Stop-Start Engine Hybrids

A stop-start hybrid is the simplest kind, but this minimal technology may become the most common within a few years. It is composed simply of an energy storage device—like a battery—and a beefed-up starter-motor that can also act as a generator.

Stop-start systems are also called idle-stop—because it puts an end to burning fuel and emitting pollutants when a conventional car would be idling.

In practice, the car’s engine control unit shuts off the engine when the car slows down or comes to a stop. As soon as the driver puts in the clutch, moves the shift lever, or accelerates, the battery powers the starter motor, which quickly switches on the engine.

Stop-stop systems are the lowest-cost hybrid alternative, but if fitted to large numbers of cars, they could substantially reduce fuel consumption and air pollution from idling vehicles, especially in crowded city centers. BMW has announced plans to put start-stop systems in all of its vehicles, without using the word "hybrid." Other carmakers, including Citroen, Mazda, and Mercedes-Benz are enthusiastically embracing the technology for its ability to boost efficiency at a relatively low cost.

List of Stop-Start Cars