Refrigerant loop, method of operating a refrigerant loop, and heating system

Abstract

The refrigerant loop (102) includes a main loop (104) and a bypass loop (106). The main loop includes at least one heat exchanger (110), a first expansion valve (112) configured to control the flow of refrigerant through the refrigerant loop, a compressor, and a sensor (116) for detecting at least one of the following from the compressor (130): discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time. The bypass loop includes a second expansion valve (114) configured to control the flow of refrigerant through the refrigerant loop. A controller (122) controls the opening and closing of the first and second expansion valves based on the detected discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time.

Description

Cross - reference to related applications

[0001] This disclosure is based on and incorporates by reference U.S. Provisional Patent Application No. 63 / 534,682, filed on August 25, 2023, U.S. Provisional Patent Application No. 63 / 499,931, filed on May 3, 2023, and U.S. Non - Provisional Patent Application No. 18 / 380,010, filed on October 13, 2023, the contents of which are incorporated by reference in their entirety.

Technical Field

[0002] This specification generally relates to refrigerant loops for heating and cooling, and more particularly to a refrigerant loop for heating a vehicle at startup.

Background Art

[0003] Vehicles are equipped with a heating system that provides heating and / or cooling to various parts of the vehicle, including the passenger compartment. The heating system takes time to heat in order to supply heat to various parts of the vehicle, and it takes even more time when the ambient temperature drops. In the case of electric vehicles, it is desirable to heat for a predetermined time before unplugging and / or before driving in order to optimize the driving range and performance of the vehicle. Therefore, an improved heating system that reduces the time required for heating is needed.

Summary of the Invention

[0004] According to a first embodiment, the refrigerant loop includes a main loop which includes at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, a sensor that detects at least one of the following from the compressor: discharge superheat (SH), discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time, a bypass loop which includes a second expansion valve configured to control the flow of refrigerant through the refrigerant loop, and a controller that controls the opening and closing of the first and second expansion valves based on the detected discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time.

[0005] According to a second embodiment, a method for operating a refrigerant loop includes defining an initial opening of an expansion valve, that the initial opening is substantially open or substantially closed, determining the characteristics of the discharge side of a compressor, determining whether the characteristics of the discharge side of the compressor are outside a predetermined range of thresholds, and changing the magnitude of the opening of the expansion valve in response to the characteristics of the discharge side of the compressor being outside a predetermined range of thresholds.

[0006] According to a third aspect, a method for operating a refrigerant loop includes determining the characteristics of the discharge side of a compressor, controlling an expansion valve using a first method, the first method including control logic based on the characteristics of the discharge side of the compressor, determining the characteristics of the suction side of a compressor, and controlling an expansion valve using a second method, the second method including control logic based on the characteristics of the suction side of a compressor, in response that the characteristics of the suction side of the compressor meet a predetermined criterion.

[0007] According to a fourth aspect, a method for operating a refrigerant loop includes detecting a state related to the operating environment of the refrigerant loop; defining, based on the detected state, at least one operating mode of a first expansion valve and a second expansion valve, and related parameters, the related parameters including a first initial opening of the first expansion valve, wherein the initial opening of the first expansion valve is substantially open or substantially closed, and an initial opening of the second expansion valve, wherein the initial opening of the expansion valve is substantially open or substantially closed; setting the first expansion valve to a first initial opening and the second expansion valve to a second initial opening; determining the characteristics of the discharge side of the compressor; controlling the opening of at least one of the first expansion valve and the second expansion valve based on the characteristics of the discharge side of the compressor; determining the characteristics of the suction side of the compressor; and controlling the opening of at least one of the first expansion valve and the second expansion valve based on the suction-discharge characteristics in response to the suction-side characteristics of the compressor satisfying predetermined characteristics.

[0008] According to a first embodiment, the refrigerant loop comprises a main loop which includes at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, a first sensor configured to output characteristics of the suction side of the compressor, a second sensor configured to output characteristics of the discharge side of the compressor, a bypass loop which includes a second expansion valve configured to control the flow of refrigerant through the refrigerant loop, and a controller configured as follows: In response to conditions relating to the operating environment of the refrigerant loop, the opening and closing of at least one of the first expansion valve and the second expansion valve is controlled using a first method, the first method including control logic based on the characteristics of the discharge side of the compressor, and in response to the characteristics of the suction side of the compressor meeting a predetermined criterion, switching control of the opening and closing of at least one of the first expansion valve and the second expansion valve is performed using a second method, the second method including control logic based on the characteristics of the suction side of the compressor. [Brief explanation of the drawing]

[0009] The above-mentioned objectives, features, and advantages of the present invention, as well as other objectives, features, and advantages, will become more apparent from the following detailed description with reference to the accompanying drawings.

[0010] [Figure 1] Figure 1 schematically shows a vehicle heating system according to one or more embodiments disclosed herein. [Figure 2] Figure 2 schematically shows a control system for controlling the heating system of Figure 1, according to one or more embodiments disclosed herein. [Figure 3] Figure 3 schematically shows a flowchart of a method for operating the heating system of Figure 1 according to one or more embodiments disclosed herein. [Figure 4] Figure 4 schematically shows a flowchart of a method for operating the heating system of Figure 1 according to one or more embodiments disclosed herein. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure are described below. However, it should be understood that the disclosed embodiments are merely examples and can take various alternative forms as shown and suggested in other embodiments. The figures are not necessarily to scale, and some features may be exaggerated or reduced to show details of certain components. Accordingly, certain structural and functional details disclosed in this specification should not be constrained, but rather should be interpreted simply as representative grounds for teaching those skilled in the art that the embodiments can be used in various ways. As those skilled in the art will understand, various features illustrated and described with reference to any of the figures can be combined with features shown in one or more other figures to produce embodiments that are not explicitly illustrated or described. Combinations of illustrated features provide representative embodiments for typical uses. However, various combinations of features and modifications that are consistent with the teachings of this disclosure may be desired for specific uses or implementations.

