This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Measurement Methodologies for Hydrocarbons, Ethanol and Aldehyde Emissions from Ethanol Fuelled Vehicles
Abstract:
Alternative-fuelled vehicles are a growing market, and emission
performance of these vehicles should be thoroughly investigated.
The emission legislation is however very diversified in different
countries; a short summary of the legislation in the EU, the USA
and Brazil is presented in this study. In the EU regulations,
everything measured with the FID (Flame Ionization Detector) is
treated as hydrocarbon emissions. In the USA the alcohols and
aldehydes are measured and reported separately from hydrocarbons.
In Brazil, the alcohol part can be measured separately on voluntary
basis. The influence of some of these differences has been further
investigated in this report.
Results from two related studies are presented. The FID response
for ethanol was investigated and emission testing of an E85-fuelled
FFV (Flex Fuel Vehicle) was performed.
The FID sensitivity at two different detector temperatures -
113°C (as stated by the US EPA when testing alcohol-fuelled
vehicles) and 190°C (often used as default setting in the EU) -
were investigated showing a higher FID response at 113°C. The
response curve shows a slow response due to adsorption of ethanol
in the measurement system.
One FFV fuelled with E85 was tested on chassis dynamometer at
two ambient temperatures: +22°C and -7°C. The ethanol emissions
were analyzed with FTIR and sampled in impingers (standardized
method approved in the USA). The acetaldehyde emissions were
analyzed with FTIR and sampled in DNPH(2,4-dinitrophenyl
hydrazine)-cartridges (standardized method approved in the USA).
The FTIR provides second-by-second data which showed that high
levels of unburned ethanol were emitted during the cold start
phase. Comparison between the FTIR results and methods standardized
in the USA were performed.
The percentage distribution of some of the components included
in the total hydrocarbons measured by the FID was investigated, and
comparison between tests performed at the two different ambient
temperatures can be made. The proportion of unburned ethanol
increased at cold climate testing - from 24% at +22°C up to 53% at
-7°C.