Circuit arrangement for triggering a vehicle passenger protection system

• US 5,446,442 A
• Filed: 06/09/1994
• Issued: 08/29/1995
• Est. Priority Date: 03/31/1992
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Swart, Marten, Eigler, Jurgen, Vogt, Richard
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): Oda, Christine K.
• Application Number:
  US08/257,480
• Time in Patent Office: 446 Days
• Field of Search: 340/438, 340/436, 340/670, 280/735, 180/282
• US Class Current: 340/438
• 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

Abstract

Circuit arrangement for triggering a vehicle passenger protection system, having a plurality of triggers (ZP1, ZP2, ZP3), through which (ZP1, ZP2, ZP3) in the event of a sufficiently serious accident a current impulse is conducted in each case, which for its part is intended to trigger the protection, one or more triggering switches (SS in FIGS. 1 and 2), the switching path of which (SS) in each case is non-conductive before the accident, and in the event of a sufficiently serious accident makes the transition to its conductive state and thus causes the current impulse through the triggers (ZP1, ZP2, ZP3), a plurality of current branches (ZP1/C2, ZP2/C5, ZP3/C9), which in each case contain at least one of the triggers, for example a primer capsule (ZP1, ZP2, ZP3), and a capacitor (C2, C5, C9), and a parallel circuit which is formed by the parallel circuit of the current branches (ZP1/C2, ZP2/C5, ZP3/C9). Before the accident the capacitor (C2, C5, C9) of each of the current branches (ZP1/C2, ZP2/C5, ZP3/C9) is connected during the journey to a voltage source (VCC30, GND according to FIG. 3 ), and thus is charged before the accident to an ignition voltage (approximately 30 V). The capacitor (C2, C5, C9) of each of the current branches (ZP1/C2, ZP2/C5, ZP3/C9) has both so high a self-capacitance (270μF) and, before the accident, so high an ignition voltage (approximately 30 V), that during the accident it (C2, C5, C9) delivers the current impulse with reliably sufficient energy in each case to trigger the trigger/triggers (ZP1, ZP2, ZP3) of the relevant current branch (ZP1/C2, ZP2/C5, ZP3/C9) despite any additional energy losses (in D2, D 8, D11, Q6, Q9, Q13, Q16, R41, R42, R56).

Claims

1. A circuit arrangement for triggering a vehicle passenger protection system in a vehicle having an engine in the event of an accident, comprising:

a voltage source operatively connected to a parallel circuit having at least two current branches,

current branches of said at least two current branches each having a dedicated trigger, wherein a respective dedicated trigger of a respective current branch of said at least two current branches conducts, during the accident, a current impulse,

said current branches of said at least two current branches each having a dedicated capacitor charged by the voltage source, each dedicated capacitor of said dedicated capacitors of said at least two current branches having both a high self-capacitance and a high ignition voltage, wherein during the accident a respective dedicated capacitor of said respective current branch delivers to the respective dedicated trigger the current impulse that triggers the protection system,

current branches of the at least two current branches each having a decoupling element, wherein during the accident decoupling elements of said at least two current branches mutually decouple current impulses flowing in said at least two current branches,

said current branches of said at least two current branches each having an individual triggering switch, a respective individual triggering switch of said respective current branch being connected in parallel to said respective dedicated trigger and said respective dedicated capacitor wherein the respective individual triggering switch is conductive during the accident thereby permitting the respective current impulse to flow through the respective dedicated trigger and

at least one common triggering switch, which is connected in series with individual triggering switches of the at least two current branches, wherein the at least one common triggering switch is conductive during the accident thereby permitting the respective current impulse to flow through the respective dedicated trigger,

said current branches of said at least two current branches each having at least one measuring point connected in series with the capacitor thereof and the dedicated trigger thereof, at least one of the capacitor and the dedicated trigger of each current branch being connected before the accident by means of the voltage source to continuous-operation voltages which are testable via said measuring point; and

in each of said current branches of said at least two current branches the decoupling element thereof, the capacitor thereof, the trigger thereof and the measuring point thereof forming a series circuit.

2. The circuit arrangement as claimed in claim 1, wherein for checking operation of the respective current branch, a measuring current flows through the respective current branch via the at least one measuring point of the respective current branch, the individual triggering switch of the respective current branch and the common triggering switch being non-conductive during the checking operation.

3. The circuit arrangement as claimed in claim 1, wherein the circuit arrangement further comprises a plurality of further measuring points, potentials of the plurality of further measuring points being measured during operation of the vehicle, at least upon starting the engine.

4. The circuit arrangement as claimed in claim 3, wherein the circuit arrangement further comprises defined switching points and test switches which apply at least one test potential to the defined switching points of the circuit arrangement in order to measure the potentials of the plurality of further measuring points.

5. The circuit arrangement as claimed in claim 4, wherein said test potentials are applied to circuit elements of the circuit arrangement via said defined switching points and wherein said test potentials simulate actual potentials occurring at least approximately at these circuit elements during fault-free operation during the accident, said circuit elements being at least said dedicated triggers and said dedicated capacitors of said at least two current branches.

6. The circuit arrangement as claimed in claim 1, wherein the circuit arrangement further comprises:

at least one evaluation circuit which logs triggering operation of circuit elements of the circuit arrangement during an accident, said circuit elements being at least said dedicated triggers and said dedicated capacitors of said at least two current branches.

