Oxygenates, additives and fuel economy. What can be done?

[TwoLostMinds]

Here in NJ we use oxygenated gas in the winter time.
If I understand this correctly....
Ethanol oxygenated gas doesnt burn as well as other additives and causes performance drops.
When the oxygenated gas is burned the O2 sensors tell the ECU that the mix it too lean and the fuel curve is adjusted dumping more fuel in to balance things out. The end result is slightly lower emmisions and a drop in fuel economy.
My MPG drops from 20.8 to 18.45 for most of the winter and on really cold days (lower than 30 deg) it falls to around 14 - 16 MPG. Are there any additives or modifications that can be done to a newer vehicle (2004 Hyundai Santa Fe 2.7 liter AWD) to combat this fuel economy loss?

 

[tblazed]

Got to keep after the politicians that came up with this. Write your congressmen and senators, ask them to explain how burning 10% more RFG because of the inherent reduction in MPG saves any oil or energy. The use of ethanol at 10% blend offsets any savings of non-renewable sources like crude. And might also ask why they base the use of RFG on old obsolete 1980's data.

 

[kenw]

quote:

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Originally posted by tblazed:
Got to keep after the politicians that came up with this. Write your congressmen and senators, ask them to explain how burning 10% more RFG because of the inherent reduction in MPG saves any oil or energy. The use of ethanol at 10% blend offsets any savings of non-renewable sources like crude. And might also ask why they base the use of RFG on old obsolete 1980's data.

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Oxygenated fuesl aren't meant to save any oil or energy. No one that I know of ever claimed they would.

they are strictly for reducing pollutants.

 

[Palut]

I'm lucky to not have oxygenated fuels in my county in the winter. I do everything I can to avoid buying gas in counties where its oxygenated during the winter. If you're near the border of a non-oxygenated area, you could vote with your money, and drive a little farther to buy good gas.

 

[ruking77]

Wow your loss is only app 11%. The loss can be up to 20%. In the earlier implementation days there was also a host of equipment failures! In addition, they are starting to document that burnt oxygenation causes greater health concerns over and above the burning of unleaded gasoline. It is probably not commonly known that burnt oxygenation is not mitigated by the catalytic converters, as is the unleaded regular fuel is. Also, the EPA for industrial purposes did years back ban the use and burning of oxygenation for at the time: " health" concerns. So why it is NOW ok (and has been for a time) for WIDESPREAD winter unmitigated burning is oxymoronic, anathema and disengenuous!

 

[slider]

>they are strictly for reducing pollutants.

The question is: do they really in the aggregate reduce pollution when the reduced fuel economy (which is because these special blends have overall energy) makes for more fuel consumed overall?

 

[ruking77]

I would think NOT! If it was why are we not pursuing power plants that only burn the oxygenation, full time!?

 

[TwoLostMinds]

Well, I dont know if Ethanol in our gas really reduces pollution. In NJ most of our pollution blows in from factories in the Ohio valley anyway. At least they did away with MTBE, too many people getting sick and our water sources getting contaminated. Those are arguments for another day in another forum.
Guess I'm lucky to only be losing 11% for most of the winter, but those 14 - 16 MPG tanks during the coldest days of the winter are agrevating.
I was just hoping that there would be a way to offset these loses with an aditive or a modification. I have heard that older carburated vehicles can fight the lose by rejetting, was wondering if we could do something with our ECU's to simulate this.

 

[farang]

If I buy gas from a gas station WITHOUT the "this station use oxygenerated fuel to......" label, is that mean the gas is WITHOUT those junk?

I am asking that because I read several post about a tanker deliver fuel to several gas station (only the additive is different).

In my area, within 1mi
Chervon - Oxy
76 - none
Costco - none
Mobil - none
Chervon - Oxy
Arco - Oxy
Shell - none
76 - Oxy

 

[MNgopher]

In terms of the MPG loss, while ethanol fuel will get lower fuel mileage than a non-oxy fuel, it can in no way be blamed for the entire MPG loss in the winter time.

