Knee airbag arrangement for a vehicle with an airbag module and method for triggering the knee airbag arrangement

Abstract

Knee airbag arrangement (1) for a vehicle (10) with an airbag module (2), wherein the airbag module (2) comprises: - a first airbag (3.1), which is designed as a knee airbag for a vehicle occupant (20) to be deployed in the event of a vehicle collision into a first deployment space (R1) between a lower region (11.1) of an instrument panel (11) and the knees (20.1) of the vehicle occupant (20), wherein the first deployment space (R1) is created when a first vehicle seat longitudinal position (I') of a vehicle seat (12) allows the vehicle occupant (20) to assume a usual vehicle seat longitudinal position (I), - a second airbag (3.2) which, in the event of a collision, can be deployed into a second deployment space (R2) between the lower region (11.1) of the instrument panel (11) and the feet (20.2) of the vehicle occupant (20), the second deployment space (R2) being created when a second vehicle seat longitudinal position (II') of the vehicle seat (12) is displaced rearwardly relative to the first vehicle seat longitudinal position (I') and allows the vehicle occupant (20) to assume a resting or comfortable position in the occupant seat (II), and - an inflation device (4) for inflating the first or second airbag (3.1, 3.2).

Description

[0001] The invention relates to a knee airbag arrangement for a vehicle with an airbag module and a method for triggering the knee airbag arrangement.

[0002] A knee airbag arrangement is known, for example, from DE 603 07 582 T2, which comprises an airbag that deploys in front of the legs of a vehicle occupant and is designed such that the airbag deploys essentially only in a total of two areas: in front of the ankles or insteps and in front of the knees of the vehicle occupant's legs. This deployment process is controlled such that the airbag deploys first in front of the ankles or insteps and then in front of the knees, thereby preventing a forward movement of the knees, thighs, and lumbar region. In this known knee airbag arrangement, the airbag restrains the ankles or insteps early on, thereby preventing the ankles or insteps from striking an instrument panel or the like.

[0003] US 2007 / 0 296 192 A1 describes a vehicle occupant restraint device with multiple components. These components include a steering wheel airbag, a knee restraint device, an airbag device arranged in the footwell area, and another airbag which deploys between the two knees of a vehicle occupant in the event of a vehicle collision. The airbag device arranged in the footwell area comprises a front airbag and a rear airbag relative to the feet of the vehicle occupant. The front airbag is arranged below an instrument panel of the vehicle and deploys towards the feet of the vehicle occupant, while the rear airbag is on the underside of the seat part orThe knee restraint device is arranged on the seat cushion of the vehicle occupant's vehicle seat and also unfolds toward the vehicle occupant's feet, so that the vehicle occupant's foot area is clamped between the two airbags when deployed. The knee restraint device consists of a cushion that extends from the instrument panel at the height of the vehicle occupant's knees and is pressed against the vehicle occupant's knees in the event of a vehicle collision.

[0004] DE 196 28 837 A1 discloses an occupant restraint device designed as an airbag, which has several superimposed chambers. A position sensor determines the position of a vehicle occupant, and in the event of a vehicle collision, the airbag chambers are fully, partially, or not at all, depending on the occupant's position.

[0005] An occupant restraint device according to DE 10 2012 011 036 A1 comprises a knee airbag that can be deployed between an instrument panel of a vehicle and the legs of a vehicle occupant. This known occupant restraint device further comprises a device for qualifying the body type of the vehicle occupant, an activation unit for selectively releasing airflow openings of the knee airbag, and a control unit that actuates the activation unit depending on the qualification of the body type of the vehicle occupant.

[0006] Furthermore, this DE 603 07 582 T2 proposes a knee airbag arrangement with two airbags, namely an ankle airbag that deploys only in front of the ankles or insteps, and a knee airbag that deploys only in front of the knees of the vehicle occupant. This is intended to achieve a greater degree of flexibility in the arrangement of the airbags.

[0007] Finally, US 5 803 491 A describes a switch-off device for an occupant restraint device of a vehicle, with which the occupant restraint device is deactivated or activated depending on the position of a vehicle seat.

