JP2016150595A - Pedestrian collision detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pedestrian collision detection device capable of exactly detecting the occurrence of breakage with a simple constitution.SOLUTION: A tightly closed space for detection is formed in a front bumper of a vehicle. In the front bumper, a pair of pressure sensors 8R, 8L for detecting a pressure in the space for detection are provided. A diagnostic judgement unit 11d of a pedestrian protection ECU 11, when a collision pressure calculated based on pressure detection values by means of the pressure sensors 8R, 8L is larger than a predetermined diagnostic threshold, judges that a pedestrian system 1 breaks. Acceleration sensors 9R, 9L, 9C for detecting acceleration generated on the vehicle are provided on the front bumper. A diagnostic judgement inhibition unit 11e, when a vehicle acceleration calculated based on an acceleration detection value by means of acceleration sensors 9R, 9L, 9C is a predetermined acceleration threshold or less, inhibits that it is judged by the diagnostic judgement unit 11d that the pedestrian protection system 1 breaks.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pedestrian collision detection device that detects that a pedestrian has collided with a vehicle.

  The present invention relates to a collision detection device in which a chamber is provided in a bumper at a front end portion of a vehicle, a collision of a pedestrian to the bumper is detected based on a pressure in the chamber detected by a pressure sensor, and a protection device such as a cowl airbag is activated. There was a prior art (see, for example, Patent Document 1). In the collision detection device according to the related art, when the pressure change detected by the pressure sensor is equal to or greater than a predetermined threshold value, it is determined that the bumper has been damaged more than the predetermined value and the detection unit has failed. The failure of the detection unit is notified to the vehicle occupant, and the vehicle owner can repair the detection unit. Therefore, the detection unit failure causes a false detection of a pedestrian collision with the bumper. It is prevented.

JP 2010-70129 A

However, in the above-described collision detection device according to the prior art, a pressure change exceeding a threshold value may be detected not only when an object collides with a bumper of a vehicle at a high speed but also when the object collides at a low speed. That is, when the object collides with the vehicle at a low speed, the rise of the pressure in the chamber is slower than when the object collides at a high speed, but finally rises to the same extent as when the object collides at a high speed. For this reason, in a collision caused by a low-speed object, the detection unit may be erroneously detected even though the detection unit has not actually been damaged.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pedestrian collision detection device capable of accurately detecting that damage has occurred with a simple configuration.

  In order to solve the above-mentioned problem, the invention of the pedestrian collision detection device according to claim 1 is a hollow member (7) which is disposed in the front portion (2) of the vehicle (20) and has a hollow space (7a) therein. ), Pressure detection means (8R, 8L) for detecting the pressure in the hollow space, and when the pressure detection means detects that the pressure (Pg) in the hollow space has exceeded a predetermined collision threshold (Pacv) In addition, when it is detected by the collision determination means (11f) that determines that a pedestrian collision has occurred in the front part of the vehicle and the pressure detection means, the pressure in the hollow space exceeds a predetermined diagnosis threshold (Pth) A pedestrian collision detection device (1) comprising: a damage determination means (11d) for determining that a front part has been damaged due to a collision, wherein the acceleration detection means detects an acceleration (Gg) generated in the vehicle. (9R, 9L, 9C), A determination prohibiting means (11e) for prohibiting the damage determining means from determining that damage has occurred when the speed detecting means detects that the acceleration generated in the vehicle is equal to or less than a predetermined impact threshold (Gth); I have.

  According to this configuration, when the acceleration detection unit detects that the acceleration generated in the vehicle is equal to or less than the predetermined impact threshold, it is prohibited to determine that the pedestrian collision detection device is damaged by the damage determination unit. Judgment prohibition means is provided. Thereby, when a pedestrian collides with the front part of the vehicle at a low speed, even if the pressure in the hollow space may exceed the diagnosis threshold, the acceleration generated in the vehicle by the determination prohibiting means is below a predetermined impact threshold. It is detected that there is. In this case, the determination prohibiting means prohibits the damage determining means from determining that damage has occurred. For this reason, the redundancy of the damage determination of the pedestrian collision detection device is ensured, and when a pedestrian collides with the vehicle at a low speed, it is erroneously detected that the damage has occurred based on the pressure in the hollow space. Can be prevented.

