Air conditioning system oil return control method, automobile heat pump air conditioning system and electric automobile

Abstract

The application provides a kind of air conditioning system oil return control method, automobile heat pump air conditioning system and electric vehicle.The air conditioning system includes electric compressor, gas-liquid separator, evaporator and condenser connected by pipeline, and battery cooler connected in parallel with evaporator.The control method includes: monitoring the rotational speed of electric compressor;Monitoring the opening and closing state of battery cooler;Determine the current operating condition of electric compressor based on the rotational speed of electric compressor and the opening and closing state of battery cooler;Determine whether the current operating condition of electric compressor enters into predetermined condition;And when electric compressor enters into predetermined condition, then start emergency oil return strategy of electric compressor.The application can avoid damage to electric compressor caused by long-term operation of electric compressor in harsh conditions.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of automobile technology, and in particular to a method for controlling oil return of an air-conditioning system, an automobile heat pump air-conditioning system, and an electric vehicle. Background Art

[0002] With the continuous improvement of people's quality of life, the demand for automobiles has increased significantly in recent years. The rapid development of electric vehicles has fueled endless fantasies about the future of electric vehicles. Consequently, people have higher expectations for the in-car experience. Diversified interior spaces and the integration of new high-tech technologies have given cars a more technological feel. Heat pump air conditioning systems are one of the new high-tech features of recent years. Heat pump air conditioning systems add a built-in condenser to traditional air conditioning systems, allowing the air conditioner's electric compressor to generate heat. However, low-temperature heat pump systems place higher demands on the electric compressor and the system, particularly regarding oil return in the electric compressor.

[0003] Heat pump systems contain a gas-liquid separator, which accumulates large amounts of electric compressor oil. Furthermore, large, high-end vehicles with rear air conditioning systems have long air conditioning system piping, placing a significant strain on the oil return of the electric compressor. Typically, after dual air conditioning is activated, a large amount of residual oil accumulates in the gas-liquid separator and battery chiller, further complicating oil return from the electric compressor throughout the entire large air conditioning system. In extreme environments, to achieve high oil return from the electric compressor, additional oil or refrigerant is often added to the compressor to protect it from operating under extreme conditions. However, adding too much oil can make initial startup difficult, leading to a large accumulation of oil in the gas-liquid separator and severely impacting the cooling capacity of the entire air conditioning system. Without oil return, the electric compressor can experience dry grinding during operation, preventing the dynamic and static discs from being cooled. This leads to a continuous increase in the system's exhaust temperature, which in turn increases the intake superheat, further complicating oil return. Over time, this can cause wear on the dynamic and static discs and melting of the floating seal. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a control method for oil return of an air-conditioning system, an automobile heat pump air-conditioning system and an electric vehicle, which can prevent the electric compressor from operating under harsh working conditions for a long time and causing damage to the electric compressor body.

[0005] One aspect of an embodiment of the present application provides a method for controlling oil return in an air conditioning system, the air conditioning system comprising an electric compressor, a gas-liquid separator, an evaporator, and a condenser connected via pipelines, and a battery cooler connected in parallel with the evaporator. The control method comprises: monitoring the rotational speed of the electric compressor; monitoring the on / off state of the battery cooler; determining the current operating condition of the electric compressor based on the rotational speed of the electric compressor and the on / off state of the battery cooler; determining whether the current operating condition of the electric compressor has entered a predetermined operating condition; and, if the electric compressor has entered the predetermined operating condition, initiating an emergency oil return strategy for the electric compressor.

[0006] Furthermore, the determining whether the current operating condition of the electric compressor enters the predetermined operating condition includes: determining whether the current rotation speed of the electric compressor is less than a first predetermined rotation speed; and determining whether the battery cooler is currently in an off state.

[0007] Furthermore, when the current rotation speed of the electric compressor is less than the first predetermined rotation speed and the battery cooler is currently in an off state and continues to be in an off state for a first predetermined time, it is determined that the electric compressor enters the predetermined operating condition.

[0008] Furthermore, the first predetermined rotation speed is 1000 rpm, and the predetermined time is 30 minutes.

[0009] Furthermore, the emergency oil return strategy for starting the electric compressor includes: controlling the rotation speed of the electric compressor to increase to a second predetermined rotation speed; and controlling the battery cooler to be in an open state.

[0010] Furthermore, the second predetermined rotational speed is 1700 rpm.

[0011] Furthermore, the control method further includes: when the emergency oil return strategy lasts for a second predetermined time, shutting down the emergency oil return strategy and controlling the electric compressor to continue to operate in response to the requested speed.

