JP3735338B2 - Refrigeration apparatus for vehicle and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration apparatus for a refrigeration vehicle that can perform not only cold insulation but also heat insulation, and a control method thereof, and relates to a technique for quickly and efficiently heating the inside of a refrigerator in a heat insulation state.
[0002]
[Prior art]
There are the following two methods for heating for keeping warm in a refrigerator that can keep warm as well as cold.
(1) Hot water heating method
Cooling water for a vehicle engine (although its temperature is around 90 ° C.) is introduced into the cabinet and the interior is heated by radiating heat (for example, Patent Document 1 below).
(2) Hot gas refrigerant heating method
The refrigerant discharged from the compressor (high-temperature and high-pressure gas-phase state) is directly introduced into the evaporator, and the interior is heated by radiating heat in the evaporator.
[0003]
[Patent Document 1]
JP-A-10-160321 (paragraph [0016], FIG. 4)
[0004]
[Problems to be solved by the invention]
By the way, the following problems have been pointed out in the above two heating methods.
First, in the warm water heating method of (1), it is necessary to separately construct a pipe for introducing cooling water into the warehouse, and the mounting of the refrigeration apparatus on the vehicle becomes complicated.
In the hot gas refrigerant heating method (2), since the refrigerant radiated in the evaporator (cooled to the air in the warehouse) becomes a gas-liquid two-phase state at the evaporator outlet, the refrigerant in the liquid phase state is supplied to the compressor. It is necessary to keep the liquid refrigerant in the accumulator so that it does not suck and break. If it carries out like this, the refrigerant | coolant amount which functions substantially in the system which forms a refrigerating cycle will reduce, and performance will fall. Furthermore, if the liquid refrigerant accumulates too much in the accumulator, a phenomenon such as liquid return or oil (lubricating oil) dilution may occur, causing problems. Further, when shifting from the heating operation to the cooling operation, it is necessary to move the liquid refrigerant from the accumulator to the condenser / receiver, and it is impossible to overlook the point that the loss during the transition period is large.
[0005]
This invention is made | formed in view of said situation, and it aims at heating the inside in the heat retention state rapidly and efficiently.
[0006]
[Means for Solving the Problems]
  As means for solving the above problems, a vehicular refrigeration apparatus having the following configuration and a control method thereof are adopted.
  That is, the refrigeration apparatus for a vehicle according to claim 1 according to the present invention includes:A vehicular refrigeration apparatus in which a refrigeration cycle is configured by connecting a compressor, a condenser, a receiver, an expansion valve, and an evaporator with a refrigerant pipe, and the refrigerant in a gas phase discharged from the compressor is supplied to the condenser and the expansion valve. Bypass passage to be introduced into the evaporator, decompression means for depressurizing the refrigerant flowing through the bypass passage to a temperature equal to or lower than the internal temperature saturation pressure of the heat retaining cabinet, and opening and closing the bypass passage to interrupt the circulation of the refrigerant And opening / closing means for performing heat dissipation, and when the refrigerant that has become a low-temperature and low-pressure gas phase by radiating heat from the evaporator is lower than a predetermined pressure, a part of the liquid-phase refrigerant held in the receiver is Provided refrigerant discharge low pressure control means to add to the refrigerantIt is characterized by that.
[0008]
  In the present invention, when the refrigerant in the gas phase state is reduced to a temperature equal to or lower than the internal temperature saturation pressure of the heat insulation chamber and then introduced into the evaporator, the introduced refrigerant is condensed in the evaporator.WithoutTo dissipate heat. Thereby, the heating operation can be performed without separately constructing a pipe for introducing the cooling water into the cabinet as in the conventional warm water cooling system. In addition, the system that realizes the refrigeration cycle is in a single-phase state of superheated gas, and there is no need to keep the liquid refrigerant in the accumulator as in the conventional hot gas refrigerant heating method, so that the amount of refrigerant that functions substantially is sufficient. Secured. Furthermore, since liquid refrigerant is not stored in the accumulator, phenomena such as liquid return and oil dilution do not occur. In addition, when shifting from the heating operation to the cooling operation, the amount of refrigerant in the accumulator is small, so that the loss during the transition period can be small.
  For example, if the outside air temperature becomes very low, refrigerant may accumulate in the condenser or receiver, and the amount of refrigerant circulating in the system may be insufficient.Therefore, the pressure of the refrigerant to be sucked into the compressor, that is, the refrigerant pressure on the low pressure side will also be Along with this, it decreases. Therefore, in the present invention, the refrigerant pressure on the low pressure side is maintained at a predetermined pressure by adding a part of the refrigerant in the vapor phase state held by the receiver to the refrigerant in the system.
[0009]
  Claim2The vehicle refrigeration apparatus according to claim 2, wherein, in the vehicle refrigeration apparatus, when a gas-phase refrigerant discharged from the compressor is higher than a predetermined pressure, a part of the gas-phase refrigerant is removed. High voltage control means for introducing the capacitor is provided.
[0010]
As described above, if the refrigerant dissipates heat in the evaporator without condensing, the system that realizes the refrigeration cycle becomes a single phase of superheated gas, so the discharge pressure of the compressor is determined by the amount of refrigerant circulating in the system Is done. However, if the amount of refrigerant held in the accumulator or receiver changes, the discharge pressure of the compressor, that is, the high-pressure side refrigerant pressure also changes accordingly. Therefore, in the present invention, the refrigerant pressure on the high pressure side is maintained at a predetermined pressure by introducing a part of the refrigerant in the gas phase discharged from the compressor into the condenser.
[0011]
The vehicle refrigeration apparatus according to claim 4 is the vehicle refrigeration apparatus according to claim 2 or 3, wherein the refrigerant that has dissipated heat in the evaporator and is in a low-temperature and low-pressure gas phase state is lower than a predetermined pressure, A refrigerant discharge low-pressure control means for adding a part of the gas-phase refrigerant held by the receiver to the refrigerant is provided.
[0012]
For example, if the outside air temperature becomes very low, refrigerant may accumulate in the condenser or receiver, and the amount of refrigerant circulating in the system may be insufficient.Therefore, the pressure of the refrigerant to be sucked into the compressor, that is, the refrigerant pressure on the low pressure side will also be Along with this, it decreases. Therefore, in the present invention, the refrigerant pressure on the low pressure side is maintained at a predetermined pressure by adding a part of the refrigerant in the vapor phase state held by the receiver to the refrigerant in the system.
[0013]
  Claim3The vehicle refrigeration apparatus according to claim 4, wherein, in the vehicle refrigeration apparatus, when the refrigerant that has dissipated heat in the evaporator and is in a low-temperature and low-pressure gas-phase state is lower than a predetermined pressure, the refrigerant is held by the receiver. A refrigerant introduction low-pressure control means is provided for introducing a refrigerant discharged from the compressor into the receiver so as to add a part of the liquid phase refrigerant to the refrigerant.
