DE112004000041B4 - Accelerometer for an occupant protection system and method for deploying an occupant protection system - Google Patents

Abstract

Device for measuring acceleration for an occupant protection system of a vehicle (40), having a) a control device (30) arranged centrally in the vehicle (40), which has at least one central acceleration sensor (32), b) a sensor arrangement for detecting an impact with a direction in a movement plane (X, Y) of the vehicle, which is arranged outside the control unit (30) and comprises two devices (10, 20) for receiving an acceleration, c) wherein the first device (10) in the vicinity of a left vehicle outer skin and the second device (20) is arranged in the vicinity of a right-hand vehicle outer skin and symmetrically to the vehicle longitudinal axis (42), and d) each of the two devices (10, 20) has only exactly one acceleration sensor (12, 22) with a sensitivity direction (18, 28). , which is in the vehicle longitudinal axis (42) and the vehicle transverse axis (46) containing movement plane (X, Y) of the vehicle, and e) the sensitivity (18, 28) of each of the acceleration sensors (12, 22) is aligned in the plane of motion neither parallel nor perpendicular to the vehicle longitudinal axis (42), so that each acceleration sensor (12, 22) both accelerations in the direction parallel to the vehicle longitudinal axis (42) and f) wherein the control device (30) is designed to provide at least one sensor signal of one of the two acceleration sensors (12, 22) of the at least two devices (10, 20) and the sensor signal of the at least one central one Acceleration sensor (32) to generate a plausibility-based decision signal.

Description

The invention relates to an acceleration measuring device for an occupant protection system according to the preamble of claim 1 and to a method for deploying an occupant protection system according to claim 8.

For measuring, detecting or picking up (the expressions are used interchangeably hereinafter) of an acceleration or the acceleration effect occurring in a collision of a vehicle, various systems having different arrangements of acceleration sensors are known. A distinction is made between sensors arranged essentially centrally in the vehicle, which are often arranged together with a control unit in a central unit, and further sensors arranged in a decentralized or outsourced manner in the vehicle, the so-called satellite or assistance sensors, which are usually located close to the outer skin of the vehicle Vehicle are arranged. The acceleration-sensitive sensors are also referred to below as "acceleration sensors" or even more briefly as "sensors"; their sensitivity direction is synonymously also referred to as "sensitivity axis" or "effective direction". A direction parallel to the vehicle longitudinal axis in a forward direction of the vehicle is also referred to as "x-direction", and a direction parallel to a vehicle transverse axis also as "y-direction".

For example, to detect a head-on collision quickly, satellite sensors are mounted near the front of the vehicle, and then they are referred to as "upfront sensors". For reliable detection of a side impact, satellite sensors are correspondingly mounted in the side skin of the vehicle, for example in the door area, in which case one then speaks of side sensors.

Particularly in the event of a side impact, the time available for activating the restraining means from the first contact of a collision partner colliding laterally to the complete use of protection means is particularly short, due to the narrow crumple zone in the region of the vehicle side. Therefore, it is necessary to make a triggering decision for the insertion of a protective means such as an airbag as early as possible, and to address the corresponding protection means as quickly as possible. In this case, a final evaluation of the signals of the acceleration sensors (acceleration signals) is required at a time at which the acceleration caused by the acceleration has not yet reached its maximum value. Nevertheless, to make a reliable decision on the severity of the impact, such as the severity of the accident, and as far as possible on the type of impact or accident, the satellite sensors are provided. The central control unit evaluates the detected acceleration signals of the sensors provided in the satellite sensors and those of the centrally arranged sensors in order to make a triggering decision therefrom.

Various sensor arrangements with satellite sensors for sensing a side impact are known from the prior art, some of which are explained below by way of example.

The DE 44 25 846 A1 discloses a method for deploying side airbags in a safety device for motor vehicles wherein the information from sensors disposed centrally in the vehicle is linked to that from satellite sensors. Each of the sensor signals is checked to see if it exceeds certain predetermined thresholds and classified accordingly into acceleration classes. The class assignment of the sensor signals is evaluated by means of an evaluation matrix and, depending on the result thereof, optionally a trigger signal is generated. The triggering matrix determines which combination of the detected accelerations leads to a triggering signal and in which combinations no triggering of the restraint means takes place.