[0008] In autonomous vehicles, the driver can adopt a different position in autonomous driving mode than in non-autonomous driving mode. This position relates both to the sitting position or posture on the vehicle seat and to the vehicle seat position in the longitudinal direction of the vehicle. In autonomous driving mode, the driver can therefore move into a comfortable resting or comfort position in which the vehicle seat is shifted against the direction of travel compared to a vehicle seat position in which the driver is in a usual sitting position required for driving the vehicle. If the vehicle seat is in a vehicle seat position in which the driver can adopt a usual sitting position for driving the vehicle, there is only a small distance between the driver's knees and a lower area of the vehicle's instrument panel. If, on the other hand, the driver is in the resting or comfort position described above.In the comfort position, in which the vehicle seat is moved backwards, there is a large distance to the driver's knees and feet from the lower part of the instrument panel.

[0009] The known knee airbag arrangement according to the state of the art cannot ensure sufficient impact protection for a vehicle occupant, both in their resting or comfort position and in the occupant seating position required for driving the vehicle.

[0010] The object of the invention is to provide a knee airbag assembly for a vehicle that ensures sufficient impact protection, particularly for the lower extremities of the vehicle occupant, when the vehicle occupant is in a resting or comfortable position, while simultaneously ensuring the coupling of the vehicle occupant to the instrument panel in the event of a vehicle collision when the vehicle occupant is in a normal sitting position. Furthermore, the object of the invention is to provide a method for deploying the knee airbag assembly according to the invention.

[0011] The first-mentioned object is achieved by a knee airbag arrangement having the features of patent claim 1.

[0012] Such a knee airbag arrangement for a vehicle with an airbag module is characterized according to the invention in that the airbag module comprises: - a first airbag, which is designed as a knee airbag for a vehicle occupant to be deployed in the event of a vehicle collision into a first deployment space between a lower region of an instrument panel and the knees of the vehicle occupant, wherein the first deployment space is created when a first vehicle seat longitudinal position of a vehicle seat allows the vehicle occupant to assume a usual vehicle seat longitudinal position, - a second airbag which, in the event of a collision, can be deployed into a second deployment space between the lower area of the instrument panel and the feet of the vehicle occupant, the second deployment space being created when a second vehicle seat longitudinal position of the vehicle seat, which is shifted rearward relative to the first vehicle seat longitudinal position, allows the vehicle occupant to assume a resting or comfortable position, and - an inflator for inflating the first or second airbag.

[0013] In this knee airbag arrangement according to the invention, the first and second airbags are triggered depending on the longitudinal position of the vehicle occupant in the passenger seat. This means that the first airbag, designed as a knee airbag, is triggered when the vehicle occupant is in a usual longitudinal position in the event of an impending vehicle collision, wherein the vehicle seat on which the vehicle occupant is sitting is displaced in the vehicle longitudinal direction into a first vehicle seat longitudinal position enabling such a usual longitudinal position. In such a first vehicle seat longitudinal position, the knee airbag is deployed into a first deployment space between a lower region of the vehicle's instrument panel and the vehicle occupant's knees. In this usual longitudinal position of the vehicle occupant, there is only a small distance between the lower region of the instrument panel and the vehicle occupant's knees.This first airbag couples the vehicle occupant to the vehicle's surroundings, i.e., to the instrument panel, as is usual for a knee airbag, to prevent the so-called "submarining" effect of the vehicle occupant. This means that in the event of a vehicle collision, the sinking of the vehicle occupant's upper body in the seated position due to movement of their lower leg in the direction of travel is prevented.

