JP2003159930A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively control the operation of a plurality of auxiliary heating means and improve the fuel consumption of the engine of a vehicle without exercising a bad effect on the temperature feeling of an occupant in using an air conditioner for a vehicle comprising the auxiliary heating means that is a combination of a hot gas heater cycle and an electric heater. <P>SOLUTION: In steps S140 and S160, a heating load is measured based on the temperature of the fresh air. When the temperature of the fresh air is lower than a first prescribed value T1 and the heating load is large, the hot gas heater cycle and the electric heater are actuated simultaneously in a step S130. When the heating load decreases, the electric heater is stopped first, leaving the hot gas heater cycle operating alone in a step S150. Then, upon further decrease of the heating load, the hot gas heater cycle is also stopped in a step S170. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a compressor discharge gas refrigerant (hot gas) for indoor heat exchanger (evaporator) during heating.
The present invention relates to a vehicular air conditioner that exhibits a hot gas heating function by using the indoor heat exchanger as a radiator of gas refrigerant by directly introducing it into the air conditioner.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner, hot water (engine cooling water) is circulated in a heating heat exchanger during heating in winter,
In this heating heat exchanger, hot water is used as a heat source to heat the conditioned air. In this case, when the temperature of the hot water is low, the temperature of the air blown into the vehicle interior may decrease and the required heating capacity may not be obtained.

In view of this, Japanese Patent Application Laid-Open No. 5-223357 proposes a refrigeration cycle apparatus which can exhibit a heating function by a hot gas heater cycle. In this conventional device, when the hot water temperature is lower than a predetermined temperature, such as when the engine is started, a hot gas heater cycle is formed in which the compressor discharge gas refrigerant (hot gas) bypasses the condenser and is introduced into the evaporator. The evaporator radiates heat from the gas refrigerant to the conditioned air so that it can perform the heating function. That is, in the above conventional apparatus, the evaporator, which is one indoor heat exchanger installed in the air conditioning case, is switched and used as the cooler in the cooling mode and the radiator in the heating mode.

[0004]

By the way, when the outside temperature is −
In cold weather where the temperature drops to 10 ° C. or less, the heating capacity may still be insufficient even if the heating function is exhibited by the hot gas heater cycle. Therefore, the present inventors
We are developing a vehicle air conditioner that combines a hot gas heater cycle with an electric heater as an auxiliary heating means.

Therefore, an object of the present invention is to provide a vehicle air conditioner in which a hot gas heater cycle and an electric heater are combined as auxiliary heating means, and the operation of a plurality of auxiliary heating means can be favorably performed without adversely affecting the passenger's sense of temperature. To improve the fuel efficiency of the vehicle engine.

[0006]

In order to achieve the above object, in the invention according to claim 1, the vehicle engine (12) is provided.
Having a compressor (10) of a refrigeration cycle driven by a hot gas heater for directly introducing a discharge gas refrigerant from the compressor (10) into an indoor heat exchanger (18) to heat air blown into a vehicle interior. The cycle (H), the electric heater (30) for heating the air blown into the vehicle interior, and the determination means (S140, S160) for determining the heating heat load are provided, and the determination means (S140, S160) makes the determination. When the heating heat load is large, both the hot gas heater cycle (H) and the electric heater (30) are activated, and when the heating heat load decreases, the electric heater (30) is stopped first to start the hot gas heater cycle (H). When operated alone and then the heating heat load is further reduced, the hot gas heater cycle (H)
It is characterized by stopping.

According to this, when the outside air temperature is very low and the heating heat load is large, both the hot gas heater cycle (H) and the electric heater (30) are operated to raise the temperature of the air blown into the passenger compartment, and when it is extremely cold. It is possible to improve the heating performance of the vehicle interior. Moreover, the hot gas heater cycle (H)
And the electric heater (30) are not simultaneously operated and stopped, the electric heater (30) is stopped first by reducing the heating heat load, and then the hot gas heater cycle (H) is stopped. ) And the electric heater (30) when the operation is switched, it is possible to suppress the variation in the temperature of the air blown into the vehicle compartment. Therefore, it is possible to reduce the change in occupant's thermal sensation associated with this operation switching.

Further, as the heating heat load decreases, the electric heater (30) of the hot gas heater cycle (H) and the electric heater (30) is stopped first, which brings the following advantage.

That is, when the electric heater (30) which consumes a large amount of power is activated, the power generation load of the vehicle-mounted generator (37) becomes very large. Therefore, in order to improve the power generation capacity of the vehicle-mounted generator (37), the vehicle engine It becomes necessary to increase the idle speed of (12) higher than when the hot gas heater cycle (H) is operating (that is, when the compressor is operating).

