U.S. patent application number 11/335135 was filed with the patent office on 2007-07-19 for reagent refill and supply system for an scr exhaust aftertreatment system.
Invention is credited to Rod Radovanovic, Todd A. Sheridan, Laszlo D. Tikk.
Application Number | 20070163245 11/335135 |
Document ID | / |
Family ID | 38261830 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070163245 |
Kind Code |
A1 |
Sheridan; Todd A. ; et
al. |
July 19, 2007 |
Reagent refill and supply system for an SCR exhaust aftertreatment
system
Abstract
An internal combustion engine includes an exhaust manifold, and
a selective catalytic reduction exhaust aftertreatment system. The
selective catalytic reduction exhaust aftertreatment system
includes a reduction catalytic converter in communication with the
exhaust manifold; a reagent holding tank in fluid communication
with the reduction catalytic converter; and a reagent supply
canister selectively and removably couplable with the reagent
holding tank.
Inventors: |
Sheridan; Todd A.;
(Fortville, IN) ; Tikk; Laszlo D.; (Columbus,
IN) ; Radovanovic; Rod; (Columbus, IN) |
Correspondence
Address: |
SAWYER LAW GROUP LLP
P O BOX 51418
PALO ALTO
CA
94303
US
|
Family ID: |
38261830 |
Appl. No.: |
11/335135 |
Filed: |
January 19, 2006 |
Current U.S.
Class: |
60/286 ; 60/295;
60/301 |
Current CPC
Class: |
F01N 2610/1406 20130101;
Y02T 10/24 20130101; F01N 3/2066 20130101; F01N 2610/14 20130101;
Y02T 10/12 20130101; F01N 2610/10 20130101; F01N 2610/02
20130101 |
Class at
Publication: |
060/286 ;
060/295; 060/301 |
International
Class: |
F01N 3/00 20060101
F01N003/00; F01N 3/10 20060101 F01N003/10 |
Claims
1. An internal combustion engine, comprising: an exhaust manifold;
and a selective catalytic reduction exhaust aftertreatment system,
including: a reduction catalytic converter in communication with
said exhaust manifold; a reagent holding tank in fluid
communication with said reduction catalytic converter; and a
reagent supply canister selectively and removably couplable with
said reagent holding tank.
2. The internal combustion engine of claim 1, wherein said reagent
holding tank includes a refill head with a seal and a latch.
3. The internal combustion engine of claim 2, wherein said seal
comprises an O-ring seal.
4. The internal combustion engine of claim 2, wherein said reagent
supply canister includes a nozzle with a spring biased valve and a
mating latch.
5. The internal combustion engine of claim 4, wherein said valve
includes a valve disk biased by a compression spring.
6. The internal combustion engine of claim 5, wherein said refill
head includes a valve opener pin for biasing said valve disk to an
open position when said reagent supply canister is coupled with
said reagent holding tank.
7. The internal combustion engine of claim 4, wherein said latch
comprises a bayonet latch and said mating latch comprises a mating
bayonet latch.
8. The internal combustion engine of claim 1, wherein said reagent
holding tank includes a heater.
9. The internal combustion engine of claim 8, wherein said heater
includes at least one resistance heater.
10. The internal combustion engine of claim 1, wherein said reagent
holding tank includes at least one reagent level sensor.
11. The internal combustion engine of claim 10, further including a
visual indicator coupled with at least one said reagent level
sensor.
12. The internal combustion engine of claim 10, wherein said
reagent holding tank includes two reagent level sensors.
13. The internal combustion engine of claim 1, wherein said reagent
holding tank includes a sump and a suction line having an inlet in
said sump.
14. The internal combustion engine of claim 1, including at least
one of a reagent quality sensor and a NOx sensor.
15. The internal combustion engine of claim 14, wherein said
reagent quality sensor is positioned in said reagent holding
tank.
16. An internal combustion engine, comprising: an exhaust manifold;
and a selective catalytic reduction exhaust aftertreatment system,
including: a reduction catalytic converter in communication with
said exhaust manifold; and a reagent holding tank in communication
with said reduction catalytic converter, said reagent holding tank
including a refill head selectively couplable with a reagent supply
canister, said refill head being substantially sealed with said
reagent supply canister when coupled with said reagent supply
canister, and substantially sealed with an ambient environment when
not coupled with said reagent supply canister.
17. The internal combustion engine of claim 16, wherein said refill
head includes a seal and a latch.
18. The internal combustion engine of claim 17, wherein said seal
comprises an O-ring seal.
19. The internal combustion engine of claim 17, wherein said latch
comprises a bayonet latch.