The DE 101 14 277 C1 proposes a system for detecting a side impact of a motor vehicle, in which a triggering decision based on the temporal waveforms is made by means of a data processing device. Satellite sensors are arranged asymmetrically with respect to the vehicle longitudinal axis, and the sensitivity directions of the sensors are aligned in either the vehicle longitudinal or the vehicle transverse direction. Due to the asymmetrical arrangement of the sensors can be closed due to geometric considerations and by means of the detected waveforms on the impact location and on the magnitude and direction of the momentum transfer.

The EP 866 971 B1 discloses a sensor arrangement for detecting an impact on a motor vehicle, in each of which left and right vehicle halves a respective satellite sensor comprising two acceleration sensors with differently oriented sensitivity axes is arranged, whereby each satellite sensor is sensitive to shocks acting on the vehicle (accelerations) at any angle with respect to the vehicle's longitudinal axis, in particular impacts from the front and from the side. The sensitivity directions are preferably aligned in a plane or direction defined by the vehicle longitudinal axis or the vehicle transverse axis.

The known acceleration measuring systems, in which the sensitivity of the Aligned sensors in vehicle longitudinal or transverse vehicle direction, have the disadvantage that only the acceleration signals or directions can be detected from a crash direction from the front or from the side.

From the DE 101 42 272 A1 is known a control unit for an occupant protection system of a vehicle, are connected to the arranged on opposite vehicle edges acceleration sensors that sense transversely to the vehicle longitudinal axis acting accelerations. The signals of these two acceleration sensors are set in relation to each other during a side impact in order to check their function. As a result, the acceleration sensor, which is usually still provided in the centrally arranged control unit, can be saved, which is provided for sensing in the y-direction. The two lateral acceleration sensors can, according to the DE 101 42 272 A1 also record acceleration values in the direction of the vehicle's longitudinal and transverse axes. In this case, they are inclined between 30 ° and 45 ° relative to the vehicle transverse axis. Although in this control unit, a saving in components, here at least one acceleration sensor can be achieved, however, is in occupant protection systems safety, especially the reliability of the controlling acting elements that ultimately cause the trigger decision in the foreground.

From the DE 101 53 015 A1 However, a triggering device for safety devices can be seen, in which on the one hand the central control unit should have no sensors, on the other hand, the respective decentralized sensor units but currently have a plurality of acceleration sensor elements to erzeuegn at each separate signals, which accelerate the vehicle in each case represent a different direction.

Object of the present invention is therefore to provide an acceleration measuring device for an occupant protection system and a method for triggering an occupant protection system with which a good tripping behavior of the occupant protection system can be achieved, in particular a particularly high level of security against possible false triggering is given, the effort and thus the However, reducing the cost of the system.

This object is achieved by an acceleration measuring device for an occupant protection system having the features of claim 1 and by a method for triggering an occupant protection system having the features of claim 8. Preferred embodiments of the invention will become apparent from the dependent claims.

An essential idea of the invention is to use only one per device inclined to the vehicle longitudinal and transverse axis outsourced sensor and to use its output signal in case of an impact to plausibility of a signal of a central acceleration sensor. Due to the inclined arrangement of the outsourced sensor provides a sufficiently strong for further processing or evaluation output signal both in a frontal as well as in a side impact. Especially in the event of a side impact, the outsourced sensor usually provides a much more meaningful signal than a centrally located sensor that is "further" away from the impact location. The signal of the outsourced sensor is therefore particularly well suited for plausibility and thus for increasing the triggering safety of an occupant protection system.

The invention now concretely relates to an acceleration measuring device for an occupant protection system of a vehicle, having a control device arranged centrally in the vehicle and having at least one central acceleration sensor, a sensor arrangement for detecting an impact with a direction in a plane of movement of the vehicle which is arranged outside the control device and at least two devices each for receiving an acceleration, wherein each of the at least two devices comprises only one acceleration sensor with a sensitivity direction that is in the vehicle longitudinal axis and vehicle transverse axis containing plane of movement of the vehicle, and the sensitivity direction of each of the acceleration sensors in the plane of motion neither parallel nor is oriented perpendicular to the vehicle longitudinal axis, so that each acceleration sensor both accelerations in the direction parallel to the vehicle longitudinal axis and parallel to the Can detect vehicle transverse axis. The control unit is designed to generate a plausibility-based decision signal with at least one sensor signal of one of the two acceleration sensors of the at least two devices and the sensor signal of the central acceleration sensor. Due to the special, deviating from the prior art orientation of the acceleration sensors, the sensor arrangement according to the invention has the advantage that each device (for example, a satellite sensor) can detect both acceleration effects in the vehicle longitudinal direction and in the vehicle transverse direction with only one acceleration-sensitive sensor element, this for each of the two devices taken individually. In addition, the signal from the sensor of the second device provides some redundancy in addition to the signal from the first device, as well as the possibility of further improving the plausibility check of the signal of the first device Sensor from the first device using the signal from the sensor of the second device.

