Wet seat protection for air bag control occupant detection

• US 6,696,948 B2
• Filed: 11/02/2001
• Issued: 02/24/2004
• Est. Priority Date: 11/02/2001
• Status: Expired due to Fees

• Current Assignee: Nidec Elesys Americas Corporation (Nidec Corporation)
• Original Assignee: Elesys North America Incorporated (Nidec Corporation)
• Inventors: Shieh, Shiuh-An, Thompson, Gregory T., Rittmueller, Philip
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): NGUYEN, HUNG T
• Application Number:
  US10/033,585
• Publication Number:
  US 20030090376A1
• Time in Patent Office: 844 Days
• Field of Search: 340/561, 340/562, 340/438, 340/567, 340/425.5, 340/433, 340/426, 280/735, 280/728.1, 180/271, 180/273, 180/274, 701/49, 701/45
• US Class Current: 340/561
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/0025 by using weight measurement
• CPC Class Codes: B60N 2210/12 Capacitive; Electric field
• CPC Class Codes: B60N 2220/20 using a deterministic algorithm
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors

Abstract

A passenger detection system is provided. The passenger detection system utilizes an oscillation circuit that causes an antenna electrode to emit an electric field that is disrupted by the electrical characteristics of an object placed on the seat. This disruption alters the current and phase of the signal in the antenna electrode. By comparing the current flowing in the antenna electrode and/or the difference between the phase of the signal in the antenna electrode and the oscillation circuit output signal with predetermined threshold values, it is possible to detect the presence of a passenger in a reliable and inexpensive manner. Environmental sensors are used to make the determination more accurate. Humidity, moisture and/or grounding condition are detected and used to alter processing, values or calculations.

Claims

1. A vehicle passenger detection system for sensing an occupant in a seating area, the system comprising:

a passenger detection system; and

a moisture sensor connected with the passenger detection system;

wherein a measured value of the passenger detection system is altered as a function of a resistance where the function comprises an X^Y function where Y is a fraction.

2. The system of claim 1 wherein X comprises the resistance.

3. The system of claim 1 wherein Y is ½

.

4. The system of claim 1 wherein Y is ⅓

.

5. The system of claim 1 wherein the passenger detection system comprises a capacitive sensing system.

6. The system of claim 1 wherein the moisture sensor comprises two conductors connected by absorbent material.

7. The system of claim 1 wherein the moisture sensor is positioned in a seat.

8. The system of claim 1 wherein the passenger detection system operatively connects with an air bag control system.

9. The system of claim 1 wherein the measured value is multiplied by the resistance divided by a constant, the resistance divided by the constant comprising X.

18. The system of claim 1 further comprising a moisture resistant cover adjacent the passenger detection system.

10. A vehicle passenger detection method for sensing an occupant in a seating area, the method comprising the acts of:

(a) measuring moisture;

(b) determining a presence of the passenger in the passenger seating area;

(c) altering a measured value of (b) as a function of the moisture where the function comprises an X^Y function where Y is a fraction.

11. The method of claim 10 wherein (b) comprises determining the presence with a capacitive sensing system.

12. The method of claim 10 wherein (a) comprises measuring a resistance.

13. The method of claim 10 wherein (a) comprises measuring with a sensor positioned in a seat and wherein a second sensor for (b) is also in the seat.

14. The method of claim 10 further comprising:

(d) controlling an air bag system in response to (b).

15. The method of claim 10 wherein (c) comprises multiplying the measured value by a resistance divided by a constant, the resistance divided by the constant comprising X.

16. The method of claim 10 wherein X^Y comprises a square root.

17. The method of claim 10 wherein X^Y comprises a cube root.