JP3351064B2 - Heat pump type air conditioner for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner for a vehicle having a vapor compression cycle for circulating a refrigerant to a heat exchanger outside a vehicle compartment and a heat exchanger inside a vehicle compartment by driving a compressor.

[0002]

2. Description of the Related Art A conventional heat pump type air conditioner for a vehicle is disclosed in Japanese Unexamined Patent Publication No. Hei.
No. 808, for example. In this method, the flow of the refrigerant is reversed between a heating operation and a cooling operation by a four-way valve.During the heating operation, the heat exchanger outside the vehicle compartment is used as a heat absorber and the heat exchanger inside the vehicle interior is used as a radiator. ing. In the cooling operation, the heat exchanger outside the vehicle compartment is used as a radiator, and the heat exchanger inside the vehicle compartment is used as a heat absorber.

[0003] Specifically, Japanese Patent Application Laid-Open No. 2-290475
The cooling and heating device disclosed in Japanese Patent Laid-Open Publication No. H10-26511 will be described with reference to FIG.

[0004] That is, during the heating operation, the four-way valve 2 is switched as shown by the solid line, and the refrigerant flows from the compressor 1 → the four-way valve 2 → the first interior heat exchanger 3 → the heating heat exchanger 4 → the second.
It circulates through the heat exchanger 5 inside the vehicle, the expansion valve 6, the heat exchanger 7 outside the vehicle, the four-way valve 2, the receiver 8, and the compressor 1. The first vehicle interior heat exchanger 3 radiates heat of the high-temperature refrigerant discharged from the compressor 1 to the air introduced by the blower fan 9 to generate warm air for vehicle interior heating. The heating heat exchanger 4 absorbs waste heat from the engine 10 into a refrigerant, and the second vehicle interior heat exchanger 5 radiates the heat of the refrigerant to the air introduced by the blower fan 11 to heat the vehicle interior. Make warm air. The exterior heat exchanger 7 absorbs the heat of the outside air introduced by the fan 12 into the refrigerant.

During the cooling operation, the four-way valve 2 is switched as shown by the dotted line, and the refrigerant flows from the compressor 1 → the heat exchanger 7 outside the vehicle → the expansion valve 6 → the heat exchanger 5 in the second vehicle interior → the heat exchanger 5 in the first vehicle interior. It circulates in the order of heat exchanger 3 → four-way valve 2 → receiver 8 → compressor 1. The exterior heat exchanger 7 is a compressor 1
The heat of the high-temperature refrigerant discharged from the radiator is radiated to the outside air, and the first and second interior heat exchangers 3 and 5 are blower fans 9 and 11.
The heat of the introduced air is radiated to the refrigerant to produce cold air for cooling the vehicle interior.

In the conventional example, the flow of the refrigerant is reversed by the four-way valve 2 during the heating operation and the cooling operation. During the heating operation, the exterior heat exchanger 7 is used as a heat absorber, and the interior heat exchangers 3 and 5 are used as radiators. During the cooling operation, the outside heat exchanger 7 is used as a radiator, and the inside heat exchangers 3, 5 are used as heat absorbers. Therefore, when the heating operation is performed particularly when the outside air temperature is low, the amount of heat absorbed in the vehicle exterior heat exchanger 7 decreases. For this reason, assuming that the work of the compressor 1 is constant, the heat release in the vehicle interior heat exchangers 3 and 5, which dissipates the total amount of heat absorbed by the external heat exchanger 7 and the work of the compressor 1, is performed. The amount of heat decreases and the heating capacity decreases. In addition, under climatic conditions such as rainfall and snowfall, frost formation is likely to occur, and the number of times of defrosting operation may increase, so that stable heating operation may not be obtained.

Further, since the length of the refrigerant flow path does not change between the cooling operation and the heating operation, it is not necessary to adjust the amount of the working refrigerant between the cooling operation and the heating operation. Therefore, it is necessary to change the pipe diameter and the like of each of the pipes on the heat exchanger 7 outside the vehicle compartment and the heat exchangers 3 and 5 on the vehicle compartment so as to withstand high temperature and high pressure.

Furthermore, during the heating operation, since waste heat from the engine 10 is absorbed to generate warm air for heating the vehicle interior, it is not suitable for a vehicle having no large heat source such as a solar car or an electric car. .

Further, in order to secure the window clearness required for a vehicle heating device, a cooling operation is performed instead of a heating operation.
After the air-conditioning air is once cooled in the vehicle interior heat exchangers 3 and 5, it is necessary to further reheat the air. However, as in electric vehicles, when waste heat from an engine or the like cannot be obtained and a sufficient reheat heat source cannot be supplied, the heating capacity may be insufficient, and the heating performance may not be ensured or may be insufficient. there were. It is also possible to reheat by providing another heat source such as an electric heater, but there is a problem that a large amount of power consumption is required to secure a sufficient heating capacity.

On the other hand, the applicant of the present invention has disclosed in
No. 9333 proposes a new heat pump type air conditioner for vehicles. In this device, a heat-dissipating vehicle interior heat exchanger is provided in addition to a heat-absorbing vehicle interior heat exchanger, and switching is performed by a three-way valve. According to such a device, it is possible to improve the cooling and heating capacity with stable control irrespective of climatic conditions outside the vehicle compartment, without requiring a significant design change, suitable for electric vehicles, etc., and to perform dehumidifying heating. Can be.

FIG. 7 shows a specific example. During the heating operation, the three-way valve 32 is switched as shown by the solid line, and the refrigerant flows from the compressor 31 → the three-way valve 32 → the heat exchanger 33 for heat dissipation → the liquid tank 36 → the expansion valve 34 → the heat exchanger for heat absorption in the car. 35 → circulates with the compressor 31. Then, the air introduced by the blower fan is cooled by heat exchange in the heat absorbing vehicle interior heat exchanger 35, cooled and dehumidified, and then heated by the heat exchange in the heat releasing vehicle interior heat exchanger 33 to be heated. Hot air is produced for heating.

