JP4096548B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner, and is particularly effective when applied to an air conditioner including a hybrid drive type compressor.
[0002]
[Prior art and problems to be solved by the invention]
As described in Utility Model Registration Publication No. 2596291, the hybrid drive type compressor switches a traveling engine and an electric motor to drive the compressor.
[0003]
By the way, this hybrid drive type compressor is generally applied to a vehicle air-conditioning system that improves vehicle fuel efficiency and reduces exhaust gas. At times, the compressor is driven by the engine, and when the vehicle stops, such as when waiting for traffic lights or traffic jams, the engine is stopped to improve vehicle fuel efficiency and reduce exhaust gas, while driving the compressor with an electric motor. Maintain air conditioning capacity.
[0004]
However, when the compressor is driven by the electric motor, the engine is stopped and the generator is stopped. Therefore, the electric motor must be driven only by the electric power stored in the battery. The amount of power saved will drop.
[0005]
Therefore, the inventors circulate the refrigerant in the refrigerator when driving the compressor with the electric motor, compared with the case where the compressor is driven with the engine, in order to reduce power consumption in the electric motor. A prototype of an air conditioner that reduces the power consumption of the compressor, that is, the power consumption of the electric motor, by reducing the flow rate has been studied, but the following problems have newly occurred.
[0006]
That is, the driving torque of the compressor increases as the discharge pressure (high-pressure side refrigerant pressure) of the compressor increases. As described above, when the compressor is driven by the engine, the compressor is driven by the electric motor. Since the refrigerant flow rate is increased and a large refrigerating capacity is exhibited as compared with the case where the refrigerant is discharged, the discharge pressure of the compressor is relatively high.
[0007]
In addition to the fact that the opening of the thermal expansion valve, which is a decompression device, does not change immediately after the compressor stops, the valve body of the expansion valve opens the valve opening when the compressor stops. Since it moves in the closing direction, the high-pressure side refrigerant pressure is in a state where a relatively high pressure is maintained when the engine is driven.
[0008]
Therefore, if the compressor is driven by the electric motor after the engine is stopped and the high-pressure side refrigerant pressure is high, a large driving torque is required by the electric motor, so that the power consumption and the size of the electric motor are increased. I will invite you.
[0009]
In view of the above points, the present invention reduces and reduces the power consumption of a driving source different from the engine in an air conditioner that drives a compressor by switching between a driving engine and a driving source different from the engine such as an electric motor. It aims to plan.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in the invention described in claim 1, power is obtained from the driving source (200) for traveling and the second driving source (210) different from the driving source (200). The compressor (100) that sucks and compresses the refrigerant, the radiator (110) that cools the refrigerant discharged from the compressor (100), and the radiator (110) that is in continuous communication at least when the air conditioner is in operation. e Bei decompressor for decompressing the leaked refrigerant (120), decompressor evaporator for evaporating the refrigerant reduced in pressure by (120) and (130),
The second drive source (210) is an electric motor,
Furthermore, the second drive source (210) is characterized in that it starts to operate when the refrigerant pressure before and after the pressure reducing device (120) becomes substantially equal .
[0011]
As a result, when the drive source (200) is stopped, the refrigerant on the radiator (110) side moves to the evaporator (130) side via the decompression device (120), the high-pressure side refrigerant pressure decreases, and the decompression device ( 120) Since the refrigerator equalizes pressure so that the refrigerant pressure before and after becomes substantially equal, the driving torque when the compressor (100) is driven by the second driving source (210) can be reduced. Therefore, it is possible to reduce the size of the electric motor forming the second driving source (210) while reducing the power consumption of the electric motor forming the second driving source (210).
[0012]
The decompression device (120) may be constituted by a capillary tube or a fixed throttle as in the invention described in claim 2.
[0013]
Further, as in the third aspect of the present invention, the temperature type expansion valve (121) for mechanically adjusting the valve opening degree so that the refrigerant superheat degree on the outlet side of the evaporator (130) becomes a predetermined value, and the temperature type expansion The decompression device (120) may be configured by a throttle means (122) that causes the refrigerant to flow around the valve (121).
