Abstract: Diesel fuel is stored in a first fuel tank, while water is stored in a second fuel tank. To use an emulsion fuel, diesel fuel and water are mixed and are caused to enter an injection pipe through a junction located between an injection pump and an injection nozzle. The emulsion fuel is injected through the injection nozzle. The engine is also equipped with exhaust gas recirculation devices to return a portion of the exhaust gas of the engine to an intake pipe of the engine so that some of the exhaust gas is recirculated.

Abstract: The invention relates to an emulsion fuel engine which uses an emulsion fuel as a fuel and contemplates provision of an emulsion fuel engine which prevents inadvertent failure in starting caused by separation of emulsion fuel and deterioration of the durability of parts of an injection system and is reduced in production of NOx or soot and in specific fuel consumption. The emulsion fuel engine comprises a fuel injection pump for supplying a first fuel to a fuel injection nozzle, and emulsion fuel supplying means for supplying an emulsion fuel, which is obtained by emulsifying the first fuel and a second fuel which is insoluble to the first fuel, to an injection pipe between the fuel injection pump and the fuel injection nozzle.