Patent EP0697062B1 successfully refreshed from Google Patents.
EP0697062B1
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EP
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Process and device for controllably adding a reducing agent into nitrogen oxide-containing exhaust gas
Assignee: Johnson Matthey Catalysts Germany GmbH
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Filing: 1994-04-27
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Granted: 1996-09-25
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Expires: 2014-04-27
Abstract
Abstract A method for the controlled introduction of a reducing agent into a nitrogen oxide-containing exhaust gas leaving an internal combustion engine through an exhaust line having a catalytic converter built in for reducing nitrogen oxide, includes detecting at least one operation-relevant parameter of the exhaust gas, of the catalytic converter and optionally of the engine to determine the nitrogen oxide rate. An intermediate value is determined for the reducing agent rate as a function of the nitrogen oxide rate. The intermediate value is reduced by a rate of the reducing agent desorbed by the catalytic converter or raised by a rate of the reducing agent adsorbed by the catalytic converter. An apparatus for performing the method includes a control unit. A device detects at least one operation-relevant parameter of the exhaust gas, of the catalytic converter and optionally of the engine. A reducing agent supply unit introduces the reducing agent into the exhaust line upstream of the catalytic converter. The control unit is intended to adjust a rate of the reducing agent introduced into the exhaust gas as a function of the parameters, while taking into account a rate of the reducing agent adsorbed by the catalytic converter or desorbed by the catalytic converter.
Inventors
- 👤 Helmut Schmelz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 13:55
CPC Classifications
F; F01; F01N; F01N11/00; B; B01; B01D; B01D53/00; B01D53/30; B01D53/34; B01D53/74; B01D53/86; B01D53/8696; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9495; F01N13/00; F01N13/009; F01N13/0097; F01N3/00; F01N3/08; F01N3/10; F01N3/103; F01N3/105; F01N3/106; F01N3/18; F01N3/20; F01N3/206; F01N3/208; F01N13/008; F01N2240/00; F01N2240/40; F01N2390/00; F01N2390/02; F01N2560/00; F01N2560/02; F01N2560/021; F01N2560/026; F01N2560/06; F01N2560/07; F01N2560/08; F01N2570/00; F01N2570/18; F01N2610/00; F01N2610/02; F01N2610/14; F01N2610/1453; F01N2610/146; F01N2900/00; F01N2900/06; F01N2900/08; F02; F02B; F02B3/00; F02B3/06; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
158 words
Method for the controlled introduction of a reducing agent (26) into a nitrogen oxide-containing exhaust gas (10) of an internal combustion engine (4) with a catalytic converter unit (8) installed in the exhaust line (2) for the purpose of lowering the nitrogen oxide content, in which at least one operationally relevant parameter of the exhaust gas (10), at least one operationally relevant parameter of the catalytic converter unit (8) and, if required, at least one operationally relevant parameter of the engine (4) being recorded in order to determine the nitrogen oxide rate Ṁ NO x , characterized in that, in accordance with the nitrogen oxide rate Ṁ NO x , an intermediate value Z 1 ( Ṁ R ) for the reducing-agent rate Ṁ R is determined, which is reduced by a reducing-agent rate Ṁ D desorbed by the catalytic converter unit (8) or increased by a reducing-agent rate Ṁ A adsorbed by the catalytic converter unit (8).
Claim 2
Dependent Claim
55 words
Method according to Claim 1, characterized in that, in a determination of the desorbed reducing-agent rate Ṁ D and the adsorbed reducing-agent rate Ṁ A account is taken of the fact that the specific storage capacity C R for the reducing agent falls as the exhaust-gas temperature rises and increases as the exhaust-gas pressure rises.
Claim 3
Dependent Claim
45 words
Method according to Claim 1 or 2 characterized in that the lowering is carried out already at a time change in the control rod displacement which brings about a positive load jump, in accordance with a precalculation of temperature T at the catalytic converter (8).
Claim 4
Dependent Claim
31 words
Method according to one of Claims 1 to 3, characterized in that the increase is carried out only when a temperature reduction has actually occurred at the catalytic converter unit (8).
Claim 5
Dependent Claim
69 words
Method according to one of Claims 1 to 4, characterized in that the intermediate value Z 1 ( Ṁ R ) is lowered as the exhaust-gas temperature falls and raised as the exhaust-gas temperature rises if the exhaust-gas temperature at the catalytic converter unit (8) is lower than a temperature T (k max ) at which the catalytic converter unit (8) has a maximum catalytic activity k max .
Claim 6
Dependent Claim
69 words
Method according to one of Claims 1 to 5, characterized in that the intermediate value Z 1 ( Ṁ R ) is lowered as the exhaust-gas temperature rises and raised as the exhaust-gas temperature falls if the exhaust-gas temperature at the catalytic converter unit (8) is higher than the temperature T (k max ) at which the catalytic converter unit (8) has a maximum catalytic activity k max .
