Efficient Dynamics, Part II

By Jim Taylor, Editor MACS ACtion Magazine

Following up on our last post about BMW Group’s “Innovation Day 2012” in which they revealed and discussed developments in the company’s Efficient Dynamics program, here’s another bit of future tech that will be part of the “Predictive Power Management” system.

If you drive a manual shift vehicle, or know how to, you’re probably quite familiar with the act of downshifting for a curve or corner. The shift could be 6th to 5th for a fast sweeper, or perhaps 5th to 3rd for a sharper bend. Regardless, you already know performing the act is best done on approach to the corner, not in the middle of it; the lower gear provides some braking and keeps the revs up for better tracking and a spirited departure.

Unfortunately, today that entire rewarding and enjoyable concept is lost to 99.98 percent of those driving vehicles with automatic transmissions. Yes, paddle shifters or “slap stick” gear selectors are nice, but virtually nobody uses them—most drivers just “put it in D and go.”

But that’s not always the best or most efficient method of operation. The vehicle often enters the turn at a too-low rpm and with little exit torque available. By the time the ECU commands a downshift the car is just lumbering through and the downshift happens long after the need.

BMW says they are working on a solution by using the car’s predictive capabilities to increase its efficiency. They say the system can function “…just like an experienced driver travelling along a stretch of road he knows very well.”

The trick is using many of the existing sensors plus the on-board navigation system to predict the next corner, assess what’s needed and select the correct automatic gear range in advance. Essentially, the GPS says “Hey, sharp left turn ahead in a tenth of a mile” and the ECU says “Right, thanks” and commands a  downshift or two within the distance remaining. Naturally, the decisions are also modified by other sensor inputs – braking, vehicle speed and so on.

Although BMW didn’t specifically mention it, it’s also easy to see how a nav system could be programmed with elevation and terrain information as well, so the car would “know” when a hill was ahead or that it would soon need the “high altitude” correction factors for the fuel system.

We think this is one very cool bit of technology, and well worth it to any driver who is paying attention.  However, it’s also easy to see how the “just put it in D” folks will become easily flummoxed when the rpms increase, even slightly, while they’re on the brakes. Who will be the one to explain to our archetypical Mrs. Glockenspiel “why that number dial thing” gets higher every time she turns the car?  (Yeah, I really did have a customer call it that once.)

Like the fuel saving Start-Stop system BMW recently implemented here, this trans trick may end up with a driver-operated off switch, at least for US owners. Sigh.

The Mobile Air Conditioning Society’s blog has been honored as the best business to business blog in the Automotive Aftermarket by the Automotive Communications Awards and the Car Care Council Women’s Board!

When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.

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You can E-mail us at macsworldwide@macsw.org or visit to find a Mobile Air Conditioning Society member repair shop in your area. Click here  to find out more about your car’s mobile A/C and engine cooling system.

The 33rd annual Mobile Air Conditioning Society (MACS) Worldwide Training Conference and Trade Show, Be the Best of the Best will take place February 7-9, 2013 at the Caribe Royale, Orlando, FL.


About macsworldwide

Mobile Air Conditioning Society (MACS) Worldwide Founded in 1981, MACS is the leading non-profit trade association for the mobile air conditioning, heating and engine cooling system segment of the automotive aftermarket. Since 1991, MACS has assisted more than 600,000 technicians to comply with the 1990 U.S. EPA Clean Air Act requirements for certification in refrigerant recovery and recycling to protect the environment. The Mobile Air Conditioning Society (MACS) Worldwide’s mission is clear and focused--as the recognized global authority on mobile air conditioning and heat transfer industry issues. www.macsw.org
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