JPH10119561A - Air conditioner for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner for an automobile allowing quick heating by increasing the quantity of the refrigerant circulating in a circuit even when the heating operation is started. SOLUTION: The first heat exchanger 1b functioning as an evaporator is provided with an expansion valve by-pass means 15 circulating a refrigerant around an expansion valve EXb provided on an inlet pipe Pa on the inflow side of the refrigerant. In the heating operation when the outside air temperature is low, the refrigerant is circulated around the expansion valve EXb by the expansion valve by-pass means 15, the refrigerant in a circuit is fed back to a compressor 6 without being obstructed by the expansion valve EXb, it is discharged as the high-temperature and high-pressure refrigerant after being compressed by the compressor 6, and the quick heating property is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automotive air conditioner capable of rapid heating.

[0002]

2. Description of the Related Art In a conventional heating operation by an air conditioner for a vehicle, engine cooling water is used as a heat source, and a part of the engine cooling water is led to a heater core in a vehicle compartment, where heat exchange is performed with the vehicle interior air. Generally, a hot water type is used in which heated air is blown into a vehicle interior.

There is also known a heat pump type air conditioner which draws heat from outside air without using engine cooling water as a heat source for heating and uses the heat for heating a vehicle interior.

Further, in a so-called dual air conditioner in which air conditioning units are separately arranged for a front seat and a rear seat in a vehicle compartment, both are of a type using hot water, both are of a heat pump type, or one is of a type using hot water. And the other is a heat pump type.

[0005]

However, in a heat pump type air conditioner, the heat source for heating is mainly energy supplied during the compression work of the compressor, and the heating performance is determined by the amount of circulating refrigerant. And the enthalpy difference resulting from the compression work of the compressor, the high heating performance cannot be obtained when the outside air temperature is low and the flow rate of the refrigerant is small.

For example, when the outside air temperature is low and the temperature in the vehicle compartment is low, such as when the operation is started early in the winter, the system components are cold.
It is extremely small and hardly allows a refrigerant to pass through.
If the heating operation is performed in this state, the circulation of the refrigerant in the circuit is hindered, the amount of the refrigerant returning to the compressor is reduced, and even if the heating operation is performed rapidly, the temperature rise in the vehicle interior becomes extremely slow.

[0007] Further, since the outdoor heat exchanger is cooled by low-temperature outside air, the evaporation capacity is extremely reduced, and the refrigerant in the lubricating oil stored in the compressor causes so-called forming, and the compressor slides. The moving part is not sufficiently lubricated, and a heavy load is applied to the sliding part. Therefore,
The flow rate of the refrigerant discharged from the compressor decreases, and the desired heating operation cannot be performed.

[0008] The same applies to a hot water type air conditioner. When the outside air temperature is low and the temperature in the vehicle compartment is low, such as when the operation is started in the early morning of winter, the heating capacity at the time of starting the engine is extremely low. Until the temperature of the engine rises considerably, it is difficult to obtain hot air at a desired temperature.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an air conditioner for a vehicle which has a large amount of circulating refrigerant even at the start of a heating operation and is capable of rapid heating. And

[0010]

According to a first aspect of the present invention, there is provided a compressor, a first heat exchanger, an expansion valve, and a second heat exchanger which constitute a closed circuit by piping. In the air conditioner for automobiles, which is provided with the expansion valve in an inlet pipe on the side where the refrigerant flows into the first heat exchanger, the refrigerant bypasses the expansion valve when heating operation is started. An air conditioner for an automobile, characterized in that an expansion valve bypass means for flowing down the air is provided.

[0011] In the air conditioner for a vehicle configured as described above, as in the case where the heating operation is started in winter,
Even when the expansion valve is throttled because the outside air temperature is low, the refrigerant is returned to the compressor by the expansion valve bypass means, bypassing the expansion valve, and a large amount of high-temperature and high-pressure refrigerant compressed by the compressor is supplied. If the air is circulated in the closed circuit, the temperature in the passenger compartment rapidly rises immediately after the start of operation, and rapid heating can be performed.

