Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas

• Published in: Applied thermal engineering 1999-05, Vol.19 (5), p.513-529
• Main Authors: Lapuerta, M., Armas, O., Hernández, J.J.
• Format: Article
• Language: English
• Subjects: Applied sciences; combustion process; diesel engines; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; experimental diagnosis; Thermodynamic properties
• ISSN: 1359-4311
• DOI: 10.1016/S1359-4311(98)00075-1

Combustion diagnostic methods based on the in-cylinder pressure signal are extensively used for calculating the heat release law or the burned fuel mass as well as the mean gas temperature from combining both the first principle of thermodynamics and the state equation. In both equations the instantaneous gas composition has great influence, even through the internal energy or through the gas constant. In the proposed method the gas is supposed to be composed of pure air, gaseous fuel and products of a stoichiometric combustion, neglecting the effect of local conditions (local mixing ratios and temperatures), but including their bulk temperature dependence. The concentration in the gas of each of these species was related with engine test parameters. A thermodynamic approach, coherent with the mentioned species distinction, is also proposed. The results of temperature correlations of the main thermodynamic properties are presented, as well as some results of the combustion diagnostic procedure from engine tests with different exhaust gas recirculation ratios.