| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an engine cooling system capable of preventing the deterioration of fuel consumption as compared with a conventional one.SOLUTION: An engine cooling system is equipped with a cooling circuit 9 in which cooling water 8 circulates in a radiator 3, a water pump 4, an engine body 5, a thermostat 6, and a water-cooling type EGR cooler 7 which are annularly connected; and a cooling fan 10 which uses the engine body 5 as a driving source. In the cooling circuit 9 on a downstream side of the EGR cooler 7, first channel switching means 24 capable of branching off to the radiator 3 is installed. Between the first channel switching means 24 and the radiator 3, second channel switching means 26 capable of branching off to a sub radiator 25 is installed. The first channel switching means 24 switches a channel to the radiator 3 when the temperature of cooling water 8a exceeds first threshold temperature X, and the second channel switching means 26 switches the channel to the sub radiator 25, when the temperature of the cooling water 8a exceeds the threshold temperature X and exceeds threshold temperature Y which is lower than the valve-opening temperature S of the thermostat 6.</p> |
