U.S. patent application number 12/645566 was filed with the patent office on 2011-06-23 for power system having additive injector.
This patent application is currently assigned to Caterpillar Inc.. Invention is credited to Brett Bailey, Clifford Eugene Cotton, III, Christopher J. Rynders, JR..
Application Number | 20110146234 12/645566 |
Document ID | / |
Family ID | 44149137 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110146234 |
Kind Code |
A1 |
Rynders, JR.; Christopher J. ;
et al. |
June 23, 2011 |
POWER SYSTEM HAVING ADDITIVE INJECTOR
Abstract
A power system is provided. The power system includes a power
source configured to generate a flow of exhaust including
particulate matter. The power system also includes a fuel supply
line connecting a fuel supply and the power source, and being
configured to direct a fuel flow from the fuel supply to the power
source. An additive injector is configured to inject an additive
into the fuel flow. An ionization device is at least partially
disposed within the flow of exhaust, and is configured to apply a
charge to the particulate matter and the additive. A particulate
filter is configured to remove the particulate matter and the
additive from the flow of exhaust.
Inventors: |
Rynders, JR.; Christopher J.;
(Peoria, IL) ; Cotton, III; Clifford Eugene;
(Bradford, IL) ; Bailey; Brett; (Effingham,
SC) |
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
44149137 |
Appl. No.: |
12/645566 |
Filed: |
December 23, 2009 |
Current U.S.
Class: |
60/274 ;
60/275 |
Current CPC
Class: |
F02D 41/1448 20130101;
F02D 41/0025 20130101; F01N 2430/04 20130101; F02D 41/029 20130101;
F01N 3/0275 20130101; F02D 41/1446 20130101 |
Class at
Publication: |
60/274 ;
60/275 |
International
Class: |
F01N 3/01 20060101
F01N003/01 |
Claims
1. A power system, comprising: a power source configured to
generate a flow of exhaust including particulate matter; a fuel
supply line connecting a fuel supply and the power source, and
being configured to direct a fuel flow from the fuel supply to the
power source; an additive injector configured to inject an additive
into the fuel flow; an ionization device at least partially
disposed within the flow of exhaust, and being configured to apply
a charge to the particulate matter and the additive; and a
particulate filter configured to remove the particulate matter and
the additive from the flow of exhaust.
2. The power system of claim 1, wherein the additive injector is
located upstream of the power source.
3. The power system of claim 1, further including: an additive
supply; and a pump configured to draw the additive from the
additive supply and direct the additive to the additive
injector.
4. The power system of claim 1, wherein the additive is an
iron-based additive.
5. The power system of claim 1, further including a sensor in fluid
communication with the flow of exhaust and being configured to
measure a parameter of the flow of exhaust.
6. The power system of claim 5, wherein the sensor includes at
least one of a temperature sensor or a pressure sensor, and the
parameter is at least a temperature of the flow of exhaust or a
pressure of the flow of exhaust.
7. The power system of claim 1, further including a load sensor
associated with the particulate filter and being configured to
measure a load of the particulate matter.
8. The power system of claim 1, further including a first charging
device associated with the ionization device and being configured
to provide the charge applied to the particulate matter and the
additive.
9. The power system of claim 8, wherein the charge applied to the
particulate matter and the additive is a first charge, the power
system further including a second charging device associated with
the particulate filter, and being configured to apply a second
charge to the particulate filter.
10. The power system of claim 9, further including a controller
associated with the additive injector and being configured to
control the injection of the additive into the fuel flow.
11. The power system of claim 10, wherein the controller is further
configured to control the first and second charges.
12. A method of removing particulate matter from a flow of exhaust,
comprising: directing a flow of fuel into a power source; injecting
an additive into the flow of fuel; combusting the fuel to produce
the flow of exhaust, wherein the flow of exhaust includes the
particulate matter and the additive; applying a like charge to the
particulate matter and the additive; and directing the flow of
exhaust through a particulate filter.
13. The method of claim 12, further including controlling the
injection of the additive based on a parameter associated with the
flow of exhaust.
14. The method of claim 13, wherein the parameter is indicative of
at least one of a temperature of the flow of exhaust and a pressure
of the flow of exhaust.
15. The method of claim 12, further including controlling the
injection of the additive based on a load of the particulate matter
within the particulate filter.
