Analytical and Experimental Investigation of Ringless Piston Concept
Final rept. Sep 86-Nov 87
SOUTHWEST RESEARCH INST SAN ANTONIO TX
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The purpose of this project was to analytically and experimentally investigate the concept of a ringless piston internal combustion engine. A joint objective was to design, build, and test a ringless piston to improve ringless piston engine performance. A computer model was developed to predict ringed and ringless piston engine performance. Experimental performance data were then collected by operating a small, liquid-cooled, two-stroke gasoline engine with and without the piston ring on the stock aluminum and Southwest Research Institute prototype steel piston. The experimental performance data were then compared with the results of the computer model. The results showed that a piston engine can operate without piston rings. Ringless piston engine power and efficiency were found to be defined by the expression CNBS, where C piston- to-bore diametrical clearance, N engine speed in rpm, B engine bore, and S engine stroke. There was good agreement between predicted and measured performance reperformance can be improved by using piston and liner materials that have similar coefficients of thermal expansion. Keywords Engine, Piston, Piston ring, Compound engine, Reciprocating engine, Ringless piston.
- Reciprocating and Rotating Engines