Abstract: A telescopic control connecting rod for a variable compression ratio engine, comprises: a small end having, respectively, an eye and a piston at its ends; a big end serving as cylinder body in which the piston defines a first and a second hydraulic chamber, and a third side chamber located between the first and the second hydraulic chambers; the big end comprises two coaxial side bearings configured to establish a pivot link with a fixed part of the engine; a lubrication circuit comprising at least a first duct provided in the big end, connecting an inner space of each side bearing and the third chamber, whatever the length of the connecting rod, and comprising at least one second duct provided in the small end, connecting the third chamber and the eye.

Abstract: A hydraulic control system for a variable compression ratio engine, comprises: a control cylinder comprising a piston, a body in which two hydraulic chambers with equivalent sections are defined on either side of the piston and a return device arranged in one of the chambers, a hydraulic control circuit comprising: at least one duct connecting the two chambers to each other, and a controlled fluid discharging device for establishing or blocking a fluid communication between the chambers, at least one duct connecting one of the chambers to a low-pressure oil supply, and a refill valve, at least one duct connecting an oil outlet to at least one of the chambers, and a relief valve.

Abstract: A transmission device, particularly for an engine with variable compression rate and/or variable displacement, includes, in a cylinder housing: a combustion piston capable of moving in a combustion cylinder of the engine and secured to a transmission member; a gear engaging with a first rack of the transmission member and providing transmission of the movement between the combustion piston and a crankshaft of the engine; a connecting rod engaging, at a first end, with the gear and, at a second end, with the crankshaft; and a control member engaging with the gear and secured to a control piston. The combustion piston and the transmission member are slidably linked with the cylinder housing in a main direction.

Abstract: A bearing guide device of a combustion piston for a variable compression ratio engine. The movement of the combustion piston from a top dead center to a bottom dead center drives the movement of a synchronized roller made up of a cylindrical body and a pinion from a first position to a second position relative to first and second racks. According to the disclosure, the first and/or second racks have a different circular pitch than the pinion so that the flanks of the teeth of the pinion engage with the flanks of the teeth of the first and second racks only when the pinion is in the first or second position.

Abstract: transmission device, particularly for an engine with variable compression rate and/or variable displacement, includes, in a cylinder housing: a combustion piston capable of moving in a combustion cylinder of the engine and secured to a transmission member; a gear engaging with a first rack of the transmission member and providing transmission of the movement between the combustion piston and a crankshaft of the engine; a connecting rod engaging, at a first end, with the gear and, at a second end, with the crankshaft; and a control member engaging with the gear and secured to a control piston. The combustion piston and the transmission member are slidably linked with the cylinder housing in a main direction.

Abstract: A device for controlling the compression rate of a variable compression ratio engine comprises: an actuating cylinder comprising a piston defining two chambers for receiving a pressure fluid, a pressure accumulator supplying the pressure fluid, a first fluid circuit connecting the upper chamber to the accumulator and comprising a first valve assembly for controlling the flow of the fluid in the first fluid circuit, and a second fluid circuit connecting the lower chamber to the accumulator and comprising a second valve assembly for controlling the flow of a fluid in the second fluid circuit. At least one of the fluid circuits comprises a bypass conduit arranged so as to connect one of the chambers to the accumulator. The bypass conduit comprises a non-return valve.

Abstract: A bearing guide device of a combustion piston for a variable compression ratio engine. The movement of the combustion piston from a top dead center to a bottom dead center drives the movement of a synchronized roller made up of a cylindrical body and a pinion from a first position to a second position relative to first and second racks. According to the disclosure, the first and/or second racks have a different circular pitch than the pinion so that the flanks of the teeth of the pinion engage with the flanks of the teeth of the first and second racks only when the pinion is in the first or second position.

Abstract: A transmission device, particularly for an engine with variable compression rate and/or variable displacement, includes, in a cylinder housing: a combustion piston capable of moving in a combustion cylinder of the engine and secured to a transmission member; a gear engaging with a first rack of the transmission member and providing transmission of the movement between the combustion piston and a crankshaft of the engine; a connecting rod engaging, at a first end, with the gear and, at a second end, with the crankshaft; and a control member engaging with the gear and secured to a control piston. The combustion piston and the transmission member are slidably linked with the cylinder housing in a main direction.

