Search Results

This work regards the study of the effect of the fuel properties on the diesel engine emissions of particulate separated in soluble organic fraction (SOF) and soot. A Euro-4 engine was used operating at two engine conditions: 1500 rpm speed − 8% of maximum load and 2300 rpm − 13%. Model hydrocarbon fuels containing 100% of n-alkanes and iso-alkanes were used for studying the effect of cetane number. The effect of fuel composition on soot and SOF emissions was studied at a fixed cetane number (52) by using six fuels formulated with 90 vol% of model alkanes and iso-alkanes and 10 vol% of different components as alkylbenzenes, naphthenes (decaline), diaromatics (methylnaphthalene), fatty acid methyl esters (FAME) and highly paraffinic refinery streams (Fischer-Tropsch GtL and high-pressure Hydro cracking).

The aim of this study is to investigate how the fouling that injectors undergo after several operating hours on a vehicle can affect the injection and combustion phases. The impact of the injector fouling on the pollutant formation has been also investigated. Moreover, the effects of the injector cleaning by deposits through the top quality diesel fuel commercialized by eni that is FAME free and contains multi performance additives have been investigated. The experimentation has been carried out on transparent compression ignition engine. It is a single cylinder equipped with a Euro 5 multi-cylinder head and a second-generation common rail injection system. Three indirect-acting piezoelectric injectors have been tested. The first one has been fouled with European commercial diesel fuel through the CEC DW10 injector-coking test. The second one has been fouled in the same way and, then, it has been cleaned with eni top quality diesel fuel. This fuel has fed the third injector too.

Polyoxymethylene dimethyl ether (POMDME) is a new alternative fuel that can be produced from waste biomasses and tailored through the distribution of oligomers to fit into the distillation range of diesel fuel. Since one potential advantage of alternative fuels is that they could reduce emissions also from old in-use vehicles without waiting for their replacement, we have measured and evaluated the emission performance of neat POMDME and a blend of 10% POMDME and 90% commercial diesel fuel in an old Euro-2 diesel car over the NEDC driving cycle. As compared to the reference diesel fuel, the experimental results show a significant reduction in PM emissions already with the 10% blend, i.e., −18%, and even more pronounced with the neat POMDME, i.e., −77%. With this latter the PM emission reached below the Euro 4 limit. The composition of PM was quite different for the two extreme fuels; being mostly VOF from lube oil for the neat POMDME, while mostly soot in the case of diesel fuel.