JP2013231522A - Heat pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress fluctuation of a heat supply amount even in defrosting.SOLUTION: A vehicle air conditioner 1 includes a first cycle 10 and a second cycle 20 providing a heat pump device. The first cycle 10 includes a former-stage compressor 13 and a latter-stage compressor 14. The second cycle 20 includes a former-stage compressor 23 and a latter-stage compressor 24. In a heating operation, the cycles 10, 20 are operated as a multistage compression cycle, and in a defrosting operation, the cycles 10, 20 are operated as single-stage compression cycles. When a defrosting operation is executed for one of the cycles, a control device 6 executes a heating operation for the other cycle. Further, the control device 6 controls the cycles 10, 20 so that the defrosting operation for the first cycle 10 and the defrosting operation for the second cycle 20 are not simultaneously executed. Thus, degradation of a heating capacity due to the defrosting operation can be suppressed. Further, high heating capacity and proper defrosting capacity can be obtained.

Description

  The present invention relates to a heat pump device that pumps heat by a refrigerant cycle.

  Patent documents 1-5 are disclosing the heat pump apparatus which pumps up heat with a refrigerant cycle. Such a heat pump device performs a defrosting operation in order to suppress or avoid blockage of the heat exchanger on the non-use side due to frost or ice. Further, some heat pump apparatuses include a cycle for performing a defrosting operation and a cycle for performing a heat pump operation. Such a heat pump device has an advantage that the supply of heat can be continued even during the defrosting operation.

JP-A-11-173712 JP 2006-116981 A JP 2008-96033 A JP 2008-209083 A JP 2010-236709 A

  The prior art offers advantages in the aspects they disclose. However, further improvements were sought to adjust the heat supply to the desired state. For example, even when the apparatus performs a defrosting operation, it has been required to suppress fluctuations in the heat supply amount.

  The present invention has been made in view of the above problems, and the object thereof is to defrost while continuing to supply heat, and to suppress fluctuations in the amount of heat supply even if defrosting is performed. It is providing the heat pump apparatus which can be performed.

  Another object of the present invention is to provide a heat pump device in which when one cycle performs a defrosting operation, the other one cycle can increase the amount of heat supplied.

  The present invention employs the following technical means to achieve the above object. It should be noted that the reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later as one aspect, and the technical scope of the present invention It is not limited.

  One of the disclosed inventions includes a plurality of cycles (10, 20) each including a front-stage compressor (13, 23) and a rear-stage compressor (14, 24) that can be operated as a multistage compression type cycle and functioning as a heat pump. And a control device (6) for switching the operation mode of each of the plurality of cycles to a heat pump operation and a defrosting operation, and the control device (6) includes a controller for the plurality of cycles (10, 20). A schedule unit (161, HTM1, HTM2) that sequentially sets the permission periods (PD1, PD2) of the frost operation without overlapping each other, a heat pump operation unit (176) that simultaneously executes the heat pump operation by a plurality of cycles, A defrosting operation that performs a defrosting operation of one cycle in response to the schedule unit and simultaneously performs a heat pump operation of another cycle. And a rolling portion (180, 190), a plurality of cycles (10, 20) when the heat pump operation is performed, characterized in that it is operated as a multistage compression type cycle.

  According to this structure, the permission part of the defrost operation for a some cycle is given in order, without mutually overlapping by a schedule part. When one cycle of defrosting operation is executed, the other one cycle of heating operation is executed. Therefore, it is avoided that a plurality of cycles are defrosted at the same time. Each of the plurality of cycles is operated as a multistage compression type cycle when the heat pump operation is performed. Therefore, high heat supply capability is provided. Even when one cycle of defrosting operation is performed and another one cycle of heating operation is performed, the other one cycle is operated as a multistage compression type cycle. Therefore, the fall of the heat supply capability resulting from a defrost operation can be suppressed.

It is a block diagram which shows the vehicle air conditioner which concerns on 1st Embodiment of this invention. It is a block diagram which shows the heating operation of the cycle of 1st Embodiment. It is a block diagram which shows the defrost driving | operation of the cycle of 1st Embodiment. It is a flowchart which shows a part of control of 1st Embodiment. It is a flowchart which shows a part of control of 1st Embodiment. It is a flowchart which shows a part of control of 1st Embodiment. It is a timing diagram which shows the waveform of the control timer of 1st Embodiment. It is a flowchart which shows a part of control of 1st Embodiment. It is a timing diagram which shows an example of the action | operation of 1st Embodiment. It is a flowchart which shows a part of control of 2nd Embodiment of this invention. It is a timing diagram which shows an example of the action | operation of 2nd Embodiment. It is a block diagram which shows the defrost operation of the cycle of 3rd Embodiment of this invention.

  Hereinafter, a plurality of modes for carrying out the disclosed invention will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Further, in the following embodiments, the correspondence corresponding to the matters corresponding to the matters described in the preceding embodiments is indicated by adding reference numerals that differ only by one hundred or more, and redundant description may be omitted. . Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

(First embodiment)
In FIG. 1, in 1st Embodiment of this invention, the vehicle air conditioner 1 provided with a heat pump apparatus is provided. The vehicle air conditioner 1 adjusts the indoor temperature of the road traveling vehicle. The vehicle air conditioner 1 is mounted on a bus vehicle.

  The vehicle air conditioner 1 includes an air conditioning unit 2 installed on the roof of the vehicle. The air conditioning unit 2 includes an indoor unit part 2a, a machine room part 2b, and an outdoor unit part 2c. The indoor unit part 2a, the machine room part 2b, and the outdoor unit part 2c are configured as one unit by being mounted on a common chassis and / or covered with a cover having a sense of unity.

  The indoor unit portion 2a accommodates components for exchanging heat with indoor air. The indoor unit portion 2a provides a duct through which air for air conditioning flows. The indoor unit portion 2a includes a suction duct (IN) 3a for introducing air from the room, and blowout ducts (OUT) 3b, 3c for supplying air into the room. For example, the blowing duct 3b is provided on the right side of the vehicle. For example, the blowout duct 3b is provided on the left side of the vehicle. The air conditioning unit 2 includes a plurality of indoor fans 4a and 4b that send air from the suction duct 3a to the outlet ducts 3b and 3c. The blower 4a sends air from the suction duct 3a to the blowout duct 3b. The blower 4b sends air from the suction duct 3a to the blowout duct 3c.