During the cooling operation, the three-way valve 32 is switched as shown by the dotted line, and the refrigerant is supplied to the compressor 31 →
The three-way valve 32 → the heat exchanger 38 outside the vehicle compartment → the check valve 70 → the heat exchanger 33 for heat dissipation inside the vehicle → the liquid tank 36 → the expansion valve 34 → the heat exchanger 35 for heat absorption inside the vehicle → the compressor 31 circulates.
Then, the exterior heat exchanger 38 radiates the heat of the high-temperature refrigerant discharged from the compressor 1 to the outside air, and the air introduced by the blower fan is exchanged with the heat absorbing interior heat exchanger 35 to be cooled. Cold air is created for cooling the vehicle interior.

As described above, in this new air conditioner,
During the heating operation, dehumidification is performed by cooling of the heat absorbing vehicle interior heat exchanger 35, and reheating is performed by the heat releasing vehicle interior heat exchanger 33. Therefore, theoretically, the amount of heat input to the compressor is used as heating heat, and a heat source such as an electric heater is used. Dehumidifying and heating operation can be performed without the need. Therefore, by increasing the input of the compressor 31, a sufficient dehumidifying and heating operation can be performed.

[0014]

By the way, in the cooling and heating apparatus shown in FIG. 7, when the temperature of the refrigerant discharged from the compressor increases during the cooling high load operation, the compressor speed is reduced by, for example, frequency control to protect the compressor. Although this can be achieved, there is a risk that the cooling capacity will be reduced. For this reason, it is necessary to ensure a sufficient margin for the load of the compressor, and it is inevitable that the apparatus becomes large.

Accordingly, the present invention avoids a compressor protection operation caused by a rise in the compressor discharge refrigerant temperature during a high-load cooling operation, thereby preventing a reduction in cooling capacity and an increase in the size of the vehicle. It is an object to provide a heat pump type cooling and heating device for use.

[0016]

According to a first aspect of the present invention, there is provided a compressor for adding work to a refrigerant, and the compressor is connected to a refrigerant discharge side of the compressor to transfer heat of the refrigerant to outside air. An external heat exchanger that radiates heat to the vehicle; a heat exchanger that is connected to the refrigerant discharge side of the compressor and radiates heat of the refrigerant to air introduced by the blowing means to generate warm air; Expansion means connected to the refrigerant outflow side of the vehicle interior heat exchanger for adiabatically expanding the refrigerant,
The heat of the air, which is connected between the refrigerant discharge side of the expansion means and the refrigerant suction side of the compressor, and is introduced by the blowing means, is transmitted from at least one of the exterior heat exchanger and the heat radiation interior heat exchanger. A heat-absorbing vehicle interior heat exchanger that absorbs heat into the refrigerant supplied through the expansion means to produce cool air;
The compressor is provided between a refrigerant discharge side of the compressor and a refrigerant inflow side of the exterior heat exchanger and the heat radiation interior heat exchanger, and discharges refrigerant discharged from the compressor at least during the cooling operation during the cooling operation. Refrigerant flow switching means for introducing into the heat exchanger for avoiding the outside heat exchanger during the heating operation and introducing the heat exchanger for heat dissipation, and compressor load state detecting means for detecting the load state of the compressor. During cooling high-load operation, the compressor load state is detected when the air flow rate at which the cooling state in the heat absorbing interior heat exchanger falls within a set range is set, and the load state of the compressor exceeds a preset high load state. Means for controlling the air flow of the air blower in a decreasing direction with the set air flow as an upper air flow when detected by the air blower;
Means for setting the set airflow as an upper limit airflow,
Control the amount of load on the compressor
Before the state has exceeded the state higher than the set state
The compressor load condition detection means detects that
A compressor for controlling the rotation speed of the compressor
Control means .

[0017]

According to a second aspect of the present invention, there is provided the heat pump type cooling and heating apparatus for a vehicle according to the first aspect , wherein the compressor control means controls the rotational speed with a predetermined hysteresis.

According to a third aspect of the present invention, there is provided the heat pump type cooling / heating apparatus for a vehicle according to the first or second aspect , wherein the passage of the heat exchanger outside the vehicle compartment is performed based on a determination that the compressor is protected. A compressor protection control means is provided for controlling at least one of an air volume and a switching of air introduced into the heat absorbing vehicle interior heat exchanger between the inside and outside of the vehicle and a ratio of an air volume passing through the heat releasing vehicle interior heat exchanger. It is characterized by the following.

According to the fourth aspect of the present invention, any one of the first to third aspects is provided.
The vehicle heat pump type cooling and heating apparatus of crab according,
In the compressor, a built-in drive motor is cooled by a refrigerant, and an accumulator is provided between the heat-absorbing vehicle interior heat exchanger and a compressor suction side.

[0021]

According to the first aspect of the present invention, the air flow is set such that the cooling state in the heat absorbing heat exchanger in the interior of the heat-exchanging heat exchanger is within the set range during the high-load cooling operation, and the load state of the compressor is set to a predetermined high level. When the load exceeds the load state, the air volume of the blower is controlled in a decreasing direction with the set air volume as an upper limit. For example, when the air volume of the air blower decreases, the air volume passing through the heat-absorbing vehicle interior heat exchanger decreases, the heat exchange amount decreases, and the operating temperature and operating pressure of the heat-absorbing vehicle interior heat exchanger decrease. The temperature of the blown air drops. At this time, the operating temperature and operating pressure of the heat-absorbing vehicle interior heat exchanger decrease, so that the pressure difference at the expansion valve inlet / outlet increases, and passes through the expansion valve from the heat-absorbing vehicle interior heat exchanger to the compressor suction side. Up to the low pressure section. Therefore,
As a result, the temperature of the refrigerant drawn into the compressor can be kept low, and the load on the compressor can be reduced. In addition, from the viewpoint of cooling capacity, the air volume is reduced, but the temperature of the air blown out of the heat absorbing vehicle interior heat exchanger is reduced, and the compressor rotation speed is not reduced by the operation of the compressor protection, so that the cooling capacity is maintained. .

