JP2003035458A - Refrigerating cycle equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the penetration of air into a compressor due to a turn of the inlet pressure of a compressor into a negative one and also to reduce a delay of the start of a heating function. SOLUTION: Refrigerating cycle equipment is so constituted that a refrigerant cycle (C) for cooling wherein an indoor heat exchanger 18 is operated as an evaporator and a hot gas heater cycle (H) for heating wherein a refrigerant discharged from the compressor 10 is returned thereto through the indoor heat exchanger 18, being passed around an outdoor heat exchanger 14, so as to make the indoor heat exchanger 18 operate as a radiator can be switched over to each other. When a physical quantity relating to the inlet pressure of the compressor 10 is a prescribed value or below on the occasion of starting up the hot gas heater cycle H in this equipment, the compressor 10 is operated intermittently for a prescribed time, so as to restrict the discharge capacity of the compressor 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a compressor discharge gas refrigerant (hot gas) for indoor heat exchanger (evaporator) during heating.
The present invention relates to a refrigeration cycle device that exhibits a hot gas heating function by using the indoor heat exchanger as a radiator of a gas refrigerant by directly introducing it into the air conditioner, and is suitable as a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, hot water (engine cooling water) is circulated in a heating heat exchanger during heating in winter,
In this heating heat exchanger, hot water is used as a heat source to heat the conditioned air. In this case, when the temperature of the hot water is low, such as when the engine is started, the temperature of the air blown into the vehicle interior may decrease and the required heating capacity may not be obtained.

Therefore, a refrigerating cycle device capable of exhibiting a heating function by a hot gas heater cycle has been conventionally proposed. In this conventional device, when the hot water temperature is lower than a predetermined temperature such as when the engine is started, the compressor discharge gas refrigerant (hot gas) bypasses the condenser and is introduced into the evaporator, and the evaporator discharges the gas refrigerant from the conditioned air. By radiating heat to, the heating function can be exerted.

By the way, during the cold season in winter, the refrigeration cycle may be started under an extremely low temperature condition such that the outside air temperature becomes, for example, −20 ° C. or less. Since the saturation pressure determined by the outside air temperature is very low, the cycle internal pressure (that is, the refrigerant saturation pressure) before starting the refrigeration cycle is also very low. Therefore, when the compressor of the refrigeration cycle is started, the suction pressure of the compressor becomes negative, and air may enter the inside of the compressor through the shaft seal portion of the compressor.

Therefore, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 12-142.
Japanese Patent Publication No. 094 discloses that in a refrigeration cycle device that exhibits a heating function by a hot gas heater cycle, the compressor suction pressure is detected, and when the compressor suction pressure is equal to or higher than a predetermined value, the compressor is started, and the compressor suction pressure is detected. It has been proposed to employ a control method of stopping the compressor when is lower than a predetermined value to prevent air from entering the compressor from the shaft seal portion.

[0006]

However, according to the prior art of the above publication, when the suction pressure of the compressor is lower than a predetermined value, the compressor is stopped and the compressor is not started. Therefore, the heating function by the hot gas heater cycle is used. There is a problem that the heating function cannot be activated and the startup of the heating function is delayed.

In view of the above points, it is an object of the present invention to prevent the inhalation pressure of the compressor from becoming a negative pressure and to prevent the air from entering the inside of the compressor, and to suppress the delay in the startup of the heating function. To do.

[0008]

In order to achieve the above object, in the invention described in claim 1, the refrigerant discharged from the compressor (10) is supplied to the outdoor heat exchanger (14) and the cooling decompressor ( 16) and the indoor heat exchanger (18) to return to the compressor (10), and thereby the refrigeration cycle (C) for cooling, which operates the indoor heat exchanger (18) as an evaporator, and discharge from the compressor (10). The separated refrigerant is transferred to the outdoor heat exchanger (14).
Is bypassed and returned to the compressor (10) through the indoor heat exchanger (18) so that the heating hot gas heater cycle (H) that operates the indoor heat exchanger (18) as a radiator can be switched. In the above refrigeration cycle apparatus, when the hot gas heater cycle (H) is started and the physical quantity related to the suction pressure of the compressor (10) is equal to or less than a predetermined value, the discharge capacity of the compressor (10) is limited. The compressor (10) is operated for a predetermined time.