The expansion valve bypass means includes a bypass pipe for the expansion valve, and a switching member for switching a flow direction of the refrigerant to each of the bypass pipe and the inlet pipe.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an air conditioner for a vehicle according to an embodiment of the present invention, and FIG. 2 is an enlarged explanatory diagram showing a main part of FIG.

The present embodiment is a dual type air conditioner for a vehicle in which two independent air conditioners are provided in parallel. As shown in FIG. 1, this air conditioner is selected from an intake unit (not shown). It has a front seat unit Ua for air-conditioning the inside and outside air taken in and blowing it to the front seat, and a rear seat unit Ub for air-conditioning and blowing the inside air taken in to the rear seat.

In the front seat unit Ua, an intake unit (not shown), an intake door, a blower, an evaporator 1a as a first heat exchanger, an air mixing door 2a, and a heater core 3a are arranged in this order from the upstream side in the air passage. In addition, an outlet (not shown) is provided to a vehicle interior, and the first hot water line and the first refrigerant line are connected.

On the other hand, the rear seat unit Ub has a blower (not shown), an evaporator 1b as a first heat exchanger, an air mixing door 2b, and a condenser as a second heat exchanger, in that order from the upstream side in the air passage. 4b is arranged, and the second refrigerant line is connected.

The first hot water line is constructed by sequentially connecting the engine 5, the water valve Wv, and the heater core 3a by piping.

The first refrigerant line includes a compressor 6, a three-way connector 7, an electromagnetic valve 8a as a switching member for switching the flow direction of the refrigerant, a condenser 4a as a second heat exchanger, a check valve 9, and a three-way connector 10. , Liquid tank L, three-way connector 11, solenoid valve 8b, expansion valve EXa, evaporator 1
a and the three-way connector 12 are sequentially connected by a pipe P.

The piping P between the three-way connectors 7 and 10
Is a bypass pipe section for the condenser 4a,
Together with the solenoid valve 8c, it constitutes a capacitor bypass means.

The second refrigerant line connects a three-way connector 11, a solenoid valve 8d, which is a switching member for switching the flow direction of the refrigerant, a condenser 4b, an expansion valve EXb, an evaporator 1b, and a three-way connector 12 in order by a pipe P. It is configured. That is, the three-way connectors 11 and 12 branch in parallel from the first refrigerant line of the front seat unit Ua. Note that reference numeral “13” in the drawing is a fan that promotes heat exchange between the outside air and the refrigerant in the condenser 4a.

In particular, in the present embodiment, as shown in FIG. 2, the refrigerant flows down the expansion valve EXb provided in the inlet pipe Pa through which the refrigerant flows into the evaporator 1b as the first heat exchanger. There is provided an expansion valve bypass means 15 for performing the operation. The expansion valve bypass means 15 includes an expansion valve EXb.
And solenoid valves 17a and 17b which are switching members for switching the flow direction of the refrigerant to the bypass pipe 16 and the inlet pipe Pa. Although the flow rate of the refrigerant flowing around the expansion valve EXb can be adjusted by appropriately selecting the diameter of the pipe, a fixed orifice 18 may be provided in the middle of the bypass pipe 16 to adjust the flow rate of the refrigerant as shown in the figure. . In this case, the expansion valve EXb
Needless to say, it is necessary to select the fixed orifice 18 having a passage resistance smaller than the passage resistance of the fixed orifice 18.

It should be noted that the expansion valve bypass means 15 is not limited to the configuration of the illustrated example. For example, a three-way valve may be used instead of the solenoid valve 17 (a generic name of 17a and 17b) as a switching member.

The expansion valve bypass means 15 may be provided not only on the expansion valve EXb of the rear seat unit Ub but also on the expansion valve EXa of the front seat unit Ua.

