Linear cross-head bearing for stirling engine
AssigneeNew Power Concepts LLC
InventorsChristopher C. Langenfeld, Prashant Bhat, Mithun R. Bhat, Dean Kamen
Life of this patent
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Abstract
An external combustion engine including a burner element, a heater head, a piston cylinder containing a piston, a cooler and a crankcase. The crankcase includes a crankshaft, a piston rod connected to the piston, a drive mechanism for converting the linear motion of the piston rod to rotary motion of the crankshaft and a linear cross-head bearing that is connected rigidly to the piston rod at one end and to the drive mechanism at the other end. Also the external combustion engine includes a piston clearance seal and a piston rod seal unit that has floating rod seals. The piston includes a inner dome to reduce axial heat transfer via radiation and convection.
Claims26
An external combustion engine containing a working fluid and comprising:
- a burner element for heating the working fluid of the engine;
- at least one heater head defining a working space containing the working fluid;
- at least one piston cylinder containing a piston for compressing the working fluid;
- at least one cooler for cooling the working fluid;
- a crankcase comprising:
- a crankshaft for producing an engine output;
- a piston rod connected to the piston;
- a drive mechanism that converts the linear motion of the piston rod to rotary motion of the crankshaft;
- and
- a linear cross-head bearing comprising a journal and a guide, wherein the journal has a first end rigidly attached to the piston rod and a second end attached to the drive mechanism,
- wherein the ratio of the linear cross-head bearing length over diameter is greater than 2.0,
- wherein the guide is located outside the working space, and
- wherein the linear cross-head bearing solely constrains the motion of the piston.
An external combustion engine containing a working fluid and comprising:
- a burner element for heating the working fluid of the engine;
- at least one heater head defining a working space containing the working fluid;
- at least one piston cylinder containing a piston for compressing the working fluid;
- at least one cooler for cooling the working fluid;
- a crankcase comprising:
- a crankshaft for producing an engine output;
- a piston rod connected to the piston;
- a rocking beam driven by the piston rod;
- a connecting rod connected at a first end to the rocking beam and at a second end to a crankshaft to convert rotary motion of the rocking beam to rotary motion of the crankshaft;
- and
- a linear cross-head bearing comprising a journal and a guide, wherein the journal has a first end rigidly attached to the piston rod and a second end attached to the rocking beam,
- wherein the ratio of the linear cross-head bearing length over diameter is greater than 2.0,
- wherein the guide is located outside the working space, and
- wherein the motion of the piston is solely constrained by the linear cross-head.
An external combustion engine containing a working fluid and comprising:
- a burner element for heating the working fluid of the engine;
- at least one heater head defining a working space containing the working fluid;
- at least one piston cylinder containing a piston for compressing the working fluid;
- at least one cooler for cooling the working fluid;
- a crankcase comprising:
- a crankshaft for producing an engine output;
- a piston rod connected to the piston;
- a drive mechanism that converts the linear motion of the piston rod to rotary motion of the crankshaft;
- and
- a piston comprising:
- a piston base wherein at least one piston seal is mounted, the piston base comprising a small orifice to allow the pressure inside the piston to equalize with average pressure of the work space, the orifice diameter being between 0.002 and 0.008 inches;
- an outer shell that mounts to the base and defines the outside of the piston above the base;
- and
- an inner shell has is shorter and narrower than the outer shell and defines with the piston base a volume above the inner surface of the piston base.
Dependencies are inferred from the claim text.