摘要 |
A valve timing control apparatus is adapted to an exhaust valve side of an internal combustion engine. A vane member is arranged to rotate with a camshaft relative to a timing sprocket member. The vane member is rotated at low speed engine operation dominantly by a camshaft-torque actuation mechanism and at high speed engine operation dominantly by a hydraulic actuation mechanism. The camshaft-torque actuation mechanism is actuated by an alternating torque of the camshaft, whereas the hydraulic actuation mechanism is actuated by a fluid pump. The vane member includes a first vane arranged to operate in the camshaft-torque actuation mechanism and a second vane arranged to operate in the hydraulic actuation mechanism. The first vane has a shorter radial length and a smaller pressure-receiving area than the second vane.
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