JPH11101514A - Refrigeration cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle provided with a solenoid capacity control valve having capacity for enough heating performance. SOLUTION: In heating inside a car flowing hot gas discharged from a compressor 7 into an evaporator 7 switching a refrigeration cycle 20 from a refrigerating circuit 21 to a hot gas heater circuit 22, enough auxiliary heating performance is attained by increasing the discharging capacity (Vc) of the compressor 7 when the intake pressure (Ps) of the compressor 7 is first predetermined pressure or less. In heating inside the car flowing the hot gas into the evaporator 6, when the intake pressure (Ps) of the compressor 7 is second predetermined pressure or higher, the protection of refrigeration cycle components and the alleviation of ON/OFF shock are realized by reducing the discharging capacity (Vc) of the compressor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for heating a room, and more particularly, to a high-temperature, high-pressure gas refrigerant discharged from a refrigerant compressor, which is guided to a refrigerant evaporator, and the refrigerant evaporator is provided with a duct inside the duct. The present invention relates to a vehicle air conditioner provided with a refrigeration cycle configured to heat air flowing through a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a vehicle heating device, a cooling water for cooling an engine is guided to a hot water heater in a duct, and the hot water heater heats air flowing in the duct to heat a vehicle interior. Type heating devices are common. However, such a hot water type heating device has a remarkable heating capacity when the engine is started to start the hot water type heating device when the outside air temperature is low and the cooling water temperature is low, that is, when the hot water type heating device starts up. There is a shortage.

[0003] In order to solve the above problems,
For example, in Japanese Patent Application Laid-Open No. 5-223357, a high-temperature, high-pressure gas refrigerant (hot gas) discharged from a compressor of a refrigeration cycle is guided to a refrigerant evaporator through a decompression device and flows through a duct by the refrigerant evaporator. 2. Description of the Related Art A vehicle air conditioner (prior art) including a refrigeration cycle (auxiliary heating device) that assists the heating capacity of a hot water heater by heating air has been proposed. The compressor is an engine-driven compressor that is driven to rotate by an engine via an electromagnetic clutch.

In the heating operation, if the cooling water temperature is equal to or higher than a predetermined temperature, the heating capacity of the hot water heater is sufficiently high by the hot water heater, so that the compressor is turned off to stop the operation of the auxiliary heating device. I have. When the cooling water temperature is lower than a predetermined temperature, the heating capacity of the hot water heater of the hot water heating device is insufficient, so that the compressor is turned on to operate the auxiliary heating device.

[0005] When the discharge pressure discharged from the compressor is higher than a predetermined pressure, the compressor is overloaded, so that the compressor is turned off and the operation of the auxiliary heating device is stopped to protect the refrigeration cycle. ing. When the discharge pressure discharged from the compressor is equal to or lower than a predetermined pressure, the compressor is turned on to operate the auxiliary heating device.

[0006]

However, in the conventional refrigeration cycle, if the heating operation by the hot gas heater circuit is continued for a predetermined time (for example, about 30 minutes), the cooling operation by the normal refrigeration cycle circuit is performed. Both high pressure and low pressure of the refrigeration cycle are higher than at times. For example, the high pressure of the refrigeration cycle is 20 to 25 kg / during a heating operation (operation by a hot gas heater circuit).
cm ² and 13 to 15 kg / cm ² during cooling operation (operation by a refrigeration cycle circuit). The low pressure of the refrigeration cycle is 4 to 5 kg / cm ² during the heating operation.
It is 1-2 kg / cm ² during the cooling operation.

[0007] Further, as described above, the high pressure and the low pressure of the refrigeration cycle are higher during the heating operation performed by the hot gas heater circuit than in the cooling operation performed by the normal refrigeration cycle circuit, and the compressor is operated. O
The torque fluctuation when turning off from the N state is large. For this reason, when the compressor is turned off from the ON state while the vehicle is running, the rotational speed of the engine that drives the compressor by the belt greatly fluctuates, which causes a problem that the power performance and driving performance (drivability) of the vehicle deteriorate. I have.

Therefore, the compressor is frequently turned on and off.
In order to perform capacity control and pressure control without performing F, it is conceivable to change the compressor to a conventionally used variable displacement compressor for a cooler.
However, conventional variable displacement compressors for coolers
The discharge capacity discharged from the compressor decreases as the suction pressure sucked into the compressor decreases.

When such a variable displacement compressor for a cooler is incorporated in a hot gas heater circuit to perform a heating operation, if the heating heat load is large, that is, if the temperature of the suction air sucked into the evaporator is low, the air is removed by the evaporator. The temperature and pressure of the refrigerant that exchanges heat with the temperature decrease. As a result, the discharge capacity discharged from the compressor is reduced by the variable displacement control of the compressor, so the flow rate of the high-temperature refrigerant flowing into the evaporator is also reduced, and the auxiliary heating performance that assists the heating capacity of the hot water heater is sufficiently exhibited. The problem that it does not work arises.

When the heating operation is performed by incorporating the variable displacement compressor for the cooler into the hot gas heater circuit, if the heating heat load is small, that is, if the temperature of the intake air sucked into the evaporator is high, the evaporator uses the air to remove the air. The temperature and pressure of the refrigerant undergoing heat exchange increase. Accordingly, the discharge capacity discharged from the compressor increases due to the variable displacement control of the compressor, and the discharge pressure discharged from the compressor increases.

If the high pressure of the refrigeration cycle becomes higher than an abnormally high pressure (for example, 27 kg / cm ² ), it may lead to failure or breakage of cycle parts such as refrigerant piping. Further, even if the heating heat load is small, as described above, when the high pressure of the refrigeration cycle reaches about 25 kg / cm ² ,
Since the flow rate of the high-temperature refrigerant flowing into the evaporator is also large, there arises a problem that the auxiliary heating capacity for assisting the heating capacity of the hot water heater becomes excessive.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a refrigeration cycle provided with a discharge capacity variable means capable of exhibiting sufficient heating performance. Another object of the present invention is to provide a refrigeration cycle that can prevent failure and breakage of cycle components such as a refrigerant pipe, and can prevent an excessive heating capacity. It is still another object of the present invention to provide a vehicle air conditioner that can obtain an optimum blowing temperature with a minimum necessary power.

[0013]

According to the first aspect of the present invention, a high-temperature, high-pressure refrigerant discharged from a refrigerant compressor flows through a refrigerant evaporator and then returns to the refrigerant compressor. During the operation of the refrigeration cycle, if the suction pressure of the refrigerant compressor is a low pressure equal to or lower than a predetermined value, the discharge capacity of the refrigerant compressor is increased by the operation of the discharge capacity variable means. As a result, even when the heating heat load is large and the suction pressure is a low pressure equal to or less than a predetermined value, the discharge pressure of the refrigerant compressor increases, and the flow rate of the refrigerant flowing into the refrigerant evaporator increases. Therefore, when performing the heating operation using the refrigerant circulation circuit, sufficient heating performance can be exhibited.

According to the second aspect of the present invention, when the suction pressure of the refrigerant compressor is higher than a predetermined value, the discharge capacity of the refrigerant compressor is reduced by the operation of the discharge capacity variable means. Thus, the discharge pressure of the refrigerant compressor can be suppressed, so that even if the operation of the refrigerant compressor is stopped during the operation of the refrigerant compressor, a large torque fluctuation does not occur.
For this reason, even if the start and stop of the refrigerant compressor are repeated, the rotation speed of the internal combustion engine that drives the refrigerant compressor does not fluctuate greatly. Performance degradation can be suppressed. In addition, since the discharge pressure of the refrigerant compressor can be suppressed, failure and breakage of cycle components such as refrigerant piping can be prevented. Since the flow rate of the refrigerant flowing into the refrigerant evaporator also decreases, it is possible to prevent the heating capacity of the refrigerant evaporator from becoming excessive.

According to the third aspect of the present invention, the refrigeration cycle is operated in a refrigerant circuit in which the high-temperature, high-pressure refrigerant discharged from the refrigerant compressor flows to the refrigerant evaporator and then returns to the refrigerant compressor. When the discharge pressure of the refrigerant compressor is higher than or equal to a predetermined value, the discharge capacity of the refrigerant compressor is reduced by the operation of the discharge capacity variable means. Thereby, the same effect as the invention described in claim 2 can be achieved.
According to the fourth aspect of the invention, when the discharge pressure of the refrigerant compressor is a low pressure equal to or lower than a predetermined value, the discharge capacity of the refrigerant compressor is increased by the operation of the discharge capacity variable means. Thereby, the same effect as the first aspect of the invention can be achieved.

