Integrated circuit for air bag system

• US 20040084882A1
• Filed: 01/24/2003
• Published: 05/06/2004
• Est. Priority Date: 01/25/2002
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Oda, Shingo, Okamoto, Mitsuyasu
• Granted Patent: US 7,168,737 B2
• Time in Patent Office: Days
• US Class Current: 280/735
• CPC Class Codes: B60R 2021/01075 between the airbag control unit and pyrotechnic fuses or equivalent actuators
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/017 including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
• CPC Class Codes: B60R 21/0173 Diagnostic or recording means therefor
• CPC Class Codes: B60R 21/26 characterised by the inflation fluid source or means to control inflation fluid flow arrangement or mounting thereof to the vehicle B60R21/20; blasting cartridges for producing gas under pressure in general F42B3/04; initiators or igniters therefor F42B3/10
• CPC Class Codes: F42B 3/121 Initiators with incorporated integrated circuit

Abstract

The present invention provides an integrated circuit for an air bag system which can be reduced in weight while maintaining an excellent operation performance.

The present invention provides an integrated circuit for an air bag system which is used in an air bag system having an ECU and a module case connected to the ECU and accommodating a gas generator and an air bag, wherein, in the air bag system, two bus line passing through the ECU is provided to supply currents and the like, and individual gas generators accommodated in the module cases are connected operationally by conductors branched from the bus lines,

the igniters incorporated in the gas generator is each electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through the conductors, and

the integrated circuit provided in the igniter is recorded with information to exhibit required functions, and a current for igniting the priming is supplied to the igniters through a capacitor.

Claims

1. An integrated circuit for an air bag system, provided inside one or at least two igniters incorporated in the plural of the gas generators and used in an air bag system comprising an electronic control unit connected to a power source and an impact detecting sensor, and plural module cases which are connected to the electronic control unit and accommodate plural gas generators and plural air bags, wherein,

in the air bag system, a bus line comprising plural loop wires which pass through the electronic control unit is provided to supply and transmit currents and required information, and individual gas generators accommodated in the plural module cases are connected operationally by plural conductors branched at predetermined portions from the bus line,

the one or at least two igniters incorporated in the gas generator is each electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through plural conductors, and

the integrated circuit provided in the igniter is recorded with information to exhibit required functions, and a current for igniting the priming is supplied to the one or at least two igniters through a capacitor.

2. An integrated circuit for an air bag system according to claim 1, which has a circuit having a function for detecting abnormality of the heat generating portion of the igniter in the gas generator, a circuit having a function for identifying each of the plural gas generators, and a circuit having a function for detecting a malfunction of the capacitor.

10. An integrated circuit for an air bag system according to any one of claims 1 to 9, further comprising a circuit for preventing the igniter from being activated erroneously by a noise made outside the igniter.

11. An integrated circuit for an air bag system according to any one of claims 1 to 10, further comprising a discharging waveform converting circuit which converts a signal waveform of a current, for igniting the priming, stored in the capacitor for each igniter.

12. An integrated circuit for an air bag system according to any one of claims 1 to 11, wherein the discharging waveform converting circuit exists.

13. An integrated circuit for an air bag system according to any one of claims 1, 2, and 8 to 11, further comprising a circuit which, among the currents from the bus circuit for charging the capacitor and the required information, is a circuit, for charging the capacitor, having a function for rectifying a current to flow into a capacitor to be charged

14. An integrated circuit for an air bag system according to claim 13, wherein a function for amplifying at least one of a rectified voltage for charging a capacitor and a voltage applied to the bus line exists.

15. A method for controlling operation of an air bag system using an integrated circuit for an air bag system described in claim 1, 2, 13 or 14, wherein a time period for supplying a current from the capacitor to the heat generating portion is the period from the point where a current value reaches the current value corresponding to 5% of the maximum current value to the point where it is reduced down to the value corresponding to 5% of the maximum current value, which is within 500 μ

sec.

16. A method for controlling operation of an air bag system according to claim 15, wherein, when the waveform of the current supplied from the heat generating portion from the capacitor starts discharging at a time of time t=0, the waveform is a discharging waveform expressed by the following formula (I):

i(t)=(V0/R)×

e<sup>−

t/CR</sup> 

 

(I)

(In the formula, V0 represents a capacitor charging voltage (V) R represents a circuit resistance (Ω

), C represents a capacitor capacitance (μ

F), t represents a time (μ

sec), and i represents a current (A)).

