Ethanol Blends can Provide Better Fuel Economy than Gasoline

Recent research findings show that mid-range ethanol blends - fuel mixtures most likely between E20 and E30 - can in some cases provide better fuel economy than regular unleaded gasoline, even in standard, non-flex-fuel vehicles.

Previous assumptions held that ethanol's lower energy content directly correlates with lower fuel economy for drivers. Those assumptions were found to be incorrect. E20 and E30 ethanol blends outperformed unleaded gasoline in fuel economy tests for certain autos. The tests were conducted using four 2007 model vehicles: a Toyota Camry, a Ford Fusion, and two Chevrolet Impalas, one flex-fuel and one non-flex-fuel. Contrary to Btu-based estimates of fuel economy for ethanol blends, three of the four vehicles tested achieved their highest fuel efficiency not on gasoline, but on an ethanol blend. Mid-level blends of ethanol E20 (20% ethanol, 80% gasoline) and E30 (30% ethanol, 70% gasoline) offered the best fuel economy in these tests.

• E30 offered better fuel economy than gasoline (a 1% increase) in both the Toyota and the Ford.
• E20 offered better fuel economy than gasoline (a 15% increase) in the flex-fuel Chevrolet.
• The non-flex-fuel Chevrolet more closely followed the Btu-calculated trend for fuel economy, but did experience a significant improvement over the trend line with E40 (40% ethanol, 60% gasoline), indicating that this may be the “optimal” ethanol blend level for this vehicle.

In addition to the favorable fuel economy findings, the research provides strong evidence that standard, non-flex-fuel vehicles can operate on ethanol blends beyond 10 percent. The three non-flex-fuel vehicles tested operated on levels as high as E65 before any engine fault codes were displayed. The Ford Fusion operated without problems on E45, the Toyota on E65, and the non-flex-fuel Chevy on E55.

The new study, cosponsored by the U.S. Department of Energy and the American Coalition for Ethanol (ACE), also found that mid-range ethanol blends reduce harmful tailpipe emissions and that vehicles without any adjustments can operate well on higher ethanol blends than previously thought. Emissions results for the ethanol blends were also favorable for nitrogen oxides, carbon monoxide and nonmethane organic gases, showing an especially significant reduction in CO2 emissions for each vehicle's "optimal" ethanol blend.

The University of North Dakota Energy & Environmental Research Center (EERC) and the Minnesota Center for Automotive Research (MnCAR) conducted the research. Researchers used the EPA Highway Fuel Economy Test (HWFET) to examine a range of ethanol-gasoline blends from straight Tier 2 gasoline up to 85 percent ethanol. All of the vehicles got better mileage with ethanol blends than the ethanol's energy content would predict, and three out of four actually traveled farther on a mid-level ethanol blend than on unleaded gasoline.

The full final report can be found here.

These tests possibly eliminate one of the main critisisms of ethanol, reduced fuel economy. The results were especially promising on the flex-fueled vehicle.  If these results can be replicated on other vehicles, especially flex-fueled vehicles, ethanol may be a more viable fuel than many critics believe.  Ethanol, plus otherbiofuels, are not the entire answer to our liquid fuel problems, because they could only meet about 30% of our needs (if cellulosic ethanol is included and our food supplies are not to be impacted), but they could be a less expensive solution in the intermediate term until hybrids, plug-in hybrids and all electric vehicles become more affordable - mainly due to decreased costs of batteries in the future. Flex-fueled vehicles are not significantly more costly than standard vehicles. Ethanol still suffers from its capability to absorb water, which makes transportation and storage more difficult.

Comments

[Kit P]

It is nice to see independent research provide better than expected results.

The most logical of the anti-ethanol arguments have been the lower energy value. It would appear that modern engines can take advantage of higher octane value of blends.

[Lad]

It is my understanding that flex cars are optimised for 87-92 octane gasoline and that a mileage penalty is the result of running the car on ethanol. I suspect that any mileage gains using ethanol blends are the result of some sweet spot in the original gasoline engine design. And, I suspect this sweet spot varies with each engine brand.

