Vehicle occupant protection device

A vehicle occupant protection device comprising:

• a seat belt device having a selectable force limiter that is configured to switch a force limiter load, which an occupant receives from a seat belt at a time of frontal collision of a vehicle, from a high load to a low load;
• an airbag device that deploys an airbag in front of the occupant at the time of frontal collision;
• a movement direction detector that detects a direction in which a head region of the occupant will move relative to the vehicle at the time of frontal collision;
• an initial position detector that detects a position of the head region of the occupant prior to movement of the head region of the occupant at the time of frontal collision;
• and
• a control unit that makes a determination whether or not the head region will move outside of an area of protection by the airbag based on detection results of the movement direction detector and the initial position detector and, in a case in which it is determined that the head region of the occupant will move outside of the area of protection by the airbag while the airbag is deployed, maintains the high load of the force limiter load, wherein
• the movement direction detector has a front-rear acceleration sensor that is provided at a floor portion of the vehicle and that detects acceleration in a vehicle front-rear direction, and a left-right acceleration sensor that is provided at the floor portion of the vehicle and that detects acceleration in a vehicle left-right direction,
• the control unit stores a plurality of maps having acceleration in the vehicle front-rear direction as a vertical axis and acceleration in the vehicle left-right direction as a horizontal axis, and
• determination thresholds for determining whether or not the head region of the occupant will move outside of the protection area are respectively set in advance in the plurality of maps in accordance with different positions of the head region of the occupant prior to the movement.

A vehicle occupant protection device comprising:

• a seat belt device having a selectable force limiter that is configured to switch a force limiter load, which an occupant receives from a seat belt at a time of frontal collision of a vehicle, from a high load to a low load;
• an airbag device that deploys an airbag in front of the occupant at the time of frontal collision;
• a movement direction detector that detects a direction in which a head region of the occupant will move relative to the vehicle at the time of frontal collision;
• an initial position detector that detects a position of the head region of the occupant prior to movement of the head region of the occupant at the time of frontal collision;
• and
• a control unit that makes a determination whether or not the head region will move outside of an area of protection by the airbag based on detection results of the movement direction detector and the initial position detector and, in a case in which it is determined that the head region of the occupant will move outside of the area of protection by the airbag while the airbag is deployed, maintains the high load of the force limiter load, wherein
• the control unit (i) stores a time limit for a case in which the selectable force limiter is operated at the time of frontal collision, (ii) measures a time from detection of the frontal collision until the time limit with a timer, and (iii) determines whether or not the head region of the occupant will move outside of the protection area within a specified time calculated from the time limit.