System Overview: Notes
| Index | Explanation |
|---|---|
| 1 | Lower air cushion, left |
| 2 | Upper air cushion, left |
| 3 | Upper air cushion, right |
| 4 | Lower air cushion, right |
| 5 | Output, lumbar-support adjustment |
| 6 | Solenoid valve, changeover, active seat/lumbar-support adjustment |
| 7 | Pump for lumbar-support adjustment/active seat |
| 8 | Footwell module (FRM) |
| 9 | Active seat buttons with function indicator |
| 10 | Central gateway module (ZGM) |
| 11 | Driver's seat module (SMFA) |
| 12 | Distributor module, active seat |
| 13 | Air supply, active seat |
| K-CAN | Body CAN |
| K-CAN2 | Body CAN2 |
| LIN-Bus | Local Interconnect Network bus |
K-CAN signals at the seat module
| In/Out | Information | Source/sink | Function |
|---|---|---|---|
| In | Outside temperature | Outside temperature sensor > instrument cluster | Ambient conditions when faults are stored |
| In | Yaw rate | Yaw rate sensor > Integrated Chassis Management | Suspend active seat function |
| In | Power management | Digital engine control > Seat module | Brief suspension, in order to maintain enough power in the vehicle electrical system |
Four air cushions are integrated in the seat surface for the active seat. Two air cushions, one on top of the other, are used in both the left and right seat halves.
The air cushions are inflated with air supplied by the pump for the lumbar-support adjustment. A solenoid valve is integrated in the pump unit. The function of the solenoid valve is to change over the air supply. This ensures that only one function (lumbar support adjustment or active seat) is ever executed.
A distributor module is available for inflating the air cushions. The seat module delivers power to the distributor module as soon as the active seat is switched on.
The distributor module houses a motor, which drives an eccentric shaft. The rotation of the eccentric shaft causes the air inlets to the seat cushions to open or close.
The seat cushions are alternately inflated or deflated, depending on the position of the eccentric shaft. The air inlets are closed when the system is switched off and in the breaks between inflation or deflation.
A switch contact is integrated in the distributor module to switch on the pump for lumbar-support adjustment. The rotation of the eccentric shaft actuates the contact, which thereby signals activation to the seat module. The seat module switches on the pump for lumbar-support adjustment and changes over the solenoid valve to inflation of the seat cushions.