JP2000052750A - Air-conditioning device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the occurrence of a trouble of an apparatus, of which a device consists, and a slip of a wheel by a low-cost means, in a heat pump heating type heating device having a compressor driven by a vehicle engine. SOLUTION: This air-conditioning device comprises a compressor 6 driven by the shaft output of an engine 1 and feeding compressed refrigerant steam, a heat-exchanger 11 on the indoor side, an expansion means 12, a heat-exchanger 7 on the outdoor side to heat a refrigerant by a heating medium through the expansion means 12, a pressure detecting means 21 to detect the pressure of a refrigerant fed from the compressor 6, and a control means 23 to limit heating of a refrigerant by the heating medium so that a heating amount is reduced or reduced to zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump heating type air conditioner for a vehicle.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 6-227245 discloses an example of a heat pump type air conditioner for a vehicle. This has a cooling operation mode and a heating operation mode, and reduces the load of the vapor compression cycle when the operation mode is switched. That is, since the pressure in the vapor compression cycle changes suddenly when switching between the cooling operation mode and the heating operation mode, the change in the pressure is reduced by reducing the load of the vapor compression cycle at that time, and the vapor compression cycle is configured. It is intended to extend the life of the device that performs the operation.

[0003]

When a heat pump heating type heating device is provided in a gasoline engine vehicle or a diesel engine vehicle and the compressor is driven by the engine, the following problems are not found in the electric compressor. .

[0004] If the vehicle suddenly accelerates during the heating operation, the rotational speed of the compressor rapidly increases with an increase in the engine rotational speed. As a result, the refrigerant pressure may rise sharply, leading to a system abnormality such as breakage of the indoor heat exchanger of the air conditioner. In addition, when an outdoor heat exchanger that heats the refrigerant using the engine cooling water is provided, the capacity of the cooling water pump driven by the engine during this rapid acceleration sharply increases and the engine cooling water is circulated. Flow rate increases rapidly. As a result, the amount of heat received by the refrigerant in the outdoor heat exchanger sharply increases, so that the refrigerant pressure suddenly increases, which may cause a failure of the compressor.

On the other hand, it is conceivable to stop driving the compressor by the engine when the refrigerant pressure suddenly rises as described above. However, this causes the output energy of the engine consumed for driving the compressor to travel to the traveling system of the vehicle, and the driving torque of the wheels suddenly increases. Therefore, when the vehicle is traveling on, for example, a snowy road or a frozen road surface, there is a possibility that wheels may slip.

Further, when the compressor is stopped, the coolant does not lose heat to the coolant in the outdoor heat exchanger, so that the temperature of the coolant rapidly rises. Therefore, when the operation of the compressor is restarted, the refrigerant evaporates violently in the outdoor heat exchanger, and the pressure of the refrigerant rapidly rises again. This further increases the possibility of a compressor failure or wheel slip.

When the occupant operates the air-conditioning operation switch during the heating operation to stop the operation of the compressor, if the pressure of the refrigerant at that time is high, the driving torque of the wheels can suddenly increase and slip. There is. In particular, when the occupant operates the air-conditioning operation switch to stop the compressor, it means that the interior of the room is already sufficiently heated, so that the pressure of the refrigerant at that time is usually high.

Further, when the occupant operates the air volume operation switch to rapidly reduce the flow rate of the air-conditioning air, the heat radiation capacity of the indoor heat exchanger rapidly decreases. as a result,
As in the case where the vehicle suddenly accelerates, the pressure of the refrigerant rapidly rises, causing the same problem as in the case where the vehicle suddenly accelerates.

In view of the above, the present invention provides a heat pump heating type heating device having a compressor driven by an engine, by using inexpensive means to prevent the failure of the compressor and the like of the device and the occurrence of vehicle slippage. It is to prevent it effectively.

[0010]

The invention according to claim 1 of the present application is directed to a compressor driven by the shaft output of an engine to compress and send out a refrigerant vapor, and to generate heat of the refrigerant vapor sent from the compressor. An indoor heat exchanger that radiates heat into the vehicle interior; an expansion unit that evaporates a part of the refrigerant condensed by the indoor heat exchanger; and a heating medium supplied with the heating medium and passed through the expansion unit to the heating medium. In an air conditioner of a heat pump heating type vehicle having an outdoor heat exchanger heated by a pressure detector, a pressure detector for detecting a pressure of a refrigerant sent from the compressor and a refrigerant pressure detected by the pressure detector are set. And a heating limiting means for limiting the heating of the refrigerant by the heating medium when the pressure is increased so that the heating amount is reduced or becomes zero. And wherein the door.