  The machine room portion 2b accommodates parts including a compressor of cycles 10 and 20 described later. The outdoor unit portion 2c accommodates parts for exchanging heat with outdoor air. The air conditioning unit 2 includes outdoor fans 5a and 5b that introduce outdoor air and send it to a heat exchanger described later. The outdoor unit portion 2c promotes heat exchange by wind obtained by traveling of the vehicle and wind obtained by the fans 5a and 5b.

  The air conditioning unit 2 includes a first cycle (CYL1) 10 and a second cycle (CYL2) 20. The cycles 10 and 20 are vapor compression refrigeration cycle apparatuses. The first cycle 10 and the second cycle 20 have the same components. The cycles 10 and 20 can function as a heat pump. The cycles 10 and 20 provide a heat pump cycle for heating that heats the interior of the vehicle using at least air outside the vehicle as a heat source. Cycles 10 and 20 provide a heat pump device. Cycles 10 and 20 can execute a heating operation for heating indoor air. The cycles 10 and 20 pump up the heat of the outdoor air and heat the indoor air. Cycles 10 and 20 provide at least a heat pump cycle for heating. The cycles 10 and 20 may additionally provide a refrigeration cycle for cooling.

  The cycles 10 and 20 are configured to be operable as a multistage compression type cycle. The multistage compression type cycle can provide a high heating capacity even when the outdoor temperature is low. The cycles 10 and 20 are configured so that the room can be heated even at −20 ° C., for example.

  The plurality of cycles 10 and 20 are arranged in parallel on the air conditioning function provided by the vehicle air conditioner 1. That is, each of the plurality of cycles 10 and 20 can heat the room. The plurality of cycles 10 and 20 are used for indoor heating, which is a common heat load. Specifically, the plurality of cycles 10 and 20 are (1) heating only by the first cycle 10, (2) heating only by the second cycle, and (3) both by the first cycle 10 and the second cycle 20. Three heating operations can be provided, including heating.

  In FIG. 1, the first cycle 10 includes an indoor heat exchanger (IN-HEX1) 11 and an outdoor heat exchanger (EX-HEX1) 12. The indoor heat exchanger 11 is disposed in the indoor unit portion 2a. The indoor heat exchanger 11 is disposed on a passage of air blown by the blower 4a. The outdoor heat exchanger 12 is disposed in the outdoor unit portion 2c. The outdoor heat exchanger 12 is arranged on a passage of air blown by the blower 5a.

  The first cycle 10 includes a plurality of compressors 13 and 14. The plurality of compressors 13 and 14 are electric compressors including an electric motor. The several compressors 13 and 14 are arrange | positioned at the machine room part 2b. When the first cycle 10 is operated as a multistage compression type cycle, the compressors 13 and 14 are arranged in series on the refrigerant passage of the first cycle 10. The first cycle 10 includes a front-stage compressor (PCMP1) 13 and a rear-stage compressor (SCMP1) 14 that can be operated as a multistage compression type cycle. When the first cycle 10 is operated as a multistage compression type cycle, the refrigerant is compressed by the front-stage compressor 13 and then further compressed by the rear-stage compressor 14. Further, when the first cycle 10 is operated as a single-stage compression type cycle, the compressors 13 and 14 are arranged in parallel or selectively on the refrigerant passage of the first cycle 10. The first cycle 10 includes other functional components such as a decompressor.

  The second cycle 20 includes an indoor heat exchanger (IN-HEX2) 21 and an outdoor heat exchanger (EX-HEX2) 22. The indoor heat exchanger 21 is disposed in the indoor unit portion 2a. The indoor heat exchanger 21 is disposed on the passage of the air blown by the blower 4a. The outdoor heat exchanger 22 is disposed in the outdoor unit portion 2c. The outdoor heat exchanger 22 is arranged on a passage of air blown by the blower 5a.

  The second cycle 20 includes a plurality of compressors 23 and 24. The plurality of compressors 23 and 24 are electric compressors including an electric motor. The some compressors 23 and 24 are arrange | positioned at the machine room part 2b. When the second cycle 20 is operated as a multistage compression type cycle, the compressors 23 and 24 are arranged in series on the refrigerant passage of the second cycle 20. The second cycle 20 includes a front stage compressor (PCMP2) 23 that can be operated as a multistage compression type cycle, and a rear stage compressor (SCMP2) 24. When the second cycle 20 is operated as a multistage compression type cycle, the refrigerant is compressed by the former compressor 23 and then further compressed by the latter compressor 24. Further, when the second cycle 20 is operated as a single-stage compression type cycle, the compressors 23 and 24 are arranged in parallel or selectively on the refrigerant passage of the second cycle 20. The second cycle 20 includes other functional components such as a decompressor.

  The cycles 10 and 20 have a defrosting function for reducing or removing frost or ice attached to the outdoor heat exchangers 12 and 22. The cycles 10 and 20 can suppress or avoid blockage of the outdoor heat exchangers 12 and 22 with frost or ice by performing a defrosting operation.

  The defrosting function can be provided by a heat supply function according to the cycles 10 and 20, or an external heat source such as an electric heater. In this embodiment, the cycles 10 and 20 themselves have a defrosting operation mode for supplying heat to the outdoor heat exchangers 12 and 22. The cycles 10 and 20 are defrosting operations such as a reverse operation (cooling operation) in which the outdoor heat exchangers 12 and 22 function as radiators, and a hot gas operation for supplying hot gas refrigerant to the outdoor heat exchangers 12 and 22. A mode can be provided. In this embodiment, cycles 10 and 20 provide a defrosting operation mode by reverse operation.

  The vehicle air conditioner 1 includes a control device (CNTR) 6. The control device 6 switches the operation modes of the plurality of cycles 10 and 20 to a heat pump operation, that is, a heating operation and a defrosting operation. The control device 6 is provided by a microcomputer provided with a computer-readable storage medium. The storage medium stores a computer-readable program non-temporarily. The storage medium can be provided by a semiconductor memory or a magnetic disk. The program is executed by the control device 6 to cause the control device 6 to function as a device described in this specification, and to cause the control device 6 to function so as to execute the control method described in this specification. The means provided by the control device 6 can also be referred to as a functional block or module that achieves a predetermined function.

