Abstract: A continuously variable valve duration system including a rocker assembly acted upon by two off-spaced camshafts for selectively varying the closing point of a valve in an internal combustion engine. An opening camshaft is rotatably driven by the engine crankshaft and controls at least the opening and point of the valve through a rocker assembly disposed on a fixed pivot shaft. A closing camshaft, rotatably connected to the opening intake camshaft through a cam phaser, is poised to take over control of the valve closing event through the same rocker assembly. By changing the rotational phase of the closing camshaft relative to the opening camshaft via the cam phaser, the valve closing event can be either retarded or advanced so as to override the opening camshaft and thus selectively vary the valve event duration.

Abstract: A system for continuously varying actuation of a valve in an internal combustion engine including a first cam for opening the valve, a second cam for closing the valve, and an oscillating rocker arm continuously engaging each of the first cam, the second cam, and the valvetrain, with the aid of a lost motion spring. The cams are disposed on first and second camshafts that are geared together. The first camshaft gear is driven by the engine crankshaft and thus is phase-invariant. The second camshaft gear is rotationally mounted on the second camshaft and supports the stator of a camshaft phaser. The phaser rotor is mounted to the second camshaft. Varying the rotor position varies the phase of the second cam and thus varies lift and closing timing of the valve. The system is useful in improving the performance of both spark-ignited and compression-ignited engines.

Abstract: A continuously variable valve duration system including a rocker assembly acted upon by two off-spaced camshafts for selectively varying the closing point of a valve in an internal combustion engine. An opening camshaft is rotatably driven by the engine crankshaft and controls at least the opening and point of the valve through a rocker assembly disposed on a fixed pivot shaft. A closing camshaft, rotatably connected to the opening intake camshaft through a cam phaser, is poised to take over control of the valve closing event through the same rocker assembly. By changing the rotational phase of the closing camshaft relative to the opening camshaft via the cam phaser, the valve closing event can be either retarded or advanced so as to override the opening camshaft and thus selectively vary the valve event duration.

Abstract: An outwardly-opening fuel injector including a conical valve seat and conical valve head having nominally identical cone angles and mating lengths along the conical frustum between about 0.25 mm and about 0.30 mm. One of either the seat surface or the head surface is provided with an annular undercut to limit the length of mating contact to the desired range. The mating lengths and seal areas remain constant with use because the undercut prevents further changes in mating length. The resulting seal area prevents recession of the head into the seat with use, and therefore the valve stroke is predictable and constant. Further, the undercut provides a sharp corner in the fuel flow path downstream of the seal area, which increases the turbulent kinetic energy of fuel being discharged as a spray cone.