The sensitivity direction of the first acceleration sensor of the first device and the sensitivity direction of the second acceleration sensor of the second device may have an angle α or β with respect to a forward direction of the vehicle characterized by an angle of 0 °, wherein the angles α and β are each in one range from above 0 ° to less than 90 °, in particular in a range of about 10 ° to about 80 °. As a result, the accelerations arising in the event of collisions in the front region of the vehicle can be detected particularly efficiently by each of the two acceleration sensors of the at least two devices, for example in the case of an impact of an object obliquely from the front on the vehicle.

A particular advantage is achieved when the angles α and β are each selected to be substantially equal to 45 °. Then, the sensitivity of the (single) sensor in each of the first and second accelerating action devices in the direction of the vehicle longitudinal axis, as occurring in a frontal collision, is about the same as the sensitivity in the direction of the vehicle transverse axis.

The devices are preferably located at two different locations in the vehicle, i. H. spatially far apart. The devices are preferably arranged symmetrically to the vehicle longitudinal axis. By choosing different locations in the vehicle on the one hand, the reliability is increased because it is unlikely that both sensors are simultaneously disturbed in their function, damaged or fail, and by outsourcing, for example, away from a central point in the vehicle on the other hand, the sensitivity for increases an impact in the direction from the location of the sensor to the central location in the vehicle, and increases the time available until the trigger decision is made.

In particular, the first device may be arranged in the vicinity of a left vehicle outer skin and the second device in the vicinity of a right vehicle outer skin. This increases the sensitivity to detect side impacts and increases the time available to make the deployment decision in side crashes. Instead of the door area, alternatively, the "outer floor area of the passenger compartment", such as the seat cross member under the seats, are selected.

In addition, the acceleration measuring device may comprise one, two or more further acceleration sensors, which are preferably arranged in pairs symmetrically to the vehicle longitudinal axis. This increases the redundancy and the options for plausibility checks.

Alternatively, at least one of the two devices can be arranged substantially centrally in the vehicle. For example, the device can be arranged in a central control unit, which reduces the wiring complexity in the vehicle.

A further aspect of the invention relates to an occupant protection system for a vehicle with an acceleration measuring device according to the invention and with at least one side impact protection means in each half of the vehicle relative to the vehicle longitudinal axis and at least one front impact protection means.

• (A) Ableiten eines ersten Freigabesignals durch Auswerten eines Sensorsignals des ersten Beschleunigungssensors oder des Sensorsignals des zweiten Beschleunigungssensors,
• (B) Ableiten eines zweiten Freigabesignals durch Auswerten des anderen Sensorsignals des ersten Beschleunigungssensors oder des zweiten Beschleunigungssensors, oder durch Auswerten eines Signals eines weiteren Beschleunigungssensors, und
• (C) Verknüpfen des ersten Freigabesignals mit zumindest dem zweiten Freigabesignal und Erzeugen eines Plausibilitätssignals zum Plausibilisieren eines Auslösesignals für Schutzmittel des Insassenschutzsystems.

The invention further relates to a method for triggering the above occupant protection system in a vehicle and with an acceleration measuring device according to the invention. The method of deploying an occupant protection system includes the steps

• (A) deriving a first enable signal by evaluating a sensor signal of the first acceleration sensor or the sensor signal of the second acceleration sensor,
• (B) deriving a second enable signal by evaluating the other sensor signal of the first acceleration sensor or the second acceleration sensor, or by evaluating a signal of a further acceleration sensor, and
• (C) linking the first enable signal with at least the second enable signal and generating a plausibility signal for plausibility of a trigger signal for protection means of the occupant protection system.

