Two-stage supercharging variable-frequency methanol pump and working method thereof

Abstract

The invention relates to the technical field of pumps, in particular to a two-stage supercharging variable-frequency methanol pump and a working method thereof. The methanol pump comprises a shell, the shell comprises a liquid inlet bin, a motor bin, a liquid outlet bin and an exhaust bin which are sequentially arranged, and a roller pump, a motor unit, a vane pump and an exhaust unit are sequentially installed in the four bins. The motor unit comprises a motor rotor and a motor stator, the two ends of the motor rotor are connected with the roller pump and the vane pump respectively, the liquid inlet bin, the motor bin and the liquid outlet bin are communicated, and the motor stator is provided with a cooling channel for liquid circulation; the exhaust unit comprises a liquid outlet pipe, a liquid conveying pipe and a liquid return pipe, one end of the liquid outlet pipe is communicated with the liquid outlet bin, the liquid conveying pipe is connected to the outer side of the liquid outlet pipe in a sleeving mode, one end of the liquid return pipe is communicated with the liquid conveying pipe, and the other end of the liquid return pipe extends out of the exhaust bin. The efficiency and reliability of the supply system are improved, meanwhile, the manufacturing cost and noise are reduced, and the service life of the pump is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of pumps, and in particular to a two-stage booster variable frequency methanol pump and a working method thereof. Background Art

[0002] As a clean energy, methanol is increasingly used in engines. The methanol pump is a key device used in the engine methanol supply system to transport methanol from the storage tank to the engine. The performance of the methanol pump directly affects the working efficiency and stability of the methanol engine.

[0003] At present, methanol pumps on the market mainly adopt internal gear pumps, external gear pumps, roller pumps, impeller pumps and other modes. These pumps have their own characteristics in working principles, but they generally have some common problems. For example, although methanol pumps in gear pump mode can provide greater pressure, they are noisy, severely worn, have a short life, and have complex manufacturing processes and high costs. Methanol pumps in roller pump and impeller pump modes are insufficient in providing sufficient pressure and flow, and cannot meet the needs of high-power engines. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the embodiments of the present invention is to provide a two-stage booster variable frequency methanol pump to improve the efficiency and reliability of the supply system, while reducing manufacturing costs and noise, extending the service life of the pump, and achieving a lightweight design to meet the development needs of methanol engines.

[0005] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A two-stage booster variable frequency methanol pump comprises a shell, the shell comprises a liquid inlet bin, a motor bin, a liquid outlet bin and an exhaust bin which are arranged in sequence, and a roller pump, a motor unit, a vane pump and an exhaust unit are installed in the four bins in sequence; the motor unit comprises a motor rotor and a motor stator, and the two ends of the motor rotor are respectively connected to the roller pump and the vane pump, the liquid inlet bin, the motor bin and the liquid outlet bin are connected, and the motor stator is provided with a cooling channel for liquid circulation; the exhaust unit comprises a liquid outlet pipe, a liquid infusion pipe and a liquid return pipe, one end of the liquid outlet pipe is connected to the liquid outlet bin, the liquid infusion pipe is sleeved on the outside of the liquid outlet pipe, one end of the liquid return pipe is connected to the liquid infusion pipe, and the other end extends out of the exhaust bin.

[0007] Optionally, the liquid inlet bin is equipped with a liquid inlet pipe, the other end of the liquid inlet pipe is connected to the liquid storage box, and the end of the liquid return pipe extending out of the exhaust bin is also connected to the liquid storage box.

[0008] Optionally, the motor stator is embedded in the inner wall of the motor compartment, the motor rotor is located at the center of the motor stator, and both ends of the motor rotor are connected to the roller pump and the vane pump through a coupling.

[0009] Optionally, a pressure sensor is provided on the infusion tube, and the pressure sensor is used to detect the pressure in the methanol pump in real time. An exhaust solenoid valve is provided on the liquid return pipe, and the exhaust solenoid valve is used to open and close the liquid return pipe.

[0010] Optionally, the two-stage boost variable frequency methanol pump further includes a heating element, and the heating element is located in the motor compartment and installed on the inner wall of the motor compartment.

[0011] Optionally, the two-stage boost variable frequency methanol pump further includes an electronic control unit, which is connected to the motor unit, the exhaust unit and the heating unit, and is also connected to the vehicle engine ECU.

