Hydrodynamic lubrication system for piston devices particularly Stirling engines

In a Stirling engine of the type having a displacer piston and power piston which reciprocate in cooperating cylinders confining a working fluid, hydrodynamic lubrication means comprising:

• (a) a plurality of turbine surfaces formed on and arranged around at least a first one of said pistons;
• and
• (b) a reservoir having an inlet for receiving a portion of said fluid and having at least one outlet positioned and formed to direct a flowing stream of said fluid to impinge upon said turbine surfaces to impart an average torque upon said first piston for causing said piston to rotate about its axis and entrain some of said fluid about its outer surface.

An apparatus for hydrodynamically lubricating a piston which reciprocates in a cylinder, said apparatus comprising:

• (a) means for applying a torque to said piston and inducing it to spin;
• and
• (b) drag means for exerting a dynamic counter torque upon said piston for regulating the angular velocity of said spinning piston.

In an expansible chamber device of the type having at least one cylinder with a piston mounted therein to permit its reciprocation and rotation about its axis, a fluid which at times flows into a portion of said cylinder and at times flows out of said cylinder, and fluid port means for intake and exhaust of said fluid, a plurality of turbine surfaces formed on and arranged around said piston;

• and at least one fluid port of said port means opening into said cylinder and positioned and formed to direct a flowing stream of said fluid to impinge upon said surfaces to impart an average torque upon said piston for causing said piston to rotate about its axis and entrain some of said fluid about its outer surface for hydrodynamic lubrication, the improvement comprising:
• a port means having a bifurcated port comprisinhg spaced intercommunicating openings, a first one of said openings formed in the wall of said cylinder in a position for periodically being blocked by a portion of said piston during an interval of its stroke, the second one of said spaced openings being said port which directs said flowing stream of fluid upon said turbine surfaces and positioned to direct said stream when said first opening is blocked.

A method for lubricating a piston of a free piston Stirling engine said method comprising applying a torque force to said piston causing it to spin sufficiently to entrain and drag along its outer surface some of the working fluid of the engine to separate its outer surface from the wall of said cylinder.

An improved Stirling engine of the type having a displacer piston and a power piston which reciprocate in cooperating cylinders confining a working fluid, wherein the improvement comprises a rotating motor drivingly linked to at least one of said pistons to apply a torque force to said piston causing it to spin sufficiently to entrain and drag along its outer surface some of said fluid to separate its outer surface from the wall of its cooperating cylinder.

An improved Stirling engine of the type having a displacer piston and a power piston which reciprocate in cooperating cylinders confining a working fluid, wherein the improvement comprises at least one fluidic diode mounted to at least one of said pistons and extending into a fluid flow path within one of said cylinders for applying a torque force to at least one of the pistons causing it to spin sufficiently to entrain and drag along its outer surface some of said fluid to separate its outer surface from the wall of said cylinder.