Tribological Performance of Biomass-Derived Bio-Alcohol and Bio-Ketone Fuels

This study relates to developing future alternative fuels and focuses on the effects of a fuel’s molecular structure on its properties and performance in advanced propulsion systems. The tribological performance of various biomass-derived oxygenated alternative fuels, including butanol, pentanol, cyclopentanol, cyclopentanone, and gasoline and their blends with diesel, was investigated. Lubricity tests were conducted using a high-frequency reciprocating rig (HFRR). Cyclopentanone-diesel and cyclopentanol-diesel blends result in smaller wear scar sizes compared to using their neat forms. A lower steel disc contaminated with the alternative fuels during the HFRR tests resulted in worn surface roughness values lower than those of the neat diesel by up to 20%. It is believed that these reductions are mainly due to the presence of the hydroxyl group and the carbonyl group in alcohols and ketones, respectively, which make them more polar and consequently helps the formation of the protective lubrication film on the worn moving surfaces during the sliding process. Overall, the results from this study indicate that environmentally friendly cyclopentanol and cyclopentanone are practical and efficient fuel candidates for future advanced propulsion systems

The significance of low carbon bio-alcohols and bio-ketones fuels for clean propulsion systems

This experimental work investigates oxygenated bio-fuel component blends of butanol, pentanol and cyclopentanone with diesel on the combustion characteristics, gaseous emissions and particulate matter (PM). Furthermore, PM characteristics, including size distributions, morphology and nanostructure are investigated.The oxygen content on the sustainable fuel blend components (bio-alcohols and bio-ketone) and the lower cetane number leading to a longer ignition delay, larger premixed combustion phase and high mean peak combustion temperature reduced the total number of particle concentration by up to 91%. Characterisation of particles demonstrated morphological and nanostructural alterations, such as the reduction in primary particle size that would lead to greater particle oxidation reactivity. Furthermore, the combustion of oxygenated blends showed a reduction in the total hydrocarbon emissions and an increase in NO2 concentration. This research provides new knowledge to understand the effects of fuel properties on gaseous and particle emissions formation and characteristics. Overall this work demonstrates bio-alcohols and bio-ketones as low carbon fuels in unveiling strategies for vehicular emissions abatement

The characterisation of diesel exhaust particles - composition, size distribution and partitioning

A number of major research questions remain concerning the sources and properties of road traffic generated particulate matter. A full understanding of the composition of primary vehicle exhaust aerosol and its contribution to secondary organic aerosol (SOA) formation still remains elusive, and many uncertainties exist relating to the semi-volatile component of the particles. Semi-Volatile Organic Compounds (SVOCs) are compounds which partition directly between the gas and aerosol phases under ambient conditions. The SVOCs in engine exhaust are typically hydrocarbons in the C15–C35range, and are largely uncharacterised because they are unresolved by traditional gas chromatography, forming a large hump in the chromatogram referred to as Unresolved Complex Mixture (UCM). In this study, thermal desorption coupled to comprehensive Two Dimensional Gas-Chromatography Time-of-Flight Mass-Spectrometry (TD-GC × GC-ToF-MS) was exploited to characterise and quantify the composition of SVOCs from the exhaust emission. Samples were collected from the exhaust of a diesel engine, sampling before and after a diesel oxidation catalyst (DOC), while testing at steady state conditions. Engine exhaust was diluted with air and collected using both filter and impaction (nano-MOUDI), to resolve total mass and size resolved mass respectively. Adsorption tubes were utilised to collect SVOCs in the gas phase and they were then analysed using thermal desorption, while particle size distribution was evaluated by sampling with a DMS500. The SVOCs were observed to contain predominantlyn-alkanes, branched alkanes, alkyl-cycloalkanes, alkyl-benzenes, PAHs and various cyclic aromatics. Particle phase compounds identified were similar to those observed in engine lubricants, while vapour phase constituents were similar to those measured in fuels. Preliminary results are presented illustrating differences in the particle size distribution and SVOCs composition when collecting samples with and without a DOC. The results indicate that the DOC tested is of very limited efficiency, under the studied engine operating conditions, for removal of SVOCs, especially at the upper end of the molecular weight range.</p