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US 7,442,346 B2Granted
Device for the purification of exhaust gas
AssigneeNissan Motor Co., Ltd.
InventorsTakuya Ikeda, Maki Kamikubo
Life of this patent
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Abstract
As a device for the purification of exhaust gas, a three-way catalyst A purifying hydrocarbon, carbon monoxide and nitrogen oxide in the vicinity of theoretical air-fuel ratio is disposed at an upstream side of the exhaust gas and an adsorption catalyst B provided with zeolite effective for the adsorption of hydrocarbon is disposed at a downstream side of the exhaust gas.
Claims27
A catalyst system for the purification of exhaust gases from an internal combustion engine, consisting essentially of:
- (a) a catalyst A serving for the primary purification of the exhaust gases comprising a honeycomb carrier and a three-way catalyst formed thereon;
- (b) an adsorption catalyst B comprising:
- a honeycomb carrier;
- an adsorption layer formed thereon for the effective adsorption of hydrocarbons;
- and a catalyst layer comprising a noble metal selected from the group consisting of platinum, palladium and rhodium and at least one of ceria and alumina, wherein the catalyst layer is a separate layer applied to the adsorption layer and coating the adsorption layer, and wherein the adsorption catalyst B is located downstream of the catalyst A in the direction of the exhaust gas directly;
- (c) means, including a direct unbranched passageway between the catalyst A and the adsorption catalyst B, for conducting all the exhaust gas flowing out of the catalyst A to flow into the adsorption catalyst B at all time during operation of the catalyst system;
- and
- (d) means for supplying heat to the adsorption catalyst B from a heat source outside of the adsorption catalyst B, wherein the heat supplied from the heat source is supplied solely by the exhaust gases and the catalyst A.
5 more elements
A catalyst system for the purification of exhaust gases from an internal combustion engine, consisting essentially of:
- (a) a catalyst A serving for the primary purification of the exhaust gases comprising a honeycomb carrier and a three-way catalyst formed thereon;
- (b) an adsorption catalyst B comprising:
- a honeycomb carrier;
- an adsorption layer formed thereon for the effective adsorption of hydrocarbons;
- and a catalyst layer consisting essentially of a noble metal selected from the group consisting of platinum, palladium and rhodium, and at least one of ceria and alumina, wherein the catalyst layer is applied as a separate layer to the adsorption layer, and wherein the adsorption catalyst B is located downstream of the catalyst A in the direction of the exhaust gas directly;
- (c) means, including a direct unbranched passageway between the catalyst A and the adsorption catalyst B, for conducting all the exhaust gases flowing out of the catalyst A to flow into the adsorption catalyst B at all time during operation of the catalyst system;
- and
- (d) means for supplying heat to the adsorption catalyst B from a heat source outside of the adsorption catalyst B, consisting essentially of engine combustion heat carried by the exhaust gases and heat generated by reactions occurring at the catalyst A.
5 more elements
A catalyst system for the purification of exhaust gases from an internal combustion engine, consisting essentially of:
- (a) means for conducting exhaust gases from an internal combustion engine first into contact with a catalyst A comprising a honeycomb carrier and a three-way catalyst formed thereon;
- (b) means for next causing all of the exhaust gases contacted with the catalyst A to flow out of the catalyst A;
- (c) means for next causing all of the exhaust gases flowing out of the catalyst A to flow directly into an adsorption catalyst B only a single time in a single pass system, at all time during operation of the catalyst A and the adsorption catalyst B, wherein the adsorption catalyst B comprises:
- a honeycomb carrier;
- an adsorption layer formed thereon for the effective adsorption of hydrocarbons;
- and a catalyst layer consisting essentially of a noble metal selected from the group consisting of platinum, palladium and rhodium and at least one of ceria and alumina, wherein the catalyst layer is applied to the adsorption layer and is a separate layer coating the adsorption layer, and wherein the adsorption catalyst B is located downstream of the catalyst A in the direction of the exhaust gas directly;
- and
- (d) means for heating the adsorption catalyst B by a heat source for supplying heat to the adsorption catalyst B from outside of the adsorption catalyst B, the heat source consisting essentially of engine combustion heat carried by the exhaust gases and heat generated by reactions occurring at the catalyst A.
5 more elements
A catalyst system for the purification of exhaust gases from an internal combustion engine for an automobile, consisting essentially of:
- (a) means for conducting exhaust gases from an internal combustion engine first into contact with a three-way precatalyst disposed on an exhaust manifold of an engine;
- (b) means for conducting all of the exhaust gases contacted with the three-way precatalyst to directly flow into a catalyst A disposed beneath a floor of the vehicle, the catalyst A comprising a honeycomb carrier and a three-way catalyst formed thereon;
- (c) means for next causing all of the exhaust gases contacted with the catalyst A to flow out of the catalyst A;
- (d) means for next causing all of the exhaust gases flowing out of the catalyst A to flow directly into an adsorption catalyst B only a single time in a single pass system, at all time during operation of the catalyst A and the adsorption catalyst B, wherein the hydrocarbons are effectively adsorbed;
- and a catalyst layer consisting essentially of a noble metal selected from the group consisting of platinum, palladium and rhodium and at least one of ceria and alumina, wherein the adsorption catalyst B is located downstream of the catalyst A in the direction of the exhaust gas directly, and wherein the adsorption catalyst B is disposed beneath the floor of the vehicle;
- and
- (e) means for heating the adsorption catalyst B by a heat source for supplying heat to the adsorption catalyst B from outside of the adsorption catalyst B, the heat source consisting essentially of engine combustion heat carried by the exhaust gases and heat generated by reactions occurring both at the three-way precatalyst and catalyst A.
4 more elements
Dependencies are inferred from the claim text.