[0012] Another aspect of the present application provides an automotive heat pump air conditioning system. The air conditioning system includes an electric compressor, a gas-liquid separator, an evaporator, and a condenser connected by pipelines, a battery cooler connected in parallel with the evaporator, and a controller. The controller is configured to obtain the rotational speed of the electric compressor and the on / off state of the battery cooler, determine whether the electric compressor has entered a predetermined operating condition based on the rotational speed of the electric compressor and the on / off state of the battery cooler, and activate an emergency oil return strategy for the electric compressor when the electric compressor enters the predetermined operating condition.

[0013] Furthermore, when the rotation speed of the electric compressor is less than a first predetermined rotation speed and the battery cooler is in an off state and continues to be in an off state for a first predetermined time, the controller determines that the electric compressor enters the predetermined operating condition.

[0014] Furthermore, when the electric compressor enters the predetermined operating condition, the controller controls the speed of the electric compressor to increase to a second predetermined speed, and controls the battery cooler to be in an open state to start the emergency oil return strategy.

[0015] Furthermore, the first predetermined rotational speed is 1000 rpm, the predetermined time is 30 minutes, and the second predetermined rotational speed is 1700 rpm.

[0016] Furthermore, the controller is further configured to control closing of the emergency oil return strategy when the emergency oil return strategy lasts for a second predetermined time, and control the electric compressor to continue to operate in response to the requested speed.

[0017] Furthermore, the automobile heat pump air conditioning system also includes a regulating valve connected in the pipeline between the condenser and the evaporator and a control valve connected to the battery cooler. The controller controls the opening and closing state of the battery cooler by controlling the opening and closing of the control valve.

[0018] Another aspect of the embodiments of the present application further provides an electric vehicle comprising the above-described automotive heat pump air conditioning system.

[0019] The embodiments of the present application solve the problems of internal wear of the electric compressor and melting of the sealing strip caused by the electric compressor running under low oil return conditions for a long time.

[0020] The embodiments of the present application have at least the following beneficial technical effects:

[0021] First, applicability: adding an electric compressor can better adapt to various harsh and low oil return working conditions;

[0022] Second, safety: When the electric compressor is detected to be at a low speed for a long time and a dangerous working condition is determined, the speed of the electric compressor is forcibly increased to allow the electric compressor to obtain more oil return, making the electric compressor safer;

[0023] Third, stability: Avoid adding too much electric compressor oil into the electric compressor, which will reduce the cooling capacity of the air-conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for controlling oil return of an air-conditioning system according to an embodiment of the present application.

[0025] Figure 2 These are the specific steps of a method for controlling oil return of an air-conditioning system according to a specific embodiment of the present application.

[0026] Figure 3 This is a simplified schematic diagram of an automotive heat pump air conditioning system according to one embodiment of the present application. DETAILED DESCRIPTION

[0027] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of devices consistent with certain aspects of the present application, as detailed in the appended claims.

[0028] The terms used in the embodiments of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by a person of ordinary skill in the art to which this application belongs. The terms "first," "second," and similar terms used in this specification and claims do not denote any order, quantity, or importance, but are simply used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation on quantity, but rather indicate the presence of at least one. "Multiple" or "several" means two or more. Unless otherwise indicated, terms such as "front," "rear," "lower," and / or "upper" are for convenience only and are not intended to limit to a single position or spatial orientation. Terms such as "include" or "comprising" mean that the elements or objects listed before "include" or "comprising" include the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. Terms such as "connected" or "connected" are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a," "an," "said," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0029] An embodiment of the present application provides a method for controlling oil return of an air-conditioning system. Figure 1 The flow chart of the oil return control method of an air conditioning system according to an embodiment of the present application is disclosed. The air conditioning system is, for example, an automobile heat pump air conditioning system 100. Figure 2As shown, the air conditioning system includes an electric compressor 101 , a gas-liquid separator 102 , an evaporator 103 and a condenser 104 connected by pipelines, and a battery cooler 105 connected in parallel with the evaporator 103 .

[0030] like Figure 1 As shown, a method for controlling oil return of an air-conditioning system according to an embodiment of the present application may include steps S11 to S15.

[0031] In step S11 , the rotation speed of the electric compressor 101 is monitored.

[0032] In step S12 , the open / close state of the battery cooler 105 is monitored.

