Patent ID: 6968817
Filing Date: 2005-11-29
Classification: F01L,F02D,Y02T

Abstract:
1. A controller for controlling a valve timing of an internal combustion engine, the internal combustion engine including a crankshaft and a camshaft, the controller comprising: a variable mechanism including a rotor, rotated synchronously with the crankshaft, and an advance pressure chamber and a delay pressure chamber, which are defined between the rotor and the camshaft and which accommodate a fluid, the variable mechanism changing the rotational phase of the camshaft relative to the rotor in accordance with the difference between the pressure of the fluid in the advance pressure chamber and the pressure of the fluid in the delay pressure chamber so as to vary the valve timing, the pressure difference being set by a variable command value; a lock mechanism including a projection, arranged on either one of the rotor and the camshaft, and a recess, arranged on the other one of the rotor and the camshaft, the lock mechanism engaging the projection with the recess when the rotational phase of the camshaft matches a predetermined lock phase to lock relative rotation of the camshaft relative to the rotor, wherein the variable mechanism enters a most easily unlocking fluid pressure state when the command value is set to an unlocking command value; and a command value setting means for gradually increasing or decreasing the command value from a first predetermined value to the unlocking command value and then to a second predetermined value so as to unlock the relative rotation of the camshaft.