JP2007218646A - Occupant detector for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an occupant detector for a vehicle capable of preventing incorrect determination by taking into consideration the influence of rapid changes in the temperature caused by opening or closing of a door. <P>SOLUTION: The occupant detector, equipped with a load sensor 3 for detecting a load acting on a seat 4 of the vehicle, and an ECU 2 for occupant detection to determine at least whether there is any occupant by operating a detection result by the load sensor 3, is provided with a door switch 9 for detecting the opening and closing of each door of the vehicle. Processings in steps S3, S4 performed in the occupant-detecting ECU 2 for prohibiting reference value correction for the load sensor 3 and occupant determination from being performed; while the door is open or during a predetermined time duration (t seconds) after the door has closed, are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a vehicle occupant detection device that detects whether an occupant is seated on a vehicle seat.

Conventionally, even if the reference load value is deviated due to the vehicle body being distorted due to a minor collision or the like, it is impossible to properly determine the presence or absence of an occupant. It is detected that the change from the door closed state to the door open state is detected, the subsequent decrease in weight is detected, and the weight value after the decrease is stored as a value at the time of empty seat (for example, Patent Document 1). reference.).
Japanese Patent No. 3578112 (page 1-10, all figures)

  However, the conventional vehicle occupant detection device does not consider whether or not it is affected by a sudden change in temperature due to the opening and closing of the door. There was a possibility.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a vehicle occupant detection device capable of preventing erroneous determination in consideration of the influence of a sudden temperature change accompanying opening and closing of a door. It is to provide.

  In order to achieve the above object, in the present invention, a vehicle occupant comprising: a load sensor that detects a load applied to a vehicle seat; and a determination unit that calculates a detection result of the load sensor and determines at least the presence or absence of an occupant. In the detection device, the door opening / closing detection means for detecting the opening / closing of the vehicle door, and the reference value correction of the load sensor is prohibited within a predetermined time after the door is opened or closed, thereby improving the detection accuracy. And means for prohibiting occupant determination and preventing erroneous determination within a predetermined time after the door is open or closed.

  Therefore, in the present invention, when the temperature difference between the inside and outside of the vehicle is large, opening the door causes the temperature to fluctuate and the sensor is affected by this, and it does not operate normally for a certain period of time. When it is detected and the door is open, correction of zero point (correction due to deterioration) and occupant determination are not performed, so that erroneous detection can be prevented.

  In addition, it will be affected by the temperature until the temperature inside the vehicle (temperature near the sensor) is stabilized to some extent, but for t seconds (time until stabilization) after the door is closed, 0 point correction and occupant determination are performed. Since it is not performed (previous information is retained), erroneous determination can be prevented.

  Hereinafter, an embodiment for realizing the vehicle occupant detection device of the present invention will be described based on Example 1. FIG.

First, the configuration will be described.
FIG. 1 is a diagram illustrating a configuration example of an airbag system using the vehicle occupant detection device according to the first embodiment. FIG. 2 is a block diagram of an airbag system using the vehicle occupant detection device of the first embodiment.
The airbag system according to the first embodiment mainly includes an airbag ECU 1, an occupant detection ECU 2, load sensors 3 a to 3 d, an occupant state display lamp 6, an airbag 7, and a warning lamp 8.

The airbag ECU 1 has a built-in CPU 11 and, based on the occupant information obtained from the occupant detection ECU 2, the airbag ECU 1 does not deploy when there is no occupant, deploys when an adult, and does not deploy when a child seat is installed. Perform deployment control.
The occupant detection ECU 2 incorporates a CPU 21, processes the output from the load sensor 3, determines the presence of the occupant, whether the occupant is an adult or a child, and outputs the determination result.
The load sensors 3a to 3d output detection voltages according to the load at four different positions on the seat.
The load sensors 3a to 3d include temperature sensors 3e to 3h inside.

