An inlet-valve arrangement is for an external-heat engine, which includes at least one working chamber, each one having a cooperating piston. The working chamber is supplied with a working fluid via at least one controlled poppet valve. The poppet valve is arranged to open in the opposite direction to the flow direction of the working fluid. The center axis of the poppet valve is arranged perpendicularly within a deviation of 45 degrees relative to the center axis of the piston.