Fire-Extinguishing System, Basic Function - GF86.10-P-9900A
Model all (CAR)
with code Z21 (Fire extinguishing system
Overview
This document contains information on: :
- General
- Function requirements
- Function
- Selftest
- Monitoring
- Pressure monitoring
- Output of fault messages
- Activate fire-extinguishing system
- Automatic activation
- Manual activation
General
The fire-extinguishing system can fight fires under the vehicle and in the engine compartment. The fire extinguishing system can be actuated manually or automatically. Extinguishing powder is used to fire fighting.
The nozzles on the fire extinguishing system are distributed on the vehicle floor and the engine compartment as follows:
- 2 nozzles in area of rear bumper
- 3 nozzles on left passenger compartment armor plate
- 3 nozzles on right passenger compartment armor plate
- 2 nozzles in left and right front upper engine compartment
- 2 nozzles in area of front bumper
Function requirements
- Vehicle speed v < 10 km/h
Function
Selftest
When circuit 15 is switched on, the LED in the fire-extinguishing system button and the LED in the emergency fresh-air system/fire extinguishing system activation button in the Guard operating unit light up for approx. t = 1 s. If the LED's still illuminate after expiration of this time, the fire extinguishing system and emergency fresh air system control unit recognizes a fault and the function of the fire extinguishing system is limited. The warning buzzer is actuated and the "a" message is indicated in the instrument cluster.
Monitoring
The fire extinguishing system and emergency fresh air system control unit monitors the following component parts for signal failure plausibility:
- Emergency fresh air system/fire extinguishing system activation button
- Fire extinguishing system button
- Fire extinguishing system temperature sensor
- Extinguishing agent tank squib
Pressure monitoring
The pressure in the extinguishing agent tank is detected by the extinguishing agent tank pressure sensor. The fire extinguishing system and emergency fresh air system control unit directly reads in the signals from the fire extinguishing agent tank pressure sensor. At a pressure of approx. p < 40 bar or in the case of a detected fault in the fire-extinguishing system, the fire extinguishing system and emergency fresh-air system control unit outputs a warning message via the warning buzzer, the LED in the fire-extinguishing system button and the instrument cluster.
Output of fault messages
A message is output by the instrument cluster in the event of a malfunction to indicate errors to the driver.
Activate fire-extinguishing system
The fire extinguishing system can be actuated manually or automatically.
Automatic actuation:
The temperature is monitored by two temperature sensor circuits.
The temperature sensor circuit 1 includes the following temperature sensors:
- Left upper engine compartment fire-extinguishing system temperature sensor
- Left lower engine compartment fire-extinguishing system temperature sensor 1
- Left rear axle fire extinguishing system temperature sensor 1
The temperature sensor circuit 2 consists of the following temperature sensors:
- Right upper engine compartment fire-extinguishing system temperature sensor
- Left lower engine compartment fire-extinguishing system temperature sensor 2
- Left rear axle fire extinguishing system temperature sensor 2
The fire extinguishing system temperature sensors permanently sense the ambient temperature. The fire extinguishing system and emergency fresh air system control unit directly reads in the signals from the fire extinguishing system temperature sensors.
If the temperature threshold of approx. T = 160 °C is exceeded at just one of the two temperature sensor circuits, the fire extinguishing and emergency fresh-air system control unit activates the fire extinguishing system. The extinguishing agent tank opening mechanism is not actuated. A manual activation via the fire-extinguishing system button is possible.
If the temperature threshold of approx. T = 160 °C is exceeded at both sensors circuits within t = 90 s, the fire extinguishing and emergency fresh-air system control unit activates the fire- temperature sensor extinguishing process by actuating the extinguishing agent tank opening mechanism.
Manual activation:
To actuate the fire extinguishing system manually, the emergency fresh air system/fire extinguishing system activation button in the Guard operating unit must be actuated first. The LED in the fireextinguishing system button starts to flash for approx. t = 6 s. The warning buzzer additionally issues a warning tone in the Guard operating unit. During this time, the fire extinguishing system can be activated by actuating the fire-extinguishing system button (at least t = 1.5 s). The fire extinguishing system and emergency fresh-air system control unit directly reads in the status of the emergency freshair system/fire extinguishing system activation button and the fire extinguishing system button, actuates the LED in the fire extinguishing system button and the warning buzzer, and starts to extinguish by actuating the opening mechanism of the extinguishing agent tank.
If actuated automatically or by actuating the emergency fresh air system/fire extinguishing system activation button, the "Air recirculation" function is activated and the ventilation deactivated momentarily to prevent penetration of smoke or extinguishing powder into the passenger compartment. The fire extinguishing system and emergency fresh-air system control unit transmits the associated request directly to the special vehicle multifunction control unit (MPM). The special vehicle multifunction control unit (MPM) passes on the request to the climate control unit via the CAN for the vehicle interior.
The air recirculation function can be stopped at any time by actuating the air-recirculation mode button at the air conditioning control panel.
| Function schematics | |||
| Function schematic for fire-extinguishing system | Model 223 with code Z21 (Fire extinguishing system) | PE86.10-P-2500-97A | |
| Additional basic functions | |||
| Air-recirculation mode, basic function | GF83.40-P-1002A | ||
| Component descriptions | |||
| Fire extinguishing system and emergency fresh-air system control unit, component description | Model 223 with code Z21 (Fire extinguishing system) | GF86.10-P-2119A | |
| Fire extinguishing system temperature sensor component description | Model 223 with code Z21 (Fire extinguishing system) | GF86.10-P-2126A |