Fuel Bladder Necessary for PZEV Certification? Apparently Not.

[Patrick Wong]

Originally Posted by Rokeby

The car next to me in the parking garage today had a PZEV sticker on the driver's side rear window, just like my Prius...

So, there it is, the fuel tank bladder is not necessary to meet PZEV requirements.

Just why is it then that Prius owners are saddled with this millstone?
What is it really doing for us, and for the environment?

Well, there is a difference between a PZEV vehicle and an AT-PZEV vehicle: Partial zero-emissions vehicle - Wikipedia, the free encyclopedia

Prius falls into the latter category. Camry Hybrid also is AT-PZEV certified: Toyota Camry Performance & Specs

The fuel tank bladder is intended to reduce hydrocarbon emissions into the atmosphere. The good news is that the Camry Hybrid fuel tank does not have a bladder. However instead of a bladder, the fuel tank has an extra pump that is intended to help keep gasoline vapor out of the air - hence, it also contains a layer of complexity that regular vehicles do not have. Highlander Hybrid has a similar fuel system as Camry Hybrid, although HiHy is PZEV certified.

My guess is that 3G Prius will likely have a similar fuel system as CamHy and HiHy since the 2G fuel system is not as easy to use as we owners would like.

Why does Classic and 2G Prius have the bladder while other Toyota hybrids don't? Probably because the US Prius fuel system was designed back in the late 90s. Toyota had a chance to learn from that and designed an all-new HiHy fuel tank system first introduced in 2005.

[ranchogirl]

Originally Posted by ranchogirl

I saw a Ford Focus today with a FZEV sticker on the side window. I have a lot to learn about what this means, apparently.

Just educating myself...

2007 Ford Focus PZEV - Car News/Green Machines/Car Shopping/Hot Lists/Reviews/Car and Driver - Car And Driver

Carry on...

[Rokeby]

Having to put up with the vagaries of the fuel tank bladder irks me to no end.

Up until I discovered that other far less sophisticated cars than the Prius
have the PZEV rating, I accepted the quirkiness of the whole fuel
bladder/"guess gauge" thing as a necessary part of "doing the right thing"
vis-a-vis ecological responsibility. But now that I know that countless
models of Fords, Hondas, Subarus, Toyotas, and God only knows what else
have the same rating and no fuel tank bladders, I'm on a slow burn.

I really appreciate the info posters have provided. But something Patrick
Wong said just makes me steam:

"Why does Classic and 2G Prius have the bladder while other Toyota hybrids
don't? Probably because the US Prius fuel system was designed back in the
late 90s. Toyota had a chance to learn from that and designed an all-new
HiHy fuel tank system first introduced in 2005." [emphasis added]

What? Toyota had a better answer prior to 2005, and put it in the HiHy, and
not in its flagship hybrid the Prius?

Just how is that realization supposed to make me and all the other 2006,7,8
"Gen2.5" owners happy?

[bwilson4web]

My first computer used amplifiers, resistors, and capacitors. Next to it was a computer that used a TTY terminal with punched paper tape. Then came the 80-column cards and readers followed by all manner of dumb terminals or coax connected displays. Today, I use a laptop and program whatever and whenever including small computers the size of a cracker crumb.

Technology changes and sometimes we have to put up with systems that taught us "lessons learned" so the next versions are better than those before. Often the newer systems cost less and work better than the ones that came before. It is how the world of technology works.

So maybe in 2010 we'll see the end of the bladder tank or maybe not. Regardless, it is unlikely we'll see it in any new designs and we can be thankful for that.

Bob Wilson

[Rokeby]

Bob,

I'm in a peckish mood tonight, so I'm going to play devil's advocate. I mean
nothing personal here, it's more a rant aganist Mother Toyota.

Originally Posted by bwilson4web

... Technology changes and sometimes we have to put up with systems that
taught us "lessons learned" so the next versions are better than those
before. Often the newer systems cost less and work better than the ones
that came before. It is how the world of technology works.

It may be some element of perversity in my point of view tonight, but it
seems like what you've said supports my sense of simmering frustration.