Minnesota mandates the use of 10% ethanol blends year around. Yet I note my average fuel mileage in January in my F150 is 13.1 mpg, in September (likely the least air conditioner time for me!) I get 16.1 mpg, with an overall 115,000 mile 15 mpg average. Thus, from average, I see a 8.7% decrease in the winter (worst month), but net a 7.3% increase from average in my best month. Notice thats a 16% difference from best to worst. My Jeep follows a very similar pattern.

Yet, we have no change from oxy to non-oxy fuels here - thats a constant 10% ethanol year around.

My point is that while the oxy fuel will net a decrease in MPG, fleet testing generally shows the difference to be in the neighborhood of 2-4%.

The remainder of the large decreases in MPG are functions of other cold weather issues: increased drag from cold lubricants in all the bearings, transmission, etc..., increased run time in open loop warming up, decrease in air pressure in tires as a result of temp changes, etc...

The orginal question even notes a large decrease in temps lower than 30 F, yet that is still running the winter oxy fuel of that region. Lots of factors come into play.

 

[MNgopher]

quote:

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Originally posted by slider:
>they are strictly for reducing pollutants.

The question is: do they really in the aggregate reduce pollution when the reduced fuel economy (which is because these special blends have overall energy) makes for more fuel consumed overall?

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Previous studies I've seen on the matter do show a significant drop in pollutants, particulalry Carbon Monoxide, which was the initial target use of the oxygenates. Drops in pollution levels were on the order of 25% using an oxy fuel vs. regular fuel. Of course, this was on older equipment, and the gains were less under new equipment.

 

[MNgopher]

quote:

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Originally posted by ruking77:
I would think NOT! If it was why are we not pursuing power plants that only burn the oxygenation, full time!?

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Because an oxygenate is intended to modify a particular part if the combustion process, mainly by promoting a more efficient, cleaner burn. The oxygenate is not intended to be the main component in the combustion process, when used as an oxygenate. Not to mention the totolly differnt power applications...

E85 (85% ethanol/ 15% gasoline) is pretty readily available in this area for vehicles that have Flexible Fuel systems. Of course, with the ~20% fuel mileage penalty, the small difference in price (generally only 10-15 cents per gallon) is not enough to justify its use on a financial basis. Of course, in this fuel the "oxygenate" becomes the primary fuel.

 

[MNgopher]

quote:

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Originally posted by farang:
If I buy gas from a gas station WITHOUT the "this station use oxygenerated fuel to......" label, is that mean the gas is WITHOUT those junk?

I am asking that because I read several post about a tanker deliver fuel to several gas station (only the additive is different).

In my area, within 1mi
Chervon - Oxy
76 - none
Costco - none
Mobil - none
Chervon - Oxy
Arco - Oxy
Shell - none
76 - Oxy

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Depends on your state law. Being in California, I'd be willing to bet it ALL has it, thus no need for labeling all the pumps.

Minnesota does it different - the labeled pumps are the non-oxy premium pumps at select retailers, everything else has ethanol.

 

[ebaker]

From www.EPA.gov :
"Reformulated gasoline (RFG) is gasoline blended to burn cleaner and reduce smog-forming and toxic pollutants in the air we breathe. The Clean Air Act requires that RFG be used in cities with the worst smog pollution to reduce harmful emissions of ozone.

The Act also specified that RFG contain oxygen - 2 percent by weight. MTBE (methyl tertiary butyl ether) and ethanol are the two most commonly used substances that add oxygen to gasoline. Oil companies decide which substance to use to meet the law's requirements"
"At this time, about 30 percent of this country’s gasoline is reformulated gasoline, of which about 87 percent contains MTBE."

I believe most reformulated gasoline contains 6% MTBE. Since MTBE and ethanol contain about 1/2 the energy of gasoline, you should see a 3% gas mileage reduction.
I think my car gets worse mileage in the winter because it runs rich when the engine is cold.

 

[GT Mike]

Even with oxygenates, the fuel blended for winter use has less energy than the summer blends. They blend in more light aromatics (butane, heptane, etc.) to facilitate easy starting in cold weather, and this in turn reduces MPG considerably. The oxygenate really doesn't affect it as much as the overall blend itself does.