According to the fifth aspect of the present invention, when the suction pressure of the refrigerant compressor is lower than a predetermined value when the first refrigerant circuit is switched to the first refrigerant circuit, the operation of the discharge displacement variable means is performed. The discharge capacity of the refrigerant compressor is reduced. As a result, the discharge pressure of the refrigerant compressor decreases, and the flow rate of the refrigerant flowing into the refrigerant evaporator also decreases. For this reason, even if the operation of the refrigerant compressor is not stopped, it is possible to prevent the cooling capacity of the refrigerant evaporator from becoming excessive and to prevent the refrigerant evaporator from being frosted. In addition, when the suction pressure of the refrigerant compressor is higher than a predetermined value when switching to the second refrigerant circuit, the discharge capacity of the refrigerant compressor is reduced by the action of the discharge capacity variable means. Thereby, the same effect as that of the invention described in claim 2 can be achieved.

According to the sixth aspect of the invention, when the suction pressure of the refrigerant compressor is lower than a predetermined value when the mode is switched to the second refrigerant circulation circuit, the operation of the discharge displacement variable means is performed. The discharge capacity of the refrigerant compressor increases. Thereby, the same effect as the first aspect of the invention can be achieved.

According to the seventh aspect of the invention, when the discharge pressure of the refrigerant compressor is higher than the set value, the discharge capacity of the refrigerant compressor is reduced by the operation of the discharge capacity variable means. Thereby, the same effect as the invention described in claim 2 can be achieved. In addition, by setting the set value of the discharge pressure of the refrigerant compressor lower as the blow-out temperature detected by the blow-out temperature detecting means approaches the target value, the temperature of the cooling water which was low immediately after the internal combustion engine was started is set. , The discharge capacity of the refrigerant compressor can be reduced. Thereby, the rotational power of the internal combustion engine that rotationally drives the refrigerant compressor can be minimized. Furthermore, since the flow rate of the refrigerant flowing into the refrigerant evaporator is reduced, the air is heated when passing through the refrigerant evaporator, and the outlet temperature of the air that is reheated when passing through the hot water heater becomes the optimum outlet temperature, Excessive heating capacity of the refrigerant evaporator can be prevented.

According to the present invention, the set value of the discharge pressure of the refrigerant compressor decreases as the air temperature immediately after passing through the hot water heater detected by the heater outlet temperature detecting means approaches the target value. By setting, the same effects as those of the invention described in claim 7 can be achieved. According to the ninth aspect of the present invention, the set value of the discharge pressure of the refrigerant compressor is set lower as the temperature of the coolant flowing into the hot water heater detected by the coolant temperature detector approaches the target value. By doing so, it is possible to achieve the same effect as the invention described in claim 7.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

[Configuration of First Embodiment] FIGS. 1 to 7 show a first embodiment of the present invention.
FIG. 1 shows an embodiment, and FIG. 1 is a diagram showing an entire structure of a vehicle air conditioner.

The air conditioner for a vehicle according to the present embodiment is an air conditioner unit (air conditioner unit) 1 for air conditioning the interior of a vehicle equipped with an engine (internal combustion engine) E as a main heat source for heating.
Is an air conditioner for a vehicle configured to control each air conditioner (actuator) in the above by an air conditioning controller (hereinafter, referred to as an air conditioner ECU) 10.

The air conditioning unit 1 is provided with an air conditioning duct 2 forming an air passage 11 for guiding conditioned air into the vehicle interior. An outside air intake port, an inside air intake port, and an inside / outside air switching door (all not shown) are provided at the most upstream side of the air conditioning duct 2, and a centrifugal blower 3 is provided downstream of the air supply port. ing. Further, on the most downstream side of the air conditioning duct 2, there are provided outlets such as a defroster outlet, a face outlet or a foot outlet, and a mode switching door (not shown).

The centrifugal blower 3 is composed of a scroll casing integrally provided in the air conditioning duct 2, a blower motor 12 controlled by a blower driving circuit (not shown), and a centrifugal fan 13 driven to rotate by the blower motor 12. It is configured. In addition, the air flow rate of the centrifugal fan 13 of the present embodiment is configured to be continuously or stepwise switched from 0 stage (OFF) to 32 stages.

Next, a hot water heater 5 of a hot water type heating device (main heating device) 4 for reheating the air passing through an evaporator 6, which will be described later, is provided upstream of the air outlet. The hot water heater 5 is installed in a cooling water circulation circuit 14 in which a cooling water circulation flow is generated by a water pump (not shown) driven by the engine E.
When the hot water valve 15 installed in the cooling water circulation circuit 14 opens, the hot water heater 5 recirculates the cooling water that has absorbed the exhaust heat of the engine E, and reheats the air using the cooling water as a heating heat source. That is, a downstream heat exchanger (second heat exchanger) that performs an air heating action. here,
These engine E, hot water heater 5, cooling water circulation circuit 1
4 and the hot water valve 15 constitute the hot water heating device 4.

Next, between the centrifugal blower 3 and the hot water heater 5, the evaporator 6, which is a component of the refrigeration cycle 20 mounted on the vehicle, closes the entire air passage 11 in the air conditioning duct 2. It is arranged in. The refrigeration cycle 20 includes a first refrigerant circulation circuit (hereinafter, referred to as a refrigeration cycle circuit) 21, a second refrigerant circulation circuit (hereinafter, referred to as a hot gas heater circuit) 22, a refrigeration cycle circuit 21, and a hot gas heater circuit 22. First and second solenoid valves 23 and 24 for switching are provided.

The refrigeration cycle circuit 21 includes a compressor 7
The high temperature, high pressure gas refrigerant discharged from the first solenoid valve 2
3 → condenser (refrigerant condenser) 25 → receiver (gas-liquid separator) 26 → expansion valve (first decompression means) 27 → evaporator 6 → accumulator (gas-liquid separator) 28 is there. The hot gas heater circuit 22 also supplies the high-temperature, high-pressure gas refrigerant (hot gas) discharged from the compressor 7 to the second solenoid valve 24 → a pressure reducing device (second pressure reducing means) 29 → the evaporator 6 → the accumulator 28 and the compressor 7. The refrigerant circuit circulates in the order of

In the refrigeration cycle 20, when the first solenoid valve 23 opens and the second solenoid valve 24 closes, the refrigerant flows back into the refrigeration cycle circuit 21. In addition, the refrigeration cycle 20
When the first solenoid valve 23 closes and the second solenoid valve 24 opens, the refrigerant flows back into the hot gas heater circuit 22. The first and second solenoid valves 23 and 24 constitute a circulation circuit switching unit of the present invention. A cooling fan 16 is rotationally driven by a drive motor 17 and forcibly blows outside air to the condenser 25.

The evaporator 6 corresponds to the refrigerant evaporator of the present invention. When the refrigerant flows through the refrigeration cycle circuit 21, the low-temperature gas-liquid two-phase refrigerant flowing from the expansion valve 27 evaporates and passes through the air. Works as a cooling heat exchanger. Further, the evaporator 6 heats the air passing therethrough by flowing the high-temperature gas refrigerant flowing from the pressure reducing device 29 when the refrigerant flows in the hot gas heater circuit 22.
It works as a heat exchanger for heating (auxiliary heating device, hot gas heater of auxiliary heat source system). Here, the expansion valve 27
In addition to adiabatic expansion of the refrigerant, the refrigerant circulation amount is adjusted according to the degree of superheat of the refrigerant at the outlet of the evaporator 6.

Next, the compressor 7 of this embodiment is shown in FIG.
A brief description will be given with reference to FIG. Here, FIG. 2 is a view showing a compressor 7 of a variable discharge capacity type integrated with an electromagnetic clutch. The compressor 7 is connected to an electromagnetic clutch 8 that transmits and shuts off the power of the engine E to the compressor 7.

