Automatic gearbox (AT)
An automatic transmission (AT) is a type of transmission that automatically changes gears depending on the speed of the vehicle and the load on the engine. Automatic transmissions usually have from 4 to 8 forward gears and one reverse gear.
Operating principle
An automatic transmission uses a torque converter to transfer torque from the engine to the transmission. The torque converter consists of three elements: pump, turbine and stator. When the engine is running, the pump creates a flow of fluid that drives the turbine. The stator directs fluid flow to the pump, creating a hydrodynamic connection between the engine and transmission.
Gear shifting is accomplished by a hydraulic control module, which uses valves and solenoids to regulate fluid flow through the automatic transmission. The control module is controlled by an electronic control unit (ECU), which receives signals from various sensors such as:
*Car speed sensor
* Engine speed sensor
* Throttle Position Sensor
* Automatic transmission temperature sensor
Types of automatic transmission
There are several types of automatic transmission:
* Classic torque converter automatic transmission is a traditional type of automatic transmission that uses a torque converter to transmit torque.
* CVT is a continuously variable transmission that provides smooth gear shifting without noticeable jerks.
*A robotic manual transmission is a type of automatic transmission that uses an automated clutch and mechanical gears.
Advantages of automatic transmission
* Convenience: Automatic transmission makes driving easier by eliminating the need to change gears manually.
* Smooth: The automatic transmission provides smooth gear shifting, which improves driving comfort.
* Efficiency: Some types of automatic transmission, such as a CVT, can improve a vehicle’s fuel efficiency.
Disadvantages of automatic transmission
*Higher Cost: Automatic transmissions are typically more expensive to produce than manual transmissions.
*Lower Efficiency: The torque converter in an automatic transmission may result in a slight loss of power compared to a manual transmission.
* More complex design: Automatic transmissions have a more complex design, which can lead to a higher risk of breakdowns and maintenance.