FEV is exhibiting a new transmission specially designed for plug-in hybrid powertrains at this week’s SAE World Congress in Detroit.
According to FEV, engine downsizing for increased fuel efficiency has led to challenges for transmission developers, who must provide higher levels of capability in a smaller package. The company took a “clean sheet approach” to develop a transmission that meets these requirements.
The new transmission’s capabilities include two-speed pure electric driving mode, use as an ICE range extender in parallel mode, and a flexible eCVT (power split) mode. The transmission does not use a torque converter, and includes only one electric machine.
FEV says its new tranny is 10 percent lighter, shorter and less costly to manufacture than a similar dual-clutch transmission. It is designed to be package-neutral and robust with a low level of complexity.
FEV’s design process incorporated TCU software that was developed in-house; calibration was optimized using the company’s proprietary TOPexpert tool chain. Testing included putting the transmission through FEV’s extreme “Nurburgring” test cycle for sports car performance.
Features of the new transmission include:
- Electric drive mode with two ratios
- Full hybrid functionality including e-boost and regen
- Creep behavior similar to conventional automatic transmissions
- High fuel economy enabled by elimination of torque converter and a highly efficient parallel mode of operation