Selection method and device of turbocharger for turbocharged hydrogen internal combustion engine and turbocharged hydrogen internal combustion engine

Abstract

The present application provides a method for selecting a supercharger for a supercharged hydrogen internal combustion engine, which calculates the air flow rate and the hydrogen flow rate according to the matching point of the hydrogen internal combustion engine and the excess air coefficient; calculates the mass fraction of the exhaust components of the hydrogen internal combustion engine according to the chemical formula of the hydrogen and air reaction in combination with the excess air coefficient; sets the exhaust temperature at the turbine inlet of the supercharger, and determines the constant-pressure specific heat capacity of the mixed gas constituting the exhaust at the set exhaust temperature in combination with the mass fraction of the exhaust components; calculates the theoretical value of the exhaust temperature at the turbine inlet according to the target effective thermal efficiency and heat transfer ratio predicted by the matching point of the hydrogen internal combustion engine in combination with the constant-pressure specific heat capacity of the mixed gas, and when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within the threshold, the set exhaust temperature at the turbine inlet is the determined exhaust temperature; based on the determined exhaust temperature, the turbine expansion ratio is determined in combination with the parameters of the compressor of the supercharger. The supercharger selected in the present application has a better match with the hydrogen internal combustion engine.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen internal combustion engines, and in particular to a method for selecting a supercharger of a supercharged hydrogen internal combustion engine, a selection device, a supercharged hydrogen internal combustion engine and a computing device. Background Art

[0002] As the global energy crisis intensifies, countries are beginning to accelerate their research on new energy sources, seeking renewable energy carriers that can replace traditional fuels; at the same time, countries are facing severe problems such as severe domestic air pollution and escalating greenhouse effects, and are beginning to demand a reduction in CO2 emissions. As a clean energy carrier, hydrogen does not contain carbon during combustion, so it does not produce CO2 emissions, and the only harmful emissions are nitrogen oxides (NOx). When hydrogen burns, it has the characteristics of fast combustion speed, low ignition energy, and few pollutants produced by combustion. At the same time, the current internal combustion engines have technical advantages such as good industrial foundation, low cost, high reliability, and long service life, which has attracted widespread attention to the development of hydrogen internal combustion engines.

[0003] For hydrogen internal combustion engines with external injection, the hydrogen nozzle is usually located in the intake manifold of the cylinder of the hydrogen internal combustion engine. Hydrogen, as a gas, occupies the volume of the intake duct, and the air-fuel ratio of hydrogen is relatively large. In order to improve the thermal efficiency of the hydrogen internal combustion engine and reduce NOx emissions, a lean burn strategy is generally adopted. These factors make the output power of hydrogen internal combustion engines lower than that of other traditional gas engines of the same displacement. Therefore, supercharging and direct injection are means to improve the power performance of hydrogen internal combustion engines. However, since the modification cost of direct injection hydrogen internal combustion engines is higher than that of intake duct injection hydrogen internal combustion engines, and the parts requirements are more complex, it is more necessary to study the supercharging matching of hydrogen internal combustion engines.

[0004] For the selection of turbochargers for common gasoline and natural gas engines, it is only necessary to roughly calculate the required air flow and boost pressure according to the power and displacement of the target matching point (here refers to the engine), determine the relevant parameters of the turbocharger's compressor and turbine, and select a suitable turbocharger. For turbocharged hydrogen internal combustion engines, the exhaust temperature is lower due to the use of a lean burn strategy. In addition, since hydrogen itself does not contain C elements and its combustion products are all H2O, the exhaust components are significantly different from other fuel gases and traditional gasoline engines, resulting in different gas enthalpy values ​​entering the turbocharger's turbine. Therefore, the turbocharger for the turbocharged hydrogen internal combustion engine needs to be reselected.

