JP4428290B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention is for a vehicle having a hot gas bypass function in which high-pressure and high-temperature gas refrigerant discharged from a compressor is decompressed and led to an evaporator, and the evaporator is used as a radiator for the gas refrigerant to heat air. The present invention relates to an air conditioner, and particularly relates to recovery control of refrigerant and oil that stagnate on the condenser side at low temperatures.

Conventionally, as this type of vehicle air conditioner, for example, before starting the heating mode by hot gas bypass, after the cooling mode operation is turned on for a predetermined time, the cooling operation is performed by turning off the compressor operation for a predetermined time, and thereafter An apparatus is known that has a recovery control for recovering the refrigerant on the condenser side to the evaporator side by performing the operation in the heating mode (see, for example, Patent Document 1).
JP 2003-322420 A

  However, according to Patent Document 1, the recovery time for securing the amount of refrigerant necessary for hot gas operation is as shown in FIG. 5 of Patent Document 1, with the compressor operation time (ON time) and the stop time (OFF time). ) Is obtained from the relationship between the outside air temperature and the refrigerant recovery time.

  More specifically, the recovery time when the compressor is operated is changed according to the outside air temperature, and the recovery time when the compressor is stopped is set to a predetermined time regardless of the outside air temperature. That is, the recovery time is a combination of a predetermined time for operating the compressor and a predetermined time for stopping the compressor.

  However, according to the research by the inventors, in an apparatus having a condenser that is exposed to the outside air while a vehicle such as an automobile is running, for example, at a very low outside temperature of about −30 ° C., all the refrigerant and It was found that the oil fell asleep and no refrigerant or oil remained on the hot gas cycle side.

  Under such circumstances, it has been found that the amount of refrigerant required for hot gas operation can be recovered to the hot gas cycle side by performing the recovery control which is a feature of Patent Document 1. However, at low temperatures where the outside air temperature is higher than about −30 ° C., the refrigerant just stagnates in the refrigerated cycle and only a small amount of refrigerant or oil remains on the hot gas cycle side. I found it.

  At this time, it has been found that the amount of refrigerant required for hot gas operation can be recovered to the hot gas cycle side even during the recovery time of only a predetermined time during which the compressor is operated in the recovery control of Patent Document 1 above.

  In view of the above, an object of the present invention is to provide a vehicle air conditioner capable of shortening the recovery time for recovering the refrigerant sleeping in the cooled portion in the refrigeration cycle to the hot gas cycle side. It is to provide.

In order to achieve the above object, the technical means described in claim 1 and claim 2 are employed. That is, in the invention described in claim 1, the compressor (1) that compresses and discharges the refrigerant, the condenser (2) that condenses the refrigerant discharged from the compressor (1), and the condenser (2 ), The evaporator (4) for evaporating the refrigerant depressurized by the first depressurizer (3), and the discharge side of the compressor (1) directly. The hot gas bypass passage (18) connected to the inlet side of the evaporator (4), the communication between the discharge side of the compressor (1) and the inlet side of the condenser (2), and the discharge of the compressor (1) Switching valve means (14) for switching communication between the side and the inlet side of the hot gas bypass passage (18),
The inlet side of the condenser (2) is opened by the switching valve means (14) and the inlet side of the hot gas bypass passage (18) is closed to perform a normal cooling mode operation. Also, the switching valve means ( In the vehicle air conditioner that closes the inlet side of the condenser (2) by 14) and opens the inlet side of the hot gas bypass passage (18) to perform the heating mode operation by the hot gas bypass,
Prior to activation of the heating mode by hot gas bypass, after the cooling mode operation is turned on for a predetermined time when the outside air temperature is lower than the predetermined temperature, the cooling mode operation is turned off for the predetermined time, and then the heating mode operation is performed. First refrigerant recovery control means (6a) for recovering the sleeping refrigerant on the condenser (2) side to the evaporator (4) side;
When the outside air temperature is equal to or higher than the predetermined temperature, the cooling mode operation of the first refrigerant recovery control means (6a) is prohibited from being turned off for a predetermined time, and the refrigerant stagnated on the condenser (2) side is removed from the evaporator (4) side. And a second refrigerant recovery control means (6b) for recovery.

