INFLUENCE OF CYCLIC WALL-TO-GAS HEAT TRANSFER IN THE CYLINDER OF THE VALVED HOT-GAS ENGINE

The valved hot-gas engine (VHGE), first reported at the 1973 IECEC is a closed regenerative, reciprocating Brayton cycle engine using helium as the working gas. Preliminary analysis shows that this engine is competitive with the Stirling engine in terms of low pollution, high efficiency, and power density. The low efficiencies of the first one cylinder engine have been under investigation since 1972. Tests and analyses show that cyclic heat transfer between the gas and the cylinder causes the major loss rather than piston ring leakage as first suspected. Engine efficiency could approach the expected 47% by further reduction of cyclic heat transfer in both the expander and the compressor.