  The vehicle air conditioner 1 includes a plurality of sensors. The plurality of sensors can include a temperature setter that sets a target temperature in the room and a temperature sensor that detects the temperature in the room. The plurality of sensors include a frost sensor (FRSN1) 7 and a frost sensor (FRSN2) 8. The frost sensor 7 detects the temperature of the outdoor heat exchanger 12. The frost sensor 8 detects the temperature of the outdoor heat exchanger 22. The frost adheres and grows when the temperature of the outdoor heat exchangers 12 and 22 falls below a predetermined threshold temperature. Therefore, it can be considered that frost adheres and grows easily when the detected temperature of the frost sensors 7 and 8 is lower than the threshold temperature. Specifically, frost adheres and grows when there is sufficient humidity in the outside air. For example, when the outside air temperature is about −5 ° C., the outside air contains a relatively large amount of water vapor. Moreover, when the outside air temperature is about −5 ° C., the outdoor heat exchangers 12 and 22 are significantly lower than the outside air temperature for heating. For this reason, when the outside air temperature is in the range of several degrees including −5 ° C., frost adheres to the outdoor heat exchangers 12 and 22 and is likely to grow.

  The control device 6 provides a temperature control unit. The temperature control unit controls the air conditioning unit 2 including the cycles 10 and 20 so that the room temperature approaches and maintains the indoor temperature. Furthermore, the control apparatus 6 provides a defrost control part. The defrost control unit controls the air conditioning unit 2 including the cycles 10 and 20 to reduce or eliminate frost when the frost sensors 7 and 8 detect adhesion of frost. The defrost control unit controls the plurality of cycles 10 and 20 such that only a part of the plurality of cycles 10 and 20 performs a defrosting operation. The defrost control unit controls the other one cycle to perform the heating operation when the one cycle performs the defrost operation. A defrost control part sets an operation schedule so that all the some cycles 10 and 20 do not carry out a defrost operation simultaneously. When one cycle performs a defrosting operation after one cycle performs a defrosting operation, the defrosting control unit sets an operation schedule so that both cycles perform a heating operation between them.

  As shown in FIGS. 2 and 3, the cycles 10 and 20 include pressure reducers 15 and 25, accumulators 16 and 26, two-way four-way valves 17 and 27, and on-off valves 18 and 28. The decompressors 15 and 25 decompress the refrigerant. The accumulators 16 and 26 have a function as a gas-liquid separator for supplying gas refrigerant to the compressor and a function as a tank for storing surplus refrigerant. The four-way valves 17 and 27 and the on-off valves 18 and 28 can be operated by electromagnetic actuators.

  The four-way valve 17 switches the arrangement of the compressors 13 and 14 in the cycle 10 so that the refrigerant flow direction in the cycle 10 is reversed. The four-way valve 17 and the on-off valve 18 provide a flow path switching device for reversing the refrigerant flow direction in the cycle 10.

  The four-way valve 27 switches the arrangement of the compressors 23 and 24 in the cycle 20 so that the refrigerant flow direction in the cycle 20 is reversed. The four-way valve 27 and the on-off valve 28 provide a flow path switching device for reversing the refrigerant flow direction in the cycle 20.

  As illustrated in FIGS. 2 and 3, the cycle 10 is configured as a cycle capable of reverse operation. FIG. 2 shows cycles 10 and 20 in the heating operation (HEAT). The plurality of cycles 10 and 20 are operated as a multistage compression type cycle when the heat pump operation is executed. In the heating operation, the four-way valves 17 and 27 and the on-off valves 18 and 28 connect the front-stage compressors 13 and 23 and the rear-stage compressors 14 and 24 in series in the cycles 10 and 20. The refrigerant evaporated in the outdoor heat exchangers 12 and 22 passes through the accumulators 16 and 26 and is then compressed by the pre-stage compressors 13 and 23. The refrigerant is further compressed by the subsequent compressors 14 and 24. The high-temperature and high-pressure refrigerant is supplied to the indoor heat exchangers 11 and 21 and heats the air supplied to the room. This provides room heating. The refrigerant is decompressed by the decompressors 15 and 25 and is supplied to the outdoor heat exchangers 12 and 22 again.

  In the heating operation, the four-way valves 17 and 27 are in the ON state. In the heating operation, the on-off valves 18 and 28 are in an OFF state, specifically, a closed state. In the heating operation, the fans 4a and 4b are in the ON state. The air volume of the blowers 4a and 4b is variably controlled so that an appropriate air volume suitable for the heating load is provided. In the heating operation, the fans 5a and 5b are in the ON state. The amount of air blown by the blowers 5a and 5b is variably controlled so that an appropriate amount of air passes through the outdoor heat exchangers 12 and 22. In the heating operation, the compressors 13, 23, 14, and 24 are in the ON state, that is, the operation state. The rotation speeds of the compressors 13, 23, 14, and 24 are variably controlled so as to provide an appropriate heating capacity that matches the heating load.

  FIG. 3 shows cycles 10 and 20 in the defrosting operation (DEFROST). In the defrosting operation, the four-way valves 17 and 27 and the on-off valves 18 and 28 connect the front compressors 13 and 23 and the rear compressors 14 and 24 in parallel in the cycles 10 and 20. The refrigerant evaporated in the indoor heat exchangers 11 and 21 branches after passing through the accumulators 16 and 26. One of the branched refrigerants is compressed by the pre-stage compressors 13 and 23. The other branched refrigerant is compressed by the rear stage compressors 14 and 24. The high-temperature and high-pressure refrigerant is supplied to the outdoor heat exchangers 12 and 22 and heats the outdoor heat exchangers 12 and 22. Thereby, the frost adhering to the outdoor heat exchangers 12 and 22 is melted. The refrigerant is decompressed by the decompressors 15 and 25 and supplied to the indoor heat exchangers 11 and 21 again.

