JP3830239B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner for a vehicle that prevents a differential pressure between a discharge side and a suction side of a compressor from becoming excessive and allows a compressor to be restarted smoothly.
[0002]
[Prior art]
As a conventional vehicle air conditioner, for example, a device as shown in FIG. 3 is known.
The illustrated vehicle air conditioner 200 includes a compressor 20, a condenser 30, a sub condenser 40 that functions as a heater, a liquid receiver 50, an expansion valve 210, and an evaporator 70 connected by a refrigerant pipe 80 so as to form a closed circuit. A refrigeration cycle is configured, and a sub capacitor 40 and an evaporator 70 which are components of the refrigeration cycle are installed in a unit case 90 provided in a vehicle interior.
[0003]
In FIG. 3, “21” indicates an accumulator that prevents the reverse flow of the refrigerant from the compressor 20, “31” indicates a fan that blows air to the capacitor 30, and “i” indicates an inverter.
[0004]
The unit case 90 is configured by arranging an intake unit 130, a cooler unit 140, and a heater unit 160 in series, and the intake unit 130 is disposed upstream from the air flow direction (indicated by a white arrow). It consists of an intake door 100 for selectively introducing outside air and inside air, a filter 110 and an indoor blower 120. The cooler unit 140 is provided with an evaporator 70 in the air passage 91. A mix door 150 is provided for adjusting the mixing ratio of the warm air heated by the sub-capacitor 40 provided in the air passage 91 and the cold air flowing bypassing the sub-capacitor 40.
[0005]
By the way, in such a vehicle air conditioner 200, when the compressor 20 is temporarily stopped and then restarted, if the refrigerant pressure difference between the discharge side and the suction side of the compressor 20 is large, an excessive compression force is generated. It may occur and the compressor 20 may be locked. Once the compressor 20 is stopped, it cannot be restarted until the pressure difference between the discharge side and the suction side of the compressor 20 becomes small, and it takes a long time to reach the restartable pressure difference. Since it will stop, there is a possibility of giving an uncomfortable feeling to the passenger.
[0006]
Therefore, in the refrigeration cycle, the refrigerant pipe 80 on the discharge side and the suction side of the compressor 20 is connected by the bypass pipe 220, and the on-off valve 230 is provided in the bypass pipe 220. Thus, the time until the compressor 20 is restarted is shortened (for example, JP-A-8-85454).
[0007]
[Problems to be solved by the invention]
However, in the conventional vehicle air conditioner configured as described above, not only the normal refrigeration cycle but also the bypass pipe 220 and the release valve 230 are required, and piping work for attaching them is also required. This is not only an increase in manufacturing cost but also a problem in terms of workability.
[0008]
The present invention has been proposed in view of the above-described problems of the prior art, and without using a bypass pipe or the like, only a slight improvement is made to a normal refrigeration cycle, so that the discharge side and the suction side of the compressor can be reduced. An object of the present invention is to provide a passenger compartment air conditioner capable of preventing the occurrence of an excessive pressure difference of the refrigerant.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by the following means.
[0010]
(1) A refrigeration cycle in which a compressor, a condenser, a flow rate control unit, and an evaporator are connected by a refrigerant pipe so as to form a closed circuit, and when the compressor is stopped, from the discharge side of the compressor to the flow rate control unit. In the vehicle air conditioner configured to eliminate the pressure difference between the high pressure region and the low pressure region from the flow rate control unit to the suction side of the compressor , the flow rate control unit includes a valve body, a valve body, A partition wall formed so as to block a flow path through which the refrigerant flows, a diaphragm valve contacting and separating from the partition wall to open and close the flow path, and a pressure of the refrigerant acting above and below the diaphragm valve. A control unit for controlling, and a throttle pipe provided so as to penetrate the partition wall, and the diaphragm valve is moved by membrane control by pressure control by the control unit. A vehicle air conditioner characterized in that the flow path is opened by separating the partition wall and the pressure difference is eliminated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a passenger compartment air conditioner according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of an electromagnetic valve constituting the flow rate control unit shown in FIG. 1, and FIG. (B) shows the aperture state. In these drawings, the same reference numerals are used for members common to the reference numerals used in FIG.
