External-combustion, closed-cycle thermal engine

An external-combustion, closed-cycle thermal engine, comprising:

• a sealed gas chamber, a heater and a cooler;
• flow paths connecting the gas chamber and an inlet side and outlet side of the heater;
• flow paths connecting the gas chamber and an inlet side and outlet side of the cooler;
• on-off valves respectively provided in the flow paths on the inlet sides and outlet sides of the heater and cooler;
• and
• a means for moving a working gas;
• said external-combustion, closed-cycle thermal engine characterized in that:
• the on-off valves on the inlet side and outlet side of the cooler are closed to seal the cooler and the on-off valves on the inlet side and outlet side of the heater are opened to move and circulate the working gas in the gas chamber through the heater in order to heat the working gas in the gas chamber, or the on-off valves on the inlet side and outlet side of the heater are closed to seal the heater and the on-off valves on the inlet side and outlet side of the cooler are opened to move and circulate the working gas in the gas chamber through the cooler in order to cool the working gas in the gas chamber, thereby causing the working gas in the gas chamber to expand or contract to drive an operation body.