Parallel compressor climate system

Abstract

A climate system and a method for controlling the climate system are disclosed. A climate system includes a plurality of compressors arranged in parallel, a condenser arranged downstream of the compressors, and an evaporator arranged downstream of the condenser. The compressors, the condenser, and the evaporator are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls operation of the compressors to return lubricant to the compressors without using an oil equalization system.

Description

[0001] Related applications This application is a divisional application of Chinese application No. 201611168991.X, filed on December 16, 2016, entitled "Parallel Compressor Climate System". Technical Field

[0002] This invention generally relates to climate systems and control methods thereof, and more specifically, to vehicle climate systems using parallel compressors and control methods that enable compressor oil to return to the compressor without using an oil equalization system. Background Technology

[0003] As is well known, almost all compressors require some form of lubricant (e.g., oil) to cool, seal, or lubricate internal components. Typically, only static jet compressors and oil-free compressors with rotors suspended in magnetic or air bearings do not require some type of lubrication. In refrigeration systems using compressors, a small portion of the compressor lubricant is entrained by the refrigerant and discharged from the compressor. This entrained lubricant can cause several problems. For example, in a system with a single compressor, excessive entrained lubricant in the refrigerant can significantly reduce heat transfer and efficiency in the condenser and evaporator. In systems with two or more compressors, in addition to affecting heat transfer and efficiency in the condenser and evaporator, the entrained lubricant may not return evenly or properly to the two compressors, thus providing too much lubricant to one compressor and too little to the other. This problem is exacerbated when compressors are arranged in parallel.

[0004] Some traditional systems address this issue by using an oil equalization line system, which connects to the compressor crankcase or oil pan via an oil equalization line. This method typically requires compressors of the same size and capacity, installed at the same level or height. Other traditional systems employ an oil separator (separate or shared) to separate oil from the refrigerant, then return the separated oil to the compressor. These systems are inherently complex, more expensive, and / or more difficult to maintain and control.

[0005] Against this background, there is a need in the art for climate systems and control methods that are simple, cheaper, and / or easy to control, while also realizing the benefits of parallel compressor configurations.

[0006] The information disclosed in the Background section is provided merely to provide a general background to the embodiments described herein and is not intended to acknowledge or imply that such information forms part of the prior art known to those skilled in the art. Summary of the Invention

[0007] Various aspects of the present invention provide climate systems and control methods that are easy to manufacture and operate, cheaper and easier to control, while realizing the benefits of parallel compressor configurations.

[0008] One embodiment provides a climate system for cooling a vehicle compartment. The climate system includes multiple compressors, a condenser, an evaporator, refrigerant lines, and a controller. The multiple compressors are arranged in parallel and are used to compress refrigerant into compressed refrigerant. A condenser is located downstream of the multiple compressors and is used to condense the compressed refrigerant. An evaporator is located downstream of the condenser and is used to evaporate the condensed refrigerant. The evaporator is thermally coupled to the vehicle compartment to cool the compartment. The refrigerant lines fluidly connect the multiple compressors, condenser, and evaporator to form a refrigerant loop for circulating the refrigerant. The controller is electrically coupled to first and second compressors and is configured to automatically and independently control the operation of the first and second compressors to return compressor oil to the first and second compressors.

[0009] The plurality of compressors includes a first compressor and a second compressor. In one embodiment, at least one of the first compressor and the second compressor is a double rotary vane compressor. In another embodiment, one of the first compressor and the second compressor is a single rotary vane compressor. The first compressor includes a first refrigerant inlet, a first refrigerant outlet, and a first oil sump. The second compressor includes a second refrigerant inlet, a second refrigerant outlet, and a second oil sump. The first refrigerant inlet of the first compressor is fluidly connected to the second refrigerant inlet of the second compressor. The first refrigerant outlet of the first compressor is fluidly connected to the second refrigerant outlet of the second compressor. The first oil sump is independent of the second oil sump. In one embodiment, the first oil sump of the first compressor is independent of the second oil sump of the second compressor because the first oil sump of the first compressor is not fluidly connected to the second oil sump of the second compressor. In another embodiment, the first oil sump of the first compressor is independent of the second oil sump of the second compressor because the first oil sump and the second oil sump are not connected via an oil equalization system.

[0010] In some embodiments, the controller automatically controls the operation of multiple compressors to allow compressor oil to return to the compressor. In one embodiment, before shutting down the first compressor, the controller causes the first compressor to operate in a first low-speed range for a first low-speed period to allow compressor oil to return to the first oil sump. Control of the first compressor to operate in the first low-speed range for the first low-speed period is performed each time the first compressor is about to be shut down, at regular intervals when the first compressor is about to be shut down, or after the first compressor has operated in a first high-speed range for a first high-speed period. In one embodiment, before shutting down the second compressor, the controller causes the second compressor to operate in a second low-speed range for a second low-speed period to allow compressor oil to return to the second oil sump. Control of the second compressor to operate in the second low-speed range for a second low-speed period is performed each time the second compressor is about to be shut down, at regular intervals when the second compressor is about to be shut down, or after the second compressor has operated in a second high-speed range for a second high-speed period.

