METHODS AND SYSTEM FOR DIAGNOSING AN ENGINE COMPONENT BASED ON AN ENGINE SPEED PROFILE DURING AN ENGINE SHUTDOWN EVENT

• US 20180080404A1
• Filed: 09/16/2016
• Published: 03/22/2018
• Est. Priority Date: 09/16/2016
• Status: Active Grant

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: General Electric Company
• Inventors: NAIR, Shailesh, OTTIKKUTTI, Pradheepram
• Granted Patent: US 10,202,926 B2
• Time in Patent Office: Days
• CPC Class Codes: F02B 77/08 Safety, indicating, or supervising devices thermal insulation F02B77/11; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 2200/1012 Engine speed gradient
• CPC Class Codes: F02D 41/0097 using means for generating speed signals
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: G01P 21/02 of speedometers
• CPC Class Codes: G01P 3/481 of pulse signals

Abstract

Various methods and systems are provided for diagnosing an engine component based on a measured engine speed during an engine shutdown event. As one embodiment, a method for an engine includes measuring an engine speed drop rate, via an engine speed sensor, during an engine shutdown event; and indicating a change in performance of one of the engine speed sensor or an additional engine component in response to the measured engine speed drop rate deviating from a reference engine speed drop rate by a pre-set or pre-defined threshold rate.

Claims

1. A method for an engine, comprising:

measuring an engine speed drop rate, via an engine speed sensor, during an engine shutdown event; and

indicating a change in performance of one of the engine speed sensor or an additional engine component in response to the measured engine speed drop rate deviating from a reference engine speed drop rate by a threshold rate.

2. The method of claim 1, wherein the reference engine speed drop rate is determined based on an expected engine speed profile during the engine shutdown event stored in a memory of a controller of the engine and further comprising, updating the stored engine speed profile based on the measured engine speed drop rate.

3. The method of claim 2, further comprising building a friction profile of the engine over time based on changes to the stored engine speed profile and monitoring changes in the friction profile.

4. The method of claim 3, further comprising adjusting an engine operating parameter during engine operation following the engine shutdown event, based on the changes in the friction profile, to maintain a desired engine speed.

5. The method of claim 3, further comprising indicating the change in performance of the additional engine component in response to the friction profile changing by greater than a threshold friction amount.

6. The method of claim 5, wherein indicating the change in performance of the additional engine component includes:

indicating one or more of wear to an engine valve, degradation of a piston liner, or degradation of a piston ring in response to the friction profile decreasing by at least the threshold amount; and

indicating one or more of increased soot buildup on a rotating component of the engine, reduced lubrication to the rotating component, or degraded crankshaft bearings, in response to the friction profile increasing by at least the threshold amount.

7. The method of claim 1, wherein the engine speed sensor is a first crankshaft speed sensor and further comprising indicating the change in performance of the first crankshaft speed sensor in response to the measured engine speed drop rate deviating from the reference engine speed drop rate by the threshold rate and an engine speed drop rate measured by a second crankshaft speed sensor during the engine shutdown event not deviating from the reference engine speed drop rate by the threshold rate.

8. The method of claim 1, further comprising indicating the change in performance of the engine speed sensor in response to the measured engine speed drop rate deviating from the reference engine speed drop rate by the threshold rate and no additional diagnostic code being set in a controller of the engine indicating the change in performance of the additional engine component.

9. The method of claim 1, wherein measuring the engine speed drop rate via the engine speed sensor during the engine shutdown event occurs between a first time after engine shutdown when fueling to the engine is below a threshold fueling rate and an oil temperature of the engine is above a threshold oil temperature and a second time after engine shutdown when the engine speed decreases to a lower threshold engine speed.

10. The method of claim 9, wherein the first time includes after a final fuel injection into a last cylinder of the engine and further comprising, adjusting a fuel injection amount of the final fuel injection to adjust engine speed to a starting engine speed for measuring the engine speed drop rate during the engine shutdown event.

11. The method of claim 9, wherein the first time includes after a final fuel injection into a last cylinder of the engine and further comprising adjusting the measured engine speed drop rate based on a final engine speed during the final fuel injection.

12. The method of claim 1, further comprising initiating the engine shutdown event in response to the engine idling and a request to update an engine speed profile or friction profile of the engine during select engine operating conditions, where the engine speed profile and friction profile are updated based on the measured engine speed drop rate during the engine shutdown event.

13. A method for an engine, comprising:

tracking changes in a measured drop rate in engine speed output by a crankshaft sensor during an engine shutdown event over a plurality of engine shutdown events;

determining a friction profile of the engine based on the tracked changes in the measured drop rate in engine speed; and

adjusting engine operation based on changes to the friction profile.

14. The method of claim 13, wherein adjusting engine operation based on the changes to the friction profile includes adjusting a fuel value of the engine during subsequent engine operation to maintain a desired engine speed, based on the changes to the friction profile.

15. The method of claim 13, further comprising indicating a change in performance of an engine component in response to a change in the friction profile greater than a threshold friction amount, wherein indicating the change in performance of the engine component includes:

indicating reduced compression sealing of an engine cylinder and degradation of one or more of a piston liner, piston ring, or a valve of the engine cylinder in response to the friction profile decreasing by at least the threshold friction amount; and

indicating increased friction on rotating parts of the engine due to one or more of increased deposit buildup, reduced lubrication, degraded bearings, or such other wear-contributing mechanisms/modes in response to the friction profile increasing by at least the threshold friction amount.

16. The method of claim 13, further comprising adjusting each measured drop rate in engine speed based on one or more of a starting engine speed after fueling a final cylinder of the engine during the engine shutdown event, skip fire parameters of the engine prior to the engine shutdown event, alternator torque during the engine shutdown event, or an altitude of the engine during the engine shutdown event.

17. A system for an engine, comprising:

a first crankshaft speed sensor; and

a controller operatively coupled to the first crankshaft speed sensor and configured to;

determine a first rate of decrease in engine speed output by the first crankshaft speed sensor during an engine shutdown event; and

indicate a change in performance of the first crankshaft speed sensor in response to the determined first rate of decrease in engine speed differing from a reference rate of decrease in engine speed by a threshold rate, the reference rate based on a model of expected engine speed decay during the engine shutdown event for the engine.

18. The system of claim 17, wherein the controller is further configured to update the model of expected engine speed decay based on the determined first rate of decrease in engine speed during the engine shutdown event and to determine a new reference rate based on the model that is updated.

19. The system of claim 17, further comprising a second crankshaft speed sensor positioned proximate to the first crankshaft speed sensor, wherein the controller is further configured to:

determine a second rate of decrease in engine speed output by the second crankshaft speed sensor during the engine shutdown event;

compare the first rate with the second rate; and

indicate the change in performance of the first crankshaft speed sensor in response to the first rate differing from the reference rate by the threshold rate and the second rate not differing from the reference rate by the threshold rate.

20. The system of claim 19, further comprising an engine cylinder, wherein the controller is further configured to:

indicate mechanical degradation of the engine cylinder in response to both the first rate and the second rate differing from the reference rate by less than the threshold rate;

update a friction profile of the engine based on the first rate; and

indicate reduced compression sealing of the engine cylinder in response to a reduction in the friction profile by greater than a threshold amount.