Self-learning hydrogenation pressure loss estimation method of hydrogenation system

Abstract

This application discloses a self-learning method for estimating hydrogen refueling pressure loss in a hydrogen refueling system. The method includes: approximating the filling link from the break-off valve to the cylinder inlet, assuming a fixed valve value from the break-off valve to the cylinder inlet, with a corresponding pressure drop of , and considering frictional resistance and local resistance during hydrogen refueling, resulting in corresponding pressure drops of and . When performing hydrogen refueling at 70 MPa, the system reads the real-time flow rate from the flowmeter within the system to calculate the equivalent valve value, thereby recording the total pressure loss corresponding to different flow rates. When performing hydrogen refueling at 35 MPa, different flow rates are obtained from the flowmeter, and optimized values ​​are obtained through data mapping to obtain the frictional pressure loss, local pressure loss, and equivalent valve pressure loss under different flow rates. This method solves the technical problem that the lack of an infrared transmitter module at the refueling port of hydrogen-powered vehicles prevents the hydrogen refueling system from obtaining pressure information from the cylinder inlet.

Description

Technical Field

[0001] This application belongs to the field of hydrogenation technology, and in particular relates to a self-learning method for estimating hydrogenation pressure loss in a hydrogenation system. Background Technology

[0002] With the development of society, economy, and science and technology, people are increasingly aware of the importance of environmental protection. Since hydrogen combustion only produces water vapor and no pollutants, and because hydrogen has a high energy density, it can store a large amount of energy. Therefore, using hydrogen as fuel can significantly reduce environmental pollution while allowing hydrogen fuel cell vehicles to have a longer driving range.

[0003] As hydrogen-powered vehicles gradually appear in people's lives, hydrogen production and refueling stations have emerged. Currently, refueling stations are equipped with a large number of hydrogen storage tanks to store hydrogen fuel. When a vehicle needs to refuel, the refueling station can extract hydrogen and fill the vehicle's hydrogen storage space.

[0004] According to section 7.2 Vehicle and Station Dispenser Assumptions of the international standard SAE J2601-2020 "Fueling Protocols for Light Duty Gaseous Hydrogen Surface Vehicles": The vehicle reference pressure drop is 20 MPa from the receptacle to the CHSS and the station dispenser reference pressure drop is 15 MPa from the break-away to the nozzle exit (combined total pressure drop of 35 MPa) at a mass flow rate 1.5 times the average mass flow required to fuel the entire storage capacity in 3 minutes; the maximum peak flow rate specified in this standard is 60 g / s. The vehicle reference pressure drop from the container to the CHSS is 20 MPa, and the station dispenser reference pressure drop from the break-away to the nozzle exit is 15 MPa (total pressure drop of 35 MPa), with a mass flow rate 1.5 times the average mass flow rate required to fuel the entire storage capacity within 3 minutes.

[0005] For high-flow hydrogen dispensers with a maximum peak flow rate greater than 120 g / s, the pressure drop from the hydrogen dispenser's disconnect valve to the gas cylinder inlet directly affects the filling rate and the station's energy consumption.

[0006] Currently, vehicles with a refueling pressure of 70MPa are equipped with an infrared transmitter module at their refueling port. This module transmits information such as the temperature and pressure of the gas cylinder to the hydrogen refueling system according to the international standard protocol SAE J2799. When the hydrogen refueling system is refueling a 70MPa hydrogen-powered vehicle, it can obtain real-time pressure information from the gas cylinder, and simultaneously, it can also obtain real-time temperature and pressure information at its own break-off valve. The pressure drop from the hydrogen refueling system's break-off valve to the gas cylinder inlet can be obtained through the pressure difference between these two points. However, hydrogen-powered vehicles with a refueling pressure of 35MPa do not have an infrared transmitter module at their refueling port, therefore the hydrogen refueling system cannot obtain the pressure information at the gas cylinder inlet.

[0007] How to model and estimate the pressure drop from the breakaway valve to the gas cylinder inlet in a filling system without infrared communication is an urgent problem to be solved. Summary of the Invention

[0008] The purpose of this application is to overcome the problems of the prior art by disclosing a self-learning hydrogen refueling pressure loss estimation method for a hydrogen refueling system. The method of this application solves the technical problem that the lack of an infrared transmitting module at the refueling port of a hydrogen-powered vehicle makes it impossible for the hydrogen refueling system to obtain the pressure information of the gas cylinder inlet.

