Just as there are two types of transmissions, there are two types of drivers. There are those who prefer a manual transmission where they’re in charge of shifting gears, and then there are those who enjoy driving as long as the vehicle has an automatic transmission. The latter drivers revel in the fact that there isn’t a clutch and the car changes gears for them, allowing them to focus on the road ahead of them.
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There’s a bit of a misunderstanding in that way of thinking, though, if anyone genuinely believes there is no clutch. The clutch is responsible for engaging and disengaging the wheels from the engine, so the vehicle can stop and keep the engine running. An automatic transmission works with a similar mechanism called the torque converter. This component accomplishes the same thing as a clutch, allowing a car to come to a complete stop while letting the engine run.
That’s not to say there isn’t a clutch of any kind in an automatic transmission. There is a series of slim friction discs within it that are a part of a multi-disc clutch assembly. Today there are a lot of high-end automakers going the automatic route in the form of dual-clutch transmissions (DCTs), which function similarly to an automatic but utilizes two clutches and performs better than a manual transmission.
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How an automatic transmission works
While hardcore drivers might not consider an automatic vehicle something fun to drive, the automatic transmission is an impressive component. There’s a lot happening under the hood when a driver shifts their car into Drive because it isn’t the only time the transmission shifts gears. The transmission has more gears than Drive, Park, Reverse, and Neutral.
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The Drive setting gives the vehicle access to all the forward moving gear ratios. In addition to the torque converter there’s what’s called the planetary gear set, consisting of a ring gear, a sun gear, a planet carrier, and planet pinions. This planetary gear set is what allows a car to shift through gears automatically.
Different parts of the gear set will act as the input gear (generates power) or output gear (receives power), while others can be held static, which is accomplished with the help of brake bands and clutches. Brake bands will tighten onto or loosen the ring or sun gear, depending on which is needed. The clutches are a series of friction discs that can also cause a component in the planetary gear to be an input gear or be stationary. This all happens through a combination of mechanical, hydraulic, and electrical systems to create a seamless time on the road.
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Typically, automatic transmissions are built with multiple planetary gear seats that form the different gear ratios the car will switch to. The moving parts of this system determines which gear ratio the car is in at any given time.
Benefits of an automatic transmission
There will always be manual versus automatic transmission debates, but the fact of the matter is that there are definite benefits to automatic gearboxes. The torque converter in an automatic transmission gives a vehicle better acceleration than a clutch from a complete stop. Newer torque converters can even increase the amount of torque that an engine produces.
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Anyone who dabbles in high-performance racing with an automatic transmission would want to look into a high-stall torque converter. A high-stall torque converter sends power to the wheels at a significantly higher rpm, improving the vehicles overall acceleration. It’s not something useful for everyday drivers who are just picking up kids from school and going to the grocery store.
The biggest benefit to the automatic gearbox is its smooth driving experience. Drivers can simply focus on driving without concerning themselves with pressing in the clutch pedal, shifting gears, releasing the pedal, and then pressing down on the accelerator. While taking a more interactive role while driving might be fun, not everyone is looking for that when they want to get from Point A to Point B.
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