Unregulated emissions have become an important factor
restricting the development of methanol and ethanol alternative
alcohols fuels. Using two light-duty vehicles fuelled with pure
gasoline, gasoline blend of 10% and 20% volume fraction of ethanol
fuels, gasoline blend of 15% and 30% volume fraction of methanol
fuels, New European Driving Cycle (NEDC) emission tests were
carried on a chassis dynamometer according to ECE R83-05. High
performance liquid chromatography (HPLC), Gas chromatography - Mass
spectrometry (GC-MS), Fourier transform infrared spectrometer
(FTIR) were used to measure methanol, formaldehyde, acetaldehyde,
acetone, benzene, toluene, xylene, ethylene, propylene,
1,3-butadiene and isobutene emissions in the exhaust during the
NEDC.
The test results show that the methods of the integration of
FTIR instantaneous values and the chemical analysis of bag sampling
can both accurately measure formaldehyde, acetaldehyde, and benzene
and toluene emissions in the vehicle exhaust. Comparing the
instantaneous emissions and average emissions during the driving
cycle of major pollutants, the good consistency of FTIR, HPLC and
GC-MS measuring methods has been verified. The emissions deviations
of various measurement methods are in the range of ± 10%.
During the first acceleration condition, the instantaneous
emissions of methanol, formaldehyde, acetaldehyde, benzene,
propylene and 1,3-butadiene have the highest peak. Then with the
three-way catalyst lights off, the emissions values gradually
reduce to nearly zero and remain until the end of the driving
cycle.
As the alcohols proportion increasing in the fuel, CO₂ emissions
in the exhaust remain basically the same, HC, CO and CH₄ emissions
decrease slightly, NOX emissions increases slightly, unburned
methanol, formaldehyde and acetaldehyde emissions increase
proportionally, benzene, toluene, ethylene, propylene,
1,3-butadiene and isobutene emissions decrease.
