27 January 2012
BMW announced a new range of their M Performance models featuring a new, 6-cylinder, 3-liter diesel engine with three turbochargers. The engine—which appears to be the world’s first automotive diesel equipped with three turbochargers—delivers a maximum output of 280 kW (381 hp) and 740 Nm (546 lb-ft) of torque. This new engine will be available in BMW M550d xDrive (Sedan and Touring), BMW X5 M50d and BMW X6 M50d.
The maximum torque of 740 Nm is reached between 2,000 and 3,000 rpm, while the maximum power of 280 kW is available from 4,000 to 4,400 rpm. At 2,993 cc displacement, the specific power is 93.6 kW/L. Acceleration (0-100 km/h) and average fuel consumption figures for the respective models are:
- BMW M550d xDrive Sedan: Acceleration: 4.7 s; FC: 6.3 L/100 km; CO2: 165 g/km
- BMW M550d xDrive Touring: Acceleration: 4.9 s; FC: 6.4 L/100 km; CO2: 169 g/km
- BMW X5 M50d: Acceleration: 5.4 s; FC: 7.5 L/100 km; CO2: 199 g/km
- BMW X6 M50d: Acceleration: 5.3 s; FC: 7.7 L/100 km; CO2: 204 g/km
The M550d models meet Euro 6 emissions, while the X5 and X6 are Euro 5 vehicles.
The turbocharging system includes a large low pressure turbocharger and two smaller size high pressure turbochargers. One of the small turbochargers is activated at low engine speeds, just above idle. The large, low pressure turbocharger is activated at around 1500 rpm, while the second high pressure turbocharger is engaged at speeds of 2,700 rpm and above.
Other subsystems of the engine have been redesigned as well, including the combustion and fuel injection systems. Maximum combustion pressure has been increased from the 185 bar of the most powerful diesel engine in the existing BMW line-up to 200 bar. The upgraded, piezo common-rail fuel injection system operates at a maximum pressure of 2,200 bar. Up to eight injection events can occur per cycle, including three pre-injections, one main injection and four post-injections.