[0009] The objective of this application is achieved through the following technical solution:

[0010] A self-learning method for estimating hydrogen refueling pressure loss in a hydrogen refueling system, the hydrogen refueling system comprising a hydrogen injector, a 35 MPa hydrogen refueling end and a 70 MPa hydrogen refueling end, wherein the hydrogen injector is connected to the 35 MPa hydrogen refueling end and the 70 MPa hydrogen refueling end respectively via a disconnect valve;

[0011] The self-learning hydrogenation pressure loss estimation method includes:

[0012] Approximating the filling path from the breakaway valve to the cylinder inlet, we assume that the path from the breakaway valve to the cylinder inlet is a... For valves with fixed values, the corresponding pressure drop during hydrogen injection is: Furthermore, during hydrogen refueling, there are frictional and local resistances, resulting in a corresponding pressure drop. and Therefore, the pressure between the break-off valve and the inlet of the vehicle-mounted gas cylinder can be expressed as:

[0013]

[0014] When the hydrogen refueling system is performing hydrogen refueling at the 70MPa end, it acquires real-time pressure information from the gas cylinder and simultaneously acquires real-time pressure information from its own break-off valve. The total pressure loss from the break-off valve to the gas cylinder inlet can be calculated using the pressure difference between these two pressures. By reading the real-time flow rate of the flow meter in the hydrogenation system, the characteristic parameters of the equivalent valve can be determined. The system calculates values ​​and performs self-learning every 100ms to record corresponding feature parameters under different traffic volumes. The corresponding total pressure loss;

[0015] During hydrogenation operations at 35 MPa, different flow rates are obtained using a flow meter, and optimal characteristic parameters are derived through data mapping. The value is used to obtain the friction loss under different flow rates. Local pressure loss and equivalent valve pressure loss .

[0016] According to a preferred embodiment, the self-learning hydrogen refueling pressure loss estimation method further includes: obtaining the pressure value at the on-board bottle valve based on the initial pressure of the break-off valve in the hydrogen refueling system and the total pressure loss of 35 MPa at the hydrogen refueling end.

[0017] According to a preferred embodiment, the pressure drop caused by friction loss is:

[0018]

[0019] l is the pipe length, d is the pipe diameter, and g is the acceleration due to gravity. λ is the flow rate, A is the cross-sectional area of ​​the pipe, and λ is the friction factor.

[0020] According to a preferred embodiment, the pressure drop caused by local resistance is:

[0021]

[0022] in, It is the local drag coefficient.

[0023] According to a preferred embodiment, the pressure drop of compressible hydrogen passing through the valve under non-turbulent conditions is related to the flow rate:

[0024]

[0025] Where N and Sg are constants, It is the real-time pressure loss during the filling process or the equivalent valve pressure loss. It is the flow rate, obtained through a flow meter; and This information can be obtained from the pressure and temperature transmitters at the front end of the breakaway valve. These are the characteristic parameters of the valve.

[0026] According to a preferred embodiment, the temperature value at the bottle neck valve on the vehicle is calculated based on the relationship between pressure, density, and enthalpy.

[0027] The aforementioned main solution and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application. Those skilled in the art, after understanding the solution of this application, will realize that there are many combinations based on the prior art and common general knowledge, all of which are technical solutions to be protected in this application, and will not be exhaustively listed here.

[0028] The beneficial effects of this application are:

[0029] This application solves the technical problem that the lack of an infrared transmitter module at the filling port of hydrogen-powered vehicles prevents the hydrogen refueling system from obtaining pressure information at the cylinder inlet. It enables the effective acquisition of pressure and temperature information at the cylinder inlet of 35MPa hydrogen-powered vehicles, thereby ensuring the safety of the hydrogen refueling process. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the hydrogenation system structure of this application;

[0031] Figure 2 This is a schematic diagram of the equivalent structure of the hydrogen injection pipeline. Detailed Implementation

[0032] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and 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 based on the specific circumstances.

[0037] Furthermore, it should be noted that unless otherwise specified in this application, the specific structures, connections, positions, power sources, etc. involved are all things that a person skilled in the art can know without creative effort based on the prior art.