[0014]
In the present invention, the refrigerant pressure on the low pressure side is kept at a predetermined pressure by introducing into the receiver the refrigerant discharged from the compressor in order to add a part of the liquid phase refrigerant held in the receiver to the refrigerant. It is.
[0015]
  The vehicle refrigeration apparatus according to claim 6 includes a compressor, a condenser,Receiver,And a vehicular refrigeration apparatus including two evaporators connected in parallel to a system realizing a refrigeration cycle together with an expansion valve and distributed to two cold storage cabinets,
  The refrigerant in the gas phase discharged from the compressor is reduced in pressure by the pressure reducing means to the temperature equal to or lower than the internal temperature saturation pressure of the cold storage without passing through the condenser and the expansion valve, and then introduced into one evaporator. Heating operation to heat the cold storage of
  A cooling operation for cooling the other cold storage by allowing the refrigerant in the gas phase state discharged from the compressor to be placed in the other evaporator on the refrigeration cycle is possible,
  A control unit that alternately performs the heating operation or the cooling operation,
  The control unit is configured to add a part of the liquid-phase refrigerant held by the receiver to the refrigerant when the refrigerant in a low-temperature and low-pressure gas-phase state is radiated by the evaporator and lower than a predetermined pressure. Has low pressure control meansIt is characterized by that.
[0016]
  The vehicle refrigeration apparatus control method according to claim 5 includes a compressor, a condenser,Receiver,And a control method of a vehicle refrigeration apparatus including two evaporators connected in parallel to a system realizing a refrigeration cycle together with an expansion valve and distributed to two cold storage cabinets,
  The refrigerant in the gas phase discharged from the compressor is reduced in pressure by the pressure reducing means to the temperature equal to or lower than the internal temperature saturation pressure of the cold storage without passing through the condenser and the expansion valve, and then introduced into one evaporator. Heating operation to heat the cold storage of
  A cooling operation for cooling the other cold storage by allowing the refrigerant in the gas phase state discharged from the compressor to be placed in the other evaporator on the refrigeration cycle is possible,
  While alternately performing the heating operation or the cooling operation,When the refrigerant that has dissipated heat in the evaporator and is in a low-temperature and low-pressure gas-phase state is lower than a predetermined pressure, a part of the liquid-phase refrigerant held in the receiver is added to the refrigerant to set the pressure. Control moreIt is characterized by that.
[0017]
In the present invention, by alternately performing the heating operation and the normal cooling operation as described above, the operation of one-chamber heating and one-chamber cooling can be performed quickly and efficiently.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 shows an outline of a vehicle refrigeration apparatus mounted on a refrigeration vehicle having two cold storage boxes (however, not only cold storage but also heat insulation can be performed). In the figure, reference numeral 1 is a compressor, 2 is a condenser, 3A and 3B are expansion valves, 4A and 4B are evaporators, 5 is an accumulator, and 6 is a receiver. Each device is connected via a refrigerant pipe L1 indicated by a thick solid line in the drawing to constitute a system that realizes a refrigeration cycle. Further, reference numeral 7 in the figure is a control unit, 8 is an input unit, and 9 is a storage unit.
[0019]
The two evaporators 4A and 4B are connected in parallel to the system together with the expansion valves 3A and 3B. One pipe in which the expansion valve 3A and the evaporator 4A are branched in parallel is provided with an on-off valve 10A for intermittently introducing refrigerant into the evaporator 4A, and one pipe in which the expansion valve 3B and the evaporator 4B are arranged. Is provided with an on-off valve 10B for intermittently introducing the refrigerant into the evaporator 4B. The evaporator 4A is disposed in one of the two coolers (hereinafter referred to as the front chamber A), and the evaporator 4B is disposed in the other of the two coolers (hereinafter referred to as the rear chamber B).
[0020]
The main refrigerant pipe L1 includes a bypass pipe (bypass path; a thin solid line in the figure) for introducing the refrigerant discharged from the compressor 1 to the evaporators 4A and 4B, bypassing the condenser 2, the receiver 6, and the expansion valves 3A and 3B. L2) is connected. The tip of the bypass pipe L2 branches into two, one of which is connected to the inlet side of the evaporator 4A and the other is connected to the inlet side of the evaporator 4B. One bypass pipe connected to the inlet side of the evaporator 4A is provided with an opening / closing valve (opening / closing means) 10C for intermittently introducing the refrigerant into the evaporator 4A, and the other bypass pipe connected to the inlet side of the evaporator 4B. The bypass pipe is provided with an open / close valve (open / close means) 10D for intermittently introducing the refrigerant into the evaporator 4B.
[0021]
In the bypass pipe L2, a refrigerant in a gas phase state is set to a predetermined pressure (low pressure; PLset, a temperature equal to or lower than the internal temperature saturation pressure of the cool box placed in an overheated state, and takes a specific value. A constant pressure expansion valve (decompression unit) 11 that depressurizes to the following level may be provided. The bypass pipe L2 is provided with a bypass pipe L3 that bypasses the constant pressure expansion valve 11. The bypass pipe L3 is provided with an on-off valve 12 that intermittently connects the pipe line.
[0022]
On the high pressure side of the refrigerant pipe L1 (between the compressor 1 and the condenser 2), a discharge pressure adjusting valve that opens when the discharge pressure of the compressor 1 becomes equal to or higher than a predetermined pressure (high pressure; higher than PHset, PLset). (High pressure control means) 13 is provided.
[0023]
Between the receiver 6 and the refrigerant | coolant piping L1, the liquid phase component of the refrigerant | coolants hold | maintained inside the receiver 6 is supplied to the low voltage | pressure side (between evaporator 4A, 4B and the compressor 1) of the refrigerant | coolant piping L1. A liquid return pipe L4 is connected. The liquid return pipe L4 is provided with an on-off valve 14 for intermittently circulating the liquid refrigerant in the pipe (the liquid return pipe L4 and the on-off valve 14 use the pressure of the refrigerant remaining in the receiver 6). And a refrigerant discharge low-pressure control means for increasing the pressure on the refrigerant pipe L1 side which is the low-pressure side).
[0024]
Further, a further low pressure control means is provided in case the pressure rise is insufficient with the refrigerant discharge low pressure control means described above. Specifically, as shown in FIG. 1, high-pressure discharge refrigerant is introduced into the receiver 6 between the receiver 6 and the bypass pipe L2, and refrigerant remaining in the receiver 6 is led out to the refrigerant pipe L1 side. A gas return pipe L5 for connecting is connected. The gas return pipe L5 is provided with an on-off valve 15 for intermittently circulating the gas-phase refrigerant in the pipe (the gas return pipe L5 and the on-off valve 15 are combined with the refrigerant discharge low-pressure control means described above. The refrigerant is introduced into the receiver 6 and serves as refrigerant introduction low-pressure control means for increasing the pressure of the refrigerant pipe L1 which is the low-pressure side).
