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Restraints Deploy Strategy for ECE21-Annex8 Requirements Disclosure Number: IPCOM000249241D
Publication Date: 2017-Feb-13
Document File: 2 page(s) / 636K

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Restraints Deploy Strategy for ECE21-Annex8 Requirements

1. Introduction

As part of ECE21 regulation, Annex8 is a dynamic compliance method using Vehicle Impact Tests, Sled Level

testing and CAE to demonstrate no contact between Occupant’s Head and Vehicle’s Instrument Panel with

three occupant sizes (95th, 50th & 5th) and three orientation angles (-18 deg, 0 deg & +18deg).

The main challenges are:

1. Balance Performance between regulations (ECE21 & Euro NCAP) and Occupants (95th, 50th & 5th).

2. Dynamic Test conditions for Annex8 are generic and aggressive compared to Euro NCAP Modes.

A New Restraints Deploy Strategy for ECE21-Annex8 is developed: The proposed deploy strategy enables to

meet Annex8 and Euro NCAP Occupant performance targets with minor tuning of Restraint Systems.

2. Method

Typical Restraint Deploy Strategies with pulse as defined by ECE21 / GB11552 results in an early deployment

time accordingly to “5 inch /30 ms rule”. A New Deploy Strategy was developed based on extrapolation of

vehicle crash sensor calibration data.

In a typical sensing strategy, two separate paths are utilised for pre-tensioners and frontal airbags:

 Pre-tensioners primarily rely on the Front Crash Sensor (FCS) signal supported by the Tunnel Crash

Sensor (TCS) confirmation which allows an early signal prior to structure deformation.

 Frontal airbags primarily rely on the TCS signal supplemented by the FCS.

This strategy results in almost identical deployment times

for the airbag and pre-tensioners for full frontal crash tests

(100% overlap) because FCS and TCS are in line with the

crash primary direction of force (Fig 1).

In crash modes where the loading is offset (e.g. 40% offset)

or angled (e.g. 30 degree angular), the difference in the two

deployment times is clearly visible. This is due to the FCS

being in the crush area and will measure significant

deceleration whereas the TCS will delay the deploym...