It seems to me that if an ICE is optimised for ethanol, running gasoline could also produce the same kind of results, i.e., a reduction in mileage.

This begs the question for mass marketing: Will we need to mix the gasoline and the ethanol in a predetermined percentages at the pump for maximum mileage? Interesting question, Hey What?

[Diodor]

" Will we need to mix the gasoline and the ethanol in a predetermined percentages at the pump for maximum mileage? "

You mean, blend it at the pump, depending on the car?

[Tim]

Actually I think that one brand or gasoline did let you blend it at the pump. They had regular and high octane and you could have the pump blend about six intermediate octane levels. Any one as old as me remember what the brand was?

[Kit P]

Sunoco is a brand in the midwest. I always considered blending a gimmick so I Sunoco was never my first choice. Last year I happened to stop at a Sunoco station on vacation and if I recall correctly the option was available for different mixes of ethanol.

[donb]

With the proper engine, substantial gains in milage could be achieved. I remember reading about a design that uses a high compression engine with a large amount of supercharging. This ordinarily would require high octane fuel. The design instead uses a dual fuel injection system - standard port injection of gasoline for low loads (e.g., constant speed cruise), and direct cylinder of pure ethanol for high loads (e.g., accelerating or climbing hill). For medium loads, both injection systems in operation to adjust the octane needed.

Ethanol (and methanol) is good for the direct injection system. It has a high octane rating, plus it has a high heat of vaporization, which cools the highly compressed air and thus reduces the necessary octane. The fuel consumption is heavily weighted towards gasoline due to normal driving conditions, but efficiency is increased up to 20%.

The system will probably never see the light of day, as apparently the EPA is quite anal about dual fuel systems, aswe stupid drivers can't figure out that we need to add two fuels, not just one. Seems to me that all it would take for the average driver is to run out of ethanol just once - the resulting poor performance would be a real slap to the side of the head.

[Cyril R.]

If this is true for most (flexfuel) vehicles then this is excellent news.

Considering the general agreement on the feasibility of a bioethanol portion of 20-30% of total gasoline consumption. And that's with current technology.

[thecase]

Gas = 116,090 BTU/Gallon
Ethanol = 76,000 BTU/Gallon

How could a similarly efficient engine get greater economy from Ethanol?

[thecase]

Gas = 116,090 BTU/Gallon
Ethanol = 76,000 BTU/Gallon

How could a similarly efficient engine get greater economy from Ethanol?

[Danzig]

Would we all like to accept this information as fact? Of course.

Are we all grown up enough to understand that this information is presented by strongly biased sources? We should be.

The "study" is funded by the American Coalition for Ethanol. The research is performed by two state agencies (North Dakota & Minnesota)which are major ethanol producers.

Thoughtful bloggers will celebrate quietly, but they will demand unbiased third party confirmation of this information.

[Kit P]

Danzig, you are a cowardly sleaze ball! What a cheap shot. Rather than infer people are lying why not make an effort to show how they are lying.

Again, this was independent research. Of course the ethanol industry paid for it. Of course the ethanol industry picked some place where they might get an honest answer.

I will be happy to apologize to Danzig if he makes the effort to provide us an analyses of the study. Since I read the report, I am not too worried about hearing back from Danzig.

[donb]

thecase asks:
How could a similarly efficient engine get greater economy from Ethanol?

Lad essentially answers the questions: I suspect that any mileage gains using ethanol blends are the result of some sweet spot in the original gasoline engine design.

This is exactly it. However, the sweet spot varies with load, rpm, temperature, alititude, humidity, and many other variables. The trick is to run high compression to get the most efficiency from an engine (diesel engine, anyone?). However, for a conventional gasoline engine, high compression demands high octane, though only at high load. During cruising, engine load is low, so high octane is not needed.

