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 in some industrial and commercial equipment and heavy vehicles. The friction clutch is replaced by a fluid clutch, and the system defines a set of gear ranges based on the car’s needs. When you park the vehicle, all gears are locked to prevent the car from rolling 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 either 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 the Automatic Transmission
General Motors and REO both launched 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. GM’s transmission was the first of its kind to use a hydraulically controlled planetary gearbox, allowing gears to be changed based on the vehicle’s travel speed.
The planetary transmission was one of the most recent developments. important on the road to the modern automatic transmission. Although GM was the first to use the version with hydraulic controls, this technology actually dates back to a 1900s invention by Wilson-Pilcher. That innovation consisted of four forward gears in two gears that could be shifted with a single lever.
How an Automatic Transmission Works
The most common type of automatic transmission uses hydraulic power to shift gears According to How Stuff Works, this device combines a torque converter or fluid coupling with gear sets that provide the desired range of gearing for the vehicle. The torque converter connects the engine to the transmission and uses pressurized fluid to transfer power to the gears. This apparatus replaces a manual friction clutch and allows the vehicle to come to a complete stop without stalling.
Information in the Art of Manliness 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 attached central shaft. The power created by this rotation is 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 is positioned 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 run and therefore the vehicle cannot be pushed to start.
The 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 stationary while turning another to transmit engine torque and shift up or down gears.
The different gears are sometimes called sun gear, crown gear, and gear. planetary gear. The arrangement of the gears determines how much power will flow from one gear to another and into the vehicle’s drivetrain when it shifts.
Gears in an Automatic Transmission
The gears in an automatic transmission They include the following:
- According to How a Car Works, when you shift your vehicle into the drive position, 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 speeds, but older cars and entry-level compact cars may still have four or five-speed automatics.
- Third speed locks the transmission in third gear or limited to first, second and third gear ratios. This provides the power and traction needed to go up or down hills or to tow a boat, RV or trailer. When the engine reaches a designated revolutions per minute (RPM) level, most vehicles automatically downshift third gear to prevent engine damage.
- Second gear locks the transmission in second gear or limits it to 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 into this gear to protect the engine at a certain RPM. Like second and third gear, this gear is best used for towing, driving up and down hills, and when traveling in slippery or icy conditions.
Advantages of a Transmission automatic
According to How Stuff Works, 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, as 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 for make the necessary changes. , giving you more focus to focus on the task of driving.
Many drivers also find an automatic transmission easier to control 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 Lead Technician Duane Sayaloune of Your Mechanic. com. For any comments or correction requests, please contact us at [email protected].
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