Study of the compression cycle of a reciprocating engine through the polytropic coefficient

The polytropic coefficient during the compression cycle of a reciprocating IC engine depends on the instantaneous values for pressure and volume, as well as on their variations. This dependency makes it useful to solve uncertainties typical of the engine experimental tests, such as the synchronization of pressure and volume signals. Additionally, knowledge of the polytropic coefficient is useful if the heat flux transferred to the walls is to be calculated, this variable being difficult to obtain either from modelling or from measurements, or to minimize errors on the estimation of geometric parameters such as the compression ratio.