A semi-automatic transmission (also known as clutch less manual transmission, automated manual transmission, flappy-paddle gearbox, or paddle shift gearbox) is a system which uses electronic sensors, processors and actuators to execute gearshifts on the command of the driver. This removes the need for a clutch pedal which the driver otherwise needs to depress before making a gear change, since the clutch itself is actuated by electronic equipment which can synchronise the timing and torque required to make gear shifts quick and smooth.

The top advantage of this type of system is that a semi automatic transmission and gearbox facilitates better fuel efficiency, as you might find as a benefit on a manual gearbox and manual car. In addition, it is easy to use and more efficient than a manual car, since the clutch is not involved.

Working:

A semi automatic transmission uses different types of energy to propel the car and switch the gears effectively. It uses kinetic energy to turn the wheels through the input shaft and the gears, letting it glide smoothly on the outdoor terrain. In addition, there is a clutch mechanism located between the engine and the semi-automatic gearbox that allows the gearbox to engage or disengage.

The timing of the gearbox in the semi automatic transmission to engage or disengage depends on the situation. It will engage when the engine tells it to and disengage when it can spin without the engine having to interfere, showing how the semi automatic transmission can be versatile and effective. In addition, in a semi automatic transmission there is a computer that is in control of changing and controlling actions in the car, including the torque, the car’s speed and acceleration, the accelerator pedal position, and other important components that dictate the safety and performance of the vehicle. The main function is to work to determine the timing and the direction of the gear shifting. 

When the entire control unit, or car’s computer, determines that there is a situation where the gear changing is necessary it then turns on, or engages, the clutch to disengage the semi automatic transmission from the engine’s controls. Then, at this point, the actuators will turn on the gear shifting and disengage the clutch, reconnecting the bridge between both the engine and the transmission.

The two most common semi-automatic transmissions are-

1.     Dual-clutch Transmission

2.     Sequential Transmission