Will the New Ethanol Blend Tank My Ride?

Re:Will the New Ethanol Blend Tank My Ride? by ars on Tuesday December 25, 2012 @04:38PM (#4967167)

Ethanol also reduced MPG.

So to compares prices per gallon you need to derate the E15 (and the E10).

Does anyone have the numbers? Like 1 gallon of E10 is equal to .9 gallon of E0, etc?

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by greenyoda on Tuesday December 25, 2012 @04:50PM (#4967201)

"Vehicles will typically go 3–4% fewer miles per gallon on E10 than on straight gasoline."

Source: http://www.fueleconomy.gov/feg/ethanol.shtml

[ Parent | on HN ]

[deleted]

Re:Will the New Ethanol Blend Tank My Ride? by hatberet on Tuesday December 25, 2012 @05:45PM (#4967328)

Ethanol has a lower density than gasoline. So, although it has a similar mass-specific energy content, the volume-specific energy content is lower. Ethanol has a greater resistance to ignition than gasoline. But, since consumers buy gasoline in grades based on the octane rating (usually (RON+MON)/2), you don't see any octane benefit in your tank and do get reduced energy content.

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by jspthrowaway2 on Tuesday December 25, 2012 @05:40PM (#4967313)

It's a scientific fact based upon the free energy content of the same amount of gasoline versus the same amount of ethanol. Ethanol just doesn't have as much energy as regular gasoline. If you've observed the opposite effect, you're experiencing some kind of confirmation anecdote. I can almost promise something else is at work, such as less wind pushing on the nose of your car, different temperature, tire pressure, hills, something.

E85 is really bad, and will cost you 20-25% of your MPG compared to burning the equivalent amount of gasoline.

EDIT: The U.S. government publishes figures more conservative than what I just said, based on the link above me that I just read. They cite NREL/TP-540-43543[1].

[1]: http://feerc.ornl.gov/pdfs/pub_int_blends_rpt1_updated.pdf

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by sliverstorm on Wednesday December 26, 2012 @03:41AM (#4968647)

It's a scientific fact based upon the free energy content of the same amount of gasoline versus the same amount of ethanol. Ethanol just doesn't have as much energy as regular gasoline.

This by itself is meaningless. Diesel also has less energy than regular gasoline, yet diesel vehicles can generally beat equivalent gasoline vehicles in terms of mpg. There are more factors than simply energy content!

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by ars on Wednesday December 26, 2012 @06:50AM (#4968941)

> Diesel also has less energy than regular gasoline

That's not correct, it has more.

By weight it's identical, and by volume (i.e. gallon) it has about 12% more energy than gasoline.

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by sliverstorm on Wednesday December 26, 2012 @04:20PM (#4970966)

Whoops! Well, anyway, I think my point still- energy content is not the only factor- as diesel can get much more than 12% improved fuel economy. Diesel runs at much higher compression ratios, which is a good part of the increased economy. There's other things too, like the lack of a throttle plate which reduces pumping losses.

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by ars on Wednesday December 26, 2012 @07:12PM (#4971653)

Ethanol is being operated in the same engine as gasoline.

[ Parent | on HN ]

Re:Will the New Ethanol Blend Tank My Ride? by jspthrowaway2 on Wednesday December 26, 2012 @08:42PM (#4971909)

That's correct, hence my point. I'm not comparing to anything else, I'm thinking of the Flex Fuel engines that can use E85 and regular gasoline.

[ Parent | on HN ]