Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Reexamination Certificate
2000-09-06
2002-04-02
Lefkowitz, Edward (Department: 2632)
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
C340S436000, C340S667000, C180S273000, C280S735000, C177S2100EM
Reexamination Certificate
active
06366200
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a method of determining the presence of an object and the type of object on the seat of a passenger vehicle, and a method of determining the deployment of a safety device, particularly airbag deployment.
DESCRIPTION OF THE RELATED ART
For controlling the winding of the seat belt or deployment of the airbag, it is inevitable to determine whether or not the seat of the passenger vehicle is vacant, and if not, whether the object present on the seat is a child, an adult, a child seat, or a child seat with a child sitting thereon.
Conventionally, such determination has been made by the output values from the seat weighing instrument mounted to the seat. In other words, when the weight of the seat is below the prescribed value, it is determined that the seat is vacant, and when the value is within a prescribed range, it is determined that a child is sitting or a child seat is mounted on the seat, and when the value is over a prescribed value, it is determined that an adult is sitting on the seat.
Concerning deployment control of the airbag, a no-deployment mode (mode that the airbag is not deployed in case of collision) is selected when it is determined that the seat is vacant; a no-deployment mode or low-deployment mode (mode that the airbag is deployed at a low speed or at low pressure in case of a collision) is selected when it is determined that a child or a child seat is present on the seat; the normal mode is selected when it is determined that an adult is present on the seat. Of course, this method selects the deployment mode of the airbag directly according to the output of the seat weighing instrument, without determining what type of object is on the seat.
However, a method of determining the object on the seat only by the output of the seat weighing instrument as conventionally employed may lead to an inaccurate determination. For example, when the weight of the child seat is heavy or when the child seat is strongly restrained to the seat by a seat belt and a child is sitting on the child seat, the total weight may exceed the value by which the seat is determined to have an adult on the seat. In such a case, the airbag may deploy quickly in the normal mode
With such circumstances, it is an object of the present invention to provide a method of determining the presence and the type of object on the seat accurately and a method of determining the deployment mode of the airbag accurately.
SUMMARY OF THE INVENTION
The first embodiment of the invention is a method of determining the presence and the type of object on the seat of the passenger vehicle, including determining whether the seat is vacant, and determining whether the object present on the seat is a child seat, a child, or an adult by the combination of the outputs from the seat weight sensor and a living body proximity sensor.
In this embodiment, the vacancy of the seat or the type of on-board object is determined not only by the seat weight sensor but also by a living body proximity sensor. The living body proximity sensor is affected by the electrostatic capacitance or the electric conductivity of the living body and produces output according to the extent of proximity. (Other types of living body proximity sensors can be envisioned by those of skill in this art.) Because the vacancy of the seat and the type of on-board object are determined by the combination of outputs from the two types of sensors, a more accurate determination can be performed in comparison with the conventional method.
The second embodiment of the invention is the first embodiment, characterized in that:
(a) when the seat weight is below the prescribed value w
1
, it is determined that the seat is vacant; and
(b) when the seat weight is equal to or above the prescribed value w
1
; and
(b1) when the output value of the living body proximity sensor shows that the living body is in the proximity thereof, it is determined that a child is present on the seat when the seat weight is below a prescribed value w
2
(w
1
<w
2
), and an adult is present on the seat when the seat weight is equal to w
2
or above,
(b2) when the output value of the living body proximity sensor does not show that a living body is in the proximity thereof, it is determined that a child seat is present on the seat.
In this embodiment, the output of the seat weight is examined first and then it is determined that the seat is vacant when the seat weight is below the prescribed value w
1
, and that something is on the seat when the seat weight is equal to the prescribed value w
1
or above. When the seat weight is equal to the prescribed value or above, the type of on-board object has to be determined. At first, the living body proximity sensor is utilized to determine whether a living body is indicated. A threshold value of the output of the living body proximity sensor is set and the output of the sensor is determined to be equal to, above, or below a threshold value.
When the output of the living body proximity sensor indicates that a living body is in its proximity, a human being has been determined as presently sitting directly on the seat. The next step is to determine whether an adult or child is sitting there. A child is sitting on the seat when the seat weight is below a prescribed value w
2
(w
1
<w
2
), and that an adult is sitting on the seat when the seat weight is equal to or above as the prescribed value w
2
.
When the output of the living body proximity sensor does not indicate the presence of a living body, it is determined that a human being is not sitting on the seat but that a child seat is mounted thereon (including the case where a child is sitting on the child seat).
The third embodiment of the invention is the first embodiment characterized in that:
(a) when the seat weight is below the prescribed value w
1
, it is determined that the seat is vacant; and
(b) when the seat weight is equal to or above the prescribed value w
1
; and
(b1) when the output value of the living body proximity sensor shows that the living body is in the proximity thereof, it is determined that a child is present on the seat when the seat weight is below a prescribed value w
2
(w
1
<w
2
), and an adult is present on the seat when the seat weight is w
2
or above, or
(b2) when the output value of the living body proximity sensor does not show that the living body is in the proximity thereof, it is determined that a child seat is present on the seat when the seat weight is below a prescribed value w
3
(w
1
<w
3
), and that an adult is present on the seat or the sensor is out of order when the seat weight is equal to w
3
or above.
In this embodiment, the output of the seat weight is examined first, and then it is determined that the seat is vacant when the seat weight is below the prescribed value w
1
and that something is on the seat when the seat weight is equal to or above the prescribed value w
1
. When the seat weight is equal to the prescribed value or above, the type of on-board object has to be determined. At first, a living body proximity sensor is utilized to determine whether a living body is indicated. A threshold value of the output of the living body proximity sensor is set and the output of the sensor is determined to be equal to, above, or below the threshold value.
When the output of the living body proximity sensor indicates that a living body is in its proximity, a human being has been determined as presently sitting directly on the seat. The next step is to determine whether an adult or child is sitting there. A child is sitting on the seat when the seat weight is below a prescribed value w
2
(w
1
<w
2
) and that an adult is sitting on the seat when the seat weight is equal to or above the prescribed value w
2
.
When the output of the living body proximity sensor does not indicate the presence of a living body, it is determined that a human being is not sitting on the seat but that a child seat is mounted thereon (including the case where a child is sitting on the child seat), or the sensor is
Lefkowitz Edward
Takata Corporation
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