Control method and equipment for refrigerating unit of rail refrigerated vehicle

Abstract

The invention discloses a control method and device for a refrigerating unit of a rail refrigeration vehicle, the refrigerating unit comprises a flash tank, an expansion valve and a condenser, the flash tank is communicated with the condenser through the expansion valve, and the method comprises the steps that the current liquid level in the flash tank is obtained; under the condition that the current liquid level is smaller than or equal to the preset highest liquid level, the current evaporation temperature and the current condensation temperature are determined; according to the current evaporation temperature and the current condensation temperature, the target optimal intermediate pressure of the flash tank is determined, and the target optimal intermediate pressure is the pressure of the flash tank at the current evaporation temperature and the current condensation temperature when the power consumption of the refrigerating unit is the lowest; and controlling the opening degree of the expansion valve according to the target optimal intermediate pressure. According to the technical scheme provided by the invention, the refrigerating unit for transportation with the flash tank can run in the optimal energy-saving state.

Description

Technical Field

[0001] The present application belongs to the technical field of power engineering and engineering thermophysics, and in particular, relates to a control method and device for a refrigeration unit of a rail refrigerated vehicle. Background Art

[0002] At present, the refrigeration systems of rail refrigerated vehicles are mainly divided into two types: one is based on the transport refrigeration unit of Thermo King, which is mainly based on pulley drive; the other is based on the transport refrigeration unit of Carrier, which is mainly an electric drive single-stage circulation system with economizer.

[0003] The control methods of the above two systems are very simple. Among them, the transport refrigeration unit based on Thermo King is mainly controlled by controlling the rotation of the pulley and the linkage device; the transport refrigeration unit based on Carrier is mainly controlled by the expansion valve. For the transport refrigeration unit with a flash tank, it is necessary to adapt specific control logic to make the transport refrigeration unit with a flash tank operate in the best energy-saving state. Summary of the invention

[0004] The embodiments of the present application provide a control method and device for a refrigeration unit of a rail refrigerated vehicle, thereby enabling the transport refrigeration unit with a flash tank to operate in an optimal energy-saving state at least to a certain extent.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, a control method for a refrigeration unit of a rail refrigerated vehicle is provided, wherein the refrigeration unit comprises a flash tank, an expansion valve and a condenser, wherein the flash tank is connected to the condenser via the expansion valve, and the method comprises:

[0007] Obtaining the current liquid level in the flash tank;

[0008] When the current liquid level is less than or equal to a preset maximum liquid level, determining a current evaporation temperature and a current condensation temperature;

[0009] Determine the target optimal intermediate pressure of the flash tank according to the current evaporation temperature and the current condensation temperature, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature;

[0010] The opening degree of the expansion valve is controlled according to the target optimal intermediate pressure.

[0011] In some embodiments, determining the target optimal intermediate pressure of the flash tank according to the current evaporation temperature and the current condensation temperature includes:

[0012] Searching for the optimal intermediate pressure corresponding to the current evaporation temperature and the current condensation temperature in a preset mapping table, wherein the preset mapping table is used to characterize the corresponding relationship between the evaporation temperature and the condensation temperature and the optimal intermediate pressure;

[0013] The found optimal intermediate pressure is determined as the target optimal intermediate pressure of the flash tank.

[0014] In some embodiments, controlling the opening of the expansion valve according to the target optimal intermediate pressure includes:

[0015] determining a current intermediate pressure according to the current evaporation temperature and the current condensation temperature;

[0016] determining a target opening of the expansion valve based on the current intermediate pressure, the target optimal intermediate pressure and a PID algorithm;

[0017] The opening degree of the expansion valve is controlled to be the target opening degree.

[0018] In some embodiments, determining the current evaporation temperature and the current condensation temperature includes:

[0019] Get the current evaporation pressure and the current condensation pressure;

[0020] determining the current evaporation temperature according to the current evaporation pressure;

[0021] The current condensing temperature is determined according to the current condensing pressure.

[0022] In some embodiments, the control method of the refrigeration unit of the rail refrigerated vehicle further includes:

[0023] When the current liquid level is greater than the preset maximum liquid level, the opening of the expansion valve is controlled according to the current liquid level and the preset maximum liquid level.

