JP6116810B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus including a compressor that compresses a refrigerant.

  As a compressor that compresses a refrigerant and circulates a refrigeration cycle, there is a compressor that is driven by an electric motor (see Patent Documents 1 and 2). Generally, this type of electric compressor controls the number of rotations based on the heat load of the refrigeration cycle. For example, the temperature of the evaporator provided in the refrigeration cycle is detected as an index of heat load, and the compressor is driven at the maximum number of revolutions until the evaporator temperature decreases and reaches the target temperature. At that point, the rotational speed is reduced.

JP 2010-126136 A JP 2011-126409 A

  Now, according to the above-described rotation speed control, the evaporator temperature is high immediately after the compressor is started, so that the control is performed at a high rotation speed (high rotation control). And when evaporator temperature falls to target temperature, it controls so that rotation speed may be reduced (low rotation control).

  However, high rotation control is performed even when the heat load is small, such as when the outside air temperature is close to the target air-conditioning temperature, because the change in the evaporator temperature is small (in FIG. 4A). The rotational speed immediately after startup greatly overshoots (see the dotted line in FIG. 4A). Therefore, it can be said that the conventional rotational speed control wastes power when the heat load is small. Moreover, since the operating sound of the compressor is easily heard by the user at the time of startup, there is a concern that if the high rotation control is performed at the time of startup, the operating sound becomes annoying.

  The above-mentioned problem is not limited to the electric compressor, and even in the case of the compressor driven by the output shaft of the internal combustion engine, the same problem occurs if the compressor has a function of changing the discharge capacity. . That is, at the time of starting the variable capacity compressor, there is a problem that the high-speed control is performed to waste the power of the internal combustion engine and the operation noise becomes annoying.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a refrigeration cycle apparatus that suppresses unnecessary power consumption and suppresses operating noise from becoming annoying.

The invention for achieving the above object is characterized by the following points. A compressor (11) that compresses refrigerant and circulates the refrigeration cycle (10);
Normal control means (S16) for controlling the discharge amount of the compressor;
High-pressure control means (S15) for feedback-controlling the discharge amount so that the refrigerant pressure on the high-pressure side of the refrigeration cycle becomes the target pressure;
With
The refrigeration cycle
A condenser (12) that dissipates heat of the high-pressure refrigerant discharged from the compressor;
An expansion valve (13) for reducing the pressure of the high-pressure refrigerant flowing out of the condenser;
A first evaporator (16) for evaporating the low-pressure refrigerant ;
A second evaporator (18) disposed downstream of the first evaporator (16) with respect to the blown air flow and evaporating the low-pressure refrigerant ;
It has a nozzle part (15a) for decompressing and expanding the intermediate-pressure refrigerant that has passed through the expansion valve, and sucks the vapor-phase refrigerant evaporated in the second evaporator (18) by the high-speed refrigerant flow injected from the nozzle part. An ejector (15) for converting the expansion energy of the refrigerant into pressure energy and flowing it to the first evaporator (16) to increase the suction pressure of the compressor;
An ejector-type refrigeration cycle comprising:
The normal control means (S16) controls the discharge amount according to the blown air temperature (Te) which is the temperature of the cold air cooled by the second evaporator (18),
The target pressure is set based on the outside air temperature at the time of starting or just before starting the compressor, and the cooling request load is less than the predetermined value during the period when the blown air temperature (Te) decreases from the start of starting the compressor to the predetermined temperature. As a condition, the discharge amount is controlled by the high-pressure control means so that the refrigerant pressure on the high-pressure side of the ejector refrigeration cycle becomes the target pressure.

  In short, in the present invention, when the required cooling load is less than the predetermined value, the discharge amount is feedback-controlled so that the high-pressure side refrigerant pressure (high-pressure side pressure) becomes the target pressure. For this reason, the discharge amount at the time of control by the normal control means, and the discharge amount at the start-up greatly overshoots the discharge amount after the evaporator temperature has sufficiently decreased (the discharge amount at the steady state). Can be avoided.

