REDUCTION OF POLLUTANTS IN CI ENGINE USING EMULSION FUELS TO REDUCE OVERALL TRAFFIC-INDUCED EMISSIONS
Diesel passenger vehicles will require over a 90 percent reduction in NOx and a 75 percent reduction in Particulate Matter to meets the new emission standards over the next few years. Such a large technical challenge will require a systems-based approach combining water emulsion and additives. The emissions improvement achieved by properly designed fuel-water emulsification is universal regardless of engine. The primary benefit of water-fuel emulsions in diesel engines is a notable reduction in NOx emissions. The added water acts as a diluent, which lowers the combustion temperature and suppresses NOx formation. The water emulsification decrease overall particulate emissions. Diesel water emulsification may require additional cetane enhancing additives. NOx can roughly be lowered on one- percent reduction of for every percent of water added to the fuel, depending on engine design and service profile. This reduction is achieved by lowering the peak combustion temperature in the engine cylinders. Better fuel atomization and more complete combustion serve to offset any reduced thermal efficiency from the quenching effect of water during the combustion process. The net impact on engine power development and fuel economy is minimal. This paper describes the fundamental approaches, water-diesel emulsion preparation, monitoring emulsion stability, retention period and corrosion testing to utilizing water fuel emulsions. This paper also describes the analysis of particle size and its effect.
