Vehicle occupant restraint system and method for operating a vehicle occupant restraint system

Abstract

The invention describes a vehicle occupant restraint system (2) comprising a control unit and at least two restraint elements (8, 10) for the protection of lower extremities (6, 6′, 7, 7′) in the area of a footwell (4) of a vehicle of a vehicle occupant seated in a particular vehicle seat of the vehicle, wherein a first restraint element (8) is configured as a knee airbag module (12), wherein a second restraint element (10) is provided for mounting into the footwell (4) of the vehicle, especially in an area of the footwell (4) of the vehicle arranged in the vehicle longitudinal direction (x) ahead of the knee airbag module (12), wherein, in a situation of restraint, the control unit can differentiate between different given situations, wherein the given situation can be determined via a vehicle seat position and parameters relating to vehicle occupants, wherein, in the situation of restraint, when a situation is given in which the vehicle seat (5) is in a position shifted backwards, especially in a position shifted backwards compared to the standard position, and the vehicle occupant is a short and/or light person, the control unit only activates the foot airbag module (16) of the second restraint element (10).

Claims

1. A vehicle occupant restraint system comprising a control unit and at least two restraint elements for the protection of lower extremities in the area of a footwell of a vehicle of a vehicle occupant seated in a particular vehicle seat of the vehicle, wherein a first restraint element is in the form of a knee airbag module, wherein a second restraint element is provided for mounting into the footwell of the vehicle in an area of the footwell of the vehicle arranged in the vehicle longitudinal direction ahead of the knee airbag module, wherein the second restraint element comprises at least one foot airbag module including a foot airbag, wherein the control unit can differentiate, in a situation of restraint, between different given situations, the given situation being determinable via a vehicle seat position and parameters relating to vehicle occupants, wherein the control unit in the situation of restraint, when a situation is given in which the vehicle occupant is a short and/or light person and the vehicle seat is in a position shifted backwards, in a position shifted backwards compared to a standard position, only activates the foot airbag module of the second restraint element.

2. The vehicle occupant restraint system according to claim 1, wherein, in a situation in which the vehicle seat is in the standard position and/or the vehicle occupant is not a short and/or light person, in the situation of restraint at least the knee airbag module of the first restraint element is activated by the control unit, wherein the control unit can additionally activate, depending on the given situation, the second restraint element or a partial element of the second restraint element.

3. The vehicle occupant restraint system according to claim 1, wherein the second restraint element comprises a heel abutting point positioning module.

4. The vehicle occupant restraint system according claim 1, wherein the foot airbag of the foot airbag module comprises a low-pressure chamber or is configured as a low-pressure chamber.

5. The vehicle occupant restraint system according claim 1, wherein the knee airbag module comprises a knee airbag with at least one adaptive chamber.

6. The vehicle occupant restraint system according to claim 5, wherein the adaptive chamber of the knee airbag can be activated and/or controlled through the control unit.

7. The vehicle occupant restraint system according claim 1, wherein a knee airbag of the knee airbag module comprises a pressure-adaptive chamber.

8. The vehicle occupant restraint system according to claim 7, wherein the pressure-adaptive chamber of the knee airbag is in the form of a low-pressure chamber.

9. The vehicle occupant restraint system according claim 1, wherein a knee airbag of the knee airbag module comprises a depth-adaptive chamber.

10. The vehicle occupant restraint system according claim 3, wherein the heel abutting point positioning module comprises an airbag module.

11. The vehicle occupant restraint system according claim 3, wherein the heel abutting point positioning module comprises a deformation element.

12. The vehicle occupant restraint system according to claim 11, wherein the deformation element comprises a bistable spring element.

13. The vehicle occupant restraint system according to claim 11, wherein the deformation element comprises a foamable element.

14. The vehicle occupant restraint system according claim 1, comprising at least one sensor element for detecting the given situation.

15. The vehicle occupant restraint system according to claim 14, wherein the sensor element comprises a camera system and/or sensors disposed and/or integrated in vehicle seat elements and/or in the footwell.

16. A method for operating a vehicle occupant restraint system according claim 1, said method comprising the following steps of: detecting and determining a position of the vehicle seat and/or parameters relating to vehicle occupants in a situation of restraint; determining the given situation by the control unit; activating the restraint elements and/or partial elements of the restraint elements required for the restraint in the given situation.

