Patent ID: 8757108
Filing Date: 2014-06-24
Classification: F02B,Y02T

Abstract:
1. A method for operating an opposed-piston internal combustion engine cycle for enabling highly efficient stratospheric flight, comprising: (i) Providing an internal combustion engine in operation having a plurality of cylinders disposed symmetrically about a main shaft, each cylinder enclosing a pair of first and second opposed pistons, each of said pistons connected to a piston rod, wherein each piston translates back and forth along the long axis of the cylinder and wherein the combined motion of the piston pair is synchronized to allow the cyclical translation of the first piston to be in phase with that of the second piston, whereby each piston reaches their respective top dead center and bottom center positions at substantially the same time, and whereby the volume of the cylinder is defined by the product of the distance between the top surfaces of the first and second pistons and the cross sectional area of the cylinder, the maximal volume V (ii) Providing a gaseous working fluid having a temperature T (iii) Opening one or more exhaust ports disposed in the wall of each cylinder substantially near the end of the expansion phase of the previous engine cycle wherein the volume of the cylinder is substantially near V (iv) Opening one or more intake ports disposed in the wall of each cylinder in succession to the opening of the one or more exhaust ports, whereby exhaust gases from the previous engine cycle are purged from the cylinder by means of a flow created by a pressure differential between the open intake and exhaust ports, and working fluid flows at ambient pressure into the cylinder through the open intake ports; (v) Closing the open exhaust ports and returning the cylinder volume to V (vi) Closing the open intake ports and compressing the working fluid in the cylinders, by moving the pistons towards top dead center from cylinder volume V (vii) Metering a fuel charge of liquid hydrogen into the combustion volume V (viii) Metering a charge of water vapor into the combustion volume V (ix) Combusting the fuel charge in the combustion volume V (x) Expanding the cylinder volume from V (xi) Coupling the pistons to a cylindrical end-cam for imparting rotation thereto, whereby the cylindrical end-cam comprises a central axis and a cam profile having a compression segment setting the length of the compression stroke, the compression segment followed by a dwell segment setting the dwell time of the pistons at top dead center, the dwell segment followed by a power drive segment setting the length of the expansion stroke, said power drive segment having a first portion and a second portion that is contiguous with said first portion, wherein the first portion of the power drive segment is substantially parallel to the central axis of the cylindrical end-cam to provide for rapid piston acceleration in a first portion of the expansion stroke, and the second portion of the power drive segment possessing a curvature whereby the slope of the power drive segment smoothly transitions from being substantially parallel to the central axis of the cylindrical end-cam to being substantially perpendicular to the central axis to gradually engage the piston force for converting the linear piston motion to rotary motion of the engine in a second portion of the expansion stroke, said power drive segment and said compression segment configured such that the expansion stroke length of the piston is longer than the compression stroke length of the piston.