Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Did you get a great deal? Let us know in the Values & Prices Paid section!
Meet your fellow owners in our Owners Clubs

Do Stop-Start Systems Really Save Fuel? | Edmunds.com

Edmunds.comEdmunds.com Posts: 10,059
edited July 2017 in Editorial
image
Do Stop-Start Systems Really Save Fuel? | Edmunds.com

An increasing number of new cars are being equipped with stop-start systems that are designed to save fuel by shutting off the engine at stoplights. But do they work?

Read the full story here


«1

Comments

  • I live in a traffic heavy city, Los Angeles, this is a thing to have when half of your commute consist of sitting still.
  • 85se85se Posts: 11
    I drove a BMW 1 series (their old 2.0 N/A that was not sold in North America) with stop-start in Germany in 2011. Took about 10 minutes to get used to. Great system, even on what must have been older technology.
  • danielkrnacdanielkrnac Posts: 2
    edited December 2014
    At the moment, the best start/stop system we've tested is (by far) the one available in Peugeot and Citroen cars (from Valeo) and they've been using it for years. It uses a different way to start the engine - a reversible alternator which also acts as a an electric motor, in this case like a starter motor.

    The advantage to this is, that you can start the engine at any point, since it's permanently connected to engine by a belt. The alternator can even start the engine during the its turning off phase.
    Thus you don't need to lose time waiting for the gears of the conventional starter motor to engage. In theory you don't need the starter motor anymore, but you still do have it in all the cars I know of, that use this system.

    It also uses a capacitor to store the energy from recuperation for starting (instead of the battery, and this was well before Mazda i-Eloop system). That's why it's called a "micro hybrid" system, rather than start/stop.

    This video shows, how the micro hybrid works:

    We've tested the european version of the Cooper 1,5 and the 328i (almost - 428i) as well and although their systems are good, if not the best that use traditional starter motor, the Valeo one is superior. The reversible alternator makes it possible to shut the engine down even when the car's doing about 20 kph or below (with the manual gearbox). In the real world I was able to manage 4,1 l/100 km of diesel in my city test cycle (57 MPG) with a Peugeot 2008 with the 1,6 liter four cylinder diesel engine (e-HDI).

    I believe the next step is going to be a system, that can shut the engine off even at higher speeds.

    With regards
    Daniel Krnac
  • Now let's see some acceleration times from a standing start with the system on and off
  • Time for a real test like through a city go a few hundred miles to get real world results. And then see what happens when it's -20 outside ad you start/stop
  • Most system automatically deactivate under certain temperature, some even above 0°C. So I can answer you right away - nothing happens :) Also, most system deactivate, when AC is on.
  • thecardoc3thecardoc3 Posts: 5,050
    edited December 2014
    The start/stop systems have so many variations right now its hard to say what we will be seeing win the battle long term. Mazda's system knows which piston is on its power stroke when the engine stops, and they fire the injector and spark plug as well as engage the starter to help the engine start even faster.

    There are a number of system where the starter is permanently engaged and the flywheels have over-running clutches designed into them.

    The mild hybrid (Belt Alternator/Starter) designs have been around since GM first brought them out with the Malibu and Saturn Aura Greenline in 2007.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    I tried this out on a 2014 and I found the "stutter" of on/off very annoying. Maybe I'd get used to it over time.
  • phoulephoule Posts: 1
    I just bought a Ford F150. I knew nothing about stop start. I test drove it and did not notice it. But on my way home from the dealers which was about 14 miles of city driving, I did notice it. The first light I thought the car stalled. I even turned off the engine my
    self and started it again with line of traffic behind. I took off, next light same thing only that time I noticed when taking foot off break that it started again. I thought there was something seriously wrong with the truck. By the time I got home I realized that it was the way the engine worked, and I looked it up in the manual. It has taken me a little bit to get used to it.

  • I would love to know how much not just people who pause longer at stops signs will save, but for vehicles like EMS or service vehicles, some of whom may sit idling for HOURS. Yes of course shutting the engine off conventionally is best, but some people are not allowed to do that. If there was such a system in place that planned for the engine going off when idling, it could result in huge energy savings, emissions reductions, health benefits.

