WO1999012777A1

WO1999012777A1 - Method and device for controlling an air-bag system in a motor vehicle

Info

Publication number: WO1999012777A1
Application number: PCT/DE1998/002340
Authority: WO
Inventors: Walter Baumgartner
Original assignee: Siemens Aktiengesellschaft
Priority date: 1997-09-11
Filing date: 1998-08-13
Publication date: 1999-03-18
Also published as: DE19740020A1

Abstract

The invention relates to a device for controlling an air-bag system in a motor vehicle, comprising a control circuit (3) which in accordance with data (a) of an impact detection device (1) triggers the inflation of an air-bag (422, 432) which can be filled to different volume levels (4221, 4222, 4223). The volume (4221, 4222, 4223) is adjusted after inflation of the air-bag (422, 432) has been triggered in accordance with current data (a) of the impact detection device (1) and/or current data (x) of a device for detecting passengers or objects (2).

Description

description

DEVICE AND METHOD FOR CONTROLLING A GAS BAG ARRANGEMENT IN A MOTOR VEHICLE

The invention relates to a device and a method for controlling an airbag arrangement in a motor vehicle.

A known device for controlling an airbag arrangement in a motor vehicle (DE 195 29 794 AI) has an impact detection device and a control circuit which, depending on data from the impact detection device, initiates the inflation of an airbag which can be filled to different volume levels or with different inflation speeds. By determining the occupant weight or the occupant sitting position, a filling volume or an inflation speed is calculated before the gas bag is actually initiated. With the filling volume determined in this way or the inflation speed determined in this way, the gas bag is inflated when the impact detection device has recognized a sufficiently strong negative vehicle acceleration.

Such a device adapts the filling quantity of the gas bag to the occupant position determined when the filling process is initiated. However, since filling the gas bag with a gas mixture or air takes a period of several milliseconds and the occupant shifts during this period due to the impact, in particular in the direction of the deploying airbag, the airbag does not offer protection adapted to the occupant position guaranteed. The airbag can injure the occupant due to an excessive filling volume or an excessive impact speed.

The object of the invention is therefore to provide a control system for an airbag arrangement in a motor vehicle which avoids the disadvantages of the known control system and which, in particular, ensures the best possible and, in particular, low-pulse catching effect of the airbag for the occupants.

The part of the object of the invention relating to the device is solved by the features of claim 1. The part of the object of the invention relating to the method is solved by the features of claim 5.

The control circuit adjusts the airbag volume to be reached or the inflation speed after the airbag has been inflated. The change in the filling volume or the inflation speed caused by the adjustment depends in particular on current data from the impact detection device and / or from current data from a device for occupant or object detection. These current data reflect in particular the impact situation or the occupant or object position after the gas bag has been inflated.

By means of the device according to the invention or the method according to the invention, the catching effect of the gas bag can be adapted extremely precisely to the current impact situation or occupant position, so that the momentum balance of the inflating airbag and displacing occupant is as low as possible is. In this way, the occupant is effectively protected by the gas bag without being injured by the inflation of the gas bag. The device according to the invention and the method according to the invention allow continuous changes or changes in discrete stages of the filling volume already achieved or intended to be achieved or the inflation speed or the inflation pressure.

Advantageous developments of the invention are characterized by the subclaims.

Embodiments of the invention and its advantageous developments are explained in more detail in the drawing. Show it:

FIG. 1 shows a block diagram of the device according to the invention,

FIG. 2 shows a flow chart for the method according to the invention, and

FIG. 3 shows the course of the filling volume of a gas bag changing over time, controlled by the method steps according to the invention.

FIG. 1 shows a device according to the invention for controlling an airbag arrangement 4 in a motor vehicle with an impact detection device 1, an occupant detection device 2 and a control circuit 3.

The impact detection device 1 supplies data d _a to the control circuit 3, preferably in the form of signals. The Impact detection device 1 preferably contains one

Acceleration sensor for detecting a deceleration of the motor vehicle caused by an impact and / or a proximity sensor, e.g. B. an ultrasonic sensor for detecting the approach of an obstacle to the motor vehicle and / or an impact sensor, for. B. in the form of a force or pressure sensor to detect the intrusion of an obstacle in the motor vehicle. The sensitivity axis of these sensors is oriented in the direction from which an impact is to be detected, that is to say, for example, parallel to the longitudinal axis of the vehicle for detecting a front, rear or oblique impact or transversely to the longitudinal axis of the vehicle for detecting a side impact. The individual sensors can be outsourced, that is to say arranged on the edge of the vehicle and thus close to the potential impact location, or else together with the control circuit 3 in a central position in the vehicle - for example on the vehicle tunnel - in a common control unit. The data d _a supplied to the control circuit 3 can represent continuous analog signals or already discretized digital data. In any case, the control circuit 3 can distinguish at least with the aid of the data d _{a provided} by the impact detection device 1 whether there is a sufficiently strong impact to trigger one or more occupant protection devices.