[0012] An embodiment of the present invention also provides a working method of the two-stage booster variable frequency methanol pump as described above, including: the motor unit rotates to drive the roller pump and the vane pump to rotate, wherein the roller pump is the first-stage booster pump, and the vane pump is the second-stage booster pump. The two-stage pump starts working and establishes pressure inside the pump. The two pumps synchronously establish pressure and realize pressure superposition and self-priming and output of the liquid.

[0013] Optionally, active exhaust before engine start: Liquid and gas are discharged from the liquid return pipe under pressure and flow back to the liquid storage tank.

[0014] Optionally, active pressure relief during engine operation: When the pressure in the pump reaches a threshold, part of the liquid is discharged from the liquid return pipe and flows back to the liquid storage tank.

[0015] Optionally, during operation, real-time monitoring and analysis is performed based on the collected pressure data. When there is no pressure in the pump, the pressure is less than the minimum threshold, or the pressure is higher than the maximum threshold, an abnormal alarm signal is sent to the vehicle or engine CAN line.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0017] The methanol pump of the present invention can be used to pump methanol fuel and become a methanol pump for a high-power engine. By superimposing the roller pump and the vane pump, the superimposed pressure of the two-stage pump is realized, and the problem of insufficient pressure and flow of the methanol pump in a single pump mode is solved. At the same time, when the methanol liquid flows through the cooling channel of the motor stator, the motor can be continuously cooled, and the residual heat temperature of the motor also heats up the methanol liquid in the warehouse. Moreover, the active exhaust before the engine starts and the pressure relief protection during operation are completed by the exhaust unit. In addition, the vane pump can smooth the pulsation generated by the roller pump, and has the advantages of low noise, low pulsation, not easy to wear, long service life, low manufacturing cost, and easy implementation. It can be applied to commercial vehicles, commercial vehicles, construction machinery, ships, high-power generator sets and other scenes.

[0018] Methanol is a volatile liquid with strong corrosiveness. In order to reduce the corrosion of methanol to the methanol pump body, motor, supply pipeline, etc., there is no methanol in the pump body and pipeline when the methanol pump stops working. Therefore, each time the methanol pump is powered on, an active exhaust operation is completed to discharge the gas in the pump body and pipeline to avoid the engine start-up affected by cavitation. The exhaust process is also the process of fully preheating the methanol liquid in the front-end pipe. Each exhaust process is also the process of cleaning the particulate matter and condensate in the methanol pump and pipeline, reducing the damage to the engine-related systems caused by particulate matter and condensate.

[0019] The methanol pump is equipped with an active pressure relief function. When the pressure inside the pump reaches the set upper pressure limit, the electronic control unit actively opens the exhaust solenoid valve to relieve the pressure. This can avoid damage to the methanol pump and problems with the methanol pipeline caused by excessive pressure inside the methanol pump, avoid the occurrence of safety accidents, and ensure that the methanol pump operates safely within a controllable range.

[0020] The methanol pump is equipped with an automatic heating element, which can automatically heat the methanol liquid within the set temperature range, increase the temperature of the methanol liquid, and facilitate the cold start and smooth operation of the engine. The power supply to the heating element is controlled by the methanol pump electronic control unit. After the engine enters normal operation (such as 10 minutes), the electronic control stops supplying power to the heating element; when the ambient temperature is low, continuous heating can be set.

[0021] The methanol pump's electronic control unit communicates with the vehicle's ECU via CAN. The methanol pump's electronic control unit receives instructions from the vehicle's ECU and enters normal operation when the engine is started. It can adjust the motor's speed by frequency conversion according to the calibrated threshold value based on the vehicle or engine's operating conditions to achieve outputs of different pressures and flows, thereby achieving energy saving while meeting the engine's power requirements.

[0022] Advantages of additional aspects of the present invention will be given in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In addition, the spacing or size between the components is exaggerated to show the positions of the components, and the schematic diagram is only used for illustration.

