Pump booster type LNG (Liquefied Natural Gas) cold energy utilization system and control method thereof

Abstract

The invention discloses a pump booster type LNG cold energy utilization system and a control method thereof, the LNG cold energy utilization system comprises an LNG storage tank, a cooler, a gas supply mechanism and a booster pump, the cooler comprises a cooling shell, a first heat dissipation pipe and a second heat dissipation pipe, and the first heat dissipation pipe and the second heat dissipation pipe are arranged in the cooling shell; the gas supply mechanism comprises a vaporizer and a buffer tank, and a third heat dissipation pipe and a fourth heat dissipation pipe are arranged in the vaporizer. The system has the beneficial effects that by arranging the booster pump, the system can effectively suck LNG gas in the buffer tank into the LNG storage tank, so that the pressure in the LNG storage tank is increased, and the pressure in the LNG storage tank can be kept stable when a vehicle runs; meanwhile, according to the system, cold energy is provided for the refrigeration air conditioner through a second heat dissipation pipe in the cooler, recycling of LNG cold energy is achieved, and the energy utilization efficiency of the whole system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of LNG vehicle gas supply systems, and in particular to a pump-pressurized LNG cold energy utilization system and a control method thereof. Background Art

[0002] In the gas supply system of liquefied natural gas (LNG) vehicles, ensuring the stability of the internal pressure of the LNG tank plays a decisive role in ensuring the continuous and stable supply of fuel. As a key component of fuel storage, the internal pressure of the LNG tank directly affects the fuel supply efficiency and the stability of vehicle operation. Therefore, it is particularly urgent to solve the problem of how to effectively maintain the stability of the internal pressure of the LNG tank.

[0003] At present, natural supercharging and buffer tank integrated pump supercharging are mainly used in LNG vehicle gas supply systems. The natural supercharging scheme uses the pressure difference generated by the gasification of LNG itself for supercharging. Although this scheme is simple and low in cost, it has the problem of slow supercharging and is difficult to meet the fuel needs of vehicles under high load or emergency conditions.

[0004] In contrast, the buffer tank integrated pump boosting solution uses equipment such as electric pumps to increase the pressure in the LNG bottle. The boosting speed is faster and can better meet the vehicle's fuel needs.

[0005] During the natural supercharging process, the cold energy generated by LNG gasification is mainly dissipated into the air through the finned tubes, resulting in energy waste. Although the buffer tank integrated electric pump supercharging solution uses part of the cold energy for engine cooling and heat dissipation, after the engine cooling demand is met, the remaining cold energy still cannot be effectively utilized by the system. Especially in summer, when the vehicle needs additional air conditioning, if this part of the cold energy can be used reasonably, it will be able to further improve the energy efficiency of LNG vehicles. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and propose a pump-boosted LNG cold energy utilization system to solve the technical problems in the prior art that the gas supply system of LNG vehicles is difficult to ensure the stability of the pressure in the LNG bottle when the vehicle is driving and the LNG cold energy utilization is insufficient.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The present invention provides a pump-pressurized LNG cold energy utilization system, comprising: LNG storage tanks; A cold take-out device, comprising a cold take-out housing and a first heat dissipation pipe and a second heat dissipation pipe arranged in the cold take-out housing, one end of the first heat dissipation pipe is connected to the LNG storage tank, and the second heat dissipation pipe is used to supplement cold for the refrigeration air conditioner; A gas supply mechanism, comprising a vaporizer and a buffer tank, wherein a third heat dissipation pipe and a fourth heat dissipation pipe are arranged in the vaporizer, two ends of the third heat dissipation pipe are respectively connected to the inlet of the LNG storage tank and the buffer tank, and two ends of the fourth heat dissipation pipe are respectively connected to the other end of the first heat dissipation pipe and the inlet of the buffer tank; and, A boosting pump, an inlet of which is connected to the buffer tank, and an outlet of which is connected to the LNG storage tank.

[0008] In some embodiments, the LNG storage tank is provided with a liquid outlet and a gas inlet.

[0009] In some embodiments, the outlet of the boost pump is connected to the air inlet via a first connecting pipe.

[0010] In some embodiments, the cooling device further includes a second connecting tube, one end of which is connected to the liquid outlet, and the other end of which is connected to one end of the first heat dissipation tube.

[0011] In some embodiments, the cooling device further includes a third connecting tube, one end of the third connecting tube is connected to the other end of the first heat dissipation tube, and the other end of the third connecting tube is connected to one end of the fourth heat dissipation tube.