The top view of the vehicle with which the pedestrian protection system by one Embodiment of this invention was attached II-II sectional view of FIG. Block diagram showing the configuration of the pedestrian protection system The figure which showed the time chart showing the relation between the pressure in the space for detection when the pedestrian collides with the front bumper at high speed and the acceleration generated in the vehicle The figure which showed the time chart showing the relation between the pressure in the space for detection when the pedestrian collides with the front bumper at low speed and the acceleration generated in the vehicle The figure which showed the time chart showing the relation between the pressure in the space for detection when a pedestrian collides with the right or left edge part of a front bumper, and the acceleration which occurs in vehicles Schematic vehicle plan view showing the case where a pedestrian collides with the left and right center of the front bumper Schematic vehicle plan view showing the case where a pedestrian collides with the left end of the front bumper The figure which showed the control flowchart of a pedestrian protection system

<Configuration of Embodiment>
A pedestrian protection system 1 (corresponding to a pedestrian collision detection device) according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2, the left-right direction corresponds to the front-rear direction of the vehicle 20, the left side of each figure corresponds to the front of the vehicle 20, and the right side corresponds to the rear. In FIG. 1, the vertical direction corresponds to the horizontal direction of the vehicle 20. In the description, the front-rear direction of the vehicle 20 is simply referred to as the front-rear direction, and the left-right direction of the vehicle 20 is simply referred to as the left-right direction.

As shown in FIG. 1, a front bumper 2 (corresponding to a front portion of the vehicle) is attached to the front end portion of the vehicle 20. The front bumper 2 extends in the left-right direction, and includes a bumper cover 3 and a bumper absorber 4. The bumper cover 3 is made of a synthetic resin material and forms a design surface in the front portion of the vehicle 20. The bumper absorber 4 is provided behind the bumper cover 3 as a shock absorber when a collision occurs in the front portion of the vehicle 2. The bumper absorber 4 is made of, for example, a foamed resin such as foamed polypropylene.
The bumper absorber 4 is attached to the front surface 5a of the bumper reinforcement 5 at the rear end surface 4a. The bumper reinforcement 5 is a strength member having a hollow interior made of a metal material such as an aluminum alloy, and extends in the left-right direction. The bumper reinforcement 5 is fixed to front ends of a pair of side members 6R and 6L extending in the front-rear direction. On the rear end surface 4a of the bumper absorber 4 described above, a tube accommodating portion 4b is formed which is a groove portion extending in the left-right direction and opened rearward. The tube housing portion 4b has a substantially rectangular cross section, and is formed over the entire length of the bumper absorber 4 in the left-right direction.

A tube 7 for detection (corresponding to a hollow member) is built in the tube housing portion 4b. The detection tube 7 is opposed to the inner peripheral surface of the tube housing portion 4b in the front and vertical directions, and the rear is opposed to the front surface 5a of the bumper reinforcement 5. The detection tube 7 is made of, for example, a synthetic rubber such as silicon rubber or ethylene propylene rubber. The detection tube 7 has an annular cross section, and a detection space 7 a (corresponding to a hollow space) extending in the left-right direction passes through the detection tube 7. Air is sealed in the detection space 7a.
A first pressure sensor 8R and a second pressure sensor 8L (each corresponding to a pressure detection means) are attached to the left and right ends of the detection tube 7 so as to face the detection space 7a. In the present embodiment, redundancy of pressure detection in the detection space 7a is ensured by providing the first pressure sensor 8R and the second pressure sensor 8L. The first pressure sensor 8R provided at the right end of the detection tube 7 and the second pressure sensor 8L attached to the left end have the same configuration, and the air in the detection space 7a is compressed. The rise in pressure due to The first pressure sensor 8R and the second pressure sensor 8L may be a semiconductor strain gauge pressure sensor, a capacitance pressure sensor, or other pressure sensors. Hereinafter, the first pressure sensor 8R and the second pressure sensor 8L are collectively referred to as pressure sensors 8R and 8L.