The expansion valve EX (general term for EXa and EXb)
For example, as shown in FIG. 3, an inlet port 21 and an outlet port 22 are formed in the main body 20, and these two ports 2
A throat portion 23a and an expansion chamber 23b are provided in the middle of a communication passage connecting the first and second tubes 22. The throat 23a is opened and closed by a ball valve 24 to control the flow rate of the refrigerant and adiabatically expand the refrigerant.

The ball valve 24 is fixed to a valve holder 25 in the expansion chamber 23b.
A spring 27 is mounted between the adjusting screw 26 screwed into the outlet port 22.

The housing 3 provided on the upper part of the main body 20
In the pressure equalizing chamber 33, there is provided a diaphragm 31 for separating a pressurizing chamber 32 and a pressure equalizing chamber 33.
5, the pressure of the refrigerant at the outlets of the evaporators 1b, 1a acts. A stopper 35 is provided in the pressure equalizing chamber 33 so as to contact the lower surface of the diaphragm 31. Both ends of the operating rod 38 contact the stopper 35 and the valve holder 25. The diaphragm 31 is connected to the ball valve 24 in conjunction with the operation of the diaphragm 31.
Is activated.

At the outlet of the evaporator 1b, a temperature sensing tube K2 is provided.
The temperature-sensitive cylinder K2 is communicated with the inside of the housing 30 by a capillary tube 41, and a working fluid as an inert gas such as a refrigerant sealed in the temperature-sensitive cylinder K2 is introduced into the pressurizing chamber 32. It is supposed to be.

Therefore, for example, when a working fluid of the same type as the refrigerant in the closed circuit constituting the cooling cycle is sealed in the temperature-sensitive cylinder K2, the working fluid is supplied to the evaporator 1
The temperature corresponds to the temperature of the outlets b and 1a, and a pressure corresponding to the temperature is applied to the inside of the pressurizing chamber 32. Then, the pressure in the pressurizing chamber 32 and the pressure in the equalizing chamber 33, that is, the refrigerant pressure immediately after the evaporator 1b and the spring 2
The ball valve 24 opens and closes the throat portion 23a at an opening that balances the resilience of the throat 23. Thereby, the refrigerant having the predetermined degree of superheat is returned to the compressor.

Here, when heating the vehicle by starting the vehicle engine and operating the compressor 6 in a state where the outside air temperature is low, the temperature sensing tube K2 senses a cold outside air temperature, The pressure of the working fluid in the temperature sensing cylinder K2 does not increase, and the expansion valve EXb is in a state in which the valve opening is narrowed. Therefore, the amount of the refrigerant circulating in the circuit by the expansion valve EXb is extremely small, and the amount of the refrigerant that is inevitably returned to the compressor 6 is also small, so that it is impossible to discharge a large amount of the refrigerant for heating.

However, in the present embodiment, while the solenoid valve 17a provided in the bypass pipe 16 is opened and the solenoid valve 17b provided in the inlet pipe Pa is closed, a large amount of gas is bypassed to the compressor 6 by bypassing the expansion valve EXb. The refrigerant is fed back so that a large amount of the refrigerant circulates through the closed circuit.

Next, the operation when the heating operation is performed will be described. In the heating operation in the present embodiment, the heat source differs between the front seat unit Ua and the rear seat unit Ub, and the front seat unit Ua supplies the engine cooling water with the rear seat unit Ub.
Uses a refrigerant.

Therefore, when performing the heating operation,
Solenoid valves 8a, which are switching members for switching the flow direction of the refrigerant,
8b is in a "closed state", the solenoid valves 8c and 8d are in an "open state", and the refrigerant from the compressor 6 receives the refrigerant from the three-way connector 7 → the solenoid valve 8c → the three-way connector 10 → the liquid tank L → the three-way connector 11 → the solenoid. Valve 8d → condenser 4b → solenoid valve 17b of inlet piping Pa → expansion valve EXb → evaporator 1b
→ Flow with the three-way connector 12. Further, the water valve Wv is also kept in the “open state”.