[0024] Figure 1 Schematic diagram of a two-stage booster frequency conversion methanol pump provided by an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of a roller pump provided by an embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of a vane pump provided by an embodiment of the present invention;

[0027] In the figure: 1, housing; 11, liquid inlet tank; 12, motor tank; 13, liquid outlet tank; 14, exhaust tank; 15, liquid inlet pipe; 2, roller pump; 3, motor unit; 31, motor stator; 32, cooling channel; 33, motor rotor; 4, vane pump; 5, exhaust unit; 51, pressure sensor; 52, liquid outlet pipe; 53, liquid infusion pipe; 54, exhaust solenoid valve; 55, liquid return pipe; 6, heating element; 7, electronic control unit; DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Terminology explanation:

[0030] Roller pump: a methanol pump consisting of a pump body, a shaft, and a distribution plate. Two rows of rollers are arranged along the circumference of the pump body, and the pump body cavity or shaft is eccentric relative to the rotation line.

[0031] Vane pump: The vanes in the motor rotor slots are in contact with the pump housing (motor stator ring), pressing the sucked liquid from the oil inlet side to the oil discharge side.

[0032] Example 1

[0033] In order to solve the technical problems mentioned in the background technology, this embodiment proposes a two-stage booster frequency conversion methanol pump, such as Figure 1As shown. The methanol pump is an external type, and the structure adopts a cylindrical straight-through integrated type, including a housing 1, the housing 1 includes a liquid inlet bin 11, a motor bin 12, a liquid outlet bin 13 and an exhaust bin 14 arranged in sequence, and a roller pump 2, a motor unit 3, a vane pump 4 and an exhaust unit 5 are installed in the four bins in sequence; the motor unit 3 includes a motor rotor 33 and a motor stator 31, and the two ends of the motor rotor 33 are respectively connected to the roller pump 2 and the vane pump 4, the liquid inlet bin 11, the motor bin 12 and the liquid outlet bin 13 are connected, and the motor stator 31 is provided with a cooling channel 32 for liquid circulation; the exhaust unit 5 includes a liquid outlet pipe 52, a liquid infusion pipe 53 and a liquid return pipe 55, one end of the liquid outlet pipe 52 is connected to the liquid outlet bin 13, the liquid infusion pipe 53 is sleeved on the outside of the liquid outlet pipe 52, one end of the liquid return pipe 55 is connected to the liquid infusion pipe 53, and the other end extends out of the exhaust bin 14.

[0034] The roller pump 2 and the vane pump 4 are respectively located in the liquid inlet bin 11 and the liquid outlet bin 13, the former is the first-stage booster pump, and the latter is the second-stage booster pump; the motor unit 3 is located in the motor bin 12, and is composed of a motor rotor 33 and a motor stator 31. The motor rotor 33 is connected to the roller pump 2 and the vane pump 4 through a coupling, driving them to rotate and work to complete the liquid pressurization work; the exhaust unit 5 includes a liquid outlet pipe 52, a liquid infusion pipe 53 and a liquid return pipe 55, which are responsible for the reflux and exhaust of the liquid.

[0035] The methanol pump of the present invention can be used to pump methanol fuel and become a methanol pump for high-power engines. The methanol pump is divided into two stages of pressurization, the first stage is a roller pump 2, and the second stage is a vane pump 4. The two pumps are respectively installed at both ends of the motor rotor 33; the motor is controlled by an electronic control and can be speed-controlled and frequency-controlled to adjust the pressure and flow. During operation, the motor rotor 33 drives the roller pump 2 and the vane pump 4 to operate, gradually increase the liquid pressure through two-stage pressurization, and finally output the pressurized liquid. The liquid flows into the pump body from the liquid inlet tank 11, and after being pressurized by the roller pump 2 and the vane pump 4, the liquid is discharged from the liquid outlet tank 13.

[0036] like Figure 2 As shown, the roller pump 2 can be designed to use five-column or four-column modes according to the flow rate of the methanol pump, and the required materials are all anti-corrosion materials. Figure 3 As shown, the vane pump 4 can adopt a mode in which grooves are set around the impeller disk, and the required materials are all anti-corrosion materials. The flow rates of the roller pump 2 and the vane pump 4 must match, and the flow rate of the vane pump 4 must be greater than the flow rate of the roller pump 2 to avoid the problem of liquid trapped in the pump. Of course, it is understandable that other pump methods can also be used to achieve the secondary pressurization process, such as the impeller plane compartment mode.