  According to the present invention, the recovery time of the first refrigerant recovery control means (6a) or the second refrigerant recovery control means (6b) is controlled according to the outside air temperature, so that the recovery time is longer than that of the prior art. It can be shortened.

  The invention according to claim 2 is characterized in that the predetermined temperature of the outside air temperature is about −30 ° C. More specifically, according to the present invention, at a low temperature of about −30 ° C. or more, the compressor (1) The amount of refrigerant necessary for hot gas operation can be recovered on the hot gas cycle side even with the recovery time only for a predetermined time to operate.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

  Hereinafter, a vehicle air conditioner according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the overall configuration of a vehicle air conditioner according to the present invention, and FIG. 2 is a schematic diagram showing the overall configuration of a cooling / heating switching valve 14 as switching valve means. FIG. 3 is a perspective view showing a mounting form in which the vehicle air conditioner is mounted on the vehicle, and FIGS. 4A and 4B show the operating state of the refrigerant recovery control operation which is the main part of the present invention. It is a time chart.

  As shown in FIG. 1, the vehicle air conditioner of the present embodiment includes a compressor 1, a condenser 2, a cooling side throttle 3 that is a first decompression device, an evaporator 4, and the like that are sequentially connected in an annular manner with refrigerant piping. It consists of a refrigeration cycle.

  The compressor 1 is driven by, for example, a water-cooled vehicle engine (not shown) via an electromagnetic clutch 1a. The discharge side of the compressor 1 is connected to the condenser 2 via a cooling / heating switching valve 14 which is switching valve means. The condenser 2 performs heat exchange between the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 and the outside air to condense. The condenser 2 is provided with an electric cooling fan (not shown), and thereby cooling air (outside air) is blown.

  And the liquid receiver 21 which stores the condensed high pressure refrigerant | coolant is provided in the exit side of the condenser 2, and the liquid refrigerant stored in the liquid receiver 21 introduce | transduces into the air_conditioning | cooling side aperture | throttle 3 which is a 1st pressure reduction device. So connected. The outlet side of the cooling side throttle 3 is connected to the evaporator 4 via a check valve 19.

  The outlet side of the evaporator 4 is connected to the suction side of the compressor 1 via a suction tank 5 serving as a gas-liquid separator. The suction tank 5 separates the gas-liquid of the refrigerant and stores the liquid refrigerant, and sucks the gas refrigerant and a small amount of liquid refrigerant (oil is dissolved) near the bottom to the compressor 1 side.

  On the other hand, a hot gas bypass passage 18 for bypassing the condenser 2 is provided between the discharge side of the compressor 1 and the inlet side of the evaporator 4, and the upstream end of the bypass passage 18 is a switching valve means. It is connected to the cooling / heating switching valve 14. As shown in FIG. 2, the cooling / heating switching valve 14 of the present embodiment is configured integrally with an electromagnetic valve 15, a differential pressure valve 16, and a heating side throttle 17 that is a second pressure reducing device.

  When the electromagnetic valve 15 is opened, the discharge side of the compressor 1 communicates with the inlet side of the condenser 2, and the gas refrigerant compressed by the compressor 1 is introduced to the condenser 2 side. The refrigerant circulates in the order of liquid receiver → cooling side throttle 3 → evaporator 4 → suction tank 5 → compressor 1 in order to perform cooling operation.

  On the other hand, when the compressor 1 is operated while the solenoid valve 15 is closed, the discharge side of the compressor 1 and the inlet side of the hot gas bypass passage 18 communicate with each other via the differential pressure valve 16. The differential pressure valve 16 opens when the pressure difference between the pressure on the discharge side of the compressor 1 and the pressure on the inlet side of the condenser 2 exceeds a predetermined value when the electromagnetic valve 15 is closed. ing.

