Engine coolant cooling system for vehicle

An engine coolant cooling system for a vehicle, the engine coolant cooling system comprising:

• a radiator including an inlet tank provided with an inlet nipple for inflow of coolant, an outlet tank provided with an outlet nipple for discharging the coolant, and a radiator core including a plurality of coolant passages connected between the inlet tank and the outlet tank to heat-dissipate the coolant;
• an inlet valve unit mounted in an internal flow path of the inlet tank to selectively divide the internal flow path of the inlet tank into a first inlet flow path fluidically-communicating with the inlet nipple and a second inlet flow path separated from the inlet nipple;
• an outlet valve unit mounted in an internal flow path of the outlet tank to selectively divide the internal flow path of the outlet tank into a first outlet flow path fluidically-communicating with the outlet nipple and a second outlet flow path not fluidically-communicating with the outlet nipple;
• and
• a controller configured for controlling operations of the inlet valve unit and the outlet valve unit according to a temperature of the coolant,
• wherein a predetermined passage among the plurality of coolant passages connected to the second outlet flow path is connected to the first inlet flow path, and a coolant passage not connected to the first inlet flow path among the plurality of coolant passages connected to the second outlet flow path is connected to the second inlet flow path,
• wherein the controller is configured to selectively operate the inlet valve unit to divide the internal flow path of the inlet tank into the first inlet flow path and the second inlet flow path, and configured to selectively operate the outlet valve unit to divide the internal flow path of the outlet tank into the first outlet flow path and the second outlet flow path, when the temperature of the coolant is equal to or higher than a first reference temperature,
• wherein the controller is configured to not operate the inlet valve unit and the outlet valve unit, when the temperature of the coolant is lower than the first reference temperature,
• wherein an engine water pump and an electronic water pump for circulating the coolant are mounted between the radiator and an engine, and the electronic water pump is driven according to the temperature of the coolant to increase a flow rate of the coolant circulated in the engine and the radiator by the engine water pump, and
• wherein the controller is configured to operate the engine water pump and does not operate the electronic water pump, when the temperature of the coolant is lower than the first reference temperature.