Clutchless multi-speed transmission for EVs

Transmission specialist Zeroshift has devised a multi-speed gearbox for electric vehicles (EVs) that needs no clutch.
February 1, 2012 Read time: 1 min
Zeroshift's multi-speed transmission concept changes gear without interrupting the torque, allowing EVs to run for longer at peak efficiency.

Transmission specialist 1994 Zeroshift has devised a multi-speed gearbox for electric vehicles (EVs) that needs no clutch. A damper inside the gear hubs and electronic control of the motor make ratio changes seamless. The company claims the innovation could enable manufacturers to downsize EVs’ electric motors, keeping them running longer at the medium loads and speeds where peak efficiency of over 95 per cent is possible. For drivers, that could mean more performance, greater range and longer lasting batteries.

Zeroshift’s managing director Bill Martin says: “Our studies suggest that by using a compact, multi-speed transmission and a smaller electric motor, manufacturers can gain an operating efficiency of up to 10 per cent. You can use that 10 per cent to improve EVs’ range or reduce the size, weight and cost of battery packs.”

Zeroshift’s concept prevents any torque interruptions during ratio changes and does not require a clutch, issues that have so far deterred EV manufacturers from fitting multi-speed gearboxes. Current EVs instead use a single-speed transmission, but the motor then spends more of its time outside of its optimum efficiency range.

For more information on companies in this article

Related Content

  • Lack of communication jeopardises road weather information
    February 3, 2012
    A lack of communications means that the case for more widespread use of road weather information systems is still not happening, says Vaisala's Jon Tarleton. More effective exchanges up and down the political scale are needed, he adds
    Read More
  • Digital Light Processing transforms travel information
    July 19, 2012
    David Crawford investigates the potential of new projection technology. Fifty years on from its invention of the microchip, US company Texas Instruments (TI) has compressed the technology into a surface area of just 4.3mm. As such, it forms the heart of a new Pico Digital Light Processing (DLP) system that is set to transform travel information delivery for millions of users on the move - by making it projectable.
    Read More
  • Federal Signal supplies all the elements of end to end tolling
    January 31, 2012
    Manfred Rietsch, group president of Federal Signal Technologies (FST), talks about the recent acquisitions forming FST and the organisation's plans for the future. "Our philosophy is going to be about open access" Federal Signal has been on a buying spree. An energetic policy of acquisition over the past few months has seen the company reposition itself as an end-to-end provider of Electronic Toll Collection (ETC) systems with what it states is a portfolio of proven, best-in-class technologies which will al
    Read More
  • Stepped speed limits improve workzone congestion and safety
    January 30, 2012
    Traffic flow has been improved, congestion eased and safety increased - by a system of 'stepped speed limits' introduced to UK roadworks. URS Scott Wilson principal consultant Jamie Uff reports
    Read More

Highlighted Content