Method for Operating an Internal Combustion Engine

A method for operating an air-compressing fuel-injection internal combustion engine having an exhaust gas post-treatment system that includes a particle filter and a nitrogen oxide reduction catalytic converter, said method comprising:

• providing for a plurality of internal combustion engine operating settings with respective predefined values for predefined internal combustion engine operating parameters;
• when the internal combustion engine is warming up, setting a heating operating setting;
• when the heating operating setting is active and the temperature in the exhaust gas post-treatment system exceeds a predefinable second threshold value, activating a separate fuel post-injection;
• and
• when the temperature in the exhaust gas post-treatment system exceeds a predefinable first threshold value that is higher than the second threshold value, and the internal combustion engine is in a warmed-up state, changing from the heating operating setting to a basic operating setting and enabling addition of a reducing agent into the exhaust gas post-treatment system downstream of the particle filter and upstream of the nitrogen oxide reduction catalytic converter.