JP2012250708A - Vehicle air conditioning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit the deterioration in durability of a cycle composition apparatus constituting a refrigeration cycle applied to a vehicle air conditioning apparatus.SOLUTION: The apparatus includes refrigerant circuit switching devices 13-24 of the refrigerant cycle 10 that is applied to the vehicle air conditioning apparatus 1 and is configured to switch a refrigerant circuit for circulating a refrigerant. After a compressor 11 is stopped and when a high-pressure-side refrigerant pressure Pd on a discharge side of the compressor 11 is equal to or lower than a predetermined reference high-pressure-side refrigerant pressure f (Tamdisp), the refrigerant circuit switching devices 13-24 switch the refrigerant circuit.

Description

  The present invention relates to a vehicle air conditioner including a refrigeration cycle.

  2. Description of the Related Art Conventionally, there is known a vehicle air conditioner that performs temperature adjustment and humidity adjustment of blown air blown into a vehicle interior by a vapor compression refrigeration cycle.

  For example, Patent Document 1 discloses an outdoor heat exchanger that exchanges heat between refrigerant and outdoor air, an indoor heat exchanger that exchanges heat between refrigerant and blown air, and refrigerant circuit switching means that switches a refrigerant circuit through which the refrigerant circulates. A vehicle air conditioner including a refrigeration cycle having a plurality of electromagnetic valves is disclosed.

  In the vehicle air conditioner disclosed in Patent Document 1, the amount of heat absorbed by the indoor heat exchanger is dissipated by the outdoor heat exchanger by changing the operation state of the plurality of solenoid valves and switching the refrigerant circuit, and the blown air A plurality of operation modes such as a cooling mode for cooling the air and a heating mode for heating the blown air by dissipating the amount of heat absorbed by the outdoor heat exchanger by the indoor heat exchanger are realized.

Japanese Patent Laid-Open No. 9-286225

  By the way, as represented by the switching of the operation mode in the vehicle air conditioner disclosed in Patent Document 1, in recent years, there has been a demand for multi-functionality of the vehicle air-conditioning apparatus. Complicated control for the components of the refrigeration cycle or addition of new components to the refrigeration cycle is being performed.

  Therefore, when the multi-functionality of the vehicle air conditioner is performed, it becomes a problem to deteriorate the durability of the cycle component device driven in a complicated control mode or to ensure the durability of the newly added cycle component device. .

  For example, the refrigeration cycle applied to the vehicle air conditioner of Patent Document 1 has a plurality of solenoid valves as refrigerant circuit switching means for switching refrigerant circuits. When switching to a cooling mode refrigerant circuit that is most frequently used among the plurality of operation modes and in which the temperature in the engine room in which the plurality of solenoid valves are mounted is likely to rise, one solenoid valve is energized. is doing.

  Thus, energizing the solenoid valve during the frequently used operation mode causes an increase in power consumption of the entire vehicle air conditioner. Furthermore, energizing the solenoid valve in a state where the ambient temperature is high causes an abnormal increase in the temperature of the coil constituting the solenoid valve, which adversely affects the durability of the solenoid valve.

  In view of the above points, an object of the present invention is to suppress a deterioration in durability of cycle constituent devices constituting the refrigeration cycle in a vehicle air conditioner including the refrigeration cycle.

  Another object of the present invention is to suppress deterioration in the durability of the refrigerant circuit switching means in a vehicle air conditioner including a refrigeration cycle having refrigerant circuit switching means for switching refrigerant circuits.

  In order to achieve the above object, according to the first aspect of the present invention, a compressor (11) for sucking in refrigerant, compressing and discharging the refrigerant, an outdoor heat exchanger (16) for exchanging heat between the refrigerant and outdoor air, and It has a vapor compression refrigeration cycle (10) having indoor heat exchangers (12, 26) for exchanging heat between the refrigerant and the blown air blown into the passenger compartment, and the refrigeration cycle (10) includes an indoor heat exchanger ( The heat quantity absorbed in 26) is dissipated in the outdoor heat exchanger to cool the blown air, and the heat quantity absorbed in the outdoor heat exchanger (16) is transferred to the indoor heat exchanger (12). The refrigerant circuit switching means (13-24) for switching the refrigerant circuit in the heating mode that heats the blown air by dissipating heat is provided. The refrigerant circuit switching means (13-24) is provided after the compressor (11) is stopped. Compressor (11) discharge side high pressure side cooling When the pressure (Pd) becomes a predetermined reference high-pressure side refrigerant pressure (f (Tamdisp)) or less, and wherein the air conditioning system switches the refrigerant circuit.

  Here, when the solenoid valve is employed as the refrigerant circuit switching means (13 to 24), when the solenoid valve is opened and closed when the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the solenoid valve is large, the solenoid valve valve Since the load due to the refrigerant pressure acting on the body increases, the load applied to the solenoid valve increases compared to when the pressure difference is small. Moreover, when the load which acts on the valve body of a solenoid valve becomes large, the operation sound of a solenoid valve will also become loud.

  On the other hand, according to the present invention, the refrigerant circuit switching means (13 to 24) is after the compressor (11) is stopped, and the high pressure side refrigerant pressure (Pd) on the discharge side of the compressor (11) is Since the refrigerant circuit is switched when the pressure becomes lower than a predetermined reference high-pressure side refrigerant pressure (f (Tamdisp)), the pressure difference between the inlet-side refrigerant pressure and the outlet-side refrigerant pressure of the refrigerant circuit switching means (13 to 24). Then, the refrigerant circuit switching means (13 to 24) can be operated.

  Therefore, it is possible to prevent an unnecessary load from being applied to the refrigerant circuit switching means (13 to 24), and to suppress deterioration in durability of the refrigerant circuit switching means (13 to 24). As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

  Furthermore, after the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the refrigerant circuit switching means (13 to 24) becomes small, the refrigerant circuit switching means (13 to 24) is operated to operate the refrigerant circuit switching means. The operating sound of (13-24) becomes small. Therefore, the switching can be performed without giving a sense of incongruity to the occupant when switching the refrigerant circuit.

According to a second aspect of the present invention, in the vehicle air conditioner according to the first aspect, the reference high-pressure side refrigerant pressure (f (Tamdisp)) is determined to become a lower value as the outside air temperature decreases. It is characterized by being.
In the refrigeration cycle (10), when the operation of the compressor (11) is stopped, the low-pressure refrigerant pressure on the suction side of the compressor (11) is approximately saturated depending on the outside air temperature. Therefore, the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the refrigerant circuit switching means (13 to 24) is the saturation pressure according to the outside air temperature and the high pressure side refrigerant pressure (Pd) on the discharge side of the compressor (11). And the difference.

  Accordingly, the reference high-pressure side refrigerant pressure (f (Tamdisp)) is determined to become a low value as the outside air temperature decreases, whereby the inlet-side refrigerant pressure and the outlet-side refrigerant of the refrigerant circuit switching means (13 to 24). It is possible to quickly determine that the pressure difference from the pressure has decreased, and to suppress the deterioration of the durability of the refrigerant circuit switching means (13 to 24), and to operate the refrigerant circuit switching means (13 to 24). Sound can be reduced.

  According to a third aspect of the present invention, in the vehicle air conditioner according to the first or second aspect of the present invention, the vehicular air conditioner further includes a blower outlet mode switching unit that switches a wind direction of the blown air blown into the passenger compartment. 13 to 24), when the air outlet mode switching means switches the air outlet mode to a mode in which blown air is blown out toward the window in the vehicle interior, the high pressure side refrigerant pressure (Pd) is the reference high pressure side refrigerant pressure. The refrigerant circuit is switched even at a pressure higher than (f (Tamdisp)).

  According to this, when it takes time for the high-pressure side refrigerant pressure (Pd) to drop to the reference high-pressure side refrigerant pressure (f (Tamdisp)) due to the outside air temperature, the temperature condition in the engine room, etc., the operation noise is reduced. Priority can be given to the anti-fogging of the window glass in the passenger compartment. That is, priority can be given to safety during vehicle travel.

  According to a fourth aspect of the present invention, in the vehicle air conditioner according to any one of the first to third aspects, the refrigerant circuit switching means (13 to 24) is predetermined from the time when the compressor (11) is stopped. When the reference stop time has elapsed, the refrigerant circuit is switched even if the high-pressure side refrigerant pressure (Pd) is higher than the reference high-pressure side refrigerant pressure (f (Tamdisp)).

  According to this, when it takes time for the high-pressure side refrigerant pressure (Pd) to drop to the reference high-pressure side refrigerant pressure (f (Tamdisp)) due to the outside air temperature, the temperature condition in the engine room, etc., the operation noise is reduced. In particular, priority can be given to suppression of deterioration of air conditioning feeling such as a feeling of heating or cooling of the occupant.

  Moreover, in invention of Claim 5, in the vehicle air conditioner as described in any one of Claim 1 thru | or 4, a refrigerant circuit switching means (13-24) is after a stop of a compressor (11). When a predetermined reference pressure drop time has elapsed since the compressor (11) stopped, the high-pressure side refrigerant is compared with the high-pressure side refrigerant pressure (Pd) and the reference high-pressure side refrigerant pressure (f (Tamdisp)). The refrigerant circuit is switched when the pressure (Pd) becomes equal to or lower than the reference high-pressure side refrigerant pressure (f (Tamdisp)).

  According to this, the refrigerant circuit switching means (13 to 24) determines the high-pressure side refrigerant pressure (Pd) according to claim 1 after a predetermined reference pressure drop time has elapsed since the compressor (11) was stopped. Since the refrigerant circuit is switched by performing the operation, the refrigerant circuit switching unit (13-24) is operated after the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the refrigerant circuit switching unit (13-24) becomes small. be able to.

Therefore, the operation and effect of the invention according to claim 1, that is, the refrigerant circuit switching means (13 to 24) can be more reliably prevented from being subjected to unnecessary loads, and the refrigerant circuit switching means (13 to 24) can be prevented. Deterioration of durability can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle. Furthermore, the operation sound of the refrigerant circuit switching means (13 to 24) can be reduced, and the refrigerant circuit can be switched without giving a sense of discomfort to the occupant when the refrigerant circuit is switched.
According to a sixth aspect of the present invention, in the vehicle air conditioner according to the fifth aspect, the refrigerant circuit switching means (13 to 24) is configured to start before the reference pressure drop time elapses at the time of starting to start the air conditioning in the passenger compartment. Even so, the refrigerant circuit is switched.

  Since the refrigerant pressure in the refrigeration cycle is equalized at the time of starting to start air conditioning in the passenger compartment, the refrigerant circuit switching means (13 to 24) can be switched even if the refrigerant circuit is switched without waiting for the elapse of the reference time. There is little adverse effect on durability, and the operating noise is low. Therefore, as in the present invention, the air conditioning feeling such as a feeling of heating or cooling of the occupant can be improved by switching the refrigerant circuit even before the reference pressure drop time elapses.

  According to a seventh aspect of the present invention, in the vehicle air conditioner according to any one of the first to sixth aspects, the refrigerant circuit switching means includes a plurality of electromagnetic valves (13 to 13) that operate when supplied with electric power. 24), and the plurality of solenoid valves (13 to 24) are configured from solenoid valves (13 to 24) having a small pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure after the compressor (11) is stopped. It operates in order and switches the refrigerant circuit.

  According to this, after a stop of a compressor (11), a plurality of solenoid valves (13-24) in order from a solenoid valve (13-24) with a small pressure difference with the inlet side refrigerant pressure and outlet side refrigerant pressure. Since the refrigerant circuit is switched by operating, first, it is possible to prevent an unnecessary load from being applied to the solenoid valve (13 to 24) having the smallest pressure difference, and to suppress deterioration of its durability. At the same time, the operating noise is reduced.

  Further, by operating the solenoid valves (13 to 24) having the smallest pressure difference, the refrigerant pressure in the cycle can be equalized. The pressure difference of the solenoid valves (13 to 24) having a small pressure difference can be reduced. Therefore, it is possible to prevent unnecessary load from being applied to the electromagnetic valves (13 to 24) to be operated next, thereby suppressing deterioration of the durability and reducing the operating noise.

That is, the deterioration of durability of the plurality of solenoid valves (13 to 24) constituting the refrigerant circuit switching means can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle. Furthermore, the operation sound of the refrigerant circuit switching means (13 to 24) can be reduced, and the refrigerant circuit can be switched without giving a sense of discomfort to the occupant when the refrigerant circuit is switched.
In addition, the code | symbol in the parenthesis of each means described in this column and the claim shows an example of a correspondence relationship with the specific means described in the embodiment described later.

It is a whole block diagram which shows the refrigerant circuit at the time of the air conditioning mode of the vehicle air conditioner of 1st Embodiment. It is a whole block diagram which shows the refrigerant circuit at the time of the heating mode of the vehicle air conditioner of 1st Embodiment. It is a whole block diagram which shows the refrigerant circuit at the time of the 1st dehumidification mode of the vehicle air conditioner of 1st Embodiment. It is a whole block diagram which shows the refrigerant circuit at the time of the 2nd dehumidification mode of the vehicle air conditioner of 1st Embodiment. It is a block diagram which shows the electric control part of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows control of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows another principal part of control of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows another principal part of control of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows another principal part of control of the vehicle air conditioner of 1st Embodiment. It is a time chart corresponding to control of FIG. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 2nd Embodiment. It is a time chart corresponding to the control of FIG. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 3rd Embodiment. It is a time chart corresponding to the control of FIG. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 4th Embodiment. It is a time chart corresponding to the control of FIG. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 5th Embodiment. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 6th Embodiment. It is a flowchart which shows the principal part of control of the vehicle air conditioner of 7th Embodiment. It is a flowchart which shows a part of principal part of control of the vehicle air conditioner of 8th Embodiment. It is a flowchart which shows the continuation of FIG. It is a flowchart which shows a part of principal part of control of the vehicle air conditioner of 9th Embodiment. It is a flowchart which shows a part of principal part of control of the vehicle air conditioner of 10th Embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the vehicle air conditioner of the present invention is applied to a so-called hybrid vehicle that obtains a driving force for vehicle travel from an internal combustion engine (engine) EG and a travel electric motor. 1 to 4 are overall configuration diagrams of the vehicle air conditioner 1.

  The vehicle air conditioner includes a cooling mode (COOL cycle) for cooling the passenger compartment, a heating mode (HOT cycle) for heating the passenger compartment, a first dehumidifying mode (DRY_EVA cycle) for dehumidifying the passenger compartment and a second dehumidifying mode ( (DRY_ALL cycle) is provided with a vapor compression refrigeration cycle 10 configured to be able to switch a refrigerant circuit. 1-4 respectively show the flow of the refrigerant in the cooling mode, the heating mode, and the first and second dehumidification modes by solid arrows.

  The first dehumidification mode is a dehumidification mode that prioritizes the dehumidification capacity over the heating capacity, and the second dehumidification mode is a dehumidification mode that prioritizes the heating capacity over the dehumidification capacity. Therefore, the first dehumidification mode can be expressed as a low temperature dehumidification mode or a simple dehumidification mode, and the second dehumidification mode can be expressed as a high temperature dehumidification mode or a dehumidification heating mode.

