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.

Related Content

  • Machine vision makes progress in traffic applications
    June 2, 2014
    Machine Vision technology is easing the burden on hard-pressed control room staff and overloaded communications networks.
    Read More
  • Multiple patents granted for in-wheel electric drive
    March 22, 2012
    Protean Electric, a specialist in advanced in-wheel motors for the automotive industry, has been awarded 17 patents for the unique technology and design of its Protean Drive system. More than 60 additional patent applications have been filed internationally and with specific countries in North America, Europe and Asia. Protean Electric chairman and CEO Bob Purcell says his company’s in-wheel motor design is unlike conventional motors or combustion powertrains with electric motors added. "We started with a c
    Read More
  • Positive incentives an alternative to road user charging?
    February 1, 2012
    The Netherlands has been looking at incentivising rush-hour avoidance. The intention is to better understand road users' motivations and find alternatives to congestion charging. Something significant needs to happen if we are to adequately address the traffic congestion and other issues caused by the ever-rising numbers of vehicles on our roads. Congestion or distance-based charging is seen as one way of managing demand and raising revenue for improvements to transport infrastructure. However, charging is
    Read More
  • Intelligent powertrains could make cost cuts
    April 30, 2020
    Intelligent vehicle powertrains could be a way of making substantial cuts in operating costs and emissions. David Crawford looks at some far-reaching initiatives in Europe and North America
    Read More

Highlighted Content