Audi will introduce Valeo’s micro-hybrid ‘stop-and-start” systems in its RS5 sports coupe, a media report said.

Reuters said this was a sign the Paris-based supplier might be tapping new premium demand for the fuel-saving technology.

Volkswagen and Valeo both declined to comment to the news agency.

Unlike a typical alternator, which converts engine torque to electricity to power a vehicle’s circuitry and charge its battery, the starter-alternator can also re-start the engine in a fraction of a second.

The Valeo system delivers fuel savings of up to 15% by automatically shutting down the engine whenever a car is halted by a red light or traffic, with an in-step reduction of CO2 and pollution emissions in congested cities.

First introduced in 2004, the so-called i-StARS technology is a flagship product of Valeo’s EUR4bn ($4.6bn)propulsion systems division, with 3m units sold.

But, as Reuters noted, launch customer PSA Group and other volume manufacturers have since dropped it from new models in favour of beefed-up starter motors, a cheaper though less efficient stop and start solution.

The i-StARS system is beginning to find new markets, however, Valeo chief Jacques Aschenbroich told Reuters. “Demand for it is continuing to grow significantly,” the CEO said, predicting a double-digit percentage sales rise.

With the mild-hybrid RS5, which went on sale this month in Germany and in France next week, Audi becomes the first German premium brand to use the technology on its current vehicle lineup.

It is also planning a 48V mild hybrid setup for its flasgship A8 sedan, out next month. That system combines a conventional pinion starter and 48V, water cooled, alternator/starter with the pinion unit used only for cold starts.