  Further, the right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C (acceleration detection means, end collision detection means, and impact detection means are respectively provided on the upper surface 5b of the bumper reinforcement 5 at different positions in the left-right direction. Is applicable). The right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C detect the impact applied to the vehicle 20 at the time of collision by detecting the acceleration generated in the front-rear direction. In the present embodiment, redundancy of acceleration detection generated in the vehicle 20 is ensured by providing the right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C.

As shown in FIG. 1, the right acceleration sensor 9 </ b> R is attached to the right end portion of the bumper reinforcement 5 at the front portion of the vehicle 20. The left acceleration sensor 9L is attached to the left end portion of the bumper reinforcement 5 at the front portion of the vehicle 20. Further, the center acceleration sensor 9 </ b> C is attached to the left and right center portion of the bumper reinforcement 5 at the front portion of the vehicle 20. The right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C may be attached to members other than the bumper reinforcement 5 in the vehicle 20. The right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C may be capacitive acceleration sensors, piezoresistive acceleration sensors, or heat detection type acceleration sensors. Hereinafter, the right acceleration sensor 9R, the left acceleration sensor 9L, and the center acceleration sensor 9C are collectively referred to as acceleration sensors 9R, 9L, and 9C.
The vehicle speed sensor 10 is attached to a wheel or transmission (not shown) of the vehicle 20 and detects the traveling speed of the vehicle 20 (hereinafter referred to as a vehicle speed detection value Vs).

In the vehicle 20, a pedestrian protection ECU 11 is mounted on a floor tunnel on the front side of the driver's seat (not shown). The pedestrian protection ECU 11 is a control device formed by an input / output device (not shown), a CPU, a RAM, and the like. Details of the pedestrian protection ECU 11 will be described later.
When the pedestrian collides with the front bumper 2, the cowl airbag device 12 deploys the bag from the engine hood 20a shown in FIG. 1 to the lower portion of the front window 20b, and protects the collided pedestrian.
The pop-up hood 13 raises the rear end of the engine hood 20a when a pedestrian collides with the front bumper 2. Thereby, the pop-up hood 13 serves as a buffer member, prevents the pedestrian from colliding with a rigid member such as an engine, and protects the colliding pedestrian. Hereinafter, the cowl airbag device 12 and the pop-up hood 13 may be collectively referred to as pedestrian protection devices 12 and 13.
The warning lamp 14 is provided in an instrument panel (not shown) of the vehicle 20. The warning lamp 14 is lit when it is determined that the pedestrian protection system 1 is damaged due to a pedestrian collision, and notifies the occupant that the pedestrian protection system 1 has been damaged.

As shown in FIG. 3, the pedestrian protection ECU 11 includes the pressure sensors 8R and 8L, the acceleration sensors 9R, 9L and 9C, the vehicle speed sensor 10, the cowl airbag device 12, the pop-up hood 13 and the warning lamp 14. Connected by communication line.
The pedestrian protection ECU 11 includes an input unit 11a, a collision position determination unit 11b, a threshold change unit 11c, a diagnosis determination unit 11d, a diagnosis determination prohibition unit 11e, a collision determination unit 11f, and a protection device drive unit 11g.

