<VV> E85 fuel (NO CORVAIR)

[Rad Davis]

As an ex-emissions chemist, I guess I should take this one.

Theoretically, there's no difference at all between the combustion products 
of a hydrocarbon and an alcohol - you get water (steam) and CO2.  Of 
course, we wouldn't have the word "practice" if theory and practice were 
identical.  The difference in this case is that we don't get complete 
combustion in the real world.  It's the products of incomplete combustion 
that cause some types of smog, carbon monoxide poisoning, etc.

In practice, the combustion products of alcohols are environmentally a 
little more benign than those of hydrocarbons (gasoline, propane), but tend 
to pose bigger health problems for mammals like us.

If you postulate a cold engine and a rich mixture, as with a cold start 
with the choke on, gasoline gives you unburned hydrocarbons and CO (carbon 
monoxide) along with your steam and CO2.  The unburned (and 
partially-burned) HCs are responsible for some types of smog, but tend not 
to have dramatic health consequences (assuming it's a low-aromatic content 
gasoline, which is mostly true now).  CO is bad, of course, but mostly if 
you're in a confined space with it.  It's pretty reactive and tends to "go 
away" quickly in atmosphere.   Note that I don't mean to imply that 
breathing the exhaust of a cold gasoline-burning engine is good for you, 
just that it consists of something immediately poisonous (CO) that 
dissipates quickly, and something that may cause cancer in lab rats (HC) 
but tends to pose more of an epidemiological threat than an immediate 
health risk.

Start the same cold engine running E85 or M85, but be careful to stand 
upwind!  Yes, you get some alcohol vapor as your unburned fuel component, 
just like the gasoline vapor in the example above.   You also get some 
CO,  because the engine's running rich, and you're getting incomplete 
combustion.  Now for the bad news:  you also get a flavorful assortment of 
short-chain aldehydes.  Ethanol vapor is not particularly bad for you, but 
formaldehyde and acetaldehyde are.  It's not an accident that formaldehyde 
is used to preserve animal tissue - just about nothing can live around the 
stuff.  It's a well-documented carcinogen on the level of benzene, which 
has been (mostly) removed from gasolines because of its carcinogenic nature.

Once the engine gets hot, of course, the evil stuff mostly goes away, 
particular if you're running stoichiometric or lean mixtures and a 
catalytic converter.  For something like a mostly-stock Corvair, however, 
the emissions are not all that nice to be around.

The ethanol lobby has been careful to hand-wave this away, citing 
electronic fuel injection and catalytic converters as fixing most of the 
problem.  They're right - they do fix most of it.  Of course, the emissions 
and environmental benefits of ethanol are calculated assuming that we all 
drive carbureted cars from 1979, but nobody seems to notice that--too much 
money flying around for common sense and good science to get in the way of 
politics.

If I were going to put my corvairs on a gasoline-free diet, I would convert 
to propane.  The energy density is about the same as that of Ethanol.  It's 
not particularly corrosive, and it has a good octane number and 
readily-available hardware.  Of course, Joe Corncob probably isn't 
benefiting from my choice, and the federal government isn't subsidizing it 
like they are ethanol.  If I had to go to ethanol, I'd put on an EFI 
system.  You have to replumb the whole thing to deal with the corrosiveness 
of the fuel anyway, so you may as well update to a better control system 
while you're at it.

- Rad Davis



At 02:43 PM 2/24/2006 -0800, Chris C, Warwick RI wrote:
>Stupid question.  How would the emissions of an E-85 burner differ from 
>regular gas.  Say I setup the 65 to run on it.
>
>At 10:27 AM 2/24/2006, you wrote:
>>     While I see some value in considering NET energy, isn't the SELLING 
>> PRICE
>>per unit of energy what really matters?  If the oil producing countries
>>decide to raise the price per barrel from the current $60 to say $100 the NET
>>energy won't change at all.  After all,  they raised the price 35 years 
>>ago from $3
>>to $30.
>>     I see a similar thing happening with the current prices for natural gas
>>and electricity.  For many years, the price I paid for natural gas was about
>>1/4 of the price for electricity based on energy content.  Recently, however,
>>the natural gas price is nearly HALF of the electric price.  Taking into 
>>account
>>the relative efficiencies (my old gas-fired furnace is probably sending 40%
>>of the natural gas energy up the chimney while electric heat is 100% 
>>efficient
>>since NO energy goes up the chimney) it's nearly getting to the point where
>>electric heat is approaching natural gas heat on a PRICE basis.
>>     Since E-85 has about 70% of the energy value of gasoline (on a gallon
>>basis), E-85 at $2 per gallon is equivalent to $2/70% = $2.86 for a gallon of
>>gasoline.  This is assuming the same engine burns either fuel.  If the 
>>engine is
>>modified (higher CR or higher boost or more timing, et al.) to benefit from
>>the higher octane of E-85, it will do a more efficient job of utilizing 
>>E-85's
>>lesser energy content to narrow the mpg difference between the 2 fuels.  In
>>addition, the much greater cooling effect of evaporating E-85 in the 
>>intake tract
>>would serve to produce an intercooling effect on a boosted engine.  Sort of
>>like water-alcohol injection but without the water.<GGGG>
>>     The governor of NY State (George Pataki) has recently announced a 
>> program
>>to put alternative energy fuels like E-85 at service stations along the NY
>>State Thruway.  In addition, plans are underway to construct a ethanol fuel
>>plant in southern NJ, so maybe we will finally begin to see some E-85 for 
>>sale in
>>the Northeast.
>>     Frank "prefers to give my $ to Joe Corncob than to Osama Muhammed"
>>Burkhard
>>
>>Rad Davis:                                        rad.davis at comcast.net
>
>Corvairs--65, 66 Corsa coupes, '65 'brier Deluxe   http://www.corvair.org/
>Keeper of the Forward Control Corvair Primer: 
>http://www.mindspring.com/~corvair/fc1.html
>"We did Nebraska in seven minutes today. I think that's probably the best 
>way to do Nebraska."                            --Brian Shul, _Sled Driver_