When the heating operation is performed in such a state that the outside air temperature is low and the temperature in the vehicle compartment is low, such as in the early morning of winter, the working fluid sealed in the temperature-sensitive cylinder K2 is reduced. The pressure corresponding to the temperature exerted is weak, and the expansion valve E
Xb is in a state in which the ball valve 24 closes the throat portion 23a by the force of the spring 27, or is heat-exchanged by the evaporator 1b, and is sufficiently throttled so as not to send the liquid refrigerant to the compressor 6. .

In this state, even if the automobile engine is started and the compressor 6 is operated, the flow of the refrigerant is blocked by the expansion valve EXb, the amount of the refrigerant returning to the compressor 6 becomes extremely small, and rapid heating cannot be performed.

Therefore, in the present embodiment, while the solenoid valve 17a provided on the bypass pipe 16 is opened, the solenoid valve 17b provided on the inlet pipe Pa is closed, and the refrigerant in the circuit flows through the expansion valve EX.
b to make it easier to return to the compressor 6.

In this state, a large amount of refrigerant in the circuit is sucked into the compressor 6 by the operation of the compressor 6 and is compressed and discharged in a large amount. In addition, an accumulator may be provided between the three-way connector 12 and the compressor 6 so that the refrigerant that cannot be vaporized by the evaporator 1b is separated into a gas and a liquid so that the gas refrigerant is returned to the compressor 6 for protection.

The refrigerant discharged from the compressor 6 is supplied to the three-way connector 7 → the solenoid valve 8c → the three-way connector 10 → the liquid tank L → the three-way connector 11 → the solenoid valve 8d → the condenser 4
b → electromagnetic valve 17a of bypass pipe 16 → evaporator 1
b → flows through the three-way connector 12 and returns to the compressor 6.

Note that the refrigerant that has entered the liquid tank L also flows while pushing out the refrigerant stored in the liquid tank L.

Therefore, since the expansion valve EXb does not hinder the flow of the refrigerant from the beginning of the heating operation, the amount of the refrigerant circulating in the circuit is sufficiently secured, and the condenser 4b exchanges heat between the vehicle interior air and the high-temperature and high-pressure refrigerant. Is performed, and the heated vehicle interior air is sent into the vehicle interior by the blower, thereby rapidly heating the vehicle interior.

That is, since a large amount of high-temperature and high-pressure refrigerant pressurized by the compressor 6 is used to heat the vehicle interior, the temperature of the vehicle interior air rises very quickly, and the instantaneous warming is improved. Become.

When the temperature in the passenger compartment rises to some extent by such a rapid heating operation, the operation is switched to the normal operation.
That is, the discharge pressure (the temperature of the discharged refrigerant in the case of the temperature switch) of the compressor 6 is detected by the pressure switch PS (which may be a temperature switch) shown in FIG. ), The solenoid valve 17a provided in the bypass pipe 16 is closed, while the solenoid valve 17b provided in the inlet pipe Pa is opened. After this, the expansion valve E
Xb operates to have an opening corresponding to the temperature at the outlet pipe of the evaporator 1b. The operation of switching from the rapid heating operation to the normal operation may be performed by timer control. During normal operation in rear seat heating, air blown into the vehicle compartment is heated by the condenser 4b while being dehumidified by the evaporator 1b.

In this embodiment, the heating for the front seat is
The cooling operation is performed after the temperature of the engine cooling water rises. However, as described above, the heating is started in the rear seat unit Ub. Front seat occupants are also rear seat units Ub
You can take advantage of the benefits of improved immediate warmth and surpass the cold.

When the temperature of the engine coolant rises, the engine coolant with a large amount of heat is guided to the heater core 3a, and air at a desired temperature is also blown out to the front seat.