Detection signals from the pressure sensors 8R and 8L, the acceleration sensors 9R, 9L, and 9C and the vehicle speed sensor 10 are input to the input unit 11a.
The collision position determination unit 11b (corresponding to the end collision detection unit) allows the pedestrian to move to the left or right end of the front bumper 2 based on the acceleration detection values detected by the acceleration sensors 9R, 9L, and 9C. Detect a collision. The acceleration detection value is a generic name including a right acceleration value Gr, a left acceleration value Gl, and a center acceleration value Gc described later. The right acceleration value Gr and the left acceleration value Gl correspond to the detection values by the impact detection means attached to the left and right ends, and the center acceleration value Gc is the detection value by the impact detection means attached to the left and right center portions. Applicable.
Specifically, the right acceleration value Gr detected by the right acceleration sensor 9R is larger than the center acceleration value Gc detected by the center acceleration sensor 9C, or the left acceleration value Gl detected by the left acceleration sensor 9L is When the acceleration value is larger than the center acceleration value Gc, it is detected that the pedestrian has collided with one of the left and right ends of the front bumper 2. In other cases, it is not detected that the pedestrian collides with either of the left and right ends of the front bumper 2.

The threshold value changing unit 11c (corresponding to the threshold value changing means) causes the pedestrian to collide with either the left or right end of the front bumper 2 by the collision position determination unit 11b (the pedestrian collides with the left and right end parts in the front part of the vehicle) Is detected), the diagnosis threshold value Pth is decreased. The diagnosis threshold Pth is a predetermined threshold provided to determine that the pedestrian protection system 1 is damaged due to a pedestrian collision. The diagnosis threshold value Pth is a threshold value for the collision pressure Pg (corresponding to the pressure in the hollow space) calculated based on the pressure detection values by the pressure sensors 8R and 8L. The collision pressure Pg may be obtained by averaging the pressure detection values of the first pressure sensor 8R and the second pressure sensor 8L, or may be a larger value of the two pressure detection values. The damage of the pedestrian protection system 1 described above mainly refers to the damage of the front bumper 2 including the pressure sensors 8R, 8L and the acceleration sensors 9R, 9L, 9C. Determining that the front bumper 2 of the pedestrian protection system 1 is damaged is hereinafter referred to as “determining as a diagnosis”.
The diagnosis threshold value Pth is normally set to the high threshold value PvH. The diagnosis threshold value Pth is set to a low threshold value PvL (PvH> PvL) smaller than the high threshold value PvH when the collision position determination unit 11b detects that the pedestrian has collided with either of the left and right ends of the front bumper 2. Be changed.

The diagnosis determination unit 11d (corresponding to the damage determination means) determines whether or not the collision pressure Pg is larger than the diagnosis threshold Pth described above. If the collision pressure Pg is larger than the diagnosis threshold value Pth, the diagnosis determination unit 11d determines that the diagnosis is for the pedestrian protection system 1, and turns on the warning lamp 14.
The diagnosis determination prohibiting unit 11e (corresponding to the determination prohibiting means) is configured such that the vehicle acceleration Gg (corresponding to the acceleration generated in the vehicle) calculated based on the acceleration detection values by the acceleration sensors 9R, 9L, 9C is a predetermined acceleration. It is determined whether or not it is larger than a threshold Gth (corresponding to an impact threshold). The vehicle acceleration Gg may be obtained by averaging the acceleration detection values of the acceleration sensors 9R, 9L, and 9C, or may be the largest value among the three acceleration detection values. When the diagnosis determination prohibiting unit 11e detects that the vehicle acceleration Gg is equal to or less than the acceleration threshold value Gth (corresponding to the impact threshold value or less), the diagnosis determination prohibiting unit 11e prohibits the diagnosis determination unit 11d from determining that the diagnosis is a diagnosis. As described above, the acceleration sensors 9R, 9L, and 9C include the impact detection means for detecting that the pedestrian has collided with the left or right end of the front bumper 2, and the diagnosis determination unit 11d is the diagnosis. It also serves as acceleration detection means for prohibiting determination.