According to this, when the suction pressure of the compressor is lower than the predetermined value, the discharge capacity of the compressor (10) can be limited to operate the compressor (10). By limiting the discharge capacity of the compressor, the decrease in the suction pressure of the compressor is suppressed,
It is possible to prevent air from entering the inside of the compressor due to a decrease in the suction pressure of the compressor. Therefore, it is not necessary to take measures such as specially improving the sealing performance of the shaft seal portion of the compressor (10).

Although the discharge capacity of the compressor is limited,
Since the compressor (10) is operated even when the outside temperature is extremely low, it is possible to minimize the delay in starting the heating function when the outside temperature is extremely low.

According to the invention of claim 2, claim 1
The discharge capacity is specifically limited by the compressor (10).
Can be performed by intermittently operating.

Further, as in the invention described in claim 3, in claim 1, the compressor (10) is a variable displacement compressor provided with a variable displacement mechanism for varying the discharge displacement, and the variable displacement compressor. The ejection capacity may be limited by setting the ejection capacity in (10) to a predetermined capacity smaller than the maximum capacity.

As in the invention described in claim 4, the outside air temperature can be used as the physical quantity related to the suction pressure of the compressor (10).

Further, as in the invention of the fifth aspect, both the outside air temperature and the rotation speed of the compressor (10) may be used as the physical quantity related to the suction pressure of the compressor (10). .

According to this, it is possible to more appropriately determine whether or not it is necessary to limit the discharge capacity of the compressor (10) by using both the outside air temperature and the rotation speed of the compressor (10).

According to the invention described in claim 6, if the time for keeping the discharge capacity of the compressor (10) limited (the predetermined time in claim 1) is lengthened according to the decrease of the outside air temperature, The discharge capacity limit can be appropriately determined according to the temperature.
The effect of suppressing a decrease in the compressor suction pressure according to the first aspect can be more effectively exhibited.

According to a seventh aspect of the present invention, there is provided a refrigeration cycle apparatus mounted on a vehicle, wherein the compressor (10) is driven by a vehicle engine (12), and the indoor heat exchanger (1
8) is arranged in an air-conditioning case (22) that constitutes a passage for air blown into the vehicle compartment, and inside the air-conditioning case (22), the vehicle engine (12) is provided downstream of the indoor heat exchanger (18). A hot water heat exchanger (24) for heating air using hot water as a heat source is arranged.

As described above, the refrigerating cycle for a vehicle which exhibits a heating effect by the combination of the hot water heat exchanger (24) for heating the air with the hot water heat source and the indoor heat exchanger (18) for heating the air with the hot gas. In the device, the present invention can be preferably implemented.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a first embodiment in which the present invention is applied to a refrigeration cycle device in a vehicle air conditioner. The compressor 10 is driven by a water-cooled vehicle engine 12 via an electromagnetic clutch 11.

The discharge side of the compressor 10 is connected to a condenser 14 via a cooling solenoid valve 13, and the outlet side of the condenser 14 is a liquid receiver 15 for separating the gas-liquid refrigerant and storing the liquid refrigerant. Connected. The condenser 14 is an outdoor heat exchanger that is disposed in the vehicle engine room together with the compressor 10 and the like and exchanges heat with the outside air (cooling air) blown by the electric cooling fan 14a.

The outlet side of the liquid receiver 15 is connected to a temperature type expansion valve 16 which constitutes a cooling decompression device. The outlet side of the thermal expansion valve 16 is connected to an evaporator 18 via a check valve 17. The outlet side of the evaporator 18 is connected to the suction side of the compressor 10 via an accumulator 19.

From the discharge side of the compressor 10 described above, the electromagnetic valve 13 for cooling, the condenser 14, the liquid receiver 15 and the thermal expansion valve 16
-> Check valve 17-> Evaporator 18-> The closed circuit that returns to the suction side of the compressor 10 via the accumulator 19 constitutes a normal refrigeration cycle C for cooling.