[0012] The singular and plural terms used in this specification should be understood to refer to both singular and plural objects unless the context clearly indicates otherwise. For example, "processor" programmed to perform various functions may refer to a single processor programmed to perform all functions, or to multiple processors collectively programmed to perform each of the various functions.

[0013] Embodiments disclosed herein relate to a heating system that includes a control system that controls the flow of refrigerant through a compressor by controlling the opening and closing of at least one expansion valve. Suitable types of refrigerant may be any, but are not limited to, R290, 1234yf, R134a, R152, etc. The flow of refrigerant is controlled to increase the heating rate of the heating system, i.e., the heat transfer capacity of the heating system. The heating system can be implemented in vehicles such as automobiles, SUVs, trucks, aircraft (airplanes, helicopters, etc.), buses, boats, etc., and once the vehicle is started, the heating system can transfer heat to other parts of the vehicle in a shorter time than a conventional heating system without the disclosed control system. Additional details of the heating system are described in relation to Figures 1, 2, and 3.

[0014] Referring to Figure 1, a heating system 100 according to one or more embodiments disclosed herein is shown. The heating system 100 typically includes a refrigerant loop 102, which includes a main loop 104 and a bypass loop 106. In such embodiments, the heating system 100 may be, for example, a heat pump for an electric vehicle. The heating system 100 may include additional loops, such as a coolant loop 108. The coolant loop 108 is connected to the refrigerant loop 102 by a heat exchanger, enabling heat exchange between the refrigerant loop 102 and the coolant loop 108. The coolant loop 108 may include a heat pump, HVAC, or other heating device 109 and a first compressor or coolant pump 111. These regulate the temperature in the coolant loop 108, which transfers heat to the refrigerant loop 102 and distributes heat through the heating device 109. The refrigerant loop 102 may include at least one heat exchanger 110, a first expansion valve 112, a second expansion valve 114, a second compressor 130, a first sensor 116, a second sensor 118, an external sensor 120, and a controller 122. Briefly referring to Figure 2, the controller 122 is communicatively coupled to the first sensor 116, the second sensor 118, the external sensor 120, the first expansion valve 112, and the second expansion valve 114, enabling the exchange of signals between them.

[0015] Returning to Figure 1, at least one heat exchanger 110 of the main loop 104 may include a first heat exchanger 124 positioned between one of the sensors 116, 118 and the first expansion valve 112, and a second heat exchanger 126 positioned between the first expansion valve 112 and the second compressor 130. The first heat exchanger 124 may exchange heat between the refrigerant loop 102 and the coolant loop 108. The second heat exchanger 126 may exchange heat between the refrigerant loop 102 and the other loops. The first expansion valve 112 may be configured to control the flow of refrigerant through the main loop 104 of the refrigerant loop 102. The second expansion valve 114 may be configured to control the flow of refrigerant through the bypass loop 106 of the refrigerant loop 102. The second expansion valve 114 may have a larger opening than the opening of the first expansion valve 112. The magnitude of the opening of the expansion valves 112, 114 is the cross-sectional area of ​​the valve through which the refrigerant flows perpendicular to the fluid flow through the refrigerant loop. Increasing the magnitude of the opening increases the refrigerant flow, and decreasing the magnitude of the opening decreases the refrigerant flow. The magnitude of the opening of each expansion valve 112, 114 can be reduced or increased. For example, the magnitude of the opening can be reduced from the maximum opening that allows the maximum fluid flow through the expansion valve. Each expansion valve 112, 114 is openable and closable between a fully open position that allows the maximum fluid flow through the valve without reducing the fluid flow through the loop, and a fully closed position that completely restricts the fluid flow through the expansion valves 112, 114. The position of each expansion valve 112, 114 can be moved to any position between a substantially open position and a substantially closed position. In the substantially open position, a flow rate between 50% and 100% of the maximum fluid flow rate through the expansion valves 112, 114 is permitted, and in the substantially closed position, a flow rate between 0% and 30% of the maximum fluid flow rate is permitted. For example, a substantially closed position may be 5% of the maximum fluid flow rate through the expansion valve. In some embodiments, a substantially closed position may exclude 0%. Each expansion valve 112, 114 may be controlled by the controller 122 using the same or separate control signals from the controller 122, based on coupled logic, proportional logic, or independent logic.

[0016] The first sensor 116 may be located on the discharge side of the second compressor 130. The first sensor 116 may be configured to detect at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from the second compressor 130. The second sensor 118 may be located on the suction side of the second compressor 130 and is configured to detect at least one of the suction superheat, suction gas-liquid ratio, suction pressure, and suction temperature of the second compressor 130, and the controller 122 determines whether the detected value exceeds a second threshold. The second threshold may be, for example, 0°C. As used in this specification, passing a threshold may include being greater than or equal to the threshold, or being less than or equal to the threshold. Exceeding a threshold may include going from being greater than or equal to the threshold to being less than or equal to the threshold, or vice versa. In embodiments, the controller 122 may determine whether the detected value is outside a predetermined range of the threshold. A given range may have a lower limit that is smaller than the upper limit, and the threshold may be equal to the lower limit, equal to the upper limit, or located between the lower limit and the upper limit.

[0017] The first expansion valve 112 and the second expansion valve 114 may each have an opening whose magnitude is controlled based on the detected discharge superheat, discharge pressure, discharge temperature, intake superheat, intake gas-liquid ratio, intake pressure, and / or intake temperature. The external sensor 120 may be configured to detect ambient temperature. Ambient temperature may be the temperature of the air inside or around the vehicle, such as the passenger compartment, engine compartment, or outside temperature of the vehicle. The first expansion valve 112 and the second expansion valve 114 may be additionally or alternatively controlled based on the detected ambient temperature. In some embodiments, either the first sensor 116 and the second sensor 118 may be configured to detect the speed of the compressor, such as rotational speed.