In the electromagnetic clutch 8, a stator housing 32 fixed to a housing 44 of the compressor 7 via an annular mounting flange 31 and a pulley 33 connected to the engine E via a belt V are joined to the outer periphery. A rotor 34 facing the rotor 34 with a small gap therebetween, and an armature 35 having a friction surface frictionally engaging the friction surface of the rotor 34; The electromagnetic coil 37 causes the rotor 34 to be attracted to the rotor 34 against the elastic force of the rubber hub (elastic body) 36, and the armature 35 and the shaft 40 of the compressor 7 via the outer hub 38 and the rubber hub 36.
And an inner hub 39 connecting the two.

The compressor 7 is equivalent to a refrigerant compressor of the present invention, and is a well-known waffle-type compressor whose discharge capacity can be changed. The shaft 7 rotates integrally with the inner hub 39 of the electromagnetic clutch 8. 40, a swash plate 41 obliquely fixed to the shaft 40, and a swash plate 4
1, a housing (front housing) 44 for connecting a cylinder (rear housing) 43 on which the piston 42 slides, and a housing 44 connected to the rear end of the housing 44 to reduce the displacement of the compressor 7. And an electromagnetic displacement control valve (corresponding to a discharge displacement varying means of the present invention) 9 for making the displacement variable.

Here, a cylinder chamber 45 is formed between the cylinder 43 and the piston 42. A suction port (not shown) formed by a suction valve (not shown) formed of an elastic metal plate is formed near the center of the valve plate 46 forming the cylinder chamber 45.
This suction port is connected to the valve body 47 of the electromagnetic displacement control valve 9.
Is connected to a suction port 48 formed at Further, a discharge port 50 which is opened and closed by a discharge valve 49 formed of an elastic metal plate is formed near the outside of the valve plate 46. The discharge port 50 communicates with a discharge port 51 formed in the valve body 47. In the housing 44, a fixed throttle 53a for effectively communicating the crank chamber 52 for allowing the swash plate 41 to be displaceable and the suction port 48 and the discharge port 51 are provided.
53b (see FIG. 3) is provided.

As described above, when the electromagnetic coil 37 of the electromagnetic clutch 8 is in the energized state (ON), the armature 35 of the electromagnetic clutch 8 is attracted to the rotor 34 and the rotor 34 and the armature 35 are frictionally engaged. E
Is transmitted to the shaft 40 of the compressor 7 via the belt V and the electromagnetic clutch 8. Thereby, the evaporator 6 is activated by the activation of the refrigeration cycle 20.
An air cooling action or an air heating action is performed. When the power supply to the electromagnetic coil 37 of the electromagnetic clutch 8 is stopped (OFF), the armature 3 of the electromagnetic clutch 8 is turned off.
5 is separated from the rotor 34 and the rotor 34 and the armature 35
Is interrupted. As a result, the power of the engine E is not transmitted to the shaft 40 of the compressor 7, and the air cooling action or the air heating action by the evaporator 6 is stopped.

Next, the electromagnetic displacement control valve 9 will be described with reference to FIGS. Here, FIG.
FIG. 2 is a view showing a schematic structure of an electromagnetic displacement control valve 9 incorporated in the apparatus.

A refrigerant pressure circuit is formed in the body of the compressor 7 and the valve body 47 of the electromagnetic displacement control valve 9. The refrigerant pressure circuit includes pressure passages 54 to 56 through which the suction pressure (Ps) of the compressor 7 is led, and pressure passages 57 and 5 through which the discharge pressure (Pd) of the compressor 7 is led.
8, a pressure passage 59 for providing a crank chamber pressure (Pc) to the crank chamber 52 of the compressor 7, a communication port 61 communicating with the communication passage 60, and a communication passage 6 communicating with the pressure passage 59.
And 2. The communication passage 60 communicates the junction 61 downstream of the pressure passage 55 and downstream of the pressure passage 58 with the communication port 61. Further, the communication passage 62 communicates the junction of the downstream side of the pressure passage 56 and the junction of the downstream side of the pressure passage 57 with the pressure passage 59.

The opening of the communication port 61 is determined by the stop position of the valve body 63. The stop position of the valve body 63 is configured to be determined by the displacement positions of the plunger 64 and the bellows 65. Plunger 64
The bellows 65 is connected to the valve body 63 via rods 67 and 68. The set position of the plunger 64 is configured to be changed according to the magnitude of the control current to the electromagnetic coil 69. Reference numeral 70 denotes a return spring for returning the plunger 64 to the initial position.

The opening and closing of the pressure passages 57 and 58 are determined by the stop position of the valve body 71. The opening and closing of the pressure passages 55 and 56 are determined by the stop position of the valve body 72 that is interlocked with the valve body 71. Those valve bodies 71, 7
The stop position 2 is configured to be changed according to the magnitude of the control current to the electromagnetic coil 73. Reference numeral 74 denotes a return spring for returning the valve bodies 71 and 72 to the initial positions.

Therefore, the electromagnetic displacement control valve 9 controls the compressor 7 by the control current from the air conditioner ECU 10.
Is a discharge capacity varying means for varying the discharge capacity of the compressor 7 by changing the set value of the suction pressure (Ps). That is, the electromagnetic displacement control valve 9 is connected to the valve body 4.
The external force applied to the plunger 64 and the bellows 65 is varied by applying a control current to the electromagnetic coil 69 in the inside 7. By varying the relationship between the suction pressure (Ps) and the opening degree of the valve body 63, the actual force is varied. Control is performed so that the post-evaporation temperature (TE) becomes the target post-evaporation temperature (TEO).

Next, the air conditioner ECU 10 will be described with reference to FIGS. Here, FIG. 4 is a diagram showing a control system of the vehicle air conditioner.

Each switch signal from each switch on an air conditioner operation panel (not shown) provided in the front of the vehicle compartment is input to an air conditioner ECU (heating control means) 10 for controlling each air conditioning means in the air conditioning unit 1. Is done. In addition,
On the air-conditioner operation panel, there are a mode changeover switch 100 for switching the air-conditioning mode between a cooler mode (cooling operation) and a heater mode (heating operation), and a temperature setting switch (temperature) for setting the temperature in the passenger compartment to a desired temperature. A setting unit 101, an air conditioner switch 102 for instructing start or stop of the refrigeration cycle 20, and a blower switch 103 for instructing on / off of the centrifugal blower 3 are provided.

In the air conditioner ECU 10, C
A well-known microcomputer including a PU, a ROM, a RAM, and the like is provided, and each sensor signal from each sensor is A / D converted by an input circuit (not shown), and then input to the microcomputer. When an ignition switch (key switch) for starting and stopping the engine E of the vehicle is turned on (IG / ON), the air conditioner ECU 10 receives a signal from a battery (not shown) which is a vehicle-mounted power supply mounted on the vehicle. The control processing is started when DC power is supplied.

The air conditioner ECU 10 has an inside air temperature sensor (inside air temperature detecting means) 104 for detecting the air temperature in the vehicle compartment (hereinafter referred to as the inside air temperature), and an air temperature outside the vehicle compartment (hereinafter the outside air temperature). An outside air temperature sensor (outside air temperature detecting means) 105 for detecting, an insolation sensor (insolation amount detecting means) 106 for detecting an amount of solar radiation entering the vehicle interior,
A post-evaporation temperature sensor (post-evaporation temperature detection means) 107 for detecting the air temperature (hereinafter referred to as “after-evaporation temperature”) immediately after passing through the evaporator 6, and a cooling water temperature sensor for detecting the temperature of the cooling water flowing into the hot water heater 5 (Cooling water temperature detection means)
108 and the high pressure of the refrigeration cycle 20 (discharge pressure: P
Refrigerant pressure sensor (high pressure detection means) 1 for detecting d)
09 is input. The above-mentioned switches and sensors detect air-conditioning environmental factors necessary for air-conditioning the cabin of the automobile.

[Control Method of First Embodiment] Next, compressor capacity control by the air conditioner ECU 10 of the present embodiment will be briefly described with reference to FIGS. here,
FIG. 5 is a flowchart showing a method of controlling the discharge capacity by the air conditioner ECU 10.

When the ignition switch is turned on (IG / O
N) and when DC power is supplied to the air conditioner ECU 10, the routine of FIG. 5 is started. First, each switch signal is read from each switch on the air conditioner operation panel (step S1). Next, each sensor signal is read (step S2). Specifically, the inside air temperature (TR) detected by the inside air temperature sensor 104, the outside air temperature (TAM) detected by the outside air temperature sensor 105, the amount of solar radiation (TS) detected by the solar radiation sensor 106, the temperature sensor after evaporation The post-evaporation temperature (TE) detected at 107, the cooling water temperature (TW) detected by the cooling water temperature sensor 108, and the discharge pressure (Pd) of the compressor 7 detected by the refrigerant pressure sensor 109
Read.

