System and method for reducing engine oil dilution

Patent metadata

Field	Value
Publication number	US-9988954-B2
Application number	US-201615199410-A
Country	US
Kind code	B2
Filing date	Jun 30, 2016
Priority date	Jun 30, 2016
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

Methods and systems are provided for filtering an oil dilution amount based on a current value of the oil dilution amount. In one example, filtering the oil dilution amount may include decreasing a sensitivity of filtering at lower oil dilution below a threshold; otherwise, increasing the sensitivity of filtering. The sensitivity of the filtering may be decreased by implementing a larger time constant, while the sensitivity of the filtering may be increased by implementing a smaller time constant.

First claim

The invention claimed is:

1. A method for a vehicle engine, comprising:
with a vehicle engine controller,
determining a filtered oil dilution amount by filtering, with the controller, an estimated oil dilution data value of an engine oil; and
indicating oil degradation based on the filtered oil dilution amount,
wherein an amount of filtering is adjusted by adjusting a filter time constant of a filter within the controller based on the estimated oil dilution data value, and
wherein the estimated oil dilution data value is based on a number of regeneration events of a particulate filter within an exhaust of a vehicle, a vehicle speed indication from a vehicle speed sensor, and a vehicle mileage from a fuel usage sensor; and
generating a message to display an oil service interval, the oil service interval based on the filtered oil dilution amount.

2. The method of claim 1 , wherein adjusting the amount of filtering includes, responsive to the estimated oil dilution data value below a first threshold amount, increasing the amount of filtering; otherwise, decreasing the amount of filtering.

3. The method of claim 2 , wherein increasing the amount of filtering includes implementing a larger filter time constant for the filtering, and wherein decreasing the amount of filtering includes implementing a smaller filter time constant for the filtering.

4. The method of claim 3 , further comprising, responsive to an oil change, implementing the smaller filter time constant for the filtering.

5. The method of claim 3 , wherein indicating oil degradation includes, responsive to the filtered oil dilution amount above a second threshold amount, providing an indication to a user via a human-machine interface of the vehicle, the indication comprising a request to change engine oil; and wherein the second threshold amount is greater than the first threshold amount.

6. The method of claim 1 , wherein indicating oil degradation includes estimating a percentage of oil life remaining based on the filtered oil dilution amount, an average vehicle speed over a threshold driving distance, a fuel consumption rate over the threshold distance, and an engine oil temperature.

7. The method of claim 6 , further comprising displaying a remaining distance to oil change in calibrated steps based on the percentage of oil life remaining and wherein displaying the remaining distance to oil change in calibrated steps includes utilizing a first step size until a first distance threshold is reached; utilizing a second step size, smaller than the first step size, between the first distance threshold and a second distance threshold; and utilizing a third step size, smaller than the second step size, at and after the second distance threshold.

8. The method of claim 1 , further comprising adjusting the amount of filtering based on a period between two samples.

9. The method of claim 8 , wherein adjusting the amount of filtering based on the period includes increasing the filter time constant as the period increases.

10. The method of claim 1 , wherein the oil dilution data value is estimated based on a number of regeneration events of a diesel particulate filter located in an exhaust of the engine.

11. A method for an engine, comprising:
via an engine controller,
estimating a fuel in oil dilution data value;
using the estimated fuel in oil dilution data value as an input to a filter; and
responsive to the estimated fuel in oil dilution data value less than a threshold dilution, selecting a first time constant for the filter; otherwise, selecting a second time constant for the filter,
wherein the first time constant is larger than the second time constant, and
wherein the filter is a single pole low pass filter; and
generating a message to display an oil service interval, the oil service interval based on the filtered fuel in oil dilution.

12. The method of claim 11 , further comprising determining a distance to service based on an output of the filter.

13. The method of claim 12 , wherein the distance to service is further based on a vehicle speed, a vehicle mileage, and an average oil temperature during a threshold distance of vehicle operation; and further comprising, responsive to the distance to service greater than a threshold distance, indicating engine oil degradation to a user via a display within a vehicle at engine start-up.

14. The method of claim 13 , further comprising indicating the distance to service via the display based on a user request.

15. The method of claim 11 , further comprising, responsive to the estimated fuel in oil dilution data value less than the threshold dilution and a period between two samples for the filter less than a threshold period, decreasing the first time constant but maintaining the first time constant above the second time constant; and, responsive to the estimated fuel in oil dilution data value greater than the threshold dilution and the period between two samples for the filter greater than a second threshold period, increasing the second time constant but maintaining the second time constant below the first time constant.

16. The method of claim 11 , wherein the fuel in oil dilution data value is estimated based on a duration of engine operation and a fuel injection timing.

17. A method for a vehicle, comprising:
at a controller within the vehicle,
estimating an amount of fuel in engine oil based on a number of regeneration events of a particulate filter within an exhaust of the vehicle, a vehicle speed, and a vehicle mileage;
generating a filtered amount of fuel in engine oil by filtering the estimated amount of fuel in engine oil;
estimating an oil degradation amount based on the filtered amount of fuel in engine oil; and
generating a message to display an oil service interval, the oil service interval based on the oil degradation amount,

wherein a sensitivity of the filtering is adjusted by implementing different time constants based on the estimated amount of fuel in engine oil.

18. The method of claim 17 , wherein the filtering includes low-pass filtering, and wherein adjusting the sensitivity of the filtering includes decreasing the sensitivity by utilizing a first larger time constant for the filtering when the estimated amount of fuel in engine oil is below a first threshold amount; otherwise, increasing the sensitivity by utilizing a second smaller time constant for the filtering.

19. The method of claim 17 , further comprising, responsive to the filtered amount of fuel in engine oil greater than a second threshold amount, generating a message to display at next engine start at a human-machine interface within the vehicle, the message including a request to a user to replace engine oil, wherein the second threshold amount is greater than a first threshold amount.

Assignees

• Ford Global Tech Llc

Inventors

• Macfarlane Kevin
• Witt Dennis
• Perkins Amanda
• Semanson Christopher
• Milton Robert
• Rackmil Charles Irwin

Classifications

• F01M2001/1007

  characterised by the purification means combined with other functions · CPC title

• F01M1/16 Primary

  Controlling lubricant pressure or quantity (rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22) · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title

• F01M2250/66

  Vehicle speed · CPC title

• F01M1/10

  Lubricating systems characterised by the provision therein of lubricant venting or purifying means, e.g. of filters · CPC title