• Since full torque is available right from the start of an electric motor, single speed transmission have been considered adequate for electric vehicles. 
  • Most mass produced hybrids, example Honda Insight and Toyota Prius have CVTs, which are limited, in refinement and all round flexibility. 
  • However, the consumers desire for greater sophistication, smoother driving and higher battery range have propelled the necessity to produce a number of multi speed solutions for electric and hybrid vehicles.



  • Bary Warner argues that transmission efficiency is the basic factor to optimise the battery range and cost, besides, the motor and the generator can be operated in a more efficient range with the multi speed transmission. 
  • Thus, they have already developed a three speed version of their own single speed eGear drive, already being used in Ford transit connect electric, Tesla Roadster and CODA sedan. 
  • Their 3-speed version is to be used first in the Proterra Eco Ride BE35 electric bus.
  • Getray's two speed transmission is claimed to have energy efficiency gains of 8% compared to a single speed transmission, besides better performance. 
  • They maintain that "the first gear provides more acceleration torque from standstill; therefore, less nominally e-machine torque is necessary. 
  • The second gear provides speed, so the power is constant for the whole range. 
  • Therefore, the second gear can be chosen in regard to best efficiency." 
  • Thus, such an arrangement results in either higher battery range or a smaller battery and a smaller motor.
  • Zeroshift believe that multiple ratios enable peak motor efficiency for more of the drive cycle. 
  • According to them, fozr ratios would be optimal. 
  • So they are doing work on their AMTs for EVs and have reported 10% efficiency gains from simulations. 
  • They also have developed on 8 speed AMT for hybrid vehicles.
  • Aachen based FEV also believe that AMT structure is best suited for EVs and HEVs, being both efficient as well as inexpensive. 
  • As per them, the only drawback of AMT technology is the torque interruption loading to poor gear shift, which can be eliminated by actively synchronised shifts.
  • Regarding DCTs Borg Warner explains that DCT provides high efficiency and low parasitic losses in EVs, enabling smooth shifts without torque interruption. 
  • According to Getrag, DCTs enables a greater flexibility concerning cost, performance and fuel consumption.
  • In fact, many companies are now working with new ideas and concepts to develop ideal transmission for EVs and HEVs. 
  • ZF of Germany has its 8 speed automatic transmission with fully integrated electric drive, fitted on Audi AE and Q5 hybrids and the BMW Active Hybrid 7 model. 
  • It appears certain that soon single speed gear boxes for EVs or HEVs would be extinct.