Originally Posted By: mightymousetech
Originally Posted By: Coprolite
I should probably read up on modern fuel tanks, but I haven't had to worry about any of those. I bet the mechanism to keep air out would be quite interesting...
When there isn't fuel in the tank, what is there? I always thought it would be air. A quick google shows that not all cars have bladder type gas tanks, so how is air prevented in the tank?
Above the fuel will be fuel vapours. Modern tanks are very well sealed from the outside, even a leak the size of a pin hole will trigger the engine light, and when driven, the tank is kept in a vacuum state. The higher volatile elements in the fuel will evaporate to fill the void. When you fill up, there is a small amount of air that enters the tank, but that is quickly pushed through the ORVR valve into the charcoal canister as the fuel level rises.
There is air...it just happens to have vapors exceeding the flashable ratio. This is just like exhaling oxygen. Below a certain percentage, the body can't extract any more so it might as well not be there but one can't say that it isn't there.
So, did you store it with a full tank? If so, why?
With my small engine fuels always stabilized, I don't pay attention to fuel level anymore. I also don't have the cars that I would worry about in storage. I do try to rotate vehicles to keep the fuel relatively fresh though.
I simply refer to gaseous state things as air...this reduces confusion with gasoline, but leads people to misunderstand what I was talking about as we can see on this thread...