The occupant state display lamp 6 displays, for example, detection results of occupant states such as no occupant, an adult, and a child seat.
The airbag 7 is deployed to protect the occupant during a vehicle collision and exhibits a buffer function. Further, the expansion stage can be changed to at least two stages by the control.
The warning lamp 8 is an indicator lamp for displaying a warning when a failure in the airbag system is detected.
The door switch 9 detects the open / closed state of the vehicle door and outputs information indicating the state to the occupant detection ECU 2.

FIG. 3 is an explanatory diagram illustrating a mounting structure of load sensors 3a to 3d of the vehicle occupant detection device according to the first embodiment. 3A is a plan view, FIG. 3B is a side view, and FIG. 3C is a front view.
The four load sensors 3a to 3d are respectively provided at the right front part, the rear part, the left front part, and the rear part that support the load on the seat rail 5 of the seat 4 of the vehicle. Thereby, the load to each part is detected.

Next, the operation will be described.
[About airbag system]
Here, the airbag system of Example 1 will be described.
In the airbag system of the first embodiment, the airbag 7 changes the magnitude of deployment at the time of a vehicle collision into at least two stages.
In other words, the vehicle occupant detection device detects three states of no occupant, a child's seat, and an adult's seat, and in accordance with this state, the airbag 7 is not deployed when no occupant is present. In this case, the vehicle is controlled to expand in a small manner, and in the case where the occupant is an adult, the vehicle is expanded greatly.

Thereby, the cushioning mechanism of the airbag 7 can be exhibited appropriately according to the state of the occupant.
In other words, in the vehicle occupant detection device, more accurate detection of the occupant is required, and for this reason, it is difficult to correct the zero point when there is no occupant and to grasp the state so that the detection is not performed in an unstable state. It becomes.
These are solved by the vehicle occupant detection device of the first embodiment.

[Crew detection and temperature]
Here, occupant detection and temperature in the vehicle occupant detection device incorporated in the airbag system of the first embodiment will be described.
In the vehicle occupant detection device, the load sensor has an ASIC (Application Specific Integrated Circuit) inside, senses the temperature inside the ASIC, and performs temperature correction. However, when a sudden change in temperature occurs, the outside of the sensor is immediately affected. However, since it takes time until the temperature is transmitted to the inside, there is a temperature difference between the outside and the inside. Thermal distortion occurs due to the temperature difference, and an output appears as if a load was input. If the zero point correction or occupant determination is performed using the data, there is a possibility of erroneous detection, which is a problem.
This problem is solved in the first embodiment.

[Control for door opening and closing]
FIG. 4 is a flowchart showing a flow of control for door opening / closing executed by the occupant detection ECU 2 of the vehicle occupant detection device according to the first embodiment. Each step will be described below.

  In step S1, it is determined from the detection result by the door switch 9 whether or not the door is open. If the door is open, the process proceeds to step S3. If the door is closed, the process proceeds to step S2.

In step S2, it is determined whether it is within t seconds after the door is closed. If it is within t seconds, the process proceeds to step S3, and if it is over t seconds, the process is terminated.
Note that t seconds is a predetermined time.

  In step S3, it is determined that there is a possibility of being affected by a sudden temperature change.

  In step S4, the start of the zero point correction or the occupant determination is performed.

[Action that prohibits correction and judgment against temperature changes due to door opening and closing]
FIG. 5 is a graph showing sensor output when the temperature suddenly changes in the warm direction in the vehicle occupant detection device of the first embodiment. FIG. 6 is a graph showing the sensor output when the temperature suddenly changes in the cooling direction in the vehicle occupant detection device of the first embodiment.

  Opening the door when the temperature difference between the inside and outside of the car is severe will cause the temperature to fluctuate and the sensor will be affected, and it will not operate normally for a certain period of time, but the door is opened and closed, and the door is open Sometimes no correction (correction due to deterioration) or occupant determination is performed, so that no false detection is made.

  In addition, although it is affected by the temperature until the temperature inside the vehicle (temperature near the sensor) is stabilized to some extent, the correction of the zero point and the determination of the occupant are performed for t seconds (time until stabilization) after the door is closed. Since there is no (previous information is retained), no erroneous determination is made.