[0020]
According to a fourth aspect of the present invention, in the vehicle air conditioner according to any one of the first to third aspects, the compressor (100) is a variable capacity compressor capable of changing a discharge capacity. In addition, when the compressor (100) is driven by the second drive source (210), the discharge capacity of the compressor (100) is set to a discharge capacity smaller than the maximum discharge capacity.
[0021]
Thereby, since the torque at the time of driving the compressor (100) can be further reduced, the power consumption of the electric motor constituting the second drive source (210) can be further reduced.
[0022]
Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 is a schematic view of a vehicle air conditioner (vapor compression refrigerator) according to the present embodiment. The compressor 100 sucks and compresses a refrigerant. The compressor 100 includes a traveling engine 200 and an electric motor. A driving force is obtained from the motor 210 of the formula.
[0024]
The motor 210 is integrated with a pulley 230 on which a V-belt 220 that transmits the power of the engine 200 to the compressor 100 is applied.
[0025]
The radiator (condenser) 110 heats the refrigerant discharged from the compressor 100 and the outside air to cool the refrigerant, and the decompression device 120 decompresses and expands the refrigerant flowing out of the radiator 110.
[0026]
The evaporator 130 heat-exchanges the low-pressure refrigerant decompressed by the decompression device 120 and the air blown into the room to evaporate the liquid-phase refrigerant. The accumulator 140 converts the refrigerant flowing out of the evaporator 130 into the liquid-phase refrigerant. Gas-liquid separation means that separates the gas-phase refrigerant and stores the liquid-phase refrigerant, and causes the gas-phase refrigerant to flow out to the suction side of the compressor 100.
[0027]
Here, the decompression device 120 is a narrow capillary tube that generates a predetermined pressure loss in accordance with the flow rate of the refrigerant in a state where the refrigerant passage is always in communication, like a fixed throttle (orifice) having a fixed opening.
[0028]
Next, the characteristic operation of this embodiment will be described.
[0029]
FIG. 2 is a chart showing changes in the flow rate of the refrigerant circulating in the refrigerator. When the vehicle is running, the compressor 100 is driven by the engine 200, and when the vehicle is stopped such as waiting for a signal or traffic jam, When the time ΔT has elapsed, the motor 210 is operated to drive the compressor 100, and the average refrigerant flow rate Va circulating in the refrigerator regardless of the air conditioning load in the evaporator 130 causes the engine 200 to cause the compressor 100 to operate. The flow rate of the refrigerant discharged from the compressor 100 is periodically changed so as to be smaller than the refrigerant flow rate when driving.
[0030]
Here, the average refrigerant flow rate Va when driving the compressor 100 with the motor 210 is a refrigerant flow rate that does not greatly deteriorate the air conditioning feeling, and the maximum refrigerant flow rate when the compressor 100 is driven with the motor 210. Vmax is equivalent to the lower limit value of the refrigerant flow rate in which no significant deviation occurs in the refrigerant flow in the evaporator 130.
[0031]
Next, the function and effect of this embodiment will be described.
[0032]
According to this embodiment, since the decompression device 120 is constituted by a capillary tube, the front and rear of the decompression device 120 are always in communication. For this reason, when the engine 200 is stopped, the high-pressure side refrigerant moves to the low-pressure side via the decompression device 120, the high-pressure side refrigerant pressure decreases, and the refrigerator is arranged so that the refrigerant pressure before and after the decompression device 120 becomes substantially equal. Since the pressure is equalized, the driving torque when the compressor 210 is driven by the motor 210 can be reduced. Therefore, it is possible to reduce the size of the motor 210 while reducing the power consumption of the motor 210.
[0033]
Further, in the present embodiment, when the vehicle is stopped such as waiting for a signal or traffic jam, the motor 210 is operated when the predetermined time ΔT has elapsed after the engine 200 is stopped, so that the power consumption of the motor 210 can be further reduced. Can do.
[0034]
Note that the predetermined time ΔT is a time required for the refrigerant pressures before and after the decompression device 120 to become substantially equal after the engine 200 is stopped. In the present embodiment, a predetermined time (for example, 20 seconds) ) As a predetermined time ΔT.
[0035]
By the way, when the refrigerant flow rate decreases, the refrigerant flowing in the evaporator 130 flows in the evaporator 130 so as to gather in a passage having a small pressure loss among the many refrigerant passages from the refrigerant inlet to the refrigerant outlet. There is a high risk that air flow feeling will deteriorate because the temperature of the cold air that has passed through the evaporator 130 is different in the portion of the evaporator 130 that passes through, due to a significant bias in the refrigerant flow.
