Oxygenated additives production for diesel engine emission improvement

This present paper evaluates the potentiality in terms of production method and pollutant emission reduction of a new bio-derived oxygenated compound, 1,1-diethoxyethane, used as additive in an automotive diesel engine. The additive is obtainable from bio-ethanol by means of an acid-catalysed process. Several acid ion-exchanged polymers with acidic strength comparable with that of “concentrated” sulphuric acid were used to prepare silica-perfluorosulfonic (PFS) acid catalysts by incipient wetness impregnation of commercial silica samples. The acid catalysts were used in the synthesis of acetal at 4°C and 3 atm in a stirred batch reactor. A systematic comparison of reaction path and catalysts acid-strength points to a direct relationship between acidic capacity and catalytic activity. The product has good characteristics for diesel blending, but it is characterized by a low flash point. The evaluation of the additive performance in a diesel fuel blend was carried out in a passenger car light-duty diesel engine in two steady-state operation points. The chosen testing points are considered partially representative of the engine behaviour during the NEDC test procedure. Engine tests showed an insensitive effect of 1,1-diethoxyethane on gaseous pollutant emissions (HC, CO and NOx), on the contrary a marked reduction of exhaust smoke was verified. Fuel consumption was slightly increased because of the total oxygen content of the blend.