The collision determination unit 11f (corresponding to the collision determination unit) determines whether or not the vehicle speed detection value Vs detected by the vehicle speed sensor 10 is equal to or higher than a predetermined minimum vehicle speed Vmin and equal to or lower than the maximum vehicle speed Vmax. ing. The collision determination unit 11f determines whether or not the collision pressure Pg is greater than a predetermined collision threshold Pacv different from the diagnosis threshold Pth. The collision determination unit 11f allows the pedestrian to move to the front bumper 2 when the vehicle speed detection value Vs is not less than the minimum vehicle speed Vmin and not more than the maximum vehicle speed Vmax, and the collision pressure Pg is greater than a predetermined collision threshold value Pacv. It is determined that there is a collision (corresponding to a pedestrian collision occurring in the front part of the vehicle). In the present embodiment, the collision threshold value Pacv is set to be larger than the diagnosis threshold value Pth (Pacv> Pth).
The protection device drive unit 11g operates the cowl airbag device 12 or the pop-up hood 13 when the collision determination unit 11f determines that the pedestrian has collided with the front bumper 2.

Hereinafter, based on FIG. 4A thru | or FIG. 5B, the diagnostic determination method of the pedestrian protection system 1 by this embodiment is explained in full detail. 4A to 4C show diagrams of a collision pressure Pg and a vehicle acceleration Gg that are generated when a pedestrian collides with the front bumper 2. 4A and 4B are diagrams showing a case where a pedestrian collides with the left and right center part of the front bumper 2 (shown in FIG. 5A), and FIG. 4C shows that a pedestrian collides with either the left or right end part of the front bumper 2. FIG. 5 shows respective diagrams in the case of (when only colliding with the left end portion in FIG. 5B).
It has been empirically known that when a pedestrian collides with either the left or right end portion of the front bumper 2, the collision pressure Pg is less likely to increase than when the pedestrian collides with the left and right center portion of the front bumper 2. Therefore, compared with FIG. 4A and FIG. 4B, the peak value of the collision pressure Pg shown in FIG. 4C is a small value. Therefore, in FIG. 4A and FIG. 4B, the diagnosis threshold value Pth is set to the high threshold value PvH, and in FIG. 4C, the diagnosis threshold value Pth is set to the low threshold value PvL. On the other hand, the vehicle acceleration Gg shown in FIG. 4C rises to the same extent as that shown in FIG. 4A.
4A shows characteristics when a pedestrian collides with the vehicle 20 at a high speed, and FIG. 4B shows characteristics when a pedestrian collides with the vehicle 20 at a low speed. The collision pressure Pg shown in FIG. 4B rises later than that in FIG. 4, but rises to the same extent. Further, the vehicle acceleration Gg shown in FIG. 4B is much smaller than that in FIG. 4A.

As shown in FIG. 4A, at the same time, when there is a moment (indicated by td1 and td2) in which the collision pressure Pg is larger than the high threshold value PvH and the vehicle acceleration Gg is larger than the acceleration threshold value Gth, diagnosis determination is performed at that time. The part 11d determines that it is a diagnosis of the pedestrian protection system 1.
On the other hand, as shown in FIG. 4B, even when the collision pressure Pg is larger than the high threshold value PvH, when the vehicle acceleration Gg is equal to or less than the acceleration threshold value Gth, the diagnosis determination prohibiting unit 11e It is prohibited to be determined as a diagnosis of the protection system 1.
Further, as shown in FIG. 4C, at the same time, when there is a moment (indicated by td3 and td4) where the collision pressure Pg is larger than the low threshold value PvL and the vehicle acceleration Gg is larger than the acceleration threshold value Gth. The diagnosis determination unit 11d determines the diagnosis of the pedestrian protection system 1.

  Hereinafter, based on FIG. 6, the control method of the pedestrian protection system 1 by pedestrian protection ECU11 is demonstrated. In the flowchart shown in FIG. 6, steps S104 to S108 indicate a diagnosis determination routine. Steps S109 to S111 show a collision detection routine. The diagnosis determination routine and the collision detection routine are always executed in parallel. First, the vehicle speed detection value Vs of the vehicle 20 is input from the vehicle speed sensor 10 to the input unit 11a (step S101). Next, acceleration detection values are input from the acceleration sensors 9R, 9L, and 9C to the input unit 11a (step S102). Further, a pressure detection value is input from the pressure sensors 8R and 8L to the input unit 11a (step S103).

