel
Oxidation Catalyst (DOC). Upon reaching the elevated rpm operation,
the ECM will wait for an acceptable temperature before initiating
thermal management mode to avoid potential white smoke issues.
Thermal Management Mode (TMM) raises the exhaust temperature up to
an acceptable temperature where hydrocarbon can be converted across
the DOC effectively.
[0013] Preferably, the signal to initiate a regeneration cycle for
a filter may be generated by a sensor that monitors particulate
load on the filters and engine operating history to determine when
regeneration of the diesel particulate filter is required. Thus,
the initial signal to regenerate the diesel engine particulate
filter occurs automatically without any operator input or
knowledge.
[0014] In another embodiment, if regeneration cycle cannot be
accomplished in normal operating cycle of the engine, or
regeneration of the filter cannot occur automatically, a warning
light may be activated alerting the operator that a stationary
parked regeneration or a high idle regeneration cycle is required.
If the operator ignores the warning light, the ECM may activate any
combination of engine derate, or the check engine light, or the
stop engine light or shut down the engine to protect the
filter.
[0015] The signal to initiate a desulfation cycle of a NOx adsorber
catalyst is initiated in response to signals received from exhaust
NOx sensors, temperature sensors, and air/fuel ratio sensors that
are monitored by the engine control module during the desulfation
cycle of a NOx adsorber catalyst. Fueling and timing engine
operating parameters can be adjusted by the engine control module
for desulfation and regeneration.
[0016] Referring to another aspect of the invention, a method of
regenerating particulate filters, catalyzed soot filters and NOx
adsorber catalysts for a vehicle having a compression ignition
engine is provided. The compression ignition engine has an engine
control module and an integrated
starter/alternator/flywheel/retarder. The method comprises sensing
the condition of the particulate filter, catalyzed soot filters,
and NOx adsorber catalysts and generating an initiate cleaning
cycle signal upon sensing that the filters or the catalysts require
a parked regeneration. Operation of the engine and the vehicle are
monitored to determine whether the engine is idling and whether the
vehicle is stopped, whereupon an engine idling/vehicle stop signal
is generated. Upon receiving the initiate cleaning engine cycle
signal and the engine idling/vehicle stop signal, the engine
control module adjusts engine control parameters to bring the
engine to a specified operating speed. The physical temperature on
the air intake tubing of the vehicle before the inlet to the air
compressor of the turbocharger is also sensed. The ECM uses the
ambient air temperature to estimate at what engine speed the parked
regeneration cycle should be performed. If the current engine speed
is not successful at creating an exhaust temperature at a required
elevated temperature to convert hydrocarbon across the DOC, then
the controller can elevate the engine speed further so that the
appropriate elevated exhaust temperature can be achieved. In
addition, if the temperature is too high, the ECM can lower engine
rpm if needed to save fuel.
[0017] Upon sensing that the exhaust gas temperature is
insufficient for the regeneration of filters, a low temperature
signal is generated. When the engine control module receives such a
low temperature signal, the physical temperature on the air intake
tubing of the vehicle before the inlet to the compressor to the air
turbocharger is sensed. Fueling strategies are provided in a data
look up table in the engine control module based upon the
temperature of the ambient air entering the compressor. The lower
the sensed temperature of the ambient air, the more fuel is allowed
to the engine, thereby causing the engine speed to increase. The
increase in engine speed increases the heat of the exhaust gas
stream which passes over the filter, cleaning the soot and
particulates. Once the filter is clean, the engine control module
senses the condition by a pressure sensor. When fuel is being dosed
and oxidized across the DOC, soot in the filter burns as a result
of elevated temperatures. In addition, the ECM contains data that
approximates how much soot is burned from the particulate filter
based upon the exhaust gas temperature and the engine air to fuel
ratio at the current engine operating condition, and, if the amount
of soot burned approximates the amount of soot that should have
been burned, fueling is reduced and the process is completed.
[0018] According to other aspects of the method of the present
invention, a signal to initiate a regeneration cycle is generated
by a sensor that monitors exhaust gas for soot and particulates and
compares that amount to trigger thresholds in an internal table
within the ECM and can also be initiated based on a model that
approximates how much soot/particulate matter is exiting the
engine. For example, these models may be based upon speed/load
particulate matter tables. A signal to initiate a desulfation cycle
may be generated based upon outputs from exhaust NOx sensors,
temperature sensors, and air/fuel ratio sensors that are received
by the engine control module that in turn initiates desulfation of
an NOx adsorber catalyst. The engine control module may also adjust
the air/fuel ratio when desulfating a NOx adsorber catalyst.
Fueling and timing may also adjust the air/fuel ratio engine
operating parameters may be adjusted by the engine control
module.
[0019] These and other aspects of the invention will be better
understood in view of the attached drawings and the following
detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic representation of a compression
ignition engine having an exhaust system component regeneration
system according to the present invention.
[0021] FIG. 2 is a flow charting showing the method regenerating
filters according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Referring now to the drawings, wherein like numerals refer
to like structures, and particularly to FIG. 1, a compression
ignition engine 10 for an on-highway vehicle 12 is shown
schematically. The engine 10 includes an engine control module 14
that controls operation of the engine 10 and also controls exhaust
component regeneration and desulfation according to the present
invention as described below.