  That is, when the pressure difference becomes a predetermined value or more, the gas refrigerant compressed by the compressor 1 is introduced to the hot gas bypass passage 18 side and the gas refrigerant circulates in the evaporator 4 so that the heating operation can be performed. In the present embodiment, the heating side throttle 17 is integrally formed in the cooling / heating switching valve 14. However, the present invention is not limited to this, and the heating side throttle 17 is configured by a fixed throttle such as an orifice or a capillary tube on the hot gas bypass passage 18 side. The switching valve 14 may be provided in series.

  The evaporator 4 is installed in an air conditioning case (not shown) for a vehicle, and cools air (vehicle interior air or outside air) blown by an electric blower (not shown) in the cooling mode. In the winter heating mode, the evaporator 4 serves as a radiator because the high-temperature refrigerant gas (hot gas) from the hot gas bypass passage 18 flows in and heats the air.

  Usually, in the air conditioning case, a hot water heating heat exchanger (not shown) that heats blown air using hot water (engine cooling water) from a vehicle engine (not shown) as a heat source downstream of the evaporator 4. The air-conditioned air is blown out from the air outlet provided on the downstream side of the heating heat exchanger into the passenger compartment.

  The air conditioning electronic control unit (ECU) 6 is composed of a microcomputer and its peripheral circuits, and performs arithmetic processing on the input signal in accordance with a preset first refrigerant recovery control program 6a and second refrigerant recovery control program 6b. Thus, ON / OFF of the electromagnetic clutch 1a, opening / closing of the electromagnetic valve 15 provided in the cooling / heating switching valve 14 and the operation of other electric devices are controlled, and constitutes the control means of the present invention.

  In the perspective view of the vehicle air conditioner mounted form shown in FIG. 3, the cooling / heating switching valve 14, the hot gas bypass passage 18, the check valve 19, and the cooling side throttle 3 shown in FIGS. It arrange | positions in the vicinity of the container 2, and is arrange | positioned so that they may comprise integrally.

  Next, the operation of the hot gas cycle of the vehicle air conditioner configured as described above will be described. Generally, this type of hot gas system bypasses the condensing part of the refrigeration cycle and operates in a low outside air temperature range different from the air conditioning (A / C) operation region.

  When the outside air temperature is low, the refrigerant and oil in the refrigeration cycle have a property of sleeping in a cold place in the refrigeration cycle. For this reason, it is conceivable that the refrigerant and oil are exposed to the outside air temperature, and a large amount of the refrigerant and oil fall into the condenser 2 having a large volume.

  Therefore, during the hot gas operation, it is necessary to recover the stagnation refrigerant from the condenser 2 into the hot gas cycle, and it is necessary to perform the refrigerant recovery for recovering the refrigerant from the condenser 2 before starting the hot gas operation. . However, when recovering the refrigerant, the amount of refrigerant and the amount of oil in the hot gas cycle are smaller than when appropriate, and operating the compressor 1 in this state has a great effect on the durability of the compressor 1.

  In the prior art (Japanese Patent Laid-Open No. 2003-322420), in a refrigerant shortage state requiring refrigerant recovery, the compressor 1 is turned on for a predetermined time after the cooling mode operation for recovering the minimum refrigerant is performed. There is a method of performing a cooling operation in which the operation is turned off for a predetermined time, and then performing a heating mode operation.

  However, according to the study by the inventors, in the above method, when the outside air temperature is extremely low, for example, about −30 ° C. or less, all the refrigerant and oil are exposed to the condenser 2 side exposed to the extremely low temperature. I have fallen asleep and no refrigerant remains on the hot gas cycle side. At this time, it has been found that if refrigerant recovery is performed by the above method, the refrigerant or oil that has fallen into the condenser 2 side can be recovered in the hot gas cycle.