17. The method for operating a vehicle occupant restraint system according to claim 16, wherein, when detecting the parameters relating to vehicle occupants, a body weight and/or a body height and/or a position of the vehicle occupant in the vehicle seat is/are determined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features and details of the invention will be evident from the following description of an example embodiment that is understood to be not limiting as well as by way of the drawings, wherein:

(2) FIG. 1 shows a schematic view of the footwell of a vehicle with an embodiment of a vehicle occupant restraint system according to the invention and lower extremities of a 50%-person in a standard position;

(3) FIG. 2 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 1 in an activated state;

(4) FIG. 3 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 1 with lower extremities of a 5%-person in a standard position;

(5) FIG. 4 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 3 in an activated state;

(6) FIG. 5 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 1 with lower extremities of a 50%-person in a comfort position;

(7) FIG. 6 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 5 in an activated state at a time t1 at which feet of the 50%-person impact on a heel abutting point positioning module;

(8) FIG. 7 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 5 in an activated state at a time t2 at which knees of the 50%-person impact on a knee airbag;

(9) FIG. 8 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 5 in an activated state at a time t2 at which knees of the 50%-person impact on an alternative embodiment of the knee airbag;

(10) FIG. 9 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 1 with lower extremities of a 5%-person in a comfort position;

(11) FIG. 10 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 9 in an activated state at a time t1 at which feet of the 5%-person impact on a low-pressure chamber of the knee airbag;

(12) FIG. 11 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 9 in an activated state at a time t2, after feet of the 5%-person have impacted on the low-pressure chamber of the knee airbag;

(13) FIG. 12 shows a schematic view of an alternative embodiment of a heel abutting point positioning module in a) a non-activated state and b) an activated state;

(14) FIG. 13 shows a schematic view of another alternative embodiment of a heel abutting point positioning module in a) a non-activated state and b) an activated state;

(15) FIG. 14 shows a schematic view of the footwell of a vehicle with a second embodiment of a vehicle occupant restraint system according to the invention and lower extremities of a 5%-person in a comfort position in an activated state of the vehicle occupant restraint system at a time t1 immediately before feet of the 5%-person will impact on a foot airbag;

(16) FIG. 15 shows a schematic view of the footwell with the vehicle occupant restraint system according to FIG. 14 at a time t2 after the feet of the 5%-person have impacted on the foot airbag;

(17) FIG. 16 shows a schematic view of the footwell with the vehicle occupant restraint system according to the invention of FIG. 14 with an alternative activation of the restraint elements by the control unit at a time t1 immediately before feet of the 5%-person will impact on a foot airbag; and

(18) FIG. 17 shows a schematic view of the footwell with the vehicle occupant restraint system of FIG. 16 at a time t2 after the feet of the 5%-person have impacted on the foot airbag.

DESCRIPTION

(19) FIG. 1 schematically illustrates a footwell 4 of a vehicle including a vehicle occupant protection restraint system 2. The vehicle occupant restraint system 2 is shown in FIG. 1 in a non-activated state. The vehicle occupant protection restraint system 2 is configured for protecting the lower extremities 6 of a vehicle occupant. The lower extremities comprise, inter alia, the thigh 62, the knee 70, the lower leg with the shin (tibia) 64 as well as the foot 66 with the heel 68. The lower extremities 6 correspond, as to their dimensions, to the lower extremities 6 of a 50%-person. The lower extremities 6 are shown in a position in which the vehicle seat 5 is in a standard position. In FIG. 1, merely part of the seating area of the vehicle seat 5 is shown. The further Figures do without a representation of the vehicle seat 5 for reasons of clarity.

(20) The vehicle occupant protection restraint system 2 has a first restraint element 8 that is in the form of a knee airbag module 12. The knee airbag module is arranged in a lower area of the instrument panel 3 in the vehicle vertical direction y. The vehicle occupant protection restraint system 2 further comprises a second restraint element 10. The second restraint element 10 is configured as a heel abutting point positioning module 14. The heel abutting point positioning module 14 is disposed in a transition area 39 between a vehicle floor 40 and a front wall 38 delimiting the footwell 4. The heel abutting point positioning module 14 is disposed beneath a vehicle floor lining 42. The vehicle floor lining 42 may be, for example, a vehicle carpet mounted in the footwell 4.