[0011] In one embodiment, the climate system further includes a sensor for measuring atmospheric temperature and a thermostat for receiving a desired temperature and detecting the interior temperature of the vehicle compartment. The controller is electrically coupled to the sensor and the thermostat and controls the operation of the first and second compressors based on the atmospheric temperature, the interior temperature, and the desired temperature.

[0012] In one embodiment, the climate system further includes a first blower and / or a second blower. The first blower is located near the condenser and is configured to perform one or more of the following: blowing air into the condenser to cool it and exhausting interior air from the vehicle compartment to reduce the heat load on the compartment. The second blower is configured to draw outside air or fresh air into the vehicle compartment if the interior temperature exceeds a desired temperature and the ambient temperature. The first and second blowers may operate simultaneously, alternately, or independently. In some embodiments, the climate system is integrated with the vehicle's existing air conditioning system because the first and / or second blowers are shared by the climate system and the existing air conditioning system.

[0013] Another embodiment provides a first method for controlling a climate system. The first method includes: (a) receiving a desired temperature of the vehicle compartment and an ambient temperature outside the vehicle; (b) monitoring the internal temperature of the vehicle compartment; (c) determining whether the internal temperature is higher than the desired temperature; (d) determining whether the internal temperature is higher than the ambient temperature; (e) if the internal temperature exceeds both the desired temperature and the ambient temperature, activating a first blower to expel internal air from the vehicle compartment; (f) if the internal temperature is higher than the desired temperature but lower than or equal to the ambient temperature, determining whether the heat load of the vehicle compartment exceeds a first heat threshold; (g) if the heat load of the vehicle compartment is less than or equal to the first heat threshold, activating a first compressor or a second compressor; and (h) if the heat load of the vehicle compartment exceeds the first heat threshold, activating the first compressor and the second compressor.

[0014] In some embodiments, the first method further includes one or more additional or optional steps. In one embodiment, the first method includes: operating the first compressor in a first low-speed range for a first low-speed period before shutting down the first compressor to allow compressor oil to return to a first oil sump; and / or operating the second compressor in a second low-speed range for a second low-speed period before shutting down the second compressor to allow compressor oil to return to a second oil sump. In some embodiments, the control to operate the first compressor in the first low-speed range for the first low-speed period is performed each time the first compressor is about to be shut down, at intervals when the first compressor is about to be shut down, or after the first compressor has operated in the first high-speed range for a first high-speed period. The control to operate the second compressor in the second low-speed range for the second low-speed period is performed each time the second compressor is about to be shut down, at intervals when the second compressor is about to be shut down, or after the second compressor has operated in the second high-speed range for a second high-speed period.

[0015] In some embodiments, the first method includes: determining whether compressor oil needs to be returned to the first compressor based on whether the first compressor has been operating in a first high-speed range and for how long; and determining whether compressor oil needs to be returned to the second compressor based on whether the second compressor has been operating in a second high-speed range and for how long. Based on this determination, in some embodiments, if the first compressor has been operated in the first high-speed range for a first high-speed period, the first method causes the first compressor to operate in a first low-speed range for a first low-speed period to return the compressor oil to the first compressor; and / or if it is determined that the second compressor has been operated in the second high-speed range for a second high-speed period, the first method causes the second compressor to operate in the second low-speed range for a second low-speed period to return the compressor oil to the second compressor.

[0016] In one embodiment, the first method further includes: if the internal temperature simultaneously exceeds both the desired temperature and the atmospheric temperature, activating a second blower installed in the vehicle to draw outside air or fresh air into the vehicle's passenger compartment. In another embodiment, the first method further includes: before activating the second blower, opening or closing a door in the ductwork of the vehicle's existing air conditioning system, wherein opening or closing the door allows the second blower to blow outside air or fresh air into the vehicle's passenger compartment.

[0017] Other embodiments provide a second method for controlling a climate system. The second method includes: (a) receiving a desired temperature of the vehicle compartment and an ambient temperature outside the vehicle; (b) determining whether the heat load of the vehicle compartment exceeds a first heat threshold; (c) if the heat load of the vehicle compartment is less than or equal to the first heat threshold, turning on a first compressor or a second compressor; (d) if the heat load of the vehicle compartment exceeds the first heat threshold, turning on the first compressor and the second compressor; and (e) performing one or more of the following: operating the first compressor in a first low-speed range for a first low-speed period before shutting down the first compressor to allow compressor oil to return to a first oil tank; and operating the second compressor in a second low-speed range for a second low-speed period before shutting down the second compressor to allow compressor oil to return to a second oil tank.

