DE102011117940A1 - Airbag device for motor vehicle, has inflatable gas bag provided with two chambers, which are separated from each other, where gas generator is provided for inflating former chamber - Google Patents

Abstract

The airbag device (2) has an inflatable gas bag (4) provided with two chambers (24,26), which are separated from each other. A gas generator (8) is provided for inflating the former chamber. Another gas generator (10) is assigned to the latter chamber. The latter chamber is charged with the pressure by the latter gas generator under generation of an outlet opening in the gas bag. The gas is discharged from the former chamber in surroundings (48).

Description

Technical area

The technical field relates to airbag devices with an inflatable airbag and a gas generator for inflating the airbag.

background

Airbag devices for motor vehicles are known from the prior art. These airbag devices have a folded, inflatable airbag, to which a triggerable gas generator is assigned, which serves to generate a gas that explodes explosively, which ultimately causes the airbag to deploy or inflate. The known gas bags are not completely closed as a rule, but rather have outlet openings, via which the gas can be discharged into the environment within the gas bag. The size of the outlet openings determines or sets the damping of the system.

In the case of the above-described airbag devices known from practice, there is the disadvantage that a relatively large amount of gas has to be kept by the gas generator in order to allow rapid and complete inflation and deployment of the gas bag. The relatively large amount of gas to be kept in turn requires a particularly large and heavy gas generator for the airbag device.

It is therefore an object of the present invention to provide an airbag device which is on the one hand particularly space-saving and on the other hand particularly lightweight.

This object is achieved by the features specified in claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

Summary

An embodiment of the invention relates to an airbag device with an inflatable airbag. The wall of the gas bag is in this case preferably formed by a tissue. In the gas bag, a first chamber and a second chamber separate from the first chamber is formed. In addition, the airbag device has a first gas generator for inflating the first chamber. Furthermore, a second gas generator is provided, which is assigned to the second chamber, wherein the second gas generator can be triggered offset in time to the first gas generator. Thus, the second chamber can be pressurized by the second gas generator. In this case, the second gas generator or the pressure which can be generated by the second gas generator within the second chamber is matched to the second chamber or the wall surrounding the second chamber such that an outlet opening in the gas bag is generated by the pressurization of the second chamber. This is preferably done by a partial destruction of the gas bag, so for example by tearing or tearing of the gas bag or attached parts. Not only the gas from the second chamber, but also the gas from the first chamber can be discharged into the environment through the outlet opening, so that the damping properties of the gas bag were changed by generating the outlet opening.

The airbag device has the advantage that a relatively small amount of gas must be kept in order to inflate the gas bag quickly and completely, so that the first gas generator can be made relatively small and lightweight. This is due to the fact that initially only the first chamber can be inflated by the first gas generator, without the gas is discharged during deployment and inflation of the gas bag via the outlet opening to the environment, especially since the outlet has not yet been created. This outlet opening is rather generated with a time delay, after the first chamber is already largely inflated and the gas bag is thus largely unfolded by the second gas generator is triggered with a time delay and generated by the increased pressure within the second chamber, the outlet through which the gas now from the first chamber can be discharged into the environment. Analogously, a replacement for a two-stage gas generator is provided by the invention, which would ignite in two stages. However, since such two-stage gas generators are relatively expensive, a simplified solution is created by the inventive arrangement of two gas generators. It should also be mentioned in this context that the second gas generator for pressurizing the second chamber may be a relatively small gas generator, especially since this only has to provide a small amount of gas in order to ensure the generation of the outlet opening. For this reason, it also makes sense to make the volume of the second chamber smaller, preferably significantly smaller, than the volume of the first chamber.

In a preferred embodiment of the airbag device according to the invention, an outer wall separating the second chamber from the environment is provided with a cover part which can be torn off or torn open by the pressurization of the second chamber to produce the outlet opening. It is in this embodiment Preferably, when the cover is torn or torn open by the pressurization of the second chamber along a predetermined tear line, particularly preferably along a tear seam.

In an advantageous embodiment of the airbag device according to the invention, the cover part is formed by a fabric and / or a sheet of plastic. If the cover part is formed by a fabric, then it is preferable if the tissue used is that which is also used for the inflatable gas bag. In other words, the same fabric should be used for the fabric as for the gas bag.

