Considerations on Engine Design and Fuelling Technique Effects on Qualitative Combustion in Alcohol Diesel Engines.
Paper in proceeding, 1998
The paper depicts the main topics of the experimental investigation on alcohol engine development field, aiming at the engineering targets for the emission levels. The first part of this study was focused on engine design optimization for running on ethanol mexed with poly-ethylene glycol (PEG) as ignition improver. It was shown that some design changes in compression ratio, turbine casing, injector nozzle configuration and exhaust pressure governor (EPG) activation, lead to a better engine thermodynamics and thermochemistry. The second objective of this study was the investigation of engine performance and enmission levels, when the ignition improver diethyl ether (DEE) would be generated on board via catalyticallly dehydration of ethanol, and used directly as soluble mixture or separately fumigated. Both alternatives: ether fumigation technique and dissolved ether in alcohol fuel application were conceptually analyzed, and a stand up system based on DEE fumigation was used to determine the optimum DEE-ethanol ratio at any engine operating range. The heat release investigation, when the engine was run on neat ethanol and optimum fumigated DEE, has been indicated earlier combustion, and very short ignition delay. Verified possibilities for using DEE as ignition improver, would lead to a proper version of the on board ether reactor design, which would bring to another solution for ethanol fuelled engines.