High efficiency steam engine having improved steam cutoff control

A steam engine comprising,

• a cylinder having a piston that is sealingly and slidably mounted therein at one end of a steam expansion chamber and is operatively connected to a crankshaft,
• a steam inlet valve that is constructed to seal a valve seat in the engine that communicates between a steam supply port and the steam expansion chamber,
• a cutoff control valve mounted for reciprocation in the engine that is constructed and arranged to seal an outlet to the steam expansion chamber and
• a lifter supported to reciprocate with the piston in a position to close the cutoff control valve as the piston approaches top dead center thereby sealing the steam expansion chamber proximate but prior to an end of the exhaust stroke such that a residual quantity of steam remaining in the steam expansion chamber is compressed by movement of the piston proximate an end of the exhaust stroke to a pressure that opens the inlet valve in response to a force applied to the inlet valve by the steam thus compressed.

A steam engine comprising,

• a cylinder having a piston that is sealingly and slidably mounted therein at an end of a steam expansion chamber and is operatively connected to a crankshaft,
• a steam inlet valve that is constructed to seal a valve seat in the engine that communicates between a steam supply port and the steam expansion chamber,
• a steam exhaust valve communicating with the steam expansion chamber,
• an electromagnet constructed for holding an armature proximate thereto when electric current is supplied thereto, the armature being operatively associated with the steam inlet valve and
• a cutoff valve that is mounted in the engine for reciprocation and is responsive to actuation by the electromagnet to close the steam inlet valve at a time selected for the cutting off the admission of steam to the expansion chamber.