Further, when it exceeds the set state load state higher compressor is detected by the compressor load condition detecting means, it is possible to control the rotational speed of the compressor by the compressor control means reduces the rotational speed be able to.

According to the second aspect of the present invention, in addition to the operation of the first aspect of the present invention, the rotational speed of the compressor can be controlled with hysteresis.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect of the present invention, when the compressor is protected, the control means for protecting the compressor controls the amount of air passing through the heat exchanger outside the vehicle compartment and the heat exchanger for absorbing heat. It is possible to control at least one of the switching of the introduced air between the inside and outside of the vehicle and the ratio of the amount of air flowing through the heat exchanger inside the vehicle for heat dissipation.

According to the fourth aspect of the present invention, any one of the first to third aspects is provided.
In addition to the operation of the invention, by storing the refrigerant in the accumulator, the refrigerant can be sufficiently guided to the drive motor built in the compressor.

[0026]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of a vehicle heat pump type air conditioner according to an embodiment of the present invention. In this cooling / heating device, the compressor 31 is provided outside the vehicle compartment such as an engine room, and has a built-in drive motor 31a.
The discharge capacity can be changed by adjusting the rotation speed of the drive motor 31a by changing the frequency of the drive signal. The refrigerant discharge side of the compressor 31 is connected to a heat exchanger 38 outside the vehicle compartment and a heat exchanger 33 for the heat radiation inside the vehicle via a three-way valve 32 as a flow path switching means. The vehicle exterior heat exchanger 38 is provided outside the vehicle room such as an engine room, and functions as a vehicle exterior capacitor that radiates heat of the refrigerant discharged from the compressor 31 to the outside air.

The heat-exchanger interior heat exchanger 33 is provided in a duct 39 serving as an apparatus body disposed at the front of the interior of the vehicle interior, such as the back side of the instrument panel, and transfers heat of the refrigerant discharged from the compressor 31. It is a heat-dissipating type vehicle interior condenser that radiates heat to the air introduced by the blower fan 37 as a blowing means.

During the heating operation, the three-way valve 32 is in a flow path switching state as indicated by a dotted line, and connects the discharge side of the compressor 31 to the refrigerant inflow side of the heat-dissipating vehicle interior heat exchanger 33. The flow path is switched as shown by the solid line, and the discharge side of the compressor 31 is connected to the heat-radiating interior heat exchanger 3 via the exterior heat exchanger 38 and the check valve 70.
3 is connected to the refrigerant inflow side.

The check valve 70 allows the flow of the refrigerant from the heat exchanger 38 outside the vehicle compartment to the heat exchanger 33 inside the heat radiating vehicle,
The flow of the refrigerant from the heat-radiating vehicle interior heat exchanger 33 to the vehicle exterior heat exchanger 38 is prevented.

On the refrigerant outflow side of the heat radiating vehicle interior heat exchanger 33, the refrigerant inflow side of the heat absorbing vehicle interior heat exchanger 35 provided on the upstream side in the duct 39 is provided outside the liquid tank 36 and the vehicle interior. The expansion means is connected via an expansion valve 34 which adiabatically expands the liquid refrigerant to form a mist.

The heat exchanger 35 for absorbing heat inside the vehicle is provided with a duct 39.
The heat exchanger is disposed upstream of the inside heat exchanger 33 for heat dissipation, and transfers the heat of the air introduced by the blower fan 37 to the outside heat exchanger 38 and the inside heat exchanger 3 for heat dissipation.
3 is an endothermic evaporator that absorbs the refrigerant supplied from at least one of the three through the expansion valve 34 to generate cool air.

An accumulator 91 is connected between the refrigerant outflow side of the heat absorbing passenger compartment heat exchanger 35 and the refrigerant suction side of the compressor 31. The accumulator 91 has at least an inner volume that is larger than the inner volume of the exterior heat exchanger 38. Even when the cooling operation and the heating operation are switched, the residual refrigerant amount in the exterior heat exchanger 38 becomes zero. Also, the refrigerant is prevented from overflowing from the accumulator 91.

On the upstream side of the heat absorbing heat exchanger 35 in the duct 39, there are provided an inside air introducing pipe 40 for introducing the air inside the vehicle and an outside air introducing pipe 41 for introducing the outside air by receiving the traveling wind pressure. It is connected. At a portion where the inside air introduction pipe 40 and the outside air introduction pipe 41 are branched, an intake that opens and closes so that the inside air introduced from the inside air introduction pipe 40 and the outside air introduced from the outside air introduction pipe 41 are supplied at an arbitrary ratio. Door 4
2 are provided. The intake door 42 is opened and closed by an unillustrated intake door actuator driven by a command from the control device 43.

The blower fan 37 is disposed between the inside air introduction pipe 40 and the outside air introduction pipe 41 between the air outlet side (downstream side of the air flow) and the heat absorbing vehicle interior heat exchanger 35. The motor 44 is driven to rotate.

An air mix door 46 is provided on the upstream side of the heat exchanger 33 for heat dissipation. The air mixing door 46 is driven by an air mixing door actuator (not shown) driven by the control device 43, and cools the air passing through the heat absorbing vehicle interior heat exchanger 35 and dissipating the heat. A ratio (a distribution of the air volume between the cold air and the hot air) that separates the cold air that is kept cold while avoiding the air 33 and the warm air that has been heated by passing through the heat exchanger 33 is adjusted.

The air-mix door opening Xdsc, which is the opening of the air-mix door 46, is such that the air-mix door 46 is located at the position indicated by the dashed line, and the distribution of the air volume between the cold air and the hot air is 10 cm.
When 0%, the air mix door opening Xdsc = 0%
(Fully closed = F / C = full cool), and when the air mix door 46 is at the position indicated by the two-dot chain line and the air flow distribution between the cold air and the hot air is 100% hot air, the air mix door is opened. The degree Xdsc is set to 100% (full open = F / H = full hot).

