Control device for internal combustion engine and control method for internal combustion engine

A control method for an internal combustion engine, the internal combustion engine including a memory configured to store a program, and at least one processor configured to execute the program, the control method comprising:

• executing, by the at least one processor, a manipulated variable decision process of deciding a manipulated variable of the internal combustion engine from a control input value related to a controlled variable including a stochastic dispersion, in accordance with a predetermined conversion rule;
• executing, by the at least one processor, a sample value calculation process of calculating a sample value of the controlled variable for each sampling cycle based on information from a sensor that detects a state of the internal combustion engine;
• executing, by the at least one processor, an expectation value calculation process of calculating a reference expectation value of the controlled variable from the control input value using a normative model for the internal combustion engine;
• executing, by the at least one processor, a hypothesis test process of performing a hypothesis test for a null hypothesis that an average value of a predetermined number of recent sample values of sample values of the controlled variable is equal to the reference expectation value;
• and
• executing, by the at least one processor, an adaptive control process of modifying the predetermined conversion rule by an adaptive control based on an error between the average value and the reference expectation value when the null hypothesis is rejected.