[0025]
A check valve 16 that restricts the flow of refrigerant in one direction is installed between the compressor 1 and the condenser 2, between the condenser 2 and the receiver 6, and in the refrigerant pipe L1 on the outlet side of the evaporators 4A and 4B. Has been. Also, room temperature sensors 17A and 17B are installed in the front chamber A and the rear chamber B, respectively, and a pressure sensor 18 is installed on the low pressure side of the refrigerant pipe L1.
[0026]
The control unit 7 is connected to the on-off valves 10A to 10D, 12, 14, and 15, the room temperature sensors 17A and 17B, and the pressure sensor 18 through signal wirings indicated by broken lines in the drawing, and the room temperature sensors 17A and 17B, the pressure sensor Based on the 18 measurement results and the set temperatures of the front chamber A and the rear chamber B, the driving of the on-off valves 10A to 10D, 12, 14, and 15 is controlled. The input unit 8 is used to input information such as a set temperature of each of the front chamber A and the rear chamber B, and a heating / cooling period (a refrigerant introduction period to the evaporator) for each chamber. The storage unit 9 stores the measurement results of the room temperature sensors 17A and 17B and the pressure sensor 18, the set temperatures of the front chamber A and the rear chamber B, and other information.
[0027]
The operation of the refrigeration apparatus for a vehicle configured as shown in FIG. Cooling operation mode for both front and rear chambers], [2. Heating operation mode for both front and rear rooms], [3. Front chamber cooling, rear chamber heating operation mode], [4. Front chamber heating, rear chamber cooling operation mode], [5. Defrost operation mode], [6. Prechamber oil return operation mode], [7. Each mode of the rear chamber oil return operation mode] will be described.
[1. When the cooling operation mode for both the front chamber and the rear chamber] is selected, the following three modes are selectively executed.
[▲ 1 ▼ Parallel cooling mode in front and rear rooms]
When this mode is selected, the on-off valves 10C, 10D, 12, 14, and 15 are closed, and the on-off valves 10A and 10B are opened. The refrigerant compressed by the compressor 1 is in a high-temperature and high-pressure gas phase, and the discharge pressure adjustment valve 13 is opened and flows into the condenser 2 at PHset or higher. The refrigerant flowing into the condenser 2 gives heat to the outdoor air and condenses itself into a high-temperature and high-pressure liquid refrigerant. The condensed and liquefied refrigerant flows through the receiver 6 and the on-off valves 10A and 10B, adiabatically expands in the process of flowing through the expansion valves 3A and 3B, and becomes a low-temperature and low-pressure liquid refrigerant and flows in parallel to the evaporators 4A and 4B. To do. The refrigerant flowing into the evaporators 4A and 4B cools the air in the front chamber A and the rear chamber B, and evaporates itself to become a low-temperature and low-pressure gas refrigerant. The evaporated and vaporized refrigerant flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above process is repeated.
[0028]
[▲ 2 ▼ Cooling mode for front chamber only (temperature control stopped for rear chamber)]
When this mode is selected, the on-off valves 10B, 10C, 10D, 12, 14, and 15 are closed, and only the on-off valve 10A is opened. The refrigerant compressed by the compressor 1 is in a high-temperature and high-pressure gas phase, and the discharge pressure adjustment valve 13 is opened and flows into the condenser 2 at PHset or higher. The refrigerant flowing into the condenser 2 gives heat to the outdoor air and condenses itself into a high-temperature and high-pressure liquid refrigerant. The condensed and liquefied refrigerant flows through the receiver 6 and the on-off valve 10A, adiabatically expands in the process of flowing through the expansion valve 3A, and flows into the evaporator 4A as a low-temperature and low-pressure liquid refrigerant. The refrigerant flowing into the evaporator 4A cools the air in the front chamber A and evaporates itself to become a low-temperature and low-pressure gas refrigerant. The evaporated and vaporized refrigerant flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above process is repeated.
[0029]
[(3) Cooling of rear chamber only (temperature control stopped in front chamber) mode]
When this mode is selected, the on-off valves 10A, 10C, 10D, 12, 14, and 15 are closed, and only the on-off valve 10B is opened. The refrigerant compressed by the compressor 1 is in a high-temperature and high-pressure gas phase, and the discharge pressure adjustment valve 13 is opened and flows into the condenser 2 at PHset or higher. The refrigerant flowing into the condenser 2 gives heat to the outdoor air and condenses itself into a high-temperature and high-pressure liquid refrigerant. The condensed and liquefied refrigerant flows through the receiver 6 and the on-off valve 10B, adiabatically expands in the process of flowing through the expansion valve 3B, and flows into the evaporator 4B as a low-temperature and low-pressure liquid refrigerant. The refrigerant that has flowed into the evaporator 4B cools the air in the rear chamber B, and evaporates to become a low-temperature and low-pressure gas refrigerant. The evaporated and vaporized refrigerant flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above process is repeated.
[0030]
[2. When the heating operation mode is selected for both the front chamber and the rear chamber, the following three modes are selectively executed.
[▲ 4 ▼ Front and rear chamber parallel heating mode]
When this mode is selected, the on-off valves 10A, 10B, 12, 14, and 15 are closed, and the on-off valves 10C and 10D are opened. However, as will be described in detail later, the on-off valves 14 and 15 are controlled to open and close as needed even when the initial state is closed. The refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas phase, and as long as the pressure is lower than PHset, it does not flow into the capacitor 2 but flows through the bypass pipe L2 and reaches the PLset by the constant pressure expansion valve 11. The pressure is reduced while maintaining the gas phase. The decompressed refrigerant flows through the on-off valves 10C and 10D and is introduced into the evaporators 4A and 4B in parallel. In the evaporators 4A and 4B, the introduced refrigerant in the gas phase state dissipates heat without condensing, and heats the air in the front chamber A and the rear chamber B. The radiated refrigerant becomes a low-temperature and low-pressure gas-phase state, flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above-described process is repeated.
[0031]
[(5) Only the front chamber is heated (temperature control is stopped in the rear chamber) mode]
When this mode is selected, the on-off valves 10A, 10B, 10D, 12, 14, and 15 are closed, and only the on-off valve 10C is opened (details of control of the on-off valves 14 and 15 will be described later). The refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas phase, and as long as the pressure is lower than PHset, it does not flow into the capacitor 2 but flows through the bypass pipe L2 and reaches the PLset by the constant pressure expansion valve 11. The pressure is reduced while maintaining the gas phase. The decompressed refrigerant flows through the on-off valve 10C and is introduced into the evaporator 4A. In the evaporator 4A, the introduced gas-phase refrigerant dissipates heat without condensing, and heats the air in the front chamber A. The radiated refrigerant becomes a low-temperature and low-pressure gas-phase state, flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above-described process is repeated.
