Compressor oil return system for electric transportation refrigerating unit of new energy refrigerator car

Abstract

An oil return system for a compressor of an electric transportation refrigerating unit of a new energy refrigerator car comprises an oil separator, the compressor, a first-stage oil return capillary tube, an oil reservoir assembly, an oil return electromagnetic valve, a second-stage oil return capillary tube and a controller. An oil liquid outlet of the oil separator is connected with an oil inlet of the oil reservoir assembly through the first-stage oil return capillary tube, and an oil outlet of the oil reservoir assembly is connected to an air return pipeline of the compressor through two branch pipelines connected in parallel. The oil return electromagnetic valve and the second-stage oil return capillary tube are installed on two branch pipelines respectively, a control element capable of monitoring whether the running angle of a vehicle exceeds the safe inclination angle of the compressor or not is arranged on the oil reservoir assembly, and the controller is in signal connection with the control element and the oil return electromagnetic valve. The oil return device can ensure that the compressor can quickly return oil when the compressor exceeds a safe inclination angle.

Description

Technical Field

[0001] The present invention relates to the field of electric transport refrigeration units dedicated to new energy refrigerated trucks. Specifically, it relates to an oil return system for the compressor of an electric transport refrigeration unit for new energy refrigerated trucks. Background Art

[0002] At present, the transportation cold chain has received increasing attention. The whole people are more and more concerned about the safety of food, drugs, etc. The market in this field has also developed rapidly in recent years, and the industry has become more professional and refined. Especially in recent years, with the popularization of new energy refrigerated trucks, under the guidance of national policies and requirements such as energy conservation and emission reduction, the promotion intensity and popularization scope of new energy refrigerated trucks are gradually increasing. Therefore, the use of supporting electric transport refrigeration units is also increasing. The electric transport refrigeration unit has to move with the whole refrigerated truck. Whether it is daily movement behaviors such as turning, climbing slopes, or going downhill, it puts forward very high reliability requirements for the safe operation of the electric transport refrigeration unit.

[0003] Through the application of such products in recent years, especially through relevant analysis and research on the core component compressor in the electric transport refrigeration unit, it is found that one of the reasons for compressor damage is poor lubrication of the compressor. Of course, there are many reasons for poor lubrication. One of them is that when the electric transport refrigeration unit moves with the whole new energy refrigerated truck, especially during large-angle driving, large-angle driving includes climbing slopes, going downhill, turning, bumping, etc. As Figure 2 shown, after the compressor 2 in the electric transport refrigeration unit exceeds the safe tilt angle specified in the compressor specification book, a part of the connection part between the rotating shaft 13 and the bearing seat 14 of the compressor 2 will not be effectively lubricated. Under the condition that the compressor 2 rotates rapidly, the moving parts in the non-effectively lubricated part will have dry friction. The most unfavorable consequence is that the shaft is stuck, the compressor 2 cannot operate, the supporting frequency converter will report overload, the refrigeration system cannot operate, and the temperature in the refrigerated compartment cannot be guaranteed, which will cause damage to the goods in the compartment. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the prior art, and thus provide an oil return system for the compressor of an electric transport refrigeration unit for new energy refrigerated trucks. The present invention aims to solve the problem of safe oil return of the compressor during the large-angle driving of the electric transport refrigeration unit following the whole refrigerated truck, ensure that the compressor can quickly return oil when it exceeds the safe tilt angle, safely avoid this driving process, and after turning to normal driving, collect the excess lubricating oil in the refrigeration system through the normal oil return method.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A compressor oil return system for an electric transport refrigeration unit of a new energy refrigerated vehicle, including an oil separator and a compressor. The oil separator is installed on the exhaust pipe of the compressor. The oil separator is used to separate the refrigerant and lubricating oil output from the exhaust pipe of the compressor, so that the separated refrigerant flows through the refrigerant outlet of the oil separator to the refrigeration system, and the separated lubricating oil flows through the oil outlet of the oil separator to the suction pipe of the compressor for oil return. It also includes a first-stage oil return capillary, an oil storage assembly, an oil return solenoid valve, a second-stage oil return capillary and a controller. The oil outlet of the oil separator is connected to the oil inlet of the oil storage assembly through the first-stage oil return capillary. The oil outlet of the oil storage assembly is connected to the suction pipe of the compressor through two parallel branch pipelines. The oil return solenoid valve and the second-stage oil return capillary are respectively installed on the two branch pipelines. The oil return solenoid valve is a normally closed valve. A control element capable of monitoring whether the driving angle of the vehicle exceeds the safe inclination angle of the compressor is provided on the oil storage assembly. The controller is respectively connected to the control element and the oil return solenoid valve by signal; During the driving process of the vehicle, when the control element monitors that the driving angle of the vehicle exceeds the safe inclination angle of the compressor, the control element triggers the controller to control the oil return solenoid valve to open and close pulsatingly, so that the separated lubricating oil flows through the branch pipeline where the oil return solenoid valve is located to the suction pipe of the compressor for rapid oil return; otherwise, the oil return solenoid valve remains in the normally closed state, so that the separated lubricating oil flows through the branch pipeline where the second-stage oil return capillary is located to the suction pipe of the compressor for normal oil return.