[0014] The second airbag, on the other hand, is triggered when the vehicle occupant is in a resting or comfortable position that corresponds to a second longitudinal position of the vehicle seat that is shifted rearward, i.e. against the direction of travel, compared to the first longitudinal position of the vehicle seat, which is suitable for a "normal" driving and sitting position of the vehicle occupant. In such a longitudinal position of the vehicle occupant, the distance between the lower area of the instrument panel and the knees of the vehicle occupant, as well as the space in front of the feet known as the second deployment space, is increased compared to a usual or "normal" longitudinal driving and sitting position of the vehicle occupant. In such a resting or comfortable position of the vehicle occupant, the second airbag deploys into this second deployment space, which is located between a lower area of the instrument panel and the feet of the vehicle occupant.This second airbag deploys in front of the vehicle occupant's feet, as seen in the direction of travel. When inflated, it cushions the movement of the occupant's feet so that they cannot pivot upward toward the lower part of the instrument panel. This provides adequate impact protection for the vehicle occupant's lower extremities, in particular, cushioning the foot against the vehicle's bulkhead.

[0015] With the knee airbag arrangement according to the invention, a vehicle occupant is protected as best as possible in the event of a vehicle collision, both in every longitudinal position of a vehicle seat and in every seating position of the vehicle occupant.

[0016] The inflation device of the knee airbag assembly according to the invention can be implemented in various ways. According to a first embodiment of the invention, the inflation device is designed as a gas generator with a propellant pack for generating propellant gas, a first igniter for igniting the propellant pack and inflating the first airbag, and a second igniter for igniting the propellant pack and inflating the second airbag.

[0017] A second development of the invention provides that the inflation device is designed with a propellant set for generating propellant gas and an igniter for igniting the propellant set. The gas generator has a first injection opening for introducing the propellant gas into the first airbag and a second injection opening for introducing the propellant gas into the second airbag, and the first and second injection openings are switchable. By switching the two injection openings, either the first airbag, the second airbag, or both airbags can be deployed simultaneously with different internal pressures.

[0018] According to a third embodiment of the invention, the inflation device is configured with a first gas generator with a propellant set and an igniter for generating propellant gas for the first airbag, and with a second gas generator with a propellant set and an igniter for generating propellant gas for the second airbag. This allows the two airbags to be activated independently of one another.

[0019] According to a further advantageous embodiment of the invention, the first airbag is designed with at least one airbag outlet and the second airbag with at least one airbag outlet, wherein the airbag outlets of the first and second airbags are switchable. Such airbag outlets serve to limit the internal gas bag pressure and soften the gas bag after the vehicle occupant is impacted. This allows the damping properties of the first and second airbags to be adapted to their function. The airbag outlets can thus be designed such that the first airbag has less damping than the second airbag.

[0020] Furthermore, it is advantageous to design the first airbag in such a way that it deploys into the first deployment space between the lower area of the instrument panel and the knees and an adjacent portion of the lower leg of the vehicle occupant. This means that not only the knee of the vehicle occupant but also a portion of the lower leg adjacent to the knee is supported by the first airbag.

[0021] According to a further advantageous embodiment of the invention, the second airbag is designed to deploy into the second deployment space between the lower area of the instrument panel and the feet and an adjacent portion of the lower leg of the vehicle occupant. Thus, not only the foot of the vehicle occupant but also a portion of the lower leg adjacent to the foot is supported by the second airbag.

[0022] Such a knee airbag arrangement according to the invention can be used both for the impact protection of a driver of a vehicle and a passenger of such a driver.

[0023] The second object is achieved by a method having the features of patent claim 8.

[0024] This method for triggering a knee airbag arrangement according to the invention is characterized by the following method steps: - Determining a vehicle seat longitudinal position of a vehicle seat occupied by a vehicle occupant by means of a vehicle seat sensor, - Determining a vehicle collision using a collision sensor, - Deployment of the knee airbag arrangement depending on the sensor signals of the vehicle seat sensor and the collision sensor, whereby - in the case of a first vehicle seat longitudinal position required for a normal passenger seat longitudinal position of the vehicle occupant, only the first airbag is triggered, and - in the event of a second vehicle seat longitudinal position being shifted rearward relative to the first vehicle seat longitudinal position required for a normal passenger seat longitudinal position of the vehicle occupant, the second airbag is triggered.