[0018] The controller 122 is configured to control the opening and closing of the first expansion valve 112 based on at least one of the detected discharge superheat SH, discharge pressure, and discharge temperature, and when at least one of the detected discharge superheat, discharge pressure, and discharge temperature exceeds a first threshold, the controller 122 changes the magnitude of the opening of the first expansion valve 112. The controller 122 may include an actuator configured to open and / or close the connected valve, as disclosed in this specification, and a processor that signals the actuator to act based on a sensed state or threshold.

[0019] In this disclosure, the terms “controller” and “system” refer to, parts of, or include, hardware processors (which may be shared, dedicated, or grouped) for executing code, and hardware memory (which may be shared, dedicated, or grouped) for storing code executed by the hardware processors. The code is configured to provide the functions and features of the controllers and systems described in this specification. In one example, the controller may include processors, memory, and non-volatile storage. The processor may include one or more devices selected from microprocessors, microcontrollers, digital signal processors, microcomputers, central processing units, field-programmable gate arrays, programmable logic devices, state machines, logic circuits, analog circuits, digital circuits, or other devices that manipulate signals (analog or digital) based on computer-executable instructions residing in memory. Memory may include, but is not limited to, a single memory device or multiple memory devices, including random access memory ("RAM"), volatile memory, non-volatile memory, static random access memory ("SRAM"), dynamic random access memory ("DRAM"), flash memory, cache memory, or other devices capable of storing information. Non-volatile storage may include one or more persistent data storage devices, such as hard drives, optical drives, tape drives, non-volatile solid-state devices, or other devices capable of permanently storing information. A processor may be configured to load and execute computer executable instructions into memory that embody one or more software programs residing in non-volatile storage.Programs residing in non-volatile storage may include or be part of an operating system or application, and may be compiled or interpreted from computer programs written using a variety of programming languages ​​and technologies, including Java, C, C++, C#, Objective-C, Fortran, Pascal, JavaScript, Python, Perl, and PL / SQL, either alone or in combination. The computer executable instructions of a program, when executed by the processor, may be configured, for example, to cause an actuator to output signals to the processor to open or close each valve.

[0020] The subject matter and implementations of operation described in this specification may be implemented in digital electronic circuits or computer software embodied on tangible media, firmware, or hardware, including the structures disclosed in this specification, their structural equivalents, or one or more combinations thereof. Implementations of the subject matter described in this specification may be implemented as one or more computer programs embodied on tangible media, for example, as one or more modules of computer program instructions executed by a data processing device or encoded on one or more computer storage media to control its operation. Computer storage media may be computer-readable storage devices, computer-readable storage boards, random or serial access memory arrays or devices, or one or more combinations thereof, or contained therein. Computer storage media may be one or more separate components or media (such as multiple CDs, disks, or other storage devices), or contained within one or more separate components or media. Computer storage media may be tangible and non-temporary.

[0021] Computer programs (also called programs, software, software applications, scripts, or code) can be written in any form of programming language, including compiled languages, interpreted languages, declarative languages, and procedural languages. Computer programs can also be deployed in any form, either as standalone programs or as modules, components, subroutines, objects, or other units suitable for use in a computing environment. Computer programs may, but do not necessarily, correspond to files in a file system. A program can be contained within other programs, as part of a file holding data (such as one or more scripts stored in a markup language document), as a single file dedicated to the program in question, or as multiple coordinated files (such as a file containing one or more modules, libraries, subprograms, or parts of code). Computer programs can be deployed to run on a single computer, or on multiple computers located in one site or distributed across multiple sites interconnected by a communication network.

[0022] The processes and logic flows described in this specification can be executed by one or more programmable processors that run one or more computer programs that perform actions on input data to produce outputs. The processes and logic flows can also be executed by dedicated logic circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs), or devices can be implemented in this manner. Such specialized circuits are sometimes referred to as computer processors, even if they are not general-purpose processors.

[0023] In an embodiment, the controller 122 may determine whether the detected value is outside a predetermined range of the threshold value. In a further embodiment, the controller 122 may control the first expansion valve 112 based only on the discharge superheat degree. The controller 122 may be configured to increase the opening degree of the first expansion valve 112 when the first sensor 116 detects that at least one of the discharge superheat degree, the discharge pressure, and the discharge temperature is equal to or higher than the first threshold value. The controller 122 may be configured to control the opening degree of the first expansion valve 112 based on at least one of the detected suction superheat degree, the suction pressure, and the suction temperature. However, it is also conceivable and possible that the controller 122 controls the first expansion valve 112 based only on the discharge superheat degree. In some embodiments, the controller 122 may control the expansion valves 112 and 114 based on the elapsed time. After a predetermined time has elapsed, the controller 122 may move the expansion valves 112 and 114 to a substantially open state, a substantially closed state, or from one position to another. The predetermined time may start when the vehicle starts, such as when the engine starts operating. After the predetermined time has elapsed, the controller 122 may control the expansion valves 112 and 114 to open and close the valves 112 and 114, thereby adjusting the flow rate of the fluid passing through the refrigerant loop.