[0018] In some embodiments, before operating the first and / or second compressors in a low-speed range, the second method further includes one or more of the following additional or optional steps: determining whether compressor oil needs to be returned to the first compressor based on whether the first compressor has been operating in a first high-speed range and for how long; and determining whether compressor oil needs to be returned to the second compressor based on whether the second compressor has been operating in a second high-speed range and for how long. Following this determination, in some embodiments, if the first compressor has been operated in the first high-speed range for a first high-speed period, the second method operates the first compressor in a first low-speed range for a first low-speed period to return the compressor oil to the first compressor; and if it is determined that the second compressor has been operated in the second high-speed range for a second high-speed period, the second method operates the second compressor in the second low-speed range for a second low-speed period to return the compressor oil to the second compressor.

[0019] Other features and advantages of the systems and methods of the present invention will become apparent from the accompanying drawings, which are incorporated herein and the detailed description thereof, which are also set forth in more detail in the accompanying drawings and the detailed description thereof. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate one or more embodiments of the present application and, together with the embodiments, serve to explain the principles and implementation of the present application.

[0021] Figure 1 This is a block diagram of a climate system according to some embodiments.

[0022] Figure 2 yes Figure 1 A block diagram of the climate system, including some additional and / or optional components.

[0023] Figure 3This is a flowchart of a first exemplary method for controlling a climate system according to some embodiments.

[0024] Figure 4 yes Figure 3 The flowchart of the first exemplary method includes some additional and / or optional steps.

[0025] Figure 5 yes Figure 3 The flowchart of the first exemplary method includes some additional and / or optional steps.

[0026] Figure 6 This is a flowchart of a second exemplary method for controlling a climate system, based on some embodiments. Detailed Implementation

[0027] Referring now to the embodiments of this application illustrated in the accompanying drawings. Throughout the drawings and the following detailed description, the same reference numerals will be used to refer to the same or similar parts. Those skilled in the art will recognize that the following detailed description of this application is merely illustrative and not intended to be limiting in any way. Other embodiments of this application will readily conceive of those skilled in the art who will benefit from this invention.

[0028] For clarity, not all conventional features of the embodiments described herein have been shown or described. It should be understood, of course, that in the development of any such practical embodiment, numerous specific implementation decisions must be made to achieve the developer's specific objectives, such as complying with application and business-related constraints, and these specific objectives will vary depending on the implementation and the developer. Furthermore, it should be understood that such development work may be complex and time-consuming, but is a routine engineering task for those skilled in the art who will benefit from this invention.

[0029] Various modifications and variations can be made to this invention without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are provided by way of example only, and the invention will be limited only by the terms of the appended claims and the full scope of their equivalents.

[0030] Embodiments of the invention are described herein in the section on climate systems for vehicles and methods for controlling such climate systems. Vehicles as used herein may be automobiles, vans, trucks, buses, trailers, or other vehicles. The climate system of the invention typically includes two or more compressors connected fluidly in parallel, without an oil equalization system between the compressors. The climate system also includes a condenser, an evaporator, and refrigerant lines fluidly connecting the compressors, condenser, and evaporator to form a refrigerant circuit. The climate system includes a controller, and a novel method is used to control the compressor to recover compressor oil entrained in the refrigerant or carried away by the refrigerant during operation of the climate system. As used herein, the term "compressor oil" refers to a material (e.g., oil, lubricant, sealant) used for cooling, sealing, or lubricating compressor components (e.g., gears). In some embodiments, the compressor is controlled independently according to the heat load.

[0031] Because it eliminates the need for an oil leveling system, the climate system of this invention is more compact and flexible compared to conventional systems. For example, the climate system can use compressors of different sizes and capacities, and these compressors do not need to be installed at the same level, height, or altitude. Therefore, the climate system of this invention can be installed in various ways, such as on the rear wall of a vehicle's sleeper compartment, and / or integrated with other components of the vehicle's existing air conditioning system. Furthermore, by independently controlling these compressors according to the heat load, this invention improves the overall efficiency of the system. In addition, the climate system of this invention requires fewer components, thus offering higher reliability and lower cost compared to climate systems with more components.

[0032] As an example, Figure 1 A climate system (100) is depicted, comprising multiple compressors (e.g., a first compressor (102) and a second compressor (104)), a condenser (118), an evaporator (120), refrigerant lines, and a controller (124). The first compressor (102) includes a first refrigerant inlet (106) and a first refrigerant outlet (108). The second compressor (104) includes a second refrigerant inlet (112) and a second refrigerant outlet (114). From the perspective of the refrigerant, the first compressor (102) and the second compressor (104) are fluidly connected to each other in parallel. For example, in the illustrated embodiment, the first refrigerant inlet (106) of the first compressor (102) is fluidly connected to the second refrigerant inlet (112) of the second compressor (104) via refrigerant lines (e.g., 122-6, 122-7), and the first refrigerant outlet (108) of the first compressor (102) is fluidly connected to the second refrigerant outlet (114) of the second compressor (104) via refrigerant lines (e.g., 122-1, 122-2).

