The fully electric steering column adjustment enables the driver to set the steering wheel to a convenient position. Here, the steering column can be moved by electric motors in two levels. The driver can use the steering-column adjustment switch to set length and tilt of the steering column manually. In the length and in the tilt. Various positions of the steering column can be stored in the seat memory and called up; the steering column then sets itself to the specified position. In the case of automatic convenience entry (entry and exit), the steering column moves to the most forward and highest position. After deactivation of automatic convenience entry, the steering column returns to the original position.
Control modules
The fully electric steering column adjustment function is integrated in the center console switching center (SZM). The SZM control module controls the motor gearing units for the longitudinal and tilt adjustment of the steering column. The SZM control module also stores and manages the memory positions of the steering column. With a memory interrogation, the stored coordinates for each steering column position are converted into control movements for the steering column.
Electric motor for longitudinal and tilt adjustment of the steering column
The electric motor for longitudinal and tilt adjustment of the steering column adjusts the inclination of the steering column by means of a gearing unit.
Electric motor, change over of axis of movement, steering column
The electric motor, change over, axis of movement, steering column, is used to select height or longitudinal adjustment. The motor switches via a change gear to the required adjustment level.
Steering-column adjustment switch
The steering-column switch is used to set the steering column manually. The steering-column adjustment switch transmits the information for the longitudinal and tilt adjustment of the steering column via the steering column switch cluster (SZL), the byteflight, the Safety and Gateway Module (SGM) and the K-CAN to the SZM control module.
Driver's door contact
The driver's door contact sends its signal across the driver's door module (TMFA), the byteflight, the Safety and Gateway Module (SGM) and the K-CAN to the SZM control module. The signal is required for the automatic convenience entry.
Manual steering column adjustment
Manual adjustment is performed by the driver by operating the steering-column adjustment switch. The SZM control module receives the signal across the K-CAN. The signal ”operation steering column adjustment” is transmitted in cycles when the adjusting switch is operated. When the switch is no longer being operated, the signal ”not operated” comes once. First of all, the SZM control module activates the electric motor for changing over the direction of movement. The selected adjustment level is set via the change gear. The adjustment motor is activated for as long as the signal is received and stops at the signal ”not operated”. If the cyclical adjustment signal fails to arrive twice, the steering column adjustment is also stopped.
Automatic steering column adjustment as memory call-up
The location of the steering column is picked up a Hall sensor for each adjustment direction at the gearing outputs of the steering column adjustment. Starting from each initial position, the relative adjusting path is measured and stored. These coordinates can be stored in the SZM control module. In the case of a memory call-up via the bus, the coordinates stored in the SZM control module are called up. The SZM control module activates the changeover motor until the specified position of the steering column is reached.
Automatic steering column adjustment as automatic convenience entry
When the automatic convenience entry is activated, the following sequence is started:
1. The tilt adjustment moves to the top position. 2. The longitudinal adjustment moves the most forward position (direction of travel).
The control of the automatic convenience entry is dependent on the following signals:
- Terminal_R, comes from the Car Access System (CAS) - Terminal_15, comes from the Car Access System (CAS) - signal driver's door contact
These signals are received by the SZM control module via the K-CAN. The automatic convenience entry is activated when:
Terminal_15 and Terminal_R are switched off Terminal_15 is switched off with the driver's door open, the driver's door is opened after Terminal_15 is switched off (but Terminal_R = on).
The automatic convenience entry is deactivated when Terminal_15 is activated. The steering column moves to its normal position.