In this air conditioner, the heating of the refrigerant is restricted when the refrigerant pressure rises to the set pressure due to the sudden acceleration operation of the engine or the like, but the state in which heat is taken away by the indoor heat exchanger continues. The specific enthalpy of the refrigerant decreases, and the refrigerant pressure decreases. For this reason, while being advantageous in preventing damage to the equipment constituting the refrigeration cycle,
It is not necessary to stop the compressor immediately, and it is possible to avoid problems such as an excessive increase in the driving torque of the wheels.

According to a second aspect of the present invention, in the vehicle air conditioner according to the first aspect, the refrigerant pressure detected by the pressure detecting means is higher than a first set pressure at which the heating limiting means operates. When the pressure rises to a high second set pressure, the operation of the compressor is limited so as to reduce the work amount or to zero.

That is, in the case where the engine is rapidly accelerated with the downshift of the transmission, the increase in the refrigerant pressure may not be stopped by the limitation of the heating of the refrigerant alone. When the pressure rises to the second set pressure, the operation of the compressor will be limited. On the other hand, since the heat radiation of the refrigerant by the indoor heat exchanger continues, the specific enthalpy of the refrigerant rapidly decreases due to the restriction, and the refrigerant pressure decreases.

The rapid acceleration operation in which the increase in the refrigerant pressure does not stop only by restricting the heating of the refrigerant is performed.
Since the coefficient of friction of the traveling road surface of the vehicle is relatively high (not on a snowy road or a frozen road surface), even if the driving force of the wheels slightly increases due to the stop of the compressor, the influence on the traveling stability of the vehicle is small.

According to a third aspect of the present invention, in the vehicle air conditioner according to the first aspect, the heating restricting means restricts heating of the refrigerant by the heating medium.
When the refrigerant pressure detected by the pressure detecting means drops to a third set pressure lower than the first set pressure at which the heating restriction should be performed, the heating restriction is released.

That is, when the refrigerant pressure is reduced due to the restriction on the heating of the refrigerant, there is no problem such as breakage of the equipment. Therefore, the restriction is released to secure the heating capacity. The reason why the third set pressure at which the restriction should be released is set lower than the first set pressure is to avoid hunting in which the restriction and the release are alternately repeated.

According to a fourth aspect of the present invention, in the air conditioner for a vehicle according to the second aspect, the refrigerant heating restriction means and the compressor operation restriction means are arranged so that the operation of the compressor is restricted. When the refrigerant pressure detected by the pressure detecting means drops to a third set pressure lower than the first set pressure, the heating restriction and the compressor operation restriction are released respectively.

That is, when the refrigerant pressure is reduced due to the operation restriction of the compressor, there is no problem such as breakage of the equipment, so that the restriction of the heating of the refrigerant and the operation restriction of the compressor are released to secure the heating capacity. The reason why the third set pressure at which the restriction should be released is set lower than the first set pressure is to avoid hunting in which the restriction and the release are alternately repeated.

According to a fifth aspect of the present invention, in the vehicle air conditioner according to the first aspect, after the heating of the refrigerant is restricted by the heating restricting means, the refrigerant is detected by the pressure detecting means. When the refrigerant pressure is reduced to a third set pressure lower than the first set pressure at which the heating is to be limited, an operation restricting means for restricting the operation of the compressor so that the work thereof is reduced or becomes zero. It is characterized by having.

When the refrigerant pressure is reduced due to the restriction of the heating of the refrigerant, it is conceivable to release the restriction and secure the heating capacity as in the invention according to claim 3, but in such a case, the refrigerant pressure is reduced. May suddenly rise, causing a failure of the compressor or the like and a slip of the vehicle. Therefore, in the present invention, the operation of the compressor is limited when the refrigerant pressure drops to the third set pressure lower than the first set pressure.

Further, a heating system having a main heating device for directly heating the heating air by a heater core (heating heat exchanger) using the cooling water of the engine and employing the refrigeration cycle as auxiliary heating is employed. In this case, the invention according to claim 5 is particularly useful. In other words, if the refrigerant pressure is increased until the above-mentioned refrigerant heating is restricted, the interior heating is ensured to some extent, and the engine cooling water temperature is also increased, so that all heating is covered by the main heating device. It is often possible to do it.
Therefore, in such a situation, it is considered that auxiliary heating using the refrigeration cycle is no longer necessary when the refrigerant pressure decreases due to the heating restriction.

According to a sixth aspect of the present invention, there is provided a compressor driven by the shaft output of an engine to compress and send a refrigerant vapor, and an indoor heat exchange for radiating heat of the refrigerant vapor sent from the compressor into a vehicle interior. And an expansion means for evaporating a part of the refrigerant condensed by the indoor heat exchanger, and an outdoor heat exchanger for supplying a heating medium and heating the refrigerant passing through the expansion means with the heating medium. In the air conditioner of a heat pump heating type vehicle further provided with an operation switch for operating and stopping the air conditioner in the vehicle compartment, when the operation switch is switched from operation to stop, the compressor of the The operation is continued to limit the heating of the refrigerant by the heating medium so that the amount of heating is reduced or becomes zero. Characterized in that it comprises a a of the working and air-conditioning stop control means for stopping.

