SYSTEM AND METHOD FOR DIAGNOSING AN ENGINE

• US 20130073174A1
• Filed: 09/15/2011
• Published: 03/21/2013
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: GE Global Sourcing LLC (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: Bret Dwayne Worden, Matthew Malone, Milan Karunaratne, Paul Lloyd Flynn
• Inventors: KARUNARATNE, Milan, FLYNN, Paul Lloyd, WORDEN, Bret Dwayne, MALONE, Matthew
• Granted Patent: US 9,447,745 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F02D 2041/228 Warning displays
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 2250/08 Engine blow-by from crankcase chamber
• 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: Y02T 10/40 Engine management systems

Abstract

Methods and systems are provided for an engine including a crankcase. A condition of the engine may be diagnosed based on frequency content of crankcase pressure. Different types of degradation may be distinguished based on a frequency content of multiple frequencies of the crankcase pressure. Thus, a degraded engine component may be identified in a manner that reduces service induced delay.

Claims

1. A method for an engine including a crankcase, comprising:

diagnosing a condition of the engine based on frequency content of a measured crankcase pressure.

2. The method of claim 1, wherein diagnosing the engine condition includes identifying whether there is degradation of one or both of an engine cylinder or an engine cylinder related component.

3. The method of claim 2, wherein diagnosing the engine condition includes determining an increased blow-by condition of one or both of a degraded engine cylinder or a degraded engine cylinder related component, and the condition is based at least in part on a power stroke frequency component of the frequency content of the crankcase pressure that exceeds a power stroke frequency component threshold value.

4. The method of claim 3, wherein the engine is a four stroke engine and the power stroke frequency is about half of a crankshaft revolution frequency, and diagnosing the engine condition includes identifying a magnitude of the power stroke frequency component being greater than a power stroke frequency component threshold value.

5. The method of claim 2, further comprising derating engine power in response to a positive identification of degradation of the engine cylinder or the engine cylinder related component.

6. The method of claim 2, further comprising reducing an amount of fuel injected into the degraded engine cylinder in response to a positive identification of degradation of the engine cylinder.

7. The method of claim 2, further comprising correlating crankcase pressure information to one or more of a crankshaft position, camshaft position, or a fuel injection sequence.

8. The method of claim 2, further comprising determining a power stroke frequency component of the frequency content;

and

selectively disabling fuel injection to one or more cylinders of the engine based at least in part on the power stroke frequency component.

9. The method of claim 3, further comprising varying engine fuel injection to an engine cylinder;

and

monitoring for a resulting change in the frequency content caused by the fuel injection variation.

10. The method of claim 3, wherein the engine is a two stroke engine and the power stroke frequency is about a crankshaft revolution frequency, and diagnosing the engine condition includes identifying a magnitude of the power stroke frequency component being greater than a power stroke frequency component threshold value.

11. The method of claim 1, further comprising:

measuring an average crankcase pressure;

comparing the measured average crankcase pressure to a first average crankcase pressure threshold value;

determining a first order frequency component of the frequency content, the first order frequency about a crankshaft revolution frequency;

comparing a magnitude of the first order frequency component to a first order frequency threshold value; and

determining degradation of the crankcase based at least in part on whether the measured average crankcase pressure exceeds the first average crankcase pressure threshold value and the magnitude of the first order frequency component is less than the first order frequency threshold value.

12. The method of claim 1, further comprising:

measuring an average crankcase pressure, wherein the engine is a four stroke engine;

comparing the measured average crankcase pressure to an average crankcase pressure threshold value;

determining degradation of one or both of a turbocharger and a crankcase evacuation system based at least in part on whether the measured average crankcase pressure exceeds the average crankcase pressure threshold value; and

determining whether the frequency content of the crankcase pressure includes a half-order frequency component that is less than a half-order frequency component threshold value, wherein the half-order frequency is at about half a crankshaft revolution frequency.

13. A method for an engine including a crankcase enclosing a crankshaft, comprising:

distinguishing between different types of degradation based on a frequency content of a measured crankcase pressure.

14. The method of claim 13, wherein the engine is a four stroke engine and the frequency content includes a half-order component substantially at half the crankshaft revolution, the method further comprising distinguishing, based at least in part on an average crankcase pressure, the type degradation from a determined set of degradation types.

15. The method of claim 14, further comprising:

comparing the average crankcase pressure to a first average crankcase pressure threshold value; and

detecting a magnitude of the half-order component of the frequency content that is less than a second magnitude threshold value; and

determining degradation of one or both of a turbocharger or a crankcase evacuation system.

16. The method of claim 14, further comprising diagnosing a blow-by condition of the engine in response to detection that a magnitude of the half-order component of the frequency content exceeds a determined magnitude threshold value.

17. The method of claim 16, further comprising basing at least one of the first average crankcase pressure threshold value or the second magnitude threshold value on one or more of engine speed, engine load, crankcase temperature, or historical engine data.

18. A vehicle system, comprising:

an engine including a crankcase, a crankcase pressure sensor, and a crankshaft enclosed by the crankcase; and

a controller including instructions configured to;

sample and transform a signal from the crankcase pressure sensor to identify frequency content of the crankcase pressure;

diagnose a condition of the engine based on the frequency content of the crankcase pressure; and

adjust an engine operating parameter based on the diagnosed condition.

19. The vehicle system of claim 18, wherein the controller is operable to report a blow-by condition when a magnitude of a half-order component of the frequency content exceeds a threshold, wherein the engine is a four-stroke engine and the half-order component is substantially at a frequency half of the crankshaft revolution frequency.

20. A test kit, comprising:

a controller that is operable to determine a condition of an engine based on a frequency content of pressure readings of a crankcase associated with the engine.

21. The test kit of claim 20, further comprising one or more crankcase pressure sensors configured to be coupled to die crankcase to sense the crankcase pressure, wherein the controller is operable to communicate with the one or more crankcase pressure sensors, and the controller is further operable to transform signals from the one or more crankcase pressure sensors into the frequency content that represents pressure frequency information of the crankcase.