Dual-fuel gas supply system and vehicle

Abstract

The invention relates to a dual-fuel gas supply system and a vehicle, the dual-fuel gas supply system is suitable for the vehicle taking natural gas as a power source, and the system comprises an LNG (Liquefied Natural Gas) supply device and a CNG (Compressed Natural Gas) supply device; the LNG supply device is connected with a natural gas engine of the vehicle and used for supplying gas to the natural gas engine. The CNG supply device is connected with the LNG supply device and the natural gas engine and is used for supplying gas to the vehicle; wherein when the LNG gas supply device supplies gas to the vehicle engine, the CNG gas supply device pressurizes the LNG gas supply device. The two gas supply devices are standby for each other, so that the reliability of the system is improved, the situation that the vehicle cannot run when a single gas supply device breaks down is avoided, and the use cost of the vehicle is reduced; according to the dual-fuel gas supply system, the high-pressure characteristic of the CNG gas supply device is fully utilized, compressed natural gas in the CNG gas supply device is introduced into the LNG gas supply device, the function of pressurizing the LNG gas supply device is achieved, the overall manufacturing cost is reduced, and the practicability of the dual-fuel gas supply system is improved.

Description

Technical Field

[0001] The present application relates to the technical field of natural gas supply systems, and in particular to dual-fuel gas supply systems and vehicles. Background Art

[0002] With the development of natural gas vehicle technology, LNG (liquefied natural gas) and CNG (compressed natural gas) dual-fuel gas supply systems have emerged. This technology is flexible and cost-controlled. It can choose lower-priced fuels according to market changes and add LNG or CNG to reduce vehicle operating costs. Therefore, the market demand for this dual-fuel system is gradually increasing, especially when natural gas prices fluctuate greatly, the dual-fuel gas supply system is particularly important.

[0003] In related technologies, LNG supply systems usually rely on the pressure inside the gas tank to provide fuel for the engine. Common pressurization methods include self-pressurization systems and intelligent pressurization systems. The self-pressurization system slowly increases the pressure through the physical action inside the gas tank, while the intelligent pressurization system quickly increases the pressure through additional equipment to ensure stable gas supply.

[0004] However, the above-mentioned self-pressurizing system has a slow pressurizing speed and is difficult to meet the rapidly changing gas supply demand. Although the intelligent supercharging system has a high supercharging efficiency, the equipment cost is high, which increases the manufacturing and maintenance costs of the vehicle. Summary of the invention

[0005] Based on this, a dual-fuel gas supply system and a vehicle are provided to simultaneously provide LNG and CNG natural gas supplies and realize self-pressurization of the gas supply system.

[0006] In a first aspect, the present application provides a dual-fuel gas supply system suitable for vehicles powered by natural gas, the system comprising:

[0007] An LNG gas supply device, connected to a natural gas engine of a vehicle, for supplying gas to the natural gas engine;

[0008] A CNG gas supply device, connected to the LNG gas supply device and the natural gas engine, for supplying gas to the vehicle;

[0009] When the LNG gas supply device supplies gas to the vehicle engine, the CNG gas supply device pressurizes the LNG gas supply device.

[0010] In one embodiment, the LNG gas supply device comprises:

[0011] LNG tanks, used to store liquefied natural gas;

[0012] LNG gas supply assembly, connected with LNG gas tank and natural gas engine, used to construct LNG gas supply pipeline;

[0013] The LNG filling assembly is connected to the LNG gas tank. The LNG filling assembly includes a filling pipeline and a return gas pipeline, and is used to fill liquefied natural gas into the LNG gas tank.

[0014] In one embodiment, the CNG gas supply device comprises:

[0015] CNG gas tanks, used to store high-pressure natural gas;

[0016] A CNG gas supply assembly, connected to a CNG gas tank and a natural gas engine, for constructing a CNG gas supply pipeline;

[0017] The CNG filling assembly is connected to the CNG gas tank and is used to fill the CNG gas tank with natural gas.

