JP4784418B2 - Ejector refrigeration cycle and evaporator unit - Google Patents

Description

  The present invention relates to an ejector refrigeration cycle having an ejector serving as a refrigerant decompression unit and a refrigerant circulation unit, and a plurality of evaporators, and an evaporator unit used in the ejector refrigeration cycle.

  Conventionally, this type of ejector refrigeration cycle is known from Patent Documents 1 and 2 listed below. For example, in Patent Document 1, the pressure of the refrigerant rises by evaporating the refrigerant exiting the throttling mechanism with a second evaporator and sucking the evaporated refrigerant into an ejector. Then, the refrigerant exiting the ejector is evaporated by the first evaporator and then sucked into the compressor.

  Since the evaporation temperature of the second evaporator becomes lower than the evaporation temperature of the first evaporator due to the boosting effect of the ejector, the temperature difference with the fluid to be cooled (for example, air) becomes large, and the cooling performance is improved. Note that the amount of pressure increase in the ejector varies depending on the ratio of the suction refrigerant flow rate of the ejector to the drive refrigerant flow rate entering the nozzle and the state of each refrigerant.

Further, when the ejector and the second evaporator of the ejector suction refrigerant are separated from each other, or when the ejector and the first evaporator of the ejector discharge refrigerant are separated from each other, pressure loss occurs in the refrigerant flow, and the boosting effect of the ejector is generated. Therefore, it is desirable to dispose the ejector at a position closest to the first and second evaporators. Therefore, in Patent Document 3 below, the ejector and the first and second evaporators are integrated, so that the ejector is arranged in the vicinity of the entrances of the first and second evaporators.
JP 2005-308384 A JP 2005-308380 A Japanese Patent No. 3265649

  However, when the ejector is disposed in the header tank portion or the like in the vicinity of the inlet / outlet of the first and second evaporators, the refrigerant flow passage cross-sectional area decreases and the refrigerant mass flow rate (the refrigerant mass flow rate refers to the header tank portion, the tube, etc. In each part of the refrigerant flow, the refrigerant mass flow rate is a value obtained by dividing the refrigerant mass flow rate by the refrigerant flow path cross-sectional area. Therefore, there is a problem that the pressure loss increases and the effect of improving the cooling performance decreases.

  In order to reduce this pressure loss, the refrigerant mass flow velocity can be reduced by setting each refrigerant channel cross-sectional area to a large value or by setting the refrigerant channel length to a short value. However, it is difficult to optimally set the channel cross-sectional area and the channel length.

  An object of the present invention is to clarify an allowable range of the pressure loss of the evaporator in an ejector-type refrigeration cycle in which an evaporator having a predetermined pressure loss is arranged on at least one of the suction side and the outflow side of the ejector. It is an object of the present invention to provide an evaporator unit capable of increasing the effective flow path cross-sectional area so that the pressure loss is within an allowable range.

In order to achieve the above object, the present invention employs technical means described in claims 1 to 7 .
That is, in the first aspect of the invention, the first evaporator (15) having a predetermined pressure loss is arranged on the outflow side of the ejector (14), and the second evaporator (18) having the predetermined pressure loss is provided. In the ejector-type refrigeration cycle disposed on the suction side of the ejector (14), the refrigerant branch passage is branched from the inlet side of the ejector , and the downstream side of the refrigerant branch passage is connected to the refrigerant suction port of the ejector. A second evaporator is arranged and the system is set so that the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is smaller than the pressure increase (PE) by the ejector (14) when the system is at a maximum load condition. The pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is set to be smaller than the pressure increase amount (PE) by the ejector (14) when the system is at the maximum load condition. In addition, the refrigerant pressure loss (ΔP2) in the second evaporator (18) is less than the refrigerant pressure loss (ΔP1) in the first evaporator (15) when the system is at the maximum load condition. An evaporator (15) and a second evaporator (18) are set .

According to this invention , the pressure loss (ΔP2) of the second evaporator (18) arranged on the suction side is made smaller than the pressure increase amount (PE) by the ejector (14) (assuming ΔP2 <PE), The average evaporation temperature in the second evaporator (18) can be made lower than in the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

According to the present invention , the pressure loss (ΔP1) of the first evaporator (15) arranged on the outflow side is made smaller than the pressure increase amount (PE) by the ejector (14) (assuming ΔP1 <PE) . Even when the pressure loss coefficient of one evaporator (15) is larger than that of the conventional evaporator, the average evaporation temperature in the first evaporator (15) on the outflow side can be made lower than that of the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

According to this invention , the pressure loss (ΔP2) of the second evaporator (18) arranged on the suction side is made smaller than the pressure loss (ΔP1) of the first evaporator (15) arranged on the outflow side (ΔP2). By making <ΔP1), it becomes possible to make the average evaporation temperature of the second evaporator (18) arranged on the suction side lower than that of the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

Further, the invention according to claim 2 further includes inlet throttle mechanisms (14a, 17) of the first evaporator (15) and the second evaporator (18), respectively, and the outlet of the second evaporator (18). The inlet throttling mechanism (14a, 17) is set so that the refrigerant pressure (Po2) is equal to or lower than the refrigerant pressure (Po1) at the outlet of the first evaporator (15).

According to this invention , since the ejector outflow refrigerant amount is larger than the ejector intake refrigerant amount, the first evaporator (15) in which the average evaporation temperature of the second evaporator (18) disposed on the intake side is disposed on the outflow side. It becomes possible to make it lower than the average evaporation temperature. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

In the invention according to claim 3 , the refrigerant is sucked from the refrigerant suction port (14b) by the high-speed refrigerant flow injected from the nozzle part (14a), and the refrigerant and the refrigerant injected from the nozzle part (14a) An ejector (14) that mixes and discharges the refrigerant sucked from the suction port (14b) , a first evaporator (15) that is disposed on the outflow side of the ejector (14) and has a predetermined pressure loss, and an ejector The second evaporator (18) having a predetermined pressure loss is disposed on the suction side of (14) , and the first evaporator (15), the second evaporator (18), and the ejector (14) are integrated. In the evaporator unit (20) assembled to the refrigerant, the refrigerant branch passage is branched from the inlet side of the ejector, the downstream side of the refrigerant branch passage is connected to the refrigerant suction port of the ejector, and the second evaporator is provided in the refrigerant branch passage. Placed Thus, when the system is at the maximum load condition, the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is set to be smaller than the pressure increase amount (PE) by the ejector (14), and the system is at the maximum load condition. Sometimes, the pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is set to be smaller than the pressure increase (PE) by the ejector (14), and the second evaporator is in the maximum load condition. The first evaporator (15) and the second evaporator (18) are set so that the refrigerant pressure loss (ΔP2) in (18) is less than the refrigerant pressure loss (ΔP1) in the first evaporator (15). Furthermore, the tip shape of the tube (21) inserted into the header tank portions (15b, 15c, 18b, 18c) of the first evaporator (15) and the second evaporator (18) However, in the width direction of the tube (21), it is characterized by a shape in which the central portion is recessed with respect to both end portions.

According to the present invention , it is possible to increase the refrigerant flow path cross-sectional area in the header tank portion (15b, 15c, 18b, 18c), and the refrigerant of the first evaporator (15) and the second evaporator (18) . Since the pressure loss can be reduced, the cooling performance can be improved.

Moreover, in invention of Claim 4 , in the evaporator unit of Claim 3 , the tip shape of the tube (21) is an ejector disposed in the header tank portion (15b, 15c, 18b, 18c) ( It is characterized by being formed along the outer shape of 14).

Further, in the invention according to claim 5 , in the evaporator unit according to claim 3 , the tip shape of the tube (21) is the inner shape of the header tank portion (15b, 15c, 18b, 18c) on the tube insertion side. It is formed so that it may follow.

According to the invention described in claim 4 or claim 5 , the tip shape of the tube (21) is changed to the outer shape of the ejector (14) or the tube insertion side of the header tank portion (15b, 15c, 18b, 18c). By forming so as to conform to the inner surface shape, it is possible to efficiently increase the refrigerant flow path cross-sectional area in the header tank portion (15b, 15c, 18b, 18c).

