Patent ID: 8171730

Claim:
An external combustion engine provided with a pipe-shaped main container in which a working fluid is sealed flowable in a liquid state, a heating portion formed at a location at one end of said main container and heating the part of said working fluid in said main container to generate steam of said working fluid, a cooling portion formed at a location of said main container on the other end side thereof from said heating portion and cooling said steam to condense, an output part communicating with the other end of said main container and converting displacement of the liquid part of said working fluid generated due to the change in volume of said working fluid accompanying generation and condensation of said steam to mechanical energy for output, an auxiliary container communicating with said main container and having said working fluid sealed inside it, a venturi provided at a communicating part between said main container and said auxiliary container, a communicating member forming a communicating passage bypassing said venturi and communicating said main container and said auxiliary container, and a shutting means closing said communicating passage at the time of normal operation and opening said communicating passage at the time of startup, said output part having a piston displacing upon receiving pressure from the liquid part of said working fluid and a cylinder slidably holding said piston, said output part being driven as a startup means at the time of said startup, a displacement speed of said piston becoming the displacement speed of said piston at the time of normal operation or more when said output part is driven as said startup means, said communicating passage being formed so that when said output part is driven as said startup means and the displacement speed of said piston becomes the displacement speed of said piston at the time of normal operation or more, said pressure loss at the communicating passage becomes smaller than a saturated steam pressure at the temperature of said heating portion.