Internal combustion engine control system

A vehicle-supervising electronic control unit (VS-ECU) (61) measures driving torque, which is outputted from an engine (11) to a drive shaft (15) through an automatic transmission (13). The VS-ECU (61) measures road surface transmission torque based on rotation speeds of driving wheels (19RL, 19RR) of a vehicle, vehicle body speed and driving wheel torque, which are measured in advance. The VS-ECU (61) compares the driving torque with the road surface transmission torque. If it is determined that the driving torque is greater than the road surface transmission torque, the VS-ECU (61) estimates an opening degree of an air bypass valve (79) for controlling the driving torque so that a difference between the driving torque and the road surface transmission torque is decreased.