The conventional wisdom on battery-electric vehicles is that electric motors produce instant torque, making transmissions unnecessary. However, this assumption breaks down when vehicle weight and vocational demands increase.
In heavy-duty trucking, transmissions are no longer a luxury but a requirement, according to Sigma Powertrain CEO John Kimes. The company's technology allows for smaller motors, improved efficiency, and increased gradeability.
Sigma Powertrain is developing multi-speed electric transmissions specifically for commercial, vocational, and off-highway vehicles. This approach addresses the inefficiencies of single-speed transmissions in these applications.
The current single-speed reduction gearbox systems force motors to operate far outside their peak efficiency range, resulting in wasted energy and larger battery packs. Sigma's technology mitigates this issue by keeping the electric motor operating closer to its optimal efficiency range.
Commercial trucks are a different story from passenger vehicles. The demands of heavy-duty trucking require more complex transmission solutions. Sigma's multi-speed transmissions address these challenges.
The company offers three transmission families: MID-Series for Class 1-7 trucks, EMAX for Class 6-8 vocational applications, and Terramax for large mining and off-highway equipment. These transmissions improve acceleration, gradeability, and overall efficiency.
Sigma Powertrain's technology is rooted in the company's founder's background in powertrain engineering at Ford and General Motors. The traditional automatic transmission's hydraulic system, torque converter, and friction clutch create significant parasitic energy losses.
Battery-electric trucks cannot afford these inefficiencies due to their limited battery energy density compared to diesel fuel. Sigma Powertrain's multi-speed transmissions solve this problem by reducing energy losses and increasing efficiency.
The largest Terramax configuration scales up to 2.6 megawatts for 400-ton mining trucks, demonstrating the company's ability to adapt its technology to heavy-duty applications.
Sigma Powertrain's technology addresses the limitations of single-speed transmissions in commercial vehicles.
