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The increased use of alternative fuels has been linked to performance deterioration of injectors and engines as a result of internal diesel injector deposits (IDID). The present paper investigates fuel composition impact on injector tendency to blockage. Three main areas were investigated : (1) deposits linked to paraffins and aromatics content; (2) deposits linked to biodiesel composition using fatty acid methyl esters (FAME) and hydrotreated vegetal oil (HVO); and (3) deposits linked to the presence of additives (Dodecenylsuccinic anhydride DDSA, Dodecenyl Succinimid DDSI and Sodium Naphthenate). A deposit formation method was developed for the injection bench in order to discriminate the impact of fuels on system performance in terms of fuel volume injected, injection duration and stability. Three operation conditions were tested to represent low, intermediate and high load. In addition, the influence of soaking time and injector heating temperature was evaluated.

The increased use of alternative fuels has been linked to deterioration in performance of fuel injection systems as a result of insoluble deposit formation. Here, the impact of Diesel/biodiesel blends formulation and temperature on the oxidation stability was studied based on total acid number (TAN), density, viscosity and surface tension. We have compared fuel oxidation during storage with fuel oxidation into the fuel injection system (FIS) and determined the most important physical-chemical parameters that could be used to follow fuel oxidation on-board. Based on the results obtained, a satisfactory correlation between storage oxidation and fuel on-board degradation was observed. Biodiesel fuel tends to deteriorate during delivery and storage before refueling. Also, fuel ageing on-board is equivalent to 4-5months of storage which means Biodiesel has impact on fuel injection system with long-term storage/parking after high or high-low alternating load operation.

The use of biodiesel has risen worldwide in the last decade. Different countries use different biodiesel feedstocks which will depend on the resources available locally. Some problems due to biodiesel content and feedstock quality have been pointed out in the literature, which include cold flow properties issues of several methyl esters, especially Palm Methyl Ester (PME). The present work was carried out on diesel-biodiesel blends from 0 to 30%v/vPME in order to evaluate the impact of crystals formation on fuel filter plugging using a rig test. The fuel was maintained at 5°C and 20°C during soaking. The crystal particles formation was evaluated by the Turbiscan™ technique (based on multiple light scattering with near infra-red light), followed by particles mass weight determination by filtration. The fuel was then evaluated in the test rig until performances degradation in terms of fuel flow rate and filter pressure drop.

Current and future engine technologies and fuels are mutually dependent. The increased use of alternative fuels has been linked to deterioration in performance of injectors, fuel filters and engines as a result of insoluble deposit formation. The present work aimed to study the impact of Diesel/biodiesel blends formulation (biodiesel feedstock and content) and temperature on the oxidation stability based on total acid number (TAN). The biofuels used in the fuel matrix were: rapeseed, soy and palm methyl esters (RME, SME and PME respectively). The Diesel/biodiesel blends were made with 0%v/v, 5%v/v, 10% v/v and 20%v/v of biodiesel blended with additive-free new Diesel. The oxidation stability of Diesel/biodiesel blends was to evaluate during 6 months fuels storage, under 20°C and 40°C, and fuels severe oxidation into a reactor vessel to better understand the parameters leading to fuel oxidation on-board.

Air traffic has been steadily increasing for the last years. Moreover, fuel availability at a reasonable cost seems more and more uncertain. Climate change implies that greenhouse gases emissions should be reduced. In this context, the search for new alternative fuels for aircraft seems to be a promising solution. Nevertheless, aeronautic represents a very specific transportation mode, due to its usage (short range, middle range, long range with the same fuel, worldwide distribution of the fuel…) and its compulsory security constraints. In the first part of the European project ALFA-BIRD (Alternative Fuels and Biofuels for Aircraft development - FP7), a selection of the best candidates to become the fuels for the future of aircraft has been done. The selection process was very complex, due to multiple criteria (physical properties, economical issued, environmental issues…).