Engine Design Optimization, a Practical Technology for Optimum Performance and Emissions of an Ethanol Fuelled Engine

Artikel i vetenskaplig tidskrift, 1997

Ethanol, as a very attractive fuel, has been available and studied for years, but being unsutable for most of the diesel engines, is not yet used as primary fuel. However, the engine design optimization, which is discussed in this paper, is found to be a practical technology in order to faciltate the ignition, enhance initial combustion rate and to reduce the emission levels. An acohol engine is expected to be less hot than conventional diesel, hence over penetration might give impingement of liquid fuel on piston crown, which could increase emission of unburned fuel and partially burned species CO. In order to predict the fuel spray impingement and to find the optimum injectors position, a simplified model for the spray tip penetration versus time was performed related to the piston position and injection duration. Also, combustion chamber of reentrant type and straight side wall bowll in-piston type were discussed and tested to prevent the physical reasons for HC and CO formation. Regulated and unregulated emissions were measured according to the different instrumentation as FID, NDIR,CHL,GC,MS using conventional sampling, dinitrophylhydrasine filters,and contaminated distilled water as well. In order to gain acceptance from the public for the ethanol engines with oxidation catalysts, and to increase the understanding of important phenomena in low temperature oxidation of fuels, a substantial information on ethanol oxidation catalysts performance was experienced and possible optimization is discessed.