[0018] In one embodiment, the system further comprises:

[0019] The gas supply switching valve 502 is connected to the LNG gas supply device, the CNG gas supply device and the natural gas engine respectively, and is used to control the on-off of the gas supply pipeline between the LNG gas supply device, the CNG gas supply device and the natural gas engine.

[0020] In one embodiment, the LNG gas supply assembly is provided with a liquid outlet stop valve, a vaporizer, a buffer tank and an LNG fine filter in sequence along the output end of the LNG gas tank to the natural gas engine.

[0021] In one embodiment, the LNG gas supply device and the CNG gas supply device are connected via a boosting pipeline, and a boosting pipeline pressure sensor and a boosting pipeline pressure regulating valve are provided on the boosting pipeline, and the boosting pipeline pressure sensor is used to detect the gas phase pressure value in the LNG gas tank;

[0022] When the gas phase pressure value in the LNG tank is low, open the pressure regulating valve of the boosting pipeline to increase the pressure in the LNG tank.

[0023] In one embodiment, the CNG gas supply assembly is provided with a gas supply stop valve, a high-pressure coarse filter valve, a high-pressure pressure reducer and a high-pressure fine filter in sequence along the output end of the CNG gas tank to the natural gas engine.

[0024] In one embodiment, the system further includes a control component, the control component including:

[0025] Liquid level transmitter, used to collect the liquid level in the LNG tank;

[0026] The pipeline switching switch is used to control the position state of the gas supply switching valve 502.

[0027] In one of the embodiments, the LNG gas supply device and the CNG gas supply device further include a plurality of pressure sensors, and the pressure sensors are connected to the control assembly.

[0028] In a second aspect, the present application provides a vehicle, applied to any dual-fuel air supply system provided in the first aspect.

[0029] The above-mentioned dual-fuel gas supply system and vehicle are equipped with both LNG gas supply device and CNG gas supply device on the vehicle to form a dual-fuel gas supply system. The natural gas engine can choose the gas supply device according to the needs, and the user can also selectively refill according to the price of LNG and CNG, which reduces the use cost of the vehicle; the two gas supply devices serve as backup for each other, which improves the reliability of the system and avoids the vehicle being unable to operate due to a single gas supply device failure. On the other hand, the high pressure characteristics of the CNG gas supply device are fully utilized to introduce the compressed natural gas in the CNG gas supply device into the LNG gas supply device to realize the function of pressurizing the LNG gas supply device. There is no need to equip the LNG gas supply device with a self-pressurizing system or an intelligent supercharging system, which reduces the dependence on special supercharging equipment, thereby reducing the equipment cost and assembly complexity in vehicle production, thereby reducing the overall manufacturing cost and improving the practicality of the dual-fuel gas supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] FIG. 1 is a schematic structural diagram of a dual-fuel gas supply system in some embodiments of the present application.

[0032] Description of Figure Numbers:

[0033] 102, LNG tank; 104, liquid level sensor; 106, check valve; 108, liquid stop valve; 110, overflow valve; 112, vaporizer; 114, buffer tank; 116, buffer tank pressure gauge; 118, LNG fine filter; 120, economic valve; 122, auxiliary safety valve; 124, pipeline stop valve; 126, pipeline safety valve; 128, return port; 130, liquid filling port; 132, liquid filling check valve; 134, gas cylinder pressure gauge; 136, main safety valve; 202, CNG tank; 204, gas filling check valve; 206, overflow protection valve; 208, pipeline three-way joint; 210 , CNG cylinder pressure gauge; 212, filling three-way connector; 214, CNG filling port manual stop valve; 216, CNG filling port; 218, CNG vent valve; 220, gas supply stop valve; 222, high-pressure coarse filter; 224, CNG pressure sensor; 226, high-pressure pressure reducer; 228, high-pressure fine filter; 302, liquid level transmitter; 304, vehicle instrument; 306, ECU; 308, pipeline switching switch; 402, boost pipeline pressure sensor; 404, boost pipeline pressure regulating valve; 502, gas supply conversion valve; 504, engine pressure stabilizing valve; 506, natural gas engine. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0035] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0037] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0040] In the first aspect, referring to FIG. 1 , an embodiment of the present application provides a dual-fuel gas supply system suitable for vehicles powered by natural gas, the system comprising an LNG gas supply device and a CNG gas supply device; the LNG gas supply device is connected to the natural gas engine 506 of the vehicle for supplying gas to the natural gas engine; the CNG gas supply device is connected to the LNG gas supply device and the natural gas engine 506 for supplying gas to the vehicle; wherein, when the LNG gas supply device supplies gas to the vehicle engine, the CNG gas supply device pressurizes the LNG gas supply device.

