Research on Extended Expansion General-Purpose Engine-Efficiency Enhancement by Natural Gas Operation-

Research on extended expansion engine was carried out in order to enhance thermal efficiency in general purpose engines. A four-jointed linkage was used between the connecting rod and the crank pin of a standard piston-crank system and provides an Atkinson thermo dynamic cycle.

Thermal efficiency of an engine with a compression ratio of 12.4 and an expansion ratio of 18.1 was compared to an engine with a compression ratio of 9.4 and an expansion ratio of 13.6.

Measured indicated thermal efficiency of prototyped engine operated by natural gas was 38.7%, a 2.6% increase, as predicted in the numerical simulation.