How Does an Automatic Transmission Work?

How Does an Automatic Transmission Work?

How Does an Automatic Transmission Work?

How does engine connect to transmission

according to meineke, most cars use a form of automatic transmission called a hydraulic planetary automatic transmission, which is also used in an enlarged version on some industrial and commercial equipment and heavy duty vehicles. the friction clutch is replaced by a fluid coupling and the system defines a set of gear ranges depending on the needs of the car. when you park the vehicle, all gears are locked to prevent the car from moving forward or backward.

A less common option is the automated manual transmission (amt). Sometimes called a semi-automatic transmission, this model pairs the clutches and gears of a manual transmission with a suite of actuators, sensors, processors, and pneumatic systems. AMTs work like an automatic transmission while providing the affordability and fuel economy benefits of a manual transmission. With this type of transmission, the driver can change gear manually or opt for automatic transmission. either way, he or she doesn’t need to use the clutch, which is operated by a hydraulic system.

history of automatic transmission

general motors and reo introduced semi-automatic vehicle transmissions in 1934. these models posed fewer challenges than the traditional manual transmission, but still required the use of a clutch to change gears. The GM transmission was the first of its kind to use a hydraulically controlled planetary gearbox, allowing gears to change based on vehicle travel speed.

The planetary transmission was one of the most important developments on the way to the modern automatic transmission. Although GM was the first to use the version with hydraulic controls, this technology actually dates back to a 1900 Wilson-Pilcher invention. that innovation consisted of four forward gears on two trains that could be shifted with a single lever.

functioning of an automatic transmission

The most common type of automatic transmission uses hydraulic power to change gears. depending on how things work, this device combines a fluidly coupled or torque converter with gear sets that provide the desired gear range for the vehicle. The torque converter connects the engine to the transmission and uses pressurized fluid to transfer power to the gears. this device replaces a manual friction clutch and allows the vehicle to come to a complete stop without stalling.

the art of masculinity information describes the operation of an automatic transmission. As the engine transmits power to the torque converter pump, the pump converts this power into transmission fluid that drives the torque converter turbine. This apparatus increases the power of the fluid and transmits even more power to the turbine, creating a vortex power rotation that spins the turbine and the attached central shaft. the power created by this rotation is then transmitted from the shaft to the transmission’s first set of planetary gears.

This type of transmission has what is called hydraulic control. The transmission fluid is pressurized by an oil pump, which allows the speed to change based on vehicle speed, tire revolutions per minute, and other factors. The gear pump sits between the planetary gear set and the torque converter, where it draws and pressurizes transmission fluid from a sump. the pump inlet leads directly to the torque converter housing connected to the engine flexplate. when the engine is not running, the transmission does not have the necessary oil pressure to operate and therefore the vehicle cannot be started.

Planetary gear train is a mechanical system in which the gears are connected with a set of bands and clutches. when the driver changes gear, the bands hold one gear while turning another to transmit engine torque and shift up and down.

The different gears are sometimes called sun gear, ring gear, and planet gear. Gear arrangement determines how much power will flow from gear to gear and to the vehicle’s drivetrain when you shift.

gears of an automatic transmission

Gears in an automatic transmission include the following:

  • Consistent with how a car works, when you shift your vehicle into drive, you engage all available forward gear ratios. this means the transmission can move through its full range of gears as needed. six-speed automatic transmissions are the most common number of gears, but older cars and entry-level compacts may still have four or five-speed automatics.
  • third gear locks the transmission in third gear or limited to first, second, and third gear ratios. this provides the power and traction needed to go uphill or downhill or to tow a boat, RV or trailer. when the engine reaches a designated level of revolutions per minute (rpm), most vehicles automatically downshift third gear to prevent engine damage.
  • second gear locks the transmission in second or limits it to the first and second gear ratios. this gear is ideal for going up and down hills in slippery conditions, as well as driving on ice, snow, and other types of inclement weather.
  • first gear is used when you want to lock the transmission in first gear, although some vehicles will automatically shift this gear to protect the engine at certain rpm. Like second and third gear, this gear is best used for towing, driving up or down hills, and when traveling in slippery or icy conditions.

advantages of an automatic transmission

The way things work, the biggest advantage of an automatic transmission is the ability to drive without the need for a clutch, as is required with a manual transmission. people with many disabilities can drive using an automatic transmission, since operation requires only two usable limbs.

The lack of a clutch also eliminates the need to pay attention to manual shifts and monitor the tachometer to shift as needed, giving you more attention to focus on the task of driving.

Many drivers also find it easier to control an automatic transmission at low speeds than a manual transmission. the hydraulic automatic transmission creates a phenomenon called slow idle, which encourages the vehicle to move forward even when idling.

Information and research in this article verified by ASE Certified Master Technician Duane Sayaloune of For any feedback or correction request, please contact us at [email protected].


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