[0041] Among them, LNG (Liquefied Natural Gas) is a form of natural gas that is converted from gas to liquid at extremely low temperatures. CNG (Compressed Natural Gas) is compressed natural gas, which is a form of energy that compresses natural gas at room temperature under high pressure to reduce its volume.

[0042] Specifically, the LNG gas supply device and the CNG gas supply device are on the vehicle and are both connected to the natural gas engine 506. The LNG gas supply device or the CNG gas supply device can be selected to supply gas to the natural gas engine 506 as needed. When the LNG gas supply device supplies gas to the natural gas engine 506, the CNG gas supply device pressurizes the LNG gas supply device.

[0043] In this embodiment, the vehicle is equipped with both an LNG gas supply device and a CNG gas supply device to form a dual-fuel gas supply system. The natural gas engine 506 can select a gas supply device as needed, and the user can also selectively refill according to the price of LNG and CNG, thereby reducing the cost of using the vehicle; the two gas supply devices serve as backup for each other, thereby improving the reliability of the system and avoiding the inability of the vehicle to operate when a single gas supply device fails. On the other hand, the high pressure characteristics of the CNG gas supply device are fully utilized, and the compressed natural gas in the CNG gas supply device is introduced into the LNG gas supply device to realize the function of pressurizing the LNG gas supply device. There is no need to separately equip the LNG gas supply device with a self-pressurizing system or an intelligent supercharging system, thereby reducing the dependence on special supercharging equipment, thereby reducing the equipment cost and assembly complexity in vehicle production, thereby reducing the overall manufacturing cost and improving the practicality of the dual-fuel gas supply system.

[0044] 1 , in some embodiments, the LNG gas supply device includes an LNG gas tank 102, an LNG gas supply assembly and an LNG liquid filling assembly, the LNG gas tank 102 is used to store liquefied natural gas; the LNG gas supply assembly is connected to the LNG gas tank 102 and the natural gas engine 506, and is used to construct an LNG gas supply pipeline; the LNG liquid filling assembly is connected to the LNG gas tank 102, and the LNG liquid filling assembly includes a liquid filling pipeline and a return gas pipeline, and is used to fill liquefied natural gas into the LNG gas tank 102.

[0045] Among them, the LNG gas supply assembly is provided with a liquid outlet stop valve 108, a vaporizer 112, a buffer tank 114 and an LNG fine filter 118 in sequence along the output end of the LNG gas tank 102 to the natural gas engine 506, and the LNG gas supply components are connected by pipelines.

[0046] Specifically, the LNG tank 102 is provided with an output end for outputting LNG, and the output end of the LNG tank 102 is connected to a liquid outlet stop valve 108, which is used to control the liquid outlet state of the LNG tank 102. The liquid outlet stop valve 108 can ensure that when gas supply is not needed, the outflow of LNG is safely cut off to prevent leakage, and can be quickly opened when needed to ensure the smooth supply of LNG. LNG flows through the liquid outlet stop valve 108 to the vaporizer 112. Since LNG is in liquid state in the gas tank, and the natural gas engine 506 uses gaseous natural gas, the vaporizer 112 is used to heat the low-temperature liquid LNG to quickly gasify it into gaseous natural gas, which is convenient for the use of the engine and ensures that the state of the natural gas meets the requirements of the engine. LNG flows from the vaporizer 112 to the buffer tank 114. The buffer tank 114 is used to balance the pressure fluctuations of the LNG gas and play a role in stabilizing the gas supply. After the LNG gas is gasified by the vaporizer 112, the pressure may fluctuate. The buffer tank 114 can absorb these fluctuations to ensure that the gas enters the subsequent system at a stable pressure to avoid affecting the gas supply pipeline and the engine. LNG flows from the buffer tank 114 to the LNG fine filter 118. The LNG fine filter 118 is used to filter impurities or particulate matter in the vaporized LNG gas to ensure the purity of the gas supply, effectively remove possible pollutants, prevent them from entering the engine, ensure the safety and reliability of the engine operation, and extend the service life of the equipment. Furthermore, the LNG gas tank 102 is provided with an output end and an economic valve 120 and a check valve 106 are also arranged in parallel. The economic valve 120 and the check valve 106 are connected in series with the liquid outlet stop valve 108, and the buffer tank 114 is equipped with a buffer tank 114 pressure gauge.

