JP2004161219A - Air-conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner for a vehicle constituting a hot gas heater cycle capable of suppressing inconvenience such as blurring etc. of a window pane of the vehicle. <P>SOLUTION: The air-conditioner for a vehicle is structured so that a discharged gas refrigerant from a compressor is decompressed by a hot gas bypass passage and the hot gas heater cycle to actuate an intra-cabin heat exchanger as a radiator is set, wherein judgement is made whether the suction mode set by an inner-outer air changeover means is the outer air mode (S40), and when the suction mode is the outer air mode, the heating mode due to the hot gas heater cycle H is executed (S50). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a hot gas that causes the indoor heat exchanger to act as a gas refrigerant radiator by directly introducing the compressor discharge gas refrigerant (hot gas) into the indoor heat exchanger while bypassing the outdoor heat exchanger during heating. The present invention relates to a vehicle air conditioner that exhibits a gas heating function.
[0002]
[Prior art]
Conventionally, in a vehicle air conditioner, warm water (engine cooling water) is circulated through a heating heat exchanger during heating in winter, and the heating heat exchanger heats the conditioned air using the hot water as a heat source. In this case, when the temperature of the hot water is low, the temperature of the air blown into the vehicle interior may decrease, and the required heating capacity may not be obtained.
[0003]
Therefore, a vehicle air conditioner having a hot gas heater cycle that exhibits a hot gas heating function during heating has been proposed (see Patent Document 1). In this conventional device, a hot gas bypass passage directly connecting the compressor discharge side and the inlet side of the indoor heat exchanger is provided, and a heating decompression device is provided in the hot gas bypass passage.
[0004]
When the temperature of the hot water is lower than the predetermined temperature, for example, immediately after the start of the vehicle engine during the heating in winter, the refrigerant passage of the air conditioning refrigeration cycle is switched to activate the hot gas heater cycle, and the compressor discharge gas refrigerant (hot gas ) Flows into the hot gas bypass passage, and the discharged gas refrigerant is depressurized through the hot gas bypass passage, and then directly introduced into the indoor heat exchanger. This makes it possible to exhibit the auxiliary heating function by releasing heat from the high-temperature gas refrigerant to the conditioned air in the indoor heat exchanger.
[0005]
[Patent Document 1]
JP-A-5-272817
[Problems to be solved by the invention]
By the way, in the refrigeration cycle for air conditioning, the hot gas heater cycle is designed to operate when the temperature of hot water, which is a heating heat source of the vehicle, is low. Therefore, when the hot gas heater cycle is operating, the temperature of air blown into the vehicle compartment is relatively low. It is in a low state. Therefore, the window glass temperature of the vehicle is also low, close to the outside air temperature.
[0007]
As a result, when the inside air mode is selected as the suction mode of the vehicle air conditioner, the humid inside air humidified by the occupant's breathing or the like is heated and blown out to the inner surface of the window glass of the vehicle. Therefore, there is a problem that air near the inner surface of the window glass is cooled by the window glass to reach the dew point and fog occurs on the window glass.
[0008]
When the hot gas heater cycle is operating, the high pressure is detected to control the capacity of the compressor.For example, if a fixed displacement compressor is used, the operation of the compressor depends on the high pressure. Control intermittently. At this time, if the suction mode of the vehicle air conditioner is in the inside air mode, the amount of heat released in the indoor heat exchanger is significantly reduced as compared with the outside air mode, and the low pressure increases. For this reason, the rising speed of the high pressure increases, and the frequency of the intermittent operation of the compressor increases, thereby increasing discomfort such as shock and noise due to the intermittent operation of the compressor.
[0009]
An object of the present invention is to suppress the above-mentioned problems in a vehicle air conditioner constituting a hot gas heater cycle.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the refrigerant discharged from the compressor (10) is depressurized by the hot gas bypass passage (20) and introduced into the indoor heat exchanger (18). In a vehicle air conditioner for setting a hot gas heater cycle (H) for operating an indoor heat exchanger (18) as a radiator,
It is characterized in that it is determined whether the suction mode set by the inside / outside air switching means (72) is the outside air mode, and when the suction mode is the outside air mode, the heating mode by the hot gas heater cycle (H) is executed.
