[Article] Better Fuel Economy with Ethanol?

[solarguy]

Dear Duffman,

While you are correct about the food distribution problem, and the hunger it causes, it does not change that fact that the U.S. used to be a net exporter of food, and we recently became a net importer. Yes, the U.S. no longer grows more food than it eats. That is not just a distribution problem. Topsoil erosion and aquifer depletion are serious now, and getting more so, rapidly.

Why waste those difficult to replace ag resources just to make ethanol from corn?

troy

[Frank Lee]

The obvious solution is to keep growing the population.

Maybe one of the newborns will figure out a way to defy physics.

[shovel]

Originally Posted by solarguy

Dear Duffman,

While you are correct about the food distribution problem, and the hunger it causes, it does not change that fact that the U.S. used to be a net exporter of food, and we recently became a net importer. Yes, the U.S. no longer grows more food than it eats. That is not just a distribution problem. Topsoil erosion and aquifer depletion are serious now, and getting more so, rapidly.

Why waste those difficult to replace ag resources just to make ethanol from corn?

troy

Why not? We build cities on our best farmland... the los angeles basin used to be one of the world's most productive pieces of farm land and still would be if we hadn't paved it.

As a former almond farmer (parents farm, we lived and worked onsite) my opinion is that domestic agriculture has shrunk more because of economics than because of actual capacity to produce. It's just plain cheaper to buy food from countries with cheaper fuel and labor, and of course the awesome fact that I can buy fresh strawberries and peaches 365 days a year... every Chilean peach I buy in february is one less American cob of corn I'm going to eat.

Corn isn't the only way to make ethanol, everything from municipal waste here in phoenix to johnson and switch grass in the west and giant miscanthus in the southeast are being used to make the stuff. I just don't understand some peoples' aversion to making progress in fuels. To me the most attractive feature of going to ethanol is the millions of existing vehicles on the road can be converted rather than thrown away, the drivers already know how to fill their tanks with a liquid fuel (as opposed to gaseous or other fuels) , the fuel stations already have tanks and pumps and a delivery infrastructure that doesn't care what flammable liquid it's delivering, all in all converting the whole nation to ethanol seems the most painless of all available options and the greenest since we can just continue using all the equipment that's already out there and working.

[gone-ot]

...back to the original statement, and the facts:

.A/F -- gasoline (14.7:1), ethanol (9.0:1).......ie: 0.39 = (1 - 9.0/14.7)
BTU -- gasoline (116,090), ethanol (76,330)...ie: 0.66 = 76,330/116,090

...so, UNLESS the engine is specially modified (ie: flex fuel, wide-range-sensors or variable CR), switching from gasoline to ethanol takes a BIG hit twice:

1) in stoichiometic A/F ratio, which means almost 39% more FUEL by weight for same CID.

2) in energy content, which means amost 33% less ENERGY in the combustion process for the same CID.

...granted, things improve as the engine progresses from today's "standard" toward tomorrow's "what's possible," but NOT many of today's engines are so endowed!

[shovel]

Originally Posted by Old Tele man

...back to the original statement, and the facts:

A/F -- gasoline (14.7:1), ethanol (9.0:1)........ie: 0.61 = 9.0/14.7
BTU -- gasoline (116,090), ethanol (76,330)...ie: 0.66 = 76,330/116,090

...so, UNLESS the engine is specially modified (ie: flex fuel or variable CR), switching from gasoline to ethanol:

1) takes a BIG hit in stoichiometic A/F ratio, which means almost 61% more FUEL by weight for same CID.

You're correct but nothing "special" needs to be done, the vehicle just needs to assess what fuel is being burned and then have the injector capacity to shove more fuel through the injectors per cycle and use current standards for ignition timing to advance until just below knock. I have 2 vehicles in my driveway with very little mods that run perfectly on e85, have done so for tens of thousands of miles indicating no reason to suspect harm. Exhaust temperatures are similar between the two fuels when enough fuel is being burned which tells me that valves aren't being burned.


As for the burning more fuel by weight... to my knowledge nobody's contesting that. It's a different fuel with a different number of BTU's per pound, who would expect identical output per pound from a substance containing less actual energy per pound? What if I gave you a car that runs on your household greywater waste but only gets 1 mile per gallon? Would you complain about the MPG?

[gone-ot]

...you are missing the POINT, which is that NOT ALL engines achieve improved FE on ethanol blends!

...so, the carte-blanche statement that E85 gives better FE than E10 is strictly "local" (like politics and babies)...it's just ONE persons experience in a much, much larger arena of MANY differing results.


P.S.-- I corrected the A/F equation & value.

[shovel]

Originally Posted by Old Tele man

...you are missing the POINT, which is that NOT ALL engines achieve improved FE on ethanol blends!

..

Sorry, you are correct given the topic of this thread.

My argument was based on my assertion that it's OK to use more gallons of a physical substance if the net harm done by producing and consuming them is less than the other substance being compared, even if less of it is being used per work unit done.

[Lazarus]

Originally Posted by shovel

Sorry, you are correct given the topic of this thread.

My argument was based on my assertion that it's OK to use more gallons of a physical substance if the net harm done by producing and consuming them is less than the other substance being compared, even if less of it is being used per work unit done.

That is the million dollar question. It's very debatable that corn based ethanol is doing less harm.

[shovel]

Originally Posted by Lazarus

That is the million dollar question. It's very debatable that corn based ethanol is doing less harm.

fair enough, what about cellulose based ethano that doesn't use any food sourcel? or that made from municipal waste which reduces landfill inflow and is net energy positive?

and of course matters of environmental harm aside, it seems the general consensus that petroleum is a finite substance, we've gotta bridge off it eventually right?

[Frank Lee]

Bridge off it? Like that bridge in Alaska?

DRILL BABY DRILL!!!