Restraints - Design and Function: Other Volvo V70 II

Airbag module

A new type of pyrotechnic powder charge is used (60 g). It is a more environmentally friendly alternative than natriumaziden which was used previously.

The shape and mounting of the airbag are completely new. The bracket for operating the horn is now secured to the airbag module which results in less play and gives a better positioning.

The airbag module is available in three different colors and six different versions, depending on the keypad. The airbag module is available with the following keypad combinations

1. without keypads
2. with cruise control keypad
3. with audio keypad
4. with audio and carphone keypad
5. with audio and cruise control keypad
6. with audio, carphone and cruise control keypad.

The air bag is approximately 67 liters when deployed.

A new type of connector with secondary snap lock is used to connect the airbag to the SRS system.

Scheme 86

Explanation of illustration

A. Charge 1 is activated. The pressure corresponds to approximately 70% of the maximum pressure.

B. Charge 2 is activated based on a delay calculated by the SRS control module.

X. Time (ms) between the activation of stage 1 and 2.

Y. Collision energy.

Activation of airbags and seat belt tensioners

The seat belt tensioners and airbags are activated in the following sequence, depending on the force of the collision and whether or not the driver and/or passenger is wearing a seat belt

1. The trigger threshold depends on the force of the impact. Level 1 = "low" impact force, Level 5 = "high" impact force
2. The three rear seat belt tensioners are activated simultaneously, always at trigger threshold 3. This is irrespective of whether anybody is sitting on the rear seats or whether or not they are wearing seat belts
3. The SRS control module calculates the collision process. The force of impact is included in these calculations, which enables the control module to calculate the trigger threshold that will be reached. The components are then activated in the sequence outlined above.

Scheme 87

System Components

1. SIPS module, driver's seat
2. Driver's airbag
3. SRS lamp
4. Passenger Airbag
5. SIPS, passenger seat
6. Side impact sensor, B-post on right-hand side
7. Seat belt tensioner, B-post on right-hand side
8. SRS module
9. Central electronic module (CEM)
10. Seat belt buckle, right front seat
11. Side impact sensor, C-post on right-hand side
12. IC, right-hand side
13. Seat belt tensioner, right-hand side in rear seat
14. Seat belt tensioner, rear center seat
15. Seat belt tensioner, left-hand side in rear seat
16. IC, left-hand side
17. Side impact sensor, C-post on left-hand side
18. Seat belt buckle, left front seat
19. Seat belt tensioner, B-post on left-hand side
20. Side impact sensor, B-post on the left-hand side.

Scheme 88

Inflatable Curtain (IC)

The inflatable curtain (IC) is standard in all markets.

The curtain reduces the risk of head injuries to both front and rear seat occupants in the event of both side impact and multi-point impact (when the car is subjected to different types of impact). The curtain protects occupants from

1. hitting their heads on the car interior.
2. hitting their heads on something the car has collided with, for example a post.
3. heads being forced out of the side windows.

The curtain consists of two inflatable protective curtains located in the edges of the roof on each side of the car. The curtain shields the upper section of the car interior, from the A to the C-posts.

The curtain is manufactured using "one piece woven technology" - this means that the curtain is woven in one piece with channels in predetermined places.

In non-deployed position, the curtain is packed in a zigzag shape inside a plastic casing which in turn is located inside the car's headlining.

The gas cartridge for curtain deployment is located in the roof at the C-posts. The gas consists of a mixture of Argon (95%) and Helium (5%). During inflation, a pyrotechnic charge (3 g of powder) is used to heat and thereby expand the gas mixture.

Helium is only used to be able to carry out leak tracing on the curtain during manufacture.

The curtain deploys and is inflated to full capacity in approximately 25 ms. In the edges between the different channels there are small outlets for the gas. The outlets are shaped so that the curtain empties slowly. This takes approximately 3 seconds. This gives occupants protection over a longer period of time, during for example multiple collisions or if the car overturns.

When fully inflated, the thickness of the curtain is approximately 70 mm (2.76 in).

The carefully controlled release means that occupant's heads are protected in the best possible way. The curtain can absorb up to 75% of the energy generated at impact.

In the headlining is a device that folds the corners of the headlining out of the way during deployment of the curtain.

Both the acceleration sensors in the B and C-posts and the SRS module are used to determine if the side airbags and inflatable curtain (IC) should be deployed. Activation is governed by acceleration and point of impact. For example a collision at a 90 degree angle at a speed in excess of 25 Km/h (16 mph).

Scheme 89

Front seat belts

Seat belts with pyrotechnic seat belt tensioners are standard in all markets.

The seat belts have integral strength limiters. In Nordic markets cars are being produced both with and without passenger airbags. If there is no passenger airbag, the passenger seat belt is used without a strength limiter.

The pyrotechnic pipe has a stroke of 150 mm (5.91 in) with an effective seat belt tension of 100 mm (3.94 in).

A new type of connector with a spring lock is used to connect the pyrotechnic pipe to the SRS system.

For USA and Canada markets the passenger seat-belt is an ARL belt.

Rear seat belts

Seat belts with pyrotechnic seat belt tensioners are standard in all markets.

The seat belt (inertia) reel mounting has holes for a bolt secured in the bodywork and for a locating pin.

A new type of connector with a spring lock is used to connect the pyrotechnic pipe to the SRS system.

The pyrotechnic pipe has a stroke of 100 mm (3.94 in) with an effective seat belt tension of 70 mm (5.92 in).

For USA and Canada markets the rear seat-belts are ARL belts.

Scheme 90

Side collision sensors

The sensors for side impact detection are located on the of the B and C posts. This location allows quick (early) reaction time in the event of side impact.