[0036]
On the other hand, in this embodiment, since the flow rate of the refrigerant discharged from the compressor 100 is periodically changed, it is possible to prevent a significant deviation in the refrigerant flow in the evaporator 130.
[0037]
Therefore, the power consumption (power consumption) in the motor 210 can be reduced by lowering the average refrigerant flow rate Va while preventing the deterioration of the air conditioning feeling due to the bias of the refrigerant flow generated in the evaporator 130. .
[0038]
By the way, after the compressor 100 is stopped, the temperature of the evaporator 130 or the air temperature immediately after passing through the evaporator 130 increases according to the refrigerant remaining in the evaporator 130 and the heat capacity of the evaporator 130. Since the device 120 is constituted by a capillary tube, the liquid phase refrigerant on the high pressure (heat radiator 110) side can be supplied to the evaporator 130 due to the difference between the high and low pressures remaining. As a result of evaporation, the temperature rise of the evaporator 130 can be suppressed.
[0039]
Therefore, it is possible to prevent the air conditioning feeling (cool feeling) from being greatly impaired even if the motor 210 is not operated at the same time as the engine 200 is stopped. Therefore, the operation time of the motor 210 can be shortened, and the power consumption of the motor 210 is reduced. Can be further reduced.
[0040]
(Second Embodiment)
In the first embodiment, the decompression device 120 is configured by a capillary tube. However, in this embodiment, as shown in FIG. 3, the valve opening degree is set so that the refrigerant superheat degree on the outlet side of the evaporator 130 becomes a predetermined value. The pressure-reducing device 120 includes a temperature-controlled expansion valve 121 that is mechanically adjusted, and a capillary tube that bypasses the temperature-type expansion valve 121 and flows a refrigerant, and a throttle 122 such as a fixed throttle.
[0041]
Incidentally, as shown in FIG. 4, the temperature type expansion valve 121 causes the saturation pressure due to the refrigerant temperature on the refrigerant outlet side of the evaporator 130 to act on the upper surface side of the diaphragm 121a, while the lower surface side of the diaphragm 121a By applying the refrigerant pressure on the refrigerant outlet side of the evaporator 130 and the elastic force by the spring 121b, the valve element 121c is displaced according to the pressure difference applied by the diaphragm 121a, and the valve opening degree is adjusted.
[0042]
In the present embodiment, the pressure sensor 123 detects the high-pressure side refrigerant pressure, and after the engine 200 is stopped when the air conditioner is in operation (the A / C switch is turned on), the pressure sensor 123 When the detected pressure becomes equal to or lower than a predetermined pressure, the motor 210 is operated assuming that the refrigerator is equalized.
[0043]
Next, the function and effect of this embodiment will be described.
[0044]
When the engine 200 is stopped and the compressor 100 is stopped, the temperature type expansion valve 121 moves in the direction in which the valve closes due to its structure (see FIG. 4), and the engine 200 drives the compressor 100. Since the refrigerant flow rate at that time is larger than the refrigerant flow rate at which the motor 210 drives the compressor 110, the refrigerant pressure on the high-pressure side is relatively high immediately after the engine 200 is stopped.
[0045]
On the other hand, in the present embodiment, even if the temperature type expansion valve 121 is closed, the high-pressure side refrigerant moves to the low-pressure side via the throttle 122 and the high-pressure side refrigerant pressure decreases, and the refrigerant pressure before and after the decompression device 120 (The refrigerator equalizes the pressure so that the driving torque when the compressor 100 is driven by the motor 210 can be reduced. Therefore, the motor 210 consumes less power and reduces the motor power consumption. The size of 210 can be reduced.
[0046]
Needless to say, in the present embodiment, the throttle 122 may be provided in the temperature type expansion valve 121.
[0047]
(Other embodiments)
In the above-described embodiment, the predetermined time ΔT is a fixed time obtained in advance by a test. However, the present invention is not limited to this, and when the refrigerator is equalized, the predetermined time ΔT Since the temperature and pressure rise, the motor 210 may be started when the temperature of the evaporator 130 becomes a predetermined temperature or higher after the engine 200 is stopped. Further, the predetermined time ΔT may be changed based on parameters related to the air conditioning load such as the inside air temperature, the outside air temperature, and the amount of solar radiation.
