JP2009216290A - Transport refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a directly-connected transport refrigerating device capable of solving a problem that a compressor is abnormally stopped (permanent stop) though a system is normal, and preventing incompatibility in temperature adjustment of goods loaded. <P>SOLUTION: In this directly-connected transport refrigerating device 3 which includes the compressor 4 driven by an engine 1B for driving a vehicle 1, and in which the compressor 4 is stopped and then automatically recovered when a discharged-refrigerant temperature Td of the compressor 4 is over a specified temperature Tmax, and it is considered that the system is abnormal, and the automatic recovery of the compressor 4 is forbidden when the motion is repeated by a prescribed number of times, a control section 23 is disposed to determine the normal or abnormal conditions of the system on the basis of a detection value of operational pressure, when the discharged-refrigerant temperature Td is the specified temperature Tmax or more, so that the compressor 4 is stopped and then automatically recovered when the system is normal, and the automatic recovery of the compressor 4 is forbidden when the system is abnormal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a direct-connection transport refrigeration apparatus in which a compressor is driven by a traveling engine of a vehicle.

  The direct-coupled transport refrigeration system uses a traveling engine of a vehicle as a power source, and the compressor is driven by a traveling engine via a belt and a clutch. For this reason, the rotation speed of the compressor depends on the rotation speed of the traveling engine and cannot be controlled by itself. In the transport refrigeration apparatus having such a configuration, when the refrigerant discharge temperature from the compressor exceeds a specified temperature, the operation of the compressor is stopped and automatically restored after a certain time, but the compressor is stopped or automatically restored. When the operation is repeated frequently, it is determined that there is an abnormality in the system, and automatic restoration is prohibited and the compressor is abnormally stopped (permanently stopped), thereby protecting the components of the refrigeration apparatus.

  On the other hand, Patent Document 1 discloses a refrigerant refrigeration apparatus that has a dedicated engine for a refrigeration system and that drives a compressor using power generated by a generator driven by the dedicated engine as a power source. When the pressure and discharge pressure are detected and at least one of these pressures deviates from the specified pressure range, the suction pressure adjustment valve opening or the compressor speed is controlled, and the intake pressure and discharge pressure are controlled within the specified range. Thus, a technique is disclosed in which the operation can be continued while protecting the components of the refrigeration apparatus, and damage to the load can be prevented.

JP-A-2005-61698

  However, in the above-described direct-coupled transport refrigeration system, the discharge refrigerant temperature rises abnormally and exceeds the specified temperature even when the system is normal at high loads when the temperature inside and outside the freezer and the rotational speed of the compressor are high, The compressor may stop and automatically return. For this reason, even if the system is normal, the compressor may be in an abnormal stop (permanent stop) state, and under severe operating conditions, there was a risk that the load would cause temperature control incompatibility. .

  The technique disclosed in Patent Document 1 includes an electric compressor that uses electric power generated by a generator driven by a dedicated engine as a power source, and is a type of transport refrigeration that can control the number of revolutions of the compressor by itself. It concerns the device. Therefore, such a technique cannot be employed in a direct-coupled transport refrigeration apparatus in which the rotational speed of the compressor depends on the rotational speed of the traveling engine and cannot be controlled by itself.

  The present invention has been made in view of such circumstances, and solves the problem that the compressor reaches an abnormal stop (permanent stop) even though the system is normal. It is an object of the present invention to provide a directly-coupled transport refrigeration apparatus that can be prevented.

