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The 2000 Volkswagen Lupo used start-stop to achieve a fuel economy of 75 mpg in Europe on a diesel engine. Manufacturers haven't brought the tech to non-hybrids in the U.S., due to flaws in the EPA's fuel economy testing.  (Source: Cars Plus Plus)
EPA is finally considering looking at the real value of stop start

Fuel economy ratings are supposed to provide an estimate of the vehicles' real-world performance, helping customers determine how efficient the vehicle is.  Unfortunately, the ratings are only as good as the tests that determine them, and in the U.S. Environmental Protection Agency's case, those tests aren't very good.

One significant oversight is stop start technology.  Overseas stop-start technology is featured on a host of models, including the Audi A3 TDI, BMW 1-Series, BMW 3-Series, Mazda 2, Mini Cooper, Toyota Yaris.  The technology is somewhat expensive -- it's about $500 extra to install -- however, it's more than worth it, providing fuel economy gains of around 7 percent.

The EPA's flawed test cycle, though, currently only includes one stop so the tech only earns automakers a 0.1 or 0.2 mpg increase in the official EPA mileage estimates, despite much larger real world gains.  Without the extra rating to justify the extra costs, manufacturers simply haven't been importing the tech on U.S. models. 

Currently, the only vehicles to feature the tech are hybrids such as the Toyota Prius, Honda Insight, Chevrolet Malibu Hybrid and BMW ActiveHybrid X6, as their electric systems allow the tech to be implemented at a much lower costs.  The net result is that at the end of the day, the U.S. is trailing the rest of the world in fuel economy.

Still the allure of models like the Volkswagen Lupo, which received an estimated 75 mpg, keep customers demanding that the EPA reconsider stop-start.  Robert Davis, Mazda's top product-development executive in North America, comments, "In Japan, we're seeing anywhere from 7 to 9 percent fuel economy gains from it. That's a jump from 33 to 37 miles per gallon in a metro environment."

Audi of America spokesman Christian Bokich complains, "We did not realize any savings in U.S. EPA estimates based on required testing cycles."

The EPA may finally be coming around and may try to fix its flawed test procedure.  It's taking public comment on stop-start technologies, currently, and will look to announce new procedures in April.  Those procedures could finally include a test with more stops.  Mazda is urging automakers to join together to lobby the EPA to give stop-start its just rewards.  While this is obviously a matter of personal interest to the company, it's also important industry wide, and to U.S. consumers.

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RE: How is $500 expensive?
By Solandri on 12/30/2009 1:54:29 PM , Rating: 3
MPG figures are misleading. Fuel consumption is actually the inverse of MPG, so MPG figures tend to de-emphasize how much extra fuel trucks and SUVs use, while exaggerating how much fuel hybrids save. (This is why most of the world uses liters per 100 km, not km per liter). The biggest savings actually comes from switching from the big SUVs to a moderately fuel-efficient sedan.

In other words, going from a 15 MPG SUV to a 30 MPG sedan cuts your fuel consumption in half. If you drive 30 miles per day, you'd go from using 2 gallons a day to 1 gallon a day - a savings of 1 gallon a day.

It is impossible to obtain the same fuel savings going from a sedan to any other vehicle, since reducing 1 gallon a day by 1 gallon a day leaves you with zero gallons a day consumed. A hybrid which manages 60 MPG will still use 0.5 gal a day, for a net savings of just 0.5 gallons. A 120 MPG vehicle would use 0.25 gal a day, for a net savings of just 0.75 gallons. Even a pure electric vehicle will have costs associated with electricity, and so will not save you as much as the 1 gallon a day you get by switching from an SUV to a sedan.


RE: How is $500 expensive?
By Lord 666 on 12/30/2009 3:30:53 PM , Rating: 2
Made my wife go from a 2005 CRV to 2006 Jetta TDI. Huge savings plus she feels safer in the car as it handles better and along with excellent side impact rating. She used to average 500 miles per week and the cost savings worked out to be about $100+ a month. Using $2.65 a gallon for diesel, that savings of $100 works out to be 37 gallons per month saved.

I'm now stuck with the truck driving it to and from mass transit.


"You can bet that Sony built a long-term business plan about being successful in Japan and that business plan is crumbling." -- Peter Moore, 24 hours before his Microsoft resignation











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