Patent ID: 7011050
Filing Date: 2006-03-14
Classification: F01P

Abstract:
1. A method for controlling an electronically controlled thermostat provided in a cooling system of an internal combustion engine, the method comprising: predicting a thermal radiation amount of a radiator when a water temperature of engine cooling water is stabilized at a second set temperature without detecting the water temperature not to cause temperature hunting, when the water temperature is controlled from a first set temperature to the second set temperature lower than the first set temperature; controlling the electronically controlled thermostat to control the water temperature in accordance with the predicted thermal radiation amount; calculating a heat generation amount of the internal combustion engine; correcting the control of the electronically controlled thermostat to match fluctuations in the heat generation amount and the thermal radiation amount of the radiator; calculating a flow rate of the engine cooling water based on a rotation speed of a water pump; correcting the control of the electronically controlled thermostat to cancel fluctuations in the flow rate caused by fluctuations in the rotation speed; calculating an outlet water temperature at an outlet of the radiator; correcting the control of the electronically controlled thermostat to cancel fluctuations in a thermal radiation capacity caused by fluctuations in the outlet water temperature; calculating an opening ratio of a valve of the electronically controlled thermostat based on the flow rate; and correcting the control of the electronically controlled thermostat to cancel a nonlinear characteristic of the valve.