[0024] In some embodiments, controlling the opening of the expansion valve according to the current liquid level and the preset maximum liquid level includes:

[0025] Determining a target opening of the expansion valve based on the current liquid level, the preset maximum liquid level and a PID algorithm;

[0026] The opening degree of the expansion valve is controlled to be the target opening degree.

[0027] In some embodiments, the control method of the refrigeration unit of the rail refrigerated vehicle further includes:

[0028] The preset maximum liquid level is determined according to the position of the steam outlet of the flash tank.

[0029] According to a second aspect of an embodiment of the present application, a control device for a refrigeration unit of a rail refrigerated vehicle is provided, comprising a processor and a memory, wherein the memory stores computer program instructions that can be executed by the processor, and when the processor executes the computer program instructions, the steps of the method described in any one of the first aspects above are implemented.

[0030] According to a third aspect of an embodiment of the present application, a computer-readable storage medium is provided, in which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor is prompted to implement the steps of the method described in any one of the first aspects above.

[0031] According to a fourth aspect of an embodiment of the present application, a computer program product is provided, including a computer program. When the computer program product is executed by a processor, it prompts the processor to implement the steps of the method described in any one of the first aspects above.

[0032] In the present application, the current liquid level in the flash tank is obtained; when the current liquid level is less than or equal to the preset maximum liquid level, the current evaporation temperature and the current condensation temperature are determined; according to the current evaporation temperature and the current condensation temperature, the target optimal intermediate pressure of the flash tank is determined, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature; according to the target optimal intermediate pressure, the opening of the expansion valve is controlled. The technical solution provided by the present application enables the transport refrigeration unit with a flash tank to operate in the best energy-saving state.

[0033] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0035] Figure 1 A schematic diagram showing a control system of a refrigeration unit of a rail refrigerated vehicle in the related art;

[0036] Figure 2 A schematic flow chart of a control method for a refrigeration unit of a rail refrigerated vehicle in one embodiment is shown;

[0037] Figure 3 Shows Figure 2 Schematic diagram of the distribution of the optimal intermediate pressure as the evaporation temperature and condensation temperature change;

[0038] Figure 4 A schematic flow chart of a control method for a refrigeration unit of a rail refrigerated vehicle in another embodiment is shown;

[0039] Figure 5 Shows Figure 4 Schematic diagram of data flow in the figure;

[0040] Figure 6 A block diagram of a control device for a refrigeration unit of a rail refrigerated vehicle in one embodiment is shown;

[0041] Figure 7 A schematic structural diagram of a control device for a refrigeration unit of a rail refrigerated vehicle in one embodiment is shown. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0044] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0045] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0046] In order to make those skilled in the art better understand the present application, firstly, Figure 1 The application scenarios involved in this application are briefly described.

[0047] Figure 1 FIG. 1 is a schematic diagram showing a control system of a refrigeration unit of a rail refrigerated vehicle in the related art. Figure 1 As shown, the refrigeration unit of the rail refrigerated vehicle includes a flash tank, an expansion valve 1, a condenser, a heater, a solenoid valve, a compressor, an expansion valve 2 and an evaporator. The intermediate pressure is a unique operating pressure of the air replenishment and enthalpy increase system, which refers to the pressure after the expansion valve 1 is throttled, that is, the pressure of the flash tank. At present, the commonly used control method for the intermediate pressure is to set a heater in the air replenishment circuit between the flash tank and the compressor, and to heat the saturated gas in the air replenishment circuit so that it has a certain degree of superheat. The opening and closing of the expansion valve 1 is controlled by the superheat, thereby realizing the control of the intermediate pressure. The above control method will increase the energy consumption of the refrigeration unit due to the electric power of the heater, and the addition of the heater will increase the temperature of the refrigerant in the air replenishment circuit, resulting in a high temperature of the refrigerant after mixing with the low-pressure fluid, which will eventually lead to an increase in the exhaust temperature of the compressor, which will have a certain impact on the safety and stability of the refrigeration unit.