  The refrigeration cycle 10 includes a compressor 11, an indoor condenser 12 and an indoor evaporator 26 as indoor heat exchangers, a temperature expansion valve 27 and a fixed throttle 14 as decompression means for decompressing and expanding the refrigerant, and a refrigerant circuit switching means. As a plurality (5 in this embodiment) of electromagnetic valves 13, 17, 20, 21, 24, and the like.

  Further, the refrigeration cycle 10 employs a normal chlorofluorocarbon refrigerant as the refrigerant, and constitutes a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. Furthermore, this refrigerant is mixed with refrigerating machine oil for lubricating the compressor 11, and this refrigerating machine oil circulates in the cycle together with the refrigerant.

  The compressor 11 is disposed in the engine room, sucks the refrigerant in the refrigeration cycle 10, compresses it, and discharges it. The electric motor 11b drives the fixed capacity compression mechanism 11a having a fixed discharge capacity. It is configured as a compressor. Specifically, various types of compression mechanisms such as a scroll type compression mechanism and a vane type compression mechanism can be adopted as the fixed capacity type compression mechanism 11a.

  The electric motor 11b is an AC motor whose operation (number of rotations) is controlled by the AC voltage output from the inverter 61. Further, the inverter 61 outputs an AC voltage having a frequency corresponding to a control signal output from the air conditioning control device 50 described later. And the refrigerant | coolant discharge capability of the compressor 11 is changed by this rotation speed control. Therefore, the electric motor 11b constitutes a discharge capacity changing unit of the compressor 11.

  The refrigerant inlet side of the indoor condenser 12 is connected to the discharge side of the compressor 11. The indoor condenser 12 is disposed in a casing 31 that forms an air passage for the blown air that is blown into the vehicle interior in the indoor air conditioning unit 30 of the vehicle air conditioner, and a refrigerant that circulates in the casing 31 and an indoor evaporator described later. It is a heat exchanger for heating which heats blowing air by heat-exchanging with blowing air after passing 26. The details of the indoor air conditioning unit 30 will be described later.

  An electric three-way valve 13 is connected to the refrigerant outlet side of the indoor condenser 12. The electric three-way valve 13 is refrigerant circuit switching means whose operation is controlled by a control voltage output from the air conditioning control device 50.

  More specifically, the electric three-way valve 13 switches to a refrigerant circuit that connects between the refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet side of the fixed throttle 14 in an energized state in which electric power is supplied. In the non-energized state in which the supply of the refrigerant is stopped, the refrigerant circuit is switched to a refrigerant circuit that connects between the refrigerant outlet side of the indoor condenser 12 and one refrigerant inlet / outlet of the first three-way joint 15.

  The fixed throttle 14 is a dehumidifying means for heating and dehumidifying that decompresses and expands the refrigerant flowing out of the electric three-way valve 13 in the heating mode and the first and second dehumidifying modes. As the fixed throttle 14, a capillary tube, an orifice, or the like can be employed. Of course, an electric variable throttle mechanism in which the throttle passage area is adjusted by a control signal output from the air-conditioning control device 50 may be employed as the decompression means for heating and dehumidification. A refrigerant inlet / outlet port of a third three-way joint 23 described later is connected to the refrigerant outlet side of the fixed throttle 14.

  The first three-way joint 15 has three refrigerant inflow / outflow ports and functions as a branching portion that branches the refrigerant flow path. Such a three-way joint may be constituted by joining refrigerant pipes, or may be constituted by providing a plurality of refrigerant passages in a metal block or a resin block. In addition, one refrigerant inlet / outlet of the outdoor heat exchanger 16 is connected to another refrigerant inlet / outlet of the first three-way joint 15, and the refrigerant inlet side of the low-pressure solenoid valve 17 is connected to another refrigerant inlet / outlet. ing.

  The low pressure solenoid valve 17 has a valve body portion that opens and closes the refrigerant flow path and a solenoid (coil) that drives the valve body portion, and the operation of which is controlled by a control voltage output from the air conditioning control device 50. Circuit switching means. More specifically, the low-pressure solenoid valve 17 is configured as a so-called normally closed on-off valve that opens in an energized state and closes in a non-energized state.

  One refrigerant inlet / outlet port of a fifth three-way joint 28 described later is connected to the refrigerant outlet side of the low pressure solenoid valve 17 via the first check valve 18. The first check valve 18 only allows the refrigerant to flow from the low pressure solenoid valve 17 side to the fifth three-way joint 28 side.

  The outdoor heat exchanger 16 is disposed in the engine room, and exchanges heat between the refrigerant circulating inside and the air outside the vehicle (outside air) blown from the blower fan 16a. The blower fan 16 a is an electric blower in which the rotation speed (the amount of blown air) is controlled by a control voltage output from the air conditioning control device 50.

  Further, the blower fan 16a of the present embodiment blows outdoor air not only to the outdoor heat exchanger 16 but also to a radiator (not shown) that dissipates the cooling water of the engine EG. Specifically, the vehicle exterior air blown from the blower fan 16a flows in the order of the outdoor heat exchanger 16 → the radiator.

  1 to 4 is provided with a cooling water pump (not shown) for circulating the cooling water. This cooling water pump is an electric water pump whose rotation speed (cooling water circulation amount) is controlled by a control voltage output from the air conditioning control device 50.

  One refrigerant inlet / outlet of the second three-way joint 19 is connected to the other refrigerant inlet / outlet of the outdoor heat exchanger 16. The basic configuration of the second three-way joint 19 is the same as that of the first three-way joint 15. Further, the refrigerant inlet side of the high-pressure solenoid valve 20 is connected to another refrigerant inlet / outlet of the second three-way joint 19, and one refrigerant inlet / outlet of the heat exchanger cutoff electromagnetic valve 21 is connected to another refrigerant inlet / outlet. It is connected.

  The high-pressure solenoid valve 20 and the heat exchanger shut-off solenoid valve 21 are refrigerant circuit switching means whose operation is controlled by a control voltage output from the air conditioning control device 50. It is the same. However, the high-pressure solenoid valve 20 and the heat exchanger shut-off solenoid valve 21 are configured as so-called normally open type on-off valves that close in an energized state and open in a non-energized state.

  The refrigerant outlet side of the high-pressure solenoid valve 20 is connected via a second check valve 22 to the throttle mechanism portion inlet side of a temperature type expansion valve 27 described later. The second check valve 22 only allows the refrigerant to flow from the high pressure solenoid valve 20 side to the temperature type expansion valve 27 side.

  One refrigerant inlet / outlet of the third three-way joint 23 is connected to the other refrigerant inlet / outlet of the heat exchanger cutoff electromagnetic valve 21. The basic configuration of the third three-way joint 23 is the same as that of the first three-way joint 15. Further, as described above, the refrigerant outlet side of the fixed throttle 14 is connected to another refrigerant inlet / outlet of the third three-way joint 23, and the refrigerant inlet side of the dehumidifying electromagnetic valve 24 is connected to another refrigerant inlet / outlet. Yes.

  The dehumidifying electromagnetic valve 24 is a refrigerant circuit switching means whose operation is controlled by a control voltage output from the air conditioning control device 50, and its basic configuration is the same as that of the low-pressure electromagnetic valve 17. Further, the dehumidifying electromagnetic valve 24 is also configured as a normally closed type on-off valve. Then, the refrigerant circuit switching means of the present embodiment includes an electric three-way valve 13, a low pressure solenoid valve 17, a high pressure solenoid valve 20, and a heat exchange that are in a predetermined valve open state or a valve closed state when power supply is stopped. It comprises a plurality of (five) solenoid valves, ie, a device cutoff solenoid valve 21 and a dehumidification solenoid valve 24.

  One refrigerant inlet / outlet of the fourth three-way joint 25 is connected to the refrigerant outlet side of the dehumidifying electromagnetic valve 24. The basic configuration of the fourth three-way joint 25 is the same as that of the first three-way joint 15. Further, another refrigerant inlet / outlet of the fourth three-way joint 25 is connected to the throttle mechanism outlet side of the temperature type expansion valve 27, and further, the refrigerant inlet side of the indoor evaporator 26 is connected to another refrigerant inlet / outlet. Yes.

  The indoor evaporator 26 is disposed in the casing 31 of the indoor air-conditioning unit 30 on the upstream side of the blower air flow of the indoor condenser 12, and exchanges heat between the refrigerant circulating in the interior and the blown air so that the blown air is exchanged. A cooling heat exchanger for cooling.

  The temperature-sensing part inlet side of the temperature type expansion valve 27 is connected to the refrigerant outlet side of the indoor evaporator 26. The temperature type expansion valve 27 is a decompression means for cooling that decompresses and expands the refrigerant that has flowed in from the inlet of the throttle mechanism part and flows out from the outlet of the throttle mechanism part to the outside.

  More specifically, in the present embodiment, as the temperature type expansion valve 27, a temperature sensing unit 27a that detects the degree of superheat of the refrigerant on the outlet side of the indoor evaporator 26 based on the temperature and pressure of the refrigerant on the outlet side of the indoor evaporator 26; And a variable throttle mechanism 27b that adjusts the throttle passage area (refrigerant flow rate) so that the degree of superheat of the refrigerant on the outlet side of the indoor evaporator 26 falls within a predetermined range according to the displacement of the temperature sensing unit 27a. An internal pressure equalizing expansion valve housed inside is adopted.

  One refrigerant inlet / outlet of the fifth three-way joint 28 is connected to the temperature sensing part outlet side of the temperature type expansion valve 27. The basic configuration of the fifth three-way joint 28 is the same as that of the first three-way joint 15. Further, as described above, the refrigerant outlet side of the first check valve 18 is connected to another refrigerant inlet / outlet of the fifth three-way joint 28, and the refrigerant inlet side of the accumulator 29 is connected to another refrigerant inlet / outlet. ing.

  The accumulator 29 is a low-pressure side gas-liquid separator that separates the gas-liquid refrigerant flowing into the fifth three-way joint 28 and stores excess refrigerant. Further, the refrigerant inlet of the compressor 11 is connected to the gas-phase refrigerant outlet of the accumulator 29.

  Next, the indoor air conditioning unit 30 will be described. The indoor air conditioning unit 30 is disposed inside the instrument panel (instrument panel) at the foremost part of the vehicle interior, and has a blower 32, the above-described indoor evaporator 26, the indoor condenser 12, The heater core 36, the PTC heater 37, etc. are accommodated.

  The casing 31 forms an air passage for blown air that is blown into the vehicle interior, and is formed of a resin (for example, polypropylene) that has a certain degree of elasticity and is excellent in strength. On the most upstream side of the blown air flow in the casing 31, an inside / outside air switching box (not shown) for switching between the inside air (vehicle compartment air) and the outside air (vehicle compartment outside air) is arranged.

  More specifically, the inside / outside air switching box is formed with an inside air introduction port for introducing inside air into the casing 31 and an outside air introduction port for introducing outside air. Furthermore, an inside / outside air switching door is provided inside the inside / outside air switching box to continuously adjust the opening area of the inside air inlet and the outside air inlet to change the air volume ratio between the inside air volume and the outside air volume. ing.

  Therefore, the inside / outside air switching door constitutes an air volume ratio changing means for switching the suction port mode for changing the air volume ratio between the air volume of the inside air introduced into the casing 31 and the air volume of the outside air. More specifically, the inside / outside air switching door is driven by an electric actuator 62 for the inside / outside air switching door, and the operation of the electric actuator 62 is controlled by a control signal output from the air conditioning controller 50.

  Further, as the suction port mode, the inside air mode in which the inside air introduction port is fully opened and the outside air introduction port is fully closed and the inside air is introduced into the casing 31, and the inside air introduction port is fully closed and the outside air introduction port is fully opened. 31. The outside air mode for introducing outside air into the inside 31. Further, by continuously adjusting the opening area of the inside air introduction port and the outside air introduction port between the inside air mode and the outside air mode, the introduction ratio of the inside air and the outside air is continuously adjusted. There is an inside / outside air mixing mode to change to.

  A blower 32 that blows air sucked through the inside / outside air switching box toward the vehicle interior is disposed on the downstream side of the inside / outside air switching box. The blower 32 is an electric blower that drives a centrifugal multiblade fan (sirocco fan) with an electric motor, and the number of rotations (air flow rate) is controlled by a control voltage output from the air conditioning control device 50.

  The indoor evaporator 26 is disposed on the downstream side of the air flow of the blower 32. Further, on the downstream side of the air flow of the indoor evaporator 26, an air passage such as a cooling cold air passage 33 and a cold air bypass passage 34 for flowing air after passing through the indoor evaporator 26, and a heating cold air passage 33 and a cold air bypass passage 34. A mixing space 35 is formed for mixing the air that has flowed out of the air.

  In the heating cool air passage 33, a heater core 36, an indoor condenser 12, and a PTC heater 37 as heating means for heating the air that has passed through the indoor evaporator 26 are arranged in this order in the air flow direction. Has been. The heater core 36 is a heating heat exchanger that heats the air that has passed through the indoor evaporator 26 by exchanging heat between the cooling water of the engine EG that outputs vehicle driving force and the air that has passed through the indoor evaporator 26. is there.

  The PTC heater 37 is an electric heater that has a PTC element (positive characteristic thermistor), generates heat when supplied with electric power, and heats air after passing through the indoor condenser 12. In addition, the PTC heater 37 of this embodiment is provided with two or more (specifically three), and the air-conditioning control apparatus 50 changes the number of the PTC heaters 37 to energize, and thereby the plurality of PTC heaters 37. The overall heating capacity is controlled.

  On the other hand, the cold air bypass passage 34 is an air passage for guiding the air after passing through the indoor evaporator 26 to the mixing space 35 without passing through the heater core 36, the indoor condenser 12, and the PTC heater 37. Accordingly, the temperature of the blown air mixed in the mixing space 35 varies depending on the air volume ratio of the air passing through the heating cool air passage 33 and the air passing through the cold air bypass passage 34.

  Therefore, in the present embodiment, the cold air flowing into the heating cold air passage 33 and the cold air bypass passage 34 on the downstream side of the air flow of the indoor evaporator 26 and on the inlet side of the heating cold air passage 33 and the cold air bypass passage 34 is supplied. An air mix door 38 that continuously changes the air volume ratio is disposed.

  Therefore, the air mix door 38 constitutes a temperature adjusting means for adjusting the air temperature in the mixing space 35 (the temperature of the blown air blown into the vehicle interior). More specifically, the air mix door 38 is driven by an electric actuator 63 for the air mix door, and the operation of the electric actuator 63 is controlled by a control signal output from the air conditioning control device 50.

  Furthermore, a blower outlet (not shown) for blowing out the blown air whose temperature is adjusted from the mixing space 35 to the vehicle interior that is the space to be cooled is disposed at the most downstream portion of the blown air flow of the casing 31. Specifically, the air outlet includes a face air outlet that blows air-conditioned air toward the upper body of the passenger in the passenger compartment, a foot air outlet that blows air-conditioned air toward the feet of the passenger, and an inner surface of the front window glass of the vehicle. A defroster outlet for blowing air conditioned air is provided.