[0013]
In the passenger compartment air conditioner 10 shown in FIG. 1, the refrigerant discharged from the compressor 20 passes through the condenser 30, the sub-capacitor 40, the liquid receiver 50, the flow rate control unit 60 including an electromagnetic valve, and the evaporator 70. The condenser 30 is provided with a fan 31 close to the condenser 30, and the refrigerant pipe 80 upstream of the compressor 20 is provided with an accumulator 21 that prevents the refrigerant from flowing backward from the compressor 20. Yes.
[0014]
In addition, the unit case 90 provided in the passenger compartment has an intake unit 120, a cooler unit 130 similar to the vehicle air conditioner shown in FIG. 3 described above from the upstream side in the air flow direction (indicated by a white arrow). It is formed by connecting the heater units 140 in series.
[0015]
Although not shown, on the outlet side of the air passage 91, various outlets from which conditioned air is blown out toward a predetermined part in the passenger compartment (for example, a differential outlet that blows out air for clearing the fogging of the window, an occupant) A vent outlet for blowing cool air toward the upper body of the body, a foot outlet for blowing warm air toward the feet of the passengers, and the like.
[0016]
The refrigerant compressed by the compressor 20 is radiated and liquefied by the capacitor 30, further radiated by the sub-capacitor 40, expanded by the flow rate control unit 60, guided into the evaporator 70, and returned to the compressor 20.
[0017]
Therefore, the air in the air passage 91 flows down after being cooled by the evaporator 70, and is branched by the mix door 150 into an air flow flowing through the sub-capacitor 40 and an air flow bypassing the sub-capacitor 40. And is blown out into the vehicle compartment from each of the outlets.
[0018]
Here, in general, in the refrigeration cycle, a region between the discharge side of the compressor 20 and the flow rate control unit 60 is a high pressure region, and a region between the flow rate control unit 60 and the suction side of the compressor 20 is a low pressure region. In the present embodiment, the pressure difference between the discharge side and the suction side of the compressor 20 is eliminated by improving the portion of the flow rate control unit 60 that partitions the high pressure region and the low pressure region.
[0019]
More specifically, the flow control unit 60 of the present embodiment is configured by an electromagnetic valve that can selectively switch the refrigerant flow between an open state and a throttle state, and selectively operates the valve. Thus, the pressure difference between the high pressure region and the low pressure region of the refrigeration cycle is eliminated, and an excessive differential pressure is not generated between the discharge side and the suction side of the compressor 20.
[0020]
As shown in FIG. 2, the flow rate control unit 60 includes a valve main body 170 provided in the lower part and a control part 180 provided in the upper part, and a diaphragm provided in the main flow path 171 of the valve main body 170. The valve 172 is operated by the control unit 180 to control the amount of refrigerant flowing through the main flow path 171.
[0021]
The control unit 180 includes a pilot valve 181 that opens and closes a pilot port 178 described later, a plunger 182 that operates the pilot valve 181, and a coil 183 that generates an electromagnetic force that drives the plunger 182.
[0022]
The plunger 182 is normally biased downward by a spring 184 and is configured to close the pilot port 178 by pressing a pilot valve 181 supported by a support spring 185 with a pilot needle 186.
[0023]
When the plunger 182 is pulled up by the electromagnetic force generated by energization of the coil 183, the pilot valve 181 becomes free and the pilot port 178 is opened.
[0024]
The main channel 171 has a partition wall 173 so as to block between the first connection port 174 into which the refrigerant from the refrigerant pipe 80 is introduced and the second connection port 175 through which the refrigerant flows out to the refrigerant pipe 80. The diaphragm wall 173 is provided with a throttle tube 176.
[0025]
The throttle tube 176 is composed of an orifice tube having a predetermined inner diameter D and length L that is press-fitted and fixed to the partition wall 173 so as to be parallel to the flow direction of the refrigerant flowing in the main flow path 171. However, the present invention is not limited to this, and any type can be used as long as the diaphragm valve 172 can flow the refrigerant beyond the partition wall 173 when the main flow path 171 is closed. For example, it may be configured by opening a through hole in the partition wall 173.