    Thanks Edmunds!
  • I think this stop start business is going to result in a host of long-term engine problems. I want my engine on ALL THE TIME. Screw \
    stop start.
  • Comparing the performance of stop-start systems by turning the system on and off leave one factor out of the equation, i.e., the added weight of the larger battery, the larger starter motor, the electric coolant pumps, etc. All of the additional mass will increase fuel consumption at all times the vehicle is in motion. The question is how much of the fuel saved when stopped compared to how much more fuel is required, to haul the additional mass around, when not stopped? While there may be an advantage for vehicles used in an urban area there is a distinct disadvantage for those used primarily for highway use. For my money if you need to worry about the saving of around 10% on fuel consumption you should trade your vehicle for a bicycle.
  • steverstever Posts: 52,462
    I don't haul a lot of tools or junk in my car unless I'm on a road trip, and even tossed a third row seat in one car. Probably save one, maybe two percent on gas. So a 10% gas savings is a pretty big number to me.
  • Don't forget that the battery on these systems is twice as expensive as a normal battery. The same goes for the starter. The battery has an expected 3 year life. In other words, these systems DO NOT save you any money. They only purpose is to satisfy the pot smoking idiots that think they can save the planet.
  • steverstever Posts: 52,462
    "The expected lifespan of a conventional flooded lead-acid starter battery is impacted minimally from the number of starting events. Rather, battery life is mostly impacted by limited charge times between frequent engine start events and from excessive discharge during engine-off events from accessory loads. The length of and the cumulative accessory power draw during each engine shutdown event has a direct and strong effect on battery longevity because of the depth of discharge. If the battery is returned to a full charge between engine starts, the effect on battery life is negligible or nonexistent." (SAE)

    Batteries Plus has Duracells for the Chevy Malibu - the start/stop variety cost $40 more than the non-AGM kind.

    Nothing is standing still either and the sub-systems are beginning to be powered by lith-ion second batteries and ultra capacitors.
  • The feature is unsafe. While the startup may be very fast, the shut off IS NOT. If at the moment you intend to take off, the engine decides to shut down, it can take a few seconds before the engine starts again, as the computer requires the engine to be fully shut off before it restarts. When it happens at the very moment you intend to pull out into heavy traffic, it is dangerous, as there is quite the delay before you are accelerating. I have this feature on my 2017 Jeep. It shut off, just as I was began to take my foot off the brake. the delay before it started and began began to take off meant the cross traffic in the intersection had to slam on the brakes to avoid hitting me.

    This feature needs to be outlawed before someone gets hurt.
  • joey2brixjoey2brix Posts: 463
    What a waste of research money! Let's get more computer controlled traffic lights. Keeping then traffic moving as much as possible would save millions of more gals. of fuel, and get us to our destinations faster.
  • WRONG TITLE FOR THIS STORY !!
    proper title should be
    Do Stop-Start Systems Really COST LIVES?
    Feb 14,2017
    I was stopped, exiting a paved driveway onto a 2 lane road.
    I was deciding whether to make a left turn across the path of a large truck that had just turned the corner 300 Ft away.
    The truck seemed to be lumbering along, so I made the decision to pull out across its path and make my left turn. Apparently the truck
    hit its peak Torque at that time and suddenly sped up, just as I pulled out!
    At this same moment, the engine had decided to shut itself off!
    I pressed the gas and nothing happened! The Escape rolled into oncoming traffic!
    Not knowing WHAT to do, I pressed it to the floor, the engine started up
    and sat there THINKING in the path of the oncoming truck!!!
    I was stuck like a deer in headlights!
    My passenger and I could easily have died and no one would be here to tell about it.