[0032]
[(6) Only the rear chamber is heated (temperature control is stopped in the front chamber) mode]
When this mode is selected, the on-off valves 10A, 10B, 10C, 12, 14, and 15 are closed, and only the on-off valve 10D is opened (details of control of the on-off valves 14 and 15 will be described later). The refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas phase, and as long as the pressure is lower than PHset, it does not flow into the capacitor 2 but flows through the bypass pipe L2 and reaches the PLset by the constant pressure expansion valve 11. The pressure is reduced while maintaining the gas phase. The decompressed refrigerant flows through the on-off valve 10D and is introduced into the evaporator 4B. In the evaporator 4B, the introduced gas-phase refrigerant dissipates heat without condensing, and heats the air in the rear chamber B. The radiated refrigerant becomes a low-temperature and low-pressure gas-phase state, flows through the accumulator 5, is sucked into the compressor 1 and compressed, and thereafter, the above-described process is repeated.
[0033]
In the following, the above-mentioned [2. The control executed when the heating operation mode for both the front and rear rooms is selected will be described with reference to the flowcharts shown in FIGS. Note that the on-off valves 10A to 10D, 12, 14, and 15 are all closed at the beginning of the control.
As a previous stage, the control unit 7 determines whether or not the heating operation mode of both the front chamber A and the rear chamber B is possible while referring to various setting values stored in the storage unit 9. It is assumed that the control unit 7 performs a process of storing various setting values received via the input unit 8 in a predetermined area of the storage unit 9 at an arbitrary timing. A specific determination sequence is as follows.
First, the control unit 7 measures the chamber temperatures Ft and Rt of the front chamber A and the rear chamber B using the room temperature sensors 17A and 17B (step 101). Next, the control unit 7 sets the target temperature (setting) of the rear chamber B in which the internal temperature Ft is lower than the target temperature (set temperature) Fset of the front chamber A set in advance and the internal temperature Rt is set in advance. It is determined whether or not the temperature is lower than Rset (step 102).
[0034]
When it is determined that the internal temperature Ft is lower than the set temperature Fset and the internal temperature Rt is lower than the set temperature Rset, the control unit 7 opens the on-off valves 10C and 10D [4] , The rear-chamber parallel heating mode] (step 103), otherwise, the heating operation mode for both the front and rear chambers is completed, or the transition to the one-chamber heating and one-chamber cooling mode is performed. Is selected (step 104).
[0035]
When shifting to [4] Pre-chamber and rear-chamber parallel heating mode, the control unit 7 performs a heating operation while preventing a pressure drop on the low pressure side. Specifically, the pressure sensor 18 measures the low-pressure side pressure PL (step 105), and then determines whether or not the low-pressure side pressure PL is lower than the set pressure PLset (step 106). When the control unit 7 determines that the low-pressure side pressure PL is not lower than the suction pressure PLset, it is assumed that the circulating refrigerant amount is sufficiently secured (even if the PLset has an allowable range, When the process proceeds to step 116 described later (assuming that it is at least within an allowable range) and it is determined that the low pressure side pressure PL is lower than the suction pressure PLset, it is determined that the circulating refrigerant amount is insufficient and the opening / closing is performed. The valve 14 is opened to supply a part of the liquid phase refrigerant held inside the receiver 6 to the low pressure side of the refrigerant pipe L1 (step 107).
[0036]
Next, the control unit 7 determines whether, for example, 30 seconds have elapsed since the start of [4] front chamber, rear chamber parallel heating mode] (step 108). The controller 7 continues the current state until 30 seconds have elapsed, and when the 30 seconds have elapsed, measures the low pressure side pressure PL (step 109), and then the low pressure side pressure PL is greater than the set pressure PLset. It is determined whether or not it is low (step 110). Thus, the reason for setting and determining the predetermined time interval is that the refrigerant is derived using the pressure difference between the receiver 6 and the refrigerant pipe L1, and therefore it takes time to supply the refrigerant.
And the control part 7 determines the effect in the state which made the residual refrigerant | coolant derivation low-pressure control means function, and transfers to the step according to it. Specifically, when it is determined that the low-pressure side pressure PL is not lower than the set pressure PLset, after closing the on-off valve 14 (step 111), the process returns to the above-described step 105 and the above processing is repeated. If it is determined that the low pressure side pressure PL is lower than the set pressure PLset, the refrigerant remaining in the receiver 6 cannot be supplied with the differential pressure of the receiver 6, and the on-off valve 15 is opened to discharge the discharged refrigerant to the receiver 6 side. A part of the refrigerant in the gas phase state introduced and held in the receiver 6 is supplied to the bypass pipe L2 (step 112).
[0037]
Next, the control unit 7 measures the low-pressure side pressure PL in order to determine the effect in a state where the discharge refrigerant introduction low-pressure control unit is functioning (step 113), and then the low-pressure side pressure PL is greater than the set pressure PLset. It is determined whether or not the value is lower (step 114). When the control unit 7 determines that the low pressure side pressure PL is lower than the set pressure PLset, the control unit 7 returns to step 113 and repeats the above processing in order to make the discharged refrigerant introduction low pressure control unit function as it is. When it is determined that the pressure PL is not lower than the set pressure PLset, that is, it has recovered from the pressure drop state, the on-off valves 14 and 15 are closed to cut off the supply of the liquid-phase refrigerant from the receiver 6 to the refrigerant pipe L1 ( Step 115).
[0038]
Next, the controller 7 measures the internal temperature Rt (step 116), and then determines whether or not the internal temperature Rt is higher than the set temperature Rset (step 117). When the controller 7 determines that the internal temperature Rt is higher than the set temperature Rset, the control unit 7 proceeds to step 120 shown in FIG. 4 to be described later, performs the heating operation only in the front chamber, and the internal temperature Rt is If it is determined that the temperature is not higher than the set temperature Rset, the internal temperature Ft is measured to determine whether or not to continue the two-chamber heating control (step 118), and then the internal temperature Ft is set to the set temperature. It is determined whether it is higher than Fset (step 119). When the controller 7 determines that the internal temperature Ft is not higher than the set temperature Fset, the controller 7 returns to step 105 described above to continue the two-chamber heating operation, and the internal temperature Ft is higher than the set temperature Fset. If it is determined, the process proceeds to step 136 shown in FIG. 6 to be described later, and the heating operation of only the rear chamber is performed.
[0039]
Hereinafter, control in the heating mode of only one room will be described.
When the controller 7 determines in step 117 that the internal temperature Rt is higher than the set temperature Rset, the controller 7 closes the on-off valve 10D and shifts to [5] Only the front chamber heating mode] (step 120). When shifting to this mode, the controller 7 first measures the low-pressure side pressure PL (step 121), and then determines whether or not the low-pressure side pressure PL is lower than the suction pressure PLset (step 122). When the control unit 7 determines that the low pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 proceeds to step 132 described later, and when the control unit 7 determines that the low pressure side pressure PL is lower than the suction pressure PLset, The on-off valve 14 is opened to supply a part of the liquid phase refrigerant held in the receiver 6 to the low pressure side of the refrigerant pipe L1 (step 123).