[0026]
Here, in the diaphragm valve 172, the valve seal portion located in the center moves up and down according to the pressure difference between the upper surface side and the lower surface side, and the main flow path 171 is opened and closed by the contact state with the partition wall 173. Further, a pressure equalizing hole 177 that communicates the upper surface side and the lower surface side is formed in the peripheral portion. The refrigerant that has passed through the pressure equalizing hole 177 is guided to the second connection port 175 through the pilot port 178.
[0027]
Therefore, the open state (fully open state) and the closed state of the main flow path 171 can be selected by turning on / off the power supply to the coil 183, and the differential pressure between the high pressure region and the low pressure region can be easily eliminated. Will be able to.
[0028]
However, even in the closed state, the throttle pipe 176 provided in the main flow path 171 is not in a completely closed state, but is in a throttle state in which the refrigerant passage is slightly opened, and the predetermined throttle throttled by the throttle pipe 176 is achieved. A flow of refrigerant is flowed.
[0029]
Note that if the inner diameter D and the length L of the throttle tube 176 are appropriately selected, the refrigerant flow rate characteristics of the flow rate control unit 60 can be adjusted.
[0030]
Next, the operation will be described.
(Cooling operation)
When performing the cooling operation, as shown in FIG. 2B, the diaphragm valve 172 of the flow rate control unit 60 is closed and the throttle pipe 176 is in the throttle state. That is, when the power supply to the coil 183 is turned off, the plunger 182 and the pilot needle 186 are pressed downward by the spring 184, the pilot valve 181 is pushed down, and the pilot port 178 is closed.
[0031]
As a result, the high-pressure refrigerant (pressure PH) flowing in from the first connection port 174 in the direction of the arrow enters the diaphragm chamber 179 through the pressure equalizing hole 177 of the diaphragm valve 172 (pressure PM), but the pilot valve 181 is closed. Therefore, it does not flow to the pilot port 178, but acts in the direction of pushing down the diaphragm valve 172 . Here, PH and PM are substantially equal. However, if the pressure of the second connection port 175 portion is PL, PM> PL.
[0032]
Therefore, the lower pressure (PH and PL act) is lower than the upper pressure (PM) of the diaphragm valve 172, and the diaphragm valve 172 is pushed down by this differential pressure, the main flow path 171 is closed and the refrigerant flow is reduced. Try to stop the flow.
[0033]
However, in the present embodiment, since the throttle pipe 176 that communicates the first connection port 174 and the downstream side of the main flow path 171 is provided, the high-temperature and high-pressure refrigerant from the first connection port 174 is throttled. It is adiabatically expanded by the valve 176 to be in a low temperature and low pressure state.
[0034]
Therefore, in this state, the refrigerant condensed by the capacitor 30 and the sub-capacitor 40 is stored to some extent by the liquid receiver 50 and then adiabatically expanded in the flow rate control unit 60 to be in a low temperature and low pressure state and led to the evaporator 70. Here, the normal cooling operation of evaporating is performed.
[0035]
As a result, the air sent from the intake unit 120 is cooled by the evaporator 70 and flows down in the air passage 91, and when the position of the mix door 150 is set at, for example, an intermediate position, a part of the air is sent. The remainder flows to the sub-capacitor 40 side, bypassing the sub-capacitor 40 with cold air, mixed with warm air heated by the sub-capacitor 40, and blown into the vehicle interior as an air flow of a predetermined temperature. The cooling operation will be performed.
[0036]
(Compressor stopped)
On the other hand, when the compressor 20 is stopped, the partitioning effect of the flow rate control unit 60 causes the compressor discharge side to the flow rate control unit 60 to be a high pressure region, and the flow rate control unit 60 to the compressor suction side becomes the low pressure region. Then, since the means for eliminating the partition effect of the flow rate control unit 60 is provided, an excessive pressure difference between the high pressure region and the low pressure region can be quickly resolved.
[0037]
That is, as shown in FIG. 2A, a current is passed through the coil 183 of the flow rate control unit 60, and the plunger 182 is pulled up by the electromagnetic force to make the pilot valve 181 free. The high-pressure refrigerant (pressure PH) flowing in the direction of the arrow enters the diaphragm chamber 179 from the pressure equalizing hole 177 of the diaphragm valve 172, flows around the free pilot valve 181, and flows to the pilot port 178.
