Hub-hub connection for a power unit

A power unit comprising:

• a reciprocating-piston engine (engine) having at least one generator drivingly connected to the engine, the engine including a first hub coupled to a second hub by a first connection;
• at least two pistons included in the engine guided in at least two cylinders arranged in tandem;
• first and second crankshafts connected to the pistons by connection rods running in opposite directions and mechanically coupled in a same phase;
• and
• a connection disk configured, dimensioned and arranged as a second connection for transmitting torque from the first hub to the second hub such that an angular position between the hubs is continuously adjustable on installation, wherein the first hub and the second hub rest on each of a plurality of surfaces of the connection disk, and wherein the surfaces of the connection disk include a matrix of hard materials for frictional engagement of the hubs, wherein the frictional engagement is by one of a screw screwed into an inner thread of the first hub or a hub nut screwed with an outer thread of the first hub.

A power unit comprising:

• a reciprocating-piston engine (engine) having first and second generators connected to the engine via first and second crankshafts respectively, the engine including at least two pistons guided in at least two cylinders arranged in tandem, the crankshafts connected to the pistons by connection rods running in opposite directions and mechanically coupled in a same phase;
• a first hub coupled to a second hub included in the engine by a first connection;
• and
• a connection disk configured, dimensioned and arranged as a second connection for transmitting torque from the first hub to the second hub such that an angular position between the hubs is continuously adjustable on installation, wherein the first hub and the second hub rest on each of a plurality of surfaces of the connection disk, and wherein the surfaces of the connection disk include a matrix of hard materials for frictional engagement of the hubs.