Simplified fluid pressure operated engine

A power plant operable with fluids under pressure comprising in combination,

• a plurality of cylinders,
• piston means for movement in said cylinders,
• means for cyclically reciprocating said piston means through reciprocation cycles for operating a rotary power plant takeoff shaft in an operation mode with fluid pressure applied to the piston means only in one direction of the reciprocation cycle,
• a source of fluid under pressure for use as fuel in said power plant,
• rotary distributor timing means,
• synchronizing means for synchronizing rotation of said rotary distributor with reciprocations of said piston means for cyclically gating fluid fuel from said source into said cylinders in a power stroke over a time period starting at top dead center of a reciprocation cycle of each said piston and ending substantially at bottom dead center of the reciprocation cycle for powering each cylinder to reciprocate each corresponding piston,
• a conduit path directed respectively from the rotary distributor timing means to each respective said cylinder to deliver fluid fuel, and
• asynchronously operating power plant intake-exhaust cylinder valving means for each cylinder comprising a pressure sensitive snap action diaphragm transfer valve coupled to noramlly close a transfer valve exhaust port coupled in the conduit path between the timing means and each respective cylinder to respectively pass fluid fuel into the cylinder during said power stroke and to snap into a condition exhausting the cylinder and closing the inlet fuel port in response to a change of fluid pressure differential between said distributor means and said cylinder.