Three new technologies from Delphi Corp. are helping the new Range Rover Sport achieve levels of dynamic performance and comfort that are widely regarded as setting new standards for a high-performance SUV.
The combination of advanced air suspension and a new compact version of Delphi’s Active Stabilizer Bar System (ASBS) has been credited with helping to provide exceptional handling combined with best-in-class ride.
The new vehicle is also available with a new generation of Delphi’s Forewarn Smart Cruise Control that will help the driver maintain a driver-selected time gap behind the vehicle ahead at highway speeds.
DYNAMIC RESPONSE SYSTEM WITH DELPHI’S NEW ROTARY ACTUATORS
Delphi’s new rotary actuators replace conventional stabilizer bars to provide an exceptionally compact roll control system. Delphi worked closely with Land Rover’s chassis team, who integrated Delphi ASBS actuators and valve blocks at both the front and rear, making Range Rover Sport the first vehicle to be fitted with this new technology.
A traditional stabilizer bar improves vehicle stability through corners by reducing roll angle and managing the tire-to-road interface. Heavy vehicles with a high center of gravity typically require stiff, large diameter stabilizer bars but these will substantially reduce ride comfort and refinement and can also reduce traction in some conditions. Traditional stabilizer bars also restrict wheel travel, potentially compromising off-road behavior, and can create an effect known as "head toss" that can be particularly uncomfortable in vehicles where the occupants are seated high. Land Rover’s Dynamic Response system, incorporating Delphi’s ASBS technology, helps minimize all of these issues.
ASBS technology splits the conventional stabilizer bar in the middle. At the intersection of the two roll-bar sections, a computer-controlled actuator applies a variable level of torque. When the vehicle is traveling in a straight line, the system effectively decouples the stabilizer bars from the vehicle, improving ride comfort and allowing large wheel articulation to increase off-road ability. In a corner, roll-stiffness is instantly increased by applying torque to each end of the bar.
Delphi’s triangulated link ASBS actuators have been available on the Land Rover Discovery from the 1999-model year, giving the vehicle manufacturer considerable confidence in the technology. With the independent suspension configuration required for exceptional on-road performance, however, the Range Rover Sport could not accommodate this system. Being faster and heavier, the new vehicle also required more control torque than the previous generation system could provide. It was therefore decided to take a clean sheet of paper and develop an all-new actuator technology.
ADVANCED AIR SUSPENSION
The blend of talents required by the suspension of a Range Rover Sport is considerable. As well as safely managing the 385 bhp and 550 Nm of the supercharged engine option, it must provide the 2,572 kg vehicle with sportscar handling, limousine ride quality and world-class off-road ability.
Land Rover chose air suspension because it allows low spring rates (providing good ride quality) without compromising the ability to maintain ride height when loaded or trailering. Air suspension also allows the ride height to be increased when traveling over difficult terrain. Delphi already supplies compact air suspension modules for the new Discovery (called LR3 in the U.S.) and the current Range Rover, so was a logical choice as a key suspension supplier for the new Range Rover Sport.
When designing its air spring technology, Delphi chose a modular approach to allow fast adaptation to new applications. For the Range Rover Sport, the system uses high-pressure monotube gas shock absorbers to provide high damping forces and excellent high frequency control. The air springs are stiffened and a new type of single point top mounting has been developed to reduce the transmission of road noise into the vehicle body. The new gas shock absorbers have an 18 mm shaft diameter, thought to be the largest in production for a passenger vehicle, and fit into the existing air sleeve without any modification.
FOURTH GENERATION ADAPTIVE CRUISE CONTROL
The Range Rover Sport is also one of the first vehicles to be fitted with Delphi’s fourth-generation adaptive cruise control (ACC), which helps the driver maintain a selected time gap behind the vehicle ahead. At highway speeds, if the lane ahead is clear, the system will maintain the cruising speed set by the driver. When slower traffic is detected in front of the vehicle, the system will automatically maintain a driver-selected headway (the time gap between the vehicles, adjustable between 1.0 and 2.2 seconds) using throttle control and limited braking. If the closing speed is sufficient to require manual intervention, audible and visual warnings are given.
At the heart of Delphi’s ACC is a mechanically scanning 76 GHz microwave radar sensor, integrated with a yaw sensor in an easily packaged housing that in the Range Rover application is mounted behind a polymer body panel in the nose of the vehicle. A separate Electronic Control Unit processes the radar data to calculate the range (distance), rate (closing speed) and azimuth (lateral deviation) of targets up to 150 m ahead and delivers appropriate control signals to the engine and brake control systems via the vehicle’s CAN bus.
Delphi’s narrow-beam radar system provides greatly improved angular accuracy and target discrimination compared with rival multi-beam fixed sensor systems. The wide-angle view (up to 15 degrees) provides early warning of vehicles entering the lane ahead and superior tracking in tight curves. It also allows an automatic alignment feature to compensate for installation tolerances and for changes in sensor alignment during the vehicle’s life, reducing fitting costs for the vehicle manufacturer and increasing system reliability.
The Delphi Forewarn system also includes a Forward Alert feature that the driver can set to provide audible and visual alerts if braking is required due to slower-moving vehicles ahead. Drivers can adjust system sensitivity to adapt alert levels to their preferred driving style. The system will also warn the driver if mud, snow or other material is blocking the sensor.