[0025] For this method according to the invention, it is necessary to determine the vehicle seat longitudinal position of the vehicle seat occupied by the vehicle occupant in the vehicle's longitudinal direction. If the vehicle occupant is in a usual vehicle seat longitudinal position with a short distance between the lower area of the instrument panel and the vehicle occupant's knees, the first airbag is deployed. If, on the other hand, the vehicle seat is moved backwards from the first vehicle seat longitudinal position corresponding to this usual vehicle seat longitudinal position of the vehicle occupant, i.e. against the direction of travel, into a second vehicle seat longitudinal position which corresponds to a resting or comfortable position for the vehicle occupant, the second airbag is deployed. In such a resting or comfortable position, the first airbag is deployed.When the vehicle occupant is in the comfortable position, the second airbag deploys in front of the vehicle occupant's feet, as viewed in the direction of travel. When inflated, it cushions the movement of the vehicle occupant's feet so that they cannot pivot upward toward the lower area of the instrument panel. This provides adequate impact protection for the vehicle occupant's lower extremities, particularly by cushioning the foot in the direction of the bulkhead or the underside of the footwell toward the dashboard and the vehicle's pedals.

[0026] By additionally determining the seating position of the vehicle occupant on the vehicle seat, the size of the first deployment space between the lower area of the instrument panel and the knees of the vehicle occupant or the size of the second deployment space between the lower area of the instrument panel and the feet of the vehicle occupant can be precisely determined.

[0027] The knee airbag arrangement according to the invention is suitable for use in all types of vehicles, in particular in motor vehicles, hybrid and electric vehicles.

[0028] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. In the drawings: Fig. 1 is a schematic representation of a vehicle with a vehicle occupant in a first seating position and a knee airbag arrangement according to the invention, Fig. 2 a schematic representation of the vehicle according to Fig. 1, in which the vehicle occupant is in a second seating position, Fig. 3 a schematic representation of an airbag module of the knee airbag arrangement according to the Fig. 1 and Fig. 2, Fig. 4 a schematic representation of an alternative airbag module of the knee airbag arrangement according to the Fig. 1 and Fig. 2, and Fig. 5 a schematic representation of another alternative airbag module of the knee airbag arrangement according to the Fig. 1 and Fig. 2.

[0029] The vehicle 10 according to the Fig. 1 and Fig. 2 is equipped with a knee airbag arrangement 1, which serves to protect a vehicle occupant 20 sitting on a vehicle seat 12 of the vehicle 10, who is in the Fig. 1 and Fig. 2 is shown as a driver in the driver's seat of the vehicle 10. The Fig. 1 and Fig. 2 each show the vehicle 10 in the state of a vehicle collision, in which the knee airbag assembly 1 is deployed. This knee airbag assembly 1 is part of an occupant protection system, which, in addition to the knee airbag assembly 1, has additional airbags, such as a driver airbag 13.

[0030] The knee airbag arrangement 1 consists of an airbag module 2, the structure of which in detail consists of Fig. 3. This airbag module 2 comprises, in an airbag module housing 2.1, a first airbag 3.1 and a second airbag 3.2, as well as an inflation device 4 for inflating these two airbags 3.1 and 3.2. The inflation device 4 consists of a gas generator 4.0 with a propellant set 4.1, a first igniter 4.2 with an injection opening 4.20, and a second igniter 4.3 with an injection opening 4.30. When the igniter 4.2 or 4.3 is ignited, the gas generated by the propellant set 4.1 is directed via the injection opening 4.20 or 4.30 into the corresponding first or second airbag 3.1 or 3.2.

[0031] In the event of an occurring or impending vehicle collision, the knee airbag assembly 1 is triggered by a sensor-controlled control unit 14, which receives the sensor signals from a vehicle seat sensor S1, a collision sensor S2, and an occupant position sensor S3. The first and second airbags 3.1 and 3.2 are triggered depending on the longitudinal seat position of the vehicle occupant 20.