Next, the following equation 1 previously stored in the ROM
The target blowing temperature (TAO) of the air blown into the vehicle compartment is calculated based on the formula (Step S3).

## EQU1 ## TAO = Kset × Tset−KR × TR−K
AM × TAM-KS × TS + C

Note that Tset is a temperature setting switch 101
And TR is the inside air temperature sensor 10
TAM is the outside air temperature sensor 1
At the outside air temperature detected at 05, TS is the solar radiation sensor 106
Is the amount of solar radiation detected at. Also, Kset, KR, K
AM and KS are gains, and C is a correction constant.

Next, it is determined whether the air conditioning mode is the cooler mode. Specifically, target outlet temperature (TAO)
Is lower than or equal to a predetermined temperature or whether the mode changeover switch 100 is set to the cooler mode (step S4). If the determination result is YES, the electromagnetic clutch 8 is energized (ON), and the first electromagnetic valve 2 is turned on.
3 is opened, the second solenoid valve 24 is closed, and the refrigeration cycle 20 is operated by the refrigeration cycle circuit 21 (Step S).
5).

Next, the electromagnetic coil 7 of the electromagnetic capacity control valve 9
3 is energized (ON) (step S6). Thereafter, the process proceeds to step S9. Therefore, as shown in the figure of step S6, the suction pressure (Ps) of the compressor 7
Is reduced, the displacement control (Vc) of the compressor 7 is reduced, and the displacement control (Vc) of the compressor 7 is increased when the suction pressure (Ps) of the compressor 7 is increased.

If the result of the determination in step S4 is NO, the electromagnetic clutch 8 is energized (ON), the first electromagnetic valve 23 is closed, the second electromagnetic valve 24 is opened, and the hot gas heater The refrigeration cycle 20 is operated by the circuit 22 (step S7). Next, the electromagnetic coil 7 of the electromagnetic capacity control valve 9
The energization of No. 3 is stopped (OFF) (step S8). Therefore, as shown in the drawing of step S8, when the suction pressure (Ps) of the compressor 7 decreases, the discharge capacity (Vc) of the compressor 7 increases, and when the suction pressure (Ps) of the compressor 7 increases, the pressure of the compressor 7 increases. Capacity control for reducing the ejection capacity (Vc) is executed.

Next, the cooling heat load or the heating heat load is determined based on the target outlet temperature (TAO), and the target post-evaporation temperature (TEO) is determined from the cooling heat load or the heating heat load. Specifically, the target post-evaporation temperature (TEO) is calculated so as to increase as the target outlet temperature (TAO) increases (step S9). Next, capacity control of the compressor 7 is performed so that the actual post-evaporation temperature (TE) detected by the post-evaporation temperature sensor 107 becomes equal to the target post-evaporation temperature (TEO) (step S10). Specifically, the control current to the electromagnetic coil 69 of the electromagnetic capacity control valve 9 is controlled.
Thereafter, the process exits the routine of FIG.

[Operation of First Embodiment] Next, the operation of the vehicle air conditioner of this embodiment will be briefly described with reference to FIGS. Here, FIG. 6 is a view showing an operation state of the electromagnetic capacity control valve in the cooler mode, and FIG. 7 is a view showing an operation state of the electromagnetic capacity control valve in the heater mode.

When the actual post-evaporation temperature (TE) is considerably higher than the target post-evaporation temperature (TEO), the control current flowing through the electromagnetic coil 69 of the electromagnetic displacement control valve 9 is reduced to draw the compressor 7 Decrease the set value of pressure (Ps). In this case, when the bellows 65 contracts, the valve body 63 is displaced small and the opening of the communication port 61 is reduced. As a result, the discharge pressure (P
d) hardly enters the pressure passage 59, and the crank chamber pressure (Pc) decreases. Then, the crank chamber pressure (P
c) is reduced, the swash plate 41 of the compressor is reduced.
Increases, the stroke of the piston 42 becomes longer. As a result, the discharge pressure (Pd) of the compressor 7 increases, so that the discharge capacity (Vc) of the compressor 7 increases.

When the actual post-evaporation temperature (TE) is substantially equal to the target post-evaporation temperature (TEO), the control current flowing through the electromagnetic coil 69 of the electromagnetic displacement control valve 9 is increased to draw the compressor 7 Increase the set value of pressure (Ps). In this case, when the bellows 65 expands, the valve body 63 is largely displaced, and the opening of the communication port 61 is increased. Thereby, the discharge pressure (Pd) of the compressor 7
Enters the pressure passage 59 and the crank chamber pressure (Pc) increases. Then, as the crank chamber pressure (Pc) increases, the inclination of the swash plate 41 of the compressor decreases, and the stroke of the piston 42 decreases. As a result, the discharge pressure (Pd) of the compressor 7 decreases, so that the discharge capacity (Vc) of the compressor 7 decreases.

When the air conditioning mode is the cooler mode, the electromagnetic clutch 8 is turned on, the first electromagnetic valve 23 opens, and the second electromagnetic valve 24 closes. Therefore, the high-temperature, high-pressure gas refrigerant discharged from the compressor 7 flows back into the evaporator 6 through the refrigeration cycle circuit 21. The air sucked into the air-conditioning duct 2 exchanges heat with a low-temperature, low-pressure refrigerant in the evaporator 6 to be cooled and blown out into the vehicle interior. Thereby, the vehicle interior is cooled.

When the air conditioning mode is the cooler mode, the electromagnetic coil 73 of the electromagnetic capacity control valve 9 is energized (O
N), the valve bodies 71 and 72 are displaced downward in the drawing against the reaction force of the return spring 74 as shown in FIG. 6, so that the pressure passage 56 and the communication passage 62 communicate with each other, The pressure passage 58 and the communication passage 60 communicate with each other. For this reason, the discharge pressure (Pd) is guided to the valve body 63, and the lower the suction pressure (Ps) of the compressor 7 becomes, the lower the valve body 63 is displaced to the valve-opening side and the communication port 61 is opened. Degree, the pressure in the crank chamber of the compressor 7 (Pc)
Will be higher.

Thus, the suction pressure (Ps) is set to the first predetermined pressure (for example, a gauge pressure of 2 kg / cm ² ).
At the time of the following low pressure, the valve body 63 opens, and the crank chamber pressure (Pc) rises due to the discharge pressure (Pd),
The discharge capacity (Vc) of the compressor 7 is controlled to 5% capacity. Further, when the suction pressure (Ps) is higher than a second predetermined pressure (for example, a gauge pressure of 2.1 kg / cm ² ), the valve body 63 is fully closed and the crank chamber pressure (P
c) becomes equal to the suction pressure (Ps) and the compressor 7
Discharge capacity (Vc) is controlled to 100% capacity.

When the suction pressure (Ps) is higher than the first predetermined pressure and lower than the second predetermined pressure, the valve body 63
Is displaced toward the valve closing side, the crank chamber pressure (Pc) becomes higher than the suction pressure (Ps), and approaches the discharge pressure (Pd), so that the discharge capacity (Vc) of the compressor 7 is varied (FIG. 5). Step S6).

When the air conditioning mode is the heater mode, the electromagnetic clutch 8 is turned on, the first electromagnetic valve 23 is closed, and the second electromagnetic valve 24 is opened. Further, the hot water valve 15 is also opened. Therefore, the high-temperature, high-pressure gas refrigerant discharged from the compressor 7 flows back into the evaporator 6 through the hot gas heater circuit 22. The cooling water that has absorbed the exhaust heat of the engine E flows back into the cooling water circulation circuit 14 and flows into the hot water heater 5. The air sucked into the air-conditioning duct 2 is heated by exchanging heat with a high-temperature, low-pressure refrigerant in the evaporator 6, and further heated by exchanging heat with high-temperature cooling water in the hot water heater 5 to enter the vehicle interior. Be blown out. Thereby, the vehicle interior is heated.