[0012] In some embodiments, the vaporizer also includes a fourth connecting pipe and a fifth connecting pipe, one end of the fourth connecting pipe is connected to the liquid outlet, the other end of the fourth connecting pipe is connected to one end of the third heat dissipation pipe, one end of the fifth connecting pipe is connected to the other end of the third heat dissipation pipe, the other end of the fifth connecting pipe is connected to the inlet of the buffer tank, a first control valve is provided on the fifth connecting pipe, and the outlet of the buffer tank is used to connect to the air intake end of the engine.

[0013] In some embodiments, the vaporizer further includes a sixth connecting pipe, one end of which is connected to the other end of the fourth heat dissipation pipe, the other end of which is connected to the inlet of the buffer tank, and a second control valve is provided on the sixth connecting pipe.

[0014] In some embodiments, the pump-boosting LNG cold energy utilization system further includes a controller, which is electrically connected to the LNG storage tank, the boosting pump, the first control valve, and the second control valve.

[0015] In some embodiments, the pump-boosted LNG cold energy utilization system also includes a heat exchange mechanism, which includes a circulating pump, a plate exchanger, a cold core and a temperature sensor. The inlet of the circulating pump is connected to one end of the second heat dissipation pipe, and the outlet of the circulating pump is connected to one end of the plate exchanger. The plate exchanger is connected to the refrigeration air conditioner and is used to provide cold energy for the refrigeration air conditioner. The other end of the plate exchanger is connected to one end of the cold core, and the other end of the cold core is connected to the other end of the second heat dissipation pipe. The temperature sensor is used to detect the temperature of the medium in the heat exchange mechanism.

[0016] The present invention also provides a control method for a pump-pressurized LNG cold energy utilization system, comprising: S1. When the vehicle is powered on and refrigeration and air conditioning are not needed, the LNG liquid in the LNG storage tank enters the third heat dissipation pipe in the vaporizer and, after being vaporized, enters the buffer tank and is then discharged from the buffer tank for use by the engine; S2. When the vehicle is powered on and the refrigeration and air conditioning is needed, the LNG liquid in the LNG storage tank first enters the first heat dissipation pipe in the refrigeration housing, and performs heat exchange with the medium in the refrigeration housing, so that the temperature of the medium in the refrigeration housing is reduced, and then flows to the fourth heat dissipation pipe in the vaporizer for vaporization, and then enters the buffer tank, and then is discharged from the buffer tank for use by the engine; at the same time, the second heat dissipation pipe in the refrigeration device is used to supplement the refrigeration and air conditioning; S3. When the pressure in the LNG storage tank is lower than the preset pressure, the booster pump starts working to extract the gaseous LNG gas in the buffer tank and pump it to the LNG storage tank, thereby increasing the pressure in the LNG storage tank continuously. The pressure in the LNG storage tank increases until it reaches the preset pressure, and then the booster pump stops working.

[0017] Compared with the prior art, the pump-boosting LNG cold energy utilization system provided by the present invention has the following beneficial effects: by setting a boosting pump, the system can effectively pump the LNG gas in the buffer tank into the LNG storage tank, thereby increasing the pressure in the LNG storage tank. The operation of the boosting pump can be automatically adjusted according to the pressure in the LNG storage tank. When the pressure is lower than the preset pressure, the boosting pump starts to work and increases the pressure in the storage tank, so that the pressure in the LNG storage tank is always maintained at the preset pressure, so that even when the vehicle is driving, the pressure in the LNG storage tank can always remain stable; at the same time, the system provides cold energy for the refrigeration and air conditioning through the second heat dissipation pipe in the cooler, thereby realizing the recycling of cold energy. This not only reduces the energy consumption of the refrigeration and air conditioning, but also improves the energy utilization efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a pump-pressurized LNG cold energy utilization system provided by one embodiment of the present invention; Figure 2 yes Figure 1 The structural diagram of the LNG storage tank; Figure 3 yes Figure 1 The control flow diagram of the pump-boosting LNG cold energy utilization system; Explanation of the reference numerals: 1-LNG storage tank, 11-liquid outlet, 12-air inlet, 2-cooler, 21-cooling shell, 22-first heat dissipation pipe, 23-second heat dissipation pipe, 24-second connecting pipe, 25-third connecting pipe, 3-gas supply mechanism, 31-vaporizer, 311-third heat dissipation pipe, 312-fourth heat dissipation pipe, 313-fifth heat dissipation pipe, 314-fourth connecting pipe, 315-fifth connecting pipe, 316-sixth connecting pipe, 32-buffer tank, 4-boosting pump, 41-first connecting pipe, 5-refrigeration air conditioner, 6-heat exchange mechanism, 61-circulating pump, 62-plate exchanger, 63-cold core, V1-first control valve, V2-second control valve, T3-temperature sensor. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In order to solve the technical problems in the prior art that the gas supply system of LNG vehicles is difficult to ensure the stability of the pressure in the LNG bottle when the vehicle is in motion and the insufficient utilization of LNG cold energy, the present invention provides a pump-boosting LNG cold energy utilization system, which can ensure the stability of the pressure in the LNG bottle when the vehicle is in motion and can fully utilize the LNG cold energy.

