Occupant classification system

1. A capacitance sensing apparatus comprising:

a sensor pad;

a sensing element disposed on the sensor pad;

at least one additional electronic element for detecting whether the seat is occupied; and

a switching mechanism for electrically connecting the at least one additional electronic element to the sensing element during capacitance measurements so that both the sensing element and the additional electronic element form a capacitive sensing electrode and for electrically disconnecting the at least one additional electronic element from the sensing element after the capacitance measurements.

2. The capacitance sensing apparatus according to claim 1 , wherein the at least one additional electronic element is a force sensitive sensor.

3. A capacitance sensing apparatus comprising:

a sensor pad;

a sensing element disposed on the sensor pad;

at least one additional electronic element for providing information related to another parameter; and

a switching mechanism for electrically connecting the at least one additional electronic element to the sensing element during capacitance measurements and for electrically disconnecting the at least one additional electronic element from the sensing element after the capacitance measurements;

wherein the sensing element functions as a heater element.

4. The capacitance sensing apparatus according to claim 1 , wherein wires connecting to the sensing element and the at least one additional electronic element to an electronic control unit are bundled together in a sensing harness, and wherein the sensing harness has a mechanical isolation wall for isolating the wires within the sensor harness from wires connected to the sensor pad not within the sensor harness.

5. The capacitance apparatus according to claim 4 , wherein the mechanical isolation wall is a spacer or thick-walled tubing.

6. An occupant classification system comprising:

a capacitance sensor comprising:

a sensor pad;

a sensing element disposed on the sensor pad;

an empty seat detector for determining whether the seat is occupied, wherein the empty seat detector includes an additional electronic element; and

a switching mechanism for electrically connecting the at least one additional electronic element to the sensing element during capacitance measurements and for electrically disconnecting the at least one additional electronic element from the sensing element after the capacitance measurements; and

an electronic control unit (ECU) in electrical communication with the sensing element and the at least one additional electronic element using a sensing harness, wherein the ECU is configured to send a time varying voltage to the sensing element and the additional electronic element and measure the sensed capacitance during the capacitance measurements, and configured to classify the occupant on a seat based on the sensed capacitance.

7. The occupant classification system according to claim 6 , wherein the ECU is configured for operating the switching mechanism.

8. The occupant classification system according to claim 6 , wherein the sensing element functions as a heater element, and wherein the ECU contains a temperature controller for controlling the heater element.

9. The occupant classification system according to claim 6 , wherein the sensing harness has a mechanical isolation wall for isolating the wires within the sensor harness from wires connected to the sensor pad not within the sensor harness.

10. The occupant classification system according to claim 9 , wherein the mechanical isolation wall is a spacer or thick-walled tubing.

11. An occupant sensing system for sensing an occupant of a vehicle seat comprising:

a capacitance sensor, wherein the capacitance sensor comprises:

a sensor pad;

a sensing element disposed on the sensor pad;

an empty seat detector for determining whether the seat is occupied, wherein the empty seat detector includes an additional electronic element; and

a switching mechanism for electrically connecting the additional electronic element to the sensing element during capacitance measurements and for electrically disconnecting the additional electronic element from the sensing element after the capacitance measurements; and

wherein the sensor pad, the additional element, and the switching mechanism are provided in the vehicle seat.

12. The occupant sensing system according to claim 11 , wherein the sensor pad is located within a seat bottom of the vehicle seat.

13. The occupant sensing system according to claim 11 , wherein the sensor pad is located within a seat back of the vehicle seat.

14. The occupant sensing system according to claim 11 , wherein the empty seat detector is located adjacent the sensor pad within a seat bottom of the vehicle seat.

15. The occupant sensing system according to claim 11 , wherein the empty seat detector is located adjacent to the sensor pad.

16. The occupant sensing system according to claim 11 , wherein the empty seat detector is disposed on the sensor pad.

17. The occupant sensing system according to claim 11 , wherein the sensor pad is disposed in one of a seat bottom and a seat back of the vehicle seat, and wherein the empty seat detector is disposed within the other of the seat bottom and the seat back.

18. The occupant classification system according to claim 11 , wherein the sensing element functions as a heater element, and further comprising a temperature controller for controlling the heater element.