A coolant control system of a vehicle includes a fraction module, and a coolant valve control module. The fraction module determines an oil fuel fraction based on an amount of fuel in an amount of engine oil. The coolant valve control module, based on the oil fuel fraction, selectively actuates a coolant valve to enable coolant flow from an integrated exhaust manifold (IEM) of an engine to an engine oil heat exchanger.

A coolant control system of a vehicle includes a fraction module, and a coolant valve control module. The fraction module determines an oil fuel fraction based on an amount of fuel in an amount of engine oil. The coolant valve control module, based on the oil fuel fraction, selectively actuates a coolant valve to enable coolant flow from an integrated exhaust manifold (IEM) of an engine to an engine oil heat exchanger.

A method (500) and apparatus (10-5) for carrying out the 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 (505); determining an amount of fuel flow into the engine oil during one or more enrichment phases of engine operation (510); determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine on (515); determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine off (520); 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 (525); and 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 (540).

A method (500) and apparatus (10-5) for carrying out the 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 (505); determining an amount of fuel flow into the engine oil during one or more enrichment phases of engine operation (510); determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine on (515); determining an amount of fuel evaporated from the engine oil during one or more phases of vehicle operation with the engine off (520); 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 (525); and 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 (540).