10% Ethanol gas cuts mpg ?

If you hypermile and accelerate gradually - the MPG hit from E10 will be mitigated.
If you accelerate hard and frequently - the MPG hit from E10 will be amplified.

 

Huh? The MPG hit remains 3.3% no matter how you drive*. Hypermiling gets you higher mileage regardless of fuel, and driving poorly gets you worse mileage regardless of fuel.

*- Actually, of course, the GPM difference remains the same, but I hope everyone understands what I am saying.

 

What I am trying to say is that effects of the lower energy density of E10 is more pronounce at higher speeds/harder accelerations because fuel consumption increases exponentially not linear with vehicle speed and acceleration rate.

fuel efficiency varies depending on the driving conditions.
fuel efficiency appears to degrade linearly at low speeds but at high speeds it degrades exponentially.
A weaker fuel degrades exponentially at high speeds faster than a stronger fuel source
For any fix distance travelled - the force require to move a fix mass is determined by the acceleration.
It's Newton's 2nd law of motion: Force = mass * acceleration = mass * (delta velocity/ time )
The kinetic energy to move the Prius of mass X a fix distance X
Force * x = 0.5 * mass * (velocity ^2)
If x and mass is constant then Force = (.5 * mass/x) * velocity ^2
hence the force require rises and falls with the velocity the higher the top speed the more force is required
As velocity approaches 1 the difference in force required to go a distance X becomes less and less.
That is to say that if a fuel source has X energy that as the velocity increases the
energy requirement increase by the velocity square and so a fuel consumption increase exponentially not linearly. When fuel consumption increases exponentially any
increment decrease in it energy density is magnified exponentially as well.

 

...you are getting better MPG than me...getting better requires hypermiling techniques you can see posts here and videos on YouTube. Ethanol probably costs us 1-2 MPG but is minor impact. As Corwyn said, EPA uses 100% gaso in their MPG tests due to high costs of testing they cannot test everything. I think it would be nice if Consumer Reports or some car lab would test E10 vs. E0 for some typical vehicles. You can go to FuelEconomy.gov to read a little more about the EPA testing.

 

Several states now require 10% Ethanol blend all year long, and yes, Oregon is one
of them. I have no choice I have to use 10% Ethanol Blend.

The U.S. Government believes that 10% Ethanol is great, now they are thinking
about a 15% Blend, yeah, just what we all want, fewer miles per gallon and we
all believe we are saving the planet by going fewer miles on a gallon
of gasoline. Maybe its because I went to public school I
don't understand that logic.

Or that it takes about 1 1/2 gallons of diesel fuel to make one gallon of
ethanol. Now remember Ethanol has only 68,000 BTU's of energy
and diesel 135,000 BTU.

Just try to obtain a business loan with that plan.....

 

I have read some where that E10 cleans the fuel system. If that true?

 

Sorry, no. Energy required to move a mass goes up as the fourth power of the velocity. It is never linear and it is never exponential.

That is also beside the point. If one uses 1 gallon of gas to go 50 miles at 50 mph, one will need 1.03 gallons of E-10 to go 50 miles at 50 mph*. If one needs 1 gallon of gas to go 100 miles at 15 mph, one will need 1.03 gallons of E-10 to go 100 miles at 15 mph. In the first scenario, one is getting 50 mpg on gasoline and 48.5 on E-10, while in the second one is getting 100 mpg on gasoline and 97.1 mpg on E-10.

* - ignoring the increase in mass due to 0.03 more gallons of fuel, since we aren't doing rocket science here

 

Not only does the EPA use 100% gas, I've read that it's specially crafted in small batches under very controlled conditions to make sure that what they test with this year is exactly the same as what they tested with last year and the year before. I bet that process adds more than the typical 15¢/gallon upcharge for pure gas.

 

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Should not the total amount of energy required to move a mass be the Kinetic Energy formula which goes up by the square of the velocity not the fourth power?

KE = Net Force * distance = (1/2)* mass * (velocity ^2)

Despite the official standard difference in energy between gasohol and gas is suppose to be a constant 3.2% less, I experienced consistantly needing more than 3% more gasohol than regular gas on a 1990 Honda Accord LX Automatic to drive it the same way the real world - it was more like 7% more. Unfortunately - I am unable reconcile my real world data and experience with the theoretical equations at hand.

 

I was thinking another possibility for the 7% loss in MPG rather than a 3.2% in MPG from 10% ethanol gasoline is that some of the ethanol in the E10 had evaporated - escape from the fuel tank before it could be burned/used.

 

Someone probably knows the volatility of ethanol and gasoline, but my guess would be that they are close. The Prius goes to great lengths to ensure that no fuel evaporates. I don't expect that that changes due to E-10 vs Gas.

 

Actually, I appear to have misremembered, it is the cube (third power) of velocity.

Kinetic energy just tells you the energy in a moving mass. If that was the only issue, you could get to 65 MPH, and travel across the country with no additional fuel usage (and could recover it when you got to the other end). Energy usage goes in three main areas, heat in brakes, heat in tires and road, and wind (each with efficiency losses, of course).

Power = 1/efficiency * (1/2 * mass(car) * velocity^3 / distance between stops * regenerative brake efficiency + 1/2 * Density of air * frontal area * coefficient of drag * velocity^3 + rolling resistance * velocity)

 

Not only does 10% ethanol blends have less energy, but lower compression ratio gasoline engines are designed & built to use 100% gasoline most efficiently. Gasoline engine manufacturers like EPA to test their gasoline engines with 100% gasoline, & EPA does so. For a decade my 3 cars have shown 8%, 7% & 5% increases using 100% gasoline, instead of 10% ethanol blends. Other drivers(one having 115,000 miles of records) indicate increases of 10+%, using 100% gasoline. This is not rocket science. But it is good 100% gasoline lower compression ratio engine science. Ethanol needs higher compression ratio ethanol engines to get its efficiency. Furthermore, the ethanol industry has been caught blending too much ethanol into gas supplies, to the extent of 11%, 12%, 15%, on up to as much as 63%. The ethanol industry calls it accidents. But it is " accidents" making them lots of money. The oil industry likes ethanol blended into gasoline supplies. First, the growing ethanol industry uses a lot of oil to produce its ethanol. Second, 10% ethanol blends, as careful drivers performing careful records do & will show, does not cut oil consumption much at all, such as my records. Other records, showing 10% mpg losses due to 10% ethanol blends, determine NO actual fossil fuel cuts....that the ethanol is getting in the way of energy production (inside the engine).

 

Fortunately, the engine in Prius is high compression... 13:1

 

I tried E0 and only got about 1.5 mpg over E10 fill up. The cost...... Hold on to your panties!


.95 more a gallon!!!!!! I hate hate hate government forcing things down citizens throats and making decisions that line thier pockets no matter the cost to the people....... But at almost a dollar more a gallon for the very little mpg boost ill have to stay with E10....

 

Wow, around here it is usually only 10 cents extra for E0.

 

Yes, all else being equal, E10 DOES hurt your mpg when compared to gasoline with no ethanol. That being said, I've gone over 800 miles on one tank of E10 in my 2010 Prius more than once. Don't fret and just focus on your hypermiling techniques.