16. The method of claim 12, further including applying a charge to
the particulate filter, the charge applied to the particulate
filter having a polarity opposite to the polarity of the like
charge applied to the particulate matter and the additive.
17. A machine, comprising: a power source configured to combust
fuel and generate a flow of exhaust including particulate matter; a
fuel supply line configured to direct a fuel flow from a fuel
supply to the power source; an additive injector configured to
inject an additive into the fuel flow; an ionization device at
least partially disposed within the flow of exhaust, and being
configured to apply a first charge having a first polarity to the
particulate matter and the additive; a particulate filter
configured to remove the particulate matter and the additive from
the flow of exhaust; and a charging device configured to apply a
second charge to the particulate filter, the second charge having a
second polarity opposite to the first polarity.
18. The machine of claim 17, wherein the additive injector is
located upstream of the power source.
19. The machine of claim 17, wherein the additive is an iron-based
additive.
20. The machine of claim 17, further including: at least one sensor
in fluid communication with the flow of exhaust and being
configured to measure a parameter of the flow of exhaust; at least
one sensor associated with the particulate filter and being
configured to measure a parameter of the particulate filter; and a
controller associated with the additive injector and being
configured to control the injection of the additive into the fuel
flow based on at least one of the parameter of the flow of exhaust
and the parameter of the particulate filter.
Description
TECHNICAL FIELD
[0001] The present disclosure relates generally to a power system
and, more particularly, to a power system having an additive
injector.
BACKGROUND
[0002] Internal combustion engines, including diesel engines,
exhaust a complex mixture of potential air pollutants. These air
pollutants may include solid material known as particulate matter
or soot. Due to increased environmental concerns, diesel engine
exhaust emission standards have become more stringent. The amount
of particulate matter emitted from an engine may be regulated
depending on the type of engine, size of engine, and/or class of
engine.
[0003] One method implemented by engine manufacturers to comply
with the regulation of particulate matter exhausted to the
environment has been to remove the particulate matter from the
exhaust flow of an engine using a particulate matter collection
device, for example, a particulate trap or diesel particulate
filter (DPF). A DPF is a filter designed to trap particulate matter
in a filter substrate, which may include, for example, wire mesh or
ceramic honeycomb filtering media. Though effective in reducing
relatively larger-sized particulate matter from the exhaust, the
filtering media may not be efficient in trapping relatively
smaller-sized particulate matter.
[0004] Over time, the particulate matter may accumulate on the
filtering media, and may block the exhaust passageway, thereby
increasing pressure in the exhaust, and reducing engine
performance. The DPF can be regenerated by raising the temperature
of the exhaust, for example, through controlling the engine
combustion or a heating device associated with the DPF, to burn off
the particulate matter attached to the filter media. Typically, a
DPF regeneration process lasts for a predetermined period of time,
for example, 10 minutes. In some cases, when the distribution of
the particulate matter on the filtering media is not uniform, some
particulate matter may remain unburned by the time the regeneration
process is terminated.
[0005] Various regeneration techniques may be employed to manage
the reduction of the particulate matter in engine exhaust. For
example, U.S. Pat. No. 6,488,725 ("the '725 patent") issued to
Vincent et al. on Dec. 3, 2002, describes a method of supplying an
iron-containing fuel soluble additive for use in the regeneration
of a particulate filter trap. The method includes adding an
additive to the fuel prior to or during combustion. In particular,
the supply of additive is added to the fuel at any stage in the
fuel supply chain, or is added via a dosing device on-board the
vehicle to either the fuel, or directly into the combustion chamber
or the inlet system. The additive mixes with the fuel, and the
mixture is combusted to provide a flow of exhaust containing soot
particulates and additives. In operation, the additives reduce the
soot particulate ignition temperature.
[0006] Although the method described in the '725 patent may
suitably regenerate the particulate filter trap, it may be
problematic. For example, if the particulate matter is sufficiently
fine in size, the diesel particulate filter may not be efficient in
trapping the fine particulate matter. Thus, the fine particulate
matter may be discharged directly into the environment, causing
pollution to the environment. Furthermore, the distribution of the
particulate matter and additives on the filter media may not be
uniform. This may result in residual particulate matter remaining
unburned on the filtering media after the regeneration is
terminated, which may adversely affect the exhaust flow and/or the
engine performance.
[0007] The system of the present disclosure is directed toward
improvements in the existing technology.