In the invention according to claim 6 , the refrigerant and the refrigerant injected from the nozzle part (14a) by sucking the refrigerant from the refrigerant suction port (14b) by the high-speed refrigerant flow injected from the nozzle part (14a). An ejector (14) that mixes and discharges the refrigerant sucked from the suction port (14b) , a first evaporator (15) that is disposed on the outflow side of the ejector (14) and has a predetermined pressure loss, and an ejector The second evaporator (18) having a predetermined pressure loss is disposed on the suction side of (14) , and the first evaporator (15), the second evaporator (18), and the ejector (14) are integrated. In the evaporator unit (20) assembled to the refrigerant, the refrigerant branch passage is branched from the inlet side of the ejector, the downstream side of the refrigerant branch passage is connected to the refrigerant suction port of the ejector, and the second evaporator is provided in the refrigerant branch passage. Placed Thus, when the system is at the maximum load condition, the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is set to be smaller than the pressure increase amount (PE) by the ejector (14), and the system is at the maximum load condition. Sometimes, the pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is set to be smaller than the pressure increase (PE) by the ejector (14), and the second evaporator is in the maximum load condition. The first evaporator (15) and the second evaporator (18) are set so that the refrigerant pressure loss (ΔP2) in (18) is less than the refrigerant pressure loss (ΔP1) in the first evaporator (15). In addition, a plurality of ejectors (14) are arranged in the header tank portions (15b, 18b) of the first evaporator (15) and the second evaporator (18). The

According to the present invention , it is possible to increase the refrigerant flow path cross-sectional area in the header tank portion by using a plurality of ejectors having a small diameter that can achieve the same effect, rather than arranging one ejector in the header tank portion. It becomes. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

Further, the invention described in claim 7 is characterized in that, in the evaporator unit described in claim 6 , a plurality of ejectors (14) are arranged in one header tank portion (18b).

According to the seventh aspect of the present invention, the header tank can be obtained by using a plurality of ejectors having a small diameter that can achieve the same effect in the single header tank portion (18b) rather than disposing one ejector. It becomes possible to enlarge the refrigerant | coolant flow path cross-sectional area in a part (18b). Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  In addition, the code | symbol in the parenthesis as described in a claim and said each means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of an ejector refrigeration cycle and an evaporator unit used therefor according to the present invention will be described. The evaporator unit can also be called a heat exchanger unit, an ejector-type refrigeration cycle unit, an ejector-type refrigeration cycle evaporator unit, or an ejector-equipped evaporator unit.

  Since the evaporator unit constitutes a refrigeration cycle including an ejector, the evaporator unit is connected to a radiator, which is another component of the refrigeration cycle, and a compressor via a pipe. In one embodiment, the evaporator unit is used as an indoor unit for cooling air. Moreover, an evaporator unit can also be used as an outdoor unit in another form.

  FIGS. 1-10 represents 1st Embodiment of this invention, FIG. 1 is a schematic diagram of the example which applied the ejector type refrigeration cycle 10 of embodiment to the refrigeration cycle apparatus for vehicles. In the ejector refrigeration cycle 10 of the present embodiment, a compressor 11 that sucks and compresses refrigerant is rotationally driven by a vehicle travel engine (not shown) via an electromagnetic clutch 11a, a V belt (not shown), and the like.

  The compressor 11 may be a variable capacity type compressor that can adjust the refrigerant discharge capacity by changing the compression capacity, or a fixed capacity type that adjusts the refrigerant discharge capacity by changing the operating rate of the compressor operation by switching the electromagnetic clutch 11a. Any of the compressors may be used. Further, if an electric compressor is used as the compressor 11, the refrigerant discharge capacity can be adjusted by adjusting the rotation speed of the electric motor. In FIG. 1, the electromagnetic clutch 11a is controlled to be intermittently controlled by an output from a control device (not shown).

  A radiator 12 is disposed on the refrigerant discharge side of the compressor 11. The radiator 12 cools the high-pressure refrigerant by exchanging heat between the high-pressure refrigerant discharged from the compressor 11 and the outside air (air outside the passenger compartment) blown by a cooling fan (not shown). Here, as the refrigerant of the ejector-type refrigeration cycle 10, a vapor compression type subcritical pressure cycle is configured using a refrigerant whose high pressure does not exceed the critical pressure, such as a refrigerant of chlorofluorocarbon or HC, in the present embodiment. is doing. For this reason, the radiator 12 acts as a condenser that condenses the refrigerant.

  A liquid receiver 12 a is provided on the outlet side of the radiator 12. As is well known, the liquid receiver 12a has a vertically long tank shape, and constitutes a gas-liquid separator that separates the gas-liquid refrigerant and accumulates excess refrigerant in the cycle as liquid refrigerant. At the outlet of the liquid receiver 12a, liquid refrigerant is led out from the lower side inside the tank shape. In addition, the liquid receiver 12a is provided integrally with the heat radiator 12 in this example.

  Further, as the radiator 12, a heat exchanger for condensation located on the upstream side of the refrigerant flow, a liquid receiver 12a for introducing the refrigerant from the heat exchanger for condensation and separating the gas and liquid of the refrigerant, and the liquid receiver A known configuration having a supercooling heat exchange section for supercooling the saturated liquid refrigerant from the vessel 12a may be employed. A temperature type expansion valve 13 is disposed on the outlet side of the liquid receiver 12a. This temperature type expansion valve 13 is a pressure reducing means for reducing the pressure of the liquid refrigerant from the liquid receiver 12 a and has a temperature sensing part 13 a disposed in the suction side passage of the compressor 11.

  As is well known, the temperature type expansion valve 13 detects the degree of superheat of the compressor suction side refrigerant based on the temperature and pressure of the suction side refrigerant (evaporator outlet side refrigerant described later) of the compressor 11 and sucks the compressor. The valve opening (refrigerant flow rate) is adjusted so that the degree of superheat of the side refrigerant becomes a predetermined value set in advance. An ejector 14 is disposed on the outlet side of the temperature type expansion valve 13. The ejector 14 is a pressure reducing means for reducing the pressure of the refrigerant, and is also a fluid circulating refrigerant circulating means (momentum transport type pump) that circulates the refrigerant by a suction action (winding action) of the refrigerant flow ejected at a high speed.

  The ejector 14 includes a nozzle part (an inlet throttle mechanism) 14a that further expands the refrigerant under reduced pressure by reducing the passage area of the refrigerant (intermediate pressure refrigerant) after passing through the expansion valve 13, and the refrigerant in the nozzle part 14a. A refrigerant suction port 14b is provided which is disposed in the same space as the jet port and sucks a gas-phase refrigerant from a second evaporator (leeward side heat exchange unit) 18 which will be described later.

  Furthermore, a mixing portion 14c that mixes the high-speed refrigerant flow from the nozzle portion 14a and the suction refrigerant of the refrigerant suction port 14b is provided in the refrigerant flow downstream portion of the nozzle portion 14a and the refrigerant suction port 14b. And the diffuser part 14d which comprises a pressure | voltage rise part is arrange | positioned in the refrigerant | coolant flow downstream of the mixing part 14c. The diffuser portion 14d is formed in a shape that gradually increases the refrigerant passage area, and serves to increase the refrigerant pressure by decelerating the refrigerant flow, that is, to convert the velocity energy of the refrigerant into pressure energy. .

  A first evaporator (windward heat exchange unit) 15 is connected to the outlet side of the diffuser portion 14 d of the ejector 14, and the outlet side of the first evaporator 15 is connected to the suction side of the compressor 11. On the other hand, a refrigerant branch passage 16 is branched from the inlet side of the ejector 14 (an intermediate portion between the outlet side of the temperature type expansion valve 13 and the inlet side of the ejector 14), and the downstream side of the refrigerant branch passage 16 is connected to the ejector 14. It is connected to the refrigerant suction port 14b. z indicates a branch point of the refrigerant branch passage 16.

  A throttle mechanism (an inlet throttle mechanism in the present invention) 17 is disposed in the refrigerant branch passage 16, and a second evaporator 18 is disposed downstream of the throttle mechanism 17 in the refrigerant flow. The throttle mechanism 17 is a pressure reducing means that adjusts the flow rate of the refrigerant to the second evaporator 18. Specifically, in the present embodiment, the throttle mechanism 17 is configured by a fixed throttle such as a capillary tube or an orifice.

