Something I have pondered, instead of redesigning the transmission with a torque converter and planetary gear set and bands, why not just use a standard transmission and external to the transmission have the manual controls automated? Shifts and clutch by solenoid along with a throttle actuator for the shift points?
If you go down the road of, “Let’s make design changes to a manual transmission so that it shifts automatically,” you’ll eventually end up with today’s automatic transmission after many iterations.
Every design detail of a modern, automatic transmission is there for a reason.
You can and they sell them. Though a good transmission like a sequential transmission or dual-clutch transmission or, let’s face it, any type of automation is going to cost from some to a lot more than a manual transmission.
Then turn it around: Why don’t manual transmissions incorporate all of the other features of automatics?
Generally because automatic transmissions have always been a weak point, from less power, less efficient,to today’s less durable, and always heavier.
Back in the 50’s my folks were considering a Renault Dauphine automobile. It had a Ferlac clutch. Once you were in gear, you could shift into higher or lower gears without the clutch pedal. When you moved the shifter, a solenoid would disengage the clutch. When you released the shifter, the clutch would re-engage.
The torque converter allows power to be delivered to the wheels at low speeds or even while stopped. With a manual, this is done by the driver slipping the clutch. With practice, a manual driver can do this while doing very little wear to the clutch.
If the clutch itself is automated, it seems it would be difficult to synchronize this with the driver’s needs when starting from a standstill.
‘Automatic’ manuals are common.
The cheapest car with a DCT is probably the Volkswagen Jetta GLI. They are very common in higher end sports cars like Porsche, Audi and Mercedes AMG.
These exist.
They combine the mechanical efficiency of a conventional manual gearbox with the brainpower of a computer that selects whichever gear ratio delivers the best overall powertrain efficiency at any given moment.
The disadvantages are that they exhibit the same harsh/rigid driveline behavior as a conventional manual transmission, and the interruptions of power flow that come with each upshift or downshift. That’s a turnoff for a lot of passenger car owners, but the whole package deal - best efficiency, reduced operator workload - is pretty attractive for professional truck operators.
For passenger cars - especially high-performance sportscars - dual-clutch transmissions seem to be the cat’s meow. They provide mechanical efficiency comparable to a conventional single-clutch gearbox, but the time required to complete a shift is less.
As the FQ has been answered - they do exist - the drawbacks should be fairly well obvious. Very early pre-microprocessor attempts were limited in scope and not that great. It really is a technology that requires integrated circuits. The first road cars that showed up with automated manuals in the early 2000s were pretty bad – expensive, harsh, and unreliable. The early Aston Martin models with the single clutch “F1 inspired” automated manual currently sell for something like half of their manual transmission counterparts, if that, because they’re just straight up garbage.
Modern DCTs are very good in terms of drivability and reliability but they’re still more expensive than a TC automatic. The EV is going to kill torque converters before DCTs ever get a chance to.
Yeah, when the notion of automatic transmissions first came about, the technology capabilities were not there to really do an adequate auto-shifting-manual. It thus took a different evolutionary path.
Today’s high tech automatics can surpass manuals on economy and performance just because a computer can go through 10 gears more effectively than some human brain, arm and leg can go through five. But that makes them still even more complex and expensive.
Also, if you look at the US auto market nowadays, a large proportion of light ICE vehicles come with no choice but a Continuously Variable Transmission as opposed to either a geared automatic or a manual.
Thank you all for the replies, it seems to cover the reasons pretty well.
As a teenager, I inherited my grandfather’s 1952 DeSoto with ‘Fluid Drive’ providing the option to shift gears either manually or automatically. This concept by the automaker may have designed to appeal to both sexes as a marketing tool.