On cycle-to-cycle heat release variations in a simulated spark ignition heat engine

• Published in: Applied energy 2011-05, Vol.88 (5), p.1557-1567
• Main Authors: Curto-Risso, P.L., Medina, A., Calvo Hernández, A., Guzmán-Vargas, L., Angulo-Brown, F.
• Format: Article
• Language: English
• Subjects: Applied sciences; Combustion; Combustion. Flame; Computer simulation; Cycle-to-cycle variability; Eddies; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Equivalence ratio; Exact sciences and technology; heat; Non-linear dynamics; Nonlinearity; Position (location); Quasi-dimensional simulations; seeds; Spark ignition engines; Spark ignition engines Cycle-to-cycle variability Quasi-dimensional simulations Non-linear dynamics; Theoretical studies; Theoretical studies. Data and constants. Metering; time series analysis; Turbulent combustion
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2010.11.030

The cycle-by-cycle variations in heat release are analyzed by means of a quasi-dimensional computer simulation and a turbulent combustion model. The influence of some basic combustion parameters with a clear physical meaning is investigated: the characteristic length of the unburned eddies entrained within the flame front, a characteristic turbulent speed, and the location of the ignition kernel. The evolution of the simulated time series with the fuel–air equivalence ratio, ϕ, from lean mixtures to over stoichiometric conditions, is examined and compared with previous experiments. Fluctuations on the characteristic length of unburned eddies are found to be essential to simulate the cycle-to-cycle heat release variations and recover experimental results. A non-linear analysis of the system is performed. It is remarkable that at equivalence ratios around ϕ ≃ 0.65, embedding and surrogate procedures show that the dimensionality of the system is small.