im still laughing about this theory of yours as i am typing this because first if you wanted to make this work you would need a tank then hoses, couplings a solenoid and alot of time and effort would be wasted to have something that would be very unique but it would serve absolutely no purpose. you have to ask yourself why your engine would catch on fire. IT WOULDN'T, gasoline can catch on fire but if your so worried about that then get a automotive fire extinguisher
here is a chart for the temperature of gasoline at its ignition points and it spontaneous combustion levels
http://hypertextbook.com/facts/2003/...istopher.shtml im not shooting your idea down but there are easier ways to do things, for example whenever i go to car shows i take LOTS of pictures but i only had a 128mb card for my camera.The logical thing to go was to get a bigger card for my camera but instead i got build a computer into my car that cost 50 times more then the cost of a 1 gig flash card.
my point is simplicity is the best thing when engineering something