  Referring to FIGS. 5 and 6, in FIGS. 5 and 6, the sensor output value is affected within about 200 seconds in the initial stage, but in Example 1, both are within t seconds. Thus, this rapidly changing value is not used. Therefore, it is possible to avoid the influence of such a temperature change.

[Action on airbag system]
In the vehicle occupant detection device according to the first embodiment, 0 point correction and occupant detection within t seconds from the door open or door close are prohibited according to the open / close state of the vehicle door by the door switch 9, and erroneous determination is prevented. .
As a result, the vehicle occupant detection device can perform more accurate occupant detection, and the airbag system can further reduce the possibility of malfunction and perform an appropriate operation.

Next, the effect will be described. The vehicle occupant detection device according to the first embodiment has the following effects.
(1) In a vehicle occupant detection device including a load sensor 3 that detects a load applied to a vehicle seat 4 and an occupant detection ECU 2 that calculates a detection result of the load sensor 3 and determines at least the presence or absence of an occupant. A door switch 9 that detects the opening and closing of the door, and an occupant detection ECU 2 that prohibits reference value correction and occupant determination of the load sensor 3 within a predetermined time (t seconds) after the door is opened or closed. Since the steps S3 and S4 are performed, opening the door when the temperature difference between the inside and outside of the vehicle is severe causes the temperature to fluctuate and the sensor is affected, and the door does not operate normally for a certain period of time. When the opening / closing of the vehicle is detected and the door is open, zero point correction (correction due to deterioration) and occupant determination are not performed, thereby preventing erroneous detection.

  In addition, it will be affected by the temperature until the temperature inside the vehicle (temperature near the sensor) is stabilized to some extent, but for t seconds (time until stabilization) after the door is closed, 0 point correction and occupant determination are performed. Since it is not performed (previous information is retained), erroneous determination can be prevented.

  As mentioned above, although the vehicle occupant detection device of the present invention has been described based on the first embodiment, the specific configuration is not limited to these embodiments, and the invention according to each claim of the claims. Design changes and additions are permitted without departing from the gist of the present invention.

The door switch that detects the opening and closing of the door may be anywhere on the driver's seat side, passenger seat side, and rear seat.
The zero-point correction process and occupant detection that are prohibited for t seconds after the door is opened and closed may be another process that is equivalent to or equivalent to this.
The load sensor includes one using a strain gauge or a fluid, and any sensor may be used as long as it can accurately detect the occupant's load.

It is a figure which shows the structural example of the airbag system using the passenger detection apparatus for vehicles of Example 1. FIG. 1 is a block diagram of an airbag system using the vehicle occupant detection device of Embodiment 1. FIG. It is explanatory drawing which shows the attachment structure of the load sensors 3a-3d of the vehicle occupant detection apparatus of Example 1. FIG. 4 is a flowchart showing a flow of control for door opening and closing executed by an occupant detection ECU 2 of the vehicle occupant detection device of the first embodiment. In the vehicle occupant detection device of Example 1, it is a graph showing the sensor output when the temperature suddenly changes in a warm direction. In the vehicle occupant detection device of the first embodiment, it is a graph showing the sensor output when the temperature suddenly changes in the cooling direction.

Explanation of symbols

1 Airbag ECU1
11 CPU
2 ECU2 for occupant detection
21 CPU
3 Load sensors 3a to 3d Load sensors 3e to 3h Temperature sensor 4 Seat 5 Seat rail 6 Occupant status display lamp 7 Air bag 8 Warning lamp 9 Door switch

Claims (1)

A load sensor for detecting a load applied to a vehicle seat;
A determination means for calculating a detection result of the load sensor and determining at least the presence or absence of an occupant;
In a vehicle occupant detection device comprising:
Door opening / closing detection means for detecting opening / closing of a vehicle door;
Within a predetermined time after the door is open or closed, means for prohibiting reference value correction of the load sensor and improving detection accuracy;
Means for prohibiting occupant determination and preventing erroneous determination within a predetermined time after the door is open or closed;
An occupant detection device for a vehicle, comprising:

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