U.S. patent application number 13/273455 was filed with the patent office on 2013-04-18 for monitor of ammonia in dosing system.
This patent application is currently assigned to International Truck Intellectual Property Company, LLC. The applicant listed for this patent is Mark Christen Bach, James C. Bradley, Anthony J. Cook, Lev A. Datskovskiy. Invention is credited to Mark Christen Bach, James C. Bradley, Anthony J. Cook, Lev A. Datskovskiy.
Application Number | 20130091827 13/273455 |
Document ID | / |
Family ID | 47990823 |
Filed Date | 2013-04-18 |
United States Patent
Application |
20130091827 |
Kind Code |
A1 |
Bradley; James C. ; et
al. |
April 18, 2013 |
MONITOR OF AMMONIA IN DOSING SYSTEM
Abstract
An ammonia dosing system has a canister whose interior contains
ammonia luminophores and a delivery apparatus for delivering
ammonia from the canister interior into an exhaust after-treatment
system to entrain with engine exhaust flowing toward an SCR
catalyst for catalytic conversion of NO.sub.x in engine
exhaust.
Inventors: |
Bradley; James C.; (New
Haven, IN) ; Cook; Anthony J.; (Fort Wayne, IN)
; Datskovskiy; Lev A.; (Huntertown, IN) ; Bach;
Mark Christen; (Elk Grove Village, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bradley; James C.
Cook; Anthony J.
Datskovskiy; Lev A.
Bach; Mark Christen |
New Haven
Fort Wayne
Huntertown
Elk Grove Village |
IN
IN
IN
IL |
US
US
US
US |
|
|
Assignee: |
International Truck Intellectual
Property Company, LLC
Warrenville
IL
|
Family ID: |
47990823 |
Appl. No.: |
13/273455 |
Filed: |
October 14, 2011 |
Current U.S.
Class: |
60/274 ;
60/287 |
Current CPC
Class: |
F01N 2900/1806 20130101;
F01N 3/208 20130101; F01N 2560/021 20130101; F01N 2900/18 20130101;
F01N 2610/02 20130101; F01N 2610/148 20130101; F01N 2610/12
20130101; F01N 2610/10 20130101; G01N 21/76 20130101; F01N 2560/02
20130101; F01N 2560/12 20130101 |
Class at
Publication: |
60/274 ;
60/287 |
International
Class: |
F01N 3/10 20060101
F01N003/10; F01N 9/00 20060101 F01N009/00 |
Claims
1. An internal combustion engine comprising: an exhaust
after-treatment system comprising an SCR catalyst; an ammonia
dosing system comprising a canister having an interior containing
ammonia luminophores and a delivery apparatus for delivering
ammonia from the canister interior into the exhaust after-treatment
system to entrain with engine exhaust flowing toward the SCR
catalyst for catalytic conversion of NO.sub.x in the engine
exhaust.
2. The internal combustion engine set forth in claim 1 including a
monitor of ammonia luminophores comprising at least one optical
sensor for detecting luminescence of ammonia luminophores in the
ammonia dosing system.
3. The internal combustion engine set forth in claim 2 in which the
monitor comprises a device providing a signal distinguishing high
luminescence of ammonia luminophores detected by the at least one
optical sensor and low luminescence of ammonia luminophores
detected by the at least one optical sensor.
4. The internal combustion engine set forth in claim 2 in which the
at least one optical sensor provides a measure of luminescence of
ammonia luminophores which the at least one optical sensor detects,
and the monitor converts a measure of luminescence of ammonia
luminophores which the at least one optical sensor detects into a
quantitative measure of ammonia.
5. The internal combustion engine set forth in claim 4 in which the
monitor provides a signal alert when a quantified measure of
ammonia is less than a predetermined quantity.
6. The internal combustion engine set forth in claim 2 in which the
canister comprises a port via which the canister separably connects
to the delivery apparatus, and the at least one optical sensor is
arranged to view luminescence of ammonia luminophores within the
canister's interior.
7. The internal combustion engine set forth in claim 6 including a
closure which, when the canister's port is connected to the
delivery apparatus and the at least one optical sensor detects
luminescence of ammonia luminophores greater than a predetermined
luminescence, allows ammonia flow between the canister interior and
the exhaust after-treatment system, and which, when the canister's
port is connected to the delivery apparatus and the at least one
optical sensor detects luminescence of ammonia luminophores less
than the predetermined luminescence, disallows ammonia flow between
the canister interior and the exhaust after-treatment system.
8. The internal combustion engine set forth in claim 7 in which the
closure and the at least one optical sensor are mounted on the
delivery apparatus.