In a particularly preferred embodiment of the airbag device according to the invention, an intermediate wall separating the first chamber from the second chamber is provided, whereby a passage opening in or on the intermediate wall can be generated by the pressurization of the second chamber, via which the gas from the first chamber to the outlet opening is feasible.

In a further particularly preferred embodiment of the airbag device according to the invention, the intermediate wall has a cover section, which can be torn off or torn open by the pressurization of the second chamber to produce the passage opening. In this embodiment, too, it is preferred if the covering section can be torn off or torn open along a predetermined tear line, particularly preferably along a tear seam.

In order to ensure to a particularly high degree that the gas from the first chamber via the passage opening and the outlet opening can be discharged into the environment, the cover is coupled in a particularly advantageous embodiment of the airbag device according to the invention with the cover. This has the consequence that the tearing or tearing of the cover causes equally a tear or tearing of the cover portion of the intermediate wall. The coupling is preferably carried out via the tear seam. For example, the cover part of the outer wall and the cover section of the intermediate wall can have a common tear seam or a common tear seam section.

In order to enable a particularly simple production of the gas bag with the two chambers, the intermediate wall is formed by a fabric attached to the inside of the gas bag to produce the second chamber. Alternatively, the intermediate wall is formed by a fabric attached to the outside of the gas bag to produce the second chamber. However, the former alternative is preferred. Regardless of the chosen alternative, it is advantageous in this embodiment, when the fabric is sewn to the inside or outside of the gas bag. Also, the sheet used is particularly preferably a woven fabric. The fabric may correspond to the fabric of the gas bag, in other words, when using a fabric as a sheet, the same fabric should be used as that used for the gas bag.

In a further advantageous embodiment of the airbag device according to the invention, the fabric is attached to the inside or outside of the airbag, preferably on the inside of the airbag, to produce a cover region, optionally also the cover section, associated pressure region and an elongated conduit region of the second chamber. On the one hand, the line region opens into the pressure region and, on the other hand, has an inlet opening for the second gas generator, via which the gas of the second gas generator can flow into the second chamber in order to pressurize it. The elongated line region also makes it possible to supply a pressure region arranged relatively far from the second gas generator and thus also the generation of an outlet opening in a section of the gas bag far away from the gas generator. In this case, it is preferred if the line region has a smaller cross section than the pressure region.

In order to reduce the manufacturing costs and the weight of the inflatable airbag, the intermediate wall is formed in a further particularly preferred embodiment of the airbag device according to the invention of a tether for limiting the expansion of the unfolded airbag. In this way, an existing anyway within the gas bag tether to restrict the expansion of the unfolding or unfolded airbag receives another function, namely the formation of the intermediate wall, so that here no additional material must be provided. In this embodiment, it is preferred if the ratio of the length of the tether to the width of the tether is at least 5: 1, more preferably at least 10: 1. In individual cases, however, the ratio should be designed to be much larger, so in particular ratios between the length of the tether and the width of the tether have been found to make sense, which are 20: 1 or more.

As previously indicated, the amount of gas to be held by the second gas generator need not be particularly large, but rather the pressure within the second chamber that can be generated by the second gas generator is critical. To the To keep vorzuhaltende amount of gas of the second gas generator low, so that it can be made small and lightweight, the volume of the second chamber in a further particularly advantageous embodiment of the invention airbag device is at most 10%, preferably at most 5%, preferably at most 1%, of the volume the first chamber. In this case, the volume of the respective chamber is to be understood as meaning that volume of the chamber which has this volume in the case of a fully inflated or unfolded gas bag. One could therefore also speak of the maximum volume of the respective chamber.

In a further advantageous embodiment of the airbag device according to the invention, the airbag device further comprises an airbag housing for receiving the gas bag and / or the first, and possibly also the second, gas generator. In this embodiment, it is preferred if at least one further outlet opening is provided in the airbag housing, through which the gas from the first chamber and / or from the first gas generator from the airbag housing can be discharged into the environment. This further outlet opening can thus act in addition to the outlet opening in the gas bag, wherein the outlet opening in the gas bag and the outlet opening in the airbag housing have different effects on the system behavior. In this embodiment, it is further particularly preferred if the further outlet opening in the airbag housing can be selectively or / and independently of the outlet opening in the gas bag generated or opened. Thus, for example, a three- or multi-level behavior of the system would be feasible.

