JP2003291623A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for vehicles displaying effective quick heating ability independent of the valve opening property of an expansion valve. <P>SOLUTION: This air conditioner is provided with an electric heater 41, which can heat the refrigerant (compressor suction refrigerant) at an outlet, a pressure and temperature detecting sensor 42 for detecting a degree SH of over heat of the refrigerant at the evaporator outlet and a control means 43 for controlling the calory coming from the electric heater 41 based on the detection result so that the refrigerant at the evaporator outlet becomes a specified degree SH of over heat. By this constitution, this air conditioner has excellent quick heating ability, and the compressor suction refrigerant returns to a compressor 2 with a certain degree of proper over heat regardless of the valve opening property TXV of the expansion valve 6 and a heat load at an evaporator 7, both of cooling performance and heating performance can be reconciled with each other. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner for adjusting a temperature environment inside a vehicle.

[0002]

2. Description of the Related Art An air conditioner for a vehicle of this type includes an evaporator as an endothermic vehicle heat exchanger for heat absorption, which is incorporated into a refrigerant cycle in an air channel of a vehicle compartment into which inside and outside air is introduced.
And a heater core as a radiator incorporated in the hot water line, wherein the evaporator absorbs heat from the air in the vehicle interior air flow path to generate cool air, and the heater core heats the air in the vehicle interior air flow path. By doing so, warm air is generated, and the temperature inside the vehicle compartment is adjusted by adjusting the ratio of these cold air and hot air by the air mix door.

The refrigerant that has absorbed heat by the evaporator and evaporated is compressed by the compressor driven by the engine and discharged toward the main condenser as an exterior heat exchanger of the vehicle, where it is radiated and condensed by the main condenser. It is expanded by an expansion valve as expansion means and flows into the evaporator.

By the way, in such a vehicle air conditioner, since the engine cooling water is used as a heat medium to generate hot air, the temperature of the engine cooling water is changed immediately after the engine is started or when the traveling load is small. When the temperature is not so high, there is a problem that the temperature inside the vehicle compartment cannot be quickly raised.

In view of these problems, Japanese Unexamined Patent Publication No. 9-1
In the vehicle air conditioners disclosed in Japanese Patent No. 75140 and Japanese Patent Laid-Open No. 10-44742, a sub-condenser as a heat radiating vehicle interior heat exchanger is arranged in the vehicle interior air flow path, and refrigerant is discharged during heating operation. The main condenser is bypassed and circulated between the sub condenser, the expansion valve, the evaporator, and the compressor, and the sub condenser radiates heat to the air flowing in the air passage in the vehicle interior. As a result, in addition to the heater core that uses the engine cooling water as the heat medium, warm air is also generated by the sub-condenser that uses the refrigerant as the heat medium. Even when the temperature is not sufficiently high, the temperature in the vehicle compartment can be raised relatively quickly.

In a vehicle air conditioner equipped with this type of sub-capacitor, a sub-evaporator for exchanging heat with the engine cooling water is arranged in the low-pressure side pipe in order to further increase the amount of heat radiation from the sub-capacitor immediately after the engine is started. Some do. Note that the conventional example includes an example in which the amount of intake of the inside air is increased immediately after the engine is started to increase the heat load on the evaporator.

[0007]

However, in the vehicle air conditioner, the valve opening characteristic TXV of the expansion valve is appropriately set in advance (generally, it is set in accordance with the cooling operation), and the compressor suction refrigerant (evaporator outlet refrigerant) is set. Is returned with an appropriate degree of superheat (superheat SH). Therefore, in the structure in which the heat of the engine cooling water is simply given by the sub-evaporator as in the above-mentioned conventional technique, the compressor suction is performed according to the temperature of the engine cooling water. The degree of superheat of the refrigerant may become too high or too low, which may rather reduce the performance of the refrigerant cycle.

The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle air conditioner capable of exhibiting effective quick heating performance regardless of the valve opening characteristics of the expansion valve. is there.

