The influence of various oxygenated functional groups in carbonyl and ether compounds on compression ignition and exhaust gas emissions

An overview of the effects of fuel molecular structure on the combustion and emissions characteristics of compression ignition engines

“…52 In Figure 5(a), it can be seen that adding an oxygen atom to 5-nonanone to form butyl valerate increases the duration of ignition delay, as does the addition of a further oxygen atom to form di-nbutyl carbonate. Conversely, it can be seen in Figure 5(b) that the addition of oxygen atoms within the alkyl chain as ether linkages results in a decrease in ignition delay.…”

“…43,53 However, the presence of oxygen atoms within the alkyl chains of ethers increases the rate of hydrogen abstraction (by reduction in the adjacent C-H bond strength), the rates of isomerisation and also subsequent radical propagation. 52,[54][55][56] By studying various terpenes potentially produced by genetically modified cyanobacteria, Hellier et al 57 observed that, of the molecules tested which represented a change to only the functional group of geraniol (a C 10 alcohol), the equivalent aldehyde, geranial, exhibited the largest decrease in the duration of ignition delay. This is consistent with cetane number measurements of aldehydes relative to equivalent alcohols (octanal and octanol 32 ); aldehydes are known to be intermediates in the low-temperature reactions of alcohols, 58 the higher reactivity of which can be attributed to the relative ease with which peroxy radicals may be formed, requiring the abstraction of a single hydrogen atom without the addition of oxygen.…”

“…Whereas the reduction in the exhaust emissions of PM are mainly correlated with the fraction of oxygen in the fuel, there are known to be differences in the relative effectiveness of different oxygenated molecules in reducing the diesel engine emissions of PM, which have been demonstrated by a number of experimental studies 52,104,[106][107][108][109] and predicted by numerical kinetic modelling. 110 Isotope-labelling experiments have been carried out to aid the understanding of how oxygen influences the conversion of carbon to PM.…”

Transesterification of high-acidity spent coffee ground oil and subsequent combustion and emissions characteristics in a compression-ignition engine

“…All the experiments were conducted with the test fuels maintained at ambient conditions (∼30°C), except for the raw coffee oil which was heated to 45°C to avoid solidification. Previous studies have reported that a rise in temperature up to 38°C caused only a small decrease in the ignition delay that was of low significance [35,36].…”

Effects of oxygen-containing functional groups on the synergy effect in pulsed bipolar plasma-catalytic reactions of volatile organic compounds

“…Small-chain oxygenated compounds such as alcohols, esters, and carbonyls compounds are widely used as solvents, raw materials, or fuel additives. [1][2][3] In addition, they are the main components in vehicle exhaust. 4,5 Therefore, they are oen present in high concentrations in the exhaust gases resulting from industrial processes and mobile sources and require treatment.…”