A variable-length connecting rod comprises: a connecting rod head, designed to establish a pivot connection with a crankpin of a crankshaft, a hydraulic circuit for controlling the length of the connecting rod, and a system for controlling the hydraulic circuit. The control system comprises: at least one linear hydraulic slide arranged within a housing of the connecting rod head, at least a first shoe arranged on a sidewall of the connecting rod head, suitable for undergoing a bearing force exerted by a controlling member, the bearing force allowing the slide to be moved, a return means for bringing the slide back to its resting position in the absence of the bearing force, At and at least a second shoe arranged on the sidewall of the connecting rod head and suitable for undergoing the bearing force.

The invention relates to a check valve for a connecting rod for a variable compression internal combustion engine including at least one hydraulic chamber, the check valve including a valve body with a fluid path that is openable and closable by at least one closure element, wherein the at least one closure element is provided as an annular band. The invention also relates to a connecting rod for a variable compression internal combustion engine including a least one hydraulic chamber that is connectable by the at least one check valve with a bearing shell or a supply connection of the connecting rod or another hydraulic chamber.

Combustion engine with a variable compression ratio which, according to the invention, includes the following items: engine body, crankshaft with crank pins mounted rotatably in the body, cylinders, pistons connected to the crankshaft via pin connecting rod sand control arms as well as the control arm rod located inside the engine body, with eccentrics mounted on it, on which eccentrics for each piston there are separately mounted control arms, it is characterized by the fact that on the control arm rod (19) aside from the rigidly mounted eccentrics (18), on which single control arms (14) are rotatably mounted, there are also rotatably mounted eccentrics (23), on which single control arms (14) are rotatably mounted, where preferably on the eccentrics (18) are mounted the control arms (14) for one row of cylinders (5), while for the eccentrics (23) are mounted the control arms (14) for the other row of cylinders (5), additionally the engine contains a mechanism for changing the compression ratio consisting of the control arm rod (19) with eccentrics (18, 23) mounted on the control arm rod (19) as well as coupling elements that connect the elements of the mechanism which ensure that neighboring eccentrics (18, 23) rotate in opposite directions.

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.

A piston-crankshaft connector for an internal combustion engine can comprise a main connecting rod connected with its big end bore to a crankpin and at least one auxiliary connecting rod connected to off-axial surfaces made on the crankpin. On the piston side, the at least one auxiliary connecting rod can be attached to an upper crankpin nested within the main connecting rod, where the crankpin carries off-centred piston pin bore. Such construction can modify a piston pin bore distance relative to a main journal central axis during their rotation, which can improve the internal combustion stroke-to-stroke performance. A compression ratio can additionally or alternatively be adjusted by hydraulics acting on an entire segmented eccentric ring relative position within connecting rod bearing space via crankpin oil channels.

There is presented various embodiments disclosed in this application, including an improved crankshaft system using a load connecting member which provides a greater maximum torque angle than a conventional system, thereby improving efficiency and power.

A longitudinally adjustable connecting rod with a hydraulic control device for effecting a change in the effective length of the connecting rod is provided. The hydraulic control device comprises a hydraulic control valve which comprises a hydraulically actuatable control slide that is preloaded by way of a control slide spring, and two outlet valves which can be actuated by the control slide by way of two control contours arranged at a distance from one another. The control slide comprises a low-pressure section with a low-pressure piston for hydraulically actuating the control slide. For optimizing the control slide for such a longitudinally adjustable connecting rod, the two control contours are arranged together in a high-pressure section of the control slide which is arranged on one side of the low-pressure section and separated therefrom by way of a sealing section disposed therebetween. The control contours each comprise a closure region with control cams and an opening region adjoining the control cams. The closure region has a smaller cross-section than the opening region. The mass of the section of the control slide disposed between the two closure regions corresponds at most to 0.95 times the envelope volume of this section multiplied by the density of steel (7.85 g/mm.sup.3) due to the selection of material and/or the contouring narrowing in comparison with the opening regions. A respective control slide and a reciprocating piston engine are also provided.

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.

The invention relates to an adjustable-length connecting rod for a reciprocating piston engine, to a reciprocating piston engine, and to a vehicle, where an effective connecting rod length of the connecting rod can be changed, and the connecting rod has a hydraulic length adjustment device which has a hydraulic working chamber, a hydraulic duct, a valve recess with a valve recess longitudinal axis, and a valve device which is arranged in the valve recess and has a valve chamber, where the valve device is configured for opening and/or shutting of a hydraulic medium outflow from the hydraulic working chamber, and the hydraulic duct opens into the valve recess at an orifice opening in an inner wall section of the valve recess. The valve device has at least one closed outer wall section which lies opposite the orifice opening and surrounds the valve chamber of the valve device, where the outer wall section of closed configuration of the valve device configures a flow duct together with that inner wall section of the valve recess, where the flow duct is configured to divert hydraulic medium, which exits from the hydraulic duct with a first flow direction and enters into the valve recess, in a second flow direction which is different from the first flow direction before the entry into the valve chamber.

A longitudinally adjustable connecting rod for a piston engine, where the connecting rod includes a first connecting rod end for receiving a piston pin and a second connecting rod end for receiving a crankshaft journal, where the distance between the piston pin and the crankshaft journal is adjustable in the longitudinal direction (A) of the connecting rod by way of a hydraulic control device with a hydraulic control valve. The hydraulic control valve comprises a control cylinder and a control slide which is guided in a slidable manner in the control cylinder and which can be pressurized, and at least one outlet valve which can be actuated by the control slide. The control slide comprises a control piston which is arranged on the end face, with a control pressure surface which can be subjected to the hydraulic control pressure and which defines a control pressure chamber in the control cylinder. The use of such a longitudinally adjustable connecting rod with a hydraulic control device in a piston engine as well as a corresponding piston engine is also provided.