Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/01516—Passenger detection systems using force or pressure sensing means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/0153—Passenger detection systems using field detection presence sensors
  • B60R21/01532—Passenger detection systems using field detection presence sensors using electric or capacitive field sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/0153—Passenger detection systems using field detection presence sensors
  • B60R21/0154—Passenger detection systems using field detection presence sensors in combination with seat heating
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01G—WEIGHING
  • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
  • G01G19/40—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight
  • G01G19/413—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means
  • G01G19/414—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only
  • G01G19/4142—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only for controlling activation of safety devices, e.g. airbag systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/01544—Passenger detection systems detecting seat belt parameters, e.g. length, tension or height-adjustment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/02—Occupant safety arrangements or fittings, e.g. crash pads
  • B60R21/16—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags
  • B60R21/20—Arrangements for storing inflatable members in their non-use or deflated condition; Arrangement or mounting of air bag modules or components
  • B60R21/215—Arrangements for storing inflatable members in their non-use or deflated condition; Arrangement or mounting of air bag modules or components characterised by the covers for the inflatable member

Definitions

• the instant invention relates generally to automotive passenger restraint systems and more specifically to a system and method for controlling the inflation of an air bag in occupant seating situations where the passenger is at risk of injury from deployment thereof .
• the present invention comprises a seat weight sensor, a seat belt tension sensor, and a capacitive sensor located in the instrument panel or dashboard near the air bag inflator door for sensing the proximity of a human to the air bag deployment danger zone.
• Seat weight sensors are being developed to determine when the passenger seat occupant is sufficiently small to require the disablement of an air bag inflator. Such sensors should ideally be capable of determining when the child is in a rear facing infant seat, a forward facing child seat or a booster seat. Occupant weight measurement in child seat occupant situations is complicated by the force exerted downwardly on the seat by seat belt tension. A tightly belted child seat increases the measured weight or force exerted on the seat, possibly causing air bag deployment on children or infants.
• Detection of the presence of infant seats, children, and small adults is necessary to inhibit air bag deployment in situations where the seat occupant is at risk of injury from air bag inflation. Occupants below a threshold weight have a high risk of injury from the deployment of an air bag. Similarly, occupants who are in close proximity to the air bag inflator door at the time of deployment are also likely to be injured. Accordingly, a system for controlling air bag inflation that accurately determines both occupant size and position is advantageous.
• a capacitive or electric field sensor is provided to determine whether an occupant is proximate the air bag door at the time of air bag deployment.
• the capacitive sensor is provided with a pair of spaced conductive electrodes having a dielectric therebetween and a means for measuring capacitance. The value of capacitance of the sensor varies with the value of the dielectric material disposed between the electrodes.
• the capacitive sensor is positioned at a point relative to the air bag inflator door such that an occupant within a predetermined distance, i.e., the "danger zone" of the air bag inflator door, changes the dielectric constant of the sensor and thereby varies the capacitance thereof.
• the capacitive sensor has the ability to detect an unbelted occupant entering the danger zone of the air bag inflator door as the occupant is thrown forward from the force of severe braking.
• Prior art systems utilizing only seat weight and belt tension sensors are incapable of determining whether an occupant is out of position, thereby allowing air bag inflation even when occupants are at risk of injury.
• An airbag control processor operatively coupled to the aforementioned sensors is provided to inhibit the deployment of the air bag upon detection of the appropriate occupant situation.
