Vehicular coolant system and method of controlling the same

A method for controlling a coolant system, the coolant system including a battery coolant line fluidly connected to a battery, a power electronics coolant line fluidly connected to a power electronic component, a radiator coolant line fluidly connected to a radiator, and a control valve configured to control flow of a coolant through the battery coolant line, the power electronics coolant line, and the radiator coolant line, the method comprising:

• obtaining a temperature of a heat sink of the power electronic component;
• determining whether a variation of the temperature of the heat sink of the power electronic component is greater than or equal to a predetermined threshold in a first circulation mode in which the power electronics coolant line is fluidly separated from the battery coolant line;
• based on determining that the variation of the temperature of the heat sink of the power electronic component is greater than or equal to the predetermined threshold, switching to a second circulation mode in which the power electronics coolant line is fluidly connected to the battery coolant line;
• obtaining a first temperature sensed by a temperature sensor that is disposed at the battery coolant line;
• and
• determining a second temperature of the coolant passing through the power electronics coolant line based on the first temperature sensed by the temperature sensor disposed at the battery coolant line.

A method for controlling a coolant system, the coolant system including a battery coolant line fluidly connected to a battery, a power electronics coolant line fluidly connected to a power electronic component, a radiator coolant line fluidly connected to a radiator, and a control valve configured to control flow of a coolant through the battery coolant line, the power electronics coolant line, and the radiator coolant line, the method comprising:

• obtaining a temperature of a heat sink of the power electronic component;
• determining whether a variation of the temperature of the heat sink of the power electronic component is greater than or equal to a first predetermined threshold in a first circulation mode in which the power electronics coolant line is fluidly separated from the battery coolant line and the radiator coolant line;
• based on determining that the variation of the temperature of the heat sink of the power electronic component is greater than or equal to the first predetermined threshold, determining a temperature difference between a first temperature of the coolant passing through the battery coolant line and the temperature of the heat sink;
• determining whether the temperature difference is greater than or equal to a second predetermined threshold;
• based on determining that the temperature difference is greater than or equal to the second predetermined threshold, switching to a second circulation mode in which the power electronics coolant line is fluidly connected to the radiator coolant line;
• and
• obtaining a first sensor temperature sensed by a first temperature sensor disposed at the radiator coolant line;
• and
• determining a second temperature of the coolant passing through the power electronics coolant line based on the first sensor temperature sensed by the first temperature sensor disposed at the radiator coolant line.