Claims:We Claim

1. An algorithm (10) for predicting a remaining useful life of engine oil in an oil sump of an internal combustion engine, the algorithm (10) comprising the steps of:
employing an engine oil dilution mathematical model (12) to determine the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine and a quantity of fuel and engine oil that evaporates from a crank-case of the internal combustion engine;
employing an iron concentration mathematical model (14) to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine;
employing a distance model (16) to determine a distance that has been traversed since engine oil was changed in the internal combustion engine;
employing an oil sump temperature model (18) to determine a variation of a temperature of the engine oil that is present within the oil sump from a time period when the engine oil was changed in the oil sump;
employing a year based model (20) to determine a duration of time for which the engine oil within the oil sump is present from when the engine oil was previously changed in the oil sump of the internal combustion engine.

2. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine in accordance with Claim 1, wherein employing an engine oil dilution mathematical model (12) to determine the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine further comprises determining the quantity of post injections of pressurized fuel from the time when the engine oil was changed in the oil sump until the present time.

3. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 2, wherein employing an engine oil dilution mathematical model (12) to determine a quantity of fuel and engine oil that evaporates from a crank-case of the internal combustion engine further comprises empirically determining the quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine based on a time duration for when the engine oil was changed in the oil sump until the present time.

4. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 3, wherein the engine oil dilution mathematical model is equal to [100 – (Fuel present in engine oil based on the quantity of post injections of pressurized fuel from the time period when the engine oil was changed in the oil sump) – (determined quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine based on a time duration for which the engine oil is present in the oil sump from when the engine oil was changed in the oil sump)] / (Mass of engine oil when the engine oil was changed in the oil sump).

5. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 1, wherein employing an iron concentration mathematical model (14) to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine further comprises determining the quantity of iron that is deposited in the crank-case of the internal combustion engine during a start of the internal combustion engine by means of the formula [100- (Sump Temperature Concentration * Engine Oil Injection Dilution Factor * Cranking Time Factor * Engine ON Factor)] / Iron Threshold.

6. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 1, wherein employing an iron concentration mathematical model (14) to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine further comprises determining the quantity of iron that is deposited in the crank-case of the internal combustion engine during a running operation of the internal combustion engine by means of the formula [100- (Operating Point Concentration * Sump Temperature Concentration * Engine ON Factor)] / Threshold of Iron.

7. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 1, wherein employing an oil sump temperature model (18) to determine a variation of a temperature of the engine oil that is present within the oil sump from a time period when the engine oil was changed in the oil sump further comprises determining the oil sump temperature model during a running operation of the internal combustion engine by means of the formula [100 – (Engine oil Temperature and Engine Speed Based Counts)] / Temperature Counts Threshold.

8. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 1, wherein a minimum value (22) that is expressed as a percentage of the engine oil dilution mathematical model (12), the iron concentration mathematical model (14), the distance model (16), the oil sump temperature model (18), and the year based model (20) is determined.

9. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 8, wherein the minimum value (22) that is expressed as a percentage of the engine oil dilution mathematical model (12), the iron concentration mathematical model (14), the distance model (16), the oil sump temperature model (18), and the year based model (20) is divided (24) by 100 and multiplied (26) by a threshold distance that is defined by a user to compute a remaining useful engine oil life of the engine oil.

10. The algorithm (10) for predicting the remaining useful life of engine oil in an oil sump of the internal combustion engine (10) in accordance with Claim 9, wherein the remaining useful engine oil life of the engine oil is used to compute a distance that may be traversed before the engine oil needs to be replaced.
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to an internal combustion engine, and more specifically to an algorithm for predicting a remaining useful life of engine oil in an oil sump of the internal combustion engine.

