Pedestrian Airbag Vent Control for Energy Absorption and Forward Guidance

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Solution Overview

Problem

Existing airbag systems for vehicles do not effectively prevent injury to pedestrians or bicyclists during collisions by efficiently managing the deployment and absorption of energy.

Innovation Solution

An airbag apparatus with a vent controller that adjusts the vent passage to discharge deployment gas at an early stage of collision, reducing the opening degree after initial energy absorption is completed, and further adjusts the vent passage to increase internal pressure for accelerating the pedestrian or bicyclist forward, thereby reducing relative speed and preventing injury.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the vent passage remains fully open during collision, then the airbag can discharge deployment gas quickly to absorb energy, but the airbag cannot maintain sufficient internal pressure to accelerate the pedestrian forward and reduce relative speed

Engineering Contradiction:

Improvecollision energy absorptionVSAvoidairbag internal pressure

Core Design Contradiction:

Loss of energyVSStress or pressure

Solution Approach 1:

The vent passage opening degree is dynamically adjusted during the collision process. The vent controller changes the opening degree from a first value (fully open) to a second value (partially closed) based on real-time detection of collision duration and energy absorption state, allowing the airbag to adapt its pressure and energy absorption characteristics throughout the collision event

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The vent passage undergoes periodic adjustment in two stages: initially fully open for rapid energy absorption, then partially closed to maintain pressure for acceleration. This staged, time-dependent control of the vent passage enables sequential fulfillment of different functional requirements during the collision process

Inventive Principle:

Principle #19Periodic action

2Stress or pressure

If the vent passage closes early to maintain airbag pressure, then the airbag can accelerate the pedestrian forward, but the airbag cannot effectively absorb collision energy at the early stage

Engineering Contradiction:

Improveairbag internal pressureVSAvoidcollision energy absorption

Core Design Contradiction:

Stress or pressureVSLoss of energy

Solution Approach 1:

The vent passage is maintained in a fully open state during the initial phase of collision to enable rapid energy absorption before the airbag needs to maintain pressure for acceleration. This preliminary action of keeping the vent open ensures that energy absorption occurs first, establishing the foundation for subsequent pressure-maintained acceleration

Inventive Principle:

Principle #10Preliminary action

3Speed

If the airbag maintains high internal pressure throughout collision, then the airbag can accelerate the pedestrian forward, but the airbag cannot effectively absorb collision energy through controlled discharge

Engineering Contradiction:

Improvepedestrian acceleration speedVSAvoidcollision energy absorption

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The internal pressure of the airbag is dynamically controlled through staged adjustment of the vent passage opening degree. The pressure transitions from an initial state of rapid discharge (low pressure) to a maintained state (high pressure) based on real-time collision parameters, enabling sequential energy absorption followed by acceleration

Inventive Principle:

Principle #15Dynamics

4Loss of energy

If the vent passage opens completely after energy absorption, then the deployment gas can be discharged, but the airbag cannot maintain sufficient pressure to prevent injury by reducing relative speed

Engineering Contradiction:

Improvedeployment gas dischargeVSAvoidinjury prevention effectiveness

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The vent passage follows a staged opening pattern: first fully open for energy absorption, then partially closed to maintain pressure for acceleration and injury prevention. This periodic, time-dependent control sequence ensures that gas discharge and pressure maintenance occur in the correct temporal order to fulfill both energy absorption and protection functions

Inventive Principle:

Principle #19Periodic action

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 system effectively absorbs collision energy, prevents injury by managing airbag pressure and relative speed, and guides the pedestrian or bicyclist onto the vehicle hood, enhancing safety during collisions.

Implementation Method 1

give to an inflator a command to supply deployment gas to the airbag and deploy the airbag

Methodology Applied

Scientific EffectGas expansion:

Implementation Method 2

detect a state of energy absorption by the airbag

Methodology Applied

Scientific EffectEnergy absorption:

Implementation Method 3

open and close a vent passage configured to discharge the deployment gas from the airbag

Methodology Applied

Scientific EffectGas discharge:

Data Source

PatentUS12454236B2Airbag apparatus

Publication Date: 2025.10.28 SUBARU CORP

AI summary

An airbag apparatus includes an airbag configured to be deployed forward of a front of a vehicle body of a vehicle, a collision determiner configured to establish a pre-crash determination when a collision probability is a predetermined threshold or higher, an airbag deployment controller configured to, in response to the pre-crash determination, give to an inflator a command to supply deployment gas to the airbag and deploy the airbag, a vent controller configured to open and close a vent passage configured to discharge the deployment gas from the airbag, and an energy absorption state detector configured to detect a state of energy absorption by the airbag. The vent controller is configured to open the vent passage at an early stage of collision with a collision object, and subsequently, reduce an opening degree of the vent passage when the energy absorption state detector detects a completion of energy absorption.