Method for determining the aging of an oxidation catalyst in an exhaust gas aftertreatment system of an internal combustion engine, method for detecting ash in a particle filter of an exhaust gas aftertreatment system, control device, and internal combustion engine

1. A method for determining aging of an oxidation catalyst in an exhaust gas aftertreatment system of an internal combustion engine, comprising the steps of:

obtaining a soot burn-off rate of a particle filter of the exhaust gas aftertreatment system;

adapting a function, having at least one adaptation parameter, to the soot burn-off rate in dependence on at least one variable for which a value of the adaptation parameter is dependent on aging of the oxidation catalyst;

determining the aging of the oxidation catalyst based on the value of the adaptation parameter which is obtained by adapting the function;

replacing the oxidation catalyst when the aging reaches a predefined level;

evaluating a development of the soot burn-off rate over time; and

performing error detection using the development of the soot burn-off rate over time.

2. The method according to claim 1 , including determining the aging of the oxidation catalyst by comparing the at least one adaptation parameter with at least one previously determined characteristic value.

3. The method according to claim 1 , including adapting the function to the soot burn-off rate in dependence on a temperature of the particle filter and a nitrogen oxide concentration in the exhaust gas.

4. The method according to claim 1 , including adapting a linear function, a second degree polynomial or a third degree polynomial to the soot burn-off rate.

5. The method according to claim 1 , wherein the soot burn-off rate is obtained by the following steps:

obtaining a differential pressure that drops across the particle filter;

obtaining a load of the particle filter from the differential pressure using a loading model;

obtaining a soot input into the particle filter, and

obtaining the soot burn-off rate from the load and the soot input.

6. The method according to claim 5 , including obtaining the soot burn-off rate using a Kalman filter.

7. The method according to claim 1 , including evaluating the development of the at least one adaptation parameter over time.

8. A method for detecting ash in a particle filter of an exhaust gas aftertreatment system, comprising the steps of:

detecting a differential pressure that drops across the particle filter;

determining aging of an oxidation catalyst of the exhaust gas aftertreatment system by obtaining a soot burn-off rate of a particle filter of the exhaust gas aftertreatment system;

adapting a function, having at least one adaptation parameter, to the soot burn-off rate in dependence on at least one variable for which a value of the adaptation parameter is dependent on aging of the oxidation catalyst;

determining the aging of the oxidation catalyst based on the value of the adaptation parameter which is obtained by adapting the function;

replacing the oxidation catalyst when the aging reaches a predefined level;

adapting a loading model to the aging of the oxidation catalyst;

determining a load of the particle filter using the adapted loading model; and

determining depositing of ash on the particle filter from the load and the differential pressure.

9. The method according to claim 8 , including adapting the loading model to the depositing of ash on the particle filter.

10. The method according to claim 8 , including initializing the method with an initial value for a depositing of ash on the particle filter.

11. The method according to claim 8 , wherein the method is carried out iteratively.

12. A control device for an internal combustion engine, the control device being configured to carry out a method comprising the steps of:

obtaining a soot burn-off rate of a particle filter of the exhaust gas aftertreatment system;

adapting a function, having at least one adaptation parameter, to the soot burn-off rate in dependence on at least one variable for which a value of the adaptation parameter is dependent on aging of the oxidation catalyst;

determining the aging of the oxidation catalyst based on the value of the adaptation parameter which is obtained by adapting the function;

replacing the oxidation catalyst when the aging reaches a predefined level;

evaluating a development of the soot burn-off rate over time; and

performing error detection using the development of the soot burn-off rate over time.

13. An internal combustion engine, comprising: an exhaust gas aftertreatment system having an oxidation catalyst; and a control device according to claim 12 .

14. A control device for an internal combustion engine, the control device being configured to carry out a method comprising the steps of:

detecting a differential pressure that drops across the particle filter;

determining aging of an oxidation catalyst of the exhaust gas aftertreatment system by obtaining a soot burn-off rate of a particle filter of the exhaust gas aftertreatment system;

adapting a function, having at least one adaptation parameter, to the soot burn-off rate in dependence on at least one variable for which a value of the adaptation parameter is dependent on aging of the oxidation catalyst;

determining the aging of the oxidation catalyst based on the value of the adaptation parameter which is obtained by adapting the function;

replacing the oxidation catalyst when the aging reaches a predefined level;

adapting a loading model to the aging of the oxidation catalyst;

determining a load of the particle filter using the adapted loading model; and

determining depositing of ash on the particle filter from the load and the differential pressure.

15. An internal combustion engine, comprising: an exhaust gas aftertreatment system having an oxidation catalyst; and a control device according to claim 14 .