I still find Shell's claim to be misleading. I use Shell gasoline exclusively, so I am not trying to slam the quality of their fuel. Nitrogen may be one component of a new cleaning system that they have developed, but I doubt that it has any cleaning ability all by itself. Think about it:
Nitrogen (N2) is a colorless, odorless and tasteless gas that makes up 78.09% (by volume) of the air we breathe. It is nonflammable and it will not support combustion. It is colorless, odorless and tasteless.
Nitrogen gas is slightly lighter than air and slightly soluble in water. It is commonly thought of and used as an inert gas; but it is not truly inert. It forms nitric oxide and nitrogen dioxide with oxygen, ammonia with hydrogen, and nitrogen sulfide with sulfur. Nitrogen compounds are formed naturally through biological activity. Compounds are also formed at high temperature or at moderate temperature with the aid of catalysts. At high temperatures, nitrogen will combine with active metals, such as lithium, magnesium and titanium to form nitrides. Nitrogen is necessary for various biological processes, and is used as a fertilizer, usually in the form of ammonia or ammonia-based compounds. Compounds formed with halogens and certain organic compounds can be explosive.