System and method for reducing engine oil dilution
First Claim
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1. A method for a vehicle engine, comprising:
- determining an oil dilution amount based on an integrated difference between a first air-to-fuel ratio and a second air-to-fuel ratio, wherein the first air-to-fuel ratio comprises a commanded air-to-fuel ratio, and wherein the second air-to-fuel ratio comprises an engine air-to-fuel ratio based on an oxygen sensor output;
advancing a fuel injection timing with respect to a base fuel injection timing in a first combustion cycle to reduce oil dilution in response to the oil dilution amount being greater than a threshold dilution amount; and
applying the base fuel injection timing when the oil dilution amount is less than the threshold dilution amount.
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Abstract
Methods and systems are provided for modeling an oil dilution qualitative indicator based on an integrated difference between a commanded air-to-fuel ratio and an engine air-to-fuel ratio as determined via an oxygen sensor, cumulative cold engine temperature operating duration, and fuel injection characteristics (timing, duration, number of injections) allowing fuel injection timing modifications that minimize oil dilution when the oil dilution qualitative indicator is greater than a threshold level.
24 Citations
18 Claims
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1. A method for a vehicle engine, comprising:
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determining an oil dilution amount based on an integrated difference between a first air-to-fuel ratio and a second air-to-fuel ratio, wherein the first air-to-fuel ratio comprises a commanded air-to-fuel ratio, and wherein the second air-to-fuel ratio comprises an engine air-to-fuel ratio based on an oxygen sensor output; advancing a fuel injection timing with respect to a base fuel injection timing in a first combustion cycle to reduce oil dilution in response to the oil dilution amount being greater than a threshold dilution amount; and applying the base fuel injection timing when the oil dilution amount is less than the threshold dilution amount. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for an engine, comprising:
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during a first condition when an oil dilution amount is greater than a threshold, adjusting a fuel injection timing earlier; and during a second condition when the oil dilution amount is less than the threshold, adjusting a fuel injection timing later than the earlier timing, the oil dilution amount based on an integrated difference between a commanded air-to-fuel ratio and an engine air-to-fuel ratio determined via an oxygen sensor. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for an engine, comprising:
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calculating an oil dilution level based on an integrated difference between a commanded air-to-fuel ratio and an engine air-to-fuel ratio when an engine temperature is less than a threshold temperature; adjusting a fuel injection timing of multiple injections per combustion cycle earlier before top dead center of a cylinder receiving fuel in response to the oil dilution level being greater than a threshold level; and adjusting fuel injection timing for at least one injection per combustion cycle later before top dead center of the cylinder receiving fuel in response to the oil dilution level being less than the threshold level. - View Dependent Claims (16, 17, 18)
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Specification