4SED: New 4 Speed Twin Motor Seamless shift EV Transmission, Patented design concept for EV’s and 4WD hybrids

“The 4SED is a patented design concept for electric vehicles that takes inspiration from DCT (Dual Clutch Transmission) technology, from which the 4SED takes all the benefits but not the problems in terms of weight, size, efficiency and cost.”

Vocis has designed and built two versions of the 4SED transmission, the first was for a high performance sportscar application which ran very successfully in prototype form. The second smaller version, was aimed at a more conventional city car application. The later hardware has been built into a running demonstrator programme in a very severe application using a Mercedes Vito minibus. This application, one of the winners of the 2012/2013 Niche Vehicle Network Annual Research & Development Competition, has been continually developed to a high standard of driveability and is available for assessment upon request


  • Completely seamless shifting capability
  • Up to 15% improvement in range due to more efficient use of battery energy
  • 1st Generation designs were produced in 16 weeks
  • 2nd Generation design is now complete and undergoing testing
  • Vocis Demonstration/Development vehicle is running and available for customer assessment upon request
  • Simple, patented, design is easily scalable for different application, motor outputs etc.
  • No clutches, no synchronisers, very simple actuation mechanism for low cost solution
  • Suitable for use with 48v motors for mild hybrid 4WD applications

To read more please follow this link.

4SED The Compact seamless-shift clutch-less transmission for electric vehicles