9. A method for detection of ammonia in an ammonia dosing system
which delivers ammonia into an engine exhaust after-treatment
system to entrain with exhaust flowing toward an SCR catalyst for
catalytic conversion of NO.sub.R, the method comprising: installing
in the ammonia dosing system an ammonia storage canister which
contains ammonia luminophores; operating the ammonia dosing system
to deliver ammonia from the ammonia storage canister into the
exhaust after-treatment system; and using at least one optical
sensor to detect luminescence of ammonia luminophores in the
ammonia dosing system.
10. The method set forth in claim 9 comprising providing a signal
distinguishing high luminescence of ammonia luminophores detected
by the at least one optical sensor and low luminescence of ammonia
luminophores detected by the at least one optical sensor.
11. The method set forth in claim 9 comprising using a measure of
luminescence of ammonia luminophores which the at least one optical
sensor detects to quantify a measure of ammonia.
12. The method set forth in claim 11 including providing a signal
alert when a quantified measure of ammonia is less than a
predetermined quantity.
13. The method set forth in claim 9 comprising arranging the at
least one optical sensor to view luminescence of ammonia
luminophores in the canister's interior and when the at least one
optical sensor detects luminescence of ammonia luminophores greater
than a predetermined luminescence, allowing ammonia flow between
the canister interior and the exhaust after-treatment system, and
when the at least one optical sensor detects luminescence of
ammonia luminophores less than the predetermined luminescence,
disallowing ammonia flow between the canister interior and the
exhaust after-treatment system.
Description
TECHNICAL FIELD
[0001] This disclosure relates to an ammonia dosing system which
delivers ammonia in gas phase from an ammonia storage canister into
exhaust for after-treatment of oxides of nitrogen (NO.sub.x) in the
exhaust by selective catalytic reduction (SCR).
BACKGROUND
[0002] Selective catalytic reduction (SCR) is an exhaust
after-treatment technology for enabling certain chemical reactions
to occur between oxides of nitrogen (NO.sub.x) in exhaust and
ammonia (NH.sub.3) introduced in gas phase into an exhaust system
upstream of an SCR catalyst to entrain with exhaust flowing toward
the catalyst where catalytic reactions convert NO.sub.x into
Nitrogen (N.sub.2) and water (H.sub.2O).
[0003] A motor vehicle which uses SCR technology for
after-treatment of engine exhaust produced by operation of an
internal combustion engine carries an on-board supply of ammonia
which is stored in one or more canisters. Such canisters are
constructed to be removable from a vehicle, re-chargeable at a
service facility, and re-installable in a vehicle.
[0004] Strontium chloride is an example of a storage medium which
is present inside a canister for storing ammonia in solid phase and
releasing stored ammonia in gas phase when heated to an ammonia
release temperature.
[0005] Because selective catalytic reduction of NO.sub.x cannot
occur in the absence of ammonia, information about ammonia in an
ammonia dosing system would be useful in avoiding potential loss or
interruption of ammonia flow between an ammonia storage canister
and in an exhaust system.
SUMMARY OF THE DISCLOSURE
[0006] This disclosure introduces apparatus and method for
acquiring information about ammonia in an ammonia dosing system
through the use of optically detectable ammonia.
[0007] Certain gases which are typically considered not optically
detectable can be made optically detectable by certain processes. A
process which creates what are called "fluorophore absorber pairs"
in an ammonia molecule can render ammonia optically detectable. The
fluorophore absorber pairs radiate absorbed energy at a
characteristic wavelength.
[0008] A gas which has been rendered optically detectable may be
said to luminesce or fluoresce. Although the terms "luminophore"
and "fluorophore" are used in scientific literature as descriptors
of molecules which are optically detectable, it appears that the
latter is used to characterize certain species of the former. The
process which creates fluorophore absorber pairs in an ammonia
molecule suggests that the molecule is a fluorophore, a species of
the generic descriptor "luminophore." The present applicants will
use the term "luminophore" here as a generic descriptor of an
optically detectable molecule.
[0009] The apparatus and method disclosed here are useful in an
ammonia dosing system which treats engine exhaust passing through
an SCR after-treatment system using ammonia which contains ammonia
luminophores.
[0010] The presence of ammonia luminophores in an ammonia dosing
system provides luminescence of ammonia which renders the ammonia
detectable by optical sensing apparatus.
[0011] Specific sensing capabilities of optical sensing apparatus
are a function of specific optical sensing technique employed and
can extend from merely distinguishing between the presence and the
absence of ammonia to measuring ammonia quantity and/or ammonia
flow.