[0023] Exhaust manifold sensors 16, exhaust sensors 17 located
before the aftertreatment 19 and tail pipe sensors 18 provide
exhaust temperature and other gas information to the engine control
module (ECM) 14 that is used in controlling exhaust component
regeneration. Those skilled in the art will recognize that while
sensors 16 are depicted as manifold sensors, the sensors could be
located in the engine exhaust piping upstream of the after
treatment. The exhaust manifold sensors 16 may provide information
regarding NOx levels, air/fuel ratios (.lamda.), temperature, and
pressure. More specifically, the exhaust manifold sensors 16,
exhaust sensors 17 and pipe sensors 18 may provide information
regarding NOx, (.lamda.), and temperature that enable the ECM to
detect an impending need for regeneration, or whether the system
has acceptable temperatures to effect particulate filter
regeneration. The ECM may also monitor other engine operating
parameters to determine the need for regeneration, such as engine
load and engine rpm to detect an impending need for regeneration. A
warning light 26 is activated upon detecting a need for
regeneration of a particulate filter 20, catalyzed soot filter 22,
or NOx adsorber catalyst 24. Illumination of the warning light
prompts the operator to actuate a switch 28 to activate the
regeneration/desulfation cycle.
[0024] When the vehicle stops for fuel or for any other reason, the
engine 10 normally continues to idle. At this time, with the
vehicle stopped, the ECM controls fueling, timing, governing and
other engine operating parameters as required to bring the engine
to a specified operating speed. If a particulate filter, catalyzed
soot filter, or NOx adsorber catalyst is to be regenerated, the
air/fuel ratio is also controlled accordingly.
[0025] Sensors 16 and 18 provide information regarding the exhaust
gas temperature to the ECM. If the exhaust gas temperature is
insufficient to effect regeneration of the particulate filter or
the catalyzed soot filter or the NOx adsorber catalyst, sensor 30
in air tubing inlet 32 to the turbocharger 34 provides information
to the ECM regarding the temperature of the incoming ambient air.
Fuel delivery data tables based upon ambient air temperature are
provided within the ECM. The fuel air ratio delivery to the engine
is adjusted based upon the ambient air temperature so that engine
speed is increased. The increased engine speed results in an
increased exhaust gas stream temperature. As the temperature in the
exhaust gas stream increases to the temperature necessary to effect
particulate filter, catalytic soot filter or NOX adsorber filter
regeneration, the ECM senses the condition of the filters and, when
they have regenerated, the ECM adjusts the fuel/air ratio delivery
each toward normal idle operation so that the operator will not
suffer an unduly large fuel economy penalty for filter cleaning
operation. Likewise, if temperature is high, it is contemplated
that the ECM could reduce engine speed so that fuel economy is
improved during the regeneration process. At the end of the
regeneration process, the ECM causes the engine speed to resume its
normal base idle.
[0026] If the operator fails during a subsequent fuel stop to
initiate a regeneration/desulfation cycle after the warning light
is illuminated, the ECM may disable the vehicle. The ECM can
disable the vehicle by precluding gear engagement in the
transmission or by disabling the engine throttle. The ECM may also
take other measures to prevent operation of the vehicle until the
regeneration/desulfation cycle is initiated by the operator. For
example, if the operator fails to initiate a
regeneration/desulfation cycle, the ECM may limit fueling to the
engine and thereby reduces operation performance of the vehicle.
Preferably, if the ECM detects that a regeneration/desulfation
cycle is required, a warning light is activated alerting the
operator of the need to initiate a regeneration/desulfation cycle.
If the operator continues to ignore the warning light, the ECM may
derate the engine to protect the filter and reduce the operability
of the vehicle. If the engine operator continues to ignore the
warning light, the ECM may begin initiating the shut-down of the
engine. The operator will have the option of overriding the
shutdown. Alternatively, the system may activate an alarm or flash
the warning light to provide further advice to the operator as to
the necessity of performing the regeneration/desulfation cycle.
[0027] FIG. 2 is a schematic of the steps the ECM initiates to
effect the active particulate catalytic soot filter and NOx
adsorber regeneration of the present invention. Method 36 is
initiated at start 38. Step 40 is determining whether the engine is
idling. If yes, step 42 is determining whether the engine operator
requests filter regeneration. Step 44 is determining whether it is
acceptable to regenerate the filters. If no, step 46 is to continue
idle operation. If yes, step 48 is determining ambient air
temperature entering at the compressor. Step 50 is elevating engine
rpm to a desired rpm based upon ambient temperature and begin
regeneration/desulfation of the filters and NOx adsorber/catalysts.
Step 52 is determining whether the exhaust temperature is
sufficient to regenerate the particulate filter. If yes, at step 54
the ECM continues engine speed at the desired rpm. If no, step 56
is varying the engine speed using ambient air temperature until the
exhaust gas stream temperature is sufficient to regenerate the
filters. Once the filters are regenerated, engine speed is
decreased and the normal idle fuel delivery is resumed. It is also
an integral part of this invention that the range of engine seed
operation to effect regeneration is kept within a range that will
be as low as possible to reduce engine noise to a minimum and save
fuel during the regeneration cycle. A warning light may optimally
be provided to alert the operator when the filters require
cleaning.
[0028] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
* * * * *