Patent ID: 7444254
Filing Date: 2008-10-28
Classification: F01L

Abstract:
1. A valve timing control apparatus for an internal combustion engine, comprising: a driving rotator adapted to be rotated by a torque outputted from the internal combustion engine; a driven rotator arranged to rotate with a relative rotational phase with respect to the driving rotator and adapted to transmit the torque from the driving rotator to a camshaft of the internal combustion engine via a torque transmission path; a camshaft-torque actuation mechanism including at least a pair of camshaft-torque actuation chambers arranged in the torque transmission path, the camshaft-torque actuation mechanism being configured to alter the relative rotational phase by providing at least a state allowing a unidirectional flow of working fluid from one of the camshaft-torque actuation chambers to another of the camshaft-torque actuation chambers; and a hydraulic actuation mechanism including at least a pair of hydraulic actuation chambers arranged in the torque transmission path, the hydraulic actuation mechanism being configured to alter the relative rotational phase at least by supplying and draining working fluid to and from one of the hydraulic actuation chambers, a first rate of alteration with respect to alteration in the relative rotational phase, at which the hydraulic actuation chambers alter in volumetric capacity in accordance with the alteration in the relative rotational phase, being higher than a second rate of alteration with respect to the alteration in the relative rotational phase, at which the camshaft-torque actuation chambers alter in volumetric capacity in accordance with the alteration in the relative rotational phase.