The UK firm Evolute Drives makes a multi-speed transmission system for hybrids and EVs that it says allows a vehicle’s traction motor to be smaller and more efficient by running it in a more power-efficient regime.

The company will present test results for its 3-speed MSYS transmission at the upcoming CTI Symposium in Shanghai. In independent tests, a demonstrator vehicle fitted with MSYS achieved a reduction in energy consumption of up to 18% compared to a single-speed vehicle.

“The results endorse our previous expectations of a 10-15 percent improvement when a single-speed drive is replaced by our MSYS transmission,” said Alex Tylee-Birdsall, Managing Director of Evolute Drives. “Reducing the energy required by an EV leads to a corresponding improvement in range.”

According to Evolute, the cone clutches used in MSYS allow greater torque transmission density than a wet multi-plate clutch, providing more than four times the torque capacity within the same package size. A novel twin-mode lubrication system also improves efficiency by increasing lubricant flow to the clutches during shift events, when greater cooling is required.

“MSYS allows full torque power shifts to be made but requires no energy to hold the transmission in gear, which improves system efficiency,” said Alex Tylee-Birdsall. “The key to the technology is the separation of the two functions provided by a synchronizer (friction and latching), while enhancing the friction capacity so it can be used to temporarily drive the vehicle.”

The company expects to finish testing prototypes in 2016 and release validated production units around mid-2017.

Source: Green Car Congress