[0009]

To achieve the above object, in the invention according to claim 1, a radiator for radiating the heat of the vehicle drive system cooling water to the air blown into the vehicle interior, A heat radiation vehicle interior heat exchanger that radiates the heat of the compressed gaseous refrigerant to the air blown into the vehicle compartment to condense the refrigerant, and expands the refrigerant condensed in the heat radiation vehicle interior heat exchanger An expansion means, an endothermic passenger compartment heat exchanger for evaporating the refrigerant by causing the refrigerant expanded by the expansion means to absorb the heat of the air in the passenger compartment, and an evaporator driven by the engine to evaporate in the endothermic passenger compartment heat exchanger. In a dual-purpose air conditioner comprising a compressor that compresses the discharged refrigerant and discharges it toward the heat dissipation vehicle interior heat exchanger, a refrigerant heating means capable of heating the outlet refrigerant of the heat absorption vehicle interior heat exchanger, , Outlet cooling of the heat absorption vehicle interior heat exchanger Superheat degree detecting means for detecting the superheat degree of, and a control means for controlling the amount of heat from the refrigerant heating means so that the outlet refrigerant of the heat absorption vehicle interior heat exchanger based on the detection result has a predetermined superheat degree, It is characterized by including.

According to a second aspect of the invention, the refrigerant heating means is heat of vehicle drive system cooling water.

According to a third aspect of the invention, the refrigerant heating means is an electric heater.

According to another aspect of the present invention, the predetermined superheat degree is inclined with a lower limit curve of the superheat degree which gradually rises as the pressure rises, and a gradient higher than the lower limit curve of the superheat degree. And an upper limit curve, and at least the upper limit curve is 20 ° C. or lower.

[0013]

According to the first aspect of the present invention, the refrigerant heating means capable of heating the outlet refrigerant of the heat absorbing vehicle interior heat exchanger and the superheat degree of the outlet refrigerant of the heat absorbing vehicle interior heat exchanger are controlled. Superheat detection means for detecting, and a control means for controlling the amount of heat from the refrigerant heating means so that the outlet refrigerant of the heat absorption vehicle interior heat exchanger has a predetermined superheat based on the detection result, Because of the characteristics, the heat load of the refrigerant cycle can be increased by the refrigerant heating means, and it is possible to provide the vehicle air conditioner having extremely excellent rapid heating performance. Moreover, since the control means controls the temperature at the evaporator outlet refrigerant to a predetermined degree of superheat, rapid heating can be effectively exhibited regardless of the valve opening characteristic TXV of the expansion valve.

According to the second aspect of the present invention, since the refrigerant heating means is heat of the vehicle drive system cooling water, a new heat source is not prepared at a relatively low cost. The invention can be embodied.

According to the third aspect of the invention, the refrigerant heating means is an electric heater.
Unlike the described invention, the controllability is excellent without being influenced by the driving load of the vehicle.

According to the fourth aspect of the present invention, when the refrigerant pressure at the outlet of the evaporator is low, the superheat degree of the refrigerant at the outlet of the evaporator is lowered to increase the discharge pressure of the compressor so that a sufficient refrigerant circulation amount can be secured early. On the other hand, when the evaporator outlet refrigerant pressure Pe is high, that is, when the circulating refrigerant amount is sufficient, the compressor power can be suppressed by increasing the degree of superheat of the evaporator outlet refrigerant. Moreover, since the upper limit of the superheat degree SH of the evaporator outlet refrigerant is regulated to 20 ° C. or less, it is possible to prevent the compressor body from overheating, and it is possible to realize a very well-balanced rapid heating operation.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a vehicle air conditioner 1 according to a first embodiment of the present invention. The vehicle air conditioner 1 includes a refrigerant cycle in which a refrigerant is circulated to perform heat exchange between the refrigerant and air, and an engine cooling water heated by exhaust heat of an engine is circulated to circulate the engine cooling water and air. It is equipped with a hot water line that exchanges heat between them.

The refrigerant cycle consists of a compressor 2, a main condenser 3, a sub condenser 4 as a heat radiating passenger compartment heat exchanger, a liquid tank 5, an expansion valve 6 as an expanding means, and a heat absorbing passenger compartment heat exchange. The evaporator 7 as a container is connected through a piping member so that the refrigerant given kinetic energy by the compressor 2 circulates between them.

The compressor 2 is arranged outside the vehicle compartment such as an engine room, and compresses the sucked low-pressure gaseous refrigerant and discharges it as high-pressure gaseous refrigerant. The compressor 2 is driven, for example, by transmitting the power of the crankshaft of the engine 10 via the compressor clutch 8. The compressor 2 is of a swash plate type, and the tilt of the swash plate can be controlled from the outside by an electric signal.