[0038]
Here, since the size of the pressure equalizing hole 177 is small with respect to the opening of the pilot valve 181, if the pressure of the diaphragm chamber 179 is PM, PH> PM, and the pressure of the second connection port 175 portion is PL. Then, PM and PL are almost equal.
[0039]
Therefore, the lower pressure (PH and PL act) is higher than the upper pressure (PM) of the diaphragm valve 172, and the diaphragm valve 172 is pushed up by this differential pressure, and the main flow path 171 is opened. The valve 60 is in an open state in which the refrigerant flows.
[0040]
Therefore, in this state, the refrigerant pressure in the refrigerant pipe 80 becomes uniform quickly. In particular, since the pressure does not require time for equalization unlike the temperature, it is possible to prevent an excessive pressure difference from occurring on the discharge side and the inflow side of the compressor 20 almost instantaneously, and the compressor 20 is restarted immediately. Will be able to.
[0041]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.
For example, in the above-described embodiment, the flow rate control unit 60 having a differential pressure elimination function is incorporated into a device that can perform only the cooling operation, but the refrigerant is provided by providing a circuit switching valve in the refrigeration cycle. Needless to say, the present invention can also be applied to an apparatus in which the flow of the air is reversed so that an air conditioning operation can be performed.
[0042]
【The invention's effect】
As described above, according to the first aspect of the present invention, the high-pressure side and the low-pressure side of the cooling cycle are partitioned without providing a separate bypass pipe between the discharge side and the suction side of the compressor. When the compressor stops in the flow control unit itself, a means to eliminate the pressure difference between the high pressure side and the low pressure side of the cooling cycle is provided, so if the flow control unit is operated and switched to the open state when the compressor stops, the high pressure of the cooling cycle The pressure difference between the side and the low pressure side can be quickly eliminated.
[0043]
As a result, an excessive pressure difference between the discharge side and the suction side of the compressor is quickly eliminated, and the compressor can be restarted quickly.
[0044]
Further, in this manner, it is not necessary to provide a bypass pipe to connect the the discharge side of the compressor and the suction side as in the conventional device, the device structure is simplified, and improved workability during manufacturing, Overall, the manufacturing cost can be reduced.
[0045]
According to the second aspect of the present invention, the differential pressure is eliminated by using the diaphragm valve of the flow rate control unit that controls the flow rate of the refrigerant using a diaphragm valve or the like. In addition to improving the assembly workability, it is easy to switch between the throttle state and the open state of the flow control unit when the refrigeration cycle operation is performed and when the compressor is stopped.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.
2A and 2B are longitudinal sectional views showing a flow rate control unit according to the present embodiment shown in FIG. 1, in which FIG. 2A shows an open state, and FIG. 2B shows a throttle state.
FIG. 3 is a schematic configuration diagram showing a conventional air conditioner.
[Explanation of symbols]
20 ... Compressor,
30: Capacitor,
60 ... Flow control unit,
70 ... Evaporator,
80 ... refrigerant piping,
170 ... valve body,
171 ... main flow path,
172 ... Diaphragm valve,
173 ... partition wall,
176 ... throttle tube,
180 ... control unit,
172 ... Diaphragm valve,
173 ... Partition wall.

Claims (1)

Compressor (20), a capacitor (30), the flow control unit (60), an evaporator (70) with a connection to formed by a refrigeration cycle so as to form a closed circuit by refrigerant piping (80), the compressor (20) When stopped, the pressure between the high pressure region from the discharge side of the compressor (20) to the flow control unit (60) and the low pressure region from the flow control unit (60) to the suction side of the compressor (20) In the vehicle air conditioner designed to eliminate the difference ,
The flow rate control unit (60) includes a valve body (170 ) and a partition wall (173 ) formed so as to block a flow path (171 ) through which the refrigerant provided in the valve body (170 ) flows. A diaphragm valve (172 ) that opens and closes the flow path (171 ) in contact with and away from the partition wall (173 ), and a control unit (180 ) that controls the pressure of the refrigerant acting above and below the diaphragm valve (172 ) ; the partition wall (173) choke pipe provided so as to penetrate the (176) and a, the control unit the diaphragm valve by the pressure control by the (180) (172) the partition wall was Makudo (173) The air conditioner for vehicles is characterized in that the flow path (171 ) is opened by separating them from each other to eliminate the pressure difference.

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