Many types of transmission
systems are available in the car market. Like MT, AT, AMT, DCT, etc., and all
of these create confusion. Which system is the best, which is more reliable,
whose performance is good, and whose maintenance is the cheapest? In this
article, we will clear this confusion and learn about the basic working of all
transmissions. We will also see their advantages and disadvantages. And
finally, we will compare all transmissions with the help of a table. Based on
their complexity, cost, maintenance, reliability, and performance.
The Two
Main Types
Transmission systems are
mainly of two types: manual and automatic. Manual is simple; you change gears
by pressing the clutch. But inside automatic, many types of transmissions come.
Like AT, AMT, CVT, DCT.
Manual
Transmission (MT)
This transmission does not
need an introduction. This is the oldest transmission system, which was
invented by a French inventor in 1880. In manual transmission, there is a
gearbox inside which gears of different sizes are fitted. One is the clutch,
which links the engine with the gears. And one is the clutch pedal, with the
help of which you engage and disengage the clutch.
In manual transmission, you
press the clutch pedal, which disengages the clutch. Then you change gears with
the help of the gear lever and release the clutch back. And in this way, gears
shift in a manual transmission. In manual transmission, you have to match the
RPM of the engine and gearbox at the time of gear shifting. Otherwise, a jerk
is felt. Along with this, new drivers also face problems driving uphill.
But in this, all controls
are with you. Because of which you stay more connected to the car, and for this
reason, many people prefer driving a manual car. But in traffic conditions, you
have to shift gears repeatedly. And for those who drive in slow traffic daily,
it becomes quite irritating.
Automatic
Transmission (AT)
To solve these problems,
automatic transmission was made, which you also know as AT. This was the first
true automatic transmission system. There is no clutch pedal in this
transmission system because it has a torque converter instead of a clutch,
which is a fluid-based coupling.
There are mainly two parts
in this torque converter. One is a pump that stays connected to the engine, and
one is a turbine that stays connected to the gearbox. When the engine's
crankshaft rotates, it also rotates the pump. Then the fluid rotates the
turbine with the pump's pressure, and the power reaches the gearbox. Its
gearbox is also not like a manual gearbox. It has a planetary gear system, and
a mechatronic system shifts the gears according to the speed.
The torque converter gets
you rid of the clutch pedal, but it does not transfer power as efficiently as a
clutch. Which affects the fuel economy. The upfront cost of automatic
transmission is also higher, and the maintenance is also higher.
CVT: Continuously
Variable Transmission
After this, around 1958,
CVT arrived. CVT means continuously variable transmission. Continuous because
here the gear ratio keeps changing continuously. This is a system of pulleys
and a belt. One side of these pulleys is movable. Meaning the width of the
pulley can be increased or decreased. With its help, the diameter of the pulley
is changed according to the speed. Through which the gear ratio is manipulated.
The design of a CVT is much
simpler than a traditional automatic transmission. Due to the absence of gears,
a smooth ride is obtained, and fuel efficiency is also good. But in CVT, you
feel a rubber band effect at the time of acceleration. Meaning when you
accelerate, the engine's RPM increases, but the car does not move as quickly.
There is a delay. This delay is called the rubber band effect. Besides this,
being a belt-pulley system, CVT cannot handle torque equal to gears.
DCT: Dual
Clutch Transmission
In 1980, DCT arrived,
meaning dual clutch transmission. As its name says, it has two clutches.
Basically, it has two manual gearboxes. One gearbox has even-numbered gears
like two, four, and six, and the other gearbox has one, three, and five. There
are two separate clutches to engage these two gearboxes.
In a DCT, if the car is
running in first gear, the computer pre-engages the second gear in advance. And
when the second gear needs to be engaged, only one clutch disengages and the
other clutch engages. This results in instant shifting. Understand it like this:
when first gear is active in gearbox A, then second gear is pre-active in
gearbox B. When second gear is active, third gear is pre-active. All this is
managed by the car's TCU, i.e., Transmission Control Unit.