That is, although not shown, the compressor 2 has an electronically operated control valve (ECV) such as a solenoid valve which can be externally controlled by an electric signal. For example, when a solenoid valve that communicates with the high pressure side is used as the ECV, the inside of the crankcase and the low pressure side communicate with each other through a passage of a predetermined opening, and the pressure inside the crankcase escapes to the low pressure side. Has become. Therefore, the solenoid valve
By controlling the pressure in the crankcase by turning on / off the high-side pressure by turning on / off the N / OFF, the balance of the pressure applied to the piston is changed and the inclination of the swash plate is changed. The capacity can be controlled.

At this time, a duty signal having a proper duty ratio is given to the solenoid valve as an electric signal from the outside by a control unit for controlling the operation of the entire vehicle air conditioner 1. When it is necessary to reduce the capacity, give a duty signal with a large duty ratio to lengthen the opening time of the solenoid valve to increase the pressure in the crankcase and increase the capacity. A duty signal having a small duty ratio is given to shorten the valve opening time of the solenoid valve and reduce the pressure in the crankcase.

The main condenser 3 is arranged outside the vehicle compartment and radiates the heat of the high temperature and high pressure gaseous refrigerant discharged from the compressor 2 to the outside air. Outside air is blown to the main condenser 3 by driving a blower 11 such as an electric fan. The main condenser 3 includes a high-temperature high-pressure gaseous refrigerant passing through the main condenser 3 and the main condenser 3
By causing heat exchange with the outside air blown onto the
The heat of the high temperature and high pressure gaseous refrigerant is radiated to the outside air.

The sub-condenser 4 is arranged in the vehicle interior air flow passage P1 described later, and radiates the heat of the high-temperature high-pressure gaseous refrigerant discharged from the compressor 2 to the air flowing in the vehicle interior air flow passage P1. It is a thing. Vehicle interior air flow path P1
The air flowing inside absorbs the heat of the refrigerant radiated by the sub-condenser 4 to become warm air and flows to the downstream side of the vehicle interior air flow path P1.

In the vehicle air conditioner 1, the main condenser 3 and the sub condenser 4 are connected in parallel, and the main condenser 3 and the sub condenser 4 are selectively used. . That is, the flow path through which the refrigerant discharged from the compressor 2 flows is divided into a first refrigerant line L1 passing through the main condenser 3 and a second refrigerant line L2 passing through the sub condenser 4 via the three-way connector 12. It is branched. Then, in the preceding stage of the liquid tank 5, the first refrigerant line L1 and the second refrigerant line L2 are connected to the three-way connector 13
It is designed to meet via. The reference numeral 9 is
The sensor 9 is interposed between the three-way connector 12 and the compressor 2 and detects the pressure of the refrigerant discharged from the compressor 2.

In the first refrigerant line L1, an electromagnetic valve 14 is provided in the front stage of the main condenser 3, and a check valve 15 is provided in the rear stage of the main condenser 3. Similarly, in the second refrigerant line L2 as well, a solenoid valve 16 is provided in the front stage of the sub-condenser 4 and a check valve 17 is provided in the rear stage of the sub-condenser 4. Then, the first refrigerant line L1
The opening / closing state of the electromagnetic valve 14 provided in the first refrigerant line L2 and the opening / closing state of the electromagnetic valve 16 provided in the second refrigerant line L2 are switched by the control unit.
The first or second refrigerant line L2 is selected.

Specifically, during the cooling operation, the control unit sets the electromagnetic valve 14 provided in the first refrigerant line L1 to "open" and the electromagnetic valve provided in the second refrigerant line L2. Set valve 16 to "closed". This makes the first
The refrigerant line L1 is selected, and the refrigerant discharged from the compressor 2 is supplied to the main condenser 3. On the other hand, during the heating operation, the control unit sets the solenoid valve 14 provided in the first refrigerant line L1 to “close” and the solenoid valve 16 provided in the second refrigerant line L2 to “open”. Set to. As a result, the second refrigerant line L2 is selected and the refrigerant projected from the compressor 2 is supplied to the sub-condenser 4.

As described above, in the vehicle air conditioner 1, the control unit includes the first refrigerant line L1 and the second refrigerant line L1.
Functioning as a switching means for selectively switching between the refrigerant line L2 and the refrigerant line L2, the flow path of the refrigerant discharged from the compressor 2 is switched between the cooling operation and the heating operation, and the main condenser 3 and the sub-condenser 4 are selected. It has been used for various purposes.

