A variable-compression-ratio engine may include a piston pin configured to interconnect a piston and an end portion of a connecting rod; an eccentric cam rotatably provided around the end portion of the connecting rod so that the piston pin is provided eccentrically to the eccentric cam, the eccentric cam serving to eccentrically rotate the piston pin via rotation thereof to vary a height of a top dead point of the piston; a latching plate configured to eject an oil, supplied thereinto, outwards in a circumferential direction through an oil ejection hole formed in an external peripheral surface thereof, to be rotated by an ejection pressure of the oil, the latching plate being rotated with the eccentric cam; and an oil supply device configured to selectively supply the oil into the latching plate.

Methods and systems are provided for improving calibration of a variable compression ratio engine. Cylinder-to-cylinder compression ratio variations are detected and accounted for by comparing cylinder fuel flow and IMEP at each compression ratio setting. Dilution parameters including EGR and VCT schedule are also calibrated to account for the cylinder-to-cylinder compression ratio variations.

Methods and systems are provided for improving calibration of a variable compression ratio engine. Cylinder-to-cylinder compression ratio variations are detected and accounted for by comparing cylinder fuel flow and IMEP at each compression ratio setting. Dilution parameters including EGR and VCT schedule are also calibrated to account for the cylinder-to-cylinder compression ratio variations.

A uniflow scavenging two-cycle engine includes an scavenging port having a swirling guide portion that guides scavenging gas into a cylinder in a direction inclined with respect to a radial direction of the cylinder, and a center guide portion that is provided to be closer to a crank side of the cylinder than the swirling guide portion and guides the scavenging gas further toward the center side of the cylinder than the swirling guide portion. At least a part of the center guide portion faces a piston when the piston is positioned at bottom dead center during the high compression ratio mode, and the center guide portion and the piston do not face each other or an area of facing the piston is smaller than that during the high compression ratio mode when the piston is positioned at bottom dead center during the low compression ratio mode.

A switch valve for controlling a hydraulic fluid flow of a connecting rod for an internal combustion engine with variable compression with an eccentrical element adjustment arrangement for adjusting an effective connecting rod length, the switch valve including a valve housing including a first operating connection and a second operating connection and a supply connection, wherein at least one filter element is arranged in a portion of the first operating connection or the second operating connection or the supply connection. The switch valve is advantageously used in a connecting rod for an internal combustion engine with variable compression.

A dual-crankshaft engine includes a piston and two crankshafts constituting a double-crank mechanism, and further includes a cylindrical block. The cylindrical block includes a cylinder portion and a crankshaft support portion. A lower end of the piston is a piston guiding rod. A piston rod guiding groove is provided in the cylindrical block. A lower end of the piston is opened, and provided with a piston end cover. The piston end cover and the piston guiding rod are detachably and fixedly connected. The piston is a non-skirted piston where the piston sealing end is separated from the piston guiding end. The piston sealing end is the piston head of the piston. The piston guiding end is the piston guiding rod and the piston rod guiding groove. The piston is designed to be equi-stress, which increases the strength.

An internal combustion engine that includes a variable stroke piston is described. The described engine includes a variable valve timing system and optional variable compression ration system. In embodiments, an electronic control unit coordinates the operations of the variable stroke piston, variable valve timing system, and variable compression ratio system in order to optimize engine performance across a wide range of engine conditions.

A power cylinder assembly for an internal combustion engine includes a cylinder wall that surrounds a cylinder bore that extends along an axis. A piston assembly is positioned in the cylinder bore, and the piston assembly has a combustion surface that divides the cylinder bore into a combustion chamber on one axial side of the combustion surface and a crank case on an opposite axial side of the combustion surface. The combustion surface is partially defined by a first upper surface of a first piece and partially defined by a second upper surface of a second piece. The second piece is moveable relative to the piston body during operation of the power cylinder assembly to change a compression ratio of the power cylinder assembly.

An internal combustion engine includes: a variable compression ratio mechanism arranged to vary an engine compression ratio in accordance with a rotation position of a control shaft; an actuator arranged to vary the rotation position of the control shaft; an arm portion extending from the control shaft in a radially outward direction; a lever arranged to link the actuator and the arm portion; a link pin which penetrates the lever and the arm portion, and which rotatably links the lever and the arm portion; and a wall portion which confronts an end surface of the link pin irrespective of the rotation position of the control shaft, and which retains the link pin to the lever or the arm portion.

Methods and systems are provided for adjusting an ignition timing of an internal combustion engine responsive to a biasing force of a pressure-reactive piston. In one example, an engine may include a pressure-reactive piston having a top wall biased away from a piston base by a pressure of gas contained within the base. An ignition timing of a combustion chamber including the piston is adjusted responsive to an estimated biasing force of the gas against the top wall.