For the last few years, the abbreviation 300 d has stood for the top engine in the range of four-cylinder diesel units produced by Daimler.
The premium vehicle manufacturer presented the latest version of this drive in 2018 with the new OM 654. Equipped with R2S® regulated, two-stage booster technology from BorgWarner, the engine complies with the strict Euro 6d-TEMP emissions standard – and at the same time impresses with remarkable dynamic driving performance.
The R2S® system from BorgWarner stands out thanks to its high efficiency and impressive compact design.
WWith a displacement of scarcely 120 cubic inches, the new turbodiesel from Daimler generates 241 hp (180 kW) and maximum torque of 368 lb-ft (500 Nm), which is already available from 1,600 rpm. The newly developed drive therefore has 20 percent greater maximum output than its predecessor. In the Mercedes C-Class and E-Class models, the engine thereby offers sporting performance with acceleration from 0 to 62 mph in around 6 seconds.
A regulated two-stage turbocharging system from BorgWarner generates the pressure needed for this. It combines a highly developed turbocharger with variable turbine geometry (VTG) for the high pressure range with a wastegate turbocharger as low-pressure stage. The VTG system employs patented S-shaped turbine vanes, which facilitate optimum adjustment of the exhaust gas stream to the specific operating situation of the engine. The compact high pressure stage is therefore capable of building up boost pressure very quickly, which provides the turbodiesel with excellent pickup from very low revs. As the engine speed increases, a bypass valve increasingly diverts the exhaust gas stream to the larger low-pressure turbocharger. The R2S® system from BorgWarner thereby guarantees consistently high power delivery, while at the same time offering outstanding efficiency.
Together with the R2S® turbocharger, which BorgWarner produces for the 176 cubic inch (2.9 liter) OM 656 diesel unit from Daimler (see TurboNews 1/2018), the newly developed R2S® turbocharging system is among the first two-stage solutions in the market to employ cast steel casings. The turbocharging system is equipped with a water-cooled electrical actuator and designed to handle high exhaust gas temperatures of up to 1,580°F (860°C). Yet despite this, the new R2S® system incorporates the two turbochargers in an extremely compact package, which further simplified integration in the OM 654 by Daimler.
R2S® – A success story
With its high efficiency and power density, the OM 654 represents another milestone in the successful cooperation between Daimler and BorgWarner. The turbo specialist has been developing sophisticated turbocharging systems for many years, both for the diesel and the gasoline engines of the renowned auto manufacturer. The R2S® regulated, two-stage booster technology from BorgWarner celebrated its premiere back in 2004.