Since the energization of the electromagnetic coil 73 of the electromagnetic capacity control valve 9 is stopped (OFF), as shown in FIG.
When the valve bodies 71 and 72 are displaced upward in the figure by the reaction force of the return spring 74, the pressure passage 55 and the communication passage 60 communicate with each other, and the pressure passage 57 and the communication passage 62 communicate with each other. For this reason, the suction pressure (Ps) is guided to the valve body 63. Therefore, the lower the suction pressure (Ps) of the compressor 7 is, the more the valve body 63 is displaced to the valve opening side and the opening degree of the communication port 61 is increased. And the pressure (Pc) in the crank chamber of the compressor 7 decreases.

Thus, the suction pressure (Ps) is set to the first predetermined pressure (for example, a gauge pressure of 3 kg / cm ² ).
At the time of the following low pressure, the valve body 63 is fully opened, the crank chamber pressure (Pc) becomes equal to the suction pressure (Ps), and the discharge capacity (Vc) of the compressor 7 is controlled to 100% capacity. Further, when the suction pressure (Ps) is a high pressure equal to or lower than a second predetermined pressure (for example, a gauge pressure of 3.1 kg / cm ² ), the valve body 63 closes and the crank chamber pressure (P
c) is increased by the discharge pressure (Pd), and the discharge capacity (Vc) of the compressor 7 is controlled to 5% capacity.

Further, when the suction pressure (Ps) is higher than the first predetermined pressure and lower than the second predetermined pressure, the valve body 63
Is displaced toward the valve closing side, the crank chamber pressure (Pc) becomes higher than the suction pressure (Ps), and approaches the discharge pressure (Pd), so that the discharge capacity (Vc) of the compressor 7 is varied (FIG. 5). Step S8).

[Effects of the First Embodiment] As described above, the air conditioner for a vehicle controls the discharge capacity of the compressor 7 in accordance with the cooling heat load and the heating heat load without turning the electromagnetic clutch 8 on and off. By adjusting with the type capacity control valve 9, the air cooling performance (cooling performance) of the evaporator 6, the air heating performance (auxiliary heating performance) of the evaporator 6, and the discharge pressure (Pd) of the compressor 7 can be controlled to optimal values. As a result, the compressor 7 does not repeatedly turn on and off frequently, so that the compressor 7 does not greatly fluctuate in torque. For this reason, since the rotation speed of the engine E that drives the compressor 7 by the belt does not fluctuate greatly, power performance such as acceleration performance and climbing performance and driving performance of the vehicle do not deteriorate.

When the air conditioning mode is the cooler mode, by using the electromagnetic displacement control valve 9 of the present embodiment, the cooling heat load is reduced and the suction pressure (Ps) of the compressor 7 is reduced.
Decreases, the discharge capacity (Vc) of the compressor 7 decreases. Therefore, since the cooling performance of the evaporator 6 is reduced, it is possible to suppress the occurrence of excessive cooling capacity and the occurrence of frost on the evaporator 6.

When the heating heat load is large when the air-conditioning mode is the heater mode, for example, when the hot water type heating apparatus 4 starts up in a low temperature environment where the outside air temperature is equal to or lower than a predetermined temperature (for example, 0 ° C.) (starting of the engine E) If the low-temperature air is sucked into the evaporator 6 at the time, the evaporator 6 exchanges heat with the low-temperature air, thereby lowering the temperature and pressure of the refrigerant. As a result, the suction pressure (Ps) of the compressor 7 decreases. However, by using the electromagnetic displacement control valve 9 of the present embodiment, the discharge displacement (Vc) of the compressor 7 increases even if the suction pressure (Ps) of the compressor 7 decreases. Therefore, the flow rate of the refrigerant circulating in the hot gas heater circuit 22 increases, so that the flow rate of the refrigerant flowing into the evaporator 6 increases.
Therefore, sufficient auxiliary heating performance can be exhibited even when the heating heat load is large.

When the air conditioning mode is the heater mode, by using the electromagnetic displacement control valve 9 of the present embodiment, the heating heat load is reduced and the suction pressure (Ps) of the compressor 7 is reduced.
Increases, the discharge capacity (Vc) of the compressor 7 decreases. Therefore, the auxiliary heating performance of the evaporator 6 decreases, and the discharge pressure (P
d) becomes lower. Thereby, it is possible to prevent the auxiliary air heating capacity from becoming excessive due to the inside air temperature exceeding the set temperature, and to prevent failure and damage of cycle components (refrigeration equipment) such as refrigerant piping used in the refrigeration cycle 20.

[Second Embodiment] FIG. 8 shows a second embodiment of the present invention and is a view schematically showing the structure of an electromagnetic displacement control valve incorporated in a compressor.

The electromagnetic displacement control valve 9 of the present embodiment has a first
In a simplified version of the embodiment, fixed throttles 53a, 53b are arranged in the communication passages 62a, 62b of the refrigerant pressure circuit,
A fixed throttle 53c is disposed in the pressure passage 55. And
When the air conditioning mode is the cooler mode, the electromagnetic coil 73 is energized (ON) in the electromagnetic capacity control valve 9. Therefore, as shown in FIG. 8, the valve body 71 is displaced downward in the figure against the reaction force of the return spring 74,
The pressure passage 58 and the communication passage 60 communicate with each other.

Thus, when the suction pressure (Ps) is higher than the second predetermined pressure set in advance, the valve body 63 is displaced closest to the valve closing side, and the crank chamber pressure (Pc) becomes higher than the suction pressure (Ps). ), And the discharge capacity (Vc) of the compressor 7 is controlled to 100% capacity. When the suction pressure (Ps) is higher than the first predetermined pressure and lower than the second predetermined pressure, the valve body 63 is displaced to the valve opening side and the crank chamber pressure (Pc) becomes higher than the suction pressure (Pc). Ps) and approaches the discharge pressure (Pd). This allows
The lower the suction pressure (Ps), the more the compressor 7
Is changed so that the discharge capacity (Vc) becomes smaller.

When the air-conditioning mode is the heater mode, the energization of the electromagnetic coil 73 of the electromagnetic capacity control valve 9 is stopped (OFF). Therefore, the return spring 7
When the valve body 71 is displaced upward in the drawing by the reaction force of No. 4, the pressure passage 57 and the communication passage 62a communicate with each other. Thus, when the suction pressure (Ps) is a low pressure equal to or lower than the first predetermined pressure, the valve body 63 is fully opened, and the crank chamber pressure (Pc) becomes equal to the suction pressure (Ps). The discharge capacity (Vc) is controlled to 100% capacity. When the suction pressure (Ps) is higher than the first predetermined pressure and lower than the second predetermined pressure, the valve body 63 is displaced to the valve closing side, and the crank chamber pressure (Pc) becomes higher than the suction pressure (Pc).
s) and approaches the discharge pressure (Pd). Thus, the discharge capacity (Vc) of the compressor 7 is varied so as to decrease as the suction pressure (Ps) increases.

[Third Embodiment] FIG. 9 shows a third embodiment of the present invention and is a view schematically showing the structure of an electromagnetic displacement control valve incorporated in a compressor.

In the electromagnetic displacement control valve 9 of this embodiment, the communication port 61 and the pressure passage 58 are directly connected by the communication passage 60, and the pressure passage 59 and the pressure passage 55 are connected by the communication passages 62a and 62a.
When the air conditioning mode is the heater mode, the discharge capacity (Vc) is controlled to 100% fixed capacity by communicating with the communication passage 2b and disposing the solenoid valve 75 in the communication passage 62a.

In the cooler mode, the solenoid valve 75
By stopping the power supply (OFF) and closing the valve, a refrigerant pressure circuit similar to that in the cooler mode of the first embodiment is obtained. In the heater mode, the solenoid valve 75 is energized (O
N) to open the valve, the crank chamber pressure (Pc) is always controlled in the same manner as the suction pressure (Ps), and the discharge capacity (Vc) is set to 100 regardless of the level of the suction pressure (Ps).
It is configured to be fixed at% capacity.

[Configuration of Fourth Embodiment] FIGS. 10 and 1
1 shows a fourth embodiment of the present invention, and FIG. 10 is a view showing a schematic structure of an electromagnetic displacement control valve built in a compressor.

The electromagnetic displacement control valve 9 of the present embodiment protects cycle parts such as refrigerant piping when the discharge pressure (Pd) of the compressor 7 is high, and sets the compressor 7 from ON to OFF.
A high-pressure control valve 80 that varies the discharge capacity (Vc) of the compressor 7 is provided in parallel with a view to suppressing fluctuations in the rotation speed of the engine E when the FF is performed.