[0033] The first compressor (102) also includes a first oil sump (110), and the second compressor (104) includes a second oil sump (116). The first oil sump (110) of the first compressor (102) is independent of the second oil sump (116) of the second compressor (104). As used herein, the term "oil sump" refers to a reservoir that holds lubricant for cooling, sealing, or lubricating internal components of the compressor, such as gears. In some cases, the oil sump is an oil tank, an oil pan, or simply the space at the bottom of the compressor's crankcase. In some embodiments, the independence between the first oil sump (110) and the second oil sump (116) is characterized in that the first oil sump (110) of the first compressor (102) is not fluidly connected to the second oil sump (116) of the second compressor (104). As used herein, “non-fluidly connected” of the first and second oil tanks means one or more of the following configurations: (i) the first and second oil tanks are not connected by any oil equalization system (e.g., oil line or oil pipe) used in conventional systems to allow oil to flow between different oil tanks and to keep the oil in different oil tanks at the same level; (ii) the first and second oil tanks are not connected by a conventional oil separator used in conventional systems to separate oil from refrigerant; and (iii) the first and second oil tanks are not connected by a conventional suction header or conduit used in conventional systems to return oil to the oil tank after separation from refrigerant.

[0034] In some embodiments, both the first and second compressors are rotary vane compressors. In one embodiment, at least one of the first compressor (102) and the second compressor (104) is a dual rotary vane compressor. In another embodiment, one of the first compressor (102) and the second compressor (104) is a single rotary vane compressor. It should be understood that the first and second compressors are not limited to rotary vane (single or paired) compressors. Any other suitable compressor may be used in the climate system of the present invention, including reciprocating, scroll, helical, or centrifugal compressors. In some embodiments, the first refrigerant inlet (106) of the first compressor (102) includes two or more refrigerant inlets, and the first refrigerant outlet (108) of the first compressor (102) includes two or more refrigerant outlets. Similarly, in some embodiments, the second refrigerant inlet (112) of the second compressor (104) includes two or more refrigerant inlets, and the second refrigerant outlet (114) of the second compressor (104) includes two or more refrigerant outlets. In some embodiments, the two or more refrigerant inlets are connected to each other. In some embodiments, the two or more refrigerant outlets are connected to each other.

[0035] A condenser (118) is located downstream of a plurality of compressors and is fluidly connected to the compressors via refrigerant lines (e.g., 122-1, 122-2, 122-3). An evaporator (120) is located downstream of the condenser (118) and is fluidly connected to the condenser (118) via a refrigerant line (e.g., 122-4). In some embodiments, the evaporator (120) is also fluidly connected to the compressors via refrigerant lines (e.g., 122-5, 122-6, 122-7), thereby forming a refrigerant loop for circulating refrigerant.

[0036] During the operation of the climate system (100), multiple compressors compress refrigerant into compressed refrigerant, a condenser (118) condenses the refrigerant that has been compressed by the multiple compressors, and an evaporator (120) evaporates the refrigerant that has been condensed by the condenser (118). The evaporator (120) is thermally coupled to the vehicle compartment to cool the compartment. As used herein, the term "thermally coupled" refers to one or more of the following: (i) the evaporator is installed in the corresponding compartment to exchange heat with the compartment or the air in the compartment; and (ii) the evaporator is coupled to a device (e.g., a heat exchanger or blower) that introduces conditioned air into the compartment. The compartment may be a cab compartment, a sleeper compartment, a combination of a cab compartment and a sleeper compartment, or any space in the vehicle.

[0037] like Figure 1 As shown, the controller (124) is electrically coupled to the first and second compressors. The controller (124) is configured to automatically and independently control the operation of the first and second compressors to return compressor oil to the first and second compressors. In some embodiments, to return compressor oil entrained in or carried away by the refrigerant to the first oil sump (110), the controller (124) causes the first compressor (102) to operate in a first low-speed range for a first low-speed period before shutting down the first compressor (102). In one embodiment, the control of the first compressor (102) to operate in the first low-speed range for the first low-speed period is performed each time the first compressor (102) is about to be shut down. In another embodiment, the control of the first compressor (102) to operate in the first low-speed range for the first low-speed period is performed at regular intervals when the first compressor (102) is about to be shut down. In some embodiments, whether the first compressor (102) is operated in the first low-speed range to recover compressor oil depends on how long the first compressor (102) has been operating in the high-speed range. For example, in some embodiments, in order to return the compressor oil to the first oil sump (110), after the first compressor (102) has been running in the first high speed range for a first high speed period, the controller (124) controls the first compressor (102) to run in the second low speed range for a first low speed period.