The heat exchanger 3 for radiating heat in the duct 39
Downstream from 3, an air mix chamber 47 is provided as a room for creating a temperature-conditioned conditioned air by improving the mixing of the cold air and the hot air. In the air mix chamber 47, a ventilator outlet 51 (51a, 51b) that blows out conditioned air toward the upper body of the target occupant.
b, 51c, 51d), a foot outlet 52 (52a) for blowing conditioned air toward the feet of the target occupant, and a defroster outlet 53 (53a) for blowing conditioned air toward the front window. I have.

In the air mixing chamber 47, a ventilator door 55, a foot door 56, and a defroster door 57
Are provided. The ventilator door 55 opens and closes the ventilator outlet 51 with a ventilator door actuator (not shown) driven by the control device 43. The foot door 56 opens and closes the foot outlet 52 by an unillustrated foot door actuator driven by the control device 43. The defroster door 57 opens and closes the defroster outlet 53 by a defroster door actuator (not shown) driven by the control device 43.

A circulation passage 71 communicating with the inside air introduction pipe 40 is connected to the air mix chamber 47. An opening 72 from the circulation passage 71 to the air mixing chamber 47 is provided with an entrance-side door 74 of the circulation passage 71, and a branch portion 73 between the circulation passage 71 and the inside air introduction pipe 40.
Is provided with an exit-side door 75. Entrance side door 7
4, the opening 72 is opened and closed by an entrance door actuator (not shown) driven by the control device 43, and the exit door 75
Switches the branch portion 73 by an outlet door actuator (not shown) driven by the control device 43. That is, in a state where the entrance side door 74 and the exit side door 75 are opened (the exit side door 75 closes the inside air introduction pipe 40).
The conditioned air circulates from the air mix chamber 47 to the upstream side of the blower fan 37.

The control device 43 includes a heat absorbing air temperature sensor 58 for the heat absorbing vehicle interior heat exchanger, a blowing air temperature sensor 59 for the heat absorbing indoor heat exchanger, a ventilator outlet temperature sensor 60, a solar radiation sensor 61, Temperature sensor 62, room temperature sensor 63, room temperature setting device 6 provided on air conditioning setting panel 79
4 (shown by signal lines for convenience in FIG. 1), an outlet mode switch 65 (same), a blower fan switch 66
(Same as above), thermal environment information from a compressor discharge refrigerant temperature sensor 67 (same as above) as a compressor load state detecting means, a blow-out air temperature sensor 68 from a heat dissipation vehicle interior heat exchanger, and the like are input. Thereby, the control device 43
Calculates target air-conditioning conditions such as the air mix door opening Xdsc, the input value Wcomp of the compressor 31, the flow rate Veva of air passing through the heat absorbing vehicle interior heat exchanger 35, and the target outlet temperature Tof. Then, the control device 43 controls the compressor 31, the blower fan motor 44, the air mix door actuator, the ventilator door actuator, the foot door actuator, the defroster door actuator so that the cooling / heating condition in the vehicle compartment maintains the calculated target cooling / heating condition. And outputs a signal for driving the like. In this embodiment, the control device 43 constitutes a blower control unit that controls the blower fan 37 as a blower unit. The control means 43 also constitutes a compressor control means and a compressor protection control means.

Next, the operations during the cooling operation and the heating operation will be described.

During the cooling operation, the three-way valve 32 is switched as shown by the solid line in FIG. 1, and the refrigerant flows from the compressor 31 to the three-way valve 32 to the exterior heat exchanger 38 to the non-return valve 70 to the heat radiation inside the vehicle. It circulates through the exchanger 33 → the liquid tank 36 → the expansion valve 34 → the heat absorbing passenger compartment heat exchanger 35 → the accumulator 91 → the compressor 31.

The heat exchanger 38 outside the vehicle compartment and the heat exchanger 33 for the heat radiation function as a radiator, and the heat exchanger 38 outside the vehicle radiates the heat of the high-temperature refrigerant discharged from the compressor 31 to the outside air. And dissipates the remaining heat to the heat exchanger 3
3 radiates heat to the air introduced by the blower fan 37 or the air introduced by the ram pressure during traveling of the vehicle to produce warm air. Further, the heat absorbing vehicle interior heat exchanger 35 functions as a heat absorber, and radiates the heat of the air introduced by the blower fan 37 or the air introduced by the ram pressure when the vehicle travels to the refrigerant to produce cool air. Therefore, by cooling and dehumidifying and heating the vehicle interior air, it is possible to supply a suitable temperature conditioned air to the vehicle interior. Further, by separately taking out the cold air and the hot air, it is possible to supply conditioned air having a temperature difference between the upper and lower sides of the vehicle interior, for example.

During the heating operation, the three-way valve 32 is switched as shown by the dotted line, and the refrigerant is supplied from the compressor 31 → the three-way valve 32 → the heat exchanger 33 for heat dissipation → the liquid tank 36 →
It circulates in the order of the expansion valve 34 → the heat absorbing vehicle interior heat exchanger 35 → the accumulator 91 → the compressor 31.

Then, the heat radiating vehicle interior heat exchanger 33 radiates the heat of the high-temperature refrigerant discharged from the compressor 31 to the air introduced by the blower fan 37 or the air introduced by the ram pressure during traveling of the vehicle. Then, the heat absorbing vehicle interior heat exchanger 35 absorbs the heat of the air introduced by the blower fan 37 or the air introduced by the ram pressure during traveling of the vehicle into the refrigerant to produce cold air. Here, the blower fan 37
The temperature of the air introduced in the step (1) is maintained at an appropriate temperature by circulating the air, so that a sufficient heating effect can be obtained even when the outside air is at a low temperature. After cooling and dehumidification by the heat absorbing vehicle interior heat exchanger 35, the heat releasing vehicle interior heat exchanger 3
Since heating is performed in step 3, dehumidifying heating becomes possible, and fogging of the window can be prevented. During this heating operation, the vehicle exterior heat exchanger 38 is not used. Therefore, even when the outside air temperature is low and there is a possibility that the outside heat exchanger 38 may freeze, the heating operation can be stably performed by preventing the refrigerant from passing through the outside heat exchanger 38.

