Microemulsion fuels, tested

The test shows that the emulsifier has a negative eflFect on the ignition performance and that this eflFect is further enhanced by adding water. However, an important diflFerence was noted. With microemulsion fuels, the NOa, content of the exhaust gases was reduced substantially while with the emulsion fuels, the detected amount of NO, increased considerably. 

The engine used was a one-cylinder direct-injection test engine at Saab-Scania, Sodertalje, Sweden. During the tests, maximum pressure, fuel consumption, exhaust temperature, CO, CO2, NO, NO2, O2, HC, and smoke were registered at varied injection timings, loads, and speeds. The performance of three microemulsion fuels was compared with a reference fuel of pure diesel oil with the cetane number of 43. The data of the microemulsion fuels are given in Table II. 

Another possible application where the typically low viscosity of microemulsions is very useful is in the preparation of alternative fuels for diesel engines. Such hybrid fuel microemulsions containing vegetable oil [13] and alcohols, with 1-butanol [14] or a lower trialkylamine [15] acting as surfactant attracted interest some years ago, and such systems were tested for their practical application [16]. Similar systems containing triglyceride, aqueous ethanol, and 1-butanol [17] or long-chain fatty alcohols [18] were also studied for the same purpose. 

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