[0011]
By the way, the absolute humidity of the outside air is low at a low outside air temperature when the hot gas heater cycle (H) is operated. Therefore, by executing the heating mode using the hot gas heater cycle (H) only in the outside air mode as described in claim 1, even if the vehicle interior blowing temperature does not rise to a sufficiently high temperature in the hot gas heating mode, the vehicle The fogging of the window glass can be reliably prevented.
[0012]
As in the second aspect of the present invention, specifically, in the first aspect, the heating mode by the hot gas heater cycle (H) is executed only when the suction mode is the outside air mode, and the suction mode is set to the inside air mode. In some cases, execution of the heating mode by the hot gas heater cycle (H) may be prohibited.
[0013]
Further, as in the invention according to claim 3, in claim 1, specifically, when the suction mode is the inside air mode, after switching the suction mode to the outside air mode, heating by the hot gas heater cycle (H) is performed. The mode may be executed.
[0014]
Thus, when the heating mode is started by the hot gas heater cycle (H), even if the suction mode is the inside air mode, the suction mode can be switched to the outside air mode to execute the hot gas heating mode.
[0015]
According to a fourth aspect of the present invention, in any one of the first to third aspects, there is provided a hot gas heating command means (29b) for issuing a command signal of a heating mode by a hot gas heater cycle (H), wherein the command signal is provided. Is determined when the suction mode is displayed.
[0016]
According to this, when a heating mode command signal is output from the hot gas heating command means (29b), it is possible to determine the suction mode and determine whether to execute the hot gas heating mode.
[0017]
In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means described in embodiment mentioned later.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
FIG. 1 illustrates the overall configuration of the vehicle air conditioner according to the first embodiment. The compressor 10 is driven by a water-cooled vehicle engine 12 via an electromagnetic clutch 11, and is composed of, for example, a fixed displacement swash plate type compressor.
[0019]
The discharge side of the compressor 10 is connected to a condenser 14 via a cooling electromagnetic valve 13, and the outlet side of the condenser 14 is connected to a receiver 15 for separating gas-liquid refrigerant and storing the liquid refrigerant. . The condenser 14 is an outdoor heat exchanger that is disposed in the vehicle engine room together with the compressor 10 and the like and exchanges heat with the outside air (cooling air) blown by the electric cooling fan 14a. The cooling fan 14a is an electric fan driven by a motor 14b.
[0020]
The outlet side of the liquid receiver 15 is connected to a temperature-type expansion valve 16 forming a cooling decompression device. The outlet side of the thermal expansion valve 16 is connected to the inlet side of an evaporator 18 via a check valve 17. The outlet side of the evaporator 18 is connected to the suction side of the compressor 10 via an accumulator 19.
[0021]
From the discharge side of the compressor 10 to the suction side of the compressor 10 via the cooling electromagnetic valve 13 → condenser 14 → liquid receiver 15 → thermal expansion valve 16 → check valve 17 → evaporator 18 → accumulator 19 The return closed circuit constitutes a normal cooling refrigeration cycle C.
[0022]
As is well known, the temperature type expansion valve 16 adjusts the valve opening (refrigerant flow rate) so that the superheat degree of the refrigerant at the outlet of the evaporator 18 is maintained at a predetermined value during normal refrigeration cycle operation (cooling mode). is there. The accumulator 19 separates the gas-liquid of the refrigerant, stores the liquid refrigerant, and sucks the gas refrigerant and a small amount of liquid refrigerant near the bottom (in which oil is dissolved) into the suction side of the compressor 10.
[0023]
On the other hand, a hot gas bypass passage 20 that bypasses the condenser 14 and the like is provided between the discharge side of the compressor 10 and the inlet side of the evaporator 18. The bypass passage 20 has a heating solenoid valve 21 and a throttle. 21a are provided in series. The throttle 21a serves as a heating depressurizing device, and can be constituted by a fixed throttle such as an orifice and a capillary tube.