20. The internal combustion engine of claim 16, wherein said
reagent holding tank includes a heater.
21. The internal combustion engine of claim 20, wherein said heater
includes at least one resistance heater.
22. The internal combustion engine of claim 16, wherein said
reagent holding tank includes at least one reagent level
sensor.
23. The internal combustion engine of claim 22, further including a
visual indicator coupled with at least one said reagent level
sensor.
24. The internal combustion engine of claim 22, wherein said
reagent holding tank includes two reagent level sensors.
25. The internal combustion engine of claim 16, wherein said
reagent holding tank includes a sump and a suction line having an
inlet in said sump.
26. The internal combustion engine of claim 16, including at least
one of a reagent quality sensor and a NOx sensor.
27. The internal combustion engine of claim 26, wherein said
reagent quality sensor is positioned in said reagent holding
tank.
28. An exhaust aftertreatment system for an internal combustion
engine, comprising: a reduction catalytic converter; a reagent
holding tank in communication with said reduction catalytic
converter; and a reagent supply canister selectively and removably
couplable with said reagent holding tank.
29. The exhaust aftertreatment system of claim 28, wherein said
reagent holding tank includes a refill head with a seal and a
latch.
30. The exhaust aftertreatment system of claim 29, wherein said
seal comprises an O-ring seal.
31. The exhaust aftertreatment system of claim 29, wherein said
reagent supply canister includes a nozzle with a spring biased
valve and a mating latch.
32. The exhaust aftertreatment system of claim 31, wherein said
valve includes a valve disk biased by a compression spring.
33. The exhaust aftertreatment system of claim 32, wherein said
refill head includes a valve opener pin for biasing said valve disk
to an open position when said reagent supply canister is coupled
with said reagent holding tank.
34. The exhaust aftertreatment system of claim 31, wherein said
latch comprises a bayonet latch and said mating latch comprises a
mating bayonet latch.
35. The exhaust aftertreatment system of claim 28, wherein said
reagent holding tank includes a heater.
36. The exhaust aftertreatment system of claim 35, wherein said
heater includes at least one resistance heater.
37. The exhaust aftertreatment system of claim 28, wherein said
reagent holding tank includes at least one reagent level
sensor.
38. The exhaust aftertreatment system of claim 37, further
including a visual indicator coupled with at least one said reagent
level sensor.
39. The exhaust aftertreatment system of claim 37, wherein said
reagent holding tank includes two reagent level sensors.
40. The exhaust aftertreatment system of claim 28, wherein said
reagent holding tank includes a sump and a suction line having an
inlet in said sump.
41. The exhaust aftertreatment system of claim 28, including at
least one of a reagent quality sensor and a NOx sensor.
42. The internal combustion engine of claim 41, wherein said
reagent quality sensor is positioned in said reagent holding
tank.
43. A method of operating an internal combustion engine, comprising
the steps of: treating exhaust gas with a selective catalytic
reduction system including a reduction catalytic converter;
supplying a reagent to said reduction catalytic converter from a
reagent holding tank; coupling a reagent supply canister with a
refill head on said reagent holding tank; and refilling said
reagent holding tank with reagent from said reagent supply
canister.
44. The method of operating an internal combustion engine of claim
43, including the step of removing said reagent supply canister
from said refill head.
45. The method of operating an internal combustion engine of claim
43, wherein said coupling step includes sealing and latching said
reagent supply canister with said reagent holding tank.
46. The method of operating an internal combustion engine of claim
43, including the step of opening a valve in said reagent supply
canister, thereby allowing said refilling step.
47. The method of operating an internal combustion engine of claim
46, wherein said opening step occurs concurrently with said
coupling step.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to exhaust aftertreatment
systems for use in internal combustion engines, and, more
particularly, to such exhaust aftertreatment systems using
selective catalytic reduction.
[0003] 2. Description of the Related Art
[0004] Increasingly stringent emissions control standards
necessitate continually improved emissions from internal combustion
(IC) engines used as motive power for vehicles. At present, the
most significant of these emissions are sulfur dioxide (SO.sub.2),
oxides of nitrogen (NOx), and airborne particulate.
[0005] NOx refers to the cumulative emissions of nitric oxide (NO),
nitrogen dioxide (NO.sub.2) and trace quantities of other species
generated during combustion. NOx emissions are minimized using low
NOx combustion technology and postcombustion techniques. If
combustion modifications alone are insufficient, postcombustion
techniques such as selective catalytic reduction (SCR) systems may
be employed. In SCR systems, NOx is reduced to nitrogen (N.sub.2)
and water (H.sub.2O) through a series of reactions with a chemical
reactive agent (reagent) injected into the exhaust gas. Ammonia and
urea are the most commonly used chemical reagents with SCR
systems.