[0024] The degree of superheating and the gas-liquid ratio are calculated based on the detected pressure and temperature, respectively (for example, by the aforementioned processor in the controller 122). The controller 122 can store pressure and temperature maps of the compressor intake and / or compressor discharge in a memory device and determine the degree of superheating based on a comparison of the detected pressure and temperature with the pressure-temperature map. Thus, the sensor can detect the degree of superheating by including a pressure sensor and a temperature sensor, respectively, and the controller 122 can determine the degree of superheating based on the detected pressure and temperature. In some embodiments, the pressure-temperature map can be used in combination with at least one of the compressor intake, compressor speed, compressor discharge, and mixture outlet to determine the magnitude of the opening of the first expansion valve 112 and / or the second expansion valve 114. Furthermore, the discharge and intake conditions of the second compressor 130 may also be detected or calculated in other ways, such as based on the heater core coolant loop temperature or the chiller coolant loop temperature. The controller 122 can also control the expansion valves 112 and 114 by increasing the opening of one of the expansion valves 112 and 114 when the compressor speed increases, and by increasing the opening of one of the expansion valves 112 and 114 when the compressor speed is constant and the intake temperature or discharge temperature increases.

[0025] The bypass loop 106 may include a second expansion valve 114 configured to control the flow of fluid through the bypass loop 106 of the refrigerant loop 102, a first end 132 connected to the main loop 104 between the sensor 116 and the first heat exchanger 124, and the second heat exchanger 126, or a second end 134 connected to the main loop 104 between the first expansion valve 112 and the second compressor 130. The second expansion valve 114 may be located between the first end 132 and the second end 134. The second compressor 130 can produce gas from the refrigerant passing through it, and the gas from the second compressor 130 passes through the bypass loop 106, where it passes through the heat exchanger 124 to be converted into a two-phase mixture of gas and liquid, and then passes through the main loop 104.

[0026] The controller 122 may be configured to control the opening degree of the first expansion valve 112 to be completely closed when the external sensor 120 detects an ambient temperature below the second threshold value. The second threshold value can be, for example, 0°C. The controller 122 can be configured to control the opening and closing of the first expansion valve 112 and / or the second expansion valve 114 based on the degree of suction superheat, the suction gas-liquid ratio, the suction pressure, or the suction temperature detected from the second sensor 118. When the first sensor 116 detects that at least one of the discharge superheat degree, the discharge pressure, and the discharge temperature is equal to or higher than the first threshold value, the controller 122 controls the magnitude of the opening degree of the first expansion valve 112. Also, the controller 122 can control the magnitude of the opening degree of the second expansion valve 114 based on at least one of the degree of suction superheat, the suction pressure, and the suction temperature. When the external sensor 120 detects an ambient temperature below the third threshold value, the controller 122 can control the magnitude of the opening degree of the first expansion valve 112 and the magnitude of the opening degree of the second expansion valve 114 to have a predetermined initial value that is either fully open or smaller than fully open. The controller 122 can control the opening and closing of the first expansion valve 112 and the second expansion valve 114 independently of each other. In an embodiment including the coolant loop 108, one of the sensors is configured to detect the temperature of the coolant within the coolant loop 108, and the controller 122 is configured to control the opening and closing of the first expansion valve 112 and the second expansion valve 114 based on the detected coolant temperature.

[0027] In one embodiment, the controller 122 may store a pressure-temperature map in its memory that correlates discharge pressure with discharge temperature, suction pressure with suction temperature, or both. The pressure-temperature map includes a mapping of pressure and temperature values ​​and a predetermined opening degree or percentage associated with each pressure-temperature value pair. Using the detected temperature and / or pressure, the controller 122 can use the pressure-temperature map to find an appropriate opening degree or a predetermined opening degree for any of the first and second expansion valves 112, 114. For example, if the pressure is 0.2 MPa and the temperature is 30°C, the pressure-temperature map may set the relative expansion valve opening degree to 30% of the maximum fluid flow rate. The controller 122 is configured to control the opening and closing of the first expansion valve based on the pressure-temperature map as described above. In a further embodiment, the controller 122 may control the opening and closing of the expansion device based on the compressor speed. For example, if the controller 122 detects an increase in the compressor speed, the controller 122 is configured to increase the opening degree of the expansion device. Furthermore, for example, if the detected compressor speed remains constant and the detected intake temperature or the detected discharge temperature rises, the controller 122 is configured to increase the opening degree of the expansion device.

[0028] The controller 122 can define multiple operating modes for controlling parameters related to the refrigerant loop 102. These operating modes may include a normal start mode and a cold start mode. The normal start mode is activated when the detected ambient temperature is outside the optimal temperature range for heating the vehicle components. For example, the normal start mode is activated when the detected ambient temperature is between 15°C and 30°C. The cold start mode is activated when the detected ambient temperature is below 0°C. If the controller 122 selects the cold start mode from the multiple operating modes, the controller 122 may fully open or close the first and second expansion valves 112, 114 to increase the refrigerant flow rate through the second compressor 130. In some embodiments, the multiple operating modes may include a switch start mode, which is activated by activating a switch communicatively coupled to the controller 122 to send a signal to the controller 122 to activate the switch start mode. The switch-operated mode may include the same functions as the cold-start mode, including the ability to select the opening of the first expansion valve 112 and the second expansion valve 114 to fully open, fully closed, substantially open, substantially closed, or an intermediate position between fully open and fully closed. When the switch-operated mode is activated, the controller 122 may be configured to control the opening of the first expansion valve 112 to fully open, fully closed, substantially open, substantially closed, or an intermediate position between fully open and fully closed, and to control the opening of the second expansion valve 114 to fully open, fully closed, substantially open, substantially closed, or an intermediate position between fully open and fully closed.

[0029] Referring to Figure 3, a flowchart of method 300 for operating the refrigerant loop is shown. This method may be performed by one or more controllers and / or processors disclosed in this specification. Step 302 may include detecting the operating environment. The operating environment may be ambient temperature, as disclosed in this specification. Step 304 may include determining whether the operating environment is a predefined environment. If it is determined that the operating environment is not a predefined environment, method 300 returns to step 302. If it is determined that the operating environment is a predefined environment, method 300 proceeds to step 306. Step 306 may include defining the operating mode and related parameters (e.g., initial openings of valves 112, 114) based on the detected operating environment. The initial openings of expansion valves 112, 114 may be substantially open or substantially closed. The operating mode can be selected from several options, including a cold start mode that is activated when the detected ambient temperature is below 0°C.

