I want to see a picture of the gas tank with the bladder in the middle. It would be interesting to see. Would it look like a ice chest with a type of sponge layer that can contract like the bladder?
Haha, sorry for the delay! Anyway, here it is - the comparison between the 03 prius gas tank (bottom) and the 04 tank. Enjoy! -m.
This clearly shows that carefully topping off the tank fills up the plumbing and the charcoal canister. This increases evaporative emission of unused fuel. Those who do this go farther to their next fillup at the cost of decreased fuel economy and increased air pollution. Thanks a lot, guys.
Some gas tank! If the inverter assembly (front thermal tank) costs $6400, imagine the cost of the gas tank assembly!
Once again, being the new guy here, What is the purpose of the tank liner anyway? Is it strictly to stop evaporative emissions? Makes me wonder if a fuel cell would have been more cost effective............
the tank liner is for protection. you must realize that the bladder is very fragile. it can be popped just like a balloon when full. The tank or liner is used to hold the bladder in place and keep it from getting punctured.
Yes - evap. emissions was the primary prupose. Because the bladder in theory collapses around the fuel, there is less open area for vapor to form. In practical experience, however, it seems that sometimes vapor can still become trapped, and possibly yield us less capacity than specs say we have. Also note that the filler neck enters from the side of the bladder rather from the top. This seems like we're filling from the side, which kinda seems "bottom up" rather than "top down" after you get 50-60% full. It would seem to me that could cause enough back pressure to cause some nozzles to click off prematurely. In addition to the bladder, there's the "side" tank where the fuel float, and pump pickup live. There are also one or more lines from the side tank and/or bladder for vapor purge. This purge is said to occur at startup, and may be responsible for some surging we experience shortly after startup (especially if you get on the accelerator, and then let off suddenly - the engine keeps on revving under power for up to 1 second after). hope this helps, -Rick
Hmmm. I'm waiting for a 2005 (I just got on the dealers list 051204). I guess it just seems odd that a fragile bladder would be used when a fuel cell can do the same thing with evap emissions and would be infinitely stronger in an impact. By the way, I crawled around in an Escape Hybrid yesterday and it seems like Ford may have done a good thing with it. I was surprised that the "Hybrid Appearance Package" isn't standard. Seems they would want people to instantly recognize the difference. I know lots of people hate SUVs but I know several people that actually need a vehicle that large so anything that can increase the mileage is a fine by me. I took a bunch of photos of it and am presently #1 in Portland to get one.
well despite the appearance of the drawing, i would expect that the bladder is being filled from the corner at the top which would allow filling of the bladder completely. I think the differences in the amount that can be put into the bladder has more to do with the amount of gas left in the bladder not being measured accurately.
The bladder doesn't bother me. I think that I would rather have it than not, only knowing that it is for the good of the air.
Ummm, following the path of gasoline down the pipe to the charcoal canister, I see two paths it can follow. One to the filter, one back to the tank. It has been mentioned before that fouling the filter will raise a Check Engine warning, so since I never see one, I believe the path back to the tank is being followed in my car...
mikepaul: i think you mean that the gas is going back to the filter. if the gas was going to the tank, it will eventually be vented to the atmosphere.
I think part of the problem of filling up fast and inconsistent fills has to do with the check valve that vents the outer portion of the tank/bladder area. As the bladder drains the area around it and the tank fills with air ( not contaminated with hydrocarbons) and when we fill up this air is displaced and there is an elaborate system to detect if the bladder is leaking and as it has to vent to the canister as well, filling at a reduced speed helps to displace the air. The sub tank contains the fuel pump also and the the fuel pressure regulator so that a return line from the engine compartment isn't required as it contributes to the formation of vapour that has to be released, the woosh you hear when you remove the cas cap on a conventional car. hope this helps.