• seat belt tension in excess of 1 0 lbs. is generally uncomfortable for adult occupants.
• the air bag control processor disables the output signal to the electro-explosive squibs that deploy the bag.
• the processor disables the air bag. Furthermore, the processor disables the air bag under any combination of weight and seat belt tension conditions if an occupant is detected within the danger zone of the air bag inflator door.
• the weight sensor also provides an output signal operatively coupled to the air bag control system for controlling an air bag inflator having variable inflation characteristics.
• an air bag control system for controlling an air bag inflator having variable inflation characteristics.
• one object of the instant invention is to provide an air bag suppression system that monitors and evaluates occupant weight, seat belt tension, and occupant proximity to the air bag inflator prior to deployment of the air bag. Deployment decisions based on the three aforementioned criteria provide a system that can reliably detect the presence of a passenger at risk of injury from air bag deployment.
• Yet another object of the instant invention is to provide an air bag suppression system that detects the presence of a child seat by utilizing a 95 weight sensor in conjunction with a seat belt tension sensor.
• Prior art systems that rely solely on seat weight measurements often misdiagnose the presence of child seats due to the force exerted on the seat weight sensor by a tight seat belt.
• Yet another object of the instant invention is to provide a system and method for air bag suppression that employs direct sensor measurements in a simple algorithm to determine whether to deploy an air bag.
• the instant invention obviates the need for complex probabilistic algorithms thereby providing predictable system performance.
• a yet further object of the instant invention is to provide a system for air bag suppression utilizing a minimum of components to reduce vehicle assembly complexity and cost.
• Fig. 1 is a diagrammatical view of a preferred embodiment of the instant invention.
• Fig. 2 is a view of the instant invention taken along the line 2-2 of Fig. 1 .
• Fig. 3 is a diagrammatical view of a capacitive sensor in accordance with the instant invention.
• Fig. 4 is a diagrammatical view of an alternative capacitive sensor in accordance with the instant invention.
• Fig. 5 is a diagrammatical view of an hydrostatic weight sensor in accordance with the instant invention.
• Fig. 6 is a diagrammatical view of a bend sensor in accordance with the instant invention.
• Fig. 7 is a view taken along line 7-7 of Fig. 6.
• Fig. 8 is a diagrammatical view of an alternative seat belt tension sensor in accordance with the instant invention.
• a system 10 operatively coupled to an air bag control system 20 for controlling the inflation of an air bag 22 in a vehicle 30 having a vehicle seat 32 and a seat belt 34 comprises a seat weight sensor 40, a seat belt tension sensor 50, and a capacitive sensor 60 for sensing occupant position.
• An air bag control system processor 70 has a plurality of inputs 72, 74, and 76 operatively coupled to the weight sensor 40, the seat belt tension sensor 50, and the capacitive sensor 60, respectively.
• the processor 70 is further provided with a plurality of output signals 78 operatively coupled to a plurality of air bag squibs 24 to provide sufficient electrical current for the ignition thereof.
• the seat weight sensor 40 generates an output signal 42 responsive to the force exerted downwardly on the seat 32 and operatively coupled to the input 72 of the processor 70.
• the seat weight sensor 40 can comprise a plurality of force sensitive resistive elements 44 disposed within the vehicle seat 32 for measuring force.
• the force sensitive resistive elements 44 provide as an output signal 42 a variable electrical resistance responsive to the force exerted on the elements 44, operatively coupled to the input 72 of processor 70.
• the variable resistance output signal 42 is generally inversely proportional to the amount of force acting on the seat 32.
• a hydrostatic seat weight sensor 40 in accordance with the instant invention comprises a gas filled bladder 21 2 disposed within the vehicle seat 32 and a differential pressure sensor 220 operatively coupled to the bladder 21 2 for measuring the difference in pressure between the bladder and the atmosphere.
• the bladder 212 has a base area and a height, and is filled with a fluid, either gaseous or liquid.
• the differential pressure sensor 220 provides a weight sensor output signal 42 that is responsive to the force exerted downwardly on the seat 32.
• the sensor output signal 42 is operatively coupled to the input 72 of processor 70 thereby providing a measure of the force acting downwardly on the seat 32.