  Further, on the upstream side of the air flow of the face outlet, the foot outlet, and the defroster outlet, a face door for adjusting the opening area of the face outlet, a foot door for adjusting the opening area of the foot outlet, and the defroster outlet, respectively. A defroster door (none of which is shown) for adjusting the opening area is arranged.

  These face doors, foot doors, and defroster doors constitute the outlet mode switching means for switching the outlet mode, and are connected to the electric actuator 64 for driving the outlet mode door via a link mechanism (not shown). Are operated in conjunction with each other. The operation of the electric actuator 64 is also controlled by a control signal output from the air conditioning controller 50.

  In addition, as the air outlet mode, the face air outlet is fully opened and air is blown out from the face air outlet toward the upper body of the passenger in the passenger compartment. Bi-level mode that blows air toward the upper body and feet, foot mode that fully opens the foot outlet and opens the defroster outlet by a small opening, and mainly blows air from the foot outlet, and the foot outlet and defroster There is a foot defroster mode in which the air outlet is opened to the same extent and air is blown out from both the foot air outlet and the defroster air outlet.

  Furthermore, it can also be set as the defroster mode which fully opens a defroster blower outlet and blows air from a defroster blower outlet to the vehicle front window glass inner surface by operating a switch of the operation panel 60 mentioned later by a passenger | crew manually.

  In addition, the hybrid vehicle to which the vehicle air conditioner 1 of the present embodiment is applied includes an electric heat defogger (not shown) separately from the vehicle air conditioner. The electric heat defogger is a heating wire disposed inside or on the surface of the vehicle interior window glass, and prevents fogging or window fogging by heating the window glass. The operation of the electric heat defogger can be controlled by a control signal output from the air conditioning controller 50.

  Next, the electric control unit of this embodiment will be described with reference to FIG. The air conditioning control device 50 is composed of a well-known microcomputer including a CPU, ROM, RAM, and its peripheral circuits, and performs various calculations and processing based on an air conditioning control program stored in the ROM, and is connected to the output side. The inverter 61 for the electric motor 11b of the compressor 11, the solenoid valves 13, 17, 20, 21, 24 constituting the refrigerant circuit switching means, the blower fan 16a, the blower 32, various electric actuators 62, 63, 64, etc. Control the operation of

  The air-conditioning control device 50 is configured integrally with the above-described control means for controlling various devices. In the present embodiment, in particular, the operation of the electric motor 11b, which is the discharge capacity changing means of the compressor 11, is activated. The configuration (hardware and software) for controlling (refrigerant discharge capacity) is referred to as discharge capacity control means 50a. Of course, the discharge capacity control means 50a may be configured separately from the air conditioning control device 50.

  Further, on the input side of the air-conditioning control device 50, an inside air sensor 51 that detects the vehicle interior temperature Tr, an outside air sensor 52 (outside air temperature detection means) that detects the outside air temperature Tam, and a solar radiation sensor that detects the amount of solar radiation Ts in the vehicle interior. 53, a discharge temperature sensor 54 (discharge temperature detection means) for detecting the discharge refrigerant temperature Td of the compressor 11, and a discharge pressure sensor 55 (discharge pressure detection) for detecting the discharge side refrigerant pressure (high pressure side refrigerant pressure) Pd of the compressor 11. Means), an evaporator temperature sensor 56 (evaporator temperature detecting means) for detecting the temperature of the blown air (evaporator temperature) Te from the indoor evaporator 26, and the first three-way joint 15 and the low pressure solenoid valve 17 are circulated. A suction temperature sensor 57 for detecting the refrigerant temperature Tsi, a cooling water temperature sensor for detecting the engine cooling water temperature Tw, a humidity sensor for detecting the relative humidity of the air in the passenger compartment near the window glass in the passenger compartment, and a window Interior window glass near a temperature sensor for detecting the temperature of the air in the vicinity of Las, and the detection signal of the sensor group, such as a window glass surface temperature sensor for detecting the window glass surface temperature is input.

  Note that the discharge-side refrigerant pressure (high-pressure side refrigerant pressure) Pd of the compressor 11 of the present embodiment is from the refrigerant discharge port side of the compressor 11 to the variable throttle mechanism portion 27b inlet side of the temperature expansion valve 27 in the cooling mode. This is the high-pressure side refrigerant pressure of the cycle to reach, and in the other operation modes, the high-pressure side refrigerant pressure of the cycle from the refrigerant discharge port side of the compressor 11 to the fixed throttle 14 inlet side. The discharge pressure sensor 55 is provided to monitor an abnormal increase in the high-pressure side refrigerant pressure even in a general refrigeration cycle.

  Further, the evaporator temperature sensor 56 specifically detects the heat exchange fin temperature of the indoor evaporator 26. Of course, as the evaporator temperature sensor 56, temperature detection means for detecting the temperature of other parts of the indoor evaporator 26 may be employed, or temperature detection for directly detecting the temperature of the refrigerant itself flowing through the indoor evaporator 26. Means may be employed. Moreover, the detected value of a humidity sensor, a window glass vicinity temperature sensor, and a window glass surface temperature sensor is used in order to calculate the relative humidity RHW of the window glass surface.

  Further, operation signals from various air conditioning operation switches provided on the operation panel 60 disposed near the instrument panel in the front part of the vehicle interior are input to the input side of the air conditioning control device 50. Specifically, various air conditioning operation switches provided on the operation panel (not shown) include an operation switch of the vehicle air conditioner 1, an operation mode switching switch, an outlet mode switching switch, and an air volume setting switch of the blower 32. An interior temperature setting switch, an economy switch for outputting a command for giving priority to power saving of the refrigeration cycle, and the like are provided.

  Next, the operation of this embodiment in the above configuration will be described with reference to FIG. FIG. 6 is a flowchart showing a control process of the vehicle air conditioner 1 of the present embodiment. This control process is executed by supplying power from the battery to the air conditioning control device 50 even when the vehicle system is stopped.

  First, in step S1, it is determined whether or not the pre-air conditioning start switch or the operation switch of the vehicle air conditioner 1 on the operation panel 60 is turned on. When the pre-air conditioning start switch or the vehicle air conditioner operation switch is turned on, the process proceeds to step S2.

  Note that pre-air conditioning is air conditioning control that starts air conditioning in the passenger compartment before a passenger gets into the vehicle. The pre-air conditioning start switch is provided in a wireless terminal (remote control) carried by the passenger. Therefore, the occupant can start the vehicle air conditioner 1 from a location away from the vehicle.

  Furthermore, in the hybrid vehicle to which the vehicle air conditioner 1 of the present embodiment is applied, the battery can be charged by supplying power from the commercial power source (external power source) to the battery. Therefore, the pre-air conditioning is performed for a predetermined time (for example, 30 minutes) when the vehicle is connected to the external power source, and is performed until the remaining battery level is equal to or less than the predetermined amount when the vehicle is not connected to the external power source. It is like that.

  In step S2, initialization of flags, timers, control variables, etc. (initialization), initial alignment of the stepping motor constituting the electric actuator described above, and the like are performed.

  In the next step S3, the operation signal of the operation panel 60 is read and the process proceeds to step S4. Specific operation signals include a vehicle interior set temperature Tset set by a vehicle interior temperature setting switch, an air outlet mode selection signal, a suction port mode selection signal, an air volume setting signal of the blower 32, and the like.

In step S4, the vehicle environmental state signal used for air conditioning control, that is, the detection signals of the sensor groups 51 to 57 described above is read, and the process proceeds to step S5. In step S5, a target blowing temperature TAO of the vehicle cabin blowing air is calculated. Further, in the heating mode, the heating heat exchanger target temperature is calculated. The target blowing temperature TAO is calculated by the following formula F1. TAO = Kset × Tset−Kr × Tr−Kam × Tam−Ks × Ts + C (F1)
Here, Tset is the vehicle interior set temperature set by the vehicle interior temperature setting switch, Tr is the internal air temperature detected by the internal air sensor 51, Tam is the external air temperature detected by the external air sensor 52, and Ts is detected by the solar radiation sensor 53. Is the amount of solar radiation. Kset, Kr, Kam, Ks are control gains, and C is a correction constant.

  Moreover, although the heat exchanger target temperature for heating is basically a value calculated by the above-described formula F1, correction for calculating a value lower than TAO calculated by the formula F1 to suppress power consumption is performed. Sometimes it is done.

  In subsequent steps S6 to S16, control states of various devices connected to the air conditioning control device 50 are determined. First, in step S6, the cooling mode, the heating mode, the first dehumidifying mode and the second dehumidifying mode are selected, and whether or not the PTC heater 37 is energized is determined according to the air conditioning environment state. Details of step S6 will be described with reference to FIG.

  First, in step S61, it is determined whether pre-air conditioning is being performed. When it determines with performing pre air conditioning in step S61, it progresses to step S62 and it is determined whether the external temperature Tam is lower than -3 degreeC. If it is determined in step S62 that the outside air temperature Tam is lower than −3 ° C., it is determined in step S63 that the PTC heater 37 needs to be energized, and the process proceeds to step S7.

  Thus, when the outside temperature Tam is lower than −3 ° C., the reason why it is necessary to energize the PTC heater 37 is that the refrigeration cycle 10 performs heating when the outside temperature Tam is lower than −3 ° C. If this is done, the difference between the high and low pressures of the cycle will increase, the cycle efficiency (COP) will decrease, the refrigerant evaporation temperature in the outdoor heat exchanger 16 will decrease, and the outdoor heat exchanger 16 may be frosted. is there.

  If it is determined in step S62 that the outside air temperature Tam is not lower than −3 ° C., the process proceeds to step S64, and it is determined whether or not the air outlet mode is the face mode. If it is determined in step S64 that the outlet mode is the face mode, the process proceeds to step S65, the COOL cycle is selected, and the process proceeds to step S7. The reason is that the face mode is an operation mode selected mainly in summer, as will be described in step S9 described later.

  When it determines with air outlet mode not being face mode in step S64, it progresses to step S66 and it is determined whether suction port mode is inside air mode. If it is determined in step S66 that the suction port mode is not the inside air mode, the process proceeds to step S70, the HOT cycle is selected, and the process proceeds to step S7.

  When it is determined in step S66 that the suction port mode is the inside air mode, the process proceeds to step S67 on the assumption that window fogging is highly likely. In step S67, a cycle is selected according to the degree of dehumidification required. Specifically, if it is determined in step S67 that 2 (° C.) <2-Te (blow air temperature), it is determined that there is no need for dehumidification, and the process proceeds to step S70, where the HOT cycle is selected. Proceed to step S7.

  If it is determined in step S67 that 1 (° C.) <2-Te ≦ 2 (° C.), it is determined that there is little need for dehumidification, and the process proceeds to step S69, where the DRY_ALL cycle gives priority to heating capacity over dehumidification capacity And proceed to step S7. Further, when 1-Te ≦ 1 (° C.), it is determined that there is a need for dehumidification, the process proceeds to step S68, a DRY_EVA cycle that prioritizes the dehumidification capacity over the heating capacity is selected, and the process proceeds to step S7.

  On the other hand, when it determines with pre air conditioning not being performed in step S61, it progresses to step S71 and it is determined whether the external temperature Tam is lower than -3 degreeC. If it is determined in step S71 that the outside air temperature Tam is lower than −3 ° C., the process proceeds to step S72, the COOL cycle is selected, and the process proceeds to step S7.

  If it is determined in step S71 that the outside air temperature Tam is not lower than −3 ° C., the process proceeds to step S73, and it is determined whether or not the air outlet mode is the face mode. If it is determined in step S73 that the air outlet mode is the face mode, the process proceeds to step S74, the COOL cycle is selected, and the process proceeds to step S7. The reason is the same as in step S64.

  If it is determined in step S73 that the air outlet mode is not the face mode, the process proceeds to step S66 described above.

  In step S <b> 7 shown in FIG. 6, a target air blowing amount of air blown by the blower 32 is determined. Specifically, the blower motor voltage to be applied to the electric motor is determined with reference to the control map stored in advance in the air conditioning control device 50 based on the TAO determined in step S4.

  More specifically, in this embodiment, the blower motor voltage is set to a high voltage near the maximum value in the extremely low temperature region (maximum cooling region) and the extremely high temperature region (maximum heating region) of TAO, and the air volume of the blower 32 is near the maximum air volume. To control. Further, when TAO rises from the extremely low temperature region toward the intermediate temperature region, the blower motor voltage is decreased according to the increase in TAO, and the air volume of the blower 32 is decreased.

  Further, when TAO decreases from the extremely high temperature range toward the intermediate temperature range, the blower motor voltage is decreased in accordance with the decrease in TAO, and the air volume of the blower 32 is decreased. When TAO enters a predetermined intermediate temperature range, the blower motor voltage is set to the minimum value and the air volume of the blower 32 is set to the minimum value.

  In step S8, the inlet mode, that is, the switching state of the inside / outside air switching box is determined. This inlet mode is also determined based on TAO with reference to a control map stored in advance in the air conditioning controller 50. In the present embodiment, priority is given mainly to the outside air mode for introducing outside air. However, the inside air mode for introducing inside air is selected when TAO is in a very low temperature range and high cooling performance is desired. Further, an exhaust gas concentration detecting means for detecting the exhaust gas concentration of the outside air may be provided, and the inside air mode may be selected when the exhaust gas concentration becomes equal to or higher than a predetermined reference concentration.

  In step S9, the air outlet mode is determined. This air outlet mode is also determined based on TAO with reference to a control map stored in advance in the air conditioning controller 50. In this embodiment, as the TAO rises from the low temperature range to the high temperature range, the outlet mode is sequentially switched from the foot mode to the bi-level mode to the face mode.

  Accordingly, the face mode is mainly selected in the summer, the bi-level mode is mainly selected in the spring and autumn, and the foot mode is mainly selected in the winter. Further, when it is determined that the window glass is likely to be fogged based on the relative humidity RHW of the window glass surface calculated from the detection value of the humidity sensor or the like, the foot defroster mode or the defroster mode is selected. You may do it.

  In step S10, the target opening degree SW of the air mix door 38 is calculated based on the TAO, the air temperature Te blown from the indoor evaporator 26 detected by the evaporator temperature sensor 56, and the heater temperature.

Here, the heater temperature is a value determined according to the heating capability of the heating means (the heater core 36, the indoor condenser 12, and the PTC heater 37) disposed in the cold air passage 33 for heating, and is generally The engine coolant temperature Tw can be used for the. Therefore, the target opening degree SW can be calculated by the following formula F2. SW = [(TAO−Te) / (Tw−Te)] × 100 (%) (F2)
SW = 0 (%) is the maximum cooling position of the air mix door 38, and the cold air bypass passage 34 is fully opened and the heating cold air passage 33 is fully closed. On the other hand, SW = 100 (%) is the maximum heating position of the air mix door 38, and the cold air bypass passage 34 is fully closed and the heating cold air passage 33 is fully opened.