[0047] LNG filling assembly The LNG filling assembly includes a filling pipeline and a return gas pipeline, and the LNG filling assembly is used to fill liquefied natural gas into the LNG tank 102. Specifically, the LNG tank 102 includes a filling end and a return gas end, and the filling end, the return gas end and the output end are arranged from top to bottom in the vertical direction. A filling check valve 132 is provided between the filling end and the filling port 130 of the LNG tank 102 to ensure that LNG can only flow in one direction during the filling process to prevent backflow or leakage. The return gas pipeline is provided with a secondary safety valve 122, a pipeline stop valve 124 and a pipeline safety valve 126 in sequence from the return gas end of the LNG tank 102 to the return gas port 128. The secondary safety valve 122 is used to protect the system under normal working conditions to prevent danger caused by excessive pressure. When the pipeline pressure exceeds the set value, the secondary safety valve 122 will automatically open to release excess gas, thereby reducing the pressure in the pipeline. The pipeline shut-off valve 124 is used to control the flow of gas. It can quickly close the pipeline when necessary to prevent gas leakage or backflow. During maintenance and overhaul, the shut-off valve can effectively cut off the gas flow to ensure safe operation. The pipeline safety valve 126 is used to protect the safety of the return gas pipeline. When an abnormal situation occurs (such as abnormal pressure increase), the pipeline safety valve 126 will open quickly to release the excessive pressure to a safe area. The LNG tank 102 is also connected to the main safety valve 136. When the pressure of the LNG tank 102 exceeds the set safety value, it automatically opens to release excess gas or liquid to prevent the pipeline and equipment from rupture, leakage or other dangerous accidents due to overpressure.

[0048] In this embodiment, the stability and safety of the system are improved as a whole. By optimizing the gas supply path, smooth and continuous gas supply is ensured in the process of LNG being converted from liquid to gas, effectively avoiding the impact of gas pressure fluctuations on engine operation; the pressurization and filtration in the system ensure the purity and pressure stability of the fuel supply, improve the engine's operating efficiency, reduce wear, simplify the manufacturing and maintenance costs of the system, and improve the economy and reliability of the entire vehicle.

[0049] 1 , in some embodiments, the CNG gas supply device includes a CNG gas tank 202, a CNG gas supply assembly and a CNG gas filling assembly; the CNG gas tank 202 is used to store high-pressure natural gas; the CNG gas supply assembly is connected to the CNG gas tank 202 and the natural gas engine 506 to construct a CNG gas supply pipeline; the CNG gas filling assembly is connected to the CNG gas tank 202 to fill the CNG gas tank 202 with natural gas.

[0050] The CNG gas supply assembly is provided with a gas supply stop valve 220 , a high-pressure coarse filter valve, a high-pressure pressure reducer 226 and a high-pressure fine filter 228 in sequence along the output end of the CNG gas tank 202 to the natural gas engine 506 .