[0038] Similarly, in some embodiments, to return compressor oil entrained in or carried away by the refrigerant to the second oil sump (116), the controller (124) causes the second compressor (104) to operate in the second low-speed range for a second low-speed period before shutting down the second compressor (104). In one embodiment, the control of the second compressor (104) to operate in the second low-speed range for a second low-speed period is performed each time the second compressor (104) is about to be shut down. In another embodiment, the control of the second compressor (104) to operate in the second low-speed range for a second low-speed period is performed at regular intervals when the second compressor (104) is about to be shut down. In some embodiments, it is determined whether the second compressor (104) should be operated in the low-speed range to recover compressor oil based on how long the second compressor (104) has been operating in the high-speed range. For example, in some embodiments, to return compressor oil to the second oil sump (116), the controller (124) controls the second compressor (104) to operate in the second low-speed range for a second low-speed period after the second compressor (104) has been operating in the second high-speed range for a second high-speed period.

[0039] In some embodiments, the first or second low-speed range is between 1500 and 3000 rpm, between 1500 and 4500 rpm, or between 1500 and 6500 rpm. In some embodiments, the first or second low-speed period before the first or second compressor (104) is between 5 and 20 seconds, between 20 and 100 seconds, or between 100 and 200 seconds. In some embodiments, the first or second high-speed range is between 1500 and 3000 rpm, between 1500 and 4500 rpm, or between 1500 and 6500 rpm. In some embodiments, the first or second high-speed period is between 5 and 20 seconds, between 20 and 100 seconds, or between 100 and 200 seconds.

[0040] In some embodiments, the controller (124) is configured to automatically and independently control the operation of the first and second compressors, at least in part, based on the heat load of the compartment. In some embodiments, the controller (124) turns on the first or second compressor when the heat load of the compartment is equal to or less than a first threshold, and turns on both the first and second compressors when the heat load of the compartment exceeds the first threshold. In one embodiment, the first and second compressors have the same capacity. In another embodiment, the first and second compressors have different capacities. In some embodiments, the first threshold of the heat load corresponds to the capacity of the first or second compressor. In some embodiments, the first threshold of the heat load is between 0.4 kW and 0.8 kW, between 0.4 kW and 1.0 kW, or between 0.4 kW and 1.6 kW.

[0041] refer to Figure 2 In some embodiments, the climate system (100) of the present invention further includes other additional or optional components. For example, in some embodiments, the climate system (100) further includes a plurality of flow control valves, such as a first flow control valve (204) and a second flow control valve (206). The first flow control valve (204) is disposed upstream of the first compressor (102) and configured to selectively restrict or allow refrigerant flow to the first compressor (102). The second flow control valve (206) is disposed upstream of the second compressor (104) and configured to selectively restrict or allow refrigerant flow to the second compressor (104).

[0042] In some embodiments, the climate system (100) further includes one or more blowers. For example, in the illustrated embodiment, the climate system (100) also includes a first blower (208) adjacent to a condenser (118). The first blower (208) is configured to blow air onto the condenser (118) to cool the condenser (118) and / or exhaust interior air from the compartment to reduce the heat load on the compartment. In some embodiments, the climate system (100) further includes a second blower (214) electrically coupled to a controller (124). The second blower (214) is configured and controlled by the controller (124) to exhaust interior air from the compartment to the outside and / or draw in outside air or fresh air into the compartment. In some embodiments, the climate system (100) is integrated with the vehicle’s existing air conditioning system. In this case, the climate system (100) and the existing air conditioning system share the first blower (208) and / or the second blower (214). In one embodiment, the first and second blowers are installed in the same compartment (e.g., a sleeper compartment or a driver’s cab compartment). In another embodiment, the first and second blowers are installed in different compartments, for example, the first blower (208) is in the sleeper compartment and the second blower (214) is in the driver's cab compartment.

[0043] In some embodiments, to automatically control the compressor, blower, and / or other components in the system, the climate system (100) of the present invention further includes a sensor (210) for measuring atmospheric temperature and a thermostat (212) for setting a desired temperature and monitoring the interior temperature of the vehicle compartment. In this embodiment, the controller (124) is electrically coupled to the sensor (210) and the thermostat (212) and automatically controls the operation of other components (e.g., blower, compressor) based on the atmospheric temperature, the interior temperature, and settings (e.g., desired temperature). For example, when the interior temperature is higher than the atmospheric temperature and the desired temperature, the controller (124) turns on the first blower (208) to expel interior air from the vehicle compartment before turning on the first or second compressor. In embodiments with a second blower (214), the controller (124) additionally or optionally turns on the second blower (214) to draw outside air or fresh air into the vehicle compartment. Thus, the heat load is reduced before the compressor is turned on, thereby improving the overall efficiency of the climate system. When the internal temperature drops to the ambient temperature and the desired temperature is below the ambient temperature, the controller (124) activates the first and / or second compressors to further cool the compartment to the desired temperature. The controller (124) operates the first and / or second compressors (e.g., controls the compressor speed) based on the desired temperature and the ambient temperature.