With my car which has an EPA rating of 19 city, 30 highway MPG, I can only get 23-24 MPG highway in the winter months and mixed with some in-town driving that average drops to the mid-high teens.

In the summer time, ethanol or no ethanol, I can easily see 30+ MPG on a straight highway trip, and usually see no less than 20 if there's a lot of city driving involved. The brand of fuel, not so much the addition of an oxygenate seems to have more of an impact on my MPG than the oxygenate itself.

 

[Palut]

quote:

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Originally posted by farang:
If I buy gas from a gas station WITHOUT the "this station use oxygenerated fuel to......" label, is that mean the gas is WITHOUT those junk?

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I called a Chevron hotline to find out in what Washington counties they sell oxygenated gas.

You're probably of out of luck Farang, as all gas sold in California is oxygenated. But I did read something on Chevron's site about them trying to develop a gas formulation that would meet California's air laws without oxygenates.

I really, really dislike oxygenated fuels, because each time I've filled up with them, I've gotten 2-4 fewer mpg. In one case, with some BP gas, I lost 6 mpg! 25 mpg on the highway instead of my usual 30-31. I'm disappointed when I see 25 in city driving! Here's a comparison of mileage I got on oxygenated and non-oxygenated gas on my last trip to Cali: Mileage comparison thingy .

I've also read (I can't remember where) that in any car with a working O2 sensor, oxygenated fuel does nothing but worsen gas mileage and increase emissions, because the computer already makes it run with the right mixture. Somebody please let me know if I'm wrong about that.

 

[GT Mike]

quote:

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Originally posted by Palut:
I've also read (I can't remember where) that in any car with a working O2 sensor, oxygenated fuel does nothing but worsen gas mileage and increase emissions, because the computer already makes it run with the right mixture. Somebody please let me know if I'm wrong about that.

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If that were true, you'd see your long term fuel trim (LTFT) reading toward the positive side to combat the erroneous lean condition being delivered to the O2 sensor. As it is, this does not happen. A vehicle that is in what I'd consider a perfect state of tune has a LTFT very close to 0%, meaning the fuel delivered to the engine exactly matches the tables programmed into the PCM, and there is no need for the PCM to add or remove fuel to continue to achieve a perfect A/F ratio.
I pay close attention to this when I'm scanning, and whether I'm running ethanol or not, I never see my LTFT vary more than +/- 0.5% from 0. The ethanol makes no difference, and the PCM doesn't need to "learn around" it.

 

[wileyE]

Palut, here in Kitsap ARCO is the only pumps labeled 10% ethanol. Everyone else gets fuel from Tacoma's Tosco (graded or un graded) or Tesaro terminals (one grade). Neither are oxygenated. Talk with the tanker truck drivers when you see them filling at the stations, after afew tell you the same thing you probably have good info. GT mike makes a good point about the vapor pressure being increased for the winter or cold temps. Not sure how much that effects milage?

 

[TwoLostMinds]

Ok...so we can all agree that winter gas reduces fuel economy. We also know that modern vehicles with computers that control emisions dont really need oxygenates. With our modern computerized vehicles (O2, MAF, MAP, etc. sensors)can we come up with a way to combat this fuel economy lose? Something to trick our sensors, adjust our fuel curve, etc?

 

[Palut]

quote:

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Originally posted by wileyE:
Palut, here in Kitsap ARCO is the only pumps labeled 10% ethanol. Everyone else gets fuel from Tacoma's Tosco (graded or un graded) or Tesaro terminals (one grade). Neither are oxygenated. Talk with the tanker truck drivers when you see them filling at the stations, after afew tell you the same thing you probably have good info. GT mike makes a good point about the vapor pressure being increased for the winter or cold temps. Not sure how much that effects milage?

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The Chevron people told me that they only oxygenate gas that's to be sold in King, Pierce, Spokane, and Clark counties. They also said that those counties only receive oxygenated fuels during the winter.

Where you are on the peninsula, you shouldn't have to worry about ethanol. I'm right in the heart of Thurston county, and don't have to deal with it either!