  In the defrosting operation, the four-way valves 17 and 27 are in the OFF state. In the defrosting operation, the on-off valves 18 and 28 are in an ON state, specifically, in a valve open state. In the defrosting operation, the blowers 4a and 4b are in an OFF state or a small air volume state (Lo). The amount of air blown by the blowers 4a and 4b is limited to zero or a small amount of air in order to suppress the blowing of cool air into the room. In the defrosting operation, the blowers 5a and 5b are in the OFF state. The amount of air blown from the blowers 5a and 5b is limited to zero or a small air amount in order to suppress the cooling of the outdoor heat exchangers 12 and 22 by the outside air. In the defrosting operation, the compressors 13, 23, 14, and 24 are in the ON state, that is, in the operating state. The number of rotations of the compressors 13, 23, 14, and 24 is fixedly controlled or variably controlled so that the temperature of the outdoor heat exchangers 12 and 22 becomes a temperature at which frost is melted.

  The plurality of cycles 10 and 20 are operated as a single-stage compression type cycle when the defrosting operation is executed. According to this configuration, it is possible to execute an appropriate defrost while suppressing an excessive temperature increase for defrosting or a local temperature increase.

  When one cycle performs the defrosting operation and the other one cycle performs the heating operation, the rotation speed of the compressor of the cycle in which the heating operation is performed is controlled so as to suppress the temperature drop in the room. In this case, for example, it is possible to perform fixed control so that the rotation speed of the compressor that performs the heating operation becomes a fixed rotation speed. The rotation speed of the compressor that performs the heating operation can be set so as to suppress an excessive decrease in the temperature of the air blown into the room. Moreover, the rotation speed of the compressor that performs the heating operation can be variably controlled so that the indoor temperature approaches the target temperature and is maintained. Further, the rotation speed of the compressor that performs the heating operation is higher than the rotation speed before the defrosting operation is started so as to suppress the decrease in the heating capacity due to the defrosting operation of one cycle. Can be controlled. For example, the rotation speed of the compressor that performs the heating operation can be controlled to the maximum rotation speed.

  FIG. 4 shows the frost formation determination process 140 for the first cycle 10. In the frosting determination process 140, the control device 6 determines whether or not the amount of frost adhering to the outdoor heat exchanger 12 is an amount that requires defrosting. In other words, the control device 6 determines whether or not defrosting is necessary. When frost formation that requires defrosting is determined, control device 6 sets a flag for requesting defrosting operation. In other words, the control device 6 requests the defrosting operation by the frosting determination process 140.

  In step 141, the control device 6 determines whether or not the detected temperature FR1 of the frost sensor 7 is lower than the threshold temperature Tth. If FR1 <Tth, that is, a positive result, branch to Y. If FR1 ≧ Tth, that is, a negative result, branch to N. When the detected temperature FR1 is relatively high, the control device 6 proceeds to step 144, resets the timer and the flag, and ends the process. When the detected temperature FR1 is lower than the threshold temperature Tth, the routine proceeds to step 142.

  In step 142, the control device 6 starts timing by the timer FTM1. The timer FTM1 is a timer for estimating the amount of frost formation. The timer FTM1 is used to determine that the state in which the detected temperature FR1 is lower than the threshold temperature Tth continues for a predetermined time. When FR1 <Tth continues beyond a predetermined time, it can be estimated that frost exceeding a predetermined amount adheres to the outdoor heat exchanger 12.

  In step 143, the control device 6 determines again whether or not the detected temperature FR1 is lower than the threshold temperature Tth. In the case of FR1 ≧ Tth, the control device 6 proceeds to step 144, resets the frosting timer and the flag, and ends the process. That is, when the detected temperature FR1 returns to a high temperature during measurement by the frost timer FTM1, the frost determination is reset. If FR1 <Tth in step 143, the process proceeds to step 145.

  In step 145, the control device 6 determines whether or not the timer FTM1 exceeds the threshold time Fth. If FTM1 ≦ Fth, the process returns to step 143. If FTM1> Fth, the process proceeds to step 146. In step 146, control device 6 sets flag FLG1. The flag FLG1 indicates that the defrosting operation is necessary when in the set state. The flag FLG2 indicates that the defrosting operation is unnecessary when in the reset state.

  FIG. 5 shows the frosting determination process 150 for the second cycle 20. Steps 151 to 156 correspond to steps 141 to 146. In steps 151 to 156, the control device 6 executes the same processing as that of steps 141 to 146 for the second cycle 20.

  FIG. 6 shows the control timer process 160. In step 161, time measurement by the control timers HTM1 and HTM2 is started. The control timer HTM1 defines a first period PD1 in which the defrosting operation for the first cycle 10 can be performed. The control timer HTM2 defines the second period PD2 in which the defrosting operation for the second cycle 20 can be performed. In other words, the control timer HTM1 defines a period during which execution of the defrosting operation for the first cycle 10 is prohibited. The control timer HTM2 defines a period during which execution of the defrosting operation for the second cycle 20 is prohibited. The first period PD1 and the second period PD2 are set so as not to overlap. Since the control timers HTM1 and HTM2 function continuously during the heating period, they are also called heating timers.

  FIG. 7 shows waveforms of the control timers HTM1 and HTM2. The control timers HTM1 and HTM2 output a rectangular wave having a predetermined cycle and a predetermined duty ratio.

  The first control timer HTM1 repeats ON and OFF at a predetermined cycle. The first control timer HTM1 defines a first period PD1 in which the defrosting operation for the first cycle 10 can be performed by the ON period.

  The second control timer HTM2 repeats ON and OFF at a predetermined cycle. The second control timer HTM2 defines the second period PD2 in which the defrosting operation for the second cycle 20 can be performed by the ON period.

  The cycle PT of the first control timer HTM1 is the same as the cycle PT of the second control timer HTM2. However, the waveform of the first control timer HTM1 is different from the waveform of the second control timer HTM2. The waveform of the first control timer HTM1 and the waveform of the second control timer HTM2 are shifted by PT / 2. The first period PD1 and the second period PD2 are shifted so as not to occur simultaneously, that is, not to overlap. An invalid period TD is provided between the first period PD1 and the second period PD2. In the invalid period TD, the defrosting operation is not permitted. The invalid period TD is used to execute the heating operation by all the cycles between the defrosting operation for one cycle and the defrosting operation for the other one cycle.

  The control measure 6 includes a schedule unit. The schedule unit is provided by step 161 and control timers HTM1 and HTM2 provided thereby. The schedule unit sequentially sets the defrosting operation permission periods PD1 and PD2 for the plurality of cycles 10 and 20 without overlapping each other. The schedule unit alternately gives the defrosting operation permission period PD1 for the first cycle 10 and the defrosting operation permission period PD2 for the second cycle 20. The control timers HTM1 and HTM2 set the permission periods PD1 and PD2 repeatedly at a predetermined period PT.