[0021] See also Figure 1-Figure 3 , Figure 1 This is a structural schematic diagram of a pump-pressurized LNG cold energy utilization system in one embodiment of the present invention. The pump-pressurized LNG cold energy utilization system includes an LNG storage tank 1, a cold extractor 2, an air supply mechanism 3 and a booster pump 4.

[0022] The LNG storage tank 1 is equipped with a pressure detection unit, which can detect the pressure inside the LNG storage tank 1 .

[0023] The cold take-out device 2 includes a cold take-out housing 21 and a first heat dissipation pipe 22 and a second heat dissipation pipe 23 disposed in the cold take-out housing 21. One end of the first heat dissipation pipe 22 is connected to the LNG storage tank 1, and the second heat dissipation pipe 23 is used to supplement cold for the refrigeration air conditioner 5. The gas supply mechanism 3 includes a vaporizer 31 and a buffer tank 32. The vaporizer 31 is provided with a third heat dissipation pipe 311 and a fourth heat dissipation pipe 312. The two ends of the third heat dissipation pipe 311 are respectively connected to the LNG storage tank 1 and the inlet of the buffer tank 32, and the two ends of the fourth heat dissipation pipe 312 are respectively connected to the other end of the first heat dissipation pipe 22 and the inlet of the buffer tank 32. It should be understood that when the engine is working, the medium in the vaporizer 31 exchanges heat with the engine, thereby cooling the engine. Conversely, the heat generated by the engine can also heat the medium in the vaporizer 31, so that the medium in the vaporizer 31 is maintained at a higher temperature, thereby realizing the gasification function.

[0024] The inlet of the boosting pump 4 is communicated with the buffer tank 32 , and the outlet thereof is communicated with the LNG storage tank 1 .

[0025] When in use, when the vehicle is powered on, if the refrigeration and air conditioning 5 is not needed, the LNG liquid in the LNG storage tank directly enters the third heat dissipation pipe 311 in the vaporizer 31 for gasification, then enters the buffer tank 32 for buffering and voltage stabilization, and finally is discharged from the buffer tank 32 for use by the engine; when the vehicle is powered on, if the refrigeration and air conditioning 5 is needed, the LNG liquid in the LNG storage tank first enters the first heat dissipation pipe 22 in the cold taker 2, and performs heat exchange with the medium in the cold taker housing, so that the temperature of the medium in the cold taker housing is reduced. Subsequently, the medium enters the fourth heat dissipation pipe 312 in the vaporizer 31 for gasification, then enters the buffer tank 32 for buffering and voltage stabilization, and finally is discharged from the buffer tank 32 for use by the engine. At the same time, the second heat dissipation pipe 23 in the cooler 2 is used to supplement the cooling for the refrigeration air conditioner 5, so as to realize the recovery and utilization of cold energy; when the pressure in the LNG storage tank is lower than the LNG saturation pressure, the booster pump works to extract the gaseous LNG fuel in the buffer tank and pump it to the LNG storage tank, thereby increasing the pressure in the LNG storage tank continuously, and the pressure in the LNG storage tank increases until the LNG saturation pressure is reached, and then the booster pump stops working.

[0026] The technical solution provided by the present invention is that by setting a booster pump, the system can effectively pump the LNG gas in the buffer tank into the LNG storage tank, so that the pressure in the LNG storage tank is increased. The operation of the booster pump can be automatically adjusted according to the pressure in the LNG storage tank. When the pressure is lower than the LNG saturation pressure, the booster pump starts to work and increases the pressure in the storage tank, so that the pressure in the LNG storage tank is always maintained at the LNG saturation pressure. In this way, even when the vehicle is driving, the pressure in the LNG storage tank can always remain stable; at the same time, the system provides cold energy for the refrigeration and air conditioning through the second heat dissipation pipe in the cooler, realizing the recycling of cold energy. This not only reduces the energy consumption of the refrigeration and air conditioning, but also improves the energy utilization efficiency of the entire system.