Background of the invention
[0002] US 6327900 BA describes a method for advising a motor vehicle operator of the need to change the lubricating oil in a direct or an indirect injection diesel engine. The rate of degradation of the oil is determined from monitoring engine revolutions, engine oil temperature and engine oil contamination content. At the start of service after an oil change has occurred, a value corresponding to the maximum allowed number of engine revolutions for the useful life of the engine oil is stored in the memory of the vehicle's computer. Periodically during each period of vehicle operation, an effective engine revolutions value is determined in relation to the product of measured engine revolutions, an engine oil temperature dependent penalty factor and an engine oil contaminant content dependent penalty factor. The penalty factors increase the effective engine revolutions value to compensate for engine operating conditions that tend to cause increased degradation of the engine oil. The effective engine revolutions value is subtracted from the stored maximum number of engine revolutions resulting in a remaining allowed revolutions value. Each time the effective engine revolutions value is calculated and subtracted from the remaining allowed engine revolutions value, a new remaining allowed revolutions value is stored in the memory, replacing the old value. When the stored remaining allowed revolutions value is decreased below a predetermined threshold value indicating the end of the engine oil's useful life, an indicator advising the operator that the engine oil needs to be changed is activated.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of an algorithm for predicting a remaining useful life of engine oil in an oil sump of an internal combustion engine in one embodiment of the invention.

Detailed description of the embodiments
[0005] Figure 1 illustrates an algorithm 10 for predicting a remaining useful life of engine oil in an oil sump of an internal combustion engine. The algorithm 10 comprises the steps of employing an engine oil dilution mathematical model 12 to determine the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine and a quantity of fuel and engine oil that evaporates from a crank-case of the internal combustion engine. The algorithm further comprises the steps of employing an iron concentration mathematical model 14 to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine, and employing a distance model 16 to determine a distance that has been traversed since engine oil was changed in the internal combustion engine. Moreover, the algorithm further comprises the steps of employing an oil sump temperature model 18 to determine a variation of a temperature of the engine oil that is present within the oil sump from a time period when the engine oil was changed in the oil sump, and employing a year based model 20 to determine a duration of time for which the engine oil within the oil sump is present from when the engine oil was previously changed in the oil sump of the internal combustion engine.

[0006] Figure 1 illustrates an algorithm 10 for predicting a remaining useful life of engine oil in an oil sump of an internal combustion engine. The algorithm 10 comprises the steps of employing an engine oil dilution mathematical model 12 to determine the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine. More specifically, the step of employing an engine oil dilution mathematical model 12 to determine a the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine further comprises determining the quantity of post injections of pressurized fuel from the time period from when the engine oil was changed in the oil sump until the present time. Therefore, from the time when the engine oil was changed in the oil sump until the present time, the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion is determined. More specifically, the time duration for which soot particles are regenerated within the diesel particulate filter is used as a basis to compute a post injection time for which the pressurized fuel is injected into the engine crank-case during post injection. Based on the cumulative sum of the post injection times over several regenerative cycles for which the pressurized fuel is flowing into the engine crank-case, the total duration of time when the engine oil was changed in the oil sump is determined. Therefore the quantity of the pressurized fuel during post injections that is flowing into the crank-case may be determined accordingly.

[0007] The algorithm comprises the steps of employing an engine oil dilution mathematical model 12 to determine a quantity of fuel and engine oil that evaporates from a crank-case of the internal combustion engine. - employing the engine oil dilution mathematical model 12 to determine a quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine further comprises empirically determining the quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine based on a time duration for which the engine oil is present in the oil sump from when the engine oil was changed in the oil sump of the internal combustion engine. Therefore, from the time when the engine oil was changed in the oil sump, the quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine is determined. The engine oil dilution mathematical model is equal to [100 – (Fuel present in engine oil based on the quantity of post injections of pressurized fuel from the time period when the engine oil was changed in the oil sump) – (determined quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine based on a time duration for which the engine oil is present in the oil sump from when the engine oil was changed in the oil sump)] / (Mass of engine oil when the engine oil was changed in the oil sump). The above mathematical formula that is used to compute the quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine.

