Method and apparatus for mitigating fuel in oil

A method of mitigating fuel in oil in an internal combustion engine of a hybrid electric vehicle, the method comprising:

• determining an amount of fuel flow into the engine oil during one or more cold start phases of engine operation;
• determining an amount of fuel flow into the engine oil during one or more enrichment phases of engine operation;
• determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine on;
• determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine off;
• determining a percentage of fuel in the engine oil from the amount of fuel flow into the engine oil and the amount of fuel evaporated from the engine oil;
• modifying vehicle operation based on the percentage of fuel in the engine oil exceeding a first fuel in oil threshold or a second fuel in oil threshold;
• and when the percentage of fuel in the engine oil exceeds the first fuel in oil threshold and is less than the second fuel in oil threshold, inhibiting an engine stop unless the vehicle speed is below a first threshold vehicle speed or braking of the vehicle is effected at a vehicle speed below a second threshold vehicle speed.