Abstract: A variable-stroke reciprocating internal combustion engine, the engine having an engine shaft and a piston configured to reciprocate within a cylinder chamber having an axis, each piston having a first piston part operable to move in unison with or separately from a second piston part to define piston strokes for different thermal functions of the engine, includes an assembly pivotally coupled to the first piston part at a copy point and an actuator coupled to the assembly, wherein the actuator is operable to control motion of the assembly to thereby define substantially linear movement of the copy point along the cylinder chamber axis.

Abstract: A method of establishing and maintaining a piston compression height during portions of a combustion cycle in a differential-stroke cycle combustion engine, includes providing a piston seat cup coupled to said first piston part and a piston seat cover operatively associated with said piston seat cup and defining a sealed piston seat cavity, abutting said second piston part with said piston seat cover and moving said piston seat cover relative to said piston seat cup, aligning a fluid ingress aperture with a cooperating piston rod passage and piston pin inlet for a portion of said combustion cycle thereby allowing fluid to enter said piston seat cavity, and aligning a fluid egress aperture with a cooperating piston pin passage and piston rod outlet for a portion of said combustion cycle thereby allowing fluid to exit said piston seat cavity.

Abstract: An apparatus and method for a differential stroke combustion engine. The combustion engine including one or more two-part pistons, each two-part piston having a first piston part and a second piston part. The apparatus comprising: piston-lever element mechanically coupled to the second piston part; a plurality of cam-followers assemblies selectively coupleable with the piston-lever element for controlling operation of the second piston part; and wherein selective engagement of one or more cam-followers assemblies defines an operational mode of the second piston part.

Abstract: A differential stroke reciprocating internal combustion engine having an engine shaft and a piston configured to reciprocate within a cylinder chamber includes an inner piston part, a piston stem coupled at a first end to said inner piston part, an outer piston part which serves as a carrier for said inner piston part and is connected to said engine shaft, wherein said inner piston part is configured to operate on a cycle different from that of said outer piston part, and a control and linkage assembly coupled to said engine at an anchor point, and said control and linkage assembly pivotally coupled at a second end of said piston stem defining a copy point, wherein said control and linkage assembly guides and defines the movement of said copy point to be substantially aligned with an axis of said cylinder chamber.

Abstract: A method of establishing and maintaining a piston compression height during portions of a combustion cycle in a differential-stroke cycle combustion engine, includes providing a piston seat cup coupled to said first piston part and a piston seat cover operatively associated with said piston seat cup and defining a sealed piston seat cavity, abutting said second piston part with said piston seat cover and moving said piston seat cover relative to said piston seat cup, aligning a fluid ingress aperture with a cooperating piston rod passage and piston pin inlet for a portion of said combustion cycle thereby allowing fluid to enter said piston seat cavity, and aligning a fluid egress aperture with a cooperating piston pin passage and piston rod outlet for a portion of said combustion cycle thereby allowing fluid to exit said piston seat cavity.

Abstract: A piston seat method and apparatus for a differential-stroke cycle combustion engine, the combustion engine including one or more two-part pistons, each two-part piston having a first piston part and a second piston part. The apparatus comprising: a piston seat cover operatively associated with the first piston part, the piston seat cover being adapted for abutting engagement with the second piston part; wherein, upon abutting engagement, the seat cover is adapted to move relative to the first piston part, thereby at least partially absorbing impact forces applied between the first piston part and the second piston part.

Abstract: A differential stroke reciprocating internal combustion engine having an engine shaft and a piston configured to reciprocate within a cylinder chamber includes an inner piston part, a piston stem coupled at a first end to said inner piston part, an outer piston part which serves as a carrier for said inner piston part and is connected to said engine shaft, wherein said inner piston part is configured to operate on a cycle different from that of said outer piston part, and a control and linkage assembly coupled to said engine at an anchor point, and said control and linkage assembly pivotally coupled at a second end of said piston stem defining a copy point, wherein said control and linkage assembly guides and defines the movement of said copy point to be substantially aligned with an axis of said cylinder chamber.

Abstract: An apparatus and method for a differential stroke combustion engine. The combustion engine including one or more two-part pistons, each two-part piston having a first piston part and a second piston part. The apparatus comprising: piston-lever element mechanically coupled to the second piston part; a plurality of cam-followers assemblies selectively coupleable with the piston-lever element for controlling operation of the second piston part; and wherein selective engagement of one or more cam-followers assemblies defines an operational mode of the second piston part.