Images of a BMW patent filing for a seven-speed manual transmission have been discovered revealing a system that incorporates a clutch and a manual shift and allows for at least seven forward gears to be selected from.
According to Bimmerpost, the new transmission addresses the problem of having greater than six gears in an H-pattern-style gearbox - an increased risk of accidental mechanical damage and user practicality - by providing a system that allows for a manually shifted gear lever but one that only allows the driver to select the correct gear at the correct time.
The design does this through surrounding the shift gate with a magnetorheologic or electrorheologic fluid that works hand-in-hand with a sensor-based computerised shifting module that calculates the gears that are appropriate to select from and the gears that aren't based on the driving situation. The fluid's viscosity would then be altered via magnetic field or electric voltage to physically block the engagement of incorrect gears. This means the system will not allow, for example, shifting into first gear when travelling at 100km/h.
Bimmerpost reports the patent indicates two different approaches to implementing the system: a traditional manual transmission that requires the use of a clutch pedal to shift gears, potentially up to eight, and a clutchless shift-by-wire arrangement that would link a manually shifted gear lever to an automated sequential manual gearbox or SMG.