  The collision position determination unit 11b determines whether the right acceleration value Gr is larger than the center acceleration value Gc or the left acceleration value Gl is larger than the center acceleration value Gc (step S104). When the right acceleration value Gr is greater than the center acceleration value Gc or the left acceleration value Gl is greater than the center acceleration value Gc, the collision position determination unit 11b It is determined that there is a collision. In this case, the threshold value changing unit 11c changes the diagnosis threshold value Pth from the high threshold value PvH to the low threshold value PvL (step S105). When the right acceleration value Gr is equal to or less than the center acceleration value Gc and the left acceleration value Gl is equal to or less than the center acceleration value Gc, the diagnosis threshold value Pth is not changed and remains the high threshold value PvH that is the initial value.

  Thereafter, the diagnosis determination unit 11d determines whether or not the collision pressure Pg is larger than the diagnosis threshold Pth (high threshold PvH or low threshold PvL) (step S106). When the collision pressure Pg is greater than the diagnosis threshold value Pth, the diagnosis determination prohibiting unit 11e determines whether or not the vehicle acceleration Gg is greater than the acceleration threshold value Gth (step S107). When the vehicle acceleration Gg is larger than the acceleration threshold Gth, the diagnosis determination unit 11d determines that the diagnosis is for the pedestrian protection system 1 (step S108). When it is determined that the diagnosis is for the pedestrian protection system 1, the warning lamp 14 is turned on to notify the occupant that the pedestrian protection system 1 has been damaged, and then the diagnosis determination routine is terminated. Moreover, when it determines with the diagnosis of the pedestrian protection system 1, you may make it cancel | release the subsequent collision determination and the action | operation of the pedestrian protection apparatuses 12 and 13. FIG. When the collision pressure Pg is equal to or less than the diagnosis threshold value Pth, the diagnosis determination unit 11d ends the diagnosis determination routine without determining the diagnosis of the pedestrian protection system 1 (step S106). Even when the collision pressure Pg is larger than the diagnosis threshold value Pth, when the vehicle acceleration Gg is less than or equal to the acceleration threshold value Gth, the diagnosis determination prohibiting unit 11e determines that the diagnosis determination unit 11d is a diagnosis of the pedestrian protection system 1. This is prohibited and the diagnosis determination routine is terminated (step S107).

  On the other hand, the collision determination unit 11f determines whether or not the input vehicle speed detection value Vs is not less than the minimum vehicle speed Vmin and not more than the maximum vehicle speed Vmax (step S109). If the vehicle speed detection value Vs is less than the minimum vehicle speed Vmin or greater than the maximum vehicle speed Vmax, the collision detection routine ends. When the vehicle speed detection value Vs is not less than the minimum vehicle speed Vmin and not more than the maximum vehicle speed Vmax, the collision determination unit 11f determines whether or not the collision pressure Pg is larger than the collision threshold value Pacv (step S110). When the collision pressure Pg is larger than the collision threshold Pacv, it is determined that a pedestrian has collided with the front bumper 2. If it is determined that a pedestrian has collided with the front bumper 2, the collision detection routine ends after the pedestrian protection devices 12 and 13 are activated by the protection device driving unit 11g (step S111). When the collision pressure Pg is equal to or lower than the collision threshold value Pacv, the pedestrian protection devices 12 and 13 are not operated and the collision detection routine ends.

