Realizing a more comfortable ride
When driving, a vehicle will encounter large and small bumps on the road. As the vehicle passes over certain bumps, passengers may feel a fore-aft pitching motion. The Active Ride Control moderates this by controlling the engine and brakes, delivering a smoother driving experience.
When the driver depresses the accelerator pedal and engine torque is increased, the front half of the vehicle rises up slightly. Conversely, when the foot is taken off the accelerator pedal and engine torque is reduced, the front of the vehicle lowers back down. The raising and lowering of the front of the vehicle results in the vehicle exhibiting pitch behavior.
Active Ride Control takes advantage of this phenomenon to counteract the pitching caused by bumps. The engine torque is varied slightly according to the bumps in the road surface, which decreases the pitching motion of the vehicle and allows the vehicle’s occupants to have a more enjoyable driving or riding experience.
In addition, the vehicle suspension is fitted with shock absorbers which dampen the vertical and pitch motions of the vehicle. When dampening is strong, the motion caused by bumps on the road surface is quickly reduced. Conversely, with weak dampening, the motions caused by bumps can continue for a long time.
Nissan discovered that when the brake is applied, it has the effect of strengthening the dampening of body motion. Active Ride Control includes technology developed to reduce vehicle pitching when passing over a bump by automatically applying a very small amount of braking. The amount of braking is not enough to slow the vehicle down appreciably, but still results in faster dampening of the pitch motion than the vehicle using shock absorbers alone. With Active Ride Control, the pitching that follows when a vehicle passes over a bump is decreased in amount and duration, and the driving experience becomes more comfortable.
When a vehicle passes over a bump, the wheels speed fluctuates slightly when compared to the same vehicle driving on a flat surface. Using sensors to detect the change in the speed of the wheels, the system determines when the vehicle is moving up and down.
When the pitching is minor, ride quality can be improved by increasing or decreasing the engine torque. When the pitching is greater, the system applies the brakes and this helps minimize the body motion of the vehicle. The engine torque variations and the brake applications are small and smooth. They calm the vehicle body motion but do not result in appreciable increases or decreases in vehicle speed. This allows drivers and passengers to simply enjoy a more comfortable driving and riding experience.