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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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More than worth it?
By Shadowmaster625 on 12/31/2009 7:46:50 AM , Rating: 2
If your car gets 30 mpg, that costs about 10 cents a mile in the US. So after driving 50000 miles you've spent $5000. If you save 7 percent with stop-start, it means you've saved $350 after 50000 miles. Clearly, it is not worth the extra cost. Even if you did save money after 5 years of driving, you have to take into account your $500 five years ago is worth $650-$750 today. So the real inflation adjusted cost of stop-start is closer to $700 than $500. And you gotta pay tax and finance charges on that amount too. How does $800 sound? You'd have to drive over 100,000 miles in 5 years for this to pay for itself. But if you drove those kind of miles, they'd obviously be mostly highway, so your savings wouldnt be nearly 7 percent. Surprisingly, Americans are not universally stupid. There's a reason they dont bring this technology here; because its a ripoff. Gas needs to be well over $5 a gallon for it to make sense. And even then its only breakeven. Why pull forward your spending just to break even. Buying this technology, even if it does save a bit of money, leaves less money to spend elsewhere.

Not to mention you are increasing the wear on your starter motor, which could cause premature failure. So you may as well add an extra $20 to the price tag to cover the reduced average lifespan. Also, by stopping the motor you cycle the oil pump as well. And the timing belt. And many other systems that may or may not have been properly designed to constantly start and stop. Remember, it is the torque delta that causes most of the wear on belts, motors, and pumps. They all last much longer if run consistently at their optimum speed.

In the case of the oil pump, you are allowing oil to drain from the motor. So when it starts back up, the engine wear during those first few hundred cycles is going to be 1000 times greater than it would otherwise be. This will result in quicker loss of compression and deteriorating fuel economy in the later years of the engine's life, all but erasing any efficiency gains. Why subject yourself to all those additional risks just to save at most a hundred bucks IF (and only if) the price of gas were to go above $5 a gallon???? It makes absolutely no sense, in any country, under any scenario, and the people who brought this to market need to be fired.




RE: More than worth it?
By Shadowmaster625 on 12/31/2009 8:01:57 AM , Rating: 2
What if its cold outside? Are you going to sit there in traffic freezing your butt off because your motor stopped and you got no heat? Or if its electric heat, are you going to sit there and constantly drain your battery so that it needs to be replaced every 3 years instead of 5? Add another $20 to the price tag for that. And what if its 96 degrees outside? Good luck trying to run A/C off a battery... Yeah sure you could spike your A/C while the car is moving but then you are placing an extra load on both the motor and the A/C system while the care is trying to accelerate. There goes your fuel economy... Not to mention the lifespan of the coolant. Add another $20 to the price tag for that too. After all is said and done I bet the true average cost of this scam (with interest, amortization, tax, and increased component fatigue) goes over $1000. No one under any driving scenario, even a taxi cab driver, is going to save any money at that rate. Remember, most taxi cabs are bought with corporate debt issued at about an 8% rate. That ups the total cost of this option to well over $1000 not even counting component fatigue. So no, not even taxi companies would profit by purchasing this option. But I'm sure some of them will. (And they should be fired too.)


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