SUMMARY
[0008] One aspect of the present disclosure is directed to a power
system. The power system includes a power source configured to
generate a flow of exhaust. The power system also includes a fuel
supply line connecting a fuel supply and the power source. The fuel
supply line is configured to direct a fuel flow from the fuel
supply to the power source. An additive injector is configured to
inject an additive into the fuel flow. An ionization device is at
least partially disposed within the flow of exhaust, and configured
to apply a charge to the additive and particulate matter within the
flow of exhaust. A particulate filter is configured to remove the
particulate matter and the additive from the flow of exhaust.
[0009] Another aspect of the present disclosure is directed to a
method of removing particulate matter from a flow of exhaust. The
method includes directing a flow of fuel into a power source. The
method also includes injecting an additive into the flow of fuel
upstream of the power source. The method also includes combusting
the fuel and the additive to produce a flow of exhaust having
particulate matter and additive. The method also includes applying
a charge to the additive and particulate matter by directing the
flow of exhaust through an ionization device. The method further
includes directing the flow of exhaust through a particulate
filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic and diagrammatic illustration of an
exemplary machine having an exemplary disclosed power system.
DETAILED DESCRIPTION
[0011] FIG. 1 schematically illustrates an exemplary machine 5, in
which an exemplary disclosed power system 10 may be employed.
Machine 5 may be any type of machine, for example, a mobile
machine, such as a passenger vehicle, a vocational vehicle, a
farming machine, a mining machine, a construction machine, etc.
Alternatively, machine 5 may be a stationary machine such as, for
example, a power generation machine.
[0012] Power system 10 may include a power source 20 configured to
combust fuel and generate a flow of exhaust including particulate
matter, and an exhaust after-treatment system 30 configured to
treat the flow of exhaust. For the purposes of this disclosure,
power source 20 is depicted and described as a four-stroke diesel
engine. One skilled in the art will recognize that power source 20
may be any type of internal combustion engine such as, for example,
a gasoline engine, a gaseous fuel-powered engine (e.g., a natural
gas engine), or any other type of combustion engine known to one
skilled in the art. Power source 20 may include an engine block
that at least partially defines a plurality of combustion chambers
25. In the illustrated embodiment, power source 20 includes four
combustion chambers. It is contemplated that power source 20 may
include a greater or lesser number of combustion chambers 25 and
that the combustion chambers 25 may be disposed in an "in-line"
configuration, or a "V" configuration, or any other suitable
configuration.
[0013] Power source 20 may draw an air/fuel mixture into each one
of combustion chambers 25 to produce combustion and generate power,
heat, and exhaust. In particular, power source 20 may include an
intake manifold 35 to supply the air/fuel mixture to power source
20. Intake manifold 35 may receive fuel from a fuel system 40 and
air from an air supply system (not shown), and may direct a mixture
of the air and fuel to each of combustion chambers 25.
[0014] Fuel system 40 may be configured to deliver fuel to power
source 20 for combustion. Fuel system 40 may include a fuel supply
45, a pump 55, and a fuel supply line 50 configured to direct a
fuel flow from fuel supply 45 to power source 20. Fuel supply line
50 may be configured to direct a fuel flow from fuel supply 45 to
intake manifold 35 of power source 20. Pump 55 may be disposed
within fuel supply line 50, and may be configured to draw an amount
of fuel from fuel supply 45, pressurize the fuel, and direct the
pressurized fuel to intake manifold 35. Alternatively, it is
contemplated that power source 20 may include an injector (not
shown) associated with each of combustion chambers 25 and being
configured to inject fuel into each of combustion chambers 25.
[0015] Power system 10 may further include devices that provide a
supply of additive solution to the fuel flow prior to or during
combustion. Specifically, power system 10 may include an additive
supply 60 configured to store and supply an amount of additive, and
an additive injector 70 configured to inject additive into the fuel
flow supplied to power source 20. Power system 10 may also include
a pump 65 configured to pump the additive from additive supply 60
to additive injector 70. Pump 65 may be any kind of high-precision,
metered, low-flow rate pump. Pump 65 may be a diaphragm pump or any
other pump known in the art. Additive injector 70 may be disposed
at any suitable location within power system 10. For example,
additive injector 70 may be disposed at least partially within fuel
supply line 50, at least partially within fuel supply 45, adjacent
intake manifold 35, or adjacent combustion chambers 25. Additive
may be injected by additive injector 70 into the fuel supplied to
power source 20. For example, additive may be injected into fuel
supply line 50, fuel supply 45, intake manifold 35, combustion
chambers 25, or any suitable location within fuel system 40 or
power source 20 prior to or during combustion. As illustrated in
FIG. 1, additive injector 70 may be located upstream of power
source 20, and may inject the additive into intake manifold 35
upstream of power source 20. It is contemplated that additive
injector 70 may be mechanically, hydraulically, or electrically
actuated.
