Variable Force Limiter for Vehicle Occupant Protection
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Solution Overview
Problem
Existing vehicle occupant protection systems do not adequately consider variations in seating position and reclining angles, leading to suboptimal protection during frontal collisions, particularly when occupants are positioned further rearward within the airbag protection region, resulting in increased load on the chest region from seat belts.
Innovation Solution
A vehicle occupant protection device incorporating a seat belt with a variable force limiter mechanism, an airbag deployment system, and a seating position detection unit that adjusts the force limiter load based on the occupant's seating position and reclining angle to ensure optimal impact absorption during frontal collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the force limiter load is increased to reduce forward movement of the occupant, then occupant restraint is improved, but the load on the chest region increases causing potential injury
Solution Approach 1:
The force limiter load is made dynamically adjustable based on detected seating position and reclining angle. When the occupant is detected to be in a rearward seating position with increased distance to the airbag, the control unit increases the force limiter load to ensure adequate restraint. When the occupant is in a forward position, the load is reduced to prevent chest injury. This dynamic adjustment resolves the contradiction by adapting the restraint force to the actual geometric relationship between occupant and airbag.
Solution Approach 2:
The system changes the force limiter load parameter based on detected seating position parameters (front-rear position and reclining angle). By monitoring these parameters and adjusting the force limiter load accordingly, the system optimizes the balance between restraint effectiveness and chest region protection, resolving the technical contradiction between these two opposing requirements.
2Object-affected harmful factors
If the force limiter load is reduced to decrease chest region load, then occupant comfort is improved, but forward movement of the occupant increases reducing protection effectiveness
Solution Approach 1:
The force limiter load is dynamically adjusted based on the detected distance between the occupant and the airbag. When the occupant is in a forward seating position (smaller distance), the system reduces the force limiter load to decrease chest region load and improve comfort. When the occupant moves rearward (larger distance), the load is increased to maintain protection effectiveness. This dynamic parameter adjustment resolves the contradiction between comfort and protection.
Solution Approach 2:
The system modifies the force limiter load parameter in response to changes in seating position parameters. By establishing a relationship between occupant position and force limiter load setting, the system ensures that comfort is prioritized when protection distance is adequate, while protection effectiveness is maintained when the occupant is in rearward positions.
3Reliability
If the force limiter load is set to a high load to ensure protection when the seat is in the rear position, then occupant restraint is improved, but the load on the chest region increases causing potential injury
Solution Approach 1:
The system applies different force limiter load settings to different local conditions of seating position. Instead of using a uniform high load setting for all rear positions, the control unit calculates the specific distance between the occupant and the airbag based on front-rear position and reclining angle, and adjusts the force limiter load accordingly. This localized adjustment ensures adequate restraint for each specific position while minimizing unnecessary chest region load.
Solution Approach 2:
The force limiter load parameter is changed based on the specific seating position parameters detected. By establishing a functional relationship between seating position (front-rear distance and reclining angle) and force limiter load, the system optimizes restraint effectiveness for each local condition while avoiding excessive chest region load that would occur with a uniformly high load setting.
Data Source
AI summary
A vehicle occupant protection device includes a seat belt device having a variable force limiter mechanism that can change a force limiter load that an occupant who is sitting on a vehicle seat receives from a seat belt at a time of a frontal collision of a vehicle, an airbag device that deploys an airbag toward the front of the occupant at the time of the frontal collision, a seating position detection unit that detects a seating position at which the occupant is seated, and a control unit that reduces the force limiter load if, compared to a case in which the occupant is positioned within a standard seating region, the seating position of the occupant detected by the seating position detection unit is further toward a vehicle rear than the standard seating region and is within an airbag protection region in which the occupant is protected by the airbag.