US2014123629A1PendingUtilityA1
Ammonia slip detection
Assignee: INT ENGINE INTELLECTUAL PROPPriority: Nov 2, 2012Filed: Jul 16, 2013Published: May 8, 2014
Est. expiryNov 2, 2032(~6.3 yrs left)· nominal 20-yr term from priority
F01N 2560/14F01N 2900/1616Y02T10/12F01N 2900/1402F01N 11/00F01N 2900/1621B01D 53/9495Y02T10/40F01N 3/2066F01N 2900/08B01D 2251/2062F01N 2560/026B01D 53/9409F01N 2550/02F01N 3/208
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Claims
Abstract
A method of detecting ammonia in the exhaust system includes detecting a predetermined engine operating condition. Upon detecting the predetermined operating condition, the method determines a first NO x conversion efficiency of a catalyst at a first time T 1. The method then injects a reactant into the exhaust upstream of the catalyst and determines a second NO x conversion efficiency at a second time T 2. The method then processes the first and second NO x conversion efficiencies to determine whether an ammonia slip condition exists.
Claims
exact text as granted — not AI-modified1 . A method of detecting ammonia slip across a catalyst in an exhaust system of an internal combustion engine comprising;
detecting a preselected operating condition of the engine; determining a first NO x conversion efficiency of the catalyst at a first time; injecting a reductant into the exhaust upstream of the catalyst; thereafter detecting a second NO x conversion efficiency of the catalyst at a second time; and processing the first and second NO x conversion efficiencies to determine whether an ammonia slip condition exists.
2 . The method of claim 1 , wherein the reductant comprises ammonia.
3 . The method of claim 1 , wherein the preselected engine operating condition comprises a steady state condition.
4 . The method of claim 1 , wherein the step of determining a first NO x conversion efficiency of the catalyst at a first time further comprises:
detecting a first upstream NO x level relative to the catalyst at the first time; and detecting a first downstream NO x level relative to the catalyst at the first time.
5 . The method of claim 1 , wherein the step of determining a second NO x conversion efficiency of the catalyst at a second time further comprises:
detecting a second upstream NO x level relative to the catalyst at the second time; and detecting a second downstream NO x level relative to the catalyst at the second time.
6 . The method of claim 1 , wherein NO x conversion efficiency is determined in accordance with the following formula:
Eff
=
NO
x
-
upstream
-
NO
x
-
downstream
NO
x
-
upstream
·
100
where Eff is NO x conversion efficiency, NO x-upstream is the upstream NO x level and NO x-downstream is the downstream NO x level.
7 . The method of claim 1 , further comprising signaling an ammonia slip condition in response to the NO x conversion efficiency increasing between the first and second times.
8 . A method of detecting ammonia slip across a catalyst in an exhaust system of an internal combustion engine comprising:
detecting a preselected operating condition of the engine; thereafter detecting a first upstream NO x level relative to the catalyst at a first time; detecting a first downstream NO x level relative to the catalyst at a first time; injecting a reductant into the exhaust upstream of the catalyst; thereafter detecting a second upstream NO x level relative to the catalyst at a second time; detecting a second downstream NO x level relative to the catalyst at a second time; and determining a first NO x conversion efficiency based on the first upstream and first downstream NO x levels; determining second NO x conversion efficiency based on the second upstream and second downstream NO x levels; and processing the first and second NO x conversion efficiencies to determine whether an ammonia slip condition exists.
9 . The method of claim 8 , wherein NO x conversion efficiency is determined in accordance with the following formula:
Eff
=
NO
x
-
upstream
-
NO
x
-
downstream
NO
x
-
upstream
·
100
where Eff is NO x conversion efficiency, NO x-upstream is the upstream NO x level and NO x-downstream is the downstream NO x level.
10 . The method of claim 9 , wherein the reductant comprises ammonia.
11 . The method of claim 10 , wherein the preselected engine operating condition comprises a steady state condition.
12 . A system for detecting ammonia in an exhaust system of an internal combustion engine, the exhaust system including a catalyst and an injector upstream of the catalyst for injecting a reductant into the exhaust system, the system comprising:
an upstream NO x sensor positioned to detect the level of NO x in the exhaust stream at a location upstream of the catalyst and produce a responsive upstream NO x signal; a downstream NO x sensor positioned to detect the level of NO x in the exhaust stream at a location downstream of the catalyst and produce a responsive downstream NO x signal; a controller configured to receive the upstream and downstream NO x signals; detect a preselected engine operating condition; determine a first NO x conversion efficiency based on the upstream and downstream NO x levels at a first time; signal the injector to inject reductant into the exhaust system; determine a second NO x conversion efficiency based on the upstream and downstream NO x levels at a second time following injection of the reluctant; and process the first and second NO x conversion efficiencies to determine whether an ammonia slip condition exists.
13 . The system of claim 12 , wherein the preselected engine operating condition comprises a steady state operating condition.
14 . The method of claim 12 , wherein NO x conversion efficiency is determined in accordance with the following formula:
Eff
=
NO
x
-
upstream
-
NO
x
-
downstream
NO
x
-
upstream
·
100
where Eff is NO x conversion efficiency, NO x-upstream is the upstream NO x level and NO x-downstream is the downstream NO x level.
15 . The method of claim 12 , wherein the reductant comprises ammonia.Join the waitlist — get patent alerts
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