Ethanol is killing gas mileage

[brianl703]

Originally Posted By: glennc
A carburetor has a "dumb" air/fuel ratio that is set and then remains fixed.


Some carbureted vehicles have an oxygen sensor and a mixture control solenoid. Examples include the 1986 Camaro Z28 and the 1986 Dodge Omni. These will indeed adjust the air/fuel ratio just like a fuel injected system will.

 

[Gary Allan]

Originally Posted By: milwaukee
That was Bartles and James.



Yes ...either way, it reminded me of that little thingie

Thank you for your support

 

[Junior]

Originally Posted By: swalve
The problem isn't energy content- Diesel contains less energy per volume, but gets better MPG.

The problem with ethanol is two-fold:

1) Pure ethanol has a very high octane rating. (It's racing gas, after all.) When they blend it with gasoline, they use gasoline with a lower octane rating to end up with a mixture that's 87. Not only are you burning ethanol with lower energy content, you are burning cheaper, worser gasoline.

2) Engines tuned for gasoline don't burn ethanol as well as they could. To get ethanol to run right, you need advanced timing and a higher compression ratio. The auto manufacturers aren't going to build an engine that does this because if Joe Consumer puts regular 87 octane in it, it will destroy itself. It's possible to do this with existing technology- the GM supercharged engines retard boost and timing when they have 87 octane in it. They could do this with a flex-fuel vehicle if they wanted. But I don't think people will buy a regular vehicle that *requires* E85 or 93 octane.

I'm currently experimenting with my Dodge Spirit- there's a station nearby that has e85, so I started using it and bumped up the timing (it still has a distributor). I haven't been doing it long enough to get mileage results, but I believe they will be comparable.


No, diesel has a higher energy density. (of course the energy density is going to depend on the fuel density which varies with temp but we won't get into that)

Typically:

No.2 diesel has about 139,000 BTU/Galllon
Gasoline has about 125,000 BTU/Gallon

Plus, diesel engines run a higher compression ratio and as a result have a higher thermal efficiency.

Most modern fuel injected vehicles can run just fine with 20-30% ethanol with no problem.(there is a University study from UND and Minnesota I think) The fuel trim can adjust. I have run E20 in both my 04 accord and 98 f-150 without issue. You don't have to increase the compression ratio. Kind of like saying you need to increase the compression ratio to run 93 octane in an engine designed for 87. To get performance gains you need to but not for it to run.

I agree and have measured, the difference between 100 gasoline and E10 is about 3-5% in everything I have bothered to check.

 

[Gary Allan]

It still appears to reach the cost:energy balance ..much depends on what ethanol costs at the pump. It's currently trading at about $2/gallon (if I reading it right). You would need $3.18 worth of ethanol to replace a gallon of gasoline ..at the commodity traded price.

What's gas cost at the producer level? If it's less than $3/gallon ..then ethanol produces absolutely no savings in energy importation. That's outside of all the secondary impacts of such high levels of ethanol production. Inflation isn't always that bad ..or so the economists say

.

 

[KA426]

I've never checked it because my mileage sucks no matter what I put in the tank of my 4.7 Dakota.

 

[swalve]

Originally Posted By: Junior
No, diesel has a higher energy density. (of course the energy density is going to depend on the fuel density which varies with temp but we won't get into that)

Typically:

No.2 diesel has about 139,000 BTU/Galllon
Gasoline has about 125,000 BTU/Gallon


My bad- I knew that, but happened to see the opposite on another site and only remembered that when writing this.

Originally Posted By: Junior
Plus, diesel engines run a higher compression ratio and as a result have a higher thermal efficiency.


That's part of my point- gasoline, especially 87, can't run at any higher CR. But ethanol can. So it's not exactly right to say the problem is ethanol- the problem is with trying to run it in engines not designed and tuned for it.

Originally Posted By: Junior
Most modern fuel injected vehicles can run just fine with 20-30% ethanol with no problem.(there is a University study from UND and Minnesota I think) The fuel trim can adjust. I have run E20 in both my 04 accord and 98 f-150 without issue. You don't have to increase the compression ratio. Kind of like saying you need to increase the compression ratio to run 93 octane in an engine designed for 87. To get performance gains you need to but not for it to run.

I agree and have measured, the difference between 100 gasoline and E10 is about 3-5% in everything I have bothered to check.


Yes- it will run and the engines will adjust for it. Maybe I'm oversimplifying it, but performance gains should also lead to more efficient fuel consumption. More power produced means less throttle to make the same speed.

I'd also be interested in seeing what running lean does with ethanol versus gasoline.

 

[Junior]

Yes, I agree with you. An engine disigned to run on ethanol will produce more power than one deisgned to run on gasoline. However, I don't think you ever get to the same miles per gallon range.

 

[JTK]

Well there you have it! Think of Bartles and James next time you fill-up. Non E10 is so rare in my area, I don't notice the MPG drop. I know the drop is there though, the very few time I can get a "100%" gas fill-up.

Joel

 

[Norm Olt]

More like a minimum reduction of 10%: more in some vehicles. All to fuel (pun intended!) the over 100% rise in commodity prices seen over the last year.

Worse gas mileage = MORE fuel burnt per mile, and this is all done in the name of "reducing the evil CO2" (without which there would be no photosynthesis and no life "as we know it" on the planet).

Talk about the law of diminishing returns! If you operate a 2005 or newer Civic in the LA basin your exhaust is already cleaner than the ambient air!

(NO)Cheers!

 

[Junior]

I'm sorry, I just don't agree on your 10% number. I don't think your Penske rental truck is a good test vehicle.

BTW, have you checked the price of corn lately? It has dropped a lot in the past 8 weeks.

 

[Bamaro]

Originally Posted By: Norm Olt

Worse gas mileage = MORE fuel burnt per mile, and this is all done in the name of "reducing the evil CO2" (without which there would be no photosynthesis and no life "as we know it" on the planet).

Ethanol is not for reducing CO2, it is about no net gain in CO2. It is a yearly recycling of CO2 as opposed to millions of years.

 

[Cory]

I have no problems running ethanol and more often than not, get better fuel economy with it. Now I've done plenty of driving and testing fuels. After all, I drive over 26K annually with my 2000 Chrysler 300M and if you add in my wife's driving with the same model vehicle (4 years newer), we're talking over 50K miles driven annually with information relative to octane and ethanol blends.

Here's a test with data I provided to my car club from back in early June of this year.
Quote:
Using the prices of a week ago...
$3.23 / 89 Octante (10% Blend) ------ $3.33 / 87 Octane ----- $3.43 / 91 Octane

Avg. mpg
---------------28.9------------------ -----------27.6----------- --------------29.1------------

Cost per mile
-------------11 cents--------------- ---------12 cents--------- --------------12 cents-----------

I'll be going back to the 10% Blend. Not only because of the data and costs shown but also feel that I can get even better fuel economy with another week of testing. Once again, the week I tested the ethanol blend it was very windy.

More to follow....