The present invention relates to a method for adaption of an exhaust treatment system arranged for treating an exhaust stream produced by an engine, where the exhaust treatment system includes at least a first additive dosage device, a first selective catalytic reduction catalyst arranged downstream of the first additive dosage device, a second additive dosage device arranged downstream of the first selective catalytic reduction catalyst, and a second selective catalytic reduction catalyst arranged downstream of the second additive dosage device. The method includes initiating an adaption of the second selective catalytic reduction catalyst, and controlling, during the adaption of the second selective catalytic reduction catalyst, the first additive dosage device to inject additive in accordance with at least one injection rule being designed for the adaption.

An object of the present invention is to increase the reduction performance of nitrogen oxides compared to existing three-way catalysts; simultaneously inhibit the emission of ammonia and nitrous oxide; simplify a process by means of a method of further doping an iridium-ruthenium catalyst into a commercial three-way catalyst; and expand the scope of application. The present invention provides a catalyst for simultaneously inhibiting the emission of ammonia and nitrous oxide by doping an iridium-ruthenium catalyst component into a three-way catalyst (TWC), a diesel oxidation catalyst, or a lean NOx trap supported on a honeycomb support.

Disclosed is a method for diagnosing a first exhaust treatment component for treatment of an exhaust gas stream comprising means for oxidizing nitric oxide into nitrogen dioxide. A first reduction catalytic converter is arranged upstream said means for oxidizing nitric oxide into nitrogen dioxide, and a second reduction catalytic converter is arranged downstream said means. A reagent is for reduction of nitrogen oxides in said first catalytic converter, and a first sensor measures an occurrence of nitrogen oxide downstream said means but upstream said second reduction catalytic converter. The method comprises: causing a supply of reagent upstream said first reduction catalytic converter to an extent exceeding the extent to which reagent is consumed by the first reduction catalytic converter, determining a first measure of the occurrence of reagent downstream said means for oxidizing, and diagnosing said means for oxidizing nitric oxide into nitrogen dioxide based on said first measure.

An exhaust gas system for an internal combustion engine includes at least one component which delimits an exhaust gas flow volume via an outer wall and, on an inner side of the outer wall which faces the exhaust gas flow volume, supports at least one shielding element. An intermediate space is formed between the outer wall and the shielding element. At least one connecting molding on the shielding element is directed toward the outer wall and is connected fixedly to the outer wall.

A control device is applied to an internal combustion engine equipped with an electric heating catalyst system provided with an EHC. The control device executes a preheating process to warm up an exhaust gas reduction catalyst prior to a start of the internal combustion engine by supplying electric power to the EHC, when the control device determines that a temperature of the exhaust gas reduction catalyst is lower than an activation temperature. The control device executes a determination process for determining whether water is adhered to a catalyst carrier. The control device starts the internal combustion engine without executing the preheating process when the control device determines by the determination process that water is adhered to the catalyst carrier, even when the control device determines that the temperature of the exhaust gas reduction catalyst is lower than the activation temperature.

An aftertreatment system comprises a housing defining a first and a second internal volume fluidly isolated from each other. A first aftertreatment leg extends from the first to the second internal volume and includes an oxidation catalyst and a filter. The oxidation catalyst receives exhaust gas from an inlet conduit and the filter emits exhaust gas into the second internal volume. A second aftertreatment leg extends from the second to the first internal volume and includes at least one SCR catalyst disposed offset from the first aftertreatment leg. A decomposition tube is disposed offset from the SCR catalyst and the oxidation catalyst. The decomposition tube is configured to receive the exhaust gas from the second internal volume and communicate it to the inlet of the at least one SCR catalyst. A reductant injection inlet is defined proximate to the inlet of the decomposition tube for reductant insertion.

Disclosed is a method for diagnosing a first exhaust treatment component for treatment of an exhaust gas stream comprising means for oxidizing nitric oxide into nitrogen dioxide. A first reduction catalytic converter is arranged upstream said means for oxidizing nitric oxide into nitrogen dioxide, and a second reduction catalytic converter is arranged downstream said means. A reagent is for reduction of nitrogen oxides in said first catalytic converter, and a first sensor measures an occurrence of nitrogen oxide downstream said means but upstream said second reduction catalytic converter. The method comprises: causing a supply of reagent upstream said first reduction catalytic converter to an extent exceeding the extent to which reagent is consumed by the first reduction catalytic converter, determining a first measure of the occurrence of reagent downstream said means for oxidizing, and diagnosing said means for oxidizing nitric oxide into nitrogen dioxide based on said first measure.

When a catalyst temperature of a catalyst device is at or below a lower limit air-fuel ratio richness control is prohibited. When a first timing, where an estimated value of a NOx storage amount has reached an enrichment start threshold value, and a second timing, based on a set interval time in an enrichment interval time map, are both satisfied, the control is started. The second timing is corrected by multiplying the set interval time by an enrichment interval correction coefficient preset based on the catalyst temperature and a storage ratio of the estimated value of the NOx storage amount to an enrichment start threshold value of the NOx storage amount. The frequency of the air-fuel ratio richness control of a catalyst device configured to recover a purification capacity of a catalyst is reduced, and the catalyst temperature is raised while preventing white smoke development and hydrocarbon slip, to thereby achieve improvement in exhaust gas composition and improvement in fuel efficiency.

The present invention provides a carbon dioxide reduction catalyst that is used in reduction reactions of carbon dioxide and that has high methanol selectivity. A carbon dioxide reduction catalyst according to the present invention is used in producing methanol by reduction reactions of carbon dioxide, and contains Au and Cu as catalyst components and ZnO as a carrier. It is preferable that the catalyst components contain 7-25 mol % of Au as a catalyst component. This makes it possible to obtain high methanol selectivity—for example, selectivity of not less than 80%. The carbon dioxide reduction catalyst makes it possible to obtain high methanol selectivity even under the conditions of not more than 240° C. and not more than 50 bar.

The present invention provide a method for purifying exhaust gas in which nitrogen oxides (NOx) gas is removed from a combustion exhaust gas. The method for purifying exhaust gas according to the invention is characterized in that water vapor is further added to raw exhaust gas to be processed to increase the water vapor concentration in the exhaust gas and the resulting moisture-adjusted exhaust gas is introduced into a denitration catalyst layer. The water vapor concentration in the moisture-adjusted exhaust gas is preferably 22.0% by volume or less in the total of the water vapor originally contained in the raw exhaust gas and the added water vapor.