In the invention described in claim 1, paying attention to this point, since the electric heater (30) is stopped first as the heating heat load decreases, the hot gas heater cycle (H) precedes. Compared with the case of stopping, the period for increasing the idle speed of the vehicle engine (12) can be shortened,
The fuel economy of the vehicle engine (12) can be improved. Also, by reducing the idle speed of the vehicle engine (12),
It is possible to reduce noise, vibration, etc. associated with the operation of the vehicle engine (12).

As in the invention described in claim 2, the heating heat load can be specifically determined based on the outside air temperature.

As in the third aspect of the invention, the heating heat load may be specifically determined based on the inside air temperature.

As in the invention described in claim 4, the heating heat load may be specifically determined based on the temperature of the air blown from the indoor heat exchanger (18).

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, hot water is introduced from the vehicle engine (12), and the hot water is used as a heat source to heat air blown into the vehicle interior. Equipped with a heating heat exchanger (24)
Hot gas heater cycle (H) and electric heater (3
0) is characterized in that it constitutes an auxiliary heating means for the hot water heating heat exchanger (24).

As a result, when the heating heat load is large,
For the main heating action by the hot water heating heat exchanger (24),
Hot gas heater cycle (H) and electric heater (30)
By combining the auxiliary heating action by, the vehicle interior heating performance can be quickly started up.

In a sixth aspect of the present invention, a compressor (1) of a refrigeration cycle driven by a vehicle engine (12).
0), which introduces the discharge gas refrigerant from the compressor (10) directly into the indoor heat exchanger (18) to heat the air blown into the vehicle interior, and the vehicle engine (12). ) From which hot water is introduced to heat air blown into the vehicle compartment using the hot water as a heat source, an electric heater (30) for heating air blown into the vehicle compartment, and a heating And a hot gas heater cycle (H) when the heating capacity determined by the determining means (S140, S160) is small. When the heater (30) is operated together and the heating capacity is increased, the electric heater (30) is stopped first to operate the hot gas heater cycle (H) alone, and when the heating capacity is further increased, the hot Characterized by stopping the gas heater cycle (H).

As a result, the heat exchanger for hot water heating (2
Even when the heating capacity of 4) is small, the heat exchanger for heating (2
By combining the main heating function of 4) with the auxiliary heating function of the hot gas heater cycle (H) and the electric heater (30), it is possible to quickly raise the heating performance of the passenger compartment.

Further, the electric heater (30) is stopped first due to an increase in heating capacity of the hot water heating heat exchanger (24),
After that, since the hot gas heater cycle (H) is stopped, the hot gas heater cycle (H) and the electric heater (3
It is possible to suppress the variation in the temperature of the air blown into the vehicle compartment at the time of the operation switching of 0), and therefore, it is possible to reduce the change in the occupant's thermal sensation accompanying the operation switching.

Further, the electric heater (30) is stopped first,
Since the hot gas heater cycle (H) is stopped after that, the fuel consumption of the vehicle engine (12) can be improved and the noise, vibration, etc. accompanying the operation of the vehicle engine (12) can be reduced for the same reason as in claim 1. .

According to the invention described in claim 7, claim 6
In, the heating capacity can be specifically determined based on the temperature of the hot water.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 illustrates an overall configuration of a vehicle air conditioner according to a first embodiment of the present invention. The compressor 10 is belt-driven by a water-cooled vehicle engine 12 via an electromagnetic clutch 11,
For example, it is composed of a fixed capacity swash plate compressor. The vehicle engine 12 drives not only the compressor 10 but also auxiliary equipment such as a generator 37 for charging the battery. The generator 37 is a three-phase AC generator generally called an alternator.

The discharge side of the compressor 10 is connected to a condenser 14 via a cooling solenoid valve 13, and the outlet side of the condenser 14 is a liquid receiver 15 for separating the gas-liquid refrigerant and storing the liquid refrigerant. Connected. The condenser 14 is an outdoor heat exchanger that is disposed in the vehicle engine room together with the compressor 10 and the like and exchanges heat with the outside air (cooling air) blown by the electric cooling fan 14a.

The outlet side of the liquid receiver 15 is connected to a temperature type expansion valve 16 which constitutes a pressure reducing device for cooling. The outlet side of the temperature type expansion valve 16 is connected to the evaporator 1 via a check valve 17.
8 is connected. The outlet side of the evaporator 18 is connected to the suction side of the compressor 10 via an accumulator 19.

From the discharge side of the compressor 10 described above, the cooling solenoid valve 13 → condenser 14 → liquid receiver 15 → thermal expansion valve 16
-> Check valve 17-> Evaporator 18-> The closed circuit that returns to the suction side of the compressor 10 via the accumulator 19 constitutes a normal refrigeration cycle C for cooling.

