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To reduce the fuel related logistic burden, NATO Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment. To this end, F-34 is replacing distillate diesel fuel in many applications. Yet, unacceptable wear due to poor lubricity was illustrated by tests conducted with kerosene on High Frequency Reciprocating Rig. Therefore, HFRR tests were performed with fatty acid methyl esters of sunflower, palm, cotton-seed, tobacco-seed, olive, rape-seed and used frying oils, at volume concentrations from 0.05% to 0.6%. This study showed that the biodiesels used, produced a significant decrease in the wear scar diameter at concentrations of 0.2% to 0.4 %. Biodiesels derived from non-polyunsaturated oils, such as palm and olive gave better lubrication at certain concentrations.

In this study, the transesterification process of 4 different vegetable oils (sunflower, rapeseed, olive oil and used frying oil) took place utilizing ethanol, in order to characterize the ethyl esters and their blends with diesel fuel obtained as fuels for internal combustion engines. All ethyl esters were synthesized using calcium ethoxide as a heterogeneous solid base catalyst. The ester preparation involved a two-step transesterification reaction, followed by purification. The effects of the mass ratio of catalyst to oil, the molar ratio of ethanol to oil, and the reaction temperature were studied on conversion of sunflower oil to optimize the reaction conditions in both stages. The rest of the vegetable oils were converted to ethyl esters under optimum reaction parameters. The optimal conditions for first stage transesterification were an ethanol/oil molar ratio of 12:1, catalyst amount (3.5%), and 80 °C temperature, whereas the maximum yield of ethyl esters reached 80.5%.

The objective of this paper was to evaluate the performance and airborne emissions of a diesel-water emulsion in 4 public buses operated in the area of Athens. The fuels used were a typical automotive diesel from the Greek market, a low sulfur diesel and a diesel-water emulsion of 13 % v/v water in low sulfur diesel. The fuels were characterized by exposing their physicochemical properties according to EN 590. The measurements of emissions of carbon monoxide, unburned hydrocarbons and carbon dioxide did not show any significant differences among the three fuels. The effects on NOx emissions can be termed as mixed, bearing also in mind that they represent engine operation at no load. The beneficial effect of the emulsified diesel fuel could be readily observed in the case of smoke opacity emissions.

The present paper is an effort to evaluate ethanol in diesel fuel and its main alternatives. The fuels used were an ultra low sulfur diesel fuel containing 15% by volume gas-to-liquid (GTL), JP-5 and JP-8 fuels produced in Greece and biodiesel produced from animal fats. The fuels were tested for compliance to the respective specifications at the Fuels Laboratory of the National Technical University of Athens (NTUA). The test fuel matrix consisted of blends of 5-15 % by volume ethanol with diesel, JP-5, JP-8 and with mixtures of the above with 5% by volume biodiesel. The test fuels were used in a stationary single-cylinder diesel engine with indirect injection, in order to evaluate their performance and emissions under various loads.

The present paper aims to discuss the quality characteristics of Jet Fuels used in the Greek market in comparison with fuels used in other countries and to evaluate jet fuels along with diesel and biodiesel on a diesel engine. To establish the quality characteristics for Jet Fuels of the Greek market, fuel samples were collected from the local refineries on a regular basis, thus monitoring the fuel quality fluctuation over time. JP8, along with diesel and biodiesel, were used alone and in mixtures on a single cylinder stationary diesel engine. Emissions and volumetric fuel consumption were measured under various loads.

This work includes an assessment of the lubricity of Greek road diesel fuel of low sulfur content, and the effect of the addition of two different types of biodiesel which can be produced from raw materials abundant in the Mediterranean area. In this study, a series of representative fuels of the Greek fuel market were tested. In some of them, the lubricity was measured three times, during a period of three months from the day of each sample was produced. In all cases a decrease of the wear scar diameter (WSD) was measured; this behaviour could be attributed to the oxidation reactions that take place during the storage period. In order to monitor the effect of the addition of biodiesel on the lubricity of road diesel, biodiesels produced from sunflower oil and olive oil were used. The use of rape seed oil biodiesel as a diesel fuel substitute is a commercial event in Central Europe; in the United States the soybean oil biodiesel has been examined in detail.