• mcirohybrid,hybrid,buick,malibu,bmw,mpg,fuel economy

Microhybrids Are Big MPG Boosters, Report Says

Buick,GM,eAssist,start-stop,fuel economy

Buick and other GM models have added stop-start under the brand of eAssist

In an otherwise lackluster year for the clean energy/clean tech sector, Clean Edge, Inc., in its Clean Energy Trends 2013 report, cites the trend to microhybrids as one of the more positive and lasting movements in the transportation sector. While much attention is focused on electric vehicles and plug-in hybrids, the group sees microhybrids, also known as start-stop, idle-stop-go, idle elimination, mild hybrid or other names, as contributing more to increased fuel efficiency than any other technology.

The technology has been on the market for more than a decade and at least 40 percent of the new cars in Europe and Japan already use it, but it’s on its way to the U.S. as well. The attraction for the auto industry is that this is a relatively cheap technology that delivers tangible fuel economy improvements and helps them along the way to the goal of 54.5 mpg by 2025.

The Clean Edge reports points to Johnson Controls, a 125-year-old Tier 1 supplier based in Milwaukee, WI, as the leader for American introduction of microhybrid technology, which has already shown up on several GM vehicles under the eAssist name and appears ready to spread to many more. It’s a relatively low-cost part of the overall hybrid package. Start-stop alone may add 5-10 percent to mpg numbers while coupled with regenerative braking and an electric-powered air conditioning compressor, that number could double based on European testing.

Clean Edge quotes Thanh Nguyen, technology planning manager for power solutions at Johnson Controls, as estimating $1,000 in start-stop and related technologies could get the average car to about 48 mpg by 2025. That cost is less than half of a typical full hybrid system (hybrid cars include start-stop as part of their fuel-saving package).

start-stop,BMW,fuel economy

BMW and other automakers have added start-stop technology to their cars.

The GM models use start-stop in a system that delivers up to 36 mpg highway, a 25 percent boost compared to the non-eAssist models. Other companies currently on the American market with non-hybrid start-stop systems include BMW, Mercedes, Porsche and Jaguar. Ford, Kia and the Dodge Ram pickup are the next ones expected to add the system.

Clean Edge cites Lux Research as forecasting that start-stop systems alone, not including full hybrids, will be found on eight million new vehicles by 2017, which would be four times the number of hybrids on the road today. Johnson Controls expects that by 2015 more than 35 million vehicles worldwide would employ start-stop systems. In addition to Johnson Controls, other companies supplying systems are Axion Power, Robert Bosch LLC, Delphi Automotive and Exide Technologies.

What Clean Edge has pointed out is a truism of the auto industry. Automakers will find the lowest cost solution to meeting regulatory standards that still satisfies customers. In start-stop systems, they appear to have found just the kind of tool they like to boost fuel economy while not compromising the overall performance of the vehicle or costing more than a consumer is willing to pay.

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About Author: Michael Coates

is editor and publisher at Clean Fleet Report and an internationally recognized expert in the field of automotive environmental issues. He has been an automotive editor and writer for more than three decades. His media experience includes Petersen Publishing (now part of The Enthusiast Network), Green Car Journal, trade magazines, newspaper and television news reporting. He currently serves on the Board of the Western Automotive Journalists.

15 thoughts on “Microhybrids Are Big MPG Boosters, Report Says

  1. Andy Cox
    June 5, 2016 at 9:38 pm

    To whom this message reaches,

    I would like to get more involved and knowledgable of the pbc and Li-Ion battery systems and how long it takes for them to recharge. I would like to launch an initiative to build a combo electric/gas stations across America. Please respond soon via email. My email is andy.cox0522@yahoo.com.


    Andy Cox

    • June 6, 2016 at 12:46 am

      @Andy Cox,
      That’s very ambitious and would entail a multi-million dollar investment (you can check with Tesla to see how much their proprietary system is costing, though they’re a little vague on some of the financial details). Several companies (eVGo, ChargePoint and ABB for example) appear to have similar ambitions and at least in California the public utilities are about to join the group. In addition to the expense (and part of the expense) is this is an area with plenty of government regulation that must be dealt with. There are many points of involvement; one place to start would be to check out Plug-in America’s take on the situation on their website–http://www.pluginamerica.org/why-plug-vehicles/ev-links-resources (this page has a wealth of information on charging stations and a variety of related issues about EVs). Good luck. –ed.

