Abstract: A seat restraint buckle and tension sensing assembly for a seat restraint system in a vehicle includes a buckle assembly having a housing for receiving a portion of a latch plate of the seat restraint system. The buckle assembly senses latching of the latch plate. The seat restraint buckle and tension sensing assembly also includes a tension sensing assembly disposed in the housing and cooperating with belt webbing of the seat restraint system for sensing a tension level in the seat restraint system.

Abstract: An improved method of selectively suppressing deployment of a vehicular inflatable restraint utilizes dynamic variation in the apparent weight of a vehicle occupant to infer a free mass of the seat occupant. The free mass of the occupant is inferred by filtering out portions of a weight-responsive signal due to occupant position adjustment and inferring the occupant free mass based on the variation of the apparent weight with respect to the variation in vertical acceleration of the vehicle. The decision to allow or suppress deployment of the restraint is determined based on a comparison of the static weight reading with at least one threshold, and the occupant free mass is used to adjust the threshold in a direction to minimize the overall variability of the system. Measures of the seat belt tension and the seat temperature are also be used to adjust the threshold in a direction to minimize system variability.

Abstract: A tension sensing assembly for a seat restraint system in a vehicle includes a housing for operative connection to vehicle structure and at least one spring disposed in the housing. The tension sensing assembly also includes at least one magnet disposed in the housing and a Hall effect sensor disposed in the housing and cooperable with the at least one magnet. The tension sensing assembly further includes a movable mechanism at least partially disposed in the housing and cooperable with belt webbing of the seat restraint system and the at least one spring to move the at least one magnet relative to the Hall effect sensor to change an output of the Hall effect sensor to indicate a first tension level and a second tension level in the seat restraint system when the at least one spring is deflected.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a minimum weight adult and a child seated on a booster seat. An early characterization of the seat occupant is made in an interval following a transition event such as a door opening or ignition state change that activates the occupant detection system. During this interval, an initial characterization routine monitors the seat belt tension and the raw seat pressure to identify signal values characteristic of a minimum weight adult or a child seated on a booster seat. If the indicated occupant weight during subsequent operation of the vehicle is inconsistent with the initial characterization, the initial characterization is discarded, and the seat occupancy is characterized based on the indicated occupant weight.

Abstract: A seat restraint buckle and tension sensing assembly for a seat restraint system in a vehicle includes a buckle assembly having a housing for receiving a portion of a latch plate of the seat restraint system. The buckle assembly senses latching of the latch plate. The seat restraint buckle and tension sensing assembly also includes a tension sensing assembly disposed in the housing and cooperating with belt webbing of the seat restraint system for sensing a tension level in the seat restraint system.

Abstract: A tension sensing assembly for a seat restraint system in a vehicle includes a housing for operative connection to vehicle structure and at least one spring disposed in the housing. The tension sensing assembly also includes at least one magnet disposed in the housing and a Hall effect sensor disposed in the housing and cooperable with the at least one magnet. The tension sensing assembly further includes a movable mechanism at least partially disposed in the housing and cooperable with belt webbing of the seat restraint system and the at least one spring to move the at least one magnet relative to the Hall effect sensor to change an output of the Hall effect sensor to indicate a first tension level and a second tension level in the seat restraint system when the at least one spring is deflected.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a minimum weight adult and a child seated on a booster seat. An early characterization of the seat occupant is made in an interval following a transition event such as a door opening or ignition state change that activates the occupant detection system. During this interval, an initial characterization routine monitors the seat belt tension and the raw seat pressure to identify signal values characteristic of a minimum weight adult or a child seated on a booster seat. If the indicated occupant weight during subsequent operation of the vehicle is inconsistent with the initial characterization, the initial characterization is discarded, and the seat occupancy is characterized based on the indicated occupant weight.