(21) FIG. 2 illustrates the vehicle occupant restraint system 2 in an activated state in a situation of restraint in which a 50%-person is seated in the vehicle seat in a standard position. In the shown embodiment, only the knee airbag module 12 of the first restraint element 8 is activated by the control unit 100 of the vehicle occupant restraint system 2. The knee airbag 20 of the knee airbag module 12 in the shown embodiment comprises plural chambers 22, 24, 26 which are separated, for example, by tethers 28 and 30. After activation of the knee airbag module 12, the knee airbag 20 is filled with gas by a gas generator 11. The lowest chamber 22 in the vehicle longitudinal direction x of the knee airbag 20 is configured as a pressure-adaptive low-pressure chamber 22. The low-pressure chamber 22 has a lower internal pressure than the two chambers 24 and 26 at the illustrated point in time at which the knee 70 and the shin 64 impact on the knee airbag 20. A forward movement 72 of the lower extremities 6 is limited, on the one hand, by the heel abutting point 18. The heel abutting point 18 is arranged in the transition area 39 between the vehicle floor 40 and the front wall 38 delimiting the footwell 4 and limits the forward movement of the foot 66. On the other hand, the forward movement 72 of the lower extremities 6 is limited by the knee airbag 20.

(22) FIG. 3 illustrates the footwell 4 with the lower extremities 7 of a 5%-person who is seated in a vehicle seat in the standard position. Further, in dotted lines the lower extremities 6 of a 50%-person are shown. It is evident from the comparison of the lower extremities 7 of the 5%-person and the lower extremities 6 that especially the foot 66 of a 5%-person is further behind in the travel direction x. Consequently, a space between the heel 68 of the 5%-person and the heel abutting point 18 is significantly increased as compared to the space with the 50%-person.

(23) As is shown in FIG. 4, in a situation of restraint, apart from the knee airbag module 12 of the first restraint element 8, also the heel abutting point positioning module 14 is activated. In the shown embodiment, the heel abutting point positioning module 14 comprises an airbag module 34 including a gas generator 33 and an airbag 36. By filling the airbag 36 the vehicle floor lining 42 is shifted to the position marked with 42′. In addition, the heel abutting point 18 is thus shifted backwards in the vehicle longitudinal direction x toward the foot 66 of the 5%-person to the position marked with 18′.

(24) The vehicle occupant restraint system may include a control unit 100 for controlling and activating the first and/or second restraint element(s). The control unit 100 of the vehicle occupant restraint system may be integrated in a vehicle control system, especially in an airbag control system. In particular, the control unit 100 may be integrated in a vehicle control system by which further restraint systems can be additionally activated and controlled.

(25) For determining the parameters relating to vehicle occupants and/or the relative position of the vehicle seat, the vehicle occupant restraint system can comprise at least one sensor element 102. Alternatively, or additionally, the control unit 100 can access the sensor data of one or more sensor elements 102 integrated in the vehicle. The sensor element 102 may comprise a camera system, for example. Furthermore, the sensor element 102 can include, e.g., one or more sensors integrated in vehicle seat elements. In addition, the control unit 100 can preferably make also use of and/or access sensor data of further sensor elements arranged in the vehicle, especially in the footwell, for detecting the given situation.

(26) By displacing the heel abutting point 18 to the position marked with 18′, the forward movement of the foot 66 is limited at an early stage in the situation of restraint, which allows to optimize especially the immersion of the knee 70 and the shin 64 into the knee airbag of the 5%-person. In addition, the shift of the heel abutting point 18 to the position marked with 18′ prevents the foot 66 and the shin 64 from swinging upwards.

(27) In FIG. 5, the lower extremities 6′ of a 50%-person are shown who is seated in a vehicle seat 5′ in a comfort position in which the vehicle seat 5′ is shifted backwards compared to the standard position (vehicle seat 5—shown by a dotted line). As compared to the arrangement of the lower extremities 6 in the standard position (shown by a dotted line), the lower extremities 6′ are arranged further behind in the comfort position.