The liquid tank 5 includes the main condenser 3
Alternatively, the liquefied refrigerant, which has a low temperature when radiated by the sub-capacitor 4, is temporarily stored. The liquid tank 5 is provided with a dust filter and also has a function of removing dust mixed in the stored liquid refrigerant. It is desirable that the liquid tank 5 is disposed at the rear stage of the three-way connector 13, but if it is difficult to dispose at the rear stage of the three-way connector 13 due to the restriction of the piping layout in the engine room, As indicated by a broken line in FIG. 1, it may be arranged immediately after the main capacitor 3 or integrally with the main capacitor 3. In this case, the liquefied refrigerant that is radiated by the sub-capacitor 4 is directly supplied to the expansion valve 6 without passing through the liquid tank 5.

The expansion valve 6 rapidly expands the liquid refrigerant that is radiated by the main condenser 3 or the sub-condenser 4 and temporarily stored in the liquid tank 5, so that the evaporator 7 as a low-temperature low-pressure atomized refrigerant is supplied to the evaporator 7. To supply.

The evaporator 7 is arranged in the vehicle interior air flow path P1 upstream of the sub-condenser 4, and heats the air flowing in the vehicle interior air flow path P1 at a low temperature and low pressure supplied from the expansion valve 6. The mist-like refrigerant is endothermic.

The refrigerant supplied to the evaporator 7 in the form of a low-temperature low-pressure mist by the expansion valve 6 deprives the heat of the air flowing in the vehicle interior air flow path P1 and vaporizes when passing through the evaporator 7. Then, this gaseous refrigerant is sucked into the compressor 2, compressed again, and discharged. On the other hand, the air absorbed by the refrigerant in the evaporator 7 is dehumidified and becomes cold air, and flows to the downstream side of the vehicle interior air flow path P1. Reference numeral 18 is a sensor that is arranged in the vicinity of the air outlet of the evaporator 7 and detects the temperature of the air that has passed through the evaporator 7.

In the refrigerant cycle, the refrigerant is circulated as described above, and heat is exchanged in the main condenser 3, the sub condenser 4, and the evaporator 7 to generate hot air or cold air in the vehicle interior air flow path P1. I am trying.

The hot water line circulates the engine cooling water to perform heat exchange using the engine cooling water that has become hot due to the exhaust heat of the engine 10, and incorporates the heater core 21 as a radiator. ing.

The heater core 21, together with the sub-condenser 4, is arranged downstream of the evaporator 7 in the vehicle interior air flow path P1, and is the cooling water supplied from the water jacket of the engine 10 through the piping member, that is, The engine cooling water, which has been heated to a high temperature by the exhaust heat of the engine, is used as a heat medium to dissipate heat by the retained heat of the engine cooling water. In addition to the heat of the refrigerant radiated by the sub-condenser 4 described above, the air flowing in the vehicle interior air flow path P1
The heat from the heater core 21 is absorbed. As a result, warm air is effectively generated in the vehicle interior air flow path P1.

A water valve 22 is provided in a piping member for supplying engine cooling water from the water jacket of the engine 10 to the heater core 21, and the water valve 22 is adjusted by the control unit described above. The flow rate of engine cooling water supplied to the heater core 21, that is, the heat radiation amount of the heater core 21 is adjusted.

A blower fan 31 is provided on the upstream side of the vehicle interior air flow path P1. By driving the blower fan 31, outside air is introduced into the vehicle interior air flow path P1 from the outside air introduction port, or inside air is introduced into the vehicle interior air flow path P1 from the inside air introduction port. An intake door 32 as an inside / outside air adjusting means is provided in the vicinity of the outside air introducing port and the inside air introducing port.
Is controlled so that the ratio of the outside air and the inside air introduced into the vehicle interior air flow path P1 is adjusted.

The air introduced into the vehicle interior air flow path P1 from the outside air introduction port or the inside air introduction port first passes through the evaporator 7 arranged on the upstream side of the vehicle interior air flow path P1. At this time, as described above, the air passing through the evaporator 7 is dehumidified by being absorbed by the refrigerant in the evaporator 7, becomes cool air, and is made to flow downstream.

