Nitrogen dioxide generation diagnostic for a diesel after-treatment system
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IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F01N-003/20
F01N-003/021
F01N-003/10
F01N-011/00
F01N-013/02
출원번호
US-0442924
(2012-04-10)
등록번호
US-8984867
(2015-03-24)
발명자
/ 주소
Anilovich, Igor
Coppola, John
Kowalkowski, Janean E.
Van Gilder, John F.
Yanakiev, Ognyan N.
출원인 / 주소
GM Global Technology Operations LLC
대리인 / 주소
Quinn Law Group, PLLC
인용정보
피인용 횟수 :
1인용 특허 :
2
초록▼
A method for assessing NO2 generation efficiency in a diesel engine after-treatment (AT) system having a diesel oxidation catalyst (DOC) downstream of the engine generating the NO2 and a selective catalytic reduction (SCR) catalyst downstream of the DOC converting NOX with the aid of the NO2. Engine
A method for assessing NO2 generation efficiency in a diesel engine after-treatment (AT) system having a diesel oxidation catalyst (DOC) downstream of the engine generating the NO2 and a selective catalytic reduction (SCR) catalyst downstream of the DOC converting NOX with the aid of the NO2. Engine exhaust gas flow is passed into the AT system and a reductant is injected into the gas flow between the DOC and the SCR catalyst. SCR inlet gas flow temperature is monitored during transient engine operation and DOC inlet and SCR catalyst outlet NOX concentrations are detected when the SCR catalyst inlet gas flow temperature is in a predetermined range. SCR catalyst NOX conversion efficiency is determined using the detected DOC inlet and SCR catalyst outlet concentrations of NOX. Additionally, whether the NO2 generation efficiency is at or above threshold efficiency is assessed by comparing the determined and threshold NOX conversion efficiencies.
대표청구항▼
1. A system for assessing nitrogen dioxide (NO2) generation efficiency in a diesel engine after-treatment (AT) system, the system for assessing NO2 generation efficiency comprising: an exhaust manifold configured to receive the exhaust gas flow from the engine;a turbocharger connected to the exhaust
1. A system for assessing nitrogen dioxide (NO2) generation efficiency in a diesel engine after-treatment (AT) system, the system for assessing NO2 generation efficiency comprising: an exhaust manifold configured to receive the exhaust gas flow from the engine;a turbocharger connected to the exhaust manifold and configured to pass the exhaust gas flow from the exhaust manifold into the AT system, wherein the AT system includes a diesel oxidation catalyst (DOC) arranged downstream of the engine and configured to generate the NO2, and a selective catalytic reduction (SCR) catalyst arranged downstream of the DOC and configured to convert oxides of nitrogen (NOX) into diatomic nitrogen (N2) and water (H2O) with the aid of the generated NO2; anda controller configured to: inject a reductant into the exhaust gas flow at a location in the AT system downstream of the DOC and upstream of the SCR catalyst;monitor temperature of the exhaust gas flow at the SCR catalyst inlet during transient engine operation;detect a concentration of NOX at the inlet of the DOC and a concentration of NOX at the outlet of the SCR as the engine continues transient operation and the temperature of the exhaust gas flow at the SCR catalyst inlet is in a predetermined range;determine a conversion efficiency of NOX by the SCR catalyst using the detected concentrations of NOX at the inlet of the DOC and at the outlet of the SCR catalyst; andassess whether the NO2 generation efficiency in the AT system is at or above a threshold NO2 generation efficiency by comparing the determined conversion efficiency of NOX with a threshold conversion efficiency of NOX. 2. The system of claim 1, wherein the DOC is close-coupled to the turbocharger. 3. The system of claim 1, wherein the controller is additionally configured to identify the DOC as having failed if the NO2 generation efficiency in the AT system is below the threshold NO2 generation efficiency and generate a signal indicative of the DOC having failed. 4. The system of claim 3, further comprising a first NOX sensor and a second NOX sensor, each sensor arranged in electric communication with the controller, wherein the controller detects the concentration of NOX at the inlet of the DOC via the first NOX sensor and detects the concentration of NOX at the outlet of the SCR catalyst via a second NOX sensor. 5. The system of claim 1, wherein the controller is further configured to assesses whether the NO2 generation efficiency in the AT system is at or above the threshold NO2 generation efficiency by modifying operation of the engine intrusively. 6. The system of claim 1, further comprising a first temperature probe, wherein the controller monitors the temperature of the exhaust gas flow at the SCR catalyst inlet via the first temperature probe, and the predetermined range of the temperature of the exhaust gas flow at the SCR catalyst is 190-215 degrees Celsius. 