The refrigerant pressure circuit of the high-pressure control valve 80 includes a pressure passage 81 for leading the suction pressure (Ps) of the compressor 7, pressure passages 82 and 83 for leading the discharge pressure (Pd) of the compressor 7, and A pressure passage 84 for providing the crank chamber pressure (Pc) to the crank chamber 52 and a communication port 85 communicating the pressure passages 83 and 84 are provided. Note that a fixed throttle 81a is provided in the pressure passage 81. The opening of the communication port 85 is determined by the stop position of the valve 86. The stop position of the valve body 86 is determined by the displacement positions of the rod 87 and the bellows 88. Reference numeral 89 denotes a return spring for returning the bellows 88 to the initial position.

[Control Method of Fourth Embodiment] Next, compressor capacity control by the air conditioner ECU 10 of the present embodiment will be briefly described with reference to FIGS. 10 and 11. Here, FIG. 11 is a flowchart showing a method of controlling the displacement by the air conditioner ECU 10.

After performing the processing of step S10 in the flowchart of FIG. 5 of the first embodiment, the discharge capacity (Vc) is controlled using the high-pressure control valve 80 (step S11).
Thus, when the discharge pressure (Pd) applied to the pressure passage 82 rises above the preset operating pressure of the bellows 88, the valve body 86 opens to open the communication port 85, and the crank chamber pressure (Pc) Will be higher.

Accordingly, the discharge pressure (Pd) of the compressor 7 becomes equal to the first predetermined pressure (for example, a gauge pressure of 20 kg / c).
When the pressure is lower than m ² ), the discharge capacity (Vc) of the compressor 7 is controlled to be 100% capacity. In addition, the discharge pressure (Pd) of the compressor 7 is higher than the first predetermined pressure, and the second predetermined pressure (for example, a gauge pressure of 22 kg /
When the discharge pressure (Pd) is lower than the predetermined value (cm ² ), the discharge capacity (Vc) is variably controlled so as to decrease as the discharge pressure (Pd) increases. When the discharge pressure (Pd) of the compressor 7 is equal to or higher than the second predetermined pressure, the discharge capacity (Vc) of the compressor 7 is controlled to be, for example, 5%.

[Fifth Embodiment] FIGS. 12 and 13 show a fifth embodiment of the present invention. FIG. 12 shows an electromagnetic displacement control valve, a switching control valve and a hot gas displacement control built in a compressor. It is a figure showing the schematic structure of the valve.

The electromagnetic displacement control valve 9 of this embodiment is a variable displacement control means in the cooler mode. The electromagnetic capacity control valve 9 includes a return spring 91 for returning the plunger 64 to the initial position, a spring seat 92 of the return spring 91, and an adjusting plug 93 for adjusting the displacement of the plunger 64. Is provided. Also, a return spring 94 for returning the bellows 65 to the initial position is provided inside the bellows 65.

A stopper 96 for setting the initial load of the return spring 94 is provided at the end of the valve body 95 of the electromagnetic displacement control valve 9. The valve body 95 has a pressure passage 95 c for applying a pressure (Pc) to the crank chamber 52 of the compressor 7.
Pressure passage 95 for guiding discharge pressure (Pd) of compressor 7
d and a pressure passage 95s for guiding the suction pressure (Ps) of the compressor 7 are formed.

The refrigerant pressure circuit communicating with the electromagnetic displacement control valve 9 includes a switching control valve 98 for changing the stop position of the valve body 97 between the cooler mode and the heater mode, and a variable control valve in the heater mode. A hot gas capacity control valve 99 as capacity control means is provided. The switching control valve 98 includes a valve body 97, an electromagnetic coil 97a, and a return spring 97.
b. The switching control valve 98 has a communication passage 98a communicating with the pressure passage 95d, a communication passage 98b communicating with the hot gas capacity control valve 99, and a pressure passage 98d for guiding the discharge pressure (Pd) of the compressor 7. Have been.

The hot gas volume control valve 99 has a valve body 99a and a bellows 99b. And
The hot gas capacity control valve 99 is formed with a pressure passage 99 c for applying a crank chamber pressure (Pc) to the crank chamber 52 of the compressor 7. The pressure passage 99c is
It communicates with the discharge port 51 via the crank chamber 52. Reference numeral 99e denotes a return spring for returning the valve body 99a and the bellows 99b to their initial positions.

In the present embodiment, when the air conditioning mode is the cooler mode, the energization of the electromagnetic coil 97a of the switching control valve 98 is stopped (OFF), and the valve body 97 is displaced upward in the figure by the reaction force of the return spring 97b. The communication passage 98b is closed. As a result, the pressure passage 95 of the electromagnetic displacement control valve 9
The discharge pressure (Pd) of the compressor 7 is led to d.

Then, the suction pressure (Ps) given to the pressure passage 95 s becomes equal to the second predetermined pressure (for example, a gauge pressure of 2.1 k).
g / cm ² ) or more, as shown in FIG. 13A, the bellows 65 contracts and the valve body 63 closes, so that the crank chamber pressure (Pc) increases the suction pressure (Pc). Ps) and the displacement of the compressor 7 (V
c) becomes 100% capacity. Further, when the suction pressure (Ps) is a low pressure equal to or lower than a first predetermined pressure (for example, a gauge pressure of 2 kg / cm ² ), as shown in FIG. By opening the valve, the pressure in the crank chamber (Pc) becomes equal to the discharge pressure (Pd), and the discharge capacity (Vc) of the compressor 7 becomes 5% capacity. When the suction pressure (Ps) is higher than the first predetermined pressure and lower than the second predetermined pressure, as shown in FIG. 13A, the discharge capacity (Vc) of the compressor 7 becomes equal to the suction pressure (Vc). The higher the value of Ps), the more continuously it can be varied from 5% capacity to 100% capacity.

When the air conditioning mode is the heater mode, the electromagnetic coil 97a of the switching control valve 98 is energized (ON).
Then, the valve body 97 is displaced downward in the figure to close the communication passage 98a. Thereby, the discharge pressure (Pd) of the compressor 7 is guided into the control chamber 99d of the hot gas capacity control valve 99. Then, the discharge pressure (P
d) is the first predetermined pressure (for example, a gauge pressure of 20 kg / c)
In the case of a low pressure of m ² ) or less, as shown in FIG. 13B, the bellows 99b expands and the valve body 99a closes, so that the crank chamber pressure (Pc) increases the suction pressure (Pc).
s) and the displacement of the compressor 7 (Vc)
Becomes 100% capacity.

The discharge pressure (Pd) given to the control chamber 99d is equal to the second predetermined pressure (for example, a gauge pressure of 22 kg / g).
In the case of a high pressure of not less than ² cm ² ), as shown in FIG. 13B, the bellows 99b contracts and the valve body 99a opens, so that the crank chamber pressure (Pc) is increased to the discharge pressure (Pd). And the discharge capacity of compressor 7 (V
c) is 5% capacity. The suction pressure (Ps) is the first
When the pressure is higher than the predetermined pressure and lower than the second predetermined pressure, as shown in FIG. 13B, the discharge capacity (Vc) of the compressor 7 increases as the discharge pressure (Pd) increases. It is continuously varied from 100% capacity to 5% capacity.

[Structure of Sixth Embodiment] FIGS. 14 to 1
7 shows a sixth embodiment of the present invention, FIG. 14 is a view showing the overall structure of a vehicle air conditioner, and FIG. 15 is an electromagnetic displacement control valve, a switching control valve and a high pressure FIG. 16 is a diagram showing a schematic structure of a control valve, and FIG. 16 is a diagram showing a control system of a vehicle air conditioner.

In the cooler mode and the heater mode, the electromagnetic displacement control valve 9 of this embodiment controls the discharge pressure (Pd) of the compressor 7 by the control current from the air conditioner ECU 10 as shown in FIG. The variable displacement control means varies the discharge displacement (Vc) of the compressor 7 by changing the set value. In this embodiment, an electromagnetic high-pressure control valve 120 is provided instead of the hot gas volume control valve 99 of the fifth embodiment.

