Fuel Economy Study (Ethanol blends versus std. gasoline)

January 04, 2009, 02:29:34 PM

From Fuel Economy Study - Comparing Performance and Cost of Various Ethanol Blends and Standard Unleaded Gasoline:

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RESULTS
1) The three vehicles averaged
1.5% lower mileage with E10,
2.2% lower mileage with E20,
5.1% lower mileage with E30,
and miles per gallon actually increased by an average of 1.7% when using E10AK made with the specially denatured ethanol. E10AK was the highest mileage fuel in two of three cars.
...

I thought this was an interesting study - go read it to see the detail of the experiment. It seems to show that there is not direct correlation between the BTU content of alcohol blended fuels and gas mileage.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #1 – January 04, 2009, 02:53:37 PM

it says in my owners manual for my flex-fuel 2000 grand caravan that when you use e85 you should notice a 5% drop in fuel mileage and 10% drop in power..... the justification for this is that even thought you actually spend more per gallon for the e85, the exhaust is much cleaner and you're not burning nearly as much fossil fuel product...... for me, if i'm not saving money, i'm not going to do it

in an unrelated "did you know", i was watching modern marvels the other night and they said that 15% of the US rice crop is bought by Anheuser-Busch for the production of beer....... no wonder my minute rice is so expensive :)

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #2 – January 04, 2009, 03:12:36 PM

Quote from: mywifeskitty;250172

for me, if i'm not saving money, i'm not going to do it

The American motto... ;)

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #3 – January 04, 2009, 03:14:46 PM

Quote from: Cougar5.0;250175

The American motto...

so is running a catless h-pipe

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #4 – January 04, 2009, 06:03:43 PM

Quote from: Cougar5.0;250175

The American motto...

Maybe so, but how many of us should be wasting money in these economically tough times? I'm sure there's a few people here who've been laid off as of late. If it's a choice between feeling better about clean exhaust and paying the electric bill guess which one gets my vote?

Even though the prices of crude have come crashing back down I still find myself operating as if it were $4.50 for a gallon of regular. The Mustang and Cougar have seen a LOT less road time than at this time last year.

Until the people who make/advertise/distribute the product realize this they are doomed to not have the breakthrough in sales they so desparately want.

The American motto?
Basic survival for some.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #5 – January 04, 2009, 06:46:01 PM

It's been over 30 years since the original gas crunch. There have been several economic booms and busts in that time, so it's never been about good times versus bad. I was more or less commenting about long term planning versus short term - not simple day to day pocket book issues.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #6 – January 04, 2009, 07:14:45 PM

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There have been several economic booms and busts in that time, so it's never been about good times versus bad

This is true, but even in good times some people don't have it so good.

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I was more or less commenting about long term planning versus short term - not simple day to day pocket book issues.

You mean on an individual level or society as a whole? You've lost me....

I still say it has to be cost effective for the public as a whole to embrace it

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #7 – January 04, 2009, 07:28:26 PM

I actually posted this because I thought it was interesting that E10 may not reduce mileage as much as people claim.

Ethanol has no future anyway and doesn't necessarily reduce pollution, so I'm not sure where everyone is coming from.

Of course the long-term versus short-term is related to the long-term stability of our nation though. Clearly we could make cost efficient alternate fuels if we as a nation really wanted to.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #8 – January 04, 2009, 10:48:16 PM

I want them to actually start looking into hydrogen and actually giving discounts for using propane. Either one is better off, cheaper, and easier to produce/distribute.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #9 – January 05, 2009, 01:49:29 PM

Quote from: Cougar5.0;250203

I actually posted this because I thought it was interesting that E10 may not reduce mileage as much as people claim.

Interesting study. First one I've to actually try and measure mpg differences.

There are a few things I didn't like about the testing methodology though.

First, funding was from a biased source, The American Coalition for Ethanol.

Second, their fueling method. They drained the tank with the in-tank pump. Then put in 5 gallons of the test fuel. I don't know about modern vehicles, but I know my Cougar/Tbird leave a decent bit of fuel (~1 gal?) of gas in the tank after the pump quits pulling gas. If you pump out gas (leaving 1 gal in), then add in 5 gal of E10, you actually have E5.

Third, testing wasn't blind or double blind. Too easy to manipulate results by changing throttle inputs/etc when one knows what is in the tank. The plus side is their route was flat and on the interstate, so if they just set the cruise you eliminate purposeful or subconscious variations.

Fourth, need more data. Each fuel was run 3 times on a ~100 mile test loop. They only released the aggregate data set. Seeing the separate runs could allow one to flesh out the severity of the fueling flaw (or if it's a problem at all) and total variability.

One odd thing I noticed was the difference in miles traveled for each testing sequence. Gasoline has the worst variation, between 317.0 and 339.7 miles. How do you travel 22.7 miles extra when you have a standardized 100 miles testing loop?

Given the unexpected outcome, I'd hope someone would go a step further and perform controlled dyno tests using standardized EPA tests and/or real world driving conditions.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #10 – January 05, 2009, 02:42:19 PM

You'd think an engineering college somewhere could do a study in even more controlled conditions, though you have to admit that compared to "internet claims", they've done one heck of a lot better job of experimental control. Here is a quote from Wiki that references EPA.gov in the footnotes:

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For E10 (10% ethanol and 90% gasoline), the effect (fuel economy) is small (~3%) when compared to conventional gasoline, and even smaller (1-2%) when compared to oxygenated and reformulated blends.

1-2% compared to "oxygenated & reformulated blends" seems to fall in line with the study above. Since the energy content is only about 3.4% lower in E10, people claiming 10% or more reduction in fuel mileage with E10 really should be asked about their "methods".

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Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles resulted 25.56% lower than unleaded gasoline.

Since E85 has about 29% less energy content, there seems to be an efficiency gain in blends that could peak at some blend between 10 & 85% which might explain the 5% lower fuel mileage of E30 versus the approx. 10% expected loss.

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #11 – January 05, 2009, 03:21:17 PM

Quote from: Cougar 5.0

1-2% compared to "oxygenated & reformulated blends" seems to fall in line with the study above. Since the energy content is only about 3.4% lower in E10, people claiming 10% or more reduction in fuel mileage with E10 really should be asked about their "methods".

I would expect mpg for Ethanol blends to slightly exceed what is predicted due to decreased pumping losses.

So is it possible the 100% gasoline was a oxygenated/reformulated blend and the E10/20/30 was mixed with nonoxygenated/nonreforumlated gas?
Do they make E10 with a oxygenated/reformulated base?

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #12 – January 05, 2009, 05:01:41 PM

Hey man, time to do some research of your own!

I'm just a grunt! :hick:

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #13 – January 05, 2009, 05:34:20 PM

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I would expect mpg for Ethanol blends to slightly exceed what is predicted due to decreased pumping losses.

Interesting. I've never heard this before....Can you elaborate a bit?

Fuel Economy Study (Ethanol blends versus std. gasoline)

Reply #14 – January 05, 2009, 06:10:19 PM

Actually, let me think about it some more. I may be wrong.