In many cases, the occupant stops the operation of the air conditioner by the operation switch when the refrigerant pressure is already high. However, even if such a switch operation is performed, the compressor is immediately stopped. Instead, a state in which a part of the output of the engine is used for the compressor continues, so that it is possible to avoid a situation in which the driving torque of the wheels suddenly increases and the vehicle slips. Further, since the heating of the refrigerant is restricted by the switch operation, the refrigerant pressure starts to decrease, and even if the operation of the compressor is stopped thereafter, the power required for driving the compressor is reduced at that time. Therefore, there is little problem of a sudden increase in the driving torque of the wheels, and the stopping of the air conditioner is based on the intention of the occupant, and it is considered that the heating is already in effect, so there is no particular problem.

According to a seventh aspect of the present invention, in the vehicle air conditioner according to the sixth aspect, there is provided a pressure detecting means for detecting a pressure of a refrigerant sent from the compressor, and the air conditioning stop control means is provided with a pressure sensor. After restricting the heating of the refrigerant by the heating medium, the operation of the compressor is stopped when the refrigerant pressure detected by the pressure detecting means drops to a set pressure.

That is, when the refrigerant pressure is reduced due to the limitation of the heating of the refrigerant, the power required for driving the compressor is sufficiently small. Therefore, even if the operation of the compressor is stopped, the driving torque of the wheels is reduced. There is no danger of the vehicle slipping because it increases only slightly.

The invention according to claim 8 is a compressor driven by the shaft output of the engine and compresses and sends out the refrigerant vapor, and the heat of the refrigerant vapor sent from the compressor is blown into the vehicle interior by the blowing means. An indoor heat exchanger that radiates heat to air, expansion means for evaporating a part of the refrigerant condensed by the indoor heat exchanger, and a heating medium supplied by the heating medium and passed through the expansion means by the heating medium. An air conditioner for a heat pump heating type vehicle, comprising an outdoor heat exchanger for heating, and further provided with an air volume operation unit for adjusting the air volume of the air blowing unit in the vehicle compartment, the pressure of the refrigerant sent from the compressor is reduced. A pressure detection unit for detecting, and an air volume per unit time when the air volume operation unit is operated such that an air volume of the air blowing unit is reduced to a predetermined amount or more. Air volume control means for controlling the operation of the air blowing means so that the lower volume is equal to or less than a predetermined value; and heating of the refrigerant by the heating medium when the refrigerant pressure detected by the pressure detection means rises to a set pressure. And heating limiting means for limiting the heating amount to be reduced or zero.

When the occupant operates the air volume operation means to rapidly reduce the flow rate of the air-conditioning air, the heat radiation capacity of the indoor heat exchanger sharply decreases, while the refrigerant flows into the outdoor heat exchanger. Continue to take away heat from. For this reason, the specific enthalpy of the refrigerant rapidly rises and the pressure of the refrigerant rises sharply. However, in the present invention, a sudden decrease in the air volume is prevented, so that a sudden rise in the refrigerant pressure can be avoided. Then, since the heating of the refrigerant is limited when the refrigerant pressure rises to the set pressure, the refrigerant pressure decreases,
Problems such as breakage of equipment constituting the refrigeration cycle can be avoided.

According to a ninth aspect of the present invention, in the vehicle air conditioner according to any one of the first to eighth aspects, the heating of the refrigerant by the heating medium is restricted by the outdoor heat exchange. It is performed by stopping the supply of the heating medium to the vessel.

By stopping the supply of the heating medium, the refrigerant is not heated in the outdoor heat exchanger, and the specific enthalpy of the refrigerant is reduced.

According to a tenth aspect of the present invention, in the vehicle air conditioner according to any one of the first to ninth aspects, the heating medium is engine cooling water.

That is, if the vehicle has a water-cooled engine, the engine cooling water can be used as a medium for heating the refrigerant.

According to an eleventh aspect of the present invention, in the vehicle air conditioner according to the second, fourth or fifth aspect, the operation of the compressor is restricted by stopping the operation of the compressor. There is a feature.

That is, by stopping the operation of the compressor, the work becomes zero and the refrigerant pressure decreases.