<Effects of Embodiment>
According to the present embodiment, when the acceleration sensors 9R, 9L, and 9C detect that the vehicle acceleration Gg is equal to or less than the acceleration threshold value Gth, the diagnosis determination unit 11d determines that the pedestrian protection system 1 has been damaged. A diagnosis determination prohibiting unit 11e that prohibits this is provided. Thereby, when a pedestrian collides with the front bumper 2 of the vehicle 20 at a low speed, even if the collision pressure Pg in the detection space 7a may exceed the diagnosis threshold value Pth, the vehicle acceleration Gg is equal to or less than the acceleration threshold value Gth. It is detected that there is. In this case, the diagnosis determination prohibition unit 11e prohibits the diagnosis determination unit 11d from determining that damage has occurred. For this reason, it is ensured that the diagnosis determination redundancy is ensured, and when the pedestrian collides with the front bumper 2 at a low speed, it is erroneously determined that the pedestrian protection system 1 is damaged based on the pressure in the detection space 7a. Can be prevented.

  The collision threshold value Pacv for detecting a pedestrian collision with the front bumper 2 is set to be larger than the diagnosis threshold value Pth. Thereby, prior to detection of a pedestrian collision, it is possible to detect whether or not the pedestrian protection system 1 is damaged, and the pedestrian protection system 1 can always be kept in a normal state.

  The pedestrian protection system 1 includes acceleration sensors 9R, 9L, 9C and a collision position determination unit 11b that detect that a pedestrian has collided with one of the left and right ends of the front bumper 2. When the collision position determination unit 11b detects that the pedestrian has collided with either the left or right end of the front bumper 2, the pedestrian protection system 1 reduces the diagnosis threshold Pth from the high threshold PvH. A threshold value changing unit 11c for changing to the threshold value PvL is provided. As a result, even when the pedestrian collides with one of the left and right ends of the front bumper 2 and the pedestrian protection system 1 is damaged, the diagnosing threshold Pth is increased even when the collision pressure Pg is difficult to increase. Can be determined as a diagnosis of the pedestrian protection system 1.

  As means for detecting a pedestrian collision site, the front bumper 2 includes a plurality of acceleration sensors 9R, 9L, and 9C that are arranged at different positions in the left-right direction and detect acceleration generated in the vehicle 20, respectively. When at least one of the right acceleration value Gr by the right acceleration sensor 9R and the left acceleration value Gl by the left acceleration sensor 9L is larger than the center acceleration value Gc by the center acceleration sensor 9C, the pedestrian is left and right in the front bumper 2 It has detected that it collided with either end. Thereby, it is possible to detect that a pedestrian has collided with one of the left and right ends of the front bumper 2 with a simple configuration, and the pedestrian protection system 1 can be reduced in size and weight.

  The acceleration sensors 9R, 9L, and 9C that detect that a pedestrian has collided with one of the left and right ends of the front bumper 2 are configured to prohibit the vehicle 20 from being judged by the diagnosis judging unit 11d as being damaged. It also serves as an acceleration detection means for detecting the acceleration generated in. Thereby, the collision part and collision acceleration of the pedestrian in the front bumper 2 can be detected with few components, and the small and low-cost pedestrian protection system 1 can be obtained.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
The magnitude relationship between the collision threshold Pacv and the diagnosis threshold Pth can be freely set according to the specifications of the vehicle 20. Therefore, the diagnosis threshold value Pth may be set larger than the collision threshold value Pacv, or the collision threshold value Pacv and the diagnosis threshold value Pth may be set to the same value.
When a pedestrian collides with the vehicle 20, the effective mass M of the colliding pedestrian is calculated based on the formula: M = (∫Pg (t) dt) / Vs, and based on the effective mass M, You may make it detect that the pedestrian collided. In the above equation, Pg (t) represents the collision pressure Pg at a predetermined time.
Further, the number of pressure sensors 8R and 8L for detecting the pressure in the detection space 7a is not necessarily two, and only one may be provided in the front portion of the vehicle 20, or three or more may be attached. It may be.
Further, the number of acceleration sensors 9R, 9L, 9C for detecting a pedestrian collision site on the front bumper 2 is not necessarily three, and four or more acceleration sensors may be attached to the front portion of the vehicle 20. Good.
Further, in order to detect a pedestrian collision site on the front bumper 2, a plurality of pressure sensors provided at different positions in the left-right direction in the front portion of the vehicle 20 instead of the acceleration sensors 9R, 9L, 9C A load sensor may be used.
Further, the mounting position and mounting method of the detection tube 7 in the bumper absorber 4 can be changed according to the specifications of the vehicle 20.