  FIG. 8 shows an operation process 170 for the vehicle air conditioner 1 that is executed in response to the frosting determination processes 140 and 150. In the figure, the operation processing for the cycles 10 and 20 is mainly shown.

  In step 171, the control device 6 determines whether or not a defrost timer DTM, which will be described later, exceeds a predetermined threshold time Dth. If DTM> Dth, the process proceeds to step 176. This process prevents the defrosting operation for a long time exceeding the threshold time Dth.

  In step 172, the control device 6 determines whether or not the first control timer HTM1 is ON. In step 173, the control device 6 determines whether or not the second control timer HTM2 is ON. If it is determined in step 172 that the first control timer HTM1 is ON, the process proceeds to step 174. If the second control timer HTM2 is ON in step 173, the process proceeds to step 175. If both control timers HTM1, HTM2 are OFF, the process proceeds to step 176.

  In step 176, the control device 6 executes normal heating control. The control device 6 controls the four-way valves 17 and 27 and the like so that the first cycle 10 executes the heating operation and at the same time the second cycle 20 executes the heating operation. As a result, the room is heated by both cycles 10 and 20. Step 176 provides a heating process 177 in which both cycles 10 and 20 are heated. The heating process 177 provides a heat pump operation unit that simultaneously performs a heat pump operation by a plurality of cycles 10 and 20. The control device 6 includes a heat pump operation unit.

  In step 174, the control device 6 determines whether or not the flag FLG1 for requesting defrosting for the first cycle 10 is set. When the flag FLG1 is set, the control device 6 executes the defrost heating process 180 for the first cycle 10. When the flag FLG1 is not set, the control device 6 executes the heating process 177. Therefore, when the defrosting operation for the first cycle 10 is permitted by the control timer HTM1 and the defrosting for the first cycle 10 is requested, the control device 6 performs the defrosting heating process 180. Run.

  The defrost heating processing 180 provides a first defrosting operation unit that executes the defrosting operation of one cycle 10 in response to the schedule unit HTM1 and simultaneously executes the heat pump operation of the other one cycle 20. . The control device 6 includes a first defrosting operation unit.

  In step 181, the control device 6 starts time measurement by the defrost timer DTM. The defrost timer DTM defines the maximum duration of the defrost operation. In step 182, the control device 6 executes the defrost heating operation for the first cycle 10. The control device 6 controls the four-way valves 17 and 27 and the like so that the first cycle 10 performs the defrosting operation and at the same time the second cycle 20 performs the heating operation. As a result, the room is heated by the second cycle 20 while defrosting the first cycle 10.

  Steps 183 to 185 provide an end determination process that defines the end of the defrost heating process 180. If the end is not detected in any of steps 183-185, the process returns to step 182.

  In step 183, the control device 6 determines whether or not the control timer HTM1 is ON. When the control timer HTM1 is OFF, it indicates that the first period PD1 has ended. The period during which the control timer HTM1 is OFF is a period during which the defrosting operation for the first cycle 10 is prohibited. If the control timer HTM1 is turned OFF during the defrost heating process 180, the process proceeds to step 186 to end the defrost heating process 180. In other words, the control device 6 ends the defrosting operation in response to the end of the first period PD1.

  In step 184, the control device 6 determines whether or not the detected temperature FR1 exceeds the threshold temperature Tth. In the case of FR1> Tth, the outdoor heat exchanger 12 is considered to be sufficiently high in temperature so that the defrosting operation is unnecessary. Step 184 avoids excessive temperature rise. The threshold temperature Tth is a threshold value for ending the defrosting operation. The threshold temperature Tth in step 184 can be set to a temperature higher than the threshold temperature Tth in steps 141 and 143. If FR1> Tth during the defrost heating process 180, the process proceeds to step 186 to end the defrost heating process 180. In other words, the control device 6 ends the defrosting operation in response to the outdoor heat exchanger 12 being sufficiently heated.

  In step 185, the control device 6 determines whether or not the defrost timer DTM exceeds the threshold time Dth. The threshold time Dth defines the maximum duration of the defrosting operation. If DTM> Dth during the defrost heating process 180, the process proceeds to step 186 to end the defrost heating process 180. In other words, the control device 6 terminates the defrosting operation in response to the continuation time of the defrosting operation reaching a predetermined value.

  In step 186, the control device 6 executes a termination process for terminating the defrosting heating operation. The termination process can include a process of switching the first cycle 10 that has been defrosted to a state for heating operation, and a standby process until the refrigerant pressure is balanced. After the defrosting operation is completed, the control device 6 always executes step 176. When the defrosting operation is completed in step 183, the processing flow proceeds from step 173 to step 176. When the defrosting operation is completed in step 184, the flag FLG1 is reset by the process 140, and the process flow advances from step 174 to step 176. When the defrosting operation is completed in step 185, the process flow proceeds from step 171 to step 176.

  In step 175, the control device 6 determines whether or not the flag FLG2 for requesting defrosting for the second cycle 20 is set. When the flag FLG2 is set, the control device 6 executes the defrost heating process 190 for the second cycle 20. When the flag FLG2 is not set, the control device 6 executes the heating process 177. Therefore, when the defrosting operation for the second cycle 20 is permitted by the control timer HTM2 and the defrosting for the second cycle 20 is requested by the control timer HTM2, the control device 6 performs the defrosting heating process 190. Run.

  In step 191, the control device 6 starts time measurement by the defrost timer DTM. In step 192, the control device 6 executes the defrost heating operation for the second cycle 20. The control device 6 controls the four-way valves 17 and 27 and the like so that the second cycle 20 performs the defrosting operation and at the same time the first cycle 10 performs the heating operation. As a result, the room is heated by the first cycle 10 while defrosting the second cycle 20.

  Steps 193 to 195 provide an end determination process that defines the end of the defrost heating process 190. Steps 193-195 and 196 correspond to Steps 183-185 and 186. In Steps 193 to 196, the control device 6 executes the same processing as that in Steps 183 to 186 for the second cycle 20.

  The defrosting heating process 190 provides a second defrosting operation unit that executes the defrosting operation of one cycle 20 in response to the schedule unit HTM2 and simultaneously executes the heat pump operation of the other one cycle 10. . The control device 6 includes a second defrosting operation unit.

