DE19827557B4 - Method for detecting a vehicle crash - Google Patents

Abstract

Method for recognizing a vehicle crash, wherein depending on the acceleration behavior of the vehicle, a decision is made to trigger one or more restraint devices, characterized in that the behavior of at least one sensor or actuator (K1, ..) which responds to accelerations and is provided for the engine control. ., KN, SW, LM, DK, FP, KD) is recorded and evaluated and that in the case of behavior characteristic of a crash, this is used as a criterion for triggering the restraint device (s).

Description

The present invention relates to a method for detecting a vehicle crash, depending on from the vehicle's acceleration behavior to the triggering of a or more restraint devices is decided.

Such a method is, for example, from the international patent application WO 89/11986 known. To one Vehicle crash reliable one or more acceleration sensors can be seen in the vehicle installed with a sudden accelerating change or a delay of the vehicle is measured. Whether the acceleration or deceleration of the Vehicle is due to a vehicle crash that is so severe the existence or more restraint devices (Airbags, belt tensioners) triggered is to be determined by a threshold decision, which the output signals of the acceleration sensors are subjected to. By equipping the vehicle with sensors specifically for crash detection are provided increases the effort of the restraint system. To be as high as possible reliability to achieve in the crash detection, you can not avoid that Examine the output signals of the crash sensors for plausibility. Also to that would be an additional Circuitry required.

The invention is therefore the object based on specifying a method of the type mentioned at the beginning with which can be reduced in the area of crash sensors.

Advantages of invention

The task mentioned is with the Features of claim 1 solved in that the behavior at least one that responds to accelerations and is provided for the engine control Sensor or actuator detected and is evaluated and that at one for a crash characteristic behavior this as a criterion for triggering the restraint device (s) is used. For the Crash detection so are existing in the vehicle anyway, on accelerations reacting components are used, so that additional crash sensors are saved can be.

Advantageous further training and versions the invention emerge from the subclaims.

Thereafter, the restraint device (s) will only be triggered causes if at least two sensors or actuators are characteristic of a crash Show behavior.

The behavior of at least one Sensors or actuators can also be used for the plausibility check of Crash sensors installed in the vehicle can be used.

For the crash detection can e.g. the signal of at least one knock sensor be evaluated. Or there will be signals from at least two Knock sensors assigned to different cylinders are evaluated and only then is there a trigger criterion before if at least two knock sensor signals have a similar crash-characteristic behavior demonstrate.

This can also be used for crash detection Signal from a rough road sensor or the signal from a load sensor (e.g. air mass sensor, air volume sensor, intake manifold pressure sensor) or the. Movement of the throttle valve, or the movement of the accelerator pedal or the signal of a fuel pressure sensor can be evaluated.

For the evaluation can be the output signal level of at least one Sensor or actuator subjected to a threshold decision become. Or it becomes the output signal of the at least one sensor or Stellers subjected to a spectral analysis and the determined Spectrum is characterized by one or more of different types of crash Spectra compared and given a similarity measure on triggering the Retaining device (s) decided.

Using several in the drawing shown versions the invention is closer below explained. Show it:

1 2 shows a block diagram of a sensor signal evaluation of a first type,

2 a block diagram of a sensor signal evaluation of a second type and

3 a block diagram showing the networking of multiple sensor signals.

For the engine control, there are several sensors or actuators in a vehicle, which inevitably also react to accelerations of the vehicle, especially if these suddenly increase or decrease, as in a crash. Such sensors or actuators include, for example, one or more knock sensors arranged on the engine block, which, as in FIG US 4,418,567 described, serve to detect the knock resulting from the sudden combustion of mixture parts in the cylinders. Another sensor that responds to vehicle accelerations is a rough road sensor. This sensor, which is very sensitive to jerky vehicle movements, is used to hide the misfire detection in OBDII systems. Rough distance sensors are for example from the US 5,357,788 and the DE 42 29 487 A1 known.

