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

  • US transportation 'needs political leadership'
    November 9, 2012
    Long-time industry leader John Worthington reflects on where transportation in the US is heading – and where it should be going. Interview with Jason Barnes. The US’s new transportation bill reflects much of what is wrong in the sector in general and in ITS in particular, according to John Worthington. While a decision is welcome, he says, it does little more than provide certainty of funding for anything other than day-to-day operations. Worthington, former Chairman and CEO of TransCore, is back in the ITS
    Read More
  • Personal Rapid Transit, clear benefits for European cities
    July 26, 2012
    David Crawford watches the race to get the world's first PRT system up and running. To paraphrase the old joke about buses bunching, you seem to have to wait several decades for a Personal Rapid Transit (PRT) system, and then half a dozen come along together. Currently, in fact, there are well over that number of schemes for driverless electric passenger-carrying 'pod' networks at various stages of planning, design and implementation around the world. Locations range from a straight-off-the-drawing board ne
    Read More
  • Active traffic management increases safety and capacity
    February 2, 2012
    WSDOT is deploying Active Traffic Management in order to increase safety and capacity on its strategic roads. WSDOT's Patricia Michaud elaborates
    Read More
  • Hard shoulder running aids uniform traffic flow and safer driving
    January 23, 2012
    David Crawford detects a market for European experience. Well-established now in at least three European countries, Hard Shoulder Running (HSR) on motorways is exciting growing interest in the US. A November 2010 Report to Congress by the Federal Highway Administration (FHWA), on the Efficient Use of Highway Capacity, notes the role of HSR in the European-style Active Traffic Management (ATM) strategies now being recommended for implementation in the US where, until recently, they were virtually unknown.
    Read More

Highlighted Content