AAA tests show 5-7% city mileage gain with automatic engine stop-start
 

Looks like the AAA is trying to educate motorists about the benefits of stop/start.

Their study also busts the misconception that stop/start isn't on American cars because the systems don't register enough of a beneift in EPA testing.

Source: AAA

They estimate annual fuel savings of $179 for consumers, based on 15,000 miles a year in a vehicle that averages 20 mpg with fuel prices at $3.65 per gallon.

Notably, they also point out the savings "do not include other factors relative to ownership costs of vehicles equipped with automatic stop-start systems, such as potentially higher costs to replace the upgraded battery or starter typically used in these vehicles."

Do you think AAA will ever do a study on the savings for "manual engine shutoff without coming to a stop," or EOC as we call it here?

I thought we did not have start-stop because Americans would not put up with the injustice of their air conditioning turning off.

It really seems like if you purchase a car that turns off your engine (or shifts to neutral), you are environmentally-friendly, but if you do it yourself, you are evil, insane, and putting everyone's lives at risk!

Everyone! Even if they are miles away!

Ooh, sorry. I'll have to buy another new car so that I'm not imperiling you guys any more. And the puppies, I've got to stop risking all those puppies' lives.

It's not impossible to get a 12-volt Danfoss-type compressor to keep the air-conditioneer operating with the engine off, just like in any hybrid.


Going "green" is nowadays more a matter of bragging rights or marketing than any other thing.

Don't forget the wolves.:rolleyes:

We mainly don't have start/stop because the EPA testing doesn't reflect any benefit. During the testing, there is no sustained periods where the vehicle is stopped and idling (or not). Its just speed up/down.

The A/C thing can be remedied by a little extra cost. Heat exchanger manufacturers have incorporated phase change material (wax) into the heat exchangers to 'store cold/heat' for a limited amount of time. I think in the article I read it was 30 seconds. The additional cost was pretty minimal.

Myself and several insight owners see more like a 10% savings with auto stop. :thumbup:

Well, people do not want their AC cutting out, and if they wanted to pay extra for better mileage, they would purchase a hybrid!

For the puppies? Wolves?
http://i299.photobucket.com/albums/m...pies/Quiet.jpg

Wolf puppies!

If you had actually driven a hybrid you would know the same applies to the heater. At least some cars like the Civic and prius can run the ac on battery power for a few minutes before the engine needs to refire. :thumbup:

Me? I use recycle for air flow and let off the brake every so often so the engine runs a little, then reapply brake and auto stop restarts.

FWIW, I have a car with Stop/Start and if the A/C settings are above a certain threshhold (relative to ambient) the S/S won't cut the engine. Some other brands use electric A/C compressors instead.

Re-read the first post. :P

That's the myth they busted. They ran the cars on the EPA urban cycle and reported a 5-7% gain.

And I imagine that most cars with automatic climate control will override auto stop if the cabin temp goes out of range (either cold or hot).

Haha, my bad. :)

The EPA lied to us?! :D

People over on that gas gasbuddy forum were I do a lot of recruiting say auto stop-start is "a stupid idea" and "wont save any fuel" and some how "the car will use more fuel by restarting it".

Lot of idiots out there.

Trust me auto stop-start is nothing new, cars sold in japan have had it since the 1990s.
Finely time we got to get a little 1990s technology in some of these new vehicles.

Some folks might think it would have some delay on the throttle response when the engine is turned on again, but it doesn't happen at all. Otherwise it could be a good excuse to get the BAS-hybrid system more widespread...

It would be interesting to see the demographics. Wonder how it would break out by age. People who started driving before fuel injection and HEI might be a lot less accepting.

I think when they say there was is NO benefit with the Epa test, they mean 5-7% isn't ENOUGH to offset the cost of the batteries, programming, and starters. 5-7% gain is probably more then other tests have shown using the epa standard because as pointed out the epa test doesn't have much idle time.

I also question exactly how they did the test. Did they disable the start stop of those cars and then run them with and without? Even then the savings they quote are based on numbers none of those cars deliver, and numbers based on future CAFE standards no cars will deliver. Saying a car with start stop installed but disabled loosing 5% efficiency, is not really the same as if that car was built without the added weight and complexity of the start stop in the first place may show less of a penalty. So based getting 30-40 mpg and seeing more realistic 3-4% improvement you would only be saving $50/year which should never pay for the initial investment and repairs of the system. On a hybrid it makes more sense, the stuff is already there and also allows for automatic EOC and pulse and glide.

Mazda’s Efficiency Strategy to Include Stop/Start, Energy Regeneration, Diesel, and More - Car News - Car and Driver

Here is start-stop without the additional hardware.

regards
Mech

Interesting strategy.

For those without a hybrid that has start/stop it would be interesting to know if the engine goes right into auto stop from dfcu(SP?) or does it burn a little gas before making that transition when coming to a stop.

I think that method makes an even bigger deal for mpg. :thumbup:

With the 1st gen Insight, you can usually get it to go into autostop at speeds below about 18 mph. And if you're on a downhill and are fairly careful, you can sometimes get it to stay in autostop up to 40 mph or faster.

In an Audi A3 that I have noticed the start-stop working, it did burn a little gas before stopping.

For 'safety' the engine won't stop unless the car is stationary. It will also restart if you exceed 5mph with the engine off (eg rolling down hill). UFI will DFCO down to idle so depending on the gear you're in it will use a little fuel in the transition. There's maybe 3 seconds of idle fuel used there.

I plan on installing a kill switch so I can EOC up to a stop, and have the car auto-restart when the light changes (mainly because S/S won't work with anything but the stock Pb battery, and I've got supercaps ready to go in). On the other hand, S/S on a turbo car still doesn't sit with me quite right.

Only time I visit gasbuddy anymore is when I'm feeling masochistic. The idiocy on the forums/comment sections there is way more than knee-deep; a guy could drown in it. :mad:

My '59 has "start-stop" on it right now- the idle screw has backed out and it stalls when I approach a stop. :P

Start / stop is just so anti-consumerist!

Yeah, I've had a vehicle or two like that. Yet another reason to love carburetors :-)

Gave 'er a little crank- it's all good. :thumbup:

Stop-start is theft from the state you capitalist pigs.
;)

As we say in Brazil, ladrão que rouba ladrão tem cem anos de perdão (a thief who robs from another one has a hundred years of forgiveness) :p

stop/start
 

Here's a dated article about start/stop,indicating a 7% mpg improvement
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