Can uncombusted ethanol be removed before it is expelled from the tailpipe?

Question

One of the concerns with ethanol, either as a fuel additive or as a starting material in biodiesel, is uncombusted ethanol will breakdown into compounds which will produce ozone. Is it possible to equip exhaust systems with something analogous to a catalytic converter to cut down on the predicted ethanol levels?

Answer 1

One benefit of Ethanol is that it "burns cleaner."  Part of the reason behind this is that it burns more completely in a standard gas combustion engine, less ethanol makes it into the exhaust system.  Also, current catalytic converters are designed to handle ethanol.

Answer 2

It's already removed - this problem was solved decades ago by emission control systems.  The computer control systems of modern cars inject fuel very precisely, and they prevent a rich condition that would allow uncombusted fuel to leave the engine.  In the rare edge conditions where some does get by, the catalytic converter oxidizes it.  

To the best of my knowledge, methanol not ethanol is used in biodiesel production, though I suppose in principle ethanol could be used. Vegetable oil is a very long carbon chain made up of two shorter carbon chains called esters.  Methanol is an extremely short carbon chain (1 carbon is as short as it gets ;)  The methanol and veggie oil molecules are each split in two, and they swap halves, so each ends up with one ester.  That makes the carbon chains shorter, and the fuel thinner.

Answer 3

Of course.  You're just talking about an engineering challenge.  The question is, what will it cost and how well will it do it.