Grade speed control and method for railway freight vehicle

• US 6,353,780 B1
• Filed: 06/28/2000
• Issued: 03/05/2002
• Est. Priority Date: 06/29/1999
• Status: Expired due to Fees

• Current Assignee: Westinghouse Air Brake Technologies Corporation
• Original Assignee: Westinghouse Air Brake Technologies Corporation
• Inventors: Hart, James E.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US09/605,614
• Time in Patent Office: 615 Days
• Field of Search: 701/20, 701/19, 701/51, 701/93, 701/96, 246/182.A, 246/182.B, 246/182.C, 246/182.R, 303/15, 303/43, 303/7, 303/3, 303/69
• US Class Current: 701/20
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60T 13/665 the systems being specially adapted for transferring two or more command signals, e.g. railway systems B60T13/662 takes precedence
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 7/126 Brakes for railway vehicles coming into operation in case of exceeding a predetermined speed self-acting brakes in general F16D59/00
• CPC Class Codes: B60T 8/1705 for rail vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A grade speed control system and method for a railway freight vehicle can include a microprocessor receiving input from, for example, the dynamic and independent brakes on the locomotive, and the brakes on each rail car. The microprocessor can store values for desired train speed and actual train speed as well as constants and equations for converting raw data to derive brake cylinder pressure adjustments for implementing train speed control functions. The grade speed control system can also include communicate with brake cylinder control devices on articulated rail cars to increase or decrease the brake cylinder pressures to control the train speed. If actual speed differs from target speed by more than a predetermined amount, a target acceleration can be calculated and brake cylinder pressures adjustments can be derived to achieve the target acceleration to bring the actual speed of the train to the target speed in a reasonably brief time period. This sequence can be reiterated as the train progresses down the grade, automatically adjusting train braking effort as required to maintain the target speed within a tight range.

Claims

1. A grade speed control method for a railway freight train having a locomotive and at least one unpowered articulated rail car having an electro-pneumatic (ECP) brake control system including a fluid pressure activated brake cylinder device and a graduated release valve, the method comprising:

a. selecting a target train velocity for negotiating a down grade;

b. monitoring actual train velocity on said down grade;

c. detecting a velocity difference between the target velocity and the actual velocity; and

d. adjusting brake cylinder pressure to vary friction retardation on said at least one unpowered articulated rail car responsive to said velocity difference to cause the actual velocity to generally correspond to the target velocity.

2. The method of claim 1 further comprising reiteratively carrying out steps c through d.

3. The method of claim 2 further comprising:

a. selecting a new target velocity; and

b. adjusting the brake cylinder pressure to cause the actual velocity to generally correspond to the new target velocity.

4. The method of claim 1 wherein said adjusting brake cylinder pressure is responsive to a velocity difference exceeding a predetermined minimum velocity difference.

5. A grade speed control method for a railway freight train having a locomotive and at least one articulated rail car having an ECP brake control system including a fluid pressure activated brake cylinder device and a graduated release valve, the method comprising:

a. monitoring actual train velocity;

b. selecting a target train velocity;

c. detecting a velocity difference between the target velocity and the actual velocity;

d. calculating a prevailing acceleration of the train;

e. calculating a target acceleration;

f. deriving a brake cylinder pressure adjustment to achieve the target acceleration; and

g. implementing said brake cylinder adjustment to cause the prevailing acceleration to generally correspond to the target acceleration to bring the actual velocity to the target velocity.

6. A grade speed control method for a railway freight train having a locomotive and at least one articulated rail car having an electro-pneumatic (ECP) brake control system including a fluid pressure activated brake cylinder device and a graduated release valve, the method comprising:

a. monitoring actual train velocity;

b. selecting a target train velocity;

c. detecting a velocity difference between the target velocity and the actual velocity;

d. adjusting brake cylinder pressure on said at least one articulated rail car responsive to said velocity difference to cause the actual velocity to generally correspond to the target velocity;

e. determining whether the velocity difference exceeds a predetermined amount;

f. determining whether the prevailing acceleration is positive or negative;

g. deriving a first brake cylinder pressure adjustment based upon a higher level of desired braking force;

h. deriving a second brake cylinder pressure adjustment based upon a lower level of desired braking force;

i. implementing said first brake cylinder pressure adjustment responsive to at least one of the velocity difference exceeding the predetermined amount and the prevailing acceleration being positive; and

j. implementing said second brake cylinder pressure adjustment responsive to at least one of the velocity difference being less than the predetermined amount and the prevailing acceleration being negative.

7. The method of claim 6 further comprising providing a speed warning responsive to at least one of the velocity difference exceeding the predetermined amount and the prevailing acceleration being positive.

8. The method of claim 6 further comprising reiteratively calculating said prevailing acceleration over a shorter time interval responsive to implementing said first brake cylinder pressure adjustment.

9. The method of claim 6 further comprising reiteratively calculating said prevailing acceleration over a time interval calculated as a function of said second brake cylinder pressure adjustment.

