The BMW concern is the developer of the XDRive constant all -wheel drive system. Under all kinds of circumstances of the movement, the system provides a continuous, unavailable and variable distribution of torque between the rear and front axle. At the present time, XDRive is installed on car cars, fifth, and seventh series, and in addition to sports SUVs X1, X3, X5, X6.
The system is based on the generally accepted rear -drive transmission scheme. Thanks to the handout (gear transmission of the front axle drive), it is embodied in the action of the distribution of torque between the axes. In sports SUVs instead of gear, a chain transmission is installed.
Scheme of the XDRive system gearbox
XDRive is combined with the dynamic system for monitoring the Dynamic Stability Control (DSC) course stability system. It is also integrated with the Dynamic Traction Control (DTC), Hill Descent Control (HDC) and others.
Integrated Chassis Management (ICM) is responsible for the interaction of Dynamic Stability Control and XDRive systems, and communicates with Active Front Steering (AFS) of the steering system.
The principle of operation xDrive
Determined algorithms for the response of friction clutch during the operation of XDRive are:
movement with slippery surface;
passage of turns with an excess of cooking;
parking;
passage of turns with disruption insufficiency;
Touching from a place.
When moving along a slippery surface, using the Dynamic Stability Control system and blocking the friction coupling between the wheel lock of the system, the wheel slipping is removed.
With an excess of rotation in the turns, the friction coupling is in a closed position (the rear axle is entered to the outer region), and the front, torque is directed with greater force. Directly using Dynamic Stability Control using the wheel inhibitory, the movement of the car stabilizes.
During the parking lot, the car becomes the rear drive (the friction coupling is in the open position), which reduces the load on the steering control and transmission.
With insufficient rotation in the turns, all one hundred percent of the torque are sent to the rear axle, and the friction coupling is opened. Dynamic Stability Control is turned on only if necessary.
When touched by the friction clutch, to be in a closed position, and the maximum thrust is achieved by dispersing the torque in the ratio of 40 to 60. From the type of road conditions, the torque will be distributed between the axes.