This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Iso-Stoichiometric Ternary Blends of Gasoline, Ethanol and Methanol: Investigations into Exhaust Emissions, Blend Properties and Octane Numbers
Journal Article
2012-01-1586
ISSN: 1946-3952, e-ISSN: 1946-3960
Sector:
Topic:
Citation:
Turner, J., Pearson, R., Bell, A., de Goede, S. et al., "Iso-Stoichiometric Ternary Blends of Gasoline, Ethanol and Methanol: Investigations into Exhaust Emissions, Blend Properties and Octane Numbers," SAE Int. J. Fuels Lubr. 5(3):945-967, 2012, https://doi.org/10.4271/2012-01-1586.
Language:
English
Abstract:
Iso-stoichiometric ternary blends - in which three-component
blends of gasoline, ethanol and methanol are configured to the same
stoichiometric air-fuel ratio as an equivalent binary
ethanol-gasoline blend - can function as invisible
"drop-in" fuels suitable for the existing E85/gasoline
flex-fuel vehicle fleet. This has been demonstrated for the two
principal means of detecting alcohol content in such vehicles,
which are considered to be a virtual, or software-based, sensor,
and a physical sensor in the fuel line. Furthermore when using such
fuels the tailpipe CO₂ emissions are essentially identical to those
found when the vehicle is operated on E85. Because of the fact that
methanol can be made from a wider range of feed stocks than ethanol
and at a cheaper price, these blends then provide opportunities to
improve energy security, to reduce greenhouse gas emissions and to
produce a fuel blend which could potentially be cheaper on a
cost-per-unit-energy basis than gasoline or diesel.
The present work extends the validation process for these blends
by presenting exhaust emissions measured from a vehicle fitted with
a physical alcohol sensor and operated on several ternary blends
equivalent to E85. These results show that existing emissions
control technology can easily manage exhaust gas aftertreatment
when a vehicle is operated on such blends. This is an important
finding with regard to their manufacturer and regulatory
acceptance.
Also, the impact of the methanol-containing nature of ternary
blends was investigated. In order to do this, target ternary blends
of gasoline, ethanol and methanol were prepared with the low oxygen
content Coordinated European Council (CEC) emissions reference fuel
CEC RF-02-03 and results of physicochemical analyses are presented.
These include water tolerance, blend stability, thermal and
oxidative stability, volatility and density. Nitrile rubber, Viton
and silicone rubber seal swell properties are presented and
discussed. In order to investigate octane effects,
iso-stoichiometric blends equivalent to E15 were prepared and
analyzed, and utilizing molar octane blending modeling the expected
E85-equivalent blend octane indices can be predicted.
As a result of this work observations are made on air-quality
and materials compatibility impacts, and the attractiveness of the
approach from a governmental and customer viewpoint.