Patent ID: 7007645

Claim:
A method for controlling continuously controlling valve timing of a vehicle engine, comprising: determining if an engine has been cold-started; if it is determined that the engine has been cold-started calculating an estimated oil temperature on the basis of a coolant temperature at starting of the engine and a period of time that has elapsed after the starting of the engine; storing the estimated oil temperature in a memory; controlling the continuously controlling valve timing based on the estimated oil temperature; if it is determined that the engine has not been cold-started, detecting a current coolant temperature; and determining if a difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than a predetermined difference, wherein the controlling of the continuously controlling valve timing based on an energizing time calculated from the estimated oil temperature is executed when the difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than the predetermined difference.