Preventive occupant protection system, basic function

GF91.40-P-9900A

Preventive occupant protection system, basic function

15.06.2020

Model	118, 177, 247
	with code 299 (PRE-SAFE)
Model	167
Model	213, 238, 257, 290
	as of model year 2021
Model	293

Overview

This document contains the following information:

 General

 Function requirement

 Function triggers

 Preventive occupant protection measures

 Reversible emergency tensioning retraction

 Seat adjustment (vehicles with seat adjustment with memory function)

 Close sliding sunroof (vehicles with sliding sunroof or panoramic sliding sunroof).

 Close side window, leaving a small gap.

 Hearing protection

General

The approach of the preventive occupant protection system is to recognize potential risks of accident at their origin. For this purpose, various sensory capabilities are used, not least through the networking with driver assistance systems. In hazard situations, different actuators are actuated according to the situation in order to deploy their protective effect before the actual impact.

If the accident fails to happen, the fully reversible systems can be restored to their default positions and are immediately ready for operation again.

Depending on the equipment installed, the preventive occupant protection system can be extended by the following functions:

 Rear collision warning system (vehicles with Driving Assistance Package)

 Preventive occupant protection system for side impacts (vehicles with PRE-SAFE® Impulse Side)

Function requirement

 Circuit 15 ON

Function triggers

The preventive occupant protection system defines the driving state based on the following parameters:

 Vehicle deceleration

 Wheel speed

 Natural dynamics of the vehicle (yaw torque, lateral acceleration)

 Steering angle

The following situations are classified as accident-critical:

 Emergency braking: Rapid brake pedal operation (startle response).

 Maximum full-stop braking: The driver's deceleration request is significantly greater than the physically possible vehicle deceleration (e.g. aquaplaning, ice or snow). Strong interventions of the anti-lock braking system (ABS).

 Severe oversteer: Swerving of rear end combined with strong ESP® stabilization interventions.

 Severe understeer: The vehicle pushes over the front wheels. Strong ESP® stabilization interventions.

 Side wind stabilization: Drifting from the lane, combined with considerable amount of ESP® stabilization intervention.

 Critical steering movements: Rapid steering at high speeds (startle response by the driver combined with excessive stress).

 Secondary accident: The occurrence of another crash after an accident.

 Vehicles with radar-assisted traffic area monitoring:

 Strong brake force boosting by BAS PLUS: Risk of collision in linear and cross traffic.

 Autonomous brake application by PRE-SAFE® Brake: Risk of collision in linear traffic.

 Autonomous course correction by the blind spot monitoring system: Course-correcting brake application when there is a risk of collision with vehicles to the side.

 Collision object detection at front/rear/side: Detection of an imminent collision.

The activation threshold for the preventive occupant protection measures is modified according to the following variables:

 ESP® mode

 Drive program (vehicles with automatic transmission)

Preventive occupant protection measures

The preventive occupant protection system activates the following measures for occupant protection in critical driving situations:

 Reversible emergency tensioning retraction

 Seat adjustment (vehicles with seat adjustment with memory function)

 Position front passenger seat.

 Adjust multicontour seat seat contour (vehicles with multicontour seats).

 Close sliding sunroof (vehicles with sliding sunroof or panoramic sliding sunroof).

 Close side window, leaving a small gap.

 Hearing protection

All measures are deactivated as soon as the prevailing situation is no longer evaluated as critical.

Reversible emergency tensioning retraction

The reversible emergency tensioning retraction reduces the amount of seat belt slack by tensioning the front seat belts. The driver and front passenger are held in position better in their seats so as to optimize the protective effect of the conventional restraint equipment. Depending on the situation, the seat belt is tightened with varying force and speed.

As soon as the seat belt is fastened, the belt adjuster reduces the existing slack by tightening the seat belts. The function is available for the front seats. It can be switched on and off via the vehicle settings controls.

Seat adjustment (vehicles with seat adjustment with memory function)

The effectiveness of conventional restraint equipment is greater when the vehicle occupant is moved to an appropriate seated position. For this reason, the preventive occupant protection system commands the adjustment of the front passenger seat and, in the case of multicontour seats (vehicles with multicontour seats), the adjustment of the seat contour. An active setting, if given, is interrupted.

The following settings are made:

 The front passenger seat is moved to a favorable position in terms of safety. Depending on the current seat position, the following adjustments are made:

 Backrest inclination

 Seat height

 Seat fore/aft position

 Seat inclination

 The side inserts in the multicontour seats (vehicles with multicontour seats) are inflated. This fixes the occupant in the center of the seat.

 The air cushions of the lumbar supports (vehicles with multicontour seat) are deflated. The occupant thus sits lower in the seat.