[0044] In some embodiments, one or more compressors are driven by a power source or multiple energy sources (202). In one embodiment, all compressors are driven by a single power source or multiple energy sources (202). In some embodiments, at least one compressor is driven by the vehicle's internal combustion engine. As an example, Figure 2 The first compressor (102) is configured to be driven by an internal combustion engine, while the second compressor (104) is an electrically driven compressor. The second compressor (104) is configured to operate when the vehicle's internal combustion engine is not running.

[0045] Continue to refer to Figure 2 In some embodiments, the climate system (100) of the present invention further includes a metering device (220) disposed upstream of the evaporator (120). The metering device (220) is configured to control the flow rate of refrigerant into the evaporator (120). Examples of the metering device (220) include a thermal expansion valve, a capillary tube, etc. In some embodiments, the metering device (220) is electrically coupled to a controller (124), and the controller (124) automatically controls its operation.

[0046] In some embodiments, the climate system (100) further includes a receiver / dryer (222) disposed at a refrigerant line (122-4) located between the condenser (118) and the evaporator (120). The receiver / dryer (222) is configured to temporarily store refrigerant or absorb moisture in the refrigerant, or to temporarily store refrigerant and absorb moisture in the refrigerant.

[0047] Now for reference Figure 3-5 These describe a first method (300) for controlling a climate system according to some embodiments of the present invention. For illustration, the first method (300) is described based on a climate system comprising a first compressor and a second compressor connected in parallel, i.e., the refrigerant inlets of the first and second compressors are fluidly connected to each other, and the refrigerant outlets of the first and second compressors are fluidly connected to each other. The climate system also includes a condenser disposed downstream of and fluidly connected to the first and second compressors, and a first blower disposed adjacent to the condenser and configured to blow air into the condenser. The climate system is installed in a vehicle to cool the vehicle's passenger compartment.

[0048] In some embodiments, the first method (300) is stored in a controller (such as...). Figure 1 and Figure 2 The controller (124) shown is controlled by instructions executed by the controller. In some embodiments, the first method (300) is controlled by instructions stored in a controller other than the controller. Figure 1 and Figure 2 Controlled by instructions executed by an electronic device other than the controller (124) shown.

[0049] In some embodiments, the first method (300) includes: receiving a desired temperature of the vehicle compartment and an ambient temperature outside the vehicle (step 305); monitoring the internal temperature of the vehicle compartment (step 310); determining whether the internal temperature is higher than the desired temperature (step 315); determining whether the internal temperature is higher than the ambient temperature (step 320); if the internal temperature exceeds both the desired temperature and the ambient temperature, turning on a first blower to expel internal air from the vehicle compartment (step 325); if the internal temperature is higher than the desired temperature but lower than or equal to the ambient temperature, determining whether the heat load of the vehicle compartment exceeds a first heat threshold (step 335); if the heat load of the vehicle compartment is less than or equal to the first heat threshold, turning on a first compressor or a second compressor (step 340); and if the heat load of the vehicle compartment exceeds the first heat threshold, turning on the first compressor and the second compressor (step 345).

[0050] In some embodiments, the climate system includes a second blower, or the climate system is coupled to an existing air conditioning system and the blower of the existing air conditioning system is used as the second blower of the climate system. In these embodiments, the first method (300) includes an additional or optional step (step 330): if the internal temperature exceeds the desired temperature and the atmospheric temperature, turning on the second blower to draw outside air or fresh air into the vehicle's passenger compartment. The first and second blowers may operate simultaneously, alternately, or independently.

[0051] In some embodiments, when the internal temperature drops to a desired temperature or when cooling is no longer required, the first method (300) automatically shuts down the first compressor and / or the second compressor (step 360). In some embodiments, before shutting down the first compressor and / or the second compressor, the first method (300) causes the first compressor to operate in a first low-speed range for a first low-speed period of time to allow compressor oil to return to the first oil sump, and / or before shutting down the second compressor, the first method causes the second compressor to operate in a second low-speed range for a second low-speed period of time to allow compressor oil to return to the second oil sump (step 355).

[0052] In some embodiments, each time the first compressor is about to be turned off or at regular intervals when the first compressor is about to be turned off, control is performed to operate the first compressor in a first low-speed range for a first low-speed period. Similarly, in some embodiments, each time the second compressor is about to be turned off or at regular intervals when the second compressor is about to be turned off, control is performed to operate the second compressor in a second low-speed range for a second low-speed period.