As is well known, the temperature type expansion valve 16 adjusts the valve opening degree (refrigerant flow rate) so that the superheat degree of the refrigerant at the outlet of the evaporator 18 is maintained at a predetermined value during the normal refrigeration cycle operation (in the cooling mode). To do. The accumulator 19 separates the gas-liquid of the refrigerant to store the liquid refrigerant, and the gas refrigerant to the compressor 1
At the same time, the refrigerant is sucked into 0, and a small amount of liquid refrigerant in which the oil accumulated near the bottom is dissolved is mixed with the gas refrigerant and sucked into the compressor 10.

On the other hand, a hot gas bypass passage 20 for bypassing the condenser 14 and the like is provided between the discharge side of the compressor 10 and the inlet side of the evaporator 18, and this bypass passage 2
At 0, a heating solenoid valve 21 and a throttle 21a are provided in series. The diaphragm 21a constitutes a heating decompression device, and can be composed of a fixed diaphragm such as an orifice or a capillary tube. A hot gas heater cycle H for heating is constituted by a closed circuit that returns from the discharge side of the compressor 10 to the intake side of the compressor 10 via the heating electromagnetic valve 21 → throttle 21a → evaporator 18 → accumulator 19.

The air conditioning case 22 of the vehicle air conditioner constitutes an air passage through which air flows toward the passenger compartment, and the air is blown in the air conditioning case 22 by an electric air conditioning blower 23. Although the air-conditioning blower 23 is shown as an axial flow type for simplification of illustration, it is actually a centrifugal blower having a centrifugal fan, and this air-conditioning blower 23 is a blower motor 23a controlled by a blower drive circuit. Is driven to rotate. The amount of air blown by the blower 23 of the present embodiment can be switched continuously or stepwise by adjusting the blower control voltage applied to the blower motor 23a.

Further, on the suction side of the air conditioner blower 23, an outside air intake port 70 for sucking in outside air (hereinafter referred to as outside air) and an inside air intake port 71 for sucking inside air (hereinafter referred to as inside air). , And an inside / outside air switching door 72 are provided. The inside / outside air switching door 72 is driven by an actuator such as a servomotor via a link mechanism (not shown), and at least the outside air mode for sucking the outside air from the outside air suction port 70 and the inside air mode for sucking the inside air from the inside air suction port 71 are used. An inside / outside air switching means for switching is configured.

The evaporator 18 is an indoor heat exchanger installed in the air conditioning case 22, and in the cooling mode, the refrigerant circulates by the refrigeration cycle C for cooling, and the evaporator 18 air-conditions by the refrigerant evaporation (heat absorption). The blown air of the blower 23 is cooled. Further, in the heating mode, the evaporator 18 serves as a radiator because the high-temperature refrigerant gas (hot gas) from the hot gas bypass passage 20 flows in to heat the air.

In the air conditioning case 22, on the air downstream side of the evaporator 18, there is provided a hot water heating heat exchanger 24 for heating the blown air using hot water (engine cooling water) from the vehicle engine 12 as a heat source. There is. The hot water circuit to the heat exchanger 24 for heating is provided with a hot water valve 25 for controlling the flow of hot water.

An electric heater 30 is provided in the air conditioning case 22 on the air downstream side of the heating heat exchanger 24. The electric heater 30 is formed in a shape having an air passage passage through which the blown air in the air conditioning case 22 passes, for example, a honeycomb shape, and can heat all the blown air in the air conditioning case 22.

By the way, a hot water heating heat exchanger 24
Serves as a main heating means for heating the interior of the vehicle, while the hot gas heater cycle H and the electric heater 30 constitute an auxiliary heating means.

On the other hand, on the most downstream side of the air in the air conditioning case 22, a defroster (DEF) outlet 3 for blowing out conditioned air (mainly warm air) toward the inner surface of the vehicle windshield.
1. Face (FACE) outlet 3 for blowing out conditioned air (mainly cold air) toward the face (upper body) of the vehicle occupant
2. Foot outlet for blowing out conditioned air (mainly warm air) toward the feet (lower body) of vehicle occupants 3
3, and a plurality of mode switching doors 34 to 36 that selectively open and close each of these outlets are rotatably provided. The mode switching doors 34 to 36 constitute a blowout mode switching means and are driven by an actuator such as a servo motor via a link mechanism (not shown).

Electronic control unit for air conditioning (hereinafter referred to as ECU)
Reference numeral 26 is composed of a microcomputer and its peripheral circuits, performs predetermined arithmetic processing according to a preset program, opens and closes the solenoid valves 13 and 21, and other electric devices (11, 14a, 23, 25, 30 etc.). ) Control the operation of.