  Further, in the present embodiment, the two evaporators 15 and 18 are assembled into an integral structure by the configuration described later. The two evaporators 15 and 18 are housed in an air conditioning case (not shown), and air (cooled air) is blown into an air passage formed in the air conditioning case by a common electric blower 19 as indicated by an arrow A. The blown air is cooled by the two evaporators 15 and 18.

  The electric blower 19 is an electric fan driven by a motor 19a, and the motor 19a is rotationally driven by a control voltage output from a control device (not shown). The cold air cooled by the two evaporators 15 and 18 is sent to a common cooling target space (not shown), and thereby the common cooling target space is cooled by the two evaporators 15 and 18. . When the ejector refrigeration cycle 10 of the present embodiment is applied to a vehicle air conditioning refrigeration cycle apparatus, the vehicle interior space becomes the cooling target space.

  Further, when the ejector refrigeration cycle 10 of the present embodiment is applied to a refrigeration cycle apparatus for a refrigeration vehicle, the space inside the refrigeration refrigerator of the refrigeration vehicle is a space to be cooled. Here, of the two evaporators 15 and 18, the first evaporator 15 connected to the main flow path on the downstream side of the ejector 14 is arranged on the upstream side (windward side) of the air flow A, and the refrigerant suction port of the ejector 14 is arranged. The second evaporator 18 connected to 14b is arranged on the downstream side (leeward side) of the air flow A.

  Next, the operation in the above configuration will be described based on the ph diagram of FIG. FIG. 2 is a ph diagram when the pressure increase amount PE of the ejector 14 is large in the vehicle ejector refrigeration cycle 10 of FIG. Here, points aa to hh in FIG. 2 correspond to points aa to hh in FIG. 1.

  Similarly, FIG. 3 is a ph diagram when the pressure increase amount PE of the ejector 14 is small, and FIG. 4 is a ph diagram when the pressure loss coefficient of the evaporator is large. 2 to 4, the broken line written in the drawings is an expansion valve cycle for comparison, and the first evaporator outlet evaporation point (compressor intake state point) is shown for easy comparison. ff is written together.

  When the compressor 11 is started, the gas-phase refrigerant is sucked into the compressor 11 from the first evaporator 15, and the compressed refrigerant having the flow rate Gn is discharged to the radiator 12 (ff → aa). In the radiator 12, the high-temperature refrigerant is cooled and condensed by the outside air (aa → bb). The high-pressure liquid refrigerant having a flow rate Gn flowing out of the radiator 12 is divided into a refrigerant flow having a flow rate Ge toward the branching refrigerant passage 16 and a refrigerant flow having a flow rate Gn-Ge toward the ejector 14 at the branch point z.

  The refrigerant flow having the flow rate Gn-Ge flowing into the ejector 14 is isentropically depressurized by the nozzle portion 14a and expanded (bb → cc). Therefore, the pressure energy of the refrigerant is converted into velocity energy at the nozzle portion 14a, and the refrigerant is ejected at a high velocity from the outlet of the nozzle portion 14a. At this time, the gas-phase refrigerant having a flow rate Ge is sucked from the second evaporator 18 into the refrigerant suction port 14b by the pressure drop of the refrigerant flow ejected at a high speed.

  The refrigerant ejected from the nozzle portion 14a and the refrigerant sucked into the refrigerant suction port 14b are mixed in the mixing portion 14c on the downstream side of the nozzle portion 14a (cc → dd, hh → dd) and flow into the diffuser portion 14d. In the diffuser portion 14d, the refrigerant pressure (ris → ee) increases because the velocity (expansion) energy of the refrigerant is converted into pressure energy due to the expansion of the passage area.

  Then, the refrigerant having the flow rate Gn flowing out from the diffuser portion 14 d of the ejector 14 flows into the first evaporator 15. In the first evaporator 15, the low-temperature low-pressure refrigerant absorbs heat from the blown air in the direction of arrow A at the heat exchange core portion 15a and evaporates (ee → ff). The vapor phase refrigerant after evaporation is sucked into the compressor 11 and compressed again.

  On the other hand, the refrigerant flow of the flow rate Ge flowing into the branch refrigerant passage 16 is decompressed by the throttle mechanism 17 to become a low-pressure refrigerant (bb → gg), and this low-pressure refrigerant flows into the second evaporator 18. In the second evaporator 18, the refrigerant absorbs heat from the blown air in the direction of arrow A and evaporates (gg → hh). The vapor phase refrigerant having the flow rate Ge after the evaporation is sucked into the ejector 14 from the refrigerant suction port 14b.

  As described above, the refrigerant having the flow rate Gn can be supplied to the first evaporator 15 and the refrigerant on the branch passage 16 side can be supplied to the second evaporator 18 as the refrigerant having the flow rate Ge through the throttle mechanism 17. The two evaporators 15 and 18 can simultaneously exert a cooling action. Therefore, the cooling target space can be cooled (cooled) by blowing the cool air cooled by both the first and second evaporators 15 and 18 to the cooling target space.

  Incidentally, the pressure increase amount PE by the ejector 14 shown in FIG. 2 includes the refrigerant pressure Po2 at the inlet of the refrigerant suction port 14 (flowing out of the second evaporator 18) of the ejector 14 and the outlet of the diffuser portion 14d (first evaporator 15). This is the pressure difference (Pi1-Po2) with the refrigerant pressure Pi1 and is measured in the actual machine within a maximum range of 30 mm from both inlets and outlets.

  The refrigerant pressure loss ΔP1 in the first evaporator 15 is a pressure difference (Pi1−Po1) between the refrigerant pressure Pi1 at the refrigerant inlet of the first evaporator 15 and the refrigerant pressure Po1 at the refrigerant outlet. Is also measured within a maximum range of 30 mm from both inlets and outlets. Similarly, the pressure loss ΔP2 of the refrigerant in the second evaporator 18 is a pressure difference (Pi2-Po2) between the refrigerant pressure Pi2 at the refrigerant inlet of the second evaporator 18 and the refrigerant pressure Po2 at the refrigerant outlet. Is also measured within a maximum range of 30 mm from both inlets and outlets.

  Thus, the refrigerant evaporation pressure Po2 in the second evaporator 18 is lower than the refrigerant evaporation pressure Po1 in the first evaporator 15. Accordingly, the refrigerant evaporation temperature of the second evaporator 18 is lower than the refrigerant evaporation temperature of the first evaporator 15. And since the 1st evaporator 15 with a high refrigerant | coolant evaporation temperature is arrange | positioned in the upstream with respect to the flow direction A of blowing air, and the 2nd evaporator 18 with a low refrigerant | coolant evaporation temperature is arrange | positioned in the downstream, the 1st It is possible to secure both the temperature difference between the refrigerant evaporation temperature and the blown air in the evaporator 15 and the temperature difference between the refrigerant evaporation temperature and the blown air in the second evaporator 18.

  For this reason, both the cooling performance of the 1st, 2nd evaporators 15 and 18 can be exhibited effectively. Therefore, the cooling performance for the common space to be cooled can be effectively improved by the combination of the first and second evaporators 15 and 18. Further, the suction pressure of the compressor 11 can be increased by the pressure increasing action in the diffuser portion 14d represented by PE, and the driving power of the compressor 11 can be reduced.

  Further, as a feature of the present embodiment, the refrigerant pressure loss ΔP1 in the first evaporator 15 and the refrigerant pressure loss ΔP2 in the second evaporator 18 are smaller than the pressure increase amount PE by the ejector 14 when the system is under a maximum load condition. It is set to be. Further, the first and second evaporators 15 and 18 are set so that the pressure loss ΔP2 in the second evaporator 18 is smaller than the pressure loss ΔP1 in the first evaporator 15 when the system is under the maximum load condition.

  In addition, as the maximum load condition of the system mentioned here, it is assumed that the outside air temperature is 42 ° C. and the refrigerant circulation amount in the system is maximized. And the refrigerant | coolant flow path cross-sectional area of the 1st, 2nd evaporators 15 and 18 is set so that it may become the above-mentioned pressure relationship also at the time of conditions in this way. More specifically, the refrigerant channel cross-sectional areas of the evaporators 15 and 18 are set so that these pressure losses ΔP1 and ΔP2 are 100 kPa or less.