[0053] In some embodiments, the first method (300) further includes an additional or optional step 405 to determine whether compressor oil needs to be returned to one or more compressors. If it is determined that the compressor needs to have its oil returned, the first method (300) proceeds to step 355 to slow down the compressor (e.g., to run the compressor in a low-speed range for a period of time) before shutting it off in step 360. Otherwise, the first method (300) proceeds to step 360 to shut down the compressor. In some embodiments, this determination depends on how long the compressor has been running in a high-speed range. For example, in some embodiments, after the first compressor has run in a first high-speed range for a first high-speed period, the first compressor is run in a first low-speed range for a first low-speed period. After the second compressor has run in a second high-speed range for a second high-speed period, the second compressor is run in a second low-speed range for a second low-speed period.

[0054] In some embodiments, the second blower selectively communicates with the surrounding environment, the vehicle's fresh air system, or the vehicle's cabin fluid via a duct such as a pipe, conduit, channel, or tube. In some embodiments, a door is used to control airflow. In these embodiments, the first method (300) includes an additional or optional step 505, which involves opening or closing the door before turning on the second blower to allow it to blow outside or fresh air into the vehicle's cabin.

[0055] refer to Figure 6 This describes a second method (600) for controlling a climate system according to some embodiments of the present invention. For example, the second method (600) is described based on a climate system comprising a first compressor and a second compressor connected in parallel, i.e., the refrigerant inlets of the first and second compressors are fluidly connected to each other and the refrigerant outlets of the first and second compressors are fluidly connected to each other. The climate system also includes a condenser disposed downstream of and fluidly connected to the first and second compressors. The climate system is installed in a vehicle for cooling the vehicle's passenger compartment.

[0056] Similar to the first method (300), in some embodiments, the second method (600) is stored in a controller (e.g., Figure 1 and Figure 2 The second method (600) is controlled by instructions stored in and executed by the controller (124) shown. In some embodiments, the second method (600) is controlled by instructions stored in the controller (124) shown in the controller (124). Figure 1 and Figure 2 Controlled by instructions executed by an electronic device other than the controller (124) shown.

[0057] In some embodiments, the second method (600) includes: receiving a desired temperature of the vehicle compartment and an ambient temperature outside the vehicle (step 305); determining whether the heat load of the vehicle compartment exceeds a first heat threshold (step 335); if the heat load of the vehicle compartment is less than or equal to the first heat threshold, turning on a first compressor or a second compressor (step 340); if the heat load of the vehicle compartment exceeds the first heat threshold, turning on both the first compressor and the second compressor (step 345); and performing one or more of the following: operating the first compressor in a first low-speed range for a first low-speed period before shutting down the first compressor to allow compressor oil to return to a first oil tank; and operating the second compressor in a second low-speed range for a second low-speed period before shutting down the second compressor to allow compressor oil to return to a second oil tank (step 355).

[0058] In some embodiments, before operating the first and / or second compressors in a low-speed range (step 355), the second method (600) further includes one or more of the following additional or optional steps: determining whether compressor oil needs to be returned to the first compressor based on whether the first compressor has been operating in a first high-speed range and for how long; and determining whether compressor oil needs to be returned to the second compressor based on whether the second compressor has been operating in a second high-speed range and for how long (step 405). Based on the determination, in some embodiments, the second method (600) further includes one or more of the following: if the first compressor has been operating in the first high-speed range for a first high-speed period, operating the first compressor in a first low-speed range for a first low-speed period to return compressor oil to the first compressor; and if it is determined that the second compressor has been operating in the second high-speed range for a second high-speed period, operating the second compressor in the second low-speed range for a second low-speed period to return compressor oil to the second compressor.

[0059] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first compressor may be referred to as a second compressor without changing the meaning of the description, and similarly, a second compressor may be referred to as a first compressor, provided that all occurrences of “first compressor” are consistently renamed and all occurrences of “second compressor” are consistently renamed.

Claims

1. A climate system for cooling a vehicle compartment, comprising: The first compressor includes a first refrigerant inlet, a first refrigerant outlet, and a first oil tank; The second compressor includes a second refrigerant inlet, a second refrigerant outlet, and a second oil sump; wherein the first refrigerant inlet is fluidly connected to the second refrigerant inlet, and the first refrigerant outlet is fluidly connected to the second refrigerant outlet; the first oil sump is independent of the second oil sump, and the first oil sump and the second oil sump are not connected by any oil equalization system, not by a commonly used oil separator, and not by a commonly used suction manifold or conduit configured to return oil to the first oil sump and the second oil sump after oil has been separated from the refrigerant; A condenser, located downstream of the first compressor and the second compressor, is used to condense the refrigerant compressed by the first compressor and the second compressor; An evaporator, located downstream of the condenser, is used to evaporate the condensed refrigerant, wherein the evaporator is thermally coupled to the vehicle compartment to cool the compartment; A refrigerant line fluidly connecting the first compressor and the second compressor, the condenser and the evaporator to form a refrigerant circuit for circulating the refrigerant; and A controller, electrically coupled to the first compressor and the second compressor and configured to automatically and independently control the operation of the first compressor and the second compressor; The controller is configured to determine whether compressor oil needs to be returned to the first compressor based on whether the first compressor has been operating in a first high-speed range and for how long; in response to determining that compressor oil needs to be returned to the first compressor, the controller causes the first compressor to operate in a first low-speed range for a first low-speed period before shutting down the first compressor to allow compressor oil to be returned to the first oil tank; and in response to determining that compressor oil does not need to be returned to the first compressor, the controller shuts down the first compressor without causing the first compressor to operate in the first low-speed range for the first low-speed period.