It would appear that Toyota had the "newer system" in '05, but chose not to
implement it in the Prius in '06. Could it be that they were resting on their
corporate laurels, and in an market with no true competition, simply left
"good enough" alone? If so, there's no leadership there. Or could it be that
implementing a new system would have been seen as an acknowledgement
of the inherent weakness of the bladder and engendered backlash amongst
2003, 4, and 5 model buyers stuck holding the bag, as it were? Keeping the
fuel tank bladder was then purely a matter of "saving face."

I wonder if there are any other surprises in the way of technological
advances withheld.

[miscrms]

If the bladder is the price to pay for all the other pluses in a Prius, I'd say we're still way ahead of the game. I honestly can't fathom why people get so worked up about it.

Every vehicle on the road is a compromise of technology, performance, and cost amongst other things. When the Prius system was developed it was already on the cutting edge of emissions technology. New technology costs money, making it tough to roll it out in a moderately priced vehicle. You'll notice, for example, that all of the Lexus hybrids and Camry Hybrid also have lower tailpipe emissions than the Prius. I think this is simply a combination of newer design, and the ability to pack more high tech goodies into a vehicle at a higher price point. The '06 "redesign" of the Prius was exceedingly minor. Aside from the MFD, taillights, the touring suspension, and a few other cosmetic things they are basically the same car. Making any more systematic changes would have required a huge amount of testing and certifications that would have greatly increased the cost of the changes. My guess is that at that time, based on the number of sales to that point Toyota would have been doing well to have broken even on their huge initial investment in the Prius and was not up for pouring a bunch more money into it until it had proven itself financially successful. I can't really blame them for that. They had already been waiting about 8 years to see their investment and patience pay off. Now that the Prius is a clear success and we know a major revision is coming next year I would fully expect Toyota has put everything they've learned in the last 10 years into it, assuming it fits within the Prius' price point.

Rob

[Patrick Wong]

Originally Posted by Rokeby

...What? Toyota had a better answer prior to 2005, and put it in the HiHy, and not in its flagship hybrid the Prius?

Just how is that realization supposed to make me and all the other 2006,7,8 "Gen2.5" owners happy?

Most car companies including Toyota will produce a given model for a six-year period (i.e., 2G Prius will be produced from the 2004 to 2009 model years). During that period, it would be unusual to see substantial engineering changes made to the model, especially when annual sales in the US are only 150K-175K units per year. This allows parts suppliers to amortize tooling over a longer production run and reduces parts costs, field support costs, etc.

You may or may not be happy with the result. However, it is what it is. Hopefully 3G will have a fuel system similar to CamHy and HiHy.

[john1701a]

Originally Posted by Patrick Wong

Most car companies including Toyota will produce a given model for a six-year period...

Yup, mid-cycle updates are definitely not the norm. That's why the introductions of the Highlander and Camry hybrids were so exciting. They're sneak previews of what continuous engineering improvements bring. Not all changes trickle down to the lowest priced offerings. But in our case, expecting things like the much smaller inverter is quite realistic.

.

[Rokeby]

Well, it's a new day, I got a good night's sleep and have had a cup of strong
coffee. I don't feel so put upon by the seeming arbitrariness of the the fuel
system. I'd like to thank the responders for the reasonableness of their
posts.

I can now look at the fuel system from a much broader perspective including
production cycles, vehicle pricing, and Toyota's recovering its long term
investment in bringing the Prius to market.

In this quieter, more sanguine mindset, I was able to go back and look at the
fuel system diagrams, and see them afresh. It it remarkable how the
system accommodates the many possibilities for things going awry in the
real world.

Nonetheless, at times it is hard not to think that the fuel system was
designed using a map of the New York subway system as a template.

http://www.autoshop101.com/forms/Hybrid13.pdf

[Patrick Wong]

Originally Posted by Rokeby

...Nonetheless, at times it is hard not to think that the fuel system was designed using a map of the New York subway system as a template.

My guess is that the US Classic and 2G fuel system was designed by a bunch of newly-minted engineers who graduated from the Rube Goldberg school of engineering!
Rube Goldberg machine - Wikipedia, the free encyclopedia

The CamHy and HiHy fuel systems are more complex than normal; however I haven't seen any complaint about owners having trouble refueling or a pump failure, so far.