If this condition is replaced with the refrigerant minimum channel cross section, the hydraulic diameter is set to 10 mm or more. The refrigerant minimum channel cross section is the minimum channel cross section including the inlet and outlet of the refrigerant flow. In this embodiment, the minimum refrigerant channel cross section is 78.5 mm ² , which is expressed as “hydraulic diameter d = 4 × cross-sectional area / wetting edge length”. It becomes 10 mm from the relationship of “sa”. In addition, when there are a plurality of flow paths in parallel, the total is the cross section of each flow path.

  Further, the inlet throttle mechanisms of the first and second evaporators 15, 18, specifically nozzles, so that the refrigerant pressure Po 2 at the outlet of the second evaporator 18 becomes equal to or lower than the refrigerant pressure Po 1 at the outlet of the first evaporator 15. The part 14a and the diaphragm mechanism 17 are set. In addition, although the setting in each evaporator is considered with the refrigerant | coolant flow path cross-sectional area in the above, you may consider with a refrigerant | coolant mass flow velocity. The refrigerant mass flow rate is a value obtained by dividing the refrigerant mass flow rate by the refrigerant flow path cross-sectional area in each part of the refrigerant flow such as in a header tank or a tube, which will be described later.

  As means for adjusting the refrigerant mass flow rate, The refrigerant flow path length is varied by devising the number of turns. 2. Corresponding to the degree of dryness in the evaporator, the number of tubes on the upstream side and the downstream side is varied in a heat exchange core part described later. 3. The refrigerant channel cross-sectional area in the header tank part is varied. 4). As described above, the refrigerant flow rate is varied by the inlet throttle mechanism of each of the first and second evaporators 15 and 18. There are means such as.

  By adjusting to the above pressure conditions including these means, the average evaporation temperature in the first and second evaporators 15 and 18 can be made lower than that of the conventional expansion valve cycle, and the The cooling performance can be reliably improved by increasing the temperature difference from the fluid to be cooled. A specific method for varying the refrigerant flow path cross-sectional area in the header tank is also a feature of the present embodiment, which will be described later.

  By the way, in this embodiment, the ejector 14, the first and second evaporators 15 and 18, and the throttle mechanism 17 are assembled as one integrated unit (evaporator unit) 20. Next, a specific example of the integrated unit 20 will be described with reference to FIGS. 5 is a perspective view showing an outline of the overall configuration of the integrated unit 20, FIG. 6 is a lateral (longitudinal) cross-sectional view of the upper tank portions 15b and 18b of the first and second evaporators 15 and 18, and FIG. 4 is a longitudinal sectional view of an upper tank portion 18b of the second evaporator 18. FIG.

  Next, a specific example of the integrated structure of the two evaporators 15 and 18 will be described with reference to FIG. In the example of FIG. 5, the two evaporators 15 and 18 are completely integrated as one evaporator structure. Therefore, the first evaporator 15 constitutes an upstream region of the air flow A in one evaporator structure, and the second evaporator 18 constitutes a downstream region of the air flow A in one evaporator structure. It has become.

  In addition, each of the up, down, left and right arrows in FIG. 5 indicates the side where the ejector 14 of the second evaporator 18 is disposed as viewed from the downstream side in the flow direction of the blown air indicated by the arrow A, and the ejector 14 is disposed. The not-shown side is shown as the downward direction, the upstream side of the nozzle portion 14a of the ejector 14 is shown as the left direction, and the downstream side of the diffuser portion 14d of the ejector 14 is shown as the right direction. In the following description, the upper, lower, left, and right directions are similar directions.

  The basic configurations of the first and second evaporators 15 and 18 are the same, and the heat exchange core portions 15a and 18a and header tank portions (hereinafter referred to as tanks) located on both upper and lower sides of the heat exchange core portions 15a and 18a, respectively. 15b, 15c, 18b, 18c. Here, each of the heat exchange core portions 15a and 18a includes a plurality of tubes 21 extending in the vertical direction, and a passage through which the heat exchange medium, which is cooled in the present embodiment, passes between the plurality of tubes 21. Is formed. Further, fins 22 are disposed between the plurality of tubes 21 and the tubes 21 and the fins 22 are joined by brazing.

  The heat exchange core portions 15 a and 18 a have a laminated structure of tubes 21 and fins 22. The tubes 21 and the fins 22 are alternately stacked in the left-right direction of the heat exchange core portions 15a and 18a. As another embodiment, a configuration without the fins 22 may be used. Further, in FIG. 5, only a part of the laminated structure of the tube 21 and the fin 22 is illustrated, but the laminated structure of the tube 21 and the fin 22 is configured over the entire heat exchange core portions 15a and 18a. The air blown by the electric blower 19 passes through the gap portion of the laminated structure.

  The tube 21 constitutes a refrigerant passage, and is formed of a flat tube whose cross-sectional shape is flat along the air flow direction A. The fin 22 is a corrugated fin obtained by bending a thin plate material into a wave shape, and is joined to the flat outer surface side of the tube 21 to expand the air-side heat transfer area. The tube 21 of the heat exchange core portion 15a and the tube 21 of the heat exchange core portion 18a constitute independent refrigerant passages. The tank portions 15b and 15c on both the upper and lower sides of the first evaporator 15 and the second evaporator 18 The tank portions 18b and 18c on both the upper and lower sides constitute independent refrigerant passage spaces.

  The tank portions 15b and 15c on both the upper and lower sides of the first evaporator 15 have tube fitting hole portions (not shown) into which the upper and lower ends of the tube 21 of the heat exchange core portion 15a are inserted and joined. Both end portions communicate with the internal spaces of the tank portions 15b and 15c.

  Similarly, the tank portions 18b and 18c on both the upper and lower sides of the second evaporator 18 have tube fitting holes (not shown) into which the upper and lower ends of the tube 21 of the heat exchange core portion 18a are inserted and joined. The upper and lower end portions of 21 communicate with the internal spaces of the tank portions 18b and 18c. In addition, since the tip shape of the tube 21 inserted in each tank part is also one of the features of this embodiment, the details will be described later.

  As a result, the tank portions 15b, 15c, 18b, and 18c on the upper and lower sides distribute the refrigerant flow to the plurality of tubes 21 of the corresponding heat exchange core portions 15a and 18a, respectively, or collect the refrigerant flows from the plurality of tubes 21. Or play a role. Since the two upper tank portions 15b, 18b and the two lower tank portions 15c, 18c are adjacent to each other, the two upper tank portions 15b, 18b and the two lower tank portions 15c, 18c are integrally formed. can do.

  Of course, the two upper tank portions 15b and 18b and the two lower tank portions 15c and 18c may be configured as independent members. In addition, as a concrete material of the evaporator components such as the tube 21, the fin 22, the tank portions 15 b, 15 c, 18 b, and 18 c, aluminum which is a metal excellent in thermal conductivity and brazing property is suitable. By forming each part with an aluminum material, the entire configuration of the first and second evaporators 15 and 18 is joined by integrated brazing after assembly.

  In the present embodiment, the first and second evaporators 15, the first and second evaporators 15 by brazing the first and second connection blocks 23 and 24 of the refrigerant passage shown in FIG. Assembling with 18 is integrated. On the other hand, since the ejector 14 forms a high-precision minute passage in the nozzle portion 14a, when the ejector 14 is brazed, a high temperature during brazing (a brazing temperature of aluminum: around 600 ° C.). The nozzle part 14a is thermally deformed, resulting in a problem that the passage shape and dimensions of the nozzle part 14a cannot be maintained as designed.

  Therefore, the ejector 14 is assembled to the evaporator side after the first and second evaporators 15 and 18, the first and second connection blocks 23 and 24 and the throttle mechanism 17 are integrally brazed. is there. More specifically, the assembly structure of the ejector 14, the throttle mechanism 17, and the first and second connection blocks 23 and 24 will be described. The throttle mechanism 17 and the first and second connection blocks 23 and 24 include Similarly, it is formed of an aluminum material.

