The point of more oxygen is to get more complete burn. If the burn were complete, there wouldn't be any polutants, only CO2 and H2O. Why do we put turbos and superchargers on? To get more air, specifically oxygen, into the cylinders. Without more oxygen, you won't get more heating in the cylinder. The atmosphere is mostly Nitrogen, with oxygen coming in at second, if I recall correctly, about 40%. The trick to forcing more air into the cylinder, is that more nitrogen gets forced in as well, making the NOX emissions higher as well. So by the fuel carrying it's own oxygen, you can reduce the NOX a bit.
As to the studies showing that ethanol is an energy loser, it all depends on which study you read, as there are plenty, and not all are from corn belt states, that show ethanol is an energy gain. Link here Stats can be twisted to show anything you want, so it is dificult to know which to believe, but when there are numerous studies that show a gain, reasonable doubt has to be raised as to which is true. Also, it depends on what all factors are added in. If you consider other products that also come from the production process, and add their value as well, there is more gain. It depends on the process to make the ethanol as well. There are plants being built that use no fossil fuels, rather the waste of the process is used to generate the heat of the process. Petroleum has it's waste products, and not only gasoline or diesel are the only prducts, so the same focus should be allowed to ethanol as well to get the full piucture. WHen the ethanol is made, it isn't specifically for only ethanol but rather, ethanol was originally a side product from the production of corn sweetener, and there is also the livestock feed as well... Back in the 70's when some of the studies were done, things were very inefficient, so it was a loss. I would bet that in the early days of oil production, things were pretty inefficient as well.

 

Couple of points.
1. IF the only thing in the combustion chamer were oxygen and gasoline then yes, the only byproduct would be CO2 and H2O. However, as you have stated, we are burning in an atmosphere that has a high percentage of N2 in it. If you put N2 into the reaction chamber, it's going to react. If the N2 combines with oxygen, it's stealing O2 from the reaction and you have incomplete burn of the gasoline. CO and unburned HCs result. As well as NOx.

2. NOx is produced under conditions of high heat and pressure. IC engines are more efficient the hotter the burn is. Hotter burn = more expansion of the gas in the combustion chamber = more force on the piston = more power out of the engine. If you could run higher combustion chambers and changed nothing else, you would get more power out of the engine and burn the same amount of fuel.

The first attempt at reducing NOx pollutants was to reduce combustion temps. This was accomplished by dilluting the intake charge with inert exhaust gas using the Exhaust Gas Reciculation devices. By filling some of the combustion chamber with inert gas, the combustion temperatures were reduced and formation of NOx was reduced. Power also went down.

3. Do we put tubos on to get more air or more oxygen in the cylinder? By putting a larger volume of gas in the cylinder, compressing it to the same compressed volume and then heating it, we have more gas wanting to expand to a larger volume causing higher cylinder pressures and more power. The side effect of more air in the cylinder is more available oxygen. Since there is more oxygen in the cyliner we can burn more fuel to make use of that coincidentally available extra oxygen.

4. But here's the thing about introducing extra oxygen as part of the fuel. It doesn't increase the volume of gas in the cylinder that can be expanded. Therefore it doesn't contribute to making more power. In fact, it seems that it consumes energy from the reaction and lower power output of the engine. If oxygenated fuels reduce NOx emissions by lowering combustion temperatures, then the extra oxygen is not contributing to moving the car and is actually working against us by lowering the power output of the engine.

 

Ethanol in gasoline is a pure political play for the farm states. It makes absolutely no sense. The ethanol requirement has created a temporary reduction in available gasoline supplies and has therefore resulted in higher prices. Someone was blaming the government for the high price of gasoline in another forum. I was defending the government as they don't really control the price, however, their requirement for ethanol has created a price hike and they should be held accountable. The federal government could eliminate the ethanol requirement immediately and that would result in lower prices.

 

If I understand correctly, the gov't has not REQUIRED ethanol, but they would not protect the oil companies from lawsuits in regards to MTBE, so the oil companies then made the choice to go ethanol rather than risk lawsuits in regards to the problems with MTBE.