Patent ID: 6382155
Filing Date: 2002-05-07
Classification: F01L

Abstract:
In an internal combustion engine, a variable camshaft timing system comprising:a camshaft (36) having a central axis, said camshaft being rotatable about said central axis; a vane (26) having at least one lobe (22,24 or 26) secured to the camshaft for rotation therewith, said vane being nonoscillatable with respect to the camshaft; an annular housing (28) surrounding the vane and having at least one recess (30, 32, or 34), the at least one recess having a circumferential extent grater than the circumferential extent of the at least one lobe and receiving the at least one lobe, said annular housing being rotatable with said camshaft and said vane and being oscillatable with respect to said camshaft and said vane; hydraulic means (56, 58, 68) for causing relative circumferential motion between said housing and said vane; and locking means reactive to hydraulic pressure and movable along said central axis for preventing relative circumferential motion between said housing and said vane at one of a plurality of relative circumferential positions of said housing and said vane during periods of low hydraulic pressure and for permitting said relative motion during periods of higher hydraulic pressure.