Internal combustion engine valve actuation and adjustable lift and timing
A cam can rotate on a camshaft of an internal combustion engine. A rocker arm that actuates a valve of the internal combustion engine can include a rocker pivot connection point located on a distal side of a valve component from a proximate end of the rocker arm that is deflected by action of the cam. The rocker arm can include a contact point located between the rocker pivot point and the proximate end. The contact point can act on the valve component to actuate the valve. The rocker pivot connection point can be translated such that it is closer to or further from the cam. This translation can be used to vary valve lift and/or valve timing. The cam can have a three-dimensional profile to provide different actuation distance of the rocker arm. Systems, methods, and articles of manufacture consistent with one or more of these features are described.
1. A system comprising:
a cam that rotates on a camshaft of an internal combustion engine comprising opposing first and second pistons and a sleeve valve having a central axis, the first piston, the second piston and a wall of the sleeve valve at least partially defining a combustion chamber, the wall of the sleeve valve defining a cylinder, the cam being positioned external to the cylinder and disposed on a first side of the central axis; and
a rocker arm that actuates the sleeve valve, the rocker arm comprising a rocker pivot connection point located on a distal end of the rocker arm, which is disposed on an end opposite from a proximate end of the rocker arm that is deflected by action of the cam, the rocker pivot connection point positioned external to the cylinder and disposed on a second side of the central axis opposite to the first side of the central axis, the rocker arm comprising a contact point located between the rocker pivot point and the proximate end, the contact point acting on a component of the sleeve valve to actuate the sleeve valve.
2. A system as in claim 1 , further comprising a pivot connection point translation system, the pivot connection point translation system causing the pivot connection point to move closer to or farther from the cam according to a throttle input received from a throttle control device.
3. A system as in claim 2 , wherein moving the pivot connection point closer to the cam results in reducing an amount of lift experienced by the valve off a valve seat under actuation by the rocker arm and moving the pivot connection point farther from the cam results in increasing the amount of lift experienced by the valve off the valve seat under actuation by the rocker arm.
4. A system as in claim 2 , wherein moving the pivot connection point closer to the cam results in an earlier actuation of the valve under actuation by the rocker arm and moving the pivot connection point farther from the cam results in a delayed actuation of the valve under actuation by the rocker arm.
5. A system as in claim 1 , wherein the cam comprises a three-dimensional cam profile comprising at least two cam profiles that result in differing deflection distances of the proximate end of the rocker arm.
6. A system as in claim 5 , wherein the three-dimensional cam profile further comprises a continuously variable cam profile.
7. A system as in claim 5 , wherein the proximate end of the rocker arm comprises a rotatable follower that rotates relative to the rocker arm in response to interacting with the at least two cam profiles.
8. A system as in claim 1 , wherein the proximate end of the rocker arm comprises a follower that interacts with the cam.
9. A system as in claim 1 , wherein the valve comprises a sleeve valve.
10. A system as in claim 1 , wherein the valve comprises a poppet valve.
11. A method comprising:
rotating a cam of an internal combustion engine by causing rotation of a camshaft upon which the cam is mounted, the internal combustion engine comprising opposing first and second pistons positioned within a sleeve valve having a central axis, wherein the first piston, the second piston and a wall of the sleeve valve at least partially define a combustion chamber, with the wall of the sleeve valve defined by a cylinder, and wherein the cam is positioned external to the cylinder and disposed on a first side of the central axis; and
actuating a valve of the internal combustion engine by motion of a rocker arm, the rocker arm comprising a rocker pivot connection point located on a distal end of the rocker arm, which is disposed on an end opposite from a proximate end of the rocker arm that is deflected by action of the cam, the rocker pivot connection point positioned external to the cylinder and disposed on a second side of the central axis, with the first side and second side positioned on opposing sides of the central axis, the rocker arm further comprising a contact point located between the rocker pivot point and the proximate end, the contact point acting on the valve component to actuate the valve.
12. A method as in claim 11 , further comprising translating the pivot connection point to causes the pivot connection point to move closer to or farther from the cam according to a throttle input received from a throttle control device.
13. A method as in claim 12 , wherein moving the pivot connection point closer to the cam results in reducing an amount of lift experienced by the valve off a valve seat under actuation by the rocker arm and moving the pivot connection point farther from the cam results in increasing the amount of lift experienced by the valve off the valve seat under actuation by the rocker arm.
14. A method as in claim 12 , wherein moving the pivot connection point closer to the cam results in an earlier actuation of the valve under actuation by the rocker arm and moving the pivot connection point farther from the cam results in a delayed actuation of the valve under actuation by the rocker arm.
15. A method as in claim 11 , wherein the cam comprises a three-dimensional cam profile comprising at least two cam profiles that result in differing deflection distances of the proximate end of the rocker arm.
16. A method as in claim 15 , wherein the three-dimensional cam profile further comprises a continuously variable cam profile.
17. A system as in claim 15 , wherein the proximate end of the rocker arm comprises a rotatable follower that rotates relative to the rocker arm in response to interacting with the at least two cam profiles.
18. A method as in claim 11 , wherein the proximate end of the rocker arm comprises a follower that interacts with the cam.
19. A method as in claim 11 , wherein the valve comprises a sleeve valve.
20. A method as in claim 11 , wherein the valve comprises a poppet valve.