  4 and FIG. 5, the control device 6 independently determines whether or not the defrosting in the first cycle 10 is necessary and whether or not the defrosting is necessary in the second cycle 20. To do. The frosting determination processes 140 and 150 provide a determination unit that determines whether or not a defrosting operation is necessary for each of a plurality of cycles. Therefore, the control device 6 includes determination units 140 and 150.

  Furthermore, by the operation process 170 shown in FIG. 8, the control device 6 selects and executes the heating operation or the defrosting operation. When defrosting is not required in the frosting determination processes 140 and 150, the control device 6 performs the heating operation by both cycles 10 and 20.

  When defrosting of only the first cycle 10 is requested in the frosting determination processes 140 and 150, the control device 6 executes the defrosting operation for the first cycle 10, and at the same time, for the second cycle 20 Perform heating operation. Moreover, the control device 6 performs the defrosting operation for the first cycle 10 only during the period when the defrosting operation of the first cycle 10 is permitted by the control timers HTM1 and HTM2.

  When defrosting of only the second cycle 20 is requested in the frosting determination processes 140 and 150, the control device 6 executes the defrosting operation for the second cycle 20, and at the same time, for the first cycle 10. Perform heating operation. In addition, the control device 6 executes the defrosting operation for the second cycle 20 only during the period when the defrosting operation of the second cycle 20 is permitted by the control timers HTM1 and HTM2.

  The defrosting operation units 180 and 190 perform one cycle of defrosting when the defrosting operation is permitted by the permission periods PD1 and PD2 given from the schedule unit and the necessity of the defrosting operation is determined by the determination unit. Execute the operation, and at the same time execute another one cycle heat pump operation. According to this configuration, when the necessity of the defrosting operation of one cycle is determined and the opportunity of the defrosting operation of the one cycle is given, the defrosting operation of the one cycle is executed. The Therefore, it is possible to avoid the simultaneous defrosting operation of a plurality of cycles while responding to the necessity for the defrosting operation.

  The control timers HTM1 and HTM2 are set so as not to permit the defrosting operation of the first cycle 10 and the defrosting operation of the second cycle 20 at the same time. Therefore, even if both the defrosting of the 1st cycle 10 and the defrosting of the 2nd cycle 20 are requested | required, it is avoided that both the cycles 10 and 20 perform a defrosting operation simultaneously.

  Further, the control timers HTM1 and HTM2 are set so that both the cycles 10 and 20 simultaneously execute the heating operation both before and after the defrosting operation for one cycle. In other words, the schedule unit sets a period TD during which the heat pump operation of the plurality of cycles 10 and 20 is executed by the heat pump operation unit between the permission period PD1 and the permission period PD2. According to this configuration, the heat pump operation is executed between the defrosting operation and the defrosting operation. Therefore, the continuous shortage over the long term of the heating capability resulting from a defrost operation is suppressed.

  FIG. 9 shows an example of the operation when the vehicle air conditioner 1 heats up. The signal PWSW is a signal for instructing heating. The signal PWSW is given by, for example, a switch operated by a vehicle driver. At time t0, the signal PWSW is turned on. Heating is provided during periods when the signal PWSW is ON. When the signal PWSW is turned off at time te, the heating ends.

As shown between the time t0 and the time t1, the vehicle air conditioner 1 provides a plurality of different operation modes depending on the heating load. The vehicle air conditioner 1 provides a plurality of operation modes by switching the heating capacity of each of the plurality of cycles 10 and 20 to low capacity L, high capacity H, or stop OFF. The vehicle air conditioner 1 provides a mode in which the first cycle 10 is operated at a low capacity L and the second cycle 20 is operated at a low capacity L. The vehicle air conditioner 1 provides a mode in which the first cycle 10 is operated at a high capacity H and the second cycle 20 is operated at a low capacity L. The vehicle air conditioner 1 provides a mode in which the first cycle 10 is operated at a high capacity H and the second cycle 20 is operated at a high capacity H. The vehicle air conditioner 1 provides a mode in which the first cycle 10 is operated at a low capacity L and the second cycle 20 is operated at a high capacity H.
The vehicle air conditioner 1 provides a mode in which the first cycle 10 is stopped OFF and the second cycle 20 is operated at a low capacity L. The vehicle air conditioner 1 provides a mode in which the first cycle 10 is operated at a low capacity L and the second cycle 20 is stopped OFF.

  The vehicle air conditioner 1 adjusts the heating capacity stepwise or continuously between the stop OFF and the high capacity H by variably controlling the rotation speeds of the compressors 13, 14, 23, and 24. Can do.

  In the figure, an example of the defrosting operation is shown after time t10. In the figure, DEF indicates a defrosting operation. At time t11, the control timer HTM1 is turned on. At this time, the flag FLG1 is ON. Control device 6 starts the defrosting operation for first cycle 10 in response to control timer HTM1 and flag FLG1. When the defrosting of the outdoor heat exchanger 12 proceeds, the temperature of the outdoor heat exchanger 12 rises. At time t12, the detected temperature FR1 exceeds the threshold temperature Tth. As a result, the control device 6 ends the defrosting operation. At the same time, the control device 6 resets the flag FLG1 to OFF.

  While performing the defrosting operation for the first cycle 10 between the time t11 and the time t12, the control device 6 executes the heating operation for the second cycle 20. After the time t12, the control device 6 performs the heating operation according to both the cycles 10 and 20.

  Next, the flag FLG2 is turned ON at time t13. At this time, the control timer HTM2 is ON. Control device 6 starts the defrosting operation for second cycle 20 in response to control timer HTM2 and flag FLG2. At time t14, the control timer HTM2 is turned off. The control device 6 ends the defrosting operation of the second cycle 20 in response to the control timer HTM2.

  While the defrosting operation for the second cycle 20 is executed between the time t13 and the time t14, the control device 6 executes the heating operation for the first cycle 10. After the time t14, the control device 6 performs the heating operation according to both the cycles 10 and 20.