[0006] Based on the above, the control element includes two oil level switches. The two oil level switches are respectively arranged on both sides of the middle part inside the oil storage assembly. The signal lines of the two oil level switches are connected in series for control and are connected to the controller by signal. During the normal driving process of the vehicle, the oil level in the oil storage assembly is within a suitable range in the middle, and both of the two oil level switches can contact the oil level and remain in the closed state. At this time, the oil return solenoid valve remains in the normally closed state. During the large-angle driving process of the vehicle, the oil level will be inclined relative to the oil storage assembly. When any one of the oil level switches cannot contact the oil level and is disconnected, the oil level switch triggers the controller to control the oil return solenoid valve to open and close pulsatingly to achieve rapid oil return.

[0007] Based on the above, the oil level switch is a mechanical float liquid level switch.

[0008] Based on the above, the control element includes an inclination angle sensor, which is horizontally arranged on the oil storage assembly, and the inclination angle sensor is communicatively connected to the controller; the inclination angle sensor sends angular coordinate parameters to the controller in real time. When the inclination angle sensor monitors that the offset of any azimuth angle coordinate exceeds the set offset, the inclination angle sensor triggers the controller to control the pulse opening and closing of the oil return solenoid valve to achieve rapid oil return, where the set offset is set according to the safe inclination angle of the compressor.

[0009] Based on the above, the inclination angle sensor communicates with the controller through the R485 communication protocol.

[0010] Based on the above, three sight glasses, namely an upper sight glass, a middle sight glass and a lower sight glass, are arranged on the oil storage assembly.

[0011] The present invention has prominent substantive features and remarkable progress compared with the prior art. Specifically, the present invention adds the oil storage assembly to the traditional oil return system. A control element capable of monitoring whether the driving angle of the vehicle exceeds the safe inclination angle of the compressor is arranged on the oil storage assembly. Then, in combination with the use of the first-stage oil return capillary tube, the second-stage oil return capillary tube and the oil return solenoid valve, it can be ensured that during the driving process of the vehicle, when the control element monitors that the driving angle of the vehicle exceeds the safe inclination angle of the compressor, the control element triggers the controller to control the pulse opening and closing of the oil return solenoid valve, so that the separated lubricating oil flows through the branch pipeline where the oil return solenoid valve is located to the return air pipeline of the compressor for rapid oil return, making up for the insufficient lubricating oil after the compressor exceeds the safe inclination angle, giving priority to ensuring the safe operation of the compressor, safely avoiding this driving process, and after turning to normal driving, collecting the excess lubricating oil in the refrigeration system through the normal oil return method to solve the problem of safe oil return of the compressor during the large-angle driving process of the current electric transport refrigeration unit following the refrigerated truck as a whole. Description of the Drawings

[0012] Figure 1 is a schematic structural diagram of the compressor oil return system for the electric transport refrigeration unit of a new energy refrigerated truck according to the present invention.

[0013] Figure 2 is a schematic diagram of poor lubrication of the current compressor during the large-angle driving process of the new energy refrigerated truck.

[0014] Figure 3 is a schematic structural and working principle diagram of the control element in the first embodiment of the present invention.

[0015] Figure 4 is a schematic structural diagram of the control element in the second embodiment of the present invention.

[0016] In the figure: 1. Oil separator; 2. Compressor; 3. First-stage oil return capillary tube; 4. Oil storage assembly; 5. Oil return solenoid valve; 6. Second-stage oil return capillary tube; 7. Exhaust pipe; 8. Oil sight glass; 9. Oil level switch; 10. Tilt angle sensor; 11. Oil separator outlet; 12. Suction pipe; 13. Rotating shaft; 14. Bearing housing. Detailed implementation manners

[0017] The technical solution of the present invention will be further described in detail below through specific implementation manners.

[0018] Considering that the electric transport refrigeration unit will move as a whole with the new energy vehicle, it will face road conditions such as vehicle uphill, climbing, and steering tilt. The oil level inside the compressor configured in the refrigeration unit will change accordingly. If the rotating components (rotating shaft 13 and bearing housing 14) of the high-speed operating compressor cannot be lubricated well, the compressor will be worn, which may cause the refrigeration unit to be unusable, and the safety of the whole vehicle's cargo cold chain transportation will also not be guaranteed. Although the compressor has an allowable tilt angle, most of them are in the range of 5 degrees to 15 degrees. When encountering special sections or hilly areas, once the tilt angle exceeds the safety range of the compressor, the probability of compressor wear will increase significantly.

