Abstract: A five-cycle internal combustion engine in which the transfer cycle movements of the inlet and outlet pistons in the first cylinders are accompanied by a generally equal and axially opposite transfer cycle movement of the inlet and outlet pistons in the second cylinders so that all transfer cycle movements are axially balanced. Also disclosed is an improvement providing a compression ratio adjusting system constructed and arranged to effect axial movement between the cooperating inlet and outlet cams so as to vary the spacing between the inlet and outlet pistons in each cylinder at the combustion position thereof so as to vary the minimum volume condition defined thereby in relation to the volume defined by the compression position thereof.

Abstract: A five-cycle internal combustion engine in which a plurality of first cylinders and a plurality of second cylinders, having axes disposed in annularly spaced relation about the longitudinal axis of the housing assembly, and in annularly spaced relation with respect to one another. The inlet and outlet end portions of the first cylinders are arranged in axially opposite relation with respect to the inlet and outlet end portions of the second cylinders respectively. The first and second inlet and outlet cams associated with the first and second cylinders respectively are related to each other so that the transfer cycle movements of the inlet and outlet pistons in the first cylinders are accompanied by a generally equal and axially opposite transfer cycle movement of the inlet and outlet pistons in the second cylinders so that all transfer cycle movements of the first and second inlet and outlet pistons and the associated first and second inlet and outlet cam followers are axially balanced.