| 摘要 |
<p>When a vehicle is driven under a high load immediately after a start-up of an engine (1) from a cold state, coolant retained in a cylinder head receives heat from a combustion chamber while passage of coolant inside the engine (1) is prohibited by a closed thermostat (7). This may cause the coolant to boil. However, the thermostat (7) includes a valve body (22) that is forced to open when the discharge flow rate of a water pump (3) is increased compared with a flow rate within a normal use range, and the valve body (22) can be responsively opened by increasing the discharge flow rate of the water pump (3) compared with the flow rate within the normal use range in the above-described situation so that coolant quickly flows into the inside of the engine (1). With this, the coolant retained in the cylinder head before the opening operation of the valve body (22) is finished can be prevented from boiling.</p> |