In order to solve the above problems, the transport refrigeration apparatus of the present invention employs the following means.
In other words, a transport refrigeration apparatus according to the present invention includes a compressor driven by a vehicle traveling engine, and when the discharged refrigerant temperature of the compressor exceeds a specified temperature, the compressor is automatically returned after being stopped. In the direct-coupled transport refrigeration system that prohibits automatic return of the compressor when the operation is repeated a predetermined number of times, the refrigerant pressure is detected when the discharged refrigerant temperature is equal to or higher than the specified temperature. The system is characterized by determining whether the system is normal or abnormal based on the value, and when normal, the compressor is automatically restarted after being stopped, and when abnormal, the control unit prohibits the automatic return of the compressor. And

In a direct-coupled transport refrigeration system in which the compressor is driven by a vehicle travel engine, the rotational speed of the compressor depends on the rotational speed of the travel engine, so the temperature inside and outside the freezer and the rotational speed of the compressor When the load is high, even if the system is normal, the discharge refrigerant temperature may rise abnormally and exceed the specified temperature, and the compressor may stop and repeat automatic recovery. For this reason, although the system is normal, the compressor reaches an abnormal stop (permanent stop) state, and there is a risk that the load causes temperature control nonconformity.
In the present invention, when the discharged refrigerant temperature is equal to or higher than the specified temperature, the normality or abnormality of the system is determined based on the detected value of the refrigerant pressure, and when normal, the compressor is automatically restarted after being stopped. The control unit that prohibits the automatic recovery of the engine is provided, so when the discharged refrigerant temperature rises abnormally, the discharged refrigerant temperature is high because the system is abnormal or the discharged refrigerant temperature is high although the system is normal based on the refrigerant pressure. If the system is normal, the compressor can be stopped and then automatically returned to continue the refrigeration operation. Therefore, the problem that the compressor reaches an abnormally stopped (permanently stopped) state even though the system is normal can be solved, and the temperature control incompatibility of the load can be prevented. In addition, when the system is truly abnormal, it is possible to prohibit automatic return and place the compressor in an abnormally stopped state, thereby preventing damage to the equipment constituting the refrigeration apparatus.

  Furthermore, the transport refrigeration apparatus according to the present invention detects the suction pressure and the discharge pressure of the compressor as the refrigerant pressure in the transport refrigeration apparatus, and the refrigerant pressure is within the use limit of the compressor. When the upper region of the determination formula represented by the function of the suction pressure and the discharge pressure is determined to be normal, the system is automatically restored after the compressor is stopped, and the refrigerant pressure is lower than the lower region of the determination formula. In some cases, the system is determined to be abnormal, and the automatic return of the compressor is prohibited.

  According to the present invention, when the suction pressure and discharge pressure of the compressor are detected, and the refrigerant pressure is within the compressor use limit and is in the upper region of the determination formula represented by the function of the suction pressure and the discharge pressure, the system When the refrigerant pressure is in the lower region of the determination formula, the system is determined to be abnormal and the automatic return of the compressor is prohibited. The discharge refrigerant temperature has risen abnormally because the discharge pressure is high and the suction pressure is low even though the system is normal, or there is an abnormality such as a shortage of refrigerant in the system and the discharge is low If the temperature of the refrigerant is abnormally increased, it is determined whether the system is normal or abnormal. If the system is normal, the compressor can be automatically returned to continue operation under severe operating conditions. As a result, it is possible to prevent a temperature control failure of the cargo and improve the quality and reliability of the product.

  Furthermore, the transport refrigeration apparatus according to the present invention includes a compressor driven by a traveling engine of a vehicle, and when the high pressure in the system exceeds a specified pressure, the compressor is automatically returned after being stopped, In a direct-coupled transport refrigeration apparatus that, when the operation is repeated a predetermined number of times, considers a system abnormality and prohibits automatic return of the compressor, when the high pressure is not less than the specified pressure, the suction pressure of the compressor and A control unit is provided for determining whether the system is normal or abnormal based on a detected value of the discharged refrigerant temperature, and automatically restarting the compressor after stopping when it is normal, and prohibiting automatic return of the compressor when abnormal. It is characterized by.