[0051] Specifically, the CNG gas tank 202 is provided with an output end for outputting CNG, and the output end of the CNG gas tank 202 is connected to the gas supply stop valve 220, and the gas supply stop valve 220 is used to control the flow of natural gas from the CNG gas tank 202 into the gas supply pipeline. When the gas supply is not needed, the stop valve can completely close the flow of natural gas to ensure safety. CNG flows from the gas supply stop valve 220 to the high-pressure coarse filter valve, and the high-pressure coarse filter valve is used to perform preliminary filtration on the natural gas output from the CNG gas tank 202 to remove larger impurities and particulate matter in the gas. CNG flows from the high-pressure coarse filter valve to the high-pressure reducer 226, and the high-pressure reducer 226 is used to reduce the pressure of the high-pressure natural gas output from the gas tank to a lower pressure suitable for the gas supply system and the engine, ensuring that the gas pressure meets the requirements of the engine; wherein, there are multiple high-pressure reducers 226, and multiple high-pressure reducers 226 are arranged in parallel, and are connected in series with the high-pressure coarse filter valve and the high-pressure fine filter 228, and the high-pressure reducer 226 reduces the pressure through the coolant, and the high-pressure reducer 226 is provided with a coolant inlet and a coolant outlet. CNG flows from the high-pressure reducer 226 to the high-pressure fine filter 228, which is used to filter the natural gas more finely to remove residual tiny particles and impurities in the gas, thereby ensuring that the natural gas entering the engine is pure.

[0052] There are two groups of CNG filling components, which include a CNG filling port 216 manual stop valve 214, a filling three-way joint 212 and a pipeline three-way joint 208, which are arranged in sequence from the CNG filling port 216 to the CNG gas tank 202. The filling three-way joint 212 is connected to the CNG gas tank 202 pressure gauge, and a one-way filling valve and an over-current protection valve 206 are respectively provided at both ends of the CNG gas tank 202.

[0053] In this embodiment, by properly configuring the gas supply stop valve 220, the high-pressure coarse filter valve, the high-pressure pressure reducer 226 and the high-pressure fine filter 228, the gas flow can be effectively controlled to ensure safe operation and prevent leakage; through double filtering measures, the purity of the gas is guaranteed, the wear on the engine is reduced, and the service life of the equipment is extended. In addition, the low CNG pressure reduction ensures a stable and appropriate gas pressure, optimizes the working efficiency of the engine, not only improves the reliability of the gas supply, but also reduces the maintenance cost and safety risks, so that the vehicle can achieve efficient and stable gas supply under complex working conditions.

[0054] 1 , in some embodiments, the system further includes a gas supply switching valve 502 , which is respectively connected to the LNG gas supply device, the CNG gas supply device and the natural gas engine 506 , and is used to control the on / off of the gas supply pipelines between the LNG gas supply device, the CNG gas supply device and the natural gas engine 506 .

[0055] Specifically, the gas supply switching valve 502 includes two gas supply pipelines, which are connected to the LNG gas supply device and the natural gas engine 506, and the CNG gas supply device and the natural gas engine 506, respectively. According to the gas supply of the LNG gas supply device and the CNG gas supply device, the gas supply pipeline is selectively opened or closed. An engine pressure regulating valve 504 is arranged between the gas supply switching valve 502 and the natural gas engine 506. The engine pressure regulating valve 504 can adjust the pressure of the natural gas entering the engine to a suitable level to avoid the influence of excessively high or low pressure on the engine, thereby ensuring the stable operation of the engine.

[0056] In this embodiment, by setting the gas supply conversion valve 502, flexible switching between the LNG gas supply device and the CNG gas supply device is achieved, providing a variety of gas supply options for the natural gas engine 506, significantly improving adaptability and efficiency. The gas supply conversion valve 502 can selectively open or close the gas supply pipeline according to actual needs, and users can flexibly choose LNG or CNG gas supply methods, thereby reducing vehicle use costs and optimizing energy utilization. At the same time, the cooperation between the gas supply conversion valve 502 and the engine pressure regulating valve 504 ensures that the pressure of natural gas entering the engine is always within an appropriate range, avoiding the impact of pressure fluctuations on the engine, ensuring its smooth and efficient operation, reducing safety hazards caused by abnormal pressure, and enhancing the overall safety and reliability of the system.

