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

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MODEL 212.095/098/298

High-voltage pyrofuse

Function requirements, general

Circuit 15R ON

The status of circuit 15R is sent by the electronic ignition lock control unit (N73) via chassis CAN (CAN E) (up to 28.2.13) or via chassis CAN 1 (CAN E1) (as of 1.3.13) to the supplemental restraint system control unit (N2/10).

Deploying a pyrofuse (F63), general information

To avoid any possible fire hazard following a crash event, it is necessary to remove the voltage of the high-voltage components.

Function sequence for triggering the pyrofuse

Inside the pyrofuse housing the power supply for the interlock circuit is designed as a busbar with predetermined fracture point (3). After a crash event has occurred, the pyrofuse is directly actuated 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 predetermined fracture point and disconnects the busbar. The interruption of the interlock circuit triggers the shutdown of the high-voltage components. After the shutdown the high-voltage components are de-energized.

Time sequence:

Piston movement starts after t = 300 μs.

Line rail disconnection is finished after t = 450 μs.

Fig 1: Pyrofuse Deploying (F63) Function Diagram

Courtesy of MERCEDES-BENZ USA

Overview of system components for supplemental restraint system

GF91.60-P-9996FL