Abstract: An improved method of selectively suppressing deployment of a vehicular inflatable restraint utilizes dynamic variation in the apparent weight of a vehicle occupant to infer a free mass of the seat occupant. The free mass of the occupant is inferred by filtering out portions of a weight-responsive signal due to occupant position adjustment and inferring the occupant free mass based on the variation of the apparent weight with respect to the variation in vertical acceleration of the vehicle. The decision to allow or suppress deployment of the restraint is determined based on a comparison of the static weight reading with at least one threshold, and the occupant free mass is used to adjust the threshold in a direction to minimize the overall variability of the system. Measures of the seat belt tension and the seat temperature are also be used to adjust the threshold in a direction to minimize system variability.

Abstract: A seat restraint tension sensing assembly for a seat restraint system in a vehicle includes a latch plate for connection to belt webbing of the seat restraint system. The seat restraint tension sensing assembly also includes a buckle assembly for receiving the latch plate. The seat restraint tension sensing assembly includes at least one magnet mounted to the latch plate and at least one Hall effect sensor associated with either one of the latch plate and the buckle assembly and cooperable with the at least one magnet. The seat restraint tension sensing assembly further includes a movable actuator mounted to the latch plate and cooperable with the belt webbing to move the at least one magnet relative to the at least one Hall effect sensor to change an output of the at least one Hall effect sensor to indicate a tension level in the seat restraint system.

Abstract: An improved vehicle seat occupant weight estimation method detects weight applied to both the seat cushion and the floor forward of the seat, and increases the measured seat weight of the occupant to account for occupant weight off-loaded to the floor. Fluid-filled bladders or other sensors are arranged to detect occupant seat weight and the weight applied to the vehicle floor forward of the seat. Upon opening of a vehicle door or an off-to-on transition of the vehicle ignition switch, the seat and floor weight sensors are monitored to detect the presence of an occupant. When the seat becomes occupied, or whenever there is a large change in the measured seat weight, the seat and floor weight are recorded, the occupant weight is estimated according to the recorded seat weight, and the inflatable restraints are allowed or suppressed based on the estimated occupant weight.

Abstract: An improved occupant detection system and method includes a fluid-filled polymeric seat cushion bladder defining multiple fluid-filled chambers corresponding to different areas of the seat cushion, with no fluid flow between such chambers. Fluid pressures in the various individual chambers are detected and processed to develop a weight estimation that is compensated for occupant position. The chambers are configured to detect occupant weight in at least forward, rearward, inboard and outboard regions of the bottom seat cushion. When the detected pressures are unevenly distributed and the pressure in the forward, rearward, inboard or outboard regions of the seat exceeds the average pressure by at least a predetermined amount, a composite pressure indicative of occupant weight is adjusted in a direction to bias the suppression status in favor of allowing restraint deployment, unless the occupant is forwardly positioned on a seat that is also forwardly positioned.

Abstract: An improved occupant detection system and method includes a fluid-filled polymeric seat cushion bladder defining multiple fluid-filled chambers corresponding to different areas of the seat cushion, with no fluid flow between such chambers. Fluid pressures in the various individual chambers are detected and processed to develop a weight estimation that is compensated for occupant position. The chambers are configured to detect occupant weight in at least forward, rearward, inboard and outboard regions of the bottom seat cushion. When the detected pressures are unevenly distributed and the pressure in the forward, rearward, inboard or outboard regions of the seat exceeds the average pressure by at least a predetermined amount, a composite pressure indicative of occupant weight is adjusted in a direction to bias the suppression status in favor of allowing restraint deployment, unless the occupant is forwardly positioned on a seat that is also forwardly positioned.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a child or small adult and a tightly cinched child seat based on a variance in the sensed occupant weight and a variance in the vehicle acceleration. The weight variance and acceleration variance are used to determine a relative or normalized variance that compensates for the effects of operating the vehicle on a rough road surface. The occupant is characterized as a child seat if the normalized variance is below a first threshold for a predetermined interval, and as a child or small adult if the normalized variation exceeds a second threshold for a predetermined interval.