• the seat belt tension sensor 50 measures tensile force in seat belt 34 and generates an output signal 52 responsive thereto.
• the seat belt tension sensor 50 can comprise a bend sensor having a variable electrical resistance output signal 52 responsive to the change in the radius of curvature of a sensor material secured to a shaped flat spring.
• a bend tension sensor 100 for a seat belt 34 comprises a base 1 14 having a pair of spaced parallel front guide blocks 1 16 and a pair of spaced parallel rear guide blocks 1 18 depending therefrom.
• the parallel spaced front guide blocks 1 16 and the parallel spaced rear guide blocks 1 18 each have a plurality of cylindrical guide pins 120 disposed therebetween for guiding the seat belt 34.
• a shaped flat spring 130 has a first end 132 secured to the base 1 14 between the front and rear guide block pairs 1 16 and 1 18 respectively, and a free end 134 extending upwardly from the base 1 14 and disposed between the front 1 16 and rear 1 18 guide block pairs.
• a bend sensor 140 is secured to the shaped flat spring 130 using an electrically conductive adhesive at a point on the shaped flat spring 130 where the bend sensor 140 follows the curvature thereof when the flat spring free end 134 is biased toward the base 1 14.
• the bend sensor 140 comprises a flexible material having an output 52 responsive to a change in curvature of the bend sensor 140. As the bend sensor 140 is subjected to flexure, the radius of curvature of the flexible material changes thereby varying the electrical resistance as measured at the output 52.
• the bend sensor 140 typically has a nominal unflexed resistance variable up to a predetermined maximum resistance when flexed 90 degrees.
• the seat belt 34 is routed between the front guide blocks 1 16, either over or under at least one of the plurality of guide pins 120 disposed therebetween, over the flat spring 130 free end 134, between the rear guide blocks 1 18, and either over or under at least one of the plurality of guide pins 1 18 disposed therebetween.
• a pivot block 150 is secured to the base 1 14 directly beneath the shaped flat spring 130 and the bend sensor 140 secured thereto. The pivot block 150 provides a fulcrum around which the flat spring 130 and the bend sensor 140 are flexed when the free end 134 of flat spring 130 is biased downwardly.
• the free end 134 of the flat spring 130 is biased downwardly towards the base 1 14, thereby inducing curvature in the bend sensor 140.
• the pivot block 150 increases the amount of curvature induced in the bend sensor 140 for a given amount of movement of the free end 134 of the flat spring 30, thereby causing a
• a seat belt tension sensor 50 can comprise a Villari effect tension sensor as disclosed in copending U . S. Provisional Application Serial No. 60/067,071 herein incorporated by reference and 95 copending U . S. Provisional Application Serial No. 60/070,31 9 herein incorporated by reference, both assigned to the assignee of the instant invention.
• the Villari effect refers to the magnetic permeability responsive to 100 compression or tensile stresses of certain materials with magnetostrictive properties.
• the relative tension in the belt may be calculated .
• Fig. 8 illustrates the Villari effect sensor in accordance with the present invention.
• the Villari effect sensor 303 has one end mounted to tongue head flange 31 1 by a first anchoring means 309. The other end of the Villari effect sensor 303 is mounted to plunger 304 by a second anchoring means 309.
• a 110 spring 305 is disposed coaxially about Villari effect sensor rod 306 and is bound on one end by plunger 304 and on the other end by sensor housing radial flange 312.
• Sensor housing 308 encloses two chambers, a plunger chamber 313 and a tongue head chamber 314.
• Sensor housing 308 also has a mounting bolt hole 302 at one end for attaching the sensor to the frame of a 115 vehicle.
• Sensor housing plunger chamber 313 is disposed about plunger 304, spring 305, and one end of sensor rod 306.
• Sensor housing tongue head chamber 314 is separated from plunger chamber 313 by radial flange 312 and is disposed about tongue head flange 31 1 , the other end of sensor rod 306,
• Tongue head chamber 314 is further provided with sensor housing lip 310 that defines an orifice through which tongue shaft 315 passes. Sensor housing lip 310 will abut tongue head flange 31 1 in the event of sensor rod 306 breakage, thereby ensuring that the seat belt 34 will remain securely attached to the sensor. Tongue 307 extends from tongue shaft 315
• the Villari effect sensor 303 is further provided with an output 52 responsive to the change in magnetic permeability of the sensor rod 306 operatively coupled to the processor 70. As seat belt 34 tension increases plunger 304 compresses spring 305 against sensor housing
