Gas supply system of LNG vehicle and LNG vehicle

Abstract

The application relates to the technical field of LNG vehicles, and particularly provides a gas supply system of an LNG vehicle and the LNG vehicle, which aims to solve the problem that cold energy generated by LNG gasification is directly released into the environment, resulting in waste of the cold energy. For the purpose, the gas supply system of the LNG vehicle comprises an LNG storage tank for storing liquefied natural gas; a gas mixing device, whose gas outlet is communicated with an engine; a gasifier, one end of which is communicated with the LNG storage tank and the other end of which is communicated with an air inlet of the gas mixing device; and an evaporator, one end of which is communicated with the LNG storage tank and the other end of which is communicated with the air inlet of the gas mixing device, wherein the evaporator can supply cold energy for a refrigeration box. The gas supply system of the LNG vehicle provided by the application can complete the conventional gas supply for the engine, recover part of the cold energy generated by LNG gasification, and achieve the purpose of energy saving and consumption reduction.

Description

Technical Field

[0001] This application relates to the field of LNG vehicle technology, specifically providing an LNG vehicle gas supply system and an LNG vehicle. Background Technology

[0002] Currently, liquefied natural gas (LNG) is widely used as a clean energy source in heavy-duty trucks, refrigerated trucks, and RVs. LNG has a boiling point of approximately -162°C at atmospheric pressure. When it flows out of a storage tank, it needs to absorb a large amount of heat to change from a liquid to a gaseous state for combustion in an engine.

[0003] In related technologies, LNG vehicles use a vaporizer to vaporize LNG and heat it to a state suitable for engine operation, then directly release the cooling energy generated by LNG vaporization into the environment. However, directly releasing the cooling energy generated by LNG vaporization into the environment leads to a waste of cooling capacity.

[0004] Therefore, a new technical solution is needed in this field to solve the above problems. Utility Model Content

[0005] This application aims to solve the aforementioned technical problem, namely, the waste of cooling energy caused by directly releasing the cooling energy generated by LNG gasification into the environment.

[0006] In a first aspect, this application provides a gas supply system for an LNG vehicle, the LNG vehicle including a refrigerated container and an engine, the gas supply system including: an LNG storage tank for storing liquefied natural gas; a gas mixing device whose outlet is connected to the engine; a vaporizer whose one end is connected to the LNG storage tank and the other end is connected to the inlet of the gas mixing device; and an evaporator whose one end is connected to the LNG storage tank and the other end is connected to the inlet of the gas mixing device, the evaporator being capable of providing cooling for the refrigerated container.

[0007] In some embodiments, the gas supply system further includes a flow distribution unit connected between the LNG storage tank, the vaporizer, and the evaporator. The flow distribution unit is used to guide a first flow of liquefied natural gas to the vaporizer and a second flow of liquefied natural gas to the evaporator, wherein the first flow is greater than the second flow.

[0008] In some embodiments, the ratio between the first flow rate and the second flow rate is greater than or equal to 9:1.

[0009] In some embodiments, the flow distribution unit is a three-way valve, the first port of the three-way valve is connected to the LNG storage tank, the second port of the three-way valve is connected to the vaporizer, and the third port of the three-way valve is connected to the evaporator.

[0010] In some embodiments, the gas supply system further includes a pressure regulator disposed between the LNG storage tank and the three-way valve, the pressure regulator being used to regulate the pressure of the liquefied natural gas flowing to the three-way valve.

[0011] In some embodiments, the gas supply system further includes a control device and a temperature sensor. The temperature sensor is used to detect the current temperature inside the refrigerator. The control device is communicatively connected to the temperature sensor and the three-way valve to adjust the opening of the three-way valve according to the current temperature and the set temperature of the refrigerator.

[0012] In some embodiments, a check valve is provided between the evaporator and the gas mixing device, the check valve being configured to allow natural gas to flow from the evaporator to the gas mixing device.

[0013] In some embodiments, a gas-liquid separator is provided between the evaporator and the gas mixing device, the gas-liquid separator being used to separate gaseous natural gas and liquefied natural gas, allowing gaseous natural gas to enter the engine.

[0014] Secondly, this application provides an LNG vehicle, which includes the refrigerated container, the engine, and the aforementioned LNG vehicle gas supply system.

[0015] In some embodiments, the evaporator is disposed inside the refrigerator, and the refrigerator is also provided with a fan.

