Vehicle Seat Back Airbag with Occupancy Detection
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Solution Overview
Problem
Conventional vehicle seat designs with airbags installed in the seat back face structural complexity and instability issues when protecting front seat occupants from rear impacts, often resulting in inadequate absorption of collision forces and potential damage to rear seat occupants.
Innovation Solution
A vehicle with a front seat airbag that inflates within the seat back in response to collisions, utilizing sensors to detect rear seat occupancy, type, or load conditions, and controlling deployment to elastically support the front seat occupant and absorb impact forces, while canceling deployment when unnecessary to simplify the structure and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigidly configured support plate is provided behind the airbag to protect the front seat occupant, then the front seat occupant is protected from rearward movement during collision, but the support plate generates large impact forces when the rear seat occupant collides with the seat back from behind
Solution Approach 1:
The support structure is segmented into multiple functional zones: a soft cushioning layer (foam material) for receiving rearward impact from the rear seat occupant, and a rigid support plate positioned deeper in the seat back for providing structural support during front collision. This segmentation allows each zone to perform its specific function without interfering with the other, resolving the contradiction between protecting the front seat occupant and avoiding harm to the rear seat occupant.
Solution Approach 2:
Different regions of the seat back are assigned different mechanical properties: the rear portion (facing the rear seat) uses soft, compliant foam material to absorb impact energy from the rear seat occupant, while the front portion (facing the front seat) uses a rigid support plate to prevent excessive rearward movement of the front seat occupant. This local differentiation of material properties allows the seat back to simultaneously protect both occupants.
2Reliability
If an airbag is deployed to inflate toward the rear seat occupant side to protect the rear seat occupant, then the rear seat occupant is protected from forward movement during collision, but the structural complexity of the seat back increases
Solution Approach 1:
The existing airbag system is made multi-functional by configuring it to serve both front and rear seat occupants. The airbag is positioned and sized to provide protection to the front seat occupant during rearward movement while simultaneously protecting the rear seat occupant during forward movement. This universal design eliminates the need for separate airbag systems for each occupant, reducing structural complexity while maintaining comprehensive protection.
Solution Approach 2:
The cushioning function for the rear seat occupant and the support function for the front seat occupant are merged into a single integrated seat back structure. The foam cushion and support plate work together as a unified system, with the foam providing initial impact absorption and the support plate providing structural reinforcement. This merging eliminates the need for separate protective mechanisms, simplifying the overall structure.
3Reliability
If the airbag is deployed to inflate within the seat back to protect the front seat occupant, then the front seat occupant is protected from rearward movement, but the deployment may cause instability and inaccurate collision absorption when the rear seat is occupied
Solution Approach 1:
The seat back incorporates sensors (such as load cells or pressure sensors) that detect the presence and weight of occupants in both the front and rear seats. This feedback information is used by a control system to determine the appropriate airbag deployment strategy. When a rear seat occupant is detected, the system adjusts the airbag inflation pressure and timing to ensure stable deployment that protects the front seat occupant without causing instability or inaccurate collision absorption.
Solution Approach 2:
The airbag system transitions from a static, fixed-deployment design to a dynamic, adaptive system. The airbag's inflation characteristics (pressure, timing, duration) are dynamically adjusted based on real-time detection of occupancy conditions. This dynamic adaptation ensures stable and accurate collision absorption regardless of whether the rear seat is occupied, resolving the contradiction between protecting the front seat occupant and maintaining deployment stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces rear impact forces on front seat occupants and simplifies the airbag system, providing stable and accurate collision absorption without increasing structural complexity, thus enhancing passenger safety during rear collisions.
Implementation Method 1
the deployed/inflated airbag elastically supports an upper body of a front seat occupant and elastically receives an impact force exerted on a back surface of the seat back
Data Source
AI summary
A vehicle has a front seat in which an airbag is deployed so as to inflate in an interior of a seat back in response to a collision, and a rear seat disposed behind the front seat. The vehicle includes: a rear occupancy detector that detects the presence of a seat occupant in the rear seat; and a controller that controls deployment/inflation of the airbag. The airbag in the seat back elastically supports an upper body of a seat occupant of the front seat, and elastically receives an impact force exerted on a back surface of the seat back. The controller cancels deployment/inflation of the airbag when a seat occupant is not present in the rear seat.