In the vehicle interior air flow path P1, the evaporator 7 is provided.
The downstream side of is divided into a warm air flow path R1 in which the heater core 21 and the sub-capacitor 4 are arranged, and a bypass flow path R2 that bypasses the heater core 21 and the sub-capacitor 4. As described above, the air that has flowed through the warm air flow path R1 absorbs heat from the heater core 21 when passing through the heater core 21, and from the refrigerant inside the sub-condenser 4 when passing through the sub-condenser 4. The radiated heat is absorbed and becomes warm air, which is then flowed to the downstream side. On the other hand, the bypass flow path R2
The air that has been made to flow into the evaporator 7 will be made to flow to the downstream side in the state of being the cold air that has been absorbed by the refrigerant inside the evaporator 7.

Here, at the branch point where the warm air flow passage R1 and the bypass flow passage R2 are branched, the ratio of the flow rate of air flowing through the warm air flow passage R1 to the flow rate of air flowing through the bypass flow passage R2 is set. An air mix door 33 for adjusting is provided.
Then, the air mix door 33 is drive-controlled to adjust the ratio between the flow rate of the air flowing through the warm air flow path R1 and the flow rate of the air flowing through the bypass flow path R2, so that the defroster outlet is finally opened. The temperature of the air blown from the vents, vents and foot vents is adjusted.

An air mix for mixing the warm air from the warm air flow passage R1 and the cold air from the bypass flow passage R2 on the further downstream side of the warm air flow passage R1 and the bypass flow passage R2 of the vehicle interior air flow passage P1. A chamber 34 is provided. Then, in the air mix chamber 34, a defroster outlet for blowing out temperature-controlled air obtained by mixing warm air and cold air toward the windshield, and a vent outlet for blowing out toward the upper half of the occupant's upper body. , Foot outlets are provided to blow out toward the feet of the passengers.
A defroster door 35, a vent door 36, and a foot door 37 are provided near each air outlet,
By controlling the drive of these doors, the flow rate of the air blown from each of the air outlets is adjusted.

The vehicle air conditioner 1 constructed as described above
In the above, since the air dehumidified by passing through the evaporator 7 is heated by the heater core 21 and the sub-condenser 4 to generate warm air, dehumidification can be performed during the heating operation.

Further, in this vehicle air conditioner 1,
Since the sub-capacitor 4, which is a heat-radiating passenger compartment heat exchanger, is arranged in the passenger compartment air flow path P1 so that not only the heater core 21 but also the sub-condenser 4 generates hot air, engine cooling water is generated. Even if the temperature is not sufficiently high, the temperature in the vehicle compartment can be raised relatively quickly. In order to save power, when the engine cooling water reaches a predetermined temperature, the compressor clutch 8 is turned off and only the heater core 21 is heated.

In the vehicle air conditioner 1, the refrigerant flowing through the low-pressure side pipe, that is, the evaporator outlet refrigerant (≈), is used so that the sub-condenser 4 can be used more effectively during heating.
The electric heater 41 as "refrigerant heating means" for heating the compressor suction refrigerant), the pressure temperature sensor 42 as superheat detection means for detecting the superheat degree SH of the evaporator outlet refrigerant, and the evaporator outlet based on the detection result. The electric heater 41 so that the refrigerant has a predetermined superheat degree SH
And a control means 43 for controlling the heating amount of. The control means 43 is composed of a program stored in the memory of the control unit.

In FIG. 3, the horizontal axis represents the pressure of the evaporator outlet refrigerant and the vertical axis represents the superheat degree SH of the evaporator outlet refrigerant. The superheat degree SH of the evaporator outlet refrigerant obtained by the study of the applicant of the present invention is shown. It shows the appropriate range of.
The proper range of the superheat degree SH is a practical range of rapid heating operation (1.0 kg · cm2G ≦ refrigerant pressure Pe ≦ 2.5 kg ·
cm2G), the lower limit curve A of the superheat degree SH that gradually increases as the pressure increases, and the upper limit curve B that inclines with a slope larger than the upper limit curve of the superheat degree SH.
And the upper limit curve B is at least 20 ° C. or lower. Here, the superheat degree SH refers to a temperature based on the boiling temperature, and for example, the pressure in the refrigerant in this embodiment is 2 kg / cm 2.
Since the boiling temperature at G is 0 ° C, the refrigerant pressure is 2 kg.
The superheat of 1 ° C./cm 2 G means 1 ° C.

