GM is working on a clutch for the transmission of electric vehicles

Electric vehicles do not require multiple gears, but they still have a transmission. And General Motors is working on ways to make them better.

A patent application has recently emerged from an automaker detailing a new type of clutch actuation for EV transmissions. It was published by the U.S. Patent and Trademark Office (USPTO) in 2024-5-16 and was originally filed by GM in 2022-11-10.

This document describes GM's use of hydraulic actuators to operate the clutches of automatic transmissions used in electric vehicles. The controller changes the pressure of the fluid in the actuator and opens and closes the clutch, depending on what the controller determines to be optimal in a particular scenario.

This setting is simpler than a conventional automatic transmission and is considered possible by the need to reduce the gear shift of the electric motor. GM said in a patent application. According to GM, "electric motor instability" inherent in other types of clutch actuation can also be avoided.

Using such a clutch setup, the motor can be detached from a series of drive wheels to improve efficiency. It also seems like a more likely application as most current EVs do not have a multi-speed transmission, making the most of the instantly available torque of an electric motor. The Porsche Taikan has a 2-speed gearbox, and Stellantis has patented a 2-speed transmission for off-road EVs.

Both Ford and Toyota have patented manual transmissions for electric vehicles, allowing the driver to control the shift and clutch actuation even if mechanically unnecessary. Stellantis also has a schiff for EV transmissions achieved through a physical shifter or clutch, but not by changing the motor torque