Studying combustion and cyclic irregularity of diethyl ether as supplement fuel in diesel engine

CATEGORY: DIESEL
Fuel, Volume 109, July 2013, Pages 325–335
Studying combustion and cyclic irregularity of diethyl ether as supplement fuel in diesel engine
D.C. Rakopoulos, C.D. Rakopoulos, E.G. Giakoumis, A.M. Dimaratos
Internal Combustion Engines Laboratory, Department of Thermal Engineering, School of Mechanical Engineering, National Technical University of Athens (NTUA), Zografou Campus, 9 Heroon Polytechniou St., 15780 Athens, Greece
Abstract
Authors studied the effects of using diesel fuel blend with diethyl ether (DEE) 24% by vol., a promising fuel that can be produced from biomass (bio-DEE), on the combustion behavior of a standard, direct injection, ‘Hydra’ diesel engine. They were able to produce combustion chamber and fuel injection pressure diagrams at four loads, using a high-speed, data acquisition and processing system. A heat release analysis of the cylinder pressure diagrams and plots of histories in the combustion chamber of the gross heat release rate (HRR) and other related parameters, reveal some interesting features of the combustion mechanism when using DEE blend.
Cylinder pressures and temperatures are reduced, HRR diagrams are delayed, and the engine runs somewhat leaner at reduced heat losses, with the DEE blend vs. neat diesel fuel for all loads. Furthermore, given the shown low ignition quality of DEE/diesel fuel blend and reports for unstable engine operation at high DEE blending ratios, authors explored the strength of cyclic irregularity as reflected in the pressure indicator diagrams, by analyzing for the maximum pressure and rate as well as dynamic injection timing and ignition delay, using stochastic analysis for averages, coefficients of variation, probability density functions, auto-correlations, and cross-correlation coefficients. The stochastic analysis reveals the randomness of fluctuation phenomena observed in the engine, and the cross-correlation coefficients showed that neither the injection process nor the DEE/diesel fuel blend had a marked effect on cyclic irregularity.
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