Ejector refrigerant cycle device and control method thereof

Abstract

An ejector refrigerant cycle device includes an ejector that has a nozzle portion for reducing pressure of refrigerant on a downstream side of a radiator to expand the refrigerant, and a refrigerant suction port from which refrigerant is drawn by a high-velocity refrigerant flow jetted from the nozzle portion, an evaporator that evaporates refrigerant and flows out the evaporated refrigerant to the refrigerant suction port, a flow amount changing unit that changes a refrigerant flow amount flowing into the evaporator, and a pressure abnormality detecting portion for detecting a pressure abnormality of a high-pressure refrigerant on an upstream side of the nozzle portion. In the ejector refrigerant cycle device, when the pressure abnormality detecting portion detects the pressure abnormality, the flow amount changing unit makes the refrigerant flow amount flowing into the evaporator larger than that in a normal pressure state of the high-pressure refrigerant.

1 . An ejector refrigerant cycle device comprising: 
 a compressor that draws, compresses and discharges refrigerant;    a radiator that radiates heat of refrigerant discharged from the compressor;    an ejector that has a nozzle portion for reducing pressure of refrigerant on a downstream side of the radiator to expand the refrigerant, and a refrigerant suction port from which refrigerant is drawn by a high-velocity refrigerant flow jetted from the nozzle portion, wherein the ejector mixes refrigerant drawn from the refrigerant suction port and refrigerant jetted from the nozzle portion, and reduces the velocity of the mixed refrigerant so as to increase its pressure;    an evaporator that evaporates refrigerant and flows out the evaporated refrigerant to the refrigerant suction port;    a flow amount changing unit that changes a refrigerant flow amount flowing into the evaporator; and    a pressure abnormality detecting means that detects a pressure abnormality of a high-pressure refrigerant on an upstream side of the nozzle portion,    wherein the compressor draws refrigerant on a downstream side of the ejector, and    wherein when the pressure abnormality detecting means detects the pressure abnormality, the flow amount changing unit makes the refrigerant flow amount flowing into the evaporator larger than that in a normal pressure state of the high-pressure refrigerant.    
   
   
       2 . The ejector refrigerant cycle device as in  claim 1 , further comprising: 
 an accumulator that separates refrigerant flowing out of the ejector into vapor refrigerant and liquid refrigerant; and    a liquid refrigerant passage through which the liquid refrigerant flows from the accumulator into the evaporator,    wherein the flow amount changing unit is arranged in the liquid refrigerant passage.    
   
   
       3 . The ejector refrigerant cycle device as in  claim 1 , further comprising: 
 a branch passage branched from a point between a downstream side of the radiator and an upstream side of the nozzle portion, and is joined to the refrigerant suction port of the ejector,    wherein the flow amount changing unit is arranged in the branch passage.    
   
   
       4 . The ejector refrigerant cycle device as in  claim 1 , 
 wherein when a high-pressure refrigerant pressure on the upstream side of the nozzle portion becomes not less than a predetermined value, the pressure abnormality detecting means detects the pressure abnormality.    
   
   
       5 . The ejector refrigerant cycle device as in  claim 1 , 
 wherein when a pressure-increase amount per unit time of the high-pressure refrigerant on the upstream side of the nozzle portion becomes not less than a predetermined amount, the pressure abnormality detecting means detects the pressure abnormality.    
   
   
       6 . The ejector refrigerant cycle device as in  claim 1 , 
 wherein the flow amount changing unit is a variable throttle mechanism that is constructed to change an area of a refrigerant passage.    
   
   
       7 . The ejector refrigerant cycle device as in  claim 1 , further comprising: 
 a drive member that drives the flow amount changing unit to change a refrigerant passage area in the flow amount changing unit; and    a control unit that controls operation of the drive member,    wherein the pressure abnormality detecting means includes a pressure sensor for detecting a pressure of high-pressure refrigerant on the upstream side of the nozzle portion, and determination means that determines whether or not a detection value of the pressure sensor corresponds to the pressure abnormality, and    wherein when the determination means determines that the detection value of the pressure sensor corresponds to the pressure abnormality, the control unit controls the drive member so as to expand the refrigerant passage area.    
   
   
       8 . The ejector refrigerant cycle device as in  claim 1 , wherein the ejector further includes a mixing portion in which the refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed, and a diffuser portion which increases pressure of the mixed refrigerant from the mixing portion, the device further comprising 
 reducing means for reducing a pressure increasing amount of the mixed refrigerant in the diffuser portion,    wherein when the pressure abnormality detecting means detects the pressure abnormality, the reducing means reduces the pressure increasing amount of the mixed refrigerant in the diffuser portion than that in the normal pressure state of the high-pressure refrigerant.    
   
   
       9 . The ejector refrigerant cycle device as in  claim 8 , wherein the flow amount changing unit is used as the reducing means.  
   
   
       10 . The ejector refrigerant cycle device according to  claim 3 , further comprising 
 an another evaporator for evaporating refrigerant flowing out of an outlet port of the ejector.    
   
   
       11 . An ejector refrigerant cycle device comprising: 
 a compressor that draws, compresses and discharges refrigerant;    a radiator that radiates heat of refrigerant discharged from the compressor;    an ejector that has a nozzle portion for reducing pressure of refrigerant on a downstream side of the radiator to expand the refrigerant, a refrigerant suction port from which refrigerant is drawn by a high-velocity refrigerant flow jetted from the nozzle portion, a mixing portion in which the refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed, and a diffuser portion which increases pressure of the mixed refrigerant from the mixing portion;    an evaporator that evaporates refrigerant and flows out the evaporated refrigerant to the refrigerant suction port;    a pressure abnormality detecting means that detects a pressure abnormality of a high-pressure refrigerant on an upstream side of the nozzle portion; and    reducing means for reducing a pressure increasing amount of the mixed refrigerant in the diffuser portion of the ejector,    wherein the compressor draws refrigerant on a downstream side of the ejector, and    wherein when the pressure abnormality detecting means detects the pressure abnormality, the reducing means reduces a pressure increasing amount of the mixed refrigerant in the diffuser portion than that in a normal pressure state of the high-pressure refrigerant.    
   
   
       12 . The ejector refrigerant cycle device according to  claim 11 , wherein the pressure abnormality detecting means detects the pressure abnormality when the pressure of refrigerant at the upstream side of the nozzle portion is higher than a predetermined amount.  
   
   
       13 . A control method of an ejector refrigerant cycle device having an ejector that includes a nozzle portion for reducing pressure of a high-pressure refrigerant, a refrigerant suction port from which refrigerant from an evaporator is drawn by a high-velocity refrigerant flow jetted from the nozzle portion, a mixing portion in which the refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed, and a diffuser portion which increases pressure of the mixed refrigerant from the mixing portion, the control method comprising: 
 detecting a pressure abnormality of the high-pressure refrigerant on an upstream side of the nozzle portion; and    reducing a pressure increasing amount of the mixed refrigerant in the diffuser portion than that in a normal pressure state of the high-pressure refrigerant.    
   
   
       14 . The control method according to  claim 13 , wherein 
 the reducing is performed by increasing a refrigerant amount flowing into the evaporator, which has a refrigerant outlet coupled to the refrigerant suction port of the ejector, to be larger than that in the normal pressure state of the high-pressure refrigerant.