Load sensors also react are arranged in the intake manifold of the engine, on vehicle accelerations. The load sensors include e.g. Air volume, air mass or intake manifold pressure sensors. These types of sensors are in “Bosch Technical briefing, Motronic engine management ", second edition August 93, pages 28 to 32. Also actuators, like the throttle valve and the accelerator pedal show reactions due to strong vehicle accelerations.

If a fuel pressure sensor (see DE 195 47 647 A1 ) is present, his reaction to vehicle accelerations could also be used to detect crashes.

In the 1 and 2 Two exemplary embodiments of a signal evaluation circuit SS for the output signal s of one of the aforementioned sensors or actuators SE are shown. At the in 1 Embodiment of a signal evaluation circuit SS shown, the output signal s of the sensor or actuator SE is first fed to an amplifier VS. Interfering signal components are then suppressed in a bandpass filter BP. The envelope of the filtered signal is then determined by a rectifier GR and then integrated into IT. The integrator IT can also be omitted. At the end, a threshold value decision SES takes place, the threshold value decision maker SES only outputting an output signal a if the input signal supplied to it exceeds a predetermined threshold. This threshold has previously been determined empirically and depends on how the output signal level s of the respective sensor or actuator SE behaves in the event of a crash or also in the case of different types of crashes. If the sensor or the actuator shows behavior characteristic of a crash, the output signal a appears at the output of the threshold value decider SES, which can be used as a criterion for triggering one or more restraint devices in the vehicle.

At a second in 2 In the illustrated embodiment of the signal evaluation circuit SS, the signal s of the respective sensor or actuator SE is subjected to a spectral analysis SA (for example after the Fast Fourier Transformation) after the amplification VS and the bandpass filtering BP. The spectrum of the signal s determined in this way is then compared in a switching block SV with one or more spectra characteristic of different types of crash. These characteristic spectra, which the output signal s of the respective sensor or actuator shows in one or different types of crashes, are determined empirically beforehand and stored in a memory in the switching block SV. A similarity comparison takes place between the measured spectrum and the stored characteristic spectra. If a predetermined degree of similarity of the measured spectrum with or with one of the stored crash-characteristic spectra is achieved, an output signal a is emitted which signals a detected vehicle crash and serves as a criterion for triggering one or more restraint devices.

As already explained above, there are a large number of sensors or actuators responsible for the motor control, which show an acceleration-dependent behavior. In the 3 a number of them are shown with evaluation circuits connected to them, which operate according to one of the exemplary embodiments described above. With K1, ..., KN knock sensors are meant, one of which can be present per cylinder of the engine. Signal evaluation circuits SSK1, ..., SSKN are connected to it. SW is a rough road sensor with its signal evaluation circuit SSW. LM is a load sensor arranged in the intake manifold of the engine, for example an air mass sensor or an air quantity sensor or an intake manifold pressure sensor. The SSLM signal evaluation circuit is connected to it. Switch block DK determines the movement of the throttle valve. The movement of the throttle valve is usually detected by means of a potentiometer. The SSDK signal evaluation circuit is connected to it. The evaluation of the movement of the accelerator pedal is indicated by the switching block FP. The movement of the accelerator pedal is also usually determined using a potentiometer. The signal evaluation circuit SSFP is connected to the switching block FP. The switching block KD stands for a fuel pressure sensor, the output signal of which is processed by the signal evaluation circuit SSKD.

As with the 1 and 2 explained by way of example, a triggering criterion for one or more restraint devices can be derived from one of the sensors or actuators alone. A vehicle crash can, however, be detected with considerably greater reliability if the output signals of the signal evaluation circuits are linked to one another by a plurality of sensors or actuators, and only if all or at least the majority of which signal a vehicle crash is decided for a crash event ,

In the 3 is shown as an example that the output signals aK1, ..., aKN of the signal evaluation circuit SSKN from several knock sensors K1, ..., KN in SSK1, ..., an AND gate U1 are linked together and only then a signal a1, the can be used as a trigger criterion, is given if all knock sensors K1, ..., KN show a characteristic of a crash.