  Next, at time t15, the flag FLG1 is turned ON. At this time, the control timer HTM1 is ON. Control device 6 starts the defrosting operation for first cycle 10 in response to control timer HTM1 and flag FLG1. At time t15, the flag FLG2 is also ON. However, the control timer HTM2 is OFF. Therefore, the defrosting operation of the second cycle 20 is not executed. At time t16, the control timer HTM1 is turned off. The control device 6 ends the defrosting operation for the first cycle 10 in response to the control timer HTM1.

  While the defrosting operation for the first cycle 10 is executed between the time t15 and the time t16, the control device 6 executes the heating operation for the second cycle 20. After time t16, the control device 6 executes the heating operation according to both the cycles 10 and 20.

  At time t17, the control timer HTM2 is turned on. At this time, the flag FLG2 is ON. Control device 6 starts the defrosting operation for second cycle 20 in response to control timer HTM2 and flag FLG2. When the defrosting of the outdoor heat exchanger 22 proceeds, the temperature of the outdoor heat exchanger 22 increases. At time t18, the detected temperature FR2 exceeds the threshold temperature Tth. As a result, the control device 6 ends the defrosting operation. At the same time, the control device 6 resets the flag FLG2 to OFF.

  While performing the defrosting operation for the second cycle 20 between the time t17 and the time t18, the control device 6 performs the heating operation for the first cycle 10. After the time t18, the control device 6 performs the heating operation according to both the cycles 10 and 20.

  As illustrated, the control timers HTM1 and HTM2 allow the defrosting operation for each cycle to be executed sequentially, for example, alternately without overlapping each other. Moreover, when the defrosting operation for one cycle is executed, the other one cycle performs the heating operation. Therefore, the fall of the heating capability resulting from a defrost operation is suppressed.

  Moreover, the plurality of cycles 10 and 20 simultaneously perform the heating operation both before the defrosting operation and after the defrosting operation. For this reason, the excessive fall of the indoor heating effect can be suppressed.

  Furthermore, even if the defrosting operation of the plurality of cycles 10 and 20 is continuously requested, the defrosting operation for one cycle and the defrosting operation for the other one cycle are executed alternately. . For this reason, the amount of frost formation of several cycles 10 and 20 is averaged. Further, the heating capacity of the plurality of cycles 10 and 20 is averaged. Furthermore, the cumulative operating time of the plurality of cycles 10, 20 is averaged.

  Further, the plurality of cycles 10 and 20 constitute a multistage compression type cycle when the heating operation is executed. For this reason, a high heating capability can be provided. In particular, heating can be provided even when the outside air temperature is extremely low. High heating capacity is also provided when only one cycle is in heating operation. The plurality of cycles 10 and 20 constitute a single-stage compression type cycle when performing the defrosting operation. For this reason, the excessive raise of the temperature of the outdoor heat exchangers 12 and 22 and the local raise are suppressed. As a result, for example, provision of an appropriate defrosting capability in the vicinity of 0 ° C where frost easily adheres can be realized.

(Second Embodiment)
In the above embodiment, when one cycle performs the defrosting operation, the other one cycle performs the heating operation. In this embodiment, in order to suppress a decrease in the heating capacity due to the defrosting operation of one cycle, the heating operation in which the other one cycle is strengthened is executed.

  In FIG. 10, in this embodiment, the control device 6 executes an operation process 270 instead of the operation process 170 of the preceding embodiment. Instead of steps 182 and 192 of the preceding embodiment, steps 282 and 292 are employed.

  In step 282, the control device 6 performs defrost heating. Here, the heating capacity of the second cycle 20 in which the heating operation is performed is enhanced. Here, the control apparatus 6 increases heating capacity by setting the rotation speed of the compressors 23 and 24 to the maximum value.

  Furthermore, in step 282, the control device 6 performs a delay process so that the heating operation enhanced by the second cycle 20 is performed over a longer period including the period in which the first cycle 10 performs the defrosting operation. . The control device 6 starts the defrosting operation for the first cycle 10 when a predetermined delay time TL has elapsed since the heating operation enhanced by the second cycle 20 was started. Further, the control device 6 ends the enhanced heating operation by the second cycle 20 when a predetermined delay time TT has elapsed since the completion of the defrosting operation for the first cycle 10.

  In step 292, the control apparatus 6 performs defrost heating. Here, the heating capacity of the first cycle 10 in which the heating operation is performed is enhanced. Here, the control device 6 increases the heating capacity by setting the rotation speed of the compressors 13 and 14 to the maximum value.

  Furthermore, in step 292, the control device 6 executes a delay process so that the heating operation enhanced by the first cycle 10 is performed over a longer period including the period in which the second cycle 20 performs the defrosting operation. . The control device 6 starts the defrosting operation for the second cycle 20 when a predetermined delay time TL has elapsed since the heating operation enhanced by the first cycle 10 was started. In addition, the control device 6 ends the enhanced heating operation according to the first cycle 10 when a predetermined delay time TT has elapsed since the end of the defrosting operation for the second cycle 20.

  According to this embodiment, as illustrated in FIG. 11, the defrosting operation and the enhanced heating are performed simultaneously, and the enhanced heating is performed over a period longer than the defrosting period. In the illustrated example, in the second cycle 20, the enhanced heating operation is performed from time t21 to time t24. In the first cycle 10, the defrosting operation is performed from time t22 to time t23. Reinforced heating is performed over a longer period than the defrosting operation. Moreover, the reinforced heating is performed over both the period TL before the defrosting operation and the subsequent period TT.

  According to this embodiment, the same advantages as the preceding embodiments are obtained. Moreover, according to this embodiment, when executing the defrosting operation of one cycle, the control device 6 executes the enhanced heat pump operation of the other one cycle at the same time. Therefore, the fall of the heating capability resulting from a defrost operation can be suppressed more reliably. In addition, the control device 6 performs the enhanced heat pump operation of the other one cycle over a longer period including the period of performing the defrosting operation of one cycle. Therefore, it is possible to more reliably suppress a decrease in heating capacity.

(Third embodiment)
In the said embodiment, the defrost operation was provided by reversing the flow of the refrigerant | coolant in a cycle. In this embodiment, a defrosting operation is provided by supplying a high-temperature refrigerant to the outdoor heat exchangers 12 and 22.

