Turning off your Prius while refeuling?

having the engine running is only part of the risk. with the Prius, if left on, is energized which could create a spark that could ignite fumes. granted, the odds of that happening in an open environment is infinitesimially small.

if that is an acceptable level of risk for you, go for it. keep in mind, that other occupants of the gas station you are at my have another opinion.

when i was a kid, it was very common to see people smoking a cigarette while refueling...still see it once in a blue moon. that is not illegal, though i find it a bit hard to believe.

 

your turn a car off when you refuel it because of the chance of a spark from anything...its why you also ground yourself (or should) before you touch anything. Notice the metallic strips F1 cars run over, those ground the car also. Now consider adding a serious amount of voltage amperage and electrical parts that the hybrid portion of your vehicles drivetrain consists of...yea shut it off all you would be doing is draining the battery anywways

 

If i remember right, myth busters tackled some of these myths... they found that cell phones and other small electronics wouldn't run the risk of blowing up at a gas station, i believe they also proved that smoking was ok too. it would be interesting to have them "test" the "myth" that a hybrid car can be fueled while turned on.

 

<div class='quotetop'>QUOTE(eagle33199 @ Aug 9 2006, 02:25 PM) [snapback]300329[/snapback]</div>

The fumes are the most dangerous part of fueling. That is what can ignite and blow you sky high. Smoking while fueling isn't dangerous? I suppose not as long as there are no fumes and the cigarette isn't lit... One stuff breeze and a spark touches some gas and you are a goner. Sorry to disagree and I admint I am a guy who at 20 below with a cold car will let it idle while I fill up, but as a general rule of thumb anything that has a spark or can create a spark increases the level of risk. Static shock can produce enough electricity to create an explosion. I have seen some crazy stuff in my life, especially back when I worked heavy construction, and I cannot imagine that anyone would smoke while fueling.

 

<div class='quotetop'>QUOTE(eagle33199 @ Aug 9 2006, 01:25 PM) [snapback]300329[/snapback]</div>

Myth vs. Reality -- an interesting question in this case. One can certainly debate the cause factors, but I'm sure that anyone from this unfortunate family would recommend that you do everything you possibly can to reduce the chances of a mishap (edit -- apologies, you have to scroll down to the story). By the way, the incident described in the linked story happened at the station where I buy gas about 3/4th of the time. Scary stuff, at least to me.

 

I remember that episode of Mythbusters.

If people don't know how the show works I'll quickly summerize.

They will test a myth like the cell phone exploding while getting gas or the bullet that blows up the SCUBA tank in the mouth of Jaws. Then if the myth fails they will go REALLY extream and see what conditions are neccissary to prove the outcome of the myth.

For the cell phone and the cigerette they simulated gas pumping with a lit cigerette. IIRC It wasn't until they airated the gas AND used a LIT match. It didn't work with either a cig or a cell phone. They tried hard...so use your own judgement, but they needed VERY extream conditions to get the gas to ignite.

 

I witnessed a very dangerous joke when I was a teenager. A construction worker put the oxygen bottle up to a cigarette before handing it to a co-worker. Basically the jokster had laced the cig with oxygen... When the recipient lit the cigatette it burned completely to the filter and he spit it out of his mouth just in time to avoid injury. It was like something you would see on an old disney cartoon.

I have seen puddles of gas ignite from a dropped cigarette. The fumes are far more flammable.

I realize the odds are small of having a problem, but it is better to be safe than sorry in my opinion. The cell phone thing is pretty far fetched, but anybody who has shuffled their feet across a carpet and then touched someone to shock them should be able to comprehend the possibility of a problem when dealing with flammable products.

 

Ok, this begs another related question. I've always been under the impression that gas may burn, but fumes explode. I believe the fumes have to be contained for a true explosion (bomb-like) to occur; I've heard of people who refuse to let their tanks go more than half empty because the closer you run it to empty, the more empty space there is for the fumes to accumulate=higher concentration of fumes=bigger explosion. This was aroud the time Pinto's were exploding when rear-ended. Seemed like logical advice.

The question: Since the Prius uses a bladder-type fuel tank, doesn't this greatly reduce the build-up of fumes (and thus the lower emission leakage)? I still advocate turning the car off while refueling, btw.

 

Wouldn't the bladder increase % of fume in the tank? Since the fumes form in the tank can not escape.

 

Myth busters also did a show where they shot a gas tank to try to make it explode (like they do in the movies). after much effort, they could never get the tank to explode or even catch on fire. i would think this would indicate that the gas tanks are fairly safe. now, the difference between this and being rear ended, i think, is the possibility of having loose electrical wires flying around causing sparks.

on another episode (don't remember what they were testing), they found that they had too high of a concentration of cas in their constructed box to explode - there wasn't enough oxygen to feed the fire.


Oh, and the idea of the bladder is that the gas stays in it, never leaking out into the tank where the fumes would gather. this would seem to indicate that there would be less fumes than in normal cars.

 

<div class='quotetop'>QUOTE(ZenCruiser @ Aug 9 2006, 01:43 PM) [snapback]300390[/snapback]</div>

I think the flash point of a liquid is the temperature it must reach to give off enough fumes to burn. Ignition temperature is the temperature required to actually ignite it.

Gasoline has a flash point of -45 degrees C, diesel is +62; there ignition temperatures are 246 degrees C and 210 degrees C respectively.

Reference: http://en.wikipedia.org/wiki/Flash_point

The gasoline should not ignite inside the bladder or a normal gas tank for that matter because the fumes are to rich, i. e. not enough oxygen. The problem is the fumes from the nozzle while you put it in.

 

I ALWAYS turn off any car while fueling it. I will occasionally even turn off my cell phone while fueling, it ALWAYS stays in the car during the process. And just in case someone needs a good reason to do it, this happened a few blocks from where I work.

Static ignites gas vapors at pump

 

<div class='quotetop'>QUOTE(jtullos @ Aug 9 2006, 05:02 PM) [snapback]300402[/snapback]</div>

I am not saying you shouldn't turn the car off, but this incident has nothing to do with the engine being on. It was the static that caused the gas to ignite.

 

Opening the gas cap with the car running can lead to a Check Engine warning light! <_<

 

In regards to the follow up question... I keep the fuel tank full because the fule pump is cooled by the fuel and will heat up in an nearly empty tank which can greatly shorten its liefe expectancy. In a prius especially, a fuel pump replacement is a very large expense.

 

the mythbusters attempts were all extreme. the only way they could get gas to explode was to enclose an area in plexiglass, build up fumes then use a static electricity generator that shot of 12 inch sparks.


but, i also saw on the news a guy in Bellevue filling up his vintage 1950's Jaguar. he was smoking, the gasoline caught on fire and SLOWLY englufed his car in flames. facts are, explosions are rare, fires are not. try to extinguish a gasoline fire after it has started. you dont have a lot of time

 

<div class='quotetop'>QUOTE(eagle33199 @ Aug 9 2006, 01:25 PM) [snapback]300329[/snapback]</div>

A friend of mine had a metal gas can in the bed of his pickup truck, and was refueling it when it sparked and caught on fire. I actually witnessed it.