[0016] After-treatment system 30 may be configured to reduce
emissions of harmful gases and particulate matter emitted from
power source 20 after a combustion process. After-treatment system
30 may include an exhaust manifold 85 having exhaust passageways,
each passageway being in fluid communication with one of combustion
chambers 25. After-treatment system 30 may include a passageway 90,
which may be in fluid communication with exhaust manifold 85.
After-treatment system 30 may include various devices within
passageway 90 to reduce harmful gases and particulate matter from
the exhaust. For example, after-treatment system 30 may include a
particulate filter 95 at least partially disposed within passageway
90, and being configured to trap particulate matter as the exhaust
passes therethrough. Although not shown, one skilled in the art may
recognize that after-treatment system 30 may also include a
fuel-fired burner or a heating device associated with particulate
filter 95 for increasing the temperature of the exhaust or the
particulate matter trapped within particulate filter 95 to oxidize
the particulate matter during a regeneration process. In some
embodiments, the temperature of the exhaust may be increased
through control of the engine combustion. In such embodiments, no
fuel-fired burner or heating device may be included in
after-treatment system 30. It is contemplated that after-treatment
system 30 may include other components known in the art, such as,
for example, a selective catalytic reductant device, a NOx trap, a
SOx reduction device, etc.
[0017] Particulate filter 95 may be any variety of particulate
filter, such as, for example, a sintered metal fiber flow-through
filter, cordierite or silicon carbide wall-flow filter, or any
other particulate filter known in the art. Particulate filter 95
may include a housing 100 and a filter substrate 105 disposed at
least partially within housing 100. Filter substrate 105 may
include a wire mesh medium, a ceramic honeycomb filtration medium,
or any other suitable medium known in the art. As the flow of the
exhaust passes through the filtration medium, the particulate
matter, for example, unburned hydrocarbons, may impinge against and
be blocked by the filtration medium. Over time, the particulate
matter may build up on the surfaces of filter substrate 105 and the
filtration medium may become saturated. This build-up of the
particulate matter may reduce the flow of exhaust through
particulate filter 95 and may adversely affect the engine
performance.
[0018] Power system 10 may include a control system 120 configured
to control the operation of power system 10. Control system 120 may
include a controller 80, which may be an existing machine control
module or a stand-alone controller. Controller 80 may be associated
with various systems and devices of power system 10. For example,
controller 80 may be associated with at least one of power source
20, after-treatment system 30, and fuel system 40. Controller 80
may control operations of power source 20, exhaust after-treatment,
and fuel delivery. For another example, controller 80 may also be
associated with at least one of additive supply 60, additive
injector 70, and pump 65. Controller 80 may be configured to
control the injection of the additive into the fuel supplied to
power source 20. Controller 80 may regulate the amount and the
timing of the injection of additive through controlling at least
one of additive supply 60, additive injector 70, and pump 65.
[0019] Control system 120 may include at least one sensor in fluid
communication with the flow of exhaust and being configured to
measure a parameter of the flow of exhaust. Control system 120 may
also include at least one sensor associated with particulate filter
95 and being configured to measure a parameter of particulate
filter 95. For example, control system 120 may include a
temperature sensor 130. Temperature sensor 130 may be at least
partially disposed within passageway 90, for example, upstream or
downstream of particulate filter 95, and may be in fluid
communication with the flow of exhaust. Temperature sensor 130 may
measure a temperature of the flow of exhaust, and may generate a
signal indicative of the measured temperature. Temperature sensor
130 may send the signal to controller 80 for analysis. In some
embodiments, temperature sensor 130 may also be configured to
measure a temperature associated with particulate filter 95 or a
temperature of the particulate matter accumulated on the surfaces
of filter substrate 105. Temperature sensor 130 may be integral
with a part of particulate filter 95, for example, filter substrate
105, or may be disposed adjacent particulate filter 95.
