Engine exhaust treatment apparatus and method of use
First Claim
1. An engine exhaust treatment apparatus for abating pollutants contained in the exhaust stream of the engine, the apparatus defining a flow path for the exhaust stream and comprising:
- (a) an upstream catalyst member comprising an upstream catalytic material effective for catalyzing the oxidation of hydrocarbons and comprising a platinum group metal component dispersed on a refractory metal oxide first support, the upstream catalyst being substantially free of oxygen storage components; and
(b) a downstream catalyst member comprising a downstream catalytic material effective at least for the oxidation of hydrocarbons and comprising one or more catalytic metal components dispersed on a refractory metal oxide support and further comprising an oxygen storage component.
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Abstract
An exhaust gas treatment apparatus and method for its use includes an upstream catalyst and a downstream catalyst. The upstream catalyst contains a catalytic metal effective at least for the oxidation of hydrocarbons in the exhaust gas stream, and preferably contains a palladium catalytic component and contains substantially no oxygen storage components, i.e., oxides of cerium, cobalt, iron, magnesium, molybdenum, nickel, praseodymium, tungsten and vanadium, but the downstream catalyst includes an oxygen storage component. Preferably, the upstream catalyst is a close-coupled catalyst. The downstream catalyst may be an underfloor catalyst or a close-coupled catalyst, in which case there is, preferably, an additional, underfloor catalyst.
92 Citations
28 Claims
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1. An engine exhaust treatment apparatus for abating pollutants contained in the exhaust stream of the engine, the apparatus defining a flow path for the exhaust stream and comprising:
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(a) an upstream catalyst member comprising an upstream catalytic material effective for catalyzing the oxidation of hydrocarbons and comprising a platinum group metal component dispersed on a refractory metal oxide first support, the upstream catalyst being substantially free of oxygen storage components; and
(b) a downstream catalyst member comprising a downstream catalytic material effective at least for the oxidation of hydrocarbons and comprising one or more catalytic metal components dispersed on a refractory metal oxide support and further comprising an oxygen storage component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 25, 26, 27, 28)
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12. An engine exhaust treatment apparatus for abating pollutants contained in the exhaust stream of the engine, the apparatus defining a flow path for the exhaust stream and comprising:
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(a) a first close-coupled catalyst member comprising a first catalytic material effective for catalyzing the oxidation of hydrocarbons and comprising a palladium catalytic component dispersed on a refractory metal oxide first support, the first catalytic material being substantially free of rhodium and oxygen storage components;
(b) a second close-coupled catalyst member comprising a second catalytic material effective at least for the oxidation of hydrocarbons; and
(c) an underfloor catalyst member comprising a third catalytic material effective for three-way abatement of pollutants;
wherein at least one of the second close-coupled downstream catalyst member and the underfloor member comprise an oxygen storage component. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
not more than about 0.5 g/in3 of zirconium oxide incorporated into the support material; and
not more than about 0.5 g/in3 of at least one rare earth metal oxide selected from the group consisting of lanthanum oxide and neodymium oxide.
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16. The apparatus of claim 15 wherein the first close-coupled catalyst member comprises at least 60 g/ft3 of a platinum group metal component and wherein the platinum group metal component principally comprises a palladium component.
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17. The apparatus of claim 15 wherein the first close-coupled catalyst member comprises from about 75 to about 300 g/ft3 of the platinum group metal component.
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18. The apparatus of claim 16 wherein the first close-coupled catalyst member comprises from about 0.75 to about 2.0 g/in3 of activated alumina support material;
- and at least one component selected from the group consisting of;
from about 0.05 to about 0.4 g/in3 of strontium oxide;
from about 0.05 to about 0.2 g/in3 of barium oxide;
from about 0.025 to about 0.3 g/in3 of lanthanum oxide;
from about 0.025 to about 0.3 g/in3 of neodymium oxide; and
from about 0.05 to about 0.5 g/in3 of zirconium oxide.
- and at least one component selected from the group consisting of;
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19. The apparatus of claims 14, 15 or 16 wherein the first close-coupled catalyst member comprises about 300 g/ft3 palladium, 1.23 g/in3 alumina, 0.19 g/in3 lanthanum oxide, 0.1 g/in3 zirconium oxide, 0.1 g/in3 strontium oxide and 0.16 g/in3 neodymiun oxide;
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wherein the second close-coupled catalyst member comprises about 110 g/ft3 palladium, 1.4 g/in3 alumina, 0.8 g/in3 cerium oxide, 0.5 g/in3 cerium oxide-zirconium oxide composite, 0.24 g/in3 zirconium oxide, 0.2 g/in3 lanthanum oxide, 0.1 g/in3 neodymium oxide, 0.1 g/in3 strontium oxide, 0.07 g/in3 nickel oxide and 0.06 g/in3 barium oxide; and
wherein the underfloor catalyst comprising about 91.9 g/ft3 palladium, 6.56 g/ft3 rhodium, 6.56 g/ft3 platinum, 1.5 g/in3 alumina, 1.7 g/in3 cerium oxide-zirconium oxide composite, 0.1 g/in3 neodymium oxide, 0.25 g/in3 strontium oxide, 0.125 g/in3 zirconium oxide, and 0.075 g/in3 lanthanum oxide.
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- 20. A method for treating the exhaust of an engine having an exhaust gas outlet, the method comprising flowing the exhaust gas from the exhaust gas outlet of the engine to an upstream catalyst member comprising an upstream catalytic material effective at least for the oxidation of hydrocarbons and comprising a platinum group metal component dispersed on a refractory inorganic oxide support, the upstream catalytic material being substantially free of oxygen storage components, and then flowing the exhaust gas to at least one catalyst member downstream of the upstream catalyst member, the at least one downstream catalyst member comprising a downstream catalytic material effective at least for the oxidation of hydrocarbons comprising at least one oxygen storage component.
Specification