[0027] In one embodiment, see Figure 1 and Figure 2 The LNG storage tank 1 is provided with a liquid outlet 11 and a gas inlet 12 .

[0028] In one embodiment, see Figure 1 and Figure 2 The outlet of the boost pump 4 is connected to the air inlet 12 via a first connecting pipe 41 .

[0029] In one embodiment, see Figure 1 and Figure 2 The cooler 2 also includes a second connecting tube 24 and a third connecting tube 25, one end of the second connecting tube 24 is connected to the liquid outlet 11, the other end of the second connecting tube 24 is connected to one end of the first heat dissipation tube 22, one end of the third connecting tube 25 is connected to the other end of the first heat dissipation tube 22, and the other end of the third connecting tube 25 is connected to one end of the fourth heat dissipation tube 312.

[0030] In one embodiment, see Figure 1 and Figure 2 The vaporizer 31 of the air supply mechanism 3 also includes a fourth connecting pipe 314 and a fifth connecting pipe 315. One end of the fourth connecting pipe 314 is connected to the liquid outlet 11, and the other end of the fourth connecting pipe 314 is connected to one end of the third heat dissipation pipe 311. One end of the fifth connecting pipe 315 is connected to the other end of the third heat dissipation pipe 311, and the other end of the fifth connecting pipe 315 is connected to the inlet of the buffer tank 32. The fifth connecting pipe 315 is provided with a first control valve V1, and the outlet of the buffer tank 32 is used to communicate with the air intake end of the engine.

[0031] In one embodiment, see Figure 1 and Figure 2 The vaporizer 31 of the air supply mechanism 3 also includes a sixth connecting pipe 316, one end of the sixth connecting pipe 316 is connected to the other end of the fourth heat dissipation pipe 312, and the other end of the sixth connecting pipe 316 is connected to the inlet of the buffer tank 32, and the sixth connecting pipe 316 is provided with a second control valve V2.

[0032] In one embodiment, see Figure 1 and Figure 2 The pump-boosted LNG cold energy utilization system also includes a heat exchange mechanism 6, which includes a circulation pump 61, a plate exchanger 62, a cold core 63 and a temperature sensor T3. The inlet of the circulation pump 61 is connected to one end of the second heat dissipation pipe 23, and the outlet of the circulation pump 61 is connected to one end of the plate exchanger 62. The plate exchanger 62 is connected to the refrigeration air conditioner 5 and is used to provide cold energy for the refrigeration air conditioner 5. The other end of the plate exchanger 62 is connected to one end of the cold core 63, and the other end of the cold core 63 is connected to the other end of the second heat dissipation pipe 23. The temperature sensor T3 is used to detect the temperature of the medium in the heat exchange mechanism 6.

[0033] In one of the embodiments, the pump-boosting LNG cold energy utilization system further includes a controller, which is electrically connected to the LNG storage tank, the boosting pump, the first control valve and the second control valve for achieving control.

[0034] The present invention also provides a control method for a pump-pressurized LNG cold energy utilization system, comprising: S1. When the vehicle is powered on and the refrigeration and air conditioning 5 is not needed, the first control valve V1 is opened and the second control valve V2 is closed. The LNG liquid in the LNG storage tank 1 enters the third heat dissipation pipe 311 in the vaporizer 31 of the gas supply mechanism 3, and after being gasified, enters the buffer tank 32 through the first control valve V1, and is then discharged from the buffer tank 32 for use by the engine; S2. The vehicle is powered on. When the refrigeration air conditioner 5 is needed, the first control valve V1 is closed and the second control valve V2 is opened. The LNG liquid in the LNG storage tank 1 first enters the first heat dissipation pipe 22 of the cooler 2 and exchanges heat with the medium in the cool shell 21 of the cooler 2, so that the temperature of the medium in the cool shell 21 is reduced. The LNG liquid then flows to the fourth heat dissipation pipe 312 in the vaporizer 31 of the gas supply mechanism 3 for vaporization, and then enters the buffer tank 32 through the second control valve V2, and is then discharged from the buffer tank 32 for use by the engine. At the same time, the second heat dissipation pipe 23 in the cooler 2 is used to supplement the cooling for the refrigeration air conditioner 5. Specifically, the circulation pump 61 drives the heat medium to circulate in the second heat dissipation pipe 23, the plate exchanger 62 and the cold core 63, so that the cold energy of the medium in the cold taking shell 21 of the cold taking device 2 is transferred to the air conditioning refrigeration system through the plate exchanger 62. When the cold energy of LNG is insufficient, the plate exchanger 62 is further cooled by the refrigeration air conditioner 5 according to the temperature setting of T3, thereby realizing energy-saving use of air conditioning. It is estimated that the use of air conditioning in summer can reduce the fuel consumption of the whole vehicle by about 3% to 5%; S3. When the pressure in the LNG storage tank is lower than the LNG saturation pressure, the booster pump starts working to extract the gaseous LNG in the buffer tank and pump it to the LNG storage tank, thereby increasing the pressure in the LNG storage tank continuously. The pressure in the LNG storage tank increases until it reaches the LNG saturation pressure, and then the booster pump stops working.