[0020] Control system 120 may include a pressure sensor 135 at
least partially disposed within passageway 90, and being in fluid
communication with the flow of exhaust. Pressure sensor 135 may be
configured to measure a pressure of the exhaust within passageway
90. For example, pressure sensor 135 may be disposed upstream of
particulate filter 95 to monitor a pressure of the exhaust upstream
of particulate filter 95. Pressure sensor 135 may also be disposed
downstream of particulate filter 95, if desired. It is contemplated
that more than one pressure sensor may be located at various
locations within passageway 90.
[0021] Control system 120 may also include a particulate filter
load sensor 125 configured to measure a load of the particulate
matter within particulate filter 95, for example, an amount of the
particulate matter accumulated on the surfaces of filter substrate
105. Load sensor 125 may generate a signal indicative of the load
of the particulate matter, and may send the signal to controller
80. Load sensor 125 may be integrated with or disposed adjacent
particulate filter 95.
[0022] Additionally and/or alternatively, at least one of the
temperature of the exhaust or particulate filter 95, the pressure
of the exhaust within passageway 90, and the load of particulate
filter 95, may be estimated by controller 80 rather than be
measured by sensors. That is, controller 80 may determine the
temperature, pressure, and load associated with the exhaust and/or
particulate filter 95 as a function of variables related to one or
more operating conditions of power source 20 and/or the machine
associated therewith (i.e., virtual sensors). For example, one or
more engine performance maps relating a fueling amount, ignition
timing, power output, engine speed, boost pressure, engine
temperature, an air/fuel ratio, and/or other known parameters may
be stored within a memory of controller 80. Each of these maps may
be in the form of tables, graphs and/or equations and may include a
compilation of data collected from lab and/or field operation of
power source 20. Controller 80 may receive data relating to the
operation of power system 10 and may reference one or more of these
maps in order to estimate a temperature, pressure, and load
associated with the exhaust and/or particulate filter 95 for a
given operating condition of power source 20. In this manner,
controller 80 may measure or estimate temperature data from which
decisions about the regeneration of particulate filter 95 and the
injection of the additive may be made.
[0023] After-treatment system 30 may include an ionization device
140. Ionization device 140 may be at least partially disposed
within exhaust passageway 90 upstream of particulate filter 95.
Ionization device 140 may be connected with a first charging device
145 configured to supply a voltage of a predetermined polarity,
such as a positive voltage, to ionization device 140. As a result,
ionization device 140 may become charged, and may in turn apply a
first charge, for example, a positive charge, to the particulate
matter and the additive particles within the exhaust as the exhaust
passes by ionization device 140. Thus, the particulate matter and
the additive particles may become electrostatically charged with a
like charge, for example, the positive charge.
[0024] After-treatment system 30 may also include a second charging
device 155 configured to apply a second charge to particulate
filter 95. The second charge may have a polarity opposite to that
of the first charge applied to the particulate matter and the
additive particles. Second charging device 155 may be connected
with a suitable portion of particulate filter 95, for example,
filter substrate 105 or housing 100. Second charging device 155 may
supply a voltage to, for example, filter substrate 105 of
particulate filter 95, such that filter substrate 105 of
particulate filter 95 may be electrostatically charged with the
second charge.
[0025] At least one of the first and second charging devices 145
and 155 may be connected with and controlled by controller 80.
Controller 80 may control, for example, the magnitude and polarity
of voltages supplied to ionization device 140 and particulate
filter 95 by controlling first and second charging devices 145 and
155, respectively. In other words, controller 80 may control the
amounts and polarity of charges applied to the particulate matter
and additive particles, and particulate filter 95. Although shown
as separate devices, in some embodiments, at least one of first and
second charging devices 145 and 155 may be integral with controller
80.
INDUSTRIAL APPLICABILITY
[0026] The disclosed system may be applicable to any power system
for reducing the particulate matter generated from combustion and
for facilitating regeneration of a particulate filter. For example,
the disclosed after-treatment system 30 may be applicable to mobile
systems, such as engines that power mobile vehicles, for example,
automobiles, semi-trailer trucks, construction equipment, marine
vessels, etc. After-treatment system 30 may also be applicable to
stationary machines, such as electric power generation sets.
[0027] Power source 20 may combust a mixture of air and fuel to
generate power and exhaust. Fuel system 40 may supply fuel to power
source 20. Pump 55 may draw fuel from fuel supply 45, pressurize
the fuel, and direct the pressurized fuel to intake manifold 35.