The reason why the lower limit curve A and the upper limit curve B gradually increase as the pressure rises is that the compressor superheat degree SH of the evaporator outlet refrigerant is reduced when the evaporator outlet refrigerant pressure Pe (Pc) is low. It is desirable to increase the discharge pressure Pd to ensure a sufficient amount of refrigerant circulation at an early stage. On the other hand, when the evaporator outlet refrigerant pressure Pe (Pc) is high, the compressor discharge pressure Pd is also high, so the amount of circulating refrigerant is rather large. This is because it is desired to suppress the compressor power by increasing the superheat degree SH of the evaporator outlet refrigerant. The reason why the upper limit of the superheat degree SH of the evaporator outlet refrigerant is specified to be 20 ° C. or lower is that the superheat degree SH is 20 degrees or less.
If the temperature exceeds ℃, it becomes difficult to cool the inside of the compressor 2 (crank chamber) and the main body of the compressor 2 overheats.

In this embodiment, the evaporator outlet refrigerant is heated by the electric heater 41 so that the evaporator outlet refrigerant falls within the proper range shown in FIG. FIG. 2 is a flowchart showing a control procedure of the electric heater by the control means 43.

First, in the normal heating operation, when the engine cooling water is below a predetermined temperature (for example, 70 ° C.) or when the quick heating operation switch is turned on, the compressor 2 is switched from the normal hot water heating operation. Clutch 8 is ON
Then, the rapid heating operation using the sub-capacitor 4 is started.

By the control not shown in the figure, when the rapid heating operation is started, or during the rapid heating operation, the ECV
If the operation permission state is not satisfied, it is determined that the heating operation precondition is not satisfied, the clutch 8 of the compressor 2 is turned off, and the heating operation is ended. This ECV
The operation permitted state is, for example, a case where the engine speed is equal to or lower than a predetermined value and the compressor discharge refrigerant pressure is equal to or lower than a predetermined value.

In this embodiment, when the rapid heating operation is started, the program of the control means 43 shown in FIG. 2 is started (S10).

When the program of the control means 43 is started (S10), the electric heater 41 is turned on (S20),
The output value is controlled in the following steps.

First, when the program of the control means 43 of the electric heater 41 starts (S10), the control means 43.
Turns on the electric heater 41 at the maximum output (S20), and the duty ratio of the electromagnetic control valve ECV of the compressor 2 is 7
It is judged whether it is 0% or more (S30).

If the ECV duty ratio is 70% or less, it is determined that the heat load of the refrigerant cycle is sufficiently high and the amount of circulating refrigerant is sufficient, and the electric heater 41 is turned off (S).
100), and shifts to normal heating operation (S110). On the other hand, if the ECV duty ratio is 70% or more, it is determined that the heat load of the refrigerant cycle is still low and the circulating refrigerant amount is not sufficient, and the superheat degree SH of the evaporator outlet refrigerant detected by the temperature / pressure sensor 42 is as shown in FIG. It is determined whether or not it is within the appropriate range shown in (S50).

If the superheat degree SH of the evaporator outlet refrigerant is within the proper range, the output value of the electric heater 41 is maintained (S
90). On the other hand, when the superheat degree SH of the evaporator outlet refrigerant is not within the proper range, it is determined whether it is above or below the proper range (S
50), if it is above the output value of the electric heater 41 is 5% DO
WN (S60), if lower, the output value of the electric heater 41 is calculated as 5% UP (S70). The output value of the electric heater 41 is changed based on this value (S80). This allows
The refrigerant always returns to the compressor 2 with an appropriate superheat degree SH.

After controlling the output value (heating amount) of the electric heater 41 in this manner, the process returns to S30 and the above-mentioned processing is repeated.

When the water temperature of the engine cooling water reaches a predetermined value (for example, 70 ° C.) or more during the rapid heating operation,
The electric heater 41 is turned off at the same time when the clutch 8 of the compressor 2 is turned off to start the normal hot water heating operation.

As described above, in the vehicle air conditioner 1 of this embodiment, the electric heater 41 can apply an appropriate heat load to the refrigerant cycle even when the heat load on the evaporator 7 is low immediately after the engine is started. Because it can be done, it is extremely excellent in rapid heating.

Moreover, the control means sets a predetermined superheat degree SH based on the temperature and pressure detection result of the evaporator outlet refrigerant.
Is controlled so that the valve opening characteristic TX of the expansion valve 6 is
Regardless of V, rapid heating can be effectively exhibited. In other words, while the expansion valve 6 is set in accordance with the cooling operation and the cooling performance is emphasized, the rapid heating performance using the sub-condenser 4 can be maintained high, so that it is excellent in both the cooling operation and the heating operation. Can be demonstrated.