[0037] The first-stage pump and the second-stage pump are independent pumps, which are connected to the motor rotor 33 through a coupling. The bearings used can be engineering nylon sleeves or ceramic bearings. Fluororubber sealing accessories can be selected for shaft sealing to achieve isolation of the two pumps in the liquid inlet bin 11 and the liquid outlet bin 13 from the motor bin 12. The connection between the housing and the two pumps can be embedded or flanged, and the exhaust bin 14 and the liquid outlet bin 13 are welded together. The connection can be made of fluororubber multi-layer sealing, or an inner layer of fluororubber and an outer layer of epoxy resin coating to prevent methanol leakage or seepage.

[0038] The liquid inlet tank 11 is connected to the motor tank 12, and one end of the liquid inlet tank 11 is provided with a liquid inlet pipe 15 connected to the external methanol storage tank, and the other end of the liquid inlet tank 11 is provided with a liquid outlet leading to the motor tank 12, and the pressurized methanol liquid enters the motor tank 12. The liquid outlet tank 13 is connected to the motor tank 12, and one end of the liquid outlet tank 13 is provided with a liquid inlet connected to the motor tank 12, and the pressurized methanol liquid enters the liquid outlet tank 13 through this port. The liquid outlet tank 13 has a liquid outlet, and the other end of the liquid outlet tank 13 is provided with a liquid outlet connected to the exhaust unit 5, and the liquid return pipe 55 extends out of the exhaust tank 14 and communicates with the methanol storage tank.

[0039] The motor is a permanent magnet motor, and the motor stator 31 is embedded in the inner wall of the motor bin 12 and fixed by glue. The motor rotor 33 is installed on the bearing seat connected to the motor stator 31 to ensure the coaxiality of the motor rotor 33. The two ends of the motor rotor 33 are connected to the roller pump 2 of the liquid inlet bin 11 and the vane pump 4 of the motor bin 12 through a coupling and output power. The two pumps are arranged at both ends of the motor rotor 33, which can also balance the power of the motor. Because methanol is corrosive, the motor rotor 33 of the motor is made of stainless steel, and the motor rotor 33 and the motor stator 31 are both treated with anti-corrosion. The motor is controlled by the electronic control unit 7. When the engine ignition key is turned to "NO", the electronic control unit 7 supplies power to the motor. Variable frequency and speed can be achieved under the control of the electronic control unit 7.

[0040] The exhaust unit 5 mainly performs two functions: active exhaust and active pressure relief. The exhaust chamber 14 is circular, and the liquid outlet pipe 52 and the infusion pipe 53 form a sleeve form, with a cavity between the two to receive the methanol liquid and gas that are backwashed under pressure. A pressure sensor 51 is arranged on the infusion pipe 53 to monitor the pressure in the pump in real time, and the electronic control unit 7 determines the working state of the methanol pump according to the detected pressure value. In addition, an exhaust solenoid valve 54 is arranged on the liquid return pipe 55 to control the on and off of the liquid return pipe 55. The electromagnetic on-off valve is controlled by the electronic control unit 7 and is in a closed state when the power is off. The exhaust solenoid valve 54 can automatically adjust the channel for liquid reflux according to the change of the pressure in the pump, ensure the smooth reflux of liquid in the system and the timely discharge of gas, and avoid excessive gas being trapped in the system to affect the working efficiency of the pump.

[0041] Because methanol has a low flash point (12 degrees), when the ambient temperature is lower than 20 degrees (settable) and the engine is cold started, preheating methanol is beneficial to the combustion of the engine. Based on this, the two-stage boost frequency conversion methanol pump also includes a heating element 6, which is located in the motor compartment 12 and installed on the inner wall of the motor compartment 12. The heating element 6 is a stainless steel self-controlled heating element 6 with a temperature switch. When the temperature of the methanol liquid is lower than the set temperature, the heating element 6 starts heating automatically. The heating element 6 is controlled by the electronic control unit 7, and the electronic control unit 7 supplies power to the heating element 6. When the engine ignition key is turned to "NO", the electronic control unit 7 supplies power to the heating unit. 10 minutes after the engine starts running, the temperature of the engine itself has entered a high temperature state. At this time, the electronic control stops supplying power to the heating element 6, and the heating element 6 stops heating. According to the needs and the space of the motor compartment 12, one or more heating elements 6 can be provided, embedded in the inner wall of the shell in a round belt manner.

