u201c ready u201d state 3 1 and the engine switches to u201c start phase u201d state 3 2 alternatively if the ignition is turned off during u201c ready u201d state 3 1 no transition to the u201c start phase u201d state but to u201c coast u201d state 3 5 takes place u201c start phase u201d state 3 2 is used for making the engine bring itself to run if this cannot be done i e if the engine stalls which means that the rotational speed of the engine remains below a predefinable threshold value thr 1 for a certain minimum period of time the system jumps back to u201c ready u201d state 3 1 in contrast if the start phase is successfully completed i e the rotational speed of the engine exceeds a predefinable second threshold value thr 2 state machine 12 transitions within second layer n 2 from operating state u201c start u201d 2 8 to operating state u201c normal operation u201d 2 9 more precisely after the start phase the engine first transitions into an u201c idle u201d state 3 3 in third layer n 3 of the state machine as illustrated in fig2 depending on the intent of the driver of a vehicle in which the engine is installed or depending on the driving situation the operating state of the engine changes during u201c normal operation u201d state 2 9 between the sub states u201c idle u201d 3 3 and u201c accelerate u201d 3 4 if engine 20 stalls while it is in.