(28) FIG. 6 illustrates a situation of restraint for the lower extremities 6′ of the 50%-person in the comfort position. FIG. 6 shows that, apart from the knee airbag module 12 of the first restraint element 8, also the airbag module 34 of the heel abutting point positioning module 14 of the second restraint element 10 was activated by the control unit 100. FIG. 6 illustrates the vehicle occupant restraint system 2 at a time t1 when the foot 66 impacts with the heel 68 on the heel abutting point 18′ shifted backwards. Thus, the forward movement of the foot 66 is limited and, for example, the foot 66 and the shin 64 are prevented from swinging upwards.

(29) FIG. 7 illustrates the situation of restraint at a subsequent time t2 when the knee 70 and the shin 64 impact on the filled knee airbag 20. The protective effect of the knee airbag 12 for the lower extremities can be improved by limiting the forward movement of the foot 66 by the heel abutting point positioning module 14.

(30) FIG. 8 illustrates the vehicle occupant restraint system 2 equally at the time t2. The vehicle occupant restraint system 2 of FIG. 8 differs from the vehicle occupant restraint system 2 of FIG. 7 merely by the embodiment of the knee airbag module 12. In the knee airbag module 12 of FIG. 8, the knee airbag 20′ includes a depth-adaptive chamber 32. The depth-adaptive chamber 32 is formed, in the shown example embodiment, by the tether 30′ being released on one side in the area of the knee airbag module 12 by a release unit. In this way, in the area of the two upper chambers 24 and 26 the knee airbag 20′ can expand further toward the lower extremities 6′ of the vehicle occupant. The release unit for releasing the tether 30′ is activated by the control unit 100.

(31) In FIG. 9, the lower extremities 7′ of a 5%-person seated in a vehicle seat 5′ in a comfort position are shown. In comparison with the arrangement of the lower extremities 6 of the 50%-person (shown by a dotted line) and lower extremities 7 of the 5%-person (shown by a dash-dot line) in the vehicle seat 5 in the standard position (shown by a dotted line), the lower extremities 7′ are arranged still further behind in the comfort position.

(32) In FIG. 10 a situation of restraint for the lower extremities 7′ of the 5%-person in the comfort position is illustrated. FIG. 10 shows the vehicle occupant restraint system 2 at a time t1 when the foot 66 impacts on the lowest chamber 22 of the knee airbag 20. The chamber 22 is configured as a low-pressure chamber 22 which, in a filled state or at least when the feet 66 impact on the knee airbag 20, has a lower internal pressure than the two further chambers 24 and 26 of the knee airbag.

(33) In the illustrated embodiment, only the knee airbag module 12 of the first restraint element 8 is activated by the control unit 100. The heel abutting point positioning module 14 is not activated in the shown vehicle occupant restraint system 2. In the illustrated embodiment, the activation does not take place especially because it was determined by the control unit 100 that the heel abutting point 18′ shifted backwards could not prevent the foot 66 and the shin 64 from swinging upwards.

(34) FIG. 11 shows the restraint situation of FIG. 10 at a later point in time t2 when the feet 66 of the vehicle occupant have already impacted on the low-pressure chamber 22. The lower internal pressure of the low-pressure chamber 22 enable the feet 66 to “immerse” into the low-pressure chamber 22. Thus, rebounding of the feet 66 and the shins 64 can be prevented or at least weakened.

(35) FIGS. 12 and 13 illustrate alternative embodiments of the heel abutting point positioning module 14′ and 14″. For the heel abutting point positioning modules 14′ and 14″ the shift of the heel abutting point 18 to the position marked with 18′ is carried out via a deformation element.

(36) In the heel abutting point positioning module 14′ shown in FIG. 12 a) and b), the deformation element is configured as a bistable spring element 44. The bistable spring element is disposed beneath the vehicle floor lining 42 in the transition area 39 between the front wall 38 delimiting the footwell 4 and the vehicle floor 40.

(37) The bistable spring element 44 can be excited by an actuator 48 to change its shape from the first stable position shown in FIG. 12 a) to a second stable position shown in FIG. 12 b).

(38) In the heel abutting point positioning module 14″ shown in FIG. 13 a) and b), the deformation element is represented as a foamable element 46. The foamable element 46 comprises a material 47 which can be foamed by excitation and thus increases its volume. The foamable element 46 is disposed beneath the vehicle floor lining 42 in the transition area 39 between the front wall 38 delimiting the footwell 4 and the vehicle floor 40.

