Powertrain

Powertrain is a group of several components that generate and transmit energy to produce a work. In a car, component that produces energy is the combustion engine, then the energy transmitted to the gearbox, then the energy is transfered to the differential through the drive shaft, after which the energy used to drive the wheels.

There are many types of engines which are classified according to the fuel, combustion chamber volume, number of cylinders, cylinder arrangement, and others. The next figure shows an engine.

Transmission on the car that we often hear is divided into automatic and manual transmission. On automatic transmission we do not need a help of the clutch pedal to change the speed, instead of a manual transmission. 

Then, the energy is supplied to differential through the drive shaft. The differential functions to convey and manage energy to the right and left wheels, so that when the vehicle is turning energy supplied to the wheels are not the same between right and left, and so is the speed.

Reffs.: wikipedia.org, 2carpros.com