In a further advantageous embodiment of the airbag device according to the invention can be generated by the second gas generator, a greater pressure within the second chamber than by means of the first gas generator in the first chamber, so that the generation of the outlet opening in the gas bag and optionally the passage opening on or in the Particularly preferably, the intermediate wall can be effected exclusively by the triggering of the second gas generator, but not by the triggering of the first gas generator. The second gas generator is preferably designed as a micro gas generator in order to arrange this space-saving can.

In a further preferred embodiment of the airbag device according to the invention, a control device is provided which interacts with the first and second gas generator in such a way that the first gas generator and the second gas generator offset in time are triggered. Thanks to the control device thus comes to the two-stage behavior of the system described above, in which the gas bag is first deployed quickly to subsequently change the damping properties by generating the outlet opening, Thus, the airbag device in this embodiment, a full replacement for airbag devices, each with a large-building and heavyweight two-stage single gas generator.

In a further advantageous embodiment of the airbag device according to the invention, a determination device is also provided for determining an accident, which cooperates with the control device in such a way that the first gas generator is triggered when an accident is detected. In this embodiment, it is preferred if further ignition decision parameters can be determined by the determination device, by means of which in conjunction with a predetermined ignition algorithm, the time offset for triggering the second gas generator can be determined in order to control the second gas generator accordingly via the control device or trigger. By incorporating further ignition decision parameters, the system can be adapted particularly precisely to the ambient conditions in order to achieve an ideal behavior of the airbag device. The further ignition decision parameters that can be determined by the determination device are particularly preferably the type of accident, that is, for example, a frontal impact, rollover, side impact or the like, the seat position, ie the position of the seat on which the vehicle occupant sits, the position of the vehicle occupant Thus, for example, its distance from the airbag device, the size of the vehicle occupant, the weight of the vehicle occupant and / or the ambient temperature to determine the ideal size of the time offset for triggering the second gas generator in conjunction with a predetermined ignition algorithm and thus the risk of injury to the To minimize vehicle occupants significantly.

Brief description of the drawings

The invention will be explained in more detail below with reference to an exemplary embodiment with reference to the accompanying drawings. Show it:

1 a schematic representation of an embodiment of the airbag device according to the invention,

2 a view of the inside of the airbag of 1 in the direction of arrow A,

3 a cross-sectional view of the conduit region of the second chamber along the section line BB of 2 .

4 the airbag device of 1 after the removal or tearing of the cover and

5 the airbag device of 4 after generating the passage opening in or on the intermediate wall.

Detailed description of the drawings

1 shows an embodiment of the airbag device according to the invention 2 for a motor vehicle, wherein the airbag device 2 is usable for both the driver side and the passenger side of the motor vehicle. The airbag device 2 has a folded, inflatable airbag 4 on that in 1 already shown in its unfolded or inflated state. The gas bag 4 is in the folded state in a stiff airbag housing 6 added. In or on the airbag housing are also a first gas generator 8th and a second gas generator 10 arranged.

The two gas generators 8th . 10 are each via a control line 12 . 14 with a control device 16 connected so that the first gas generator 8th over the control line 12 and the second gas generator 10 over the control line 14 by the control device 16 can be triggered or ignited. The control device 16 in turn is via a signal line 18 with a detection device 20 in connection, which serves to determine an accident of the motor vehicle. In addition, by the investigator 20 further Zündentscheidungsparameter determined, preferably the type of accident, the sitting position, the position of the vehicle occupant, the size of the vehicle occupant, the weight of the vehicle occupant and / or the ambient temperature, for which purpose a plurality of sensors 22 are provided, via which the detection device 20 can measure or determine said ignition decision parameters.

The gas bag 4 , which is formed by a tissue, has a first chamber 24 and one from the first chamber 24 separate second chamber 26 on. The gas bag 4 acts in such a way with the gas generators 8th . 10 together, that the first chamber 24 through the first gas generator 8th is inflatable while the second chamber 26 the second gas generator 10 is assigned, so that the pressure within the second chamber 26 through the second gas generator 10 can be increased. Here is the second gas generator 10 over the control line 14 offset in time to the first gas generator 8th by the control device 16 triggered, which will be discussed again later.

