Automobile Transmission System - Types And Operations

The transmission system refers to the mechanism that transmits the power developed by the engine to the wheels of an automobile in the form of kinetic energy. A basic transmission system comprises various transmission components such as gears, shafts, and other parts, which function together to enable the movement of an automobile.

Often, a transmission has multiple gear ratios (or simply "gears"), with the ability to switch between them to speed varies. This switching may be done

  1. manually (by the operator), or automatically.
  2. Directional (forward and reverse) control may also be provided.
  3. Single-ratio transmissions also exist, which simply change the speed and torque (and sometimes direction) of motor output.

In motor vehicles, the transmission generally is connected to the engine crankshaft via a flywheel and/or clutch and/or fluid coupling, partly because internal combustion engines cannot run below a particular speed.

The output of the transmission is transmitted via driveshaft to one or more differentials, which in turn, drive the wheels. While a differential may also provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds (essential to avoid wheel slippage on turns) as it changes the direction of rotation.

The most common transmission systems that have been used for the automotive industry are

  1. Manual transmission,
  2. Automatic transmission,
  3. Semi-automatic transmission, and
  4. Continuously-variable transmission (CVT).

Manual Transmission

The first transmission invented was the manual transmission system. The driver drives the vehicle with the help of a hand-operated gearshift and a foot-operated clutch. He needs to disengage the clutch to disconnect the power from the engine first, select the target gear, and engage the clutch again to perform the gear change. This will challenge a new driver. It always takes time for a new driver to get used to this skill.

Automatic Transmission

An automatic transmission is that type of transmission that automatically changes the gears with regard to speed of the vehicle. The primary components of automatic transmission include planetary gear sets, hydraulic system, seals and gaskets, torque converter, governor, modulator and computer. It uses a fluid-coupling torque converter to replace the clutch to avoid engaging/disengaging clutch during gear change. A completed gear set, called planetary gears, is used to perform gear ratio change instead of selecting gear manually. With the invention of the automatic transmission, a driver no longer needs to worry about gear selection during driving. It makes driving a car much easier, especially for a disabled or new driver. However, the indirect gear contact of the torque converter causes power loss during power transmission, and the complicated planetary gear structure makes the transmission heavy and easily broken.

The other auto transmission parts used in automobile transmission system are flywheel, flywheel ring gears, and pressure plate.

Semi-automatic Transmission

A semi-automatic transmission tries to combine the advantages of the manual and automatic transmission systems, but avoid their disadvantages. However, the complicated design of the semi-automatic transmission is still under development, and the price is not cheap. It is only used for some luxury or sports cars currently.

Continuously-Variable Transmission (CVT).

CVT has been used for low-powered machinery like scooters for a long time due to its highly efficient gear change. However, it is a challenge to install it on high power machinery because of the strength of the driving belt. With the progress of materials technology, engineers have been successfully installed on automobiles, making the power transmission efficiency.

Gear and gear parts constitute an essential part of an automotive transmission system. These transmission parts are toothed wheels that comprises of an interlinked set of rotating gears that are basically used for changing the speed or direction of a moving vehicle. The size and dimension of the automotive gears differ according to the size of the vehicle. For covering smaller distances there are low gears and for larger distances, there are high gears. High gears usually have more number of teeth and have an ability to cover larger distances in just one revolution of pedal.

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