  2. Simon S
    April 8, 2013 at 8:59 am

    A good solution is the Lithium Titanate chemistry. This particular chemistry has beed verified to be reliable at over 10K cycles, better than any Lead -Acid Batteries. They also have high charge and discharge capability, hence overcoming the limitations of Lithium Ion. Finally, they allow very deep discharge without harming the life of the battery hence a smaller battery pack is possible and therefore reducing the cost. It has a slightly lower energy density than Lithium Ion, but since you can use a smaller pack (due to deeper discharge) then that disadvantage becomes null. The only drawback is that it is still not available in large volume but there is a major Japanese battery supplier that is just starting production.

    The advantages of this chemistry is that it has the advantages of Supercapacitor, the Lithium Ion and the Lead Acid battery rolled into one, while avoiding or diminishing the limitations of these technologies. I have not done a complete comparison vs Lead Carbon Batteries so take this into consideration

    • April 8, 2013 at 11:53 am

      The work on battery chemistries continues to progress. Are these type of batteries being used in the Mitsubishi i and Honda Fit EV, which would indicate they’ve been able to scale them up somewhat?

  3. Chip Bremer
    March 20, 2013 at 11:55 am

    Michael, I certainly appreciate the article and even some of the comments posted here. However, it appears that no one is taking into account the recent technological advances by some battery manufacturers (as a result of research done by the Advanced Lead Acid Battery Consortium) that have resulted in the production of lead-carbon batteries, or advanced lead-acid batteries with specific carbon additives. These new batteries offer significantly enhanced performance over current AGM and other VRLA batteries, and several projects have demonstrated their ability to handle multi-cycle, partial state-of-charge applications such as in mild- and micro-hybrid vehicles (see UltraBattery by ALABC and CSIRO, .

    In fact, several AGM batteries with added carbon are already in operation in Europe, and they are producing greater functionality than simple start-stop systems and producing fuel savings in excess of 20% without loss of performance. One novel approach that maximizes this effect is the LC Super Hybrid project by ALABC and Controlled Power Technologies (http://www.alabc.org/publications/intro-lc-super-hybrid), which combines a lead-carbon battery by Exide with an electric supercharger and an integrated starter generator.

    Lead-carbon batteries are already making their mark on the industry (in stationary and automotive), and with even more participation and recognition by automakers and suppliers (already highly-anticipated), you can be sure that the impact will be even more significant in the micro-hybrid over the next several years.

    • March 20, 2013 at 10:53 pm

      @Chip Bremer,
      The battery industry is full of folks promoting the latest and greatest configurations and formulations. I’m not a chemistry expert, but I know that the auto industry has one tried-and-true approach to new battery technology. They hand it over to their durability testers who spend several days or weeks trying to break them. And, as one once told me, they are always successful. That said, every automaker out there is looking for the magic battery that provides performance, durability and low cost. If the formulations you mention can meet those three parameters, I’m sure well be seeing them soon.

  4. Let's Clarify
    March 14, 2013 at 12:03 am

    Let’s clarify some confusion.
    Plain stop-start idle elimination is also called “micro-hybrid” and that is where virtually all the AGM lead acid batteries are being used in Europe. Not lithium.

    Lithium is rarely if ever used for this simplest level of hybrid mostly because of its expense. Five-fifteen percent reduction in fuel is expected. The GM e-assist is more elaborate, a so-called mild hybrid not a micro hybrid. It does a lot more than start-stop. That is how they can get the 25% fuel improvement mentioned by Coates and afford that lithium battery (barely). It proves nothing for basic start-stop which is the most common and affordable system made.

    Regarding AGM failures in basic start-stop (micro-hybrid), the car keeps working. The driver may notice that the car does not turn itself off anymore when stopped or not as often. The driver may not pay attention as it works like a normal care without stop-start, drives the same. Many drivers don’t notice or are not bothered, or not bothered enough to complain, or if they complain will be wrongly told it is the fault of how they drive. But fuel use is affected.

    • March 14, 2013 at 3:06 pm

      @Let’s Clarify Thanks for the additional detail. Sorry if there was any confusion. The AGM batteries are used in the majority of applications, which are in Europe. Start-stop is the building block, though, that manufacturers must add to to meet EU CO2 and US CAFE standards.

  5. greg zulauf
    March 13, 2013 at 10:27 am

    It is important to note that the PbC has rapid charge acceptance unlike the Li-ion. The PbC- after a stop-start cycle will be recharged by the time the auto gets three blocks to the next stop light. The Li-ion may not be recharged, thus increasing fuel use to get to full recharge. The PbC seems to have the best characteristics of the AGM battery and capacitor all in one package.

