Effects of Emulsified Fuel on Combustion in a Four-Stroke Diesel Engine

While the use of emulsified fuel in diesel engines has been an area of much research interest in recent years, the promising results reported in laboratories have not been easy to reproduce in commercial practice. Many of these studies have only measured external effects such as fuel consumption and exhaust emissions. A single-cylinder research engine was operated with water/diesel fuel oil and hydrous ethanol/diesel fuel oil emulsions of varying percentages. Crank angle, cylinder pressure and injector lift were recorded electronically over 50 engine cycles, permitting calculation of the mean and standard deviation of key combustion parameters. The results showed decreased fuel consumption and increased ignition delay, peak cylinder pressure and maximum cylinder pressure rise rate for emulsion operation. While the standard deviation data showed little change in cycle-to-cycle variation for wateremulsion operation, increases of over 200 percent were measured for operation at ethanol amounts over 20 percent.