If you've shopped for a new car in the past few years, you've probably seen automakers touting new stop/start systems that can help save a little gas money. The concept is simple enough — if you're stopped at a red light or train crossing, you don't need the engine; if the engine isn't running, you're not wasting any energy. But what's really going on?
As the name implies, automatic stop/start shuts off the engine instead of it idling at a stop and then rapidly restarts the engine when you want to drive away. If you do a lot of stop-and-go driving, you're reducing emissions and saving fuel by not idling for extended periods. More important to the automakers, adding stop/start tech increases Corporate Average Fuel Economy (CAFE) figures, helping offset all those big SUVs being sold.
Automatic stop/start systems do present engineering challenges. The electric starter that was designed to fire your engine a few times a day now has to start the same engine every time the car comes to a full stop. Obviously, a starter that was designed for 50,000 start cycles can't suddenly be responsible for 500K start cycles, so automakers have phased in special starters to better handle the stress.