Car Transmission Automatic Shift
What is an automatic shift transmission?
An automatic shift transmission (AST) is a type of car transmission that automatically changes gears without the need for driver input. This is in contrast to a manual transmission, which requires the driver to manually select the gear they want to be in.
ASTs are typically found in newer cars, and they offer a number of advantages over manual transmissions, including:
- Easier to drive: ASTs are much easier to drive than manual transmissions, as the driver does not need to worry about shifting gears.
- More fuel-efficient: ASTs can be more fuel-efficient than manual transmissions, as they can automatically select the most efficient gear for the current driving conditions.
- More comfortable: ASTs can be more comfortable to drive than manual transmissions, as the driver does not need to constantly shift gears.
How does an automatic shift transmission work?
ASTs use a variety of sensors to determine the current driving conditions, and they use this information to select the most appropriate gear. These sensors include:
- Speed sensor: This sensor measures the speed of the car.
- Engine speed sensor: This sensor measures the speed of the engine.
- Throttle position sensor: This sensor measures the position of the gas pedal.
- Brake pedal switch: This switch detects when the brake pedal is depressed.
The AST uses the information from these sensors to determine the following:
- The current gear
- The desired gear
- The shift point
The shift point is the speed at which the AST will shift into the next gear. The shift point is determined by a number of factors, including the car’s speed, the engine speed, and the throttle position.
Once the AST has determined the shift point, it will shift into the next gear. The shift is made by a series of clutches and gears. The clutches engage and disengage the gears, and the gears change the speed of the output shaft.
Types of automatic shift transmissions
There are two main types of ASTs: planetary gearsets and continuously variable transmissions (CVTs).
Planetary gearsets
Planetary gearsets use a series of gears to change the speed of the output shaft. The gears are arranged in a planetary configuration, with the sun gear in the center and the planet gears orbiting around it. The ring gear is connected to the output shaft.
When the sun gear rotates, it causes the planet gears to rotate around it. This rotation causes the ring gear to rotate, which in turn changes the speed of the output shaft.
Continuously variable transmissions (CVTs)
CVTs use a system of pulleys and belts to change the speed of the output shaft. The pulleys are connected to the input shaft and the output shaft, and the belts are wrapped around the pulleys.
When the input shaft rotates, it causes the pulleys to rotate. The rotation of the pulleys changes the tension on the belts, which in turn changes the speed of the output shaft.
Advantages and disadvantages of automatic shift transmissions
ASTs offer a number of advantages over manual transmissions, including:
- Easier to drive
- More fuel-efficient
- More comfortable to drive
However, ASTs also have some disadvantages, including:
- More expensive to purchase and maintain
- Less responsive than manual transmissions
- May not be suitable for all driving conditions
Conclusion
ASTs offer a number of advantages over manual transmissions, and they are becoming increasingly popular in new cars. However, it is important to weigh the advantages and disadvantages of ASTs before deciding if they are right for you.
