JP2007237835A - Failure detecting device of occupant restraining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a failure detecting device of an occupant restraining device preventing the occurrence of reset failure of a collision detecting sensor. <P>SOLUTION: The failure detecting device of an occupant restraining device comprises the collision detecting sensor 2 installed in front of a vehicle and at a position to which vibrations are transmitted at the time of the operation of a horn, and a micro computer 1 restraining an occupant by judging to deploy an airbag when the collision detecting sensor 2 detects the collision of a vehicle. An airbag control unit 1 detects the accumulated operation frequency of the horn 3, and sets a diagnosis threshold value determining fault possibility of a connector resistance value of the collision detecting sensor 2 according to the accumulated operation frequency of the horn 3. When an actual connector resistance value exceeds the diagnosis threshold value, the possibility of the occurrence of the reset failure is high. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a failure detection device for an occupant restraint device that detects a collision by a collision detection sensor provided in front of a vehicle and restrains the occupant from an impact caused by the collision.

Conventionally, in an airbag system that restrains an occupant in the event of a vehicle collision, an airbag deployment decision is made using information from a collision detection sensor installed in the engine room and an airbag control unit installed in the vehicle compartment. An airbag device that performs the above-mentioned is known from Patent Document 1 below. In this airbag apparatus, when the collision detection sensor and the safing sensor in the airbag control unit are both turned on, or the gravity sensor of the airbag control unit is turned on and the safing sensor of the airbag control unit is When turned on, the airbag is deployed.
Patent No. 3690232

  However, in the airbag device described above, since the collision detection sensor is provided in the engine room in order to improve the collision detection accuracy, the position is close to the horn provided in the engine room. For this reason, the collision detection sensor is subjected to vibration when the horn is operated, and a phenomenon occurs in which the contact terminals of the connector for connecting the collision detection sensor and the airbag control unit are rubbed by the vibration.

  Then, an oxide film is generated on the surface of the connector contact terminal in the collision detection sensor, the electric resistance value increases, and a reset failure may occur in which the detection value of the collision detection sensor is not accurately transmitted to the airbag control unit. In other words, when the electrical resistance value of the connector terminal increases, the resistance value of the collision detection sensor itself increases, that is, the collision detection sensor may be erroneously recognized as malfunctioning. It is necessary to replace both the collision detection sensor and the harness connected to the connector as a set, and it may be necessary to replace the airbag control unit.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and an object thereof is to provide a failure detection device for an occupant restraint device that prevents the occurrence of a reset failure of a collision detection sensor.

  In the present invention, a collision detection sensor installed at a position in front of the vehicle where vibration is transmitted when the horn is operated, and when a collision of the vehicle is detected by the collision detection sensor, the airbag is determined to be deployed. A failure detection device for an occupant restraint device comprising a microcomputer for restraining an occupant, a horn operation frequency detection means for detecting a cumulative operation frequency of the horn, and a cumulative operation frequency of the horn detected by the horn operation frequency detection means A diagnostic threshold value setting means for setting a diagnostic threshold value for determining the possibility of failure of the collision detection sensor according to the input, an input means for inputting a resistance value between the input and output parts of the collision detection sensor, and a diagnosis A determination unit configured to determine a failure of the collision detection sensor by comparing the diagnostic threshold set by the threshold setting unit with the resistance value input by the input unit; It allows to solve the problems described above.

  According to the failure detection device for an occupant restraint device according to the present invention, the resistance value of the collision detection sensor can be determined by setting a diagnostic threshold value according to the cumulative operating frequency of the horn. It is possible to prevent the occurrence of a reset failure of the collision detection sensor due to the increase of.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The present invention is applied, for example, to an occupant restraint device configured as shown in FIG.

  This occupant restraint device includes an airbag control unit 1 that is a microcomputer installed in a vehicle interior, a collision detection sensor 2 that is installed in the engine room and in front of the vehicle, and a vehicle detection device that is in front of the vehicle in the same manner as the collision detection sensor 2. The installed horn 3 is connected to a horn switch 4 that is operated when a vehicle occupant emits a horn sound.