The occupant recognition device 2 can preferably distinguish one vehicle seat occupied by an occupant, one occupied by an object and one unoccupied. Furthermore, the occupant recognition device can preferably determine the occupant position, but at least classify it. Accordingly, the occupant recognition device 2 data d _x to the control circuit 3. The occupant detection device 2 can use a number of different sensor principles: for example a weight detection or a query of the belt buckle status to distinguish between an occupied or an unoccupied vehicle seat. to

Occupant position detection can e.g. B. capacitive, infrared - ultrasonic or other sensors can be used.

The control circuit 3 is preferably designed as a microprocessor which receives the data d _a and d _x , possibly converts and evaluates it. The control circuit 3 is connected via lines to gas bag arrangements 41, 42 and 43. Each gas bag arrangement 41, 42, 43 contains one or more gas generators 411, 4211, 4212, 4213, 4311, 4312, 4313, and associated gas bags 412, 422, 433 with one or more chambers 412, 4221, 4222, 4223, 432. General is assigned to each gas generator 411, 4211, 4212, 4213, 4311, 4312, 4313 an ignition element (not shown) which is ignited by the application of a high-energy current pulse Z ₀ to Z ₆ , the gas generator being released during the ignition to release gas by the energy released during ignition - e.g. B. for burning tablets with the release of gas - caused.

The first gas bag arrangement 41 has a conventional gas bag 412 with only one chamber. For inflation, the gas generator 411 receives the ignition signal Z ₀ from the control circuit 3. The second gas bag arrangement 42 has three gas generators 4211, 4212, 4213, each of which is assigned a chamber 4221, 4222, 4223 of the gas bag 422. Each gas generator 4211, 4212, 4213 can be ignited by its own, individual ignition signal Z _lr Z ₂ , Z ₃ . The control circuit 3 decides when about selection, order and time offset between the

Ignition of individual chambers 4221, 4222, 4223. The third gas bag arrangement 43 contains three gas generators 4311, 4312, 4313, the gas of which, when ignited, flows into a common gas bag 432 with only a single chamber.

If the control circuit 3 recognizes on the basis of the data d _{a from} the impact detection device 1 that there is a front impact, it initiates, for example, the inflation of the first chamber / volume stage 4221 of the gas bag arrangement 42 by actuating the gas generator 4211 with the ignition signal Z _x . At the same time, the control circuit 3 generates an ignition pulse Z ₄ for the gas generator 4311 of the third gas bag arrangement. If, in the second gas bag arrangement 42, each gas generator 4211, 4212, 4213 is designed such that it provides gas for completely filling the chamber 4221, 4222, 4223 assigned to it, each gas generator 4311, 4312, 4313 of the third gas bag arrangement 43 is designed such that he can fill the entire chamber 432 with gas. After the above-described ignition signals Z and Z ₄ have been generated, data d _a and data d _{x from} the impact detection device 1 and the occupant detection device 2 are recorded and processed by the control circuit 3, so that even after the inflation has been initiated, at least a first gas bag chamber / volume stage Impact situation and / or the occupant position and in particular changes in the impact situation or the occupant position can be recognized and evaluated by the control unit 3. If a change in the crash situation or the occupant position compared to the time at which, for example, the ignition signals Z _λ and Z ₄ were emitted, is significant and in particular exceeds a threshold value, is indicated by the control circuit 3 reacts to the changed impact situation or the changed occupant position.

If the control circuit 3 detects, for example, during the impact that the impact intensity is greater than originally assumed and the occupant is at the same time in a sitting position which allows the associated gas bag to be inflated to a greater extent, then in a further step by generating the ignition signals Z ₂ for the gas generator 4212 and Z ₃ for the gas generator 4213 and the ignition signals Z ₅ and Z ₆ for the gas generators 4312 and 4313, the gas bags 422 and 432 are inflated to a larger volume level or faster than previously to the intended volume level.

