As a way of the fuel design, the emulsified fuel which is formed by mixing the water or hydrophilic material with the surfactant to the hydrophobic fuel is studied .
The types of such emulsified fuel include the water in oil and oil in water, the former shows higher portion of the fuel than the latter.
Water molecules are in the diesel fuel as the form of particle and it hold the value in the aspect of preventing the corrosion by avoiding the direct contact with the inner wall of cylinder.
The emulsified fuel leads to evaporation of the water in the cylinder when applied to the engine and thus there is less chance of NOx generated from high temperature because latent heat is required for the evaporation of water.
Also, the evaporation of the emulsified fuel allows dispersion of large-sized fuel droplet by atomization improvement from microexplosion due to the rapid evaporation of water.
It is expected that the NOx and soot generations known as the trade-off may be decreased at the same time by applying the emulsified fuel to the internal combustion engine.
Therefore, research in terms of the emulsified fuel is conducted about droplet, spray and engine test.