Car features Stop-start systems

Stopping the engine usually shuts down car electronics

Stopping the engine usually shuts down car electronics

The simplest ideas are often the best. For instance, when a car is stopped, there’s no need for its engine to be running, so why not turn it off? 

Often, the reason is because it’s inconvenient, disruptive and means the radio, sat nav, heater, lights and other controls will also shut down.

Stop-start systems get round this by automatically turning the engine off when they sense it is worthwhile to do so – and, of course, automatically restarting it again. 

Crucially, though, the system leaves all the car’s ancillaries undisturbed.

In a manual car, the driver primes it by selecting neutral when the car comes to a standstill. The engine then shuts down, and starts up again – seamlessly – when the driver pushes the clutch. 

Official figures claim the saving on overall fuel consumption by doing this is 5%, with up to an 8% saving possible in town.

Stop-start isn’t new – VW introduced it on its ‘Umwelt’ Golf back in 1991. 

But, more recently, the BMW Group has popularised such systems, selling over half a million stop-start BMWs and Minis since 2006, and many more makers are now bringing the technology to market.

Other sections in this guide

  1. Overview
  2. Green cars explained
  3. Hybrid cars
  4. Diesel hybrid cars
  5. Hydrogen hybrid cars
  6. Hydrogen fuel cell cars
  7. Stop-start systems
  8. Brake energy regeneration
  9. Gearbox and aero tweaks
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