[0035] Please refer to Figure 3 , the control strategy of the above principle is described as follows: When the vehicle is powered on: (the following controls are performed simultaneously without any particular order) (1) First, the liquid level sensor LG in the LNG storage tank, the gas cylinder pressure sensor P1, and the buffer tank pressure sensor P2 perform status detection and measurement. The controller converts each measurement value into a digital signal and sends it to the vehicle through a message to display the corresponding liquid level and pressure, as well as the corresponding instrument display and alarm strategy; (2) The booster pump is powered on. When the following conditions are met at the same time: ① the monitoring temperature is between -t1 and t2℃, ② the voltage is between (U1 and U2)V, ③ the current is ≤i1A, and ④ the controller receives the pressure in the gas cylinder ≤Pa Mpa, the booster pump starts working. Otherwise, the booster pump stops working. If the continuous boosting time exceeds t3 and the gas cylinder pressure still does not reach the pressure Pb, the booster pump enters the protection state and stops working for t4 minutes. After that, the booster pump restarts and enters the next judgment to repeat the above pump start process judgment. (3) When the ambient temperature is greater than a certain temperature t5, the solenoid valve V2 opens and V1 closes, and the discharged LNG is cooled through the cooler to be used by the air conditioning system. On the contrary, when the temperature is less than a certain temperature t5, the solenoid valve V2 closes and V1 opens; when the cooler temperature is ≥ t6, the solenoid valve V2 opens and V1 closes; when the cooler temperature is continued to be ≤ -t6 °C, the solenoid valve V2 closes and V1 opens. The opening and closing of the solenoid valves V1 and V2 are determined according to the ambient temperature and the medium temperature cycle in the cooler, so as to continuously use the cold energy of the engine burning LNG for refrigeration and air conditioning as needed; (4) When the air conditioning command needs to be turned on, the liquid outlet of the LNG storage tank has been cooled in advance by storing cold through the cooler, that is, the second control valve is opened in advance and the first control valve is closed.

[0036] When the vehicle is running, the working status (time, pressure, current, voltage, temperature) is uploaded to TBOX via CAN, which can remotely monitor the working status of parts and achieve precise control of gas cylinder pressure and real-time monitoring and diagnosis.

[0037] The technical solution provided by the present invention is that by setting a booster pump, the system can effectively pump the LNG gas in the buffer tank into the LNG storage tank, so that the pressure in the LNG storage tank is increased. The operation of the booster pump can be automatically adjusted according to the pressure in the LNG storage tank. When the pressure is lower than the LNG saturation pressure, the booster pump starts to work and increases the pressure in the storage tank, so that the pressure in the LNG storage tank is always maintained at the LNG saturation pressure. In this way, even when the vehicle is driving, the pressure in the LNG storage tank can always remain stable; at the same time, the system provides cold energy for the refrigeration and air conditioning through the second heat dissipation pipe in the cooler, realizing the recycling of cold energy. This not only reduces the energy consumption of the refrigeration and air conditioning, but also improves the energy utilization efficiency of the entire system.

[0038] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A pump-pressurized LNG cold energy utilization system, characterized in that: include: LNG storage tanks; A cold take-out device, comprising a cold take-out housing and a first heat dissipation pipe and a second heat dissipation pipe arranged in the cold take-out housing, one end of the first heat dissipation pipe is connected to the LNG storage tank, and the second heat dissipation pipe is used to supplement cold for the refrigeration air conditioner; A gas supply mechanism, comprising a vaporizer and a buffer tank, wherein a third heat dissipation pipe and a fourth heat dissipation pipe are arranged in the vaporizer, two ends of the third heat dissipation pipe are respectively connected to the inlet of the LNG storage tank and the buffer tank, and two ends of the fourth heat dissipation pipe are respectively connected to the other end of the first heat dissipation pipe and the inlet of the buffer tank; and, A boosting pump, an inlet of which is connected to the buffer tank, and an outlet of which is connected to the LNG storage tank.

2. The pump-pressurized LNG cold energy utilization system according to claim 1, characterized in that: The LNG storage tank is provided with a liquid outlet and a gas inlet.

3. The pump-pressurized LNG cold energy utilization system according to claim 2 is characterized in that: The outlet of the boost pump is communicated with the air inlet via a first connecting pipe.

4. The pump-pressurized LNG cold energy utilization system according to claim 2, characterized in that: The cooling device further includes a second connecting pipe, one end of which is connected to the liquid outlet, and the other end of which is connected to one end of the first heat dissipation pipe.

5. The pump-pressurized LNG cold energy utilization system according to claim 2, characterized in that: The cooling device further includes a third connecting pipe, one end of which is connected to the other end of the first heat dissipation pipe, and the other end of the third connecting pipe is connected to one end of the fourth heat dissipation pipe.

6. The pump-pressurized LNG cold energy utilization system according to claim 2, characterized in that: The vaporizer also includes a fourth connecting pipe and a fifth connecting pipe, one end of the fourth connecting pipe is connected to the liquid outlet, the other end of the fourth connecting pipe is connected to one end of the third heat dissipation pipe, one end of the fifth connecting pipe is connected to the other end of the third heat dissipation pipe, the other end of the fifth connecting pipe is connected to the inlet of the buffer tank, a first control valve is provided on the fifth connecting pipe, and the outlet of the buffer tank is used to communicate with the air intake end of the engine.

7. The pump-pressurized LNG cold energy utilization system according to claim 6, characterized in that: The vaporizer further includes a sixth connecting pipe, one end of which is connected to the other end of the fourth heat dissipation pipe, and the other end of which is connected to the inlet of the buffer tank. A second control valve is provided on the sixth connecting pipe.

8. The pump-pressurized LNG cold energy utilization system according to claim 7, characterized in that: The pump-boosting LNG cold energy utilization system further includes a controller, which is electrically connected to the LNG storage tank, the boosting pump, the first control valve, and the second control valve.

9. The pump-pressurized LNG cold energy utilization system according to claim 1, characterized in that: The pump-boosted LNG cold energy utilization system also includes a heat exchange mechanism, which includes a circulation pump, a plate exchanger, a cold core and a temperature sensor. The inlet of the circulation pump is connected to one end of the second heat dissipation pipe, and the outlet of the circulation pump is connected to one end of the plate exchanger. The plate exchanger is connected to the refrigeration air conditioner and is used to provide cold energy for the refrigeration air conditioner. The other end of the plate exchanger is connected to one end of the cold core, and the other end of the cold core is connected to the other end of the second heat dissipation pipe. The temperature sensor is used to detect the temperature of the medium in the heat exchange mechanism.

10. A control method for a pump-pressurized LNG cold energy utilization system according to any one of claims 1 to 9, characterized in that: include: S1. When the vehicle is powered on and refrigeration and air conditioning are not needed, the LNG liquid in the LNG storage tank enters the third heat dissipation pipe in the vaporizer and, after being vaporized, enters the buffer tank and is then discharged from the buffer tank for use by the engine; S2. When the vehicle is powered on and the refrigeration and air conditioning is needed, the LNG liquid in the LNG storage tank first enters the first heat dissipation pipe in the refrigeration housing, and performs heat exchange with the medium in the refrigeration housing, so that the temperature of the medium in the refrigeration housing is reduced, and then flows to the fourth heat dissipation pipe in the vaporizer for vaporization, and then enters the buffer tank, and then is discharged from the buffer tank for use by the engine; at the same time, the second heat dissipation pipe in the refrigeration device is used to supplement the refrigeration and air conditioning; S3. When the pressure in the LNG storage tank is lower than the preset pressure, the booster pump starts working to extract the gaseous LNG gas in the buffer tank and pump it to the LNG storage tank, thereby increasing the pressure in the LNG storage tank continuously. The pressure in the LNG storage tank increases until it reaches the preset pressure, and then the booster pump stops working.

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