View Single Post
      09-29-2011, 06:30 PM   #7
paul386
Second Lieutenant
18
Rep
274
Posts

Drives: 2011 X3 35i Jet Black
Join Date: Oct 2009
Location: Florida

iTrader: (0)

Quote:
Originally Posted by bmwF10 View Post
Isn't 300+55=355? Is the 335hp a typo or am I missing something here?
The N55's power increases roughly linearly as the RPM's increase. The electric motor's power varies parabolically with RPM with a peak power at 50% of its peak RPM. Add the complicated manor that the transmission controls the relative speed between the gas / electric motor and your peak HP is going to fall between the gas engine's peak and the gas engine's + electric motor's peak.

As a further note the gasoline engine's torque is going to be roughly constant (increasing linearly) in the mid range with low torque at the ends. The electric motor has a linearly decreasing torque with maximum torque at low RPM and minimum torque at peak RPM.

Why don't they couple the N20 with the EM? Seems to make a lot more sense... But this is the same strategy as Honda had with the Accord Hybrid. They coupled a 20HP electric motor with their larger (240HP) V6 engine. They got marginally increased efficiency with marginally better performance. It didn't sell well...
Appreciate 0