[0006] In 2007, it is estimated that engine out NOx emissions will
on average be approximately 1.2 g/hp-hr (gallons/horse power-hour).
In order to meet the 2010 NOx standard of 0.2 g/hp-hr, an SCR
system (using ammonia) can be used. For about 1 g/hp-hr NOx
reduction the amount of ammonia (NH.sub.3) required is not very
large. Since anhydrous ammonia is a toxic substance, another likely
reagent is an aqueous solution of 32.5% urea and 67.5% water,
although the exact reagent formulation can vary from one
application to another. To achieve the desired 1 g/hp-hr NOx
reduction, the amount of the proposed reagent required is
approximately 1.3% of the diesel fuel burned, on average.
[0007] Since the urea mixture is a depletable supply, one
contemplated supply solution is to provide a bulk tank at fueling
stations with a supply hose and nozzle used for refilling a holding
tank on the vehicle. This urea mixture supply solution may have
logistics difficulties, however, with inadvertent spillage from the
nozzle, the need to dedicate or retrofit a supply hose and nozzle
at each fueling island, etc.
[0008] What is needed in the art is a quick, convenient and
relatively safe system and method for refilling a reagent for use
in an SCR exhaust aftertreatment system.
SUMMARY OF THE INVENTION
[0009] The present invention provides a reagent refill and supply
system and method including a reagent holding tank permanently
onboard the vehicle, and a portable and selectively couplable
reagent supply canister for refilling the reagent holding tank.
[0010] The invention comprises, in one form thereof, an internal
combustion engine including an exhaust manifold; and a selective
catalytic reduction exhaust aftertreatment system. The selective
catalytic reduction exhaust aftertreatment system includes a
reduction catalytic converter in communication with the exhaust
manifold; a reagent holding tank in fluid communication with the
reduction catalytic converter; and a reagent supply canister
selectively and removably couplable with the reagent holding
tank.
[0011] The invention comprises, in another form thereof, a method
of operating an internal combustion engine, including the steps of:
treating exhaust gas with a selective catalytic reduction system
including a reduction catalytic converter; supplying a reagent to
the reduction catalytic converter from a reagent holding tank;
coupling a reagent supply canister with a refill head on the
reagent holding tank; and refilling the reagent holding tank with
reagent from the reagent supply canister.
[0012] An advantage of the present invention is that the reagent
can be quickly and easily replenished in a motor vehicle at
periodic intervals as it is depleted from the reagent holding
tank.
[0013] Another advantage is that the periodic interval can be a
predetermined interval or can be a varying interval based upon a
sensed reagent level in the holding tank.
[0014] Yet another advantage is that the reagent supply canister is
sealed to the ambient environment and automatically opened upon
coupling with the reagent holding tank to allow reagent
refilling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0016] FIG. 1 is a schematic illustration of an internal combustion
engine including an embodiment of a reagent refill and supply
system of the present invention;
[0017] FIG. 2 is a plan view of the reagent refill and supply
system shown in FIG. 1, with the reagent supply canister removed
from the reagent holding tank;
[0018] FIG. 3 is a plan view of the reagent refill and supply
system shown in FIGS. 1 and 2, with the reagent supply canister
coupled with the reagent holding tank;
[0019] FIG. 4 is a plan view of another embodiment of a reagent
refill and supply system of the present invention, with one reagent
supply canister coupled with the reagent holding tank, and a
reserve reagent supply canister carried in a standby position.
[0020] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate one preferred embodiment of the invention, in one
form, and such exemplifications are not to be construed as limiting
the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Referring now to the drawings, and more particularly to FIG.
1, there is shown an IC engine 10 including an embodiment of an SCR
exhaust aftertreatment 12. In the embodiment shown, IC engine 10 is
a diesel engine including a cylinder block 14 defining a plurality
of combustion cylinders 16, an intake manifold 18, an exhaust
manifold 20 and a turbocharger 22.
[0022] Cylinder block 14 is shown as including six combustion
cylinders, but may also include a different number of combustion
cylinders, such as eight, ten or twelve combustion cylinders.
[0023] Intake manifold 18 and exhaust manifold 20 are each in fluid
communication with the plurality of combustion cylinders 16, and
may be of single part design, as shown, or of multiple part
design.
