But why work? The technology to distill ethanol is simple. Compare the capital and operation costs of bubble towers, catalytic crackers, etc. needed in petroleum refining to the cost of a cellulose----cellulase--->starch--->acid/diastase--->sugar---zymase---->EtOH process and you could throw more than half a petroleum plant's hardware away. You could do most of it in a bathtub.
I am not sure how vapor pressure enters into FI engines, where the fuel is atomized, but we already put low boilers like butane in Winter Blends. Ethyl Ether would work fine in an ethanol system.
In the so-called shortage of the early '70's, a few private pilots were using street gas. They would reach 5000 Feet, the butane would boil, they'd vapor lock and involuntarily decent/restart/repeat as needed. A good way of picking buttons off the seat.
Yikes!
Pure EtOH is NOT what comes out of a distillation process - at BEST you get an azeotropic mixture containing almost 5% water, too much to be used as fuel. It can be dehydrated by various processes, but is not ready to be used as fuel without further processing. ( http://www.chemguide.co.uk/physical/phaseeqia/nonideal.html )
The average yield of EtOH from cropland is about 8 barrels per acre per growing season, depending on irrigation - or the lack of it. This includes processing the entire plant, not just the grain. TWO THIRDS of our petroleum consumption goes to transportation fuel - gasoline, diesel, and jet fuel, and most of the rest goes to heavy oils, used for heating and ship fuel. 96% of our transportation fuel comes from petroleum. By my very rough calculation, planting every bit of both Texas and Tennessee with corn would get us up to 20% of our current petroleum consumption, or around 1/3 of our oil imports.
This monopoly exists because the very nature of transportation requires that the driving energy be carried within the vehicle, and with ambient oxygen available, nothing matches the energy density, convenience, and relative safety of a liquid hydrocarbon fuel like gasoline.
Your personal Diety designed the universe to have three efficient ways to store hydrogen: by gravity, in large bodies like stars and giant planets; combined with oxygen, as 11% of every water molecule; or as 14% to 18% of various hydrocarbon molecules when combined with three to a dozen or more carbon atoms. This truth leads me to believe that the transportation fuel of the future is very much like the transportation fuel of today, although it might be a fully synthesized product made from raw materials that do not include crude oil.
The very best custom-made hydrogen storage tanks used in these dead-end hydrogen powered "concept" cars can withstand about 10,000 PSI. The gas tank in the car in your driveway can hold nearly TWICE the amount of hydrogen per unit volume, WITHOUT pressurization - and the hydrogen can be separated from the carbon exothermically - without external energy, except to get the reaction started. Methods 1 and 2 are not applicable for on-board storage.
In addition, hydrogen distribution would require an incredibly complex new infrastructure. In fact, the only viable strategy is tank exchange, because anything else would consume large amounts of energy as the pressure changes across the system. Dispensing a gas is nothing at all like dispensing liquid, even under pressure.
Hybrid technology would be useful, but we need to go all the way, like the railroads have done. EVERY freight locomotive is diesel-electric - a diesel engine turning an electric generator that sends power to electric motors that turn the wheels. This is the only significant use of petroleum to generate electricty in this country. It works well because a diesel engine works best over only a narrow RPM range, perfect for an electric generator.
The real breakthrough technology would be to find a way to put most land transportation on the electric grid on major routes and within central cities. This would require some sort of trolley or slot system, and could not be done with what we have. But suppose we electrified the major rail routes, so that trains could run without diesel fuel. And then did the same for all the long-haul trucks, and for cars on intercity highways. How far would this have to go before the middle eastern countries would be exploring commercial use of sand, instead of exploiting consumers of their oil resources?