FIG. 2 is an electric control block diagram of this embodiment. The ECU 26 has a water temperature sensor 27a for the vehicle engine 12, an outside air temperature sensor 27b, an evaporator outlet temperature sensor 27c serving as a temperature detecting means for the evaporator 18, Compressor discharge pressure (high pressure) pressure sensor 27d, inside air temperature sensor 27
e, a detection signal is input from a sensor group such as a solar radiation sensor 27f that detects the amount of solar radiation into the vehicle interior.

Further, an operation signal is input to the ECU 26 from the operation switch group 29 of the air conditioning operation panel 28 installed near the instrument panel of the passenger compartment. The following switches are installed as the operation switch group 29. The air conditioner switch 29a issues a command to start or stop the compressor 10 in the refrigeration cycle, and serves as a cooling switch that sets a cooling mode. The hot gas switch 29b sets a heating mode by the hot gas heater cycle H, and functions as a heating switch.

Further, on the air conditioning operation panel 28, a blowing mode selector switch 29c for switching the blowing mode of the air conditioning,
Temperature setting switch (temperature setting means) 29d for setting the temperature inside the vehicle to a desired temperature, blower switch 29e for instructing on / off and air volume switching of the blower 23, inside / outside air switching for instructing switching between the outside air mode and the inside air mode Switch 2
9f etc. are installed.

Next, the operation of the present embodiment having the above structure will be described. First, the operation of the refrigeration cycle portion will be described. In the cooling mode, the ECU 26 opens the cooling electromagnetic valve 13 and opens the heating electromagnetic valve 21. Therefore, when the electromagnetic clutch 11 is engaged and the compressor 10 is driven by the vehicle engine 12,
The gas refrigerant discharged from the compressor 10 is a cooling solenoid valve 13 in an open state.
And flows into the condenser 14.

In the condenser 14, the refrigerant is cooled and condensed by the outside air blown by the cooling fan 14a. Then, the refrigerant that has passed through the condenser 14 is separated into gas and liquid by the liquid receiver 15, and only the liquid refrigerant is decompressed by the thermal expansion valve 16 to be in a low temperature and low pressure gas-liquid two-phase state.

Next, the low-pressure refrigerant passes through the check valve 17, flows into the evaporator 18, and absorbs heat from the conditioned air blown by the blower 23 to be evaporated. The conditioned air cooled by the evaporator 18 is blown into the vehicle interior to cool the vehicle interior. Evaporator 1
The gas refrigerant evaporated in 8 is sucked into the compressor 10 via the accumulator 19 and compressed.

In the heating mode in the winter, the ECU 26 closes the cooling solenoid valve 13, and the heating solenoid valve 21 is closed.
Is opened and the hot gas bypass passage 20 is opened. Therefore, the high-temperature discharge gas refrigerant (superheated gas refrigerant) of the compressor 10 passes through the heating solenoid valve 21 in the open state and the throttle 21
After being decompressed by a, it flows into the evaporator 18.

At this time, the check valve 17 prevents the gas refrigerant from the hot gas bypass passage 20 from flowing to the temperature type expansion valve 16 side. Therefore, the refrigeration cycle is performed by the compressor 10
Discharge side → heating solenoid valve 21 → throttle 21a → evaporator 18
→ Accumulator 19 → Operates in a closed circuit (hot gas heater cycle H) that returns to the suction side of the compressor 10.

Then, the overheated gas refrigerant, which has been decompressed by the throttle 21a, radiates heat to the blown air in the evaporator 18 to heat the blown air. Here, the amount of heat released from the gas refrigerant in the evaporator 18 corresponds to the amount of compression work of the compressor 10. The gas refrigerant radiating heat in the evaporator 18 is sucked into the compressor 10 via the accumulator 19 and compressed.

Therefore, by blowing hot water through the hot water type heat exchanger 24 for heating through the hot water valve 25, the blown air heated by the evaporator 18 can be further heated by the heat exchanger 24. Then, if the electric heater 30 is energized, the warm air after passing through the heating heat exchanger 24 is heated by the electric heater 30.
As a result, it is possible to further heat, so that hot air with a higher temperature can be blown into the vehicle interior. The air conditioner blower 23 may be warmed up so as to operate with a low air volume when the temperature of the hot water of the engine 12 is low.

Next, a control example of the specific operation of the hot gas heater cycle H and the electric heater 30 during the heating in winter according to this embodiment will be described with reference to FIG. The control routine of FIG. 3 is started by, for example, starting the vehicle engine 12 (turning on an ignition switch (not shown) or the like), and in step S100, the sensors 27a to 27f and the operation switches 29a to 29f of the air conditioning operation panel 28. 29f
Read the signal from.

