Air bag system having a control system for determining the exact inflating time of an air bag

• US 5,513,109 A
• Filed: 03/31/1995
• Issued: 04/30/1996
• Est. Priority Date: 06/22/1992
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Fujishima, Hiromichi
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/415,204
• Time in Patent Office: 396 Days
• Field of Search: 364/424.05, 280/734, 280/735, 180/274, 180/282, 307/10.1, 340/436, 340/438, 340/667
• US Class Current: 701/45
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/01332 by frequency or waveform analysis

Abstract

An air bag system able to inflate an air bag at an appropriate time, corresponding to different collision modes, with a simplified construction. The system is provided with a longitudinal acceleration sensor and an acceleration level computing means which computes the degree of acceleration. A computing device computes the rate of change of the acceleration and detects a characteristic of the rate of change, and sends the resultant data to a first judging device. The first judging device detects the presence of a collision based on the degree of the acceleration and the characteristic of the rate of change of the acceleration. A second judging device is provided in order to detect the presence of a collision based on the acceleration. An air bag driving signal is output based on the judgments made by the first and the second judging device.

Claims

1. An air bag system comprising:

an air bag driving apparatus including an air bag and means for inflating said air bag upon receipt of an air bag driving signal; and

an air bag control system comprising;

a first acceleration sensor which detects an acceleration of the body of an automobile in a longitudinal direction and outputs a first acceleration signal,

an acceleration level computing means, coupled to said first acceleration sensor, for computing a degree of acceleration and a longitudinal post-collision speed by using said first acceleration signal,

a rate of change computing means, coupled to said first acceleration sensor, for computing the rate of change of said first acceleration signal and detecting a predetermined characteristic of said rate of change, and outputting first resultant data,

a first judging means, coupled to said acceleration level computing means and said rate of change computing means, for judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal poet-collision speed and said first resultant data, and outputting a first judgment result,

a second judging means, coupled to said acceleration level computing means, for computing a period of time during which said degree of acceleration exceeds a predetermined value and judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said rate of change when said period of time exceeds a predetermined value, and outputting a second judgment result, and

an air bag driving signal outputting means, coupled to said first and said second judging means, for determining an occurrence of a collision of said automobile based on said first and said second judgment results and outputting said air bag driving signal to said air bag driving apparatus.

2. The air bag system as claimed in claim 1, wherein said predetermined characteristic detected by said rate of change computing means comprises a value representing the integral of said rate of change over a period of time during which said rate of change exceeds a predetermined value.

3. The air bag system as claimed in claim 1, wherein said first judging means judges that a collision has occurred when all of said degree of acceleration, said longitudinal post-collision speed and said predetermined characteristic of said rate of change are greater than respective predetermined values.

4. The air bag system as claimed in claim 1, wherein said second judging means judges that a collision has occurred when all of said degree of acceleration, said longitudinal post-collision speed, said rate of change and said period of time are greater than respective predetermined values.

5. The air bag system as claimed in claim 1, wherein said air bag driving signal outputting means outputs said air bag driving signal upon receipt of either said first judgment result or said second judgment result.

6. The air bag system as claimed in claim 1, wherein said air bag control system further comprises a deceleration judging means, coupled to said acceleration level computing means and said air bag driving signal outputting means, for judging an occurrence of a collision of said automobile by observing whether or not said longitudinal post-collision speed exceeds a predetermined value and outputting a post-collision speed judgment result, and said air bag driving signal outputting means determines the occurrence of a collision of said automobile based on said first and said second judgement results and said post-collision speed judgment result.

7. An air bag system comprising:

an air bag driving apparatus including an air bag and means for inflating said air bag upon receipt of an air bag driving signal; and

an air bag control system comprising,

a first acceleration sensor which detects an acceleration of the body of an automobile in a longitudinal direction and outputs a first acceleration signal,

an acceleration level computing means, coupled to said first acceleration sensor, for computing a degree of acceleration and a longitudinal post-collision speed by using said first acceleration signal,

a rate of change computing means, coupled to said first acceleration sensor, for computing the rate of change of said first acceleration signal and detecting a predetermined characteristic of said rate of change, and outputting first resultant data, wherein said predetermined characteristic detected by said rate of change computing means comprises the number of peaks of a rate of change waveform defined by said rate of change of said first acceleration signal exceeding a predetermined value,

a first judging means, coupled to said acceleration level computing means and said rate of change computing means, for judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed and said first resultant data, and outputting a first judgment result,

a second judging means, coupled to said acceleration level computing means, for computing the period of time during Which said degree of acceleration exceeds a predetermined value for a first predetermined period of time and judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said rate of change and said period of time, and outputting a second judgment result, and

an air bag driving signal outputting means, coupled to said first and said second judging means, for determining an occurrence of a collision of said automobile based on said first and said second judgment results and outputting said air bag driving signal to said air bag driving apparatus,

