Internal Combustion Engine Control Device and Internal Combustion Engine Control Method

An internal combustion engine control method comprising:

• a correlation index estimating process of estimating, by an internal combustion engine control device, a piston temperature correlation index correlated with a temperature of a piston based on an operating condition parameter and an oil jet parameter for injecting oil to a back surface of the piston;
• and
• a hydraulic pressure setting process of setting, by the internal combustion engine control device, a hydraulic pressure of an oil jet based on the piston temperature correlation index and an evaporation parameter of fuel attached to the piston,
• wherein in the hydraulic pressure setting process, when the piston temperature correlation index is less than a first predetermined value determined based on a temperature corresponding to a fuel evaporable condition as the evaporation parameter, the hydraulic pressure of the oil jet is set to a hydraulic pressure at which oil jet injection is stoppable.