  In addition, when the outside air temperature is a low temperature of about −30 ° C. or higher, for example, in the case of a low temperature of about −10 to −20 ° C., the refrigerant stagnates in the cooled place in the refrigeration cycle. It was found that a small amount of refrigerant remained. At this time, it has been found that, among the refrigerant recovery by the above method, the refrigerant amount necessary for the hot gas operation can be recovered to the hot gas cycle side only by turning on the cooling mode operation for a predetermined time.

  That is, when the outside air temperature is higher than the above-mentioned extremely low temperature, since there is a small amount of refrigerant in the hot gas cycle, only the cooling mode operation is turned on for a predetermined time in the above-described refrigerant recovery. The amount of refrigerant necessary for operation can be recovered on the hot gas cycle side.

  Therefore, in the present invention, the recovery time of the first refrigerant recovery control means 6a or the second refrigerant recovery control means 6b is controlled according to the outside air temperature, thereby shortening the recovery time compared to the prior art. To be able to do that.

  Specifically, a time chart when the outside air temperature is a predetermined temperature (for example, about −30 ° C.) or less is shown in FIG. 4A, and when the outside air temperature is a predetermined temperature (for example, about −30 ° C.) or more. A time chart is shown in FIG.

  The time chart shown in FIG. 4A is the recovery control by the first refrigerant recovery control means 6a, and the time chart shown in FIG. 4B is the recovery control by the second refrigerant recovery control means 6b.

  The first refrigerant recovery control means 6a that performs recovery control when the outside air temperature is equal to or lower than a predetermined temperature (for example, about −30 ° C.) is shown in FIG. 4 (a) when the user commands the heating mode desired. As shown, prior to hot gas operation, (B) the on-off valve 15 of the cooling / heating switching valve 14 is opened, and (A) the electromagnetic clutch 1 a is turned on to operate the compressor 1. Specifically, the cooling operation is performed for a predetermined time (for example, 20 seconds). Thereby, the refrigerant that has fallen into the condenser 2 by this cooling operation can be recovered in the hot gas cycle.

  Thereafter, in the cooling mode, (A) the electromagnetic clutch 1a is turned off to stop the driving of the compressor 1, and the cooling operation is performed for a predetermined time (for example, 30 seconds). As a result, the refrigerant with a margin for hot gas operation (H / G) is recovered in the hot gas cycle due to the pressure difference between the high pressure side on the condenser 2 side and the low pressure side on the evaporator 4 side in the refrigeration cycle. The

  After that, (B) the on-off valve 15 of the cooling / heating switching valve 14 is closed, and (A) the electromagnetic clutch 1a is turned on to drive the compressor 1 to perform the heating operation. Thereby, the heating operation by a hot gas cycle can be performed.

  Next, the second refrigerant recovery control means 6b, which performs recovery control when the outside air temperature is equal to or higher than a predetermined temperature (for example, about −30 ° C.), operates as shown in FIG. As shown in b), prior to the hot gas operation, (B) the on-off valve 15 of the air conditioning switching valve 14 is opened, and (A) the electromagnetic clutch 1a is turned on to operate the compressor 1. Specifically, the cooling operation is performed for a predetermined time (for example, 20 seconds). Thereby, the refrigerant | coolant which stagnate in the location cooled by this air_conditionaing | cooling operation | movement can be collect | recovered in a hot gas cycle.

  After that, (B) the on-off valve 15 of the cooling / heating switching valve 14 is closed, and (A) the electromagnetic clutch 1a is turned on to drive the compressor 1 to perform the heating operation. Thereby, the heating operation by a hot gas cycle can be performed.

  Therefore, in the second refrigerant recovery control means 6b, in the cooling mode of the first refrigerant recovery control means 6a, (A) the electromagnetic clutch 1a is turned off to stop the drive of the compressor 1 for a predetermined time. Since it is possible to omit the cooling operation (for example, for 30 seconds), the recovery time can be shortened as compared with the first refrigerant recovery control means 6a.