    • March 14, 2013 at 3:26 pm

      @greg zulauf PbC batteries are definitely in the mix, but don’t appear to be winning in the marketplace. Do you have any data to show otherwise?

  6. Ed
    March 13, 2013 at 5:48 am

    Microhybrids can be idle-reduction, or engine-load smoothing (e.g. accel boost plus regen braking), or both like the first generations of Prius’. Both are relatively simple to manufacture now and have pretty credible financial payback without incentives on the right drive cycle and annual mileage.

  7. batterygeek
    March 13, 2013 at 4:52 am

    Nice article. You are one of the first writers trying to explain to the public that micro-hybrids are coming in a big way. One would think that not wasting gas while the engine is idling would be a simple fix. But as Start Stop guy points out, it is very hard on the battery. Running the accessories of a vehicle takes 90% of the power of a regular starter battery. Starting the car takes only 10% of the power. The load placed on the battery is extremely destructive to a battery.
    Your stating that you are skeptical about the failure of AGM batteries as described by Start Stop Guy. In this graph, produced by BMW in 2010, testing proved that in as little as 8 months an AGM battery goes from accepting a charge in 10 seconds to accepting a charge in 1000 seconds. The Axion PbC lasted 7.5 years until it got to the same stage.
    ( The graph is the 2nd graph in the following article

    I have been reading all the hype about advanced batteries for years. JCI, Exide,and East Penn are geared up for AGM battery sales but the truth of the matter is this: Start/Stop applications kill the charge acceptance properties of every AGM battery produced. The PbC battery is fairly inexpensive and works.
    Lithium is dangerous ( think Dreamliner) and expensive.

    Automakers care about meeting government regulations right now, more than customer satisfaction. When customers demand a S/S system that works for the long haul, the manufacturers will use a better product.

    • March 14, 2013 at 3:31 pm

      @batterygeek Good info, but I’d beg to differ with your comment about the automakers and customer satisfaction. There’s not one out there that doesn’t understand they have to get customers for the long haul to keep in this business. Not that there aren’t lapses, particularly when it comes to measuring the cost/benefit of an item, but I see a big trend toward overengineering that’s producing cars good for 200K miles compared to cars from 20 years ago that were lucky to make it to 100K. All of the added electronics and advanced technologies work against this trend, however. As I mentioned to Greg, I’ve seen the hype on PcC batteries, but where are the customers?

  8. Start Stop Guy
    March 12, 2013 at 9:29 pm

    Thanks for helping to get the word out about this important, underappreciated trend. The next step is to get the word out about what works and what doesn’t. For any start-stop hybrid “flavor” except the lightest one, the most common, least expensive current solution is to use AGM batteries. Unfortunately, there is a big scandal brewing there, as AGM batteries fail in their start-stop function within just a few months. The demands placed on AGM batteries are just too much for them to handle. JCI and Exide and the auto makers know this, as do an increasing number of consumers in Europe. Here in America, the consumer is much more litigous and active, though, so look for a better battery.

    There are two realistic choices for that better battery: 1) lithium-ion, which is high-priced by itself and requires expensive system support (e.g., thermal management and/or equalization circuitry), is at times dangerous, is not economically recyclable, but is somewhat available at scale, and 2) Axion Power’s PbC battery, which is lower cost, needs no thermal management nor equalization circuitry, is very safe and completely economically recyclable, but is not yet available at scale. The only thing wrong with Axion’s PbC is that no one outside of BMW, GM, either Toyota or Hyundai, Norfolk Southern, Freightliner and many other large OEMs has ever heard of them.

    Note that I excluded Maxwell’s supercapcitor and LAB offering, as it only supports the hotel loads encountered during engine-off events for a maximum of 30 seconds. So it’s not a true start-stop solution—the supercapacitor boost just ensures that the system, which uses an inferior battery, will be able to restart your engine.

    • March 12, 2013 at 10:55 pm

      @Start Stop Guy You raise some good points, but as you note GM is already using Li-Ion batteries and they’re the US leader in start-stop systems. If the currently used batteries are as bad as you say (and you’ll note some skepticism here), there is no way they will continue to be offered. Automakers’ warranty programs won’t tolerate it and the focus on customer satisfaction and competitive issues will keep pushing them to make sure the systems are functional and durable.

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