Probably many of you have not heard of the Sensonic transmission, developed by Saab. The Sensonic system uses electronics to automatically operate the clutch when needed.
It is a normal type clutch with hydraulics linking it to a motor which takes the place of a pedal. The gearbox, with the exception of some added sensors, is again standard manual.
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Saab Sensonic – innovative, but unconvincing on the market
Unfortunately, although this system has significant advantages, the Sensonic system did not come to market acceptance (saab sensonic parking problem), so it was quickly shut down. however, how the system works in practice, we can see in the special episoede of known UK TV show “Top GEAR” from 1997. watch the show and make sure this system works in practice:
1993 Saab has chosen to revive the automatic clutch with a new product made by Fichtel & Sachs. Used by dozens of makes before automatic transmissions were available, clutch control was usually electric or vacuum. With this solution, a microprocessor drives an electric motor that, in turn, operates a clutch master cylinder.
Saab Sensonic transmission from the driver’s angle
The Sensonic version, which was only available with a turbo engine, had a gear lever just like a regular car with manual transmission, but no clutch pedal (electronics did this part of the job), which could control the clutch faster than a human driver.
When the operator touches the gear lever, a computer-controlled actuator operates the clutch. When the car is in gear but stationary, the clutch is only released if the accelerator pedal is depressed. If neither the brake nor accelerator pedal is depressed, a warning tone sounds and a warning is displayed on the trip computer. If no further action is taken within 7 seconds, the engine will stop automatically.
Called “Sensonic“, the automatic clutch is smooth and engeges without any slip. In that time, Saab claimed the clutch will allow better car control and then hoped to appeal to sporting drivers stuck in traffic. The automatic clutch was available as an option in vehicles with 2.0 Turbo engines.
The Saab Sensonic solution has gone down in history
Although quite innovative and usable, this system was quite complex, and any complexity leads to more difficult maintenance. In other words, the solution could not then be described as “hassle-free”, and SAAB, as many already know, also quickly abandoned this innovative gearbox concept.
Similar to the classic automatic transmission, with the Saab Sensonic solution you have shifted the selector lever to neutral when stopping and standing still, so if you have to wait a long time you won’t have to sit with your foot on the brake pedal. The car “crawls” at idle when in Drive mode. According to those who drove the Saab with the Sensonic transmission every day, its kick-down function during overtaking works great and is by no means worse when shifting to a lower gear when overtaking.
Again, according to a longtime owner of a Saab 900 NG model with a Sensonic transmission, this car has been with him for over 25 years, and he never have any problems, without any bad sound from the gearbox or malfunction.
I used to have NG900 Turbo Sensonic 1997.
Brilliant car as long as you didn’t tune it.
After putting stage 3 tuning kit to it (245 hp, 350 Nm) the clutch couldn’t take it anymore and I had to replace with manual clutch and Viggen’s clutch cover.
I had one and it was great until a rubber seal degraded and the oill killed the electrical side of the gizmo. Mine also had a disturbing tendency to creep forward sometimes.
Had one many years ago, hands down the best saab driving experience I ever had when it worked, unfortunately had to convert it back to manual.