[0019] Based on the above scenarios, the present invention proposes a compressor oil return system for an electric transport refrigeration unit of a new energy refrigerated truck, as Figure 1 shown, including an oil separator 1, a compressor 2, a first-stage oil return capillary tube 3, an oil storage assembly 4, an oil return solenoid valve 5, a second-stage oil return capillary tube 6, and a controller. The oil separator 1 is installed on the exhaust pipe 7 of the compressor 2. The oil separator 1 is used to separate the refrigerant and lubricating oil output from the exhaust pipe 7 of the compressor 2, so that the separated refrigerant flows through the refrigerant outlet of the oil separator 1 to the refrigeration system, and the separated lubricating oil flows through the oil outlet of the oil separator 1 and the first-stage oil return capillary tube 3 to the oil storage assembly 4. The oil outlet of the oil storage assembly 4 is a parallel pipeline, and the parallel pipeline includes a first branch pipeline and a second branch pipeline. The first branch pipeline is provided with the oil return solenoid valve 5, and the oil return solenoid valve 5 is a normally closed valve. The second branch pipeline is provided with the second-stage oil return capillary tube 6. The first branch pipeline and the second branch pipeline are connected in parallel and then connected to the suction pipe of the compressor 2. Finally, the separated lubricating oil will flow back to the compressor 2 along with the refrigerant, playing a role of lubricating and replenishing oil; the oil storage assembly 4 is provided with a control element that can monitor whether the driving angle of the vehicle exceeds the safe tilt angle of the compressor 2, and the controller is respectively connected to the control element and the oil return solenoid valve 5 in a signal manner.

[0020] The controller and the control element are not shown in Figure 1 either.

[0021] There are three oil sight glasses 8, upper, middle and lower, provided on the oil storage assembly 4. The height of the oil level in the oil storage assembly 4 can be conveniently observed through the three oil sight glasses 8.

[0022] During the normal driving of the electric transport refrigeration unit following the new energy refrigerated vehicle, after the lubricating oil is separated by the oil separator 1, it passes through the first-stage oil return capillary 3, the oil storage assembly 4 and the second-stage oil return capillary 6, and then returns to the compressor 2 following the refrigerant in the return air pipeline of the compressor 2, playing a role in normal lubricating oil replenishment.

[0023] During the large-angle driving of the electric transport refrigeration unit following the new energy refrigerated vehicle, where the large-angle driving includes climbing, descending, turning, bumping, etc. During the large-angle driving, when the control element monitors that the vehicle driving angle exceeds the safe tilt angle of the compressor 2, the control element triggers the controller to control the oil return solenoid valve 5 to adjust from the normally closed state to the pulsed opening and closing state. The lubricating oil flowing out of the oil storage assembly 4 will quickly return oil through the oil return solenoid valve 5 with less resistance. This is because compared with the second-stage oil return capillary 6, the resistance loss of the oil return solenoid valve 5 is lower, and the lubricating oil will preferentially flow through the oil return solenoid valve 5 to make up for the insufficient lubricating oil after the compressor 2 exceeds the safe tilt angle. The pulsed opening and closing of the oil return solenoid valve 5 can, on the one hand, achieve rapid oil return, and on the other hand, avoid the oil level from continuously dropping and being difficult to reset, enabling the oil level to be easily reset.

[0024] Embodiment 1 As Figure 3 shown, the control element includes two oil level switches 9, and the two oil level switches 9 are respectively arranged on both sides of the middle part inside the oil storage assembly 4. The two oil level switches 9 are in series signal control and are signal-connected to the controller; during the normal driving of the vehicle, the oil level in the oil storage assembly 4 is within the appropriate range in the middle, and both of the two oil level switches 9 can contact the oil level and remain in the closed state. At this time, the oil return solenoid valve 5 remains in the normally closed state; during the large-angle driving of the vehicle, the oil level will be inclined relative to the oil storage assembly 4. When any one of the two oil level switches 9 cannot contact the oil level and is disconnected, this oil level switch 9 triggers the controller to control the oil return solenoid valve 5 to open and close in a pulsed manner to achieve rapid oil return.

[0025] In an extreme case, during the normal driving of the vehicle, if the oil level is too low and the two oil level switches 9 are disconnected simultaneously, this will also trigger the controller to control the oil return solenoid valve 5 to open and close in a pulsed manner to achieve rapid oil return. If the control of the pulsed opening and closing of the oil return solenoid valve 5 is not restored for a long time, this indicates that there is a fault in this oil return system and the lubricating oil does not return oil normally, reminding the driver that this oil return system needs to be repaired.

[0026] The oil level switch 9 is a mechanical float liquid level switch.