This is the beauty of the double fuel system engine I mentioned previously. It has high compression for efficiency, and the fuel system delivers the octane needed at the moment for the engine to run without pinging. In addition, due to the high amount of turbo boost, a small engine can deliver the same power as a larger conventional engine. This reduces throttling loss (more efficiency), and saves weight and space in the vehicle (more efficiency).

[Danzig]

Kit P: Goodness! Such hostility. Missed your meds, huh?

Where did I suggest anyone was lying? I simply suggested that we all need to think for ourselves and always be skeptical about the info we receive in press releases. We need to corroborate the things we read, rather than accepting every written word as the absolute answer.

This is precisely the suggestion that you make in most of your posts, Kit. Suddenly, you think it's a bad idea?

[Kit P]

“Where did I suggest anyone was lying?”

Right here,

“Would we all like to accept this information as fact? Of course.
Are we all grown up enough to understand that this information is presented by strongly biased sources? We should be.
The "study" is funded by the American Coalition for Ethanol. The research is performed by two state agencies (North Dakota & Minnesota)which are major ethanol producers.”

The thing is Danzig, as a skeptic I read the report looking to see if the research organization was independent of the funders and following methodology that would get independent results before I called it independent. This Danzig is the difference between a skeptic and a cynic.

Danzig on the other hand is just asking loaded questions and pretending that he is not making a inference about the truthfulness of the authors.

When I said Google was green washing, I provided evidence. So yes, Danzig I am hostile to cowardly slugs. Rather than suggest that I need medication, you could have provided a logical argument of why you are skeptical after reading the report.

[Jose Felix Silva Junior]

What Brazil has been doing for many years?
Using a blend of 25% of anhydrous ethanol in gasoline, without modifications in the cars engine.
Other countries are "trying" to use 5% to 10% of ethanol.
The funny is that a lot of people does not believe and says

[Bill Hannahan]

Kit P. I was not quite as happy with the report as you. It did not answer the most important question.

Was it a blind test? That is, did the people running the test know what was in the tank?

If you and I were running the test and wanted to make ethanol look good we could find some tricks to make it burn more gasoline, for example.

1 Be more aggressive with the throttle and brake while staying within the test envelope.

2 Manually shifting at higher rpm.

3 Dragging the brake lightly during the test.

Assuming everything was on the up and up, the data indicates some anomalies in the computer mapping for these engines. For example, going from e30 to e20 the flex chevy mpg improves 22%.

They offer no explanation for these data. To get the answer we would have to look at cylinder pressure vs time, spark timing and fuel flow to find out what is really going on.

An engine optimized for gasoline burning gasoline should deliver substantially more energy per gallon than an engine optimized for ethanol burning ethanol.

For mixed fuel engines it is up to the creativity of the engineers to come up with the best compromise. Perhaps flex fuel vehicles should be EPA mpg rated for two or more mixtures.

It is interesting but I don’t think we can draw any general conclusions from this data.

[Kit P]

“It is interesting but I don’t think we can draw any general conclusions from this data. “

Bill H, I can. There may be a benefit when buying higher blends of ethanol. Like Bill I would be interested in seeing more testing.

While Bill explains how dynomoniter testing could be biased by tricks, this is not the same as actually showing it was biased.

[amazingdrx]

A study funded by ethanol interests? How many car models were dumped from the test results to get this favorable outcome.

That is how drug company testing is done for drug safety now. Results that are not compatible with the expected outcome are simply thrown out of the data as anomalies.

Science is for sale. and ethanol boosters have plenty of loot from subsidies. Some verification involving tests on many more car models would need to be done, by independent scientists.

[Kit P]

A study reports better than expected results showing lower environmental impact for a product. After going back and carefully reading the study, and supported by others here who have provided reasonable explanations, I find no reason to not accept the finding.

The rant provided by amazingdrx is not very good. He meeds to work in the words Bush, Chaney, ADM and Halibuton.

Maybe someone can explain the need to reject any good news about the environment and cling to pixie dust solutions.

[Mohsen Mohimani]

I have Toyota Praise. My local gas station switched to ethanol 10. My gas mileage has gone down by 4 mpg. If we are consuming more gas, we are polluting more. Are we really saving anything?