  As shown in FIG. 2, the collision detection sensor 2 and the horn 3 are disposed in front of the vehicle in the same manner as the cooling system parts 11 such as an air conditioner condenser and a radiator. The cooling system component 11 is supported by a radiator support upper 13 and radiator support sides 12 and 13 which are radiator supports. The collision detection sensor 2 is attached to the radiator support upper 13, and the left and right horns 3 </ b> A and 3 </ b> B are attached near both ends of the radiator support upper 13 with the collision detection sensor 2 interposed therebetween. Since the collision detection sensor 2 and the left and right horns 3A and 3B are attached to the radiator support upper 13 which is the same member, when the left and right horns 3A and 3B emit sound, the collision detection sensor 2 is vibrated. Communicated. Even if the collision detection sensor 2 or the horns 3 </ b> A, 3 </ b> B are attached to the radiator support side 12 or the vicinity of these parts, the vibration of the horn 3 is transmitted to the collision detection sensor 2.

  The collision detection sensor 2 is connected to the airbag control unit 1 with a harness by a connector. The harness connecting the airbag control unit 1 and the collision detection sensor 2 can be replaced by removing the connector from the collision detection sensor 2. When the collision detection sensor 2 detects a forward collision of the vehicle, the collision detection sensor 2 supplies a signal indicating that to the airbag control unit 1.

  When the airbag control unit 1 receives a signal from the collision detection sensor 2 that detects a forward collision of the vehicle, the airbag control unit 1 uses the signal to determine deployment of an airbag (not shown). The airbag control unit 1 also performs failure determination processing for the collision detection sensor 2.

  As shown in FIG. 3, the failure determination process of the airbag control unit 1 includes a diagnostic threshold value for determining a reset failure with respect to the resistance value of the connector of the collision detection sensor 2 actually measured. deep. When it is determined that the actual connector resistance value of the collision detection sensor 2 is lower than the diagnostic threshold value, it is determined that no reset failure has occurred, and it is determined that the connector resistance value is higher than the diagnostic threshold value. Is determined that a reset failure has occurred. This diagnosis threshold value is set to a resistance value lower than a connector resistance value at which the collision detection sensor 2 is determined to have a reset failure because the connector of the collision detection sensor 2 is rubbed by vibration of the front part of the vehicle based on data such as experiments. Has been. The diagnostic threshold is set to a value that may cause a reset failure if the connector resistance value becomes higher than this.

  The airbag control unit 1 changes the diagnostic threshold according to the frequency with which the horn 3 is operated. The airbag control unit 1 changes the diagnosis threshold value lower as the cumulative operation frequency of the horn 3 is higher in accordance with the past cumulative operation frequency of the horn 3. As a result, as shown in FIG. 2, the horn 3 is installed in the vicinity of the collision detection sensor 2, and the higher the cumulative operation frequency of the horn 3, the more reliably it is determined that there is a risk of reset failure of the collision detection sensor 2. It can be so.

  The air bag control unit 1 may obtain the cumulative operation frequency of the horn 3 by a counter (not shown) in the airbag control unit 1 in order to obtain the cumulative operation frequency of the horn 3. The cumulative operating frequency may be obtained. Thus, as shown in FIG. 4, in order to cope with the rise of the connector resistance value in a 2 o'clock curve in proportion to the number of vibrations of the connector of the collision detection sensor 2 and the vibration time, the airbag control unit 1 Can change the diagnostic threshold value in a quadratic curve according to the count of the cumulative number of operations of the horn 3.

  As shown in FIG. 5, the airbag control unit 1 has a diagnostic threshold value that is lower than the connector resistance value at the time of reset failure by a predetermined value at the initial stage when the cumulative operation count of the horn 3 is small. If the cumulative number of operations of the horn 3 reaches a times, the diagnosis threshold value is lowered, and if the cumulative operation number of the horn 3 is more than b times, the diagnosis threshold value is further decreased. Reduce. Similarly, the diagnostic threshold is lowered as the cumulative operating time of the horn 3 becomes longer.

  As shown in FIG. 6, the failure detection process of the airbag control unit 1 first determines whether or not the IGN switch is on in step S1, and if the IGN switch is on. In step S2, the cumulative number of operations of the horn 3 from the time when the IGN switch was previously turned on until the time when the IGN switch was determined to be on in step S1 is read from a memory (not shown).

  Next, in step S3, the air bag control unit 1 determines whether or not the cumulative number of operations of the horn 3 read in step S2 is b times or more. If it is determined that the number is b times or more, in step S7, Set the diagnostic threshold to the minimum value of b times or more. Further, in the next step S4, where it is determined that the cumulative number of operations of the horn 3 is not more than b times, it is determined whether the cumulative number of operations of the horn 3 is a times less than b times.

  When it is determined that the cumulative number of operations of the horn 3 is a times or more, in step S6, a diagnosis threshold value is set at a times higher than the diagnosis threshold value at b times or more set in step S7. If it is determined that the cumulative number of operations of the horn 3 is within a times, the initial diagnosis threshold value is maintained in step S5.