[0030] Step 308 may include determining whether the current opening of the expansion valves 112, 114 is the initial opening of the expansion valves 112, 114. In some embodiments, Method 300 may determine whether the current opening is outside a predetermined range of the initial opening. If the current opening is not equal to the initial opening, Method 300 may proceed to step 310, which adjusts the current opening of the expansion valves 112, 114 to the initial valve opening. If the current opening is equal to the initial opening, Method 300 may proceed to step 312, which determines the discharge characteristics of the compressor. The discharge characteristics of the compressor may be the discharge superheat, discharge pressure, and / or discharge temperature.

[0031] In step 314, method 300 may include controlling the opening of expansion valves 112, 114 based on the discharge characteristics of the compressor. The opening can be controlled by changing the magnitude of the opening of the expansion valves if the discharge superheat, discharge pressure, discharge temperature, suction superheat, suction pressure, and / or suction temperature exceed a threshold or are outside a predetermined range of the threshold. In embodiments, the threshold may be in the range of 0°C to 30°C. In step 316, method 300 may include determining the suction characteristics of the compressor. The suction characteristics of the compressor may be the suction superheat, suction pressure, and / or suction temperature.

[0032] In step 318, method 300 may include determining whether the compressor's suction characteristics are equal to or outside a predetermined range of predefined conditions. If the compressor's suction characteristics do not match the predefined conditions, method 300 may return to step 314. If the compressor's suction characteristics are equal to the predefined conditions, method 300 may proceed to step 320. In step 320, method 300 may include controlling the opening of the expansion valves 112, 114 based on the suction and discharge characteristics.

[0033] Referring to Figure 4, a flowchart of another method 400 for operating the refrigerant loop is shown. This method may be performed by one or more of the controllers and / or processors disclosed in this specification. In step 402, method 400 may determine vehicle conditions, such as sensing freezing of an external heat exchanger via sensors or determining that the heating power from the system is below a threshold. The heating power may be determined by the temperature of the air coming out of the heating system, the coolant, or the refrigerant. In step 404, method 400 may determine whether the vehicle conditions are equal to or outside a predetermined range of predefined vehicle conditions, such as those disclosed in this specification. If the vehicle criteria are not equal to the predefined vehicle criteria, method 400 returns to step 402. If the vehicle criteria are equal to the predefined vehicle criteria, method 400 proceeds to step 406. In step 406, method 400 may include defining an operating mode and related parameters (e.g., the heating capacity of the system, the freezing state of the heat exchanger, etc.) based on the detected operating environment.

[0034] Step 408 may include determining whether the current mode is equal to a determined operating mode. If the current mode is a determined operating mode, method 400 proceeds to step 410. If the current mode is not a determined operating mode, method 400 proceeds to step 412. Step 410 may include switching the current operating mode. Step 412 may include determining the discharge characteristics of the compressor. Step 414 may include controlling the opening of the expansion valves 112, 114 based on the discharge characteristics of the compressor.

[0035] Step 416 of Method 400 may include determining the suction characteristics of the compressor, and Step 418 of Method 400 may include determining whether the suction characteristics of the compressor are equal to or outside a predetermined range of predefined conditions. If the suction characteristics of the compressor do not match the predefined conditions, Method 400 may return to Step 414. If the suction characteristics of the compressor are equal to the predefined conditions, Method 400 may proceed to Step 420. In Step 420, Method 400 may include controlling the opening of the expansion valves 112, 114 based on the suction and discharge characteristics.

[0036] This disclosure is further defined with respect to the following provisions.

[0037] Section 1 The refrigerant loop comprises at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, at least one sensor for detecting at least one of the discharge superheat (SH), discharge pressure, discharge temperature, and compressor speed from the compressor, and a controller communicatively coupled to at least one sensor, the controller controlling the opening and closing of the first expansion valve based on at least one of the detected discharge superheat (SH), discharge pressure, discharge temperature, and compressor speed, and the controller further modulates the opening of the first expansion valve so that at least one of the detected discharge superheat, discharge pressure, discharge temperature, and compressor speed falls within a predetermined range of first values.

[0038] Section 2 The refrigerant loop of the first paragraph further comprises a second sensor communicatively coupled to a controller, the second sensor being located on the suction side of the compressor and configured to detect that at least one of the suction superheat, suction pressure, and suction temperature is greater than or equal to a second threshold, and a first sensor being located on the discharge side of the compressor, wherein the controller changes the magnitude of the opening of a first expansion valve when the first sensor detects that at least one of the discharge superheat, discharge pressure, and discharge temperature is greater than or equal to a first threshold, and the controller controls the magnitude of the opening of the first expansion valve based on the detected at least one of the suction superheat, suction pressure, and suction temperature.

[0039] Section 3 A refrigerant loop according to paragraph 1 or 2, further comprising an external sensor communicatively coupled to a controller, wherein the controller controls the opening of a first expansion valve to substantially close when the external sensor detects an ambient temperature below a third threshold.

[0040] Section 4 The third refrigerant loop has a second threshold of 0°C.

[0041] Section 5 In any of the refrigerant loops described above, the controller controls the first expansion valve based solely on the discharge superheat.

[0042] Section 6 A refrigerant loop according to any of the above items, further comprising a second sensor located on the suction side of the compressor, the second sensor being configured to detect either the suction superheat of the compressor, the suction gas-liquid ratio, the suction pressure, or the suction temperature, and comprising a bypass loop including a second expansion valve, wherein the controller is configured to control the opening and closing of the second expansion valve based on the detected suction superheat, suction gas-liquid ratio, suction pressure, or suction temperature.