  For example, in the case of the electric compressor described above, since the rotational speed at startup is feedback-controlled according to the high pressure side pressure, it is possible to suppress overshooting of the rotational speed at startup relative to the rotational speed at steady state. . Further, in the case of a variable capacity compressor, since the discharge capacity at the start-up is feedback-controlled according to the high pressure side pressure, it is possible to suppress the discharge capacity at the start-up from overshooting the discharge capacity at the steady state. .

  Therefore, according to the said invention, the overshoot at the time of starting can be suppressed and useless power consumption can be suppressed. In addition, it is possible to reduce the operating noise of the compressor that is a concern at the time of startup, and to suppress the operating noise from being irritating to the user.

  Contrary to the above-described invention, when the feedback control according to the high-pressure side pressure is performed until the cooling required load is equal to or higher than the predetermined value, it is prevented that the evaporator temperature is rapidly lowered. Therefore, when quick cooling is requested immediately after startup, the request is hindered. In contrast, in the above invention, the feedback control according to the high pressure side pressure is performed when the cooling request load is less than the predetermined value, so that the request is hindered when quick cooling is required immediately after the start-up. Is avoided.

The block diagram of the refrigerating-cycle apparatus concerning one Embodiment of this invention. The flowchart which shows the procedure of the rotation speed control of the compressor shown in FIG. The time chart which shows the one aspect | mode at the time of implementing control of FIG. It is a figure explaining the effect by this invention, Comprising: (a) is a compressor rotation speed, (b) is power consumption, (c) is a figure which shows the change of blowing air temperature. The operation diagram of the refrigerating cycle shown in FIG. The figure explaining the change of the intermediate pressure at the time of implementing high pressure control. The figure which shows the various modifications of this invention.

  Hereinafter, an embodiment in which a refrigeration cycle apparatus according to the present invention is mounted on a vehicle will be described with reference to the drawings.

  As shown in FIG. 1, a vapor compression refrigeration cycle 10 according to this embodiment includes a compressor 11, a condenser 12, an expansion valve 13, a branching section 14, an ejector 15, and a first evaporator 16 that are annularly formed by a refrigerant pipe. Connected to. Further, the capillary 17 and the second evaporator 18 are connected to the downstream side of the branch portion 14 by a refrigerant pipe.

  The compressor 11 is a fluid machine that sucks the refrigerant flowing out from the first evaporator 16, compresses the refrigerant to high temperature and high pressure, and discharges the refrigerant to the condenser 12, and is driven by an electric motor 11a. The driving of the electric motor 11a is controlled by an electronic control unit (ECU 20). That is, the ECU 20 controls the number of times that the output shaft of the compressor 11 rotates per predetermined time (compressor rotational speed), and consequently the amount of refrigerant discharged from the compressor 11 per predetermined time (discharge amount). It can be said that it is in control.

  The condenser 12 is a heat exchanger that dissipates and cools the high-pressure refrigerant discharged from the compressor 11 by heat exchange with outside air that is forcibly blown by an electric fan (not shown). On the refrigerant outflow side of the condenser 12, a receiver (not shown) is provided that separates the gas-liquid of the cooled refrigerant and causes only the liquid refrigerant to flow out to the expansion valve 13 side.

  The expansion valve 13 is a throttle means for reducing the pressure of the high-pressure refrigerant flowing out from the condenser 12. The expansion valve 13 of the present embodiment detects the degree of superheat of the compressor suction side refrigerant based on the temperature and pressure of the suction side refrigerant of the compressor 11 so that the degree of superheat becomes a predetermined value set in advance. It is a temperature type expansion valve that adjusts the valve opening (refrigerant flow rate). The low-pressure refrigerant flowing out from the expansion valve 13 is distributed by the branching section 14 into a flow path that flows toward the nozzle section 15a of the ejector 15 and a flow path that flows toward the suction section 15b.