[0012] Several embodiments of apparatus are disclosed.
[0013] The apparatus and method can reduce the likelihood that an
ammonia storage canister which contains little or no ammonia being
installed in a vehicle.
[0014] The apparatus and method can indicate quantity of ammonia
present inside an ammonia storage canister.
[0015] The apparatus and method can indicate outflow of ammonia
from an ammonia storage canister.
[0016] A general aspect of the disclosed subject matter relates to
an internal combustion engine comprising an exhaust after-treatment
system comprising an SCR catalyst, and an ammonia dosing system
comprising a canister having an interior containing optically
detectable ammonia and a delivery apparatus for delivering
optically detectable ammonia from the canister interior into the
exhaust after-treatment system to entrain with engine exhaust
flowing toward the SCR catalyst for catalytic conversion of
NO.sub.x in the engine exhaust.
[0017] A monitor of ammonia luminophores comprises at least one
optical sensor for detecting luminescence of ammonia luminophores
in the ammonia dosing system.
[0018] The monitor comprises a device providing a signal
distinguishing high luminescence of ammonia luminophores detected
by the at least one optical sensor and low luminescence of ammonia
luminophores detected by the at least one optical sensor.
[0019] The least one optical sensor provides a measure of
luminescence of ammonia luminophores which the at least one optical
sensor detects, and the monitor converts a measure of luminescence
of ammonia luminophores which the at least one optical sensor
detects into a quantified measure of ammonia.
[0020] The monitor provides a signal alert when a quantified
measure of ammonia is less than a predetermined quantity.
[0021] The canister comprises a port via which the canister
separably connects to the delivery apparatus, and the at least one
optical sensor is arranged to view luminescence of ammonia
luminophores within the canister's interior.
[0022] When the canister's port is connected to the delivery
apparatus and the at least one optical sensor detects luminescence
of ammonia luminophores greater than a predetermined luminescence,
a closure is operated to allow ammonia flow between the canister
interior and the exhaust after-treatment system. When the
canister's port is connected to the delivery apparatus and the at
least one optical sensor detects luminescence of ammonia
luminophores less than the predetermined luminescence, the closure
is operated to disallow ammonia flow between the canister interior
and the exhaust after-treatment system.
[0023] In a disclosed embodiment, the closure and the at least one
optical sensor are mounted on the delivery apparatus.
[0024] Another general aspect of the disclosed subject matter
relates to a method for detection of ammonia in an ammonia dosing
system which delivers ammonia into an engine exhaust
after-treatment system to entrain with exhaust flowing toward an
SCR catalyst for catalytic conversion of NO.sub.x. The method
comprises: installing in the ammonia dosing system an ammonia
storage canister which contains ammonia luminophores; operating the
ammonia dosing system to deliver ammonia from the ammonia storage
canister into the exhaust after-treatment system; and using at
least one optical sensor to detect luminescence of ammonia
luminophores in the ammonia dosing system.
[0025] The method comprises providing a signal distinguishing high
luminescence of ammonia luminophores detected by the at least one
optical sensor and low luminescence of ammonia luminophores
detected by the at least one optical sensor.
[0026] The method comprises using a measure of luminescence of
ammonia luminophores which the at least one optical sensor detects
to quantify a measure of ammonia.
[0027] The method provides a signal alert when a quantified measure
of ammonia is less than a predetermined quantity.
[0028] The method comprises arranging the at least one optical
sensor to view luminescence of ammonia luminophores in the
canister's interior and when the at least one optical sensor
detects luminescence of ammonia luminophores greater than a
predetermined luminescence, allowing ammonia flow between the
canister interior and the exhaust after-treatment system, and when
the at least one optical sensor detects luminescence of ammonia
luminophores less than the predetermined luminescence, disallowing
ammonia flow between the canister interior and the exhaust
after-treatment system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a general schematic diagram of an internal
combustion engine which utilizes SCR to convert NO.sub.x in engine
exhaust by chemical reaction with ammonia introduced into the
exhaust.
[0030] FIG. 2 is a schematic diagram showing more detail.
[0031] FIG. 3 is a schematic diagram similar to FIG. 2 but showing
a different embodiment.
DETAILED DESCRIPTION
[0032] FIG. 1 shows a representative internal combustion engine 10
which can be used in stationary or mobile applications. For
example, engine 10 may be a diesel engine of the type which propels
a motor vehicle such as a truck and which comprises structure
forming a number of engine cylinders 12 into which fuel is injected
by fuel injectors 14 to combust with air which has entered
combustion chamber spaces of engine cylinders 12 through an intake
system 16 when cylinder intake valves 18 for controlling admission
of air from an intake manifold 20 into respective engine cylinders
12 are open.
