Method to optimize alternator load capabilities

• US 20070200347A1
• Filed: 02/28/2006
• Published: 08/30/2007
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Sulzer, Bryan
• Granted Patent: US 7,479,707 B2
• Time in Patent Office: Days
• US Class Current: 290/40.C
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 7/1476 by mechanical action on the generator
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator

Abstract

A method of controlling an idle speed of an engine of a vehicle includes evaluating a plurality of instantaneous current requirements of the vehicle at respective points in time. The engine is a variably set to idle speeds based upon the evaluated instantaneous current requirement of the vehicle such that the idle speeds are above minimum engine idle speeds required to produce alternator output currents that satisfy the evaluated instantaneous current requirements of the vehicle.

Claims

1. A method of controlling an idle speed of an engine of a vehicle, comprising the steps of:

evaluating a plurality of instantaneous current requirements of the vehicle at respective points in time; and

variably setting the engine to idle speeds based upon the evaluated instantaneous current requirements of the vehicle such that the idle speeds are above minimum engine idle speeds required to produce alternator output currents that satisfy the evaluated instantaneous current requirements of the vehicle.

2. The method of claim 1 wherein said evaluating step includes estimating the instantaneous current requirements of the vehicle.

3. The method of claim 2 wherein the estimating includes identifying devices in the vehicle that will draw current.

4. The method of claim 3 wherein the estimating includes establishing a level of current draw for each of said devices.

5. The method of claim 1 wherein said evaluating step includes measuring the output current of an alternator.

6. The method of claim 1 wherein said evaluating step includes measuring a current draw of the vehicle.

7. The method of claim 1 wherein the engine is variably set to idle speeds such that the instantaneous current requirements are at least a predetermined percentage below current output capabilities at the idle speeds.

8. The method of claim 1 wherein the engine is variably set to idle speeds such that the idle speeds are at least a predetermined speed above the minimum engine idle speeds.

9. An idle speed control system for an engine of a vehicle, said system comprising:

an alternator configured to supply current to the vehicle;

an engine rotatingly coupled to said alternator;

at least one sensor configured to sense an instantaneous current requirement of the vehicle; and

a controller in communication with said at least one sensor, said controller being configured to set the engine to an idle speed at which a current output capability of said alternator is above the instantaneous current requirement and at which the current output capability of said alternator has a predetermined mathematical relationship to the instantaneous current requirement.

10. The system of claim 9 wherein said controller comprises a vehicle controller and an engine controller.

11. The system of claim 9 wherein said at least one sensor comprises a low impedance shunt receiving the alternator output current.

12. The system of claim 9 wherein said controller sets the engine idle speed by use of a lookup table.

13. The system of claim 9 wherein the predetermined mathematical relationship comprises the current output capability being a predetermined percentage above the instantaneous current requirement.

14. The system of claim 9 wherein the predetermined mathematical relationship comprises the current output capability being a predetermined amount above the instantaneous current requirement.

15. A method of controlling an idle speed of an engine of a vehicle, comprising the steps of:

sensing an instantaneous current requirement of the vehicle; and

setting the engine to an idle speed at which a current output capability of an alternator is above the instantaneous current requirement and at which the current output capability of said alternator has a predetermined mathematical relationship to the instantaneous current requirement.

16. The method of claim 15 wherein said sensing step includes measuring an output current of said alternator.

17. The method of claim 15 wherein said sensing step includes measuring a current draw of the vehicle.

18. The method of claim 15 wherein the predetermined mathematical relationship comprises the current output capability being a predetermined percentage above the instantaneous current requirement.

19. The method of claim 15 wherein the predetermined mathematical relationship comprises the current output capability being a predetermined amount above the instantaneous current requirement.

20. The method of claim 15 wherein the engine idle speed is set by use of a lookup table.