[0005] Therefore, a selection scheme for a turbocharger suitable for a supercharged hydrogen internal combustion engine is yet to be provided. Summary of the invention

[0006] To achieve the above objectives, the present application provides a method for selecting a supercharger for a supercharged hydrogen internal combustion engine, a selection device, a supercharged hydrogen internal combustion engine and a computing device, which are suitable for selecting a turbocharger for a hydrogen internal combustion engine.

[0007] The first aspect of the present application provides a method for selecting a supercharger for a supercharged hydrogen internal combustion engine, comprising:

[0008] Calculate the air flow rate and hydrogen flow rate according to the matching point of the hydrogen internal combustion engine and the given excess air coefficient;

[0009] Calculate the mass fraction of exhaust components of the hydrogen internal combustion engine according to the chemical equation of the reaction between hydrogen and air and in combination with the excess air coefficient;

[0010] Setting the exhaust gas temperature at the turbine inlet of the supercharger, and determining the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature in combination with the mass fraction of the exhaust gas components;

[0011] The theoretical value of the exhaust temperature at the turbine inlet is calculated according to the target effective thermal efficiency and heat transfer ratio predicted at the matching point of the hydrogen internal combustion engine, in combination with the constant-pressure specific heat capacity of the mixed gas; when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold, the set exhaust temperature at the turbine inlet is the determined exhaust temperature at the turbine inlet;

[0012] Based on the determined exhaust gas temperature at the turbine inlet and in combination with the parameters of the compressor of the supercharger, the turbine expansion ratio of the supercharger is determined.

[0013] From the above, in the process of selecting a supercharger for a supercharged hydrogen internal combustion engine, the present application considers the difference in exhaust gas components after hydrogen combustion, and at the same time corrects the exhaust temperature at the turbine inlet to ensure that the expansion ratio calculation result is as accurate as possible. Among them, the present application calculates the exhaust temperature at the turbine inlet of the supercharger, combines the target boost pressure set by the matching point, the specific heat capacity of the exhaust gas at the turbine inlet and the adiabatic index, and obtains the expansion ratio of the turbine, so as to achieve a good selection of the turbine for the supercharger of the supercharger of the supercharger of the supercharged hydrogen internal combustion engine. The turbine of the supercharger thus selected can be well matched with its compressor, and the selected supercharger is well matched with the hydrogen internal combustion engine.

[0014] As a possible implementation method of the first aspect, when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is not within a threshold value, the set exhaust temperature at the turbine inlet is adjusted, the constant-pressure specific heat capacity of the exhaust mixed gas is re-determined, and the theoretical value of the exhaust temperature at the turbine inlet is recalculated.

[0015] From the above, by correcting the iterative calculation of the exhaust gas temperature at the turbine inlet, a more accurate result is obtained, thereby achieving a good selection of the turbine for the supercharger of the supercharged hydrogen internal combustion engine.

[0016] As a possible implementation of the first aspect, the air flow rate and the hydrogen flow rate are calculated according to the following formula:

[0017]

[0018]

[0019] Among them, M C is the air flow rate; M H is the hydrogen flow rate; P e is the target power of the hydrogen internal combustion engine at the matching point; H u is the calorific value of hydrogen; η is the target effective thermal efficiency in the matching point of the hydrogen internal combustion engine; L0 is the theoretical amount of air required for complete combustion of one kilogram of hydrogen; λ is the excess air coefficient.

[0020] As a possible implementation of the first aspect, the chemical equation for the reaction of hydrogen and air is:

[0021] 2H2+λO2+3.71λN2=2H2O+(λ-1)O2+3.71·λN2

[0022] The mass fraction of exhaust components of a hydrogen internal combustion engine is calculated according to the following formula:

[0023]

[0024]

[0025]

[0026] Among them, H2 is hydrogen; O2 is oxygen; N2 is nitrogen; H2O is water, which here means water vapor; represents the mass fraction of water vapor in the exhaust gas of a hydrogen internal combustion engine, Represents the oxygen mass fraction in the exhaust gas of a hydrogen internal combustion engine; Represents the mass fraction of nitrogen in the exhaust gas of a hydrogen internal combustion engine.