  As shown in FIG. 6, the first connection block 23 is a member that is brazed and fixed to a side surface portion at one end in the longitudinal direction of the upper tank portions 15b and 18b of the first and second evaporators 15 and 18. The refrigerant inlet 25 and the refrigerant outlet 26 of the integrated unit 20 shown in FIG. In the middle of the thickness direction of the first connection block 23, the refrigerant inlet 25 forms a main passage 25 a that forms a first passage toward the inlet side of the ejector 14 and a second passage that extends toward the inlet side of the throttle mechanism 17. Branches to the branch passage 16.

  This branch passage 16 corresponds to an inlet portion of the branch passage 16 in FIG. Therefore, the branch point z in FIG. 1 is configured inside the first connection block 23. On the other hand, the refrigerant outlet 26 is constituted by one simple passage hole (circular hole or the like) penetrating in the thickness direction of the first connection block 23. The branch passage 16 of the first connection block 23 is sealed and joined to one end portion (the left end portion in FIGS. 5 and 6) of the throttle mechanism 17 by brazing.

  The second connection block 24 is a member that is disposed at a substantially central portion in the longitudinal direction of the internal space in the upper tank portion 18b of the second evaporator 18 and is brazed to the inner wall surface of the upper tank portion 18b. The second connection block 24 serves to partition the internal space of the upper tank portion 18b into two spaces in the tank longitudinal direction, that is, a left space 27 and a right space 28. The other end side (right end side) of the throttle mechanism 17 passes through the support hole 24a of the second connection block 24 and opens into the right space 28 of the upper tank portion 18b, as shown in FIG.

  Since the space between the outer peripheral surface of the aperture mechanism 17 and the support hole 24a is sealed by brazing, the space between the left and right spaces 27 and 28 remains blocked. Of the ejector 14, the nozzle portion 14a is made of a material such as stainless steel or brass, and portions other than the nozzle portion 14a (housing portions forming the refrigerant suction port 14b, mixing portion 14c, diffuser portion 14d, etc.) are made of copper, aluminum, or the like. It is composed of a metal material. However, you may comprise with nonmetallic materials, such as resin.

  The ejector 14 passes through the hole shapes of the refrigerant inlet 25 and the main passage 25a of the first connection block 23 after the assembly process (the brazing process) for integrally brazing the first and second evaporators 15 and 18 and the like. Are inserted into the upper tank portion 18b. Here, the front end portion of the ejector 14 in the longitudinal direction is a portion corresponding to the outlet portion of the diffuser portion 14d in FIG. The tip of the ejector is inserted into the circular recess 24b of the second connection block 24 and is sealed with an O-ring 29a.

  The ejector tip communicates with the communication hole 24 c of the second connection block 24. In the upper tank portion 15b of the first evaporator 15, a partition plate 30 is disposed at a substantially central portion in the longitudinal direction of the internal space, and the internal space of the upper tank portion 15b is divided into two spaces in the longitudinal direction by the partition plate 30. That is, the left space 31 and the right space 32 are partitioned. The communication hole portion 24c of the second connection block 24 communicates with the right space 32 of the upper tank portion 15b of the first evaporator 15 through the through hole 33a of the intermediate wall surface 33 of both the upper tank portions 15b and 18b. .

  The left end in the longitudinal direction of the ejector 14 (left end in FIG. 6) is a portion corresponding to the inlet of the nozzle portion 14a in FIG. 1, and this left end is the main connection block 23 using an O-ring 29b. It is fitted and fixed to the inner wall surface of the passage 25a. The ejector 14 may be fixed in the longitudinal direction using, for example, screw fixing means (not shown). The O-ring 29a is held in a groove portion (not shown) of the second connection block 24, and the O-ring 29b is held in a groove portion tube 21 (not shown) of the first connection block 23.

  In the first connection block 23, the refrigerant outlet 26 communicates with the left space 31 of the upper tank portion 15 b, the main passage 25 a communicates with the left space 27 of the upper tank portion 18 b, and the branch passage 16 extends from the throttle mechanism 17. It is brazed to the side walls of the upper tank portions 15b, 18b in a state of communicating with the one end portion. Further, the refrigerant suction port 14 b of the ejector 14 communicates with the left space 27 of the upper tank portion 18 b of the second evaporator 18.

  In the present embodiment, the inside of the upper tank portion 18b of the second evaporator 18 is divided into left and right spaces 27, 28 by the second connection block 24, and the left space 27 serves as a collective tank that collects refrigerant from the plurality of tubes 21. The right space 28 serves as a distribution tank that distributes the refrigerant to the plurality of tubes 21. The ejector 14 has an elongated cylindrical shape extending in the axial direction of the nozzle portion 14a. The longitudinal direction of the elongated cylindrical shape is aligned with the longitudinal direction of the upper tank portion 18b, and the ejector 14 is parallel to the upper tank portion 18b. Is installed.

  With this configuration, the ejector 14 and the evaporator 18 can be arranged in a compact manner, and as a result, the physique of the entire unit can be gathered in a compact manner. Moreover, the ejector 14 is disposed in the left space 27 forming the collective tank, and the refrigerant suction port 14b is directly opened in the left space 27 forming the collective tank. This configuration makes it possible to reduce refrigerant piping.

  This configuration provides an advantage that the collection of refrigerant from the plurality of tubes 21 and the supply of refrigerant (refrigerant suction) to the ejector 14 can be realized with one tank. In the present embodiment, the first evaporator 15 is provided adjacent to the second evaporator 18, and the downstream end of the ejector 14 is connected to the distribution tank (the upper tank portion 15 b of the first evaporator 15). It is installed adjacent to the right space 32).

  In this configuration, even if the ejector 14 is disposed in the tank portion on the second evaporator 18 side, the refrigerant flowing out from the ejector 14 is firstly passed through a very short simple refrigerant passage (holes 24c and 33a). This provides the advantage that it can be supplied to the one evaporator 15 side. The refrigerant flow path of the entire integrated unit 20 in the above configuration will be specifically described with reference to FIGS.

  The refrigerant inlet 25 of the first connection block 23 is branched into a main passage 25 a and a branch passage 16. First, the refrigerant in the main passage 25a passes through the ejector 14 (nozzle part 14a → mixing part 14c → diffuser part 14d) and is decompressed, and the decompressed low-pressure refrigerant is communicated with the communication hole 24c, the intermediate wall surface of the second connection block 24. It flows into the right space 32 of the upper tank portion 15b of the first evaporator 15 through the through hole 33a of 33 as shown by the arrow a.

  The refrigerant in the right space 32 descends the plurality of tubes 21 on the right side of the heat exchange core portion 15a as indicated by an arrow b and flows into the right side in the lower tank portion 15c. Since no partition plate is provided in the lower tank portion 15c, the refrigerant from the right side of the lower tank portion 15c moves to the left side as indicated by an arrow c.

  The refrigerant on the left side of the lower tank portion 15c moves up the plurality of tubes 21 on the left side of the heat exchange core portion 15a as shown by the arrow d and flows into the left space 31 of the upper tank portion 15b. The refrigerant flows to the refrigerant outlet 26 of the first connection block 23 as indicated by an arrow e. On the other hand, the refrigerant in the branch passage 16 of the first connection block 23 first passes through the throttle mechanism 17 and is depressurized. The low-pressure refrigerant after this depressurization is the upper tank portion of the second evaporator 18 as indicated by the arrow f. It flows into the right space 28 of 18b.

  The refrigerant in the right space 28 descends the plurality of tubes 21 on the right side of the heat exchange core portion 18a as indicated by an arrow g and flows into the right side portion in the lower tank portion 18c. Since no partition plate is provided in the lower tank portion 18c, the refrigerant moves from the right side portion of the lower tank portion 18c to the left side as indicated by an arrow h.

  The refrigerant on the left side of the lower tank portion 18c moves up the plurality of tubes 21 on the left side of the heat exchange core portion 18a as indicated by arrow i and flows into the left space 27 of the upper tank portion 18b. Since the refrigerant suction port 14b of the ejector 14 is opened in the left space 27, the refrigerant in the left space 27 is sucked into the ejector 14 from the refrigerant suction port 14b. Since the integrated unit 20 has the above-described refrigerant flow path configuration, the integrated unit 20 as a whole need only have one refrigerant inlet 25 in the first connection block 23, and the refrigerant outlet 26 also has the first connection. Only one block 23 needs to be provided.