  The ejector 15 is a decompression means for decompressing the refrigerant, and is also a refrigerant circulation means (momentum transport pump) that circulates the refrigerant by a suction action (convolution action) of the refrigerant flow ejected at high speed. The ejector 15 is arranged in the same space as the nozzle portion 15a for further reducing and expanding the refrigerant by reducing the passage area of the refrigerant (intermediate pressure refrigerant) that has passed through the expansion valve 13, and the refrigerant outlet of the nozzle portion 15a. A suction part 15b for sucking a gas-phase refrigerant from the second evaporator 18 described later is provided.

  Furthermore, a mixing portion 15c that mixes the high-speed refrigerant flow from the nozzle portion 15a and the suction refrigerant of the suction portion 15b is provided on the downstream side of the refrigerant flow of the nozzle portion 15a and the suction portion 15b. And the diffuser part 15d which makes a pressure | voltage rise part is arrange | positioned in the refrigerant | coolant flow downstream of the mixing part 15c. The diffuser portion 15d is formed in a shape that gradually increases the passage area of the refrigerant, 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. The first evaporator 16 is connected to the outlet side of the diffuser portion 15 d of the ejector 15, and the outlet side of the first evaporator 16 is connected to the suction side of the compressor 11.

  On the other hand, a throttle mechanism 17 is disposed in the flow path that guides the refrigerant from the branch part 14 to the suction part 15 b side, 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 for adjusting the refrigerant flow rate to the second evaporator 18, and can be specifically constituted by a fixed throttle such as an orifice. An electric control valve whose valve opening (passage opening) can be adjusted by an electric actuator may be used as the throttle mechanism 17.

  The electric blower 19 blows air in the direction of the arrow (from top to bottom in FIG. 1), and the blown air is cooled by the two evaporators 16 and 18. The cold air cooled by the two evaporators 16 and 18 is sent to a common cooling target space (not shown), whereby the common cooling target space is cooled by the two evaporators 16 and 18.

  Next, the operation of the refrigeration cycle 10 having the above configuration will be described. When the compressor 11 is driven by the electric motor 11a, the high-temperature and high-pressure refrigerant compressed and discharged by the compressor 11 flows into the condenser 12. In the condenser 12, the high-temperature refrigerant is cooled by the outside air and condensed. The high-pressure refrigerant that has flowed out of the condenser 12 is gas-liquid separated in a receiver (not shown), and is decompressed by the expansion valve 13.

  The refrigerant flow branched from the expansion valve 13 toward the ejector 15 is decompressed and expanded by the nozzle portion 15a. Accordingly, the pressure energy of the refrigerant is converted into velocity energy at the nozzle portion 15a, and the refrigerant is ejected at a high velocity from the outlet of the nozzle portion 15a. Due to the refrigerant pressure drop at this time, the refrigerant (gas phase refrigerant) after passing through the second evaporator 18 is sucked from the suction part 15b.

  The refrigerant ejected from the nozzle portion 15a and the refrigerant sucked by the suction portion 15b are mixed in the mixing portion 15c on the downstream side of the nozzle portion 15a and flow into the diffuser portion 15d. In the diffuser portion 15d, 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 rises. Then, the refrigerant that has flowed out of the diffuser portion 15 d of the ejector 15 flows into the first evaporator 16. In the first evaporator 16, the low-temperature low-pressure refrigerant absorbs heat from the blown air and evaporates. The vapor phase refrigerant after evaporation is sucked into the compressor 11 and compressed again.

  On the other hand, the refrigerant flow branched from the expansion valve 13 toward the suction portion 15 b is decompressed by the throttle mechanism 17 to become low-pressure refrigerant, and this low-pressure refrigerant flows into the second evaporator 18. In the second evaporator 18, the low-temperature low-pressure refrigerant absorbs heat from the blown air after passing through the first evaporator 16 and evaporates. The vapor phase refrigerant after evaporation is sucked into the ejector 15 through the suction part 15b. According to the refrigeration cycle 10 configured as described above, the cool air cooled by both the first and second evaporators 16 and 18 is blown out to the space to be cooled (vehicle compartment) to cool (cool) the space to be cooled. ) You can do it.

