Analysis of unrestrained curve of rectangular piston ring based on energy principle

A rotary engine with rectangle pistons and cylinders is claimed to have higher mechanism efficiency for eliminating the lateral force between piston skirt and liner. Constrained by the present machining and assembly accuracy, surfaces of piston could not fit the internal surface of cylinder well which might lead to gas leakage from cylinder. A novel ring used to seal rectangular cylinder was invented, and the working theory of the piston ring was present. Then based on the assumption of uniform pressure distribution on the contact surface of the ring the mathematical model of unrestrained curve of the ring was established. The modeling process was present in detail. Furthermore a finite element analysis was carried out as a way to validate the mathematical model of the piston ring. Results show that deformation of piston ring achieved from calculation and simulation meets well at initial and ending segments. The maximum error appears in the middle segment, which is only 11.52%. The accuracy of mathematical model is acceptable.