To the first chamber 24 from the second chamber 26 to separate is an intermediate wall 28 intended. In the illustrated embodiment, the intermediate wall 28 from one on the inside 30 of the gas bag 4 creating the second chamber 26 attached sheets 32 educated. Here is the sheet 32 preferably formed by a fabric which is the tissue of the gas bag 4 equals or equals the sheet 32 on the gas bag 4 was sewn on. The corresponding seam 34 is especially in the 2 and 3 shown. The fabric 32 is doing so with the inside 30 of the gas bag 4 sewed that between the inside 30 of the gas bag 4 and the sheet 32 trained second chamber 26 essentially in a pressure range 36 and an elongated conduit area 38 is divisible. The line area 38 on the one hand has an inflow opening 40 for the second gas generator 10 on the other hand, opens at his the second gas generator 10 opposite end in the printing area 36 , where the pressure range 36 preferably a larger cross section than the line area 38 having.

A cover section 42 of the fabric 32 is the print area 36 the second chamber 26 assigned. In the area of the cover section 42 is the seam 34 of the fabric 32 as a tear seam 44 trained, like this in 2 indicated by the dotted line. By the way, the seam is 34 as a permanent seam 46 trained, like this in 2 shown by the dashed line. In addition, is off 2 seen that the sheet 32 in the illustrated embodiment with the cover portion 42 at the height of the print area 36 ends, which need not necessarily be the case, as will be explained later with reference to an alternative embodiment variant.

It is also a second chamber 26 from the surroundings 48 separating outer wall 50 provided in the illustrated embodiment of the wall of the gas bag 4 is formed. The outer wall 50 consists of a part of the wall of the gas bag 4 and a cover part 52 together, a hole in the gas bag 4 closes. To the cover part 52 on the rest of the outer wall 50 to attach, is a circumferential around the hole tear seam 54 provided, which therefore acts as a predetermined tear line and preferably partly in one piece or contiguous with the tear seam 44 for attachment of the fabric 32 is trained. The cover part 52 is preferably formed by a fabric, particularly preferably by the same fabric, from which also the gas bag 4 consists. Alternatively or additionally, the cover 52 be formed by a sheet of plastic, so for example by a film or the like, although a tissue-like cover member formed 52 is preferred. How out 1 can be seen, is the cover 52 at least about the tear seam 44 with the cover section 42 the partition 28 coupled.

The second gas generator 10 is significantly smaller than the first gas generator 8th educated. This is partly due to the fact that the second gas generator 10 much less gas must hold to the second chamber 26 to fill with gas and pressurize, especially the volume of the second chamber 26 at most 10%, preferably at most 5%, particularly preferably at most 1%, of the volume of the first chamber 24 is. Nonetheless, the second gas generator is 10 designed such that within the second chamber 26 a greater pressure can be generated than with the aid of the first gas generator 8th within the first chamber 24 the case is. The second gas generator 10 is therefore formed in the illustrated embodiment as a micro gas generator.

Below are further features and the operation of the airbag device 2 with reference to the 1 to 5 described.

Should the investigator 20 determine an accident of the motor vehicle, it is issued a corresponding signal via the signal line 18 to the controller 16 , whereupon the control device 16 the first gas generator 8th over the control line 12 such that the first gas generator 8th triggered or ignited. It is therefore initially the first gas generator 8th triggered while the second gas generator 10 - As explained in more detail later - triggered in time. The first gas generator 8th thus blows the first chamber 24 on, like this in 1 can be seen, so that the gas bag 4 quickly and largely completely unfold without removing gas from the chamber 24 through the previously mentioned hole in the gas bag 4 can escape, especially the said hole through the cover 52 and the cover section 42 the partition 28 is covered.

In addition, the investigator determines 20 over the sensors 22 Further ignition decision parameters, ie the type of accident, the sitting position, the position of the vehicle occupant, the size of the vehicle occupant, the weight of the vehicle occupant and / or the ambient temperature, and transmits them to the control device 16 which, based on the Zündentscheidungsparameter in conjunction with a given ignition algorithm the most meaningful time offset for triggering the second gas generator 10 determined. Once the period of time after the triggering of the first gas generator 8th reaches or exceeds the determined time offset, issued a control signal via the control line 14 from the controller 16 to the second gas generator 10 which is then triggered.

