Multi-mode valve control mechanism for cam-driven poppet valves

1. A multi-mode valve control mechanism for an engine, comprising:

a primary cam follower rotatably mounted within a mount and having one end engaging a camshaft;

one or more secondary cam followers rotatably mounted within a mount and having one end engaging the camshaft, each secondary follower including means for coupling and decoupling to the primary cam follower;

a shaft operably coupled to the mount for each of the one or more secondary cam followers; and

a spring disposed about the shaft and positioned between the mount and a seat for exerting a biasing force on the secondary cam followers,

wherein, in a first mode of operation, the primary cam follower is not operatively coupled to the one or more secondary cam followers in such a way that actuation of the one or more secondary cam followers will not actuate the primary cam follower, and

wherein, in a second mode of operation, the primary cam follower is operatively coupled to the one or more secondary cam followers in such a way that actuation of the one or more secondary cam followers will also actuate the primary cam follower.

2. The control mechanism according to claim 1 , wherein the coupling and decoupling means comprises a locking pin that is capable of being disposed within a cavity of the shaft.

3. The control mechanism according to claim 1 , wherein the coupling and decoupling means comprises blocking a weep hole in fluid communication with a cavity of the shaft.

4. A multi-mode valve coupling mechanism for an engine, comprising:

a primary cam follower rotatably mounted within a mount and having one end engaging a camshaft;

one or more secondary cam followers rotatably mounted within the mount and having one end engaging the camshaft, each secondary cam follower operatively coupled to a shaft;

a shaft operably coupled to the mount for each of the one or more secondary cam followers; and

a biasing member disposed about the shaft and positioned between the mount and a seat for exerting a biasing force therebetween,

wherein a frequency and a duration at which valves in a valve train are actuated is changed by activating only the primary cam follower in a first mode of operation, or activating both the primary cam follower and one more than one secondary cam followers in a second mode of operation, depending on whether the coupling mechanism has been activated.

5. The coupling mechanism according to claim 4 , wherein disposing a locking pin within a cavity of the shaft activates the coupling mechanism.

6. The coupling mechanism according to claim 4 , wherein blocking a weep hole in fluid communication with a cavity of the shaft activates the coupling mechanism.

7. A method of modulating a valve event in an engine using a multi-mode valve control mechanism, the method comprising:

changing one of a frequency and a duration at which valves in a valve train are actuated by activating only a primary cam follower in a first mode of operation, or activating both the primary cam follower and at least one secondary cam followers in a second mode of operation, depending on whether the at least one secondary cam follower is decoupled or coupled to the primary cam follower, respectively.

8. The method according to claim 7 , wherein the one or more secondary cam followers are actuated prior to actuation of the primary cam follower.

9. The method according to claim 7 , wherein the one or more secondary cam followers are actuated subsequent to actuation of the primary cam follower.

10. The method according to claim 7 , wherein the one or more secondary cam followers are actuated while the primary cam follower is actuated.

11. The method according to claim 7 , wherein the one or more secondary cam followers are actuated for a longer period of time than the primary cam follower.

12. The method according to claim 7 , wherein the one or more secondary cam followers are actuated for a shorter period of time than the primary cam follower.