[0016] With the above-mentioned technical solution, the LNG vehicle gas supply system of this application mainly consists of an LNG storage tank, a gas mixing device, a vaporizer, and an evaporator. The LNG storage tank is used to store liquefied natural gas. The vaporizer and evaporator form a parallel branch, with one end of each connected to the LNG storage tank and the other end converging into the inlet of the gas mixing device. Thus, when the gas supply system is running, the LNG is split. One part of the LNG flows into the evaporator, where it vaporizes and absorbs heat, lowering the evaporator's temperature and thus cooling the refrigerator. The other part of the LNG enters the vaporizer, where it completes its vaporization. Subsequently, the two LNG streams are thoroughly mixed in the gas mixing device to form a stable gas mixture at a stable temperature and pressure for the engine. By adding an evaporator connected in parallel with the vaporizer, this application achieves the goal of recovering some of the cooling energy generated by LNG vaporization while providing regular gas supply to the engine, thus achieving energy saving and consumption reduction. Attached Figure Description

[0017] The preferred embodiments of this application are described below with reference to the accompanying drawings, in which:

[0018] Figure 1This is a schematic diagram of the gas supply system for the LNG vehicle in this application; Figure 2 This is another schematic diagram of the gas supply system for the LNG vehicle in this application.

[0019] List of reference numerals in the attached diagram: 1. Engine; 2. LNG storage tank; 3. Gas mixing device; 4. Vaporizer; 5. Evaporator; 6. Check valve; 7. Gas-liquid separator; 8. Three-way valve. Detailed Implementation

[0020] Preferred embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application. It should be noted that in the description of this application, terms such as "upper," "lower," "inner," "bottom," and "end," indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, it should not be construed as a limitation of this application.

[0021] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "set up," "connect," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] Currently, liquefied natural gas (LNG) is widely used as a clean energy source in heavy-duty trucks, refrigerated trucks, and RVs. LNG has a boiling point of approximately -162°C at atmospheric pressure. When it flows out of a storage tank, it needs to absorb a large amount of heat to change from a liquid to a gaseous state for combustion in an engine.

[0023] In related technologies, LNG vehicles use a vaporizer to directly release the cooling energy generated by LNG vaporization into the environment, allowing the LNG to vaporize and warm up to a state suitable for engine operation. However, directly releasing the cooling energy generated by LNG vaporization into the environment leads to a waste of cooling capacity.

[0024] This application provides an LNG vehicle gas supply system and an LNG vehicle, which can recover part of the cooling energy generated by LNG vaporization, thereby achieving the purpose of energy saving and consumption reduction.

[0025] In one aspect, this application provides an LNG vehicle gas supply system.

[0026] LNG vehicles are new energy vehicles that use liquefied natural gas as fuel. A dedicated gas supply system vaporizes the LNG and supplies it to the engine for combustion, propelling the vehicle. LNG vehicles offer advantages such as high energy density and long driving range, and are widely used in heavy-duty trucks, buses, refrigerated trucks, sanitation vehicles, and recreational vehicles.

[0027] LNG vehicles include a refrigerated container and an engine 1, combined with Figure 1 As shown, the gas supply system for the LNG vehicle provided in this application includes an LNG storage tank 2, a gas mixing device 3, a vaporizer 4, and an evaporator 5.

[0028] LNG storage tank 2 is used to store liquefied natural gas.

[0029] The outlet of the gas mixing device 3 is connected to the engine 1. After the gaseous LNG is mixed evenly in the gas mixing device 3, it is supplied to the engine 1 for combustion.

[0030] One end of the vaporizer 4 is connected to the LNG storage tank 2, and the other end of the vaporizer 4 is connected to the air inlet of the gas mixing device 3.

[0031] One end of the evaporator 5 is connected to the LNG storage tank 2, and the other end of the evaporator 5 is connected to the air inlet of the gas mixing device 3. The evaporator 5 can provide cooling for the refrigerated container. That is, the vaporizer 4 and the evaporator 5 are connected in parallel.

[0032] With the above technical solution adopted, the LNG vehicle gas supply system of this application mainly consists of an LNG storage tank 2, a gas mixing device 3, a vaporizer 4, and an evaporator 5. The LNG storage tank 2 is used to store liquefied natural gas. The vaporizer 4 and the evaporator 5 form a parallel branch, with one end of each connected to the LNG storage tank 2, and the other end converging into the inlet of the gas mixing device 3. Thus, when the gas supply system is running, the LNG is diverted. One part of the LNG flows into the evaporator 5, where it vaporizes and absorbs heat, lowering the temperature of the evaporator 5 and thus cooling the refrigerated container. The other part of the LNG enters the vaporizer 4, where it undergoes vaporization. Subsequently, the two LNG streams are thoroughly mixed in the gas mixing device 3 to form a stable gas mixture at a stable temperature and pressure, which is then supplied to the engine 1. By adding an evaporator 5 connected in parallel with the vaporizer 4, this application achieves the goal of energy saving and consumption reduction while simultaneously supplying gas to the engine 1.

[0033] In an exemplary embodiment, the gas mixing device 3 can be a standalone structure or an integrated structure into components such as an engine. Those skilled in the art can flexibly configure the gas mixing device 3 as needed, as long as the gas mixing device 3 can achieve the function of gas mixing. After mixing by the gas mixing device 3, the temperature and density of the gas will become more uniform, which is beneficial to improving the stability of the gas supply to the engine 1.

[0034] In some embodiments, the gas supply system further includes a flow distribution unit connected between the LNG storage tank 2, the vaporizer 4, and the evaporator 5. The flow distribution unit is used to guide a first flow of liquefied natural gas to the vaporizer 4 and a second flow of liquefied natural gas to the evaporator 5, wherein the first flow is greater than the second flow.

[0035] The flow rate of LNG allocated to the vaporizer 4 and evaporator 5 can be adjusted by setting up a flow distribution unit. The LNG flowing through the vaporizer 4 is the first flow rate, and the LNG flowing through the evaporator 5 is the second flow rate, with the first flow rate being greater than the second. A small portion of the LNG enters the evaporator, where it absorbs heat from the air in the refrigerated compartment, achieving vaporization while simultaneously cooling the compartment. The vaporized LNG flows out of the evaporator and into the gas mixing device 3. At the same time, most of the LNG enters the vehicle's original vaporizer 4, where it is fully heated by the engine's high-temperature coolant, completely vaporizing into gaseous natural gas at room temperature or slightly below ambient temperature, meeting the engine's operating requirements and ensuring normal combustion and stable operation. This flow distribution design satisfies the engine 1's requirements for gas supply flow and temperature while also recovering some of the cooling energy from LNG vaporization through the evaporator 5, thus improving energy efficiency.

[0036] In the exemplary embodiment, it is not necessary for the first flow rate to be greater than the second flow rate; those skilled in the art can flexibly set it as needed. For example, those skilled in the art can make the first flow rate equal to the second flow rate, or make the first flow rate less than the second flow rate, as needed.

[0037] In some embodiments, the ratio between the first flow rate and the second flow rate is greater than or equal to 9:1. For example, the ratio between the first flow rate and the second flow rate is 9:1, 9.2:0.8, or 9.5:0.5, etc. This configuration satisfies the engine 1's requirements for gas supply flow rate and temperature, while also recovering some of the cold energy from LNG vaporization through the evaporator 5, which is beneficial for improving energy utilization efficiency.

[0038] In the exemplary embodiments, the specific ratio between the first flow rate and the second flow rate is not fixed in this application, and those skilled in the art can adjust it as needed. For example, those skilled in the art can set the ratio between the first flow rate and the second flow rate to 8:2, 7:3, 5:5, 3:7, or 9.2:0.8, etc., as required.

[0039] Optionally, the vaporizer 4 is a water-jacketed vaporizer.

[0040] In some embodiments, combined with Figure 2 As shown, the flow distribution unit is a three-way valve 8. The first port of the three-way valve 8 is connected to the LNG storage tank 2, the second port is connected to the vaporizer 4, and the third port is connected to the evaporator 5. The three-way valve 8 guides a first flow of liquefied natural gas to the vaporizer 4 through the second port and a second flow of liquefied natural gas to the evaporator 5 through the third port. The flow rate of LNG distributed to the vaporizer 4 and the evaporator 5 can be adjusted by regulating the opening degree of each port of the three-way valve 8.

[0041] In the exemplary embodiment, the three-way valve 8 is not mandatory, and those skilled in the art can select it as needed. Without the three-way valve 8, the flow distribution unit may include a first regulating valve and a second regulating valve. The first regulating valve is located between the LNG storage tank 2 and the vaporizer 4, and the second regulating valve is located between the LNG storage tank 2 and the evaporator 5. By adjusting the opening of the first and second regulating valves, the flow rate of LNG flowing through the vaporizer 4 and the evaporator 5 is adjusted.

[0042] In some embodiments, the gas supply system further includes a pressure regulator disposed between the LNG storage tank 2 and the three-way valve 8, the pressure regulator being used to regulate the pressure of the liquefied natural gas flowing to the three-way valve 8. The pressure regulator can keep the pressure at the outlet of the LNG storage tank 2 stable.

[0043] Optionally, the pressure regulator is a pressure regulating valve, which automatically adjusts the outlet pressure through a diaphragm, spring, lever, and valve core structure. The specific adjustment principle is as follows: When downstream gas consumption decreases or upstream pressure increases, causing an upward trend in outlet pressure, the outlet pressure is transmitted to the lower part of the diaphragm, causing the upward force acting on the diaphragm to exceed the downward preload of the spring, pushing the diaphragm upward. Through lever transmission, the valve core moves in the closing direction, correspondingly reducing the LNG flow through the valve, thereby suppressing the continuous rise in downstream pressure and causing it to fall back to the set value. Conversely, when downstream gas consumption increases or upstream pressure decreases, causing a downward trend in outlet pressure, the pressure on the lower part of the diaphragm is less than the spring preload, and the diaphragm moves downward under the action of the spring. Through lever transmission, the valve core moves in the opening direction, correspondingly increasing the LNG flow through the valve, thereby preventing the continuous drop in downstream pressure and causing it to rise back to the set value.

[0044] In some embodiments, the gas supply system further includes a control device and a temperature sensor. The temperature sensor is used to detect the current temperature inside the refrigerator. The control device is communicatively connected to the temperature sensor and the three-way valve 8 to adjust the opening degree of the three-way valve 8 according to the current temperature and the set temperature of the refrigerator. By installing a temperature sensor inside the refrigerator, the temperature inside the refrigerator can be detected in real time and transmitted to the control device, which can then adjust the opening degree of the three-way valve 8 according to the current temperature and the set temperature.

[0045] Optionally, the gas supply system may prioritize the engine's needs.

[0046] In some embodiments, combined with Figure 2 As shown, a check valve 6 is installed between the evaporator 5 and the gas mixing device 3. The check valve 6 is configured to allow natural gas to flow from the evaporator 5 to the gas mixing device 3. This configuration prevents gaseous LNG from flowing back from the gas mixing device 3 to the evaporator 5, ensuring unidirectional flow of gaseous LNG and guaranteeing safety. Specifically, the internal pressure of the gas mixing device 3 needs to be adapted to the engine operating conditions. LNG absorbs heat and vaporizes in the evaporator 5, and a low-pressure environment is more conducive to efficient refrigeration. Therefore, the evaporator 5 needs to maintain a relatively low-pressure heat exchange environment. If the check valve 6 is not installed, a sudden acceleration of the engine or a sudden increase in the gas supply flow will cause a momentary high pressure in the gas mixing device 3. The high-pressure natural gas inside may flow back into the evaporator 5, causing an abnormal increase in pressure within the evaporator 5. This would disrupt the low-pressure heat exchange conditions of the evaporator 5, significantly reducing the refrigeration efficiency of the refrigerator; and it may also exceed the design pressure range of the evaporator 5, causing problems such as seal leakage and heat exchange tube deformation. By setting a check valve 6, the reverse flow path from the gas mixing device 3 to the evaporator 5 can be blocked, ensuring that the evaporator 5 is always in a stable low-pressure working environment, and ensuring the continuous and reliable refrigeration function of the refrigerator.

[0047] In the exemplary embodiment, the check valve 6 is not required, and those skilled in the art may choose to include it as needed.

[0048] In some embodiments, combined with Figure 2 As shown, a gas-liquid separator 7 is installed between the evaporator 5 and the gas mixing device 3. The gas-liquid separator 7 is used to separate gaseous natural gas and liquefied natural gas, allowing gaseous natural gas to enter the engine 1. By installing the gas-liquid separator 7 between the evaporator 5 and the gas mixing device 3, it can be ensured that the LNG entering the engine 1 is gaseous LNG, preventing liquefied LNG from entering the engine 1. This avoids problems such as engine liquid slugging, incomplete combustion, engine instability, and excessive pollutant emissions caused by liquefied LNG entering the engine.

[0049] In the exemplary embodiment, the gas-liquid separator 7 is not required, and those skilled in the art can choose it as needed.

[0050] In the exemplary embodiment, the location of the gas-liquid separator 7 is not fixed, and those skilled in the art can select it as needed. For example, the gas-liquid separator 7 can be located between the check valve 6 and the evaporator 5, or the gas-liquid separator 7 can be located between the check valve 6 and the gas mixing device 3.

[0051] Secondly, this application provides an LNG vehicle.

[0052] The LNG vehicle provided in this application includes a refrigerated container, engine 1, and the gas supply system for the aforementioned LNG vehicle.

[0053] With the above technical solution adopted, the LNG vehicle gas supply system of this application mainly consists of an LNG storage tank 2, a gas mixing device 3, a vaporizer 4, and an evaporator 5. The LNG storage tank 2 is used to store liquefied natural gas. The vaporizer 4 and the evaporator 5 form a parallel branch, with one end of each connected to the LNG storage tank 2, and the other end converging into the inlet of the gas mixing device 3. Thus, when the gas supply system is running, the LNG is diverted. One part of the LNG flows into the evaporator 5, where it vaporizes and absorbs heat, lowering the temperature of the evaporator 5 and thus cooling the refrigerated container. The other part of the LNG enters the vaporizer 4, where it undergoes vaporization. Subsequently, the two LNG streams are thoroughly mixed in the gas mixing device 3 to form a stable gas mixture at a stable temperature and pressure, which is then supplied to the engine 1. By adding an evaporator 5 connected in parallel with the vaporizer 4, this application achieves the goal of energy saving and consumption reduction while simultaneously supplying gas to the engine 1.

[0054] Alternatively, the refrigerator can be an insulated container. This reduces heat exchange between the refrigerator and the outside environment, minimizing cold loss.

[0055] In some embodiments, the evaporator 5 is disposed inside the refrigerator, and a fan is also disposed inside the refrigerator. By disposing of a fan inside the refrigerator, the airflow inside the refrigerator can be promoted, the heat exchange efficiency between the air inside the refrigerator and the evaporator 5 can be enhanced, and the temperature inside the refrigerator can be made more uniform.

[0056] Optionally, the engine includes a gas injection system, and a gas mixing device 3 is connected to the gas injection system. The gas injection system sends the mixed gaseous LNG into the combustion chamber of the engine for combustion and power generation.

[0057] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0058] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A gas supply system for an LNG vehicle, the LNG vehicle comprising a refrigerated container and an engine (1), characterized in that, The gas supply system includes: LNG storage tank (2), used for storing liquefied natural gas; A gas mixing device (3) has its outlet connected to the engine (1); The vaporizer (4) has one end connected to the LNG storage tank (2) and the other end connected to the air inlet of the gas mixing device (3); The evaporator (5) is connected at one end to the LNG storage tank (2) and at the other end to the air inlet of the gas mixing device (3). The evaporator (5) can provide cooling for the refrigerated container.

2. The gas supply system according to claim 1, characterized in that, The gas supply system also includes a flow distribution unit connected between the LNG storage tank (2), the vaporizer (4) and the evaporator (5). The flow distribution unit is used to guide a first flow of liquefied natural gas to the vaporizer (4) and a second flow of liquefied natural gas to the evaporator (5). The first flow is greater than the second flow.

3. The gas supply system according to claim 2, characterized in that, The ratio between the first flow rate and the second flow rate is greater than or equal to 9:

1.

4. The gas supply system according to claim 2, characterized in that, The flow distribution unit is a three-way valve (8). The first port of the three-way valve (8) is connected to the LNG storage tank (2), the second port of the three-way valve (8) is connected to the vaporizer (4), and the third port of the three-way valve (8) is connected to the evaporator (5).

5. The gas supply system according to claim 4, characterized in that, The gas supply system also includes a pressure regulator disposed between the LNG storage tank (2) and the three-way valve (8), the pressure regulator being used to regulate the pressure of the liquefied natural gas flowing to the three-way valve (8).

6. The gas supply system according to claim 4, characterized in that, The gas supply system also includes a control device and a temperature sensor. The temperature sensor is used to detect the current temperature inside the refrigerator. The control device is communicatively connected to the temperature sensor and the three-way valve (8) to adjust the opening of the three-way valve (8) according to the current temperature and the set temperature of the refrigerator.

7. The gas supply system according to any one of claims 1 to 6, characterized in that, A check valve (6) is provided between the evaporator (5) and the gas mixing device (3), and the check valve (6) is configured to allow natural gas to flow from the evaporator (5) to the gas mixing device (3).

8. The gas supply system according to any one of claims 1 to 6, characterized in that, A gas-liquid separator (7) is provided between the evaporator (5) and the gas mixing device (3). The gas-liquid separator (7) is used to separate gaseous natural gas and liquid natural gas, allowing gaseous natural gas to enter the gas mixing device (3).

9. An LNG vehicle, characterized in that, The LNG vehicle includes the refrigerated container, the engine (1), and the LNG vehicle gas supply system as claimed in any one of claims 1 to 8.

10. The LNG vehicle according to claim 9, characterized in that, The evaporator (5) is installed inside the refrigerator, and a fan is also installed inside the refrigerator.

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