US5832722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for maintaining catalyst efficiency of a NOx trap
Assignee: Ford Global Technologies LLC
•
Filing: 1997-03-31
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Granted: 1998-11-10
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Expires: 2017-03-31
Abstract
Abstract An engine control computer estimates the cumulative SO x stored in a NO x trap and enters a SO x purge mode of operation when a maximum storage capacity limit is exceeded. SO x accumulation is estimated based on fuel flow to the engine, A/F and trap temperature. The purge mode is terminated when the estimated SO x storage level drops below a minimum threshold level during the purging operation.
Inventors
- 👤 Michael John Cullen
- 👤 David George Farmer
- 👤 Arnold William Brandt
- 👤 Jeffrey Scott Hepburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:04
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/0807; F01N3/0828; F01N3/0842; B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8696; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9431; B01D53/9495; F01N3/0871; F01N3/0885; F01N3/10; F01N3/18; F01N3/22; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/027; F02D41/0275; F02D41/028; F01N2570/00; F01N2570/04; F01N3/24; F01N3/30; F01N3/32; F02D2200/00; F02D2200/02; F02D2200/08; F02D2200/0818; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
101 words
A method of estimating the amount of SO x accumulated in a NO x trap located in an exhaust passage of an engine comprising a sequence of the steps of: determining an amount of SO x accumulated per unit fuel flow, based on present A/F and present temperature of said trap; calculating the rate of SO x accumulation based on said determined amount of SO x and the flow rate of fuel supplied to said engine; and calculating the amount of S0 x accumulation based on said calculated rate of SO x accumulation and the elapsed time since a previous calculation.
Claim 2
Independent Claim
101 words
A method of estimating the amount of SO x accumulated in a NO x trap located in an exhaust passage of an engine comprising a sequence of the steps of: determining an amount of SO x accumulated per unit fuel flow, based on present A/F and present temperature of said trap; calculating the rate of SO x accumulation based on said determined amount of SO x and the flow rate of fuel supplied to said engine; and calculating the amount of S0 x accumulation based on said calculated rate of SO x accumulation and the elapsed time since a previous calculation.
Claim 3
Dependent Claim
33 words
The method defined in claim 1 further comprising the step of: adding the amount of SO x stored since said previous calculation to the calculated amount previously stored to obtain a cumulative amount.
Claim 4
Dependent Claim
51 words
The method defined in claim 2 further comprising the steps of: comparing the cumulative amount of SO x stored with a maximum capacity level; and initiating a SO x purge operation when said maximum capacity level is exceeded in order to reduce the amount of SO x stored in said trap.
Claim 5
Dependent Claim
34 words
The method defined in claim 3 wherein said purge operation comprises the steps of: controlling the temperature of said trap above a predetermined minimum purging temperature; and operating said engine at a rich A/F.
Claim 6
Dependent Claim
32 words
The method defined in claim 4 comprising the further steps of: terminating said purge operation when the amount of SO x stored in said trap is less than a minimum capacity level.
Claim 7
Dependent Claim
26 words
The method defined in claim 2 wherein said determined amount is positive when said engine is operating lean and negative when said engine is operating rich.
Claim 8
Dependent Claim
130 words
Apparatus for estimating the amount of SO x accumulated in a NO x trap located in an exhaust passage of an engine comprising: a read only memory containing experimentally determined data representing the expected amount of SO x that would be accumulated in said trap per quantity of fuel supplied to said engine at a specified A/F and trap temperature; an engine controller for estimating the temperature of said trap, and for calculating the desired fuel quantity to achieve a desired A/F; said controller calculating the incremental amount of SO x accumulated in said trap since the previous calculation based on the product of the read only memory data, corresponding to the present A/F and trap temperature, and the amount of fuel supplied to said engine since the previous calculation.
Claim 9
Dependent Claim
130 words
Apparatus for estimating the amount of SO x accumulated in a NO x trap located in an exhaust passage of an engine comprising: a read only memory containing experimentally determined data representing the expected amount of SO x that would be accumulated in said trap per quantity of fuel supplied to said engine at a specified A/F and trap temperature; an engine controller for estimating the temperature of said trap, and for calculating the desired fuel quantity to achieve a desired A/F; said controller calculating the incremental amount of SO x accumulated in said trap since the previous calculation based on the product of the read only memory data, corresponding to the present A/F and trap temperature, and the amount of fuel supplied to said engine since the previous calculation.
Claim 10
Dependent Claim
32 words
The apparatus of claim 7 wherein said controller adds said incremental amount to a previously calculated total amount of accumulated SO x to obtain a cumulative amount of stored SO x .
Claim 11
Dependent Claim
35 words
The apparatus of claim 8 wherein said controller compares said cumulative amount of stored SO x with a maximum capacity level and initiating a SO x purge operation when said maximum capacity level is exceeded.
Claim 12
Dependent Claim
48 words
The apparatus defined in claim 9 wherein said controller operates said engine at a rich A/F and controls the amount of secondary air added to said exhaust, upstream of said trap, to maintain the temperature of said trap above a predetermined minimum purging temperature during said purge operation.
Claim 13
Dependent Claim
30 words
The apparatus defined in claim 10 wherein said controller terminates said purge operation when the amount of SO x stored in said trap is less than a minimum capacity level.
Claim 14
Dependent Claim
30 words
The apparatus defined in claim 8 wherein said read only memory contains data that is positive when said engine is operating lean and negative when said engine is operating rich.
Claim 15
Dependent Claim
87 words
An article of manufacture comprising: a computer storage medium having a computer program encoded therein for controlling the amount of fuel supplied to an engine having an exhaust passage with a NO x trap located therein, said computer storage medium comprising: code for determining the temperature of said trap; code for calculating the amount of fuel to be delivered to said engine to achieve a desired A/F; and code for calculating the incremental amount of SO x accumulated in said trap at said A/F and trap temperature.
Claim 16
Dependent Claim
87 words
An article of manufacture comprising: a computer storage medium having a computer program encoded therein for controlling the amount of fuel supplied to an engine having an exhaust passage with a NO x trap located therein, said computer storage medium comprising: code for determining the temperature of said trap; code for calculating the amount of fuel to be delivered to said engine to achieve a desired A/F; and code for calculating the incremental amount of SO x accumulated in said trap at said A/F and trap temperature.
Claim 17
Dependent Claim
28 words
The article defined in claim 13 wherein said medium further comprises: code for adding said incremental amount to a previously calculated total amount of accumulated SO x .
Claim 18
Dependent Claim
40 words
The article defined in claim 14 wherein said medium further comprises: code for comparing said total amount of accumulated SO x with a maximum capacity level and initiating a SO x purge operation when said maximum capacity level is exceeded.
Claim 19
Dependent Claim
33 words
The article defined in claim 15 wherein the incremental amount of SO x accumulated in said trap is a function of the amount of fuel supplied to said engine since the previous calculation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-09 | 2002-05-11 | 2002-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-09 | 2006-05-11 | 2006-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-09 | 2010-05-11 | 2010-11-10 | $7700.00 | Window Closed / Lapsed |