  According to the present invention, when the high pressure is equal to or higher than the specified pressure, it is determined whether the system is normal or abnormal based on the detected values of the suction pressure and the discharge refrigerant temperature of the compressor, and when normal, the compressor is automatically restarted after being stopped. At the same time, it has a control unit that prohibits the automatic return of the compressor in the event of an abnormality, so even if the high pressure rises abnormally, if the system is normal, the compressor is stopped and then automatically returned to continue the refrigeration operation can do. In other words, the refrigerant temperature and pressure during operation are determined by the refrigerant physical properties and the performance of the compressor, heat exchanger, etc. For example, if the amount of refrigerant enclosed is large, excess refrigerant occupies the condenser and the heat transfer area decreases. , Ability decreases. Similarly, if the condenser fan fails and stops, the capacity decreases. In this case, even if the high pressure does not increase, the high pressure rises abnormally and the discharge temperature rises. Therefore, the normality / abnormality of the system is properly determined from the judgment formula expressed by the function of the compressor suction pressure and the discharge refrigerant temperature. can do. Therefore, the problem that the compressor reaches an abnormal stop (permanent stop) state even though the system is normal can be solved, and inadequate temperature control of the load can be prevented. In addition, when the system is truly abnormal, it is possible to prohibit automatic return and place the compressor in an abnormally stopped state, thereby preventing damage to equipment constituting the refrigeration apparatus.

  Furthermore, the transport refrigeration apparatus according to the present invention includes a compressor driven by a traveling engine of a vehicle, and when the high pressure in the system exceeds a specified pressure, the compressor is automatically returned after being stopped, In a direct-coupled transport refrigeration apparatus that prohibits the automatic return of the compressor when the operation is repeated a predetermined number of times, the outside air that is circulated to the condenser when the high pressure is equal to or higher than the specified pressure. A control unit is provided that determines whether the system is normal or abnormal based on a detected value of temperature, and when normal, the compressor is automatically restarted after being stopped, and when abnormal, prohibits automatic return of the compressor. It is characterized by that.

  According to the present invention, when the high pressure is equal to or higher than the specified pressure, it is determined whether the system is normal or abnormal based on the detected value of the outside air temperature flowing through the condenser, and when normal, the compressor is automatically restarted after being stopped. At the same time, it has a control unit that prohibits the automatic return of the compressor in the event of an abnormality, so even if the high pressure rises abnormally, if the system is normal, the compressor is stopped and then automatically returned to continue the refrigeration operation can do. That is, when the temperature of the outside air circulated through the condenser temporarily rises abnormally, for example, when the exhaust gas of another vehicle is circulated in parallel parking, the high pressure rises abnormally even if the system is normal. Thus, when the high pressure becomes abnormal when the temperature of the outside air flowing through the condenser is equal to or higher than a certain temperature, the system determines that the system is normal and automatically restores the compressor. Therefore, it is possible to solve the problem that the compressor reaches an abnormal stop (permanent stop) state even though the system is normal, and it is possible to prevent inadequate temperature regulation of the load. In addition, when the system is truly abnormal, it is possible to prohibit automatic return and place the compressor in an abnormally stopped state, thereby preventing damage to equipment constituting the refrigeration apparatus.

  According to the present invention, even if the discharge refrigerant temperature or high pressure rises abnormally and the compressor stops, the normality and abnormality of the system are accurately determined, and when the system is normal, the compressor is automatically returned to freezing. Since the operation can be continued, it is possible to solve the problem that the compressor reaches an abnormal stop (permanent stop) state even though the system is normal, and it is possible to prevent inadequate temperature regulation of the load. In addition, when the system is truly abnormal, automatic return can be prohibited and the compressor can be brought into an abnormally stopped state, so that damage to the devices constituting the refrigeration apparatus can be prevented.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a side view of a refrigeration vehicle 1 to which a transport refrigeration apparatus 3 according to a first embodiment of the present invention is applied. The refrigerated vehicle 1 includes a cabin 1A and a traveling engine 1B, and the freezer 2 is mounted on the rear chassis of the cabin 1A. The freezer 2 is constituted by a box body having a heat insulating structure, and includes a luggage loading / unloading door (not shown) on a rear surface or a side surface.