  The ECU 20 receives signals from the blown air temperature sensor 21, the outside air temperature sensor 22, the temperature setting operation unit 23, and the high pressure sensor 24, and controls the operation of the electric blower 19 based on these signals to blow into the vehicle interior. The air volume of the conditioned air to be controlled, the outlets are switched, the compressor rotation speed is controlled to control the degree of cooling by the evaporators 16 and 18, and the temperature of the conditioned air is controlled.

  The blown air temperature sensor 21 detects the cold air temperature (blown air temperature Te) immediately after being cooled by the first and second evaporators 16 and 18. The outside air temperature sensor 22 detects the outside air temperature (outside air temperature). The temperature setting operation unit 23 outputs the set temperature operated by the occupant. The high-pressure sensor 24 is a refrigerant pressure on the high-pressure side in the refrigeration cycle, that is, a refrigerant pressure at an arbitrary point in the path from the discharge port of the compressor 11 to the inlet of the 13 expansion valve (hereinafter referred to as “high-pressure side pressure”). Is detected.

  Next, the control procedure of the compressor speed by the ECU 20 will be described with reference to FIG. Note that the processing in FIG. 2 is repeatedly performed at a predetermined cycle by a microcomputer included in the ECU 20, and is executed during the operation of the refrigeration cycle.

  First, in step S10, it is determined whether or not the cooling required load is in a low required load state that is less than a predetermined value. For example, if the air volume of the conditioned air blown into the passenger compartment, that is, the air volume of the electric blower 19 is less than a predetermined value, it is determined that the load is low. Alternatively, when the deviation between the outside air temperature and the room temperature is less than a predetermined value, or when the deviation between the outside air temperature and the set temperature is less than a predetermined value, the load is determined to be low.

  If it is determined that the load is not a low required load (S10: NO), the process proceeds to step S16 (normal control means), and “normal control” described below is performed on the compressor 11. That is, the target value Tetrg of the blown air temperature Te is set based on the set temperature, the room temperature, the outside air temperature, and the like. Then, the compressor rotational speed is fuzzy controlled so that the blown air temperature Te becomes the target value Tetrg. In this fuzzy control, control is performed without using the detection value of the high-pressure sensor 24. That is, the compressor speed is controlled regardless of the detected value of the high-pressure side pressure.

  When it is determined that the load is a low required load (S10: YES), in the subsequent step S11, it is determined whether or not the blown air temperature Te is less than a predetermined value. If Te <predetermined value is determined (S11: YES), normal control is performed in step S16, and if Te ≧ predetermined value is determined (S11: NO), high pressure control is performed in step S15 described later. . That is, immediately after the compressor 11 is started, the blown air temperature Te is not sufficiently lowered, so that the high pressure control is performed. After that, the normal control is performed after the blown air temperature Te is sufficiently lowered. .

  In step S12, it is determined whether or not a predetermined time has elapsed since the start of starting the compressor 11. If it is determined that it has not elapsed (S12: NO), in step S13, a target pressure (target high pressure) on the high pressure side is set based on the outside air temperature detected by the outside air temperature sensor 22. For example, the target high pressure is set with reference to a map indicated by reference numeral M1. Alternatively, the target high pressure may be calculated and set based on the outside air saturation pressure calculated based on the outside air temperature. For example, the target high pressure is calculated based on the following equation: target high pressure = (high pressure during steady operation−outside air saturation pressure) × K + outside air saturation pressure. The “K” is a constant of 0 or more and less than 1. The “high pressure during steady operation” means that a sufficient time has elapsed since the start of the compressor 11 and the state where the change in the blown air temperature Te is less than a predetermined value continues for a predetermined time or more during the normal operation. It is a pressure.

  On the other hand, if it is determined that the predetermined time has elapsed from the start of activation (S12: YES), in the subsequent step S14, the target high pressure is changed so as to gradually increase the target high pressure set in step S13. Then, in the next step S15, control (high pressure control) is performed so that the high pressure side pressure detected by the high pressure sensor 24 matches the target high pressure set in steps S13 and S14. In this control, feedback control of PI, PID, PD, etc. may be performed. In particular, it is desirable to perform PI or PID control having an integration operation to eliminate the residual deviation.

