Patent ID: 8341942

Claim:
A device for providing ammonia for the selective catalytic reduction of nitrogen oxides in the exhaust system of an internal combustion engine, the device comprising: a device for determining at least one of the following variables: i) a present actual state of the internal combustion engine, or ii) at least one actuating variable for influencing the state of the internal combustion engine; a control device configured for calculating a possible nitrogen oxide emission of the internal combustion engine on a basis of an evaluation of at least one measured variable taking into consideration at least one previous value of at least one of the at least one measured variables and for calculating an ammonia quantity corresponding to a possible nitrogen oxide emission; said control device configured to extrapolate to a future nitrogen oxide emission, calculate a change in the state of the internal combustion engine on a basis of a change in the at least one actuating variable and take a probability of different possible changes in the state of the internal combustion engine, from an actual state to possible nominal states, into consideration; and a device for providing an ammonia quantity, said device for providing an ammonia quantity including an evaporator disposed outside the exhaust gas for evaporating a urea-water solution, a hydrolysis catalytic converter disposed outside the exhaust gas, and a device for supplying the urea-water solution to said evaporator.