Abstract: This invention is an electric unicycle. It is an improvement of a unicycle and a self-balancing electric unicycle. It comprises one wheel (1B), brushless DC motor (1C), operating-pedal (1D), seat (2A), pneumatic springs (2B) for shock absorb, mainboard (1F), lithium-ion battery pack (1G), telescopic handle (1I), emergency brake footboard (1J), casing (1H). The emergency brake footboard (1J) can be easily mounted and unmounted and folded. While in using, the user generally rides on the seat, swings their foot, to adjust the depression angle of the operating-pedal (1D), to control the wheel rotation, rather than by an electric gyro. Thus, this invention is easy to operate, easy to learn, easy to use, flexible, portable, zero emission, great trafficability. It will become the main short-distance means of transportation for cities and villages, and even can be used in poor road conditions, such as field exploration and forest patrol.

Abstract: An internal combustion engine featuring a radial array of cylinders and pistons; the pistons having rods including cam followers engaging the surface of a cam drive to transfer reciprocating linear motion into rotary motion; wherein between the piston rods and the engine housing are disposed arrays of toothed rollers to provide a rolling interface.