BorgWarner has announced that it is supplying its regulated two-stage (R2S) turbocharger for Daimler’s latest 2.9-litre six-cylinder inline diesel engine OM 656, which powers the updated Mercedes-Benz S-Class launched in 2017.

Meeting the requirements of state-of-the-art engine concepts, BorgWarner claims its advanced turbocharging technology contributes to enhanced fuel economy and improves torque, performance and exhaust gas recirculation rates even under full-load conditions while significantly reducing emissions.

“Due to its optimised design, our turbocharging solution helps automakers overcome challenging system placement demands such as a tight fit and high temperatures,” said Frédéric Lissalde, president and general manager, BorgWarner Turbo Systems. “We are pleased to support our customers by delivering our highly efficient R2S turbocharging technology to meet the highest possible standards.”

The first R2S turbocharger on the market to have a turbine housing made of very robust cast steel also features a water-cooled e-actuator, bearing housing and compressor housing. BorgWarner’s R2S turbocharging solution consists of two turbochargers arranged in series – a compact high-pressure exhaust gas turbocharger featuring the company’s latest variable turbine geometry technology and a larger waste-gated low-pressure one with ported shroud compressor. While running at low engine speeds, the small high-pressure turbocharger provides most of the boost and at the same time excellent response, so that the driver does not experience any turbo lag. With increasing engine speed, a bypass begins to open, so that nearly all of the gases flow directly towards the low-pressure turbocharger which takes over the main compression work to provide high boost pressures with excellent efficiency. Controlled by an electrical actuator, BorgWarner’s R2S turbocharging technology adapts quickly to changing situations for fast response and significantly reduced emissions.