The adjustments are ended when the optimum seat position is reached. After completion or cancellation of the measure, the front passenger seat remains in the held position.

Close sliding sunroof (vehicles with sliding sunroof or panoramic sliding sunroof).

The sliding sunroof is closed completely by the preventive occupant protection system if it was open in the tilt position previously. If the sliding sunroof was previously open in the sliding direction, it is closed leaving a small gap. If the vehicle rolls over, for example, this ensures that no objects can penetrate into the vehicle interior and that no limbs of the occupants can protrude from the vehicle. After completion or cancellation of the measure, the sliding sunroof remains in the held position.

Close side windows, leaving a small gap

The side windows are closed leaving a gap of approx. 50 mm. This ensures that, during an accident, no objects can penetrate into the vehicle interior and that no limbs of the occupants can protrude from the vehicle. Furthermore, it allows the smoke particles arising from the activation of the restraint equipment to disperse quickly. Active window lowering (automatic) or a manual setting is aborted. When the side windows are closing, the automatic reversing function is active. If required, the closing process is reversed. After completion or cancellation of the measure, the side windows remain in the held position.

Hearing protection

During an accident, noises with high sound-pressure levels can be generated that damage the hearing. The output of a noise signal via the speaker system shortly before a possible accident prepares the occupants' hearing for the expected accident noise. The noise signal can trigger a natural reflex in the vehicle occupants that protects the eardrum against high sound pressure levels. This can reduce the harm to the occupants' hearing.

	Function schematics
	Trigger preventive occupant protection system, function schematic	Model 213, 238, 257, 290 as of model year 2021	PE91.40-P-2500-97D
		Model 118, 177, 247 with code 299 (PRE-SAFE)	PE91.40-P-2500-97A
		Model 167, 293	PE91.40-P-2500-97B
	Subsystems
	Rear end collision warning system, basic function	Model 118, 177, 247 with code 23P (Drive package) with code 299 (PRE-SAFE) Model 167 with code 23P (Drive package) Model 167 with code P20 (Driving assistant package Plus) Model 213, 238, 257, 290 as of model year 2021 with code 23P (Drive package) Model 213, 238, 257, 290 as of model year 2021 with code P20 (Driving assistant package Plus) Model 293 with code 23P (Drive package)	GF91.40-P-1002A
	Side impact preventive occupant protection system, basic function	Model 167 with code 292 (PRE-SAFE® Impulse Side) Model 213, 238, 257, 290 as of model year 2021 with code 292 (PRE-SAFE® Impulse Side)	GF91.40-P-1005A
	Further basic functions
	Traffic area monitoring, basic function		GF54.71-P-1000A
	Actuate window lifter, basic function		GF67.39-P-9900A
	Open/close sliding sunroof, basic function	Model 118, 177, 247 with code 299 (PRE-SAFE) with code 413 (Panoramic sliding sunroof/glass roof) Model 167 with code 413 (Panoramic sliding sunroof/glass roof) Model 167 with code 414 (Electric sunroof, glass version) Model 213, 238, 257, 290 as of model year 2021 with code 414 (Electric sunroof, glass version) Model 213, 238 as of model year 2021 with code 413 (Panoramic sliding sunroof/glass roof) Model 293 with code 413 (Panoramic sliding sunroof/glass roof) Model 293 with code 414 (Electric sunroof, glass version)	GF77.20-P-9901A
	Speaker system, basic function		GF82.62-P-9900A
	Front seat electrical seat adjustment, basic function	Model 118, 177, 247, 293 with code 241 (Left electric adjustable driver's seat with memory) with code 299 (PRE-SAFE) Model 118, 177, 247, 293 with code 242 (Right electric adjustable driver's seat with memory) with code 299 (PRE-SAFE) Model 118, 177, 247, 293 with code 275 (Memory Package (driver's seat, steering column and mirror)) with code 299 (PRE-SAFE) Model 167 Model 213, 238, 257, 290 as of model year 2021 with code 275 (Memory Package (driver's seat, steering column and mirror)) Model 293 with code 221 (Electrically adjustable left driver seat) Model 293 with code 222 (Electrically adjustable right driver seat)	GF91.10-P-9900A
	Multicontour seat,basic function	Model 118, 177, 247 with code 299 (PRE-SAFE) with code 409 (Left and right front multicontour seat) Model 167 with code 399 (Front multicontour seat with massage function) with code 406 (Multicontour rear seat) Model 213, 238, 257, 290 as of model year 2021 with code 432 (Dynamic seats left and right) Model 293 with code 399 (Front multicontour seat with massage function) with code 409 (Left and right front multicontour seat)	GF91.25-P-9900A
	Control units
	Electronic Stability Program control unit, basic function		GF42.45-P-9890A
	Reversible belt tensioner, basic function		GF91.40-P-9890A