System and method of controlling airflow characteristics in an agricultural harvester

1. An agricultural harvesting system, comprising:

a chassis;

an agricultural product moving device coupled to said chassis;

an airflow system including a fan, said airflow system being coupled to said chassis;

a cleaning system coupled to said chassis, said cleaning system being configured to receive said agricultural product from said moving device, said cleaning system being further configured to receive an airflow from said airflow system; and

an airflow characterizing system coupled to said chassis, said airflow characterizing system being configured to measure an airflow profile across said cleaning system, said airflow characterizing system including a plurality of sensors positioned at spaced locations in said airflow that determine airflow by measuring a thermal transfer from said sensors to said airflow, said airflow characterizing system being configured to maintain a substantially constant electrical resistance of said sensors as said airflow varies.

2. The agricultural harvesting system of claim 1 , further comprising an airflow adjusting system configured to alter at least one characteristic of said airflow dependent upon said airflow profile measured by said airflow characterizing system.

3. The agricultural harvesting system of claim 2 , wherein said airflow adjusting system is further configured to at least one of divert air in the airflow, alter a speed of the fan, vary an inlet opening through which air of the airflow flows, vary an outlet though which the air flows, vary slat openings in a sieve, alter a speed of an auxiliary fan, alter a movement characteristic of the sieve, alter an opening of an air exhaust port, alter a ground speed of the harvesting system.

4. The agricultural harvesting system of claim 1 , wherein said sensors each include a thermistor.

5. The agricultural harvesting system of claim 4 , wherein said plurality of sensors are arranged in a grid.

6. The agricultural harvesting system of claim 5 , wherein said grid is generally arranged in a plane that is generally normal to a direction of the airflow.

7. The agricultural harvesting system of claim 6 , wherein said grid is proximate to said fan.

8. The agricultural harvesting system of claim 6 , wherein said cleaning system includes a sieve, said grid being supported by said sieve.

9. An airflow control system used in an agricultural harvesting system having a cleaning system, the airflow control system comprising:

an airflow generating system including a fan configured to generate an airflow, said airflow generating system being coupled to the harvester; and

an airflow characterizing system, said airflow characterizing system being configured to measure an airflow profile across the cleaning system, said airflow characterizing system including a plurality of sensors positioned at spaced locations in said airflow that determine airflow by measuring a thermal transfer from said sensors to said airflow, said airflow characterizing system being configured to maintain a substantially constant electrical resistance of said sensors as said airflow varies.

10. The airflow control system of claim 9 , wherein the airflow control system is configured to alter at least one characteristic of the airflow dependent upon said airflow profile measured by said airflow characterizing system.

11. The airflow control system of claim 10 , wherein the airflow control system is further configured to at least one of divert air in the airflow, alter a speed of the fan, vary an inlet opening through which air of the airflow flows, vary an outlet though which the air flows, vary slat openings in a sieve, alter a speed of an auxiliary fan, alter a movement characteristic of the sieve, alter an opening of an air exhaust port, alter a ground speed of the harvesting system.

12. The airflow control system of claim 9 , wherein said sensors each include a thermistor.

13. The airflow control system of claim 12 , wherein said plurality of sensors are arranged in a grid.

14. The airflow control system of claim 13 , wherein said grid is generally arranged in a plane that is generally normal to a direction of the airflow.

15. The airflow control system of claim 14 , wherein said grid is proximate to said fan.

16. The airflow control system of claim 15 , wherein said cleaning system includes a sieve, said grid being supported by said sieve.

17. A method of controlling airflow in a cleaning system of an agricultural harvesting system, the method comprising the steps of:

generating an airflow in the cleaning system; and

characterizing the airflow in the cleaning system with an airflow characterizing system by executing the steps of:

measuring portions of the airflow with a plurality of sensors positioned at spaced locations in said airflow, each of said sensors producing a signal representative of a thermal transfer from said sensor to said airflow;

maintaining a substantially constant electrical resistance of said sensors regardless of the amount of said airflow thereby holding a temperature of said sensors constant; and

creating an airflow profile across the cleaning system.

18. The method of claim 17 , further comprising the step of adjusting the airflow to alter at least one characteristic of the airflow dependent upon said airflow profile created by said airflow characterizing system.

19. The method of claim 18 , wherein the adjusting step includes at least one of:

diverting air in the airflow;

altering a speed of a fan;

varying an inlet opening through which air of the airflow flows;

varying an outlet though which the air flows;

varying slat openings in a sieve;

altering a speed of an auxiliary fan;

altering a movement characteristic of the sieve;

altering an opening of an air exhaust port; and

altering a ground speed of the agricultural harvesting system.

20. The method of claim 17 , wherein said sensors each include a thermistor.