Device for the control of an active element of an occupant retention system in a vehicle

• US 20040045760A1
• Filed: 09/29/2003
• Published: 03/11/2004
• Est. Priority Date: 06/05/2000
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Baumgartner, Walter, Brauner, Norbert, Foell, Albrecht
• Granted Patent: US 7,121,376 B2
• Time in Patent Office: Days
• US Class Current: 180/282
• CPC Class Codes: B60R 2021/01027 Safing sensors
• CPC Class Codes: B60R 2021/01184 Fault detection or diagnostic circuits in power circuits B60R2021/01129
• CPC Class Codes: B60R 2021/01306 monitoring vehicle inclination
• CPC Class Codes: B60R 2021/01325 Vertical acceleration
• CPC Class Codes: B60R 2021/01327 Angular velocity or angular acceleration
• 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 21/017 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

In order to produce a safing concept, an extra-safing-sensor in the control unit (ECU) is foregone and the sating function from one of the available acceleration or turn-rate sensors (S1 to S5) is replaced. Furthermore a pre-stage is connected to the firing element (Z1, Z2), before the existing firing path, which, depending upon the sensor signals as analysed by the controller unit (1), controls a safety switch (T11), in series with the firing switches and the firing element.

Claims

1. A device for driving an active element (Z1, Z2) of an occupant restraint system of a vehicle having

a control unit (1),

sensors (S1 to S2), whose signals are fed to the control unit (1),

an ignition path (C1, T15, Z1, T16;

C2, T21, T25, Z2, T26), which has an energy store (C1, C2) a safety switch (T11), an active element (Z1, Z2) and at least one ignition switch (T15, T16, T25, T26), which is controlled by the control unit,

a prestage (R1, T12, T13;

R2, T22, T23) which drives the safety switch (T11, T21) and is controlled by the control unit, the prestage enabling the safety switch (T11, T21) if at least two sensors (S1, S2;

S3, S4, S5) identify a sufficient acceleration, and the prestage inhibiting the safety switch if a sensor and/or the control unit (1) is defective.

2. The device as claimed in claim 1, characterized in that one of the sensors is designed as an early crash sensor (S1) and one of the sensors is designed as an acceleration sensor (S2) with detection in the x direction.

3. The device as claimed in one of the preceding claims, characterized in that the prestage enables the safety switch (T11, T21) if at least three sensors (S1, S2;

S3, S4, S5) identify a sufficient acceleration.

4. The device as claimed in one of the preceding claims, characterized in that one of the sensors is designed as an early crash sensor (S1), one of the sensors is designed as an acceleration sensor (S3) with detection in the z direction and one of the sensors is designed as an acceleration sensor (S3) with detection in the y direction.

5. The device as claimed in one of the preceding claims, characterized in that the prestage has a prestage switch (T11, T12, T21, T22), whose input (B11;

B12, B21, B22) is connected to the control unit and whose through-connection branch is connected to the input of the safety switch (T11, T21).

6. The device as claimed in one of the preceding claims, characterized

in that the prestage has a plurality of prestage switches whose inputs are connected to the control unit (1) and whose through-connection branches are connected in series,

in that a resistor is connected in series with the through-connection branches, and

in that the safety transistor turns on when the prestage switches are enabled by the control unit.

7. The device as claimed in one of the preceding claims, characterized in that, in the event of a short circuit between two inputs of the prestage switches, the resulting potential is in proximity to ground (GND) or the supply voltage (Vcc) to such an extent that at least one of the prestage switches (T12, T13;

T22, T23) turns off.

8. The device as claimed in one of claims 1 to 6, characterized in that the safety switch (T21, T11) is inhibited in the event of a disturbance acting in the same sense or a short circuit between two inputs of the prestage switches.

9. The device as claimed in one of the preceding claims, characterized in that the control unit (1) is subdivided into the following separate units:

the main control unit (2), which drives the ignition switch/switches (T15, T16, T25, T26),

the safety control unit (3), which controls the safety switch via the prestage, the main control unit (2) and the safety control unit preferably being designed in each case as microcontrollers and in each case evaluating the signals of the sensors.

11. The device as claimed in one of the preceding claims, characterized in that the control unit (1) is essentially designed as a microcontroller (μ

C;

     1).

12. The device as claimed in one of the preceding claims, characterized in that the prestage switch/switches, the ignition switch/switches, the safety switch/switches are preferably designed as bipolar and/or as field-effect transistors.

13. The device as claimed in one of the preceding claims, characterized in that the prestage comprises prestage switches of discrete construction.

10. A device for driving an active element of an occupant restraint system, characterized in that a first sensor (S1) serves as a safing sensor and is designed as an early crash sensor and/or as an acceleration sensor at least partly in the x direction.