Method for determining the compression of an internal combustion engine

A method for operating an internal combustion engine wherein the compression can be variably adjusted by means of an actuator depending on an actuating variable, the method comprising:

• determining a value for a sensor signal indicative of a compression of the internal combustion engine;
• checking the plausibility of the sensor signal by:
• ascertaining a series of corresponding values of the sensor signal and values of the actuating variable;
• determining a mathematical relationship between the sensor signal and the actuating variable based on the ascertained series of corresponding values of the sensor signal and of the actuating variable;
• determining a deviation between the determined relationship and a predetermined characteristic relationship between the sensor signal and the actuating variable;
• and
• determining that the sensor signal is plausible when the determined deviation is lower than a predetermined threshold value;
• and
• if the determined deviation is higher than the predetermined threshold value, adjusting operation of the internal combustion engine.