[0038] Example 1

[0039] refer to Figure 1 and Figure 2 As shown in the figure, a self-learning method for estimating hydrogen refueling pressure loss in a hydrogen refueling system is illustrated. The hydrogen refueling system includes a hydrogen injector, a 35 MPa hydrogen refueling terminal, and a 70 MPa hydrogen refueling terminal. The hydrogen injector is connected to the 35 MPa hydrogen refueling terminal and the 70 MPa hydrogen refueling terminal via a disconnect valve.

[0040] Preferably, the self-learning hydrogenation pressure loss estimation method includes:

[0041] Approximating the filling path from the breakaway valve to the cylinder inlet, we assume that the path from the breakaway valve to the cylinder inlet is a... For valves with a fixed value, the corresponding pressure drop during hydrogen injection is: ,like Figure 2 As shown. Furthermore, during hydrogen refueling, there are frictional and local resistances, resulting in a corresponding pressure drop of... and Therefore, the pressure between the break valve and the inlet of the vehicle-mounted gas cylinder can be expressed as:

[0042] .

[0043] When the hydrogen refueling system is performing hydrogen refueling at the 70MPa end, it acquires real-time pressure information from the gas cylinder and simultaneously acquires real-time pressure information from its own break-off valve. The total pressure loss from the break-off valve to the gas cylinder inlet can be calculated using the pressure difference between these two pressures. By reading the real-time flow rate of the flow meter in the hydrogenation system, the equivalent valve characteristic parameters are obtained. The system calculates values ​​and performs self-learning every 100ms to record corresponding feature parameters under different traffic volumes. The corresponding total pressure loss.

[0044] Specifically, the pressure drop caused by friction along the friction path is:

[0045]

[0046] l is the pipe length, d is the pipe diameter, and g is the acceleration due to gravity. λ is the flow rate, A is the cross-sectional area of ​​the pipe, and λ is the friction factor.

[0047] The pressure drop caused by local resistance is:

[0048]

[0049] in, It is the local drag coefficient.

[0050] The pressure loss of compressible hydrogen passing through a valve under non-turbulent conditions is related to the flow rate:

[0051]

[0052] Where N and Sg are constants, It is the real-time pressure loss during the filling process or the equivalent valve pressure loss. It is the flow rate, obtained through a flow meter; and This information can be obtained from the pressure and temperature transmitters at the front end of the breakaway valve. These are the characteristic parameters of the valve.

[0053] Furthermore, during hydrogenation operations at 35 MPa, different flow rates are obtained using a flow meter, and optimized characteristic parameters are derived through data mapping. The value is used to obtain the friction loss under different flow rates. Local pressure loss and equivalent valve pressure loss During the hydrogenation operation at 35 MPa, the pressure loss along the friction path... Related to real-time flow, local pressure loss Equivalent valve pressure loss related to real-time flow rate With real-time traffic and characteristic parameters Value-related.

[0054] Preferably, the self-learning hydrogen refueling pressure loss estimation method further includes: obtaining the pressure value at the on-board bottle valve based on the initial pressure of the break-off valve in the hydrogen refueling system and the total pressure loss of 35 MPa at the hydrogen refueling end.

[0055] Preferably, during 70MPa vehicle filling, the characteristic parameters are... The value self-learning process includes:

[0056] = - - - ,in It is a compensation pressure for a specific hydrogen charging pipeline, with a value range of -1 to 1 MPa.

[0057] When the feature parameters When the value is set to the initial value (1*e-5), the calculated result is... The pressure monitored in real time during the 70MPa refueling process There are differences. To quickly obtain the optimal feature parameters... The error is approximated quickly by using the derivative direction. That is, the model uses Euclidean distance to represent the error. ,Right now .at this time .

[0058] When traffic When known, , Similar valves Value is irrelevant. , and It is a known value, therefore It is a known value, therefore = + , where α is The variant notation, where α is the flow rate. The function.

[0059] The flow rate value collected from the flow meter at the current moment is If α is a definite value, then the variable is... and ; Known = + ,So ,So ;

[0060] The update step size is set to β=0.1, i.e. , .

[0061] For example: = + When traffic For a given period of time, α is constant, as shown in Table 1.

[0062] Table 1

[0063]

[0064] Therefore, when α = f ( When ) = 1.5, the error is less than the set value of 0.05, therefore this is the optimal value. The value is 0.968, the most recent It is 0.242;

[0065] Similarly, during the 70MPa filling process, it automatically learns different types of... Value and Value. And at the same time The best The best Store it.

