Seven-Speed Hybrid AMT Shown at SAE World Congress in Detroit
Aachen-based engineering consultancy FEV has used the annual SAE World Congress in Detroit to show a prototype automated manual transmission for transverse-engine, front-wheel drive cars.
The seven-speed unit incorporates an electric motor to enable the vehicle to operate as a hybrid and to supply torque in-fill to improve comfort during gearshifts. Sluggish and jerky gearshifts have been a frequent complaint from users of first- and second-generation AMTs already on the European market. As a result, sales of AMT-equipped models, both family-oriented and sporting, have been disappointing.
The internally-developed transmission, designated 7H-AMT, has a torque capacity of 320 Nm and an axial length of just 356 mm, allowing it to be packaged in a similar space to a six-speed manual of the same torque handling capability. The single electric 35 kW motor is mounted above the main casing and provides a second torque path through the gearbox for hybrid traction. The motor is also responsible for engine stop-start, energy recuperation under braking and torque support to boost the combustion engine under hard acceleration. A single dry clutch between the combustion engine and the transmission is locked open to decouple the engine during EV operation.
The arrangement also allows for the combustion engine to recharge the traction batteries during normal driving.
The motor can be specified in various power ratings to allow the transmission to be configured as a micro hybrid (stop-start plus intelligent battery charging), a mild hybrid or a full hybrid capable of electric-only operation. The motor also incorporates a magnetic clutch to a conventional air conditioning compressor to allow uninterrupted climate control while the engine is shut down in EV or stop-start mode. Engineers said this was a much more cost-effective solution than to use a bespoke electrically-powered compressor. FEV has not commented on the likely cost position of the 7H-AMT, nor has it disclosed any production plans or discussions with potential automaker customers for the design.
Story Filed: 10/02/2010
By Tony Lewin, managing editor DCTfacts.com