[0048] In the embodiment of the present application, the current liquid level in the flash tank is obtained; when the current liquid level is less than or equal to the preset maximum liquid level, the current evaporation temperature and the current condensation temperature are determined; according to the current evaporation temperature and the current condensation temperature, the target optimal intermediate pressure of the flash tank is determined, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature; according to the target optimal intermediate pressure, the opening of the expansion valve between the condenser and the flash tank is controlled. This control method does not require the addition of a heater to the refrigeration unit, thus avoiding the influence of the heater on the safety and stability of the refrigeration unit, and the control scheme can keep the power consumption of the transport refrigeration unit with a flash tank to the lowest and keep it running in the best energy-saving state.

[0049] Figure 2 FIG. 1 is a flow chart showing a control method for a refrigeration unit of a rail refrigerated vehicle in one embodiment. Figure 2 As shown, a control method for a refrigeration unit of a rail refrigerated vehicle is provided, and the method may include the following steps 201 to 204.

[0050] In step 201, the current liquid level in the flash tank is obtained.

[0051] Among them, the flash tank can be transformed from a liquid storage tank. By setting a liquid level sensor in the flash tank, the liquid level in the flash tank can be monitored in real time to obtain the current liquid level.

[0052] In step 202, when the current liquid level is less than or equal to the preset maximum liquid level, the current evaporation temperature and the current condensation temperature are determined.

[0053] In order to prevent the compressor from inflowing liquid, the current liquid level in the flash tank cannot be too high, so a preset maximum liquid level needs to be set. In some embodiments, the preset maximum liquid level can be determined according to the position of the steam outlet of the flash tank.

[0054] When the flash tank is initially charged with refrigerant, the liquid level in the flash tank should be maintained at about 30% of the total height of the flash tank, and the preset maximum liquid level in the flash tank can be 70% of the total height of the flash tank. Studies have shown that the maximum limit of the liquid in the flash tank is 60% to 70% of the total height of the flash tank, which is related to the position of the steam outlet of the flash tank. The steam outlet of the flash tank selected by the embodiment of the present application is located at the top of the flash tank, and the distance from the bottom accounts for about 90% of the total height of the flash tank. Therefore, setting 70% of the total height of the flash tank as the preset maximum liquid level can expand the adjustable range of the intermediate pressure as much as possible while ensuring that the compressor does not enter the liquid.

[0055] In the embodiment of the present application, considering that the current liquid level may be less than or equal to the preset maximum liquid level, or may be greater than the preset maximum liquid level, when the current liquid level is less than or equal to the preset maximum liquid level, the refrigeration unit is in normal working condition, and its power consumption needs to be considered at this time to keep it in energy-saving operation; and when the current liquid level is greater than the preset maximum liquid level, the compressor in the refrigeration unit is prone to liquid inflow, and at this time, the liquid level in the flash tank needs to be lowered as soon as possible to ensure the safe operation of the refrigeration unit. Therefore, different control strategies need to be adopted for these two situations.

[0056] When the current liquid level is less than or equal to the preset maximum liquid level, the optimal intermediate pressure control strategy is preferentially adopted, that is, according to the current evaporation temperature and the current condensation temperature, the opening of the expansion valve between the flash tank and the condenser is adjusted by utilizing the relationship between the optimal intermediate pressure and the evaporation temperature and the condensation temperature, so that the pressure in the flash tank is always maintained at the optimal intermediate pressure.

[0057] In some embodiments, the current evaporation pressure and the current condensation pressure may be acquired; the current evaporation temperature may be determined based on the current evaporation pressure; and the current condensation temperature may be determined based on the current condensation pressure.

[0058] It is understandable that, through the pressure sensor in the refrigeration unit, the evaporation pressure and condensation pressure in the pipeline can be detected in real time to obtain the current evaporation pressure and the current condensation pressure, and then the current evaporation pressure is substituted into the formula to calculate the current evaporation temperature, and the current condensation pressure is substituted into the formula to calculate the current condensation temperature. The specific formula is not limited in the embodiments of the present application.

[0059] The current evaporation temperature and the current condensation temperature obtained by converting the current evaporation pressure and the current condensation pressure have higher accuracy than the current evaporation temperature and the current condensation temperature directly detected by the temperature sensor.

[0060] In step 203, the target optimal intermediate pressure of the flash tank is determined according to the current evaporation temperature and the current condensation temperature, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature.

