摘要:
An exhaust gas purification catalyst has a substrate, a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt, and an upper catalyst layer that is formed on the lower catalyst layer and contains Rh. A region that does not contain the upper catalyst layer is disposed on the exhaust gas upstream side of this exhaust gas purification catalyst. The lower catalyst layer includes a front-stage lower catalyst layer on the exhaust gas upstream side and a rear-stage lower catalyst layer on the exhaust gas downstream side. The front-stage lower catalyst layer contains an oxygen storage material.
摘要:
An exhaust gas purifying catalyst that contains a first oxygen storage material on which no noble metal is supported and which has a pyrochlore phase type regular array structure, and a second oxygen storage material which has a higher oxygen storage rate and a lower oxygen storage capacity than the first oxygen storage material and on which a platinum group noble metal is supported.
摘要:
A catalytic support 10 is made of rare-earth-element-oxide fine particles (e.g., ceria fine particles 11) comprising primary particles of a rare-earth element oxide, alumina fine particles 12 comprising primary particles of alumna, and barium-compound fine particles 13 comprising primary particles of a barium compound, rare-earth-element-oxide fine particles, alumina fine particles 12 and barium-compound fine particles 13 which are mixed with each other. A primary particle diameter of the rare-earth-element-oxide fine particles is 5 nm or less, and a primary particle diameter of the barium-compound fine particles 13 is 10 nm or less. Platinum fine particles 20 are supported, of this catalytic support 10, on the rare-earth-element-oxide fine particles virtually. It is possible to suppress the granular growth of platinum, which serves an oxidizing catalyst, and the granular growth of barium, which serves an NOx storage material, more securely.
摘要:
An exhaust purifying catalyst includes: a substrate; a first-stage catalyst that includes an oxygen storage capacity (OSC) material and that is provided on the substrate on an upstream side thereof in an exhaust gas flow direction; and a second-stage catalyst that includes an OSC material and that is provided on the substrate on a downstream side thereof in an exhaust gas flow direction. The OSC material included in the first-stage catalyst and the second-stage catalyst includes OSC material on which a noble metal is not supported. The proportion of the amount of the OSC material, on which a noble metal is not supported, and that is included in the second-stage catalyst with respect to the combined amount of the OSC material, on which a noble metal is not supported, and that is included in the first-stage catalyst and the second-stage catalyst is in a range of from 0 to 50 wt %.
摘要:
An exhaust purifying catalyst includes: a substrate; a first-stage catalyst that includes an oxygen storage capacity (OSC) material and that is provided on the substrate on an upstream side thereof in an exhaust gas flow direction; and a second-stage catalyst that includes an OSC material and that is provided on the substrate on a downstream side thereof in an exhaust gas flow direction. The OSC material included in the first-stage catalyst and the second-stage catalyst includes OSC material on which a noble metal is not supported. The proportion of the amount of the OSC material, on which a noble metal is not supported, and that is included in the second-stage catalyst with respect to the combined amount of the OSC material, on which a noble metal is not supported, and that is included in the first-stage catalyst and the second-stage catalyst is in a range of from 0 to 50 wt %.
摘要:
An exhaust gas control apparatus for an internal combustion engine includes a NOx purification catalyst disposed in an exhaust passage of the internal combustion engine and carrying a first catalyst metal on a first catalyst carrier, an oxidation catalyst disposed in the downstream exhaust passage of the NOx purification catalyst and carrying second catalyst metals including a base metal on a second catalyst carrier, an air introduction apparatus introducing air into an upstream of the oxidation catalyst, and a temperature detector detecting a temperature of the oxidation catalyst. When an oxidation catalyst temperature is a predetermined temperature or lower, an air-fuel ratio of the exhaust gas into the oxidation catalyst is controlled to a more fuel lean ratio than the stoichiometric air-fuel ratio. When the oxidation catalyst temperature exceeds the predetermined temperature, the air-fuel ratio of the exhaust gas into the oxidation catalyst is controlled to the stoichiometric air-fuel ratio.
摘要:
A catalyst system for exhaust gas purification which comprises a first-stage base metal catalyst located upstream and a second-stage base metal catalyst located downstream, wherein the first-stage base metal catalyst comprises at least one oxide support selected from the group consisting of alumina, ceria, zirconia, yttria, and titania and Cu metal and/or a Cu oxide supported thereon, and in cases where the amount of NOx in the exhaust gas has become or exceeded an NOx criterion, the state of the exhaust gas is switched from slightly rich to rich.
摘要:
Provided is an exhaust purification system for an internal combustion engine. The exhaust purification system comprising: a NOX purifying catalyst arranged in an exhaust passage of the internal combustion engine, wherein the NOX purifying catalyst comprises a base metal supported on a catalyst support; an oxygen sensor arranged at the downstream side of the NOX purifying catalyst in the exhaust passage; and an air-fuel, ratio control means for controlling the air-fuel ratio of exhaust gas flowing into the NOX purifying catalyst; wherein when the NOX purifying catalyst suffers from predetermined oxygen poisoning, the air-fuel ratio control means controls the air-fuel ratio of the exhaust gas, which flows into the NOX purifying catalyst, to a first air-fuel ratio wherein the first air-fuel ratio is richer than a theoretical air-fuel ratio, and then the air-fuel ratio control means switches the air-fuel ratio of the exhaust gas, which flows into the NOX purifying catalyst, to a second air-fuel ratio on the basis of an output value from the oxygen sensor wherein the second air-fuel ratio is leaner than the first air-fuel ratio.
摘要:
The invention relates to an exhaust gas purification device of an internal combustion engine comprising a catalyst (45) having an active element and a composite oxidation which carries the active element in an exhaust passage (40), the active element transforming into the composite oxide as a solid solution when the catalyst temperature is higher than or equal to a predetermined solid solution temperature and the atmosphere of the interior of the catalyst is an oxidation atmosphere and the active element precipitating from the composite oxide when the catalyst temperature is higher than or equal to a predetermined precipitation temperature and the atmosphere of the interior of the catalyst is a reduction atmosphere. According to the invention, in case that the performance of the fuel supply stop control is inhibited when the catalyst temperature is higher than or equal to the performance inhibiting temperature, a temperature lower than a base temperature of the performance inhibiting temperature is set as the performance inhibiting temperature while the use degree of the catalyst is lower than or equal to a predetermined degree and in case that the performance of the fuel supply amount increase control is permitted when the catalyst temperature is higher than or equal to a performance permitting temperature, a temperature higher than a base temperature of the performance permitting temperature is set as the performance permitting temperature while the use degree of the catalyst is smaller than or equal to the predetermined degree.
摘要:
A catalyst system for exhaust gas purification which comprises a first-stage base metal catalyst located upstream and a second-stage base metal catalyst located downstream, wherein the first-stage base metal catalyst comprises at least one oxide support selected from the group consisting of alumina, ceria, zirconia, yttria, and titania and Cu metal and/or a Cu oxide supported thereon, and in cases where the amount of NOx in the exhaust gas has become or exceeded an NOx criterion, the state of the exhaust gas is switched from slightly rich to rich.