[0057] Referring to Figure 1, in some embodiments, the LNG gas supply device and the CNG gas supply device are connected through a boosting pipeline, and a boosting pipeline pressure sensor 402 and a boosting pipeline pressure regulating valve 404 are provided on the boosting pipeline. The boosting pipeline pressure sensor 402 is used to detect the gas phase pressure value in the LNG gas tank 102; when the gas phase pressure value in the LNG gas tank 102 is low, the boosting pipeline pressure regulating valve 404 is opened to increase the pressure in the LNG gas tank 102.

[0058] Specifically, the first end of the boost pipeline is arranged between the high-pressure fine filter 228 and the gas supply conversion valve 502, the second end of the boost pipeline is arranged between the pipeline safety valve 126 and the pipeline stop valve 124, and the boost pipeline regulating valve and the boost pipeline sensor are arranged in sequence between the CNG gas supply device and the LNG gas supply device. Exemplarily, when LNG is used to supply the natural gas engine 506, the boost pipeline pressure sensor 402 always monitors the pressure value of the gas phase space in the LNG tank 102, and the CNG pressure sensor 224 always monitors the pressure value in the CNG tank 202. When the pressure value in the LNG tank 102 is less than 0.8 MPa and the pressure value in the CNG tank 202 is greater than 1.2 MPa, the boost pipeline pressure regulating valve 404 opens the valve, and CNG enters the gas phase space in the LNG tank 102 from the outlet of the high-pressure fine filter 228 through the boost pipeline pressure regulating valve 404, the boost pipeline pressure sensor 402, the pipeline stop valve 124 and the corresponding gas supply pipeline to pressurize the LNG tank 102; when the pressure in the LNG tank 102 is greater than 1.1 MPa, the boost pipeline pressure regulating valve 404 closes the valve to stop pressurizing the LNG tank 102.

[0059] In this embodiment, the LNG gas supply device and the CNG gas supply device are connected by a boosting pipeline, which significantly improves the stability and reliability of the gas supply; the boosting pipeline pressure sensor 402 and the boosting pipeline pressure regulating valve 404 can monitor the gas phase pressure in the LNG gas tank 102 in real time and adjust it as needed; when the pressure in the LNG gas tank 102 is low, the boosting pipeline pressure regulating valve 404 will automatically open, allowing CNG to enter the LNG gas tank 102 through the boosting pipeline for boosting, thereby ensuring that the appropriate gas phase pressure is maintained in the LNG gas tank 102, optimizing the gas supply efficiency and system performance.

[0060] 1 , in some embodiments, the system further includes a control component, which includes a liquid level transmitter 302 and a pipeline switch 308. The liquid level transmitter 302 is used to collect the liquid level in the LNG tank 102; the pipeline switch 308 is used to control the position state of the gas supply switching valve 502.

[0061] Specifically, the LNG gas supply device and the CNG gas supply device further include multiple sensors, including a CNG pressure sensor 224, a boost pipeline sensor, and a liquid level sensor 104; the CNG pressure sensor 224 is disposed between the high-pressure reducer 226 and the high-pressure coarse filter 222, and is communicatively connected to the control component; the boost pipeline sensor is communicatively connected to the control component, and the liquid level sensor 104 is disposed in the LNG gas tank 102, and communicates with the liquid level transmitter 302, and is used to measure the LNG liquid level in the LNG gas tank 102. The control component further includes an ECU 306 and a vehicle instrument 304, which are communicatively connected to each sensor.

[0062] Exemplarily, the gas supply switching valve 502 is connected to the pipeline switching switch 308 and the ECU 306 through a wiring harness. The pipeline switching switch 308 is located on the vehicle instrument 304 in the cab. The user operates the pipeline switching switch 308 in the cab to select the LNG gas supply device or the CNG gas supply device to supply gas to the natural gas engine 506. The ECU 306 issues a drive command to control the gas supply switching valve 502 to achieve the switching between the LNG gas supply device and the CNG gas supply device. The pressure range in the CNG gas tank 202 is within the range of 4MPa-20MPa. After passing through the high-pressure reducer 226 and the high-pressure fine filter 228, the pressure is adjusted to 1.1MPa-1.2MPa. Therefore, the CNG gas supply device can always provide pressurized gas to the LNG gas tank 102. When the pressure value in the CNG gas tank 202 is lower than 4MPa, the vehicle instrument 304 prompts the user to add CNG.