[0008] The algorithm 10 further comprises the steps of employing an iron concentration mathematical model 14 to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine. The step of employing an iron concentration mathematical model 14 to determine the quantity of iron that is deposited in the crank-case of the internal combustion engine further comprises determining the quantity of iron that is deposited in the crank-case of the internal combustion engine during a starting phase of the internal combustion engine by means of the formula [100- (Sump Temperature Concentration * Engine Oil Injection Dilution Factor * Cranking Time Factor * Engine ON Factor)] / Iron Threshold. Therefore during the starting phase of the engine, the quantity of iron that is deposited in the crank-case of the internal combustion engine due to the abrasive movement of the piston against the walls of the crank-case of the engine is determined by means of the above formula. The step of employing an iron concentration mathematical model to determine a quantity of iron that is deposited in the crank-case of the internal combustion engine further comprises determining the quantity of iron that is deposited in the crank-case of the internal combustion engine during a running operation phase of the internal combustion engine by means of the formula [100- (Operating Point Concentration * Sump Temperature Concentration * Engine ON Factor)] / (Threshold of Iron). Therefore during the running operation phase of the engine, the quantity of iron that is deposited in the crank-case of the internal combustion engine due to the abrasive movement of the piston against the walls of the crank-case of the engine is determined by means of the above formula.

[0009] In an exemplary embodiment, a distance model 16 is employed to determine a distance that has been traversed since engine oil was previously changed in the internal combustion engine. More specifically, the distance model 16 is obtained directly from an odometer of a vehicle to compute the distance that has been traversed by the vehicle since engine oil was changed in the oil sump. Moreover, the algorithm 10 further comprises the steps of employing an oil sump temperature model 18 to determine a variation of a temperature of the engine oil that is present within the oil sump from a time period when the engine oil was changed in the oil sump. More specifically, employing an oil sump temperature model 18 to determine a variation of a temperature of the engine oil that is present within the oil sump from a time period when the engine oil was changed in the oil sump further comprises employing the oil sump temperature model 18 during the running operation phase of the internal combustion engine by means of the formula [100 – (Engine oil Temperature and Engine Speed Based Counts)] / (Temperature Counts Threshold). Therefore, during the running operation of the internal combustion engine, the oil sump temperature model 18 during the running operation phase of the internal combustion engine is determined by means of this formula.

[0010] Once the engine oil dilution mathematical model 12 to determine the quantity of the pressurized fuel during post injections that is flowing into the crank-case of the internal combustion engine, and a quantity of fuel and engine oil that evaporates from the crank-case of the internal combustion engine is determined, iron concentration mathematical model 14, a distance model 16 from the last engine oil change, an oil sump temperature model 18 that depicts the variation in the temperature of engine oil in the oil sump since the engine oil was changed in the oil sump, and a year based model 20 are each determined, the minimum value 22 that is expressed as a percentage of the engine oil dilution mathematical model 12, the iron concentration mathematical model 14, the distance model 16, the oil sump temperature model 18, and the year based model 20 is determined. Once the minimum value 22 that is expressed as a percentage of the engine oil dilution mathematical model 12, the iron concentration mathematical model 14, the distance model 16, the oil sump temperature model 18, and the year based model 20 is determined, the minimum value 22 is divided 24 by 100 and multiplied 26 by a allowed threshold distance that is defined to compute a remaining useful engine oil life of the engine oil.

[0011] Once the remaining useful engine oil life of the engine oil is determined, the remaining useful engine oil life of the engine oil is used to compute the distance that may be traversed before the engine oil needs to be completely replaced. More specifically, the remaining useful engine oil life of the engine oil may be calibrated in terms of the distance that may be traversed before the engine oil needs to be completely replaced in the engine. This information shall be displayed on the infotainment

[0012] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and constitute a part of this invention. The scope of the invention is only limited by the scope of the claims.