[0043] Section 7 A refrigerant loop as described in any of the above sections, wherein a pressure-temperature map is stored in the controller, and the controller is configured to control the opening of a first expansion valve based on the pressure-temperature map and at least one of the detected discharge pressure and the detected discharge temperature.

[0044] Section 8 A refrigerant loop according to any of the above items, wherein at least one sensor includes a first sensor and a second sensor, the first sensor being configured to detect at least one of discharge superheat, discharge pressure, and discharge temperature, the second sensor being configured to detect at least one of suction superheat, suction pressure, and suction temperature, and the controller being configured to store a pressure-temperature map relating discharge superheat, discharge pressure, or discharge temperature to suction superheat, suction pressure, or suction temperature.

[0045] Section 9 In the refrigerant loop described above, if the detected compressor speed remains constant and the detected intake temperature or the detected discharge temperature rises, the controller is configured to increase the opening of the first expansion device.

[0046] Section 10 In any of the refrigerant loops described above, if the controller detects an increase in compressor speed, the controller is configured to increase the opening of the first expansion device.

[0047] Section 11 The main loop includes at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, a sensor that detects at least one of the following from the compressor: discharge superheat (SH), discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time, a bypass loop configured to control the flow of refrigerant through the refrigerant loop, and a controller that controls the opening and closing of the first and second expansion valves based on the detected discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time.

[0048] Section 12 A refrigerant loop according to paragraph 11, wherein at least one heat exchanger of the main loop includes a first heat exchanger located between a sensor and a first expansion valve and a second heat exchanger located between the first expansion valve and a compressor, and the bypass loop includes a first end connected to the main loop between the sensor and the first heat exchanger and a second end connected to the main loop between the second heat exchanger and a compressor, and the second expansion valve located between the first end and the second end.

[0049] Section 13 A refrigerant loop as described in paragraph 12, wherein only gas passes through the bypass loop.

[0050] Section 14 The refrigerant loop in paragraph 13, wherein the controller independently controls the opening and closing of the first expansion valve and the second expansion valve.

[0051] Section 15 A refrigerant loop according to any of paragraphs 11 to 14, wherein the controller controls the opening of a first expansion valve when the first sensor detects that at least one of the discharge superheat, discharge pressure, and discharge temperature is greater than or equal to a first threshold, and the controller controls the opening of a second expansion valve based on at least one of the suction superheat, suction pressure, and suction temperature.

[0052] Section 16 A refrigerant loop according to any of paragraphs 11 to 15, further comprising an external sensor communicatively coupled to a controller, wherein the controller controls the opening of a first expansion valve to substantially close and the opening of a second expansion valve to substantially open when the external sensor detects an ambient temperature below a third threshold.

[0053] Section 17 A heating system comprising a refrigerant loop according to any of paragraphs 11 to 16 and a coolant loop connected to the refrigerant loop by at least one heat exchanger of the refrigerant loop, wherein a sensor is configured to detect the temperature of the coolant in the coolant loop, and a controller is configured to control the opening and closing of a first expansion valve and a second expansion valve based on the detected coolant temperature.

[0054] Section 18 A refrigerant loop according to any of paragraphs 11 to 17, wherein the maximum opening size of the second expansion valve is greater than the maximum opening size of the first expansion valve.

[0055] Section 19 In any of the refrigerant loops described in paragraphs 11 through 18, the first expansion valve and the second expansion valve are controlled by the controller based on coupling logic / proportional logic using the same control signal.

[0056] Section 20 A method for operating a refrigerant loop, comprising: specifying an initial opening of an expansion valve, the initial opening being substantially open or substantially closed; detecting a discharge superheat from a compressor; determining whether the discharge superheat is outside a predetermined range of a threshold; and, if the discharge superheat is outside a predetermined range of a threshold, changing the magnitude of the opening of the expansion valve.

[0057] Section 21 The method of paragraph 20, further comprising defining one of a plurality of operating modes, the operating mode being a cold start mode which is activated when the detected ambient temperature is below 0°C.

[0058] Section 22 The method according to either paragraph 20 or 21, further comprising maintaining the opening of the expansion valve when the discharge superheat is below a threshold.

[0059] Section 23 One of the methods described in paragraphs 20 to 22, wherein the threshold is within the range of 0°C to 50°C.

[0060] Section 24 Any method according to paragraphs 20 to 23, further comprising defining an initial opening of the second expansion valve, wherein the initial opening of the second expansion valve is fully open.

[0061] Section 25 A method according to any of paragraphs 20 to 24, further comprising detecting one of the following: the intake superheat of the compressor, the intake gas-liquid ratio, the intake pressure, or the intake temperature, and controlling the opening of the second expansion valve based on the detected intake superheat, intake gas-liquid ratio, intake pressure, or intake temperature.

[0062] Section 26 A refrigerant loop comprising at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, at least one sensor for detecting at least one of the following: suction superheat (SH), suction pressure, suction temperature, and compressor speed, and a controller communicatively coupled to at least one sensor, the controller controlling the opening and closing of the first expansion valve based on at least one of the detected discharge superheat (SH), discharge pressure, discharge temperature, and compressor speed, and the controller further modifying the magnitude of the opening of the first expansion valve so that at least one of the detected discharge superheat, discharge pressure, discharge temperature, and compressor speed falls within a predetermined range of first values.

[0063] Section 27 A refrigerant loop according to paragraph 26, wherein a pressure-temperature map relating an intake pressure to an intake temperature is stored in the controller, and the controller is configured to control the opening of a first expansion valve based on the pressure-temperature map and at least one of a detected discharge pressure and a detected discharge temperature.