In an advantageous embodiment, deriving at least one of the enable signals by integrating an acceleration signal to generate a speed signal, comparing the speed signal to a threshold and generating the enable signal occurs when the speed signal exceeds the threshold.

Preferably, combining the first enable signal with at least the second enable signal comprises logically ANDing the first and second enable signals.

The first enable signal can be derived from the signal of the first acceleration sensor and the second enable signal can be derived from the signal of the second acceleration sensor.

Alternatively, the first enable signal can be derived from the signal of the first acceleration sensor and the second enable signal can be derived from the signal of a central acceleration sensor.

Further advantages and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments illustrated in the drawings.

In the description, in the claims, in the abstract and in the drawings, the terms and associated reference numerals used in the list of reference numerals recited below are used.

The drawings show in:

1 a sensor arrangement for a motor vehicle for detecting a collision according to the prior art, for side and front crash detection;

2 a further sensor arrangement for a motor vehicle for detecting a collision according to the prior art, with a difference from the arrangement of 1 other sensitivity direction of the acceleration sensors;

3 an embodiment of a sensor arrangement for a motor vehicle, for detecting an impact, as used for an acceleration measuring device according to the invention;

4 an embodiment of an acceleration measuring device for a motor vehicle, for detecting an impact according to the invention; and

5 a schematic diagram of an evaluation device or a method for evaluating the signals of two acceleration sensors according to the invention.

The 1 shows a possible sensor arrangement for a vehicle 40 , in particular motor vehicle, for detecting a collision according to the prior art, for the side and front crash detection. The sensor arrangement comprises a central unit 130 in which an acceleration sensor 132 and an evaluation device (not shown) are arranged, and outsourced satellite sensors. The satellite sensors include the satellite sensors mounted near the front of the vehicle 152 . 154 and 156 (Upfront sensors), each with an acceleration sensor whose direction of sensitivity in the forward direction 44 (X-direction) is aligned, which is why one speaks of an x-sensing. The sensitivity direction of the sensors in the upfront sensors 152 . 154 and 156 are in 1 indicated by arrows.

The satellite sensors further include the device mounted near the left outside skin of the vehicle 112 comprising two acceleration sensors, of which the sensitivity direction of the one sensor for x-sensing in the vehicle longitudinal direction and that of the other sensor for y-sensing in the vehicle transverse direction is aligned. The satellite sensors further comprise a device 114 leading to the device 112 is mounted substantially symmetrically to the vehicle longitudinal axis in the vicinity of the right outer side skin of the vehicle. The device 114 includes as well as the device 112 two acceleration sensors, of which the sensitivity direction of the one sensor for x-sensing in the vehicle longitudinal direction and that of the other sensor for y-sensing in the vehicle transverse direction is aligned. The sensitivity direction of the sensors in the devices 112 and 114 are in 1 indicated by arrows.

The sensitivity directions of the upfront sensors 152 . 154 and 156 are each aligned parallel to the vehicle longitudinal axis (in the x direction), and therefore can not detect acceleration effects from a lateral direction, ie, a direction in the vehicle transverse direction (y direction). The side satellites 112 and 114 can detect acceleration effects both in the vehicle longitudinal and transverse directions, because they each have two sensors with mutually orthogonal sensitivity directions, one of which is aligned in the x-direction and the other in the y-direction. The upfront sensors 152 . 154 and 156 have the task of enabling an additional plausibility check for types of impact in the vehicle's longitudinal direction.

2 shows another sensor arrangement for a motor vehicle according to the prior art. In particular shows 2 an alternative possibility for the arrangement of two acceleration sensors in a device. The sensor arrangement of the vehicle 40 from 2 alternatively shows a first device 134 and a second device 136 , in each of which two acceleration sensors are arranged. Of the two acceleration sensors of the device 134 is the sensitivity direction of the sensor for x-sensing in the vehicle longitudinal direction (forward direction 44 ) and that of the other sensor for y-sensing in the vehicle transverse direction. In contrast, of the two acceleration sensors of the device 136 the sensitivity direction of the one sensor in one Angle of -45 ° to the forward direction 44 (to the vehicle longitudinal direction) and the other sensor at an angle of + 45 ° to the forward direction 44 aligned. The sensitivity direction of the sensors in the devices 134 and 136 are in 2 indicated by arrows. The devices 134 and 136 For example, they are centrally located in the vehicle 40 arranged; however, the devices are 134 and 136 not limited to this arrangement and can be arranged at any position in the vehicle.