[0027] As a possible implementation of the first aspect, the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature is determined by calculating according to the following formula:

[0028]

[0029] Where: C p mix is the constant pressure specific heat capacity of the mixed gas; is the specific heat capacity of water vapor at constant pressure; is the constant pressure specific heat capacity of oxygen; is the constant pressure specific heat capacity of nitrogen.

[0030] As a possible implementation of the first aspect, the theoretical value of the exhaust temperature at the turbine inlet is calculated according to the following formula:

[0031]

[0032] Where: T t2 is the theoretical value of exhaust temperature at turbine inlet; η cooling is the heat transfer ratio, C pintake is the constant pressure specific heat capacity of the intake air; T C2 It is the temperature of the intake air after passing through the intercooler.

[0033] As a possible implementation of the first aspect, the turbine expansion ratio of the supercharger is determined by calculating according to the following formula:

[0034]

[0035] Among them, η TL =η sL ·η mL ·η sT ·η mT

[0036] in: is the turbine expansion ratio of the supercharger; p4t is the pressure at the turbine outlet; p 3t is the pressure at the turbine inlet; p 2t is the pressure at the compressor outlet; p 1t is the pressure at the compressor inlet; κL is the adiabatic index of the gas in the compressor; is the gas flow rate through the compressor; is the gas flow rate through the turbine; T c1 is the intake air temperature at the compressor inlet; T t1 is the determined exhaust temperature at the turbine inlet; κT is the adiabatic index of the gas in the turbine;

[0037] η TL Represents the overall turbocharger efficiency; η sL is the isentropic efficiency of the compressor; η mL is the mechanical efficiency of the compressor; η sT is the isentropic efficiency of the turbine; η mT is the mechanical efficiency of the turbine.

[0038] In a second aspect of the present application, there is provided a device for selecting a supercharger for a supercharged hydrogen internal combustion engine, comprising: a first calculation unit, for calculating an air flow rate and a hydrogen flow rate according to a matching point of the hydrogen internal combustion engine and a given excess air coefficient; a second calculation unit, for calculating the mass fraction of exhaust components of the hydrogen internal combustion engine according to a chemical equation for the reaction of hydrogen and air in combination with the excess air coefficient; a third calculation unit, for setting the exhaust temperature at the turbine inlet of the supercharger, and determining the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature in combination with the mass fraction of the exhaust components; a fourth calculation unit, for calculating the theoretical value of the exhaust temperature at the turbine inlet according to the target effective thermal efficiency and heat transfer ratio predicted at the matching point of the hydrogen internal combustion engine in combination with the constant-pressure specific heat capacity of the mixed gas, when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold value, the set exhaust temperature at the turbine inlet is the determined exhaust temperature at the turbine inlet; a fifth calculation unit, for determining the turbine expansion ratio of the supercharger based on the determined exhaust temperature at the turbine inlet in combination with the parameters of the compressor of the supercharger.

[0039] A third aspect of the present application provides a supercharged hydrogen internal combustion engine, comprising a hydrogen internal combustion engine and a supercharger, wherein the supercharger comprises a turbine and a compressor, wherein the turbine and the compressor are arranged in linkage, wherein the turbine is coupled to the exhaust side of the hydrogen internal combustion engine, and the compressor is coupled to the air intake side of the hydrogen internal combustion engine, and wherein the supercharger is selected using the method for selecting a supercharger for a supercharged hydrogen internal combustion engine described in any one of the first aspects.

[0040] A fourth aspect of the present application provides a computing device comprising a memory and a processor, wherein: the memory stores program instructions, and when the program instructions are executed by the processor, the processor executes the method for selecting a supercharger for a supercharged hydrogen internal combustion engine as described in any one of the first aspects.

