Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-01-12
2001-03-20
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Attachment
C180S274000, C701S045000, C307S010100
Reexamination Certificate
active
06203060
ABSTRACT:
TECHNICAL ART
The instant invention generally relates to vehicle crash discrimination systems, and more particularly to a system suitable for reliably detecting impacts to the side of a vehicle.
BACKGROUND OF THE INVENTION
Generally speaking, there are known vehicle crash detection systems which attempt to detect side impacts using accelerometers mounted on the B-pillar, the rocker panel, the reinforcing beam, or some other location on or near the door of the vehicle. Other known systems use contact switches, or sense pressure changes within the door. Some distributed sensing systems have also been proposed.
These systems have not proven entirely satisfactory. More specifically, signals received by accelerometers and contact switches vary greatly depending on the location, magnitude and direction of impact. These arrangements only provide localized acceleration and velocity information, which does not necessarily reflect what is happening away from their mounting point. For example, a 15 mph pole impact (a typical airbag deployment scenario) which occurs at the sensor mounting location can induce a relatively large amplitude signal which initiates a proper air bag deployment, while one that occurs a foot or two away may give sensor signals having significantly lower amplitude thereby resulting in non-deployment of the air bag. This makes it very difficult to discriminate “fire” conditions from “no fire” situations in many cases.
Distributed sensor arrangements are difficult to install and maintain. Their cost may also be excessive due to the need for increased wiring and mounting requirements.
Furthermore, most accelerometers require a power source and thus present another potential point of system failure. Yet further, post-installation calibration of such sensors must generally be done electronically. While this may insure accurate sensing of acceleration relative to the module, it can not account for changes in the module mounting support or orientation which could result from damage caused by prior “no fire” collisions.
U.S. Pat. No. 5,580,084 discloses and claims a system and method for controlling actuation of a vehicle safety device by detecting variations in the magnetic field that is influenced by a ferromagnetic element mechanically coupled to a portion of the vehicle subject to plastic strain, whereby the plastic strain creates elastic strain waves in the ferromagnetic element which causes the ferromagnetic properties thereof to be altered by the strain waves though the process of magnetostriction. U.S. Pat. No. 5,580,084 does not teach the generation of a signal from the change in reluctance of a magnetic circuit caused by the rigid body motion of the elements therein. Furthermore, the variations in the magnetic field caused by elastic strain waves in the ferromagnetic element resulting from magnetostriction provides in itself a very low amplitude signal which is relatively insignificant with respect to variations in magnetic field caused by relative motion of rigid body elements in an associated magnetic circuit resulting from macroscopic magnetic inductive effects.
SUMMARY OF THE INVENTION
The instant invention solves the above-noted problems by providing a magnetic induction sensing system which creates a magnetic path which spans across proximal portions of two proximal elements of a motor vehicle which undergo relative motion responsive to a crash, for example proximal portions of the vehicle B-pillar and the edge surface of the associated vehicle door. As a side impact crash sensor, the instant invention detects automotive collisions that occur on or near a driver side or passenger side door, and is capable of sensing crashes whether they are localized (such as pole crashes) or broad-area hits (like bumper hits) from its mounting location on the B-pillar.
When subjected to a side impact collision, the relatively rigid vehicle door beam transfers the crash signal to the edge wall of the door. The door beam acts in rotation to magnify the motion of the crash. Therefore, a measurement of acceleration at the door edge wall captures the effects of impacts to the door and is effective for controlling the actuation of an associated side impact air bag which is useful for mitigating injury to an associated occupant subjected to a side-impact crash. Magnetic induction sensors mounted on the relatively fixed structure of the car, such as the A and B-pillars, register substantial signals that correlate well with the motion of the associated proximal edge wall of the door. These signals are caused by macroscopic motions and not magnetostrictive effects.
The instant invention incorporates a plurality of coils mounted on a pillar of the car adjacent the door edge. With a single sensing coil it is difficult to resolve the exact nature and amplitude of relative motion between the edge wall and pillar during impact, in part because of variations in the edgewall/pillar spacing that can occur amongst vehicles, or within the same vehicle over time. This problem is exacerbated because of the different types of relative motions that occur during a side impact motion in the crash direction, movement of the edge wall toward or away from the A/B pillar, and twisting and rotation of the edge wall. These multiple motions and variations in distance can be resolved with multiple coils on the pillar, and by control of the variations in the magnetic field along the edge wall.
In accordance with a first aspect of the instant invention, a system for discrimination vehicle crash situations comprises at least one coil mounted to a frame member of the vehicle, a magnet mounted to a vehicle member so as to create a magnetic field detectable by the at least one coil, and a processor connected to the at least one coil, wherein the at least one coil is induced into producing an output signal in response to change in the magnetic field caused by movement of the vehicle member in relation to the frame member. The processor analyzes the at least one coil output to determine if the change in magnetic field is indicative of a vehicle crash.
In accordance with a second aspect of the instant invention, a method of discriminating a vehicle crash comprises the steps of creating a magnetic field between an exterior structural member of the vehicle and a juxtaposed vehicle frame member, and detecting changes in the magnetic field, wherein movement of the exterior structural member relative to the frame member causes corresponding changes in the magnetic field. A vehicle collision is determined based on the detected change in the magnetic field.
Accordingly, one object of the instant invention is to provide an improved vehicle crash discrimination system and method that can be mounted to a vehicle pillar and still reliably detect side impacts occurring anywhere along the outer surface of the vehicle side, such as at a door or quarter panel location.
A further object of the instant invention is to provide an improved vehicle crash discrimination system and method that discriminates vehicle crashes by sensing motion of a vehicle door edge.
A yet further object of the instant invention is to provide an improved vehicle crash discrimination system and method that detects motion of a vehicle door edge without extending any electrical wiring to the door.
A yet further object of the instant invention is to provide an improved vehicle crash discrimination system and method that detects motion of a vehicle door edge via magnetic induction.
A yet further object of the instant invention is to provide an improved vehicle crash discrimination system and method that detects motion of a vehicle door edge via magnetic induction utilizing a coil arrangement which can detect three-dimensional motion.
In accordance with these objectives, one feature of the instant invention is a magnetic circuit spanning across proximal portions of two proximal elements of the motor vehicle which undergo relative motion responsive to the crash, whereby the magnetic circuit comprises a magnet for creating a magnemotive force within the magnetic
Cech Leonard S.
Gillis Edward J.
Sewell Michael R.
Talley David B.
Dickson Paul N.
Lyon PC
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