  In step S11, the refrigerant discharge capacity (specifically, the rotational speed) of the compressor 11 is determined. Here, a basic method for determining the rotational speed of the compressor 11 will be described. For example, in the cooling mode, the target blowing temperature TEO of the blowing air temperature Te from the indoor evaporator 26 is determined by referring to the control map stored in advance in the air conditioning control device 50 based on the TAO determined in step S4. decide.

  Then, a deviation En (TEO-Te) between the target blowing temperature TEO and the blowing air temperature Te is calculated, and a deviation change rate obtained by subtracting the deviation En-1 and the previously calculated deviation En-1 from the deviation En calculated this time. Based on fuzzy reasoning based on membership functions and rules stored in advance in the air-conditioning control device 50 using Edot (En− (En−1)), the rotation with respect to the previous compressor speed fCn−1 The number change amount ΔfC is obtained.

  In the heating mode, the discharge-side refrigerant pressure (high-pressure side refrigerant pressure) is referred to a control map stored in advance in the air-conditioning control device 50 based on the heating heat exchanger target temperature determined in step S4. A target high pressure PDO of Pd is determined, and a deviation Pn (PDO-Pd) between the target high pressure PDO and the discharge side refrigerant pressure Pd is calculated. Furthermore, using this deviation Pn and deviation change rate Pdot (Pn− (Pn−1)) with respect to previously calculated deviation Pn−1, based on fuzzy inference, A rotation speed change amount ΔfH is obtained.

  The more detailed control content of step S11 of this embodiment is demonstrated using FIG. First, in step S111, a rotational speed change amount ΔfC during the COOL cycle is obtained. Step S111 in FIG. 8 describes a fuzzy rule table used as a rule. In this rule table, ΔfC is determined based on the deviation En and the deviation change rate Edot so that frosting of the indoor evaporator 26 is prevented.

  In step S112, the rotational speed change amount ΔfH in the HOT cycle, the DRY_EVA cycle, and the DRY_ALL cycle is obtained. Step S112 in FIG. 8 describes a fuzzy rule table used as a rule. In this rule table, ΔfH is determined based on the above-described deviation Pn and deviation change rate Pdot so as to prevent an abnormal increase in the high-pressure side refrigerant pressure Pd.

  In subsequent step S113, it is determined whether or not the operation mode (cycle) determined in step S6 is a COOL cycle. If it is determined in step S113 that the operation mode (cycle) determined in step S6 is a COOL cycle, the process proceeds to step S114, and the rotational speed change amount Δf of the compressor 11 is determined to be ΔfC, and step S116 is performed. Proceed to

  On the other hand, if it is determined in step S113 that the operation mode (cycle) determined in step S6 is not a COOL cycle, the process proceeds to step S115, and the rotational speed change amount Δf of the compressor 11 is determined to be ΔfH, and step S116 is performed. Proceed to

  In step S116, the value obtained by adding the rotational speed change amount Δf to the previous compressor rotational speed fn−1 is determined as the temporary compressor rotational speed, and the process proceeds to step S117. Note that the provisional compressor rotation speed in step S116 is not determined every control cycle τ but every predetermined control interval (1 second in the present embodiment).

  In step S117, it is determined whether or not the operation mode (cycle) determined in step S6 is a DRY_ALL cycle. If it is determined in step S117 that the operation mode (cycle) determined in step S6 is the DRY_ALL cycle, the process proceeds to step S118, the minimum rotation speed of the compressor 11 is set to 2000 rpm, and the process proceeds to step S120.

  On the other hand, when it determines with the operation mode (cycle) determined by step S6 not being a DRY_ALL cycle in step S117, it progresses to step S119, sets the minimum rotation speed of the compressor 11 to 1000 rpm, and progresses to step S120.

  In step S120, the larger value of the temporary compressor rotational speed determined in step S116 and the minimum compressor rotational speed determined in steps S118 and S119 is determined as the current compressor rotational speed fn. The process proceeds to step S12.

  In step S <b> 12 shown in FIG. 6, the operation rate (the number of rotations) of the blower fan 16 a that blows outside air toward the outdoor heat exchanger 16 is determined. The basic method for determining the operating rate (number of rotations) of the blower fan 16a of the present embodiment is as follows. That is, the first temporary operating rate (the number of rotations) is determined so that the operating rate (the number of rotations) of the blower fan 16a increases with an increase in the discharge refrigerant temperature Td of the compressor 11, and the engine cooling water temperature Tw The second temporary operation rate (the number of rotations) is determined so that the operation rate (the number of rotations) of the blower fan 16a increases with the increase.

  Further, the larger one of the first and second temporary operating rates (revolutions) is selected, and the selected operating rate (revolutions) is corrected in consideration of noise reduction of the blower fan 16a and vehicle speed. This value is determined as the operating rate (number of rotations) of the blower fan 16a.

  In step S13, the number of operating PTC heaters 37 and the operating state of the electric heat defogger are determined. For example, when the PTC heater 37 is operated in step S6 and the PTC heater 37 needs to be energized, the target opening degree SW of the air mix door 38 is 100% in the heating mode. What is necessary is just to determine according to the difference of internal temperature Tr and the heat exchanger target temperature for heating, when the heat exchanger target temperature for heating cannot be obtained.

  In addition, when there is a high possibility that the window glass is fogged due to the humidity and temperature in the passenger compartment, or when the window glass is fogged, the electric heat defogger is operated.

  Next, in step S14, the operating states of the solenoid valves 13 to 24, which are refrigerant circuit switching means, are determined according to the operation mode determined in step S6 described above. At this time, in this embodiment, in order to realize a refrigerant circuit according to the cycle, each electromagnetic valve is basically controlled so that the refrigerant flow path through which the refrigerant flows is opened, and the high / low pressure relationship of the refrigerant pressure is determined. For the refrigerant flow path through which the refrigerant does not flow, each solenoid valve is set in a non-energized state to suppress power consumption.

  Details of step S14 will be described with reference to the flowchart of FIG. First, in step S141, the operation mode determined in step S6 is read into the memory CYCLE_VALVE. Next, in step S142, it is determined whether or not the vehicle air conditioner 1 is stopped, that is, whether or not to air-condition the vehicle interior.

  If it is determined in step S142 that the vehicle air conditioner 1 is stopped, the memory CYCLE_VALVE is set to the cooling mode (COOL cycle) in step S143, and the process proceeds to step S144. When it determines with the vehicle air conditioner 1 not having stopped in step S142, it progresses to step S144.

  Note that the fact that the vehicle air conditioner 1 is stopped in step S142 does not mean that the operation switch of the vehicle air conditioner 1 of the operation panel 60 has been turned off, but the air volume setting switch of the operation panel 60. Means that the air flow rate of the blower 32 is set to 0 and that the vehicle system itself is stopped.

  In step S144, the operating state of each solenoid valve 13-24 is determined. Specifically, when the memory CYCLE_VALVE is set to the cooling mode (COOL cycle), all the solenoid valves are deenergized. When the memory CYCLE_VALVE is set to the cooling mode (HOT cycle), the electric three-way valve 13, the high-pressure solenoid valve 20, and the low-pressure solenoid valve 17 are energized, and the remaining solenoid valves 21 and 24 are de-energized. And Further, when the memory CYCLE_VALVE is set to the first dehumidification mode (DRY_EVA cycle), the electric three-way valve 13, the low pressure solenoid valve 17, the dehumidification solenoid valve 24, and the heat exchanger shut-off solenoid valve 21 are energized, and the high pressure The solenoid valve 20 is turned off. In addition, when the memory CYCLE_VALVE is set to the second dehumidification mode (DRY_ALL cycle), the electric three-way valve 13, the low pressure solenoid valve 17, and the dehumidification solenoid valve 24 are energized, and the remaining solenoid valves 20 and 21 are turned off. Turn on the power.

  That is, in this embodiment, even if it is a case where it switches to the refrigerant circuit of any operation mode, it is comprised so that supply of the electric power with respect to at least 1 electromagnetic valve among each electromagnetic valves 13-24 may be stopped. .

  In step S15, whether or not the engine EG is requested to be operated is determined. Here, in an ordinary vehicle that obtains driving force for vehicle travel only from the engine EG, the engine is always operated, so that the engine cooling water is also constantly at a high temperature. Therefore, in a normal vehicle air conditioner for a vehicle, sufficient cooling performance can be exhibited by circulating the engine coolant through the heater core 36.

  On the other hand, in the hybrid vehicle as in the present embodiment, if the remaining battery level is sufficient, the vehicle can travel by obtaining the driving force for traveling only from the traveling electric motor. For this reason, even when high heating performance is required, when the engine EG is stopped, the engine coolant temperature only rises to about 40 ° C., and the heater core 36 cannot exhibit sufficient heating performance.

  Therefore, in this embodiment, in order to secure a heat source necessary for heating, even when high heating performance is required, when the engine coolant temperature Tw is lower than a predetermined reference coolant temperature, the air conditioning control device A request signal is output from 50 to an engine control device (not shown) used for controlling the engine EG so as to operate the engine EG.

  As a result, the engine coolant temperature Tw is increased to obtain high heating performance. Such an operation request signal for the engine EG causes the engine EG to operate even when it is not necessary to operate the engine EG as a driving source for vehicle travel. Become. For this reason, it is desirable to reduce the frequency of outputting the operation request signal of the engine EG as much as possible.

  In step S <b> 16, defrost control of the outdoor heat exchanger 16 is performed when frost formation has occurred in the outdoor heat exchanger 16. Here, when the refrigerant evaporating temperature in the outdoor heat exchanger 16 is lowered to about −12 ° C. when causing the refrigerant to exert an endothermic effect in the outdoor heat exchanger 16 as in the heating mode refrigerant circuit, the outdoor heat exchange is performed. It is known that frosting occurs in the vessel 16.

  When such frost formation occurs, outdoor air cannot flow through the outdoor heat exchanger 16, and heat cannot be exchanged between the refrigerant and the outdoor air in the outdoor heat exchanger 16. For this reason, when frost formation occurs in the outdoor heat exchanger 16, a control process for forcibly setting the cooling mode is performed. In the cooling mode refrigerant circuit, the high-pressure refrigerant radiates heat in the outdoor heat exchanger 16 as described later, so that frost generated in the outdoor heat exchanger 16 can be melted.

  In step S17, various devices 61, 13, 17, 20, 21, 24, 16a, 32, 62, 63, 64 are provided from the air conditioning control device 50 so that the control state determined in the above-described steps S6 to S16 is obtained. Control signal and control voltage are output. For example, a control signal is output to the inverter 61 for the electric motor 11b of the compressor 11 so that the rotational speed of the compressor 11 becomes the rotational speed determined in step S11.

  Here, the output of the control signal for each of the electromagnetic valves 13 to 24 executed in step S17 will be described with reference to the flowchart of FIG. 10 and the time chart of FIG.

  First, in step S171, it is determined whether or not the cycle (refrigerant circuit) has been switched in step S6. That is, it is determined whether or not the operation mode has been switched. If it is determined in step S171 that the cycle is not switched, the solenoid valves 13 to 24 are not switched, and the process returns to the control flow for outputting a control signal to other various devices.

  On the other hand, if it is determined in step S171 that the cycle has been switched, the process proceeds to step S172, where the switching is switching from a non-COOL cycle to a COOL cycle, or switching from a COOL cycle to a non-COOL cycle. It is determined whether or not.

  If it is determined in step S172 that the switching is not from the COOL cycle to the COOL cycle, or the switching from the COOL cycle to other than the COOL cycle, the process proceeds to step S180, and each solenoid valve is set so that the cycle after the switching is performed. Control signals are output to 13-24.

  The reason is that the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of each solenoid valve 13 to 24 is small except in the COOL cycle (that is, the HOT cycle, the DRY_EVA cycle, and the DRY_ALL cycle). This is because even if switching between them does not have a significant adverse effect on the durability of each of the solenoid valves 13-24.

  If it is determined in step S172 that the switch is from a non-COOL cycle to a COOL cycle, or a switch from a COOL cycle to a non-COOL cycle, the process proceeds to step S174, where the discharge capacity control unit 50a of the air conditioning control unit 50 The compressor 11 is stopped and it progresses to step S175. That is, the rotation speed of the compressor 11 is set to 0 rpm, and the process proceeds to step S175. This reduces the high-pressure side refrigerant pressure of the cycle.

  In step S175, the process proceeds to step S176 after waiting for elapse of a predetermined reference pressure drop time (specifically, 20 seconds). In step S176, a reference high-pressure side refrigerant pressure f (Tamdisp) stored in advance in the air conditioning control device 50 is determined based on the outside air temperature Tam.

  The reference high-pressure side refrigerant pressure f (Tamdisp) has a negative effect on the durability of each solenoid valve 13-24 because the pressure difference between the inlet-side refrigerant pressure and the outlet-side refrigerant pressure of each solenoid valve 13-24 becomes small. Furthermore, it is the high-pressure side refrigerant pressure on the discharge side of the compressor 11 where it is estimated that the operating sound of the electromagnetic valves 13 to 24 cannot be heard by the occupant.

  Further, according to the experimental study by the present inventors, if the pressure difference between the inlet-side refrigerant pressure and the outlet-side refrigerant pressure of each electromagnetic valve 13-24 is 0.2 MPa or less, the durability of each electromagnetic valve 13-24. Further, it has been found that the operating sounds of the solenoid valves 13 to 24 are not heard by the occupant without adversely affecting the performance.

  In the next step S177, it is determined whether or not the discharge side refrigerant pressure Pd is equal to or lower than the reference high pressure side refrigerant pressure f (Tamdisp) determined in step S176. If it is determined in step S177 that the discharge-side refrigerant pressure Pd is equal to or lower than the reference high-pressure side refrigerant pressure f (Tamdisp), the inlet-side refrigerant pressure and the outlet-side refrigerant pressure of each of the solenoid valves 13 to 24 are Assuming that the pressure difference has decreased, the process proceeds to step S180.

  If it is determined in step S177 that the discharge-side refrigerant pressure Pd is not less than or equal to the reference high-pressure side refrigerant pressure f (Tamdisp), the process proceeds to step S178, and the blowout port mode becomes the defroster mode or the foot defroster mode. It is determined whether or not there is. If it is determined in step S178 that the outlet mode is the defroster mode or the foot defroster mode, the process proceeds to step S180.

  The reason is that when the air outlet mode is in the defroster mode or foot defroster mode, it is necessary to prevent fogging of the window glass or to eliminate window fogging, so priority is given to passenger safety (ensuring visibility). For this reason, the refrigeration cycle 10 must be operated so that anti-fogging or window fogging can be quickly eliminated in preference to improving the durability of the electromagnetic valves 13 to 24 or reducing operating noise.

  If it is determined in step S178 that the outlet mode is not the defroster mode or the foot defroster mode, the process proceeds to step S179, and is determined in advance after the reference high-pressure side refrigerant pressure f (Tamdisp) is determined in step S176. It is determined whether a reference stop time (specifically, 100 seconds) has elapsed. If it is determined in step S179 that the reference stop time has elapsed since the compressor 11 was stopped, the process proceeds to step S180.

