Future Automatic Transmission Requirements

摘要

So far engine downsizing in passenger cars has been used to increase the vehicle performance and to compensate the vehicle weight increase. In the future the continuing downsizing trend on the engine side will be used to maintain today's performance level and further reduce the fuel consumption. To maintain launch performance and at the same time exploit the engine potential a (torque) ratio spread of up to 10 and launch ratio of up to 20 will be necessary. The future automatic transmission will be the enabler to exploit the potential of these extreme downsized vehicles. Today's planetary automatic transmissions with up to 8 gears and torque amplification during launch (converter) are already close to this target. For DCT transmissions new gear set approaches will become necessary to realize the demanded ratio spread with acceptable mechanical complexity. With the X-DCT FEV shows such a DCT transmission concept. The X-DCT has a forward gears and a ratio spread of about 10.3 with a mechanical complexity comparable to a conventional 6 or 7 speed DCT.