Engine Stop-Start Systems

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Engine Stop-Start Systems on Nonhybrid Vehicles

Stop and Go All The Way: A hybrid staple trickles into normal cars with modest initial success.

From the April 201 1 Issue of Car and Driver (/rev iews/april-201 1 -table-of-contents)

Remember when Uncle Bill used to insist with absolute certainty that starting an engine burns more gasoline than

idling for an hour? Yeah, well, he was as wrong about that as he was about Ply mouth. Yes, a cold engine runs rich,

consuming more fuel than normal. For an engine already at optimum temperature, though, stopping and starting

does not use an excessiv e amount of fuel. This is why manufacturers hav e introduced sy stems that automatically

limit idling in a motionless v ehicle. Volkswagen debuted its first production stop-start sy stem in 1 983 with the

Europe-only Polo Formel E.

All these sy stems work similarly and are ubiquitous on hy brids. When the car comes to a stop, the engine computer

cuts spark and fuel. When the driv er lifts his foot off the brake, or engages the clutch, the engine fires back up.

Of course, the starter has to be stout enough to withstand the dramatically increased on-off cy cling. A heartier

battery is also required to satisfy the cars entire electrical needs with its engine off. Otherwise, stop-start is about as

easy a fuel-sav ing technology as driv ing downhill.

Mazda tried to complicate things in 2008 when it teased engine geeks with its theoretical Smart Idle Stop Sy stem

(SISS), which attempted the operation without rely ing on the starter motor. SISS would hav e manipulated the

alternator load to stop all four pistons exactly halfway through their stroke. To restart, the cy linder in its

compression stroke would get a small squirt of fuel that, when burned, would spin the internals backward just

enough to produce compression in the neighboring cy linder. That cy linder would then receiv e a normal supply of

fuel, and its combustion would spin the crank in the proper direction. Unfortunately , this elegant idea nev er

materialized, and Mazda went the more traditional route with its i-stop (/news/mazdas-efficiency-strategy-to-

include-stop-start-energy-regeneration-diesel-and-more-car-news), av ailable on 2.0-liter gasoline Mazdas

in Japan and Europe. The i-stop sy stem, though, does use an initial combustion blast to aid firing, easing starter

stress and reducing the restart time by half, to a claimed 0.35 second.

Ford recently announced that its stop-start sy stem, av ailable on some 201 2 cars and SUVs, has the real-world

potential to boost fuel economy by as much as 1 0 percent. Mazda, more concerned with EPA results, say s a 3

(http://buyersguide.caranddriver.com/mazda/mazda-3) with i-stop gains only one-tenth of one percent on

the EPA city cy cle. Therefore, U.S. Mazdas will do without stop-start until it can be part of a worthwhile package of

efficiency improv ements. (The Japanese city -cy cle test has 40 seconds of idling, so the cost of i-stop is justified there.)

CAR NEW S(HTTP://BLOG.CARANDDRIVER.COM/ZF-

ANNOUNCES-NINE-SPEED-AUTOMATIC-TRANSMISSION-FOR-FRONT-DRIVERS/)

(HTTP://BLOG.CARANDDRIVER.COM/ZF-ANNOUNCES-NINE-SPEED-AUTOMATIC-TRANSMISSION-FOR-FRONT-DRIVERS/)

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Ford t o OfferEn gin e St op/St a rton Non h y bridsBegin n in g...(HTTP://BLOG.CARANDDRIVER.COM/FORD-TO-OFFER-ENGINE-STOPSTART-ON-NONHYBRIDS-BEGINNING-IN-2012/)

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IN-EUROPE-ONLY/)

Ma zda 3 i-st opSt a rt s a n d St ops inEu rope...(HTTP://BLOG.CARANDDRIVER.COM/MAZDA-

3-I-STOP-STARTS-AND-STOPS-IN-EUROPE-ONLY/)

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PHOTOS (85) (/photo-gallery/engine-stop-start-systems-explained-tech-dept)

Canada is one market in which stop-start should succeed. Toronto has a law that makes idling in boats, cars, and ev en

buses for more than one minute per hour punishable by a fine of up to $5000. It would take a Mountie on ev ery

corner and may be the ghost of Lord Stanley himself to enforce it, but we admire the attempt to promote this simple

way of sav ing fuel. View Photo Gallery (/photo-gallery /engine-stop-start-sy stem s-explained-tech-

dept)

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Top Backfires Comments:

08:56 PM on 03/04/2011 Report

Alan LaRueSuper User

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I'd like to see this become universal just so my visit to Sonic Drive-in would be more pleasant. Seriously,

people, if you have to have the a/c on, go someplace where you can sit inside!

Speaking of which, is the air conditioner powered by an electric motor in cars that shut the engine off instead of

idling?

5 Replies

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03:41 PM on 05/13/2011 Report

invaderzim

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I read a great article somewhere where the writer said if you really want to save gas and reduce emissions then

make all stop lights 'smart'. That way they would change to green for the cars as soon as possible, rather than

being on a set schedule. Imagine all the hours of idling that would be reduced all across the US.

Something to think about next time you are stuck at a stop light waiting for the light to change away from the

directions that have no cars at all to green for your direction.

