Preparation of emulsion
A mixture of diesel, water, surfactant were circulated several times to form an emulsion using an apparatus comprising of a centrifugal pump, glass jar and glass tube with a submergible nozzle portion as shown in Fig. 2. As oil soluble surfactant (HLB < 10)are the best for water-in-oil emulsions, the surfactant with HLB of 7 was used for preparing the emulsion. The surfactant used was 1% by weight and stability time for the emulsion was about one and half days. After the emulsion prepared in off-line, then it was immediately used in the engine.