17. A method for controlling operation of an air bag system according to claim 15 or 16, wherein, when a period in which a stable current supplying is being maintained after reaching a desired current value is defined as t (μ

sec) and a period from a start of waveform rising to stopping of current supplying for making the heat generating portion generate a heat is defined as T (μ

sec), these t and T (t/T) satisfies 0≦

t/T<

0.2 or 0.5<

t/T<

1.

18. A method for controlling operation of an air bag system using an integrated circuit for an air bag system described in claim 1 or 2, which is a method for controlling operation of an air bag system using the above integrated circuit for an air bag system, wherein a current to the heat generating portion is supplied as an ignition pulse, and the current is supplied such that the width of the ignition pulse becomes 20 to 500 μ

sec.

19. A method for controlling operation of an air bag system according to claim 18, wherein the width of the ignition pulse is 40 to 100 μ

sec.

3. An integrated circuit for an air bag system which is provided in one or at least two igniters incorporated into the plural gas generators and used in an air bag system comprising an electronic control unit connected to a power source and an impact detecting sensor, and plural module cases which are connected to the electronic control unit and accommodate the plural gas generators and plural air bags, wherein

in the air bag system, a bus line comprising plural loop wires which pass through the electronic control unit is provided to supply and transmit currents and required information, and individual gas generators accommodated in the plural module cases a reconnected operationally by plural conductors branched at predetermined portions from the bus line,

the one or at least two igniters incorporated in the gas generator is each electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through plural conductors, and

the integrated circuit provided inside the igniter has a circuit having a function to detect abnormality of the heat generating portion of the igniter, and the abnormality of the igniter to be detected includes at least one of the group comprising disconnection, a loose contact between the heat generating portion and the priming, or abnormality of a resistance value of the heat generating portion.

4. An integrated circuit for an air bag system according to claim 3, wherein the a loose contact between the heat generating portion of the igniter and the priming is to be detected by detecting a change in the resistance value due to a temperature change of the heat generating portion as a voltage change.

5. An integrated circuit for an air bag system which is provided in one or at least two igniters incorporated into the plural gas generators and used in an air bag system comprising an electronic control unit connected to a power source and an impact detecting sensor, and plural module cases which are connected to the electronic control unit and accommodate the plural gas generators and plural air bags, wherein

in the air bag system, a bus line comprising plural loop wires which pass through the electronic control unit is provided to supply and transmit currents and required information, and individual gas generators accommodated in the plural module cases are connected operationally by plural conductors branched at predetermined portions from the bus line,

the one or at least two igniters incorporated in the gas generator is each electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through plural conductors, and the integrated circuit provided inside the igniter has a function to identify each of the plural gas generators.

6. An integrated circuit for an air bag system according to claim 5, wherein the information to exhibit an function for identifying each of the plural gas generators is recorded after assembling the gas generator.

7. An integrated circuit for an air bag system according to claim 5, wherein the information to exhibit an function for identifying each of the plural gas generators is recorded after assembling the gas generator in the module case or after mounting into a vehicle.

8. An integrated circuit for an air bag system which is provided in one or at least two igniters incorporated into the plural gas generators and used in an air bag system comprising an electronic control unit connected to a power source and an impact detecting sensor, and plural module cases which are connected to the electronic control unit and accommodate the plural gas generators and plural air bags, wherein

in the air bag system, a bus line comprising plural loop wires which pass through the electronic control unit is provided to supply and transmit currents and required information, and individual gas generators accommodated in the plural module cases are connected operationally by plural conductors branched at predetermined portions from the bus line,

the one or at least two igniters incorporated in the gas generator is each electric igniter which is provided with a heat generating portion and a priming coming in contact with the heat generating portion, and the igniter and the bus line are connected to each other through plural conductors, and

the integrated circuit provided inside the igniter has a function to detect a malfunction of the capacitor storing power supplied to the heat generating portion provided in the igniter.

9. An integrated circuit for an air bag system according to claim 8, wherein the information to exhibit a function for detecting a malfunction of the capacitor is information for measuring a pulse response or a dielectric dissipation factor.