For an internal combustion engine with a common rail system including individual accumulators, a process for open- and closed-loop control is proposed, in which the individual accumulator pressure (pE) is detected within a measuring interval and stored, an absolute minimum value of the stored individual accumulator pressure (pE) is interpreted as the end of the main injection, and on the basis of the end of the main injection, a mathematical function is used to calculate a virtual starting time for the main injection. In the measuring interval after the end of the main injection, the individual accumulator pressure (pE) is filtered within a time window, a local minimum value of the filtered individual accumulator pressure is interpreted as the end of a post-injection, and a mathematical function is used to calculate a virtual start of the post-injection.