Proterra plans to use an EV transmission made by power management company Eaton’s eMobility business.

Eaton’s 4-speed medium-duty transmission will be installed in ProDrive—a Proterra drivetrain used in its ZX5 electric transit buses. The company says the transmission has “electric gearshift actuation that enables manufacturers to use smaller, more efficient motors.”

“Our 4-speed transmission provides uncompromised launch-ability on grade and has shift points to keep the electric motor operating in its most efficient region while drivability and vehicle safety is taken into account,” said Julie Marshaus, Eaton’s Manager of New Product Introductions, ePowertrain.

The transmission is composed of a lightweight countershaft gearbox offering a torque capacity up to 1,200 Nm (885 lb-ft). Eaton says its helical gears “ensure smooth, low-noise operation and a shifting strategy designed to extend range and battery life.”

According to Eaton, “Road tests have shown a 20%­ to 30% efficiency improvement in energy consumption under normal driving conditions compared with a direct-drive transmission, and a 10% to 15% improvement compared with a current 2-speed solution.”

Source: Eaton