[0040]
Next, the control unit 7 determines whether, for example, 30 seconds has elapsed since the start of [5] Only the front chamber heating mode] (step 124). The controller 7 continues the current state until 30 seconds have elapsed, and when the 30 seconds have elapsed, measures the low-pressure side pressure PL (step 125), and then the low-pressure side pressure PL is greater than the suction pressure PLset. It is determined whether or not it is low (step 126). When the control unit 7 determines that the low pressure side pressure PL is not lower than the suction pressure PLset, after closing the on-off valve 14 (step 127), the control unit 7 returns to step 121 and repeats the above processing. When it is determined that the suction pressure PLset is lower than the low pressure side pressure PL, the on-off valve 15 is opened to introduce the discharged refrigerant to the receiver 6 side, and a part of the refrigerant in the gas phase state held inside the receiver 6 Is supplied to the bypass pipe L2 (step 128).
[0041]
Next, the control unit 7 measures the low pressure side pressure PL (step 129), and then determines whether or not the low pressure side pressure PL is lower than the suction pressure PLset (step 130). When the control unit 7 determines that the low pressure side pressure PL is lower than the suction pressure PLset, the control unit 7 returns to the above-described step 129 and repeats the above processing, and determines that the low pressure side pressure PL is not lower than the suction pressure PLset. If this happens, the on-off valves 14 and 15 are closed, and the supply of the liquid phase refrigerant from the receiver 6 to the refrigerant pipe L1 is cut off (step 131).
[0042]
Next, the controller 7 measures the internal temperature Rt (step 132), and then determines whether or not the internal temperature Rt is higher than the set temperature Rset (step 133). When the controller 7 determines that the internal temperature Rt is not higher than the set temperature Rset, the control unit 7 returns to the above-described step 105 and repeats the above processing, and determines that the internal temperature Rt is higher than the set temperature Rset. If so, the internal temperature Ft is measured (step 134), and then it is determined whether or not the internal temperature Ft is higher than the set temperature Fset (step 135). When the control unit 7 determines that the internal temperature Ft is not higher than the set temperature Fset, the control unit 7 returns to the above-described step 120 and repeats the above processing, and determines that the internal temperature Ft is higher than the set temperature Fset. If so, the process proceeds to step 152 described later.
[0043]
If the controller 7 determines in step 119 that the internal temperature Ft is higher than the set temperature Fset, the controller 7 closes the on-off valve 10C and shifts to [6] Only the rear chamber heating mode] (step 136). When shifting to this mode, the controller 7 first measures the low-pressure side pressure PL (step 137), and then determines whether or not the low-pressure side pressure PL is lower than the suction pressure PLset (step 138). When the control unit 7 determines that the low pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 proceeds to step 148 described later, and when it is determined that the low pressure side pressure PL is lower than the suction pressure PLset, The on-off valve 14 is opened and a part of the liquid phase refrigerant held inside the receiver 6 is supplied to the low pressure side of the refrigerant pipe L1 (step 139).
[0044]
Next, the controller 7 determines whether or not, for example, 30 seconds have elapsed since the start of [6) Only the rear chamber heating mode] (step 140). The controller 7 continues the current state until 30 seconds have elapsed, and when the 30 seconds have elapsed, measures the low-pressure side pressure PL (step 141), and then the low-pressure side pressure PL is greater than the suction pressure PLset. It is determined whether or not it is low (step 142). When the control unit 7 determines that the low pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 closes the on-off valve 14 (step 143), returns to the above-described step 137, and repeats the above processing. When it is determined that the low pressure side pressure PL is lower than the suction pressure PLset, the on-off valve 15 is opened to introduce the discharged refrigerant to the receiver 6 side, and a part of the refrigerant in the gas phase state held inside the receiver 6 Is supplied to the bypass pipe L2 (step 144).
[0045]
Next, the control unit 7 measures the low pressure side pressure PL (step 145), and then determines whether or not the low pressure side pressure PL is lower than the suction pressure PLset (step 146). When the control unit 7 determines that the low pressure side pressure PL is lower than the suction pressure PLset, the control unit 7 returns to the above-described step 145 and repeats the above processing, and determines that the low pressure side pressure PL is not lower than the suction pressure PLset. In that case, the on-off valves 14 and 15 are closed and the supply of the liquid-phase refrigerant from the receiver 6 to the refrigerant pipe L1 is cut off (step 147).
[0046]
Next, the controller 7 measures the internal temperature Ft (step 148), and then determines whether or not the internal temperature Ft is higher than the set temperature Fset (step 149). When the controller 7 determines that the internal temperature Ft is not higher than the set temperature Fset, the control unit 7 returns to the above-described step 105 and repeats the above processing, and determines that the internal temperature Ft is higher than the set temperature Fset. If so, the internal temperature Rt is measured (step 150), and then it is determined whether the internal temperature Rt is higher than the set temperature Rset (step 151). When the controller 7 determines that the internal temperature Rt is not higher than the set temperature Rset, the control unit 7 returns to the above-described step 136 and repeats the above processing, and determines that the internal temperature Rt is higher than the set temperature Rset. If so, the compressor 1 is stopped (step 152), and the [heating operation mode for both the front chamber and the rear chamber] is terminated.
[0047]
[3. When “front chamber cooling / rear chamber heating operation mode” is selected, “(2) cooling only front chamber (temperature control stopped for rear chamber)” described above and “(6) heating only rear chamber ( The anterior chamber temperature control stop mode) is executed alternately.
In the following, the above [3. Control executed when “front chamber cooling, rear chamber heating operation mode” is selected will be described with reference to the flowcharts shown in FIGS. Note that the on-off valves 10A to 10D, 12, 14, and 15 are all closed at the beginning of control.
As a previous stage, the control unit 7 determines whether or not the cooling operation mode of the front chamber A and the heating operation mode of the rear chamber B are possible while referring to various set values stored in the storage unit 9. It is assumed that the control unit 7 performs a process of storing various setting values received via the input unit 8 in a predetermined area of the storage unit 9 at an arbitrary timing. A specific determination sequence is as follows.
First, the control unit 7 measures the front chamber A and the chamber temperatures Ft and Rt by the room temperature sensors 17A and 17B, respectively (step 201). Next, the control unit 7 determines whether or not the internal temperature Ft is higher than a preset target temperature (set temperature) Fset and the internal temperature Rt is lower than a preset target temperature (set temperature) Rset. Is determined (step 202).
[0048]
When the controller 7 determines that the internal temperature Ft is higher than the set temperature Fset and the internal temperature Rt is lower than the set temperature Rset, the control unit 7 opens the on-off valve 10A and [2] cools only the front chamber. [Temperature control stop for rear chamber] mode] (step 203), otherwise [end chamber cooling, rear chamber heating operation mode] end, [cooling operation mode for both front chamber and rear chamber] Alternatively, the transition to [one-chamber heating, one-chamber cooling mode] is selected (step 204).