  Next, an outline of the operation of this embodiment will be described. When the compressor 11 is driven by the vehicle running engine, the high-temperature and high-pressure refrigerant compressed and discharged by the compressor 11 flows into the radiator 12. In the radiator 12, the high-temperature refrigerant is cooled and condensed by the outside air. The high-pressure refrigerant that has flowed out of the radiator 12 flows into the liquid receiver 12a, where the gas-liquid refrigerant is separated in the liquid receiver 12a, and the liquid refrigerant is led out from the liquid receiver 12a and passes through the expansion valve 13. .

  In the expansion valve 13, the valve opening degree (refrigerant flow rate) is adjusted so that the degree of superheat of the outlet refrigerant (compressor suction refrigerant) of the first evaporator 15 becomes a predetermined value, and the high-pressure refrigerant is decompressed. The refrigerant (intermediate pressure refrigerant) after passing through the expansion valve 13 flows into the refrigerant inlet 25 provided in the first connection block 23 of the integrated unit 20.

  Here, the refrigerant flow is divided into a refrigerant flow from the main passage 25 a of the first connection block 23 toward the ejector 14 and a refrigerant flow from the refrigerant branch passage 16 of the first connection block 23 toward the throttle mechanism 17. And the refrigerant | coolant flow which flowed into the ejector 14 is decompressed and expanded by the nozzle part 14a. Therefore, the pressure energy of the refrigerant is converted into velocity energy at the nozzle portion 14a, and the refrigerant is ejected at a high velocity from the outlet of the nozzle portion 14a.

  Due to the refrigerant pressure drop at this time, the refrigerant (gas phase refrigerant) after passing through the second evaporator 18 in the branch refrigerant passage 16 is sucked from the refrigerant suction port 14b. The refrigerant ejected from the nozzle portion 14a and the refrigerant sucked into the refrigerant suction port 14b are mixed in the mixing portion 14c on the downstream side of the nozzle portion 14a and flow into the diffuser portion 14d. In the diffuser portion 14d, the passage area is enlarged, so that the speed (expansion) energy of the refrigerant is converted into pressure energy, so that the pressure of the refrigerant increases.

  And the refrigerant | coolant which flowed out from the diffuser part 14d of the ejector 14 flows in the refrigerant | coolant flow path of the arrow ae of FIG. During this time, in the heat exchange core portion 15a of the first evaporator 15, the low-temperature low-pressure refrigerant absorbs heat from the blown air in the direction of arrow A and evaporates. The vapor phase refrigerant after evaporation is sucked into the compressor 11 from the refrigerant outlet 26 and compressed again.

  On the other hand, the refrigerant flow that has flowed into the refrigerant branch passage 16 is decompressed by the throttle mechanism 17 to become low-pressure refrigerant, and this low-pressure refrigerant flows through the refrigerant flow paths indicated by arrows f to i in FIG. During this time, in the heat exchange core portion 18 a of the second evaporator 18, the low-temperature low-pressure refrigerant absorbs heat from the blown air that has passed through the first evaporator 15 and evaporates. The vapor phase refrigerant after evaporation is sucked into the ejector 14 from the refrigerant suction port 14b.

  As described above, according to the present embodiment, the refrigerant on the downstream side of the diffuser portion 14d of the ejector 14 is supplied to the first evaporator 15, and the refrigerant on the refrigerant branch passage 16 side also enters the second evaporator 18 through the throttle mechanism 17a. Since it can be supplied, the first and second evaporators 15 and 18 can simultaneously exhibit a cooling action. Therefore, the cooling target space can be cooled (cooled) by blowing the cool air cooled by both the first and second evaporators 15 and 18 to the cooling target space.

  At this time, the refrigerant evaporation pressure of the first evaporator 15 is the pressure after being increased by the diffuser portion 14d, while the outlet side of the second evaporator 18 is connected to the refrigerant suction port 14b of the ejector 14. The lowest pressure immediately after the pressure reduction at the nozzle portion 14 a can be applied to the second evaporator 18.

  Thereby, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the second evaporator 18 can be made lower than the refrigerant evaporation pressure (refrigerant evaporation temperature) of the first evaporator 15. And since the 1st evaporator 15 with a high refrigerant | coolant evaporation temperature is arrange | positioned in the upstream with respect to the flow direction A of blowing air, and the 2nd evaporator 18 with a low refrigerant | coolant evaporation temperature is arrange | positioned in the downstream, the 1st It is possible to secure both the temperature difference between the refrigerant evaporation temperature and the blown air in the evaporator 15 and the temperature difference between the refrigerant evaporation temperature and the blown air in the second evaporator 18.

  For this reason, both the cooling performance of the 1st, 2nd evaporators 15 and 18 can be exhibited effectively. Therefore, the cooling performance for the common space to be cooled can be effectively improved by the combination of the first and second evaporators 15 and 18. Further, the suction pressure of the compressor 11 can be increased by the pressure increasing action in the diffuser portion 14d, and the driving power of the compressor 11 can be reduced.

  Further, the refrigerant flow rate on the second evaporator 18 side can be adjusted independently by the throttle mechanism 17 without depending on the function of the ejector 14, and the refrigerant flow rate to the first evaporator 15 can be adjusted by the throttle characteristic of the ejector 14. . For this reason, the refrigerant | coolant flow volume to the 1st, 2nd evaporators 15 and 18 can be easily adjusted corresponding to each heat load.

  Further, under the condition where the cycle heat load is small, the high / low pressure difference of the cycle becomes small and the input of the ejector 14 becomes small. In the present embodiment, the refrigerant that has passed through the expansion valve 13 is branched at the upstream portion of the ejector 14, and this branched refrigerant is sucked into the refrigerant suction port 14 b through the refrigerant branch passage 16, so that the refrigerant branch passage 16 is connected to the ejector 14. Parallel connection.

  For this reason, the refrigerant can be supplied to the refrigerant branch passage 16 by utilizing not only the refrigerant suction capability of the ejector 14 but also the refrigerant suction / discharge capability of the compressor 11. Thereby, even if the phenomenon that the input of the ejector 14 decreases and the refrigerant suction capacity of the ejector 14 decreases occurs, the degree of decrease in the refrigerant flow rate on the second evaporator 18 side can be reduced. Therefore, it is easy to ensure the cooling performance of the second evaporator 18 even under low heat load conditions.

  Next, in the heat exchanger unit having the above-described configuration, a method for changing the refrigerant flow path cross-sectional area in the tank portion, which is a feature of the present embodiment, will be described with reference to FIGS. In the present embodiment, the distal end shape of the tube 21 inserted into the tank portions 15b, 15c, 18b, 18c has a shape in which the central portion is recessed with respect to both end portions in the width direction of the tube 21, FIG. 8A shows an example in which the distal end shape of the tube 21 is aligned with the outer shape of the ejector 14 in the tank portion 18b, and FIG.

  FIG. 9 is an example in which the tip shape of the tube 21 is along the inner surface shape of the tank portions 15b, 15c, 18b, and 18c on the tube insertion side in both (a) and (b). 10 (a) to 10 (c) are other examples of the tip shape of the tube 21, and as shown, the tip shape of the tube 21 is concave, V-shaped, U-shaped, or the like. May be. Any of these methods can increase the refrigerant flow path cross-sectional area in the tank portions 15b, 15c, 18b, and 18c, and can reduce the refrigerant pressure loss of the first and second evaporators 15 and 18, thereby improving the cooling performance. Can be improved.

  Next, features and effects of this embodiment will be described. First, in an ejector-type refrigeration cycle in which evaporators 15 and 18 having a predetermined pressure loss are arranged on at least one of the suction side and the outflow side of the ejector 14, the pressure of the refrigerant in the evaporators 15 and 18 when the system is under a maximum load condition. The losses ΔP1 and ΔP2 are set to be smaller than the boosted amount PE by the ejector 14.

  According to this, when the pressure loss ΔP1 and ΔP2 of the refrigerant in the evaporators 15 and 18 are made smaller than the pressure increase amount PE by the ejector 14 (assuming ΔP1 and ΔP2 <PE), the average evaporation in the evaporators 15 and 18 is achieved. It becomes possible to make temperature lower than the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  In the ejector refrigeration cycle in which the evaporator 18 having a predetermined pressure loss is arranged on the suction side of the ejector 14, the refrigerant pressure loss ΔP <b> 2 in the evaporator 18 is greater than the pressure increase amount PE by the ejector 14 when the system is under a maximum load condition. Is set to be less.