DCT solves two problems of
a normal gearbox. First, of engaging and disengaging the clutch, and second, of
the delay occurring in gear shifting. In DCT, power loss is very low, and
shifting is very fast. Due to efficient gear timing and direct clutch
engagement, fuel economy improves. That is why DCT is preferred in sports cars
and performance vehicles.
But at low speeds, DCT has
a slightly jerky behavior. And DCT has two clutches. So it means more parts,
and more parts means more maintenance and more cost.
AMT: Automated
Manual Transmission
After this comes AMT. AMT
means Automated Manual Transmission. Around 1997, Ferrari started using it in
its production cars. This is basically a manual transmission in which you do
not have to shift gears. A computer does this work for you. Where in other
automatic transmissions, planetary gears are used or a belt or dual clutch is
used, nothing like that happens here. This is like a simple manual transmission
system. Just that it doesn't have a clutch pedal, which gives you freedom from
repeated gear shifting in traffic.
Being simple, it is
cost-effective and easy to maintain. And along with that, good efficiency is
also obtained. But in AMT, gear shifting is not as smooth as other automatics.
Jerks are felt in gear shifting, and there is also a delay in shifting. You can
feel this delay at the time of overtaking. Due to all these reasons, AMT is
mainly used in budget cars.
iMT: Intelligent
Manual Transmission
iMT transmission is the
latest technology. iMT means Intelligent Manual Transmission. Meaning here
there is also a manual gearbox, a gear lever is also there, but there is no
clutch pedal. So, you shift gears according to yourself, but the computer
engages and disengages the clutch for you. So, this is not a pure automatic
transmission. This is a semi-automatic transmission.
Here too, there are the
same advantages and disadvantages that are with an AMT. Gear shifting is not as
smooth as other automatics. There is a bit of lag in gear shifting. Meanwhile,
due to the absence of a clutch pedal, comfort is obtained in traffic. And fuel
efficiency equal to a manual transmission is obtained. Being simple like manual
transmission, it is cheaper and easier to maintain than other automatics. But
you will see this only in limited cars for now.
Comparison
of All Transmissions
Now let's compare all these
transmissions with the help of a table. So that you can understand the
differences between them even better.
The cost of manual
transmission is low. Complexity is also low. Maintenance is also low and
reliability is high. Performance depends on the driver.
The cost of AMT is less
than other automatics. Complexity is also less compared to other automatics.
For this reason, maintenance is also less than them. Reliability is also found
to be okay. Talking about performance, in this you will get to see average
performance compared to other automatics.
iMT is almost like AMT.
Just here the performance you get to see is a bit like manual.
The cost of CVT is higher
compared to AMT and iMT. Complexity is also higher and maintenance is also
higher. Being a belt and pulley system, there are chances of the belt wearing
out. That is why CVT is considered less reliable compared to other transmission
systems. Talking about performance, you get to see smooth performance here. But
it is lazy due to the rubber band effect.
Automatic transmission
which comes with a torque converter: its cost is quite high and because it
comes with a torque converter, its maintenance is also high. It is also average
in terms of reliability. And talking about performance, you get a smooth
performance, but in that, you get to see a little lag.
The cost of DCT is quite
high. Due to having two clutch plates, complexity is also quite high. And if
there is complexity, then maintenance will also be higher. In terms of
reliability, DCT is not as reliable as other transmissions. But talking about
performance, you get to see the best performance in this: quick and sporty.
Wrapping
Up
So this was everything
about different transmissions. Which transmission do you like best and which
transmission will you choose for your next car? Do tell in the comment section.
If you have any questions, you can also ask those in the comment section.
And if you want to
understand the working of manual transmission deeply, a separate article is
already available on the website. We meet in the next article with some such
interesting topic. Until then, keep learning and have a safe drive.
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