  The transport refrigeration apparatus 3 has a configuration in which a condenser unit 5 and an evaporator unit 6 are integrated, with a part of the refrigeration apparatus 3 protruding above the cabin 1A at a position above the front wall 2A of the freezer 2. It is fixedly installed. The evaporator unit 6 communicates with the inside of the freezer 2 and is configured so that the inside air can be circulated to the evaporator unit 6. The compressor 4 constituting the transport refrigeration apparatus 3 is installed on the side wall of the traveling engine 1B in the engine room on the cabin 1A side, and is driven by the traveling engine 1B via a belt and a clutch 4A (see FIG. 2). Can be driven.

  FIG. 2 shows a refrigeration cycle diagram of the transport refrigeration apparatus 3. The refrigeration cycle 7 uses the traveling engine 1B as a power source, the compressor 4 that compresses the refrigerant gas, and the condenser 8 that condenses the high-temperature and high-pressure refrigerant gas sent from the compressor 4 by exchanging heat with the outside air, A receiver 9 that stores the liquid refrigerant condensed in the condenser 8, a supercooler 10 that heat-cools the liquid refrigerant with a gas refrigerant from the evaporator 12 and supercools the liquid refrigerant, and adiabatic expansion of the subcooled liquid refrigerant. An expansion valve 11, an evaporator 12 that exchanges heat between the adiabatically expanded refrigerant and the air in the freezer 2, and an accumulator that separates the liquid in the evaporated gas refrigerant and sucks only the gas refrigerant into the compressor 4. 13 are connected by a refrigerant pipe 14 in this order.

  Further, in the refrigeration cycle 7, the defrosting hot gas bypass pipe 15 and the electromagnetic on-off valves 16 and 17 for directly introducing the hot gas refrigerant discharged from the compressor 4 to the evaporator 12, and the condenser 8 are provided. A condenser fan 18 that blows outside air and an evaporator fan 19 that circulates the air in the freezer 2 to the evaporator 12 are attached. The configuration of the refrigeration cycle 7 is a general one.

  Among the devices constituting the refrigeration cycle 7, the condenser 8, the receiver 9, the electromagnetic opening / closing valves 16 and 17, the condenser fan 18 and the like are disposed in the condenser unit 5, and the supercooler 10, the expansion valve 11, the evaporator 12, and the evaporator fan 19 are disposed in the evaporator unit 6, and the accumulator 13 is disposed in the refrigerant pipe 14 that connects the evaporator unit 6 and the compressor 4.

  Further, the refrigeration cycle 7 includes a discharge refrigerant temperature detection means 20 for detecting the refrigerant temperature Td discharged from the compressor 4, a discharge pressure detection means 21 for detecting the discharge pressure (high pressure) HP of the refrigerant, and a refrigerant. And suction pressure detection means 22 for detecting the suction pressure (low pressure) LP, and the detection values of these detection means 20, 21, 22 are input to the control unit 23. Yes.

  The control unit 23 has a function of determining whether the system is normal or abnormal when the discharged refrigerant temperature Td detected by the discharged refrigerant temperature detecting means 20 is equal to or higher than a specified temperature. If the system is normal, protection of the compressor 4 is temporarily stopped, and after a certain time (for example, 1 minute), the compressor 4 is automatically returned (automatic delay return). If the system is abnormal, the compressor 4 is automatically It has a configuration in which return is prohibited and an abnormal stop (permanent stop) state is established. Below, the logic is demonstrated based on the control flowchart shown in FIG.

  As shown in FIG. 3, when the operation of the transport refrigeration apparatus 3 is started (initial value of abnormal count = 0), the process proceeds to step S1, and the discharge refrigerant temperature Td detected by the discharge refrigerant temperature detection means 20 The allowable maximum temperature (specified temperature) Tmax that can be used by the compressor 4 is compared, and “Td> Tmax” is determined. As a result, if “YES”, the process proceeds to step S2, and if “NO”, the process proceeds to step S3. In step S3, it is determined whether or not a predetermined time Tb (for example, 5 minutes) has elapsed after counting the previous abnormality. If “NO”, the process returns to the start point, and if “YES”, In step S4, after the abnormal count is cleared to 0, the process returns to the start time.