[0061] In some embodiments, the optimal intermediate pressure corresponding to the current evaporation temperature and the current condensation temperature can be found in a preset mapping table, wherein the preset mapping table is used to characterize the correspondence between the evaporation temperature and the condensation temperature and the optimal intermediate pressure; the found optimal intermediate pressure is determined as the target optimal intermediate pressure of the flash tank.

[0062] Research shows that the optimal intermediate pressure has nothing to do with the speed of the compressor. Therefore, in the implementation process, the optimal intermediate pressure at the rated speed of 3240rpm can be calculated, and the calculation results are shown in Table 1:

[0063] Table 1

[0064]

[0065] The data in Table 1 are input into the PLC program. The current evaporation pressure and the current condensation pressure measured at the pressure measuring point are converted into the current evaporation temperature and the current condensation temperature. The optimal intermediate pressure corresponding to the current evaporation temperature and the current condensation temperature is then obtained by looking up the table, and is used as the target optimal intermediate pressure.

[0066] Figure 3 Shows Figure 2 Schematic diagram of the distribution of the optimal intermediate pressure as the evaporation temperature and condensation temperature change. Figure 3 As shown in Figure 1, with the increase of condensing temperature and evaporating temperature, the optimal intermediate pressure shows a gradual upward trend. This may be because the increase of condensing temperature leads to a higher condensing pressure, and the overall pressure of the refrigeration unit increases, which leads to an increase in the optimal intermediate pressure.

[0067] In step 204 , the opening degree of the expansion valve is controlled according to the target optimal intermediate pressure.

[0068] Among them, controlling the opening of the expansion valve refers to controlling the opening of the expansion valve between the condenser and the flash tank.

[0069] In some embodiments, the current intermediate pressure can be determined based on the current evaporating temperature and the current condensing temperature; the target opening of the expansion valve can be determined based on the current intermediate pressure, the target optimal intermediate pressure and the PID algorithm; and the opening of the expansion valve can be controlled to be the target opening.

[0070] During the implementation process, the deviation between the current intermediate pressure and the target optimal intermediate pressure can be input into the PID controller, and the PID controller outputs the target opening of the expansion valve. By controlling the opening of the expansion valve to the target opening, the pressure in the flash tank can always be maintained at the optimal intermediate pressure.

[0071] The embodiment of the present application obtains the current liquid level in the flash tank; when the current liquid level is less than or equal to the preset maximum liquid level, determines the current evaporation temperature and the current condensation temperature; determines the target optimal intermediate pressure of the flash tank according to the current evaporation temperature and the current condensation temperature, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature; controls the opening of the expansion valve according to the target optimal intermediate pressure. The technical solution provided by the present application enables the transport refrigeration unit with a flash tank to operate in the best energy-saving state.

[0072] Figure 4 FIG. 2 is a flow chart showing a control method for a refrigeration unit of a rail refrigerated vehicle in another embodiment. Figure 4 As shown, in some embodiments, the control method of the refrigeration unit of the rail refrigerated vehicle may further include step 401 in addition to the above steps 201 to 204: when the current liquid level is greater than the preset maximum liquid level, controlling the opening of the expansion valve according to the current liquid level and the preset maximum liquid level.

[0073] It is understandable that when the current liquid level is greater than the preset maximum liquid level, the liquid level control strategy is preferentially adopted, that is, the opening of the expansion valve between the flash tank and the condenser is adjusted according to the current liquid level in the flash tank, so that the liquid level in the flash tank is reduced to the preset maximum liquid level.

[0074] In some embodiments, the target opening of the expansion valve may be determined based on the current liquid level, a preset maximum liquid level, and a PID algorithm; and the opening of the expansion valve may be controlled to be the target opening.

[0075] In the implementation process, the deviation between the current liquid level and the preset maximum liquid level can be input into the PID controller, and the PID controller outputs the target opening of the expansion valve. By controlling the opening of the expansion valve to the target opening, the liquid level in the flash tank can be reduced to the preset maximum liquid level.