  The reason is that if it takes too much time for the discharge-side refrigerant pressure Pd to become equal to or lower than the reference high-pressure side refrigerant pressure f (Tamdisp), the operation of the refrigeration cycle 10 is stopped for a long period of time. This is because the air conditioning feeling becomes worse. Of course, it may be determined whether the reference stop time has elapsed since the compressor 11 was stopped in step S174.

  If it is determined in step S179 that the reference stop time has not elapsed since the reference high-pressure side refrigerant pressure f (Tamdisp) was determined, the process proceeds to step S177. Moreover, in step S180, a control signal is output to each solenoid valve 13-24 so that it may become the cycle after switching, and it progresses to step S181.

  In step S181, the discharge capacity control means 50a of the air conditioning control means 50 operates the compressor 11 again. That is, a control signal is output to the inverter 61 for the electric motor 11b of the compressor 11 so that the rotational speed of the compressor 11 becomes the rotational speed determined in step S11.

  That is, in this embodiment, when the COOL cycle is switched to other than the COOL cycle, or when the COOL cycle is switched to other than the COOL cycle, if the outlet mode is not the defroster mode or the foot defroster mode, As shown in the time chart of FIG. 11, the reference stop time elapses when the discharge-side refrigerant pressure Pd becomes equal to or lower than the reference high-pressure side refrigerant pressure f (Tamdisp) and after the reference high-pressure side refrigerant pressure f (Tamdisp) is determined. The control signal is output to each solenoid valve 13 to 24 at the earlier timing.

  Next, in step S18 shown in FIG. 6, the process waits for the control period τ, and returns to step S3 when it is determined that the control period τ has elapsed. In the present embodiment, the control cycle τ is 250 ms. This is because the air conditioning control in the passenger compartment does not adversely affect the controllability even if the control period is slower than the engine control or the like. Furthermore, it is possible to suppress a communication amount for air conditioning control in the vehicle and to sufficiently secure a communication amount of a control system that needs to perform high-speed control such as engine control.

  Since the vehicle air conditioner 1 of this embodiment is controlled as described above, it operates as follows according to the operation mode selected in the control step S6.

(A) Cooling mode (COOL cycle: see FIG. 1)
In the cooling mode, the air-conditioning control device 50 deenergizes all the solenoid valves, so that the electric three-way valve 13 is located between the refrigerant outlet side of the indoor condenser 12 and one refrigerant inlet / outlet of the first three-way joint 15. , The low pressure solenoid valve 17 is closed, the high pressure solenoid valve 20 is opened, the heat exchanger shut-off solenoid valve 21 is opened, and the dehumidifying solenoid valve 24 is closed.

  Thereby, as shown by the arrow in FIG. 1, the compressor 11 → the indoor condenser 12 → the electric three-way valve 13 → the first three-way joint 15 → the outdoor heat exchanger 16 → the second three-way joint 19 → the high-pressure solenoid valve 20 → Second check valve 22 → Variable throttle mechanism 27b of temperature type expansion valve 27 → Fourth three-way joint 25 → Indoor evaporator 26 → Temperature sensitive part 27a of temperature type expansion valve 27 → Fifth three way joint 28 → Accumulator 29 → A vapor compression refrigeration cycle in which the refrigerant circulates in the order of the compressor 11 is configured.

  In this cooling mode refrigerant circuit, the refrigerant flowing into the first three-way joint 15 from the electric three-way valve 13 does not flow out to the low-pressure solenoid valve 17 side because the low-pressure solenoid valve 17 is closed. Further, the refrigerant flowing from the outdoor heat exchanger 16 into the second three-way joint 19 does not flow out to the heat exchanger shut-off electromagnetic valve 21 side because the dehumidifying electromagnetic valve 24 is closed. Further, the refrigerant flowing out from the variable throttle mechanism 27b of the temperature type expansion valve 27 does not flow out to the dehumidifying electromagnetic valve 24 side because the dehumidifying electromagnetic valve 24 is closed. Further, the refrigerant that has flowed into the fifth three-way joint 28 from the temperature sensing portion 27 a of the temperature type expansion valve 27 does not flow out to the second check valve 22 side due to the action of the second check valve 22.

  Therefore, the refrigerant compressed by the compressor 11 is cooled by exchanging heat with the blown air (cold air) that has passed through the indoor evaporator 26 by the indoor condenser 12 and further cooled by the outdoor heat exchanger 16. It is cooled by exchanging heat and expanded under reduced pressure by the temperature type expansion valve 27. The low-pressure refrigerant decompressed by the temperature type expansion valve 27 flows into the indoor evaporator 26 and absorbs heat from the blown air blown from the blower 32 to evaporate. Thereby, the blown air passing through the indoor evaporator 26 is cooled.

  At this time, since the opening degree of the air mix door 38 is adjusted as described above, a part (or all) of the blown air cooled by the indoor evaporator 26 flows into the mixing space 35 from the cold air bypass passage 34, A part (or all) of the blown air cooled by the indoor evaporator 26 flows into the heating cold air passage 33 and passes through the heater core 36, the indoor condenser 12, and the PTC heater 37, and is reheated to be mixed space. 35.

  Thereby, the temperature of the blast air mixed in the mixing space 35 and blown into the vehicle interior is adjusted to a desired temperature, and the vehicle interior can be cooled. In the cooling mode, although the dehumidifying ability of the blown air is high, the heating ability is hardly exhibited.

  The refrigerant that has flowed out of the indoor evaporator 26 flows into the accumulator 29 via the temperature sensing part 61 a of the temperature type expansion valve 27. The gas-phase refrigerant that has been gas-liquid separated by the accumulator 29 is sucked into the compressor 11 and compressed again.

  Furthermore, in this cooling mode refrigerant circuit, as is apparent from the description of FIG. 1, two different portions in the refrigerant flow path of the refrigeration cycle 10 communicate with each other. In other words, in the cooling mode refrigerant circuit, a closed circuit that does not communicate with other parts is not formed in the refrigerant flow path constituting the refrigeration cycle 10.

(B) Heating mode (HOT cycle: see FIG. 2)
In the heating mode, the air-conditioning control device 50 energizes the electric three-way valve 13, the high-pressure solenoid valve 20, and the low-pressure solenoid valve 17 and de-energizes the remaining solenoid valves 21, 24. The refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet side of the fixed throttle 14 are connected, the low pressure solenoid valve 17 is opened, the high pressure solenoid valve 20 is closed, and the heat exchanger shut-off solenoid valve 21 is opened. Then, the dehumidifying solenoid valve 24 is closed.

  Thereby, as shown by the arrow in FIG. 2, the compressor 11 → the indoor condenser 12 → the electric three-way valve 13 → the fixed throttle 14 → the third three-way joint 23 → the heat exchanger cutoff electromagnetic valve 21 → the second three-way joint 19. → Vapor compression refrigeration cycle in which refrigerant circulates in the order of outdoor heat exchanger 16 → first three-way joint 15 → low pressure solenoid valve 17 → first check valve 18 → fifth three-way joint 28 → accumulator 29 → compressor 11 Is done.

  In the heating mode refrigerant circuit, the refrigerant flowing into the third three-way joint 23 from the fixed throttle 14 does not flow out to the dehumidifying electromagnetic valve 24 side because the dehumidifying electromagnetic valve 24 is closed. Further, the refrigerant flowing into the second three-way joint 19 from the heat exchanger cutoff electromagnetic valve 21 does not flow out to the high pressure solenoid valve 20 side because the high pressure solenoid valve 20 is closed. The refrigerant flowing into the first three-way joint 15 from the outdoor heat exchanger 16 is connected to the refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet side of the fixed throttle 14 by the electric three-way valve 13. It does not flow out to the electric three-way valve 13 side. The refrigerant flowing from the first check valve 18 into the fifth three-way joint 28 does not flow out to the temperature type expansion valve 27 side because the dehumidifying electromagnetic valve 24 is closed.

  Therefore, the refrigerant compressed by the compressor 11 is cooled by exchanging heat with the blown air blown from the blower 32 by the indoor condenser 12. As a result, the blown air passing through the indoor condenser 12 is heated. At this time, since the opening degree of the air mix door 38 is adjusted, similarly to the cooling mode, the temperature of the blown air mixed in the mixing space 35 and blown into the vehicle interior is adjusted to a desired temperature, Heating can be performed. In the heating mode, the dehumidifying ability of the blown air is not exhibited.

  Further, the refrigerant flowing out of the indoor condenser 12 is decompressed by the fixed throttle 14 and flows into the outdoor heat exchanger 16. The refrigerant that has flowed into the outdoor heat exchanger 16 absorbs heat from the vehicle exterior air blown from the blower fan 16a and evaporates. The refrigerant that has flowed out of the outdoor heat exchanger 16 flows into the accumulator 29 through the low-pressure solenoid valve 17, the first check valve 18, and the like. The gas-phase refrigerant that has been gas-liquid separated by the accumulator 29 is sucked into the compressor 11 and compressed again.

(C) First dehumidification mode (DRY_EVA cycle: see FIG. 3)
In the first dehumidifying mode, the air conditioning control device 50 sets the electric three-way valve 13, the low pressure solenoid valve 17, the heat exchanger shut-off solenoid valve 21 and the dehumidification solenoid valve 24 in the energized state, and sets the high pressure solenoid valve 20 in the non-energized state. The electric three-way valve 13 connects the refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet side of the fixed throttle 14, the low pressure solenoid valve 17 is opened, the high pressure solenoid valve 20 is opened, and heat exchange is performed. The device shut-off solenoid valve 21 is closed, and the dehumidifying solenoid valve 24 is opened.

  Thereby, as shown by the arrow in FIG. 3, the compressor 11, the indoor condenser 12, the electric three-way valve 13, the fixed throttle 14, the third three-way joint 23, the dehumidifying solenoid valve 24, the fourth three-way joint 25, and the indoor evaporation. A vapor compression refrigeration cycle in which the refrigerant circulates in the order of the vessel 26 → the temperature sensing part 27 a of the temperature type expansion valve 27 → the fifth three-way joint 28 → the accumulator 29 → the compressor 11.

  In the refrigerant circuit in the first dehumidifying mode, the refrigerant flowing into the third three-way joint 23 from the fixed throttle 14 flows out to the heat exchanger shut-off solenoid valve 21 side because the heat exchanger shut-off solenoid valve 21 is closed. There is nothing. Further, the refrigerant flowing into the fourth three-way joint 25 from the dehumidifying electromagnetic valve 24 does not flow out toward the variable throttle mechanism 27 b side of the temperature type expansion valve 27 due to the action of the second check valve 22. Further, the refrigerant that has flowed into the fifth three-way joint 28 from the temperature sensing portion 27 a of the temperature type expansion valve 27 does not flow out to the first check valve 18 side due to the action of the first check valve 18.

  Therefore, the refrigerant compressed by the compressor 11 is cooled by exchanging heat with the blown air (cold air) after passing through the indoor evaporator 26 by the indoor condenser 12. As a result, the blown air passing through the indoor condenser 12 is heated. The refrigerant flowing out of the indoor condenser 12 is decompressed by the fixed throttle 14 and flows into the indoor evaporator 26.

  The low-pressure refrigerant flowing into the indoor evaporator 26 absorbs heat from the blown air blown from the blower 32 and evaporates. Thereby, the blown air passing through the indoor evaporator 26 is cooled and dehumidified. Therefore, the blown air cooled and dehumidified by the indoor evaporator 26 is reheated when passing through the heater core 36, the indoor condenser 12, and the PTC heater 37 and blown out from the mixing space 35 into the vehicle interior. That is, dehumidification in the passenger compartment can be performed. In the first dehumidifying mode, the dehumidifying capacity of the blown air can be exhibited, but the heating capacity is small.

  The refrigerant that has flowed out of the indoor evaporator 26 flows into the accumulator 29 via the temperature sensing part 61 a of the temperature type expansion valve 27. The gas-phase refrigerant that has been gas-liquid separated by the accumulator 29 is sucked into the compressor 11 and compressed again.

(D) Second dehumidification mode (DRY_ALL cycle: see FIG. 4)
In the second dehumidifying mode, the air conditioning control device 50 sets the electric three-way valve 13, the low pressure electromagnetic valve 17, and the dehumidifying electromagnetic valve 24 in the energized state and the remaining electromagnetic valves 20 and 21 in the non-energized state. 13 connects between the refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet side of the fixed throttle 14, the low pressure solenoid valve 17 is opened, the high pressure solenoid valve 20 is opened, and the heat exchanger shut-off solenoid valve 21. Is opened, and the dehumidifying electromagnetic valve 24 is opened.

  Thereby, as shown by the arrow in FIG. 4, the compressor 11 → the indoor condenser 12 → the electric three-way valve 13 → the fixed throttle 14 → the third three-way joint 23 → the heat exchanger cutoff electromagnetic valve 21 → the second three-way joint 19. The refrigerant circulates in the order of the outdoor heat exchanger 16 → the first three-way joint 15 → the low pressure solenoid valve 17 → the first check valve 18 → the fifth three-way joint 28 → the accumulator 29 → the compressor 11, and the compressor 11 → Condenser 12 → Electric three-way valve 13 → Fixed throttle 14 → Third three-way joint 23 → Dehumidification solenoid valve 24 → Fourth three-way joint 25 → Indoor evaporator 26 → Temperature sensitive valve 27a of temperature type expansion valve 27 → Fifth three-way A vapor compression refrigeration cycle in which the refrigerant circulates in the order of the joint 28 → accumulator 29 → compressor 11 is configured.

  In other words, in the second dehumidifying mode, the refrigerant flowing from the fixed throttle 14 to the third three-way joint 23 flows out to both the heat exchanger shut-off solenoid valve 21 side and the dehumidifying solenoid valve 24 side, and from the first check valve 18. Both the refrigerant flowing into the fifth three-way joint 28 and the refrigerant flowing into the fifth three-way joint 28 from the temperature sensing part 27a of the temperature type expansion valve 27 merge at the fifth three-way joint 28 and flow out to the accumulator 29 side.

  In the refrigerant circuit in the second dehumidifying mode, the refrigerant that has flowed from the outdoor heat exchanger 16 into the first three-way joint 15 is such that the electric three-way valve 13 is connected to the refrigerant outlet side of the indoor condenser 12 and the refrigerant inlet of the fixed throttle 14. As a result, the electric three-way valve 13 does not flow out. Further, the refrigerant flowing into the fourth three-way joint 25 from the dehumidifying electromagnetic valve 24 does not flow out toward the variable throttle mechanism 27 b side of the temperature type expansion valve 27 due to the action of the second check valve 22.

  Therefore, the refrigerant compressed by the compressor 11 is cooled by exchanging heat with the blown air (cold air) after passing through the indoor evaporator 26 by the indoor condenser 12. As a result, the blown air passing through the indoor condenser 12 is heated. The refrigerant flowing out of the indoor condenser 12 is depressurized by the fixed throttle 14, branched by the third three-way joint 23, and flows into the outdoor heat exchanger 16 and the indoor evaporator 26.

