Went to a new owners clinic at the Toyota dealer this week and the service man told us about a bladder in the gas tank. Thought I had read on this forum that the 2010 Gen III Prius did NOT have a bladder in it. What is the correct information on this?
My 2010 has a bladder in it when it's moving. A few weeks ago it had 3 bladders in it when it was moving.
It makes you wonder what misinformation is given at the Toyota dealerships. Unless he was referring to the Gen II as a comparison and meant the Gen II having bladders
The bladder is used to minimize evaporative emissions. The operating principle is that it conforms to the liquid volume in the tank and minimizes the free volume that the vapor can occupy in the tank.
Apparently, Toyota engineers figured out how to meet the PZEV emission standard without using a bladder in the 2010. The bladder has been an issue for many owners because of the following reasons: 1. Fuel tank volume is variable depending upon temperature and also depending upon the shut off pressure of the pump. This led to people often running out of fuel because they assumed incorrectly that they should be able to travel the same distance on every tank. It also means that it is more difficult to track mpg based on miles driven / fuel added. 2. It is possible to damage the evaporative system by overfilling the tank. Once liquid fuel is trapped between the outer tank and inner bladder, the only way to fix is by replacing the system (tank, bladder, fuel pump) which is quite expensive. With those problems, you might be asking: Why would they choose to use a bladder in the first place? It was to meet the PZEV (partial zero emission vehicle) standard in California. See more: [ame=http://en.wikipedia.org/wiki/PZEV]Partial zero-emissions vehicle - Wikipedia, the free encyclopedia[/ame]
