A longitudinally adjustable connecting rod for a piston engine having a hydraulic control device for adjusting the effective length of the longitudinally adjustable connecting rod is provided. The hydraulic control device comprises a hydraulic control valve which has a control cylinder, a spool valve and at least one drain valve that can be actuated by the spool valve, wherein the spool valve comprises a control piston, which is displaceably guided in the control cylinder and to which hydraulic control pressure can be applied, and a slide plunger. The spool valve comprises two spool valve parts which can be separately manufactured and rigidly joined together for the intended use of the spool valve. Moreover, the invention relates to a spool valve for the hydraulic control valve of a longitudinally adjustable connecting rod and to a piston engine having at least one such longitudinally adjustable connecting rod.

An apparatus for adjusting a length of a connecting rod of a cylinder of an internal combustion engine by installing and/or removing an intermediate plate between a connecting rod small end and a connecting rod shank of the connecting rod in the state of the connecting rod, with the following assemblies: a pivot guard for the connecting rod small end mountable to the connecting rod small end between the connecting rod small end and a cylinder liner of the cylinder; supports mountable to counterweights of the cylinder on opposite sides of the connecting rod; holders mountable to the supports and extend between the supports perpendicularly to the same; lifting cylinders mountable to the holders and lift the connecting rod small end relative to the connecting rod shank with unscrewed screw connections between connecting rod small end and connecting rod shank.

A control device for a VCR connecting rod which can be operated by way of an actuation circuit is provided. Such a VCR connecting rod is to enable safe operation. For this purpose, a detection device is provided for determining a defect of the actuation circuit. Furthermore, the invention relates to a respectively associated method for operating an actuation circuit of a VCR connecting rod of an internal combustion engine.

A length-adjustable connecting rod for an internal combustion engine, where the connecting rod includes at least one switchable outlet valve for opening and closing a pressure chamber, where the outlet valve comprises a valve body and a closing body that is operatively connected to the valve body, and a closing mechanism is present acting upon the closing body for directly moving the closing body and indirectly moving the valve body from a closed to an open position or vice versa. Such an outlet valve is to be configured to be operable. For this purpose, this closing body has a mass which is smaller than the volume defined by the envelope contour of the closing body multiplied by the density of steel (7.85 g/mm.sup.3). The use of such a closing body for a respective length-adjustable connecting rod is also provided.

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.

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 switch over valve, in particular for controlling a hydraulic fluid flow, comprising: a contact element; and a sleeve shaped connecting section including a first bore hole for connecting with a first hydraulic fluid conduit, a second bore hole for connecting with a second hydraulic fluid conduit, and a relief bore hole for connecting with a relief channel, wherein the contact element is arranged in the sleeve shaped connecting section and optionally displaceable into a first switching position or a second switching position, wherein the first hydraulic fluid conduit is connected with the relief channel in the first switching position and the second hydraulic fluid conduit is connected with the relief channel in the second switching position, characterized in that the cut off valves are provided which are integrated into the switch over valve.

An apparatus can include: a piston head configured to be disposed inside of a cylinder of an engine; a connecting rod device coupled to the piston head and extending therefrom, the connecting rod device including: a variable-length connecting rod including a female component with a hollow body and a male component movably disposed at least partially inside of the female component, the male component configured to be coupled to a crankshaft of the engine, and a connecting rod magnet movably coupled to the female component; and a piston coupling mechanism disposed at least partially inside of the piston head to couple the connecting rod device to the piston head. The connecting rod device can be configured to transition between a coupled state and a de-coupled state.

A variable compression ratio (VCR) phaser configured to control a compression ratio of an engine having a crankshaft and a control shaft. The variable compress ratio phaser comprises: i) a control shaft gear configured to mesh with a gear on the control shaft of the engine and to receive torque from the control shaft; ii) a crankshaft gear configured to mesh with a gear on the crankshaft of the engine and to deliver torque to the crankshaft; and iii) a torque conversion mechanism configured to receive torque from the control shaft and to convert the torque to a linear force that changes the compression ratio of the engine.

A variable compression device includes a piston rod, a first fluid chamber configured to move the piston rod in a direction in which a compression ratio is increased by supplying a pressurized working fluid thereto, a regulation member configured to regulate movement of the piston rod in a direction in which a compression ratio is increased, a second fluid chamber provided between the piston rod and the regulation member and configured to store the working fluid, a supply flow path configured to guide the working fluid supplied to the second fluid chamber, a discharge flow path configured to guide the working fluid discharged from the second fluid chamber, and a flow rate regulation unit provided in the discharge flow path and configured to regulate a flow of the working fluid when the piston rod approaches the regulation member.