Claim 7
Dependent Claim
33 words
Method according to one of Claims 1 to 6, characterized in that the intermediate value is reduced when a maximum space velocity, for which the catalytic converter unit (8) is designed, is exceeded.
Claim 8
Dependent Claim
25 words
Method according to one of Claims 1 to 7 characterized in that the intermediate value is reduced as the duration of operation t B increases.
Claim 9
Dependent Claim
39 words
Method according to Claim 8, characterized in that the intermediate value is reduced in accordance with the exhaust-gas temperatures at the catalytic converter unit (8), which are weighted in accordance with the duration of the operation T B .
Claim 10
Dependent Claim
39 words
Method according to one of Claims 1 to 9, characterized in that the catalytic converter unit (8) is freed from the reducing agent (26) and from hydrocarbons by blue-flame burning before the internal combustion engine is put into operation.
Claim 11
Dependent Claim
53 words
Method according to one of Claims 1 to 10, characterized in that the air mass flow (LM), the control rod displacement (GP), the latter corresponding to the position of the fuel injection device, the charge pressure (LD) and/or the engine speed (MD) are/is provided as the operationally relevant parameter of the engine (4).
Claim 12
Dependent Claim
51 words
Method according to one of Claims 1 to 11, characterized in that the temperature (8), the pressure (AP), the mass flow (AM) and the nitrogen oxide concentration (C NO x ) of the exhaust gas (10), preferably all together, are provided as the operationally relevant parameter of the exhaust gas (10).
Claim 13
Dependent Claim
96 words
Method according to one of Claims 1 to 12, characterized in that the temperature (KT), the catalytic activity (J) with the pressure and temperature profile (k(p) and k(T) respectively), the specific storage capacity C R for the reducing agent (26) with the pressure and temperature profile (C R (p) and C R (T) respectively) and the physical size such as, for example, the weight of the catalytically active mass, the geometry and heat transfer of the catalytic converter unit (8), preferably all together, are provided as the operationally relevant parameter of the catalytic converter unit (8).
Claim 14
Dependent Claim
219 words
Device for the controlled introduction of a reducing agent (26) into a nitrogen oxide-containing exhaust gas (10) of an internal combustion engine (4) with a catalytic converter unit (8) for lowering the nitrogen oxide content installed in the exhaust line (2), for carrying out the method according to one of Claims 1 to 13, characterized in that a monitoring unit (38), means (5, 6, 20, 42, 44), assigned to this monitoring unit (38), for recording at least one operationally relevant parameter of the exhaust gas (10), at least one operationally relevant parameter of the catalytic converter unit (8) and, if required, at least one operationally relevant parameter of the engine (4), and a reducing-agent feed unit (24, 30, 32), assigned to the monitoring unit (38), by means of which a reducing agent (26) can be introduced into the exhaust line (2) ahead of the catalytic converter unit (8) in the direction of flow of the exhaust gas (10), are provided, the monitoring unit (38) being provided for the purpose of adjusting the reducing-agent rate Ṁ R introduced into the exhaust gas (10) as a function of the operationally relevant parameters, specifically taking into account a reducing-agent rate Ṁ A adsorbed by the catalytic converter unit (8) or a reducing-agent rate Ṁ D desorbed by the catalytic converter unit (8).
Claim 15
Dependent Claim
43 words
The device according to Claim 14, characterized in that the catalytic converter unit (8) comprises, in series in the direction of flow of the exhaust gas (10), a hydrolysis catalyst (14), a DeNO x catalyst (16) and, if required, an oxidation catalyst (18).
Claim 16
Dependent Claim
40 words
Device according to Claim 14 or 15, characterized in that the reducing-agent feed unit (24, 30, 32) comprises an introduction valve (24), adjustable by means of the monitoring unit (38), for the reducing agent (26), preferably an aqueous urea solution.
Claim 17
Dependent Claim
104 words
Device according to one of Claims 14 to 16, characterized in that the monitoring unit (38) comprises a memory for all possible parameters of the exhaust gas (10), the catalytic converter unit (8) and, if required, the engine (4) operationally relevant for the determination of the reducing-agent rate Ṁ R , and in that the means (5, 6, 20, 42, 44) call up by means of their signals a corresponding memory value for the reducing-agent rate Ṁ R , the memory value being applied to an output (A 1 ) of the monitoring unit (38) to control the reducing-agent feed unit (24, 30, 32).
Claim 18
Dependent Claim
65 words
Device according to one of Claims 14 to 16, characterized in that the monitoring unit (38) comprises a microprocessor subunit (40) which, by means of a programme, determines the reducing-agent rate Ṁ R from the operationally relevant parameters, recorded by means of the means (5, 6, 20, 40, 44), of the exhaust gas (10), the catalytic converter unit (8) and, if required, the engine (4).
References Cited (Backward Citations)
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