A combustion engine comprising a switching rack and a plurality of connecting rods, where the switching rack comprises a longitudinal body having a face side and a rear side, where the face side comprises a plurality of switching arrangements where each switching arrangement comprises a first cam and a second cam, where each switching arrangement is adapted to interact with a switch on a connecting rod, and where the switching rack is arranged in a gliding manner in a groove between a cylinder block and an engine bedplate of the combustion engine. The advantage of the invention is that a means for switching a variable compression switch in a connecting rod in a combustion engine can be mounted in a simple and reliable manner.

Provided is a marine engine, including: a piston; and a compression ratio controller configured to execute lowering processing of moving a top dead center position of the piston toward a bottom dead center side when an engine rotation speed falls within a resonance occurrence range set in advance. A geometrical compression ratio is reduced, and a resonance stress caused by a torsional vibration in a rotary system can thus be suppressed while suppressing a decrease in thermal efficiency compared with a case in which retarding control is applied to a fuel injection timing or a closing timing of an exhaust valve.

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.

A crankshaft and conrod assembly (100) comprising a crankshaft (110) and a conrod (150), wherein the crankshaft (110) comprises at least one main journal (111) and one crankpin journal (112), where the crankshaft (110) is provided with an oil supply structure for supplying the crankpin journal (112) with lubrication oil and the conrod (150) with an oil pressure, wherein the oil supply structure comprises: an oil supply conduit (113) provided between the main journal and the crankpin journal (112), at least a first and a second oil supply opening (114, 115) provided at the crankpin journal (112), and a connection point (116) where the oil supply conduit (113) connects to the first and second oil supply opening (114, 115).

A length-adjustable connecting rod for a reciprocating piston machine, which may be a reciprocating piston internal combustion engine, is disclosed as well as a reciprocating piston machine and a vehicle. The connecting rod comprises a hydraulic length-adjusting device for adjusting an effective connecting rod length and a control device that can switch between two switching states, for controlling the length-adjusting device. The length-adjusting device comprises a hydraulic cylinder with a piston and a first hydraulic working chamber and a second hydraulic working chamber, the control device comprising a first valve and a second valve, the first valve of the control device being connected to the first hydraulic working chamber of the length-adjusting device in a fluid-communicating manner, and the second valve to the second hydraulic working chamber, the first valve and the second valve each being actuatable by means of a hydraulically actuatable adjusting piston that can axially move along an adjusting axis, the adjusting axis of the first valve being different from the adjusting axis of the second valve.

The invention relates to a method for operating a reciprocating piston machine, particularly an internal combustion engine, having at least one piston rod that is hydraulically adjustable in length for setting a compression ratio, wherein the piston rod comprises a piston and a hydraulic cylinder for adjusting its length, wherein the piston with the hydraulic cylinder delimits at least one working chamber, through the fill level of which at least two switching positions of the piston rod are possible, wherein independently from the setting of the compression ratio the working chamber is at least partially filled and emptied as a function of at least one first predetermined requirement to effect an at least partial exchange of a hydraulic medium in the at least one working chamber.

Provided is a control device for an internal combustion engine capable of estimating a compression ratio of the internal combustion engine at the time of fuel cut of the internal combustion engine and without being affected by an intake air amount and an intake air temperature. A compression ratio ε is calculated on the basis of a change of in-cylinder pressure P with respect to crank angle θ at timing when an in-cylinder volume change rate dV/dθ/V takes an extreme value or at timing from closing of an intake valve 109 to the start of ignition of the air-fuel mixture in the cylinder.

A lower link (7) is formed of two components by being divided at a dividing surface (14) including the central axis of a crank pin bearing portion (11), the two components including a lower link upper (15) with an upper pin bearing portion (12) and a lower link lower (16) with a control pin bearing portion (13). The dividing surface (14) includes a first dividing surface (14a) located more on the upper link side than the crank pin bearing portion (11) and a second dividing surface (14b) located more on the control link side than the crank pin bearing portion (11). In the lower link (7), the first dividing surface (14a) has a surface roughness larger than a surface roughness of the second dividing surface (14b).

Provided is a compression ratio varying mechanism, including a communication hole including: a first opening opened in an outer peripheral side surface of a piston rod; and a second opening, which is prevented from being opposed to the first opening in a radial direction of a piston rod, and is connected to an oil passage at a position apart from the first opening in a stroke direction.

Presented are variable compression ratio and independent compression and expansion engines, methods for making/operating such engines, and vehicles equipped with such engines. An engine assembly includes an engine block with a cylinder bore defining a combustion chamber, and a piston movable within the cylinder bore. A valve assembly, which is fluidly coupled to the combustion chamber, selectively introduces/evacuates fluid from the combustion chamber. A crankshaft is supported by the engine block and rotatable on a first axis. A multipoint linkage, which drivingly engages the piston to the crankshaft, rotates on a second axis offset from the first axis. A control shaft is supported by the engine block and rotates on a third axis offset from the first and second axes. The control shaft operable to selectively rotate the multipoint linkage on the second axis, and is operable to selectively unseat the valve assembly.