[Mohsen Mohimani]

I have Toyota prius. My local gas station switched to ethanol 10. My gas mileage has gone down by 4 mpg. If we are consuming more gas, we are polluting more. Are we really saving anything?

[Russell Westfall]

If biofuels are so great, why isn't farm machinery rolling on them - totally?

If this were the case, the most important sector of our economy would be weaned from oil, and transporting yields to market could be the next step.

[Garko Novis]

buying gas has become a major investment decision, as in "do i invest in some food so i can get thru the day or some gas so i can get where i have to go?" It should never be this way but it is. But that doesn't mean we have to just suffer. There is a real solution in Water4Gas and you owe it to yourself to check it out! http://water4gasstreetdemo.usafastway.com

[John O]

i live in Oregon. I have a 94 Honda Accord. I was getting 30 MPG on regular UL before my state went to E10. Now I get 26.4-26.7 MPG on regular E10. On the UL premium non ethanol I get 30-30.5MPG. on a test of Premium E10 I get 27.4-28.5MPG. For the price, the Premium E10 is best even though it has less fuel economy than non ethanol.

[Kit P]

How controlled was your data?
Two friend who live in an area that does not have ethanol blends told me they notice much better fuel economy with E10 than they expected in their Ford (Mazda under the hood) or Toyota (93' Camry). However, I tend to discount data that is collected without controls such as wind speed.

[Edward C]

I drive a 95 Ford Crown Victoria and usually drive carefully to optimize my fuel economy. I was surprised when I bought it last year to get fuel economy of 30 to 31 on a regular basis, including one trip from Chattanooga, Tennessee to Front Royal Virginia on a single tank of gas (all Interstate driving) in which I got 31.4 mpg. However, as the gasoline in the area has changed to E10, I have been unable to get more than about 28 mpg under the same driving conditions (the same regular commute, the same season and temperatures). Don't doubt the personal experiences of the many drivers who report reduced mpg of typically anything from 10% to 20% on E10. Use of E10 saves us nothing in practice because the extra alcohol only occupies space in the tank without providing any extra miles. Meanwhile, more fuel is burned to produce and deliver it. If each person drove a car that was optimized for E10 then use of E10 might be useful. As it stands, very few of us drive flex fuel vehicles and for all of us requiring the use of E10 is a boondoggle.

If you carefully examine the study it is clear that if you are going to use a gasoline/ethanol blend to maximize fuel efficiency, the vehicle engine must be optimized for the particular blend that is used, or else go to the more complicated duel fuel system suggested above. otherwise the fuel economy will be reduced whenever the actual blend does not match that for which the vehicle was optimized. Since most of us do not now drive cars that are optimized to a gasoline/ethanol blend, its use is going to increase fuel consumption.

Better to let corn be food for the world than to do it this way.

Yes the Brazilians have successfully used ethanol as a fuel using sugar cane (not a food providing essential nutrition). We should first understand how they did it including any modifications to engine design.

[Kit P.]

So Edward, you enjoy eating feed corn? Just a few years ago feed corn was being sold for home heating in pellet stoves.

And Edward, how much sugar cane do they grow in Iowa?

Biofuels is an interesting social experiment. The first step was to see if we can replace 5% of the oil we import with biofuels. Now corn growers are paying taxes on what they produce instead of getting subsidies to stay in business. The experiment is working better than expected. Congress has increased the goal.

Now Edward, if you think we should base national policy based on your experience commuting in an old Crown Vic, do I need to point out the fallacy of your logic.

I have been following the biofuel industry for many years. The industry told Clinton for years what it needed to move forward but it fell on deaf ears. Bush listened and the 2005 Energy provided a mandate and a PTC.

Since the social experiment is working, clearly it is not a boondoggle.

[Discount Furniture Los Angeles]

Well than... lets get some ethonol-blends fueling stations out there.

[honda lease los angeles]

Well if ethanol blends are better we need to keep working on this!! Running out of gas anyway.