Method for detecting a condition of engine oil

• US 7,826,987 B2
• Filed: 07/19/2007
• Issued: 11/02/2010
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Aikawa, Koichiro
• Primary Examiner(s): Dunn; Drew A
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US11/826,869
• Publication Number:
  US 20080027661A1
• Time in Patent Office: 1,202 Days
• Field of Search: 702/50, 731/172, 731/13, 701/1, 701/123, 340/438, 340/450.3, 123/568.11, 123/572, 123/568.28, 123/196.R
• US Class Current: 702/50
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 2011/14 for indicating the necessity to change the oil
• CPC Class Codes: F02D 2250/08 Engine blow-by from crankcase chamber
• CPC Class Codes: F02D 2250/11 Oil dilution, i.e. prevention thereof or special controls according thereto

Abstract

Provided is a method for detecting a condition of engine oil that allows the progress of degradation of engine oil to be more accurately determined without incurring any significant cost. In a method for detecting a state of engine oil by defining a degradation index that changes with a progress in degradation of the engine oil that lubricates an internal combustion engine and determining a progress of the degradation of the engine oil according to the degradation index, a value related to a concentration of blow-by gas that flows into a crankcase of the engine is computed, and the degradation index is computed according to the computed value related to a concentration of blow-by gas that flows into a crankcase of the engine. The degradation index may consist of a total base number of the engine oil, and the concentration of blow-by gas that flows into a crankcase of the engine may consist of a NOx concentration.

Claims

1. A method for detecting a condition of engine oil, comprising:

defining a degradation index that changes with a progress in degradation of the engine oil that lubricates an internal combustion engine;

computing a value related to a concentration of blow-by gas that flows into a crankcase of the engine; and

computing the degradation index according to the computed value related to a concentration of blow-by gas that flows into a crankcase of the engine.

2. The method for detecting a condition of engine oil according to claim 1, further comprising detecting a temperature of the engine oil, the computed degradation index being modified according to the detected engine oil temperature.

3. The method for detecting a condition of engine oil according to claim 1, wherein computing the degradation index comprises computing a change rate of the degradation index according to the computed value related to a concentration of blow-by gas that flows into a crankcase of the engine, and computing the degradation index by integrating the computed change rate of the degradation index.

4. The method for detecting a condition of engine oil according to claim 1, further comprising detecting a temperature of the engine oil, the computed change rate of the degradation index being modified according to the detected engine oil temperature.

5. The method for detecting a condition of engine oil according to claim 1, wherein the degradation index consists of a total base number of the engine oil.

9. The method for detecting a condition of engine oil according to claim 1, further comprising determining a progress of the degradation of the engine oil according to the computed degradation index.

6. A method for detecting a condition of engine oil, comprising:

defining a degradation index that changes with a progress in degradation of the engine oil that lubricates an internal combustion engine;

computing a value related to a concentration of blow-by gas that flows into a crankcase of the engine; and

computing the degradation index according to the computed value related to a concentration of blow-by gas that flows into a crankcase of the engine;

wherein the concentration of blow-by gas that flows into a crankcase of the engine consists of a NOx concentration.

7. The method for detecting a condition of engine oil according to claim 6, wherein the NOx concentration is computed from at least one of a crankshaft rotational speed, load, valve lift and valve timing of the engine.

8. The method for detecting a condition of engine oil according to claim 6, wherein the NOx concentration is modified by at least one of a relative humidity, ignition timing and fuel injection.

10. A method for detecting a condition of engine oil, comprising:

defining a degradation index that changes with a progress in degradation of the engine oil that lubricates an internal combustion engine;

computing a value related to a concentration of blow-by gas that flows into a crankcase of the engine;

computing a change rate of the degradation index according to the computed value related to a concentration of blow-by gas that flows into a crankcase of the engine; and

computing the degradation index by integrating the computed change rate of the degradation index.

11. The method for detecting a condition of engine oil according to claim 10, further comprising detecting a temperature of the engine oil, the computed degradation index being modified according to the detected engine oil temperature.

12. The method for detecting a condition of engine oil according to claim 10, further comprising detecting a temperature of the engine oil, the computed change rate of the degradation index being modified according to the detected engine oil temperature.

13. The method for detecting a condition of engine oil according to claim 10, wherein the degradation index consists of a total base number of the engine oil.

14. The method for detecting a condition of engine oil according to claim 10, wherein the concentration of blow-by gas that flows into a crankcase of the engine consists of a NOx concentration.

15. The method for detecting a condition of engine oil according to claim 14, wherein the NOx concentration is computed from at least one of a crankshaft rotational speed, load, valve lift and valve timing of the engine.

16. The method for detecting a condition of engine oil according to claim 14, wherein the NOx concentration is modified by at least one of a relative humidity, ignition timing and fuel injection.

17. The method for detecting a condition of engine oil according to claim 10, further comprising determining a progress of the degradation of the engine oil according to the computed degradation index.