[0033] In step S13 , the current operating state of the electric compressor 101 is determined based on the rotation speed of the electric compressor 101 monitored in step S11 and the open / close state of the battery cooler 105 monitored in step S12 .

[0034] In step S14, a determination is made as to whether the current operating condition of the electric compressor 101 has reached the predetermined operating condition. If so, the process proceeds to step S15. Otherwise, the process returns to steps S11 and S12 to continue monitoring the rotational speed of the electric compressor 101 and the on / off status of the battery cooler 105.

[0035] In some embodiments, step S14 of determining whether the current operating condition of the electric compressor 101 enters the predetermined operating condition may include: determining whether the current speed of the electric compressor 101 is less than a first predetermined speed; and determining whether the battery cooler 105 is currently in an off state.

[0036] In step S15 , when it is determined that the electric compressor 101 enters a predetermined operating condition, the emergency oil return strategy of the electric compressor 101 is started.

[0037] In some embodiments, when the current speed of the electric compressor 101 is less than a first predetermined speed and the battery cooler 105 is currently in the OFF state and continues to be in this state for a first predetermined time, it is determined that the electric compressor 101 has entered the predetermined operating state. The first predetermined speed can be reasonably set based on the actual oil return conditions of the electric compressor 101. In one embodiment, the first predetermined speed can be set to 1000 rpm, for example, and the predetermined time can be set to 30 minutes, for example.

[0038] In some embodiments, starting the emergency oil return strategy of the electric compressor 101 may include: controlling the rotation speed of the electric compressor 101 to increase to a second predetermined rotation speed; and controlling the battery cooler 105 to be in an ON state.

[0039] Because the heat pump air conditioning system has a large gas-liquid separator 102 and battery cooler 105, a large amount of electric compressor oil will accumulate in the gas-liquid separator 102 and battery cooler 105 during operation, resulting in a significant deterioration in the oil return of the electric compressor 101. The embodiment of the present application improves the control strategy of the electric compressor 101 on the vehicle side and adopts a special electric compressor 101 operation strategy to optimize the speed request of the electric compressor 101 from the vehicle side, thereby preventing the electric compressor 101 from operating for a long time under harsh working conditions and ultimately causing damage to the electric compressor 101.

[0040] The second predetermined speed can be reasonably set based on factors such as the actual oil return condition of the electric compressor 101 and passenger comfort. In one embodiment, the second predetermined speed can be set to 1700 rpm, for example. This can improve the oil return problem of the electric compressor 101 without significantly affecting passenger comfort.

[0041] In some embodiments, the air-conditioning system oil return control method of the present application may further include step S16 and step S17.

[0042] In step S16, it is determined whether the emergency oil return strategy has continued for a second predetermined time. If the result of the determination is "yes", the process proceeds to step S17. Otherwise, the process returns to step S15.

[0043] In step S17, if the emergency oil return strategy continues for a second predetermined time, the emergency oil return strategy may be disabled, and the electric compressor 101 may be controlled to continue operating at the requested speed. The second predetermined time may be appropriately set based on actual conditions. For example, the second predetermined time may be set to approximately 1 minute to avoid causing significant discomfort to passengers.

[0044] Figure 2 The specific steps of the oil return control method of the air conditioning system of a specific embodiment of the present application are disclosed. Figure 2 As shown, in step S21, the air conditioning system is started and the electric compressor 101 is running. During the operation of the electric compressor 101, the vehicle monitors the operating speed of the electric compressor 101.

[0045] In step S22, it is determined whether the electric compressor 101 is running at a low speed, for example, whether the speed of the electric compressor 101 is less than 1000 rpm. If the result of the determination is "yes", the process proceeds to step S23. Otherwise, the process proceeds to step S27.

[0046] In step S23, if the speed of the electric compressor 101 is less than 1000 rpm, the process proceeds to step S24 to determine whether the battery cooler 105 is in the off state. If the result of the determination is "yes", the process proceeds to step S27. Otherwise, the process proceeds to step S27.

[0047] In step S24, a determination is made as to whether the rotational speed of electric compressor 101 has been below 1000 rpm and battery cooler 105 has been off for at least 30 minutes. If so, the process proceeds to step S25. Otherwise, the process proceeds to step S27.

[0048] In step S25, if the electric compressor 101 is running at a low speed and the battery cooler 105 is off for a long period of time, the vehicle will initiate an emergency oil return strategy for the electric compressor 101. The emergency oil return strategy forcibly increases the speed of the electric compressor 101 to a second predetermined speed and opens the control valve 108 of the battery cooler 105. When the temperature fluctuation of the air conditioning outlet is within the range acceptable to passengers, the oil return of the electric compressor 101 is increased to a predetermined value.

