Method and control device for detecting, during the operation of a hybrid vehicle, whether combustion is taking place in an internal combustion engine of the hybrid vehicle

A method to detect whether combustion is taking place in an internal combustion engine of a hybrid vehicle during operation of the hybrid vehicle, whereby a decoupler is provided between the internal combustion engine and an electric machine that serves to power the hybrid vehicle, and whereby a speed sensor is provided between the internal combustion engine and the decoupler, comprising:

• determining, according to a passive diagnosis during which the decoupler is closed, whether there is an indication that combustion is absent in the internal combustion engine by analyzing, using the speed sensor, a rotational speed of the internal combustion engine as a function of a crankshaft angle,
• when, according to the passive diagnosis, it is determined that no combustion is taking place in the internal combustion engine:
• opening the decoupler between the internal combustion engine and the electric machine;
• stopping fuel injection and mass flow into the internal combustion engine after the decoupler has been opened, and restarting the internal combustion engine while the decoupler is still open;
• after the internal combustion engine has been restarted and while the decoupler is still open,
• receiving a speed signal from the speed sensor when the decoupler is open, said speed signal indicating a rotational speed of the internal combustion engine when the decoupler is open;
• and
• determining, on the basis of the speed signal when the decoupler is open, whether combustion is taking place in the internal combustion engine.