One of BMW’s humblest 5 Series – the diesel-powered 520d – will soon become a mild hybrid thanks to the addition of a starter-generator.
The new powertrain will incorporate the existing 2.0-liter diesel engine with its 190 hp (142 kW) and 400 Nm (295 lb-ft). Assisted by a 48V electric starter-generator, it will gain extra power and torque and improve its already impressive fuel efficiency even further.
The company introduces a new powertrain mode called Overboost, which will engage the electric motor briefly during intense acceleration phases. The same feature will also change the way in which the standard engine start/stop function works, automatically disabling the main engine when coasting. Both the start and the stop actions will be extremely smooth, the company promises.
The electric motor add-on will provide itself with free power thanks to a regenerative brake and a dedicated battery. Charging it will not be necessary, and even when fully discharged, the car will continue normal operation as a diesel-only vehicle until it gets enough juice into the battery again.
The premiere is scheduled for November. Both the sedan/saloon and the estate/wagon variants of the 520d (also both RWD and AWD) will be receiving the hybrid system.
In related news, BMW is currently testing the facelifted 5 Series, which you can see in our gallery and the video here.