[0032] The first airbag 3.1 is designed as a knee airbag and is triggered by the control unit 14 when the vehicle occupant 20 is in a usual longitudinal passenger seat position I according to Fig. 1, wherein the vehicle seat 12 on which the vehicle occupant 20 is sitting is in a first vehicle seat longitudinal position I', in which the vehicle occupant 20 can assume such a usual vehicle seat longitudinal position I. This first vehicle seat longitudinal position I' of the vehicle seat 12 enables the vehicle occupant 20, as driver, to assume the usual vehicle seat longitudinal position I for driving the vehicle 10.

[0033] In this first vehicle seat longitudinal position I' of the vehicle seat 12, the first airbag 3.1 is deployed as a knee airbag in a first deployment space R1 between a lower region 11.1 of the instrument panel 11 of the vehicle 10 and the knees 20.1 of the vehicle occupant 20, which are spaced slightly apart from the lower region 11.1 of the instrument panel 11, whereby the coupling of the vehicle occupant 20 to the vehicle environment, i.e. to the instrument panel 11, as is usual for a knee airbag, takes place. The first airbag 3.1 can be according to Fig. 1 additionally have the property that not only the knee area but also the parts of the lower leg 20.3 of the vehicle occupant 20 adjoining the knee 20.1 are supported.

[0034] The second airbag 3.2, on the other hand, is triggered by means of the control unit 14 when the vehicle occupant 20 is in a resting or comfort position as the occupant seat longitudinal position II, which corresponds to a second vehicle seat longitudinal position II' of the vehicle seat 12, which is shifted rearward in the vehicle longitudinal direction (x-direction), i.e. opposite to the direction of travel F, compared to the first vehicle seat longitudinal position I', which is suitable for a "normal" driving and sitting position as the occupant seat longitudinal position I of the vehicle occupant 20 (cf. Fig. 2), wherein the displacement from the first vehicle seat longitudinal position I' backwards into the second vehicle seat longitudinal position II' - and vice versa - is carried out by means of a seat longitudinal adjustment.

[0035] In this second vehicle seat longitudinal position II' of the vehicle seat 12, the second airbag 3.2 is deployed into a second deployment space R2 between the lower area 11.1 of the instrument panel 11 and the feet 20.2 of the vehicle occupant 20. This second airbag 3.2 therefore deploys in front of the feet 20.2 of the vehicle occupant 20, as viewed in the direction of travel F, and thus, when inflated, dampens the movement of the feet 20.2 of the vehicle occupant 20 in such a way that they cannot pivot upwards towards the lower area 11.1 of the instrument panel 11, thus avoiding a hard impact. The second airbag 3.2 can be Fig. 2 additionally have the property that not only the feet 20.2 but also the parts of the lower legs 20.3 adjoining the feet 20.2 are supported.

[0036] To detect the longitudinal position of the vehicle seat 12 and the seating position of the vehicle occupant 12, a vehicle seat sensor S1 and an occupant position sensor S3 are arranged in the vehicle 10 in addition to a collision sensor S2 for detecting a vehicle collision. The sensor data from these sensors S1, S2, and S3 are fed to the control unit 14 for evaluation, and if a corresponding evaluation result is available, the knee airbag arrangement 1 is triggered, along with any other airbags of the occupant protection system.

[0037] The two airbags 3.1 and 3.2 of the airbag module 2 each have at least one airbag outlet, the first airbag 3.1 having an airbag outlet 3.10, and the second airbag 3.2 having an airbag outlet 3.20. These airbag outlets 3.10 and 3.20 of the two airbags 3.1 and 3.2 are designed to be switchable.

[0038] The airbag outflows 3.10 and 3.20 serve to limit the internal gas bag pressure of the two airbags 3.1 and 3.2 and to limit the internal pressure in the event of a collision between the vehicle occupant 20 and the first or second airbag 3.1 or 3.2. This allows the damping properties of the first and second airbags 3.1 and 3.2 to be adapted to their respective functions. Thus, the airbag outflows 3.10 and 3.20 can be designed such that the first airbag 3.1 has lower damping than the second airbag 3.2.

[0039] One to the airbag module 2 according to Fig. 3 alternative structure show the airbag modules 2 after Fig. 4 and after Fig. 5.

