The underestimation of diesel exhaust hydrocarbons and its impact on the assessment of particulates
The underestimation of diesel exhaust hydrocarbons and its impact on the assessment of particulates
The underestimation of unburnt hydrocarbons (HC) in diesel engine exhaust is recognised in the analysis of engine exhaust emissions. The problem deserves greater attention because of the remarkable difference between diesel and petrol combustion systems. Attention has not been devoted to this area in recent years, apparently due to the lower level of diesel exhaust hydrocarbons. However, besides noise and oxides of nitrogen (NOx), diesel exhaust hydrocarbons present an unpleasant health-hazard dimension.
This work investigates these sources of errors in the measurement of total diesel exhaust HC and addresses the necessary requirements for their control and/or elimination. Recorded results reveal, from experiments using heated FIDs under different engine and equipment operating variables, a wide range of variations with slight changes in some measurement parameters. It shows that, due to the higher molecular weights of diesel HCs (mostly > 10 carbon atoms) and the excess-air factor of the diesel system, underestimation is much more than previously reported. Sources of error investigated include: sampling line, filters, FID oven temperature, probe location, oxidation catalysts and techniques. Unburnt hydrocarbon losses are quantified. For example, cold filtration, unheated sampling line, and temperature-dependent aftertreatment devices, may account for about 30-50% of exhaust hydrocarbons hung-up or trapped at cold start.
A spectrophotometric technique for the quantitation of filter-trapped, soluble HC extract is developed. It is applied to the analysis of losses due to filtration. The use of this method suggests an alternative technique for the assessment of soluble particulate organic matter.
University of Southampton
1992
Ene, Maurice O
(1992)
The underestimation of diesel exhaust hydrocarbons and its impact on the assessment of particulates.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The underestimation of unburnt hydrocarbons (HC) in diesel engine exhaust is recognised in the analysis of engine exhaust emissions. The problem deserves greater attention because of the remarkable difference between diesel and petrol combustion systems. Attention has not been devoted to this area in recent years, apparently due to the lower level of diesel exhaust hydrocarbons. However, besides noise and oxides of nitrogen (NOx), diesel exhaust hydrocarbons present an unpleasant health-hazard dimension.
This work investigates these sources of errors in the measurement of total diesel exhaust HC and addresses the necessary requirements for their control and/or elimination. Recorded results reveal, from experiments using heated FIDs under different engine and equipment operating variables, a wide range of variations with slight changes in some measurement parameters. It shows that, due to the higher molecular weights of diesel HCs (mostly > 10 carbon atoms) and the excess-air factor of the diesel system, underestimation is much more than previously reported. Sources of error investigated include: sampling line, filters, FID oven temperature, probe location, oxidation catalysts and techniques. Unburnt hydrocarbon losses are quantified. For example, cold filtration, unheated sampling line, and temperature-dependent aftertreatment devices, may account for about 30-50% of exhaust hydrocarbons hung-up or trapped at cold start.
A spectrophotometric technique for the quantitation of filter-trapped, soluble HC extract is developed. It is applied to the analysis of losses due to filtration. The use of this method suggests an alternative technique for the assessment of soluble particulate organic matter.
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Published date: 1992
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Local EPrints ID: 462204
URI: http://eprints.soton.ac.uk/id/eprint/462204
PURE UUID: af6a2770-73c8-4e85-b10c-4bda482748b4
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Date deposited: 04 Jul 2022 19:03
Last modified: 04 Jul 2022 19:03
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Author:
Maurice O Ene
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