FIG. 3 shows the filling volume of a gas bag over time in three figures. 3a is based on the gas bag arrangement 42 from FIG. 1. At the time t _x , the control circuit 3 detects a slight impact, which requires the gas bag 422 to be inflated at least to its volume V _{1 #,} ie, the gas generator 4211 to inflate at least the first chamber 4221. At time t ₂ , the first chamber 4221 is filled to volume V _x with gas. At time t ₃ , control circuit ₃ recognizes that the impact is stronger than assumed at time t _x , so that a larger gas bag volume is required for effective protection. Because of this, the ignition signal Z ₂ for the gas generator 4212 is generated by the control circuit 3 at the time t ₃ . At time t _4, the second chamber 4222 is completely filled to its volume V _2, so that the entire volume content V _tot of the gas bag 422 is additively composed of the volume V, and V ₂ of the

Chambers 4221 and 4222 composed and the vehicle occupants provides the best possible health-friendly protection for the present impact on the vehicle seat.

The same filling profile of an airbag according to FIG. 3a) under the same conditions with regard to impact detection and impact assessment is achieved if instead of the airbag arrangement 42 the airbag arrangement 43 according to FIG. 1 is used, each gas generator 4311, 4312, 4313 releasing the chamber 432 with only one gas Partial volume V _1; V ₂ , V ₃ can fill. For example, gas generator 4311 only supplies gas for volume V _x according to FIG. 3a, gas generator 4312 only supplies gas volume V ₂ according to FIG. 3a. By sending the ignition signals Z ₄ at time t _x and Z ₅ at time t ₃ , this gas bag arrangement 43 is also distinguished by the same volume filling profile V _tot (t) as the gas bag arrangement 42 described above.

In the case of the volume filling curve V _tot according to FIG. 3a), it is assumed that a change in the volume filling stage V _{x is} only considered necessary at a point in time t ₃ at which at least the first volume filling stage V _{x has} already been fully reached. Of course, according to FIG. 3c, the original decision to inflate only one stage of a multi-stage gas bag can also be revised at a time when the inflation process of this first chamber has not yet been completed. According to FIG. 3c, the ignition signal Z for the gas bag arrangement 42 is again generated at the time t. The first chamber 4212 is then continuously filled with gas and would be completely filled to volume V- at time T ₃ . At a time t ₂ , at which the first chamber 4221 is not yet fully inflated, it is now recognized that the occupant remains in a relatively far-back position that requires inflation of the gas bag 422 to a larger volume. At time t ₂ is therefore generates the ignition signal Z _2, so that it is started during the full stuffing of the first chamber 4221 with the stuffing of the second chamber 4222 - see the upper branch of the graph in Figure 3c). At time t ₄ , both chambers 4221, 4222 are completely filled to the total volume V _tot = V + V ₂ . Igniting a gas generator at a point in time at which another gas generator has already been ignited - however, this has not yet released all of its gas - not only causes the gas bag to inflate to a new level, but also increases the inflation speed in relation to the total volume to be inflated. Ignition of a gas generator after another already ignited

The gas generator has released all of its gas corresponds to a slowdown in the inflation speed in relation to the total volume to be inflated. It is irrelevant whether the gas from the generators flows into a common chamber or into separate chambers of the gas bag.

The gas generators are actuators for the controlled inflation of a gas bag to different volume levels or with different inflation speeds. However, a valve arranged between the gas generator and the gas bag can be used as the actuator, which continuously controls the amount of gas flowing into the gas bag or the chamber. A valve can also be used as an actuator, which in its open state allows air or gas to flow out of the gas bag or from the chamber. The lower branch of the drawn in Figure 3c Graphene indicates the filling process for an airbag with such a / drain valve. At time t ₂ , the control circuit 3 recognized that the occupant had already advanced to a large extent in the direction of the unfolding gas bag and that further inflation was therefore a danger. Therefore, at time t _2, a valve arranged between chamber 4221 and the surroundings is opened by control circuit 3, so that chamber 4221 is not inflated to its intended maximum filling quantity V- _L but only to a small volume V ₀ . By opening said valve, gas entering the chamber 4221 from the gas generator 4211 between the time t ₂ and the time t ₃ flows through the valve out of the chamber 4221 to the same extent. At the time t ₃ , the valve is closed again, so that the total filling volume V _tot remains constant V ₀ .