In the embodiment described above, the rear seat unit Ub
Only the heating operation with good immediate heating is performed, but the present invention is not limited to this. The expansion valve EXa of the front seat unit Ua is also provided with an expansion valve bypass means to open the solenoid valve provided in the bypass pipe and close the solenoid valve provided in the inlet pipe, thereby closing the front seat unit Ua.
The high-temperature and high-pressure refrigerant is also supplied to the evaporator 1a of the rear seat unit Ub and the evaporator 1b of the rear seat unit Ub.
b around the front seat unit Ua and the rear seat unit U
b may be heated at the same time.

The present invention can also be applied to a heat pump type air conditioner which draws heat from outside air and uses it for heating the interior of a vehicle as shown in FIG. What is shown here is different from the one shown in FIG.
This is a heat pump air conditioner that does not have a dehumidifying function during a heating operation.

The configuration of the heat pump type air conditioner shown in FIG. 4 includes a compressor 6 and a switching member V (this embodiment) for switching the flow direction of the refrigerant (broken arrow for cooling, solid arrow for heating). Uses a four-way valve),
A second heat exchanger 4 for exchanging heat between the indoor air and the refrigerant to cool or heat the indoor air (functions as an evaporator during cooling and functions as a condenser during heating), indoor expansion valve EXi, liquid tank L, outdoor Expansion valve EX
o, having a first heat exchanger 1 (functions as a condenser during cooling and functions as an evaporator during heating),
These are connected via a pipe P, a three-way connector and a check valve C so as to form a closed circuit.

An expansion valve bypass means 15 is provided to bypass the outdoor expansion valve EXo provided in the inlet pipe Pa through which the refrigerant flows into the first heat exchanger 1 functioning as an evaporator at the time of heating and to flow the refrigerant. ing.

In this case, too, the bypass piping 16
When the electromagnetic valve 17a provided in the inlet pipe Pa is opened and the electromagnetic valve 17b provided in the inlet pipe Pa is closed to make it easier for the refrigerant in the circuit to return to the compressor 6, the immediate warming can be improved.

[0049]

As described above, according to the present invention, when the heating operation is started, a large amount of refrigerant is returned to the compressor by bypassing the expansion valve by the expansion valve bypass means to heat the vehicle interior. Thus, it is possible to rapidly heat immediately after the start of operation. Also, the so-called forming caused by the refrigerant in the lubricating oil, which occurs when the outside air temperature is low, can be prevented, sufficient lubrication can be achieved, and a large load is not applied to the sliding portion of the compressor. Oil shortage can also be prevented, and high-speed rotation of the compressor becomes possible, which can also improve immediate warming due to an increase in refrigerant flow rate.

[Brief description of the drawings]

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

FIG. 2 is an enlarged explanatory view showing a main part of FIG.

FIG. 3 is a sectional view of an expansion valve.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1, 1a, 1b: first heat exchanger 4a: second heat exchanger 6: compressor 15: expansion valve bypass means 16: bypass pipe 17a, 17b: solenoid valve (switching member) EX: expansion valve P: pipe Pa: Inlet piping

Claims (2)

[Claims] 1. A compressor (6), a first heat exchanger (1)
a, 1b), the expansion valve (EX) and the second heat exchanger (4
a) is connected by a pipe (P) to form a closed circuit, and the expansion valve (EX) is connected to an inlet pipe (Pa) on the side where the refrigerant flows into the first heat exchanger (1a, 1b). An air conditioner for a vehicle, comprising: expansion valve bypass means (15) for bypassing the expansion valve (EX) and flowing refrigerant when starting a heating operation. apparatus. 2. The expansion valve bypass means (15) includes a bypass pipe (16) for the expansion valve (EX), and a flow direction of a refrigerant to each of the bypass pipe (16) and the inlet pipe (Pa). (1)
7. The air conditioner for a vehicle according to claim 1, comprising: