Abstract: A gear set is disclosed having a guide, such as a cam, engaging the output shaft of the gear shaft and being indexed thereby. The guide drives one or more followers which in turn drive one or more interfaces of a differential gear set. The output shaft may be driven by a third interface of the differential gear set. The followers may likewise engage piston assemblies in order to control the piston assemblies during execution of a process such as a four stroke combustion process, or other process involving compression or expansion of a gas. The piston assemblies are enclosed within a housing defining an annular chamber, such as a toroid. Apertures formed in the housing allow exhaust gases to leave and air to be taken in. In one embodiment, a hyper expansion port is formed in the housing to release a portion of the air during the compression stroke in order to decrease the pressure of combustion gases.

Abstract: Actual slip is determined from deviation of measured speeds of traction drive elements and known "no-slip" ratio for the drive ratio settings of a traction drive transmission. An error signal is generated whenever the relationship between the foregoing actual slip and traction pressure is outside defined limits to correct traction pressure as a function of the error signal.

Abstract: Power is transmitted through a low torque power path established by a variable traction drive assembly to control the drive ratio of a plural power path, constant mesh gear transmission. The contact pressure associated with the traction drive assembly is varied as a function of the transmission drive ratio that is varied between reverse and forward drive values under control of the traction drive assembly.

Abstract: A variable diameter traction roller is connected in line with high torque transmitting gearing of the planetary type to control the over-all transmission drive ratio through an axially shiftable, driven traction roller. The driven traction roller is mounted on a pivotally displaceable bracket through which a tension device exerts a variable contact force and the pitch line angle between traction rollers is varied by a limited amount.