7. A vehicle comprising: a diesel engine configured to propel the vehicle;an after-treatment (AT) system having a diesel oxidation catalyst (DOC) arranged downstream of the engine and configured to generate the NO2 and a selective catalytic reduction (SCR) catalyst arranged downstream of the DOC and configured to convert oxides of nitrogen (NOX) into diatomic nitrogen (N2) and water (H2O) with the aid of the generated NO2;an exhaust manifold configured to receive the exhaust gas flow from the engine;a turbocharger connected to the exhaust manifold and configured to pass the exhaust gas flow from the exhaust manifold into the AT system; anda controller configured to: regulate injection of a reductant into the exhaust gas flow at a location in the AT system downstream of the DOC and upstream of the SCR catalyst;monitor temperature of the exhaust gas flow at the SCR catalyst inlet during transient engine operation;detect a concentration of NOX at the inlet of the DOC and a concentration of NOX at the outlet of the SCR catalyst as the engine continues transient operation and the temperature of the exhaust gas flow at the SCR catalyst inlet is in a predetermined range;determine a conversion efficiency of NOX by the SCR catalyst using the detected concentrations of NOX at the inlet of the DOC and at the outlet of the SCR catalyst; andassess whether the NO2 generation efficiency in the AT system is at or above a threshold NO2 generation efficiency by comparing the determined conversion efficiency of NOX with a threshold conversion efficiency of NOX. 8. The vehicle of claim 7, wherein the DOC is close-coupled to the turbocharger. 9. The vehicle of claim 7, wherein the controller is additionally configured to identify the DOC as having failed if the NO2 generation efficiency in the AT system is below the threshold NO2 generation efficiency and generate a signal indicative of the DOC having failed. 10. The vehicle of claim 9, further comprising a first NOX sensor and a second NOX sensor, each sensor arranged in electric communication with the controller, wherein the controller detects the concentration of NOX at the inlet of the DOC via the first NOX sensor and detects the concentration of NOX at the outlet of the SCR catalyst via a second NOX sensor. 11. The vehicle of claim 7, wherein the controller is further configured to assesses whether the NO2 generation efficiency in the AT system is at or above the threshold NO2 generation efficiency by modifying operation of the engine intrusively. 12. The vehicle of claim 7, further comprising a first temperature probe, wherein the controller monitors the temperature of the exhaust gas flow at the SCR catalyst inlet via the first temperature probe, and the predetermined range of the temperature of the exhaust gas flow at the SCR catalyst is 190-215 degrees Celsius. 13. A method of assessing nitrogen dioxide (NO2) generation efficiency in a diesel engine after-treatment (AT) system, the method comprising: passing the exhaust gas flow from the engine into the AT system, wherein the AT system includes a diesel oxidation catalyst (DOC) arranged downstream of the engine and configured to generate the NO2, and a selective catalytic reduction (SCR) catalyst arranged downstream of the DOC and configured to convert oxides of nitrogen (NOX) into diatomic nitrogen (N2) and water (H2O) with the aid of the generated NO2;injecting a reductant into the exhaust gas flow at a location in the AT system downstream of the DOC and upstream of the SCR catalyst;monitoring temperature of the exhaust gas flow at the SCR catalyst inlet during transient engine operation;detecting a concentration of NOX at the inlet of the DOC and a concentration of NOX at the outlet of the SCR catalyst as the engine continues transient operation and the temperature of the exhaust gas flow at the SCR catalyst inlet is in a predetermined range;determining a conversion efficiency of NOX by the SCR catalyst using the detected concentrations of NOX at the inlet of the DOC and at the outlet of the SCR catalyst; andassessing whether the NO2 generation efficiency in the AT system is at or above a threshold NO2 generation efficiency by comparing the determined conversion efficiency of NOX with a threshold conversion efficiency of NOX. 14. The method of claim 13, wherein the engine includes an exhaust manifold configured to receive the exhaust gas flow from the engine, and a turbocharger connected to the exhaust manifold and configured to pass the exhaust gas flow from the exhaust manifold into the AT system, and wherein the DOC is close-coupled to the turbocharger. 15. The method of claim 13, wherein the DOC is determined to have failed if the NO2 generation efficiency in the AT system is below the threshold NO2 generation efficiency, further comprising generating a signal indicative of the DOC having failed. 16. The method of claim 15, wherein each of said injecting the reductant into the exhaust gas flow, determining the conversion efficiency of NOX by the SCR catalyst; assessing whether the NO2 generation efficiency in the AT system is at or above a threshold NO2 generation efficiency, and generating the signal that the DOC has failed is accomplished by a controller. 17. The method of claim 16, wherein said detecting the concentration of NOX at the inlet of the DOC is accomplished via a first NOX sensor arranged in electric communication with the controller and the concentration of NOX at the outlet of the SCR catalyst is accomplished via a second NOX sensor arranged in electric communication with the controller. 18. The method of claim 16, wherein said assessing whether the NO2 generation efficiency in the AT system is at or above a threshold NO2 generation efficiency includes modifying operation of the engine intrusively by the controller. 19. The method of claim 13, wherein the reductant is urea that is injected into a passage configured to direct the exhaust gas flow from the DOC to the SCR catalyst. 20. The method of claim 13, wherein said determining the conversion efficiency of NOX by the SCR catalyst is determined by averaging the detected concentrations of NOX.
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Zha, Yuhui; Heichelbech, John K; Cunningham, Michael J., Systems and methods for increasing nitrogen dioxide fraction in exhaust gas at low temperature.
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