[0064] Section 28 A refrigerant loop according to either paragraph 26 or 27, wherein the controller is configured to calculate a compressor intake gas-liquid ratio based on at least one of the detected intake SH, intake pressure, intake temperature, compressor speed, and magnitude of the first expansion valve opening, and the controller controls the opening of the first expansion valve based on the compressor intake gas-liquid ratio.

[0065] Section 29 A refrigerant loop comprising at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, a sensor for detecting at least one of the following: discharge superheat (SH), discharge pressure, discharge temperature, suction superheat, suction pressure, suction temperature, and compressor speed, and a controller communicatively coupled to at least one of the sensors, the controller controlling the opening and closing of the first expansion valve based on at least one of the detected discharge superheat (SH), discharge pressure, discharge temperature, suction SH, suction pressure, suction temperature, and compressor speed, and the controller changing the magnitude of the opening of the first expansion valve when at least one of the detected discharge superheat, discharge pressure, discharge temperature, suction SH, suction pressure, suction temperature, and compressor speed is outside a predetermined range of first values.

[0066] Section 30 A method for operating a refrigerant loop, comprising: specifying an initial opening of an expansion valve, the initial opening being substantially open or substantially closed; detecting the suction superheat to the compressor; determining whether the suction superheat is outside a predetermined range of thresholds; and, if the suction superheat is outside a predetermined range of thresholds, changing the magnitude of the opening of the expansion valve.

[0067] Section 31 A method for operating a refrigerant loop, comprising: determining the initial opening of the first expansion valve, wherein the initial opening of the first expansion valve is substantially open or substantially closed; determining the initial opening of the second expansion valve, wherein the initial opening of the expansion valve is substantially open or substantially closed; receiving the characteristics of the compressor, heater core, and coolant flowing through the coolant loop; and determining the characteristics of the first expansion valve based on the characteristics of the compressor, heater core, and coolant. The method includes determining a target opening degree, determining a target opening degree of a second expansion valve based on at least one characteristic of at least one of the compressor, heater core, and coolant, setting the initial opening degree of the first expansion valve to the target opening degree of the first expansion valve in response to at least one characteristic of the compressor, heater core, and coolant satisfying predetermined conditions, and setting the initial opening degree of the second expansion valve to the target opening degree of the second expansion valve in response to at least one characteristic of the compressor, heater core, and coolant satisfying predetermined conditions.

[0068] Section 32 A method for operating the refrigerant loop of paragraph 31, wherein at least one characteristic is at least one of the following: discharge superheat (SH) from the compressor, discharge temperature, discharge pressure, suction SH, suction temperature, suction pressure, refrigerant temperature, coolant temperature, temperature associated with the heater core, compressor speed, and duration.

[0069] Section 33 A method for operating a refrigerant loop, comprising: determining the initial opening of a first expansion valve, wherein the initial opening of the first expansion valve is substantially open or substantially closed; determining the initial opening of a second expansion valve, wherein the initial opening of the expansion valve is substantially open or substantially closed; receiving at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from a compressor; determining a target opening of the first expansion valve based on at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from a compressor; and receiving at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from a compressor. The method includes determining the target opening of the second expansion valve based on one of the following: setting the initial opening of the first expansion valve to the target opening of the first expansion valve based on comparing at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from the compressor with a predetermined condition in response to the initial opening of the first expansion valve not being equal to the target opening of the first expansion valve; and setting the initial opening of the second expansion valve to the target opening of the second expansion valve based on comparing at least one of the discharge superheat (SH), discharge pressure, and discharge temperature from the compressor with a predetermined condition in response to the initial opening of the second expansion valve not being equal to the target opening of the second expansion valve.

[0070] Section 34 In a refrigerant loop, the main loop includes at least one heat exchanger, a first expansion valve configured to control the flow of refrigerant through the refrigerant loop, a compressor, a bypass loop which includes a second expansion valve configured to control the flow of refrigerant through the refrigerant loop, and a controller configured to control the opening and closing of the first and second expansion valves based on characteristics related to the compressor, heater core, and at least one of the coolant flowing through the coolant loop. While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms included in the claims. The terminology used in this specification is descriptive, not restrictive, and it should be understood that various modifications can be made without departing from the spirit and scope of this disclosure. As stated above, further embodiments of this invention, which may not be expressly described or illustrated, can be formed by combining features of various embodiments. While various embodiments are described as offering advantages or being preferable to other embodiments or prior art implementations with respect to one or more desired characteristics, depending on the specific application and implementation, those skilled in the art should recognize that one or more features or characteristics may be compromised to achieve the desired overall system attribute. These attributes include a number of elements, not limited to, such as cost, strength, durability, lifecycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, and ease of assembly. Therefore, even if any embodiment is described as being undesirable to other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of this disclosure and may be desirable for a particular application.

Claims

1. The main loop (104) is, At least one heat exchanger (110), A first expansion valve (112) configured to control the flow of refrigerant through the main loop, Compressor (130), A sensor (116) for detecting at least one of the following from the compressor: discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time period. A bypass loop (106) is provided with a second expansion valve (114) configured to control the flow of refrigerant through the refrigerant loop, A refrigerant loop comprising a controller (122) that controls the opening and closing of the first expansion valve and the second expansion valve based on the detected discharge superheat, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, and time.

2. A refrigerant loop according to claim 1, The main loop's at least one heat exchanger comprises a first heat exchanger (124) positioned between the sensor and the first expansion valve, and a second heat exchanger (126) positioned between the first expansion valve and the compressor. The bypass loop comprises a first end (132) connected to the main loop between the sensor and the first heat exchanger, and a second end (134) connected to the main loop between the first expansion valve and the second heat exchanger, wherein the second expansion valve is a refrigerant loop positioned between the first end and the second end.

