An internal combustion engine has a variable valve timing apparatus
including a driving motor between a crankshaft and a camshaft. The
driving motor rotates synchronously with the camshaft when the valve
timing apparatus is not in operation. A motor rotation sensor produces a
motor rotation signal. When the engine rotation speed is below a
reference speed, the driving motor is not energized. Under this
condition, the rotation speed and the rotation direction of the engine
are calculated based on the motor rotation signal in place of a crank
rotation signal produced by a crank angle sensor. Further, the rotation
stop position of the engine is calculated based on the motor rotation
signal when the engine is stopped.