[0041] A fifth aspect of the present application provides a computer-readable storage medium having program instructions stored thereon, wherein when the program instructions are executed by a computer, the computer executes the method for selecting a supercharger for a supercharged hydrogen internal combustion engine as described in any one of the first aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the principle of a supercharged hydrogen internal combustion engine;

[0043] Figure 2 A flow chart of a first embodiment of a method for selecting a supercharger for a supercharged hydrogen internal combustion engine;

[0044] Figure 3 A flow chart of a second embodiment of a method for selecting a supercharger for a supercharged hydrogen internal combustion engine;

[0045] Figure 4A structural schematic diagram of a supercharger selection device for a supercharged hydrogen internal combustion engine;

[0046] Figure 5 A schematic diagram of the structure of a computing device.

[0047] It should be understood that the size and shape of each block diagram in the above structural diagram are for reference only and should not constitute an exclusive interpretation of the embodiments of the present application. The relative positions and inclusion relationships between the blocks presented in the structural diagram are only schematic representations of the structural associations between the blocks, and do not limit the physical connection methods of the embodiments of the present application. DETAILED DESCRIPTION

[0048] It should be understood that the selection scheme of the supercharger of the supercharged hydrogen internal combustion engine provided in the embodiment of the present application includes the selection method of the supercharger of the supercharged hydrogen internal combustion engine, the selection device, the supercharged hydrogen internal combustion engine, the computing device and the computer-readable storage medium, etc. Since the principles of solving the problems in these technical solutions are the same or similar, in the introduction of the following specific embodiments, some repetitions may not be repeated, but it should be regarded that these specific embodiments have been referenced to each other and can be combined with each other.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application. In the event of any inconsistency, the meaning described in this specification or the meaning derived from the contents recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application. In order to accurately describe the technical content in this application and to accurately understand the present invention, the following explanations or definitions are given to the terms used in this specification before describing the specific embodiments:

[0050] 1) Hydrogen internal combustion engine: refers to an internal combustion engine that uses hydrogen as fuel. It drives the piston to reciprocate by mixing hydrogen and air and then burning them. The piston pushes the connecting rod, which drives the crankshaft to rotate, thereby outputting rotational power. Different from hydrogen fuel cells, hydrogen fuel cells are power generation devices that directly convert the chemical energy of hydrogen and oxygen into electrical energy.

[0051] 2) External injection hydrogen internal combustion engine, direct injection hydrogen internal combustion engine: The hydrogen nozzle of the external injection hydrogen internal combustion engine is located outside the cylinder of the hydrogen internal combustion engine, usually in the intake manifold of the cylinder of the hydrogen internal combustion engine. The direct injection hydrogen internal combustion engine, referred to as direct injection hydrogen internal combustion engine, has a hydrogen nozzle that extends directly into the cylinder of the hydrogen internal combustion engine.

[0052] 3) Supercharged hydrogen internal combustion engine, a hydrogen internal combustion engine including an air intake supercharging device, where the supercharging device is referred to as a supercharger.

[0053] See also Figure 1A schematic diagram of the supercharging principle of a supercharged hydrogen internal combustion engine schematically shown in the figure, wherein a supercharger is included, which has two coaxial turbines, one of which is located on the exhaust side of the hydrogen internal combustion engine, usually also referred to as the turbine of the supercharger (if there is no special explanation, when the turbine is mentioned later, it refers to the turbine located on the exhaust side of the hydrogen internal combustion engine), and the other turbine is located on the air intake side of the hydrogen internal combustion engine, usually also referred to as the compressor of the supercharger (if there is no special explanation, when the compressor is mentioned later, it refers to the turbine located on the intake side of the hydrogen internal combustion engine). The exhaust gas generated after the combustion of the mixed gas in the cylinder of the hydrogen internal combustion engine is discharged through the exhaust port, and the exhaust drives the turbine of the supercharger to rotate, driving the coaxial compressor to rotate, so that the compressor drives the air to actively enter the intake port of the hydrogen internal combustion engine, that is, to realize the air supercharging on the intake side to enter the hydrogen internal combustion engine. Among them, the matching degree of the compressor and the turbine will affect the matching quality of the entire supercharger and the hydrogen internal combustion engine.