The high-pressure control valve 120 is connected to the valve body 1
19 has a valve body 122 for changing the opening of a communication port 121, and a heater outlet temperature (TH) detected by a heater outlet temperature sensor 110 described later is a predetermined target heater outlet temperature (THO). (For example, 50 ° C.), the discharge pressure variable means for setting the set value of the discharge pressure (Pd) of the compressor 7 to be lower as it approaches.

The stop position of the valve body 122 is
3 and the position of the bellows 124 are determined. That is, the plunger 123 and the bellows 124 are connected to the intermediate member 125 and the rod 12
6 and connected to the valve body 122. The setting position of the plunger 123 is configured to be changed according to the magnitude of the control current to the electromagnetic coil 127.

A return spring 128 for returning the plunger 123 to the initial position is provided in the valve body 119. A return spring 129 for returning the bellows 124 to the initial position is provided inside the bellows 124. A stopper 130 for setting an initial load of the return spring 129 is provided at an end of the valve body 119.

The valve body 119 has a crank chamber pressure (Pc) in the crank chamber 52 of the compressor 7.
A pressure passage 131 for guiding the discharge pressure (Pd) of the compressor 7 through the communication passage 98b;
133 are formed. The pressure passage 131 and the pressure passage 132 communicate with each other through a communication port 121 in the valve body 119. Accordingly, the high-pressure control valve 120 has a structure in which the discharge pressure (Pd) of the compressor 7 is sent to the crank chamber (control pressure chamber) 52.
27 is determined by the balance of the force of the plunger 123 in accordance with the control current to 27.

On the other hand, an air conditioner ECU 10 for controlling air conditioning means in the air conditioning unit 1, for example, an electromagnetic clutch 8, an electromagnetic displacement control valve 9, a blower motor 12, a drive motor 17, a switching control valve 98, a high pressure control valve 120, and the like.
, A switch signal is input from various switches such as a mode changeover switch 100, a temperature control lever 111, an air conditioner switch 102, and a blower switch 103. Of these, the temperature control lever 111 is
When operated to the most side, maximum cooling operation (MAX CO
OL), and when operated to the farthest side, a maximum heating operation (MAX HOT) is commanded.

The air conditioner ECU 10 includes an inside air temperature sensor 104, an outside air temperature sensor 105, a solar radiation sensor 10
6. Post-evaporation temperature sensor 107, cooling water temperature sensor 10
8. Sensor signals are input from various sensors such as the refrigerant pressure sensor 109 and the heater outlet temperature sensor 110.
Among them, the heater outlet temperature sensor 110 corresponds to an outlet temperature detecting unit of the present invention, and is a heater outlet temperature detecting unit for detecting an air temperature immediately after passing through the hot water heater 5 (hereinafter referred to as a heater outlet temperature). is there.

[Control Method of Sixth Embodiment] Next, compressor capacity control by the air conditioner ECU 10 of this embodiment will be briefly described with reference to FIGS.

After performing the processing of step S10 in the flowchart of FIG. 5 of the first embodiment, the discharge capacity (Vc) of the compressor 7 is controlled by, for example, feedback control (PI control). More specifically, the compressor controls the target value of the control current supplied to the electromagnetic coil 97a of the switching control valve 98 and the energization stop, and the control current supplied to the electromagnetic coil 69 of the electromagnetic displacement control valve 9 and the electromagnetic coil 127 of the high-pressure control valve 120. 7 is calculated (determined) (control current calculation means).

Specifically, the control current (In) is calculated based on the following equations (2) and (3).

## EQU2 ## En = TH-THO

In = In-1−Kp ｛(En−En−1) + (θ)
/ Ti) × En｝

Note that TH is a heater outlet temperature sensor 110
In the actual heater blowout temperature detected in the above, THO is a preset target heater blowout temperature (for example, 50 ° C.) and Kp
Is the proportionality constant and θ is the sampling time (for example, 1 second)
Where Ti is the integration time, En is the current temperature deviation, and En is
-1 is the previous temperature deviation, In is the current control current, In
-1 is the previous control current.

Here, when the occupant operates the ignition switch to start the engine E to start the hot water type heating device 4, the cooling water that has cooled the engine E through the cooling water circulation circuit 14 is supplied to the hot water heater in the air conditioning duct 2. Flow into 5.
Then, the temperature control lever 111 is set to MAX / HO.
It is set at the T position, the outside air temperature (TAM) is lower than a predetermined temperature (for example, −5 ° C.), and the heater blowing temperature (T
If H) is lower than the target heater outlet temperature (THO), the engine E is started until a predetermined time (for example, 5 minutes to 15 minutes) elapses (at startup).
The cooling water temperature is low, and the heating capacity of the hot water heater 5 is insufficient.

Therefore, the first solenoid valve 23 is closed, the second solenoid valve 24 is opened, the refrigeration cycle 20 is switched from the refrigeration cycle circuit 21 to the hot gas heater circuit 22, the electromagnetic clutch 8 is turned on, and the compressor is turned on. 7 is activated to assist the heating capacity of the hot water type heating device 4. At this time, since the air conditioning mode is the heater mode, the electromagnetic coil 97a of the switching control valve 98 is energized (ON) and the valve body 9 is turned on.
7 is displaced downward in the figure, and the communication passage 98a is closed. Thereby, the pressure passages 132 and 133 are formed via the communication passage 98b.
The discharge pressure (Pd) of the compressor is guided to the inside.

The discharge pressure (Pd) applied to the pressure passage 133 is equal to the first predetermined pressure (for example, the gauge pressure 20 k
g / cm ² ) or less, as shown in FIG. 17B, the bellows 124 expands and the valve body 122 closes, so that the crank chamber pressure (Pc) increases the suction pressure (Pc). Ps), and the discharge capacity (Vc) of the compressor 7 increases to 100% capacity.

The discharge pressure (Pd) applied to the pressure passage 133 is equal to the second predetermined pressure (for example, a gauge pressure of 22 kg).
/ Cm ² ) or more, as shown in FIG. 17B, the bellows 124 contracts and the valve body 122 opens, so that the crank chamber pressure (Pc) increases the discharge pressure (Pd). ), The discharge capacity of the compressor 7 (V
c) is reduced to 5% capacity.

When the suction pressure (Ps) applied to the pressure passage 133 is higher than the first predetermined pressure and lower than the second predetermined pressure, as shown in FIG.
The discharge capacity (Vc) of the compressor 7 is the discharge pressure (Pd)
The higher the is, the more continuously variable from 100% capacity to 5% capacity.

Here, the electromagnetic coil 1 of the high-pressure control valve 120
27 is changed based on the above equation (2) and the equation (3).
As the heater outlet temperature (TH) detected at 10 approaches the target heater outlet temperature (THO: for example, 50 ° C.), the discharge pressure (Pd) of the compressor 7 as shown by the arrow in FIG. Is set low.

As a result, the temperature of the cooling water, which was low immediately after the start of the engine E, rises and the heating heat load decreases, and even if the discharge pressure (Pd) of the compressor 7 decreases, the discharge of the compressor 7 decreases. The capacitance (Vc) can be further reduced. Thereby, the heater outlet temperature (T
When H) approaches the target heater outlet temperature (THO), the rotational power of the engine E that belt-drives the compressor 7 via the electromagnetic clutch 8 becomes a necessary minimum. In addition, the flow rate of the refrigerant flowing into the evaporator 6 decreases. At this time, the air flowing in the air conditioning duct 2 is supplied to the evaporator 6.
Is heated slightly when passing through the hot water heater 5, and is sufficiently heated when passing through the hot water heater 5, so that the air blowing temperature becomes the optimum blowing temperature and the heating capacity of the evaporator 6 can be prevented from becoming excessive.

[Other Embodiments] In the present embodiment, the present invention is applied to a refrigeration cycle of an air conditioner for a vehicle such as an automobile, but the present invention is applied to a refrigeration cycle of an air conditioner for an aircraft, a ship or a railroad vehicle. You may. Further, the present invention may be applied to a refrigeration cycle of an air conditioner of a factory, a store, a house, or the like.

In the sixth embodiment, the heater outlet temperature sensor 110 is used as the outlet temperature detecting means, but the cooling water temperature sensor 108 may be used as the outlet temperature detecting means.
That is, the cooling water temperature (TW) is equal to the target cooling water temperature (TW).
O: For example, 80 ° C.), the set value of the discharge pressure (Pd) of the compressor 7 may be set to be lower as it approaches.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an overall structure of a vehicle air conditioner (first embodiment).