[0034]

As described above, in a heat pump heating air conditioner including a compressor driven by an engine of a vehicle and an outdoor heat exchanger for heating the refrigerant with a heating medium, the refrigerant sent from the compressor is removed. Since pressure detection means for detecting the pressure and means for restricting the heating of the refrigerant by the heating medium when the detected refrigerant pressure rises to the set pressure are provided, the work amount of the compressor due to rapid acceleration of the engine or the like is provided. Even if the refrigeration cycle increases, the specific enthalpy of the refrigerant decreases and the refrigerant pressure decreases, which is advantageous in preventing damage to the equipment constituting the refrigeration cycle, and it is not necessary to immediately stop the compressor, and the driving torque of the wheels This is advantageous in avoiding problems such as occurrence of slip due to excessive rise of the pressure.

According to the invention, when the refrigerant pressure rises to the second set pressure higher than the first set pressure for the heating restriction, the operation of the compressor is restricted, and the running stability of the vehicle is improved. The refrigerant pressure can be quickly reduced by the restriction without adversely affecting the pressure.

Further, according to the invention, when the refrigerant pressure is reduced to the third set pressure lower than the first set pressure due to the refrigerant heating restriction, the heating restriction is released, thereby constituting a refrigeration cycle. The heating capacity can be restored without causing troubles such as breakage of the equipment.

Further, according to the invention, when the refrigerant pressure is reduced to the third set pressure lower than the first set pressure due to the refrigerant heating limitation and the compressor operation limitation, the heating limitation is released. In addition, the heating capacity can be restored without causing troubles such as breakage of equipment constituting the refrigeration cycle.

According to the invention, when the refrigerant pressure is reduced to the third set pressure lower than the first set pressure due to the heating restriction of the refrigerant, the operation of the compressor is limited. This is advantageous in reliably preventing the compressor or the like from malfunctioning and the vehicle from slipping.

When the operation switch of the air conditioner is switched from operation to stop, first, the heating of the refrigerant is restricted,
According to the invention in which the operation of the compressor is stopped after that, it is possible to avoid a situation in which the driving torque of the wheels suddenly rises due to the switch operation and the vehicle slips.

Further, when the air volume operation device is operated so that the air volume of the air blowing device decreases to a predetermined value or more, the operation of the blowing device is controlled so that the air volume reduction amount per unit time becomes equal to or less than a predetermined value. According to the invention in which the heating of the refrigerant is restricted when the refrigerant pressure rises to the set pressure, the refrigerant pressure is reduced by restricting the heating of the refrigerant while avoiding a sudden increase in the refrigerant pressure. Problems such as breakage can be avoided.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 -Hardware Configuration- In a heat pump heating type vehicle heating apparatus shown in FIG. 1, reference numeral 1 denotes an engine constituting a power plant of the vehicle. The output shaft of the engine 1 is equipped with an engine pulley 2, and drives a compressor pulley 4 via a belt 3. The compressor pulley 4 is connected to a compressor 6 via an electromagnetic clutch 5. The engine 1 and the outdoor heat exchanger 7 are connected by a supply hose 8 and a return hose 9, and the engine 8 and the outdoor heat exchanger 7 pass between the engine 1 and the outdoor heat exchanger 7 by the two hoses 8 and 9. Heating medium)
Is circulating.

Explaining the refrigeration cycle, the refrigerant is compressed by the compressor 6 to become a high-temperature high-pressure gas.
It is sent to the indoor heat exchanger 11. In the indoor heat exchanger 11, the refrigerant is cooled by the low-temperature air for air-conditioning to become a low-temperature, high-pressure gas, and sent to the throttle valve (expansion means) 12. The refrigerant is reduced in pressure by the throttle valve 12 through a narrow passage, and is sent to the outdoor heat exchanger 7 as a low-temperature low-pressure gas-liquid mixture. The refrigerant is heated by the high-temperature engine cooling water in the outdoor heat exchanger 7, turns into a high-temperature low-pressure gas, and returns to the compressor 6.

The throttle valve 12 is not always necessary, and the refrigerant pipe between the indoor heat exchanger 11 and the outdoor heat exchanger 7 may be made thinner and used instead. That is, the expansion means is constituted by the capillary tube.

The indoor heat exchanger 11 is interposed in an air conditioning duct 13 of the vehicle. A fan 15 driven by a blower motor 14 is provided upstream of the indoor heat exchanger 11 in the duct 13, and a heater core 16 is provided downstream of the indoor heat exchanger 11. A supply hose 17 branched from the supply hose 8 is connected to the heater core 16.
Is connected to the return hose 9 so as to heat the air-conditioning air with the engine cooling water.

That is, the air for air conditioning is sent to the indoor heat exchanger 11 by the action of the fan 15,
6, the air is blown out from a plurality of outlets in the passenger compartment toward the inside of the window, the feet of the occupant, and the upper body of the occupant by a distribution device (not shown). In this case, heating by the heater core 16 becomes main heating, and heating by the refrigeration cycle becomes auxiliary heating.

