A pivot bearing suitable for two connecting rods in at least one piston of an internal combustion engine having two crankshafts, includes radial bearing regions that are provided with bolt boreholes and are disposed on either side of a center longitudinal plane of the piston and delimit connecting rod ends, forming an intermediate space. The bearing regions are designed as cylinder bodies having a crucible-like cross-section, of which each cylinder body has a base wall and a bearing ring jacket. The base walls of the two cylinder bodies extend at a distance from each other, and the bearing ring jackets surrounding the base walls are guided away from the base walls in opposite directions. One or more connecting supports run between the base walls. The bearing ring jackets cooperate with the piston boreholes in a rotatably movable manner. The base walls are connected to bearing bushings which are oriented in the axial direction of the pivot bearing and into which the bolt boreholes are incorporated. The pivot bearing is made of a material that brings about a targeted low-weight construction of the pivot bearing, while offering high strength and low wear.

Disclosed is a reciprocating piston engine, comprising a combined structure with an optimized double-crankshaft and variable compression ratio pistons, characterized in that the variable compression ratio piston is a piston serving as a double-acting hydraulic cylinder, a control valve bush of a slide-valve type directional control valve is fixed in a central mounting hole of the inner piston, and a control valve core is mounted in a rotatory sliding or nut-ball screw manner in a central mounting hole in the inner surface of the piston top; and the double-crankshaft engine is formed by two reverse rotating crankshafts which are coupled by gears to be in synchronous reverse rotation motion together, each piston being connected to a connecting rod shaft of two crankshafts, and a piston control valve driving mechanism being mounted between the two crankshafts.

An engine and gear train combination is provided which includes an engine which drives a first crankshaft having a first gear disposed thereon; a second crankshaft having a second gear and a flywheel disposed thereon, wherein the second gear meshes with the first gear; and a pulse compensator having a central element which is pivotally connected on a first end thereof to a first set of lateral members and which is pivotally connected on a second end thereof to a second set of lateral elements. Each element of the first set of lateral elements is also pivotally connected to the second crankshaft, and each element of the second set of lateral elements is pivotally connected to a mount.

A power unit for a hybrid vehicle is provided with a twin-cylinder reciprocating piston engine, which has two pistons which are guided in two cylinders in tandem arrangement. Two counter-directional crankshafts are connected with the pistons by connecting rods. At least one generator is rotatable co-directionally to the first crankshaft and counter-directionally to the second crankshaft. A camshaft with valve cams are operatively connected with control valves. A flywheel mass element is arranged on the second crankshaft or on a flywheel mass compensating shaft, and a compensating camshaft are provided. The compensating camshaft includes at least one compensating cam element which is operatively connected with a linearly guided compensating mass.

The outboard motor of the reciprocating piston internal combustion engine type has a crankshaft system with a crankshaft positioned upright within a machine housing of the internal combustion engine and having at an upper end region a flywheel. The flywheel is clad with a cover that extensively surrounds the flywheel starting at a top side of the internal combustion engine. Here, the crankshaft system has two parallel crankshafts that are each provided at their upper end regions with flywheels. The flywheels, when viewed in the axial direction of the crankshafts, are arranged offset with respect to each other and overlap in the manner of circular segments. The cover encapsulates the two flywheels over a significant range and is held in position on pivot axles of the flywheels.

A moment-cancelling, four-stroke engine is disclosed. The engine includes a first cylinder having a first piston and a second cylinder having a second piston, a first crankshaft operably connected to the first piston and a second crankshaft operably connected to the second piston. The first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction that is opposite the first direction to cancel the moments applied to the engine and reduce engine vibration.

A cylinder/reciprocating-piston device for a compressed air engine includes a hollow cylinder having a hollow-cylinder wall defining a pressure space, a piston that is movable the pressure space, and valves that respectively open/close valve flow channels in the hollow-cylinder wall. The hollow-cylinder has a surface that delimits the pressure space in a radial direction, a ceiling wall that axially upwardly delimits the pressure space, a floor wall that axially downwardly delimits the pressure space, and a piston-rod opening in the floor- and/or ceiling wall that slidably guide(s) a piston rod. The piston divides the pressure space into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall. A minimum flow-cross section of one or more of the valve flow channels is preferably at least 10% of the effective cross-sectional surface area of the piston.

A cylinder/reciprocating-piston device for a compressed air engine includes a hollow cylinder having a hollow-cylinder wall defining a pressure space, a piston that is movable the pressure space, and valves that respectively open/close valve flow channels in the hollow-cylinder wall. The hollow-cylinder has a surface that delimits the pressure space in a radial direction, a ceiling wall that axially upwardly delimits the pressure space, a floor wall that axially downwardly delimits the pressure space, and a piston-rod opening in the floor- and/or ceiling wall that slidably guide(s) a piston rod. The piston divides the pressure space into a first pressure chamber between the piston and the ceiling wall, and a second pressure chamber between the piston and the floor wall. A minimum flow-cross section of one or more of the valve flow channels is preferably at least 10% of the effective cross-sectional surface area of the piston.

In an opposed-piston mechanism, an intake compression cylinder and an expansion exhaust cylinder are individually provided, and a rotating perforated columnar valve and an ignition combustion chamber are formed therebetween. A valve mechanism is arranged on a cylinder side surface side, and a disk cam that moves in conjunction with crank rotation operates an intake valve and an exhaust valve on a cylinder side surface via a movable fulcrum type rocker arm. A movable structure of the rocker arm also realizes opening/closing amounts of the intake valve and the exhaust valve according to an operating situation of an engine. Since a piston pin and a piston pin can absorb variations of an engine that occur when two connecting rods are connected to one piston, the two connecting rods can be easily connected to the one piston.