  As described above, when the control of FIG. 2 is performed, as shown in FIG. 3, the high pressure control is performed on the condition that the required cooling load is less than a predetermined value at the time t1 when the compressor 11 is started. The target high pressure is fixed at a constant value during a period from the start time t1 to a time t2 when a predetermined time elapses, and after the time t2, the high pressure control is performed while gradually increasing the target high pressure. Thereafter, at time t3 when the blown air temperature Te decreases to a predetermined value, the high pressure control is switched to the normal control.

  4 (a), 4 (b), and 4 (c) are diagrams showing a change in the rotational speed, a change in power consumption, and a change in the blown air temperature Te when the compressor 11 is started. A solid line in the figure indicates a high pressure. When the control is performed, the dotted line indicates the case where the normal control is performed. Also, the alternate long and short dash line in FIG. 4A indicates the compressor rotational speed (the rotational speed during steady operation) when the gradient of change in the blown air temperature Te is less than a predetermined value and is stable. In the example of FIG. 4A, in the case of normal control, the rotational speed at steady operation is at time t8, and in the case of high pressure control, the rotational speed at steady operation is at time t9.

  As shown in FIG. 4A, in the case of normal control, fuzzy control is performed to maximize the compressor speed immediately after startup (see t5 to t6). Thereafter, the compressor speed greatly overshoots the high pressure during steady operation until the time t8 when the rotational speed during steady operation stabilizes. On the other hand, in the case of high pressure control, feedback control is performed by setting the target high pressure to the same value as or lower than the high pressure during steady operation. Therefore, during the period from the start to the time t9 when the rotation speed is stabilized at the steady operation speed, there is almost no overshoot with respect to the steady operation rotation speed. Therefore, if high pressure control is performed, power consumption can be reduced as compared with the case of normal control (see FIG. 4B).

  However, when high pressure control is performed, the rate of decrease in the blown air temperature Te is slower than in the case of normal control (see FIG. 4C). In view of this point, in the present embodiment, since the high pressure control is performed on the condition that the load is low, the request is hindered by the execution of the high pressure control when quick cooling is required immediately after startup. Can be avoided.

  When the compressor is started, the vehicle is often stopped or traveling at a low speed. In this case, since the noise of the vehicle is low, the operation sound of the compressor 11 is likely to be annoying to the user. . With respect to this problem, according to the present embodiment, since the compressor rotation speed at the time of starting is suppressed, it is possible to reduce the operating sound of the compressor 11 which is a concern at the time of starting, and the operating sound is annoying to the user. Can be suppressed.

  Furthermore, according to this embodiment, the effects listed below are exhibited.

  The above-mentioned high pressure during steady operation has a different value depending on the cooling demand load at that time. Then, it is desirable to set the target high pressure to be equal to or lower than the high pressure during steady operation in order to suppress overshoot with respect to the rotational speed during steady operation. In the present embodiment in view of this point, the target high pressure is set based on the outside air temperature at the time of starting the compressor or immediately before starting the compressor. For this reason, it is possible to easily set the target high pressure to a value that can prevent the decrease rate of the blown air temperature Te from being unnecessarily slow while sufficiently suppressing the overshoot.

  -After starting the compressor, if the blown air temperature Te drops to a predetermined temperature, it can be considered that the above-mentioned steady operation has been performed, so there is little risk of overshoot even if normal control is performed. In this embodiment in view of this point, after starting the compressor, when the blown air temperature Te is lowered to a predetermined temperature, the control is switched from the control by the high pressure control means to the control by the normal control means. Therefore, it is possible to avoid continuing high pressure control more than necessary, and to switch to high-accuracy rotational speed control by normal control (fuzzy control).

  -Contrary to this embodiment, when the target high pressure is fixed to a constant value as shown in FIG. 7B, if the target high pressure is lower than the optimum value, the time elapses in the high pressure control period. Even so, there is a concern that the offset deviation is not eliminated and the blown air temperature Te does not decrease to a desired value. In the present embodiment in view of this point, a period in which the target pressure is gradually increased is provided in at least a part of the period in which the high pressure control is performed. In the example of FIG. 3, the target high pressure is gradually increased after time t2. Therefore, if time passes, it can ensure that the blowing air temperature Te falls to a desired value, and the said concern can be eliminated.