As is well known, the temperature type expansion valve 16 adjusts the valve opening (refrigerant flow rate) so that the superheat degree of the refrigerant at the outlet of the evaporator 18 is maintained at a predetermined value during the normal refrigeration cycle operation (in the cooling mode). To do. The accumulator 19 separates the gas and liquid of the refrigerant to store the liquid refrigerant, and sucks the gas refrigerant and a small amount of the liquid refrigerant (in which oil is dissolved) near the bottom to the compressor 10 side.

On the other hand, a hot gas bypass passage 20 for bypassing the condenser 14 and the like is provided between the discharge side of the compressor 10 and the inlet side of the evaporator 18, and this bypass passage 2
At 0, a solenoid valve 21 for heating and a throttle 21a constituting a pressure reducing device for heating are provided in series. This diaphragm 21a can be constituted by a fixed diaphragm such as an orifice or a capillary tube. Solenoid valve 2 for heating from the discharge side of the compressor 10.
A hot gas heater cycle H for heating is constituted by a closed circuit which returns to the suction side of the compressor 10 via 1 → throttle 21a → evaporator 18 → accumulator 19.

The air conditioner case 22 of the vehicle air conditioner constitutes an air passage through which air flows toward the passenger compartment, and an inside / outside air switching box (not shown) is provided on the suction side of the electric air conditioner blower 23. The air (vehicle compartment air or outside air) installed and introduced into the inside / outside air switching box is blown in the air conditioning case 22 by the operation of the air conditioning blower 23. The evaporator 18 is an indoor heat exchanger installed in the air conditioning case 22, and the refrigerant circulates by the refrigeration cycle C in the cooling mode, and the refrigerant is evaporated (heat absorption) in the evaporator 18 to cause the air conditioner blower 23 to cool. The blown air is cooled. Further, in the heating mode, the evaporator 18 serves as a radiator because the high-temperature refrigerant gas (hot gas) from the hot gas bypass passage 20 flows in to heat the air.

In the air conditioning case 22, a hot water type heat exchanger 24 for heating is provided downstream of the evaporator 18 on the air downstream side to heat the blown air using hot water (engine cooling water) from the vehicle engine 12 as a heat source. The conditioned air is blown into the passenger compartment from an outlet (not shown) provided on the downstream side of the heating heat exchanger 24. In the hot water circuit to the heating heat exchanger 24, a hot water valve 2 for controlling the hot water flow is provided.
5 is provided.

Electronic control unit for air conditioning (hereinafter referred to as ECU)
Reference numeral 26 is composed of a microcomputer and its peripheral circuits, performs arithmetic processing according to a preset program, opens and closes the solenoid valves 13 and 21 for cooling and heating, and other electric devices (11, 14a, 23, 25). Etc.) operation is controlled.

FIG. 2 is a block diagram of an electric control unit including the ECU 26, which is provided with sensors 27a to 27f for detecting air conditioning environmental factors necessary for automatically controlling the air conditioning in the vehicle compartment. The detection signal is input to the ECU 26. These sensors are, specifically, the cooling water temperature sensor 27a that detects the temperature of the cooling water flowing into the hot water heat exchanger 24, the outside air temperature sensor 27b, and the evaporation that detects the air temperature immediately after passing through the evaporator 18. A device outlet temperature sensor 27c, a refrigerant pressure sensor (high pressure detection means) 27d for detecting a high pressure (discharge pressure: Pd) of the refrigeration cycle,
The inside air temperature sensor 27e detects an air temperature inside the vehicle compartment (hereinafter referred to as the inside air temperature), and the solar radiation sensor 27f detects an amount of solar radiation incident on the inside of the vehicle compartment.

Further, various operation switch groups 29a to 29f on the air conditioning operation panel 28 installed near the instrument panel in the passenger compartment.
The switch operation signal from is input to the ECU 26. As this operation switch group, specifically, an air conditioner switch 29a for instructing start or stop of the compressor 10 of the refrigeration cycle is installed.
“A” functions as a cooling switch that sets the cooling mode.

