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.

A piston arrangement including a track and a piston moveable within a cylinder; wherein the track is adapted to rotate relative to the cylinder about an axis of rotation and has a cam surface and an edge surface extending away from the cam surface; wherein the piston is coupled to the track by a follower running on the cam surface; wherein the cam surface is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion within the cylinder in accordance with the path of the cam surface; wherein a stabilising element is connected to the piston, the stabilising element extending below the piston head and comprising a contact surface which engages the edge surface of the track.

A piston arrangement including a track and a piston moveable within a cylinder; wherein the track is adapted to rotate relative to the cylinder about an axis of rotation and has a cam surface and an edge surface extending away from the cam surface; wherein the piston is coupled to the track by a follower running on the cam surface; wherein the cam surface is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion within the cylinder in accordance with the path of the cam surface; wherein a stabilising element is connected to the piston, the stabilising element extending below the piston head and comprising a contact surface which engages the edge surface of the track.

A piston arrangement is provided. The piston assembly includes a track and a piston moveable within a cylinder. The track is rotatable relative to the cylinder about an axis of rotation and has a cam surface and an edge surface extending away from the cam surface. The piston is coupled to the track by a follower running on the cam surface. The cam surface is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion within the cylinder along a piston axis in accordance with the path of the cam surface. The piston axis is perpendicular to the track axis of rotation. A stabilizing element is connected to the piston, the stabilizing element extending below the piston head and comprising a contact surface which engages the edge surface of the track.

A piston arrangement is provided. The piston assembly includes a track and a piston moveable within a cylinder. The track is rotatable relative to the cylinder about an axis of rotation and has a cam surface and an edge surface extending away from the cam surface. The piston is coupled to the track by a follower running on the cam surface. The cam surface is shaped such that, as the track moves relative to the cylinder, the piston head moves in reciprocating motion within the cylinder along a piston axis in accordance with the path of the cam surface. The piston axis is perpendicular to the track axis of rotation. A stabilizing element is connected to the piston, the stabilizing element extending below the piston head and comprising a contact surface which engages the edge surface of the track.

In some aspects, reciprocating engines can include a first reciprocating mechanism that includes an axially translating y-axis component configured to reciprocate substantially along a y-axis with a reciprocating motion of a piston assembly relative to a base to which the y-axis component is slidingly attached. The first reciprocating mechanism can include an x-axis component slidingly coupled to and translating with the y-axis component along the y-axis, the x-axis component being: i) configured to reciprocate substantially perpendicularly to the y-axis relative to the y-axis component, ii) comprising an orbital output component, and iii) comprising an orbital linking component disposed substantially concentric with the orbital output component. The first reciprocating mechanism can include a stationary output component and a stationary linking component that are substantially concentric and disposed in a direction that is substantially perpendicular to the x-y plane.

In some aspects, reciprocating engines can include a first reciprocating mechanism that includes an axially translating y-axis component configured to reciprocate substantially along a y-axis with a reciprocating motion of a piston assembly relative to a base to which the y-axis component is slidingly attached. The first reciprocating mechanism can include an x-axis component slidingly coupled to and translating with the y-axis component along the y-axis, the x-axis component being: i) configured to reciprocate substantially perpendicularly to the y-axis relative to the y-axis component, ii) comprising an orbital output component, and iii) comprising an orbital linking component disposed substantially concentric with the orbital output component. The first reciprocating mechanism can include a stationary output component and a stationary linking component that are substantially concentric and disposed in a direction that is substantially perpendicular to the x-y plane.

Provided is an opposed-piston engine which attains high output, ensures combustion toughness, and includes a simplified configuration of a crankshaft counter-rotation synchronization mechanism which rotates crankshafts in engine units in opposite directions. An opposed-piston engine 10 of the present invention includes a first engine unit 11 and a second engine unit 21. The first engine unit 11 and the second engine unit 21 respectively include a first cylinder 12 and a second cylinder 22 independent of each other. In addition, a first valve driving mechanism 19 and a second valve driving mechanism 20 which control valves also function as a crankshaft counter-rotation synchronization mechanism 29 which rotates a first crankshaft 14 of the first engine unit 11 and a second crankshaft 24 of the second engine unit 21 in the opposite directions.

Provided is an opposed-piston engine which attains high output, ensures combustion toughness, and includes a simplified configuration of a crankshaft counter-rotation synchronization mechanism which rotates crankshafts in engine units in opposite directions. An opposed-piston engine 10 of the present invention includes a first engine unit 11 and a second engine unit 21. The first engine unit 11 and the second engine unit 21 respectively include a first cylinder 12 and a second cylinder 22 independent of each other. In addition, a first valve driving mechanism 19 and a second valve driving mechanism 20 which control valves also function as a crankshaft counter-rotation synchronization mechanism 29 which rotates a first crankshaft 14 of the first engine unit 11 and a second crankshaft 24 of the second engine unit 21 in the opposite directions.

In some aspects, reciprocating engines can include a drive mechanism for generating a rotational motion output from reciprocating piston assembly, where the drive mechanism includes an axially translating y-axis component to reciprocate along a y-axis with the piston assembly; an x-axis component: i) configured to reciprocate substantially perpendicularly to the y-axis, ii) having an internal ring gear, and iii) having an orbital engagement component substantially concentric with the internal ring gear; an output shaft assembly having an output pinion gear engaging tangentially with the internal ring gear; and a stationary engagement component substantially concentric with the output shaft assembly, the stationary engagement component interfacing with the orbital engagement component, the interfacing between the stationary engagement component and the orbital engagement component applying a force to the x-axis component to maintain contact between the internal ring gear and the output pinion gear.