[0049]
When shifting to [(2) Cooling mode only in the front chamber], the control unit 7 determines whether, for example, 30 seconds have elapsed since the start of the mode (step 205). The controller 7 continues the current state as long as 30 seconds have not elapsed, measures the internal temperature Ft when 30 seconds have elapsed (step 206), and then the internal temperature Ft is higher than the set temperature Fset. It is determined whether or not it is high (step 207). When the controller 7 determines that the internal temperature Ft is not higher than the set temperature Fset, the control unit 7 proceeds to step 223 described later, and when the internal temperature Ft is determined to be higher than the set temperature Fset, The on-off valve 10A is closed and the on-off valve 10D is opened to shift to [6] Only the rear chamber is heated (temperature control is stopped in the front chamber) mode (step 208).
[0050]
When [(6) rear chamber only heating mode] is entered, the control unit 7 measures the internal temperature Rt (step 209), and then determines whether the internal temperature Rt is higher than the set temperature Rset. (Step 210). When the controller 7 determines that the internal temperature Rt is not higher than the set temperature Rset, the control unit 7 proceeds to step 239 described later, and when the internal temperature Rt is determined to be higher than the set temperature Rset, For example, it is determined whether or not 2 minutes have elapsed since the start of [(2) Cooling mode for front chamber only] (step 211). If 2 minutes have not elapsed, the control unit 7 returns to the above-described step 203 and repeats the above processing, and when 2 minutes have elapsed, measures the low pressure side pressure PL (step 212). It is determined whether or not it is lower than the suction pressure PLset (step 213). When the control unit 7 determines that the low-pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 returns to the above-described step 209 and repeats the above processing to determine that the low-pressure side pressure PL is lower than the suction pressure PLset. In this case, the on-off valve 14 is opened and a part of the liquid phase refrigerant held inside the receiver 6 is supplied to the low pressure side of the refrigerant pipe L1 (step 214).
[0051]
Next, the controller 7 determines whether or not, for example, 30 seconds have elapsed since the start of [6) Only the rear chamber heating mode] (step 215). The controller 7 continues the current state until 30 seconds have elapsed, and when the 30 seconds have elapsed, measures the low-pressure side pressure PL (step 216), and then the low-pressure side pressure PL is greater than the suction pressure PLset. It is determined whether or not it is low (step 217). When the control unit 7 determines that the low pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 closes the on-off valve 14 (step 218), returns to the above-described step 209, and repeats the above processing. When it is determined that the low pressure side pressure PL is lower than the suction pressure PLset, the on-off valve 15 is opened to introduce the discharged refrigerant to the receiver 6 side, and a part of the refrigerant in the gas phase state held inside the receiver 6 Is supplied to the bypass pipe L2 (step 219).
[0052]
Next, the control unit 7 measures the low pressure side pressure PL (step 220), and then determines whether or not the low pressure side pressure PL is lower than the suction pressure PLset (step 221). If the control unit 7 determines that the low-pressure side pressure PL is lower than the suction pressure PLset, the control unit 7 returns to the above-described step 220 and repeats the above processing to determine that the low-pressure side pressure PL is not lower than the suction pressure PLset. In this case, the on-off valves 14 and 15 are closed, the supply of the liquid-phase refrigerant from the receiver 6 to the refrigerant pipe L1 is cut off (step 222), and the process returns to the above-described step 209 to repeat the above processing.
[0053]
When the control unit 7 determines in step 207 that the internal temperature Ft is not higher than the set temperature Fset, the control unit 7 closes the on-off valve 10A and opens the on-off valve 10D [(6) Only the rear chamber heating mode]. Transition is made (step 223). When shifting to this mode, the controller 7 first measures the internal temperature Rt (step 224), and then determines whether the internal temperature Rt is lower than the set temperature Rset (step 225). When the control unit 7 determines that the internal temperature Rt is not lower than the set temperature Rset, the control unit 7 proceeds to step 245 described later, and when the internal temperature Rt is determined to be lower than the set temperature Rset, The internal temperature Ft is measured (step 226), and then it is determined whether the internal temperature Ft is lower than the set temperature Fset (step 227). When the controller 7 determines that the internal temperature Ft is not lower than the set temperature Fset, the control unit 7 returns to the above-described step 203 and repeats the above processing, and determines that the internal temperature Ft is lower than the set temperature Fset. If so, the low pressure side pressure PL is measured (step 228), and then it is determined whether or not the low pressure side pressure PL is lower than the suction pressure PLset (step 229). When the control unit 7 determines that the low-pressure side pressure PL is not smaller than the suction pressure PLset, the control unit 7 returns to the above-described step 224 and repeats the above processing to determine that the low-pressure side pressure PL is lower than the suction pressure PLset. In that case, the on-off valve 14 is opened and a part of the liquid-phase refrigerant held in the receiver 6 is supplied to the low-pressure side of the refrigerant pipe L1 (step 230).
[0054]
Next, the control unit 7 determines whether or not, for example, 30 seconds have elapsed since the start of [6] Only the rear chamber heating mode] (step 231). The controller 7 continues the current state until 30 seconds have elapsed, and when the 30 seconds have elapsed, measures the low pressure side pressure PL (step 232), and then the low pressure side pressure PL is greater than the suction pressure PLset. It is determined whether or not it is low (step 233). When the low-pressure side pressure PL is not lower than the suction pressure PLset, the control unit 7 closes the on-off valve 14 (step 234), returns to the above-described step 224, repeats the above processing, and repeats the low-pressure side pressure. When it is determined that PL is lower than the suction pressure PLset, the on-off valve 15 is opened to introduce the discharged refrigerant to the receiver 6 side, and a part of the gas-phase refrigerant held inside the receiver 6 is bypassed. Supply to L2 (step 235).
[0055]
Next, the control unit 7 measures the low pressure side pressure PL (step 236), and then determines whether or not the low pressure side pressure PL is lower than the suction pressure PLset (step 237). If the control unit 7 determines that the low-pressure side pressure PL is lower than the suction pressure PLset, the control unit 7 returns to the above-described step 236 and repeats the above processing to determine that the low-pressure side pressure PL is not lower than the suction pressure PLset. In this case, the on-off valves 14 and 15 are closed, the supply of the liquid phase refrigerant from the receiver 6 to the refrigerant pipe L1 is cut off (step 238), the process returns to the above-described step 224 and the above processing is repeated.
