Image Number 15 for United States Patent #4738235.
A rotary engine has a first ring-shaped floor portion connected to an inner shaft for rotation therewith and a second ring-shaped floor portion connected to an outer shaft for rotation therewith. The annular floor portions cooperate with an engine casing to define an annular chamber. A first pair of diametrically aligned pistons are positioned within the annular chamber and are connected to the first ring-shaped floor portion while a second pair of diametrically aligned pistons are positioned within the angular chamber and connected to the second ring-shaped floor portion. The pistons cooperate to define a plurality of combustion chambers. Means are provided for causing combustion in the combustion chambers for imparting rotary motion to the inner and outer shafts. A first power transfer gear connected to the inner shaft transfers power to a drive shaft when the inner shaft is driven and a second power transfer gear connected to the outer shaft transfers power to the drive shaft when the outer shaft is driven. Unique piston seals, a controller for regulating the position of the pistons, and a novel lubrication system are also disclosed.