  The refrigerant that has flowed into the outdoor heat exchanger 16 absorbs heat from the vehicle exterior air blown from the blower fan 16a and evaporates. The refrigerant that has flowed out of the outdoor heat exchanger 16 flows into the fifth three-way joint 28 via the low pressure solenoid valve 17, the first check valve 18, and the like. The low-pressure refrigerant flowing into the indoor evaporator 26 absorbs heat from the blown air blown from the blower 32 and evaporates. Thereby, the blown air passing through the indoor evaporator 26 is cooled and dehumidified.

  Therefore, the blown air cooled and dehumidified by the indoor evaporator 26 is reheated when passing through the heater core 36, the indoor condenser 12, and the PTC heater 37 and blown out from the mixing space 35 into the vehicle interior. At this time, in the second dehumidifying mode, the amount of heat absorbed by the outdoor heat exchanger 16 can be radiated by the indoor condenser 12 as compared to the first dehumidifying mode, so that the blown air is more than in the first dehumidifying mode. Can be heated to high temperatures. That is, in the second dehumidifying mode, it is possible to perform dehumidifying heating that also exhibits a dehumidifying capability while exhibiting a high heating capability.

  The refrigerant that has flowed out of the indoor evaporator 26 flows into the fifth three-way joint 28, merges with the refrigerant that flows out of the outdoor heat exchanger 16, and flows into the accumulator 29. The gas-phase refrigerant that has been gas-liquid separated by the accumulator 29 is sucked into the compressor 11 and compressed again.

  Further, as described above, the cooling mode refrigerant circuit, the heating mode refrigerant circuit, and the first dehumidification mode refrigerant circuit all use the outdoor heat exchanger 16 and the indoor heat exchanger ( Specifically, it is a refrigerant circuit in a single heat exchanger mode that circulates to either the indoor condenser 12 or the indoor evaporator 26), and the refrigerant circuit in the second dehumidifying mode is sucked into the compressor 11. The refrigerant circuit is in a combined heat exchanger mode in which the refrigerant is circulated through both the outdoor heat exchanger 16 and the indoor heat exchanger (specifically, the indoor evaporator 26).

  Since the vehicle air conditioner of the present embodiment is configured and operated as described above, the following excellent effects can be exhibited.

  (A) In the refrigeration cycle 10 of the present embodiment, it is possible to switch to a cooling mode refrigerant circuit (COOL cycle) by stopping the supply of electric power to the solenoid valves 13 to 24 that are refrigerant circuit switching means. In the cooling mode, it is possible to avoid the temperature of the electromagnetic valves 13 to 24 themselves from increasing and promoting the deterioration of the coils and the like. That is, deterioration of the durability of the refrigerant circuit switching means can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

  Furthermore, since the cooling mode is mainly used in summer, the temperature in the engine room where the solenoid valves 13 to 24 are arranged is likely to be higher than in other seasons. For this reason, if electric power is continuously supplied to each solenoid valve 13-24 in summer, it will be easy to cause the temperature rise of each solenoid valve 13-24 itself. In this respect, it is very effective to be able to suppress the temperature rise of the electromagnetic valves 13 to 24 themselves in the cooling mode.

  And since the supply of electric power to each solenoid valve 13-24 is stopped at the time of the cooling mode whose use frequency is higher than the refrigerant circuit (HOT cycle) of heating mode, the power consumption as the whole vehicle air conditioner can be reduced. . As a result, power consumption can be reduced throughout the year.

  (B) When the vehicle air conditioner 1 is stopped in the control step S142, that is, when the operation switch of the vehicle air conditioner 1 is turned OFF, the air volume of the blower 32 is set to 0 by the air volume setting switch. When it is determined that the air conditioning of the vehicle interior is not performed, such as when the vehicle system is stopped or when the vehicle system itself is stopped, the control mode is switched to the cooling mode (COOL cycle) in the control step S143.

  Therefore, the power consumption consumed by the refrigerant circuit switching means (13 to 24) of the vehicle air conditioner can be reduced to zero when the vehicle interior is not air-conditioned.

  Furthermore, when the vehicle air conditioner is activated, the operation in the cooling mode can be promptly executed. In general, the difference between the outside air temperature and the desired air conditioning temperature in the passenger compartment is greater than that in the winter heating mode. This is effective in improving the air conditioning feeling.

  (C) As explained in the control step S144, in the refrigeration cycle 10 of the present embodiment, at least one electromagnetic among the solenoid valves 13 to 24 even when the refrigerant circuit is switched to any operation mode. It is comprised so that supply of the electric power with respect to a valve may be stopped.

  Therefore, when switching to a refrigerant circuit different from the cooling mode, the power consumption of the entire vehicle air conditioner can be reduced and the electromagnetic valves 13 to The use frequency of 24 can be reduced and deterioration of durability can be suppressed.

  In other words, in the refrigerant circuit different from the cooling mode, the supply of electric power to the electromagnetic valves that are not directly related to the refrigerant circuit is stopped, so that all the electromagnetic valves 13 to 24 are energized. Thus, the power consumption of the entire vehicle air conditioner can be reduced.

  (D) The refrigeration cycle 10 of the present embodiment is configured such that two different portions in the refrigerant flow path constituting the refrigeration cycle 10 communicate with each other when switched to the cooling mode refrigerant circuit. Therefore, before filling the refrigerant when the refrigeration cycle 10 is manufactured, it is possible to perform evacuation in all refrigerant flow paths constituting the refrigeration cycle 10 by switching to the cooling mode refrigerant circuit and performing evacuation. it can. Furthermore, since it is not necessary to supply power to the solenoid valves 13 to 24 when evacuating, power consumption during evacuation can be reduced.

  (E) As described in the control steps S117 to S119, in the vehicle air conditioner 1 of the present embodiment, the compressor 11 depends on whether or not the operation mode (cycle) is the second dehumidification mode (DRY_ALL cycle). The minimum number of revolutions is changed. More specifically, the minimum rotation speed of the compressor 11 in the second dehumidification mode that is the combined heat exchanger mode is set higher than the minimum rotation speed of the compressor 11 in the single heat exchanger mode other than the second dehumidification mode. ing.

  That is, the rotational speed of the compressor 11 in the composite heat exchanger mode tends to be higher than the rotational speed of the compressor 11 in the single heat exchanger mode. As a result, the refrigerant flow is branched in a combined heat exchanger mode in which the refrigerant flows through two heat exchangers (specifically, the outdoor heat exchanger 16 and the indoor evaporator 26) arranged in parallel. Even if it exists, the fall of the refrigerant | coolant flow volume which distribute | circulates two heat exchangers can be suppressed.

  Therefore, it is possible to suppress the refrigeration oil from staying in the outdoor heat exchanger 16 and the indoor evaporator 26. As a result, the refrigeration oil can be appropriately returned to the compressor 11 and the electromagnetic valves 13 to 24, and deterioration of the durability of the compressor 11 and the refrigerant circuit switching means 13 to 24 can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

  (F) As described in the control step S177, in the refrigeration cycle 10 of the present embodiment, after the compressor 11 is stopped, the high-pressure side refrigerant pressure Pd is a predetermined reference high-pressure side refrigerant pressure f (Tamdisp). Since the refrigerant circuit is switched when it becomes below, each electromagnetic valve 13-24 can be operated after the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of each electromagnetic valve 13-24 becomes small. it can.

  Thereby, it can prevent that unnecessary load resulting from a pressure difference is applied to each electromagnetic valve 13-24, and can suppress the deterioration of durability of each electromagnetic valve 13-24. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

  Further, after the pressure difference between the inlet-side refrigerant pressure and the outlet-side refrigerant pressure of each electromagnetic valve 13-24 becomes small, the operation sound of each electromagnetic valve 13-24 is generated by operating each electromagnetic valve 13-24. Get smaller. Therefore, the switching can be performed without giving a sense of incongruity to the occupant when switching the refrigerant circuit.

  Further, as described above, the discharge pressure sensor 55 is a sensor that is employed in a general refrigeration cycle. Therefore, the deterioration of the durability of the solenoid valves 13 to 24 and the operation sound of the solenoid valves 13 to 24 are suppressed. Reduction can be performed without increasing the manufacturing cost of the vehicle air conditioner 1.

  (G) As explained in the control step S176, in the refrigeration cycle 10 of the present embodiment, the reference high-pressure side refrigerant pressure f (Tamdisp) is determined so as to become a low value as the outside air temperature Tam decreases. Yes. Therefore, it is possible to quickly determine that the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of each electromagnetic valve 13 to 24 has become small, and to suppress the deterioration of the durability of each electromagnetic valve 13 to 24. In addition, the operation noise of each electromagnetic valve 13 to 24 can be reduced.

  (H) As described in control step S178, in the refrigeration cycle 10 of the present embodiment, when the outlet mode is switched to the defroster mode or the foot defroster mode, the high-pressure side refrigerant pressure Pd is the reference high-pressure side refrigerant pressure. Even if the pressure is higher than f (Tamdisp), the refrigerant circuit is forcibly switched.

  Accordingly, priority can be given to the anti-fogging of the window glass in the passenger compartment in preference to reducing the operating noise. That is, priority can be given to safety during vehicle travel.

  (I) As explained in control step S179, in the refrigeration cycle 10 of the present embodiment, when the reference stop time has elapsed, the high-pressure side refrigerant pressure Pd is higher than the reference high-pressure side refrigerant pressure f (Tamdisp). However, since the refrigerant circuit is forcibly switched, if it takes time for the high-pressure side refrigerant pressure Pd to drop to the reference high-pressure side refrigerant pressure f (Tamdisp), priority is given to reducing the operating noise, etc. Priority can be given to suppression of deterioration of the air conditioning feeling such as a feeling of heating or a feeling of cooling.

(Second Embodiment)
In the present embodiment, an example in which the output of the control signal for each of the electromagnetic valves 13 to 24 executed in step S17 is changed as shown in the flowchart of FIG. 12 and the time chart of FIG. 13 with respect to the first embodiment. Will be explained. 12 and 13 are drawings corresponding to FIGS. 10 and 11 of the first embodiment, respectively, and the same or equivalent parts as those of the first embodiment are denoted by the same reference numerals. The same applies to the following drawings.

  Specifically, the control steps S176, S177, and S179 of the first embodiment are abolished in the output of control signals to the solenoid valves 13 to 24 that are executed in step S17 of the present embodiment.

  Furthermore, it is determined whether or not a predetermined reference pressure decrease time (specifically 20 seconds) has elapsed in step S175, and a predetermined reference pressure decrease time (specifically 20 seconds) has elapsed. When it is determined, the process directly proceeds to step S180, and when it is determined that the reference pressure drop time has not elapsed, the process proceeds to step S178.

  That is, in this embodiment, when the COOL cycle is switched to other than the COOL cycle, or when the COOL cycle is switched to other than the COOL cycle, if the outlet mode is not the defroster mode or the foot defroster mode, As shown in the time chart of FIG. 13, after the compressor 11 is stopped, a control signal is output to each of the solenoid valves 13 to 24 when the reference pressure drop time has elapsed.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 according to the present embodiment can not only obtain the same effects as (A) to (E) and (H) of the first embodiment, but also exhibits the following excellent effects. can do.

  (J) In the refrigeration cycle 10 of the present embodiment, the refrigerant circuit is switched when the reference pressure decrease time determined in advance in control step S175 has elapsed, so that the inlet-side refrigerant pressure and the outlet-side refrigerant of each solenoid valve 13-24. Each solenoid valve 13-24 can be operated after the pressure difference with a pressure becomes small.

  Thereby, similarly to (F) of 1st Embodiment, the unnecessary load resulting from a pressure difference is prevented from being applied to each solenoid valve 13-24, and the durability of each solenoid valve 13-24 deteriorates. Can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle. Furthermore, switching can be performed without giving a sense of incongruity to the occupant when switching the refrigerant circuit.

  Further, even if it is determined in the control step S171 that the cycle has been switched, the vehicle interior air conditioner 1 on the operation panel 60 is turned on (ON) immediately after the operation switch is turned on (ON). At the time of starting to start air conditioning, the refrigerant circuit may be switched even before the reference pressure drop time has elapsed.

  The reason is that, at the time of starting to start the air conditioning in the passenger compartment, the refrigerant pressure in the refrigeration cycle is equalized, so that even if the refrigerant circuit is switched without waiting for the elapse of the reference time, each of the solenoid valves 13-24. This is because there is little adverse effect on the durability of the resin and the operation sound is small. As a result, the vehicle compartment can be quickly heated or cooled, and the air conditioning feeling of the passenger can be improved.

(Third embodiment)
In the present embodiment, an example in which the output of the control signal for each electromagnetic valve 13 to 24 executed in step S17 is changed as shown in the flowchart of FIG. 14 and the time chart of FIG. 15 with respect to the first embodiment. Will be explained. 14 and 15 correspond to FIGS. 10 and 11 of the first embodiment, respectively.

  Specifically, in the output of control signals to the solenoid valves 13 to 24 executed in step S17 of the present embodiment, the control steps S178 and S180 of the first embodiment are abolished as shown in FIG. Yes. Further, in step S172, it is determined whether or not switching from a cycle other than the COOL cycle to the COOL cycle is performed.

  If it is determined in step S172 that the switching is not from the COOL cycle to the COOL cycle, the process proceeds to step S1801. In step S1801, control signals are output to the high-pressure solenoid valve 20, the heat exchanger cutoff solenoid valve 21, and the dehumidification solenoid valve 24 so that the cycle after switching is performed, and the process proceeds to step S181.

  The reason is that in the HOT cycle, the DRY_EVA cycle, and the DRY_ALL cycle, the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of each solenoid valve 13 to 24 is small, so switching between each cycle (refrigerant circuit) is performed. This is because the durability of the electromagnetic valves 13 to 24 is not greatly adversely affected.

  In Step S177 of this embodiment, when it is determined that the discharge-side refrigerant pressure Pd is not equal to or lower than the reference high-pressure side refrigerant pressure f (Tamdisp), the process proceeds to Step S179. If it is determined in step S177 that the discharge-side refrigerant pressure Pd is equal to or lower than the reference high-pressure side refrigerant pressure f (Tamdisp), the process proceeds to step S1802.

  In step S1802, a control signal is output to the low pressure solenoid valve 17, the high pressure solenoid valve 20, the heat exchanger shut-off solenoid valve 21, and the dehumidification solenoid valve 24 so that the cycle after switching is reached. Then, after elapse of a predetermined elapsed time (specifically, 10 seconds) in step S1803, the process proceeds to step S1804, a control signal is output to the electric three-way valve 13, and the process proceeds to step S181.

  According to the study by the present inventors, when switching from other than the COOL cycle to the COOL cycle, the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the electric three-way valve 13 is different from that of other electromagnetics. It has been found that the pressure difference across the valves 17, 20, 21, 24 is greater. Further, it has been found that the pressure differences in the other solenoid valves 17, 20, 21, 24 are substantially equal.

