The purpose of this paper is to present the origins and the
technology of the different types of AWD (All Wheel Drive) and 4WD
(Four Wheel Drive) systems currently available and the wide
potential to incorporate such technologies to the vehicles made in
Brazil. In the Brazilian market the 4WD and AWD vehicle options are
available only on expensive pickups and imported SUVs, which
include only a small part of the total market. Conversely, there
are a large number of 4WD & AWD technologies available in
developed markets that are not currently available in the South
American markets.
Most South American consumers regard vehicles with 4WD/AWD
systems as off-road vehicles to be driven in the countryside, in an
off-road environment. These markets still don`t have a clear
understanding of the differences between 4WD and AWD, and the
benefits of each.
This paper will describe the concepts, the architecture and the
operations of such systems and point out the correct application of
each ones. Some of these systems are more adequate for off-road
usages while others are more focused on safety on slippery roads.
Others are designed to enhance the driveability and vehicle
control. On the other hand there are 4WD systems that are more
efficient for commercial vehicles while others are more adequate
for city traffic passenger cars. This paper will also encompass the
main components that constitute the 4WD and AWD system and the
interface of such systems with Engine Management Strategy,
Transmission Management, ABS, Traction Control and Stability
Control in order to provide more safety, performance and low fuel
consumption. The paper will also present and explain low cost AWD
system such as the PTU (Power Transfer Unit) usually applied at
crossover vehicles and passenger cars. The cutting edge in AWD
Technology, the Torque Vectoring, will also be presented. The
message of this paper is to point out the large array of new 4WD
and AWD technologies currently available on developed markets and
the great potential we have to bring these technologies to the car
makers in Brazil for the benefit of the customer and the Brazilian
economy.