Alcohol as a fuel

On Tue, 10 May 2005, C. E. White wrote:

> Chevron was saying that must cars will run fine on oxygenated fuel. I am
> not sure what you mean when you say you get less power. If you mean you
> lose engine power, I don't agree. I believe the fuel injection systems
> of most modern vehicles have enough fuel delivery capacity to increase
> fuel delivery to make up for the reduced energy content of the
> oxygenated fuel.

Doesn't work that way unless you have forced induction (supercharger or
turbocharger). Yours is a common error, though, thinking that a correction
in air/fuel ratio will make up for the reduced energy content of the fuel.
Air is the working fluid -- fuel's just used to heat up the air so it
expands and does work. Less energy in the fuel = less heat = less bang =
less power. One does not trump this physical law by monkeying with the
air/fuel ratio.

DS

On Tue, 10 May 2005, dyno wrote:

> Since both ethanol and methanol have less energy per volume of fuel, one
> just adds more fuel until all of the oxygen is consumed.

<snip a bunch of inapplicable handwaving and ooh-ha-ha>

....and we still wind up with less work done by a given volume of fuel.
Call it lower MPGs or lower power, whichever you like, it doesn't really
matter. For any set of conditions, one gallon of gasoline does more work
than one gallon of ethanol or methanol, straight or blended with gasoline,
simply because the alcohols contain less energy. And that's just always
the case. Ethanol and methanol both contain less energy than gasoline, per
volume unit, period, no matter what magic modifications you do to an
engine.

To the degree the effective air-fuel ratio is leaned by the use of alcohol
relative to gasoline, the mixture can be corrected by dumping in more
fuel, but this doesn't mean you get the lost power back. Putting the
effect into real-world terms, as long as you have travel left in the
accelerator, you can simply push it down further with alcohol-blended fuel
than with gasoline to compensate for the loss, though MPGs will continue
to suffer. However, this is just *compensation*, not deletion of the loss.
The extreme case illustrates this: In the extreme case (Underpowered,
fully-loaded vehicle climbing a mountain highway, let's say) when the
accelerator is already on the floorboard and you're climbing the hill at
35 mph in the right lane with your blinkers going -- running on gasoline
-- changing to a lower-energy-content fuel means your foot will still be
on the floor but you'll be doing, say, 25 or 30 mph instead of 35. (I
didn't run the calculations to come up with an exact mph difference; the
point is illustrative without it.)

DS

Daniel J. Stern wrote:
> On Tue, 10 May 2005, C. E. White wrote:
>
>
>>Chevron was saying that must cars will run fine on oxygenated fuel. I am
>>not sure what you mean when you say you get less power. If you mean you
>>lose engine power, I don't agree. I believe the fuel injection systems
>>of most modern vehicles have enough fuel delivery capacity to increase
>>fuel delivery to make up for the reduced energy content of the
>>oxygenated fuel.
>
>
> Doesn't work that way unless you have forced induction (supercharger or
> turbocharger). Yours is a common error, though, thinking that a correction
> in air/fuel ratio will make up for the reduced energy content of the fuel.
> Air is the working fluid -- fuel's just used to heat up the air so it
> expands and does work. Less energy in the fuel = less heat = less bang =
> less power. One does not trump this physical law by monkeying with the
> air/fuel ratio.
>
> DS


The PROPER fuel air mixture will return the power, as the proper mixture
for alcohol is twice the fuel per unit of air than gasoline. IF the
engine is made to sense alcohol, as in an E85 vehicle, it will restore
the power, though not the milage. I doubt if non-E85 setups will
recalibrate, however.

My vintage racing car is set up to run alky. The main jets are bored
out to approx twice the area of the stock jets. Car runs great- lots of
power. I am running the stock CR, and whenever I have to rebuild
engine, I will raise CR so that I will get even more power than
currently. Alky powered cars are not wimpy. They sure guzzle fuel,
however. Even though alky is cheaper here than gasoline, it still costs
me more than if I were using gasoline.

Don Stauffer wrote:
>
> My vintage racing car is set up to run alky. The main jets are bored
> out to approx twice the area of the stock jets. Car runs great- lots of
> power. I am running the stock CR, and whenever I have to rebuild
> engine, I will raise CR so that I will get even more power than
> currently. Alky powered cars are not wimpy. They sure guzzle fuel,
> however. Even though alky is cheaper here than gasoline, it still costs
> me more than if I were using gasoline.

Was talking to a local sprint car guy that runs alky...
in a 25 lap race on a 4/10 mile track, they'll use almost 30 gallons.
Yikes.