Turns out, your car's engine is useless about a third of the time when you're driving. Bosch is using that math to estimate that the newest generation of its stop-start system could cut a car's overall fuel use by about 10 percent.

Most stop-start systems involved merely shutting off the engine when the vehicle comes to a stop (hence the name), replacing needless idling in the process. The German automotive components giant says its new system shuts down the engine as soon as the foot's taken off the gas pedal, indicating that all coasting can be done engine- and fuel-use-free. The company is also touting the system's faster restarts and says it can be used with gas-, natural gas- or diesel-powered vehicles.

It was reported last month that Ford will expand its stop-start function beyond its 2013 Ford Fusion to larger, more gas-guzzling vehicles like the F-150 pickup. The Blue Oval has estimated that stop-start can save drivers more than $1,000 in refueling costs over five years. Meanwhile, Mercedes-Benz parent Daimler is trying to gain some points with the emissions gods (actually the US Environmental Protection Agency) by claiming that the benefits its stop-start technology has on its fleetwide fuel economy is being underestimated. Daimler is shooting for an additional MPG worth of credit, saying its cars are idle about 24 percent of the time, not the 14 percent estimated by the EPA. Math is fascinating. Check out Bosch's press release below.
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Automotive technology

Start-stop system with coasting mode

New Bosch system stops the engine when the vehicle is traveling at speed, helping cut fuel consumption by 10 percent

Noise-free, zero-emission coasting phases 30 percent of the time

Function can be combined with any type of combustion engine

Economical system cuts CO2 emissions in real traffic conditions

Dr. Rolf Bulander: "Start-stop coasting will become an everyday feature in cars - just like air conditioning."

December 10, 2013

With its new start-stop coasting function, Bosch enables drivers of vehicles with combustion engines to travel in zero-emission, noise-free, and low-resistance mode over large parts of their journey. This innovative technology stops the engine when the vehicle is in motion, so that it does not consume any fuel. Whenever the vehicle can maintain its speed simply by rolling – for instance on a gentle incline – the engine is stopped. As soon as the driver touches the gas or brake pedal, the engine starts up again.

Tests carried out by Bosch have shown that the combustion engines runs needlessly about 30 percent of the time, meaning that the vehicle could simply coast for about a third of every journey. Although these phases are not taken into account in the New European Driving Cycle (NEDC), under real traffic conditions the function will give drivers a roughly 10 percent fuel saving. "The start-stop coasting function is affordable, can be combined with any type of combustion engine, and substantially reduces fuel consumption," says Dr. Rolf Bulander, member of the board of management of Robert Bosch GmbH.

Much of what makes the system innovative is its enhanced software and the use this makes of existing sensor data. Furthermore, the start-stop starter has been configured to cope with greater loads and to deliver faster restarts. In other respects, the system requires few additional components and can be integrated in just about any vehicle in the world. Whether they drive diesel-powered cars in Europe, gasoline models in North America, or CNG-powered vehicles in Asia, drivers everywhere stand to benefit from the new technology – as does the environment. After all, reduced fuel consumption also means lower CO2 emissions. In Germany, some three million new vehicles were sold in 2012. According to statistics, the annual average distance driven is around 11,500 kilometers. If every new car were equipped with the coasting system and emitted just ten grams less CO2 per kilometer as a result, the theoretical annual reduction in CO2 would amount to over 30,000 metric tons.

Soon everybody will be coasting
Today, thanks to double-clutch transmissions, some vehicles already have a "light" version of the coasting system on board. As soon as the drivers take their foot off the gas pedal, the system switches the engine to idle. While this means the vehicle is doing no more than rolling, it is still consuming fuel in order to keep the engine ticking over. Bosch start-stop systems, which have enjoyed success all over the world, stop the vehicle's engine altogether. The first generation of the system stops the engine only when the vehicle is completely stationary, while the enhanced start-stop system cuts the engine as soon as the vehicle is coasting to a halt – for instance at a red light. In contrast, as soon as the driver's foot is off both the gas and the brake pedal, vehicles equipped with the new start-stop coasting function stop the engine while the vehicle is in motion. That saves even more fuel. And because the engine is disengaged, the vehicle can coast for longer than it could with an overrun fuel cutoff system, for example.

"Bosch is confident that start-stop coasting will soon become an everyday feature in cars – just like air conditioning," says Bulander. Bosch is embedding fuel-saving functionality in many of its innovative products. One example is eClutch, which makes it easy to offer the coasting function even in vehicles with manual transmissions. As soon as a coasting phase is possible, eClutch decouples automatically and the engine is stopped. The coasting function is also available as an add-on for the Bosch entry-level hybrid, the boost recuperation system, to help it save even more fuel. Equipped with a more powerful generator and a compact lithium-ion battery, the 48-volt hybrid saves around 15 percent of fuel through electrification alone. In real traffic conditions, and fitted with the coasting function that shuts down the engine, the hybrid can achieve fuel savings of an additional ten percent – or 25 percent overall. The newly developed, economical Bosch start-stop coasting function can operate with any combustion or hybrid engine and thus has a wide range of applications. That is one reason why it was voted "Most Innovative Technology" in the "Green" category at the Dinner for Winners event hosted by German auto industry journal Automobil Produktion.
Automotive Technology is the largest Bosch Group business sector. In 2012, its sales came to 31.1 billion euros, or 59 percent of total group sales. This makes the Bosch Group one of the leading automotive suppliers. Its roughly 177,000 Automotive Technology associates worldwide mainly work in the following areas of business: injection technology for internal-combustion engines, alternative powertrain concepts, efficient and networked powertrain peripherals, systems for active and passive driving safety, assistance and comfort functions, technology for user-friendly infotainment as well as car-to-car and Car2X communication, and concepts, technology, and service for the automotive aftermarket. Bosch has been responsible for important automotive innovations, such as electronic engine management, the ESP® anti-skid system, and common-rail diesel technology.