• the capacitive sensor 60 for example as taught in U . S. Patent No. 5,722,686 by Blackburn et al . , comprises a pair of spaced 140 electrically conductive electrodes 64 having a dielectric therebetween and a means for measuring the capacitance between the electrodes 64.
• the capacitive sensor 60 generates an electromagnetic field between the spaced electrodes 64 and generates an output signal 62 responsive to the amount of capacitance sensed 145 therebetween .
• the spaced electrodes 64 are mounted at a point relative to an air bag inflator door 26 such that the effective dielectric between the spaced electrodes 64 is air. An occupant within the electromagnetic field between the electrodes 64 affects the dielectric constant of the capacitive sensor 60, thereby varying the capacitance thereof as
• the 155 between the electrodes 64 increases thereby providing a measure of the proximity of an occupant to the inflator door 26.
• the sensor 60 When the capacitance between the electrodes 64 as measured by the sensor 60 reaches a predetermined level, the sensor 60 generates the output signal 62 responsive thereto .
• the processor 70 then inhibits the deployment of
• the aforementioned capacitive sensing method is also generally known in the art as electric field sensing, wherein the presence of a conductive or dielectric object is sensed.
• the human body has conductive and dielectric
• the spaced conductive electrodes 64 are located on, or very near to, the air bag inflator door 26, the danger zone of the air bag 22 can be constantly monitored . The response of the sensor is rapid enough to disable the air bag if the occupant enters the
• FIGs. 3 and 4 illustrate various configurations for the location of the capacitive sensor 60 conductive electrodes 64 within the scope of the instant invention.
• the sensor electrode 64 configuration comprises a single electrode 64 positioned proximate the inflator door which exhibits a stray capacitance relative to ground potential.
• the capacitance of this sensor electrode 64 configuration is influenced by the proximate presence of either dielectric or conductive objects and is detected using circuitry known to those of
• the single electrode sensor configuration is connected to an inductor L to form a series resonant LC circuit.
• the capacitive sensor 60 further comprises an associated detector circuit either conductively or magnetically linked to the LC circuit that produces an excitation signal which
• Inflation of the air bag 22 is always inhibited by the processor 70 when the seat belt tension is above a predetermined threshold thereby indicating the presence of a tightly belted child seat or other inanimate object. Additionally, air bag 22 inflation is inhibited when the seat belt tension is below a predetermined threshold and the force exerted on the
• the instant invention provides the ability to tailor the inflation 230 profile of the air bag 22 responsive to a sensed occupant at risk from full inflation thereof where the air bag control system 20 is equipped for variable inflation .
• the processor 70 disables one of the plurality of output signals 78 supplying firing current to the air bag squibs 24, thereby reducing the force with which the air bag 22 is deployed.
• the actual sensed quantity could be of different physical units, such as frequency, voltage, or current, whereby the sensed quantity varies in response to actual variations in distance of the object to be sensed.
• distances 260 measured by a position sensor may be transformed to corresponding distances relative to any point of reference which position is known relative to the associated position sensor.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Mathematical Physics (AREA)
• Theoretical Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Air Bags (AREA)

Priority Applications (5)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26723640

Family Applications (1)

Country Status (7)

Cited By (11)

Families Citing this family (57)

Citations (6)

Family Cites Families (21)

• 1998
  • 1998-05-11 US US09/075,582 patent/US6260879B1/en not_active Expired - Lifetime
  • 1998-05-12 JP JP54953798A patent/JP3998727B2/ja not_active Expired - Fee Related
  • 1998-05-12 DE DE69820869T patent/DE69820869T2/de not_active Expired - Fee Related
  • 1998-05-12 KR KR10-1999-7010043A patent/KR100529645B1/ko not_active Expired - Fee Related
  • 1998-05-12 WO PCT/US1998/009845 patent/WO1998051547A1/en not_active Ceased
  • 1998-05-12 EP EP98921202A patent/EP0981469B1/en not_active Expired - Lifetime
  • 1998-05-12 CA CA002285963A patent/CA2285963A1/en not_active Abandoned

Patent Citations (6)

Non-Patent Citations (1)

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