In the next step S110, it is determined whether or not the blower 23 is in the operating (ON) state. If the blower 23 is in the operating state, the process proceeds to step S120 and it is determined whether or not the hot gas switch 29b is turned on (ON). To do. If the hot gas switch 29b is turned on, step S1
At step 30, the heating mode is set by the hot gas heater cycle H, and at the same time, the electric heater 30 is energized to bring the electric heater 30 into an operating (ON) state.

More specifically, the setting of the heating mode in step S130 will be described. The electromagnetic clutch 11 is energized to bring the electromagnetic clutch 11 into the connected state, the compressor 10 is operated, and the cooling electromagnetic valve 13 is closed and heated. The solenoid valve 21 is opened. Thereby, in the refrigeration cycle, the refrigerant circulates by the hot gas heater cycle H, the evaporator 18 acts as a radiator, and the hot gas heating mode is set.

Next, in step S140, the outside temperature Tam
Is greater than or equal to a first predetermined value T1 (for example, −10 ° C.). Here, the outside air temperature Tam detected by the outside air temperature sensor 27b is information indicating the heating heat load, and when the outside air temperature Tam is lower than the first predetermined value T1, the heating heat load is large. Therefore, when the outside air temperature Tam <the first predetermined value T1, the simultaneous operation state of the hot gas heater cycle H and the electric heater 30 in step S130 is continued.

On the other hand, outside temperature Tam ≧ first predetermined value T
If it is 1, steps S140 to S15
0, the electric heater 30 is stopped (OFF),
Only the operation of the hot gas heater cycle H is continued. Next, in step S160, the outside air temperature Tam is the second predetermined value T.
Determine if it is 2 or more. Here, the second predetermined value T2 is a temperature higher than the first predetermined value T1 by a predetermined temperature, for example, 1
It is 0 ° C.

In this embodiment, when the determination in step S160 is NO, that is, when the first predetermined value T1 ≦ outside air temperature Tam <the second predetermined value T2, the heating heat load is in the intermediate state, The "hot gas heater cycle H single operation state" in S150 is continued.

Then, when the outside air temperature Tam rises above the second predetermined value T2, the heating heat load becomes small, and the determination in step S160 becomes YES and step S170.
Proceed to. In step S170, the energization of the electromagnetic clutch 11 is cut off to stop the compressor 10 and stop the operation of the hot gas heater cycle H, and at the same time, the electric heater 30 is stopped (OFF). As a result, the vehicle interior is heated only by the heating action of the hot water heat exchanger 24 that serves as the main heating means.

Incidentally, step S110 and step S
If the determination in 120 is NO, the hot gas heating mode is not required, so the flow proceeds to step S180, the electromagnetic clutch 11 is de-energized, and the hot gas heater cycle H is stopped.

As can be understood from the above description, when the outside air temperature Tam is lower than the first predetermined value T1, it means that the heating heat load becomes large and the hot gas heater cycle H is operated at the same time. Since the electric heater 30 is activated, the outside air of extremely low temperature of −10 ° C. or lower is heated by the hot gas in the evaporator 18, and then the blown air is further heated by the hot water heat exchanger 24 and the electric heater 30. Can be heated. Therefore, for the main heating operation of the hot water heat exchanger 24, the hot gas heater cycle H and the electric heater 30
Both of them can exert an auxiliary heating effect to raise the temperature of the air blown into the vehicle interior and improve the vehicle interior heating performance in extremely cold weather.

Then, the first predetermined value T1 ≦ outside temperature Tam <
When the second predetermined value T2, that is, when the heating heat load is in the intermediate state, the electric heater 30 is stopped and the hot gas heater cycle H is operated independently, so that the introduced outside air is hot gas in the evaporator 18. After being heated by the heat exchanger, it is heated by the hot water heat exchanger 24 and blown out into the passenger compartment.

Further, when the outside air temperature Tam ≧ the second predetermined value T2, that is, when the heating heat load is small, the hot gas heater cycle H is stopped in addition to the stop of the electric heater 30. As a result, the air blown into the vehicle compartment is heated only by the hot water heat exchanger 24 serving as the main heating means to heat the vehicle compartment.

In this way, in response to changes in the outside air temperature representing the heating heat load, the hot gas heater cycle H and the electric heater 30 are simultaneously operating, the hot gas heater cycle H is operating independently, and the hot gas heater cycle H is operating. Since the simultaneous stop state of both the electric heater 30 and the electric heater 30 is sequentially switched, the hot gas heater cycle H and the electric heater 3
Compared with the case where both 0 are simultaneously operated and stopped, it is possible to suppress the fluctuation of the temperature of the air blown into the vehicle compartment during the operation switching. Therefore, it is possible to reduce a change in occupant's thermal sensation caused by switching the operation of the auxiliary heating means, and it is possible to maintain a good heating feeling.