Further, on the air conditioning operation panel 28, a hot gas heating switch 29b for setting a heating mode by a hot gas heater cycle, a blowout mode changeover switch 29c for switching a blowout mode of air conditioning, and a temperature inside the passenger compartment are set to desired temperatures. Temperature setting switch (temperature setting means) 29
d, a blower switch 29e for instructing on / off of the blower 23 and air volume switching, an inside / outside air switching switch 29f for instructing switching of the outside air introduction mode and the inside air circulation mode in the inside / outside air switching box, etc. are installed.

In FIG. 2, 14b is a drive motor of the condenser cooling fan 14a, and 23a is a blower motor of the air conditioning blower 23.

Next, the operation of the first embodiment having the above structure will be described. First, the operation of the refrigeration cycle portion will be described. In the cooling mode, the ECU 26 opens the cooling electromagnetic valve 13 and opens the heating electromagnetic valve 21. Therefore, when the electromagnetic clutch 11 is in the connected state and the compressor 10 is driven by the vehicle engine 12, the gas refrigerant discharged from the compressor 10 passes through the cooling electromagnetic valve 13 in the open state and flows into the condenser 14. .

In the condenser 14, the refrigerant is cooled and condensed by the outside air blown by the cooling fan 14a. Then, the refrigerant that has passed through the condenser 14 is separated into gas and liquid by the liquid receiver 15, and only the liquid refrigerant is decompressed by the thermal expansion valve 16 to be in a low temperature and low pressure gas-liquid two-phase state.

Next, the low-pressure refrigerant passes through the check valve 17, flows into the evaporator 18, and absorbs heat from the conditioned air blown by the blower 23 to be evaporated. The conditioned air cooled by the evaporator 18 is blown into the vehicle interior to cool the vehicle interior. Evaporator 1
The gas refrigerant evaporated in 8 is sucked into the compressor 10 via the accumulator 19 and compressed.

During the heating mode in winter, the ECU 26 closes the cooling solenoid valve 13 and the heating solenoid valve 21.
Is opened and the hot gas bypass passage 20 is opened. Therefore, the high-temperature discharge gas refrigerant (superheated gas refrigerant) of the compressor 10 passes through the heating solenoid valve 21 in the open state and the throttle 21
After being decompressed by a, it flows into the evaporator 18.

At this time, the check valve 17 prevents the gas refrigerant from the hot gas bypass passage 20 from flowing through the thermal expansion valve 16 to the condenser 14 side. Therefore, the refrigeration cycle is operated in a closed circuit (hot gas heater cycle H) that returns to the discharge side of the compressor → the heating electromagnetic valve 21 → the throttle 21a → the evaporator 18 → the accumulator 19 → the suction side of the compressor 10. .

The superheated gas refrigerant, which has been decompressed by the throttle 21a, radiates heat to the blast air in the evaporator 18 to heat the blast air. Here, the amount of heat released from the gas refrigerant in the evaporator 18 corresponds to the amount of compression work of the compressor 10. At this time, by blowing hot water of the engine 12 through the hot water type heat exchanger 24 for heating through the hot water valve 25, the blown air can be further heated in the heat exchanger 24, and the hot air is blown into the vehicle interior. be able to. The gas refrigerant radiating heat in the evaporator 18 is sucked into the compressor 10 via the accumulator 19 and compressed.

When the temperature of the hot water of the engine 12 is low, even if the compressor 10 operates, the warm-up control for stopping the blower 23 can be performed to prevent the low-temperature air from blowing into the passenger compartment.

Next, the characteristic operation of the first embodiment will be described with reference to the flow chart of FIG. FIG. 3 shows the ECU 26
Is a control routine executed by the vehicle engine 1
The engine 12 when the ignition switch 2 is turned on
When is started, the routine of FIG. 3 starts. First, in step S10, switch operation signals from the operation switches 29a to 29f on the air conditioning operation panel 28 are read. Next, in step S20, the sensors 27a to 27 are
Various sensor signals from f are read.

Next, in step S30, it is determined whether or not the hot gas switch 29b is turned on (ON), that is, whether or not the hot gas heating mode is set. When the hot gas switch 29b is OFF, the process proceeds to step S40, the energization of the electromagnetic clutch 11 is stopped (OFF), and the compressor 10 is stopped.

On the other hand, the hot gas heating switch 2
If 9b is ON, the process proceeds to step S50, and it is determined whether the engine water temperature TW detected by the water temperature sensor 27a is equal to or lower than a predetermined temperature T1 (for example, 80 ° C.). The predetermined temperature T1 is a temperature for determining whether or not the heating capacity of the hot water heat source in the heater core 24 is at a level required for heating the passenger compartment, and when the engine water temperature TW is higher than the predetermined temperature T1 (80 ° C.). Since the heating capacity of the hot water heat source in the heater core 24 has reached the level required for heating the vehicle interior, the heating operation by the hot gas heater cycle H is unnecessary.

Therefore, when the determination in step S50 is NO, the process proceeds to step S40, the energization of the electromagnetic clutch 11 is stopped (OFF), and the compressor 10 is stopped.
On the other hand, when the determination in step S50 is YES, it means that the heating operation by the hot gas heater cycle H is necessary, and therefore, in step S60, the outside air temperature TAM detected by the outside air temperature sensor 27b is predetermined. Temperature T
It is determined whether the temperature is 2 (for example, -15 ° C) or less.

Here, the outside air temperature TAM determined in step S60 is one of the physical quantities related to the suction pressure of the compressor 10.
Is one. That is, the pressure of the refrigerant enclosed in the refrigeration cycle is the ambient temperature before the compressor 10 is started, that is,
Since the saturation pressure is determined by the outside temperature TAM,
By detecting the outside air temperature TAM, the refrigerant pressure in the cycle before the compressor is started, that is, the compressor suction pressure can be determined.

When the refrigerant is R134a, the outside temperature TAM =
Since the atmospheric pressure (0 MPaG) is obtained at −26 ° C., if the predetermined temperature T2 is set to −15 ° C., for example, the pressure of the refrigerant in the cycle before the compressor is started is slightly higher than the atmospheric pressure (0.7 MPaG). ) Can be determined.

Therefore, in step S60, the outside temperature TAM
Is higher than the predetermined temperature T2, the suction pressure of the compressor is slightly higher than the atmospheric pressure, so that there is no possibility that air will enter the inside of the compressor 10 when the compressor 10 is started. Therefore, the process proceeds from step S60 to step S70, and the electromagnetic clutch 11 is continuously energized (ON) to start the compressor 10. That is, the discharge capacity of the compressor 10 is not limited. At this time, the cooling solenoid valve 13 is closed, the heating solenoid valve 21 is opened, and the heating operation by the hot gas heater cycle H is executed.

On the other hand, when it is determined in step S60 that the outside air temperature TAM is equal to or lower than the predetermined temperature T2, it means that the compressor suction pressure is about the same as or lower than the atmospheric pressure, and therefore the compressor 10 It is possible that the suction pressure of the compressor becomes a negative pressure due to the activation of and the air enters the inside of the compressor 10. Therefore, in this case, the process proceeds from step S60 to step S80, and compressor start control for preventing air intrusion, that is, the compressor 10 is kept for a predetermined time t0,
The discharge capacity of the compressor 10 is limited by forcibly controlling the on / off (ON-OFF).

The intermittent control at the time of starting the compressor in step S80 will be specifically described with reference to FIG. 4. The intermittent control at the time of starting the compressor is performed during a predetermined time t0 after the start of the compressor. The intermittent control repeats turning on and off the compressor 10 (electromagnetic clutch 11) at predetermined time intervals. In the example of FIG. 4, ON time of the compressor 10 (electromagnetic clutch 11) = 10 seconds, OFF for a predetermined time t0 = 1 minute
The time is set to 5 seconds, and the ON and OFF are repeated.

FIG. 4 shows a change in the compressor suction pressure after the compressor 10 is started under the conditions of the outside air temperature TAM = −15 ° C. and the rotation speed of the compressor = 5000 rpm. A shows the case where the intermittent control at the time of starting the compressor is carried out in step S80, while the broken line B shows the case where the intermittent control at the time of starting the compressor is not carried out.
That is, this is a case where the compressor 10 is simply and continuously started.