  In the drawings, 1 is a pedestrian protection system (pedestrian collision detection device), 2 is a front bumper (front part of the vehicle), 7 is a detection tube (hollow member), 7a is a detection space (hollow space), and 8R is the first. 1 pressure sensor (pressure detection means), 8L a second pressure sensor (pressure detection means), 9R a right acceleration sensor (acceleration detection means, end collision detection means, impact detection means attached to left and right ends), 9L Is a left acceleration sensor (acceleration detection means, end collision detection means, impact detection means attached to the left and right ends), and 9C is a center acceleration sensor (acceleration detection means, end collision detection means, left and right center part). (Impact detection means), 11b is a collision position determination section (end collision detection means), 11c is a threshold change section (threshold change means), 11d is a diagnosis determination section (breakage determination means), and 11e is a diagnosis determination. Stop portion (determination prohibition means), 11f is a collision determination portion (collision determination means), 20 is a vehicle, Gg is a vehicle acceleration (acceleration generated in the vehicle), Gc is a center acceleration value (impact detection attached to the left and right central portions) Gl is the left acceleration value (detected value by the impact detecting means attached to the left and right ends), Gr is the right acceleration value (detected value by the impact detecting means attached to the left and right ends), and Gth is Acceleration threshold (impact threshold), Pacv is a collision threshold, Pg is a collision pressure (pressure in a hollow space), and Pth is a diagnosis threshold.

Claims (5)

A hollow member (7) disposed in the front portion (2) of the vehicle (20) and having a hollow space (7a) therein;
Pressure detecting means (8R, 8L) for detecting the pressure in the hollow space;
Collision determination for determining that a pedestrian collision has occurred in the front portion of the vehicle when the pressure detection means detects that the pressure (Pg) in the hollow space exceeds a predetermined collision threshold (Pacv) Means (11f);
A damage determination means (11d) for determining that the front portion has been damaged by a collision when the pressure detection means detects that the pressure in the hollow space exceeds a predetermined diagnosis threshold (Pth);
A pedestrian collision detection device (1) comprising:
Acceleration detecting means (9R, 9L, 9C) for detecting acceleration (Gg) generated in the vehicle;
Determination prohibiting means (11e) for prohibiting the damage determining means from determining that damage has occurred when the acceleration detecting means detects that the acceleration generated in the vehicle is equal to or less than a predetermined impact threshold (Gth). When,
A pedestrian collision detection device.   The pedestrian collision detection device according to claim 1, wherein the collision threshold is larger than the diagnosis threshold. End collision detection means (9R, 9L, 9C, 11b) for detecting that a pedestrian collision has occurred at the left and right ends of the front portion of the vehicle;
A threshold value changing means (11c) for decreasing the diagnosis threshold value when it is detected by the end collision detection means that a pedestrian collision has occurred at the left and right ends of the front part of the vehicle;
The pedestrian collision detection device according to claim 1 or 2, further comprising: The end collision detection means is
The vehicle includes a plurality of impact detection means (9R, 9L, 9C) that are disposed at different positions in the left-right direction of the vehicle at the front portion of the vehicle and detect impacts generated on the vehicle,
The detection values (Gr, Gl) detected by the impact detection means (9R, 9L) attached to the left and right ends of the front part of the vehicle are the impact detection means attached to the left and right center parts of the front part of the vehicle ( The pedestrian collision detection device according to claim 3, wherein when the detected value (Gc) is greater than 9C), it detects that a pedestrian collision has occurred at the left and right ends of the front portion of the vehicle.   The pedestrian collision detection device according to claim 4, wherein the impact detection unit also serves as the acceleration detection unit.

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