(39) Upon activation of the heel abutting point positioning module 14″, the foaming process is started by the control unit 100 by an appropriate actuator 48′. The vehicle floor lining 42 is lifted by the foamed material 47′ into the position marked with 42′. The heel abutting point 18 is shifted by the foamed material toward the vehicle occupant to the position marked with 18′. The vehicle floor lining 42 can be fixed at the shifted heel abutting point 18′ on the vehicle floor 40 so as to obtain a defined shift of the heel abutting point 18 to the position marked with 18′.

(40) FIGS. 14 and 15 illustrate another embodiment of the vehicle occupant restraint system 2 with the lower extremities 7′ of a 5%-person in a vehicle seat 5′ in a comfort position in which the vehicle seat 5′ is shifted backwards. For the purpose of comparison, in FIG. 14 the vehicle seat 5 is additionally shown in dotted line in the standard position. The vehicle occupant restraint system 2 differs from the vehicle occupant protection system 2 of FIGS. 1 to 11 in that the knee airbag 21 of the knee airbag module 12 includes no low-pressure chamber. Moreover, the second restraint element 10 comprises a foot airbag module 16 in addition to the heel abutting point positioning module 14.

(41) In the shown example embodiment, the control unit 100 has activated the knee airbag module 12 of the first restraint element 8 as well as the foot airbag module 16 of the second restraint element 10 for the given situation. FIG. 14 illustrates the situation of restraint at a time t1 immediately before the foot 66 impacts on a foot airbag 50. Further, FIG. 15 illustrates the situation of restraint at a time t2 after the foot 66 has impacted on and “immersed” into the foot airbag 50. In the further points, the shown situation of restraint corresponds to the situation of restraint shown in FIGS. 10 and 11.

(42) The foot airbag 50 of the foot airbag module 16 is configured as a low-pressure chamber 52. The low-pressure chamber 52 in the filled state has a lower internal pressure than the chambers 25 and 27 of the knee airbag 21 of the knee airbag module 12 of the first restraint element 8.

(43) In the installed state, the foot airbag module 16 is disposed in the lower area of the instrument panel 3 ahead of the knee airbag module 12 (relating to the vehicle vertical direction y and the vehicle longitudinal direction x).

(44) In the shown example embodiment of FIGS. 14 and 15, the low-pressure chamber 52 of the foot airbag 50 substantially adopts the function of the pressure-adaptive low-pressure chamber 22 of the knee airbag 20 of the example embodiment shown in FIGS. 1 to 11.

(45) In particular, also the low-pressure chamber 52 enables the feet 66, due to the lower internal pressure, to “immerse” into the low-pressure chamber 52. Thus, in this case rebounding of the feet 66 and of the shins 64 can equally be prevented or at least weakened.

(46) The foot airbag module 16 in such embodiment of the vehicle occupant restraint system 2 is only activated, for example, if a 5%-person is seated in the vehicle seat in the comfort position.

(47) FIGS. 16 and 17 illustrate a vehicle occupant restraint system 2 with the lower extremities 7′ of a 5%-person in a vehicle seat 5′ in a comfort position which, as to its structure, corresponds to the vehicle occupant restraint system 2 of the FIGS. 14 and 15. In the comfort position, the vehicle seat 5′ is shifted backwards as compared to the vehicle seat 5 in the standard position (shown in dotted line).

(48) The vehicle occupant restraint system 2 of FIGS. 16 and 17 differs from the vehicle occupant restraint system 2 of FIGS. 14 and 15 by an alternative activation of the restraint elements in a situation of restraint, when a particular situation is given.

(49) The particular situation is given if it is detected by the control unit 100 that the vehicle seat 5 is in a position shifted backwards, especially in a comfort position, and the vehicle occupant is a short and/or light person, especially a 5%-person.

(50) When said particular situation is given, only the foot airbag module 16 of the second restraint element 10 is activated by the control unit 100. In the further possible situations in which the vehicle seat is in a standard position and/or in the vehicle seat a person is seated who is taller and/or heavier than a 5%-person, at least the knee airbag module 12 of the first restraint element 8 is activated by the control unit 100. Depending on the situation, moreover the foot airbag module 16 and/or the heel abutting point positioning module 14 of the second restraint element 10 can be activated by the control unit 100.