10. A grade speed control method for a railway freight train having a locomotive and at least one articulated rail car having an electro-pneumatic (ECP) brake control system including a fluid pressure activated brake cylinder device and a graduated release valve, the method comprising:

a. monitoring actual train velocity;

b. selecting a target train velocity;

c. detecting a velocity difference between the target velocity and the actual velocity;

d. adjusting brake cylinder pressure on said at least one articulated rail car responsive to said velocity difference to cause the actual velocity to generally correspond to the target velocity;

e. detecting whether a brake cylinder pressure adjustment would result in a brake cylinder pressure exceeding one-half of a full service brake cylinder pressure; and

f. providing a warning responsive to said detecting a brate cylinder pressure exceeding one-half of a full service brake cylinder pressure.

11. A grade speed control method for a railway freight train having a locomotive and at least one articulated rail car having an electro-pneumatic (ECP) brake control system including a fluid pressure activated brake cylinder device and a graduated release valve, the method comprising:

a. monitoring actual train velocity;

b. selecting a target train velocity;

c. detecting a velocity difference between the target velocity and the actual velocity;

d. adjusting brake cylinder pressure on said at least one articulated rail car responsive to said velocity difference to cause the actual velocity to generally correspond to the target velocity;

e. detecting whether a brake cylinder pressure adjustment would result in a reduction of brake cylinder pressure by more than a predetermined amount; and

f. substituting a predetermined maximum brake cylinder pressure reduction responsive to said detecting a reduction of brake cylinder pressure by more than a predetermined amount.

12. A grade speed control method for a railway freight train having a locomotive, multiple unpowered rail cars, an electropneumatic brake control system having graduated brake capability and including fluid pressure activated brake cylinders on each of said multiple unpowered rail cars, the method comprising:

a. selecting a target train velocity for negotiating a down grade;

b. monitoring actual train velocity on said down grade;

c. detecting a velocity difference between the target velocity and the actual velocity; and

d. adjusting brake cylinder pressure to vary friction retardation on said multiple unpowered rail cars responsive to said velocity difference to cause the actual velocity to generally correspond to the target velocity.

13. The method of claim 12 further comprising:

a. detecting whether a brake cylinder pressure adjustment would result in a brake cylinder pressure exceeding a predetermined brake cylinder pressure; and

b. providing a warning responsive to said detecting.

14. An apparatus on a railway freight train for controlling the speed of the train on a down grade, said freight train having a locomotive, multiple unpowered rail cars, an electropneumatic brake control system having graduated brake capability and including fluid pressure activated brake cylinders on each of said multiple unpowered rail cars, the apparatus comprising:

a. train engineer controls for selecting and inputting a target train velocity for negotiating a down grade;

b. train speed sensors to monitor actual train velocity on said down grade;

c. a grade speed controller receiving input from said train engineer controls and said train speed sensors, said grade speed controller operatively associated with said electropneumatic brake control system on said multiple unpowered rail cars for controlling pressure in said fluid pressure activated brake cylinders;

d. said grade speed controller comparing said target velocity and said actual velocity to detect a velocity difference therebetween; and

e. said grade speed controller adjusting brake cylinder pressure to vary friction retardation on said multiple unpowered rail cars responsive to detecting a velocity difference to cause said actual velocity to generally correspond to said target velocity.

15. The apparatus of claim 14 further comprising:

a. said grade speed controller calculating a prevailing acceleration of the train based upon reiterative velocity readings;

b. said grade speed controller calculating a target acceleration based upon said velocity difference;

c. said grade speed controller deriving a brake cylinder pressure adjustment to achieve said target acceleration; and

d. said grade speed controller implementing said brake cylinder adjustment to cause said prevailing acceleration to generally correspond to said target acceleration to bring the actual velocity to the target velocity.

16. The apparatus of claim 14 wherein said grade speed controller adjusts brake cylinder pressure is responsive to said velocity difference exceeding a predetermined minimum velocity difference.

17. The apparatus of claim 14 further comprising said grade speed controller:

a. determining whether the velocity difference exceeds a predetermined amount;

b. determining whether the prevailing acceleration is positive or negative;

c. deriving a first brake cylinder pressure adjustment based upon a higher level of desired braking force;

d. deriving a second brake cylinder pressure adjustment based upon a lower level of desired braking force;

e. implementing said first brake cylinder pressure adjustment responsive to at least one of the velocity difference exceeding the predetermined amount and the prevailing acceleration being positive; and

f. implementing said second brake cylinder pressure adjustment responsive to at least one of the velocity difference being less than the predetermined amount and the prevailing acceleration being negative.

18. The apparatus of claim 17 further comprising said grade speed controller providing a speed warning responsive to at least one of the velocity difference exceeding the predetermined amount and the prevailing acceleration being positive.

19. The apparatus of claim 17 further comprising said grade speed controller reiteratively calculating said prevailing acceleration over a shorter time interval responsive to implementing said first brake cylinder pressure adjustment.

20. The apparatus of claim 17 further comprising said grade speed controller reiteratively calculating said prevailing acceleration over a time interval calculated as a function of said second brake cylinder pressure adjustment.

21. The apparatus of claim 17 further comprising said grade speed controller:

a. detecting whether a brake cylinder pressure adjustment would result in a brake cylinder pressure exceeding a predetermined brake cylinder pressure; and

b. providing a warning responsive to said detecting.

22. The apparatus of claim 17 further comprising said grade speed controller:

a. detecting whether a brake cylinder pressure adjustment would result in a reduction of brake cylinder pressure by more than a predetermined amount; and

b. substituting a predetermined maximum brake cylinder pressure reduction responsive to said detecting.