Abstract: An improved weight-based occupant characterization method reliably distinguishes between a child or small adult and a tightly cinched child seat based on a variance in the sensed occupant weight and a variance in the vehicle acceleration. The weight variance and acceleration variance are used to determine a relative or normalized variance that compensates for the effects of operating the vehicle on a rough road surface. The occupant is characterized as a child seat if the normalized variance is below a first threshold for a predetermined interval, and as a child or small adult if the normalized variation exceeds a second threshold for a predetermined interval.

Abstract: An improved weight estimation apparatus in which an elastomeric bladder is supported on a semi-rigid backer board which is installed in a vehicle seat between the seat cushion and an underlying spring suspension. The bladder is secured onto the backer board, and the backer board is attached to the seat, enabling proper and consistent placement of the bladder relative to the seat surface. The backer board provides the reaction surface for the bladder, and masks non-uniformities of the seat structure. Additionally, the backer board will reduce or eliminate the effect of objects lying on the floor under the seat, which might otherwise pinch the bladder and produce weight estimation errors. Further, the board tends to protect the bladder from damage due to sharp objects, pinching by the suspension elements, and the effects of wires or cables routed through the seat.

Abstract: An improved occupant weight detection system measures the pressure in a fluid-filled bladder disposed in or under a foam seat cushion as an indication of occupant weight, and periodically adjusts the pressure vs. occupant weight relationship to compensate for changes due to aging and usage of the foam seat cushion. The system controller develops an aging adjustment value based on a measure of the cumulative aging and usage of the seat, and uses the developed adjustment value to compensate the operation of the system. The aging adjustment value is determined primarily as a function of occupant weight and time of seat occupancy, and the compensation is achieved by using the aging adjustment value to adjust either the estimated weight, or a threshold to which the measured pressure is compared for purposes of deciding if restraint deployment should be enabled.

Abstract: An improved occupant weight detection system measures the pressure in a fluid-filled bladder disposed in or under a foam seat cushion as an indication of occupant weight, and periodically adjusts the pressure vs. occupant weight relationship to compensate for changes due to aging and usage of the foam seat cushion. The system controller develops an aging adjustment value based on a measure of the cumulative aging and usage of the seat, and uses the developed adjustment value to compensate the operation of the system. The aging adjustment value is determined primarily as a function of occupant weight and time of seat occupancy, and the compensation is achieved by using the aging adjustment value to adjust either the estimated weight, or a threshold to which the measured pressure is compared for purposes of deciding if restraint deployment should be enabled.

Abstract: An improved method of producing a fluid filled elastomeric bladder for occupant weight sensing involves annealing the bladder material prior to its installation in a vehicle seat so as to quickly relieve initial stress due to stretching of the bladder material which occurs during fluid injection. In a preferred implementation, the initial stress is relieved by immersing the fluid-filled bladders in heated water for a time period on the order of 60 seconds or more. Alternatively, the bladder material may be heated with steam or radiant heat, by injecting heated fluid into the bladder, or by injecting heated air into an empty bladder before fluid injection. In each case the initial stress is quickly relieved, substantially eliminating a potential source of error in the sensed weight.

Abstract: An improved weight-based occupant characterization method that can inexpensively and reliably distinguish between a child or small adult and a tightly cinched child seat. When the sensed weight is in a specified range that could be produced by a tightly cinched child seat, the system characterizes the occupant based on a detected variation in sensed weight during movement of the vehicle. If the variance of the sensed weight is below a threshold for a predetermined interval, the occupant is characterized as a child seat, since a tightly cinched seat belt severely restricts variance. If the variance exceeds the threshold for a predetermined interval, the occupant is characterized as a child or small adult. A correlative factor that can be used in distinguishing between a child seat and a child or small adult is determined by computing a slope reversal rate, or frequency, of the measured weight.