HYDRAULIC ACCUMULATOR HEALTH MONITOR

• US 20140060030A1
• Filed: 06/03/2013
• Published: 03/06/2014
• Est. Priority Date: 08/31/2012
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Ma, Pengfei, Chen, Dayao, Peterson, Randal
• Application Number:
  US13/908,012
• Publication Number:
  US 20140060030A1
• Time in Patent Office: Days
• US Class Current: 60/413
• CPC Class Codes: E02F 9/123 Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: F15B 1/024 used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
• CPC Class Codes: F15B 1/033 with electrical control means
• CPC Class Codes: F15B 1/24 with rigid separating means, e.g. pistons
• CPC Class Codes: F15B 19/005 Fault detection or monitoring
• CPC Class Codes: F15B 2201/31 having rigid separating means, e.g. pistons
• CPC Class Codes: F15B 2201/505 Testing of accumulators, e.g. for testing tightness
• CPC Class Codes: F15B 2201/51 Pressure detection
• CPC Class Codes: F15B 2211/625 Accumulators
• CPC Class Codes: F15B 2211/6306 representing a pressure
• CPC Class Codes: F15B 2211/6653 Pressure control
• CPC Class Codes: F15B 2211/7058 Rotary output members
• CPC Class Codes: F15B 2211/855 Testing of fluid pressure systems
• CPC Class Codes: F15B 2211/857 Monitoring of fluid pressure systems
• CPC Class Codes: F15B 2211/87 Detection of failures

Abstract

A system and method to diagnose the operational health of a hydraulic accumulator are provided. The system can include a hydraulic accumulator selectively coupled to a hydraulic actuator, such as a swing motor. The accumulator can be charged by movement of the actuator. A pressure sensor can be associated with the accumulator to determine an accumulator pressure. A controller can be connected to the pressure sensor. The controller can determine a charge curve based on a relationship between an actuator operational parameter associated with the actuator movement and the accumulator pressure. The controller can compare the charge curve to a previously defined charge curve or range to determine an error between the charge curve and the previously defined charge curve or range. The degree of the error can be associated with the operational health of the accumulator, and if too large, the operator may be notified of the status.

Claims

1. A system to diagnose a health of a hydraulic accumulator, the system comprising:

a hydraulic actuator;

a hydraulic accumulator fluidly coupled to the hydraulic actuator, wherein the hydraulic accumulator is configured to be charged from movement of the actuator;

a pressure sensor associated with the hydraulic accumulator to determine an accumulator pressure; and

a controller in communication with the pressure sensor, the controller configured to;

determine a relationship between an actuator operational parameter associated with the movement of the actuator and the accumulator pressure; and

compare the relationship to a previously defined relationship to determine an error, if any, between the determined relationship and the previously defined relationship.

2. The system of claim 1, wherein the controller configured to:

determine a charge curve based on the relationship between the actuator operational parameter associated with a movement of the actuator and the accumulator pressure; and

compare the charge curve to a previously defined charge curve to determine an error between the charge curve and the previously defined charge curve.

3. The system of claim 1, wherein the actuator is a swing motor.

4. The system of claim 3, wherein the actuator operational parameter is a swing angular position.

5. The system of claim 3, wherein the actuator operational parameter is a swing angular speed.

6. The system of claim 1, wherein the controller is configured to notify an operator if the error is outside a predefined threshold range.

7. The system of claim 1, wherein the actuator is a hydraulic cylinder.

8. The system of claim 7, wherein the actuator operational parameter is a linear position of the hydraulic cylinder.

9. The system of claim 7, wherein the actuator operational parameter is a speed of the hydraulic cylinder.

10. The system of claim 1, wherein a valve is fluidly coupled between the actuator and the hydraulic accumulator for selective charging of the hydraulic accumulator.

11. A method of diagnosing an operational health of a hydraulic accumulator, the method comprising:

moving a hydraulic actuator to charge a hydraulic accumulator fluidly coupled to the actuator,

storing an accumulator pressure during the movement of the actuator;

determining a relationship between an actuator operational parameter associated with the movement of the actuator and the accumulator pressure; and

comparing the determined relationship to a previously defined relationship to determine an error, if any, between the determined relationship and the previously defined relationship.

12. The method of claim 11, further comprising:

determining a charge curve based on the relationship between the actuator operational parameter associated with a movement of the actuator and the accumulator pressure; and

comparing the charge curve to a previously defined charge curve to determine an error between the charge curve and the previously defined charge curve.

13. The method of claim 11, wherein the moving an actuator to a position step includes rotating a swing motor between a first position and a second position.

14. The method of claim 13, wherein the actuator operational parameter includes a swing angular position.

15. The method of claim 11, further including reducing the hydraulic accumulator to a minimum accumulator pressure prior to the moving step.

16. The method of claim 11, further including notifying an operator if the error is outside a predefined threshold range about the relationship.

17. The method of claim 11, wherein the moving an actuator to a position step includes moving a hydraulic cylinder between a first position and a second position.

18. The method of claim 17, wherein the actuator operational parameter includes a linear position.

19. A machine comprising:

a pump;

a hydraulic actuator selectively moved by fluid provided by the pump;

a hydraulic accumulator fluidly coupled to the hydraulic actuator, wherein the hydraulic accumulator is configured to be charged with pressurized fluid resulting from movement of the actuator;

a pressure sensor associated with the hydraulic accumulator to determine an accumulator pressure; and

a controller in communication with the pressure sensor, the controller configured to;

determine a relationship between an actuator operational parameter associated with the movement of the actuator and the accumulator pressure; and

compare the relationship to a previously defined relationship to determine an error, if any, between the determined relationship and the previously defined relationship.

20. The machine of claim 19, wherein the hydraulic actuator is a hydraulic swing motor, and the actuator operational parameter is a swing angular position.