[0048]
In the above-described embodiment, the compressor 110 is of a fixed capacity type. However, when the compressor 100 is a known variable capacity compressor and the motor 210 is driven by the motor 210, the compressor 110 is a fixed capacity type. The discharge capacity of the compressor 100 may be smaller than the maximum discharge capacity. In this way, since the torque when driving the compressor 100 can be reduced, the power consumption of the motor 210 can be further reduced, and the motor 210 can be reduced in size.
[0049]
Further, in the above-described embodiment, the refrigerant flow rate is changed in a rectangular wave shape, but the present invention is not limited to this, and may be, for example, a triangular wave shape, a sawtooth wave shape, or a sine wave shape.
[0050]
In the above-described embodiment, the maximum flow rate Vmax and the period when the motor is driven are constant, but the present invention is not limited to this, and the maximum flow rate Vmax and the period may be changed.
[0051]
In the above-described embodiment, the present invention can be implemented even if a fixed throttle such as an orifice is employed instead of the capillary tube.
[0052]
Further, the decompression device 120 may be an electric expansion valve, and at least when the air conditioner is in operation, the refrigerant flowing out of the radiator 110 may be decompressed in a constantly connected state.
[0053]
In the above-described embodiment, the refrigerant flow rate is changed when the motor is driven. However, the present invention is not limited to this, and the refrigerant flow rate when the motor is driven may be substantially constant.
[0054]
Further, an electromagnetic valve is provided on the upstream side of the refrigerant flow in the capillary tube 120, and the time ΔT ′ (for example, shorter than a predetermined time ΔT from when the traveling engine is stopped until before the motor 210 is started, that is, when the engine is stopped). 10 to 15 seconds), the solenoid valve may be closed to prevent the high temperature / high pressure refrigerant from flowing into the evaporator 130.
[0055]
Further, when the vehicle is stopped such as waiting for a signal or traffic jam, it is desirable to implement the above-described control as the inside air circulation mode in order to reduce the air conditioning load.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an air conditioner according to a first embodiment of the present invention.
FIG. 2 is a chart showing the relationship between the refrigerant flow rate and time in the air conditioner according to the first embodiment of the present invention.
FIG. 3 is a schematic diagram of an air conditioner according to a second embodiment of the present invention.
FIG. 4 is a schematic diagram of an expansion valve applied to an air conditioner according to a second embodiment of the present invention.
[Explanation of symbols]
100 ... Compressor, 110 ... Heat radiator,
120 ... capillary tube (decompression device), 130 ... evaporator,
140 ... accumulator, 200 ... engine (drive source),
210: Motor (second drive source).

Claims (4)

A driving source (200) for traveling, and a compressor (100) that obtains power from a second driving source (210) different from the driving source (200) and sucks and compresses the refrigerant;
A radiator (110) for cooling the refrigerant discharged from the compressor (100);
At least during operation of the air conditioner, a decompression device (120) that decompresses the refrigerant that has flowed out of the radiator (110) in a constantly communicating state;
Bei example an evaporator and (130) for evaporating the decompressed refrigerant by the pressure reducing device (120),
The second drive source (210) is an electric motor,
Further, the vehicle air conditioner is characterized in that the second drive source (210) starts to operate when the refrigerant pressure before and after the pressure reducing device (120) becomes substantially equal .   The vehicle air conditioner according to claim 1, wherein the pressure reducing device (120) is configured by a capillary tube or a fixed throttle.   The pressure reducing device (120) includes a temperature type expansion valve (121) that mechanically adjusts the valve opening degree so that the degree of refrigerant superheating on the outlet side of the evaporator (130) becomes a predetermined value, and the temperature type expansion valve ( 121. The vehicle air conditioner according to claim 1, wherein the vehicle air conditioner includes a throttle means (122) that causes the refrigerant to flow while bypassing 121). The compressor (100) is a variable capacity compressor capable of changing a discharge capacity,
Further, when the compressor (100) is driven by the second drive source (210), the discharge capacity of the compressor (100) is set to a discharge capacity smaller than the maximum discharge capacity. The vehicle air conditioner according to any one of claims 1 to 3 .

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