Mazda is intent on improving the fuel efficiency of its lineup of vehicles, even if it isn't going full-bore into electric vehicles. For proof, look no further than the automaker's SkyActiv technology. When it comes to the next stage in the company's efficiency plans, the award-winning i-Stop – the Japanese automaker's stop-start system – Mazda says the U.S. isn't ready for this fuel-saving tech quite yet.

Mazda says the $800 optional system, which yields five to eight percent fuel economy gains on Japan's test cycle, is a bust when tested by the EPA. It's for this reason alone that Mazda will deliberately delay the U.S. introduction of i-Stop. There is good news, though. Mazda says the technology will eventually make its way into vehicles sold here in the States, but not anytime soon. Look for i-Stop to slowly expose itself in the automaker's U.S. vehicles in 2016, says Jim O'Sullivan, chief executive officer of Mazda North America.

When attached to a direct-injection engine, the i-Stop system stops the pistons in a specific position when the car comes to a halt. Then, when the driver is ready to do, the system squirts fuel into a cylinder and ignites it to re-fire the engine. The engine restarts and returns to idle in one-third of a second.


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    • 1 Second Ago
  • 23 Comments
      paulwesterberg
      • 3 Years Ago
      Start/stop may be the poor mans hybrid. It might be cheap enough to add it to low end vehicles, but it wont provide the benefits of a full hybrid such as regenerative braking and electric launch. This just ads polish to the titanic deck chairs.
        guyverfanboy
        • 3 Years Ago
        @paulwesterberg
        If a KERS (kinetic energy recovery system) was added along with start-stop, this would make cars a micro-hybrid using a fly-wheel type energy recovery system without the full on expense of a full hybrid system.
          skierpage
          • 3 Years Ago
          @guyverfanboy
          No car has flywheel energy recovery except the Porsche GT3 R Hybrid race car. Meanwhile many mild hybrids have brake regen flowing to an oversized battery. (A regular 12V battery can't handle the power surge from substantial regenerative braking.)
      fairfireman21
      • 3 Years Ago
      I have not done any resurch on this yet, but I was wondering. How does this stop/start affect heating and cooling sence the motor is not running?
        danwat1234
        • 2 Years Ago
        @fairfireman21
        Probably the engine has an electric water pump so the heater core in the cabin can still heat up the cabin with engine heat even with the engine being off. Cooling? Nope I don't think it's electric and the lead acid battery + supercapacitor can't power that for long.
      • 1 Year Ago
      Has there been any further movement by Mazda concerning their i-stop tech release into US market. I'm looking at a M6 GT that does have i-ELOOP so I'm wondering about i-stop.
      uncle_sam
      • 3 Years Ago
      Using the EPA as excuse ist planly stupid. Why not offer it as option TO EARN MONEY. Most buyers know that the EPA is a testcyle and not real world condition. but if the seller offers a good start and stop system ppl would buy it. Mercedes make the same stupid excuse. Adding start/stop like in some product lines in germany as an extra feature is an extra value for the consumer, wether it plays a role in EPA or not. The Prius has the same problem in the cycle, all hybrids feature start/stop. so why not an ICE car?
        Spec
        • 3 Years Ago
        @uncle_sam
        "Most buyers know that the EPA is a testcyle and not real world condition. but if the seller offers a good start and stop system ppl would buy it." I seriously doubt that. If all other things are equal and one car has a 35MPG rating and the other a 33MPG rating, most buyers are going to buy the 34MPG car even if the 33MPG one is equipped with a start/stop system that could give them better mileage. People just don't have the ability to judge the effectiveness of the start/stop system.
      diffrunt
      • 3 Years Ago
      Right on ! Dave!
      PhilipJ
      • 3 Years Ago
      ahh i fckin hate the EPA! if anyone should care about an easy way to increase efficiency, they should. it shouldn't be this hard to change their testing procedures. the feds suck at everything
        letstakeawalk
        • 3 Years Ago
        @PhilipJ
        In the very least, this does illustrate the idea that automakers are making improvements based on how they cater to the EPA's test, and not to how they actually benefit the customer in the real world. If the tech will save a consumer money by increasing measured mpg, then who cares about EPA tested/rated mpg, unless Mazda is being held to some sort of standard (CAFE?). Here we have a good example of government regulation standing in the way of implementing a beneficial technology.
      2 Wheeled Menace
      • 3 Years Ago
      OK, why wait 5 years when the technology is already in use in Europe and Japan? i'm so tired of being behind.
      Dave
      • 3 Years Ago
      Forget the stop/start - Replace our traffic lights / stop signs with roundabouts so we don't waste so much fuel stopping and accelerating.
        sirvixisvexed
        • 3 Years Ago
