June 22, 2016 at 4:40 pm by Eric Tingwall | Photography by Greg Pajo, Illustration by Chris Philpot
From the July 2016 issue
Wheel articulation that improves rock-crawling traction is at odds with the flat body control that aids on-road handling. To manage the competing priorities of off-road ability and handling competence, Bentley engineers split the Bentayga’s anti-roll bars in two and fit electric motors between the halves. Using planetary gearsets to multiply torque, the Bentley Dynamic Ride system can input up to 959 pound-feet of torque to each anti-roll bar.
Given that the Bentayga’s natural habitat is paved, the system has the most effect on handling. In corners, the motors drive the anti-roll-bar ends to press down on the outside wheels and lift the inside wheels. The resulting equal and opposite forces counteract the vehicle’s body roll. The system also improves ride comfort. When the Bentayga encounters a bump while traveling straight, the motors produce an upward force that helps lift the wheels, reducing the jolt transmitted to the body. By monitoring the steering angle, the position of each wheel, and the lateral acceleration, the motors can react in as little as 0.06 second. Off-road, Dynamic Ride increases wheel articulation by decoupling the left and right wheels and using the motors to increase rather than decrease the compression or extension of the suspension.
Bentley claims it is the first automaker to use a 48-volt active anti-roll bar, but that’s not saying much. In 2005, Lexus introduced a similar system that runs on 42 volts. Bentley’s higher voltages allow capacitors to deliver the required power without the high current that a 12-volt architecture demands. Four times the voltage means just one-quarter the amperage can deliver the same power to the motors. That means the supercapacitors, which store this system’s electrical energy, deliver a peak of 30 amps per motor rather than 120 amps. Dynamic Ride adds about 35 pounds to the Bentayga’s curb weight, meaning this is a situation where engineers make a heavy vehicle handle better by making it heavier.
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