The sensors on the B and C-posts are not interchangeable/identical. The B-post sensor is gray and the C-post sensor is black (different collision parameters).

The sensors are directly connected to the SRS module.

The side impact sensors are "independent units." The sensor is made up of a micro processor with an acceleration sensor and interface.

The side impact sensor spontaneously carries out internal diagnoses and registers with the SRS unit that the sensor is fault free.

The side impact sensor registers with the SRS unit if a collision impulse is detected with sufficiently high energy content. The SRS unit then checks whether it also senses the collision impulse, in which case it triggers the safety equipment. It is the SRS module that determines if, when and which safety equipment should be deployed.

SRS module

The SRS unit continually transmits diagnostic pulses to all SRS components. The diagnostic pulses check that there are no wiring short-circuits or other faults in the SRS system. In the event of a fault the SRS lamp lights. (The SRS lamp also lights briefly (approximately 7 s) when the ignition is switched on. During this time the SRS module starts up the side impact sensors, runs self diagnostics and diagnostics of other SRS components and charges the SRS system's ignition capacitor).

The bracket for the module must be rigidly secured in the body and welded (with as high resonance frequency as possible >300 Hz).

The SRS module can still deploy up to 10 seconds after any power failure.

In the event of a collision, the SRS module transmits a signal so that the central locking system opens (if locked), passenger compartment lighting switches on, hazard warning signal flashers operate and fuel supply is shut off.

Scheme 91

Fault indication

The driver is warned in a number of ways via the combined instrument panel if any fault occurs in the SRS system

1. SRS warning lamp and text in the display
2. The general warning lamp lights up in red and text in the display
3. The general warning lamp lights up in orange and text in the display.

A VIDA station must be connected to the car data link connector (DLC) in order for a fault source to be identified.

The air bag is inflated by a gaseous mixture consisting of Argon, Helium and oxygen. The gas cylinder is initiated by a pyrotechnic charge (12 g) which also contributes to the gas development. At ignition, the charge warms up the gaseous mixture which then expands to a greater volume, creating higher pressure.

Helium is only used to carry out leak tracing on the airbag during manufacture.

The passenger side airbag is standard for all markets except for the Nordic markets where it is an option.

The volume of a deployed airbag is approximately 150 liters.

Scheme 92

SIPS airbag

The SIPS airbag with electronic ignition is standard on both front seats. Bag volume is approximately 10 liters.

The airbag is inflated by a gas cartridge located inside the bag. The gas consists of a mixture of Argon (95%) and Helium (5%). (Helium is only used to be able to carry out leak tracing on the airbag during manufacture). The airbag also contains a pyrotechnic powder charge to heat, and thereby expand the gas mixture.

The SIPS airbag is triggered approximately 3 ms after impact. The bag reaches its operational pressure after 10 ms. Pressure in the bag begins to fall 25 ms after impact.

The SIPS bag volume has been increased in comparison to the previous version. This results in the rib cage being covered further forward and pressure is maintained for a longer period. This combination provides better protective qualities.

A new type of connector with a spring lock is used to connect the SIPS airbag to the SRS system. The connector is yellow.

The SRS system runs diagnostics on the SIPS bag up to the ignition wire.

Scheme 93

WHIPS seat

The aim of WHIPS (Whiplash Protection System) is to reduce the risk of whiplash injuries in the event of collision from the rear. The system is designed for maximum performance at low speed collisions. The majority of whiplash injuries occur during accidents at a speed of 10-20 km/h (6-12 mph).

WHIPS seats have a normal folding function, similar to the passenger seats in the present 850 series. However the mechanism has been modified to take a WHIPS deployment mechanism for the backrest in both joints (a pendulum function with a suppressing deformation element).

The mechanism consists of the following components

1. Mounting plate for seat backrest
2. Heat plate with window (23)
3. Link (25)
4. Deformation element (24)
5. Seat anchor plate (23)
6. Indicator pin (26)
7. Damper spring

WHIPS seats are standard for both front seats.

In relation to current seats, WHIPS seats backrests are more resistant to twisting because of the greater lower tube dimension while the upper section of the backrest is shaped like a closed beam. The springs for the backrest back pad are equipped with compression limiters (22)

In order to protect the occupants' heads during an accident, the head restraint is now in a more forward position (the same position as in the P90). The distance between the head restraint struts has also been reduced.

The deployment mechanism begins to operate in the event of a collision speed of approximately 14 to 18 km/h (9 - 11 mph), depending on the weight of the occupant (the collision speed at which the indicator pin shears off).

Scheme 94

In the event of a collision from the rear, the seat moves forward, thereby pressing the backrest against the occupant. The system then activates, going through two clearly defined phases.

Illustration A

At activation the seat back moves first mainly backward in upright position, whereby the body is secured in a balanced way. The distance of this parallel movement is approximately 50 mm (1.97 in). At activation, the indicator pin (26) shears off.

Illustration B

Instead of the occupant now being thrown forward, as in a traditional seat, the backrest now begins to angle backwards (up to 15 degrees). This is achieved using a deformation element (a link with set deformation qualities, 24) which collapses and therefore gently brakes movement (absorbs energy during the crash sequence). The compression limited springs distributes force evenly throughout the entire spine to avoid pressure points which often previously resulted in S-curvatures to the spine.

Because lesser collisions from the rear may also activate the system, a repair kit has bee produced. The WHIPS repair kit consists of

1. Deformation elements (x 2)
2. Indicator pins (x 2)
3. Return springs (x 2)
4. Link washer (x 2)
5. Pivot bushing (x 2)
6. Pivot shaft with nut (x 2)
7. Notched washer

See Design

Downloading software and replacing the control module

See Downloading software and replacing the control module

See Function

See Downloading software and replacing the control module

See Function