In the exemplary embodiment shown, all other output signals aSW, aLM, aDK, aFP and aKD of the signal evaluation circuits SSSW, SSLM, SSDK, SSFP and SSKD of the rough path sensor SW, the load sensor LM and the throttle valve position DK are via a second AND gate U2 with the signal a1 , the accelerator pedal position FP and the fuel pressure sensor KD linked together. An output signal a2 therefore only appears at the AND gate U2 if all the sensors or actuators exhibit behavior characteristic of a crash. The output signal a2 can now be fed directly as a triggering criterion to a triggering control device for the restraint device or devices. The sensors or actuators K1, ..., KN, SW, LM, DK, FP, KD either replace the otherwise existing crash sensors, so that the signal a2 can be fed directly to a trigger control unit as a trigger criterion. Like in the 3 shown, the signal a2 can also be used for the plausibility check of the output signal as of one or more additionally available crash sensors CS. This plausibility check, which in the simplest case is carried out using an AND gate, takes place in the switching block PP. If the plausibility check is successful, the switching block PP emits an output signal a1, which ultimately signals a triggering control unit that the restraint device or devices are to be triggered due to a vehicle crash.

Notwithstanding that in the 3 The exemplary embodiment shown, in which the signals from all sensors or actuators are linked to one another in order to obtain a triggering criterion, can be used either for individual or groups of sensors or actuators for deriving a triggering criterion. Any combination of sensors or actuators would be possible in order to derive a triggering criterion from their crash-characteristic behavior.

Claims (13)

Method for recognizing a vehicle crash, a decision being made as a function of the acceleration behavior of the vehicle to trigger one or more restraint devices, characterized in that the behavior of at least one sensor or actuator (K1, ..) which responds to accelerations and is provided for the engine control. ., KN, SW, LM, DK, FP, KD) is recorded and evaluated and that in the case of behavior characteristic of a crash, this is used as a criterion for triggering the restraint device (s). A method according to claim 1, characterized in that only if at least two sensors or actuators (K1, ..., KN, SW, LM, DK, FP, KD) one for one Crash characteristic behavior show the triggering of the restraint (s) causes becomes. A method according to claim 1 or 2, characterized in that that this Behavior of the at least one sensor or actuator (K1, ..., KN, SW, LM, DK, FP, KD) for the plausibility check (PP) of crash sensor signals (as) is used. A method according to claim 1, characterized in that this Signal of at least one knock sensor (K1, ..., KN) is evaluated. A method according to claim 4, characterized in that the Signals from at least two different cylinders assigned Knock sensors (K1, ..., KN) are evaluated and that only then trigger criterion is present when at least two knock sensor signals are of the same type Show crash characteristic behavior. A method according to claim 1, characterized in that this Signal from a rough road sensor (SW) is evaluated. A method according to claim 1, characterized in that this Signal from an air mass or air volume sensor (LM) evaluated becomes. A method according to claim 1, characterized in that this Signal of an intake manifold pressure sensor (LM) is evaluated. A method according to claim 1, characterized in that the Movement of the throttle valve (DK) is evaluated. A method according to claim 1, characterized in that the Movement of the accelerator pedal (FP) is evaluated. A method according to claim 1, characterized in that this Signal of a fuel pressure sensor (KD) is evaluated. A method according to claim 1, characterized in that the Output signal level of the at least one sensor or actuator (K1, ..., KN, SW, LM, DK, FP, KD) subjected to a threshold decision (SES) becomes. A method according to claim 1, characterized in that this Output signal of the at least one sensor or actuator (K1, ..., KN, SW, LM, DK, FP, KD) is subjected to a spectral analysis (SA) and that this determined spectrum with one or more characteristic for different types of grass Spectra is compared and given a similarity measure on triggering the restraint (s) is decided.