  That is, in this embodiment, when the mode is switched from other than the COOL cycle to the COOL cycle, if the outlet mode is not the defroster mode or the foot defroster mode, as shown in the time chart of FIG. The solenoid valve is operated in order from a small pressure difference between the pressure and the outlet side refrigerant pressure.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (G) and (I) of the first embodiment, but also exhibits the following excellent effects. can do.

  (K) In the vehicle air conditioner 1 according to the present embodiment, among the electromagnetic valves 13 to 24, the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure is sequentially operated from the electromagnetic valves 17 to 24, in order. Since the refrigerant circuit is switched, first, with respect to the electromagnetic valves 17 to 24 having a small pressure difference, it is possible to prevent an unnecessary load from being applied, and to suppress deterioration in durability, and to reduce the operation noise. Become.

  Furthermore, since the equalization of the refrigerant pressure in the cycle can be promoted by operating the solenoid valves 17 to 24 having a small pressure difference, the solenoid valve to be operated next to the solenoid valves 17 to 24 having a small pressure difference ( The pressure difference of the electric three-way valve 13) can be reduced. Thereby, it is possible to prevent unnecessary load from being applied to the electromagnetic valve (electric three-way valve 13) to be operated next, and to suppress the deterioration of the durability, and to reduce the operating noise. .

  Therefore, it is possible to suppress the deterioration of the durability of each of the electromagnetic valves 13 to 24. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle. Furthermore, the operation sound of each solenoid valve 13-24 can be made small, and a refrigerant circuit can be switched, without giving a passenger discomfort at the time of switching of a refrigerant circuit.

(Fourth embodiment)
In the present embodiment, an example in which the output of control signals for the electromagnetic valves 13 to 24 executed in step S17 is changed as shown in the flowchart of FIG. 16 and the time chart of FIG. 17 with respect to the third embodiment. Will be explained. 16 and 17 are drawings corresponding to FIGS. 10 and 11 of the first embodiment, respectively.

  Specifically, in the output of the control signal to each of the solenoid valves 13 to 24 executed in step S17 of the present embodiment, as shown in FIG. 16, the COOL cycle in step S172 is compared to the third embodiment. It is determined whether or not it is a switch from a cycle other than the COOL cycle. Furthermore, the order of step S1802 and step S1804 is switched.

  According to the study by the present inventors, when switching from the COOL cycle to other than the COOL cycle, the pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure of the electric three-way valve 13 is different from that of other electromagnetics. It has been found that it is less than the pressure difference across the valves 17, 20, 21, 24. Further, it has been found that the pressure differences in the other solenoid valves 17, 20, 21, 24 are substantially equal.

  That is, in this embodiment, when the COOL cycle is switched to other than the COOL cycle, if the outlet mode is not the defroster mode or the foot defroster mode, as shown in the time chart of FIG. The solenoid valve is operated in order from a small pressure difference between the pressure and the outlet side refrigerant pressure.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the third embodiment. Therefore, the vehicle air conditioner 1 of the present embodiment can obtain the same effects as (A) to (G) and (I) of the first embodiment and (K) of the third embodiment.

  Of course, you may combine the output of the control signal with respect to each solenoid valve 13-24 performed by step S17 in 3rd Embodiment and 4th Embodiment. As a result, the same effect as that of (K) of the third embodiment can be obtained both when the COOL cycle is switched to other than the COOL cycle and when the COOL cycle is switched to other than the COOL cycle.

(Fifth embodiment)
In the present embodiment, an example in which step S11 is changed as shown in the flowchart of FIG. 18 with respect to the first embodiment will be described. FIG. 18 is a drawing corresponding to a part of FIG. 8 of the first embodiment.

  Specifically, in step S11 of the present embodiment, step S110 is added to FIG. 8 and, as shown in steps S121 to S124, the current compressor rotation in the HOT cycle, the DRY_EVA cycle, and the DRY_ALL cycle The determination method of the number fn is changed.

  First, in step S110, it is determined whether or not the operation mode (cycle) determined in step S6 is a COOL cycle. When it is determined in step S110 that the operation mode (cycle) determined in step S6 is a COOL cycle, the normal control described in FIG. 8 of the first embodiment is performed.

  In the normal control, the rotational speed change amount ΔfC during the COOL cycle is obtained as in step S111 in FIG. 8, the temporary compressor rotational speed is determined in the same manner as in step S116, and the temporary compressor rotational speed is determined in the same manner as in step S120. It is to determine a larger value as the current compressor rotation speed among the number and the minimum compressor rotation speed (specifically, 1000 rpm).

  If it is determined in step S110 that the operation mode (cycle) determined in step S6 is not a COOL cycle, the control process proceeds in the order of steps S112 → S115 → S116. The control process of steps S112 → S115 → S116 is the same as in the first embodiment.

  In subsequent step S121, the larger value of the temporary compressor rotational speed determined in step S116 and the predetermined minimum rotational speed of the compressor 11 (1000 rpm in the present embodiment) is set as the temporary compressor rotational speed. The number is determined and the process proceeds to step S122. The minimum number of revolutions of the compressor 11 is a value set so that the refrigeration oil can be appropriately returned to the compressor 11.

  In step S122, it is determined whether or not a value (PDO-Pd) obtained by subtracting the high-pressure side refrigerant pressure Pd from the target pressure PDO is equal to or lower than a predetermined reference pressure (specifically, -0.3 MPa). If it is determined in step S122 that PDO−Pd ≦ −0.3, the actual high-pressure side refrigerant pressure is an abnormally high pressure that is 0.3 MPa or more higher than the target pressure, or indoor condensation Assuming that the temperature of the air blown from the container 12 is abnormally high, the process proceeds to step S123.

  In step S123, the discharge capacity control means 50a of the air conditioning control means 50 sets the rotation speed of the compressor 11 to 0 rpm, that is, stops the compressor 11 and proceeds to step S12. When it is determined in step S122 that PDO−Pd ≦ −0.3 is not satisfied, the process proceeds to step S124, and the current compressor speed fn is set as the temporary compressor speed determined in step S121. Proceed to step S12.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (D) and (F) to (I) of the first embodiment, but also has the following superiority. Can exert the effect.

  (L) As in the heating mode (HOT cycle), the first dehumidification mode (DRY_EVA cycle), and the second dehumidification mode (DRY_ALL cycle) of the present embodiment, the high-pressure side refrigerant pressure Pd becomes a predetermined target pressure PDO. In the refrigeration cycle in which the refrigerant discharge capacity of the compressor 11 is controlled, when the pressure difference between the actual discharge-side refrigerant pressure and the target pressure becomes small, the rotational speed of the compressor 11 becomes small and the outdoor heat exchanger 16, The flow rate of the refrigerant flowing through the indoor condenser 12 and the indoor evaporator 26 is reduced.

  On the other hand, in this embodiment, as described in step S121 and step S124, the compressor 11 can be operated at a rotational speed equal to or higher than a predetermined minimum rotational speed. In other words, the compressor 11 can be operated so as to exhibit a refrigerant discharge capacity equal to or higher than a predetermined minimum refrigerant discharge capacity. Therefore, refrigeration oil can be appropriately returned to the compressor 11, and deterioration of the durability of the compressor 11 can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

  On the other hand, if the actual high pressure side refrigerant pressure Pd becomes equal to or higher than the target pressure PDO by causing the compressor 11 to exhibit a refrigerant discharge capacity equal to or higher than the minimum refrigerant discharge capacity, There is a concern about the abnormally high temperature of the air blown from the condenser 12.

  On the other hand, in the present embodiment, as described in Step S121 and Step S124, when the actual high-pressure side refrigerant pressure Pd becomes higher than the reference pressure than the target pressure PDO, the operation of the compressor 11 is performed. The above-mentioned contradiction can be avoided. That is, an abnormally high pressure of the high-pressure side refrigerant pressure Pd and an abnormally high temperature of the air blown from the indoor condenser 12 can be avoided.

(Sixth embodiment)
In the present embodiment, an example in which step S11 is changed as shown in the flowchart of FIG. 19 with respect to the first embodiment will be described. FIG. 19 is a drawing corresponding to FIG. 8 of the first embodiment. Specifically, in step S11 of this embodiment, step S1131 is added to FIG. 8, and steps S114, S115, and S120 are changed to steps S114 ′, S115 ′, and S120 ′. Further, steps S116 to S119 are deleted.

  First, in step S1131, the rotational speed change amount ΔfT is determined based on the discharge refrigerant temperature Td of the compressor 11 with reference to a predetermined control map. This ΔfT is a rotational speed change amount for limiting an increase in the rotational speed of the compressor 11 so as to prevent melting of the casing 31 made of a resin material and the valve body portions of the electromagnetic valves 13 to 24. is there.

  More specifically, the rotational speed change amount ΔfT decreases with an increase in Td when the discharge refrigerant temperature Td of the compressor 11 is within a predetermined temperature range (120 ° C. or more and less than 135 ° C. in the present embodiment). Further, it is determined so that the refrigerant discharge temperature Td of the compressor 11 is maintained at a maximum value (135 ° C. in the present embodiment) or higher in a predetermined temperature range.

  In subsequent step S113, as in the first embodiment, it is determined whether or not the operation mode (cycle) determined in step S6 is a COOL cycle. If it is determined in step S113 that the operation mode (cycle) determined in step S6 is the COOL cycle, the process proceeds to step S114 '. In step S114 ', the rotational speed change amount Δf of the compressor 11 is determined to be a smaller value of ΔfC and ΔfT, and the process proceeds to step S120'.

  On the other hand, if it is determined in step S113 that the operation mode (cycle) determined in step S6 is not a COOL cycle, the process proceeds to step S115 '. In step S115 ', the rotational speed change amount Δf of the compressor 11 is determined to be a smaller value of ΔfH and ΔfT, and the process proceeds to step S120'. In step S120 ', the value obtained by adding the rotational speed change amount Δf to the previous compressor rotational speed fn-1 is determined as the current compressor rotational speed, and the process proceeds to step S12.

  That is, when ΔfT is selected in steps S114 ′ and S115 ′, the discharge refrigerant temperature Td of the compressor 11 is equal to or higher than a predetermined reference discharge refrigerant temperature (120 ° C. in the present embodiment). Moreover, the effect | action which maintains or reduces the refrigerant | coolant discharge capability of the compressor 11 can be exhibited. Further, as the reference discharge refrigerant temperature rises, the degree to which the refrigerant discharge capacity of the compressor 11 is reduced can be increased.

  Of course, when the reference refrigerant discharge temperature is fixed at 120 ° C. and the discharge refrigerant temperature Td of the compressor 11 becomes equal to or higher than the reference discharge refrigerant temperature, the predetermined rotation speed change amount ΔfT may be determined. In this case, ΔfT may be set to 0 so as to maintain the compressor speed fn, or ΔfT may be set negative so that the current compressor speed fn is lower than the previous compressor speed fn−1. It is good also as the value of.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (D) and (F) to (I) of the first embodiment, but also has the following superiority. Can exert the effect.

  (M) As described in the control steps S114 ′ and S115 ′, in the refrigeration cycle 10 of the present embodiment, the compression is performed when the discharge refrigerant temperature Td of the compressor 11 becomes equal to or higher than a predetermined reference discharge refrigerant temperature. The refrigerant discharge capacity of the machine 11 can be maintained or lowered. Therefore, it can be avoided that the discharge refrigerant temperature Td of the compressor 11 rises unnecessarily. As a result, it is possible to suppress deterioration in durability of the resin casing 31 and the valve body portions of the electromagnetic valves 13 to 24.

  Further, since the discharge temperature sensor 54 as the discharge temperature detecting means is provided, for example, the compressor 11 is more accurately compared with the case where the discharge refrigerant temperature Td is calculated (estimated) using the high-pressure side refrigerant pressure Pd. Can be detected. The reason is that when the refrigerant of the cycle is insufficient, the relationship between the refrigerant pressure and the refrigerant temperature does not become a relationship estimated from the saturated gas line on the Mollier diagram.

  Therefore, according to the vehicle air conditioner 1 of this embodiment, the deterioration of the durability of the casing and the deterioration of the durability of the cycle constituent device can be reliably suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

(Seventh embodiment)
In the present embodiment, an example in which Step S11 is changed as shown in the flowchart of FIG. 20 with respect to the first embodiment will be described. FIG. 20 is a drawing corresponding to FIG. 8 of the first embodiment. Specifically, in step S11 of this embodiment, steps S1141 and S1151 are added to steps in FIG. 8, and steps S117 to S119 are deleted.

  When it is determined in step S1141 that the operation mode (cycle) is a COOL cycle, the minimum number of revolutions of the compressor 11 is set to 1000 rpm. In step S1151, it is determined that the operation mode (cycle) is not a COOL cycle. Then, the minimum rotational speed of the compressor 11 is set to 2000 rpm, and the process proceeds to step S116.

  In step S116, the temporary compressor rotational speed is determined in the same manner as in the first embodiment. In the next step S120, as in the first embodiment, a larger value is determined as the current compressor speed among the temporary compressor speed and the minimum compressor speed determined in step S1141 or step S1151. Then, the process proceeds to step S12.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (D) and (F) to (I) of the first embodiment, but also has the following superiority. Can exert the effect.

  (N) As described in the control steps S1141 and S1151, in the vehicle air conditioner 1 of the present embodiment, the minimum of the compressor 11 depends on whether or not the operation mode (cycle) is the cooling mode (COOL mode). The rotational speed is changed. More specifically, the minimum rotation speed of the compressor 11 in the cooling mode (COOL cycle) is set higher than the minimum rotation speed of the compressor 11 in other than the cooling mode.

  Thereby, when it switches to cycles other than a COOL cycle, the refrigerant | coolant discharge capability of the compressor 11 becomes easy to increase rather than a COOL cycle. Accordingly, the flow rate of the refrigerant flowing through the outdoor heat exchanger 16 can be increased when switching to a cycle other than the COOL cycle in which the viscosity of the refrigerating machine oil tends to be higher than the COOL cycle due to a decrease in the outside air temperature Tam.

  As a result, the refrigerating machine oil can be prevented from staying in the outdoor heat exchanger 16, and the refrigerating machine oil can be appropriately returned to the compressor 11 and the electromagnetic valves 13 to 24. The deterioration of the durability of the valves 13 to 24 can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

(Eighth embodiment)
In the present embodiment, an example in which step S11 is changed as shown in the flowcharts of FIGS. 21 and 22 with respect to the first embodiment will be described. 21 and 22 are drawings corresponding to FIG. 8 of the first embodiment. Specifically, in step S11 of this embodiment, steps S125 to S131 are added to steps in FIG. 8 and steps S116 to S120 are deleted.

  In step S125 of FIG. 21, the predicted discharge refrigerant temperature STd is obtained based on the high-pressure side refrigerant pressure Pd detected by the discharge pressure sensor 55. In the refrigeration cycle 10 in which the accumulator 29 is provided on the suction side of the compressor 11 like the refrigeration cycle 10 of the vehicle air conditioner 1 of the present embodiment, the refrigerant sucked by the compressor 11 becomes a saturated gas phase refrigerant. The discharge refrigerant temperature of the compressor 11 can be estimated based on the high-pressure side refrigerant pressure Pd.