[0024]
A closed circuit that returns from the discharge side of the compressor 10 to the suction side of the compressor 10 via the heating electromagnetic valve 21 → the throttle 21 a → the evaporator 18 → the accumulator 19 forms a hot gas heater cycle H for heating.
[0025]
The air conditioning case 22 of the vehicle air conditioner constitutes an air passage through which air flows toward the interior of the vehicle. Air is blown through the interior of the air conditioning case 22 by an electric air conditioning blower 23. The air-conditioning blower 23 is shown as an axial flow type for simplicity of illustration, but is actually a centrifugal blower having a centrifugal fan. This air conditioner blower 23 is driven to rotate by a blower motor 23a controlled by a blower drive circuit. Note that the amount of air blown by the blower 23 of the present embodiment can be switched continuously or stepwise by adjusting the blower control voltage applied to the blower motor 23a.
[0026]
On the suction side of the air-conditioning blower 23, an outside air suction port 70 for sucking outside air (outside air of the vehicle compartment), an inside air suction port 71 for sucking inside air (inside air of the vehicle interior), and an inside / outside air switching door 72 are provided. Have been. The inside / outside air switching door 72 constitutes inside / outside air switching means, and is driven by an actuator such as a servo motor via a link mechanism (not shown). The inside / outside air switching door 72 switches at least between an outside air mode in which outside air is drawn in from the outside air suction port 70 and a inside air mode in which inside air is drawn in from the inside air suction port 71.
[0027]
The evaporator 18 is an indoor heat exchanger installed in the air conditioning case 22. In the cooling mode, the refrigerant is circulated by the cooling refrigeration cycle C, and the low-pressure gas-liquid two-phase refrigerant flows into the evaporator 18. The air blown by the air-conditioning blower 23 is cooled by refrigerant evaporation (heat absorption) in the evaporator 18. In the heating mode, high-temperature refrigerant gas (hot gas) from the hot gas bypass passage 20 flows into the evaporator 18 and radiates heat to the air, so that the evaporator 18 functions as a radiator.
[0028]
In the air-conditioning case 22, a drain port 22a for draining condensed water generated in the evaporator 18 is provided below the evaporator 18, and the condensed water passes through a drain pipe (not shown) connected to the drain port 22a. Drained outside.
[0029]
In the air-conditioning case 22, a hot-water heating heat exchanger 24 that heats blast air using hot water (engine cooling water) from the vehicle engine 12 as a heat source is installed downstream of the evaporator 18 in the air. The hot water circuit to the heating heat exchanger 24 is provided with a hot water valve 25 for controlling the flow of hot water.
[0030]
By the way, the hot water heating heat exchanger 24 serves as a main heating means for heating the interior of the vehicle, whereas an evaporator (indoor heat exchanger) serving as a radiator by the hot gas heater cycle H is used. ) 18 constitutes auxiliary heating means.
[0031]
On the other hand, a defroster (DEF) outlet 31 for blowing out conditioned air (mainly hot air) toward the inner surface of the vehicle windshield, and a face (upper body) of the occupant, on the most downstream side of the air conditioning case 22. (FACE) outlet 32 for blowing out conditioned air (mainly cool air) toward the foot, and foot (FOOT) blowing for blowing out conditioned air (mainly hot air) toward the foot (lower body) of the occupant An outlet 33 is provided.
[0032]
Further, a plurality of outlet mode switching doors 34 to 36 for selectively opening and closing these outlets 31 to 33 are provided rotatably. The blow mode switching doors 34 to 36 constitute blow mode switching means, and are driven by an actuator such as a servomotor via a link mechanism (not shown).
[0033]
The air-conditioning electronic control unit (hereinafter referred to as ECU) 26 includes a microcomputer and its peripheral circuits, performs predetermined arithmetic processing in accordance with a preset program, opens and closes the solenoid valves 13 and 21, and performs other electric devices ( 11, 14a, 23, 25, etc.).
