| If you're wondering what all wheel drive cars are, | | | | Unfortunately for these early innovators, the 4w |
| the simple way to understand the concept is to | | | | drive vehicle would not find its niche in the |
| think of it as a four-wheel drive vehicle that is | | | | automotive world until World War II. |
| always in four-wheel drive mode. This means that | | | | When the US military needed vehicles that were |
| the system usually has a centered drive train | | | | able to reliably travel anywhere, including over |
| differential that allows all four wheels to | | | | poor terrain, the Jeep quickly became the world's |
| simultaneously use torque generated by the | | | | best known fwd vehicle. This ubiquitous symbol of |
| engine. | | | | American troop transportation was a staple in |
| A differential is a device that allows two output | | | | both the European and Pacific theaters of war. |
| shafts to be driven at different speeds by a | | | | While most AWD vehicles use the |
| single input shaft, evening the torque evenly and | | | | aforementioned system of multiple differentials or |
| dividing the turning speed. The first four wheel | | | | another similar setup, there have been a few that |
| steering, multiple differential system was patented | | | | are notable for their use of multiple engines driving |
| in 1893 by English engineer Bramah Joseph Diplock. | | | | separate axles, as in the case of Citroen's 2CV |
| The first car to utilize the four-wheel driven | | | | Sahara. Some of these hybrid vehicles also power |
| design was an electric vehicle developed in 1899 | | | | their AWD systems through paired electric |
| by none other than Ferdinand Porsche. | | | | motors. |