Next, the operation of the control device 43 during the cooling operation will be described with reference to the flowcharts shown in FIGS. 2, 3 and 4.

When the cooling operation is started in step 201,
In step 202, signals of various sensor outputs are read. Here, a set temperature Tpt which is an output signal of the room temperature setter 64 is used.
c, a room temperature Troom which is an output signal of the room temperature sensor 63,
The outside air temperature Tamb, which is an output signal of the outside air temperature sensor 62, and the heat absorbing vehicle interior heat exchanger 35, which is an output signal of the wind temperature sensor 59.
, And the suction air temperature Tsuc of the heat absorbing vehicle interior heat exchanger 35, which is an output signal of the wind temperature sensor 58, is read. Further, the output signal of the wind temperature sensor 68 is the output air temperature Tv of the heat-dissipating interior heat exchanger 33, the applied voltage Vfan of the fan motor 44, the insolation Qsun which is the output signal of the insolation sensor 61, and the refrigerant temperature sensor 67. , The compressor discharge refrigerant temperature Td, the number of revolutions (input frequency) Hz of the compressor 31, and the like.

In the next step 203, step 202
Calculates the target outlet temperature Tof corresponding to the in-vehicle air-conditioning load from the sensor output value read in. In step 204,
According to the target outlet temperature Tof calculated in step 203,
The opening of the intake door 42 is set. Here, when the target outlet temperature Tof is low, the heat load on the vehicle is large, so that the intake amount of outside air is reduced, and the intake amount of outside air is gradually increased as the target outlet temperature Tof increases. . That is, as the target outlet temperature Tof is lower, the intake door 42 is set to the REC side, and as the target outlet temperature Tof is higher, the intake door 42 is set to the FRE side.

In the next step 205, step 203
The outlet mode is selected in accordance with the target outlet temperature Tof calculated in. Here, VENT blowing (vent mode) is set when the target blowing temperature Tof is low, and B / L blowing (bi-level mode) is set when the target blowing temperature Tof increases to some extent.

In step 206, it is determined whether the compressor discharge refrigerant temperature Td is higher than the first set temperature Tset1. In this case, the first set temperature Tset1 is a reference temperature for judging that it is not preferable if the load state of the compressor is higher than that. The first set temperature Tset1 is set to 80 to 90 ° C. The setting method will be described later together with a second set temperature Tset2 described later.

If Td.ltoreq.Tset1, it can be considered that there is room in the refrigerant temperature discharged from the compressor, so that the determination in step 206 becomes NO, and the process proceeds to step 207 to perform a normal cooling operation.

Conversely, when Td> Tset1, it can be determined that the load on the compressor 1 is high, so the determination in step 206 becomes YES, and the flow proceeds to step 214 to reduce the load on the compressor. Control. That is, steps after step 214 are steps for controlling when the load state of the compressor exceeds a preset high load state, which is a characteristic step of the present invention.

In step 207, step 203
Blower voltage Vfa according to the target outlet temperature Tof calculated by
Set n. Here, when the target outlet temperature Tof is equal to or lower than the first predetermined value Tof-1, the blower voltage Vfan is set high in order to increase the air volume and increase the cooling capacity as the Tof decreases. Further, the target outlet temperature Tof is set to the first predetermined value Tof.
If it exceeds -1, the blower voltage Vfan is set to the minimum value irrespective of the target blowing temperature Tof.

In step 208, a target Tout is calculated as a target value of the temperature of the air blown out of the heat exchanger 35. Here, since the air mixing door 46 is set to the fully closed position and the operation of blowing air into the vehicle interior without passing through the heat radiation interior vehicle heat exchanger 33 is performed, the target blowing temperature Tof calculated in step 203 is directly used as the heat absorbing vehicle. The target value (target Tout) of the temperature of the air blown out from the indoor heat exchanger 35 is set.

In step 209, a deviation Δθ between the target Tout calculated in step 208 and the actual blown air temperature Tout of the heat absorbing heat exchanger 35 read in step 202 is calculated.

In step 210, the magnitude of the deviation Δθ calculated in step 209 is determined, and Δθ <−s (where
s is a value for forming a dead zone for stabilizing the operation), it means that the blown air temperature Tout of the heat absorbing vehicle interior heat exchanger 35 is higher than the target Tout. Then, the rotation speed (frequency) Hz of the compressor 31 is increased by ΔHz, and the compressor control is performed in a direction in which the blown air temperature Tout of the heat absorbing vehicle interior heat exchanger 35 decreases.

Conversely, if Δθ> s, it means that the blown air temperature Tout of the heat absorbing vehicle interior heat exchanger 35 is lower than the target Tout, so the routine proceeds to step 213, where the rotational speed of the compressor 31 ( The frequency (Hz) is decreased by ΔHz, and the compressor is controlled in a direction in which the temperature Tout of the blown air of the heat exchanger 35 for absorbing heat becomes higher.

When −s ≦ Δθ ≦ s, the temperature Tout of the air blown from the heat absorbing vehicle interior heat exchanger 35 is equal to the target Tout.
Is almost the same as
Proceeding to step 212, the current compressor rotation speed (frequency) Hz is maintained as it is.

When the compressor control in step 211 or step 213 is completed, the flow returns to step 202, and the control during the cooling operation is repeated.

On the other hand, if the compressor refrigerant temperature Td is higher than the first set temperature Tset1 and the process proceeds from step 206 to step 214, the blower voltage is set in step 214 according to the target blow temperature Tof. However, in this case, the target outlet temperature Tof is the first predetermined value Tof-1 described above.
When it is equal to or lower than a second predetermined value Tof-2, the blower voltage Vfan (corresponding to the air volume) is set with the voltage Vfan.set as an upper limit. In this case, the air volume is set such that the cooling state in the heat absorbing vehicle interior heat exchanger 35 (including the cooling state of the blown air from the heat absorbing vehicle interior heat exchanger 35) is within the set range. If the target outlet temperature Tof is higher than the second predetermined value Tof-2, the blower voltage control having the same contents as the normal blower voltage control in step 207 is performed.

