Optimal heat release shaping in a reactivity controlled compression ignition (RCCI) engine

[EN] The present paper addresses the optimal heat release (HR) law in a single cylinder engine operated under reactivity controlled compression ignition (RCCI) combustion mode to minimise the indicated specific fuel consumption (ISFC) subject to different constraints including pressure related limits (maximum cylinder pressure and maximum cylinder pressure gradient). With this aim, a 0-dimensional (0D) engine combustion model has been identified with experimental data. Then, the optimal control problem of minimising the ISFC of the engine at different operating conditions of the engine operating map has been stated and analytically solved. To evaluate the method viability a data-driven model is developed to obtain the control actions (gasoline fraction) leading to the calculated optimal HR, more precisely to the optimal ratio between premixed and diffusive combustion. The experimental results obtained with such controls and the differences with the optimal HR are finally explained and discussed.This work was supported by Ministerio de Economía y Competitividad through Project TRA2016-78717-R.Guardiola, C.; Plá Moreno, B.; García Martínez, A.; Boronat-Colomer, V. (2017). Optimal heat release shaping in a reactivity controlled compression ignition (RCCI) engine. Control Theory and Technology. 15(2):117-128. https://doi.org/10.1007/s11768-017-6155-5S117128152F. Payri, J. M. Luján, C. Guardiola, et al. A challenging future for the IC engine: New technologies and the control role. Oil & Gas Science and Technology–Revue D IFP Energies Nouvelles, 2015, 70(1): 15–30.H. Yanagihara, Y. Sato, J. Minuta. A simultaneous reduction in NOx and soot in diesel engines under a new combustion system (Uniform Bulky Combustion System–UNIBUS). Proceedings of the 17th international Vienna Motor Symposium, Vienna, 1996: 303–314.D. A. Splitter, M. L. Wissink, T. L. 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A tool for predicting the thermal performance of a diesel engine

This paper presents a thermal network model for the simulation of the transient response of diesel engines. The model was adjusted by using experimental data from a completely instrumented engine run under steady-state and transient conditions. Comparisons between measured and predicted material temperatures over a wide range of engine running conditions show a mean error of 7◦C. The model was then used to predict the thermal behavior of a different engine. Model results were checked against oil and coolant temperatures measured during engine warm-up at constant speed and load, and on a New European Driving Cycle. Results show that the model predicts these temperatures with a maximum error of 3◦C.Torregrosa, AJ.; Olmeda González, PC.; Martín Díaz, J.; Romero Piedrahita, CA. (2011). A tool for predicting the thermal performance of a diesel engine. Heat Transfer Engineering. 32(10):891-904. doi:10.1080/01457632.2011.548639S891904321