In the case of the broken line B, the suction pressure of the compressor decreases to a pressure below the lower limit of operation (-0.05 MPaG) of the compressor 10, causing problems such as air intrusion into the compressor. On the other hand, according to the first embodiment, since the intermittent control at the time of starting the compressor in step S80 is performed, the compressor suction pressure after the compressor is started is equal to the atmospheric pressure (0 MPa).
It only drops to a pressure slightly below G).
Therefore, it is possible to prevent the compressor suction pressure from decreasing to the above-mentioned lower limit of operation, so that it is possible to prevent problems such as air intrusion into the compressor.

Moreover, even at an extremely low outside temperature such that the outside temperature TAM ≦ −15 ° C., since the compressor 10 is started by the intermittent control, the heating function by the hot gas heater cycle does not remain stopped. Even if the heating capacity is limited to some extent at startup, the heating function by the hot gas heater cycle can be started at the same time as the hot gas heating switch 29b is turned on. Therefore, it is possible to minimize the delay in starting the heating function of the vehicle.

(Second Embodiment) In the first embodiment,
Although the necessity of the intermittent control at the time of starting the compressor in step S80 is determined only by the outside air temperature TAM, the compressor suction pressure has a great influence on the rotation speed of the compressor 10 in addition to the outside air temperature TAM. Therefore, in the second embodiment, the necessity of the intermittent control at the time of starting the compressor is determined based on both the outside air temperature TAM and the compressor rotation speed.

FIG. 5 is a characteristic diagram showing a method of determining the necessity of the intermittent control at the time of starting the compressor according to the second embodiment. The intermittent control is performed in the left side region of the partition line C (low temperature outside temperature region). In the area, the area on the right side of the partition line C (the area on the high temperature side of the outside air temperature) is the area without the intermittent control. Since the compressor suction pressure decreases as the compressor rotation speed increases, the outside air temperature range that requires intermittent control at the time of starting the compressor is expanded to the high temperature side as the compressor rotation speed increases.

As a result, in addition to the outside air temperature TAM, the compressor 1
The necessity of the intermittent control at the time of starting the compressor can be more appropriately determined in consideration of the number of revolutions of zero.

(Third Embodiment) In the first embodiment,
Although the intermittent control at the time of starting the compressor in step S80 is executed for a predetermined time t0 (for example, 1 minute) set in advance after being started, in the third embodiment, the intermittent control at the time of starting the compressor is executed. A predetermined time t0 in which the time is preset
It is designed to be variable instead of being fixed to.

FIG. 6 shows a method for determining the execution time of the compressor on / off control according to the third embodiment.
There is a correlation that the lower is the suction pressure of the compressor. Therefore, in the third embodiment, as shown in FIG. 6, the execution time of the intermittent control at the time of starting the compressor is lengthened as the outside air temperature TAM decreases. Thereby, the execution time of the compressor on / off control can be set to an appropriate time according to the level of the outside air temperature TAM.

(Fourth Embodiment) In the first embodiment,
In the intermittent control at the time of starting the compressor in step S80, the ON time of the compressor 10 (electromagnetic clutch 11) = 10
Although the intermittent time of the compressor 10 is fixed to a fixed time of 2 seconds, OFF time = 5 seconds, in the fourth embodiment, the intermittent time of the compressor 10 is variable instead of being constant. .

That is, in the fourth embodiment, the compressor 10
The intermittent time of is changed so that the compressor operating rate decreases as the outside air temperature TAM decreases. Specifically, the compressor ON time is shortened as the outside air temperature TAM decreases.
The compressor OFF time is lengthened as the outside air temperature TAM decreases. Compressor O as the outside air temperature TAM decreases
Shorten N time and lengthen compressor OFF time. Any of Thereby, the compressor 10
Can be set to an appropriate time depending on whether the outside air temperature TAM is high or low.