That of the second gas generator 10 generated gas flows over the inlet opening 40 in the second chamber 26 along the line area 38 into the printing area 36 , creating the second chamber 26 is pressurized. The pressure in the second chamber 26 is so large that the cover 52 along the tear seam 54 tear or tear and out into the environment 48 is urged, as in 4 is indicated. Consequently, the aforementioned hole in the outer wall becomes 50 of the gas bag 4 released, which therefore an outlet opening 56 in the gas bag 4 formed. In addition, the pressurization in the second chamber 26 so large that the cover section 42 the partition 28 creating a passage opening 58 along the tear seam 44 is torn or torn, which thus forms a predetermined tear line. About this passage opening 58 can the gas from the first chamber 24 to the outlet opening 56 be guided, through which the gas from the first chamber 24 in the nearby areas 48 can be discharged, wherein the cover section 42 through the outlet opening 56 is pushed outward, as in 5 can be seen.

With the staggered generation of the outlet opening 56 is the damping behavior of the airbag device 2 or of the gas bag 4 changed, so that a two-stage system is provided, which makes a large-scale two-stage single gas generator dispensable.

Like from the 1 . 4 and 5 can be seen in the airbag housing 6 at least one further outlet opening 60 be provided, through which the gas from the first chamber 24 or from the first gas generator 8th from the airbag housing 6 in the nearby areas 48 can be dissipated. These - not in the gas bag 4 self-planned - further outlet opening 60 may preferably be optional and / or independent of the outlet opening 56 in the gas bag 4 be created to possibly even create a three- or multi-stage system.

As already indicated above, the sheet must 32 not already at the height of the print area 36 with the cover section 42 end up. Thus, in the figures, an alternative embodiment variant further indicated by dashed lines. In this embodiment variant, the intermediate wall 28 from a tether 62 for limiting the expansion of the unfolded or unfolding gas bag 4 educated. The tether 62 extends in this embodiment variant with an extension section 64 over the cover section 42 out to other places permanently with the inside 30 of the gas bag 4 connected, which in the present example via a permanent seam 66 should be done. The ratio of the length of the tether 62 to whose in 3 indicated width b is at least 5: 1, more preferably at least 10: 1 or at least 20: 1.

Although not shown in the two embodiments described above, it is alternatively possible, the outer wall 50 from one on the outside 68 of the gas bag 4 to form fastened sheets. In this case, the intermediate wall would 28 correspondingly from the wall of the gas bag 4 educated. Incidentally, the foregoing statements apply analogously.

Since only one or more exemplary embodiments have been described above, it should be understood that in principle a variety of variations and variations are possible. It should be further understood that the described embodiments are merely examples that do not limit the scope, applicability, or construction. Rather, the summary and the described embodiments merely constitute a practical guide for the person skilled in the art, on the basis of which the person skilled in the art can arrive at at least one exemplary embodiment. It will be understood by those skilled in the art that various changes may be made in the function and arrangement of the elements described with reference to the exemplary embodiments described herein without departing from the scope of the appended claims and their equivalents.

LIST OF REFERENCE NUMBERS

2

airbag device

4

airbag

6

airbag housing

8th

first gas generator

10

second gas generator

12

control line

14

control line

16

control device

18

signal line

20

determining device

22

sensor

24

first chamber

26

second chamber

28

partition

30

inside

32

sheet

34

seam

36

pressure range

38

management area

40

inflow

42

cover

44

tear seam

46

permanent seam

48

Surroundings

50

outer wall

52

covering

54

tear seam

56

outlet

58

Through opening

60

further outlet opening

62

tether

64

extension section

66

permanent seam

68

outside

b

width

Claims (14)

