Prius topped off gas by the gas attendant...

NO...................

 

What's your point? My point is ... The metal part that might touch liquid gas does Not pump that gas back into the ground.

 

El - Could you please get me the brand name of the FDN with the accordion plastic boot? Thanks

Before discussing further, please read through one of the FDN patent which employs accordion plastic boot: Patente US5450884 - Multi-compartment spout for fuel dispensing nozzle - Patentes do Google. Please note that the attached pictures don't show the boot but in the description below does mention about it. (I prefer reading patents of some products because that the only way I can see the whole technical details behind.)


Here are a few things listed in the patent:

Multi-compartment spout for fuel dispensing nozzle
US 5450884 A

Resumo
A multi-compartment spout for a fuel dispensing nozzle includes a cylindrical, longitudinally extending outer wall, and at least one interior, longitudinally extending dividing wall. The dividing wall defines a fuel passageway within the spout which communicates with a fuel passageway in the body of the nozzle for dispensing fuel into the fuel tank of a vehicle, and a vapor recovery passageway within the spout which communicates with a vapor recovery passageway in the body of the nozzle for returning fuel vapor to an underground tank and thereby preventing the vapor from escaping into the atmosphere. In a preferred embodiment, the spout includes another interior longitudinally extending dividing wall which defines a shut-off passageway within the spout which communicates with a venturi-vacuum chamber in the nozzle for automatically shutting off the flow of fuel through the nozzle when the vehicle fuel tank is full. The shut-off passageway within the spout has a common interior, longitudinally extending dividing wall with the fuel passageway or the vapor recovery passageway. The spout is extruded of a lightweight metal and the body of the nozzle is molded of a composite resin.
......
(Please open the pictures in the patent above to see the typical cross section cuts of the FDN spout.)
.....
Fuel dispensing nozzles having vapor recovery capability take one of two known forms. U.S. Pat. RE No. 30,050 to Hansel and U.S. Pat. No. 5,174,346 to Healy describe vapor recovery nozzles which include a flexible accordion-shaped boot mounted to the egress end of the nozzle. The boot surrounds the spout and extends outwardly from the nozzle in the egress direction thereby defining a vapor recovery passageway in the space external of the spout and internal of the boot. The free end of the boot forms a seal against the opening of the fill pipe from the fuel tank. Pressure created by fuel rising in the tank displaces and forces fuel vapor to pass through the vapor recovery passageway in the spout and into a vapor recovery passageway in the nozzle. The fuel vapor is further driven from the vapor recovery passageway in the nozzle to a vapor recovery conduit within the fuel hose which is connected to the underground fuel tank. Vapor recovery nozzles of the flexible boot type are not particularly efficient and a substantial amount of vapor is allowed to escape into the atmosphere.

....

Anyway, I believe every FDN must have a vapor recovery passageway integrated into its spout. Without it, top off your gas tank would cause overfilling and flood. The rubber boot is only the additional device to capture fuel vapor. In Healy FDN, the boots are part of the nozzle mechanism to prevent spilling if you intend to squeeze the trigger without inserting the spout into the gas tank opening...

 

I'm not exactly sure what is being debated here but those accordion things on the nozzle just send vapor back, not overflowed gasoline because... well.. gravity. Also, even if it did there would be plenty of evidence of spilled gas around the inlet where it came out of the gas fill pipe and pooled in the large gap between metal nozzle and plastic vapor recovery spout...
Also the accordion thing has nothing to do with shutting off the gas when your tank is full. Plenty of pumps in certain locales don't have any vapor recovery on them and have been shutting off just fine for decades..
See

to find out how that works.

 

Your belief is wrong.

Only the ones with the accordion boot have vapor recovery.
You are confusing "automatic shutoff " with "vapor recovery".
Two entirely different things.

And it is possible to cause overfilling and a "flood".
It's not easy but it can be done.
And it has NOTHING to do with vapor recovery.

 

What's a gas attendant?

 

You are right!!! I was wrong when using the word "believe". I should have done a little research before writing it. Anyway, hope that the 2 EPA documents below will be the answer to whomever is still skeptical...

1991: Stage I & II Vapor Recovery Programs began. Stage II Vapor Recovery
-Stage I was about transferring of vapors from the underground or above ground storage tank back to the tanker truck's empty tank compartment while the tanker truck unloads gasoline product(s) into the storage tank(s).
-Stage II Vapor Recovery Systems collect gasoline vapors from vehicles' fuel tanks while customers dispense gasoline products into their vehicles at gasoline dispensing facilities. The Stage II system consists of special nozzles and coaxial hoses at each gasoline pump that captures vapors from the vehicle's fuel tank and routes them to the station's underground or aboveground storage tank(s) during the refueling process.