[0027] Embodiment 2 As Figure 4 shown, the control element includes an inclination angle sensor 10, the inclination angle sensor 10 is horizontally arranged on the oil storage assembly 4, and the inclination angle sensor 10 is communicatively connected to the controller; the inclination angle sensor 10 sends angular coordinate parameters to the controller in real time through RS485 communication mode. When the inclination angle sensor 10 monitors that the offset of any azimuth coordinate exceeds the set offset, the inclination angle sensor 10 triggers the controller to send a control instruction to the oil return solenoid valve 5, thereby controlling the pulsed opening and closing of the oil return solenoid valve 5 to achieve rapid oil return, where the set offset is set according to the safe inclination angle of the compressor 2. The communication mode between the inclination angle sensor 10 and the controller is not limited to the RS485 communication protocol, and other communication modes can also be adopted. The inclination angle sensor 10 is powered by a low-voltage DC power supply mode.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: still modifications can be made to the specific embodiments of the present invention or equivalent replacements can be made to some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered by the scope of the technical solutions claimed in the present invention.

Claims

1. A compressor oil return system for an electric transport refrigeration unit of a new energy refrigerated vehicle, comprising an oil separator and a compressor, wherein the oil separator is installed on the exhaust pipeline of the compressor, and the oil separator is used to separate the refrigerant and lubricating oil output from the exhaust pipeline of the compressor, so that the separated refrigerant flows to the refrigeration system through the refrigerant outlet of the oil separator, and the separated lubricating oil flows to the return air pipeline of the compressor through the oil outlet of the oil separator for oil return, characterized in that: It also includes a first-stage oil return capillary, an oil reservoir assembly, an oil return solenoid valve, a second-stage oil return capillary and a controller. The oil outlet of the oil separator is connected to the oil inlet of the oil reservoir assembly through the first-stage oil return capillary, and the oil outlet of the oil reservoir assembly is connected to the return air pipeline of the compressor through two parallel branch pipelines. The oil return solenoid valve and the second-stage oil return capillary are respectively installed on the two branch pipelines. The oil return solenoid valve is a normally closed valve. The oil reservoir assembly is provided with a control element that can monitor whether the vehicle driving angle exceeds the safe tilt angle of the compressor. The controller is respectively connected to the control element and the oil return solenoid valve signal. During vehicle driving, when the control element monitors that the vehicle driving angle exceeds the safe tilt angle of the compressor, the control element triggers the controller to control the pulse opening and closing of the oil return solenoid valve, so that the separated lubricating oil flows to the return air pipeline of the compressor through the branch pipeline where the oil return solenoid valve is located for rapid oil return; otherwise, the oil return solenoid valve remains in a normally closed state, so that the separated lubricating oil flows to the return air pipeline of the compressor through the branch pipeline where the second-stage oil return capillary is located for normal oil return.

2. The oil return system for the compressor of the electric transport refrigeration unit of the new energy refrigerated truck according to claim 1 is characterized in that: The control element includes two oil level switches, which are respectively arranged on both sides of the middle part of the oil reservoir assembly, and the signal lines of the two oil level switches are controlled in series and connected to the controller signal; during normal driving of the vehicle, the oil level in the oil reservoir assembly is within a suitable range in the middle, and the two oil level switches can both contact the oil level and remain in a closed state, at which time the oil return solenoid valve remains in a normally closed state; during large-angle driving of the vehicle, the oil level will tilt relative to the oil reservoir assembly, and when any one of the oil level switches cannot contact the oil level and is disconnected, the oil level switch triggers the controller to control the pulse opening and closing of the oil return solenoid valve to achieve rapid oil return.

3. The oil return system for the compressor of the electric transport refrigeration unit of the new energy refrigerated vehicle according to claim 2 is characterized in that: The oil level switch is a mechanical float liquid level switch.

4. The oil return system for the compressor of the electric transport refrigeration unit of the new energy refrigerated vehicle according to claim 1 is characterized in that: The control element includes a tilt angle sensor, which is horizontally arranged on the oil reservoir assembly and is communicatively connected to the controller; the tilt angle sensor sends angular coordinate parameters to the controller in real time, and when the tilt angle sensor detects that any azimuth coordinate offset exceeds a set offset, the tilt angle sensor triggers the controller to control the oil return solenoid valve to open, thereby achieving rapid oil return, wherein the set offset is set according to the safe tilt angle of the compressor.

5. The oil return system for the compressor of the electric transport refrigeration unit of the new energy refrigerated vehicle according to claim 4 is characterized in that: The tilt angle sensor communicates with the controller via the R485 communication protocol.

6. The oil return system for the compressor of the electric transport refrigeration unit of the new energy refrigerated vehicle according to any one of claims 1 to 5, characterized in that: The oil reservoir assembly is provided with three oil sight glasses, namely, upper, middle and lower.

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