Variable valve actuation
AssigneeFpt Motorenforschung AG
InventorHarald Fessler
Life of this patent
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Abstract
The present invention provides for Variable Valve Actuation comprising a cam, a valve suitable to displace between a closed position and an open condition caused by said cam, and further comprising a main rocker arm suitable to swing over a fulcrum, mechanically interacting with said valve, by means of a guide profile, and wherein said cam interacts with said main rocker arm causing said valve displacement as a consequence of said main rocker arm swinging. The target is to prevent a valve brake due to the guide profile and enable higher system stiffness. Accumulator less designs are feasible with this system.
Claims15
A Variable Valve Actuation comprising
- a cam,
- a valve suitable to displace between a closed position and an open condition caused by a rotation of said cam,
- and further comprising a main rocker arm suitable to swing over a fulcrum,
- mechanically interacting with said valve, by means of a guide profile, and wherein said cam interacts slidingly or rollingly with said main rocker arm causing said valve displacement as a consequence of said main rocker arm swinging,
- wherein said variable valve actuation is obtained by a hydraulic interconnection that is arranged to move said fulcrum relative to said cam to modify said mechanical interaction;
- wherein said cam interacts directly with said main rocker arm and said fulcrum is movable;
- wherein said fulcrum is supported by a support piston of a hydraulic circuit that forms part of the hydraulic interconnection.
A variable valve actuation comprising:
- a cam,
- a valve suitable to displace between a closed position and an open condition caused by a rotation of said cam,
- and further comprising a main rocker arm suitable to swing over a fulcrum,
- mechanically interacting with said valve, by means of a guide profile, and wherein said cam interacts slidingly or rollingly with said main rocker arm causing said valve displacement as a consequence of said main rocker arm swinging,
- wherein said variable valve actuation is obtained by a hydraulic interconnection that is interposed between said cam and said main rocker arm and is arranged to modify said mechanical interaction;
- wherein said cam interacts indirectly with said main rocker arm and said fulcrum is fixed,
- wherein said indirect interaction comprises the hydraulic interconnection that comprises a master piston and a slave piston;
- wherein said main rocker is globally shaped as an anchor and wherein said slave piston interacts with an intermediate portion of a stem of the anchor.
A variable valve actuation comprising:
- a cam,
- a valve suitable to displace between a closed position and an open condition caused by a rotation of said cam,
- and further comprising a main rocker arm suitable to swing over a fulcrum,
- mechanically interacting with said valve, by means of a guide profile, and wherein said cam interacts slidingly or rollingly with said main rocker arm causing said valve displacement as a consequence of said main rocker arm swinging,
- wherein said variable valve actuation is obtained by a hydraulic interconnection that is interposed between said cam and said main rocker arm and is arranged to modify said mechanical interaction;
- wherein said cam interact indirectly with said main rocker arm and said fulcrum is fixed;
- wherein said main rocker arm is arranged to define a slave double-action piston defining two opposite first chambers, each chamber being connected to an individual hydraulic circuit that forms part of the hydraulic interconnection, wherein each of said hydraulic circuits is connected with a chamber of a master double-action piston including opposite second chambers, wherein the master double-action piston is fixed with a shaft, bearing a roller in mechanical contact with said cam, so that an interaction of said roller with said cam causes said master double-action piston to slide, pumping oil in one of said hydraulic circuits at a time, causing said main rocker arm to swing.
Dependencies are inferred from the claim text.