Deploying of pyrofuse, function - GF91.60-P-2011CE

MODEL 204.0/2 as of model year 2009/YoM 08 

MODEL 204.3 

MODEL 204.9 

Function requirements, general 

• Circuit 15R ON

The electronic ignition control unit transmits the circuit status of circuit 15 (N73) via chassis CAN (CAN E) to the supplemental restraint system control unit (N2/10).

Deploying a pyrofuse, general 

To avoid any possible fire hazard following a crash event, it is necessary to disconnect the starter (M1) and alternator (G2) quickly and reliably from the on-board electrical system.

Function sequence for triggering the pyrofuse 

The central line to the starter and to the alternator is designed as busbar with predetermined fracture point (3) inside the pyrofuse housing.

After a crash, the pyrofuse 88 (F32f88) (without code (B03) ECO start/stop function) or the pyrofuse (F63) (with code (B03) ECO start/stop function) is actuated directly by the supplemental restraint system control unit.

When the pyrofuse is actuated, pressure builds up in the chamber (1). The piston (2) then moves against the busbar with predetermined fracture point, thereby disconnecting the busbar.

The status of the pyrofuse is monitored by the supplemental restraint system control unit.

Time sequence:

After t = 300 μs, the piston movement starts.

After t = 450 μs, the separation of the line rail is complete.

	Electrical function schematic, supplemental restraint system (SRS)		PE91.60-P-2052-97FAB
	Overview of supplemental restraint system (SRS) system components		GF91.60-P-9998CE