Patent ID: 11971021
Assignee: nan
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 20:
21. A thermal engine, comprising:
a heating fluid source;
a thermal battery including a heated thermal mass and a thermal mass fluid passageway passing adjacent to and in thermal communication with said heated thermal mass and said fluid passageway having a passageway in said thermal mass with a passageway entrance and a passageway exit;
a cylinder block containing at least one cylinder having a tubular cylinder side wall and a cylinder first end and a cylinder second end, defining a cylinder expansion chamber;
a valve block sealingly covering said cylinder first end having a cylinder intake opening and an intake valve in fluid communication with said cylinder, and a cylinder exhaust opening and exhaust valve in fluid communication with said cylinder;
an intake manifold connecting said heating fluid source to said cylinder intake opening through said intake valve;
a piston head slidably and sealingly retained within said cylinder expansion chamber; defining a variable volume expansion chamber between said piston head and said tubular cylinder side wall and said valve block;
a crankshaft rotatably mounted perpendicular to said cylinder at said cylinder second end;
a connecting rod pivotally connected to said piston head and to said crankshaft; said piston head defining an oscillatory linear motion within said expansion chamber synchronized with said crankshaft rotation such that an engine first stroke starts with said piston head defining a minimum expansion chamber volume and ends with said piston head defining a maximum expansion chamber volume, and an engine second stroke starts with said piston head defining at the maximum expansion chamber volume and ends with said piston defining a minimum expansion chamber volume;
and a thermally responsive shape memory alloy spring within said variable volume cylinder expansion chamber, extending between and bearing against said valve block and said piston head;
further during the start of said first stroke said shape memory alloy spring is in a minimally contracted martensitic state and said intake valve opens to let in heated heating fluid having a temperature sufficient to heat said shape memory alloy spring and thereby cause expansion of said shape memory alloy spring from a minimally contracted and martensitic state to a maximally extended and rigid 0 austenite state, pushing and thereby advancing said piston head within said expansion chamber to expand the volume of said expansion chamber to a maximum volume causing said exhaust valve to close, and driving said connecting rod to rotate said crankshaft and, said expansion of said expansion chamber lowering the pressure and the temperature of said expansion fluid within said expansion chamber and thereby cooling said expansion fluid and thereby also cooling said shape memory alloy spring, and said cooling causing said shape memory alloy spring to transition into martensitic state permitting and as said crankshaft continuous to rotate it returns said piston head and recompresses said shape memory alloy spring again to a minimally contracted and martensitic state, to repeat the cycle by starting another stroke.