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.
