Many new cars come with automatic engine start-stop. These systems are designed to save the fuel wasted at idle by turning the engine off when you come to a stop.
These systems are becoming more and more common in cars and trucks. Even the Ford F-150 is arriving with this system as standard equipment, promising more MPGs.
But the fuel spent during idle seems insignificant, right? Even the EPAís fuel economy tests seem to downplay the significance of these systems. How much fuel can really be saved, and can everyone benefit from this technology, even if they spend most of their commute on the highway?
Hereís how it works for the driver: When you come to a stop, like you would at an intersection and hold the brake while you wait for the light to turn green, the engine will shut off. On cars with manual transmissions, you usually have to put the car into neutral in order for the engine to shut off. As soon as you let off the brake or engage the clutch, the engine will automatically and quickly fire up, so you can get on your way again. These frequent restarts require a different starter motor thatís more robust and paired to a different, tougher battery
Furthermore, unlike when you turn off your car entirely, the rest of your carís features will remain on even if engine start-stop system is active. That means you still get A/C, radio, navigation and all that. A bigger battery
helps with that, and some cars even feature an extra battery
or a super capacitor.
Still, despite updates to the new five-cycle EPA test, it may be hard to see the tangible benefits of anengine start-stop system.