Passive Safety Systems - Overvew: Overview BMW Z3 E36 рестайлинг

MRS III Principle of Operation

As with previous MRS systems, the triggering thresholds are programmed in the MRS III control module. These thresholds are determined by BMW through crash and vehicle testing during the design and development of the vehicle. These thresholds will vary depending on the vehicle type.

There are several different thresholds for airbag and safety restraint deployment

1. Belt pre-tensioner threshold for activation of the seat belt tensioners.
2. Airbag threshold #1 - the first level of activation for the two stage front airbags, always deployed first when the front triggering threshold is reached.
3. Airbag threshold #2 - the second level of the two stage front airbags, can be deployed simultaneously or after a time delay, depending on the severity of the impact.
4. Rear crash threshold - for activation of the seatbelt tensioners with a rear impact.
5. Battery safety terminal threshold - for activation of the BST with airbag deployment.
6. Side airbag/ITS threshold - for deployment of the side and thorax airbags.

Overview

The MRS was introduced for the 1996 - E38 and 1997 model year E39. The MRS II was introduced on E38s (5/97 production) and the E39 from start of production (9/97). The MRS and MRS II include the following restraint/safety components

Scheme 7

1. Driver and passenger front airbags (MRS/MRS II).
2. Side impact (Thorax) airbags for the driver and front passenger (MRS/MRS II).
3. Side impact crash sensors left/right (MRS/MRS II).
4. Side impact (Thorax) airbags for the rear passengers (MRS II).
5. Head Protection System (HPS) for the driver and front passenger (MRS II).
6. Battery Safety Terminal - BST (MRS II).
7. Hall Sensor seat belt switches (MRS II).

SYSTEM OVERVIEW

The ZAE control system is similar to the MRS system in that impact detection and airbag triggering are combined functions integrated into the ZAE control module.

Scheme 8

The early SRS consists of the following components

Scheme 9

1. Driver's air bag unit with gas generator - mounted in the center of the steering wheel.
2. Passenger's front air bag was added beginning with 1993 model year E32/E31.
3. Contact ring - under the steering wheel
4. Front Impact Sensors - mounted on the left and right wheel housings.
5. Control module.
6. SRS warning lamp.

SIEMENS OPERATION

The SRS control module and SRS warning lamp receive power when the ignition is switched on (KL R). The control module performs a self check and charges the internal capacitor to approximately 35 volts. The capacitor ensures that enough power will be available for airbag activation. If the self check is "OK", the warning lamp goes out and the system is ready for activation should the need arise.

During the instant of activation the capacitor voltage is used to energize the ignition pill of each airbag gas generator. The airbag fills rapidly with a nitrogen gas (N2) supplying the needed margin of safety.

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RPS COMPONENTS - OPERATION

The main components of the RPS includes the following