GEM Ternary Blends: Testing Iso-Stoichiometric Mixtures of Gasoline, Ethanol and Methanol in a Production Flex-Fuel Vehicle Fitted with a Physical Alcohol Sensor 2012-01-1279
The paper presents vehicle-based test work using tri-component,
or ternary, blends of gasoline, ethanol and methanol for which the
stoichiometric air-fuel ratio (AFR) was controlled to be 9.7:1.
This is the same as that of conventional "E85"
alcohol-based fuel. Such ternary blends are termed "GEM"
after the first initial of the three components. The present work
was a continuation of an earlier successful project which
established that the blends were effectively invisible to a car
using a virtual alcohol sensor. The vehicle used here employed the
other major technology in flex-fuel vehicles to determine the
proportion of alcohol fuel in the tank, a physical alcohol
Another aspect of the present work included the desire to
investigate ternary blend replacements for E85 having low ethanol
concentrations. Evidence from the previous work suggested that
under specific conditions, ethanol was required in some amount to
act as a cosolvent for the gasoline and methanol in the blend. The
present paper discusses the position of the phase separation
boundary with respect to the concentration of the individual
components, and determines new blends for test which are closer to
this boundary. These and other ternary blends were first tested on
the road and in a cold chamber, where cold startability was gauged
at -20°C. All of the ternary blends were found to start well except
that corresponding to E85, which would not start at all at this low
temperature using this summer grade fuel.
Of the fuel blends tested in the first phase, four were selected
for more-controlled investigation in an emissions laboratory. Each
was tested twice on the NEDC cycle under cold and hot conditions.
In addition, gasoline baseline tests (using the same procedure)
were conducted at the start and end of the ternary blend tests. The
ternary blends were invisible to the vehicle, with no malfunction
indicator light activity at all.
An estimate of the cost of one of the blends (containing 10% by
volume ethanol), based on current individual costs of the
individual components, is made to be 10.1% cheaper than gasoline,
on an energy basis. Finally, there is a discussion of how renewable
methanol can be introduced, aided by the ability of the existing
flex-fuel vehicle fleet to accept these fuel blends, and also of a
means of manufacturing such fully sustainable methanol by a
coupling of the electricity and gas grids to enable massive storage
of renewable energy.
Citation: Turner, J., Pearson, R., McGregor, M., Ramsay, J. et al., "GEM Ternary Blends: Testing Iso-Stoichiometric Mixtures of Gasoline, Ethanol and Methanol in a Production Flex-Fuel Vehicle Fitted with a Physical Alcohol Sensor," SAE Technical Paper 2012-01-1279, 2012, https://doi.org/10.4271/2012-01-1279. Download Citation
James W G Turner, Richard J Pearson, Mark A McGregor, John M Ramsay, Eelco Dekker, Ben Iosefa, Gregory A Dolan, Kenth Johansson, Kjell ac Bergström
Lotus Engineering, BioMCN, Methanex Corporation, Methanol Institute, Saab Automobile Powertrain AB