When the blower control in step 214 is performed, the amount of air passing through the heat absorbing vehicle interior heat exchanger 35 decreases, the operating temperature and operating pressure of the heat absorbing vehicle interior heat exchanger 35 decrease, and the blown air temperature decreases. Decrease. At this time, the operating temperature and the operating pressure of the heat-absorbing cabin heat exchanger 35 decrease, so that the pressure difference at the inlet and outlet of the expansion valve increases, so that the heat-absorbing cabin heat exchanger 35 passes through the expansion valve 34 and the compressor. The amount of refrigerant that accumulates in the accumulator 91 in the low pressure section between the suction side and the suction side 31 increases. Therefore, the temperature of the compressor suction refrigerant decreases, the load state of the compressor 31 is reduced, and the compressor discharge refrigerant temperature Td higher than the set temperature Tset1 decreases. The accumulator 9
Since the drive motor 31a built in the compressor 31 is cooled by the refrigerant accumulated in 1, the compressor discharge refrigerant temperature Td is reduced more effectively. From the viewpoint of the cooling capacity, although the amount of blown air is reduced, the temperature of the blown air from the heat-absorbing vehicle interior heat exchanger 35 is reduced and the compressor speed is not reduced, so that the cooling capacity is maintained. Become.

In step 215 following the blower control in step 214, it is determined whether the compressor discharge refrigerant temperature Td is higher than a second set temperature Tset2. here,
The relationship between the first set temperature Tset1 and the second set temperature Tset2 is Tset1 <Tset2. This second set temperature Tset2
Is a reference temperature for judging whether or not to perform compressor rotation speed reduction control for compressor protection, and is set to Tset1 to 100 ° C. The setting method will be described later.

If Td ≦ Tset2 as a result of performing the blower control in step 214, step 21
The determination at 5 is NO, and the routine proceeds to step 216. In step 216, the target Tout is calculated in consideration of the air flow correction amount α so as to maintain the cooling capacity even if the air flow is reduced, in consideration of the blower voltage reduction lowered in step 214. That is, the target Tout is corrected to be smaller by α than the target blowout temperature Tof, and the routine proceeds to a normal cooling operation control step after step 209.

Here, if Td> Tset2 as a result despite the blower control in step 214, the process proceeds to step 217. In and after step 217, control is performed to forcibly decrease the compressor rotation speed (frequency) in order to protect the compressor 31 by lowering the compressor discharge refrigerant temperature Td. Even if the compressor discharge refrigerant temperature Td increases, in most cases, by performing the blower control in step 214, the compressor discharge refrigerant temperature Td decreases and normal cooling operation can be continued. If there is a shortage of the working refrigerant or if the outlet air of the heat-exchanging exterior heat exchanger 38 is blown back, the compressor discharge refrigerant temperature Td does not decrease and the routine proceeds to step 217. If Td ≦ Tset2 after executing the compressor protection control after step 217, the operation of compressor protection is canceled by proceeding from step 215 to step 216.

At step 217, it is determined whether or not the compressor protection has just started. Since the compressor protection control has been started at the stage when step 217 is entered, when step 217 is first entered, step 21 is executed.
7 is YES, the process proceeds to step 218, where the compressor rotation speed (frequency) Hz at the start of compressor protection is stored, and then the process proceeds to step 219. From the next time, step 218 is passed and the process proceeds directly to step 219.

In step 219, the rotational frequency (frequency) Hz of the compressor 31 is forcibly corrected to a value lower than the stored value Hz at the start of compressor protection in accordance with the compressor discharge refrigerant temperature Td, and the compressor discharge temperature Td is corrected. Suppress the rise. The correction amount of the rotation speed Hz of the compressor 31 increases stepwise as the compressor discharge refrigerant temperature Td increases, and the compressor discharge refrigerant temperature Td increases.
When d changes in a direction to increase, the correction amount gradually increases stepwise. Also, the compressor discharge refrigerant temperature Td
When the value changes in a direction to decrease, the correction amount gradually decreases stepwise. Then, a hysteresis is provided between the judgment values when the correction amount increases and when the correction amount decreases.
Therefore, the discharge refrigerant temperature indicating the load state of the compressor 31 is equal to the first set temperature Tse as a preset set state.
The second set temperature Tset2 is set as a set state higher than t1.
Is detected, the rotational speed of the compressor 31 is controlled. This control is performed with hysteresis as described above.

When the process of step 219 is completed,
Returning to step 202 again, the control during the cooling operation is repeated.

The first set temperature Tse of the compressor discharge refrigerant temperature Td in steps 206 and 215 described above.
t1 (80 to 90 ° C.), the second set temperature Tset2 (Tset1 to
100 ° C.) is set in consideration of the following conditions (1) to (4). That is, in the case of a hermetic compressor with a built-in motor, the temperature of the discharged refrigerant is about 110 ° C to protect the coil of the motor.
It must be: During the cooling operation, heat is mainly radiated from the outside heat exchanger 38, so that the compressor discharge pressure is lower than that during the heating operation,
The discharge temperature of the compressor tends to increase. Since the temperature of the refrigerant discharged from the compressor is detected by a temperature sensor wound around the surface of the discharge pipe of the compressor, the error and the change speed vary depending on the running state of the vehicle, the presence or absence of sound insulation measures of the compressor, the characteristics of the temperature sensor, and the like. Frequent changes in the air flow due to the activation of the compressor protection may impair comfort. When the vehicle is stopped under high cooling load conditions, the occupant starts to feel a decrease in the cooling capacity when the temperature of the refrigerant discharged from the compressor exceeds about 80 ° C.

