|
when your engine is cold not all of your fuel is turning in to vapor, so it's not all burning, but once your engine is warmed up all the fuel is burning the fuel then also has a cooling affect in the engine as it evaporates so it can be burnt, and the air is getting hot as the fuel burns as well making it less stable so any left over oxygen is going to look for something to bond to so it can oxidize it (burn it), so it will start to bond with the nitrogen in the air creating NOx and getting even hotter and given the chance it will bod with the metal of the engine, burning holes and bending valves.
|