Communications: electrical – Land vehicle alarms or indicators
Reexamination Certificate
2000-02-25
2001-07-03
Hofsass, Jeffery (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
C340S436000, C340S438000, C340S636210, C340S661000, C340S635000
Reexamination Certificate
active
06255939
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention lies in the automotive technology field. More specifically, the invention relates to a device and a method for sensing an object or a person in the interior of a vehicle.
Persons who are displaced far forward in the direction of the dashboard such as, for example, children and infants in so-called rearward facing child seats on the front-seat passenger seat are subjected to the hazard, during the operation of a motor vehicle provided with an airbag, of suffering injuries as result of the inflation impact of the airbag in the event of an accident. Modern control systems for person protection aim at switching off the airbag in such situations or inflating it with reduced momentum in order to avoid the risk of injury to a vehicle occupant. In order to determine the position of the vehicle occupant in the vehicle, use is preferably made of contactless, optical sensors.
A device for the contactless detection of an object or of a person in the interior of a vehicle is known from European patent application EP 0 669 227 A1. There, the vehicle seat is irradiated by a number of LEDs. Beams which are reflected from the seat or a person or an object on the vehicle seat are registered by a photodetector field.
Such a device for detecting objects and persons is usually arranged in the interior of the vehicle as a device which is embodied separately from the actual control device for the occupant protection means, in such a way that it is made possible either for a vehicle occupant to be detected on the vehicle seat or else for a hazard zone to be sensed in front of the folded-up airbag. In the latter case, the interior of the vehicle, or at least part of it, is preferably examined for the presence of an object or of a person. If a child's seat or part of a body of a vehicle occupant is detected in this hazard zone, the airbag is not triggered, or is only triggered in a metered fashion.
The device is operated with a power supply. In the event of an impact in which in particular the position of a vehicle occupant must be detected in order to be able to influence the unfolding of the airbag if necessary, it is then possible to interrupt the power supply to the device by way of a mechanical effect, or to adversely affect the power supply in the form of a power leakage discharge, in such a way that the supply voltage which is necessary to operate the electrical device can no longer be permanently ensured. Thus, in the event of an impact, there is the risk of the device being operationally incapable exactly during the decisive milliseconds during the impact. Even if the power supply is still intact with a reduced supply voltage, the device is no longer capable of registering the necessary data and outputting it to a control device for the occupant protection means because the device usually contains loads with a high power requirement, such as laser diodes, for example.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and device for detecting an object or a person in the interior of a vehicle, which overcome the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which, even if the power supply of a known system is adversely affected, make available sufficient data for the control device for the occupant protection means.
With the foregoing and other objects in view there is provided, in accordance with the invention, a device for determining a presence of an object in the interior of a vehicle, comprising:
a sensor for detecting an object in an interior of a vehicle;
a power supply;
a control unit connected to the sensor, the control unit being programmed to selectively operate the sensor:
in a normal operating mode, when a sufficient power supply is detected by the control unit, during which the sensor consumes a first average power; and
in an emergency operating mode, when an insufficient power supply is detected by the control unit, during which the sensor consumes a second average power less than the first average power.
In accordance with an added feature of the invention, the control unit monitors the supply voltage of the power supply.
In accordance with an additional feature of the invention, the control unit activates the emergency operating mode as soon as the supply voltage drops below a given threshold value.
In accordance with another feature of the invention, the control unit activates the normal operating mode when the supply voltage exceeds a given threshold value.
In accordance with a further feature of the invention, the sensor is designed to scan the object with a predefined scanning rate. In a preferred embodiment, the normal scanning rate is reduced during the emergency operating mode.
In accordance with again an added feature of the invention, the sensor contains a plurality of sensor elements each monitoring an associated area.
In accordance with again a further feature of the invention, only one sensor element or a reduced number of elements is operated during the emergency operating mode.
In accordance with again another feature of the invention, the sensor includes a transmitter for emitting a signal. The transmitter is operated with a given transmission power in the normal operating mode and with a reduced transmission power, in comparison with the given transmission power, in the emergency operating mode.
In accordance with a preferred embodiment, the sensor includes an optical transmitter device and an optical receiver device.
With the above and other objects in view there is also provided, in accordance with the invention, a method for sensing an object in an interior of a vehicle, which comprises:
sensing an object in an interior of a vehicle in a normal operating mode of a sensor and thereby consuming a first average power with the sensor;
monitoring a power supply of the sensor; and operating the sensor with a second average power less than the first average power if the power supply is detected to be insufficient for the normal operation.
In this respect, a control unit of the device brings about a situation which the sensor for sensing an object or a vehicle occupant is operated with just a low average power if the power supply is classified as no longer being sufficient for normal operation. In such a context, the sensor is operated in this so-called emergency operating mode with an average power which is reduced in comparison with the average power provided for the normal operating mode.
The advantage of the invention lies in the fact that the remaining power reserves are utilized economically, in which case, if appropriate, a proportion of the maximum achievable sensor information is dispensed with in favor of generating sensor data which can still at least give a rudimentary picture of the position of the vehicle occupant to the control device for the occupant protection means, on the basis of a reduced amount of available power, but for a time period of approximately 150 milliseconds.
The device, however, is preferably not necessarily designed as a separate electrical, housed apparatus. The power supply can be configured here as a supply voltage which is fed to the apparatus from the outside, in particular as a vehicle battery voltage. However, a supply voltage which is fed from the outside and is converted in the apparatus may also be defined as a power supply. Furthermore, an autonomous supply for the electrical device in the form of a battery may also be provided as the power supply. The power supply can also comprise a power storage capacitor in the electrical apparatus, which capacitor is continuously supplied with a supply voltage fed in from the outside, and assumes the function of supplying power to the device when the standard power supply from the vehicle battery is interrupted. The resource-saving mode of operation of the device according to the invention is advantageous in just such cases.
The device for sensing an object or a person can be directed as the hazard area in front of a folde
Hamperl Reinhard
Mader Gerhard
Roesl Reinhard
Roth Christoph
Stierle Thomas
Greenberg Laurence A.
Hofsass Jeffery
Lerner Herbert L.
Nguyen Hung
Siemens Aktiengesellschaft
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