Practically all motor vehicles have a transmission, whether it is automatic or manual. The key functions of the transmission are to pass on the rotation of the engines crankshaft into a more usable rotational speed and to multiply the torque of the engine’s output.
What does a transmission do?
In vehicles, transmissions convert speeds and torques along the drive-train. The objective is to maximize the efficiency of the engine which means to achieve low fuel consumption with the greatest performance or torque and, therefore, driving dynamics.
Difference b/w Manual & Automatic transmission
A manual transmission is also known as a stick-shift, and that says it all the driver uses a stick to change gears. And in a modern car, the shift lever is mounted vertically on the middle console and linked to the transmission via a linkage.
To change gears, a clutch disc sandwiched between the engine and the transmission needs to be released via a third pedal located on the left side of the brake. Release the clutch, select the desired gear, and engage the clutch again. From a standstill, engaging the clutch too slowly will wear out the disc impulsively, and engaging it too quickly will cause the engine to stall.
A traditional automatic is connected to the engine via a hydraulic torque converter. It can change gears without any input from the driver. The process is done hydraulically or electronically by monitoring important parameters such as the position of the throttle pedal, the speed that the car is traveling at, and the engine’s rpm. In many automatic cars, the gears can be selected manually using either the shift lever or paddles mounted behind the steering wheel.
There are many advantages of having only two pedals. It’s nearly impossible to stall the engine with this configuration, and an automatic car tends to be smoother and more comfortable to drive than a stick-shift, particularly in stop-and-go traffic. An automatic usually requires less maintenance than a manual as well, though that can differ from model to model. Finally, a dual-clutch automatic gearbox often shifts gears in milliseconds for greater performance and efficiency.
The CVT offers a similar driving experience to an automatic, but function using an entirely different mechanism. In fact, the CVT doesn’t have gears. Instead, it uses a system of belts and pulleys to generate an infinite range of ratios. The car’s computer decides how to adjust the pulleys to create the optimal ratio for the meticulous driving situation. This makes the CVT’s primary advantage: fuel economy. No other transmission type can propose more MPGs than a CVT.
Semi-automatic and dual-clutch transmissions
A semi-automatic uses a similar mechanical layout to a conventional transmission, but uses a system of pneumatics and actuators to change gears. In a Dual-Clutch Transmission (DCT), there are two separate clutches for both odd and even gears, which allows for extremely fast shifts. These gearboxes can normally be operated in a fully automatic mode, or manually shifted via paddles on the steering wheel.