Patent ID: 7011056
Filing Date: 2006-03-14
Classification: F01L,F02B,Y02T

Abstract:
1. Variable timing device for reciprocating engines having at least two camshafts (AC 1 , AC 2 ), comprising, for one and the same cylinder, at least one admission valve (A) and at least one exhaust valve (E), which valves are actuated by said shafts, as well as angular phase shift means (D 1 , D 2 ) for at least one of said camshafts, characterized in that at least one and the same valve (A) is actuated by a hydraulic transmission means ( 4 , 9 , 10 ) which is capable of transmitting to said valve the movement of at least two cams (A 1 , A 2 ) belonging to separate camshafts (AC 1 , AC 2 ) which can be phase-shifted relative to one another, said transmission means comprising a cavity delimited by at least two deformable or movable surfaces ( 9 , 10 ) which are capable of being displaced by the cams (A 1 , A 2 ), as well as at least one deformable or movable valve surface ( 4 ), said surfaces being returned by resilient return means, being filled with a constant volume of hydraulic fluid equal to the volume of the cavity when the cams and the valve are at rest, so that, by virtue of the incompressibility of the hydraulic liquid, any displacement caused by a cam leads to displacement of the valve, and that any phase shift between the camshafts modifies the degree of displacement of the valve as a function of the angular position of the crankshaft.