Robert Boschgmbh

Herbert Schoemig

Tobias Pfister

Stefan Scherer

Cornelia Nagel

Andreas Eckert

Holger Ziegler

A method () for determining an amount of hydrocarbons in an exhaust gas () downstream of a lean-operation internal-combustion engine (), comprising the following steps: observing a first catalyst heating mode of the internal-combustion engine () at a high catalyst temperature, wherein a predefinable amount of fuel having a predominantly non-combusting portion is introduced into a combustion chamber of the internal-combustion engine (); determining an actual temperature change downstream of an oxidation catalyst () downstream of the internal-combustion engine () during the first catalyst heating mode; and determining the amount of hydrocarbons (cHC) in the exhaust gas () upstream of the oxidation catalyst () based on the actual temperature change. Furthermore, a computing unit () and a computer program for carrying out such a method () are proposed.

Method, computing unit, and computer program for determining an amount of hydrocarbons in an exhaust gas of a lean-operation internal-combustion engine

A method for monitoring a nitrogen oxide storage catalyst in an exhaust system of an internal combustion engine, in which a reduction of nitrogen oxides is carried out by means of a reducing agent is disclosed. During a regeneration of the nitrogen oxide storage catalyst, the following steps are carried out: A measurement is carried out, from which a slip rate of the reducing agent not absorbed in the nitrogen oxide storage catalyst is ascertained. In addition, at least one expected value for the slip rate of the reducing agent is ascertained from at least one model. Subsequently, a computation of a monitoring variable is carried out by means of the slip rate of the reducing agent ascertained from the measurement and the at least one expected value for the slip rate of the reducing agent. Finally, a diagnosis of the storage capacity of the nitrogen oxide storage catalyst is carried out on the basis of the monitoring variable.

Method for monitoring a nitrogen oxide storage catalyst

The present invention relates to a method for operating an exhaust gas aftertreatment apparatus () of an internal combustion engine (), which comprises an oxidation catalytic converter (), an SCR catalytic converter () and a first temperature sensor () disposed in the direction of flow downstream of the oxidation catalytic converter () and upstream of the SCR catalytic converter (), an exhaust gas atmosphere capable of exothermal reaction in said oxidation catalytic converter () being generated by the metering of hydrocarbons into the exhaust gas () upstream of said oxidation catalytic converter () during a heating operation. The method is thereby characterized in that a first numerical measurement value of a nominal value of a hydrocarbon conversion in said oxidation catalytic converter () is formed, in that a second numerical measurement value of an actual value of the hydrocarbon conversion in said oxidation catalytic converter () is determined as a function of the signals of the first temperature sensor (), in that the second numerical measurement value is compared with the first numerical measurement value and in that the metering of the hydrocarbons is reduced if said second numerical measurement value is smaller than said first numerical measurement value. An independent claim relates to a control device set up for carrying out the method.

Method for operating an exhaust gas aftertreatment apparatus

A method for monitoring a nitrogen oxide storage catalytic converter (NSC) in the exhaust gas duct of an internal combustion engine which is operated at least temporarily in a lean fashion, wherein during a lean mode of the internal combustion engine nitrogen oxides from the exhaust gas are stored by the nitrogen oxide storage catalytic converter, wherein during a regeneration phase of the nitrogen oxide storage catalytic converter the internal combustion engine is operated in a rich fashion, and as a result the nitrogen oxides stored in the nitrogen oxide storage catalytic converter are removed, and wherein an exhaust gas component or exhaust gas characteristic variable which is characteristic of the profile of the regeneration is detected during the regeneration phase by means of an exhaust gas probe.

Method and device for monitoring a nitrogen oxide storage catalytic converter

A process for monitoring a conversion capacity of a particulate filter arranged in an exhaust gas duct of an internal combustion engine to oxidize nitrogen monoxide to nitrogen dioxide over a catalytic coating includes determining a flow resistance of the particulate filter and setting a temperature of the exhaust gas upstream of the particulate filter. A threshold for a change in the flow resistance of the particulate filter is defined. The monitoring process determines that inadequate conversion capacity of the catalytic coating of the particulate filter is reached when a change in the flow resistance of the particulate filter does not reach the defined threshold within a given period of time.

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Stuttgart, Germany

Herbert Schoemig