Refrigerant cycle device with ejector

Abstract

A refrigerant cycle device having an ejector includes a first evaporator for evaporating refrigerant flowing out of the ejector, a first passage portion for guiding refrigerant to a refrigerant suction port of the ejector, a throttle unit located in the first passage portion, a second evaporator located in the first passage portion downstream of the throttle unit, a bypass passage portion for guiding hot gas refrigerant from a compressor into the second evaporator, a bypass opening and closing unit provided in the bypass passage portion. Furthermore, a second passage portion is branched from the bypass passage portion downstream of the bypass opening and closing unit, and a flow control unit is provided in the second passage portion to prevent a flow of refrigerant from the first evaporator to the second evaporator through the second passage portion. Therefore, defrosting of both the first and second evaporators can be suitably performed.

1 . A refrigerant cycle device comprising:
 a compressor that sucks in and compresses refrigerant;   a radiator located to cool high-pressure hot gas refrigerant discharged from the compressor;   an ejector that has a nozzle section for decompressing and expanding refrigerant downstream of the radiator, a refrigerant suction port for sucking in refrigerant by a high-speed flow of refrigerant jetted from the nozzle section, and a pressurizing section for mixing and pressurizing the refrigerant jetted at high speed and the refrigerant sucked through the refrigerant suction port;   a first evaporator for evaporating refrigerant flowing out of the ejector;   a first passage portion for guiding refrigerant to the refrigerant suction port;   a throttle unit that is located in the first passage portion and decompresses the refrigerant flowing in the first passage portion;   a second evaporator that is located in the first passage portion downstream of the throttle unit in a refrigerant flow to evaporate refrigerant;   a bypass passage portion for guiding the hot gas refrigerant discharged from the compressor into the second evaporator;   a bypass opening and closing unit that is provided in the bypass passage portion to open and close the bypass passage portion, the bypass opening and closing unit having a throttling open degree when being opened;   a second passage portion that is branched from the bypass passage portion downstream of the bypass opening and closing unit in a refrigerant flow, wherein the hot gas refrigerant in the bypass passage portion flows to the first evaporator through the second passage portion; and   a first flow control unit that is provided in the second passage portion to prevent a flow of refrigerant from a side of the first evaporator to a side of the second evaporator through the second passage portion.   
   
   
       2 . The refrigerant cycle device according to  claim 1 ,
 wherein the first passage portion is a branch passage branched from an upstream side of the nozzle section of the ejector in a refrigerant flow from the radiator, to guide the refrigerant from the radiator to the refrigerant suction port of the ejector.   
   
   
       3 . The refrigerant cycle device according to  claim 1 , further comprising
 a gas-liquid separator that separates refrigerant flowing out of the first evaporator into vapor refrigerant and liquid refrigerant, collects the liquid refrigerant therein, and guides the vapor refrigerant out to a refrigerant suction side of the compressor,   wherein the first passage portion is a connection passage that connects a liquid refrigerant outlet portion of the gas-liquid separator to the refrigerant suction port.   
   
   
       4 . The refrigerant cycle device according to  claim 1 ,
 wherein the first flow control unit is a check valve, which is located to only permit a flow of refrigerant from the bypass passage portion to the first evaporator through the second passage portion.   
   
   
       5 . The refrigerant cycle device according to  claim 1 ,
 wherein the first flow control unit is a switching valve that located to open and close the second passage portion.   
   
   
       6 . The refrigerant cycle device according to  claim 5 ,
 wherein the switching valve is opened when the bypass opening and closing unit is opened, and is closed when the bypass opening and closing unit is closed.   
   
   
       7 . The refrigerant cycle device according to  claim 1 ,
 wherein the first flow control unit is a flow adjusting valve that is located to be brought into a closed state and to regulate a flow amount of refrigerant in accordance with its valve open degree that is adjustable.   
   
   
       8 . The refrigerant cycle device according to  claim 7 , further comprising:
 an inlet-side temperature detector that is located to directly or indirectly detect a refrigerant temperature at a refrigerant inlet side of the first evaporator; and   an outlet-side temperature detector that is located to directly or indirectly detect a refrigerant temperature at a refrigerant outlet side of the second evaporator, wherein   the flow adjusting valve is brought into the closed state when the bypass opening and closing unit is closed, and   when the bypass opening and closing unit is opened, the flow adjusting valve increases its valve open degree more as the refrigerant temperature detected by the inlet-side temperature detector is lower than the refrigerant temperature detected by the outlet-side temperature detector, and the flow adjusting valve decreases its valve open degree more as the refrigerant temperature detected by the inlet-side temperature detector is higher than the refrigerant temperature detected by the outlet-side temperature detector.   
   
   
       9 . The refrigerant cycle device according to  claim 1 , further comprising:
 a third passage portion that is branched from the first passage portion at a position downstream of the second evaporator in a flow of refrigerant from the second evaporator, to guide the flow of the refrigerant from the second evaporator to the first evaporator; and   a second flow control unit that is located in the third passage portion to prevent a flow of refrigerant from the first evaporator to the second evaporator through the third passage portion.   
   
