Refrigerator and control method thereof

Abstract

A refrigerator and a control method thereof in which a smooth flow of a refrigerant can be provided through an effective control for a path change valve when a flow path of the refrigerant is changed between two evaporators equipped in the refrigerator by the path change valve. The refrigerator includes a refrigerating compartment evaporator, a freezing compartment evaporator, a first expansion device adapted to expand a flow of a refrigerant to be introduced into the refrigerating compartment evaporator, a second expansion device adapted to expand a flow of the refrigerant to be introduced into the freezing compartment evaporator, a path change device adapted to change a flow path of the refrigerant between the first expansion device and the second expansion device, and a control unit adapted to control the path change device so that, when the refrigerant flow path is changed from the second expansion device to the first expansion device, a simultaneous opening stage causing the refrigerant to be introduced into both the first expansion device and the second expansion device is maintained for a predetermined time.

1 . A refrigerator comprising: 
 a refrigerating compartment evaporator;    a freezing compartment evaporator;    a first expansion device adapted to expand a flow of a refrigerant to be introduced into the refrigerating compartment evaporator;    a second expansion device adapted to expand a flow of the refrigerant to be introduced into the freezing compartment evaporator;    a path change device adapted to change a flow path of the refrigerant between the first expansion device and the second expansion device; and    a control unit adapted to control the path change device so that, when the refrigerant flow path is changed from the second expansion device to the first expansion device, a simultaneous opening stage causing the refrigerant to be introduced into both the first expansion device and the second expansion device is maintained for a predetermined time.    
   
   
       2 . The refrigerator according to  claim 1 , wherein: 
 the path change device comprises a 3-way valve adapted to change the refrigerant flow path in accordance with a rotation of a stepping motor; and    the control unit rotates the stepping motor to cause the refrigerant flow path to be changed from the second expansion device to the first expansion device, while temporarily stopping, for the predetermined time, the rotation of the stepping motor at a rotation angle thereof corresponding to the simultaneous opening stage.    
   
   
       3 . A method for controlling a refrigerator including a refrigerating compartment evaporator, a freezing compartment evaporator, a first expansion device adapted to expand a flow of a refrigerant to be introduced into the refrigerating compartment evaporator, a second expansion device adapted to expand a flow of the refrigerant to be introduced into the freezing compartment evaporator, and a path change device adapted to change a flow path of the refrigerant between the first expansion device and the second expansion device, the method comprising the step of: 
 controlling the path change device when the refrigerant flow path is changed from the second expansion device to the first expansion device so that a simultaneous opening stage causing the refrigerant to be introduced into both the first expansion device and the second expansion device is maintained for a predetermined time.    
   
   
       4 . The method according to  claim 3 , wherein: 
 the path change device is a 3-way valve adapted to change the refrigerant flow path in accordance with a rotation of a stepping motor; and    the step of controlling the path change device comprises the step of rotating the stepping motor to cause the refrigerant flow path to be changed from the second expansion device to the first expansion device, while temporarily stopping, for the predetermined time, the rotation of the stepping motor at a rotation angle thereof corresponding to the simultaneous opening stage.    
   
   
       5 . The method according to  claim 3 , further comprising the step of: 
 controlling the path change device when the refrigerant flow path is changed from the first expansion device to the second expansion device so that there is no time for maintaining the simultaneous opening stage causing the refrigerant to be introduced into both the first expansion device and the second expansion device.    
   
   
       6 . The method according to  claim 3 , wherein the predetermined time is longer than a time, for which the simultaneous opening stage causing the refrigerant to be introduced into both the first expansion device and the second expansion device is maintained due to mechanical characteristics of the path change valve when the refrigerant flow path is changed from the first expansion device to the second expansion device.