    I suggest selling Ford stock short. They are bound to have a lot of Class-Action law suits coming due to injuries and death.
  • hotcrocketthotcrockett Posts: 1
    edited July 2017
    My Toyota stop/start system works seamlessly and I highly recommend it. I have over 400,000 miles of city and highway travel with no issues. My engine will cut off anytime I let off the accelerator at any speed. The restart is very quick and smooth most people cannot detect it, yet power is always there when I need it. Gas mileage increases as much as over 30%. The technology in my car includes an electric air conditioner that continues to run when the engine is off, so the mpg remains high even in the heat of summer. When caught in traffic jams, my mpg goes up.
    I am interested in the F150's stop/start system design before passing judgement as others are doing on here.
    PS: The are no issues with my battery, it lasted 5 years before replacement and it is not extra large sized.
  • eriedudeeriedude Posts: 1
    The next step is to cut the engine going downhill and when the wind is over 10MPH and behind you. This is the dumbest idea that should be illegal. The people who thought this stupid idea up should be embarrassed not praised. My 2019 Equinox doesnt give me a choice (switch) and I would take the car back if I could. So annoying and scary.
  • GeorgenyGeorgeny Posts: 1
    First thing I do after starting my 2019 Ford Edge is TURN OFF the start stop. Hate it!! The only thing I dislike about my Edge. Traded a 2016 for the 2019 to get various new tech despite it having this system.
  • kyfdxkyfdx Everywhere, USAPosts: 126,124
    Georgeny said:

    First thing I do after starting my 2019 Ford Edge is TURN OFF the start stop. Hate it!! The only thing I dislike about my Edge. Traded a 2016 for the 2019 to get various new tech despite it having this system.

    Do you have to turn it off, each time you start the car? That would be a hassle.

    My wife's car saves that choice, even after the vehicle has been turned off. But, most of the time, we let it go. Traffic jams or downtown, we might turn it off.

    Did you get a good deal? Be sure to come back and share!

    Edmunds Moderator

  • thecardoc3thecardoc3 Posts: 5,050
    kyfdx said:


    Do you have to turn it off, each time you start the car? That would be a hassle.

    Yes systems with the on off switch usually default back to on for the next key cycle.

  • kyfdxkyfdx Everywhere, USAPosts: 126,124

    kyfdx said:


    Do you have to turn it off, each time you start the car? That would be a hassle.

    Yes systems with the on off switch usually default back to on for the next key cycle.

    Not my wife's car... 2017 BMW. It holds your choice from the previous cycle.

    Did you get a good deal? Be sure to come back and share!

    Edmunds Moderator

  • thecardoc3thecardoc3 Posts: 5,050
    kyfdx said:


    Not my wife's car... 2017 BMW. It holds your choice from the previous cycle.

    That didn't come that way from the factory. That was an update that BMW came up with to appease a lot of North American Owners. (SI B12 15 12)

  • luebcke_92luebcke_92 OhioPosts: 1
    I don't see how this saves fuel? I was thought and so was many others, that turning the engine on and off actually took more fuel then it does by leaving the engine idle.
  • kyfdxkyfdx Everywhere, USAPosts: 126,124
    What possible reason would they have to design it in, if it didn't save fuel?

    Did you get a good deal? Be sure to come back and share!

    Edmunds Moderator

  • thecardoc3thecardoc3 Posts: 5,050
    This technology is expected to save about one billion gallons of fuel per year that are wasted by letting cars and truck sit and idle.


  • berriberri Posts: 10,059
    I wonder if this is another of those things that comes out true in the artificial testing world of the EPA, but not so much in reality. When it is very cold in winter, or very hot in summer I'd start it back up rather than become uncomfortable. Some of these multi direction intersections can have you sitting there for 4 or 5 minutes, and then there is rush hour where you can find yourself sitting through several light changes before you actually get through the intersection.
  • DadBrad968DadBrad968 United KingdomPosts: 1
    I love the idea of Stop/Start technology. Some systems here in the UK are even micro-hybrids that start forward as the engine starts. It's a huge leap forward. I admit, it was. bit unnerving at first, but easy to get used to. I find some of the comments here (an on other forums) quite puzzling. While the rest of the world seems to be quick to take up their share of responsibility for the environment and want to save money, comments like "For my money if you need to worry about the saving of around 10% on fuel consumption you should trade your vehicle for a bicycle." seem out of place. If I drive 20,000 miles a year and I can drive 22,000 using stop start, I'm going to do so. That is a huge savings. In five years, you will have saved the equivalent of being able to cross the US three times FOR FREE.

    I am equally surprised by the Stop/Start "horror stories". Most of them sound like driver error or a lack of knowledge about the system and how it operates. Most of these systems cycle on in the length of time it takes most people to move their foot from the brake to the gas. Read your owners manual (that book you only ever opened to learn how to pair your phone and program the radio) and save yourself a lot of hassle.

    I'll take the cash savings and the environmental benefits any day.
Sign In or Register to comment.