doiSerbia

A quick, simplified approach to the evaluation of combustion rate from an internal combustion engine indicator diagram

Tomić Miroljub V. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Popović Slobodan J. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Miljić Nenad L. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Petrović Stojan V. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Cvetić Miloš R. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Knežević Dragan M. (Faculty of Mechanical Engineering, Department for Internal Combustion Engines, Belgrade)
Jovanović Zoran S. (Vinča Institute of Nuclear Sciences, Centre for Internal Combustion Engines and Motor Vehicles, Belgrade)

In this paper a simplified procedure of an internal combustion engine in-cylinder pressure record analysis has been presented. The method is very easy for programming and provides quick evaluation of the gas temperature and the rate of combustion. It is based on the consideration proposed by Hohenberg and Killman, but enhances the approach by involving the rate of heat transferred to the walls that was omitted in the original approach. It enables the evaluation of the complete rate of heat released by combustion (often designated as “gross heat release rate” or “fuel chemical energy release rate”), not only the rate of heat transferred to the gas (which is often designated as “net heat release rate”). The accuracy of the method has been also analyzed and it is shown that the errors caused by the simplifications in the model are very small, particularly if the crank angle step is also small. A several practical applications on recorded pressure diagrams taken from both spark ignition and compression ignition engine are presented as well.

Keywords: internal combustion engine, indicator diagram, rate of heat release