  Next, in step S8, the airbag control unit 1 inputs the actually measured connector resistance value. In step S9, any of the diagnostic threshold values set in steps S5 to S7 is equal to or less than the actual connector resistance value. It is determined whether or not. If the diagnostic threshold value is less than or equal to the connector resistance value, it is determined in step S10 that there is no risk of a reset failure due to an increase in the connector resistance value, and the process proceeds to step S13.

  On the other hand, if it is determined that the diagnostic threshold value is not less than or equal to the actual connector resistance value, it is determined in step S11 that there is a risk of reset failure, a warning is given to the user in step S12, and the process proceeds to step S13. Proceed.

  In step S13, the airbag control unit 1 resets the cumulative number of operations of the horn 3 and ends the failure detection process. Thereafter, the airbag control unit 1 starts counting the cumulative number of operations of the horn 3 from zero.

  When such an occupant restraint device has an actual connector resistance value, which is a resistance value at a collision detection sensor connecting portion of a harness connecting the collision detection sensor 2 and the airbag control unit 1, higher than a diagnosis threshold value, An indicator such as an instrument panel (not shown) is notified that there is a risk of a reset failure that increases the connector resistance value of the collision detection sensor 2. Thus, the operator can eliminate the need to replace the airbag control unit 1 by exchanging the collision detection sensor 2 and the harness as a set. In addition, there is a risk of a reset failure of the collision detection sensor 2 on the screen of the diagnostic terminal carried by the operator instead of an indicator such as an instrument panel, and the collision detection sensor 2 and the airbag control unit 1 are connected. It is also possible to display a message prompting replacement of the harness to be performed.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

  In the above-described example, the diagnostic threshold value is changed by counting the cumulative number of operations of the horn 3 from when the IGN switch (not shown) was turned on last time until it is turned on this time. The accumulated operating time of the horn 3 from the time when the previous IGN switch is turned on to the time when this IGN switch is turned on may be used to change the diagnostic threshold, or from the time when the collision detection sensor 2 is installed until the present time. The diagnostic threshold value may be changed according to the cumulative number of operations of the horn 3 and the cumulative operation time.

It is a block diagram which shows the structure of the passenger | crew restraint apparatus containing the airbag control unit to which this invention is applied. It is a perspective view which shows the attachment structure of a collision detection sensor and a horn. It is a figure which shows the relationship between the cumulative operating frequency of a horn, and a diagnostic threshold value. It is another figure which shows the relationship between the cumulative operating frequency of a horn, and a diagnostic threshold value. It is another figure which shows the relationship between the cumulative operating frequency of a horn, and a diagnostic threshold value. It is a flowchart which shows the process sequence of the failure detection process in the airbag control unit to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airbag control unit 2 Collision detection sensor 3 Horn 4 Horn switch 11 Cooling system parts 12 Radiator support side 13 Radiator support upper

Claims (5)

A collision detection sensor installed at a position in front of the vehicle where vibrations are transmitted when the horn is activated, and when a collision of the vehicle is detected by the collision detection sensor, the airbag is deployed and the occupant is restrained. A failure detection device for an occupant restraint device comprising a microcomputer,
Horn operating frequency detection means for detecting the cumulative operating frequency of the horn;
A diagnostic threshold value setting means for setting a diagnostic threshold value for determining the possibility of failure of the collision detection sensor according to the cumulative operating frequency of the horn detected by the horn operating frequency detection means;
Input means for inputting a resistance value between the input and output parts of the collision detection sensor;
A judgment means for comparing the diagnostic threshold set by the diagnostic threshold setting means with the resistance value inputted by the input means to judge a failure of the collision detection sensor, A failure detection device for an occupant restraint device.   2. The failure detection device for an occupant restraint device according to claim 1, wherein the horn operation frequency detection means detects the accumulated operation time of the horn as the accumulated operation frequency of the horn.   2. The failure detection device for an occupant restraint device according to claim 1, wherein the horn operation frequency detection unit detects a cumulative operation frequency of the horn as the cumulative operation frequency of the horn.   If the resistance value of the collision detection sensor exceeds the diagnostic threshold value set by the diagnostic threshold value setting means, and the determination means determines that the collision detection sensor has failed, the failure of the collision detection sensor The failure detection device for an occupant restraint device according to any one of claims 1 to 3, further comprising warning means for warning the user. The failure detection device for an occupant restraint device according to any one of claims 1 to 3, wherein the collision detection sensor and the horn are attached to a radiator support member.

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