2 Replies

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12:11 AM on 03/13/2011 Report

john

nothing new, toyota started putting this on the carbureted 22r motor long time ago. this engine was so

technologically advanced that it actually grows more efficient over time. for example when it gets 15 -20 yrs old

, it refuses to idle. in fact it won't come back on till absolutely necessary , therefore saving fuel. it even shuts

off when backing up so that you save that fuel normally wasted when shifting to first. the gas guage stops

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off when backing up so that you save that fuel normally wasted when shifting to first. the gas guage stops

working as well, so that the driver will be less nervous about fuel economy and presumably have a more

relaxed driving style. most importantly, the 4wds , do not have enough power to go over interstate speeds, so

that the driver will not be tempted to exchange economy for speed. fortunately, the hilux lacked the buggy,

much maligned "start, crash" feature that plagued later camrys. this pedal feature prevented the car from

stopping , which saved untold amounts of fuel, but could never be fine-tuned.

1 Reply

Reply

08:53 AM on 07/12/2012 Report

Gary K.

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Took my 2006 X3 Sport in yesterday for it's 60K service. I'm driving a black 2012 X3 loaner. iDrive has trickled

down to the lesser models now so in order to drive it there is a learning curve. Naturally the dealer just tossed

me the "key" and sent me on my merry way. Since I just drove a new 335i in Feb I began looking for the slot in

which to insert the rectangular plastic electronic key. The 335i had the slot in the dash. After fumbling for what

seemed like an eternity while my 4 year-old daughter gave me puzzled looks from the back seat it dawned on

me that sticking a key of any sort into a dashboard receptacle is pass. Nowadays you just need to have the

key in the car. Anywhere in the car and all systems are go. Sure enough I stepped on the brake, hit the start

button and zoom, well, almost zoom, because now I have to figure out how to make it move forward. The

shifter, is of course, is a fully electronic switch that only moves sequentially one-click forward and backward

and it has buttons on it. Turns out the button on the side "unlocks" the shifter. If you don't squeeze it while

simultaneously jabbing the lever into Drive itRead more

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08:05 AM on 12/05/2011 Report

GruffDanSuper User

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I really don't like this feature on newer cars, I would want a way to defeat this built into cars with these

systems.

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12:12 PM on 09/09/2011 Report

Chip H

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Mazda, more concerned with EPA results, says a 3 with i-stop gains only one-tenth of one percent on the EPA

city cycle.

That's a 00.1% gain. Sounds like a huge waste of development time and money.

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12:22 PM on 09/03/2011 Report

kernals12

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If every car had a stop start system, it would eliminate pollution from start-stop traffic and help with noise

2 Replies

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03:32 AM on 02/09/2013 Report

Rexford Dundon

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have you heard a new car idling, they are so quiet when stock that you can barely hear the engine running

at all. The loudest thing you hear from almost any vehicle is tire noise on the pavement when they are

moving.

Voter Score 0

09:18 AM on 02/09/2013 Report

kernals12

Edit | Delete

you'd be surprised

Voter Score 0

08:05 AM on 08/31/2011 Report

08:05 AM on 08/31/2011 Report

gearhead4

Edit | Delete

I would accept these systems if I had a way to manually disable them. I test drove a Civic Hybrid and found

that the engine would shut off less than 1 second before I knew I needed to accelerate briskly to merge into

traffic. Talk about unnerving! The salesman said he did not know a way of overriding the system.

I ended up buying the non hybrid Civic and saved $5000.

Voter Score +1

Reply

01:27 PM on 08/20/2011 Report

Electric

Edit | Delete

Pretty cool. All long as the system is quick and seemless, then I guess it's all good. Cleaner air and better fuel

eco.

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Reply

01:00 AM on 08/18/2011 Report

Joe J.

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cars that have this system are missing 3 things:

1) Big battery pack

2) Electric motor

3) Regenerative breaking

Voter Score 0

Reply

04:34 PM on 08/15/2011 Report

anonymous

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Have you seen how people wait at red lights? They stop with odd spacings between cars then creep a little

here and there slowly taking up the gaps. That is a lot of starting and stopping of the engine.

Voter Score 0

Reply

10:40 PM on 08/02/2011 Report

James Phieffer

Edit | Delete

This is a smart idea for some situations (such as the interminable waits for lights during rush hour or at large,

multi-light controlled intersections). At one of the main intersections in my hometown, there are separate left

turn lights for both streets, meaning if you just miss your light, you will sit for about 2 mins. I often shut off my

car for this manually, and an automated system that uses an electric drive for the A/C would be great. When I

hit a half dozen such intersections driving from one part of the city to the other, with gas at $1.40/litre, it starts

to make a financial difference, while the additional manufacturing costs are minimal, since switching to electric

drive of accessories such as power steering and A/C is already happening as manufacturers work to meet

stricter CAFE requirements. And in that effort, every little bit counts.

Voter Score 0

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02:51 PM on 07/26/2011 Report

Scott VilleneuveSuper User

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Absolutely stupid on the Panamera and M3. Hybrids it may be effective...I suppose.

1 Reply

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02:01 PM on 07/31/2011 Report

Small M

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Agreed - my E90 gets about 12.5 city and 20 hwy the way I drive. A 10% increase would bet me like 14city

and 20 hwy (bet it doesn't cycle much at 79mph), but cost at least 0.3 sec from a stoplight? If I wanted tip

in I'd have gotten a mid range 5 series. The M3 doesn't even have an overdrive gear (top speed reached in

6th gear) and they want to shut them down at stoplights. Nonsensical.

Voter Score -1

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