Temperature estimation device for friction engaging element

A temperature estimation device for a plurality of friction engaging elements that are applied to a vehicle provided with a transmission, the plurality of friction engaging elements operating with hydraulic pressure, the temperature estimation device estimating a temperature of the plurality of friction engaging elements at a time of shifting of the transmission, the temperature estimation device comprising:

• a storage device configured to store mapping data that defines a mapping, the mapping including:
• as an input variable:
• a heat amount variable indicating an amount of heat generated by the plurality of friction engaging elements during the shifting of the transmission, the heat amount variable including:
• a speed variable indicating a relative rotation speed of members of the plurality of friction engaging elements that rotate relative to each other during the shifting of the transmission, and
• a hydraulic pressure variable indicating the hydraulic pressure supplied to the friction engaging elements during the shifting of the transmission, and
• a shifting variable indicating the plurality of friction engaging elements to be engaged at the time of the shifting of the transmission;
• and
• as an output variable:
• the temperature of the plurality of friction engaging elements at a time of shifting the transmission;
• and
• an execution device configured to execute an acquisition process of acquiring a value of the input variable and a calculation process of inputting the value of the input variable acquired by the acquisition process into the mapping to calculate a value of the output variable.