[0054] 4) Matching point of hydrogen internal combustion engine: This refers to the target parameters corresponding to the hydrogen internal combustion engine under a certain operating point. The matching point is determined based on the target requirements of different hydrogen internal combustion engines. The target parameters may include target power, target effective thermal efficiency, etc.

[0055] For example, an indicator of a hydrogen internal combustion engine is to achieve a target power of 80 kW at an operating point of 3000 rpm, and the 80 kW is one of the target parameters at this operating point.

[0056] For another example, an indicator of a hydrogen internal combustion engine is to achieve a target effective thermal efficiency of 40% at an operating point of 2000 rpm and a mean effective pressure of 1 MPa, and the 40% is one of the target parameters at this operating point.

[0057] 5) NIST database: This refers to the NIST Chemistry WebBook, which is the chemical part of the standard reference database of the National Institute of Standards and Technology (NIST).

[0058] 6) Excess air coefficient: refers to the ratio of the actual amount of air supplied for fuel combustion to the theoretical amount of air. It is a parameter that reflects the fuel-air ratio.

[0059] The embodiment of the present application is used for selecting a supercharger of a supercharged hydrogen internal combustion engine, wherein the supercharged hydrogen internal combustion engine includes a selected supercharger, and the supercharged hydrogen internal combustion engine can be applied to a vehicle and used as a power output device of the vehicle, and the power output device can be an engine, and the vehicle is such as a vehicle, a ship, an aircraft, etc. It is not difficult to understand that the supercharged hydrogen internal combustion engine can also be applied to other devices requiring power, such as pumps, generators, etc.

[0060] When selecting the turbine of the supercharger of the supercharged hydrogen internal combustion engine, the main parameters of concern are the flow rate and expansion ratio of the turbine of the supercharger, and the pressure ratio between the inlet and outlet of the turbine. When recalculating the constant pressure specific heat capacity and adiabatic index physical parameters of the exhaust gas, it is necessary to consider the influence of the exhaust gas components on it; at the same time, the exhaust temperature at the inlet of the turbine also has a great influence on these parameters. In the process of selecting the turbine for the supercharger of the supercharger of the supercharger of the hydrogen internal combustion engine, on the one hand, it is necessary to consider the difference in exhaust gas components after hydrogen combustion, and at the same time, it is necessary to introduce a correction method with sufficient accuracy to correct the exhaust gas temperature at the inlet of the turbine to ensure that the expansion ratio calculation result is as accurate as possible. Among them, the present application calculates the exhaust gas temperature at the inlet of the supercharger turbine, combines the target boost pressure set by the matching point, the specific heat capacity of the exhaust gas at the inlet of the turbine and the adiabatic index, and obtains the expansion ratio of the turbine, so as to achieve a good selection of the turbine for the supercharger of the supercharger of the hydrogen internal combustion engine, and obtains a more accurate result by correcting the iterative calculation of the exhaust gas temperature at the inlet of the turbine. The turbine of the supercharger selected in this way can be well matched with its compressor, and the supercharger selected in this way can be well matched with the hydrogen internal combustion engine. The present application will be described in detail below in conjunction with the accompanying drawings.

[0061] like Figure 2 The first embodiment of a supercharger selection method for a supercharged hydrogen internal combustion engine provided by an embodiment of the present application is shown, wherein the method of the embodiment of the present application is applicable to both an out-of-cylinder injection hydrogen internal combustion engine and an in-cylinder direct injection hydrogen internal combustion engine. The present application estimates the temperature and expansion ratio at the turbine inlet of the supercharger used by using the target parameters and empirical values ​​predetermined by the matching point of the hydrogen internal combustion engine, and obtains a more accurate result by correcting the exhaust temperature at the turbine inlet. The supercharger selection method includes the following steps:

[0062] S10: Calculate the air flow rate and the hydrogen flow rate according to the hydrogen internal combustion engine matching point and the given excess air coefficient.