The Bosch Group is a leading global supplier of technology and services. In fiscal 2012, its roughly 306,000 associates generated sales of 52.5 billion euros. Since the beginning of 2013, its operations have been divided into four business sectors: Automotive Technology, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 360 subsidiaries and regional companies in some 50 countries. If its sales and service partners are included, then Bosch is represented in roughly 150 countries. This worldwide development, manufacturing, and sales network is the foundation for further growth. Bosch spent some 4.8 billion euros for research and development in 2012, and applied for nearly 4,800 patents worldwide. The Bosch Group's products and services are designed to fascinate, and to improve the quality of life by providing solutions which are both innovative and beneficial. In this way, the company offers technology worldwide that is "Invented for life."

Further information is available online at www.bosch.com and www.bosch-press.com, http://twitter.com/BoschPresse.


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    • 1 Second Ago
  • 18 Comments
      alcameron78
      • 1 Year Ago
      Probably more than 10%. We have some major intersections that take 5 minutes to make a turn as we sit through 2 or 3 cycles of red lights, just to enter the intersection.
      paulwesterberg
      • 1 Year Ago
      10% improvement is not enough. If you are going to add stop/start you might as well go full hybrid and capture braking energy which would further improve fuel efficiency and save money on brake repairs.
        Camaroman101
        • 1 Year Ago
        @paulwesterberg
        Automakers would kill for another 10%, the only problem now is that the epa doesn't recognize start-stop as a gas saving feature so it's not worth it.
          2 wheeled menace
          • 1 Year Ago
          @Camaroman101
          Yes, that is the problem. It is basically an anti-incentive. You make the car a little more expensive but cannot say that it gets improved fuel economy.
          Joeviocoe
          • 1 Year Ago
          @Camaroman101
          Yep... they do not really simulate coasting well on the EPA tests.
          Rotation
          • 1 Year Ago
          @Camaroman101
          The EPA does recognize start-stop as a gas saving feature. The problem is the auto manufacturers want more credit than they get. But just because they want more doesn't mean they should get more.
        2 wheeled menace
        • 1 Year Ago
        @paulwesterberg
        10% is a lot for such a simple improvement. An average car already has the battery and alternator which make these things possible. There is a lot of bang per buck in just adding this feature alone.
          Matt Fulkerson
          • 1 Year Ago
          @2 wheeled menace
          Paul, isn't upgrading to a full hybrid 10x the cost of stop start? So the mileage gains achieved with stop start are much higher per dollar using your numbers.
          paulwesterberg
          • 1 Year Ago
          @2 wheeled menace
          30mpg vehicle gets 10% improvement -> 33mpg. Most full hybrid vehicles realize a much greater mpg improvement. Ford Fusion: 29mpg hybrid(+3,370): 47mpg Hyundai Sonata: 27mpg hybrid(+2,100): 37mpg Honda Civic: 32 hybrid(+2,100): 44mpg Honda Fit: 30mpg Honda Insight(+$2,300): 42mpg These hybrid systems will save you a lot of fuel and come at a pretty reasonable cost, and because hybrid systems can use instant electric torque for launching the vehicle they can often offer better low speed acceleration. Stop/start systems rely on the gas engine entirely so there is always going to be a little more acceleration lag and since they don't save as much fuel to make sense financially it would have add less than $500 to the retail cost of the vehicle. This site makes it easy to compare normal ice vehicles vs hybrid models: http://www.fueleconomy.gov/feg/hybridCompare.jsp
      Rotation
      • 1 Year Ago
      Isn't this what BMW calls "sailing" and has been doing with their European models already?
      Anderlan
      • 1 Year Ago
      The old routine where you're idling and you press on the pedal most of the way down for a VROOM and then another time for another VROOM will no longer sound like tugatugatugatugaVROOMtugatugatugaVROOM but ...silience...tugaVROOM...silence...tugaVROOM.
      Anderlan
      • 1 Year Ago
      I'm guessing Prius style hybrids with disconnect the ICE from the tranny when coasting (and eventually cut off the engine on long coasts). There's always braking that seems like you're on the lowish end of a gear but that's the constant coasting low-level regen if I'm not mistaken.
      Technoir
      • 1 Year Ago
      I used to shut off the engine while going downhill and could in some cases go for several miles...... the only issue was that hydraulic pressure is lost and you only have enough left to stop once with full power.
      goodoldgorr
      • 1 Year Ago
      I will be interrested to buy only if we can desactivate this systen cuz i live in a place that have rouph winters and i need heat to defrost the windows all the time.
        Technoir
        • 1 Year Ago
        @goodoldgorr
        People on here say the darnest things.... The system would detect cold temperatures automatically and prevent it from turning off the engine. Do you think all the engineers involved did NOT think of that issue? Really? Pfffff
          Marco Polo
          • 1 Year Ago
          @Technoir
          Technoir goodoldgorr, is not a man with much faith in your new-fangled idea's. His trusty old Neon, has been doing just fine and not failed him yet ! Once this technology is well proven, say for a reasonable period of, well,...20 years or so, goodoldgorr might be " interested to buy " ! In the meantime,......
          paulwesterberg
          • 1 Year Ago
          @Technoir
          The toyota prius has done this since forever.
        Rotation
        • 1 Year Ago
        @goodoldgorr
        Don't sweat it. The engineers will have programmed in many cases where the system won't turn off the engine. In fact, really the company only cares what their EPA MPG rating figure is, so they'll rapidly program in any exception which doesn't occur on the EPA test.
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