  According to this, the pressure loss ΔP2 of the evaporator 18 at the suction side is made smaller than the pressure increase amount PE by the ejector 14 (assuming ΔP2 <PE), so that the average evaporation temperature in the evaporators 15 and 18 is the conventional one. It becomes possible to make it lower than an expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  Further, in the ejector refrigeration cycle in which the evaporator 15 having a predetermined pressure loss is disposed on the outflow side of the ejector 14, the refrigerant pressure loss ΔP <b> 1 in the evaporator 15 is greater than the pressure increase amount PE by the ejector 14 when the system is under a maximum load condition. Is set to be less.

  According to this, by making the pressure loss ΔP1 of the evaporator 15 on the outflow side smaller than the pressure increase amount PE by the ejector 14 (ΔP1 <PE), the pressure loss coefficient of the evaporators 15 and 18 is higher than that of the conventional evaporator. Even if it is large (see FIG. 4), the average evaporation temperature in the evaporator 15 on the outflow side can be made lower than that in the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  In the ejector refrigeration cycle, the second evaporator 18 having a predetermined pressure loss is disposed on the suction side of the ejector 14, and the first evaporator 15 having the predetermined pressure loss is disposed on the outflow side of the ejector 14. The first and second evaporators 15 and 18 are set so that the refrigerant pressure loss ΔP2 in the second evaporator 18 is smaller than the refrigerant pressure loss ΔP1 in the first evaporator 15 when the system is under the maximum load condition.

  According to this, the pressure loss ΔP2 of the second evaporator 18 on the suction side is made smaller than the pressure loss ΔP1 of the first evaporator 15 on the outflow side (ΔP2 <ΔP1), whereby the second loss on the suction side. The average evaporation temperature of the evaporator 18 can be made lower than that of the conventional expansion valve cycle. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  Moreover, the refrigerant | coolant flow path cross-sectional area of the evaporators 15 and 18 is set so that it may become the said setting. According to this, it can be set as the above-mentioned pressure relationship by manipulating the refrigerant | coolant flow path cross-sectional area of the evaporators 15 and 18 specifically. Moreover, the refrigerant | coolant flow path cross-sectional area of the evaporators 15 and 18 is set so that pressure loss (DELTA) P1 and (DELTA) P2 may be 100 kPa or less. According to this, the maximum boost amount max. This is because PE is about 100 kPa.

  Moreover, the refrigerant | coolant minimum flow path cross section of the evaporators 15 and 18 is set to 10 mm or more of hydraulic diameters. According to this, from the relationship between the hydraulic diameter of the refrigerant minimum flow path and the evaporator internal pressure loss shown in FIG. 15, the evaporator pressure losses ΔP1 and ΔP2 are set to the maximum of the ejector 14 at the maximum refrigerant flow rate at the maximum system load condition. Boosting amount max. This is because the hydraulic diameter in the refrigerant minimum flow path cross section needs to be 10 mm or more in order to suppress the PE below 100 kPa.

  In the ejector refrigeration cycle, the second evaporator 18 having a predetermined pressure loss is disposed on the suction side of the ejector 14, and the first evaporator 15 having the predetermined pressure loss is disposed on the outflow side of the ejector 14. The inlet throttle mechanisms 14a and 17 of the first and second evaporators 15 and 18 are set so that the refrigerant pressure Po2 at the outlet of the second evaporator 18 is equal to or lower than the refrigerant pressure Po1 at the outlet of the first evaporator 15. .

  According to this, since the ejector outflow refrigerant amount is larger than the ejector intake refrigerant amount, the average evaporation temperature of the suction side second evaporator 18 is made lower than the average evaporation temperature of the outflow side first evaporator 15. Is possible. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  Further, the distal end shape of the tube 21 inserted into the tank portions 15 b, 15 c, 18 b, and 18 c is a shape in which the central portion is recessed with respect to both end portions in the width direction of the tube 21. According to this, it becomes possible to increase the refrigerant flow path cross-sectional area in the tank portions 15b, 15c, 18b, 18c, and the refrigerant pressure loss of the first and second evaporators 15, 18 can be reduced, so that the cooling performance is improved. Can be improved.

  Further, the distal end shape of the tube 21 is formed so as to follow the outer shape of the ejector 14 disposed in the tank portions 15b, 15c, 18b, 18c. Moreover, it forms so that the front-end | tip shape of the tube 21 may follow the inner surface shape by the side of the tube insertion of tank part 15b, 15c, 18b, 18c.

  According to these, by forming the tip shape of the tube 21 along the outer shape of the ejector 14 or the inner surface shape of the tank portion 15b, 15c, 18b, 18c on the tube insertion side, the tank portions 15b, 15c, 18b , 18c can effectively increase the cross-sectional area of the refrigerant flow path.

(Second Embodiment)
11A shows an example in which a plurality of ejectors 14 are arranged in the tank portions 15b and 18b, FIG. 11B shows an example in which a plurality of ejectors 14 are arranged in the same tank portion 18b, and FIG. . As a feature different from the first embodiment described above, a plurality of ejectors 14 are arranged in the tank portions 15b and 18b.

  According to this, it is possible to increase the refrigerant flow path cross-sectional area in the tank portion by using a plurality of ejectors having a small diameter that can achieve the same effect, rather than arranging one ejector in the tank portion. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

  Furthermore, a plurality of ejectors 14 are arranged in the same tank portion 18b. According to this, even in the same tank part 18b, the refrigerant flow passage cross-sectional area in the tank part 18b is increased by using a plurality of ejectors with small diameters that can achieve the same effect, rather than arranging one ejector. It becomes possible to do. Therefore, the cooling performance can be reliably improved by increasing the temperature difference with the fluid to be cooled such as air.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be variously modified as described below.

  (1) FIGS. 12-14 is the schematic diagram of the ejector-type refrigerating cycle 10 in other embodiment. In each of the above-described embodiments, the ejector 14, the first evaporator 15, the throttle mechanism 17, and the second evaporator 18 are integrally configured as a heat exchanger unit. However, as shown in FIG. The refrigeration cycle apparatus may be configured separately.

  Moreover, as shown in FIG. 13, the accumulator 40 may be comprised between the 1st evaporator 15 and the compressor 11, and as shown in FIG. An internal heat exchanger 33 that exchanges heat between the refrigerant and the high-pressure refrigerant flowing out of the radiator 12 may be configured.

  (2) In the above-described embodiment, the temperature type expansion valve 13 is disposed on the refrigerant outflow side of the radiator 12. However, the temperature type expansion valve 13 may be omitted, or the electric type variable. A configuration using an expansion valve may also be used. Moreover, in the above-mentioned embodiment, although the temperature type expansion valve 13 and the temperature sensing part 13a were comprised separately from the heat exchanger unit, the temperature type expansion valve 13 and the temperature sensing part 13a were comprised. You may assemble to one.

  For example, the structure which accommodates the temperature type expansion valve 13 and the temperature sensing part 13a in the 1st connection block 23 of the integrated unit 20 is employable. In this case, the refrigerant inlet 25 is located between the liquid receiver 12 a and the temperature type expansion valve 13, and the refrigerant outlet 26 is located between the passage portion where the temperature sensing unit 13 a is installed and the compressor 11. .

  (3) In the above-described embodiment, the fixed ejector having the nozzle portion 14a having a constant passage area is illustrated as the ejector 14. However, as the ejector 14, a variable ejector having a variable nozzle portion capable of adjusting the passage area is used. May be. As a specific example of the variable nozzle section, for example, a needle is inserted into the passage of the variable nozzle section, and the position of the needle is controlled by an electric actuator or a mechanical temperature type variable throttle mechanism to adjust the passage area. A mechanism may be used.

  Further, in the above-described embodiment, the throttle mechanism 17 is configured by a fixed throttle such as a capillary tube or an orifice. However, the valve opening degree (passage throttle opening degree) of the throttle mechanism 17 can be adjusted by an electric actuator. An electric control valve may be used. Further, the throttle mechanism 17 may be configured by a combination of a fixed throttle such as a capillary tube or an orifice and an electromagnetic valve.