[0042] The methanol pump is provided with an independent electronic control unit 7. The electronic control unit 7 communicates with the engine (the whole vehicle) through the CAN line, and the electronic control unit 7 receives CAN instructions to control the operation of the methanol pump. The functions of the electronic control unit 7 include: controlling the power on and off of the methanol pump motor, adjusting the motor speed, collecting real-time signals from the pressure sensor 51, controlling the power on and off of the heating unit, and controlling the opening and closing of the exhaust electromagnetic on-off valve; receiving CAN line instructions, sending methanol pump operation information such as motor speed, pressure, etc. to the CAN line, analyzing and processing the collected information, and sending operation information and alarm information to the CAN line. The electronic control unit 7 is installed in the waterproof housing 1, and a heat sink can be installed on the outside of the housing 1.

[0043] Methanol pump anti-corrosion requirements:

[0044] The pump body and connecting parts are made of corrosion-resistant stainless steel. The bearings used can be engineering nylon sleeves or ceramic bearings. The shaft seal can be made of corrosion-resistant fluororubber sealing accessories. The infusion pipeline uses a corrosion-resistant fluororubber double-arm tube.

[0045] The shell adopts a double seal design. The first seal is sealed with an end face fluororubber sealing ring. However, considering the leakage of methanol liquid and avoiding other hidden dangers caused by leakage, a concave belt is designed at the outer seam of the shell, and epoxy resin and glass fiber are used for secondary sealing.

[0046] In summary, the present embodiment relates to a methanol pump for methanol fuel and a high-power engine, which is an integrated lightweight design. The methanol pump is divided into two-stage boosting, the first stage is a roller pump 2, the second stage is a vane pump 4, and a permanent magnet motor is used. The two pumps are respectively installed at both ends of the motor rotor 33; the motor is controlled by an electronic control, and the speed and frequency can be adjusted to adjust the pressure and flow. A heating element 6 is provided in the methanol pump to control the temperature and heat the methanol liquid. The methanol pump is provided with an exhaust unit 5 to complete the active exhaust before the engine starts and the pressure relief protection during operation. The electronic control unit 7 completes the driving motor, collects the pressure signal, controls the heating element 6, controls the exhaust and pressure relief, and abnormal alarms.

[0047] Example 2

[0048] This embodiment provides a working method of the two-stage booster frequency conversion methanol pump described in Embodiment 1:

[0049] When the engine ignition key is turned to "ON", the electronic control unit 7 supplies power to the methanol pump motor, and the two-stage pump starts to work and builds up pressure in the pump. The roller pump 2 is the first-stage booster pump, and the vane pump 4 is the second-stage booster pump. The two pumps simultaneously build up pressure and achieve pressure superposition and self-priming and output of methanol liquid. This working mode ensures the high efficiency of the two-stage boosting. Through the combined action of the roller pump 2 and the vane pump 4, the gradual superposition of pressure and the stable control of liquid flow are achieved.

[0050] Active exhaust: When the engine ignition key is turned to "ON", the electronic control unit 7 supplies power to the electromagnetic on-off valve, the electromagnetic on-off valve opens, and the methanol liquid and gas are discharged from the liquid return pipe 55 under the action of pressure and flow back to the methanol storage tank. The exhaust time can be set to 5 seconds each time it is started, and the electronic control controls the electromagnetic on-off valve to close when the exhaust is completed. This process avoids the gas in the liquid affecting the normal operation of the pump during the startup process, and ensures that the pump body can reach the predetermined working state immediately after startup.

[0051] Active pressure relief: During the operation of the methanol pump, the electronic control unit 7 collects data from the pressure sensor 51 in real time and performs detection and analysis in real time. When the pressure in the methanol pump reaches the set upper limit (such as 600kPa), the electronic control unit 7 supplies power to the exhaust electromagnetic on-off valve, the electromagnetic on-off valve opens, and part of the methanol liquid is discharged into the exhaust liquid return pipe to achieve active pressure relief. The opening size of the electromagnetic on-off valve can be opened according to the set value. This function can prevent the pressure in the pump from being too high, protect the system from overload, and ensure that the pump runs efficiently while avoiding system damage.

