Control device for internal combustion engine and method of estimating combustion chamber-wall temperature of internal combustion engine

A method of estimating a combustion chamber-wall temperature of an internal combustion engine, the method comprising:

• a step of measuring a cooling water temperature of an internal combustion engine;
• a step of measuring an intake air amount of the internal combustion engine;
• a step of estimating a wall temperature of a combustion chamber during a combustion operation of the internal combustion engine;
• a step of performing fuel-cut for stopping supply of fuel to the combustion chamber in a deceleration operation of the internal combustion engine;
• a step of obtaining a difference between an estimated value of the wall temperature of the combustion chamber at the time of start of the fuel-cut and the cooling water temperature;
• a step of obtaining an integrated value of the intake air amount after the start of the fuel-cut;
• a step of reducing data of the difference according to an increase in the integrated value;
• and
• a step of obtaining an estimated value of the wall temperature of the combustion chamber during the fuel-cut based on a measured value of the cooling water temperature and the data of the difference.