Method of determining circulation state of cooling water

Abstract

A method of determining a state of cooling water is provided. The method includes operating, by a controller, a driving motor of a cooling water-circulating pump that is configured to circulate cooling water at a fixed current, a fixed torque, or a fixed power. In addition, the controller is configured to calculate an average rotation speed of the driving motor for a preset first period of time during the operation of the driving motor. Whether the circulation state of the cooling water is normal is determined based on an error between the calculated average rotation speed and a preset reference rotation speed.

What is claimed is: 
     
         1 . A method of determining a circulation state of cooling water, comprising:
 operating, by a controller, a driving motor of a cooling water-circulating pump configured to circulate cooling water at a fixed current, a fixed torque, or a fixed power;   calculating, by the controller, an average rotation speed of the driving motor for a preset first period of time during the operation of the driving motor; and   determining, by the controller, whether the circulation state of the cooling water is normal, based on an error between the calculated average rotation speed and a preset reference rotation speed.   
     
     
         2 . The method according to  claim 1 , wherein the calculation of the average rotation speed includes:
 calculating, by the controller, a deviation in rotation speed of the driving motor for the preset first period of time.   
     
     
         3 . The method according to  claim 2 , wherein the determination of the circulation state of the cooling water includes:
 determining, by the controller, whether the circulation state of the cooling water is normal by comparing a deviation in the calculated average rotation speed and a preset reference deviation.   
     
     
         4 . The method according to  claim 1 , wherein the preset reference rotation speed is a rotation speed of the driving motor that corresponds to the fixed current, the fixed torque, or the fixed power. 
     
     
         5 . A method of determining a circulation state of cooling water, comprising:
 operating, by a controller, a driving motor disposed in a pump for circulating a cooling water to adjust a rotation speed of the driving motor to be substantially constant; and   determining, by the controller, whether a circulation state of the cooling water is normal using a power or torque value of the driving motor obtained after the rotation speed of the driving motor is adjusted to be substantially constant and a reference power or torque value during a normal state that corresponds to the substantially constant rotation speed.   
     
     
         6 . The method according to  claim 5 , wherein the power or torque value of the driving motor, and the reference power or torque value of the driving motor when the driving motor rotates at the rotation speed are each obtained substantially constant using a current command value transmitted to the driving motor and a current command value during the normal state that corresponds to the substantially constant rotation speed. 
     
     
         7 . The method according to  claim 6 , wherein the determination of the circulation state of the cooling water includes:
 calculating, by the controller, an average value of the current command values transmitted to the driving motor for a first period of time after the rotation speed of the driving motor is adjusted to be substantially constant; and   determining, by the controller, whether the circulation state of the cooling water is normal, based on an error between the calculated average value and the current command value during the normal state that corresponds to the substantially constant rotation speed.   
     
     
         8 . The method according to  claim 7 , wherein the determination of the circulation state of the cooling water includes:
 normalizing, by the controller, by dividing the calculated average value by the current command value during the normal state that corresponds to the substantially constant rotation speed.   
     
     
         9 . The method according to  claim 7 , further comprising:
 determining, by the controller, that the circulation state of the cooling water is abnormal when a state when the error exceeds a preset error reference value is maintained for a second period of time.   
     
     
         10 . The method according to  claim 7 , further comprising:
 enabling, by the controller, a test mode when the error exceeds a preset error reference value.   
     
     
         11 . The method according to  claim 10 , further comprising in the test mode:
 determining, by the controller, that the circulation state of the cooling water is abnormal, when a state when an error between the calculated average value and the current command value used when the driving motor rotates at a maximum rotation speed in the test mode exceeds the error reference value is maintained for a preset second period of time.   
     
     
         12 . The method according to  claim 10 , wherein the error reference value varies according to the rotation speed of the driving motor. 
     
     
         13 . The method according to  claim 10 , wherein the driving motor is maintained at a maximum rotation speed, when the test mode is enabled. 
     
     
         14 . The method according to  claim 6 , wherein the current command value that corresponds to the rotation speed is obtained using a preset current command map based on the rotation speed. 
     
     
         15 . The method according to  claim 6 , wherein the determination of the circulation state of the cooling water includes:
 calculating, by the controller, a deviation or a variation value in the current command value for the first period of time; and   determining, by the controller, whether the circulation state of the cooling water is normal, based on a result of a comparison between the calculated deviation or variation value and a preset reference value.   
     
     
         16 . The method according to  claim 15 , further comprising:
 determining, by the controller, that the circulation state of the cooling water is abnormal, when a state where the calculated deviation or variation value exceeds the preset reference value is maintained for a second period of time.   
     
     
         17 . The method according to  claim 15 , wherein a test mode is enabled, when the calculated deviation or variation value exceeds the preset reference value. 
     
     
         18 . The method according to  claim 17 , wherein the driving motor is maintained at a maximum rotation speed when the test mode is enabled. 
     
     
         19 . The method according to  claim 6 , wherein the determination of the circulation state of the cooling water includes:
 integrating, by the controller, an error between the current command value that corresponds to the rotation speed and the current command value transmitted to the driving motor; and   determining, by the controller, whether the circulation state of the cooling water is normal, based on a result of a comparison between the value of the integral operation and a preset reference value.   
     
     
         20 . The method according to  claim 19 , further comprising:
 normalizing, by the controller, by dividing the calculated average value by the current command value during the normal state that corresponds to the rotation speed.   
     
     
         21 . The method according to  claim 19 , further comprising:
 determining, by the controller, that the circulation state of the cooling water is abnormal, when a state where the value of the integral operation exceeds the preset reference value is maintained for a second period of time.   
     
     
         22 . The method according to  claim 19 , wherein a test mode is enabled when the value of the integral operation exceeds the reference value. 
     
     
         23 . The method according to  claim 22 , wherein the driving motor is maintained at a maximum rotation speed when the test mode is enabled. 
     
     
         24 . A method of determining a circulation state of cooling water, comprising:
 maintaining, by the controller, a constant rotation speed of a driving motor of a cooling water-circulating pump configured to circulate cooling water; and   enabling, by the controller, a test mode when an error between a power or torque value of the driving motor after the rotation speed is maintained substantially constant and a reference power or torque value during a normal state that corresponds to the rotation speed maintained substantially constant is occurred.   
     
     
         25 . The method according to  claim 24 , further comprising in the test mode:
 determining, by the controller, whether the circulation state of the cooling water is normal, in a state when the driving motor rotates at a maximum rotation speed.