In aligning the sensitivity direction of the two acceleration sensors in the devices 134 . 136 from 2 In principle, all conceivable angular arrangements with different directions of the sensitivity directions are possible because by means of two acceleration sensors with different orientation of their sensitivity direction in the (in 2 horizontal plane), the acceleration effects can be detected from any direction in the plane and can be converted by converting the detected acceleration vectors into any other angular arrangement of two axes, also with different directions. In the prior art, the angular arrangements of two orthogonal sensitivity directions in the two in 2 shown variants proved to be advantageous. Thus, devices with two parallel to the vehicle longitudinal or vehicle transverse axis aligned sensors as in the device 134 in the pamphlets EP 0 434 679 B1 and US 5 737 224 A proposed. Devices with two diagonally (+ 45 ° and -45 °) to the vehicle longitudinal or vehicle transverse axis aligned sensors as in the device 136 are, however, for example, in the publications EP 0 292 669 B1 and EP 0 311 039 A2 proposed.

3 shows a sensor arrangement for a motor vehicle for detecting an impact, the first device 10 and a second device each having only a single acceleration sensor 12 respectively. 22 with a sensitivity direction 18 respectively. 28 include. The first sensitivity direction 18 the first device 10 and the second sensitivity direction 28 the second device 20 are in 3 represented by a thick arrow. The sensitivity directions 18 and 28 Both lie in the plane in which the vehicle moves and the vehicle's longitudinal axis 42 and the vehicle transverse axis 46 contains.

The sensitivity direction 18 the first device 10 is neither parallel nor perpendicular to the vehicle's longitudinal axis 42 aligned but in one by an angle α with respect to the forward direction (X direction) 44 determined direction. Likewise, the sensitivity direction 28 the second device 20 neither parallel nor perpendicular to the vehicle's longitudinal axis 42 aligned but in a by an angle β with respect to the forward direction (X direction) 44 determined direction. By the angle α or β with respect to the forward direction 44 characterized sensitivity direction 18 respectively. 28 is aligned, in particular at a certain minimum angular distance from the forward direction 44 of the vehicle 40 and at a certain minimum angular distance from the transverse direction 46 of the vehicle 40 that the acceleration sensor 12 respectively. 22 both accelerations in the direction parallel to the vehicle longitudinal axis 42 as well as perpendicular to it can safely capture.

The minimum angular distance of the sensitivity direction 18 the first device 10 in terms of a forward direction 44 is denoted by the symbol Δ1 and represents an angle lower limit 14 for the angle α dar.

Accordingly, the minimum angular distance of the sensitivity direction 18 in terms of the transverse direction 48 perpendicular to the forward direction 44 denoted by the symbol Δ2 and represents an upper angle limit 16 for the angle α. The same applies to the sensitivity direction 28 the second device 20 , The minimum angular distance of the sensitivity direction 28 the second device 20 in terms of the forward direction 44 is denoted by the symbol Δ3 and represents an angle lower limit 24 for the angle β. Accordingly, the minimum angular distance of the sensitivity direction 28 in terms of the transverse direction 48 perpendicular to the forward direction 44 denoted by the symbol Δ4 and represents an upper angle limit 26 for the angle β. The forward direction 44 of the vehicle 40 is marked by an angle of 0 °. Consequently, the angles of the sensitivity directions α and β of the acceleration sensors apply 12 respectively. 22 the first or second device 10 respectively. 20 : 0 ° + Δ1 = α = 90 ° - Δ2, resp. 0 ° + Δ3 = -β = 90 ° - Δ4.

Each of the sizes (minimum angular distances) Δ1, Δ2, Δ3 and Δ4 is greater than 0 °.