As described above, according to the present embodiment, the compressor discharge refrigerant temperature Td is set to the first set temperature Ts at the time of high cooling load.
If et1 is exceeded, first, the blower voltage is dropped (in practice, only when the target blowout temperature Tof is smaller than the second predetermined value Tof-2, the blower voltage Vfan drops below the value during normal operation). However, when the cooling load is high, the target outlet temperature T
is smaller than the second predetermined value Tof-2, so there is no problem assuming that the blower voltage drops.) Therefore, the amount of air passing through the heat absorbing vehicle interior heat exchanger 35 is reduced to reduce the compressor discharge refrigerant temperature Td. To decrease. Still, if the compressor discharge refrigerant temperature Td rises, it is the first time at that stage that an emergency has occurred and the compressor protection is activated,
The compressor rotation speed is lowered to lower the compressor discharge refrigerant temperature Td. Therefore, when the compressor discharge refrigerant temperature Td is being reduced by reducing the blower voltage, the compressor rotation speed is maintained at the current level, and the compressor discharge refrigerant temperature Td can be reduced without lowering the cooling capacity. Can be.

In the present embodiment, the compressor discharge refrigerant temperature Td is used as the temperature representative of the load state of the compressor. However, the compressor shell temperature, the coil temperature of the compressor built-in motor 31a, or the like may be used.

Further, in this embodiment, when the compressor discharge refrigerant temperature Td rises, the blower voltage is forcibly reduced to reduce the amount of air passing through the heat absorbing vehicle interior heat exchanger 35, so that the refrigerant moves to the low pressure side. Although it was made to accumulate, the intake door 42 was controlled so as to further reduce the amount of outside air introduced, and the cooling fan 38a for the heat exchanger (condenser) outside the vehicle compartment was used.
May be controlled so as to increase the air flow rate, to control the air mix door opening slightly to the opening side, and to control the expansion valve 34 to increase the opening.

FIG. 5 shows the control of the condenser fan 38a, the intake door 42, and the air mix door 46 performed during the compressor protection (here, the blower control in step 214 is also included as compressor protection in a broad sense). . Here, the control of the condenser fan 38a controls the amount of air passing through the outside heat exchanger 38. The control of the intake door 42 controls the switching of the air introduced into the heat absorbing heat exchanger 35 inside and outside the vehicle interior. The control of the air mix door controls the ratio of the amount of air passing through the heat exchanger 33 for heat radiation. This control is performed, for example, by interrupting the control of FIG. 2 for a predetermined time.

First, if it is determined in step 501 that the compressor is being protected, the process proceeds to step 502, where a condenser fan (not shown in FIG. 1,
It is determined whether or not the fan attached to the outside heat exchanger 38 is Hi (high rotation). If the condenser fan is not Hi, the process proceeds to step 503. Set the condenser fan to Hi.
By setting the condenser fan to Hi, heat radiation is promoted, and an increase in the compressor discharge refrigerant temperature Td can be suppressed. Therefore, the cooling capacity of the heat absorbing vehicle interior heat exchanger 35 can be increased.

At step 504, the intake door 42
Is determined to be in the internal air circulation (REC), and if not, the process proceeds to step 505 to set the intake door 42 to the internal air circulation. By making the intake door 42 circulate inside air, the temperature and humidity of the air flowing into the heat absorbing interior heat exchanger 35 decrease. Therefore, the heat load of the heat absorbing vehicle interior heat exchanger 35 can be reduced.

In step 506, the air mix door 4
It is determined whether or not 6 is fully closed (F / C = full cool). If the air mix door 46 is fully closed, the process proceeds to step 507, and the air mix door is opened by several tens%. When the air mixing door 46 is opened by several tens of percent, a part of the air cooled by the heat-absorbing vehicle interior heat exchanger 35 flows into the heat-radiating vehicle interior heat exchanger 33, where heat exchange is performed. Become. In other words, the refrigerant passing through the heat exchanger 33 inside the heat radiating compartment is somewhat cooled. When even a small amount of the refrigerant is cooled by the heat exchanger 33 for heat dissipation,
Although the outlet temperature rises slightly, the cooling capacity of the heat absorbing heat exchanger 35 increases.

Therefore, the condenser fan 38a, the intake door 42, and the air mix door 46 as described above
When the compressor is protected, for example, when the rotation speed of the compressor 31 is reduced, the cooling capacity can be prevented from lowering.

The above-described embodiment utilizes the fact that the temperature of the refrigerant discharged from the compressor 31 decreases when the air flow rate passing through the heat absorbing interior heat exchanger 35 is reduced at the time of high cooling load. The inventors have found the following experiments.

FIGS. 5 (a) to 5 (d) show the variation of the blower voltage Vfan using a 2000 cc class vehicle, with the compressor rotating speed (frequency) kept constant under an external air temperature of 35.degree. Compressor discharge pressure P
d, an example of an experimental result obtained by examining changes in a blown air temperature Tout, a refrigerant discharge refrigerant temperature Td, and a compressor input Wcomp of a heat absorbing vehicle interior heat exchanger.

FIG. 5A shows that the compressor discharge refrigerant pressure Pd is substantially constant even when the blower voltage Vfan is changed. Since the compressor rotation speed (frequency) is constant, the compressor input Wcomp is also substantially constant as shown in FIG. According to FIG. 5B, when the blower voltage Vfan is reduced, the temperature Tout of the air blown out of the heat absorbing interior heat exchanger 35 decreases with a decrease in the air volume. From these results, it was found that the cooling capacity was maintained substantially constant even when the blower voltage Vfan was changed because the work of the compressor was the same.

According to FIG. 5D, the blower voltages 7 to 12
Between V, the compressor discharge refrigerant temperature Td was higher than the temperature at which the compressor rotation speed must be reduced to protect the compressor. However, when the blower voltage Vfan was gradually lowered from 7V, the compressor discharge refrigerant temperature Td dropped sharply, and the compressor discharge temperature Td at the time of the blower voltage of 5V dropped by more than 20 ° C than at the time of the blower voltage of 7 to 12V. .

As a result, when the compressor discharge refrigerant temperature Td rises and it is necessary to lower the compressor discharge refrigerant temperature Td in order to protect the compressor, the compressor rotation speed is reduced and the compressor discharge refrigerant temperature Td is reduced as in the conventional case. It has been found that the effect can be expected when the blower voltage Vfan is set to 6 V or less, and the cooling capacity can be maintained, rather than reducing the blower voltage.