Abstract: A device for controlling the compression rate of a variable compression ratio engine comprises: an actuating cylinder comprising a piston defining two chambers for receiving a pressure fluid, a pressure accumulator supplying the pressure fluid, a first fluid circuit connecting the upper chamber to the accumulator and comprising a first valve assembly for controlling the flow of the fluid in the first fluid circuit, and a second fluid circuit connecting the lower chamber to the accumulator and comprising a second valve assembly for controlling the flow of a fluid in the second fluid circuit. At least one of the fluid circuits comprises a bypass conduit arranged so as to connect one of the chambers to the accumulator. The bypass conduit comprises a non-return valve.

Abstract: A device for compensating for the operating clearances of an engine comprising a transmission device likely to move transversely in an engine block) during an engine cycle includes a pressing device exerting a holding force on the transmission device. The holding force is adjusted to the instantaneous speed of transverse movement of the transmission device in the engine block.

Abstract: transmission device, particularly for an engine with variable compression rate and/or variable displacement, includes, in a cylinder housing: a combustion piston, capable of moving in a combustion cylinder of the engine and secured to a transmission member; a gear engaging with a first rack of the transmission member and providing transmission of the movement between the combustion piston and a crankshaft of the engine; a connecting rod engaging, at a first end, with the gear and, at a second end, with the crankshaft; and a control member engaging with the gear and secured to a control piston. The combustion piston and the transmission member are slidably linked with the cylinder housing in a main direction.

Abstract: A device for compensating for the operating clearances of an engine comprising a transmission device likely to move transversely in an engine block) during an engine cycle includes a pressing device exerting a holding force on the transmission device. The holding force is adjusted to the instantaneous speed of transverse movement of the transmission device in the engine block.

Abstract: A clip-fastened raceway for a variable compression ratio engine includes: at least one curved segment whose outer surface cooperates with a raceway housed in the transmission member or in the control member of the variable compression ratio engine and whose inner surface is maintained in contact with a curved outer surface housed in the toothed wheel of the engine; at least one clip, housed in at least one of the ends of the curved segment and fastened to one or the other of the ends of the curved outer surface housed in the toothed wheel and hooking onto a hook or protrusion which the wheel includes in the vicinity of the end of its curved outer surface, the hook or protrusion being complementary to that of the clip so as to be able to cooperate with the latter.

Abstract: A clip-fastened raceway for a variable compression ratio engine includes: at least one curved segment whose outer surface cooperates with a raceway housed in the transmission member or in the control member of the variable compression ratio engine and whose inner surface is maintained in contact with a curved outer surface housed in the toothed wheel of the engine; at least one clip, housed in at least one of the ends of the curved segment and fastened to one or the other of the ends of the curved outer surface housed in the toothed wheel and hooking onto a hook or protrusion which the wheel includes in the vicinity of the end of its curved outer surface, the hook or protrusion being complementary to that of the clip so as to be able to cooperate with the latter.

Abstract: A clip-fastened raceway for a variable compression ratio engine includes: at least one curved segment whose outer surface cooperates with a raceway housed in the transmission member or in the control member of the variable compression ratio engine and whose inner surface is maintained in contact with a curved outer surface housed in the toothed wheel of the engine; at least one clip, housed in at least one of the ends of the curved segment and fastened to one or the other of the ends of the curved outer surface housed in the toothed wheel and hooking onto a hook or protrusion which the wheel includes in the vicinity of the end of its curved outer surface, the hook or protrusion being complementary to that of the clip so as to be able to cooperate with the latter.

Abstract: The elastic fixing for a piston (2) of a variable compression ratio engine (10) includes at least one metal rod (15) kept under tension between the piston (2) and the transmission member (3) and which applies a strong contact pressure between the base of the piston (2) and the top face of the transmission member (3), the piston (2) being tightened according to a previously calculated angle enabling the metal rod (15) consisting of a stud (16) to be subjected to a desired tension force and the tightening prestress to be reached between the piston (2) and the transmission member (3), and indexed in rotation relative to the transmission member (3), by an additional tightening which does not significantly increase the tightening pre-stress, the stud (16) continuing to elongate with the same tension force by plastic deformation.

Abstract: The elastic fixing for a piston (2) of a variable compression ratio engine (10) includes at least one metal rod (15) kept under tension between the piston (2) and the transmission member (3) and which applies a strong contact pressure between the base of the piston (2) and the top face of the transmission member (3), the piston (2) being tightened according to a previously calculated angle enabling the metal rod (15) consisting of a stud (16) to be subjected to a desired tension force and the tightening prestress to be reached between the piston (2) and the transmission member (3), and indexed in rotation relative to the transmission member (3), by an additional tightening which does not significantly increase the tightening pre-stress, the stud (16) continuing to elongate with the same tension force by plastic deformation.