  As described above, the operation sound of the compressor 11 is likely to be annoying to the user at the time of startup. Then, as shown in FIG. 7 (c), when the target high pressure is increased from the start of activation, the rotation speed of the compressor 11 increases during a time period in which it is likely to be annoying, and the operating sound of the compressor 11 is given to the user. May be recognized. In the present embodiment in view of this point, the target high pressure is maintained at a constant value until a predetermined time elapses after the start of the compressor 11. Therefore, it can suppress that the rotation speed of the compressor 11 raises in the time slot | zone which is easy to become annoying, and can reduce a possibility that a user may recognize an operating sound.

  -In this embodiment, since this invention is applied to the refrigerating cycle provided with the ejector 15, it said that the pressure (intermediate pressure) of the refrigerant | coolant (intermediate pressure refrigerant | coolant) which passed the expansion valve 13 can be controlled to an optimal value. The effect is also demonstrated. Hereinafter, this effect will be described in detail.

  As shown in FIG. 5, the enthalpy and pressure of the refrigerant increase due to compression in the compressor 11 (point A → point B), and thereafter decrease due to heat dissipation in the condenser 12 (point B → point C). Thereafter, the pressure is reduced in an isoenthalpy state by the pressure reduction at the expansion valve 13 (point C → points D and F). Thereafter, the refrigerant flowing from the branching portion 14 toward the nozzle portion 15a is converted from velocity energy to pressure energy by the nozzle portion 15a, so that the pressure decreases as indicated by the symbol Gn and the enthalpy decreases as indicated by the symbol ΔH. (Point D → Point E). On the other hand, the pressure of the refrigerant that has flowed from the branching portion 14 toward the suction portion 15b decreases in a state of equal enthalpy due to the decompression by the throttle mechanism 17 (point F → point G).

  Here, the pressure at points A to C is called high pressure, the pressure at point D is called intermediate pressure, and the pressure at points E to A is called low pressure. The amount converted from velocity energy to pressure energy by the nozzle portion 15a, that is, the expansion energy in the nozzle portion 15a is a value obtained by multiplying the pressure drop amount Gn described above by the enthalpy drop amount ΔH. If this expansion energy can be acquired largely, it can be said that the ejector efficiency can be improved and the cycle efficiency of the refrigeration cycle 10 can be improved.

  As shown in FIG. 6, the expansion energy becomes maximum when the intermediate pressure is a predetermined value (optimum value Pa). Further, it is desirable to control the high pressure by controlling the compressor speed so that the intermediate pressure and the high pressure are highly correlated and the intermediate pressure is in the vicinity of the optimum value Pa. And if normal control is implemented at the time of starting, an intermediate pressure will raise to the code | symbol P3 with a high pressure raise. Thereafter, the intermediate pressure decreases to the symbol P1 as the rotational speed decreases. That is, the intermediate pressure changes in the range of the sign W1. On the other hand, if high pressure control is performed at the time of start-up, since the increase in high pressure is suppressed, the intermediate pressure rises only up to symbol P2, and thereafter the intermediate pressure falls to symbol P1 as the rotational speed decreases. That is, the intermediate pressure changes in the range of the sign W2.

  As described above, according to the present embodiment in which the high pressure control is performed, it is possible to suppress the intermediate pressure from greatly changing from the optimum value Pa that maximizes the expansion energy. Therefore, since the expansion | swelling energy fall at the time of starting can be suppressed, ejector efficiency can be improved and the cycle efficiency of the refrigerating cycle 10 can be improved.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In the above embodiment, the target high pressure is changed as shown in FIG. 7A, but the target high pressure may be fixed to a constant value as shown in FIG. 7B. Further, as shown in FIG. 7B, the target high pressure may be increased from the start of activation. Moreover, as shown in FIG.7 (d), environmental parameters, such as external temperature, may be acquired sequentially and a target high pressure may be changed sequentially according to the acquired value.

