A new four-wheel-drive vehicle’s marketing materials typically don’t include much information about the kind of off-road running equipment used.
Although terminology like Intelligent AWD, 4Matic, Super Select II, and Quattro are frequently used, it might be challenging to identify the mechanical components. Confusion is also increased because manufacturers use the same brand name for various systems.
We’ve taken a close look at manufacturers’ most common four-wheel-drive systems to understand what is truly happening beneath the bodywork and identified what they can and, more importantly, cannot do.
Part-time four-wheel drive, permanent four-wheel drive (sometimes known as an all-wheel drive), and automatic four-wheel drive are the primary divisions. Each of these configurations can be approached in various ways, though.
In many four-wheel-drive hybrid models, an electric motor powers the back axle, while some completely electric vehicles use a motor on each wheel, adding another dimension to the car. But we’ll address these at a later time.
What is four-wheel drive all about
Cars need differentials on each axle that let the left and right wheels turn at various speeds to turn turns efficiently.
To account for the speed disparities between the front and rear axles, vehicles with four-wheel drive intended for high-traction surfaces (such roads) must also incorporate some middle differential.
No wheel can deliver greater torque than another when all of these differentials are open, though. As a result, when one wheel begins to spin, the other wheels experience an equal amount of torque, which is insufficient to move the car.
Various combinations of diff-locks, viscous couplings, traction control, and torque-vectoring systems are used by manufacturers to ensure that as much torque is applied to the wheels with grip without degrading the driving characteristics.
sporadic use of four wheels
Most pickup trucks still use part-time four-wheel-drive systems, which are likely the most basic technique to provide power to all four wheels.
These vehicles have a two-range transfer box installed between the transmission and axles, which serves as both a high and low-range gear changer and a two- or four-wheel drive selector.
When four-wheel drive is engaged, the transfer box transmits power to the front prop shaft through a heavy-duty chain, whereas two-wheel movement sends all power to the rear wheels. Likewise, upon returning to two-wheel drive, freewheeling hubs on the front axle are automatically engaged and disengaged.
By doing so, the driveline’s efficiency is increased, and road wear is decreased. Before the changeover to fully autonomous operation, various semi-automated variants of these hubs were introduced.
Importantly, cars with this configuration lack a center differential, which prevents the four-wheel drive from being used on public roads. There is a fixed 50/50 torque split between the front and back wheels when four-wheel drive is chosen, preventing any speed discrepancy between the front and rear wheels.