  According to the vehicle air conditioner according to the above-described embodiment, the cooling mode operation is turned on for a predetermined time when the outside air temperature is equal to or lower than a predetermined temperature (for example, about −30 ° C.) before the heating mode is activated by the hot gas bypass. After that, the cooling mode operation is turned off for a predetermined time, and then the heating mode operation is performed to recover the stagnant refrigerant on the condenser 2 side to the evaporator 4 side, and the outside air temperature is When the temperature is equal to or higher than a predetermined temperature (for example, about −30 ° C.), the operation of the cooling mode in the first refrigerant recovery control means 6a is prohibited from being turned off for a predetermined time, and the stagnant refrigerant on the condenser 2 side is moved to the evaporator 4 side. And a second refrigerant recovery control means 6b for recovery.

  According to this, the recovery time of the first refrigerant recovery control means 6a or the second refrigerant recovery control means 6b is controlled according to the outside air temperature, so that the recovery time can be shortened compared with the prior art. I can do it.

  Also. The predetermined temperature of the outside air temperature is about −30 ° C. More specifically, if it is at a low temperature of about −30 ° C. or more, the refrigerant or oil is slightly present on the hot gas cycle side. By remaining, the refrigerant amount necessary for hot gas operation can be recovered to the hot gas cycle side even during the recovery time of only a predetermined time for operating the compressor 1.

(Other embodiments)
In the above embodiment, the predetermined temperature of the outside air temperature is limited to about -30 ° C, but preferably about -30 ° C. More preferably, the temperature may be about −30 ° C.

It is a mimetic diagram showing the whole vehicle air-conditioner composition in one embodiment of the present invention. It is a schematic diagram which shows the whole structure of the air-conditioning switching valve 14 in one Embodiment of this invention. It is a perspective view which shows the mounting form which mounted the vehicle air conditioner in one Embodiment of this invention in the vehicle. (A) And (b) is a time chart which shows the operating state of the refrigerant | coolant collection | recovery control driving | operation which becomes the principal part of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Condenser 3 ... Cooling side throttling (1st decompression device)
4 ... Evaporator 6a ... First refrigerant recovery control means 6b ... Second refrigerant recovery control means 14 ... Air conditioning switching valve (switching valve means)
18 ... Hot gas bypass passage

Claims (2)

A compressor (1) for compressing and discharging refrigerant;
A condenser (2) for condensing the discharged gas refrigerant of the compressor (1);
A first decompression device (3) for decompressing the refrigerant condensed in the condenser (2);
An evaporator (4) for evaporating the refrigerant decompressed by the first decompression device (3);
A hot gas bypass passage (18) for connecting the discharge side of the compressor (1) directly to the inlet side of the evaporator (4);
The communication between the discharge side of the compressor (1) and the inlet side of the condenser (2) and the communication between the discharge side of the compressor (1) and the inlet side of the hot gas bypass passage (18) are switched. Switching valve means (14),
The switching valve means (14) opens the inlet side of the condenser (2) and closes the inlet side of the hot gas bypass passage (18) to perform a normal cooling mode operation. The air conditioning system for a vehicle which closes the inlet side of the condenser (2) by the switching valve means (14) and opens the inlet side of the hot gas bypass passage (18) to perform the heating mode operation by the hot gas bypass. In the device
Prior to activation of the heating mode by the hot gas bypass,
After the cooling mode operation is turned on for a predetermined time when the outside air temperature is equal to or lower than the predetermined temperature, the cooling mode operation is turned off for a predetermined time, and then the heating mode operation is performed to stagnation refrigerant on the condenser (2) side. First refrigerant recovery control means (6a) for recovering the refrigerant to the evaporator (4) side;
When the outside air temperature is equal to or higher than a predetermined temperature, the cooling mode operation of the first refrigerant recovery control means (6a) is prohibited from being turned off for a predetermined time, and the stagnation refrigerant on the condenser (2) side is removed from the evaporator ( 4) A vehicle air conditioner having second refrigerant recovery control means (6b) for recovery on the side.   The vehicle air conditioner according to claim 1, wherein the predetermined temperature of the outside air temperature is about -30 ° C.

Images