Triggering Strategy

Triggering Strategy

A completely new safety system, the ISIS,has been developed for the E65/E66. With its decentralized satellites fitted at strategic points in the vehicle, it is possible for the first time to implement 100%, all-round detection on the vehicle.

Triggering Thresholds

Numerous crash and road tests under extreme conditions have been used to set the BMW triggering thresholds for all possible types of accidents.

The triggering thresholds are divided according to crash severity (CS). There are four types of crash severity:

1. CS 0 Light collision No airbag activation

2. CS 1 Medium collision Possible airbag triggering, stage 1

3. CS 2 Severe collision Airbag triggering, stage 1

4. CS 3 Very severe collision Airbag triggering, stage 1 + 2

The triggering thresholds are set depending on the crash severity as well as various other factors, (e.g. 0°, 30°, or offset crash).

Other important information is also included, such as whether the occupant is wearing a seatbelt or not.

This results in the trigger thresholds for the activation of the various restraint systems.

Depending on the type of accident, different crash severities have been specified:

- Frontal crash CS 0, CS 1, CS 2,CS 3

- Side-impact crash CS 0, CS 1, CS 2

- Rear crash CS 0, CS 1, CS 2







If a fault is detected in the seat occupancy detection system, it is assumed that the seat is occupied and the restraint systems are activated.

If a fault is detected in the seatbelt buckle detection system, it is assumed that the seatbelt is not fastened and the restraint systems are activated with CS1.

In spite of this an attempt is made to activate the seatbelt lock tensioner.

Frontal Collision CS1

The table below shows the activated actuators with crash severity 1.







Frontal Collision CS2/CS3

The activation of the airbag stages and the belt tension limiter takes place via differentiation of the crash severity with various decelerations on activation.







Side Collision, Left CS1







Side Collision, Left CS2







Side Collision, Right CS1







Side Collision, Right CS2







Rear Collision CS1







Rear Collision CS2