2. Classification scheme for non-conventional engines

A positive-displacement internal combustion engine converts the energy released by combustion into mechanical energy on its output shaft. Typically, the oxidizer is taken from the ambient atmosphere, undergoes a succession of transformations within the capsulism, and is then expelled back into the atmosphere. The appropriate introduction of a liquid or gaseous fuel into the combustion air results in the combustion of the reactive air-fuel mixture according to the mixed thermodynamic cycle at constant volume and pressure within the capsulism itself. The rectilinear reciprocating motion of the piston is transformed into circular motion of the crankshaft via the usual connecting rod-crank kinematics.

A conventional piston engine is thus an aerobic, reciprocating, internal combustion engine in which the combustion of a reactive air-fuel, liquid...