Is stale gas a problem?

Isn't the fuel tank sealed and pressurized? There should be minimal breathing going on, and any that happens would be through a charcoal filter system.

 

STA-BIL is a wonderful product...and hurts nothing.

 

This isn't something that demands second-guessing.

Both of you are thinking of old-style unsealed tanks, before evaporative emission controls were mandated. The Prime's tank is quite well sealed.

Winnipeg doesn't get the same type of evacuation-required storms as Florida.

And considering his past fleet (he has been here longer than you and me combined), and the fact that his Prime (only 25-ish miles of EV range) is still on the original tank of fuel after 18 months, I somehow suspect that either this car isn't his only source of transportation, or he is very unlikely to suddenly need greater range from it. He is very clearly using this as a short-range BEV, not as a long range gasser (or diesel-er), so shouldn't be beaten up by folks stuck on old gasser rules.

 

No, I'm going to call it FUEL economy as in " Fossil Fuel Economy". I think we can default to the concept that people understand with a Hybrid we have more than one source of energy being utilized.

You're right that the cost direct and indirect of the electricity needs to be factored in, but I'll stand by my opinion, which is that the Gasoline usage...or lack of usage is very impressive.

 

This is NOT meant to be an insult or to start a flame war but.............

Sometimes when a hurricane is coming, the stations have LONG lines and actually run OUT of gas well before the storm hits.
Living where you do, you likely never experienced that.

And I am glad that you never have been so filled with grief that you forget where you are GOING, much less not paying attention to warnings on the dash.

Like I said, what you are doing makes you happy so that is the right thing for YOU to do.
Might not be right for everybody though.
Same for what I have decided to do.

To each his own.

 

Well it can't be totally sealed or the fuel pump couldn't suck the gas out.
And if the pressure inside gets too high due to heat, it must vent a little too.

 

I agree. Unless you put in way MORE than the recommended amount.
Which can happen if you just buy a bottle and blindly dump it ALL into the tank.

 

You must have forgotten the past descriptions about how the Prime pressurizes the tank as part of its evaporative control system's leak detection.

And also forgotten the purpose of the charcoal canisters in absorbing HC vapors from whatever pressure must be vented.

So I suspect that you have also forgotten the previously posted calculation about just how much (it isn't much) water vapor can possibly be included in the air intentionally pumped in to keep the tank pressurized as fuel is sucked out.

 

If you are concerned about stale fuel, there is a product called Sta-Bil fuel stabilizer. You can buy it at the auto parts store.

 

When the car is running the tank is generally at a lower than ambient pressure.
Powered down it has to breath through the evaporative (charcoal) system. But does charcoal filter out incoming moisture when the temp and pressure changes make a big difference in the air pressure in the tank?
Think your red plastic gas cans for lawn equipment. Those are truly sealed and bulge and contract a lot with temp and pressure changes.
The big gas tanks in cars can not be totally sealed.

Either way, live with it low on gas or full of gas.
Suffer the consequences either way....

 

Thus the E0* solution....


Rob43


* Is stale gas a problem? | PriusChat

 

Are you referring to the Prime, for which we hear otherwise? Or just to older car models?

 

Can't you find something useful to do with your time on instead of making useless and snide remarks ?

I was simply pointing out that the system is NOT completely sealed......which it is not.

 

I very well understand that my pointing out your repeated errors could be useless to you. That doesn't make them useless to others.

I'll quit correcting you when you quit making and repeating these erroneous assertions.

 

I hope you are enjoying yourself.
Saying something a slightly different way that YOU would say it does not necessarily qualify as "erroneous".

 

Boys, boys, let's talk about the evaporative emissions system on the prime, and not snidely whiplash subjects...

Is it different from the normal prius?
Is there a powered air pressure pump to keep the tank at a set positive pressure above ambient?
(how else can it get a positive pressure in the tank? Answer: through heat rise or ambient pressure drop.)
(one superior PHEV had this system)...

Either way the difference can only be so much. The tank has to 'breathe' to maintain whatever positive or negative pressure difference.
It does exhale through a charcoal canister which get's purge during engine running. All modern cars have this system.

