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US 12,416,254 B2Granted
Performance enhancement of a catalyst via exhaust gas hydrogen enrichment
AssigneeBASF Mobile Emissions Catalysts LLC
InventorsShiang Sung, Chunxin Ji, Pavel Ruvinskiy
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Abstract
The disclosure provides a system for treating an exhaust gas stream from a gasoline engine. The system is configured to introduce controlled quantities of hydrogen gas into the exhaust gas stream upstream of a catalyst article during a cold-start period. Further provided are related methods of treating such exhaust streams. Such systems and methods are useful in reducing a level of one or more of hydrocarbons, carbon monoxide, and nitrogen oxide in a gaseous exhaust stream from a gasoline engine.
Claims24
A system for treating an exhaust gas stream from a gasoline engine, the system comprising:
- a catalyst article downstream of and in fluid communication with the gasoline engine, wherein the catalyst article comprises a substrate, a first catalyst layer disposed on the substrate, and a second catalyst layer disposed on the first catalyst layer, wherein:
- the first catalyst layer comprises a first palladium component, a first refractory metal oxide support, and a first oxygen storage component, wherein at least a portion of the first palladium component is impregnated on the first refractory metal oxide support, and another portion of the first palladium component is impregnated on the first oxygen storage component;
- and
- the second catalyst layer comprises a second palladium component, a second refractory metal oxide support, a second oxygen storage component, a rhodium component,
- and a third refractory metal oxide support, wherein at least a portion of the second palladium component is impregnated on the second refractory metal oxide support, and another portion of the second palladium component is impregnated on the second oxygen storage component, and the rhodium component is impregnated on the third refractory metal oxide support;
- a source of hydrogen gas (H2);
- a feedback sensor located upstream from the catalyst article and in contact with the exhaust gas stream, wherein the feedback sensor comprises a wide-band oxygen sensor (UEGO) and a temperature sensor;
- and
- a control unit in communication with the feedback sensor;
- an H2 injection article upstream from the catalyst article, upstream from the feedback sensor, in fluid communication with the exhaust gas stream and with the H2 source, and in communication with the control unit;
- and wherein the H2 injection article configured to introduce H2 from the H2 source into the exhaust gas stream upstream of the catalyst article;
- wherein the system is configured to introduce H2 from the H2 source into the exhaust gas stream upstream of the catalyst article during a cold-start period, and wherein the system is configured to introduce H2 from the H2 source into the exhaust gas stream when the exhaust gas stream temperature upstream of or within the catalytic article is in a range from about 90° C. to about 190° C., wherein the feedback sensor is configured to provide H2 in the exhaust gas stream by modulating the H2 introduction;
- wherein the system is configured to introduce H2 from the H2 source into the exhaust gas stream to provide a Δλ value of from about −0.014 to no more negative than about −0.345 for a period of time, wherein:
- Δλ
- =
- λ
- ¯
- -
- λ°
- ;
- λ° is a pre-defined value;
- and
- λ is a running average air-to-fuel ratio of the exhaust gas stream, calculated for a length of time according to the formula:
- λ
- ¯
- =
- ∑
- i
- =
- 1
- N
-
- λ
- i
- N
- ;
- wherein (N) is the number of points comprised in this length of time, and λi is the air-to-fuel ratio at each point.
34 more elements
A method of treating an exhaust gas stream from a gasoline engine, the method comprising:
- contacting the exhaust gas stream with a catalyst article located downstream of the gasoline engine and in fluid communication with the exhaust gas stream, wherein the catalyst article comprises a substrate, a first catalyst layer disposed on the substrate, and a second catalyst layer disposed on the first catalyst layer, wherein:
- the first catalyst layer comprises a first palladium component, a first refractory metal oxide support, and a first oxygen storage component, wherein at least a portion of the first palladium component is impregnated on the first refractory metal oxide support, and another portion of the first palladium component is impregnated on the first oxygen storage component;
- and
- the second catalyst layer comprises a second palladium component, a second refractory metal oxide support, a second oxygen storage component, a rhodium component, and a third refractory metal oxide support, wherein at least a portion of the second palladium component is impregnated on the second refractory metal oxide support, and another portion of the second palladium component is impregnated on the second oxygen storage component, and the rhodium component is impregnated on the third refractory metal oxide support;
- introducing hydrogen gas (H2) from a H2 source via an H2 injection article into the exhaust gas stream upstream of the catalyst article, upstream from a feedback sensor, in fluid communication with the exhaust gas stream and with the H2 source into the exhaust gas stream upstream of the catalyst article, wherein the feedback sensor comprises a wide-band oxygen sensor (UEGO) and a temperature sensor;
- and
- controlling a concentration by volume of H2 in the exhaust gas stream upstream from the catalyst article, wherein controlling the concentration by volume of H2 comprises modulating the H2 introduction, wherein controlling comprises introducing H2 into the exhaust gas stream when a temperature of the exhaust gas stream upstream from or inside the catalyst article is in a range from about 90° C. to about 550° C., or from about 90° C. to about 190° C.;
- introducing H2 into the exhaust gas stream;
- and
- providing a Δλ value no more negative than about −0.345 for a period of time, wherein:
- Δλ
- =
- λ
- ¯
- -
- λ°
- ;
- λ° is a pre-defined value;
- and
- λ is a running average air-to-fuel ratio of the exhaust gas stream, calculated for a length of time according to the formula:
- λ
- ¯
- =
- ∑
- i
- =
- 1
- N
-
- λ
- i
- N
- ;
- wherein (N) is the number of points comprised in this length of time, and λi is the air-to-fuel ratio at each point.
31 more elements
Dependencies are inferred from the claim text.