  In the above embodiment, the target high pressure is set according to the outside air temperature. However, the high pressure during steady operation or the rotation speed during steady operation is predicted based on the outside air temperature, and the target high pressure is set according to the predicted value. It may be.

  The compressor according to the present invention is not limited to the electric compressor 11 shown in FIG. 1, and may be an engine-driven compressor as long as it is a variable capacity type. For example, a swash plate type variable displacement type which is an engine drive type in which a compressor is driven to rotate by a vehicle running engine and the discharge capacity can be continuously changed from 100% to near 0% by adjusting the pressure of the swash plate chamber. Compressors. In the case of the electric compressor 11, the rotational speed is controlled, whereas in the case of a variable capacity compressor, the discharge amount may be controlled by controlling the swash plate angle.

  In the above embodiment, the control is switched from the high pressure control to the normal control at the timing when the blown air temperature Te is lowered to the predetermined value. However, the temperature of the evaporators 16 and 18 is directly detected, and the detected value becomes the predetermined value. You may make it switch to normal control at the timing which fell to. Or you may make it switch to normal control at the timing which the pressure (low pressure) of the low voltage | pressure side of the refrigerating cycle 10 rose to the predetermined value.

  DESCRIPTION OF SYMBOLS 10 ... Refrigeration cycle, 11 ... Compressor, 16, 18 ... Evaporator, S15 ... High pressure control means, S16 ... Normal control means

Claims (5)

A compressor (11) for compressing the refrigerant and circulating the refrigeration cycle (10);
Normal control means (S16) for controlling the discharge amount of the compressor;
High-pressure control means (S15) for feedback-controlling the discharge amount so that the refrigerant pressure on the high-pressure side of the refrigeration cycle becomes a target pressure;
With
The refrigeration cycle is
A condenser (12) that dissipates heat of the high-pressure refrigerant discharged from the compressor;
An expansion valve (13) for depressurizing the high-pressure refrigerant flowing out of the condenser;
A first evaporator (16) for evaporating the low-pressure refrigerant ;
A second evaporator (18) disposed downstream of the first evaporator (16) with respect to the blown air flow and evaporating the low-pressure refrigerant ;
It has a nozzle part (15a) for decompressing and expanding the intermediate-pressure refrigerant that has passed through the expansion valve, and the vapor-phase refrigerant evaporated in the second evaporator (18) by the high-speed refrigerant flow injected from the nozzle part. An ejector (15) for sucking, converting expansion energy of the refrigerant into pressure energy and flowing it out to the first evaporator (16) to increase the suction pressure of the compressor;
An ejector-type refrigeration cycle comprising:
The normal control means (S16) controls the discharge amount according to the blown air temperature (Te) which is the temperature of the cold air cooled by the second evaporator (18),
The target pressure is set based on the outside air temperature at the time of starting or just before starting the compressor, and during the period when the blown air temperature (Te) decreases from the start time of starting the compressor to a predetermined temperature, the cooling required load The refrigeration cycle apparatus is characterized in that the discharge amount is controlled by the high pressure control means so that the refrigerant pressure on the high pressure side of the ejector refrigeration cycle becomes the target pressure on the condition that is less than a predetermined value.   The cooling requirement load is less than a predetermined value means that the amount of conditioned air blown into the vehicle interior is less than the predetermined value, or the deviation between the outside air temperature and the room temperature is less than the prescribed value, or the deviation between the outside air temperature and the set temperature. The refrigeration cycle apparatus according to claim 1, wherein is less than a predetermined value. The control is switched from the control by the high-pressure control means to the control by the normal control means at the time when the blown air temperature (Te) is lowered to be lower than the predetermined temperature after the compressor is started. Item 3. The refrigeration cycle apparatus according to Item 1 or 2.   The refrigeration according to any one of claims 1 to 3, wherein a period set so as to gradually increase the target pressure is provided in at least a part of a period during which the control by the high-pressure control means is performed. Cycle equipment.   5. The apparatus according to claim 1, wherein the target pressure is set to a fixed value until a predetermined time elapses after starting the compressor. Refrigeration cycle equipment.

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