Control method for engine thermal management

Abstract

A control method for engine thermal management that provides an electronic fan clutch and an electronic water pump in cooperation with an operation of an electronic thermostat, thereby achieving efficient engine thermal management and reducing a loss of load. The control method includes the steps of obtaining an engine coolant temperature and engine driving information and calculating a required fan rotational speed based on the obtained current coolant temperature information and the obtained engine driving information. The method calculates a control value for controlling a rotational speed of a cooling fan and checks a current operating state of the electronic thermostat. The method determines whether to operate the electronic water pump and control the cooling fan rotational speed based on the checked current operating state of the electronic thermostat, and controls the electronic water pump and the electronic fan clutch of the cooling fan based on the determination result.

What is claimed is: 
     
         1 . A control method for engine thermal management, the control method comprising:
 obtaining an engine coolant temperature and engine driving information;   calculating a required fan rotational speed based on the obtained current coolant temperature information and the obtained engine driving information;   calculating a control value for controlling a rotational speed of a cooling fan having an electronic fan clutch so that the rotational speed becomes the required fan rotational speed;   checking a current operating state of an electronic thermostat; and   determining whether to operate an electronic water pump and whether to control the cooling fan rotational speed using the control value based on the checked current operating state of the electronic thermostat, and controlling the electronic water pump and the electronic fan clutch of the cooling fan based on the determination result.   
     
     
         2 . The control method of  claim 1 , wherein when the electronic thermostat is in a closed state after the checking of the current operating state of the electronic thermostat, the electronic water pump is controlled to be in a slip state. 
     
     
         3 . The control method of  claim 2 , wherein fan clutch control for rotating the cooling fan at an idle rotational speed is carried out in the slip state of the electronic water pump. 
     
     
         4 . The control method of  claim 1 , wherein when the electronic thermostat is in an opened state after the checking of the current operating state of the electronic thermostat, an operation of the electronic water pump is controlled based on the coolant temperature and the engine driving information. 
     
     
         5 . The control method of  claim 4 , wherein when the current engine coolant temperature is lower than a predetermined minimum fan operation coolant temperature or the current operating state of the electronic water pump is in a state in which the operation of the electronic water pump is controlled to be in a slip state, fan clutch control for rotating the cooling fan at an idle rotational speed is carried out. 
     
     
         6 . The control method of  claim 4 , wherein when the current coolant temperature is equal to or higher than a minimum fan operation coolant temperature and the current operating state of the electronic water pump is in a state in which the operation of the electronic water pump is controlled to not be in a slip state, the operation of the electronic fan clutch is controlled in accordance with a control value for controlling the cooling fan so that the rotational speed of the cooling fan becomes the required fan rotational speed. 
     
     
         7 . The control method of  claim 1 , wherein the electronic thermostat is controlled based on the current engine coolant temperature and engine torque by using a map in which opening/closing operation regions are set in accordance with the engine coolant temperature and the engine torque. 
     
     
         8 . The control method of  claim 7 , wherein the operation region is set in the map so that an operation of opening the electronic thermostat is carried out under a condition of the engine coolant temperature and the engine torque that are lower, by predetermined set values, than an engine coolant temperature and engine torque at which the electronic water pump is operated. 
     
     
         9 . The control method of  claim 1 , wherein the electronic thermostat is controlled based on the current engine coolant temperature, engine torque, and a vehicle speed by using a map in which opening/closing operation regions are set in accordance with the engine coolant temperature, the engine torque, and the vehicle speed. 
     
     
         10 . The control method of  claim 9 , wherein the operation region is set in the map so that an operation of opening the electronic thermostat is carried out under a condition of the engine coolant temperature and the engine torque that are lower, by predetermined set values, than an engine coolant temperature and engine torque at which the electronic water pump is operated. 
     
     
         11 . The control method of  claim 1 , wherein an operation of the electronic water pump and an operation of the electronic thermostat are carried out in cooperation with each other, such that the electronic thermostat is controlled to an opened state when the electronic water pump is operated, and the electronic thermostat is controlled to a closed state when the electronic water pump is in a slip state. 
     
     
         12 . The control method of  claim 1 , wherein operations of the electronic thermostat and the electronic water pump are carried out in cooperation with an operation of a retarder, such that when the retarder is operated, the electronic thermostat is controlled to an opened state, and the electronic water pump is fully operated to a state of a slip rate of 0%. 
     
     
         13 . The control method of  claim 1 , wherein operations of the electronic thermostat and the electronic water pump are carried out in cooperation with an operation of a retarder, such that when a condition of the engine coolant temperature and an engine driving condition correspond to a condition in which the electronic thermostat is closed and the electronic water pump is turned off at a point of time at which the retarder is turned off, the opened state of the electronic thermostat and the operating state of the electronic water pump are maintained for a predetermined time from a point of time at which the retarder is turned off, and after the predetermined time has passed, the electronic thermostat is controlled to be closed and the water pump is controlled to be turned off. 
     
     
         14 . The control method of  claim 1 , wherein the electronic thermostat is controlled to be fully opened when at least one of the electronic fan clutch of the cooling fan and the electronic water pump is abnormally operated.