VARIABLE VALVE OPERATION TIMING CONTROL DEVICE

A spool valve for controlling the valve operation timing of an Internal combustion engine has its spool moved in accordance with an output duty Td so that an actual relative rotational angle .theta. may approach the target relative rotational angle .theta.a which is determined in accordance with the operating conditions of the engine. Here, the output duty Td is a sum of a learning ignition advance duty Ta and a temperature correcting duty Tthw. When the output duty Td is outputted, the spool is moved to a position where an oil pressure passage starts to be opened. From this position, the spool is further moved toward an ignition advance by the duty according to a deviation (.theta.a-.theta.). When the relative rotational angle .theta. approaches the angle .theta.a, a learning holding duty Th is outputted in place of the duty Ta so that the spool is controlled to a position where the oil pressure passage is closed. Incidentally, in case of movement toward an ignition lag, a learning ignition lag angle duty Tr is outputted in place of the duty Ta.