FIG. 2 is a sectional view showing an electromagnetic clutch and a compressor of a variable discharge capacity type (first embodiment).

FIG. 3 is an explanatory view showing a schematic structure of an electromagnetic displacement control valve (first embodiment).

FIG. 4 is a block diagram showing a control system of the vehicle air conditioner (first embodiment).

FIG. 5 is a flowchart showing a discharge capacity control method by the air conditioner ECU (first embodiment).

FIG. 6 is an explanatory diagram showing an operation state of an electromagnetic displacement control valve in a cooler mode (first embodiment).

FIG. 7 is an explanatory diagram showing an operation state of an electromagnetic displacement control valve in a heater mode (first embodiment).

FIG. 8 is an explanatory view showing a schematic structure of an electromagnetic displacement control valve (second embodiment).

FIG. 9 is an explanatory diagram showing a schematic structure of an electromagnetic displacement control valve (third embodiment).

FIG. 10 is an explanatory view showing a schematic structure of an electromagnetic displacement control valve (fourth embodiment).

FIG. 11 is a flowchart showing a discharge capacity control method by an air conditioner ECU (fourth embodiment).

FIG. 12 is an explanatory diagram showing a schematic structure of an electromagnetic displacement control valve, a switching control valve, and a hot gas displacement control valve (fifth embodiment);
Embodiment).

13A is a graph showing a relationship between a suction pressure and a discharge capacity of a compressor, and FIG. 13B is a graph showing a relationship between a discharge pressure and a discharge capacity of a compressor (fifth embodiment).
Embodiment).

FIG. 14 is a configuration diagram showing an overall structure of a vehicle air conditioner (sixth embodiment).

FIG. 15 is an explanatory diagram showing a schematic structure of an electromagnetic displacement control valve, a switching control valve, and a high-pressure control valve (sixth embodiment).

FIG. 16 is a block diagram showing a control system of the vehicle air conditioner (sixth embodiment).

17A is a graph showing a relationship between a set value of a discharge pressure of a compressor and a control current, and FIG. 17B is a graph showing a relationship between a discharge pressure of the compressor and a discharge capacity (Sixth Embodiment). Embodiment).

[Explanation of symbols]

E engine (internal combustion engine) 1 air conditioning unit 2 air conditioning duct 3 centrifugal blower 4 hot water heating device 5 hot water heater 6 evaporator (refrigerant evaporator) 7 compressor (refrigerant compressor) 8 electromagnetic clutch 9 electromagnetic displacement control valve (discharge capacity) Variable means) 10 air conditioner ECU 14 cooling water circulation circuit 20 refrigeration cycle 21 refrigeration cycle circuit (first refrigerant circulation circuit) 22 hot gas heater circuit (refrigerant circulation circuit, second refrigerant circulation circuit) 23 first solenoid valve (circulation circuit switching means) 24 Second solenoid valve (circulation circuit switching means) 25 Condenser (refrigerant condenser) 98 Switching control valve 99 Hot gas capacity control valve 110 Heater outlet temperature sensor (Air outlet temperature detecting means, Heater outlet temperature detecting means) 120 High pressure control valve ( Discharge pressure variable means)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hajime Ito 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside

Claims (9)

[Claims] (A) a refrigerant compressor which is driven to rotate by an internal combustion engine to compress a refrigerant; (b) a refrigerant evaporator which exchanges heat of an inflowing refrigerant with air to evaporate the refrigerant; and (c) the refrigerant. (D) a refrigerant circulation circuit for flowing the refrigerant discharged from the compressor to the refrigerant evaporator and returning the refrigerant to the refrigerant compressor; and (d) when the suction pressure sucked into the refrigerant compressor becomes lower than a predetermined value. A refrigerating cycle comprising: a discharge capacity variable unit configured to increase a discharge capacity discharged from the refrigerant compressor. 2. The refrigeration cycle according to claim 1, wherein the discharge capacity variable means is configured to discharge the discharge capacity from the refrigerant compressor when a suction pressure sucked into the refrigerant compressor becomes higher than a predetermined value. A refrigeration cycle characterized by reducing the size of the refrigeration cycle. (A) a refrigerant compressor which is driven to rotate by an internal combustion engine and compresses a refrigerant; (b) a refrigerant evaporator which exchanges heat of the inflowing refrigerant with air to evaporate the refrigerant; and (c) the refrigerant. (D) a refrigerant circulation circuit for flowing the refrigerant discharged from the compressor to the refrigerant evaporator and returning the refrigerant to the refrigerant compressor; and (d) when the discharge pressure discharged from the refrigerant compressor becomes higher than a predetermined value. A refrigerating cycle comprising: a discharge capacity variable unit configured to reduce a discharge capacity discharged from the refrigerant compressor. 4. The refrigeration cycle according to claim 3, wherein the discharge capacity variable means is configured to discharge the discharge capacity from the refrigerant compressor when the discharge pressure discharged from the refrigerant compressor falls below a predetermined value. A refrigeration cycle characterized by having a larger size. 5. A refrigerant compressor which is driven to rotate by an internal combustion engine to compress refrigerant, (b) a refrigerant condenser which exchanges heat of the inflowing refrigerant with a cooling medium to condense and liquefy, and (c) inflowing A refrigerant evaporator for exchanging heat with the air to evaporate the refrigerant, and (d) flowing the refrigerant discharged from the refrigerant compressor through the refrigerant condenser to the refrigerant evaporator, And (e) the refrigerant discharged from the refrigerant compressor is bypassed from the refrigerant condenser, flows to the refrigerant evaporator, and returns to the refrigerant compressor. A second refrigerant circuit, (f) a circuit switching means for switching between the first refrigerant circuit and the second refrigerant circuit, and (g) the refrigerant when being switched to the first refrigerant circuit. The suction pressure sucked into the compressor is When the pressure is lower than the predetermined value, the discharge capacity discharged from the refrigerant compressor is reduced, and the suction pressure sucked into the refrigerant compressor is increased to a predetermined value or more when the refrigerant refrigerant is switched to the second refrigerant circuit. A refrigeration cycle comprising discharge capacity variable means for reducing the discharge capacity discharged from the refrigerant compressor. 6. The refrigeration cycle according to claim 5, wherein the discharge capacity variable means is configured to increase a suction pressure sucked into the refrigerant compressor to a predetermined value or more when the first refrigerant circuit is switched. When the suction pressure increases, the discharge capacity discharged from the refrigerant compressor increases, and when the suction pressure sucked into the refrigerant compressor decreases to a predetermined value or less when being switched to the second refrigerant circulation circuit, A refrigeration cycle characterized by increasing a discharge capacity discharged from a refrigerant compressor. (A) an air-conditioning duct for introducing conditioned air into the vehicle interior; (b) a refrigerant evaporator arranged in the air-conditioning duct to exchange heat with the air flowing in the refrigerant and evaporate the refrigerant; c) a hot water heater arranged downstream of the refrigerant evaporator in the air conditioning duct and heating the air using cooling water of the internal combustion engine as a heating heat source; and (d) rotating the internal combustion engine to drive the refrigerant. A refrigerant compressor for compressing; (e) a refrigerant circuit for flowing refrigerant discharged from the refrigerant compressor to the refrigerant evaporator and returning the refrigerant to the refrigerant compressor; and (f) flowing out of the internal combustion engine. Cooling water flowing through the hot water heater and returning the cooled water to the internal combustion engine; (g) when the discharge pressure discharged from the refrigerant compressor becomes higher than a set value, the refrigerant compressor Discharge volume to be discharged (H) a blow-out temperature detecting means for detecting a blow-out temperature of air blown out from the air conditioning duct into the vehicle interior; and (i) a blow-out temperature detected by the blow-out temperature detecting means to a target value. An air conditioner for a vehicle, comprising: a discharge pressure variable unit that sets a set value of the discharge pressure to be lower as approaching. 8. A vehicle air conditioner according to claim 7, wherein said blow-out temperature detecting means is a heater blow-out temperature detecting means for detecting an air temperature immediately after passing through said hot water heater. Air conditioner. 9. A vehicle air conditioner according to claim 7, wherein said outlet temperature detecting means is a cooling water temperature detecting means for detecting a temperature of cooling water flowing into said hot water heater. Air conditioner.