  Therefore, in the present embodiment, the predicted discharge refrigerant temperature STd is estimated based on the high-pressure side refrigerant pressure Pd with reference to the control map shown in Step S125 stored in advance in the air conditioning control device 50.

  Next, in step S126 of FIG. 22, it is determined whether or not the high-pressure side refrigerant pressure Pd is larger than 0.19 MPa and smaller than 2.01 MPa. That is, it is determined whether 0.19 <Pd <2.01. If 0.19 <Pd <2.01 is not satisfied in step S126, the process proceeds to step S127, the maximum rotation speed of the compressor 11 is set to 10,000 rpm, and the process proceeds to step S130.

  If 0.19 <Pd <2.01 in step S126, the process proceeds to step S128. In step S128, the absolute value of the value obtained by subtracting the predicted discharge refrigerant temperature STd estimated in step S125 from the discharge refrigerant temperature Td detected by the discharge temperature sensor 54 becomes 30% or more of the predicted discharge refrigerant temperature STd. It is determined whether or not.

  Thereby, it is determined whether or not the refrigerant in the refrigeration cycle 10 is insufficient. As described above, in the refrigeration cycle 10 in which the accumulator 29 is provided on the suction side of the compressor 11, since the refrigerant sucked by the compressor 11 becomes a saturated gas phase refrigerant, the estimation can be performed based on the high-pressure side refrigerant pressure Pd. it can. However, when the refrigerant in the refrigeration cycle 10 is insufficient, the liquid phase refrigerant cannot be stored in the accumulator 29.

  As a result, the degree of superheat of the refrigerant sucked by the compressor 11 increases, and the discharge refrigerant temperature Td also increases. Therefore, in this embodiment, when the discharge refrigerant temperature Td and the predicted discharge refrigerant temperature STd are different from each other by 30% or more of the predicted discharge refrigerant temperature STd, it is determined that the refrigerant in the refrigeration cycle 10 is insufficient. Yes. Note that the range of 0.19 <Pd <2.01 in step S126 is set as a range in which the lack of the refrigerant can be accurately determined.

  When the absolute value of the value obtained by subtracting the predicted discharge refrigerant temperature STd from the discharge refrigerant temperature Td in step S128 is 30% or more of the predicted discharge refrigerant temperature STd, the process proceeds to step S129, and the maximum rotation of the compressor 11 is performed. The number is set to 0 rpm, and the process proceeds to step S130. If the absolute value of the value obtained by subtracting the predicted discharge refrigerant temperature STd from the discharge refrigerant temperature Td is not 30% or more of the predicted discharge refrigerant temperature STd in step S128, the process proceeds to step S127.

  In step S130, the temporary compressor rotational speed is determined in the same manner as in step S113 of the first embodiment. In the next step S131, a smaller value is determined as the current compressor rotational speed among the temporary compressor rotational speed and the maximum compressor rotational speed determined in step S127 or S129, and the process proceeds to step S12.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (D) and (F) to (I) of the first embodiment, but also has the following superiority. Can exert the effect.

  (O) As explained in control step S128, in the vehicle air conditioner 1 of the present embodiment, the absolute value of the value obtained by subtracting the predicted discharge refrigerant temperature STd from the discharge refrigerant temperature Td is the predetermined reference temperature difference. When the value reaches 30% or more of the set predicted discharge refrigerant temperature STd, it is determined that the refrigerant in the refrigeration cycle 10 is insufficient, and the maximum rotation speed of the compressor 11 is set to 0 rpm.

  Thereby, the compressor 11 can be stopped by setting the rotation speed of the compressor 11 to 0 rpm in step S131. Therefore, the discharge refrigerant temperature Td of the compressor 11 can be avoided from increasing abnormally, and deterioration of the durability of the casing 31 and the valve body portions of the electromagnetic valves 13 to 24 can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

(Ninth embodiment)
In the present embodiment, an example in which step S11 is changed as shown in the flowchart of FIG. 23 with respect to the first embodiment will be described. FIG. 23 is a drawing corresponding to FIG. 8 of the first embodiment. Specifically, in step S11 of the present embodiment, steps S132 to S135 are added to FIG. 8 and steps S116 to S120 are deleted.

  In Step 132, if it is determined that at least one of the electromagnetic valves 13 to 24 and the discharge temperature sensor 54 has failed and it is determined that it has failed, the process proceeds to Step S133 with a failure flag = 1. . Therefore, step S132 of this embodiment has the functions of a switching failure determination unit and a discharge temperature failure determination unit.

  The failure of each solenoid valve 13 to 24 is determined that, for example, if the current value flowing through each solenoid valve 13 to 24 is abnormally increased, the coil of each solenoid valve 13 to 24 is short-circuited and failed. it can. Furthermore, if a current value does not flow through each of the solenoid valves 13 to 24 regardless of the energized state, it can be determined that the solenoid valves 13 to 24 are broken.

  The failure of the discharge temperature sensor 54 can be determined as a failure, for example, when the detection signal of the discharge temperature sensor 54 is maintained at the maximum output or at the minimum output. Furthermore, when the detection signal of the discharge temperature sensor 54 is 0, it can be determined that the discharge temperature sensor 54 is broken.

  In a succeeding step S133, it is determined whether or not the failure flag = 1. If the failure flag is not 1 in step S133, the process proceeds to step S134, the maximum rotation speed of the compressor 11 is set to 10,000 rpm, and the process proceeds to step S130. If the failure flag = 1 in step S133, the process proceeds to step S136, the maximum rotation speed of the compressor 11 is set to 0 rpm, and the process proceeds to step S136.

  In steps S136 and S137, as in steps S130 and S131 of the eighth embodiment, the temporary compressor rotational speed is determined, and the temporary compressor rotational speed and the maximum compressor determined in step S134 or S135 are determined. Among the rotation speeds, a smaller value is determined as the current compressor rotation speed, and the process proceeds to step S12.

  The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of this embodiment can not only obtain the same effects as (A) to (D) and (F) to (I) of the first embodiment, but also has the following superiority. Can exert the effect.

  (P) As described in the control step S132, in the vehicle air conditioner 1 of this embodiment, it is determined whether or not at least one of the electromagnetic valves 13 to 24 and the discharge temperature sensor 54 has failed. When it is determined that a failure has occurred, the maximum rotational speed of the compressor 11 is set to 0 rpm.

  Thereby, the compressor 11 can be stopped by setting the rotation speed of the compressor 11 to 0 rpm in step S137. Therefore, it is possible to suppress the malfunction of each of the solenoid valves 13 to 24 constituting the refrigerant circuit switching means from causing an abnormal increase in the refrigerant pressure in the cycle or the abnormal increase in the refrigerant temperature in the cycle.

  Therefore, an abnormal increase in the refrigerant pressure in the cycle can be suppressed, deterioration of the durability of the cycle component device can be suppressed, and secondary failure of the cycle component device can be suppressed. Furthermore, the abnormal rise of the refrigerant temperature in the cycle can be suppressed, and deterioration of the durability of the cycle component equipment constituting the refrigeration cycle can be suppressed.

(10th Embodiment)
In the present embodiment, an example in which step S6 is changed as shown in the flowchart of FIG. 24 with respect to the first embodiment will be described. FIG. 24 is a drawing corresponding to FIG. 7 of the first embodiment. Specifically, in step S6 of the present embodiment, step S71 in FIG. 8 is changed to step S711.

  In this step S711, it is determined whether or not the outside air temperature Tam is lower than −3 ° C. or higher than 30 ° C. If it is determined in step S711 that the outside air temperature Tam is lower than −3 ° C. or higher than 30 ° C., the process proceeds to step S72, the COOL cycle is selected, and the process proceeds to step S7.

  If the outside air temperature Tam is not lower than −3 ° C. and not higher than 30 ° C. in step S711, that is, if −3 ≦ Tam ≦ 30, the process proceeds to step S73. The overall configuration and control of the other vehicle air conditioners 1 are the same as in the first embodiment. Therefore, the vehicle air conditioner 1 of the present embodiment can not only achieve the same effects as (A) to (I) of the first embodiment, but also can exhibit the following excellent effects. .

  (Q) In the vehicle air conditioner 1 of the present embodiment, as described in step S711, not only when the outside air temperature Tam is lower than −3 ° C., but also higher than 30 ° C., which is a predetermined reference outside air temperature. Sometimes it is switched to the cooling mode refrigerant circuit (COOL cycle). Therefore, even when the outside temperature of the engine room in which the refrigeration cycle 10 is mounted is likely to be high, it is difficult to switch to the heating mode or the first and second dehumidifying modes.

  That is, when switching to the heating mode, it is when it is determined in step S66 that the suction port mode is not the inside air mode during pre-air conditioning, and when switching to the first and second dehumidifying modes, step S66 is performed during pre-air conditioning. When it is determined that the suction port mode is the inside air mode.

  Thus, when the outside air temperature is higher than the reference outside air temperature (30 ° C.), the temperature of the compressor 11 and each of the solenoid valves 13 to 24 is further increased by operating in the heating mode or the first and second dehumidifying modes. Can be suppressed. As a result, deterioration of durability of the compressor 11 and the electromagnetic valves 13 to 24 can be suppressed. As a result, it is possible to suppress the deterioration of the durability of the cycle component equipment constituting the refrigeration cycle.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention.

  (1) The means adopted in each of the above embodiments can be applied to other embodiments. For example, the control in step S11 of the fifth to ninth embodiments can be applied to step S11 of the second to fourth embodiments. Further, the control in step S16 in the tenth embodiment is applicable to step S16 in the second to ninth embodiments.

  (2) In the above-described eighth embodiment, it is determined in step S128 whether or not the refrigerant in the refrigeration cycle 10 is insufficient, and when it is determined that the refrigerant in the refrigeration cycle 10 is insufficient, The operation of the compressor 11 is stopped to reduce the refrigerant discharge capacity. In addition, when it is determined in step S128 that the refrigerant in the refrigeration cycle 10 is insufficient, warning means may be provided to warn the occupant of this.

  Similarly, in the ninth embodiment, warning means may be provided to warn the occupant of a failure of the refrigeration cycle 10 when it is determined in step S133 that the failure flag = 1. In addition, as a warning means, the buzzer etc. which emit the warning lamp | ramp which warns with light, and a sound are employable.

  (3) In the above-described embodiment, an example in which a normal chlorofluorocarbon refrigerant is employed as the refrigerant of the refrigeration cycle 10 has been described, but the type of refrigerant is not limited to this. For example, a hydrocarbon refrigerant or carbon dioxide may be used. Further, the refrigeration cycle 10 may be configured as a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure exceeds the critical pressure of the refrigerant.

  (4) In the above embodiment, for example, in steps S62 and S71 of the first embodiment, it is determined whether or not the outside air temperature Tam is lower than −3 ° C. Of course, the outside air temperature Tam is −3. You may make it determine whether it is below degrees C. or not. Similarly, in step S711 of the tenth embodiment, it may be determined whether or not the outside air temperature Tam is −3 ° C. or lower, or 30 ° C. or higher. The same can be applied to other determination steps within the scope of the present invention.

  (5) The refrigeration cycle 10 applied to the vehicle air conditioner 1 of the present invention described in the above embodiments is applied to a stationary air conditioner, a hot water supply device with an air conditioning function, a cooling / heating device for a vending machine, and the like. May be.

DESCRIPTION OF SYMBOLS 10 Refrigeration cycle 11 Compressor 12 Indoor condenser 13 Electric three-way valve 16 Outdoor heat exchanger 17 Low pressure solenoid valve 20 High pressure solenoid valve 21 Heat exchanger shut-off solenoid valve 24 Dehumidification solenoid valve 26 Indoor evaporator 50 Air conditioning control device 50a Discharge capacity Control means 52 Outside air sensor 54 Discharge temperature sensor 55 Discharge pressure sensor

Claims (7)

Compressor (11) for sucking refrigerant, compressing and discharging, outdoor heat exchanger (16) for heat exchange between refrigerant and outdoor air, and room for heat exchange between refrigerant and blown air blown into vehicle interior A vapor compression refrigeration cycle (10) having heat exchangers (12, 26);
The refrigerating cycle (10) includes a cooling mode refrigerant circuit that cools the blown air by dissipating heat absorbed by the indoor heat exchanger (26) by the outdoor heat exchanger, and the outdoor heat exchanger. (16) having refrigerant circuit switching means (13 to 24) for switching a refrigerant circuit in a heating mode in which the amount of heat absorbed in the indoor heat exchanger (12) is radiated to heat the blown air;
The refrigerant circuit switching means (13 to 24) is a reference high-pressure-side refrigerant pressure after the compressor (11) is stopped and the compressor-side (11) discharge-side high-pressure-side refrigerant pressure (Pd) is predetermined. The vehicle air conditioner is characterized in that the refrigerant circuit is switched when (f (Tamdisp)) or less.   2. The vehicle air conditioner according to claim 1, wherein the reference high-pressure side refrigerant pressure (f (Tamdisp)) is determined to become a low value as the outside air temperature decreases. Furthermore, it comprises a blower outlet mode switching means for switching the wind direction of the blown air blown into the vehicle interior,
The refrigerant circuit switching means (13 to 24) is configured such that when the air outlet mode switching means is switching the air outlet mode to a mode in which the blown air is blown out toward the window in the vehicle interior, The vehicle air conditioner according to claim 1 or 2, wherein the refrigerant circuit is switched even when the refrigerant pressure (Pd) is higher than the reference high-pressure side refrigerant pressure (f (Tamdisp)).   The refrigerant circuit switching means (13 to 24) determines that the high-pressure side refrigerant pressure (Pd) is equal to the reference high-pressure side refrigerant pressure when a predetermined reference stop time has elapsed since the compressor (11) was stopped. The vehicle air conditioner according to any one of claims 1 to 3, wherein the refrigerant circuit is switched even at a pressure higher than (f (Tamdisp)).   The refrigerant circuit switching means (13 to 24) is configured so that the high-pressure side refrigerant comes after the compressor (11) is stopped and a predetermined reference pressure drop time has elapsed since the compressor (11) was stopped. When the pressure (Pd) is compared with the reference high-pressure side refrigerant pressure (f (Tamdisp)) and the high-pressure side refrigerant pressure (Pd) is equal to or lower than the reference high-pressure side refrigerant pressure (f (Tamdisp)), The vehicle air conditioner according to any one of claims 1 to 4, wherein the refrigerant circuit is switched.   The said refrigerant circuit switching means (13-24) switches the said refrigerant circuit at the time of the start which starts the air conditioning of the said vehicle interior, even before the said reference pressure fall time passes. The vehicle air conditioner described. The refrigerant circuit switching means is composed of a plurality of solenoid valves (13 to 24) that are operated by being supplied with electric power,
After the compressor (11) is stopped, the plurality of solenoid valves (13 to 24) are operated in order from solenoid valves (13 to 24) having a small pressure difference between the inlet side refrigerant pressure and the outlet side refrigerant pressure. The vehicle air conditioner according to claim 1, wherein the refrigerant circuit is switched.

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