7. The circuit arrangement as claimed in claim 1, wherein the circuit arrangement further comprises:

a programmable microprocessor which controls at least a portion of the individual triggering switches of the at least two circuit branches and the at least one common triggering switch, the programmable microprocessor being operatively connected to the individual triggering switches of the at least two circuit branches and to the at least one common triggering switch.

8. The circuit arrangement as claimed in claim 7, wherein the circuit arrangement further comprises:

a plurality of further measuring points, potentials of the plurality of further measuring points being measured during operation of the vehicle, at least upon starting the engine; and

wherein

the microprocessor also checks the potentials of the plurality of further measuring points against predetermined values and displays any substantial variations therefrom.

9. The circuit arrangement as claimed in claim 1, wherein the circuit arrangement has at least one crash sensor and wherein during the accident respective capacitors deliver respective current impulses consecutively in time one immediately after the other, via respective triggers by means of respective individual triggering switches controlled by the at least one crash sensor, the at least one crash sensor being operatively connected to the respective individual triggering switches.

10. A circuit arrangement for triggering a vehicle passenger protection system in a vehicle having an engine, the triggering occurring during an accident involving the vehicle, comprising:

a voltage source operatively connected to a parallel circuit having at least two current branches;

current branches of said at least two current branches each having a dedicated trigger, a dedicated capacitor and a decoupling element connected in series, a dedicated trigger of a respective current branch of said at least two current branches activating said protection system in response to a current impulse supplied by a dedicated capacitor of said respective current branch of said at least two current branches during an accident, each dedicated capacitor having a predetermined capacitance and being charged with a predetermined ignition voltage;

said current branches of said at least two current branches each also having an individual triggering switch, a respective individual triggering switch of said respective current branch being connected across said respective dedicated trigger and said respective dedicated capacitor of said respective current branch;

at least one common triggering switch connected in series with said parallel circuit;

means for switching at least one of individual triggering switches of said at least two current branches and for switching said at least one common triggering switch from a non-conductive state to a conductive state, whereupon a capacitor in a current branch of said at least two current branches having the at least one of said individual triggering switches that has been switched into said conductive state discharges and supplies a current impulse to a dedicated trigger in said current branch having the at least one of said individual triggering switches that has been switched into said conductive state, said means for switching being responsive to the occurrence of the accident;

a plurality of measuring locations having potentials that are measured at least once upon a starting of the engine in the vehicle, current branches of said at least two current branches each having at least one measuring location of said plurality of measuring locations; and

test switching means for applying at least one test potential to defined switching points of the circuit arrangement in order to measure said potentials at said measuring locations.

11. The circuit arrangement as claimed in claim 10, wherein the circuit arrangement further comprises at least one evaluation circuit that records triggering operation of the individual triggering switches and the common triggering switch during the accident.

12. The circuit arrangement as claimed in claim 10, wherein said means for switching is a programmable microprocessor that is operatively connected to individual triggering switches of said at least two current branches and said at least one common triggering switch.

13. The circuit arrangement as claimed in claim 12, wherein the circuit arrangement further comprises a display, and wherein the programmable microprocessor checks the potentials of measuring locations of said plurality of measuring locations at least during the starting of the engine of the vehicle and displays on said display any deviations from predetermined potentials.

14. A circuit arrangement for triggering a vehicle passenger protection system in a vehicle having an engine, the triggering occurring during an accident involving the vehicle, comprising:

a voltage source operatively connected to a parallel circuit having at least two current branches;

a plurality of measuring locations;

current branches of said at least two current branches each having a dedicated trigger, a dedicated capacitor, at least one measuring location of said plurality of measuring locations and a decoupling element connected in series, a dedicated trigger of a respective current branch of said at least two current branches activating said protection system in response to a current impulse supplied by a dedicated capacitor of said respective current branch of said at least two current branches during an accident, each dedicated capacitor having a predetermined capacitance and being charged with a predetermined ignition voltage;

current branches of said at least two current branches each also having an individual triggering switch, a respective individual triggering switch of said respective current branch being connected across said respective dedicated trigger and said respective dedicated capacitor of said respective current branch;

at least one common triggering switch connected in series with said parallel circuit;

means for measuring potentials at said plurality of measuring locations at least upon starting of the engine;

means for switching at least one of individual triggering switches of said at least two current branches and for switching said at least one common triggering switch from a non-conductive state to a conductive state, whereupon a capacitor in a current branch of said at least two current branches having the at least one of said individual trigger switches that has been switched into said conductive state discharges and supplies a current impulse to a dedicated trigger in said current branch having the at least one of said individual triggering switches that has been switched into said conductive state, said means for switching being responsive to the occurrence of the accident.

15. The circuit arrangement as claimed in claim 14, wherein said circuit arrangement further comprises:

test switching means for applying at least one test potential to defined switching points of the circuit arrangement in order to measure said potentials at measuring locations of said plurality of measuring locations.

16. The circuit arrangement as claimed in claim 14, wherein the circuit arrangement further comprises at least one evaluation circuit that records triggering operation of the individual triggering switches and the common triggering switch during the accident.

17. The circuit arrangement as claimed in claim 14, wherein said means for switching is a programmable microprocessor that is operatively connected to individual triggering switches of said at least two current branches and said at least one common triggering switch.

18. The circuit arrangement as claimed in claim 17, wherein the circuit arrangement further comprises a display, and wherein the programmable microprocessor checks the potentials of measuring locations of said plurality of measuring locations at least during the starting of the engine of the vehicle and displays on said display any deviations from predetermined potentials.