FIG. 3b describes the filling of the gas bag arrangement 43 in accordance with FIG. 1, with each gas generator 4311, 4312, 4313 storing a sufficient amount of gas in order to completely fill the single chamber 432 to the volume V. Here, too, a valve is arranged between chamber 432 and the surroundings, so that gas can be released from the chamber 432 to the surroundings in a controlled manner, as a result of which the filling quantity of the chamber 432 is made variable. At time t ₂ , when the maximum filling volume V has not yet been reached, the valve is opened slightly so that the entire inflowing gas quantity does not flow out via the valve.

FIG. 2 shows a flow chart for the method according to the invention. After the start of the method with step S1, data d _{a of} the impact detection device 1 in are stored in step S2 the control circuit 3 is read in and evaluated in step S3. If it is recognized in step S4 that there is a sufficiently severe impact to ignite at least one stage of the gas bag, the process continues with step S5 in that at least this first stage of the gas bag is triggered by an associated ignition signal. If no such severe impact is detected, new data d _{a of} the impact detection device 1 are read in with step S2. Even after the inflation of the first stage of the gas bag has been initiated in step S5, in particular data d _{x of} an occupant detection device 2 are read into the control circuit 3 in step S6 and evaluated in step S7. If it is determined in step S8 that, based on this current data d _x, the occupant position has changed significantly compared to an occupant position at a previous point in time - for example with step S2 - then in step S10 the inflation speed or the filling volume to be achieved of the associated gas bag arrangement is determined Generation of further control signals corrected or changed. If it is not necessary to change the triggering decision made in step S4, data d _{x of} the occupant detection device 2 in particular are also read in with step S6 and checked in step S7.

Depending on the possible variations with regard to filling levels and inflation speeds, the occupant position or the impact situation can continue to be observed even after step S10 and further corrections can be initiated by further actuating signals if necessary. However, is the potential for change possibilities exhausted or has the impact advanced so far in time that changes in the inflation speed or in the filling volume are insignificant for the occupant are protection, so in step Sll the invention

Procedure ended.

Numerous / modifications of the invention are possible: in particular, not only the data of the impact detection device but also the data of the occupant detection device, in particular with regard to the occupant position, can be used to initiate the inflation of the gas bag.

Claims

claims

1. Device for controlling an airbag arrangement in a motor vehicle, - with an impact detection device (1),

with a control circuit (3) which, depending on data (a) from the impact detection device (1), initiates the inflation of an airbag (422, 432) which can be filled to different volume levels (4221, 4222, 4223) or with different inflation speeds or inflation pressures,

- in which the control circuit (3) adjusts the volume (4221, 4222, 4223) or the inflation speed or the inflation pressure after the inflation of the gas bag (422, 432) has been initiated, depending on current data (a) of the impact detection device (1) and / or of current data (x) of a device for occupant or object detection (2).

2. Device according to one of the preceding claims, in which the current data (a, x) represent an impact situation and / or an occupant or object position after the inflation of the gas bag (422, 423) has been initiated.

3. Device according to one of the preceding claims, wherein the impact detection device (1) at least one acceleration sensor for detecting the distortion of the motor vehicle and / or a proximity sensor for detecting the approach of an obstacle to the motor vehicle and / or an impact sensor for detecting the intrusion of an obstacle - Has nisses in the motor vehicle.

4. Device according to one of the preceding claims, wherein the device for occupant and / or object detection

(2) has at least one sensor for monitoring the belt buckle and / or a sensor for weight detection and / or a sensor for occupant position detection and / or a sensor for object differentiation.

5. Method for controlling an airbag arrangement in a motor vehicle, in which the inflation of an airbag (422, 422, 42223) that can be filled to different volume levels (422, 422, 423) or with different inflation speeds is initiated as a function of data (a) of an impact detection device (1), in which the gas bag volume (4221, 4222, 4223) or the inflation speed is adjusted after the gas bag (422, 423) has been inflated, depending on current data (a) of the impact detection device (1) and / or current data (x) one Device for occupant or object detection (2).

6. The method according to claim 5, in which the gas bag volume (422, 423) or the inflation speed is reduced after the initiation of inflation, if the current impact situation is classified as less severe or if the current occupant position is classified as harmless.

7. The method according to any one of claims 5 or 6, wherein the gas bag volume (422,423) or the inflation speed is increased after the initiation of the inflation, if the ac- current impact situation is classified as severe or if the current occupant position is classified as critical.