| 摘要 |
A two-step valve lifter for actuation of a valve member in an internal combustion engine includes an outer cam follower, having a cam-engaging upper surface with a cylindrical body depending therefrom, and an inner cam follower disposed within said cylindrical body. The inner follower includes a hollow cylinder having a first diameter "D", an upper, closed end and a lower, open end. The open end is configured to receive, for disposition between the two-step valve lifter and the valve member, a lash adjusting, hydraulic element assembly. An obround follower foot, having a length "L" normal to said camshaft axis and a width "W" parallel to said camshaft axis and less than said length "L", extends from the upper, closed end of the inner follower to terminate in a cam engaging surface which is extendable through an opening in the cam engaging surface of the outer cam follower. The width "W" of the follower foot is less than the first diameter "D" of the hollow cylinder of the inner follower. In operation, the first cam is operable in a first mode to contact the cam engaging surface of the obround follower foot and in a second mode of operation the second cam is operable in a second mode of operation to contact the cam engaging surface of the outer cam follower at a location radially inwardly of the first diameter of the hollow cylinder of the inner cam follower.
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