[0052] During the operation of the methanol pump, the electronic control unit 7 performs real-time monitoring and analysis based on the collected pressure data, and sends abnormal alarm signals to the vehicle or engine CAN line for abnormal conditions such as no pressure, low pressure, and high pressure in the pump. Through this monitoring and alarm mechanism, system abnormalities can be discovered and handled in a timely manner to ensure the normal operation of the pump body and reduce the risk of system failure.

[0053] When the methanol pump stops running, the pressure in the pump and pipeline is lost, and the methanol liquid in the methanol pump and pipeline is automatically unloaded and returned to the methanol storage tank under the action of gravity, reducing the corrosion of the pump body, components, and pipelines caused by long-term storage of methanol. Therefore, the methanol pump should be installed vertically.

[0054] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A two-stage booster frequency conversion methanol pump, characterized in that: The housing comprises a liquid inlet compartment, a motor compartment, a liquid outlet compartment and an exhaust compartment which are arranged in sequence, and a roller pump, a motor unit, a vane pump and an exhaust unit are installed in the four compartments in sequence; The motor unit comprises a motor rotor and a motor stator, two ends of the motor rotor are respectively connected to a roller pump and a vane pump, the liquid inlet bin, the motor bin and the liquid outlet bin are connected, and the motor stator is provided with a cooling channel for liquid circulation; The exhaust unit includes a liquid outlet pipe, an infusion pipe and a liquid return pipe, one end of the liquid outlet pipe is connected to the liquid outlet bin, the infusion pipe is sleeved on the outside of the liquid outlet pipe, one end of the liquid return pipe is connected to the infusion pipe, and the other end extends out of the exhaust bin.

2. The two-stage booster frequency conversion methanol pump according to claim 1, characterized in that: The liquid inlet bin is provided with a liquid inlet pipe, the other end of the liquid inlet pipe is communicated with the liquid storage box, and one end of the liquid return pipe extending out of the exhaust bin is also communicated with the liquid storage box.

3. The two-stage booster frequency conversion methanol pump according to claim 1, characterized in that: The motor stator is embedded in the inner wall of the motor compartment, the motor rotor is located at the center of the motor stator, and two ends of the motor rotor are connected to the roller pump and the vane pump through a coupling.

4. The two-stage booster frequency conversion methanol pump according to claim 1, characterized in that: The infusion tube is provided with a pressure sensor, and the pressure sensor is used to detect the pressure in the methanol pump in real time. The liquid return pipe is provided with an exhaust solenoid valve, and the exhaust solenoid valve is used to open and close the liquid return pipe.

5. The two-stage booster frequency conversion methanol pump according to claim 1, characterized in that: The two-stage boost frequency conversion methanol pump also includes a heating element, which is located in the motor compartment and installed on the inner wall of the motor compartment.

6. The two-stage booster frequency conversion methanol pump according to claim 1, characterized in that: The two-stage boost frequency conversion methanol pump also includes an electronic control unit, which is connected to the motor unit, the exhaust unit and the heating unit, and is also connected to the vehicle engine ECU.

7. A working method of a two-stage booster frequency conversion methanol pump as claimed in any one of claims 1 to 6, characterized in that: include: The motor unit rotates and drives the roller pump and the vane pump to rotate, wherein the roller pump is the first-stage booster pump and the vane pump is the second-stage booster pump. The two-stage pump starts working and builds up pressure inside the pump. The two pumps build up pressure synchronously and realize pressure superposition and self-priming and output of the liquid.

8. The working method according to claim 7, characterized in that: Active exhaust before engine start: Liquid and gas are discharged from the liquid return pipe under pressure and flow back to the liquid storage tank.

9. The working method according to claim 7, characterized in that: Active pressure relief during engine operation: When the pressure in the pump reaches a threshold, part of the liquid is discharged from the liquid return pipe and flows back to the liquid storage tank.

10. The working method according to claim 7, characterized in that: During operation, real-time monitoring and analysis are performed based on the collected pressure data. When there is no pressure in the pump, the pressure is less than the minimum threshold, or the pressure is higher than the maximum threshold, an abnormal alarm signal is sent to the vehicle or engine CAN line.

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