Better Use For Cellulosic Ethanol

Prospects for “cellulosic” ethanol, as well as for corn-based ethanol, could be significantly enhanced if its superior fuel properties were employed to increase efficiency of gasoline use (C&EN, Sept. 13, page 20).

This can be accomplished by on-demand direct injection of ethanol to remove the knock limit on compression ratio and turbocharging in gasoline engines. Evaporative cooling from directly injected ethanol provides knock suppression equivalent to 130-octane fuel. In this way, a small amount of ethanol provided by a separate tank can be used to enable diesel-like high efficiency with advantages of substantially lower cost, higher power, and lower emissions than diesel engines. Greater amounts of ethanol can be used if desired by flexible fuel operation with ethanol-gasoline mixtures in the main fuel tank.

The “ethanol boosted” gasoline concept was originated at Massachusetts Institute of Technology. It is now being developed by a spin-off company, Ethanol Boosting Systems (EBS). Engine tests at Ford Motor Co. have confirmed the basic advantages of the concept. Ethanol boosting significantly increases the value of ethanol in light-duty vehicles by using it in a leveraged way to increase efficiency of gasoline engines and by providing higher performance and efficiency from flexible fuel engines. It also facilitates ethanol use with gasoline in heavy-duty vehicles.

In my opinion, the most exciting aspect of alcohol boosting is that for the first time a biofuel can be profitably used on a large scale at present-day fuel prices! This opens up the prospect of a less impoverished postpetroleum lifestyle for all of us.

John M. Bradley
Manchester-by-the-Sea, Mass.