[0024] Exhaust manifold 20 discharges exhaust gas to turbine 24 of
turbocharger 22. Turbine 24 may be of a fixed geometry as shown, or
may be an adjustable turbine such as a variable geometry turbine
(VGT). Exhaust gas from exhaust manifold 20 rotatably drives
turbine 24, and is then discharged to SCR exhaust aftertreatment
system 12, as will be described in more detail hereinafter.
[0025] Turbine 24 rotatably drives compressor 26 via a shaft 28, as
indicated by arrow 30. Compressor 26 receives air from the ambient
environment, compresses the air and provides compressed charge air
to intake manifold 18.
[0026] SCR exhaust aftertreatment system 12 generally includes a
reduction catalytic converter 32, doser 34, reagent holding tank 36
and reagent supply canister 38. Reduction catalytic converter 32
may be of conventional design for an SCR exhaust aftertreatment
system. Doser 34 provides a predetermined amount of reagent which
is mixed with the exhaust gas discharged from turbine 24. The
reagent is preferably mixed with the exhaust gas upstream from
reduction catalytic converter 32 for sufficient mixing prior to
entering reduction catalytic converter 32. Doser 34 may also be of
any suitable configuration, and is thus not discussed further.
[0027] Reagent holding tank 36 and reagent supply canister 38
together define a reagent refill and supply system 40, shown in
more detail in FIGS. 2 and 3. Reagent supply canister 38 is
selectively and removably coupled with reagent holding tank 36 for
selectively filling reagent holding tank 36 at periodic intervals.
Reagent supply canister 38 is shown in an uncoupled position above
reagent holding tank 36 in FIG. 2, and is shown in a coupled
position in FIG. 3.
[0028] Reagent holding tank 36 includes a refill head 42 which is
sized and configured to couple in a sealed manner with reagent
supply canister 38. More particularly, reagent supply canister 38
includes a nozzle 44 having an outside diameter which is slightly
smaller than the inside diameter of refill head 42. Refill head 42
includes an annular groove (not numbered) at the inside diameter
thereof which receives an O-ring seal 46. O-ring seal 46 fluidly
seals between nozzle 44 and refill head 42 when reagent supply
canister 38 is coupled with reagent holding tank 36 (FIG. 3).
[0029] Refill head 42 includes a first latch 48 and nozzle 44
includes a second latch 50 which mate together when reagent supply
canister 38 is coupled with reagent holding tank 36. In the
embodiment shown, latches 48 and 50 are bayonet latches, but may be
differently configured depending upon the application. Latch 48 is
a female-type bayonet latch and latch 50 is a male-type bayonet
latch.
[0030] Positioned within nozzle 44 is a spring biased valve 52
which opens and closes to substantially seal reagent supply
canister 38 from the ambient environment when in a closed position,
and allow transfer of the reagent from reagent supply canister 38
to reagent holding tank 36 when in an open position. In the
embodiment shown, valve 52 is in the form of a valve disk which is
biased to the closed position by a compression spring 54. Valve 52
is shown in the closed position in FIG. 2.
[0031] To bias valve 52 to an open position shown in FIG. 3,
reagent holding tank 36 includes a valve opener pin 56 having a
distal end which is generally centrally positioned within refill
head 42 and extends toward the opening of refill head 42. When
reagent supply canister 38 is coupled with reagent holding tank 36,
valve opener pin 56 opens valve disk 52 by exerting a force against
valve disk 52 and compressing spring 54.
[0032] Reagent holding tank 36 may also include an optional heater
58 therein for heating the reagent during cold weather. In the
embodiment shown, heater 58 is in the form of a single resistance
heater wire configured as a heater coil extending into a sump 60 in
the bottom of reagent holding tank 36. A suction line 62 in
communication with doser 34 has an inlet 64 for receiving reagent
near the bottom of sump 60. Heater 58 receives electrical power at
electrical leads 66 from an on-board power supply (such as one or
more vehicle batteries) through controllable actuation using
onboard controller 68.
[0033] To provide an operator with an indication of the level of
reagent within reagent holding tank 36, one or more reagent level
sensors 70 are positioned at respective heights within reagent
holding tank 36. In the embodiment shown, a pair of reagent level
sensors 70 are in communication with controller 68 via respective
leads 72. Controller 68 receives a signal from one or more reagent
level sensors 70 and provides an output signal to visual indicator
74 providing an operator with a real time indication of the reagent
level within reagent holding tank 36 and/or the need to refill
reagent holding tank 36.
[0034] SCR exhaust aftertreatment system 12 may also optionally
include a reagent quality sensor 76 providing an output signal to
controller 68 indicative of the quality of reagent within reagent
holding tank 36. Additionally, an optional NOx sensor 78 (FIG. 1)
also coupled with controller 68 may be positioned in the exhaust
gas flow downstream from reduction catalytic converter 32.