8. An air bag system comprising:

an air bag driving apparatus including an air bag and means for inflating said air bag upon receipt of an air bag driving signal; and

an air bag control system comprising;

a first acceleration sensor which detects an acceleration of the body of an automobile in a longitudinal direction and outputs a first acceleration signal,

an acceleration level computing means, coupled to said first acceleration sensor, for computing a degree of acceleration and a longitudinal post-collision speed by using said first acceleration signal,

a rate of change computing means, coupled to said first acceleration sensor, for computing the rate of change of said first acceleration signal and detecting a predetermined characteristic of said rate of change, and outputting first resultant data, wherein said predetermined characteristic detected by said rate of change computing means comprises a value representing the area of the peaks of a rate of change waveform defined by said rate of change of said first acceleration signal exceeding a predetermined value for a first predetermined period of time,

a first judging means, coupled to said acceleration level computing means and said rate of change computing means, for judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed and said first resultant data, and outputting a first judgment result,

a second judging means, coupled to said acceleration level computing means, for computing the period of time during which said degree of acceleration exceeds a predetermined value and judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said rate of change and said period of time, and outputting a second judgment result, and

an air bag driving signal outputting means, coupled to said first and said second judging means, for determining an occurrence of a collision of said automobile based on said first and said second judgment results and outputting said air bag driving signal to said air bag driving apparatus.

9. An air bag system comprising:

an air bag driving apparatus including an air bag and means for inflating said air bag upon receipt of an air bag driving signal; and

an air bag control system comprising,

a first acceleration sensor which detects an acceleration of the body of an automobile in a longitudinal direction and outputs a first acceleration signal,

an acceleration level computing means, coupled to said first acceleration sensor, for computing a degree of acceleration and a longitudinal post-collision speed by using said first acceleration signal,

a rate of change computing means, couples to said first acceleration sensor, for computing the rate of change of said first acceleration signal and detecting a predetermined characteristic of said rate of change, and outputting first resultant data,

a first judging means, coupled to said acceleration level computing means and said rate of change computing means, for judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed and said first resultant data, and outputting a first judgment result,

a second judging means coupled to said acceleration level computing means, for computing the period of time during which said degree of acceleration exceeds a predetermined value for a first predetermined period of time and judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said rate of change and said period of time, and outputting a second judgment result,

an air bag driving signal outputting means, coupled to said first and said second judging means, for determining an occurrence of a collision of said automobile based on said first and said second judgment results and outputting said air bag driving signal to said air bag driving apparatus, and

a weighing means for weighing said first judgment result and said second judgment result with respective predetermined weighing factors, and said air bag driving signal outputting means determines that a collision has occurred when the sum of said weighted first judgment result and weighted second judgment result exceeds a predetermined value.

10. An air bag system comprising:

an air bag driving apparatus including an air bag and means for inflating said air bag upon receipt of an air bag driving signal; and

an air bag control system comprising;

a first acceleration sensor which detects an acceleration of the body of an automobile in a longitudinal direction and outputs a first acceleration signal,

an acceleration level computing means, coupled to said first acceleration sensor, for computing a degree of acceleration and a longitudinal post-collision speed by using said first acceleration signal,

a rate of change computing means, coupled to said first acceleration sensor, for computing the rate of change of said first acceleration signal and detecting a predetermined characteristic of said rate of change, and outputting first resultant data,

a first judging means, coupled to said acceleration level computing means and said rate of change computing means, for judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed and said first resultant data, and outputting a first judgment result,

a second judging means, coupled to said acceleration level computing means, for computing the period of time during which said degree of acceleration exceeds a predetermined value for a first predetermined period of time and judging an occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said rate of change and said period of time, and outputting a second judgment result,

a second acceleration sensor which detects an acceleration in the transverse direction of said body of said automobile and outputs a second acceleration signal,

a transverse post-collision speed computing means, coupled to said second acceleration sensor, for computing a transverse post-collision speed by using said second acceleration signal and deriving a factor from said transverse post-collision speed,

a third judging means, coupled to said transverse post-collision speed computing means and said acceleration level computing means, for judging the occurrence of a collision of said automobile by using said degree of acceleration, said longitudinal post-collision speed, said range of change and said factor of said transverse post-collision speed, said third judging means outputting a third judgment result, and

an bag driving signal outputting means, coupled to said first, said second and said third judging means, for determining an occurrence of a collision of said automobile based on said first, said second and said third judgment results and outputting said air bag driving signal to said air bag driving apparatus.

11. The air bag system as claimed in claim 10, wherein said factor derived from said transverse post-collision speed computed by said transverse post-collision speed computing means comprises a value representing an absolute value of an integration of said transverse post-collision speed for said first predetermined period of time.

12. The air bag system as claimed in claim 10, wherein said factor derived from said transverse post-collision speed computed by said transverse post-collision speed computing means comprises a value representing the maximum value of said transverse post-collision speed for a second predetermined period of time.

13. The air bag system as claimed in claim 10, wherein said third judging means judges that a collision has occurred when all of said degree of acceleration, said longitudinal post-collision speed, said rate of change and said factor of said transverse post-collision speed are greater than respective predetermined values.

14. The air bag system as claimed in claim 10, wherein said air bag driving signal outputting means outputs said air bag driving signal upon receipt of either said first judgment result, said second judgment result or said third judgment result.

15. The air bag system as claimed in claim 10, wherein said air bag control system further comprises a weighting means for weighting said first judgment result, said second judgment result and said third judgment result with respective predetermined weighting factors, said air bag driving signal outputting means determines that a collision has occurred when the sum of said weighted first judgment result, weighted second judgment result, and weighted third judgment result exceeds a predetermined value.