Heat engine with variable volume displacement means

Abstract

A heat engine based on the Stirling cycle in which the conventional displacer piston and power piston are replaced by a single variable volume displacement unit. The variable volume displacement unit is disposed in a chamber having a heat input side and a heat removal side, and comprises two pivotally supported baffle plates movable relative to each other. The baffle plates divide the chamber into first, second and third regions each of variable volume, with the total volume of the three regions remaining constant. A regenerator interconnects the first and second regions for removing heat from, or returning heat to, a working fluid as it passes back and forth between the first and second regions. In the third region, a driving mechanism interconnects the baffle plates to time their movements and drive the output means which may be located outside of the chamber or inside the chamber within the third region. The mechanical linkage is arranged such that movement of one of the baffle plates causes the other baffle plate to move at a different rate thereby varying the volume of the third region during the isothermal expansion and isothermal compression phases of a cycle. Condensate from the working fluid may be collected and returned to the working fluid as the fluid passes into the regenerator from the cold side, the condensate return line including a pump and a throttle valve for controlling the speed of operation of the engine.