The refrigerant pipe 19 extending from the discharge side of the compressor 6 to the indoor heat exchanger is provided with a pressure sensor (pressure detecting means) 21 for detecting the pressure of the refrigerant. The supply hose 8 extending from the engine 1 to the outdoor heat exchanger 7 is provided with an electromagnetic on-off valve 22 for shutting off the supply of engine cooling water to the outdoor heat exchanger 7. The supply hose 17 extending to the above-described heater core 16 branches from the upstream side of the electromagnetic on-off valve 22.

The electromagnetic clutch 5 and the electromagnetic on-off valve 22
The operation of is controlled by the controller 23 based on the pressure detected by the pressure sensor 21. For this purpose, a detection signal of the pressure sensor 21 is given to the controller 23,
A compressor switch 24 for operating the compressor 6 to start and stop the compressor 6 and a solenoid on-off valve 2 from the controller 23
2 is provided with a control signal. Further, a signal of the air volume operation means 25 for adjusting the air volume of the fan 15 is given to the blower motor 14. The air volume operation means 25 is provided in the vehicle compartment, and switches the air volume in stages.

-Control Configuration- When the refrigerant pressure P detected by the pressure sensor 21 rises to the first set pressure P1, the controller 23 closes the electromagnetic valve 22 to limit the heating of the refrigerant. Means, when the refrigerant pressure P rises to a second set pressure P2 higher than the first set pressure P1,
Operation limiting means for limiting the operation of the compressor 6 by interrupting the electromagnetic clutch 5.

The control flow is shown in FIG. That is, when the detection signal of the pressure sensor 21 is read, and the refrigerant pressure P rises to the first set pressure P1, the electromagnetic on-off valve 22 is closed, and the heating of the refrigerant by the outdoor heat exchanger 7 is restricted (step). S1 to S3). When the refrigerant pressure P rises to the second set pressure P2 higher than the first set pressure P1, the electromagnetic clutch 5 is disconnected and the operation of the compressor 6 is restricted (steps S4 and S5). Thereafter, when the refrigerant pressure P decreases to a third set pressure P3 lower than the first set pressure P1, the electromagnetic clutch 5 is connected, the operation restriction of the compressor 6 is released, and the electromagnetic on-off valve 22 is opened. The restriction on the heating of the refrigerant is released (step S6).
~ S8). Further, the refrigerant pressure P does not increase to the second set pressure P2 after the above-described refrigerant heating restriction, and the third set pressure P3
When the temperature has decreased to (1), the heating restriction is released (steps S3 → S4 → S9 → S10).

FIG. 3 shows an example of the change over time of the refrigerant pressure. In this example, the operation of the air conditioner starts when the operation of the engine 1 is started (the connection of the electromagnetic clutch 5 and the electromagnetic on-off valve 22 is opened), and the refrigerant pressure P increases with an increase in the engine speed and an increase in the temperature of the engine coolant. Is rising. If the engine speed is in the middle rotation range and there is no large change, the refrigerant pressure is equal to the first set pressure P1 (for example, 3.0 MPa
Near).

However, for example, when the engine 1 is rapidly accelerated without the shift change of the transmission at the time Ta and the refrigerant pressure P rises and rises to the first set pressure P1 at the time Tb, the electromagnetic switching valve 22 Is closed, and the supply of the engine cooling water to the outdoor heat exchanger 7 is stopped. As a result, the specific enthalpy of the refrigerant decreases, and at time Tc, the refrigerant pressure P increases to the third set pressure P3 (for example, 2.30).
0 MPa). Therefore, troubles such as breakage of equipment constituting the refrigeration cycle are avoided. Then, when the refrigerant pressure P drops to the third set pressure P3, the solenoid on-off valve 22 is connected again, and the refrigerant is heated by the engine cooling water, so that the refrigerant pressure P is recovered. Heating is ensured.

FIG. 4 shows another example of the temporal change of the refrigerant pressure. This is at the time Ta, for example, when there is a sudden acceleration operation of the engine 1 accompanied by a shift change. In this case, since the acceleration becomes even steeper than in the example of FIG. 3, the refrigerant pressure P becomes equal to the first set pressure P1 at time Tb.
, And continues to rise even when the electromagnetic on-off valve 22 is closed, and reaches the second set pressure P2 at time Tc. This allows
The electromagnetic clutch 5 is shut off, the compressor 6 stops, and the refrigerant pressure P decreases. Therefore, troubles such as breakage of equipment constituting the refrigeration cycle are avoided. When the refrigerant pressure decreases to the third set pressure P3 at time Td, the electromagnetic clutch 5 is connected, the electromagnetic on-off valve 22 is opened, and the refrigerant pressure P rises again to secure heating. When the electromagnetic clutch 5 is disengaged at the time Tc, the driving torque of the wheels increases. However, when the rapid acceleration operation as in the present embodiment is performed, the road surface friction coefficient is usually high, so Does not occur.