[0063] In this embodiment, the intelligence and automation level of gas supply is significantly improved by introducing a control component. The control component includes a liquid level transmitter 302 and a pipeline switching switch 308. The liquid level transmitter 302 monitors the liquid level in the LNG gas tank 102 in real time to ensure that it is within an appropriate range to prevent insufficient gas supply; the pipeline switching switch 308 allows the user to flexibly select LNG or CNG gas supply devices in the cab, thereby improving the convenience of operation; improving the flexibility and response speed of the gas supply system, and reducing the complexity of operation.

[0064] In a second aspect, an embodiment of the present application provides a vehicle, comprising any dual-fuel air supply system provided in the first aspect above.

[0065] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0066] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A dual-fuel gas supply system suitable for vehicles powered by natural gas. It is characterized in that The system comprises: An LNG gas supply device, connected to a natural gas engine of a vehicle, for supplying gas to the natural gas engine; A CNG gas supply device, connected to the LNG gas supply device and the natural gas engine, for supplying gas to the vehicle; When the LNG gas supply device supplies gas to the vehicle engine, the CNG gas supply device pressurizes the LNG gas supply device.

2. The system according to claim 1, It is characterized in that The LNG gas supply device comprises: LNG tanks, used to store liquefied natural gas; An LNG gas supply assembly, connected to the LNG gas tank and the natural gas engine, for constructing an LNG gas supply pipeline; The LNG liquid adding assembly is connected to the LNG gas tank. The LNG liquid adding assembly comprises a liquid adding pipeline and a gas return pipeline, and is used for filling liquefied natural gas into the LNG gas tank.

3. The system according to claim 2, It is characterized in that The CNG gas supply device comprises: CNG gas tanks, used to store high-pressure natural gas; A CNG gas supply assembly, connected to the CNG gas tank and the natural gas engine, for constructing a CNG gas supply pipeline; The CNG filling assembly is connected to the CNG gas tank and is used to fill the CNG gas tank with natural gas.

4. The system according to claim 1, It is characterized in that The system further comprises: The gas supply switching valve is connected to the LNG gas supply device, the CNG gas supply device and the natural gas engine respectively, and is used to control the on-off of the gas supply pipeline between the LNG gas supply device, the CNG gas supply device and the natural gas engine.

5. The system according to claim 2, It is characterized in that The LNG gas supply assembly is provided with a liquid outlet stop valve, a vaporizer, a buffer tank and an LNG fine filter in sequence along the output end of the LNG gas tank to the natural gas engine.

6. The system according to claim 3, It is characterized in that The LNG gas supply device is connected to the CNG gas supply device through a boosting pipeline, and a boosting pipeline pressure sensor and a boosting pipeline pressure regulating valve are provided on the boosting pipeline. The boosting pipeline pressure sensor is used to detect the gas phase pressure value in the LNG gas tank; When the gas phase pressure value in the LNG gas tank is low, the boosting pipeline pressure regulating valve is opened to increase the pressure in the LNG gas tank.

7. The system according to claim 6, It is characterized in that The CNG gas supply assembly is provided with a gas supply stop valve, a high-pressure coarse filter valve, a high-pressure pressure reducer and a high-pressure fine filter in sequence along the output end of the CNG gas tank to the natural gas engine.

8. The system according to claim 4, It is characterized in that The system also includes a control component, which includes: Liquid level transmitter, used to collect the liquid level in the LNG tank; The pipeline switching switch is used to control the position state of the gas supply switching valve.

9. The system according to claim 8, It is characterized in that The LNG gas supply device and the CNG gas supply device further include a plurality of pressure sensors, and the pressure sensors are connected to the control assembly.

10. A vehicle, It is characterized in that A dual-fuel gas supply system comprising any one of claims 1-9.

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