Patent ID: 9181823
Filing Date: 2015-11-10
Classification: F01L

Abstract:
1. A control device for actuating at least one valve, e.g. for a reciprocating engine, the valve being driven with reciprocating motion in rectilinear translation to open or close an orifice having a sealing seat, said valve including resilient return means urging said valve towards a closed position, said device comprising a body including a non-deformable cavity communicating exclusively with the outside via at least four rectilinear cylinders that are closed respectively by four pistons (P 1 , P 2 , Pa, Ps), each of said pistons being movable in reciprocating motion between a respective bottom dead-center remote from the inside of the non-deformable cavity and a top dead-center close to the inside of the non-deformable cavity, the device being characterized in that said pistons comprise a piston (Ps) mechanically connected to the valve and opposing its return means, an opening piston (P 1 ) actuated by an opening cam (C 1 ) that is driven in rotation by a first shaft, a closing piston (P 2 ) actuated by a closing cam (C 2 ) that is driven in rotation by a second shaft that rotates synchronously with the first shaft and that may be offset in operation relative to the first shaft through an adjustable angle, and a shuttle piston (Pa) movable between a first stationary abutment defining its bottom dead-center and a second stationary abutment defining its top dead-center, the shuttle piston (Pa) being urged towards its top dead-center by resilient means, in that the portion of the non-deformable cavity that extends between the pistons (P 1 , P 2 , Pa, Ps) is filled with a constant reference volume of substantially incompressible hydraulic fluid that is defined when the valve rests against its seat, when the opening and closing pistons (P 1 , P 2 ) are at their bottom dead-centers, and when the shuttle piston (Pa) is at its top dead-center, in that the opening piston (P 1 ), the closing piston (P 2 ), and the shuttle piston (Pa) have a common cylinder capacity and move a same volume of fluid between their bottom and top dead-centers, and in that the resilient return means of the shuttle piston (Pa) and of the valve are such that the fluid pressure needed for moving the shuttle piston (Pa) to its bottom dead-center is less than the pressure needed for opening the valve.