<div>The article presents a hybrid concept of a turboshaft engine that fits into the
area of PGE (pressure-gained combustion). It combines the advantages and
elements of a piston engine and a turbine engine. The combustion takes place in
isochoric chambers. The proposed timing system of the engine efficiently
realizes the Humphrey cycle. Additionally, the main gas cycle engine was
enhanced by the Clausius–Rankine steam cycle to achieve effective power of
engine equal to 1231.3 kW. It was supplied by waste heat recovery from the
exhaust gas. The enhancement of the engine by the secondary steam cycle
significantly improved engine effective efficiency with a final value reaching
0.446. The effective efficiency and specific fuel consumption of the engine were
calculated using merged analytical–numerical CFD (computational fluid dynamics)
analysis. The centrifugal compressor, gas turbine, and steam turbine can work on
the common shaft whose rotational velocity is 35,000 rpm. Because of additional
weight, it could have potential applications for stationary use or heavy
military units.</div>