[0035] Referring now to FIG. 4, another embodiment of a reagent
refill and supply system 80 of the present invention is shown.
Reagent refill and supply system 80 includes a reagent holding tank
82 and a reagent supply canister 84A which are similar in many
respects to reagent holding tank 36 and reagent supply canister 38
shown in FIGS. 1-3. However, reagent holding tank 82 does not
include a sump, includes only a single reagent level sensor 70, and
does not include a bayonet type latch. Rather, a pair of finger
type latches 86 on opposite sides of reagent supply canister 84A
engage the upper surface of an annular ring 88 at the outer
periphery of reagent supply canister 84A. An onboard reserve
canister holder 90 carries a reserve reagent supply canister 84B
which may be used for refilling reagent within reagent holding tank
82. Reserve reagent supply canister 84B is biased in an upward
direction by a compression spring 92, which is compressed to a
greater or lesser extent depending upon the amount of reagent
within reserve agent supply canister 84B. A canister weight sensor
94 coupled with controller 68 provides a signal indicating the
amount of reagent within reserve reagent supply canister 84B. It
may be possible to configure canister weight sensor 94 as a
proximity sensor, inductive sensor or other suitably configured
sensor, depending upon the application.
[0036] Reagent refill and supply system 80 also includes an
optional housing 96 in which reagent holding tank 82, reagent
supply canister 84A and reserve reagent supply canister 84B are
positioned. Of course, it is also possible to enclose reagent
refill and supply system 40 shown in FIGS. 2 and 3 within a
housing.
[0037] During operation, when the level of the urea solution
reaches the upper reagent level sensor 70, a light in the
instrument panel indicates that at the next diesel fueling the urea
solution needs to be replenish with one canister of urea. In the
case that the driver, for some reason, fully refueled the diesel
tank(s) just before the upper reagent level sensor 70 sent the
signal, there is enough urea solution between the upper reagent
level sensor 70 and the lower reagent level sensor 70 for an
uninterrupted trip achievable with full tanks of the diesel fuel.
In the case of 200 gallons of diesel fuel, that would be about 2.6
gallons of urea solution. If for some reason, the driver would
again fail to refill the urea, then during the next trip when the
level of the reagent reaches the lower reagent level sensor 70, a
red light on the instrument panel indicates that the reagent must
be refilled soon. The volume of the urea below the lower reagent
level sensor 70 (approximately 0.4 gallons) is sufficient for
approximately 240 miles of travel. At that time reagent holding
tank 36 must be filled with 6 gallons of urea (two reagent supply
canisters 38).
[0038] During a regular diesel refueling, the operator purchases
one reagent supply canister 38 (or two if required). After an
optional cap (not shown)is removed, reagent supply canister 38 is
placed on refill head 42. O-ring seal 46 engages with nozzle 44,
and after lowering of reagent supply canister 38, bayonet type
latches 48 and 50 are latched together by turning reagent supply
canister 38 through approximately ninety degrees. Valve opener pin
56 pushes valve disk 52 into an open position and reagent flows
from reagent supply canister 38 into reagent holding tank 36. After
several seconds, reagent supply canister 38 empties, is removed,
and the cap is replaced. The empty reagent supply canister 38 is
returned to the fueling station.
[0039] In the event of ambient air below approximately -11.degree.
C., heater 58 may be actuated to heat reagent within reagent
holding tank 36. However, since reagent holding tank 36 is small it
can also be attached to the heated cab sleeper and thus would not
require electricity during the vehicle trip. However, if the
vehicle is parked for an extended period in the sub -11.degree. C.
weather, the urea solution could freeze and therefore a freeze
tolerant tank design and a heater is required. In situations where
the solution freezes during vehicle inactivity, the heating system
within reagent holding tank 36 is activated at the start of the
truck engine. The heating system would be designed such that
adequate urea solution for operation would melt by the time the
exhaust components (mainly catalyst) would reach the operating
temperature.
[0040] If a reagent quality sensor 76 is used (e.g., an aqueous
urea quality sensor), the engine power can be reduced to a limp
home mode if adequate urea solution is not available. This may be
important since a lack of adequate urea solution would result in
tail pipe NOx emissions exceeding the emissions standard. In
addition, optional NOx sensor 78 can be used to reduce engine power
if any of the emissions control devices fail, such as an
insufficient supply of urea in reagent holding tank 36
[0041] While this invention has been described as having a
preferred design, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *