COOLING FAN CONTROL

• US 20110132292A1
• Filed: 04/23/2010
• Published: 06/09/2011
• Est. Priority Date: 04/23/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Parks, Steven James, O'Donohue, Garrett, Karanth, Dinakara, Gale, Allan Roy, Schwartz, William Samuel
• Granted Patent: US 8,104,435 B2
• Time in Patent Office: Days
• US Class Current: 123/41.12
• CPC Class Codes: F01P 7/046 using mechanical drives
• CPC Class Codes: F01P 7/048 using electrical drives

Abstract

Methods and systems are provided for reducing aerodynamic drag on a moving vehicle. One example method comprises, during a first vehicle moving condition, operating the cooling fan, and during a second vehicle moving condition, selectively applying a braking torque on the fan.

Claims

1. A method of controlling a cooling fan of a vehicle cooling system, comprising:

during a first vehicle moving condition, operating the cooling fan; and

during a second vehicle moving condition, selectively applying a braking torque on the fan.

2. The method of claim 1, wherein the first vehicle moving condition includes when an engine temperature is above a threshold temperature.

3. The method of claim 1, wherein operating the cooling fan includes powering cooling fan rotation from engine rotational output.

4. The method of claim 1, wherein the cooling fan is an electric fan and operating the cooling fan includes enabling an electric motor coupled to the cooling fan.

5. The method of claim 1, wherein the second vehicle moving condition includes the fan free-wheeling.

6. The method of claim 5, wherein the second vehicle moving condition further includes a vehicle engine being deactivated.

7. The method of claim 1, wherein applying a braking torque includes applying a mechanical braking torque or an electrical braking torque in response to operating conditions.

8. The method of claim 7, wherein the operating conditions include at least one of engine temperature, coolant temperature, engine speed, vehicle speed, and engine output, and wherein applying a braking torque in response to operating conditions includes, increasing a braking torque as the vehicle speed increases, increasing a braking torque as the engine output increases, and decreasing braking torque as the engine temperature or coolant temperature increases.

10. The method of claim 7, wherein applying a mechanical braking torque includes engaging a latch or pin to rotating fan blades.

11. The method of claim 7, wherein applying an electrical braking torque includes shorting a circuit of an electric motor coupled to the fan.

12. The method of claim 1, further comprising, during a third vehicle moving condition, with the fan free-wheeling,

operating an electric motor coupled to the fan to generate electrical energy from a braking of fan rotation;

and

charging a system battery with the generated energy.

13. The method of claim 2, wherein applying a braking torque includes applying the braking torque when vehicle speed is above a threshold speed and engine temperature is below the threshold temperature.

9. (canceled)

14. A method of reducing aerodynamic drag on a vehicle, comprising,

during vehicle motion,

enabling a cooling fan of a vehicle cooling system when airflow assistance is desired;

disabling the cooling fan of the vehicle cooling system when airflow assistance is not desired; and

with the cooling fan disabled, selectively applying a braking torque on a free wheeling cooling fan.

15. The method of claim 14, wherein enabling the fan includes powering cooling fan rotation from engine rotational output or enabling an electric motor coupled to the fan, and wherein disabling the fan includes uncoupling the fan from the engine or disabling the electric motor.

16. The method of claim 14, wherein applying a braking torque includes applying a mechanical braking torque by engaging a latch or pin to the free-wheeling fan, the braking torque increased as a vehicle speed and/or engine output increases, the braking torque decreased as an engine temperature and/or coolant temperature increases.

17. The method of claim 15, wherein applying a braking torque includes applying an electrical braking torque by shorting a circuit of the electric motor to use the generated back EMF while free-wheeling to stop fan rotation, the braking torque increased as a vehicle speed and/or engine output increases above a threshold, the braking torque decreased as an engine temperature and/or coolant temperature increases above a threshold.

18. The method of claim 14, further comprising selectively applying the braking torque based on vehicle operating conditions.

19. A vehicle cooling system configured to cool vehicle under-hood components including,

a cooling fan;

and

a controller having instructions stored thereon executable to,

during a first vehicle moving condition, when airflow assistance is desired, operate the cooling fan;

during a second vehicle moving condition, when airflow assistance is not desired and the fan is free-wheeling, selectively apply a braking torque on the rotating fan.

20. The system of claim 19, wherein applying a braking torque includes applying one of a mechanical braking torque and an electrical braking torque, and adjusting an amount of braking torque applied based on vehicle operating conditions.

21. The system of claim 19, wherein during a third vehicle moving condition, where the fan is free-wheeling and a braking torque is applied, the controller is further configured to operate an electric motor coupled to the fan to generate electrical energy from the braking of fan rotation and charge a system battery with the generated energy.