Further, since the heat load of the refrigerant cycle depends on the heat quantity of the electric heater 41, it is not necessary to consider the heat load of the evaporator 7 as in the conventional case, and the degree of freedom of intake door control is eliminated. Spreads.

Further, according to the vehicle air conditioner 1 of this embodiment, since the refrigerant heating means is the electric heater, there is also an advantage that the controllability is excellent without being influenced by the driving load of the vehicle.

In the above embodiment, the radiator dissipates the heat of the engine cooling water to the air blown into the passenger compartment, but instead of this, the vehicle drive system cooling water other than the engine cooling water is used. For example, heat of cooling water for motors of electric vehicles, stack cooling water for fuel cell vehicles, or the like may be radiated.

In the above embodiment, the electric heater is used as the refrigerant heating means, but a glow plug may be inserted in the low pressure pipe, or the vehicle drive system cooling water downstream of the heater core may be circulated. It may be a sub-evaporator that heats the refrigerant at the outlet of the evaporator.
In this case, in order to make the amount of heat variable, a structure including a pump, a control valve, or the like that changes the flow rate of the drive system cooling water flowing through the sub-evaporator may be used.

Further, in the above embodiment, the clutch of the compressor is turned off to shift to the normal hot water heating, but instead of this, a control signal from the control unit minimizes the refrigerant discharge capacity of the compressor. Alternatively, the heat pump may not be substantially operated and only the radiator may be heated.

Although the proper range of the superheat degree SH is shown in the pressure-superheat degree graph shown in FIG. 3, it may be calculated directly from the pressure and temperature of the evaporator outlet refrigerant.

Besides, various modifications can be made to the above-described embodiment without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of an electric heater by a control means 43.

FIG. 3 is a pressure-superheat degree graph showing an appropriate range of the superheat degree SH of the outlet refrigerant of the evaporator 7.

[Explanation of symbols]

1 Vehicle air conditioner 2 compressor 4 Sub-capacitor (heat exchanger for heat dissipation inside the vehicle) 6 Expansion valve (expansion means) 7 Evaporator (heat exchanger for heat absorption inside passenger compartment) 21 Heater core (radiator) 41 Electric heater (refrigerant heating means) 42 Pressure temperature sensor (superheat detection means) 43 Control means

Claims (4)

[Claims] 1. A radiator (21) for radiating heat of cooling water of a vehicle drive system (10) to air blown into the vehicle compartment, and air blown out of heat of a compressed gaseous refrigerant into the vehicle cabin. A heat radiation vehicle interior heat exchanger (4) that radiates heat to condense the refrigerant, expansion means (6) that expands the refrigerant condensed in the heat radiation vehicle interior heat exchanger (4), and the expansion means ( 6)
An endothermic passenger compartment heat exchanger (7) for evaporating the refrigerant by absorbing the heat of the air in the passenger compartment with the refrigerant expanded by the above; and the endothermic passenger compartment heat exchanger (7) driven by an engine (10). A compressor (2) for compressing the refrigerant evaporated in step (1) and discharging it toward the heat dissipation vehicle interior heat exchanger (4);
A vehicle air conditioner (1) comprising: a refrigerant heating means (41) for heating an outlet refrigerant of the heat absorbing vehicle interior heat exchanger (7); and an outlet of the heat absorbing vehicle interior heat exchanger (7). A superheat degree detecting means (42) for detecting a superheat degree (SH) of the refrigerant, and based on the detection result, the outlet refrigerant of the heat absorption vehicle interior heat exchanger (7) has a predetermined superheat degree (SH). Control means (43) for controlling the amount of heat from the refrigerant heating means (41)
A vehicle air conditioner (1), comprising: 2. The vehicle air conditioner according to claim 1, wherein the refrigerant heating means is heat of vehicle drive system cooling water. 3. The vehicle air conditioner according to claim 1, wherein the refrigerant heating means is an electric heater. 4. The predetermined superheat degree is defined by a lower limit curve of the superheat degree that gradually increases as the pressure increases, and an upper limit curve that inclines with a gradient greater than the lower limit curve of the superheat degree. A vehicle air conditioner characterized by being in a range and having at least an upper limit curve of 20 ° C. or less.