The angles α and β can, as explained above, be selected from a wide angular range, depending on which direction acceleration with high sensitivity is to be detected. For example, when collisions or crashes are to be detected obliquely from the front with a high sensitivity, and for the detection of pure side crashes, a lower sensitivity of the sensors 12 and 22 is sufficient, the angles α and β can be selected from a range of, for example, about 5 ° to about 20 °. The angles Incidentally, α and β do not have to be the same, but may have different values, depending on the purpose. If high sensitivity is required in the detection of side crashes, the angles α and β are more preferably selected in a range of about 70 ° to about 90 °. However, it is important when selecting the angles α and β that with the sensors 12 and 22 Both acceleration components in the direction of the vehicle longitudinal axis and transverse axis can be detected with a signal strength sufficient for further processing, in particular in order to make it plausible for the signals from centrally arranged acceleration sensors.

In the devices 10 and 20 For example, conventional acceleration sensors may be used as long as the acceleration sensors have a directional characteristic with a pronounced main sensitivity direction.

For example, the angle α may be approximately equal to 45 ° and the angle β approximately equal to -45 ° with respect to the vehicle longitudinal axis 42 to get voted. Then, the sensitivity of the (single) sensor in each of the first and second accelerating action devices in the direction of the vehicle longitudinal axis, as occurring in a frontal collision, is about the same as the sensitivity in the direction of the vehicle transverse axis.

The devices 10 . 20 can in two different places in the vehicle 40 be arranged. The devices 10 . 20 can also be symmetrical to the vehicle's longitudinal axis 42 be arranged. By choosing different locations in the vehicle 40 on the one hand the reliability of the sensors 12 . 22 increased, because it is unlikely that both sensors 12 . 22 are simultaneously disturbed in their function, damaged or fail, and by the removal, for example, away from a central point in the vehicle 40 On the other hand, the measuring sensitivity for impact in the direction of the mounting location of a sensor 12 . 22 to the central location in the vehicle 40 is increased and the time available until the trigger decision of the retention means is made longer. It is particularly advantageous if the first device 10 near a left vehicle skin and the second device 20 is arranged near a right vehicle skin, because in a side impact, the crumple zone is particularly small.

It is not necessary for the functioning of the teaching according to the invention, but the devices 10 . 20 advantageous also symmetrical to the vehicle longitudinal axis 42 to be ordered.

The above-mentioned advantage of the invention is also obtained if at least one of the two devices 10 . 20 essentially centrally located in the vehicle. Then, the centrally arranged of the two devices can be arranged in a housing together with an evaluation unit for the signals generated by acceleration sensors.

The sensor arrangement may additionally comprise one, two or more further acceleration sensors (not shown), wherein the sensors are preferably arranged in pairs and / or symmetrically to the vehicle longitudinal axis.

4 1 shows an acceleration measuring device with a sensor arrangement for a motor vehicle for detecting an impact, in addition to those in FIG 3 described devices 10 and 20 a central in the vehicle 40 arranged control unit 30 comprising a central acceleration sensor disposed therein 32 has and with a microprocessor μP 34 to evaluate the from the acceleration sensors 12 . 22 and 32 generated electrical signals is communicatively connected. To supply the signals from the sensors to the microprocessor 34 the latter is electric with the acceleration sensors 12 . 22 and 32 connected. Through the central acceleration sensor 32 can in the evaluation and control unit 30 a plausibility-based decision signal is generated to trigger protection means. In the process, the plausibility of the signal of the central acceleration sensor is checked 32 additionally from the evaluation of the signals of the sensors 12 . 22 obtained information about the nature, strength, direction, etc. of the acceleration effect, for example, the impact used. In the embodiment of 4 allow the two sensors 12 and 22 a plausibility check of the central acceleration sensor 32 and thus cause an increase in the reliability of the triggering decision

The 5 shows a block diagram of an evaluation device whose operation and a principle of a realized therein method (algorithm) for evaluating the acceleration signals and generating a trigger signal will be explained below. In a first evaluation path or evaluation channel, the output signal a1 (t) of a first acceleration sensor, here the sensor 12 the first device 10 , a device 50 supplied for integration. At the output of the integration device 50 a speed signal v1 (t) is available for further evaluation. The speed signal v1 (t) becomes a device 52 supplied for comparison. The comparison device 52 will also be a threshold 56 supplied by an adjusting device 54 determined variably Requirements such as the speed of the vehicle can be adjusted accordingly and is used as Kritizismuskriterium or as a triggering threshold. At the exit of the comparison device 52 when the speed signal v1 (t) becomes the threshold 56 exceeds, a first enable signal 58 generated by an occupant protection device 70 is supplied. The first enable signal 58 is for a plausibility check with at least one further enable signal from another, independent evaluation channel for generating a trigger signal 74 for the restraining means of the occupant protection device 70 connected.

