Zeroshift Previews Clutchless Multi-Speed Transmission for EVs

The development of a multi-speed gearbox for electric vehicles (EVs) that needs no clutch is underway, British company Zeroshift announced today, while also revealing details of the concept that could extend electric vehicles range and improve their performance. According to Zeroshift, the new transmission also increases the batteries’ life expectancy by up to 10 percent.

“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 percent. You can use that 10 percent to improve EVs’ range or reduce the size, weight and cost of battery packs,” Zeroshift’s managing director Bill Martin said in a release.

“The benefits of Zeroshift’s transmission would be greatest for electric delivery vehicles where the compromises in efficiency are greatest,” added Martin. “To be able to pull away fully laden on hills requires low gearing, but the motor then runs too fast and too inefficiently on the highway.”

Zeroshift’s concept prevents any torque interruptions during ratio changes thanks to a damper inside the gear hubs and the electronic control of the motor.

“By varying parameters such as fluid properties, peak pressures and end-of-travel speeds, we can tune the damper’s performance to suit different applications,” continued Martin.

Current range limitations often lead EV drivers to drain the cells to the maximum allowable level of discharge in order to reach their destination; the deeper cycling affects the batteries’ life expectancy. Improving the motor efficiency uses less of the energy stored for a given journey, easing the discharge-recharge cycles and reducing recharge time.