Patent ID: 8808630

Claim:
A method for operating an exhaust gas catalytic converter configured to reduce nitrogen oxides contained in an exhaust gas flow by a urea-containing solution which reacts in the exhaust gas flow to form at least ammonia, the method comprising: introducing an amount of the urea-containing solution upstream of the exhaust gas catalytic converter as far as an ammonia slip through the exhaust gas catalytic converter; determining a first actual value of the loading state of the exhaust gas catalytic converter with ammonia at the time of the slip; determining a first estimated value of the loading state at the time of the slip using a dynamic model for the loading; subsequently emptying the ammonia from the exhaust gas catalytic converter; determining a second actual value of the loading state of the exhaust gas catalytic converter with ammonia when the exhaust gas catalytic converter is emptied as predefined; determining a second estimated value of the loading state using the dynamic model for the loading when the exhaust gas catalytic converter is emptied; and adapting at least one parameter of the dynamic model as a function of the two actual values and of the two estimated values.