The problematics of determining the characteristics of heat release, based on experimental indicator diagram for diagnostic purposes

The article discusses the problem of determining the characteristics of heat release based on experimental indicator diagram for diagnostic purposes. The importance of the operational diagnosis of marine engines is the analysis of indicator diagrams was identified. In addition to analysing changes in the values of indicated, should be aimed to oriented broader analysis, including the determination on the basis of experimental indicator diagram of heat release characteristics during the combustion process. Then it is essential to choose the right model of heat release for reciprocating piston engines with direct fuel injection. In the diagnostics of piston engines, including marine engines, special interest arouses use single-zone model based on indicator diagrams as a source of information. Based on the results their own research we analysed the impact on the characteristics of heat release of simplifying assumptions in the model of heat release, including constant value adiabatic exponent. In the temperature, range 300÷2800 K waveformsκ are considered to be linearly dependent on the temperature. Based on the above, for the gas temperature from 800 K to 1850 K value of the exponent κ decreases about 3%. The effect of the value κ on the course of characteristics q and Q, to the typical marine engines was shown.