[0056]
When the controller 7 determines in step 210 that the internal temperature Rt is not higher than the set temperature Rset, the controller 7 closes the on-off valve 10D and opens the on-off valve 10A [(2) Only the front chamber is in the cooling mode]. Transition is made (step 239). When shifting to this mode, the control unit 7 first determines whether, for example, 30 seconds have elapsed since the start of the mode (step 240). The controller 7 continues the current state as long as 30 seconds have not elapsed, measures the internal temperature Rt when 30 seconds have elapsed (step 241), and then the internal temperature Rt is higher than the set temperature Rset. It is determined whether or not it is low (step 242). When the controller 7 determines that the internal temperature Rt is lower than the set temperature Rset, the control unit 7 returns to the above-described step 203 and repeats the above processing, and determines that the internal temperature Rt is not lower than the set temperature Rset. If so, the internal temperature Ft is measured (step 243), and then it is determined whether the internal temperature Ft is higher than the set temperature Fset (step 244). When it is determined that the internal temperature Ft is higher than the set temperature Fset, the control unit 7 returns to the above-described step 239 and repeats the above processing, and determines that the internal temperature Ft is not higher than the set temperature Fset. If so, the compressor 1 is stopped (step 245) and the [front chamber cooling, rear chamber heating operation mode] is terminated.
[0057]
[4. When “front chamber heating / rear chamber cooling operation mode” is selected, “(5) heating only front chamber (temperature control stopped for rear chamber)” described above and “(3) cooling only rear chamber ( The anterior chamber temperature control stop mode) is executed alternately.
[0058]
[5. When the “defrost operation mode” is selected, the above-described [4] front chamber and rear chamber parallel heating mode] is executed. However, in both the front chamber A and the rear chamber B, the evaporator fan (not shown) that circulates the air in the cabinet is stopped, and the sensor (surface temperature of the evaporator coil, etc.) that determines the end of the defrost installed in each chamber is measured. When the target temperature is reached, the on-off valves 10C and 10D are closed.
[0059]
[6. When the front chamber oil return operation mode] is selected, the on-off valves 10A, 10B, 10D, 14, and 15 are closed, and the on-off valves 10C and 12 are opened. The refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas phase, and the pressure becomes smaller than PHset when the on-off valve 12 is opened, and flows through the bypass pipe L2 without flowing into the capacitor 2. . The refrigerant flowing into the bypass pipe L2 bypasses the constant pressure expansion valve 11 and flows through the on-off valve 10C and is introduced into the evaporator 4A. The gas-phase refrigerant introduced into the evaporator 4 </ b> A discharges the oil accumulated inside from the evaporator 4 </ b> A and introduces it into the accumulator 5. The gas-phase refrigerant that has been gas-liquid separated in the accumulator 5 is sucked into the compressor 1 and compressed, and thereafter the above process is repeated.
[0060]
[7. When the rear chamber oil return operation mode] is selected, the on-off valves 10A, 10B, 10C, 14, 15 are closed, and the on-off valves 10B, 10D, 12 are opened. The refrigerant compressed by the compressor 1 becomes a high-temperature and high-pressure gas phase, and does not flow into the capacitor 2 but flows through the bypass pipe L2. The refrigerant flowing into the bypass pipe L2 bypasses the constant pressure expansion valve 11 and flows through the on-off valve 10D, and is introduced into the evaporator 4B. The gas-phase refrigerant introduced into the evaporator 4 </ b> B discharges the oil accumulated inside from the evaporator 4 </ b> B and introduces it into the accumulator 5. The gas-phase refrigerant that has been gas-liquid separated in the accumulator 5 is sucked into the compressor 1 and compressed, and thereafter the above process is repeated.
[0061]
In the vehicular refrigeration apparatus configured as described above, the high-temperature and high-pressure gas-phase refrigerant discharged from the compressor 1 is depressurized to a temperature equal to or lower than the interior temperature saturation pressure of the front chamber A and the rear chamber B placed in a heated state. Then, if the refrigerant is introduced directly into the evaporators 4A and 4B without going through the condenser 2 and the expansion valves 3A and 3B, the introduced refrigerant dissipates heat without condensing in the evaporator. As a result, it is possible to perform a heating operation without separately constructing a pipe for introducing the cooling water into the cabinet as in the conventional warm water cooling system, and the mounting of the refrigeration apparatus on the vehicle can be simplified. .
[0062]
In addition, the system that realizes the refrigeration cycle is in a single-phase state of superheated gas, and there is no need to keep the liquid refrigerant in the accumulator as in the conventional hot gas refrigerant heating method, so that the amount of refrigerant that functions substantially is sufficient. Because it is secured, performance degradation does not occur. Furthermore, since liquid refrigerant is not stored in the accumulator, phenomena such as liquid return and oil dilution do not occur. In addition, when the transition from the heating operation to the cooling operation is performed, most of the refrigerant is held in the condenser / receiver, so that the loss during the transition period is small, and a rapid transition is possible.
[0063]
In the above vehicle refrigeration apparatus, by providing the discharge pressure adjusting valve 13, the high-pressure side refrigerant pressure is maintained at a predetermined pressure (high pressure; PHset), so that the state of the high-pressure side refrigerant is stabilized. Efficient heating can be realized.
[0064]
Further, by providing the liquid return pipe L4 and the on-off valve 14 forming the first low-pressure control means, and the gas return pipe L5 and the on-off valve 15 forming the second low-pressure control means, the refrigerant pressure on the low-pressure side is predetermined. Therefore, it is possible to achieve efficient heating by stabilizing the state of the refrigerant on the low pressure side.
[0065]
In the above vehicle refrigeration system, heating operation and normal cooling that maintain a single-phase state of the superheated gas until either one of the front chamber A and the rear chamber B is heated or cooled to a target set temperature. By alternately performing the operation, the one-chamber heating and the one-chamber cooling operations can be performed quickly and efficiently.
[0066]
Note that the values such as the set temperature Fset of the front chamber A, the set temperature Rset of the rear chamber B, and the time for which the first low-pressure control means functions in advance (30 seconds in this embodiment) used in this embodiment are input units. 8 can be changed as appropriate, and it is needless to say that a comfortable driving can be realized by changing the setting according to various requests.
[0067]
【The invention's effect】
As described above, according to the present invention, it is possible to perform a heating operation without separately constructing a pipe for introducing cooling water into the warehouse as in the conventional warm water cooling method, and the refrigeration apparatus for the vehicle can be operated. The bodywork can be simplified. In addition, the system that realizes the refrigeration cycle is in a single-phase state of superheated gas, and there is no need to keep the liquid refrigerant in the accumulator as in the conventional hot gas refrigerant heating method, so that the amount of refrigerant that functions substantially is sufficient. Because it is secured, performance degradation does not occur. Furthermore, since liquid refrigerant is not stored in the accumulator, phenomena such as liquid return and oil dilution do not occur. In addition, when the transition from the heating operation to the cooling operation is performed, most of the refrigerant is held in the condenser / receiver, so that the loss during the transition period is small, and a rapid transition is possible.