[0034]
FIG. 2 is an electric control block diagram of the first embodiment. In the ECU 26, a water temperature sensor 27a of the vehicle engine 12, an outside air temperature sensor 27b, a blowout air temperature sensor 27c of the evaporator 18, and a high pressure of the compressor discharge side are provided. Detection signals are input from a sensor group such as a refrigerant pressure sensor 27d to detect, an internal temperature sensor 27e, and a solar radiation sensor 27f to detect the amount of solar radiation into the vehicle interior.
[0035]
Further, operation signals of the following operation switches are input to the ECU 26 from the air conditioning operation panel 28 installed near the instrument panel in the vehicle compartment. That is, the air conditioner switch 29a is for instructing start or stop of the compressor 10 of the refrigeration cycle, and constitutes a cooling command means for issuing a command signal for setting a cooling mode. The hot gas switch 29b constitutes a hot gas heating command means for issuing a command signal for setting a heating mode by the hot gas heater cycle H.
[0036]
Further, on the air-conditioning operation panel 28, a blow-off mode changeover switch 29c for switching the air-conditioning blow-off mode, a temperature setting switch (temperature setting means) 29d for setting the temperature in the vehicle interior to a desired temperature, on / off of the blower 23, and air volume A blower switch 29e for instructing switching, an inside / outside air switching switch 29f for instructing switching between the outside air mode and the inside air mode, and the like are provided.
[0037]
Next, the operation of the present embodiment in the above configuration will be described. First, the operation of the refrigeration cycle will be described. When the air conditioner switch 29a is turned on and the cooling mode is set, the cooling solenoid valve 13 is opened by the ECU 26 and the heating solenoid valve 21 is closed. It is said. Accordingly, when the electromagnetic clutch 11 is connected and the compressor 10 is driven by the vehicle engine 12, the gas refrigerant discharged from the compressor 10 flows into the condenser 14 through the cooling electromagnetic valve 13 in the open state. .
[0038]
In the condenser 14, the refrigerant is cooled and condensed by the outside air blown by the cooling fan 14a. Then, the refrigerant after passing through the condenser 14 is gas-liquid separated by the liquid receiver 15, and only the liquid refrigerant is depressurized by the temperature type expansion valve 16 to be in a low-temperature low-pressure gas-liquid two-phase state.
[0039]
Next, the low-pressure refrigerant passes through the check valve 17 and flows into the evaporator 18 to absorb heat from the conditioned air blown by the blower 23 and evaporate. The conditioned air cooled by the evaporator 18 is blown into the vehicle interior from the face outlet 32 or the like to cool the vehicle interior. The gas refrigerant evaporated by the evaporator 18 is sucked into the compressor 10 via the accumulator 19 and compressed.
[0040]
When the hot gas switch 29b is turned on in winter and the heating mode by the hot gas heater cycle H is set, the cooling electromagnetic valve 13 is closed by the ECU 26, the heating electromagnetic valve 21 is opened, and the hot gas bypass is performed. The passage 20 opens. Therefore, the high-temperature discharge gas refrigerant (superheated gas refrigerant) of the compressor 10 passes through the heating electromagnetic valve 21 in the open state, is decompressed by the throttle 21a, and then flows into the evaporator 18. That is, the superheated gas refrigerant (hot gas) from the compressor 10 is directly introduced into the evaporator 18 by bypassing the condenser 14 and the like.
[0041]
At this time, the check valve 17 prevents the gas refrigerant from the hot gas bypass passage 20 from flowing toward the temperature type expansion valve 16. Therefore, the refrigeration cycle is operated in a closed circuit (hot gas heater cycle H) that returns to the discharge side of the compressor 10, the heating solenoid valve 21, the throttle 21a, the evaporator 18, the accumulator 19, and the suction side of the compressor 10. .
