GKN has developed the world’s first Disconnect All-Wheel Drive System for the A, B and C segment vehicle platform, which improves fuel economy during steady-state cruising by up to 4%. The innovative Disconnect function enables vehicles to combine enhanced traction dynamics and stability of the all-wheel drive with improved on-highway fuel efficiency.
Senior Programme Director Hannes Prenn said, “As global demand for smaller, more efficient SUVs continues to grow, GKN’s Disconnect All-Wheel Drive System will help open new markets. This compact new system enables manufacturers to offer customers more capable and dynamic vehicles with improved fuel efficiency and CO2 emissions.”
The system responds to driver inputs and road conditions, connecting and disengaging the drive to the rear axle on demand. By eliminating rotating losses from the driveline, during steady-state cruising, fuel efficiency can be improved by up to 4% compared to permanent all-wheel drive systems.
The result is a tightly packaged all-wheel drive system, which replaces features such as the standard power transfer unit (PTU) with a monoblock housing that fully integrates the propeller shaft’s constant velocity joint. The arrangement also yields superior NVH characteristics, benefiting overall refinement of the vehicle. The clutch system at the heart of the Disconnect is a development of the arrangement in the Range Rover Evoque.
Senior Vice President of Engineering, Rob Rickell, said, “With all production, engineering and software development inhouse, GKN Driveline is the only supplier able to develop and supply such a tightly integrated all-wheel drive system. The result is the lightest, most compact and capable disconnect all-wheel drive system available in the market. The same hardware can support models built on a common platform but with different performance requirements. GKN’s software engineers fine-tune the electronic control to deliver specific brand characteristics.”
GKN Driveline’s Disconnect All-Wheel Drive System includes a power transfer unit (PTU), linked to the transmission’s final drive differential. The PTU contains a fast-disconnect device and brake that can bring the all-wheel drive system to rest upstream of the PTU’s hypoid gears. An electro-mechanically actuated clutch located in the rear axle both biases the drive torque and disengages the all-wheel drive system, downstream of the hypoid gears, to save fuel.
A dedicated driveline control unit continuously monitors vehicle dynamics and environmental conditions, disconnecting the AWD system during steady-state driving speeds when the AWD function is not needed. If the driver or conditions require more traction, the AWD reconnects within 300 milliseconds.
An active torque biasing function provides precise control of the distribution of torque between the front and rear wheels, optimising traction, stability and performance. Torque vectoring between the individual rear wheels is also possible with the system and has already been introduced on the Range Rover Evoque.
GKN Land Systems is a leading supplier of engineered power management products, systems and services. It designs, manufactures and supplies products and services for the agricultural, construction, mining and utility vehicle markets and key industrial segments, offering integrated powertrain solutions.
GKN operates four divisions: GKN Aerospace, GKN Driveline, GKN Powder Metallurgy and GKN Land Systems. Around 49,700 people work in GKN companies and joint ventures in more than 30 countries worldwide. ACI
Compiled by Krishna Kumar
