Influence of Combustion Characteristics and Fuel Composition on Exhaust PAHs in a Compression Ignition Engine

Abstract

This paper reports an experimental investigation into the effects of fuel composition on the exhaust emission of toxic polycyclic aromatic hydrocarbons (PAHs) from a diesel engine, operated at both constant fuel injection and constant fuel ignition modes. The paper quantifies the US EPA (United State Environmental Protection Agency) 16 priority PAHs produced from combustion of fossil diesel fuel and several model fuel blends of n-heptane, toluene and methyl decanoate in a single-cylinder diesel research engine based on a commercial light duty automotive engine. It was found that the level of total PAHs emitted by the various fuel blends decreased with increasing fuel ignition delay and premixed burn fraction, however, where the ignition delay of a fuel blend was decreased with use of an ignition improving additive the level of particulate phase PAH also decreased. Increasing the level of toluene present in the fuel blends decreased levels of low toxicity of two to four ring PAH, while displacing n-heptane with methyl decanoate increased particulate phase adsorbed PAH. Overall, the composition of the fuels investigated was found to have more influence on the concentration of exhaust PAHs formed than that of combustion characteristics, including ignition delay, peak heat release rate and the extent of the premixed burn fractions.

Effect of equalising ignition delay on combustion and soot emission characteristics of model fuel blends

“…The sampling probe was thermally insulated to avoid condensation of water vapor. Detail description of generating and sampling particulates can be found in Dandajeh et al [9], [29] Soot particles were sampled on a glass micro fibre filter, its mass (Ms) and the total volume of gas (Vg) that passed through the filter were recorded. The sampling durations for the soot particles generated from the combustion of the model fuels was 15 min at all conditions tested.…”

“…To control and reduce particulate emissions and their associated toxicities, there has been substantial body of research in the literature 2 that employed several strategies. Such strategies have evolved from combusting fuels at low temperatures [7] or using diesel particulate filters [8] and to the reduction of toxic particulate precursors [9].…”

The Potential of Oxygenates to Increase the Risk of Exposure to Polycyclic Aromatic Hydrocarbons through Groundwater Contamination

“…The innovation of adding ethanol to gasoline aimed at reducing the emission of CO 2 and particulate matter [6][7][8], but it is not without attendant consequences. One major implication is the effect of co-solvency on the leaching potentials [9] and biodegradation [10] of petroleum hydrocarbons, with most concern being focused on monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX).…”

Influence of unsaturation of hydrocarbons on the characteristics and carcinogenicity of soot particles

“…Large atmospheric soot particles of diameter lower than 10 μm emitted from various combustion sources could be accumulated into the superior airways of respiration [ 4 , 5 ]. Inhalable soot particles of diameter lower than 1 μm and ultrafine particles of diameter less than 100 nm, carrying toxic PAHs, are possibly deposited into the lung of a human being, leading to health complications such as lung cancer, cardiovascular diseases and ultimately premature death [ 6 ].…”