[0040] The airbag module 2 according to Fig. 4 accommodates an inflation device 4 designed as a gas generator 4.0 in an airbag module housing 2.1. This gas generator 4.0 consists of a propellant set 4.1 for generating propellant gas and an igniter 4.4 for igniting the propellant set 4.1.

[0041] To supply the generated propellant gas to the two airbags 3.1 and 3.2, the gas generator 4.0 is designed with a first injection opening 4.41 for introducing the propellant gas into the first airbag 3.1 and a second injection opening 4.42 for introducing the propellant gas into the second airbag 3.2. These two injection openings 4.41 and 4.42 are switchable. The switchability of these two injection openings 4.41 and 4.42 is achieved by, for example, controlling the injection openings 4.41 and 4.42 via different input voltages. For example, depending on the applied voltage, one or the other injection opening would have to be switched using valves.

[0042] Thus, by means of the control unit 14, the two injection openings 4.41 and 4.42 can be controlled in such a way that, depending on the vehicle seat position of the vehicle seat 12, only the first airbag 3.1 or only the second airbag 3.2 is filled with propellant gas. In addition, it is also possible to control the degree of inflation of the two airbags 3.1 and 3.2. Furthermore, the two airbags 3.1 and 3.2 can be triggered simultaneously or with a time delay with a temporal overlap. Furthermore, it is also possible for this airbag module 2 according to Fig. 4 Airbag outflows shall be provided in the two airbags 3.1 and 3.2.

[0043] The airbag module 2 according to Fig. 5 comprises, in an airbag module housing 2.1, an inflation device 4 with a first gas generator 4.5 and a second gas generator 4.6. The first gas generator 4.5 consists of a propellant set 4.50, an associated igniter 4.51 and an injection opening 4.52. The second gas generator 4.6 is formed with a propellant set 4.60, an associated igniter 4.61 and an injection opening 4.62. Also in this airbag module 2 according to Fig. 5 the two airbags 3.1 and 3.2 can be provided with airbag outflows. REFERENCE SYMBOL: 1 knee airbag arrangement 2 airbag module 2.1 Airbag module housing 3.1 first airbag 3.10 Airbag outflow of the first airbag 3.1 3.2 second airbag 3.20 Airbag outflow of the second airbag 3.2 4 Inflation device 4.0 Gas generator 4.1 Propellant set 4.2 first igniter 4.20 Injection opening 4.3 second igniter 4.30 Inlet opening 4.4 Igniter 4.41 first injection opening 4.42 second injection opening 4.5 first gas generator 4.50 Propellant set of the first gas generator 4.5 4.51 Igniter of the propellant set 4.50 4.52 Injection opening 4.6 second gas generator 4.60 Propellant set of the second gas generator 4.6 4.61 Igniter of the propellant set 4.60 4.62 Injection opening 10 vehicles 11 Vehicle instrument panel 10 11.1 lower area of the instrument panel 11 12 Vehicle seat of the vehicle 10 13 Driver airbag 14 Control unit 20 vehicle occupants 20.1 Knee of the vehicle occupant 20 20.2 Feet of the vehicle occupant 20 20.3 Lower leg of the vehicle occupant 20 I usual longitudinal seat position of the vehicle occupant 20 I' first vehicle seat longitudinal position of the vehicle seat 12 II compared to the usual seating position I shifted longitudinal seat position of the vehicle occupant 20 II' second vehicle seat longitudinal position of the vehicle seat 12 R1 first deployment area of the first airbag 3.1 R2 second deployment area of the second airbag 3.2 S1 vehicle seat sensor S2 collision sensor S3 Occupant position sensor