Analogously to the first evaluation channel, the output signal a2 (t) of a second acceleration sensor, in this case the central acceleration sensor, is produced in a second evaluation path (evaluation channel) 32 , a device 60 supplied for integration. At the output of the integration device 60 a speed signal v2 (t) is available for further evaluation. The speed signal v2 (t) becomes a device 62 supplied for comparison. The comparison device 62 will also be a threshold 66 supplied by an adjusting device 64 can be variably adjusted according to the requirements and is used as Kritizismuskriterium or as a triggering threshold. At the exit of the comparison device 62 when the speed signal v2 (t) becomes the threshold 66 exceeds, a second enable signal 68 generated, which is also the occupant protection device 70 is supplied. The second enable signal 68 is for the plausibility check with the first enable signal from the first evaluation channel in the device 72 for generating the triggering signal 74 connected.

In the second evaluation channel, instead of the acceleration signal generated by the centrally arranged acceleration sensor 32 or generated by a further acceleration sensor, also the signal of the second acceleration sensor 22 the second device to be evaluated.

In the example of in 5 shown evaluation direction causes the linking device 72 for plausibility, a logical "AND" combination of the first and second enable signal 58 and 68 , It is also possible to use links other than the AND link.

It is also possible to provide more than two evaluation channels, for example by continuing to include in the plausibility check the signal from the sensor 22 flows. An associated plausibility check can accordingly also include a combination of more than two release signals generated in the evaluation channels.

For completeness it should be mentioned that the plausibility and thus caused generation of the trigger signal not on the logical AND operation of the two enable signals 58 . 68 is limited, but also by a comparison of the independent unprocessed acceleration signals a1 (t) and a2 (t) and / or further processed working signals from the two Auswertekanälen can be performed.

LIST OF REFERENCE NUMBERS

10

first device

12

first acceleration sensor

14

Direction to the lower limit angle Δ1 of the first sensitivity direction

16

Direction to the upper limit angle Δ2 of the first sensitivity direction

18

first sensitivity direction (of the first acceleration sensor)

20

second device

22

second acceleration sensor

24

Direction to the lower limit angle .DELTA.3 of the second sensitivity direction

26

Direction to the upper limit angle Δ4 of the second sensitivity direction

28

second sensitivity direction (of the second acceleration sensor)

30

centrally located control unit

32

central acceleration sensor

40

vehicle

42

vehicle longitudinal axis

44

Forward direction (X direction) of the vehicle

46

Vehicle transverse axis

48

Transverse direction (Y direction) of the vehicle

α

Angle of the first sensitivity direction

Δ1

Lower limit angle of the first sensitivity direction

Δ2

Upper limit angle of the first sensitivity direction

β

Angle of the second sensitivity direction

Δ3

Lower limit angle of the second sensitivity direction

Δ4

Upper limit angle of the second sensitivity direction

50

Integration device in the first evaluation channel

52

Comparative device in the first evaluation channel

54

Adjustment device in the first evaluation channel

56

Threshold in the first evaluation channel

58

Enable signal of the first evaluation channel

60

Integration device in the second evaluation channel

62

Comparative device in the second evaluation channel

64

Adjustment device in the second evaluation channel

66

Threshold in the second evaluation channel

68

Enable signal of the second evaluation channel

70

Occupant protection device

72

Plausibilisierungsvorrichtung

74

trigger signal

112, 114

Side-by-side satellite sensors of the prior art

130

central processing unit

132

accelerometer

152, 154, 156

Satellite sensor (upfront sensor) according to the prior art

Claims (12)

