(R)EVOLUTION - Starter-alternator

Starter-alternator – The key to Stop & Start

In the early 2000s, car manufacturers had a clear goal: to reduce the fuel consumption and emissions of combustion engines without sacrificing driving comfort. It was in this context that a discreet yet ingenious innovation appeared: the starter-alternator, patented in 2001.

As its name suggests, this device combines two previously separate functions: that of the alternator, which generates electricity to power the vehicle’s equipment, and that of the starter motor, which is used to start the engine. By combining these two functions, engineers created a compact and versatile system capable of smoothly managing the engine’s stop and restart phases.

The most striking innovation it enables is the automatic shutdown of the engine during prolonged stops — at a red light, in a traffic jam, or during a temporary stop. The engine cuts out, avoiding unnecessary fuel consumption. Then, when the driver presses the clutch or accelerator, the starter-alternator instantly restarts the engine, without any noticeable jolt or delay. Driving comfort is maintained, while offering a tangible energy saving.

This device is the technological heart of the Stop & Start system, which became widespread in the following years on a multitude of models, first in city cars and then across all ranges. Thanks to this system, reducing fuel consumption and emissions became accessible to the majority of drivers, without any particular effort on their part.

The starter-alternator perfectly embodies the logic of these transitional innovations: a technology that is relatively simple in principle, but with major consequences for energy efficiency and the environment. It also paved the way for the arrival of hybrid engines, which are based on the same idea of intelligent management of the combustion engine’s operating and shut-off phases.

Today, it is fitted in almost all modern combustion engine vehicles and many hybrids. Although discreet and often overlooked by motorists, the starter-alternator has helped to transform our driving habits and make cars more fuel-efficient and sustainable.