[0076] Figure 5 Shows Figure 4 Schematic diagram of the data flow in . Figure 5As shown, the pressure in the flash tank can be controlled by a control method combining the optimal intermediate pressure and liquid level control. When the current liquid level is greater than the preset maximum liquid level, the opening of the expansion valve is controlled by PID to adjust the amount of liquid in the flash tank to reduce it to the preset maximum liquid level according to the deviation between the current liquid level in the flash tank and the preset maximum liquid level; when the current liquid level is less than or equal to the preset maximum liquid level, the current intermediate pressure and the target optimal intermediate pressure are determined according to the current evaporation temperature and the current condensation temperature, and the pressure in the flash tank is adjusted by PID to control the opening of the expansion valve according to the deviation between the current intermediate pressure and the target optimal intermediate pressure.

[0077] It should be noted that, because the energy efficiency ratio of the refrigeration unit increases first and then decreases with the increase of the intermediate pressure at different evaporation temperatures and condensation temperatures, there is an optimal intermediate pressure that makes the performance of the refrigeration unit optimal. If the liquid level control is still used when the current liquid level is less than or equal to the preset maximum liquid level, it is impossible to determine whether the refrigeration unit is operating at the optimal intermediate pressure, which will lead to low performance of the refrigeration unit.

[0078] The embodiment of the present application selectively uses the optimal intermediate pressure control or liquid level control according to the current liquid level, which not only avoids liquid intrusion into the compressor and ensures the safe operation of the refrigeration unit, but also ensures that the refrigeration unit operates in the best energy-saving state.

[0079] The following describes an embodiment of the device of the present application, which can be used to execute the control method of the refrigeration unit of the rail refrigerated vehicle in the above embodiment of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the control method of the refrigeration unit of the rail refrigerated vehicle in the above embodiment of the present application.

[0080] Figure 6 FIG. 1 is a block diagram of a control device for a refrigeration unit of a rail refrigerated vehicle in one embodiment. Figure 6 As shown, the control device of the refrigeration unit of the rail refrigerated vehicle of the embodiment of the present application includes: a data acquisition module 601 and an intermediate pressure control module 602, wherein the data acquisition module 601 is used to obtain the current liquid level in the flash tank; the intermediate pressure control module 602 is used to determine the current evaporation temperature and the current condensation temperature when the current liquid level is less than or equal to the preset maximum liquid level; according to the current evaporation temperature and the current condensation temperature, the target optimal intermediate pressure of the flash tank is determined, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature; according to the target optimal intermediate pressure, the opening of the expansion valve is controlled.

[0081] In some embodiments of the present application, based on the aforementioned scheme, the intermediate pressure control module 602 is also used to search for the optimal intermediate pressure corresponding to the current evaporation temperature and the current condensation temperature in a preset mapping table, wherein the preset mapping table is used to characterize the correspondence between the evaporation temperature and the condensation temperature and the optimal intermediate pressure; and the found optimal intermediate pressure is determined as the target optimal intermediate pressure of the flash tank.

[0082] In some embodiments of the present application, based on the aforementioned scheme, the intermediate pressure control module 602 is also used to determine the current intermediate pressure according to the current evaporating temperature and the current condensing temperature; determine the target opening of the expansion valve based on the current intermediate pressure, the target optimal intermediate pressure and the PID algorithm; and control the opening of the expansion valve to be the target opening.

[0083] In some embodiments of the present application, based on the aforementioned scheme, the intermediate pressure control module 602 is also used to obtain the current evaporation pressure and the current condensation pressure; determine the current evaporation temperature according to the current evaporation pressure; and determine the current condensation temperature according to the current condensation pressure.

[0084] In some embodiments of the present application, based on the above solution, the intermediate pressure control module 602 is further used to determine a preset maximum liquid level according to the position of the steam outlet of the flash tank.

[0085] In some embodiments of the present application, based on the aforementioned scheme, the control device of the refrigeration unit of the rail refrigerated vehicle may also include a liquid level control module 603, which is used to control the opening of the expansion valve according to the current liquid level and the preset maximum liquid level when the current liquid level is greater than the preset maximum liquid level.

[0086] In some embodiments of the present application, based on the aforementioned scheme, the liquid level control module 603 is also used to determine the target opening of the expansion valve based on the current liquid level, the preset maximum liquid level and the PID algorithm; and control the opening of the expansion valve to be the target opening.

