Allwheeldrive

Allwheeldrive, commonly referred to as all-wheel drive or AWD, describes a drivetrain arrangement capable of sending torque to all four wheels, either permanently or on demand. Its purpose is to improve traction and stability on varying surfaces, such as wet, snowy, or uneven pavement, compared with two-wheel-drive layouts. AWD is widely used in passenger cars and crossovers, and it is distinct from dedicated off-road four-wheel-drive systems.

AWD systems generally fall into two categories: permanent and on-demand. Permanent AWD uses a center differential or a continuously engaged coupling to deliver power to both axles at all times. On-demand AWD relies on an electronically controlled clutch or a transfer mechanism to engage the rear axle when wheel slip is detected or extra traction is needed. Some configurations also incorporate torque-vectoring features to adjust distribution between wheels for improved handling.

How AWD operates varies with design, but most systems monitor wheel speed, throttle input, steering, and yaw. The control unit then redistributes torque to reduce slip and maintain stability. In many vehicles, AWD works together with electronic stability control, traction control, and braking systems to enhance overall safety and performance.

Benefits of allwheeldrive include better acceleration and grip in slippery conditions and improved cornering stability. Limitations include added weight, higher cost, and potentially reduced fuel economy. Tire choice and condition remain crucial, as AWD does not compensate for worn or inappropriate tires. The term allwheeldrive is often used interchangeably with AWD, though branding and marketing vary by manufacturer.