Abstract: An actuating mechanism for adjusting the swashplate angle in a Stirling cycle engine. A stationary mounted motor is used to drive one member of a planetary gear set. The motion of this member is transmitted through a second planetary gear set to a member connected to the swashplate. In one embodiment, a worm gear powered by a stationary mounted electric motor drives a moveable rear ring gear. The movement of the rear ring gear is transmitted through three rear planet gears and a common sun gear to produce relative movement in a front planet gear carrier. The relative movement of the front planet gear carrier is transmitted through a bevel gear to the swashplate. This embodiment allows the off-line production of swashplate actuator subassembly cartridges that can quickly be journalled to the drive shaft, joined to and properly phased with respect to the swashplate and meshed with a worm gear connected to the stationary electric motor during the assembly of a Stirling engine.

Abstract: A pressure relief system for a multi-cylinder heat engine, such as a multi-cylinder Stirling engine, having at least two essentially discrete working gas volumes which experience out of phase cyclical variations in pressure during operation of the engine, to reduce the likelihood of damage to the components of the engine in the event of severe pressure imbalance conditions developing within the engine. A spool positioned within a cavity in a housing has a closed position and an open position. In the event of a severe pressure imbalance condition, the spool is moved to the open position, the working gas volumes are allowed to communicate and the engine is unloaded.