Control method for electric thermostat and control apparatus thereof

Abstract

Provided is a control method of an electric thermostat that can reduce cooling loss and friction loss of an engine by variably controlling opening/closing characteristic of the electric thermostat in accordance with metal surface temperature at a region with the maximum thermal load in the engine, can improve fuel efficiency by reducing the operation time and the number of operation times of a cooling fan of a radiator, and can improve heating performance for the interior of a vehicle.

1 . A control method of an electric thermostat, comprising the steps of:
 receiving that receives a metal surface temperature at a region with a maximum thermal load of an engine;   determining temperature that determines whether the metal surface temperature is within a plurality of temperature ranges that are sequentially set; and   activating a thermostat that supplies different voltage for controlling an electric thermostat in accordance with the temperature ranges in which the received metal surface temperature is, after the determining temperature.   
     
     
         2 . The method as defined in  claim 1 , wherein after the receiving step, the determining temperature step and the activating a thermostat step are alternately performed sequentially from the lower temperature range to the higher temperature range in the temperature ranges. 
     
     
         3 . The method as defined in  claim 1 , wherein after the receiving step, the determining temperature step and the activating a thermostat step are alternately performed sequentially from the higher temperature range to the lower temperature range in the temperature ranges. 
     
     
         4 . The method as defined in  claim 1 , wherein the electric thermostat is equipped with a heater and different voltages are supplied to the heater in accordance with the temperature range in which the received metal surface temperature is, in the activating a thermostat step. 
     
     
         5 . A control apparatus of an electric thermostat, comprising:
 a temperature input unit that receives the metal surface temperature at a region with the highest thermal load in an engine;   a temperature determining unit that determines that which one of the sequentially set temperature ranges the metal surface temperature inputted through the temperature input unit pertains to; and   a thermostat activating unit that supplies different voltage for controlling the electric thermostat.