[0042]
Then, the superheated gas refrigerant that has been depressurized by the throttle 21a radiates heat to the blown air in the evaporator 18, and heats the blown air. Here, the amount of heat released from the gas refrigerant in the evaporator 18 corresponds to the compression work of the compressor 10. The gas refrigerant radiated by the evaporator 18 is drawn into the compressor 10 via the accumulator 19 and compressed.
[0043]
When the temperature of the hot water is low, such as immediately after the start of the engine 12 in cold weather, the air-conditioning blower 23 is maintained in a stopped state, and after the warm water rises to a predetermined temperature, the air-conditioning blower 23 is started with a low air flow. Is warmed up. By flowing hot water through the hot water type heating heat exchanger 24 via the hot water valve 25, the blast air heated by the evaporator 18 can be further heated in the heat exchanger 24. Therefore, even in cold weather, hot air having a higher temperature, which has been heated by both the evaporator 18 and the hot-water heating heat exchanger 24, can be blown into the vehicle interior.
[0044]
Next, the operation control of the hot gas heating mode according to the first embodiment will be described with reference to FIG. FIG. 3 shows a control routine executed by the ECU 26, which is started, for example, by turning on an ignition switch (not shown) of the vehicle engine 12. Then, in step S10, operation signals of the switch groups 29a to 29f of the air conditioning operation panel 28 are read, and in step S20, detection signals of the sensor groups 27a to 27f are read.
[0045]
Next, in step S30, it is determined whether the hot gas switch 29b of the air conditioning operation panel 28 is turned on (ON). If the hot gas switch 29b is on (ON), the process proceeds to step S40, and the inside / outside air switching door is switched. It is determined whether the suction mode switched and set by 72 is the outside air mode.
[0046]
When the suction mode is the outside air mode, the process proceeds to step S50, and the heating mode by the hot gas heater cycle H is started. That is, the heating electromagnetic valve 21 is opened, the cooling electromagnetic valve 13 is closed, and the electromagnetic clutch 11 is connected (ON) to operate the compressor 10. Thus, the heating mode using the hot gas heater cycle H is activated, and the above-described auxiliary heating function using the hot gas can be exhibited.
[0047]
On the other hand, when the suction mode is the inside air mode, the process returns from step S40 to step S10, and the heating mode by the hot gas heater cycle H is not started. That is, in the inside air mode, the activation of the hot gas heater cycle H is prohibited, so that it is possible to prevent the high-humidity inside air temperature from blowing out to the inner surface of the window glass of the vehicle. Therefore, it is possible to prevent the fogging of the window glass due to the blowing of the high-humidity internal temperature wind at the time of low outside temperature in winter.
[0048]
Further, during the operation of the hot gas heater cycle H, the cycle high pressure is detected by the refrigerant pressure sensor 27d, and when the high pressure increases to a first predetermined value or more, the electromagnetic clutch 11 is disengaged to stop the compressor 10. When the high pressure falls below a second predetermined value that is smaller than the first predetermined value by a predetermined amount, the performance control is performed such that the electromagnetic clutch 11 is connected and the compressor 10 is restarted.
[0049]
When performing the compression function force control, if the suction mode of the vehicle air conditioner is set to the inside air mode, the amount of heat radiation in the evaporator 18 decreases, and the rising speed of the high pressure increases faster than in the outside air mode. Therefore, the frequency of intermittent operation of the compressor increases, and the discomfort such as shock and noise due to the intermittent operation of the compressor increases. However, according to the present embodiment, the activation of the hot gas heater cycle H is prohibited in the inside air mode. Thus, the above-mentioned discomfort can be avoided.
[0050]
(2nd Embodiment)
In the first embodiment, when the suction mode is the inside air mode, the activation of the hot gas heater cycle H is prohibited. However, in the second embodiment, as shown in FIG. 4, the inside air mode is determined in step S40. If so, the process proceeds to step S60, and the outside air mode is forcibly set as the suction mode. Thereafter, the hot gas heater cycle H is started in step S50.
[0051]
Thereby, even when the suction mode is set to the inside air mode, the hot gas heater cycle H can be started by forcibly setting the outside air mode, so that the troubles associated with the inside air mode can be avoided, and the same as in the first embodiment. Functions and effects can be exhibited.