   
       10 . The refrigerant cycle device according to  claim 9 ,
 wherein the second flow control unit is a check valve, which is located to only permit a flow of refrigerant from the second evaporator to the first evaporator through the third passage portion.   
   
   
       11 . The refrigerant cycle device according to  claim 9 ,
 wherein the second flow control unit is a switching valve that is located to open and close the third passage portion.   
   
   
       12 . The refrigerant cycle device according to  claim 11 ,
 wherein the switching valve is opened when the bypass opening and closing unit is opened, and is closed when the bypass opening and closing unit is closed.   
   
   
       13 . The refrigerant cycle device according to  claim 9 ,
 wherein the second flow control unit is a flow adjusting valve that is located to be brought into a closed state and to regulate a flow amount of refrigerant in accordance with its valve open degree that is adjustable   
   
   
       14 . The refrigerant cycle device according to  claim 1 , further comprising
 a passage opening and closing unit located to open and close a refrigerant passage connected to a refrigerant inlet or a refrigerant outlet of the radiator,   wherein the passage opening and closing unit is closed when the bypass opening and closing unit is opened.   
   
   
       15 . The refrigerant cycle device according to  claim 3 , further comprising:
 a throttle opening and closing unit located in the connection passage to open and close a refrigerant passage connected to a refrigerant inlet or a refrigerant outlet of the throttle unit,   wherein the throttle opening and closing unit is closed when the bypass opening and closing unit is opened.   
   
   
       16 . The refrigerant cycle device according to  claim 1 ,
 wherein the first evaporator and the second evaporator are constituted such that a flow resistance of refrigerant flowing in the second evaporator is greater than that of refrigerant flowing in the first evaporator.   
   
   
       17 . A refrigerant cycle device comprising:
 a compressor that sucks in and compresses refrigerant;   a radiator located to cool high-pressure hot gas refrigerant discharged from the compressor;   an ejector that has a nozzle section for decompressing and expanding refrigerant downstream of the radiator, and a refrigerant suction port for sucking in refrigerant by a high-speed flow of refrigerant jetted from the nozzle section;   a first evaporator for evaporating refrigerant flowing out of the ejector;   a branch passage portion branched from an upstream side of the nozzle section and joined to the refrigerant suction port of the ejector;   a throttle unit that is located in the branch passage portion and decompresses the refrigerant flowing in the branch passage portion;   a second evaporator that is located in the branch passage portion downstream of the throttle unit in a refrigerant flow;   a bypass passage portion for guiding the hot gas refrigerant discharged from the compressor into the second evaporator; and   a bypass opening and closing unit that is located in the bypass passage portion to open and close the bypass passage portion,   wherein the first evaporator and the second evaporator are constituted such that a flow resistance of refrigerant flowing in the second evaporator is greater than that of refrigerant flowing in the first evaporator.   
   
   
       18 . The refrigerant cycle device according to  claim 17 , wherein:
 the first evaporator includes a plurality of first tubes in which refrigerant flows;   the second evaporator includes a plurality of second tubes in which refrigerant flows;   each first tube and each second tube are identical in a passage sectional area therein; and   the second tubes of the second evaporator have a tube number that is smaller than that of the first tubes of the first evaporator.   
   
   
       19 . The refrigerant cycle device according to  claim 17 , wherein:
 the first evaporator includes a plurality of first tubes in which refrigerant flows;   the second evaporator includes a plurality of second tubes in which refrigerant flows;   the first tubes of the first evaporator and the second tubes of the second evaporator are identical in a tube length; and   each of the second tubes of the second evaporator has therein a passage sectional area that is smaller than that of each first tube of the first evaporator.   
   
   
       20 . The refrigerant cycle device according to  claim 17 , wherein:
 the first evaporator includes a plurality of first tubes in which refrigerant flows;   the second evaporator includes a plurality of second tubes in which refrigerant flows;   each first tube of the first evaporator and each second tube of the second evaporator are identical in a passage sectional area therein; and   each of the second tubes of the second evaporator has a tube length that is larger than that of the first tubes of the first evaporator.   
   
   
       21 . The refrigerant cycle device according to  claim 17 , wherein:
 the first evaporator includes a plurality of first tubes in which refrigerant flows;   the second evaporator includes a plurality of second tubes in which refrigerant flows;   each first tube of the first evaporator and each second tube of the second evaporator are identical in a passage sectional area therein; and   wherein the second tubes of the second evaporator have therein grooved passages, and the second tubes of the first evaporator have therein flat passages.   
   
   
       22 . The refrigerant cycle device according to  claim 17 , wherein the bypass opening and closing unit opens the bypass passage portion in a defrosting mode where a defrosting operation of at least the second evaporator is performed.