[0087] Based on the same inventive concept, the present application embodiment also provides a control device for a refrigeration unit of a rail refrigerated vehicle, referring to Figure 7 , showing a schematic diagram of the structure of the control device of the refrigeration unit of the rail refrigerated vehicle in an embodiment of the present application, the control device of the refrigeration unit of the rail refrigerated vehicle includes one or more memories 704, one or more processors 702 and at least one computer program (computer program instruction) stored in the memory 704 and executable on the processor 702, and the processor 702 implements the method described above when executing the computer program.

[0088] Among them, Figure 7In the embodiment of the present invention, a bus architecture (represented by bus 700) is shown, which may include any number of interconnected buses and bridges, and bus 700 links various circuits including one or more processors represented by processor 702 and memory represented by memory 704. Bus 700 may also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. Bus interface 705 provides an interface between bus 700 and receiver 701 and transmitter 703. Receiver 701 and transmitter 703 may be the same element, namely a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 702 is responsible for managing bus 700 and general processing, while memory 704 may be used to store data used by processor 702 when performing operations.

[0089] Based on the same inventive concept, an embodiment of the present application provides a computer-readable storage medium, in which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor is prompted to implement the steps of the method as described above.

[0090] Based on the same inventive concept, an embodiment of the present application provides a computer program product, including a computer program. When the computer program product is executed by a processor, it prompts the processor to implement the steps of the method as described above.

[0091] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0092] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0093] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0094] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly or all or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store computer program instructions.

[0095] The above description is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A control method for a refrigeration unit of a rail refrigerated vehicle, characterized in that: The refrigeration unit comprises a flash tank, an expansion valve and a condenser, wherein the flash tank is connected to the condenser via the expansion valve, and the method comprises: Obtaining the current liquid level in the flash tank; When the current liquid level is less than or equal to a preset maximum liquid level, determining a current evaporation temperature and a current condensation temperature; Determine the target optimal intermediate pressure of the flash tank according to the current evaporation temperature and the current condensation temperature, wherein the target optimal intermediate pressure is the pressure of the flash tank when the power consumption of the refrigeration unit is the lowest at the current evaporation temperature and the current condensation temperature; The opening degree of the expansion valve is controlled according to the target optimal intermediate pressure.

2. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 1, characterized in that: The step of determining the target optimal intermediate pressure of the flash tank according to the current evaporation temperature and the current condensation temperature comprises: Searching for the optimal intermediate pressure corresponding to the current evaporation temperature and the current condensation temperature in a preset mapping table, wherein the preset mapping table is used to characterize the corresponding relationship between the evaporation temperature and the condensation temperature and the optimal intermediate pressure; The found optimal intermediate pressure is determined as the target optimal intermediate pressure of the flash tank.

3. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 1, characterized in that: The step of controlling the opening of the expansion valve according to the target optimal intermediate pressure comprises: determining a current intermediate pressure according to the current evaporation temperature and the current condensation temperature; determining a target opening of the expansion valve based on the current intermediate pressure, the target optimal intermediate pressure and a PID algorithm; The opening degree of the expansion valve is controlled to be the target opening degree.

4. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 1, characterized in that: The determining of the current evaporation temperature and the current condensation temperature comprises: Get the current evaporation pressure and the current condensation pressure; determining the current evaporation temperature according to the current evaporation pressure; The current condensing temperature is determined according to the current condensing pressure.

5. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 1, characterized in that: Also includes: When the current liquid level is greater than the preset maximum liquid level, the opening of the expansion valve is controlled according to the current liquid level and the preset maximum liquid level.

6. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 5, characterized in that: The controlling the opening of the expansion valve according to the current liquid level and the preset maximum liquid level comprises: Determining a target opening of the expansion valve based on the current liquid level, the preset maximum liquid level and a PID algorithm; The opening degree of the expansion valve is controlled to be the target opening degree.

7. The control method of the refrigeration unit of the rail refrigerated vehicle according to claim 1, characterized in that: Also includes: The preset maximum liquid level is determined according to the position of the steam outlet of the flash tank.

8. A control device for a refrigeration unit of a rail refrigerated vehicle, comprising a processor and a memory, characterized in that: The memory stores computer program instructions that can be executed by the processor, and when the processor executes the computer program instructions, the steps of the method according to any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, which, when executed by a processor, prompt the processor to implement the steps of the method according to any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that When the computer program product is executed by a processor, the processor is prompted to implement the steps of the method according to any one of claims 1 to 7.

Images