Cooling system for water-cooled internal combustion engine and control method applicable to cooling system therefor

A cooling system for a water-cooled internal combustion engine, comprising:

• a heat exchanger to circulate a coolant flowing out from the water-cooled engine into tubes arranged in a space between headers thereof to cool the coolant;
• a pump driven independently of the water-cooled engine to circulate a coolant to the water-cooled engine and the heat exchanger;
• a temperature detector to detect a temperature of the coolant;
• and
• a controller that drivingly controls the pump on the basis of a detected value of the coolant temperature by the temperature detector in such a manner as to control the drive of the pump for the coolant to be circulated by a predetermined flow quantity, when the temperature of the coolant detected by the temperature detector indicates a value higher than a predetermined target temperature, the heat exchanger being arranged, at the predetermined flow quantity of the coolant, to cause Reynolds number of the coolant circulated within the tubes of the heat exchanger to fall in a range between 1800 and 6000.

A control method applicable to a control system for a water-cooled internal combustion engine, the control system comprising:

• a heat exchanger to circulate a coolant flowing out from the water-cooled engine into tubes arranged in a space between headers thereof to cool the coolant;
• a pump driven independently of the water-cooled engine to circulate the coolant to the water-cooled engine and the heat exchanger;
• and
• a temperature detector to detect a temperature of the coolant, the control method comprising:
• determining whether the temperature of the coolant detected by the temperature detector indicates a value higher than a predetermined target temperature;
• drivingly controlling the pump on the basis of a detected value of the coolant temperature by the temperature detector in such a manner as to control the drive of the pump for the coolant to be circulated by a predetermined flow quantity, when determining that the temperature of the coolant detected by the temperature detector indicates a value higher than a predetermined target temperature, at the predetermined flow quantity of the coolant;
• and
• causing a stream state of the coolant circulated within the tubes of the heat exchanger to fall within a predetermined range including at least one of a transition range between a laminar flow range and a turbulence flow range and a part of the turbulence flow range which is placed in vicinity to the transition range.