  On the other hand, when the discharged refrigerant temperature Td is equal to or higher than the maximum allowable temperature (specified temperature) Tmax, the process proceeds to step S2 to determine whether the system is normal or abnormal. In step S2, as shown in FIG. 4, the discharge pressure HP and the suction pressure LP of the compressor 4 detected by the discharge pressure detection means 21 and the suction pressure detection means 22 are expressed by a function of a pressure determination formula. Whether the system is in the upper area or the lower area is determined as to whether the system is normal or abnormal. That is, if the operating pressure (refrigerant pressure) of the compressor 4 is within the use restriction range of the compressor 4 (within the broken line in FIG. 4) and is in the region above the pressure determination formula, the high pressure (discharge pressure) Since the HP is high and the low pressure (suction pressure) LP is low, and it can be determined that the discharged refrigerant temperature Td has risen abnormally even though the system is normal, the pressure determination formula is established in this case ( YES), the system is determined to be normal.

  Further, if the operating pressure (refrigerant pressure) of the compressor 4 is in a region below the pressure determination formula, the high pressure (discharge pressure) HP is not increased, and there is an abnormality such as insufficient refrigerant on the system side. Therefore, it can be determined that the discharged refrigerant temperature Td is abnormally increased. In this case, the system is determined to be abnormal because the pressure determination formula is not established (NO).

  If it is determined in step S2 that the system is normal (YES), the process proceeds to step S5, the clutch 4A is turned off to stop the protection of the compressor 4, and then the process proceeds to step S6. In step S6, the time after the protection stop of the compressor 4 is counted, and when a predetermined time Ta (for example, 1 minute) elapses, the clutch 4A is turned on, the compressor 4 is restarted (automatic return), and is transported. The operation of the refrigeration apparatus 3 is resumed.

  If it is determined in step S2 that the system is abnormal (NO), the process proceeds to step S7, a process of adding 1 to the abnormal count is performed, and the process proceeds to step S8. In step S8, it is determined whether or not the abnormal count is N times (for example, 1 time) or less. If “YES”, the process proceeds to step S5, and the compressor 4 is automatically returned after the protection stop as described above. become. On the other hand, when it exceeds N times, it is determined as “NO”, and the compressor 4 is in an abnormally stopped (permanently stopped) state. In this case, operation cannot be resumed without maintenance.

With the above configuration, according to the present embodiment, the following operational effects are obtained.
The cooling operation in the freezer 2 is performed by transmitting power from the traveling engine 1B of the refrigeration vehicle 1 to the compressor 4 via the clutch 4A, and driving the compressor 4 to operate the transport refrigeration apparatus 3. . When the compressor 4 is driven, the refrigerant in the refrigeration cycle 7 is circulated in the cycle. During this time, the high-temperature and high-pressure refrigerant gas compressed by the compressor 4 is sent to the capacitor unit 5 via the refrigerant pipe 14. The condenser 8 radiates heat to the outside air to be condensed and liquefied.

  The refrigerant liquefied by the condenser 8 flows into the evaporator 12 through the expansion valve 11, where it is evaporated by absorbing heat from the air in the freezer 2 sucked into the evaporator unit 6 by the evaporator fan 19. The refrigerant is sucked into the compressor 4 again through the accumulator 13. On the other hand, the air in the freezer 2 circulated through the evaporator 12 is cooled and blown out into the freezer 2 through the evaporator fan 19. Thus, the air in the freezer 2 is circulated between the evaporator unit 6 and the inside of the freezer 2 is cooled to the set temperature.

  During the cooling operation described above, depending on the outside air temperature, the running state of the refrigeration vehicle 1, etc., the temperature inside and outside the freezer 2 and the rotational speed of the compressor 4 become high, and the compressor 4 becomes normal even if the system is normal. The refrigerant temperature Td discharged from the engine may rise abnormally and exceed a specified temperature (allowable maximum temperature) Tmax. The discharged refrigerant temperature Td is detected by the discharged refrigerant temperature detecting means 20, and is input to the control unit 23. When the discharged refrigerant temperature Td is equal to or higher than a specified temperature (allowable maximum temperature) Tmax, the system is operating normally. Determine the abnormality.