  In FIG. 12, cycles 10 and 20 include hot gas bypass passages 319 a and 329 b that introduce high-temperature and high-pressure refrigerant from the compressors 14 and 24 directly into the outdoor heat exchangers 12 and 22. On-off valves 319b and 329b are provided in the hot gas bypass passages 319a and 319b. The on-off valves 319b and 329b are closed during the heating operation. The on-off valves 319b and 329b are opened during the defrosting operation. By opening the on-off valves 319b and 329b, high-temperature refrigerant is introduced into the outdoor heat exchangers 12 and 22, and defrosting is performed.

  According to this embodiment, the heating operation and the defrosting operation can be switched without reversing the flow direction of the refrigerant in the cycles 10 and 20.

(Other embodiments)
The preferred embodiments of the disclosed invention have been described above, but the disclosed invention is not limited to the above-described embodiments, and various modifications can be made. The structure of the said embodiment is an illustration to the last, Comprising: The technical scope of the disclosed invention is not limited to the range of these description. The technical scope of the disclosed invention is indicated by the description of the scope of claims, and further includes all modifications within the meaning and scope equivalent to the description of the scope of claims.

  For example, the means and functions provided by the control device can be provided by software only, hardware only, or a combination thereof. For example, the control device may be configured by an analog circuit.

  In the above embodiment, an example in which the disclosed invention is applied to an air conditioner has been described. Instead, the disclosed invention can be applied to heat pump devices such as residential air conditioners, building air conditioners, and hot water supply devices. Further, the heat pump operation called the heating operation may be called a boiling operation or a hot water supply operation. The disclosed invention can be applied not only to a heat pump apparatus using air as a heat source but also to a heat pump apparatus using water, geothermal heat, or the like as a heat source. The disclosed invention can also be applied to a heat pump apparatus including three or more cycles.

  Moreover, in the said embodiment, in order to give the opportunity of a defrost operation to all the cycles 10 and 20 in order, control timer HTM1 and HTM2 were employ | adopted. Instead, during the predetermined prohibition period after the defrosting operation for one cycle is executed, the defrosting operation for the same cycle is prohibited and only the defrosting operation for the other cycle is performed. You may provide the prohibition process part which permits.

  In the above embodiment, the control timers HTM1 and HTM2 are provided by software processing by the control device 6. Alternatively, various devices that provide two complementary outputs can be utilized. For example, a PWM oscillation circuit having a complementary output, a multivibrator circuit, or the like can be used.

  Moreover, in the said embodiment, in order to provide enhanced heating, the rotation speed of the compressor was controlled to the maximum value. Instead of this, the rotational speed of the compressor may be controlled to a rotational speed obtained by adding a predetermined added value. For example, the compressor may be operated at a rotational speed obtained by adding a predetermined added value to the rotational speed given by feedback control for heating operation.

1 vehicle air conditioner, 2 air conditioning unit,
4a blower, 5a blower,
4b blower, 5b blower,
6 control device, 7 frost sensor, 8 frost sensor,
10 first cycle, 11 indoor heat exchanger, 12 outdoor heat exchanger,
13 First stage compressor, 14 Second stage compressor,
15 pressure reducer, 16 accumulator, 17 four-way valve, 18 on-off valve,
20 second cycle, 21 indoor heat exchanger, 22 outdoor heat exchanger,
23 First stage compressor, 24 Second stage compressor,
25 pressure reducer, 26 accumulator, 27 four-way valve, 28 on-off valve.

Claims (9)

A plurality of cycles (10, 20) each including a front stage compressor (13, 23) and a rear stage compressor (14, 24) capable of being operated as a multistage compression type cycle and functioning as a heat pump;
A control device (6) for switching each operation mode of the plurality of cycles to a heat pump operation and a defrosting operation;
The control device (6)
A schedule unit (161, HTM1, HTM2) for sequentially setting the permission periods (PD1, PD2) of the defrosting operation for the plurality of cycles (10, 20) without overlapping each other;
A heat pump operation section (176) for simultaneously executing a heat pump operation by a plurality of the cycles;
In response to the schedule unit, the defrosting operation of one cycle is executed, and at the same time, the defrosting operation unit (180, 190) that executes the heat pump operation of the other one cycle,
A plurality of the cycles (10, 20) are operated as the multistage compression cycle when the heat pump operation is executed. The plurality of cycles (10, 20) includes a first cycle (10) and a second cycle (20),
The defrosting operation unit (180, 190)
In response to the schedule unit, the first cycle defrosting operation is performed, and at the same time, the second cycle heat pump operation is performed, and a first defrosting operation unit (180),
A second defrosting operation unit (190) for executing the defrosting operation of the second cycle in response to the schedule unit and simultaneously executing the heat pump operation of the first cycle;
The schedule unit alternately gives a defrosting operation permission period (PD1) for the first cycle and a defrosting operation permission period (PD2) for the second cycle. The heat pump apparatus according to 1.   The schedule unit includes a plurality of defrosting operation permission periods (PD1) for the first cycle and a defrosting operation permission period (PD2) for the second cycle. The heat pump apparatus according to claim 2, wherein a period (TD) in which the heat pump operation of the cycle is executed is set.   The said schedule part is provided with the timer (HTM1, HTM2) which repeats and sets the said permission period (PD1, PD2) with a predetermined period (PT), The Claim 1 characterized by the above-mentioned. Heat pump device. The control device (6) further comprises:
A determination unit (140, 150) for determining whether or not a defrosting operation is required for each of the plurality of cycles;
The defrosting operation unit (180, 190) is permitted when the defrosting operation is permitted by the permission period given from the schedule unit, and the necessity of the defrosting operation is determined by the determination unit. The heat pump device according to any one of claims 1 to 4, wherein a defrosting operation of a cycle is executed and at the same time a heat pump operation of another one of the cycles is executed.   The heat pump device according to any one of claims 1 to 5, wherein the plurality of cycles (10, 20) are operated as a single-stage compression type cycle when the defrosting operation is performed. .   The defrosting operation unit (180, 190), when performing the defrosting operation of one of the cycles, simultaneously executes the enhanced heat pump operation of the other one of the cycles. The heat pump device according to claim 6.   The defrosting operation unit (180, 190) performs an enhanced heat pump operation of another one of the cycles over a longer period including a period of performing the defrosting operation of one of the cycles. The heat pump device according to claim 7.   The heat pump device according to any one of claims 1 to 8, wherein the plurality of cycles are heating cycles for heating the interior of the vehicle using air outside the vehicle as a heat source.

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