Paragraphs

Claims

The adjustment of the angle between both crankshafts, in the end-of-travel position of the variably timed transmission, in function of the appropriate dimensions of the different engine menbers, allow the engie to operate :

- in the expansion phase, with the combustion gases on the piston [8] associated at least from the maximum instantaneous torque on the crank of the short-stroke crankshaft [5] ;
- in the expansion phase, by limiting the rise of piston [8] prior to the opening of the exhaust valve [14], a source of combustion gas back pressure on said piston [8];
- at the end of the intake phase, by limiting the rise of piston [8], a cause of loss of filling volume within the cylinder [3].

This offers the advantage of maintaining the maximum specific output of the engine at full load.

The maximum compression ratio selected is achieved with the same data basis of dimensional values defined for the minimum compression ratio so that the minimum lead angle between the crank of the short-stroke crankshaft [5] and the crank of the long-stroke crankshaft [4], defined by the start-of-travel position of the variably timed transmission, determines at the end of the compression phase ( top dead center of piston [6] ), the position of piston [8] with respect to the additional volume required for the clearance space [40] to define said maximum compression ratio of the engine, with the connecting rod [9] of the crank of the short-stroke crankshaft [5] away from its top dead center, so that said connecting rod [9] forms an angle with the crank of the short-stroke crankshaft [5].

The adjustment of the angle between both crankshafts, in the start-of-travel position of the variably timed transmission, in function of the appropriate dimensions of the different engine members, allows the engine to operate :

- at the end of the compression phase, by providing a greater translational motion to piston [8] per unit degree of angular displacement between the cranks of the two crankshafts [4] and [5].

This offers the advantage of speeding up the modification process of the compression ratio of the engine at low load.

Claims