Patent ID: 8200412

Claim:
A controller for an internal combustion engine applied to a system in which a main fuel including alcohol and an auxiliary fuel of which volatility is higher than the main fuel can be supplied, the controller comprising: an alcohol concentration obtaining means for detecting or estimating the alcohol concentration of the main fuel; a coolant temperature sensor detecting a coolant temperature of the internal combustion engine; and an auxiliary fuel supply control means having a program, which when executed causes the fuel supply control means to control an auxiliary fuel supply based on the coolant temperature detected by the coolant temperature sensor and alcohol concentration of the main fuel detected or estimated by the alcohol concentration obtaining means; wherein in a case that the coolant temperature sensor is abnormal, the auxiliary fuel supply control means conducts the auxiliary fuel supply when the alcohol concentration of the main fuel detected or estimated by the alcohol concentration obtaining means is greater than or equal to an auxiliary fuel supply determination value.