  Whether the system is normal or abnormal is that the discharge pressure HP and the suction pressure LP of the compressor 4 detected by the discharge pressure detection means 21 and the suction pressure detection means 22 are the discharge pressure HP and the suction pressure LP as shown in FIG. It is determined based on whether it is in the upper region or the lower region of the pressure determination formula expressed by the function of When the system is determined to be normal and when the system is determined to be abnormal and the abnormal count is N times (one time) or less, the compressor 4 is stopped for a certain period of time (in this embodiment, 1 Minutes), automatic recovery (automatic delay recovery) is performed, and the operation of the transport refrigeration apparatus 3 is resumed.

  On the other hand, when it is determined that the system is abnormal and the abnormal count exceeds N, automatic recovery is prohibited and the compressor 4 is in an abnormally stopped (permanently stopped) state. In this embodiment, when a certain time (5 minutes in the present embodiment) has elapsed since the previous abnormal count, the abnormal count is cleared to 0, so twice within 5 minutes. Unless it is determined that the system is abnormal, the compressor 4 does not fall into an abnormal stop (permanent stop) state.

  Therefore, according to the present embodiment, when the discharged refrigerant temperature is abnormally increased, it is determined whether the discharged refrigerant temperature is high although the system is normal based on the refrigerant pressure or whether the discharged refrigerant temperature is high due to an abnormal system. When the system is normal, the compressor 4 is automatically returned after the protection stop so that the refrigeration operation can be continued, so that the problem that the compressor 4 is in an abnormally stopped state even though the system is normal can be solved. . Therefore, it is possible to prevent incompatibility of the temperature control of the load. Further, when the system is truly abnormal, automatic return is prohibited and the compressor 4 can be brought into an abnormally stopped state, so that damage to the devices constituting the refrigeration apparatus 3 can be prevented.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The present embodiment differs from the first embodiment described above in that the normality or abnormality of the system is determined based on the high pressure HP. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In this embodiment, the control unit 23 shown in FIG. 2 has a function of determining whether the system is normal or abnormal when the high pressure HP detected by the discharge pressure detecting means 21 is equal to or higher than a specified pressure. . If the system is normal, the protection of the compressor 4 is stopped, and after a predetermined time (for example, 1 minute), the compressor 4 is automatically returned (automatic delay return). If the system is abnormal, the compressor 4 is automatically returned. Is set to an abnormal stop (permanent stop) state. FIG. 5 shows a control flowchart thereof.

  In the control flowchart shown in FIG. 5, only steps S11 and S12 are different from those in FIG. 3, and the other steps S13 to S19 are the same as steps S3 to S9, and thus the description thereof is omitted. When the operation of the transport refrigeration apparatus 3 is started, the discharge pressure (high pressure) HP detected by the discharge pressure detection means 21 and the allowable maximum pressure (specified pressure) Pmax that can be used by the compressor 4 are determined in step S11. Are compared, and “HP> Pmax” is determined. As a result, if “YES”, the process proceeds to step S12, and if “NO”, the process proceeds to step S13.

  When the discharge pressure (high pressure) HP exceeds the allowable maximum pressure (specified pressure) Pmax, whether the system is normal or abnormal is determined in step S12. In the present embodiment, as shown in FIG. 6, the suction pressure LP of the compressor 4 detected by the suction pressure detection means 22 and the discharge refrigerant temperature Td detected by the discharge refrigerant temperature detection means 20 are functions thereof. The normality / abnormality of the system is determined based on whether it is in the upper region or the lower region of the temperature determination formula.