[0033] Engine 10 also comprises an exhaust system 22 through which
engine exhaust created by combustion of injected fuel in the
combustion chamber spaces to operate engine 10 is conveyed to
atmosphere. Cylinder exhaust valves 24 control admission of exhaust
from respective engine cylinders 12 into an exhaust manifold 26 for
further conveyance through exhaust system 22.
[0034] Exhaust system 22 includes an exhaust after-treatment system
28, including an SCR catalyst 30 for treating exhaust passing
through after-treatment system 28 prior to entry into the
atmosphere. An ammonia dosing system 32 provides ammonia in gas
phase for catalytic conversion of NO.sub.x in the exhaust.
[0035] Ammonia dosing system 32 comprises at least one ammonia
storage canister 34 and an ammonia dosing controller 36 for
controlling delivery of ammonia through an ammonia delivery
apparatus 38 into after-treatment system 28 and for monitoring
ammonia in the ammonia dosing system.
[0036] FIG. 2 shows one of the storage canisters 34 to comprise a
walled enclosure 40 having a port 42 at one axial end via which the
canister separably connects to ammonia delivery apparatus 38.
[0037] Ammonia delivery apparatus 38 comprises a tubular conduit
terminating is a fitting 44 to which port 42 separably connects.
Fitting 44 contains at least one optical sensor 46 and a
selectively positionable closure 48.
[0038] Canister 34 comprises an interior containing an ammonia
storage medium 50 for storing ammonia in solid phase and releasing
stored ammonia in gas phase when heated to an ammonia release
temperature. The stored ammonia comprises ammonia luminophores in
quantity sufficient to provide for detection by at least one
optical sensor 46 even when ammonia remaining in canister 34
reaches a point calling for canister replacement. FIG. 2 shows at
least one optical sensor 46 arranged to view luminescence of
optically detectable ammonia within the canister's interior.
[0039] The at least one sensor 46 and any associated device or
devices, such as a device 52, form a monitor 54 of ammonia
luminophores. Specific sensing capabilities of a particular monitor
54 are a function of specific optical sensing technique employed. A
monitor may have a capability extending beyond merely detecting the
presence or absence of ammonia to a capability of measuring ammonia
quantity and/or ammonia flow.
[0040] Device 52 functions to provide a signal distinguishing high
luminescence of ammonia luminophores detected by the at least one
optical sensor 46 and low luminescence of ammonia luminophores
detected by the at least one optical sensor 46. Low luminescence
includes no luminescence.
[0041] At least one sensor 46 which provides a measure of
luminescence of ammonia luminophores which the at least one optical
sensor 46 detects can enable monitor 54 to convert a measure of
luminescence of ammonia luminophores which the at least one optical
sensor 46 detects into a quantified measure of ammonia in canister
34.
[0042] Monitor 54 can provide a signal alert when a quantified
measure of ammonia is less than a predetermined quantity. This is
useful in signaling that ammonia in a canister presently in use is
approaching depletion and that a fresh canister should be brought
on line.
[0043] When port 42 is connected to fitting 44 so that at least one
optical sensor 46 can detect luminescence of ammonia luminophores
within the canister interior, and the detected luminescence is
greater than a predetermined luminescence, ammonia dosing
controller 36 positions closure 48 via an actuator (not shown) to
allow ammonia flow between the canister interior and
after-treatment system 28. When port 42 is connected to fitting 44
and at least one optical sensor 46 detects luminescence of ammonia
luminophores less than the predetermined luminescence, ammonia
dosing controller 36 positions closure 48 to disallow ammonia flow
between the canister interior and the after-treatment system.
[0044] Because of the presence of at least one optical sensor 46
and closure 48 in association with ammonia dosing controller 36,
the presence of ammonia in a newly installed canister will be
verified by at least one sensor 46 detecting luminescence of
ammonia luminophores within the interior of the canister and
consequently ammonia dosing controller 36 operating closure 48 to
allow flow. If the presence of ammonia in a newly installed
canister is not verified, ammonia dosing controller 36 maintains
closure 48 in the same closed position which it had assumed when
the previous canister was disconnected from fitting 44 to disallow
flow.
[0045] The embodiment of FIG. 3 differs from that of FIG. 2 in that
the at least one sensor 46 and closure 48 are mounted on canister
port 42 rather than on fitting 44. Both the least one sensor 46 and
the actuator for operating closure 48 are to be connected to device
52 and ammonia dosing controller 36 as shown after port 42 has been
connected to fitting 44.
* * * * *