Machine drive line overspeed protection method

• US 20070293366A1
• Filed: 06/19/2006
• Published: 12/20/2007
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Landes, James W.
• Granted Patent: US 7,556,585 B2
• Time in Patent Office: Days
• US Class Current: 477/34
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2710/1038 Output speed
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: F16H 2061/1244 Keeping the current state
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 2061/166 Preventing or initiating shifts for preventing stall or overspeed of engine
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A method of controlling driveshaft speed includes generating an overspeed protection action signal if an engine speed limit and a requested transmission gear ratio correspond to a driveshaft overspeed condition. An operating method for a machine includes disengaging a relatively higher transmission gear, and inhibiting re-engagement of the higher transmission gear responsive to an overspeed protection action signal. An electronic controller for the machine is configured to generate an overspeed protection action signal responsive to an engine speed limit and requested transmission gear ratio.

Claims

1. A method of controlling the speed of a driveshaft in a machine comprising the steps of:

receiving a requested transmission gear signal associated with a transmission gear ratio;

determining an engine speed limit;

determining if the engine speed limit and the transmission gear ratio correspond to a driveshaft overspeed condition; and

generating an overspeed protection action signal if the engine speed limit and the transmission gear ratio correspond to a driveshaft overspeed condition.

2. The method of claim 1 further comprising a step of limiting a driveshaft speed of the machine at least in part via a step of inhibiting operation of the machine in the transmission gear ratio responsive to the overspeed protection action signal.

3. The method of claim 2 wherein the step of limiting a driveshaft speed of the machine further comprises limiting a driveshaft speed of the machine via a step of controlling a machine ground speed, wherein the step of inhibiting operation of the machine in the transmission gear ratio comprises inhibiting operation in the transmission gear ratio responsive to a ground speed control fault condition.

4. The method of claim 3 wherein the step of controlling a machine ground speed comprises controlling engine fueling.

5. The method of claim 4 further comprising the steps of receiving broadcast ground speed signals, and determining a ground speed control fault condition if the broadcast ground speed signals differ from expected signals.

6. The method of claim 3 wherein the step of determining an engine speed limit includes a step of receiving a broadcast governed engine speed limit signal.

7. The method of claim 3 wherein the step of determining if the engine speed limit and the transmission gear ratio correspond to a driveshaft overspeed condition further comprises determining a predicted driveshaft speed associated with a governed engine speed limit and the transmission ratio, comparing the predicted driveshaft speed with a driveshaft speed limit, and determining a driveshaft overspeed condition exists if the predicted driveshaft speed is equal to or greater than the driveshaft speed limit, and the ground speed control fault condition exists.

8. The method of claim 7 wherein the step of generating an overspeed protection action signal comprises generating the signal where the predicted driveshaft speed is above a speed associated with a resonance vibration of the driveshaft.

10. The method of claim 8 further comprising a step of limiting a driveshaft speed of the machine to a selected speed range at least in part via the inhibiting step.

11. The method of claim 10 wherein the inhibiting step further comprises inhibiting re-engaging the relatively higher transmission gear responsive to an overspeed protection action signal that is based at least in part on the engine speed limit, the gear ratio associated with the relatively higher transmission gear and a ground speed control fault condition.

9. A method of operating a machine comprising the steps of:

operating the machine in a relatively higher transmission gear;

operating the machine in a relatively lower transmission gear, including disengaging the relatively higher transmission gear;

receiving a request to re-engage the relatively higher transmission gear;

determining an engine speed limit; and

inhibiting re-engaging the relatively higher transmission gear responsive to an overspeed protection action signal that is based at least in part on the engine speed limit and a gear ratio associated with the relatively higher transmission gear.

12. The method of claim 111 further comprising the steps of periodically receiving a machine ground speed signal with an electronic controller, and determining a ground speed control fault condition based at least in part on a ground speed signal failure.

13. The method of claim 12 wherein:

the step of determining an engine speed limit comprises periodically receiving with a transmission controller a broadcast governed engine speed signal from an engine controller;

the step of receiving a request to re-engage the relatively higher transmission gear comprises receiving with the transmission controller a requested transmission gear signal from an operator input device;

the method further comprising the steps of determining if a ground speed control fault condition exists, and generating a driveshaft protection action signal responsive to the governed engine speed signal and the requested transmission gear signal where the ground speed control fault condition exists.

14. A machine comprising:

an engine;

a driveshaft;

a transmission coupled with each of said engine and said driveshaft;

an operator input device configured to output a requested transmission gear signal associated with a gear ratio of said transmission; and

at least one electronic controller coupled with said transmission and with said operator input device, said at least one electronic controller being configured via an overspeed protection control algorithm to generate an overspeed protection action signal responsive to the requested transmission gear signal and an engine speed limit, if the gear ratio associated with the requested transmission gear and an engine speed limit correspond to a driveshaft overspeed condition.

15. The machine of claim 14 wherein said overspeed protection action signal comprises an inhibition signal associated with a transmission gear.

16. The machine of claim 15 wherein said at least one electronic controller is configured to control a ground speed of said machine, and further configured to generate said inhibition signal responsive to a ground speed control fault condition.

17. The machine of claim 16 wherein said at least one electronic controller includes an engine controller operably coupled with said engine and configured to control machine ground speed, and a transmission controller operably coupled with said transmission, said transmission controller being configured to receive a machine ground speed signal from said engine controller and to determine said ground speed control fault condition responsive to a ground speed signal failure.

18. The machine of claim 16 wherein said transmission further comprises at least two gears, including a high gear, and an electro-hydraulic control valve configured to control an engagement of said high gear, said transmission controller further being configured to selectively disable said electro-hydraulic control valve responsive to said inhibition signal.