  In other words, if the discharge refrigerant temperature Td is within the use restriction range of the compressor 4 (within the broken line in FIG. 6) and is in the region above the temperature determination formula, there is an abnormality such as excessive refrigerant on the system side, and the discharge refrigerant Since it can be determined that the temperature Td has risen abnormally, in this case, the temperature determination formula is not established (NO), and the system is determined to be abnormal. Further, if the discharge refrigerant temperature Td is in a region below the temperature determination formula, it can be determined that the system is normal and the discharge refrigerant temperature Td is within the normal range. In this case, the temperature determination formula is satisfied (YES) The system is determined to be normal.

  According to the above configuration, whether the system is normal or abnormal is indicated by the suction pressure LP of the compressor 4 detected by the suction pressure detection means 22 and the discharge refrigerant temperature Td detected by the discharge refrigerant temperature detection means 20 in FIG. As described above, the determination is made based on whether the temperature is in the upper region or the lower region of the temperature determination formula expressed by the function of the suction pressure LP and the discharge temperature Td. When the system is determined to be normal and when the system is determined to be abnormal and the abnormal count is N times (one time) or less, the compressor 4 is stopped for a certain period of time (in this embodiment, 1 Minutes), automatic return (automatic delay return) is performed, and the operation of the transport refrigeration apparatus 3 is resumed.

  If it is determined that the system is abnormal and the abnormal count exceeds N, automatic recovery is prohibited and the compressor 4 is in an abnormally stopped (permanently stopped) state. Accordingly, the present embodiment can achieve the same effects as those of the first embodiment described above.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
The present embodiment differs from the first and second embodiments described above in that a high pressure abnormality is determined by the outside air temperature. Since other points are the same as those in the first and second embodiments, description thereof will be omitted. In this embodiment, the control unit 23 determines whether the system is normal or abnormal when the high pressure HP detected by the discharge pressure detecting means 21 is equal to or higher than the specified pressure. In the same manner as the second embodiment, the automatic return (automatic delay return) is made, and if it is abnormal, the automatic return of the compressor 4 is prohibited and an abnormal stop (permanent stop) state is set.

  In this embodiment, whether the system is normal or abnormal is determined based on the outside air temperature. For this reason, as shown in FIG. 2, an outside air temperature detecting means 24 for detecting the outside air temperature flowing through the condenser 8 is provided, and the detected value of the outside air temperature detecting means 24 is input to the control unit 23. It is configured.

  Thus, according to the present embodiment, as shown in FIG. 5, in step S11, the discharge pressure (high pressure) HP detected by the discharge pressure detecting means 21 and the allowable maximum pressure that can be used by the compressor 4 ( The specified pressure (Pmax) is compared to determine “HP> Pmax”. As a result, if “YES”, the process proceeds to step S12, and if “NO”, the process proceeds to step S13. In step S <b> 12, whether the system is normal or abnormal is determined based on the outside air temperature detected by the outside air temperature detecting means 24.

  For example, when the refrigerated vehicle 1 is parked in parallel, the exhaust gas of the other vehicle is circulated to the condenser 8 via the condenser fan 18, and the outside air temperature circulated to the condenser 8 temporarily increases abnormally. In this case, even if the system is normal, the high pressure HP may rise abnormally and exceed the specified pressure Pmax. In such a case, whether the system is normal or abnormal can be determined in step S12 based on whether or not the outside air temperature is equal to or higher than a certain temperature.

  That is, when the outside air temperature is equal to or higher than the predetermined temperature and the high pressure HP exceeds the specified pressure (maximum allowable pressure) Pmax, the system can be determined to be normal. The operation of the device 3 is continued. On the other hand, if the outside air temperature is below a certain temperature and the high pressure HP exceeds the specified pressure (allowable maximum pressure) Pmax, it can be determined that the system is abnormal, so automatic recovery is prohibited and the compressor 4 is abnormally stopped (permanently stopped). ) State. Therefore, the present embodiment can provide the same effects as those of the first and second embodiments.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above-described embodiment, the transport refrigeration apparatus 3 in which the condenser unit 5 and the evaporator unit 6 are integrated has been described. However, the condenser unit 5 and the evaporator unit 6 are transport refrigeration apparatuses having a separated configuration. Of course there may be. In this case, the capacitor unit may be mounted on the chassis or the like below the freezer 2.

