Vehicle occupant detection system

• US 7,205,902 B2
• Filed: 11/26/2004
• Issued: 04/17/2007
• Est. Priority Date: 01/16/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kiribayashi, Shinichi
• Primary Examiner(s): Pope; Daryl C
• Application Number:
  US10/996,438
• Publication Number:
  US 20050156467A1
• Time in Patent Office: 872 Days
• Field of Search: 340/667, 340/665, 340/666, 340/573.1, 340/635, 340/636.12, 340/657, 340/660, 307/10.1
• US Class Current: 340/667
• CPC Class Codes: B60R 2021/01197 Warning devices
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges

Abstract

In an occupant detection system, a determination section of an occupant detection ECU determines occupancy status of the seat based on loads applied to the seat. A power supply section of the ECU provides a power supply voltage lower than a battery voltage of the vehicle to load sensors and the determination section. A resistor is connected in a sensor power supply line that connects the load sensors with the power supply section. A zener diode is connected between the resistor and the power supply section through branch connection. A resistance of the resistor is predetermined so that the resistor becomes open when a short occurs and does not affect to dynamic ranges of the load sensors. A breakdown voltage of the zener diode is predetermined between the power supply voltage and a guaranteed voltage of the ECU.

Claims

1. An occupant detection system comprising:

a load sensor that measures a load applied to a seat of a vehicle; and

an electronic control unit having a determination section that determines occupancy status of the seat based on a result of the load measurement, a power supply section that supplies power to the load sensor and the determination section with a power supply voltage lower than a battery voltage of the vehicle, and a communication section that sends a result of the occupancy status determination to an external device, wherein,

the load sensor and the power supply section are electrically connected with each other via a sensor power supply line in which a resistor having a specific resistance is connected,

the specific resistance is predetermined so that the resistor becomes open when a short occurs and does not affect to a dynamic range of the load sensor,

the power supply section and the resistor are electrically connected with each other via an internal power supply line to which a zener diode having a specific breakdown voltage is connected through branch connection, and

the specific breakdown voltage is predetermined between the power supply voltage and a guaranteed voltage of the electronic control unit.

2. The occupant detection system according to claim 1, wherein the electronic control unit is arranged under the seat.

3. The occupant detection system according to claim 1, wherein:

the electronic control unit further includes a warning transmission section that is electrically connected to an external warning device that provides a warning to a user; and

the warning transmission section sends a warning signal indicating an open of the resistor to the external warning device when the resistor becomes open.

4. The occupant detection system according to claim 1, wherein the communication section is electrically connected to an external warning device that provides a warning to a user for sending a warning signal indicating an open of the resistor to the external warning device when the resistor becomes open.

5. The occupant detection system according to claim 4, wherein the external warning device is a display included in a vehicle navigation system.

6. The occupant detection system according to claim 1, wherein the external device is a passive safety system.

7. The occupant detection system according to claim 6, wherein the external warning device is a display included in a vehicle navigation system.