[0066] During filling at 35 MPa, based on the measured flow rate Find the best Value and best Value. If Value and If the value is not found in the value table, interpolation is used for calculation. The calculation formula is similar):

[0067]

[0068] Get , , This will give you the 35MPa filling circuit. , , , This allows the pressure of the bottle neck valve to be obtained at 35 MPa. .

[0069] Furthermore, the temperature value at the bottle valve on the vehicle side is calculated based on the relationship between pressure, density, and enthalpy. The heat transfer equation is specifically expressed as:

[0070]

[0071] in, Indicates thermal conductivity, Let t represent temperature and t represent time. These represent the length, thickness, and diameter of the pipe, respectively, and q represents the heat flow rate. This indicates the density of hydrogen gas. Indicates specific heat at constant pressure;

[0072] By making assumptions about the gas cylinder and pipeline, the heat transfer equation is simplified:

[0073]

[0074] The temperature distribution of the pipeline from the breakaway valve to the gas cylinder inlet can be calculated using boundary conditions.

[0075] The temperature and pressure calculations are performed in cyclical steps of 100ms each, until the filling process is complete.

[0076] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A self-learning method for estimating hydrogenation pressure loss in a hydrogenation system, characterized in that, The hydrogen refueling system includes a hydrogen injector, a 35 MPa hydrogen refueling end and a 70 MPa hydrogen refueling end, and the hydrogen injector is connected to the 35 MPa hydrogen refueling end and the 70 MPa hydrogen refueling end respectively via a break-off valve. The self-learning hydrogenation pressure loss estimation method includes: Approximating the filling path from the breakaway valve to the cylinder inlet, we assume that the path from the breakaway valve to the cylinder inlet is a... For valves with fixed values, the corresponding pressure drop during hydrogen injection is: Furthermore, during hydrogen refueling, there are frictional and local resistances, resulting in a corresponding pressure drop. and Therefore, the pressure between the break-off valve and the inlet of the vehicle-mounted gas cylinder can be expressed as: When the hydrogen refueling system is performing hydrogen refueling at the 70MPa end, it acquires real-time pressure information from the gas cylinder and simultaneously acquires real-time pressure information from its own break-off valve. The total pressure loss from the break-off valve to the gas cylinder inlet can be calculated using the pressure difference between these two pressures. By reading the real-time flow rate of the flow meter in the hydrogenation system, the characteristic parameters of the equivalent valve can be determined. The system calculates values ​​and performs self-learning every 100ms to record corresponding feature parameters under different traffic volumes. The corresponding total pressure loss; During hydrogenation operations at 35 MPa, different flow rates are obtained using a flow meter, and optimal characteristic parameters are derived through data mapping. The value is used to obtain the friction loss under different flow rates. Local pressure loss and equivalent valve pressure loss .

2. The self-learning hydrogenation pressure loss estimation method as described in claim 1, characterized in that, The self-learning hydrogen refueling pressure loss estimation method also includes: based on the initial pressure of the break-off valve in the hydrogen refueling system and the total pressure loss of 35MPa at the hydrogen refueling end, the pressure value at the on-board bottle valve is obtained.

3. The self-learning hydrogenation pressure loss estimation method as described in claim 1, characterized in that, The pressure drop caused by friction along the friction path is: l is the pipe length, d is the pipe diameter, and g is the acceleration due to gravity. λ is the flow rate, A is the cross-sectional area of ​​the pipe, and λ is the friction factor.

4. The self-learning hydrogenation pressure loss estimation method as described in claim 3, characterized in that, The pressure drop caused by local resistance is: in, It is the local drag coefficient.

5. The self-learning hydrogenation pressure loss estimation method as described in claim 4, characterized in that, The pressure loss of compressible hydrogen passing through a valve under non-turbulent conditions is related to the flow rate: Where N and Sg are constants, It is the real-time pressure loss during the filling process or the equivalent valve pressure loss. It is the flow rate, obtained through a flow meter; and This information can be obtained from the pressure and temperature transmitters at the front end of the breakaway valve. These are the characteristic parameters of the valve.

6. The self-learning hydrogenation pressure loss estimation method as described in claim 2, characterized in that, The temperature value at the bottle valve on the vehicle end is calculated based on the relationship between pressure, density, and enthalpy.

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