1993: A New Vapor Recovery Nozzle for Air Pollution Control
A New Vapor Recovery Nozzle for Air Pollution Control | Research Project Database | NCER | ORD | US EPA
....
Phase: II
Project Period: September 1, 1993 through November 1, 1994
.....
Description:
The vapor recovery nozzle is an air pollution control device which relates to Stage II emission control equipment designed to capture gasoline vapors during automobile refueling at service stations. The existing vapor recovery nozzles are difficult to handle, the bellows prone to cuts, and the vacuum assist pumps require frequent and costly maintenance. The primary objective of this project is to develop a new, more effective, low initial cost and low maintenance cost vapor recovery technology. This technology is based on a proprietary bellowless vapor recovery nozzle with an onboard vapor recovery pump, and aims at solving major problems inherent in previous designs.

("Bellows" in this document refers to the accordion plastic boots used in the FDNs to collect fuel vapor during fuel transferring from dispensers to vehicles.)

2012: Phase out Stage II Vapor Recovery Program. Stations/dispensers will no longer need to collect fuel vapor during fuel transferring from dispensers to vehicles. Charcoal canisters in everyone's vehicle will have to absorb fuel vapor during fuel transferring.

However, each state still has its own polution control requirements. The new kind of boot (shown in the picture posted by El Dobro in page 2) will still be in used because it will provide a tight seal during gas pumping. Gas stations will not give up on the FDNs with the integral vacuum line in the spouts because they generate extra income for the gas stations' owners when people top off their tanks. It's legal because there are signs every where tell you not to top off when pumping gas...

 

I haven't looked at my manual for my 2014 PIP, but I remember reading in the manual for my 2010 Prius IV that you should stop filling the tank on the first or second click at there is a risk of doing damaging to the vapor recovery system which could be costly to repair.

 

Good Kyle.
There may be some misunderstanding, however, about the 1993 "project".
I believe that it was a total failure......and no such device was ever created for use in the real world.
At least it never came into common use.

 

This is one of the typical fuel dispensing nozzles (FDNs) which have been in used since 1995:
https://www.google.com/patents/US5417259?dq=fuel+dispensing+nozzle&hl=en&sa=X&ei=EGdjU7WPJJeEoQSwYA&ved=0CGwQ6AEwCDgK


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
.....
A spout 20 is mounted on the outlet end 13 of the main body 11 and extends outwardly therefrom. Spout 20 has a fuel delivery passageway 21 extending longitudinally therethrough which is communicatively connected to the fuel passageway 14 in the main body 11. Spout 20 also includes a vapor passageway 22 therethrough which is communicatively connected to the vapor passageway 15 in the main body 11.
.....

 

By the time the FDN shutting off, fuel level in your car's gas tank is already way up high in the filler neck. Any additional fuel adding after that will be returned to the underground storage tank through the vapor passageway inside the FDN spout. This is one of the safety features being built into the FDNs to prevent pollution. Nobody tries to cheat you!

The conclusion is: No - Topping off your gas tanks doesn't damage the OVRS in your cars but your wallets...
(OVRS = Onboard Vapor Recovery System)

 

Disagree as I have seen it happen!!!!! Whatever you choose to believe go ahead and risk damage. Also if you search here on Prius chat you can find owners who reported having damaged their Prius by topping off.
All things mechanical fail at times, the risk is yours!!

I suppose you have never seen the gasoline flowing all over the ground because the pump handle shut off failed?

 

So if I tell you that the brake system in your car is to protect you from running into something and you tell me that I'm wrong because people get killed everyday because of the failure in their cars' brakes... Is that what you are trying to tell me?

The FDN shown in page 2 has a lot safety features built in but if the automatic shut off and gas stations vacuum system fail, your OVRS could be damaged because fuel will be foced to go into your car's charcoal canister...

 

Don't have something else productive to do, Kyle ??

I have been ALL over the country and don't remember EVER seeing a fuel nozzle like that.
I admit, however, that ai haven't been in California much and they might be in use there.

So, how about it folks.
Anyhbody ever seen a fuel delivery nozzle that had a vapor recover rib/holes down the back of the nozzle ??
Without that accordion boot, that is ??

 

Never in at least 20 states. I don't even remember seeing them in California back then.

 

oops...Double post thing again.

 

No I am just saying that you are wrong!!!! Out in left field actually!!! For me it is stupid and not worth the risk of significant cost to fix the potential damage.

 

yes in oregon the government feels it necessary to have professional gas pumper to keep people like me safe. if you are in oregon just go to costco the gas is usually the best price and they just fill to first click and you are on your way pronto.

 

you can punish clowns like that here in Hawaii by calling 911 ask for fire dept, tell them the truth and insist the haz-mat team should respond.. maybe the county might even send them a bill for $30,000 for the response. be a good citizen & all.