Airbag device ( 2 ) with an inflatable airbag ( 4 ), which has a first chamber ( 24 ) and one of the first chamber ( 24 ) separate second chamber ( 26 ), a first gas generator ( 8th ) for inflating the first chamber ( 24 ) and one to the first gas generator ( 8th ) releasable, the second chamber ( 26 ) associated second gas generator ( 10 ), the second chamber ( 26 ) by the second gas generator ( 10 ) producing an outlet opening ( 56 ) in the gas bag ( 4 ) is pressurized, through which the gas from the first chamber ( 24 ) in the nearby areas ( 48 ) is dissipatable. Airbag device ( 2 ) according to claim 1, wherein a second chamber ( 26 ) from the surroundings ( 48 ) separating outer wall ( 50 ) with a cover ( 52 ) provided by the pressurization of the second chamber ( 26 ) creating the outlet opening ( 56 ), preferably along a predetermined tear line, particularly preferably a tear seam ( 54 ), can be torn off or torn open. Airbag device ( 2 ) according to claim 2, wherein the cover part ( 52 ) is formed by a tissue, preferably the airbag fabric, or a plastic sheet. Airbag device ( 2 ) according to one of claims 1 to 3, in which a first chamber ( 24 ) of the second chamber ( 26 ) separating partition ( 28 ) is provided, wherein the pressurization of the second chamber ( 26 ) a passage opening ( 58 ) in or at the intermediate wall ( 28 ) is generated, via which the gas from the first chamber ( 24 ) to the outlet opening ( 56 ) is feasible. Airbag device ( 2 ) according to claim 4, wherein the intermediate wall ( 28 ) a cover section ( 42 ), which by the pressurization of the second chamber ( 26 ) creating the passage opening ( 58 ), preferably along one Tear line, particularly preferably a tear seam ( 44 ), can be torn off or torn open. Airbag device ( 2 ) according to claim 5, wherein the cover section ( 42 ) with the cover part ( 52 ), optionally via the tear seam ( 44 ) is coupled. Airbag device ( 2 ) according to one of claims 4 to 6, in which the intermediate wall ( 28 ) of one on the inside ( 30 ) or the outer wall ( 50 ) of one on the outside ( 68 ) of the gas bag ( 4 ) to produce the second chamber ( 26 ), preferably sewn, flat structures ( 32 ), particularly preferably a fabric, optionally the gas bag fabric, is formed. Airbag device ( 2 ) according to claim 7, wherein the sheet ( 32 ) producing a cover part ( 52 ), possibly also the cover section ( 42 ), associated print area ( 36 ) and an elongated line region ( 38 ) of the second chamber ( 26 ) on the inside or outside ( 30 . 68 ) of the gas bag ( 4 ), the line area ( 38 ) on the one hand into the printing area ( 36 ) and on the other hand an inflow opening ( 40 ) for the second gas generator ( 10 ) having. Airbag device ( 2 ) according to one of claims 4 to 8, in which the intermediate wall ( 28 ) from a tether ( 62 ) for limiting the expansion of the unfolded gas bag ( 4 ), wherein the ratio of the length of the tether to the width (b) of the tether is preferably at least 5: 1, more preferably at least 10: 1. Airbag device ( 2 ) according to one of the preceding claims, in which the volume of the second chamber ( 26 ) at most 10%, preferably at most 5%, preferably at most 1%, of the volume of the first chamber ( 24 ) is. Airbag device ( 2 ) according to one of the preceding claims, comprising an airbag housing ( 6 ) for receiving the gas bag ( 4 ) and / or the first, and possibly also the second, gas generator ( 8th . 10 ), wherein in the airbag housing ( 6 ) preferably at least one further, more preferably optionally or / and independently of the outlet opening ( 56 ) in the gas bag ( 4 ) producible, outlet opening ( 60 ) is provided, through which the gas from the first chamber ( 24 ) or from the first gas generator ( 8th ) from the airbag housing ( 6 ) in the nearby areas ( 48 ) is dissipatable. Airbag device ( 2 ) according to one of the preceding claims, in which by means of the second gas generator ( 10 ) a greater pressure within the second chamber ( 26 ) than with the aid of the first gas generator ( 8th ) in the first chamber ( 24 ) is generated, wherein the second gas generator ( 10 ) is preferably designed as a micro gas generator. Airbag device ( 2 ) according to any one of the preceding claims, in which a control device ( 16 ) provided in such a way with the first and second gas generator ( 8th . 10 ) cooperates, that first the first gas generator ( 8th ) and temporally offset the second gas generator ( 10 ) is triggered. Airbag device ( 2 ) according to claim 13, in which a determination device ( 20 ) is provided for determining an accident, which with the control device ( 16 ) cooperates, that the first gas generator ( 8th ) can be triggered upon determination of an accident, wherein preferably further ignition decision parameters, particularly preferably the accident type, the sitting position, the position of the vehicle occupant, the size of the vehicle occupant, the weight of the vehicle occupant and / or the ambient temperature, by means of the determination device ( 20 ) can be determined on the basis of which, in conjunction with a predetermined ignition algorithm, the time offset for triggering the second gas generator ( 10 ) can be determined.

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