Alphonse C. Vassallo, of California, built his cylindrical cam Stirling engine in 1996. (Courtesy of Cherise Vassallo, Ingrid Vassallo, Andre Vassallo). The axial engine (also called cam, swashplate or barrel engine) is a type of reciprocating engine that replaces the common crankshaft with a circular plate. The pistons press against the plate in sequence, forcing it to rotate around its center. in Al’s engine, the plate has a channel machined around its circumference to capture ball bearings attached to shafts so the reciprocating pistons not only push, but also pull against the cam, forcing it to rotate around its center. The key advantage of the design is that the cylinders are arranged in parallel around the edge of the cam resulting in a very compact cylindrical shaped engine. The engine is 23″-long, 7″-wide, 8″-high, and 17 lbs.

Mr. Vassallo was awarded US Patent # 6,701,709 for his “Cylindrical Cam Stirling Engine Drive” in 2004.

Exhibit added: July 1, 2009 - Last modified: March 16, 2023

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