Device for measuring the acceleration of an occupant protection system of a vehicle ( 40 ), with a) one centrally located in the vehicle ( 40 ) arranged control unit ( 30 ), the at least one central acceleration sensor ( 32 b) a sensor arrangement for detecting an impact with a direction in a movement plane (X, Y) of the vehicle which is outside the control device ( 30 ) and two devices ( 10 . 20 ) for picking up each acceleration, c) the first device ( 10 ) in the vicinity of a left vehicle skin and the second device ( 20 ) in the vicinity of a right-hand vehicle outer skin and symmetrically to the vehicle longitudinal axis ( 42 ) and d) each of the two devices ( 10 . 20 ) only exactly one acceleration sensor ( 12 . 22 ) with a sensitivity direction ( 18 . 28 ), which in the vehicle longitudinal axis ( 42 ) and the vehicle transverse axis ( 46 ) includes the movement plane (X, Y) of the vehicle comprises, and e) the sensitivity direction ( 18 . 28 ) each of the acceleration sensors ( 12 . 22 ) in the plane of movement neither parallel nor perpendicular to the vehicle longitudinal axis ( 42 ), so that each acceleration sensor ( 12 . 22 ) both accelerations in the direction parallel to the vehicle longitudinal axis ( 42 ) as well as parallel to the vehicle transverse axis ( 46 ), f) the control unit ( 30 ) is designed to be connected to at least one sensor signal of one of the two acceleration sensors ( 12 . 22 ) of the at least two devices ( 10 . 20 ) and the sensor signal of the at least one central acceleration sensor ( 32 ) to generate a decision signal based on plausibility. Device according to claim 1, characterized in that the sensitivity direction ( 18 ) of the first acceleration sensor ( 12 ) of the first device ( 10 ) and the sensitivity direction ( 28 ) of the second acceleration sensor ( 22 ) of the second device ( 20 ) an angle α and β with respect to a forward direction characterized by an angle of 0 ° ( 44 ) of the vehicle ( 40 ), wherein the angles α and β are each in a range of about 0 ° to less than 90 °, in particular in a range of about 10 ° to about 80 °. Apparatus according to claim 1 or 2, characterized in that the angles α and β are each substantially equal to 45 °. Device according to one of claims 1 to 3, characterized in that the devices ( 10 . 20 ) symmetrical to the vehicle longitudinal axis ( 42 ) are arranged. Device according to one of claims 1 to 4, characterized in that the first device ( 10 ) in the vicinity of a left vehicle skin and the second device ( 20 ) are arranged near a right vehicle outer skin. Device according to one of claims 1 to 5, characterized in that it additionally comprises one, two or more further acceleration sensors. Occupant protection system for a vehicle ( 40 ) with a device according to one of claims 1 to 6 with at least one side impact protection means in each half of the vehicle with respect to the vehicle longitudinal axis ( 42 ) and at least one front impact protection agent. Method for triggering an occupant protection system ( 70 ) according to claim 7 with a device according to one of claims 1 to 6 in a vehicle ( 40 ), comprising the steps of (A) deriving a first enable signal ( 58 ) by evaluating a sensor signal of the first Acceleration sensor ( 12 ) or the second acceleration sensor ( 22 ), (B) deriving a second enable signal ( 68 ) by evaluating the other sensor signal of the first acceleration sensor ( 12 ) or the second acceleration sensor ( 22 ), or by evaluating a signal of another acceleration sensor ( 32 ), (C) linking the first enable signal ( 58 ) with at least the second enable signal ( 68 ) and generating a plausibility signal for plausibility of a trigger signal ( 74 ) for occupant protection system ( 70 ). Method according to Claim 8, characterized in that the derivation of at least one of the enable signals ( 58 . 68 ) comprises: integrating an acceleration signal a1 (t) to generate a speed signal v1 (t), comparing the speed signal v1 (t) to a threshold ( 56 ) and generating the enable signal when the speed signal v1 (t) exceeds the threshold ( 56 ) exceeds. Method according to claim 8 or 9, characterized in that the linking of the first enable signal ( 58 ) with at least the second enable signal ( 68 ) a logical AND connection of the first and second enable signal ( 58 . 68 ). Method according to one of claims 8 to 10, characterized in that the first enable signal ( 58 ) from the signal a1 (t) of the first acceleration sensor ( 12 ) and the second enable signal ( 68 ) from the signal a2 (t) of the second acceleration sensor ( 22 ) is derived. Method according to one of claims 8 to 11, characterized in that the first enable signal ( 58 ) from the signal a1 (t) of the first acceleration sensor ( 12 ) and the second enable signal ( 68 ) from the signal of a central acceleration sensor ( 32 ) is derived.

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