GF91.25-P-5202LEA Dynamic Seat Control Unit, Component Description

GF91.25-P-5202LEA Dynamic Seat Control Unit, Component Description
- with CODE (432) Left and right dynamic multicontour seat as of Model Year 2010 /YoM 09 model refinement package

Component Identification:

Location
The left and right front dynamic seat control unit is located in the center of the driver seat or front passenger seat backrest frame.

Tasks
- Inflation and deflation of the multicontour backrest in accordance with the requests issued by the driver or front passenger
- Control of massage function via left front seat massage function actuator motor (M94) or right front seat massage function actuator motor (M95) actuated by activation by the driver or passenger via the COMAND control unit (A40/3)
- Actuation of the dynamic lateral support
- Communication via the interior CAN (CAN B) with the left front seat control unit (N32/1) or right front seat control unit (N32/2)
- Adjustment of seat hardness and seat contour
- Actuation of internal pressure valves for seat backrest and seat cushion as well as shoulder, lateral support for seat cushion and seat backrest.
- Actuation of the driver dynamic system main valve (Y24/20) or passenger dynamic seat main valve (Y24/21)
- Adjustment of stored pressure values when calling memory function and storing actual contours (with code (275) Memory package for electrically adjustable front seats)
- Actuation of the pneumatic pump for dynamic seat control (M40/1)

These are grouped as follows:
^ Reading in of sensors and signals
^ Evaluation of input factors
^ Actuation of components

Reading in of sensors and signals
These input factors are read in via the following connections:
^ Direct line
^ Interior CAN

Direct line
- Circuit 30g
- Tml. 31
- One limit switch in left front seat massage function actuator motor or right front seat massage function actuator motor
- Piezo sensor in driver dynamic seat main valve or passenger dynamic seat main valve (pressure sensor valve) for measurement of air pressure in seat cushion of massage insert in seat backrest
- Piezo sensors read in by internal direct line, in front dynamic seat control unit for measuring air pressure of contour insert in seat cushion and seat backrest.

Interior CAN
The front dynamic seat control unit communicates via the interior CAN with the:
- Left front seat control unit; adjustment and storage (with code (275) Memory package for electrically adjustable front seats) of seat contours
- Right front seat control unit; adjustment and storage (with code (275) Memory package for electrically adjustable front seats) of seat contours
- the pneumatic pump for dynamic seat control; actuation of the compressed air supply
- the central gateway control unit (N93) as router for signals from:
- the ESP control unit (N47-5); for the dynamic and PRE-SAFE function
- the COMAND control unit for adjustment functions

The signals are read in/transmitted by the front dynamic seat control unit. The functions resulting therefrom are described in the corresponding function descriptions (see block diagram or function schematic).

Evaluation of input factors
The input factors read in are evaluated by the dynamic seat control unit. The air cushions of the contour seat in the seat are actuated by the piezo valves integrated into the dynamic seat control unit. The air cushions in the massage insert are actuated by the corresponding dynamic seat main valve and the front seat massage function actuator motor,.

Actuation of components
The actuation of the components takes place via the following connections:
^ Direct line
^ Interior CAN

Direct line
- Windings in the left front seat massage function actuator motor or right front seat massage function actuator motor
- Driver dynamic seat main valve or passenger dynamic seat main valve

Interior CAN
The dynamic seat control unit communicates via the interior CAN with the:
- the pneumatic pump for dynamic seat control; for actuation of the compressed air supply
- the central gateway control unit as router for signals for the COMAND control unit for display functions and feedback signals

Design
Piezo sensors are installed in the left and right front dynamic seat control unit next to the intelligent circuit. These sensors are used to measure and monitor the pressure. The air pressures in the cushions of the contour insert are adjusted by the piezo valves integrated into the dynamic seat control unit.

The dynamic seat control unit is connected to the driver dynamic seat massage function main valve or passenger dynamic seat massage function main and the pressure sensor via the 14-pin connector.

It is also connected to the winding in the seat massage function actuator motor by this connector.

The 7-pin plug connects the dynamic seat control unit via the left front seat control unit or right front seat control unit with the interior CAN and the power supply.

Function

Short-term control
The short-term control is actuated following each adjustment process (manual adjustment, memory request, initialization) for a certain period of time. It compensates for excess pressure deviations from the specified pressure of each air cushion (cushion areas, connected to a pressure sensor, are jointly in the temporary control phase) within a parameterized time period. Vacuum deviations during this phase are not compensated for. This phase is used to immediately compensate for large pressure jumps when sitting down and leaning back in a comfort-oriented fashion.

Long-term control
After the short-term control, the long-term control becomes active for the active cushions, until it is reset by events with a higher priority. Almost without the customer noticing, the lumbar support is regulated in the specified time frame such that the mean value of the actual pressure adjusts to the specified pressure within the repeatability over a certain period of time.

If an adjustment to the specified pressure cannot be achieved in several consecutive steps, a "gross leak" is detected. The affected cushion area is deactivated completely until the malfunction is no longer present.

Non-active air cushions are deflated in increments to a pressure less than the minimum pressure.

Variants
There are no variants for the hardware for the dynamic seat control unit.

The assignment for driver or front passenger seat and the country or left-hand/right-hand drive vehicle assignment is also coded by the software.