Shell Oil is hyping their gasoline as being nitrogen enriched. What is supposed to be good about that?

If I remember correctly from my chemistry classes, you get energy from the combustion of carbon and hydrogen to propel your car. The combination of nitrogen and oxygen is endothermic or neutral as far as energy is concerned. Additionally, it forms one of the pollutants that catalytic converts were designed to remove.

To me, it is like using ethanol, you can't burn the oxygen in the alcohol, so you get less miles per gallon.

On top of that, your car gets plenty of nitrogen, it is about 70% of the air that comes in through the intake.

Can someone explain why nitrogen itself in fuel is a good thing? I can understand nitrous oxide, but I dont think Shell is peddling racing fuel.

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1983 300SD "Guderian"
1987 MR2
2015 Camry
2015 Chevy Spark
2006 Hyundai Tucson