[0049] In step S26, it is determined whether the emergency oil return strategy has been in effect for about 1 minute. If the emergency oil return strategy has been in effect for about 1 minute, the process proceeds to step S27. Otherwise, the emergency oil return strategy continues to be executed.

[0050] In step S27 , after the emergency oil return strategy lasts for about 1 minute, the emergency oil return strategy is exited to avoid causing discomfort to the passengers, and the electric compressor 101 continues to operate in response to the requested speed.

[0051] The following Table 1 shows the OCR (oil circulation rate) of the electric compressor 101 under some operating conditions, as shown below:

[0052] Table 1

[0053]

[0054] As can be seen from Table 1 above, under severe operating conditions, the OCR of electric compressor 101 is only approximately 0.2%. If electric compressor 101 continues to operate, it will inevitably be damaged. By adopting the emergency oil return strategy of the embodiment of the present application, the oil return rate of electric compressor 101 can be increased to 1.2%-1.5% after one minute, significantly improving the oil return rate.

[0055] The oil return control method of the air-conditioning system in the embodiment of the present application solves the problems of internal wear of the electric compressor 101 and melting of the sealing strip caused by the long-term operation of the electric compressor 101 under low oil return conditions.

[0056] The oil return control method for an air conditioning system according to an embodiment of the present application has at least the following beneficial technical effects:

[0057] First, applicability: adding the electric compressor 101 makes it more adaptable to various harsh and low oil return working conditions;

[0058] Second, safety: when the electric compressor 101 is detected to be at a low speed for a long time and a dangerous working condition is determined, the speed of the electric compressor 101 is forcibly increased to allow the electric compressor 101 to obtain more oil return, thereby improving the safety of the electric compressor 101;

[0059] Third, stability: avoid filling too much oil in the electric compressor 101, which will reduce the cooling capacity of the air-conditioning system.

[0060] The embodiment of the present application also provides an automobile heat pump air conditioning system 100 . Figure 3 A simplified schematic diagram of an automotive heat pump air conditioning system 100 according to an embodiment of the present application is disclosed. Figure 3 As shown, an automobile heat pump air conditioning system 100 according to an embodiment of the present application includes an electric compressor 101, a gas-liquid separator 102, an evaporator 103 and a condenser 104 connected by pipelines, a battery cooler 105 connected in parallel with the evaporator 103, and a controller 106.

[0061] The automotive heat pump air conditioning system 100 also includes a regulating valve 107 connected to the pipeline between the condenser 104 and the evaporator 103, and a control valve 108 connected to the battery cooler 105. The regulating valve 107 can be used to adjust the outlet temperature of the evaporator 103, managing the passenger area. The control valve 108 can be used to manage the battery area. The controller 106 can control the opening and closing of the battery cooler 105 by controlling the opening and closing of the control valve 108.

[0062] The controller 106 can receive the speed signal fed back from the electric compressor 101 and the opening and closing status signal fed back from the battery cooler 105, thereby obtaining the speed of the electric compressor 101 and the opening and closing status of the battery cooler 105. Then, the controller 106 can determine whether the electric compressor 101 enters the predetermined working condition based on the speed of the electric compressor 101 and the opening and closing status of the battery cooler 105, and start the emergency oil return strategy of the electric compressor 101 when the electric compressor 101 enters the predetermined working condition.

[0063] In some embodiments, when the speed of the electric compressor 101 is less than a first predetermined speed and the battery cooler 105 is in an off state for a first predetermined time, the controller 106 may determine that the electric compressor 101 has entered a predetermined operating state. The first predetermined speed may be set, for example, to 1000 rpm, and the predetermined time may be set, for example, to 30 minutes.

[0064] In some embodiments, when the electric compressor 101 enters a predetermined operating state, the controller 106 may increase the speed of the electric compressor 101 to a second predetermined speed and control the battery cooler 105 to be in an open state to initiate the emergency oil return strategy. The second predetermined speed may be set to, for example, 1700 rpm.

[0065] In some embodiments, the controller 106 is further configured to control the emergency oil return strategy to be turned off when the emergency oil return strategy lasts for a second predetermined time, and control the electric compressor 101 to continue to operate in response to the requested speed.

[0066] The automobile heat pump air conditioning system 100 of the embodiment of the present application can solve the problems of internal wear of the electric compressor 101 and melting of the sealing strip caused by the electric compressor 101 running under low oil return conditions for a long time.