<Second Embodiment> The hardware configuration of this embodiment is the same as that of the first embodiment. The control flow is shown in FIG. That is, when the detection signal of the pressure sensor 21 is read, and the refrigerant pressure P rises to the first set pressure P1, the electromagnetic on-off valve 22 is closed, and the heating of the refrigerant by the outdoor heat exchanger 7 is restricted (step). S11 to S13). When the refrigerant pressure P rises to the second set pressure P2 higher than the first set pressure P1, the electromagnetic clutch 5 is disconnected and the operation of the compressor 6 is restricted (steps S14, S15).
On the other hand, when the refrigerant pressure P decreases to the third set pressure P3 lower than the first set pressure P1 due to the heating restriction of the refrigerant,
The operation of the compressor 6 is restricted by disconnecting the electromagnetic clutch 5 (steps S13 → S14 → S16 → S1).
5).

FIG. 6 shows an example of the change over time of the refrigerant pressure P. Up to the point where the engine 1 is accelerated at the time Ta and the solenoid on-off valve 22 is closed at the time Tb to reduce the refrigerant pressure P, the operation is the same as that of the first embodiment shown in FIG. However, in this example, the refrigerant pressure P is equal to the third set pressure P3.
(For example, 1.0 MPa), the electromagnetic clutch 5 is cut off and the operation of the compressor 6 is stopped. That is, in this case, early heating of the vehicle compartment is achieved by the refrigerant pressure P rising to the first set pressure P1, and after that, vehicle heating can be ensured by main heating by the heater core 16. Originally, the auxiliary heating by the refrigeration cycle is canceled when the refrigerant pressure P decreases to the third set pressure P3.

It is preferable that the third set pressure P3 be as low as possible in order to prevent slipping on a frozen road surface. However, if the third set pressure P3 is too low, the third set pressure P3 can be maintained at any time when the temperature is high. It does not drop to P3.
Therefore, HFCs widely used in automotive air conditioners
In consideration of the saturation pressure characteristics of the refrigerant 134a, it is preferable that the third set pressure P3 is set to around 1.0 MPa.

FIG. 7 shows the change over time in the refrigerant pressure when the engine 1 is suddenly accelerated with a shift change. In this case, when the refrigerant pressure P rises to the second set pressure at the time Tc, the electromagnetic clutch 5 is disengaged, and the refrigerant pressure P is decreasing. At time Td, the refrigerant pressure P has decreased to the third set pressure P3. At this time, the connection of the electromagnetic clutch 5 and the switching of the electromagnetic on-off valve 22 from closed to open are not performed.

<Embodiment 3> The hardware configuration of the present embodiment is shown in FIG. 8, and a signal of a compressor switch 24 operated by an occupant and a signal of a pressure sensor 21 are given to a controller 23, and the electromagnetic clutch 5 and the electromagnetic On-off valve 22
The operation is controlled in the same manner as in the first embodiment.

When the compressor switch 24 is switched from operation to stop, the controller 23 limits the heating of the refrigerant by closing the solenoid on-off valve 22 while continuing to operate the compressor 6, and thereafter, the refrigerant pressure P Is provided with air-conditioning stop control means for stopping the operation of the compressor 6 when the pressure drops to the set pressure P3.

The control flow is shown in FIG. That is, the detection signal of the pressure sensor 21 and the on / off signal of the compressor switch 24 are read, and if the compressor switch 24 is off, the electromagnetic on-off valve 22 is closed and the refrigerant is heated by the outdoor heat exchanger 7. It is restricted (steps S21 to S23). Refrigerant pressure P is equal to set pressure P
3, the electromagnetic clutch 5 is disconnected, and the operation of the compressor 3 is restricted (steps S24 and S2).
5).

FIG. 10 shows the change over time of the refrigerant pressure P. When the compressor switch 24 is turned off at the time Ta, the solenoid on-off valve 22 is closed and the refrigerant pressure P
Decrease. This refrigerant pressure P is equal to the set pressure (for example, 1.0
When the pressure drops to (MPa), the electromagnetic clutch 5 is disconnected, and the refrigerant pressure P drops sharply. Therefore, even if the compressor switch 24 is turned off by the occupant, the compressor 6 does not stop immediately, so that the driving torque of the wheels does not rise sharply, and the slip is prevented. When the compressor 6 is stopped after the refrigerant pressure P has decreased, the power required for driving the compressor 3 has already been reduced, so that there is no sharp increase in the driving torque of the wheels.

<Embodiment 4> The hardware configuration of this embodiment is shown in FIG. 11, and the signals of the air volume operation means 25, the compressor switch 24 and the pressure sensor 21 are given to the control means, and the electromagnetic clutch 5, electromagnetic The operation of the on-off valve 22 and the blower motor 14 is controlled, and the other components are the same as those of the first embodiment.

