Start-stop System

In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby reducing fuel consumption and emissions. This is most advantageous for vehicles which spend significant amounts of time waiting at traffic lights or frequently come to a stop in traffic jams. This feature is present in hybrid electric vehicles, but has also appeared in vehicles which lack a hybrid electric powertrain. For non-electric vehicles (called micro-hybrids,) fuel economy gains from this technology are typically in the range of 5 to 10 percent.

Since automobile accessories like air conditioners and water pumps have typically been designed to run off a serpentine belt on the engine, those systems must be redesigned to function properly when the engine is turned off. Typically, an electric motor is used to power these devices instead.

This technology has also been used on Honda Motor scooters in Asian markets for the last decade. Their PCX 125cc model was released in 2010 to be sold in Europe with this technology, though their North American model does not feature it.