Method for adjusting a reductant used in an internal combustion engine to reduce NOx
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B01D-053/56
출원번호
US-0186690
(2002-07-01)
등록번호
US-7320781
(2008-01-22)
발명자
/ 주소
Lambert,Christine Kay
Adams,Karen Marie
Hammerle,Robert Henry
출원인 / 주소
Lambert,Christine Kay
Adams,Karen Marie
Hammerle,Robert Henry
대리인 / 주소
Brehob,Diana D.
인용정보
피인용 횟수 :
11인용 특허 :
16
초록▼
A method for controlling reductant injection into an exhaust stream upstream of a catalyst coupled to an internal combustion engine is disclosed. In the method, an ammonia sensor located downstream of the exhaust catalyst is used to determine ammonia concentration in the exhaust stream. The ammonia
A method for controlling reductant injection into an exhaust stream upstream of a catalyst coupled to an internal combustion engine is disclosed. In the method, an ammonia sensor located downstream of the exhaust catalyst is used to determine ammonia concentration in the exhaust stream. The ammonia concentration is compared to an allowable threshold and an allowable fraction, i.e., a maximum limit on a fraction of ammonia in the exhaust stream compared with the ammonia supplied by the reductant injector. Additionally, based on a NOx sensor, it is determined whether NOx conversion of the catalyst has increased in response to an increase in reductant injection. If not, reductant injection quantity is reduced.
대표청구항▼
We claim: 1. A method for controlling reductant injection into a catalyst coupled to an internal combustion engine, the method comprising: determining a reductant fraction based on an amount of reductant used in the catalyst and an amount of the reductant passing through the catalyst, said fraction
We claim: 1. A method for controlling reductant injection into a catalyst coupled to an internal combustion engine, the method comprising: determining a reductant fraction based on an amount of reductant used in the catalyst and an amount of the reductant passing through the catalyst, said fraction representative of a fractional amount of reductant used in a reaction in the catalyst, wherein the fractional amount is based on a desired ratio between ammonia in the supplied reductant and NOx exhausted from the engine; varying the reductant injection in accordance with both said determined reductant fraction and an amount of reductant exiting the catalyst, and where said varying further includes increasing said reductant injection only when such increase provides increased NOx conversion in the catalyst; and wherein said engine is a diesel engine in a vehicle. 2. The method of claim 1 wherein said varying comprises increasing said amount of reductant injection when said amount of reductant passing from the catalyst is less than an allowable level of post catalyst reductant and said reductant fraction is less than an allowable reductant fraction. 3. The method of claim 2, further composing increasing said amount of reductant injection by a predetermined amount. 4. The method of claim 2, further comprising: determining a NOx conversion value at a time prior to said increasing step; determining a NOx conversion value at a time after said increasing step; and decreasing said amount of reductant injection when said NOx conversion value after said increasing step is greater than said NOx conversion value prior to said reductant increasing. 5. The method of claim 4 wherein said NOx conversion value is based on a value of NOx concentration upstream of the catalyst and a value of NOx concentration downstream of the catalyst. 6. The method of claim 5 wherein said value of NOx concentration upstream of the catalyst is determined based on engine operating conditions. 7. The method of claim 1 wherein said varying comprises decreasing said amount of reductant injection when said reductant concentration passing from the catalyst is greater than an allowable level or said reductant fraction is greater than an allowable reductant fraction. 8. The method recited in claim 7, further comprising decreasing said amount of reductant injection when said reductant concentration downstream of the catalyst is greater than an allowable level of post-catalyst reductant. 9. The method of claim 8, further comprising decreasing said amount of reductant injection when said reductant fraction is greater than an allowable reductant fraction. 10. The method of claim 9 wherein decreasing said amount of reductant injection decreases said amount of reductant injection by a predetermined amount. 11. The method of claim 10, wherein said varying comprises increasing said amount of reductant injection when said amount of reductant passing from the catalyst is less than an allowable level and said reductant fraction is less than an allowable reductant fraction. 