The fuel may be mixed with air received from an air supply system
(not shown), and may be directed into combustion chambers 25 for
combustion therein. Power source 20 may output, after combustion, a
flow of exhaust. The flow of exhaust may be discharged from
combustion chambers 25, and directed through exhaust manifold 85 to
after-treatment system 30, where the exhaust is treated. The flow
of exhaust may contain a complex mixture of air pollutants, which
may include particulate matter. The release of particulate matter
into the environment may be reduced by passing the flow of exhaust
through particulate filter 95.
[0028] Additive may be injected into the fuel flow supplied to
power source 20 at a suitable location within power system 10 prior
to or during combustion. The additive may be configured for the
purpose of facilitating the regeneration of particulate filter 95,
for the purpose of improving uniform distribution of the
particulate matter on the surfaces of filter substrate 105, or for
other suitable purposes. The additive may be an iron-based
material, for example, Dicyclopentadienyl iron, or any other
suitable materials. Additive injector 70 may inject a predetermined
amount of additive into the fuel flow supplied to power source 20.
Alternatively, additive injector 70 may inject the additive into
intake manifold 35 or combustion chambers 25. The additive may be
combusted together with the air/fuel mixture within combustion
chambers 25.
[0029] After combustion, the additive may become particles and may
be present within the exhaust together with the particulate matter.
As the exhaust passes by ionization device 140, ionization device
140 may apply an electrical charge, such as, for example, a
positive electrical charge, to the additive particles and the
particulate matter. Controller 80 may control ionization device 140
by controlling the voltage supplied from first charging device 145
to ionization device 140. As a result, the additive particles and
the particulate matter may become electrostatically charged with
like charges of the same polarity, for example, the positive
polarity.
[0030] The charged additive particles and the particulate matter
may repel one another due to the electrostatic force between two
charges with the same polarity. Specifically, the repelling force
may exist between any charged additive particles and any charged
particles of the particulate matter. As a result of the repelling
force, a uniform distribution of the particulate matter and/or the
additive particles within the exhaust may be created. Consequently,
when the particulate matter and/or the additive particles attach to
the surfaces of filter substrate 105, a uniform distribution of the
particulate matter and/or the additive particles on the surfaces of
filter substrate 105 may be achieved. Uniform distribution of the
particulate matter and the additive particles may improve the
efficiency of the regeneration of the particulate matter, reducing
or eliminating residual particulate matter remaining on filter
substrate 105 when a regeneration process is terminated.
[0031] Controller 80 may control second charging device 155 to
apply a counter voltage to a portion of particulate filter 95, for
example, filter substrate 105. In other words, for example, when a
positive voltage is supplied to ionization device 140, a negative
voltage may be supplied to filter substrate 105. Therefore, when
the positively charged particulate matter and the additive
particles arrive at filter substrate 105, the positively charged
particulate matter and the additive particles may be attracted to
the surfaces of negatively charged filter substrate 105 due to the
electrostatic attraction force between the opposite electrical
charges. In such a way, the particulate matter may be better
captured by filter substrate 105. In particular, smaller-sized
particulate matter, which may otherwise escape through the meshes
of filter substrate 105 when not electrostatically charged, may be
captured by filter substrate 105 due to the electrostatic
attraction force between the positively charged particulate matter
and the negatively charged filter substrate 105.
[0032] Controller 80 may control the regeneration of particulate
filter 95, and/or the injection of the additive. For example,
during the operation of power system 10, controller 80 may monitor
the load of particulate matter accumulated on filter substrate 105
by load sensor 125. When load sensor 125 indicates that the
particulate matter load of filter substrate 105 exceeds a
predetermined load threshold, controller 80 may activate a
regeneration process to regenerate particulate filter 95.
Alternatively and/or additionally, controller 80 may monitor the
pressure of the exhaust flow upstream of particulate filter 95
through pressure sensor 135, which may generate a signal indicative
of the pressure of the exhaust flow and send the signal to
controller 80. Controller 80 may determine, based on the measured
pressure of the exhaust flow, whether a regeneration process is
needed to regenerate particulate filter 95. It is contemplated that
controller 80 may also determine whether a regeneration is needed
to regenerate particulate filter 95 based on the temperature of the
exhaust flow and/or the particulate matter captured by filter
substrate 105, as measured by temperature sensor 130. Controller 80
may activate a regeneration based on at least one of the load
measured by load sensor 125, the pressure measured by pressure
sensor 135, and the temperature measured by temperature sensor
130.