[0068]
According to the present invention, the refrigerant pressure on the high-pressure side is maintained at a predetermined pressure (high pressure) by letting a part of the gas-phase refrigerant discharged from the compressor escape to the condenser and reduce the pressure. It is possible to achieve efficient heating by stabilizing the state of the refrigerant.
[0069]
According to the present invention, a part of the gas-phase refrigerant held in the receiver is added to the refrigerant in the system to increase the pressure, or a part of the liquid-phase refrigerant held in the receiver is also increased in the system. By increasing the pressure in addition to the refrigerant, the refrigerant pressure on the low pressure side is maintained at a predetermined pressure (low pressure), so that the state of the refrigerant on the low pressure side can be stabilized and efficient heating can be realized.
[0070]
According to the present invention, the heating operation in which the superheated gas is kept in the single phase state and the normal cooling operation are alternately performed as described above, so that the one-chamber heating operation and the one-chamber cooling operation are performed quickly and efficiently. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention, and is a diagram showing an outline of a vehicular refrigeration apparatus having two cold storage units.
2 is a flowchart for explaining control executed when [heating operation mode for both front chamber and rear chamber] is selected in the vehicular refrigeration apparatus of FIG. 1; FIG.
3 is a flowchart for explaining control executed when [heating operation mode for both front and rear chambers] is selected in the vehicular refrigeration apparatus of FIG.
4 is a flowchart for explaining the control executed when [the heating operation mode for both the front chamber and the rear chamber] is selected in the vehicular refrigeration apparatus of FIG.
FIG. 5 is also a flowchart for explaining control executed when [heating operation mode for both front and rear chambers] is selected in the vehicular refrigeration apparatus of FIG. 1;
6 is a flowchart for explaining control executed when [heating operation mode for both front and rear chambers] is selected in the vehicular refrigeration apparatus of FIG. 1; FIG.
7 is a flow chart for explaining control executed when [heating operation mode for both front and rear chambers] is selected in the vehicular refrigeration apparatus of FIG.
8 is a flowchart for explaining control executed when [front chamber cooling, rear chamber heating operation mode] is selected in the vehicular refrigeration apparatus of FIG. 1; FIG.
FIG. 9 is also a flowchart for illustrating control executed when [front chamber cooling, rear chamber heating operation mode] is selected in the vehicle refrigeration apparatus of FIG. 1;
FIG. 10 is also a flowchart for explaining control executed when [front chamber cooling, rear chamber heating operation mode] is selected in the vehicle refrigeration apparatus of FIG. 1;
11 is a flowchart for explaining the control executed when [front chamber cooling, rear chamber heating operation mode] is selected in the vehicular refrigeration apparatus of FIG. 1; FIG.
12 is a flowchart for explaining control executed when [front chamber cooling, rear chamber heating operation mode] is selected in the vehicular refrigeration apparatus of FIG. 1; FIG.
[Explanation of symbols]
1 Compressor
2 capacitors
3A, 3B expansion valve
4A, 4B evaporator
5 Accumulator
6 Receiver
7 Control unit
8 Input section
9 Memory part
10A, 10B On-off valve
10C, 10D open / close valve (open / close means)
11 Constant pressure expansion valve (pressure reduction means)
13 Discharge pressure adjustment valve (high pressure control means)
14 On-off valve
15 On-off valve
17A, 17B Room temperature sensor
18 Pressure sensor
L1 refrigerant piping
L2 Bypass piping (bypass)
L4 Liquid return piping
L5 Gas return piping

Claims (5)

A vehicular refrigeration apparatus in which a refrigeration cycle is configured by connecting a compressor, a condenser, a receiver, an expansion valve, and an evaporator through a refrigerant pipe,
The refrigerant in the gas phase discharged from the compressor bypasses the condenser and the expansion valve and is introduced into the evaporator, and the refrigerant flowing through the bypass is made to be equal to or lower than the internal temperature saturation pressure of the heat insulation. A pressure reducing means for reducing pressure and an opening / closing means for opening and closing the bypass to open and close the circulation of the refrigerant are provided, and the refrigerant that has dissipated heat in the evaporator and has entered a low-temperature and low-pressure gas phase state is higher than a predetermined pressure. A vehicle refrigeration apparatus comprising: a refrigerant discharge low-pressure control unit that adds a part of the liquid-phase refrigerant held by the receiver to the refrigerant when low . Claim 1 the gas-phase refrigerant state discharged from the compressor, characterized in that a pressure control means for introducing is higher than a predetermined pressure, a portion of the refrigerant in the gas-phase state to the condenser The vehicle refrigeration apparatus described. When the refrigerant that has dissipated heat in the evaporator and is in a low-temperature low-pressure gas-phase state is lower than a predetermined pressure, a part of the liquid-phase state refrigerant held in the receiver is discharged from the compressor to be added to the refrigerant. vehicle refrigeration apparatus of claim 1, wherein in that a refrigerant introducing low-pressure control means for introducing the receiver of the refrigerant. A vehicular refrigeration apparatus including two evaporators connected in parallel to a system that realizes a refrigeration cycle together with a compressor, a condenser, a receiver, and an expansion valve , and distributed to two cold storages,
The refrigerant in the gas phase discharged from the compressor is reduced in pressure by the pressure reducing means to the temperature equal to or lower than the internal temperature saturation pressure of the cold storage without passing through the condenser and the expansion valve, and then introduced into one evaporator. Heating operation to heat the cold storage of
A cooling operation for cooling the other cold storage by allowing the refrigerant in the gas phase state discharged from the compressor to be placed in the other evaporator on the refrigeration cycle is possible,
A control unit that alternately performs the heating operation or the cooling operation,
The control unit is configured to add a part of the liquid-phase refrigerant held by the receiver to the refrigerant when the refrigerant in a low-temperature and low-pressure gas-phase state is radiated by the evaporator and lower than a predetermined pressure. A vehicular refrigeration apparatus comprising a discharge low-pressure control means . A control method for a vehicular refrigeration apparatus comprising two evaporators connected in parallel to a system that realizes a refrigeration cycle together with a compressor, a condenser, a receiver, and an expansion valve , and distributed to two cold storages,
The refrigerant in the gas phase discharged from the compressor is reduced in pressure by the pressure reducing means to the temperature equal to or lower than the internal temperature saturation pressure of the cold storage without passing through the condenser and the expansion valve, and then introduced into one evaporator. Heating operation to heat the cold storage of
A cooling operation for cooling the other cold storage by allowing the refrigerant in the gas phase state discharged from the compressor to be placed in the other evaporator on the refrigeration cycle is possible,
When the heating operation or the cooling operation is alternately performed, and the refrigerant that has dissipated heat in the evaporator and has become a low-temperature and low-pressure gas-phase state is lower than a predetermined pressure, the liquid-state refrigerant held in the receiver A control method for a vehicular refrigeration apparatus , wherein a part of the refrigerant is added to the refrigerant to control a pressure to be equal to or higher than a set pressure .

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