3. Degrees of vehicle electrification

3.3. MHEV types according to location of electric motor

P0 - Electric machine is connected to ICE only via a V-belt

  • Electric machine of 12 V replaced by machine of 48 V
  • ICE torque boost, recuperation, start & stop
  • Cannot be mechanically separated from ICE.
  • Electric driving is not possible.
  • E.g. Audi A8 48V MHEV, mainstream technology, great benefit (CO2 / km) at low integration costs

P1 - Electric machine on ICE's output (couplted to crankshaft)

  • ICE torque boost, recuperation, start & stop
  • Higher power and torque than P0 (not limited by belt slip torque)
  • Cannot be mechanically separated from ICE, same speed.
  • Higher integration costs, problematic cooling, narrow installation space
  • E.g. 2009 Honda Insight

P2 - Electric machine on input of gearbox

  • Electric machine mechanically separated from ICE (clutch)
  • Electric machine of same speed as ICE (or higher)
  • Increased recuperation possibilities
  • Possibility of purely electric driving (P2, P3, P4), do not allow start & stop

P3 - Electric machine on output of gearbox

  • Electric machine mechanically separated from ICE
  • The speed is a multiple of the wheel speed.
  • Higher recuperation efficiency (P3 and P4)

P4 - Electric machine is coupled to axle or placed on the wheel

  • Electric machine mechanically separated from ICE
  • Possibility of independent wheel drive
  • Axle split hybrid topology option (ICE front axle, rear electric motor)