Claims

[1] Knee airbag arrangement (1) for a vehicle (10) with an airbag module (2), wherein the airbag module (2) comprises: - a first airbag (3.1), which is designed as a knee airbag for a vehicle occupant (20) to be deployed in the event of a vehicle collision into a first deployment space (R1) between a lower region (11.1) of an instrument panel (11) and the knees (20.1) of the vehicle occupant (20), wherein the first deployment space (R1) is created when a first vehicle seat longitudinal position (I') of a vehicle seat (12) allows the vehicle occupant (20) to assume a usual vehicle seat longitudinal position (I), - a second airbag (3.2) which, in the event of a collision, can be deployed into a second deployment space (R2) between the lower region (11.1) of the instrument panel (11) and the feet (20.2) of the vehicle occupant (20), the second deployment space (R2) being created when a second vehicle seat longitudinal position (II') of the vehicle seat (12) is displaced rearwardly relative to the first vehicle seat longitudinal position (I') and allows the vehicle occupant (20) to assume a resting or comfortable position in the occupant seat (II), and - an inflation device (4) for inflating the first or second airbag (3.1, 3.2). [2] Knee airbag arrangement (1) according to claim 1, wherein the inflation device (4) is designed as a gas generator (4.0) with a propellant set (4.1) for generating propellant gas, a first igniter (4.2) for igniting the propellant set (4.1) and for inflating the first airbag (3.1) and with a second igniter (4.3) for igniting the propellant set (4.1) and for inflating the second airbag (3.2). [3] Knee airbag arrangement (1) according to claim 1, wherein the inflation device (4) is designed as a gas generator (4.0) with a propellant set (4.1) for generating propellant gas and an igniter (4.4) for igniting the propellant set (4.1), wherein - the gas generator (4.0) has a first injection opening (4.41) for introducing the propellant gas into the first airbag (3.1) and a second injection opening (4.42) for introducing the propellant gas into the second airbag (3.2), and - the first and second injection openings (4.41, 4.42) are switchable. [4] Knee airbag arrangement (1) according to claim 1, wherein the inflator (4) is designed with a first gas generator (4.5) with a propellant set (4.50) and an igniter (4.51) for generating propellant gas for the first airbag (3.1) and with a second gas generator (4.6) with a propellant set (4.60) and an igniter (4.61) for generating propellant gas for the second airbag (3.2). [5] Knee airbag arrangement (1) according to one of the preceding claims, in which the first airbag (3.1) is designed with at least one airbag outflow (3.10) and the second airbag (3.2) is designed with at least one airbag outflow (3.20), wherein the airbag outflows (3.10, 3.20) of the first and second airbags (3.1, 3.2) are switchable. [6] Knee airbag arrangement (1) according to one of the preceding claims, in which the first airbag (3.1) is designed to deploy into the first deployment space (R1) between the lower region (11.1) of the instrument panel (11) and the knees (20.1) and an adjoining part of the lower legs (20.3) of the vehicle occupant (20). [7] Knee airbag arrangement (1) according to one of the preceding claims, in which the second airbag (3.2) is designed to deploy into the second deployment space (R2) between the lower region (11.1) of the instrument panel (11) and the feet (20.2) and an adjoining part of the lower legs (20.3) of the vehicle occupant (20). [8] Method for triggering a knee airbag arrangement (1) according to one of the preceding claims, comprising the following method steps: - determining a vehicle seat position (I', II') of a vehicle seat (12) occupied by a vehicle occupant (20) by means of a vehicle seat sensor (S1), - Determining a vehicle collision by means of a collision sensor (S2), - triggering the knee airbag arrangement (1) depending on the sensor signals of the vehicle seat sensor (S1) and the collision sensor (S2), whereby - in the case of a first vehicle seat longitudinal position (I') required for a usual passenger seat longitudinal position (I) of the vehicle occupant (20), only the first airbag (3.1) is triggered, and - in the event of a second vehicle seat longitudinal position (II') being shifted rearward relative to the first vehicle seat longitudinal position (I') required for a normal passenger seat longitudinal position (I) of the vehicle occupant (20), the second airbag (3.2) is triggered. [9] Method according to claim 8, wherein, before the knee airbag arrangement (1) is triggered, a passenger seat longitudinal position (I, II) of the vehicle occupant (20) is determined by means of an occupant position sensor (S3). [10] Vehicle (10) with a knee airbag arrangement (1) according to one of claims 1 to 7.

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