[0033] Controller 80 may monitor the temperature of the exhaust
flow, and/or the temperature associated with particulate filter 95,
through temperature sensor 130. Temperature sensor 130 may generate
a signal indicative of the measured temperature and send the signal
to controller 80. In one embodiment, after determining that a
regeneration process is needed to regenerate particulate filter 95,
controller 80 may determine, based on at least one of the load
measured by load sensor 125, the temperature measured by
temperature sensor 130, and the pressure measured by pressure
sensor 135, the amount of the additive to be injected by additive
injector 70 and the timing to inject the additive.
[0034] For example, controller 80 may determine the amount and
timing of the injection of the additive based on the load measured
by the load sensor 125. After controller 80 receives the signal
generated by load sensor 125, and determines that a regeneration is
needed, controller 80 may activate additive injector 70 and pump 65
to inject a predetermined amount of additive into the fuel flow
supplied to power source 20.
[0035] For another example, when controller 80 receives the
temperature signal generated by temperature sensor 130, and
determines that the temperature of the exhaust or particulate
filter 95 has reached a predetermined temperature threshold,
controller 80 may activate pump 65 and/or additive injector 70 to
inject a predetermine amount of additive into the fuel flow
supplied to power source 20.
[0036] For another example, when controller 80 receives the signal
generated by pressure sensor 135 and determines that the pressure
of the exhaust has exceeded a predetermined threshold, controller
80 may activate pump 65 and/or additive injector 70 to inject a
predetermined amount of additive into the fuel flow supplied to
power source 20. When additive is injected, controller 80 may
control additive injector 70 to inject the additive continuously
for a predetermined amount of time, or to inject a predetermined
amount of additive for a predetermined time interval, for example,
30 seconds. The injection of the additive may be terminated by
controller 80 when regeneration is terminated, or at any desired
suitable time. For example, controller 80 may determine when to
terminate the injection of the additive based on at least one of
the pressure measured by pressure sensor 135, temperature measured
by temperature sensor 130, and load measured by load sensor
125.
[0037] During a regeneration of particulate filter 95, controller
80 may control the combustion within combustion chambers 25 and/or
a fuel-fired burner (not shown) or a heating device (not shown)
associated with particulate filter 95 to increase the temperature
of the exhaust and/or the particulate matter captured by filter
substrate 105 in order to oxidize the particulate matter. As the
temperature is increased to an oxidization temperature range, for
example, 500-600.degree. C., the particulate matter may become
oxidized. At filter substrate 105, the additive may undergo a
chemical reaction, which may catalyze oxidization of the
particulate matter. For example, iron-based additive may lower the
ignition or oxidization threshold temperature of the particulate
matter, thereby enabling oxidization of the particulate matter at a
relatively low temperature, and thus, facilitating the regeneration
of particulate filter 95.
[0038] In some embodiments, because the additive may lower the
temperature required to oxidize or ignite the particulate matter,
the effort required to increase the temperature of the exhaust or
the temperature associated with particulate filter 95 through
intentionally controlling combustion in power source 20, or through
operating a fuel-fired burner, or by controlling a heating device
may be significantly reduced.
[0039] A regeneration process may last for a predetermined period
of time, for example, 10 minutes. During the regeneration process,
particulate matter accumulated on filter substrate 105 may be
burned off from the surfaces of filter substrate 105. Because of
the expelling force existing between the charged exhaust including
particulate matter and/or additives, the particulate matter may be
more uniformly distributed on the surfaces of filter substrate 105.
As a result, during the regeneration process, the particulate
matter accumulated on the surfaces of filter substrate 105 may be
uniformly burned. After the particulate matter is burned, at least
some additive particles may be separated from the surfaces of
filter substrate 105, and may be stored in housing 100. The
additive particles may later be collected for disposal or
recycling, for example, during regular maintenance of particulate
filter 95.
[0040] It will be apparent to those skilled in the art that various
modifications and variations can be made to the power system of the
present disclosure without departing from the scope of the
disclosure. Other embodiments will be apparent to those skilled in
the art from consideration of the specification and practice of the
system disclosed herein. It is intended that the specification and
examples be considered as exemplary only, with a true scope of the
disclosure being indicated by the following claims and their
equivalents.
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