Posted on 05/17/2002 7:30:52 AM PDT by Willie Green
Edited on 04/13/2004 1:39:35 AM PDT by Jim Robinson. [history]
Ethanol makes up just 1.2% of the nation's gasoline supply, and its production employs just 0.1% of the nation's workforce. But in Washington, the renewable fuel is increasingly sold on both sides of the political aisle as a magic elixir for the nation's energy, economic and environmental woes. And the unbridled enthusiasm could cost consumers at the gas pumps for a product that hasn't proved it can live up to supporters' claims.
(Excerpt) Read more at usatoday.com ...
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High-speed rail as an alternative mode of transportation in the U.S. is long overdue. We are reaching the point of diminishing returns as we expand our 4-lane interstates to 6 or (gasp!!!) 8 lanes. And even costly airport expansions make little sense when (prior to 9/11) the air corridors themselves are over-congested.
High-speed rail and maglev offer the perfect alternative to augment & supplement our highway and air transportation infrastructure. For regional trips between 150 and 350 miles, it is faster than automobile and not that much slower than air. Yet offers the potential to alleviate both congested highways and air corridors!
In light of current economic conditions, construction of this vital transportation infrastructure should be accelerated.
BTW, ethanol can be made directly from a petroleum derivative, ethane, by combining it with water vapor and cutting an OH radical in with the ethane molecule by use of a catalyst. Ethanol, or ethyl alcohol, and free hydrogen result from this reaction.
Not to mention petroleum-based fertilizers and pesticides.
Not a very energy-efficient conversion process.
Besides, I can think of a better use for corn liquor than burning in an engine.
Steam engines have the potential to be quite efficient, though getting such efficiencies typically requires large heat exchanges and condensers. Interestingly, the first steam engines operated entirely below atmospheric pressure; soon after that came engines which would have low pressure steam (a few PSI) on one side of the piston and partial vacuum on the other. It's interesting that I'm not aware of any widely-used locomotives that used condensers since while doing so prevents use of the steam for drafting the fire, it allows the extraction of more energy from the steam than venting to atmosphere. It also reduces the need to constantly add water.
My personal idea for an improved engine concept would be an engine in which the combustion takes place between input pumps and output pistons. Adding a catalytic convertor here would result in the convertor's heat being turned into useful energy (instead of just waste heat, as on a conventional car engine). Using a two-stage pump before combustion, and two-stage pistons after combustion, with a heat exchanger to transfer heat from the area between the latter two stages to the area between the former two stages should allow for very effective heat utilization, especially when used with a short-chain hydrocarbon such as methane (condensation between the latter two stages would not only be useful for preheating the fuel between the former stages, but would also improve mechanical efficiency by reducing the volume of fluid to be pumped out at atmospheric pressure).
To be particularly efficient, this design would probably require the pumps to be rigged for variable-displacement operation. Such operation should be feasible, however.
BTW, I've read that some work is being done with variable-displacement internal combustion engines. If this pans out, this could yield substantial improvements in efficiency since currently the only way to limit the power output of a large-displacement engine is to either throttle it or use gearing to increase torque and thus decrease RPM; both of these options reduce efficiency. Having an engine run at reduced displacement except when peak power is demanded would avoid these efficiency losses.
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