Counterrotating cam and follower apparatuses (C-CAFA) capable of converting reciprocating to rotational motion, and visa versa, utilizing counterrotating cams cooperating with at least one reciprocating cam follower. Apparatus cam counterrotation is ensured to be synchronously timed without necessity of prior art stationary geartrains, by and through apparatus cam follower(s) combining with counterrotating cam surfaces acting as moving follower constraints, provided that disclosed structural limitations, including those regarding cam and follower surface interface engineering slop, multiple degree of freedom cams, rotating and reciprocating follower(s), and electromechanical limitations are met when specified. Optional apparatus usages include reciprocating mass balancer, differential to reverse and or multiply shaft rotations, and apparatus combinations with connecting rods, pistons, cylinders, and or engines. Adequacy of Constraint and Newtonian Force Analysis, Cam and Follower Surface Kinematical Analysis, and Electromagnetic Cam Analysis are applied to various disclosed embodiments to teach making, using, and correlation of disclosed apparatus structure to function.

A radial cam engine with an optimized cam configuration can provide improve performance over crankshaft internal combustion engines. The cam configuration can include a flat-top or flat bottom piston motion, multiple lobe cam configurations, matching piston force with torque/force ratio in combustion phase, asymmetry piston motions for improved power transfer during combustion phase, and/or offset piston and cam configurations. The radial cam engine can be used in vehicles, such as hybrid vehicles.

A hot fluid expansion engine has a plurality of actuator modules arranged in a star configuration around a central shaft. Each module includes a drive piston defining a working chamber of variable volume in the first enclosure; a movable displacement piston subdividing a second enclosure into a low temperature chamber of variable volume and a high temperature chamber of variable volume with the high temperature chamber communicating with a unit of a fluid heater device and the low temperature chamber communicating with the working chamber; and a fluid circulation circuit extending between the fluid heater device and the working chamber. The drive piston and the displacement piston of each actuator module are connected to the central shaft via respective first and second eccentric transmission devices suitable for imparting reciprocating motion in translation to each of the pistons with a phase lag of 90.

The radial cam engine described consists of a piston assembly arranged in a radial configuration. Within the engine, a piston moves back and forth within a cylinder during the internal combustion process. The piston is connected to a follower that is guided and interacts with a central cam. This central cam is responsible for turning a drive shaft. The radial cam incorporates three different cam profiles, each designed for a specific stage of the engine's operation. These profiles are specifically tailored for the compression stroke, combustion stroke, and exhaust stroke. By utilizing distinct cam profiles for each stroke, the engine can optimize its performance throughout the entire combustion process.