[0052]
(Other embodiments)
In the first embodiment, when the suction mode is the inside air mode, the process returns from step S40 to step S10, and the activation of the hot gas heater cycle H is prohibited. However, the activation of the hot gas heater cycle H by the inside air mode setting is prohibited. The prohibited state may be displayed by an appropriate display means.
[0053]
Further, in the first embodiment, a case has been described where a fixed displacement compressor is used as the compressor 10 and the operation of the compressor 10 is intermittently performed to control the capacity of the compressor 10. Of the compressor 10 may be controlled by using a variable displacement compressor capable of continuously or stepwise changing the pressure of the compressor 10 by controlling the displacement of the compressor.
[0054]
When a variable displacement compressor capable of changing the discharge capacity from 100% capacity to about 0% capacity is used as the compressor 10, the electromagnetic clutch 11 can be omitted. When the electromagnetic clutch 11 is abolished, in step S50, instead of the control output for connecting (ON) the electromagnetic clutch 11, a control output for setting the discharge displacement of the variable displacement compressor to a predetermined displacement is output. What should I do?
[0055]
In the first and second embodiments, the hot gas heating command means is constituted by the manually operated hot gas switch 29b. However, the amount of air heating by the heater core 24 is adjusted to adjust the temperature of the air blown into the vehicle interior. A maximum heating determining means for determining a maximum heating state of the temperature adjusting means may be provided, and the maximum heating determining means may constitute a hot gas heating command means, and may issue a hot gas heating mode setting command signal at the time of maximum heating. . The temperature adjusting means is, as is well known, an air mix door (not shown) for adjusting an air volume ratio between hot air passing through the heater core 24 and cold air bypassing the heater core 24, or a flow rate of hot water circulating through the heater core 24. Alternatively, it can be constituted by a hot water control valve 25 for adjusting the temperature.
[Brief description of the drawings]
FIG. 1 is an overall system configuration diagram showing a first embodiment of the present invention.
FIG. 2 is a block diagram of an electric control unit according to the first embodiment.
FIG. 3 is a control flowchart of the first embodiment.
FIG. 4 is a control flowchart of a second embodiment.
[Explanation of symbols]
10 compressor, 18 evaporator (indoor heat exchanger),
20 hot gas bypass passage, 21a pressure reducing device for heating,
72 ... inside / outside air switching door (inside / outside air switching means).

Claims (4)

Inside / outside air switching means (72) for switching and introducing inside air and outside air;
An indoor heat exchanger (18) for exchanging heat with the air switched and introduced by the inside / outside air switching means (72);
A compressor (10) for circulating a refrigerant through a refrigeration cycle having the indoor heat exchanger (18);
A hot gas bypass passage (20) for reducing the pressure of the gas refrigerant discharged from the compressor (10) and introducing it to the indoor heat exchanger (18);
A hot gas heater that operates the indoor heat exchanger (18) as a radiator by introducing a refrigerant discharged from the compressor (10) into the indoor heat exchanger (18) through the hot gas bypass passage (20). In a vehicle air conditioner that sets a cycle (H),
It is determined whether the suction mode set by the inside / outside air switching means (72) is the outside air mode,
An air conditioner for a vehicle, wherein the heating mode is executed by the hot gas heater cycle (H) when the suction mode is the outside air mode. Only when the suction mode is the outside air mode, the heating mode by the hot gas heater cycle (H) is executed. When the suction mode is the inside air mode, the execution of the heating mode by the hot gas heater cycle (H) is prohibited. The refrigeration cycle apparatus according to claim 1, wherein: The refrigeration cycle apparatus according to claim 1, wherein when the suction mode is the inside air mode, after switching the suction mode to the outside air mode, the heating mode by the hot gas heater cycle (H) is executed. A hot gas heating command means (29b) for issuing a command signal of a heating mode by the hot gas heater cycle (H);
The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the suction mode is determined when the command signal is output.

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