(4) In the above-described embodiment, the vapor compression subcritical cycle using a refrigerant such as a chlorofluorocarbon-based refrigerant or an HC-based refrigerant whose high pressure does not exceed the critical pressure has been described. However, carbon dioxide (CO ₂ ) is used as the refrigerant. Thus, the present invention may be applied to a vapor compression supercritical cycle using a refrigerant whose high pressure exceeds the critical pressure.

  However, in the supercritical cycle, the refrigerant discharged from the compressor is only dissipated in the supercritical state in the radiator 12, and does not condense. Therefore, in the liquid receiver 12a disposed on the high pressure side, the refrigerant gas-liquid separation action and The storage effect of the excess liquid refrigerant cannot be exhibited. Therefore, in the supercritical cycle, as shown in FIG. 13, a configuration may be adopted in which an accumulator forming a low-pressure side gas-liquid separator is disposed on the outlet side of the first evaporator 15.

  (5) In the above-described embodiment, the case where the space to be cooled of the first and second evaporators 15 and 18 is a vehicle interior space or a space inside a refrigerator-freezer of a refrigerator car has been described. Is widely applicable to refrigeration cycles for various uses such as stationary use, not limited to these vehicles.

It is a mimetic diagram of ejector type refrigeration cycle 10 for vehicles of an embodiment to which the present invention is applied. FIG. 2 is a ph diagram when the pressure increase amount PE of the ejector 14 is large in the vehicle ejector refrigeration cycle 10 of FIG. 1. FIG. 2 is a ph diagram when the pressure increase amount PE of the ejector 14 is small in the vehicle ejector refrigeration cycle 10 of FIG. 1. FIG. 2 is a ph diagram when the pressure loss coefficient of the evaporator is large in the vehicle ejector refrigeration cycle of FIG. 1. It is a perspective view which shows schematic structure of the integrated unit 20 in FIG. It is a cross-sectional view of the upper tank portions 15b, 18b of the integrated unit 20 of FIG. It is a longitudinal cross-sectional view of the upper tank part 18b of the integrated unit 20 of FIG. (A) is the example which made the front-end | tip shape of the tube 21 follow the external shape of the ejector 14, (b) is conventional. (A), (b) is the example which made the front-end | tip shape of the tube 21 follow the inner surface shape of the tube insertion side of the header tank part 18b. (A)-(c) is another example of the tip shape of tube 21. FIG. (A) is an example in which a plurality of ejectors 14 are arranged in the header tank portions 15b, 18b, (b) is an example in which a plurality of ejectors 14 are arranged in the same header tank portion 18b, and (c) is conventional. It is a schematic diagram of the ejector type | mold refrigerating cycle 10 in other embodiment. It is a schematic diagram of the ejector type | mold refrigerating cycle 10 in other embodiment. It is a schematic diagram of the ejector type | mold refrigerating cycle 10 in other embodiment. It is a graph which shows the relationship between the hydraulic diameter of a refrigerant | coolant minimum flow path, and the evaporator internal pressure loss.

Explanation of symbols

14 ... Ejector 14a ... Nozzle part (inlet throttle mechanism)
14b ... Refrigerant suction port 15 ... Upwind heat exchanger (evaporator, first evaporator)
15b, 15c ... Header tank 17 ... Throttle mechanism (inlet throttle mechanism)
18 ... leeward side heat exchange section (evaporator, second evaporator)
18b, 18c ... header tank 20 ... integrated unit (evaporator unit)
21 ... Tube Po1 ... Refrigerant pressure at the outlet of the first evaporator 15 Po2 ... Refrigerant pressure at the outlet of the second evaporator 18 PE ... Pressure increase amount of the ejector 14 ΔP1 ... Refrigerant pressure loss in the first evaporator 15 ΔP2 ... 2nd Pressure loss of refrigerant in the evaporator 18

Claims (7)

A first evaporator (15) having a predetermined pressure loss is arranged on the outlet side of the ejector (14);
In an ejector-type refrigeration cycle in which a second evaporator (18) having a predetermined pressure loss is arranged on the suction side of the ejector (14) ,
A refrigerant branch passage is branched from an inlet side of the ejector, a downstream side of the refrigerant branch passage is connected to a refrigerant suction port of the ejector, and the second evaporator is disposed in the refrigerant branch passage,
The system is set so that the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
The system is set so that the pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
When the system is under a maximum load condition, the refrigerant pressure loss (ΔP2) in the second evaporator (18) is smaller than the refrigerant pressure loss (ΔP1) in the first evaporator (15). 15) and the second evaporator (18) are set , an ejector-type refrigeration cycle. In addition, each of the first evaporator (15) and the second evaporator (18) includes an inlet throttle mechanism (14a, 17),
The inlet throttle mechanism (14a, 17) is set such that the refrigerant pressure (Po2) at the outlet of the second evaporator (18) is equal to or lower than the refrigerant pressure (Po1) at the outlet of the first evaporator (15). The ejector refrigeration cycle according to claim 1, wherein: The refrigerant was sucked from the refrigerant suction port (14b) by the high-speed refrigerant flow ejected from the nozzle part (14a), and sucked from the refrigerant jetted from the nozzle part (14a) and the refrigerant suction port (14b). An ejector (14) that mixes and discharges the refrigerant;
A first evaporator (15) disposed on the outlet side of the ejector (14) and having a predetermined pressure loss;
A second evaporator (18) disposed on the suction side of the ejector (14) and having a predetermined pressure loss ;
In the evaporator unit (20) in which the first evaporator (15), the second evaporator (18), and the ejector (14) are assembled together,
A refrigerant branch passage is branched from an inlet side of the ejector, a downstream side of the refrigerant branch passage is connected to a refrigerant suction port of the ejector, and the second evaporator is disposed in the refrigerant branch passage,
The system is set so that the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
The system is set so that the pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
When the system is under a maximum load condition, the refrigerant pressure loss (ΔP2) in the second evaporator (18) is smaller than the refrigerant pressure loss (ΔP1) in the first evaporator (15). 15) and the second evaporator (18) are set, and
The tip shape of the tube (21) inserted into the header tank portions (15b, 15c, 18b, 18c) of the first evaporator (15) and the second evaporator (18) is the same as that of the tube (21). An evaporator unit having a shape in which a central portion is recessed with respect to both end portions in the width direction. Claims tip shape of the tube (21), said header tank portion (15b, 15c, 18b, 18c), characterized in that it is formed along the outer shape of the ejector disposed within (14) Item 4. The evaporator unit according to Item 3 . 5. The evaporation according to claim 4 , wherein a tip shape of the tube (21) is formed along an inner surface shape of the header tank portion (15 b, 15 c, 18 b, 18 c) on the tube insertion side. Unit. The refrigerant was sucked from the refrigerant suction port (14b) by the high-speed refrigerant flow ejected from the nozzle part (14a), and sucked from the refrigerant jetted from the nozzle part (14a) and the refrigerant suction port (14b). An ejector (14) that mixes and discharges the refrigerant;
A first evaporator (15) disposed on the outlet side of the ejector (14) and having a predetermined pressure loss;
A second evaporator (18) disposed on the suction side of the ejector (14) and having a predetermined pressure loss ;
In the evaporator unit (20) in which the first evaporator (15), the second evaporator (18), and the ejector (14) are assembled together,
A refrigerant branch passage is branched from an inlet side of the ejector, a downstream side of the refrigerant branch passage is connected to a refrigerant suction port of the ejector, and the second evaporator is disposed in the refrigerant branch passage,
The system is set so that the pressure loss (ΔP1) of the refrigerant in the first evaporator (15) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
The system is set so that the pressure loss (ΔP2) of the refrigerant in the second evaporator (18) is smaller than the pressure increase (PE) by the ejector (14) when the system is under a maximum load condition,
When the system is under a maximum load condition, the refrigerant pressure loss (ΔP2) in the second evaporator (18) is smaller than the refrigerant pressure loss (ΔP1) in the first evaporator (15). 15) and the second evaporator (18) are set, and
An evaporator unit comprising a plurality of ejectors (14) disposed in header tank portions (15b, 18b) of the first evaporator (15) and the second evaporator (18) . The evaporator unit according to claim 6 , wherein the plurality of ejectors (14) are arranged in one header tank portion (18b).

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