12. A method for controlling reductant injection into a catalyst coupled to an internal combustion engine, the method comprising: determining a reductant fraction based on an amount of reductant used in the catalyst and an amount of the reductant passing through the catalyst, said fraction representative of a fractional amount of reductant used in a reaction in the catalyst, wherein the fractional amount is based on a desired ratio between ammonia in the supplied reductant and NOx exhausted from the engine; varying the reductant injection in accordance with both said determined reductant fraction and an amount of reductant exiting the catalyst, wherein said varying further comprises decreasing said amount of reductant injection when said reductant concentration passing from the catalyst is greater than an allowable level or said reductant fraction is greater than an allowable reductant fraction, decreasing said amount of reductant injection when said reductant concentration downstream of the catalyst is greater than an allowable level of post-catalyst reductant, and decreasing said amount of reductant injection when said reductant fraction is greater than an allowable reductant fraction; and wherein said engine is a diesel engine in a vehicle. 13. The method of claim 12 wherein said varying comprises increasing said amount of reductant injection when said amount of reductant passing from the catalyst is less than an allowable level of post catalyst reductant and said reductant fraction is less than an allowable reductant fraction. 14. The method of claim 13, further comprising increasing said amount of reductant injection by a predetermined amount. 15. The method of claim 13, further comprising: determining a NOx conversion value at a time prior to said increasing step; determining a NOx conversion value at a time after said increasing step; and decreasing said amount of reductant injection when said NOx conversion value after said increasing step is greater than said NOx conversion value prior to said reductant increasing. 16. The method of claim 15, wherein said NOx conversion value is based on a value of NOx concentration upstream of the catalyst and a value of NOx concentration downstream of the catalyst. 17. The method of claim 16, wherein said value of NOx concentration upstream of the catalyst is determined based on engine operating conditions. 18. A method for controlling reductant injection into a catalyst coupled to an internal combustion engine, the method comprising: determining a reductant fraction based on an amount of reductant used in the catalyst and an amount of the reductant passing through the catalyst, said fraction representative of a fractional amount of reductant used in a reaction in the catalyst, wherein the fractional amount is based on a desired ratio between ammonia in the supplied reductant and NOx exhausted from the engine; varying the reductant injection in accordance with both said determined reductant fraction and an amount of reductant exiting the catalyst, wherein said varying comprises increasing said amount of reductant injection when said amount of reductant passing from the catalyst is less than an allowable level of post catalyst reductant and said reductant fraction is less than an allowable reductant fraction, and further comprising increasing said amount of reductant injection by a predetermined amount; and wherein said engine is a diesel engine in a vehicle.
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이 특허에 인용된 특허 (16)
Krishnamurthy Sowmithri (Cherry Hill NJ) McWilliams John P. (Woodbury NJ) Pappal David A. (Sewell NJ) Sigal Catherine T. (Pennington NJ) Kiliany ; Jr. Thomas R. (Baytown TX), Abatement of NOx in exhaust gases.
Dahlheim Christian (Berlin DEX) Fleischer Maximilian (Hoehenkirchen DEX) Meixner Hans (Haar DEX), Method for reducing the nitrogen oxide concentration in the exhaust of an internal combustion engine or of a firing syst.
Brand Reinhold (Hanau DEX) Engler Bernd (Hanau DEX) Kleine-Moellhoff Peter (Alzenau DEX) Koberstein Edgar (Alzenau DEX), Method for the catalytic removal of nitrogen oxides from exhaust gases by means of a reducing agent.
Michalak Stanislaw (Hespert DEX) Weber Klaus-Dieter (Reichshof DEX) Meier Jrgen (Wiehl DEX), Method of regulating the amount of reducing agent added during catalytic reduction of NOx contained in flu.
Chi, John N.; Wang, Weiwen; Garimella, Phanindra; Hill, Joe V., Apparatus, system, and method for controlling reductant dosing in an SCR catalyst system.
Garimella, Phanindra; Osburn, Andy; Chi, John N.; Wills, Joan M., Apparatus, system, and method for estimating an NOx conversion efficiency of a selective catalytic reduction catalyst.
Chi, John N.; Hill, Joe V.; Wills, Joan M.; Farrell, Lisa A.; Frazier, Timothy R.; Mohammed, Hasan, Apparatus, system, and method for reducing NOx emissions from an engine system.
Wills, Joan M.; Chi, John N.; Wang, Weiwen; Garimella, Phanindra; Frazier, Timothy R.; Ofoli, Abdul R.; Hill, Joe V.; Farrell, Lisa A.; Currier, Neal W.; Yezerets, Aleksey; Osburn, Andy, Apparatus, system, and method for reducing NOx emissions on an SCR catalyst.
Bauer, Peter; Bentz, Rainer; Fokkelman, Joris; Frank, Joachim; Ketterl, Hermann; Koops, Ingo; Leinfelder, Robert, Method for detecting the minimum opening time of a reducing agent feed device in an exhaust gas aftertreatment system comprising an SCR catalyst.
Kraemer, Gilbert Otto; Frederick, Garth Curtis, Model-based tuning of ammonia distribution and control for reduced operating cost of selective catalytic reduction.
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