Why can't we use e85 fuel in our car why do we have to buy a special car?

Question

Why can't we use e85 fuel in our car why do we have to buy a special car?

Answer 1

It's easy to calibrate a car for E85 (85% ethanol 15% gas).  It's easy to calibrate a car for gas.  

What's hard is calibrating it for any random "blend" of those two fuels.  What happens when you have 1/4 tank of gas,  and you fill up with E85?  You really have more like E62 (62% ethanol 38% gas), which requires a different calibration than either E85 or gas.   The fuel system has to be able to dynamically make those adjustments on the fly.  On a modern OBDII feedback system, it's just software in the PCM.  But it's complicated software, and it wouldn't be easy to homebrew.

It might also require somewhat different sizing of the fuel injectors due to the need to inject more E85 than gas.

It also may require making engine internal parts corrosion-resistant, as E85 is somewhat more corrosive than gas.

Answer 2

Unfortunately, many older cars are incompatible with this type of fuel, due to the engine design and features. Perhaps eventually they will be able to modify cars so that they are able to run on this fuel, but until then, those of us who have these cars will have to use the regular fuels. Another downside to e85 is its limited availability at this point. I'm sure as it's use becomes more widespread, automobile manufacturers will have no choice but to do something about it.

Answer 3

E85 is 85% Ethanol.

All cars can be run on E10 which is 10% ethanol.

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It takes 35% more ethanol to deliver the same power as gasoline.  This means instead of a 10 gallon fuel tank to go 300 miles you will need a 13.5 gallon tank.

It also means you'll need a motor that is 35% more powerful to achieve the same performance as a gasoline driven car.

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As for decreasing our dependence on imported oil:

It takes 1.2 barrels of oil to make the equivalent ethanol to replace one barrel of oil.   The farmer uses diesel powered machinery to grow and harvest the corn, diesel powered trucks transport it and what source of power is used to transform the corn into ethanol?

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Should we also talk about all the water needed to run an ethanol plant?

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Ethanol, being lighter needs different fuel injectors and because it burns so much slower then gasoline the timing has to be different.

This means a different cam shaft and timing gears.

You also need a different intake manifold.

And a different exhaust system because the back pressure and flow is so different.

E85 is very corrosive so you'll need a different fuel tank, lines etc.

In fact, E85 is such a pain to transport it can't be transported except in special tanks and not by pipeline as gas and oil are.

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Unlike gasoline which has to be stored in a vented tank, Ethanol has to be stored in specially vented tanks.  Why?, because it's basically alcohol and it evaporates into the air at less then room temperatures.

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Buy $50 worth of Ethanol, store it in any old gas can, and a week later it's gone!

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Basically,, I think Ethanol is not the Answer to our problems.

I'm thinking Hydrogen for heavy transport and electric for everything else.

Only Motorcycles would continue to run on gas.

Answer 4

The company i represent has a patent on a hydrogen fuel cell for any car that will increase fuel milieage by 50-100% garanteed.  [e-mail] and i will forward the details.

Answer 5

Because Ethanol is C2H5OH.  The "O" is oxygen.  Since we have "free" 21% oxygen in the air already, the extra "O" in the ethanol, just reduces the effective energy density of the fuel by about 25-30%, because that one "O" is the heaviest element of the bunch.  

Because of this, when a "flex fuel" car senses extra oxygen in the exhaust, it increases the "pulse width" of the injectors, so 25-30% more fuel can be injected so there is a stochiometric ratio available.

Rather easy to do, usually cost car manufacturers less than $100 bucks to make a car flex-fuel, and $75 of that is the "flex fuel" decals and the yellow gas cap!

Answer 6

2 issues,

1. E85 has a higher octane rating than E10 or non-alcohol enhanced gasoline, which means that you need to have your timing tuned to the slower burning fuel. Also E85 does not have the same energy content as E10.

  See the citation below for an explanation about octane but the quick and dirty is that the higher the octane rating the less explosive the fuel is.

2. High alcohol concentrations can cause some rubbers, plastics and certain metals to corrode and actually disolve. This happened in the early days of E10 when certain rubber fuel lines would literally disolve. It can also affect the magnesium and aluminum parts of your car.

So in a car less than 20 years old you probably need a different computer chip, some tuning changes and make sure that none of your parts will disolve in E85. If your car is older than 20 years forget E85 and apply for collector plates.