Variable compression ratio engines and methods for homogeneous charge, compression ignition operation. The engines effectively premix the fuel and air well before compression ignition. Various embodiments are disclosed including embodiments that include two stages of compression to obtain compression ratios well above the mechanical compression ratio of the engine cylinders for compression ignition of difficult to ignite fuels, and a controllable combustion chamber volume for limiting the maximum temperature during combustion. Energy storage with energy management are also disclosed.

Variable compression ratio (VCR) in reciprocating internal combustion engine must be achieved in very short time or in less than 10 degrees from TDC. To accomplish this a closed-circuit system of hydraulic cylinder pump-follower driven by End-Cam, centered on the crankshaft journal, and a hydraulic jack linked to a mechanical scissor jack. This arrangement speeds up the VCR action while reduces pressure load on the VCR mechanism and allows for higher compression ratio. The rotation of the End-Cam with respect to the hydraulic cylinder pump engages the plunger-follower with the Cam rise/lift at TDC. Then starts pumping oil to the hydraulic jack that is linked to the scissor jack and lift/push up the engine piston. Addition of an actuator to the End-Cam advances or delays VCR action. This hydraulic-mechanical system is compact is size with options for various mechanical linkages and customizable in different ways that two configurations are presented.

A crank drive for a reciprocating-piston engine includes a crankshaft which has at least one crank pin. At least one eccentric is rotatably arranged on the crank pin via which at least one connecting rod is to be rotatably mounted on the crank pin. A piston can be arranged so as to move in a translatory fashion in a cylinder having a variable compression ratio of the reciprocating-piston engine and can be coupled in an articulated fashion via the connecting rod to the crankshaft. At least one actuator shaft is arranged coaxially with respect to the crankshaft, by which actuator shaft the eccentric can be rotated relative to the crank pin by driving the actuator shaft. As a result, the compression ratio of the cylinder can be adjusted. An actuator element, by which the actuator shaft can be driven, is arranged at one end of the crankshaft and adjoins the actuator shaft in the axial direction of the crankshaft.

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.

Variable compression ratio engines and methods for homogeneous charge, compression ignition operation. The engines effectively premix the fuel and air well before compression ignition. Various embodiments are disclosed including embodiments that include two stages of compression to obtain compression ratios well above the mechanical compression ratio of the engine cylinders for compression ignition of difficult to ignite fuels, and a controllable combustion chamber volume for limiting the maximum temperature during combustion. Energy storage with energy management are also disclosed.

Methods and systems are provided for a piston. In one example, system may comprise a piston comprising a chamber in which a piston bowl may actuated independent of an oscillation of the piston. The chamber may receive a hydraulic fluid in order to adjust a position of the piston bowl within the chamber, thereby adjusting a compression ratio of a combustion chamber in which the piston may oscillate.

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.

There is provided an assembly for an engine configured for linking a piston to a crankshaft (6) of the engine, comprising a pair of primary connecting rods (1a, 1b) configured to link said piston (1) to a secondary connecting rod (2), the secondary connecting rod (2) comprises an upper portion (2a) and a lower portion (2b); a controlling member (3) having a pair of opposed guiding rails (3a, 3b) and a pair of aligned lateral pin joints (30a, 30b), the controlling member (3) is configured to receive a substantial part of the upper portion (2a) of said secondary connecting rod (2); and a controlling member (3) support element configured to enclose the controlling member (3) within a cylinder block (5) of said engine, wherein the secondary connecting rod upper (2a) and lower portions (2b) are connected to each other when a crank shaft joint (8) is trapped between two semi-circular space gaps (28) in each of said secondary connecting rod upper (2a) and lower (2b) portions.

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.

An engine includes an engine shaft and a piston configured to reciprocate within a cylinder chamber having an axis, each piston having an first piston part and piston stem to move in unison with or separately from a second piston part to define piston strokes for different thermal functions of the engine. The engine further includes a linkage assembly having a first end coupled to the engine and a second end coupled to the piston stem defining a copy point, an actuator that engages the linkage assembly, and a guide cam that engages a guide cam follower on the linkage assembly. The actuator and the guide cam are operable to control motion of the linkage assembly to thereby define substantially linear movement of the copy point along the cylinder chamber axis.