Control device and control method for internal combustion engine

A control device for an internal combustion engine including an upstream cleaning device and a downstream cleaning device that are provided in an exhaust gas passage and a temperature sensor configured to detect a temperature of exhaust gas between the upstream cleaning device and the downstream cleaning device, the control device comprising:

• a processor configured to
• estimate a temperature of the downstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor;
• estimate a temperature of the upstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor;
• and
• in response to (i) the estimated temperature of the upstream cleaning device being equal to or higher than a predetermined first lower-limit temperature and (ii) the estimated temperature of the downstream cleaning device being equal to or higher than a predetermined second lower-limit temperature, perform an abnormality determining process for the upstream cleaning device,
• wherein the processor is configured to estimate the temperature of the downstream cleaning device and the temperature of the upstream cleaning device based on a temperature of exhaust gas flowing out of an exhaust port of the internal combustion engine, an amount of heat transmitted between exhaust gas and an exhaust pipe, and an amount of heat discharged from the exhaust pipe.