Therefore, it is clear that the above-mentioned embodiment has the above-mentioned expected effects.

In the above embodiment, the compressor discharge refrigerant temperature sensor 6 is used as the compressor load state detecting means.
7, a sensor for detecting the compressor shell temperature, the coil temperature of the compressor built-in motor 31a, and the like can also be used.

[0085]

As is apparent from the above, according to the first aspect of the present invention, when the cooling load is high, the amount of air in which the cooling state in the heat absorbing heat exchanger in the vehicle interior is within the set range is set, and the load on the compressor is reduced. When the state exceeds the set state, the air flow rate of the heat absorbing vehicle interior heat exchanger is controlled with the set air volume as an upper limit, so that the blown air temperature of the heat absorbing vehicle interior heat exchanger decreases,
In addition, the compressor discharge refrigerant temperature can be reduced without lowering the compressor rotation speed for compressor protection, and the cooling capacity is not reduced due to the reduction in the compressor rotation speed. Therefore, the compressor can be protected while maintaining the cooling capacity.

[0086] Further, the rotational speed of the compressor can be reduced when a load state load state higher compressor regardless of the control of the blowing means, it is possible to protect the compressor.

According to the second aspect of the present invention, by controlling the number of rotations of the compressor with hysteresis, stable rotation can be obtained while controlling the number of rotations of the compressor.

According to the third aspect of the present invention, a decrease in the cooling capacity can be suppressed even when the compressor is protected.

According to the fourth aspect of the present invention, the drive motor built in the compressor can be reliably cooled, and a stable cooling capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing a control operation during a cooling operation in the embodiment.

FIG. 3 is a flowchart showing a continuation of FIG. 2;

FIG. 4 is a flowchart showing control contents performed in parallel with the control operation shown in the flowchart of FIG. 2;

5A and 5B are characteristic diagrams showing experimental results when the control of the embodiment is performed, wherein FIG. 5A is a diagram showing a relationship between a blower voltage and a compressor discharge pressure, and FIG. A diagram showing the relationship between the heat exchanger blown air temperature, (c) is a diagram showing the relationship between the blower voltage and the compressor input, (d)
FIG. 4 is a diagram showing a relationship between a blower voltage and a refrigerant discharge refrigerant temperature.

FIG. 6 is a configuration diagram of a refrigeration cycle according to a conventional example.

FIG. 7 is a configuration diagram of a refrigeration cycle of a conventional vehicle heat pump air conditioner that is a premise of the present invention.

[Explanation of symbols]

31 Compressor 31a Compressor built-in motor (drive motor) 32 Three-way valve (refrigerant flow path switching means) 33 Heat dissipation vehicle interior heat exchanger 34 Expansion valve (expansion means) 35 Heat absorbing vehicle interior heat exchanger 37 Blower fan (blower means) 38 Outside heat exchanger 43 Control device (blower control means, compressor control means, compressor protection control means) 67 Compressor discharge refrigerant temperature sensor (compressor load state detection means) 91 accumulator

Claims (4)

(57) [Claims] A compressor that adds work to the refrigerant; a vehicle exterior heat exchanger that is connected to a refrigerant discharge side of the compressor and radiates heat of the refrigerant to the outside air; and a refrigerant that is connected to a refrigerant discharge side of the compressor. A heat-dissipating vehicle interior heat exchanger that radiates the heat of the air to the air introduced by the blowing means to generate warm air, and an expansion means that is connected to the refrigerant outflow side of the heat-dissipating vehicle interior heat exchanger and adiabatically expands the refrigerant. And connected between the refrigerant discharge side of the expansion means and the refrigerant suction side of the compressor, at least one of the exterior heat exchanger and the heat radiation interior heat exchanger for transferring the heat of the air introduced by the air blowing means. A heat-absorbing vehicle interior heat exchanger that absorbs heat from the refrigerant supplied through the expansion means to generate cool air, a refrigerant discharge side of the compressor, the vehicle exterior heat exchanger, and the heat radiation vehicle interior heat exchanger. The refrigerant discharged from the compressor, which is provided between the refrigerant inflow side, is introduced into at least the exterior heat exchanger during the cooling operation, and is circumvented from the exterior heat exchanger during the heating operation so as to avoid the heat radiation inside the vehicle. Refrigerant flow switching means to be introduced into the heat exchanger, compressor load state detecting means for detecting the load state of the compressor, and a cooling state in the heat absorbing vehicle interior heat exchanger within a set range during a cooling high load operation. When the compressor load state detecting means detects that the load state of the compressor has exceeded a preset high load state,
Blowing control means for controlling the airflow of the blowing means in a decreasing direction with the set airflow as an upper limit airflow , and wherein the blowing control means sets the set airflow as an upper limit airflow.
Based on controlling the air volume of the blowing means,
The load status of the
Is obtained by the compressor load state detecting means.
When detected, control the number of revolutions of the compressor
A heat pump air conditioner for a vehicle, comprising: a compressor control unit . 2. The heat pump air conditioner for a vehicle according to claim 1 , wherein said compressor control means controls said rotation speed with a predetermined hysteresis. 3. A vehicular heat pump type cooling and heating apparatus according to claim 1 or 2, wherein, based on the determination that the protection of the compressor is performed, for the endothermic and amount of air passing through the wheel outdoor heat exchanger Compressor protection control means for controlling at least one of switching of the air introduced into the vehicle interior heat exchanger between inside and outside of the vehicle interior and the ratio of the flow rate of air passing through the heat dissipation interior vehicle heat exchanger is provided. Heat pump type air conditioner for vehicles. 4. A vehicular heat pump type cooling and heating apparatus according to any one of claims 1-3, wherein the compressor is for the built-in drive motor is cooled by the refrigerant, vehicle interior for the endothermic A heat pump type air conditioner for a vehicle, comprising an accumulator provided between a heat exchanger and a compressor suction side.