Further, since the electric heater 30 of the hot gas heater cycle H and the electric heater 30 is stopped first as the heating heat load is reduced, there are the following advantages.

That is, since the electric heater 30 consumes a large amount of power (for example, about 600 W), the power generation load of the generator 37 becomes very large when the electric heater 30 is operating. Therefore, when the electric heater 30 is operating, it is necessary to increase the idle speed of the vehicle engine 12 to about 1200 rpm in order to improve the power generation capacity of the generator 37. On the other hand, when the hot gas heater cycle H is operating (that is, when the compressor 10 is operating), the idle speed of the vehicle engine 12 may normally be about 800 rpm, and the engine idle speed when the electric heater is operating is hotter. It becomes higher than the engine idle speed during gas heater cycle operation.

In the present embodiment, paying attention to this point, the electric heater 30 is stopped first as the heating heat load decreases. As a result, the period in which the idling speed of the vehicle engine 12 is increased can be shortened and the fuel consumption of the vehicle engine 12 can be improved, as compared with the case where the hot gas heater cycle H is stopped first as the heating heat load decreases. Further, when the idle speed of the vehicle engine 12 is increased, it is disadvantageous in terms of noise and vibration, but according to the present embodiment, it is also advantageous in terms of reducing this noise, vibration and the like.

(Second Embodiment) In the first embodiment, the outside air temperature Tam detected by the outside air temperature sensor 27b is used as the information indicating the heating heat load, and the hot gas heater cycle H and the electric power are supplied based on the outside air temperature Tam. Although the operation of the heater 30 is controlled to be switched, in the second embodiment, the inside air temperature Tr detected by the inside air temperature sensor 27e is used as the information indicating the heating heat load, and the hot gas heater is used according to the change in the inside air temperature Tr. The cycle H and the operation of the electric heater 30 are switched and controlled.

FIG. 4 is a control flowchart according to the second embodiment. When the inside air temperature Tr <the first predetermined value T1 (for example, 0 ° C.) in step S140, it is determined that the heating heat load is large. Then, in step S130, the hot gas heater cycle H and the electric heater 30 are simultaneously operated.

When the first predetermined value T1 ≦ inside air temperature Tr <the second predetermined value T2 (for example, 10 ° C.), it is determined that the heating heat load is in the intermediate state, and the electric heater 30 is determined in step S150. Stop the hot gas heater cycle H
Operate by itself. When the inside air temperature Tr further rises and the inside air temperature Tr ≧ the second predetermined value T2, it is determined that the heating heat load is small, and in step S170, the electric heater 30 is stopped and the hot gas heater cycle is performed. H also stops. Therefore, the hot water heat exchanger 24, which constitutes the main heating means,
Only this will heat the air blown into the passenger compartment.

As described above, even if the operations of the hot gas heater cycle H and the electric heater 30 are controlled to be switched according to the change of the internal temperature Tr, the same effect as the first embodiment can be obtained.

(Third Embodiment) In the first embodiment, the outside air temperature Tam is used as the information indicating the heating heat load, and in the second embodiment, the inside air temperature T is used as the information indicating the heating heat load.
Although r is used, in the third embodiment, the evaporator outlet air temperature Te detected by the evaporator outlet temperature sensor 27c is used as the information indicating the heating heat load, and according to the change of the evaporator outlet air temperature Te. Hot gas heater cycle H
And the operation of the electric heater 30 is switched and controlled.

That is, since the outside air mode in which the outside air is introduced from the outside air introduction port 70 is usually selected in order to prevent the window glass of the vehicle from being fogged during heating in winter, the evaporator blown air temperature T
Although e has a temperature rise with respect to the outside air temperature by the amount heated by the evaporator 18, the air blown from the evaporator is sucked into the hot water heat exchanger 24 which is the main heating means, and therefore the air blown from the evaporator is discharged. The air temperature Te can be used as the heating heat load information.

FIG. 5 is a control flowchart according to the third embodiment. In step S140, when the evaporator outlet air temperature Te <the first predetermined value T1 (for example, 10 ° C.), the heating heat load is large. Judge that there is, step S
At 130, hot gas heater cycle H and electric heater 3
0 is activated at the same time.

When the first predetermined value T1 ≦ the evaporator outlet air temperature Te <the second predetermined value T2 (for example, 20 ° C.), it is determined that the heating heat load is in the intermediate state, and in step S150. The electric heater 30 is stopped and the hot gas heater cycle H is operated independently.