(Fifth Embodiment) In the first embodiment,
The case of the fixed capacity type in which the discharge capacity is constant as the compressor 10 has been described. However, in the fifth embodiment, a variable capacity type compressor having a capacity varying mechanism for varying the discharge capacity is used as the compressor 10. To use. Then, step S8
In the control at the time of starting the compressor by 0, instead of the intermittent control of the compressor 10, the discharge capacity of the variable capacity compressor 10 is set to a predetermined capacity smaller than the maximum capacity, and the compressor 10
Is operated for a predetermined time in a small capacity state.

Also by this, it is possible to prevent a decrease in the suction pressure of the compressor at an extremely low outside temperature and prevent air from entering the inside of the compressor.

As the variable displacement compressor 10, a well-known swash plate type variable displacement compressor or the like which adjusts the inclination angle of the swash plate to change the piston stroke to vary the discharge capacity can be used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vehicle refrigeration cycle apparatus showing a first embodiment of the present invention.

FIG. 2 is a block diagram of an electric control unit according to the first embodiment.

FIG. 3 is a flowchart showing the operation of the first embodiment.

FIG. 4 is an explanatory diagram illustrating a specific example of intermittent control at the time of starting the compressor according to the first embodiment and changes in the compressor suction pressure due to the specific example.

FIG. 5 is a characteristic diagram that determines whether or not intermittent control is required at the time of compressor startup according to the second embodiment.

FIG. 6 is a characteristic diagram for determining the execution time of the intermittent control when the compressor is started according to the third embodiment.

[Explanation of symbols]

10 ... Compressor, 14 ... Condenser (outdoor heat exchanger), 16 ...
Expansion valve (pressure reducing device for cooling), 18 ... Evaporator (indoor heat exchanger), C ... Refrigeration cycle for cooling, H ... Hot gas heater cycle for heating.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60H 1/22 651 B60H 1/22 651C (72) Inventor Toshitaka Shimizu 1-chome, Showa-cho, Kariya city, Aichi prefecture Stock company DENSO

Claims (7)

[Claims] 1. A refrigerant discharged from a compressor (10),
Cooling in which the indoor heat exchanger (18) is operated as an evaporator by returning to the compressor (10) through the outdoor heat exchanger (14), the cooling decompression device (16) and the indoor heat exchanger (18). Refrigeration cycle for use (C) and refrigerant discharged from the compressor (10) bypasses the outdoor heat exchanger (14), and the indoor heat exchanger (1)
In the refrigeration cycle apparatus configured to be switchable with the heating hot gas heater cycle (H) that operates the indoor heat exchanger (18) as a radiator by returning to the compressor (10) through 8), When the physical quantity related to the suction pressure of the compressor (10) is equal to or less than a predetermined value when the gas heater cycle (H) is started, the compressor (10) is limited in its discharge capacity. A refrigeration cycle apparatus characterized in that 10) is operated for a predetermined time. 2. The refrigeration cycle apparatus according to claim 1, wherein the discharge capacity is limited by interrupting the operation of the compressor (10). 3. The compressor (10) is a variable displacement compressor having a variable capacity mechanism for varying a discharge capacity, and the discharge capacity of the variable displacement compressor (10) is a predetermined capacity smaller than a maximum capacity. The refrigeration cycle apparatus according to claim 1, wherein the discharge capacity is limited by setting the discharge refrigerating capacity. 4. The refrigeration cycle apparatus according to claim 1, wherein the physical quantity related to the suction pressure of the compressor (10) is the outside air temperature. 5. The physical quantity related to the suction pressure of the compressor (10) is an outside air temperature and a rotation speed of the compressor (10), according to any one of claims 1 to 3. Refrigeration cycle equipment. 6. The method according to claim 1, wherein the predetermined time is lengthened according to a decrease in outside air temperature.
Refrigeration cycle device described in. 7. A refrigeration cycle apparatus mounted on a vehicle, wherein the compressor (10) is driven by a vehicle engine (12), and the indoor heat exchanger (18) is for blowing air into a vehicle interior. It is arranged in an air-conditioning case (22) that constitutes a passage, and heats air by using hot water from the vehicle engine (12) as a heat source downstream of the indoor heat exchanger (18) in the air-conditioning case (22). Hot water heat exchanger (24)
The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is arranged.