        @Dave
        totally random of you to say, but I completely agree. In the towns around me i've seen over the years just a couple of traffic light intersections that were turned into roundabouts, and I swear they're actually a lot faster moving than the light was! How much auto efficiency is wasted and unnecessary emissions emitted from 15 cars stopping and idling so one can turn? I cringe when I watch such things. The traffic grid could be SO much smarter, resulting in faster trips and less pollution. Roundabouts would help in a lot of areas! There's even been plenty of times over the years during power outages where i've had to drive through busy roads when there was no power and no working traffic lights, and the thought that it was going to take me forever to get anywhere never proved true, because people using even a busy intersection as a 4 way stop still gets me to my destination practically the same amount of time.
          Dave
          • 3 Years Ago
          @sirvixisvexed
          "totally random of you to say" I spent a week driving around the UK this summer and learned to respect roundabouts. So, when I saw this article on stop/start, it was the first thing that popped into my head.
      Spec
      • 3 Years Ago
      I think people need to explain & understand the EPA issue here. As far as I understand, the current EPA testing regime does not really take into account start & stop driving. Thus, although start/stop systems would save a lot of energy in the real world for many consumers, the energy savings is not at all reflected in the EPA MPG figures. Thus, it would be nice if the EPA were to change their 'city' testing regime to make it more like real life city driving which involves a lot of stopping stop lights and being stuck in stop & go traffic. Since most people make their efficiency judgments based on the EPA MPG figure, the EPA MPG figure should account for this real-world energy savings.
        Rotation
        • 3 Years Ago
        @Spec
        The EPA city test includes a substantial amount of idling at a stop. It is quite possible the EPA test is realistic and the European one isn't. Just because Europes figures product higher boosts for stop-start doesn't mean the EPA tests should be modified to be similar.
        sirvixisvexed
        • 3 Years Ago
        @Spec
        "Since most people make their efficiency judgments based on the EPA MPG figure, the EPA MPG figure should account for this real-world energy savings." Gotta love what nearly a century of government dependent people yields! Who wants to think for themselves? Do their own research? Nobodyyyyyyyyyyy! Let's just look at a sticker and not put more than 3 brain cells of thought into it.
      skierpage
      • 3 Years Ago
      Mazda's system doesn't recapture energy when braking otherwise lost as heat, and it doesn't have an electric motor as the most efficient way to propel the car. People still think Toyota HSD is more complicated because it has two motor-generators and a continuously variable transmission. Look at the diagrams and you see the alternator and starter motor; you don't see the belt connecting the alternator, or a complicated transmission with multiple gears. Just replace all of that with a *simpler* HSD system for a big jump in mpg, and a path to the future. Mazda licensed it from Toyota, it's a a matter of cost and pride before they ship it.
      amtoro
      • 3 Years Ago
      What do they mean by saying the US is not ready yet? hybrids are the most commonly seen example of start-stop technology implementation. Have we been buying hybrids for 10+ years without being ready for them??
        Dave D
        • 3 Years Ago
        @amtoro
        This is not a matter of Americans liking or not liking hybrids. This is a matter of the EPA not putting realistic measurements in place so that stop/start systems don't show up on the "mpg stickers". People like you (I'm not being mean to you here, just pointing out that you either don't know the difference or didn't read the title closely enough) don't realize that this technology really saves fuel...and it is NOT hybrid, It is simply stopping the engine when you're sitting at the light. But the US EPA cycle doesn't measure this so the average person has no incentive to spend the money for this tech, because they don't realize it does anything.
      Peter
      • 3 Years Ago
      Say 5%-8% on a $2000 gas bill pa, that's $100 to $150 5 year payback (gas cost will escalate, versus opportunity and financing costs), longer if you do a lot of highway (like most Americans) is a tough sell if you can't put it on the EPA sticker
        sirvixisvexed
        • 3 Years Ago
        @Peter
        its a tough sell, which is a tragedy, because people don't understand that you can't compare used gas that has no value to a system of parts that you still own, that still has value. If it costs $800, you only need to save about $400 in fuel, because a used i-stop mazda is going to be worth hundreds of dollars more than a used non i-stop, the $800 system may even hold ALL of its value during ownership. But everyone continues to use the BS math about how you have to make up the cost of efficient hardware in fuel purchases, which is WRONG.
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