The evaporator outlet air temperature Te further rises,
In step S160, when the evaporator outlet air temperature Te ≧ the second predetermined value T2, it is determined that the heating heat load is small, and in step S170, the hot gas heater cycle H is stopped in addition to the stop of the electric heater 30. To do. Therefore,
The air blown into the vehicle compartment is heated only by the hot water type heat exchanger 24 which is the main heating means.

In this way, the hot gas heater cycle H and the electric heater 3 are changed in accordance with the change in the evaporator outlet air temperature Te.
Even if the operation of 0 is controlled to be switched, the same effect as that of the first and second embodiments can be obtained.

(Fourth Embodiment) In the first to third embodiments, based on the outside air temperature Tam, the inside air temperature Tr, or the evaporator blown air temperature Te as the information indicating the heating heat load,
Although the operations of the hot gas heater cycle H and the electric heater 30 are switched and controlled, in the fourth embodiment, the hot gas heater cycle H and the hot gas heater cycle H are based on the engine water temperature Tw circulated in the hot water heat exchanger 24 forming the main heating means. Electric heater 3
The operation of 0 is switched and controlled.

That is, the hot gas heater cycle H and the electric heater 30 are the hot water heat exchanger 24 which constitutes the main heating means.
The heating capacity of the hot water heat exchanger 24 depends on the temperature of the engine cooling water (hot water) that is the heat source fluid, that is, the engine water temperature Tw. Therefore, the lower the engine water temperature Tw, the lower the heating capacity of the hot water heat exchanger 24, and it is necessary to increase the auxiliary heating capacity.

Based on such a relationship between the engine water temperature Tw and the auxiliary heating capacity, in the fourth embodiment, as shown in FIG. 6, in step S140, the engine water temperature Tw <the first predetermined value T1 (for example, 60). C.), it is determined that the heating capacity of the hot water heat exchanger 24 is small, and the hot gas heater cycle H and the electric heater 30 are simultaneously operated in step S130.

Then, the first predetermined value T1 ≦ engine water temperature T
When w <the second predetermined value T2 (for example, 80 ° C.),
It is determined that the heating capacity of the hot water heat exchanger 24 is in the intermediate state, the electric heater 30 is stopped in step S150, and the hot gas heater cycle H is operated independently.

When the engine water temperature Tw further rises and the engine water temperature Tw ≧ the second predetermined value T2 in step S160, it is determined that the heating capacity of the hot water heat exchanger 24 is sufficiently large, and step S170 is performed. In addition to stopping the electric heater 30, the hot gas heater cycle H is also stopped. Therefore, the air blown into the vehicle compartment is heated only by the hot water heat exchanger 24 which is the main heating means.

As described above, even if the hot gas heater cycle H and the operation of the electric heater 30 are switched and controlled in accordance with the change in the engine water temperature Tw, that is, the change in the heating capacity of the hot water heat exchanger 24, the same operation as in the first embodiment. Similar effects can be obtained.

In each of the above embodiments, steps S140 and S160 constitute the judging means of the present invention.

(Other Embodiments) The present invention is not limited to the above embodiments, but can be variously modified as follows.

(1) In each of the above embodiments, the necessity of operating the hot gas heater cycle H is determined in step S120 based on whether or not the hot gas switch 29b is turned on. However, the heating state of air conditioning is the maximum heating state. It may be determined that the hot gas heater cycle H needs to be operated if the maximum heating state is reached.

Specifically, the determination of the maximum heating state is performed by the cold air and hot water heat exchanger 24 bypassing the hot water heat exchanger 24.
If there is an air mix door (not shown) that controls the temperature of the air blown into the passenger compartment by adjusting the air flow rate of the hot air that passes through, the air mix door fully closes the cold air passage, The state in the maximum heating position where the air passage is fully opened can be determined as the maximum heating state. In addition, the hot water heat exchanger 24
When the circulating hot water flow rate is adjusted by the hot water valve 25 to control the temperature of the air blown into the vehicle compartment, the fully opened state of the hot water valve 25 can be determined as the maximum heating state.

(2) In each of the above-described embodiments, the electric heater 30 is simply turned on and off by fluctuations in the heating heat load, engine water temperature, etc., but the heat generation amount of the electric heater 30 is changed to the heating heat load and engine water temperature. You may make it switch to multiple steps according to the fluctuations of such as. That is, the heat generation amount of the electric heater 30 may be increased in multiple stages according to an increase in heating heat load or a decrease in engine water temperature.

(3) In the first to third embodiments, the outside air temperature T
The hot gas heater cycle H and the operation of the electric heater 30 are switched and controlled in accordance with the change of the heating heat load based on the am, the internal air temperature Tr, or the evaporator blown air temperature Te, and in the fourth embodiment, the engine water temperature is changed. Based on Tw,
The hot gas heater cycle H and the operation of the electric heater 30 are switched and controlled according to changes in the heating capacity of the hot water heat exchanger 24, but the heating heat load and the heating capacity of the hot water heat exchanger 24 are changed as necessary. In consideration of both changes, the operations of the hot gas heater cycle H and the electric heater 30 may be switched and controlled.