[0063] In some embodiments, the calculation can be performed with reference to formula (1.1) to formula (1.3) described later.

[0064] S20: Calculate the mass fraction ω of the exhaust component of the hydrogen internal combustion engine according to the chemical equation of the reaction of hydrogen and air in combination with the excess air coefficient λ.

[0065] In some embodiments, the chemical equation for the reaction of hydrogen and air can refer to the formula (2.1) described below. The mass fraction ω of the exhaust component of the hydrogen internal combustion engine can be calculated by referring to the formulas (2.2) to (2.4) described below.

[0066] In some embodiments, the mass fraction of each exhaust component may be calculated based on a chemical equation for the reaction of hydrogen and air.

[0067] S30: Set the exhaust temperature T at the turbine inlet t1 , combined with the mass fraction of the exhaust gas components, calculate the constant pressure specific heat capacity C of the mixed gas constituting the exhaust gas pmix .

[0068] In some embodiments, during the calculation process, the constant pressure specific heat capacity C corresponding to each exhaust component required for calculation can be obtained by querying p , for example, can be queried in the NIST database.

[0069] In some embodiments, the calculation may be performed with reference to formula (3) described below.

[0070] S40: The target effective thermal efficiency η predicted based on the matching point of the hydrogen internal combustion engine and the empirical parameter η of the heat transfer ratio under the corresponding working conditions cooling , and the constant pressure specific heat capacity C of the mixed gas p mix , calculate the theoretical value of exhaust temperature T at the turbine inlet t2 , when T t2 and the set exhaust temperature T t1 When the difference is within the error threshold, the T t1 is the determined exhaust gas temperature at the turbine inlet.

[0071] In some embodiments, T t2 It can be calculated by referring to the formula (4) described later.

[0072] S50: Based on the determined exhaust gas temperature T at the turbine inlet t1 , combined with the parameters of the supercharger's compressor, the expansion ratio of the supercharger's turbine is calculated.

[0073] In some embodiments, the expansion ratio of the turbine of the supercharger may be calculated with reference to formula (5.1) to formula (8) described below.

[0074] In some embodiments, based on the set exhaust gas temperature T at the turbine inlet t1 The physical parameters of the exhaust gas at the turbine inlet under different conditions are calculated based on parameters such as exhaust gas components and specific heat capacity of each component at the corresponding temperature. The method involves the gas state equation and the mass equation, simplifies the gas in the cylinder into an ideal gas, and takes into account the influence of temperature on the specific heat capacity of the gas at constant pressure.

[0075] In some embodiments, based on the calculated physical parameters of the exhaust gas at the turbine inlet, combined with the preset effective thermal efficiency of the hydrogen internal combustion engine matching point, and the empirical parameters of the heat transfer ratio and intake-related parameters, the theoretical value of the exhaust gas temperature at the turbine inlet is calculated, and the method involves thermodynamic equations.

[0076] In some embodiments, the turbine expansion ratio is calculated based on the relationship between the conservation of mass and the conservation of energy of the turbine compressor, combined with parameters such as the pressure ratio provided by the hydrogen internal combustion engine compressor and the efficiency of the supercharger.

[0077] In some embodiments, for the above step S40, when T t2 and the set exhaust temperature T t1 If the difference is not within the error threshold, T can be adjusted. t1 , that is, reset the exhaust temperature T t1 , and repeat steps S30 and S40 until the turbine inlet temperature T t2 and the exhaust gas temperature T at the turbine inlet t1 If the values ​​are equal or the difference is within the allowable error range, the obtained temperature is the exhaust gas temperature at the turbine inlet that is finally determined.