2. The climate system according to claim 1, wherein, The controller is also configured to determine whether compressor oil needs to be returned to the second compressor based on whether the second compressor has been operating in the second high-speed range and for how long, and in response to determining that compressor oil needs to be returned to the second compressor, to operate the second compressor in the second low-speed range for a second low-speed period of time before shutting down the second compressor, so as to allow the compressor oil to be returned to the second oil tank.

3. The climate system according to claim 1, wherein, After the first compressor has been running at a high speed for a first high-speed period within the first high-speed range, the controller causes the first compressor to run at a low speed for a first low-speed period within the first low-speed range.

4. The climate system of claim 1 further includes a first flow control valve and a second flow control valve, the first flow control valve being disposed upstream of the first compressor and configured to selectively restrict or allow refrigerant flow to the first compressor, and the second flow control valve being disposed upstream of the second compressor and configured to selectively restrict or allow refrigerant flow to the second compressor.

5. The climate system according to claim 1, wherein, When the heat load of the carriage is equal to or less than the first threshold, the controller turns on the first compressor or the second compressor; when the heat load of the carriage exceeds the first threshold, the controller turns on both the first compressor and the second compressor.

6. The climate system according to claim 1, wherein, The first compressor is configured to be driven by an internal combustion engine, while the second compressor is an electrically driven compressor and is configured to operate when the vehicle's internal combustion engine is not running.

7. The climate system of claim 1 further includes a metering device disposed upstream of the evaporator and configured to control the flow rate of refrigerant entering the evaporator.

8. The climate system according to claim 7, wherein, The metering device is a thermal expansion valve or a capillary tube.

9. The climate system of claim 1 further includes a receiver / dryer disposed between the condenser and the evaporator and configured to temporarily store refrigerant, absorb moisture from the refrigerant, or both.

10. The climate system according to claim 1, wherein, The first low speed range is between 1500 and 6500 rpm, and the first low speed period is between 5 and 200 seconds.

11. The climate system according to claim 1, wherein, At least one of the first compressor and the second compressor is a rotary vane compressor.

12. The climate system according to claim 1, wherein, The first compressor and the second compressor have different capacities.

13. The climate system according to claim 1, further comprising: A sensor for measuring the ambient temperature outside the vehicle; A thermostat is used to receive the desired temperature and detect the internal temperature of the carriage. The controller is electrically coupled to the sensor and the thermostat, and is configured to control the operation of the first compressor and the second compressor based on the atmospheric temperature, the internal temperature and the desired temperature.

14. A method for controlling a climate system installed in a vehicle to cool a vehicle compartment, the climate system comprising a first compressor having a first oil tank and a second compressor having a second oil tank, the first oil tank being independent of the second oil tank, the first oil tank and the second oil tank being not connected via any oil leveling system, not connected via a conventional oil separator, and not connected via a conventional suction manifold, the method comprising: Determine whether it is necessary to return the compressor oil to the first compressor based on whether the first compressor has been operating in the first high-speed range and for how long. In response to determining that it is necessary to return compressor oil to the first compressor, the first compressor is operated in a first low speed range for a first low speed period before the first compressor is shut down, so as to allow the compressor oil to be returned to the first oil sump; as well as In response to determining that it is not necessary to return compressor oil to the first compressor, the first compressor is shut down without causing the first compressor to operate in the first low-speed range for the first low-speed period.

15. The method of claim 14, further comprising: Determine whether it is necessary to return the compressor oil to the second compressor based on whether the second compressor has been operating in the second high-speed range and for how long. as well as In response to determining that it is necessary to return the compressor oil to the second compressor, the second compressor is operated in the second low-speed range for a second low-speed period before being shut down, so as to allow the compressor oil to be returned to the second oil sump.

16. The method of claim 14, further comprising: Receive the desired temperature of the carriage and the ambient temperature outside the vehicle; Monitor the internal temperature of the carriage; And if the internal temperature exceeds both the desired temperature and the atmospheric temperature, the first blower is turned on to expel the internal air from the compartment.

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