In the above embodiment, the pressure determination formula, the temperature determination formula, the fixed time Ta, Tb, the number of abnormal counts, etc. are merely examples, and are not limited to these, and can be changed as appropriate. Yes, for example, the pressure determination formula may be replaced with a saturation temperature.
Furthermore, this invention is good also as a structure which combined two or more embodiment of each above-described embodiment.

1 is a schematic side view of a refrigeration vehicle to which a transport refrigeration apparatus according to a first embodiment of the present invention is applied. 1 is a refrigeration cycle diagram of a transport refrigeration apparatus according to a first embodiment of the present invention. It is a control flowchart figure of the transport refrigeration apparatus shown in FIG. It is an image figure at the time of determining the normality / abnormality of the system of the transport refrigeration apparatus shown in FIG. It is a control flowchart figure of the transport refrigeration equipment concerning a 2nd embodiment of the present invention. It is an image figure at the time of determining the system normal / abnormality of the transport refrigeration apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration vehicle 1B Traveling engine 3 Transportation refrigeration apparatus 4 Compressor 20 Discharge refrigerant temperature detection means 21 Discharge pressure (high pressure) detection means 22 Suction pressure (low pressure) detection means 23 Control unit 24 Outside air temperature detection means Td Discharge refrigerant Temperature Tmax Maximum allowable temperature (specified temperature)
HP discharge pressure (high pressure)
LP suction pressure (low pressure)
Pmax allowable maximum pressure (specified pressure)

Claims (4)

A compressor driven by a vehicle running engine, and when the discharge refrigerant temperature of the compressor exceeds a specified temperature, the compressor is automatically returned after being stopped, and a system abnormality occurs when the operation is repeated a predetermined number of times. In a direct-coupled transport refrigeration system that prohibits automatic return of the compressor,
When the discharged refrigerant temperature is equal to or higher than the specified temperature, it is determined whether the system is normal or abnormal based on the detected value of the refrigerant pressure. When the temperature is normal, the compressor is automatically restarted after being stopped. A transport refrigeration apparatus comprising a control unit that prohibits automatic return of the machine.   When the suction pressure and the discharge pressure of the compressor are detected as the refrigerant pressure, and the refrigerant pressure is within the use limit of the compressor and is in the upper region of the determination formula represented by the function of the suction pressure and the discharge pressure Determines that the system is normal and automatically restarts after stopping the compressor, and when the refrigerant pressure is in the lower region of the determination formula, determines that the system is abnormal and prohibits automatic return of the compressor The transport refrigeration apparatus according to claim 1. A compressor driven by a vehicle traveling engine; when the high pressure in the system exceeds a specified pressure, the compressor is automatically returned after being stopped, and if the operation is repeated a predetermined number of times, the system is considered abnormal. In the direct-coupled transport refrigeration apparatus prohibiting the automatic return of the compressor,
When the high pressure is equal to or higher than the specified pressure, it is determined whether the system is normal or abnormal based on detected values of the suction pressure and discharge refrigerant temperature of the compressor, and when normal, the compressor is automatically restarted after being stopped. A transport refrigeration apparatus comprising a control unit that prohibits automatic return of the compressor in the event of an abnormality. A compressor driven by a vehicle traveling engine; when the high pressure in the system exceeds a specified pressure, the compressor is automatically returned after being stopped, and if the operation is repeated a predetermined number of times, the system is considered abnormal. In the direct-coupled transport refrigeration apparatus prohibiting the automatic return of the compressor,
When the high pressure is equal to or higher than the specified pressure, it is determined whether the system is normal or abnormal based on the detected value of the outside air temperature that is circulated through the condenser. In this case, the transport refrigeration apparatus is provided with a control unit that prohibits the automatic return of the compressor.

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