The controller 23 operates the blower motor 14 such that when the air volume operation means 25 is operated so that the air volume of the fan 15 decreases to a predetermined value or more, the air volume reduction amount per unit time becomes equal to or less than a predetermined value. Air flow control means for controlling the operation and heating limiting means for limiting the heating of the refrigerant by closing the electromagnetic on-off valve 22 when the refrigerant pressure rises to the P set pressure P1.

FIG. 12 shows the control flow. That is, when the signals of the air volume operation unit 25, the pressure sensor 21, and the compressor switch 24 are read and the air volume operation unit 25 is operated so that the air volume is reduced to a predetermined amount or more, the air volume reduction rate (per unit time) (Step S31 to S31).
S33). When the refrigerant pressure P rises to the set pressure P1, the electromagnetic on-off valve 22 is closed, and the heating of the refrigerant by the outdoor heat exchanger 7 is restricted (steps S34, S35).

FIG. 13 shows an example of limiting the rate of decrease in the air flow rate. This is because the terminal voltage of the blower motor 14 is continuously reduced when the air flow rate operation means 25 is operated so that the air flow rate decreases to a predetermined amount or more. In this example, Such control can be performed by using, for example, a power transistor. FIG. 14 shows a temporal change of the refrigerant pressure P in this case. When the air volume operation means 25 is operated so as to reduce the air volume to a predetermined amount or more at the time Ta, the refrigerant pressure P continuously increases as the air volume continuously decreases. At time Te, the refrigerant pressure P reaches the set pressure P
When the pressure rises to 1, the solenoid on-off valve 22 closes and the refrigerant pressure P
Is declining.

The characteristics shown by the dashed lines in FIGS. 13 and 14 are obtained when the rate of decrease of the air volume is not controlled. In this case, the refrigerant pressure P rises rapidly at the time Ta, reaches the second set pressure P2, and the electromagnetic clutch 5 is disconnected. Therefore,
Damage to equipment due to sudden increase in refrigerant pressure P, electromagnetic clutch 5
There is a problem that the wheel drive torque suddenly rises due to the interruption of
This is no longer the case in the present embodiment.

FIG. 15 shows another restriction example of the air flow rate reduction rate, in which the terminal voltage of the blower motor is reduced stepwise. This control can be performed by combining a plurality of resistors and a relay. FIG. 16 shows a temporal change of the refrigerant pressure P in that case. When the air volume operation means 25 is operated to reduce the air volume to a predetermined amount or more at the time Ta, the refrigerant pressure P increases stepwise as the air volume decreases stepwise. And
When the refrigerant pressure P rises to the set pressure P1 at the time Te, the electromagnetic on-off valve 22 closes and the refrigerant pressure P decreases.

The rate of decrease of the air flow may be limited by controlling the decrease in the output of the blower motor 14 itself.

[Brief description of the drawings]

FIG. 1 is a diagram showing a hardware configuration of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a flowchart of control of the embodiment.

FIG. 3 is a graph showing an example of the change over time of the refrigerant pressure in the same embodiment.

FIG. 4 is a graph showing another example of the temporal change of the refrigerant pressure in the same embodiment.

FIG. 5 is a flowchart of control according to a second embodiment of the present invention.

FIG. 6 is a graph showing an example of the change over time of the refrigerant pressure in the same embodiment.

FIG. 7 is a graph showing another example of a temporal change of the refrigerant pressure in the same embodiment.

FIG. 8 is a diagram showing a hardware configuration of an air conditioner according to Embodiment 3 of the present invention.

FIG. 9 is a flowchart of control of the same embodiment.

FIG. 10 is a graph showing an example of the change over time of the refrigerant pressure in the same embodiment.

FIG. 11 is a diagram illustrating a hardware configuration of an air conditioner according to a fourth embodiment of the present invention.

FIG. 12 is a flowchart of control of the same embodiment.

FIG. 13 is a graph showing an example of a temporal change of a blower motor terminal voltage of the same embodiment.

FIG. 14 is a graph showing an example of the change over time of the refrigerant pressure in the same embodiment.

FIG. 15 is a graph showing another example of the temporal change of the blower motor terminal voltage of the same embodiment.

FIG. 16 is a graph showing another example of the temporal change of the refrigerant pressure of the same embodiment.

