Jul 7, 2009

Prius fuel-bladder idea runs out of gas

The 2010 Toyota Prius has a bigger engine, better fuel economy and solar-powered cabin cooling.

What it doesn't have is the innovative "fuel bladder" that has served as the Prius' gas tank since the Japanese-built hybrid landed on these shores almost nine years ago.

Toyota ditched the environmentally friendly bladder in part because some Prius owners complained that the collapsible container held much less fuel than the 11.9 gallons listed in the owner's manual, taking a big bite out of the car's range. Other owners said the flexible tank's fuel gauge tended to signal prematurely that the tank was close to empty.

So Gen III of the groundbreaking gas/electric will use a rigid tank made of a lightweight resin.

"The chief reason was because one of the sore points with the current-generation Prius" dealt with the fuel tank and gauge, Toyota spokesman Bill Kwong said.

The change is coming too late for Darlene Sharar, an engineering technician in rural Washington who often drives in areas where gas stations are few and far between.

"In any other car I've owned, I know a tank of gas will get me X number of miles," said Sharar, adding that she often could pump no more than seven gallons of gas into her 2008 Prius, even when the fuel gauge was flashing "empty."

"Instead of a range of 500 miles, I've got a range of 300 miles," she said. The previous Prius gets 46 miles per gallon in combined city-highway driving, according to government figures. The 2010 comes in at 49 m.p.g. combined.

Attempts to get Toyota to resolve the issue were unsuccessful, she said. In an e-mail to Sharar, a Toyota customer service representative said the issue involved "the design of the fuel tank and there is no repair available to change the design." Sharar traded in the Prius for a 2009 Toyota Camry.

The automaker blames the fuel storage problem in part on temperature changes. The Prius owner's manual notes that the capacity of the fuel bladder drops by about 1.3 gallons at 14 degrees Fahrenheit.

As for the gauge, maintenance manuals say recalibrating it can sometimes solve the problem.

Owners with a fuel-bladder problem usually complain that the tank won't take more than 9 1/2 or 10 gallons of gasoline, Kwong said, adding he had never heard of the bladder taking only seven gallons.

Bladders help prevent fuel vapor from building up in the tank, thereby reducing hydrocarbon emissions. The Prius' new fuel tank will use an improved vapor-recovery system that will allow the car to retain its low-emission rating in California.

Courtesy of chicagotribune.com

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