(4) For the above-mentioned reason, comparing the operation of the hot gas heater cycle H with the operation of the electric heater 30, the engine load becomes larger when the electric heater 30 is operated. The operation switching timing of the hot gas heater cycle H and the electric heater 30 may be determined in consideration of the change in the engine load in addition to the change in the heating heat load or the heating capacity of the hot water heat exchanger 24.

For example, the stop timing of the electric heater 30 and the hot gas heater cycle H, which is determined by the heating heat load or the heating capacity of the hot water heat exchanger 24, is corrected so as to be earlier when the engine load is large than when the engine load is small. May be.

(5) In the refrigerating cycle shown in FIG. 1, in the cooling mode, the liquid refrigerant separated into gas and liquid in the liquid receiver 15 is decompressed by the temperature type expansion valve 16, and the temperature type expansion valve 16 is used.
The cooling refrigeration cycle C for adjusting the superheat degree of the outlet refrigerant of the evaporator 18 is constituted by the above. However, by omitting the liquid receiver 15 and using a fixed throttle as the cooling decompression means, the accumulator 19 is provided. The cooling refrigeration cycle C may be configured by a so-called accumulator cycle in which the saturated gas refrigerant separated by gas and liquid is always sucked into the compressor 10.

[Brief description of drawings]

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

FIG. 2 is an electrical control block diagram of the first embodiment.

FIG. 3 is a flowchart illustrating the operation of the first embodiment.

FIG. 4 is a flowchart illustrating the operation of the second embodiment.

FIG. 5 is a flowchart illustrating the operation of the third embodiment.

FIG. 6 is a flowchart illustrating an operation of the fourth embodiment.

[Explanation of symbols]

10 ... Compressor, 18 ... Evaporator (indoor heat exchanger), 24 ...
Hot water heat exchanger, 30 ... Electric heater, H ... Hot gas heater cycle.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiaki Takano             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO (72) Inventor Masahiro Shoji             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd.

Claims (7)

[Claims] 1. A refrigeration cycle compressor (10) driven by a vehicle engine (12), comprising:
Hot gas heater cycle (H) that directly introduces the gas refrigerant discharged from (0) into the indoor heat exchanger (18) to heat the air blown into the vehicle compartment, and the electric heater (H) that heats the air blown into the vehicle compartment ( 30)
And a determining means for determining the heating heat load (S140, S160)
When the heating heat load determined by the determining means (S140, S160) is large, the hot gas heater cycle (H) and the electric heater (30) are both operated to reduce the heating heat load. Then, the electric heater (30)
Is first stopped to operate the hot gas heater cycle (H) independently, and then the hot gas heater cycle (H) is stopped when the heating heat load is further reduced. 2. The vehicle air conditioner according to claim 1, wherein the heating heat load is determined based on an outside air temperature. 3. The vehicle air conditioner according to claim 1, wherein the heating heat load is determined on the basis of the inside air temperature. 4. The indoor heat exchanger (1) is provided with the heating heat load.
The vehicle air conditioner according to claim 1, wherein the determination is made based on the blown air temperature of 8). 5. A hot water heating heat exchanger (24) for introducing hot water from the vehicle engine (12) to heat air blown into the vehicle compartment using the hot water as a heat source, the hot gas heater cycle ( H) and the electric heater (30) are the hot water heating heat exchanger (24).
The vehicle air conditioner according to any one of claims 1 to 4, which constitutes an auxiliary heating means for the. 6. A refrigeration cycle compressor (10) driven by a vehicle engine (12), said compressor (1)
Hot gas heater cycle (H) for directly introducing the discharge gas refrigerant from 0) into the indoor heat exchanger (18) to heat the air blown into the vehicle interior, and introducing hot water from the vehicle engine (12), A hot water heating heat exchanger (24) that heats air blown into the vehicle compartment using hot water as a heat source, and an electric heater (30) that heats air blown into the vehicle compartment.
And a determination unit (S140, S160) for determining the heating capacity of the heating heat exchanger (24), and when the heating capacity determined by the determination unit (S140, S160) is small, the hot When the gas heater cycle (H) and the electric heater (30) are operated together and the heating capacity increases, the electric heater (30) is stopped first and the hot gas heater cycle (H) is operated independently, and then When the heating capacity further increases,
A vehicle air conditioner characterized by stopping the hot gas heater cycle (H). 7. The vehicle air conditioner according to claim 6, wherein the heating capacity is determined based on the temperature of the hot water.