Patent ID: 7765798

Claim:
A method for reducing the nitrogen oxide proportion in the exhaust gas of an internal combustion engine, the method comprising the following steps: carrying out a selective catalytic reduction at a reduction catalytic converter by providing a reducing agent at least in a discontinuous manner; determining a quantity of the reducing agent to be provided by taking into consideration a storage capacity of the reduction catalytic converter for the reducing agent and a dependency of the storage capacity on a temperature of the reduction catalytic converter; determining the temperature of the reduction catalytic converter in at least one of the following ways: measuring the temperature of the reduction catalytic converter; or calculating the temperature of the reduction catalytic converter; taking at least one of the following items of information into consideration in the calculation of the temperature of the reduction catalytic converter: a measured temperature upstream of the reduction catalytic converter; a measured temperature downstream of the reduction catalytic converter; present operating data of the internal combustion engine; operating data of the internal combustion engine from the past; a regeneration behavior of a particle separator; or a loading of a particle separator; and carrying out a regeneration of the particle separator if the quantity of the reducing agent stored in the reduction catalytic converter is less than or equal to a storage capacity at a maximum temperature, generated by the regeneration, in the reduction catalytic converter.