[Explanation of symbols]

 Reference Signs List 1 engine 6 compressor 5 electromagnetic clutch 7 outdoor heat exchanger 11 indoor heat exchanger 12 throttle valve (expansion means) 19 refrigerant pipe 14 blower motor 15 fan 21 pressure switch 22 electromagnetic on-off valve 23 controller 24 compressor switch (operation switch) 25 Air volume operation means

Claims (11)

[Claims] A compressor driven by an axial output of an engine to compress and send a refrigerant vapor; an indoor heat exchanger for radiating heat of the refrigerant vapor sent from the compressor into a vehicle interior; A heat pump heating type including an expansion unit that evaporates a part of the refrigerant condensed by the heat exchanger, and an outdoor heat exchanger that is supplied with a heating medium and heats the refrigerant that has passed through the expansion unit with the heating medium. In the air conditioner of the vehicle, a pressure detecting means for detecting a pressure of the refrigerant sent from the compressor, and when the refrigerant pressure detected by the pressure detecting means rises to a set pressure, the refrigerant is cooled by the heating medium. An air conditioner for a vehicle, comprising: heating limiting means for limiting heating so that the heating amount is reduced or becomes zero. 2. The vehicle air conditioner according to claim 1, further comprising a second set pressure at which the refrigerant pressure detected by the pressure detection means is higher than a first set pressure at which the heating restriction means operates. An air conditioner for a vehicle, comprising an operation restricting means for restricting the operation of the compressor so that the amount of work thereof is reduced or becomes zero when the compressor rises. 3. The vehicle air conditioner according to claim 1, wherein the heating restriction unit restricts heating of the refrigerant by the heating medium, and then detects a refrigerant pressure detected by the pressure detection unit, An air conditioner for a vehicle, wherein the heating restriction is released when the pressure is reduced to a third setting pressure lower than the first setting pressure at which the heating restriction is to be performed. 4. The air conditioner for a vehicle according to claim 2, wherein the heating restriction means for the refrigerant and the operation restriction means for the compressor are provided after the operation of the compressor is restricted.
When the refrigerant pressure detected by the pressure detecting means drops to a third set pressure lower than the first set pressure, the heating restriction and the compressor operation restriction are released respectively. . 5. The vehicle air conditioner according to claim 1, further comprising: a refrigerant pressure detected by the pressure detection unit after the refrigerant is restricted by the heating restriction unit. When the pressure is reduced to a third set pressure lower than the first set pressure to be limited, the compressor is provided with operation limiting means for limiting the operation of the compressor so that the work amount is reduced or becomes zero. Vehicle air conditioner. 6. A compressor driven by an axial output of an engine to compress and send refrigerant vapor, an indoor heat exchanger for radiating heat of the refrigerant vapor sent from the compressor to a vehicle interior, and an indoor heat exchanger. An expansion means for evaporating a part of the refrigerant condensed by the heat exchanger; an outdoor heat exchanger supplied with a heating medium and heating the refrigerant having passed through the expansion means with the heating medium; An air conditioner for a heat pump heating type vehicle provided with an operation switch for operating and stopping the air conditioner, wherein when the operation switch is switched from operation to stop, the operation of the compressor is continued. Limit the heating of the refrigerant by the heating medium so that the amount of heating is reduced or becomes zero, and then the operation of the compressor is stopped. Air-conditioning system of a vehicle, characterized by comprising a mediation stop control means. 7. The air conditioner for a vehicle according to claim 6, further comprising a pressure detecting unit that detects a pressure of the refrigerant sent from the compressor, wherein the air conditioning stop control unit detects the pressure of the refrigerant by the heating medium. An air conditioner for a vehicle, wherein the operation of the compressor is stopped when the refrigerant pressure detected by the pressure detecting means drops to a set pressure after the heating is restricted. 8. A compressor driven by an axial output of an engine to compress and send refrigerant vapor, and an indoor side for radiating heat of the refrigerant vapor sent from the compressor to air blown into a vehicle interior by a blowing means. A heat exchanger, expansion means for evaporating a part of the refrigerant condensed by the indoor heat exchanger, and outdoor heat exchange for supplying a heating medium and heating the refrigerant passing through the expansion means with the heating medium. In a heat pump heating type air conditioner for a vehicle, further comprising an air volume operation means for adjusting the air volume of the air blowing means in the cabin, a pressure detecting means for detecting a pressure of a refrigerant sent from the compressor, When the air volume operation device is operated so that the air volume of the air blowing device is reduced to a predetermined value or more, the air volume reduction amount per unit time becomes equal to or less than a predetermined value. Air volume control means for controlling the operation of the air blowing means, and when the refrigerant pressure detected by the pressure detection means rises to a set pressure, the heating amount of the refrigerant by the heating medium is reduced. Or a heating limiting means for limiting the temperature to zero. 9. The air conditioner for a vehicle according to claim 1, wherein the heating of the refrigerant by the heating medium is restricted by the heating medium to the outdoor heat exchanger. An air conditioner for a vehicle, which is performed by stopping supply of air. 10. A vehicle air conditioner according to claim 1, wherein the heating medium is engine cooling water. 11. The air conditioner for a vehicle according to claim 2, wherein the operation of the compressor is restricted by stopping the operation of the compressor. Vehicle air conditioner.