Start-stop gaining momentum
Question: I've read a few stories about new cars that turn off the engine at stoplights and start again every time you go. How much gas will this save? Wouldn't it use more gas to start back up? Would this wear out the starter?
— Jan Mueller
Answer: Stop-start, also called start-stop, is a fuel-saving and CO2-reducing trick borrowed from hybrid vehicles. Already in wide usage in Europe and Japan, it's beginning to gain momentum in this country, with a half-dozen or more vehicles offering it.
In a nutshell, the engine turns off at stoplights and promptly restarts as you release your foot from the brake pedal. Fuel savings are claimed to be about 10 percent to 15 percent in city driving, which could vary depending on actual driving conditions. Stopping and restarting an engine uses less fuel than leaving it running.
The 2014 Chevrolet Malibu, the first domestic mid-size vehicle to offer stop-start as a standard feature, utilizes a beefed-up starter motor, a larger and more robust absorbed glass mat battery, and an auxiliary battery in the trunk to provide accessory power during “auto stop” sessions. The brain behind the system looks at your air-conditioning setting, cabin and outside temperatures, vehicle speed and brake pedal pressure to decide whether it's appropriate to shut down the engine.
I drove a rented Malibu for several days to check this out and came away with mixed feelings on how it's implemented on this vehicle. Without the benefit of an owner's manual, I discovered auto stop only functions if the A/C button is pressed twice, which allows Econ mode. Additionally, auto stop functioned only when I pressed the brake pedal rather firmly at a full stop, as one would if you planned to remain absolutely stopped, and intuitively stood down when I was creeping and stopping briefly in heavy traffic. The only sense a driver has of auto stop occurring is the tachometer's drop to zero.
All lights and accessories remain on with nary a hiccup. During long stop lights, I thought this was very cool, as I wasn't using any fuel or producing emissions. The instant I released the brake pedal, the engine would restart, before my foot could make it to the gas pedal.
My only beef was startups weren't as smooth as hybrids utilizing an integrated electric motor system. During a few starts, there was a bit of an annoying jerk and rumble. I didn't attempt to record fuel economy numbers, as my driving was a mix of city and highway and wouldn't have been a reliable measure.
The added cost of a typical stop-start system is around $200-$300, and AAA forecasts this is recoupable in about 2-3 years of driving. I'm a bit leery of a conventional brush-type motor, pinion/ring gear-driven starter system, as there are quite a few hard-working parts to wear, as well as a battery that's much more expensive than typical.
I think I'd like the Malibu's auto stop system as well as I did the rest of the car if there were an auto stop “off” button, as found on most other stop-start vehicles.
If we were paying European gas prices, that little restart rumble and down-the-road maintenance costs would be easier to accept.
Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Email him at firstname.lastname@example.org.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Falling demand for steel not likely to reverse any time soon
- Aggressive drivers to face Progressive surcharges
- Tourists rush to visit Cuba before Americans
- Credit card use reflects confidence, flat wages
- Economy in steady, but poky expansion
- Dow Chemical, Olin in $5B cash-and-stock deal
- Heinz merging with Kraft in mega-deal; headquarters to stay in Pittsburgh
- Highmark delays payment to UPMC over in-network issue
- Stop foreign dumping, U.S. Steel CEO Longhi tells Congress
- Internet ‘one road in and out’ for rural users
- U.S. shale drillers try to keep costs competitive with oil from abroad