3. A refrigerant loop according to claim 2, wherein only gas passes through the bypass loop.

4. A refrigerant loop according to claim 3, wherein the controller independently controls the opening and closing of the first expansion valve and the second expansion valve.

5. A refrigerant loop according to any one of claims 1 to 4, The controller controls the degree of opening of the first expansion valve based on at least one of the discharge superheat, discharge pressure, and discharge temperature. The controller controls the magnitude of the opening of the second expansion valve based on at least one of the intake superheat, intake pressure, and intake temperature of the refrigerant loop.

6. A refrigerant loop according to any one of claims 1 to 5, further comprising an external sensor (120) communicatively coupled to the controller, wherein the controller controls the opening of the first expansion valve to substantially close and the opening of the second expansion valve to substantially open when the external sensor detects an ambient temperature below a third threshold.

7. The refrigerant loop according to any one of claims 1 to 6, The refrigerant loop comprises at least one heat exchanger connected to the refrigerant loop, and a cooling liquid loop (108) connected to the refrigerant loop. The sensor is configured to detect the temperature of the coolant in the coolant loop. The controller is configured to change the opening degree of the first expansion valve and the opening degree of the second expansion valve based on the detected temperature of the coolant in the heating system.

8. Specify the initial opening of the expansion valve (112), whether the initial opening is substantially open or substantially closed. To determine the characteristics of the discharge side of the compressor (130), To determine whether the characteristics of the discharge side of the compressor are outside a predetermined range of a threshold, and A method for operating a refrigerant loop, which includes changing the magnitude of the opening of the expansion valve in response to the characteristics of the discharge side of the compressor being outside a predetermined range of a threshold.

9. A method according to claim 8, further comprising defining one of a plurality of operating modes, the operating mode including a cold start mode which is activated when the detected ambient temperature is below 0°C.

10. A method according to claim 9, further comprising reducing the opening of the expansion valve when the discharge superheating degree falls below a threshold.

11. A method according to claim 9 or 10, wherein the threshold is in the range of 0°C to 50°C.

12. A method according to any one of claims 9 to 11, further comprising defining an initial opening of a second expansion valve (114), wherein the initial opening of the second expansion valve is fully open.

13. A method according to any one of claims 9 to 12, further, The compressor's intake superheating degree, intake gas-liquid ratio, intake pressure, or intake temperature are to be detected, and A method comprising controlling the opening degree of a second expansion valve based on the detected intake superheat, intake gas-liquid ratio, intake pressure, or intake temperature.

14. A method according to any one of claims 9 to 13, Multiple operating modes include a switch-activated mode which is activated by the activation of a switch communicatively coupled to the controller. A method in which the switch activation mode includes controlling the opening of the expansion valve to be substantially open.

15. To determine the characteristics of the discharge side of the compressor (130), Controlling the expansion valve (112) using a first method, wherein the first method includes control logic based on the characteristics of the discharge side of the compressor. To determine the characteristics of the suction side of the compressor, and A method for operating a refrigerant loop, which includes controlling the expansion valve using a second method, the second method comprising control logic based on the characteristics of the suction side of the compressor, in response to the characteristics of the suction side of the compressor meeting a predetermined criterion.

16. The method according to claim 15, The characteristics of the discharge side of the compressor are at least one of the discharge temperature, discharge pressure, and discharge superheating degree. The method wherein the characteristics of the suction side of the compressor are at least one of the suction temperature, suction pressure, and suction superheat.

17. To detect conditions related to the operating environment of the refrigerant loop (102), Based on the detected state, define at least one operating mode of the first expansion valve (112) and the second expansion valve (114), and related parameters, the related parameters including: a first initial opening of the first expansion valve, wherein the initial opening of the first expansion valve is substantially open or substantially closed; and a second initial opening of the second expansion valve, wherein the initial opening of the expansion valve is substantially open or substantially closed. Setting the first expansion valve to the first initial opening and setting the second expansion valve to the second initial opening, To determine the characteristics of the discharge side of the compressor (130), Based on the characteristics of the discharge side of the compressor, the opening degree of at least one of the first expansion valve and the second expansion valve is controlled. To determine the characteristics of the suction side of the compressor, A method for operating a refrigerant loop, which includes controlling the opening degree of at least one of the first expansion valve and the second expansion valve based on suction and discharge characteristics in response to the suction side characteristics of the compressor satisfying predetermined characteristics.

18. A method for operating a refrigerant loop according to claim 17, wherein at least one characteristic is at least one of the following: discharge superheat from the compressor, discharge temperature, discharge pressure, suction superheat, suction temperature, suction pressure, refrigerant temperature, coolant temperature, temperature associated with the heater core, compressor speed, and duration.

19. The main loop (104) is, At least one heat exchanger (110), A first expansion valve (112) configured to control the flow of refrigerant through the main loop, Compressor (130), A first sensor (116) configured to output the characteristics of the suction side of the compressor, A second sensor (118) configured to output the characteristics of the discharge side of the compressor, A bypass loop (106) is provided with a second expansion valve (114) configured to control the flow of refrigerant through the refrigerant loop, In response to conditions related to the operating environment of the refrigerant loop, the opening and closing of at least one of the first expansion valve and the second expansion valve is controlled using a first method, the first method including a control logic based on the characteristics of the compressor discharge side, A refrigerant loop comprising a controller (122) configured to perform switching control of the opening and closing of the first expansion valve and at least one of the second expansion valve using a second method, the second method including control logic based on the characteristics of the suction side of the compressor, in response to the characteristics of the suction side of the compressor meeting a predetermined criterion.

20. A refrigerant loop according to claim 19, The characteristics of the discharge side of the compressor are at least one of the discharge temperature, discharge pressure, and discharge superheating degree. The suction side characteristics of the compressor are at least one of the suction temperature, suction pressure, and suction superheat.

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