Stop-Start Technology Saves Fuel

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The American Automobile Association predicts that by 2020, 8 million new cars will have stop-start technology. Vehicles with this feature automatically shut off when at a standstill and restart when either the brake is released or the clutch is reengaged. With estimated fuel consumption being reduced by as much as 12 percent, the obvious advantage of this technology is fuel conservation. Since all of us want to reduce our costs at the pumps, what's not to like — right?

Driving with Stop-Start Engine Technology

My first encounter with the new Stop-start technology was when I made my first stop during a test drive of a BMW 2013 X1. A red light in the center of dashboard came on, indicating that the system had been activated. Since the engine doesn't actually shut off until it reaches normal operating temperature, I didn't notice anything unusual until later in my test drive, while I was waiting to turn across traffic. When I took my foot of the brake and pressed on the accelerator, the engine restarted immediately, but the car seemed to hesitate, almost as though the engine was going to die. Although I now understand this sensation is not an indication of mechanical problems, it was unnerving. The idea that I might not have engine power when I need it will definitely have an impact on my confidence, particularly in high-risk circumstances.

Stop-Start Technology Drawbacks

  • Although you can deactivate the Stop-start feature on BMW vehicles, to do so, you must turn it off every time you start the engine.
  • In order for the vehicle's electrical systems, including air conditioning, to continue operating when the engine is shut down, a larger, more expensive battery will be needed.
  • The sense that the car is not going to accelerate quickly enough, makes starting after stopping an unpleasant experience.

My Recommendation

Undoubtedly, the Stop-start system will be instrumental in decreasing fuel consumption, particularly when your engine is idling for an extended period of time. It would be a great option to employ while in a traffic jam, but in normal driving situations, I see less of an advantage. Perhaps, in time, the cumulative fuel savings will convince me otherwise, but for now, I recommend that the consumer always have the option to deactivate the system.