There is persistent myth that "premium" high grade gasoline somehow benefits your 93 ford taurus or other cars designed to run on low and mid grade gas.
I suggest assigning a certain shape inlet on each car the corresponds to the appropriate grade. That way you would instantly know what grade fit your car without having to do RON/PON calculations etc.
Now most modern gas stations only have one nozzle that administers different gas, but the button to select gas could be in the shape of your inlet.
Futhermore diesel fuel should retain the standard round nozzle that wouldn't fit (or just barely fit) inside the now square triangle and star shaped holes. That way it would prevent idiots from putting diesel in their gas engine.-- metarinka, Jan 27 2011 I don't really undersand this idea...You want to change the shape of the buttons? What if we could just put some sort of number like digits on there? So that when people pulled up they could know that their specific car corresponds to a particular hieroglyph, then simply select that number? And furthermore, what have you got against stupid people anyways?-- KAGE, Jan 27 2011 [-] pandering to idiots.-- 8th of 7, Jan 27 2011 Most cars will run on either grade. (except for diesels, which everyone knows.) This would especially be troublesome on a dark, stormy night when your *high grade* auto was out of gas and the nozzle won't fit!-- xandram, Jan 27 2011 Since the main differences between these fuels is the amount of anti-knock agents added to the fuel, there is no harm to done a vehicle by putting in overly-high octane rated fuel. That said, the reverse is not true: if your car has a high compression ratio, it will be damaged by the use of fuel with an octane rating too low.
Therefore, it would seem sensible to have a slight variation on this: to alter the size of the fuel filler rather than the shape. The lower the car's necessary fuel grade, the larger the hole; this way economy cars can put in any fuel while perfomance cars can only put in the proper higher grades.
I'd certainly bun it this way since it would prevent people ruining their engines by using Asda's own brand reformed paint thinners because it's cheap and says 'petrol' on the label. (I don't actually know about Asda, it's just an example). I think a bun for the idea though [+].-- TomP, Jan 27 2011 Clarification.
This is an idiot proofing scheme. A lot of folks do think adding "premium" gasoline will increase performance. There's anecodotal evidence that old engines with carbon build up will have an increased compression ratio + higher running temp that will induce knock
It was to give someone an easy clue as to what grade they use as a lot of vehicle only list it in the booklet OR list a PON or RON number instead of both.
They would still fit inside it would just be awkward. This was really for the absent minded people who put diesel in their car accidentally.-- metarinka, Jan 27 2011 I get a real kick out of watching construction of gas stations.
They'll install 2 underground storage tanks - one diesel, one gasoline.
Then they sell diesel and 3 grades of gas...-- lurch, Jan 27 2011 random, halfbakery