[0067] The present application also provides an electric vehicle, which includes the automotive heat pump air conditioning system 100 described in the above embodiments.

[0068] The electric vehicle of the embodiment of the present application has substantially similar beneficial technical effects to the automotive heat pump air conditioning system 100 described above, and therefore, they will not be described in detail here.

[0069] The above is a detailed introduction to the air-conditioning system oil return control method, automobile heat pump air-conditioning system and electric vehicle provided in the embodiments of the present application. This article uses specific examples to illustrate the air-conditioning system oil return control method, automobile heat pump air-conditioning system and electric vehicle in the embodiments of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application and is not intended to limit the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the spirit and principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications should also fall within the scope of protection of the claims attached to the present application.

Claims

1. A method for controlling oil return in an air conditioning system, wherein the air conditioning system comprises an electric compressor, a gas-liquid separator, an evaporator, and a condenser connected by pipelines, and a battery cooler connected in parallel with the evaporator, characterized in that: The control method includes: monitoring the rotational speed of the electric compressor; monitoring the on / off status of the battery cooler; determining a current operating condition of the electric compressor based on a rotation speed of the electric compressor and an on / off state of the battery cooler; Determining whether the current operating condition of the electric compressor has entered a predetermined operating condition; and When the electric compressor enters the predetermined working condition, the emergency oil return strategy of the electric compressor is started. The emergency oil return strategy for starting the electric compressor includes: controlling the rotation speed of the electric compressor to increase to a second predetermined rotation speed; and controlling the battery cooler to be in an open state.

2. The control method according to claim 1, wherein: The determining whether the current operating condition of the electric compressor has entered a predetermined operating condition includes: Determining whether the current rotation speed of the electric compressor is less than a first predetermined rotation speed; and It is determined whether the battery cooler is currently in an off state.

3. The control method according to claim 2, wherein: When the current rotation speed of the electric compressor is less than the first predetermined rotation speed and the battery cooler is currently in an off state and continues to be in an off state for a first predetermined time, it is determined that the electric compressor enters the predetermined operating state.

4. The control method according to claim 3, wherein: The first predetermined rotation speed is 1000 rpm, and the first predetermined time is 30 minutes.

5. The control method according to claim 1, wherein: The second predetermined rotation speed is 1700 rpm.

6. The control method according to claim 1, wherein: Also includes: When the emergency oil return strategy lasts for a second predetermined time, the emergency oil return strategy is turned off, and the electric compressor is controlled to continue to operate in response to the requested speed.

7. An automobile heat pump air conditioning system, characterized in that: The system comprises an electric compressor, a gas-liquid separator, an evaporator and a condenser connected by pipelines, a battery cooler connected in parallel with the evaporator, and a controller, wherein the controller is used to obtain the rotation speed of the electric compressor and the on / off state of the battery cooler, and to determine whether the electric compressor has entered a predetermined operating condition based on the rotation speed of the electric compressor and the on / off state of the battery cooler, and to activate an emergency oil return strategy of the electric compressor when the electric compressor enters the predetermined operating condition. When the electric compressor enters the predetermined operating condition, the controller controls the rotation speed of the electric compressor to increase to a second predetermined rotation speed, and controls the battery cooler to be in an open state to start the emergency oil return strategy.

8. The automotive heat pump air conditioning system according to claim 7, wherein: When the rotation speed of the electric compressor is less than a first predetermined rotation speed and the battery cooler is in an off state and continues to be in an off state for a first predetermined time, the controller determines that the electric compressor enters the predetermined operating state.

9. The automotive heat pump air conditioning system according to claim 8, wherein: The first predetermined rotation speed is 1000 rpm, the first predetermined time is 30 minutes, and the second predetermined rotation speed is 1700 rpm.

10. The automotive heat pump air conditioning system according to claim 7, wherein: The controller is further configured to control closing of the emergency oil return strategy when the emergency oil return strategy lasts for a second predetermined time, and control the electric compressor to continue operating in response to the requested speed.

11. The automotive heat pump air conditioning system according to claim 7, wherein: It also includes a regulating valve connected to the pipeline between the condenser and the evaporator and a control valve connected to the battery cooler. The controller controls the opening and closing state of the battery cooler by controlling the opening and closing of the control valve.

12. An electric vehicle, characterized in that: The vehicle heat pump air conditioning system comprises the vehicle heat pump air conditioning system according to any one of claims 7 to 11.

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