Comparison To Other Automated Transmissions
The automatic transmission is fully automatic and one does not need to change gears at all, which happens at the discretion of the computer in the car whereas in the semi-automatic transmission one can up-shift or down-shift without pressing the clutch. The gear can be engaged in manual mode wherein one can move it up and down to change the gears or one could operate the paddle shifters, just behind the steering wheel to perform the same operation. Many modern automated transmissions can also operate in the same manner as a conventional type of automatic transmission by allowing the transmission's computer to automatically change gear if, for example, the driver were redlining the engine. The ability to shift gears manually, often via paddle shifters, can also be found on certain automatic transmissions (manumatics such as Tiptronic) and continuous variable transmissions (CVTs) (such as Lineartronic).
Despite superficial similarity to other automated transmissions, automated transmissions differ significantly in internal operation and driver's "feel" from manumatics and CVTs. A manumatic, like a standard automatic transmission, uses a torque converter instead of clutch to manage the link between the transmission and the engine, while a CVT uses a belt instead of a fixed number of gears. A semi-automatic transmission offers a more direct connection between the engine and wheels than a manumatic and is preferred in high performance driving applications, while a manumatic is often preferred for street use because its fluid coupling makes it easier for the transmission to consistently perform smooth shifts, and CVTs are generally found in gasoline-electric hybrid engine applications.
Typically semi-automatic transmissions are more expensive than manumatics and CVTs, for instance BMW's 7-speed Double Clutch Transmission is a $3900 CAD upgrade to the standard 6-speed manual, while the 6-speed Steptronic Automatic was only a $1600 CAD option. In a given market, very few models have two choices of automated transmission; for instance the BMW 645Ci/650i (E63/64) (standard 6-speed manual) had an optional 6-speed automatic "Steptronic" or 7-speed Getrag SMG III single-clutch semi-automatic transmission until after the 2008 model year, when the SMG III was dropped. Many sport luxury manufacturers such as BMW offer the manumatic for their mainstream lineup (such as the BMW 328i and BMW 535i) and the semi-automatic for their high-performance models (the BMW M3 and BMW M5).
The automated transmission may be derived from a conventional automatic; for instance Mercedes-Benz's AMG Speedshift MCT automated transmission is based on the 7G-Tronic manumatic, however the latter's torque converter has been replaced with a wet, multi-plate launch clutch. Other automated transmissions have their roots in a conventional manual; the SMG II drivelogic (found in the BMW M3 (E46) is a Getrag 6-speed manual transmission, but with an electrohydraulically actuated clutch pedal, similar to an Formula One style transmission. The most common type of semi-automatic transmission in recent years has been the dual clutch type, since single-clutch types such as the SMG III have been criticized for their general lack of smoothness in everyday driving (although being responsive at the track).
Read more about this topic: Semi-automatic Transmission
Famous quotes containing the words comparison to other, comparison and/or automated:
“It is very important not to become hard. The artist must always have one skin too few in comparison to other people, so you feel the slightest wind.”
—Shusha Guppy (b. 1938)
“Envy and jealousy are the private parts of the human soul. Perhaps the comparison can be extended.”
—Friedrich Nietzsche (1844–1900)
“Nature is a self-made machine, more perfectly automated than any automated machine. To create something in the image of nature is to create a machine, and it was by learning the inner working of nature that man became a builder of machines.”
—Eric Hoffer (1902–1983)