Prius brake problem raises conundrum for entire industry, bad news for environmental advocates (NYT)

[concerned1]

http://www.nytimes.com/2010/02/04/business/global/04prius.html

Prius Brake Inquiry May Be Another Blow for Toyota
By HIROKO TABUCHI and KEITH BRADSHER

NAGOYA, Japan — The Prius, a centerpiece of Japan’s cutting-edge technology, fell victim to Toyota’s widening quality crisis on Wednesday after Japanese authorities told the automaker to investigate reports of faulty brakes on the gas-electric hybrid... Slow-moving brakes on the car may have led to a collision last July, just months after the third-generation Prius went on sale in Japan, the country’s Transport Ministry warned Wednesday. At least 77 more cases of possible brake malfunctions have been reported in Japan since the newest model went on sale in May. The company had not yet decided about a recall, but a spokeswoman said a defect with the brakes could not be ruled out... The Prius is one of the world’s best-known cars and the centerpiece of Toyota’s campaign to portray itself as more environmentally aware and progressive than its rivals. Toyota had promoted the cutting-edge design of the Prius brakes as a feature that gives the car a technological edge and better mileage...

Experts say a possible problem with the regenerative brakes in the Prius raises a conundrum not just for Toyota but for the entire industry. It is also bad news for environmental advocates who considered the technology one way to help improve fuel economy and reduce the contribution of automobiles to global warming.

Regenerative braking is simple in theory but complicated in practice. The energy of most cars’ momentum is wasted during braking, as brake pads exert friction against rotors on the wheels and heat up. The theory of regenerative braking is that the car’s momentum is partly used to recharge a car battery. This helps to slow the car while storing power that can be used to help the car regain speed later. John German, a semi-retired auto engineer and an expert on environmental engine technologies, said that adding regenerative braking improves a car’s gas mileage while driving in a congested city by at least 10 percent. Practically all hybrid cars have regenerative braking. “The greater benefits occur if there are frequent braking events, as you find in congested city driving,” said Danilo J. Santini, an urban systems engineer at Argonne National Laboratory in Argonne, Ill.

Some early hybrids, like the Honda Insight, added regenerative braking to conventional brake pads for extra force in slowing a car. But the Prius and other hybrids increasingly rely on complex electronics to combine the regenerative braking with brake pads, so that battery recharging absorbs as much energy as possible...

[gratuitous]

1. "Bad news for environmental advocates"?

Reach much, New York Times? Yeah, one automotive technology designed to cut carbon emissions and greenhouse gases doesn't hold up, so that's bad news for environmental advocates. Let's junk CAFE standards, catalytic converters, and all the rest of it. Makes perfect sense in Timesworld.

Ridiculous.

[fujiyama]

3. I didn't understand that part either

Kind of stupid. It's as though the Prius is the only fuel efficient car on the road.

While it's mileage may be higher than others, competitors offer plenty of choices now. Honda, GM, and Ford all have hybrids.

Besides, it being fuel efficient has nothing to do with the break failures. Regenerative breaking doesn't have to lead to not being able to stop. Hell, I hadn't heard of anything regarding previous generation Priuses either.

[mn9driver]

2. Not good if an electrical failure causes your brakes to quit.

This is a design issue. Regenerative brakes can be made "fail active", but Toyota's engineers evidently didn't do that for some reason.

[FarCenter]

4. Without mechanical drawings, circuit diagrams, and code listings, articles like this are useless

[AdHocSolver]

5. Tens of thousands of people are injured or die in car crashes each year. Ban all cars! nt