What is the purpose of fuels listed as "oxygenated"?

The purpose of oxygenated fuels is to add extra oxygen molecules to the combustion process. These fuels contain additional oxygen-bearing compounds that enhance the combustion efficiency. By increasing the availability of oxygen, they help improve the completeness of the combustion reaction. This can lead to more efficient fuel use and reduced emissions of carbon monoxide and unburned hydrocarbons, resulting in a cleaner burning process.

When fuels have a higher oxygen content, they rely less on atmospheric oxygen alone, allowing for more complete combustion even in conditions where mixing might be less than ideal. This characteristic is particularly beneficial for reducing pollution, as it aids in achieving more thorough fuel combustion and minimizes harmful byproducts in the exhaust.

The other options do not accurately reflect the primary function of oxygenated fuels. Increasing the amount of air needed for combustion or reducing the amount of air does not align with the role of these fuels, as they work to optimize combustion rather than change air requirements. While helping keep the oil cleaner is important, it is not the main purpose of oxygenated fuels.