Torque Control: The Benefits of Intelligent All Wheel Drive


Most people are familiar with four-wheel drive. When it was first conceived in 1893, no one really knew just how important it would become, except perhaps its inventor, Bramah Joseph Diplock. But, today, there’s a new kid on the block that promises to de-throne the king of traction control.

How All-Wheel Drive Works

All-wheel-drive systems (AWD) are a type of differential configuration where all wheels of the vehicle receive power from the engine. Usually, this power is electronically regulated. But, in early models, a mechanical differential did all of the work.

In slippery conditions, the center differential can be locked, manually or automatically, depending on the specific vehicle. When a manual center differential is engaged, the front and rear driveshafts rotate at the same speed. In other words, the front and rear wheels are “locked” together, and they receive power, allowing the vehicle to move through areas where one or two of the tires might lose traction.

Up to three wheels can lose traction in these systems and the vehicle will still have power to drive through the terrain.

In automatically locking AWD, a Torsen differential system, viscous coupling, and multiplate hydraulic clutch, or a similar traction device is used with the center differential to help lock the drives together.

Torque is transferred from the axle that slips to another axle that still has traction. As soon as the wheel slip is eliminated, the device unlocks, allowing normal driving with two primary drive wheels.

Some automatic systems employ an “on demand” system where, under normal driving conditions, only one axle is powered. When wheel slippage is sensed (usually through anti-lock braking systems), a multiplate hydraulic clutch, viscous coupling, or something similar locks and engages another axle.

Torque is transferred away from the slipping wheels to wheels that grip.

The main difference in these systems is that the device used in automatic systems replaces the center differential. These systems can also accommodate predictive or “real-time” anti-slip AWD by proactively locking the traction control device before wheels start to slip.

Why The New Intelligent AWD Is Better

Traction control systems are now commonplace, even in mid-priced and lower-end vehicles. But, new intelligent AWD systems are starting to crop up.

If you’re in the market for a new vehicle, you’re probably curious about some of the new offerings. In fact, many people wonder why buy an Explorer, when there are so many other options out there. And one of the most fascinating reasons is that Ford is an early adopter of these new intelligent systems.

The IAWD (Intelligent All Wheel Drive) systems being developed now automatically vary the amount of torque being applied to the wheels at any given time.

The first type of IAWD being used now is a front-wheel drive dominant system. These vehicle drive like normal FWD cars, and engage IAWD only when traction is lost at the main drive wheels.

The second type is where power is sent to all wheels by default, and more power can be allocated to any wheel on-demand.

The third type is where only the rear wheels receive power under normal circumstances, with the option of FWD traction when needed.

Ask your car dealer about the options currently available, and test drive a vehicle with these new advanced systems. They drive somewhat differently from what you’re used to. And, it could just be the best thing that’s ever happened to the automotive industry since the original 4-wheel drive concept.

Kyle Marshall works in the auto industry. He also has a real passion for cars and shares his knowledge of features and issues with an online audience. He regularly writes for a variety of consumer and automotive websites.

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