Differences Between Automatic and Manual Transmission

Which is better, manual transmission or automatic transmission? This is a very interesting question. This is an old debate that has been going on for the last 70 years. Manual and automatic transmission are completely different technologies using different mechanisms and different principles. One is based on a simple gear wheel, the other on a planetary gear set. One uses a torque converter while the other uses a clutch pack.

How Automatic and Manual Transmission Work :

An internal combustion engine produces useful torque and power only within a certain speed range. Because of this problem of the internal combustion engine, connecting the engine directly to the wheels is not a smart idea. With such an approach, the engine will give very low efficiency. Instead, we need a vehicle that can always keep the engine speed within the maximum efficiency range. The transmission adjusts the speed change of the drive wheels. First, let’s explain how a manual transmission achieves speed change. Manual transmission; It consists of pairs of gears brought together. It consists of three parts. Inlet is the middle shaft And outlet The inlet is connected to the middle shaft. In this way, the middle shaft always rotates at a constant speed. The middle shaft is then connected to the output gear set. You can see that the output gears will turn at different speeds depending on the different gear ratios. But the output gears are not fixed with the output shaft, and you may see a gap between the output gears and the output shaft. If we connect only one output gear to the shaft, the shaft will have the speed of the gear it is connected to. For this purpose, the main shaft gears have a synchronizer cone tooth mechanism. A synchronizer collar is connected to the shaft and a sleeve is slid onto it. Just by moving this sleeve it can connect the gear and shaft together. It may seem simple. However, during real operation, the hub and gear will rotate at different speeds. And the gear sleeve connection will not be possible as seen. First, let’s make their speed the same. For this, we must cut off the power to the transmission. This is where the use of clutch pack comes into play. By disengaging the clutch pack, power to the planetary gear set was removed. Now a friction synchronizer ring can help match the gear speed to the sleeve.

What Does a Synchronizer Ring do?

When there is no force pushing the synchronizer ring against the gear, it helps match the speed of the gear to the hub. Once engaged, the clutch pack is engaged. It disengages the clutch every time you need to change gear. This also means power outage. There is a decrease in speed when changing gear. That’s why manual transmission driving is never smooth.

Difference Between Automatic Transmission and Manual Transmission:

Automatic transmission was developed to overcome the power loss problem in manual transmission and uses a planetary gear set arrangement instead of a simple gear pair. It can be seen that a planetary gear set has two inputs and one output. The basic principle of automatic transmission is simple. Just change these two input speeds and you get different output speeds. This is an interesting mechanism and the simplest automatic transmission possible. Clutch packs were introduced to stop the movement of the ring gears. When the clutch pack is pressed, the corresponding ring gear remains stationary and the carrier rotates. When the first clutch is pressed, the green ring gear stops and we shift to first gear. If we can rotate the green ring from here, the exit velocity will increase. To achieve this, you need to release the first clutch and engage the second clutch. The green ring gear will rotate like the carrier of the second group to which it is connected. The important thing here is; The first clutch is released at the same time that the second clutch is engaged. Therefore, there is no loss in power transmission. Achieving different output speeds is possible with two planetary gear arrangements. By using three planetary gear sets in series, we will be able to obtain six different forward and one reverse speeds. The beauty of automatic transmission is that we can achieve different output speeds with suitable clutch packages. Now let’s directly compare the differences between these two technologies. As discussed in automatic transmission, there is no interruption of power flow so you get a smooth driving experience. Computer-controlled use of the automatic transmission makes driving simpler. It is clear that manual transmission technology is simpler than automatic. It has fewer components and is easier to repair. The automatic transmission is a tightly packaged arrangement. When it comes to heavy duty conditions, manual transmissions offer greater durability. Therefore, almost eighty percent of heavy-duty trucks use manual transmissions. The functioning of automatic and manual transmissions during braking situations is also quite different and interesting from each other. In vehicles with manual transmission, you must fully depress the clutch pedal before pressing the brake pedal. In this way, the rotation of the engine and the rotation of the wheel are completely separated and the sudden cut-off of the wheel is not transferred to the engine. However, an automatic transmission car has no clutch pedal, so a torque converter is used to disconnect the engine rotation from the transmission.

What is Torque Converter Function :

This is a fluid coupling that allows slippage, so a torque converter helps the automatic transmission perform braking without the need for a clutch pedal. However, a torque converter is a good heat generator, which reduces the efficiency of the vehicle. As a result, automatic transmission vehicles tend to be less fuel efficient than manual vehicles. However, modern torque converters have overcome this problem.


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