All-Wheel Drive
The desire for optimum traction creates the need for AWD, particularly in vehicles which are driven off-road. Shiftable AWD has been used in the commercial vehicle sector and in off-road vehicles for a long time. Success in sport led to an increased involvement on the part of many automobile manufacturers in AWDs in the early 80s resulting in the appearance of a number of concepts.
AWD is used in combination with all engine layouts. In commercial vehicles, both the front as well as rear axles can be designed in the form of driven tandem axles.
The figure shows the possible engine layouts in AWD for different vehicles.