What is the best transmission for a car?

Hi everyone! I´m back for another post. Today we are going to talk about transmissions. Nowadays you can buy al sorts of fancy gearboxes for cars, but which one of those is best?
Before I explain which is best, I must briefly explain what a transmission is.

A transmission is a device which has an input from a motor or engine, and transmits its power and torque to the desired location (the wheels of a car) through an output. But the transmision does more than that. It will also change the RPMs of the output of the engine to increase efficiency. Why is all this complicated stuff necesary? Here´s why:

Imagine a car with a piston engine but with no transmission. The crankshaft of the engine is directly connected to the wheels. The car will move, but there is a problem. The engine will transmit all of its power and torque to the wheels, but the engine and wheels will spin at the same time, so 1:1 ratio.
This is a problem because once the car reaches the maximum RPM it can handle, it will no longer be able to accelerate, because the ratio is insufficient. The wheels won´t be able to spin faster because the engine can no longer rev more without exploding! The solution to this is a transmission. The transmission will take the power and torque of the engine, and allow the wheels to spin faster or slower than the engine, depending on the situation.
This cool tech increases the efficiency of the device that spins the transmission, because it´s more efficient at doing the work that it has to do. This device is used in a wide variety of applications, like in ships, power plants, cars, and even newer jet engines! Today we will only talk about car transmissions.

What different types of car transmission are there?

1. The manual gearbox: the favourite among certain car enthusiasts(purists), the manual transmission is the first transmission to be widely used in automobiles, and is still popular today, although in decline.

Animation of a manual transmission in use.

Manual transmissions are called like so because everything must be done by the driver of the vehicle. For a manual transmission(or most transmissions with clutches) to change gear, a few steps are necesary:

1º: disengage the engine from the transmission. This is done by operating the clutch, a device that is connected to both the transmission and engine, but is made up of plates that seperate, disengaging the engine from the transmission. These plates are also tough because, when changing gear, there will be discrepancies in the speed between the engine and gearbox, so lots of friction and heat will be produced.

2º. Select the desired gear. This is done through the gear selector, which is operated by hand. This movement of the gear selector, which can be seen on the gif, selects the gear, so it is now ready to be spun by the engine.

3º Remove the clutch(gently!) and you can continue driving in that new gear.

BTW: Some older sports cars had automatic transmissions which were  automated manual transmissions.

2. Automatic transmissions.

This is made up of many transmissions. Here are the most popular designs:

Hydraulic auomatic transmission: this gearbox is very popular and effective at doing what it does. It´s gears are aranged in a planetary gear set. Instead of using a human controlled clutch which transmits its power too quickly sometimes, as well as not being consistently smooth; it uses a hydraulic coupling, also known as a torque converter to transmit the power from the engine to the gearbox smoothly. That´s why these transmissions are also known as "torque converters".

A modern automatic transmission

Dual Clutch Transmissions(DCT): these transmissions don´t use planetary gear sets, rather, they use the best of manuals and the best of torque converters. They have a very similar layout to the manual transmission. A DCT can be described as two manuals in one, where the two clutches are actuated automatically. The DCT is fast at changing gears because, when the car has to change gear, there is an engaged clutch and its corresponding shaft with gears that´s being used by the engine, while the other shaft with gears has the necesary gear selected, and the electronically actuated clutch is fast and smooth at changing. So one shaft switches to another with a different gear. 

Animation of a DCT

Continuously Variable Transmission(CVT): this is the most peculiar transmission of the bunch. It doesn´t have gears, but it changes the RPM of the engine for the wheels through a pulley system. The movement of this pulley system takes the place of traditional gear ratios.

Which transmission is best? In terms of driving pleasure, I cannot say because it´s a subjective matter and I can´t drive as of yet! In terms of engineering, there is no clear victor, though manual transmissions are an old technology which will eventually be retired. Automatic transmissions like the ones described earlier will also be used in certain electric cars, though electric cars don´t necesarily need transmissions.

I hope you enjoyed this post! I am not an enginner, rather I pretend being one, so I could have made a mistake! 

Bye!