Stephen Leonard Cook

Particulates Reduction in Diesel Engines Through the Combination of a Particulate Filter and Fuel Additive

Exhaust emissions legislation for diesel engines generally limits only the mass of emitted particulate matter. This limitation reflects the concerns and measurement technology at the time the legislation was drafted. However, evolving diesel particulate filter (DPF) systems offer the potential for reductions in the mass and more importantly, the number of particles emitted from diesel exhausts. Particulate filters require frequent cleaning or regeneration of accumulated soot, if the engine is to continue to operate satisfactorily. Exothermic reactions during regeneration can lead to severe thermal gradients in the filter system resulting in damage. Fuel additives have been evaluated to show significant reductions in light off temperature which allow frequent small regeneration events to occur, under mild operating conditions. The resulting small exotherms suggest that low back pressure filter systems giving frequent regenerations could in the future become as reliable in use as gasoline exhaust catalyst systems.

A study of the reactivity of (methyl 2-acetamidoacrylate)-tricarbonyliron(0) leading to a novel synthesis of β,β,β-trialkyl α-amino acids

Abstract (Methyl 2-acetamidoacrylate)tricarbonyliron(0) ( 3 ) reacts with 2 equivalents of methyllithium to give methyl N -acetylalaninate ( 4 ) and 2-acetamido-4-oxopentanoate ( 5 ) when the reaction is quenched with trifluoroacetic acid. Production of methyl N -acetylalaninate is dependent only on the presence of trifluoroacetic acid, and the ratio of 4 to 5 generated in these reactions is related to the quantity of trifluoroacetic acid used to quench them. Addition of two equivalents of methyllithium followed by tertiary haloalkanes gives protected β,β,β-trialkyl α-amino acids which may be hydrolysed to give tert-leucine ( 13 ) and the new α-amino acids 2-amino-3,3-dimethylpentanoic acid ( 14 ) and 2-amino-3,3-dimethylhexanoic acid ( 15 ).

Surprising reactivity of (methyl 2-acetamidoacrylate)tricarbonyliron(0) leading to the synthesis of β,β,β,-trialkyl α-amino acids

Addition of methyllithium followed by tertiary haloalkanes to readily available and air-stable (methyl 2-acetamidoacrylate)tricarbonyliron(0)1, gives protected β,β,β-trialkyl α-amino acids which are hydrolysed to give tert-leucine 10 and the new α-amino acids 2-amino-3,3-dimethylpentanoic acid 11 and 2-amino-3,3-dimethylhexanoic acid 12.

Addressing the Issue of Fuel Filter Fouling with Recent Changes in Fuel Quality

The recent introduction of biodiesel blends to the U.S. market has coincided with an increase in the reported problems of fouling of fuel filters and fuel injection equipment, manifested in power loss, noise, vibration, and increased filter changes. However, the introduction of biodiesel has to a large extent coincided with the introduction of ultra low sulfur diesel fuel and changes in engine technology, leading to higher fuel injection pressures. It is thus proposed that current incidences of fouling are not a problem brought about solely as a result of the introduction of biodiesel. A review of known fuel degradation mechanisms suggests that the effects of increased fuel pressure and also high shear environments should be examined as a probable cause of increasing deposit formation. Deposit formation on both fuel filters and injectors has previously been attributed to a variety of sources including: Biological contamination, both aerobic and non-aerobic, water contamination, adulteration with lubricating oil, fuel additive interactions, and biodiesel degradation. The deposits currently being encountered appear to be more akin to the high carbon content particles found in diesel exhaust than those previously described and are frequently found in the presence of deposit precursor molecules. This paper concentrates on the issue of fuel filter fouling, presents the analysis of currently encountered deposits, relates these results to some of the degradation mechanisms alluded to above, and suggests possible precursor molecules in fuels both pre and post stressing to support the proposed mechanisms. It is also shown that existing fuel quality tests do not correlate well with reported fouling propensity, suggesting that new test methods are required to ensure future fuels are fit for purpose.