Piston with floating flame damper ring - comprises material of lower expansion coefficient than cylinder held in clearance fit at top of piston

摘要

The engine piston has a groove above the piston-ring groove or grooves for seating a flame damper ring of low expansion material. The clearance existing between the ring and the bottom of the groove allows the clearance to be maintained at a steady state of the engine. This clearance is within the minimum limit to avoid seizing of the piston in the bore. The piston ring pref. has a relatively small radial thickness, being conformed not to close on the tips when subjected to high stress but to act on the bottom of the groove.