System and method for reducing engine oil dilution

摘要

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.

主权项

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.