And here's a test for the 'keep it empty, too much weight in unused fuel' proponents:
Carry around ~60 lbs (?) of junk in the trunk for a week and see IF you can measure any difference at all in your electron usage, or for that matter gas usage.

 

At the risk of drawing even more fire from "fuzzy":
Carrying extra weight requires extra fuel ONLY during acceleration.
The extra required to KEEP that extra mass moving is miniscule.
On a vehicle with regenerative braking, you should recover MORE energy because of the extra weight.

So......a person who already is careful about his accelerating and braking techniques likely will have to add a LOT of weight before any difference will be noticed.

 

Re: Prius Prime fuel tank pressurization

From Dear Moderator of PriusChat, and one regular member:

Is fuel stabilizer necessary? | PriusChat
"I believe the Prime (and Gen 4) gas tank is pressurized. That should help keep the fuel fresher for longer, right?"

Ethanol Restrictions Lifted | Page 2 | PriusChat
"Plus, with plug-ins like the Prime, PiP, Volt, etc., the fuel tanks are pressurized. That's why you have to get an OK to fill them."

From Honda Corporate, on YouTube, how to get that OK to fill the tank:
Honda Insight's Pressurized Fuel Tank

From Toyota Corporate, Prime Owner's Manual, how to release the tank pressure before filling the tank:

 

Here is another Google search result on this topic, hopefully with enough details to quell uninformed speculations and assertions:

Autoblog: How desiging the Chevy Volt's sealed gas tank brought automakers, CARB together

"... but now we've got the scoop on the gas tank used to keep liquid fuel in the Volt from evaporating or going stale for up to a year.

Back in 2009, we learned that the Volt can move without gas in the tank, but that's only part of the problem that GM engineers had to solve. They also needed to figure out how to keep fuel from simply evaporating away. Standard vehicles use charcoal canisters to trap the gas, and then return it to the tank once the engine starts running. In the Volt, though, the engine could potentially remain off for a very long time even under daily use – up to six weeks, before the Volt's "maintenance mode" automatically kicks in. That's why a special sealed steel tank was developed. ...

Recently, we spoke with Jon Stec, fuel system integration engineer for the Volt, about the sealed tanks came to be. ... GM began talking with other OEMs and CARB to figure out how to design a fuel system that would work with a plug-in vehicle, because a conventional system wouldn't work. The most important thing to figure out was how to handle evaporative emissions and prevent hydrocarbons from getting into the air.

Typically, in a standard vehicle, the fuel system captures errant hydrocarbons in a canister and, when the engine runs, it purges that canister. "This time," Stec said, "we don't have the engine running all the time, so what do you do? Do you put a gargantuan canister down there and hope that whatever hydrocarbons you're going to develop – typically because of temperature changes and fuel fill – will be caught? That's not very feasible."

GM knew other technologies were possible. On earlier Prius models, for example, Toyota tried a bladder tank, where there was an outer shell with a flexible shell on the inside that would shrink to try an reduce the space where vapors could form and deal with emissions this way. "That didn't work so well for them," Stec said.

This time around, the OEMs involved collectively decided to make a pressurized vessel, to seal it and then to give the the powertrain the controllers to open and close the system. The reason that GM worked with others to develop this system was because having each manufacturer come forward with its own proposal and hoping that the regulations concerning the tank emissions were flexible enough to allow for the different solutions seemed unlikely. "It had to be an agreement between all the OEMs, and it was resolved three or four years ago that we do this process (use a sealed system)," Stec said. "All the OEMs, as far as I know, are going to pursue this technology."

Of course, if your fuel tank can't be sealed all the time. Since the Volt uses gas, drivers were going to have to open it up at some point to refuel it, so "we had to develop a whole new control process to unseal the tank without getting any hydrocarbons in the atmosphere and allow the customer to refuel the tank," Stec said. ... "

This article ends with a copy of a GM Press Release:

"Special Gas Tank Caters to All-Electric Chevy Volt Drivers
Pressure-Sealed steel fuel tank contains gasoline vapors from sporadic engine use
..."

 

Which Google search is it that will show us how to curtail your spiteful and unnecessary rants ??