Idle stop saves fuel by shutting down the engine when the car is not moving, such as at a stop light. This feature has seen its widest and earliest dispersal in hybrid cars, but is starting to be adopted for standard gasoline engines. When you depress the foot brake for a stop, the engine shuts off. When you let the clutch out or take your foot off the brake, the engine starts up again.
These systems require a robust starter, and often cause a little hesitation in acceleration. Drivers can anticipate the green light, getting the engine running a little ahead of time. Idle-stop systems work poorly in stop-and-go traffic, where they cause engines to turn on and off multiple times within minutes.
Idle-stop systems have not seen much use in the U.S., except in hybrid cars, but are becoming more widespread in Europe. BMW added idle stop to the current model M3 to reduce gas consumption.
Example: 2011 BMW M3
September 29, 2011 5:04 PM PDT
Photo by: Mazda
| Caption by: Wayne Cunningham
Conversation powered by Livefyre