[0078] In order to better understand this application, see further below. Figure 3 The flowchart shown introduces a second embodiment of a method for selecting a supercharger for a supercharged hydrogen internal combustion engine provided in an embodiment of the present application, comprising the following steps:

[0079] S110: Determine the matching point of the hydrogen internal combustion engine, and then calculate the air flow rate and the hydrogen flow rate according to the matching point of the hydrogen internal combustion engine and the given excess air coefficient, as follows:

[0080] In the development process of hydrogen internal combustion engines, relevant target parameters need to be given in advance, including target power and target effective thermal efficiency, that is, matching points are given in advance. The target parameters are determined according to the predetermined indicators for the development of hydrogen internal combustion engines. For example, the target parameters can be: it is expected to achieve a target power of 75kW and a target effective thermal efficiency of 40% under the conditions of a hydrogen internal combustion engine speed of 2000rpm and a mean effective pressure of 1MPa.

[0081] Then, the flow rates of air and hydrogen and the total gas flow rate can be calculated according to the target power and target effective thermal efficiency of a given hydrogen internal combustion engine at a certain operating point using the following formulas (1.1) to (1.3).

[0082]

[0083]

[0084] M T =M H +M C (1.3)

[0085] Among them, M C is the air flow rate; M H is the hydrogen flow rate; MT is the total gas flow rate; P e is the target power; H u is the calorific value of hydrogen; η is the target effective thermal efficiency; L0 is the theoretical amount of air required for complete combustion of one kilogram of hydrogen; λ is the given excess air coefficient.

[0086] S115: Calculate the mass fraction ω of each component of the exhaust gas after the combustion reaction of hydrogen and air entering the hydrogen internal combustion engine, which can be calculated by the following formulas (2.1) to (2.4):

[0087] 2H2+λO2+3.71λN2=2H2O+(λ-1)O2+3.71·λN2 (2.1)

[0088]

[0089]

[0090]

[0091] Among them, H2 is hydrogen; O2 is oxygen; N2 is nitrogen; H2O is water, which here means water vapor;

[0092] Formula (2.1) is the chemical equation for the combustion reaction of hydrogen and air. The left side of the equal sign represents the intake gas composition of the hydrogen internal combustion engine, and the right side of the equal sign represents the exhaust gas composition of the hydrogen internal combustion engine. The 3.71 in the formula is the ratio of the nitrogen content to the oxygen content in the air.

[0093] In the above formula, represents the mass fraction of water vapor in the exhaust gas of a hydrogen internal combustion engine, Represents the oxygen mass fraction in the exhaust gas of a hydrogen internal combustion engine; Represents the mass fraction of nitrogen in the exhaust gas of a hydrogen internal combustion engine.

[0094] S120-S125: Assume that the exhaust temperature at the turbine inlet of the supercharger used in the hydrogen internal combustion engine (i.e., the exhaust temperature of the hydrogen internal combustion engine) T t1 , query the constant pressure specific heat capacity C corresponding to each exhaust component in the NIST database p , calculate the constant pressure specific heat capacity C of the mixed gas constituting the exhaust gas p mix .

[0095] Among them, temperature is the factor that affects C p The main factor, pressure on C p The impact is small, the pressure can be taken as 2.5 bar, so the exhaust temperature T can be queried t1 , the constant pressure specific heat capacity of each exhaust gas component under the pressure of 2.5 bar. The constant pressure specific heat capacity of the mixed gas C p mixIt can be calculated by the following formula (3):

[0096]

[0097] in: is the constant pressure specific heat capacity of water vapor; is the constant pressure specific heat capacity of oxygen; is the constant pressure specific heat capacity of nitrogen.

[0098] S130: According to the target effective thermal efficiency η in the hydrogen internal combustion engine matching point (see step S110), and the heat transfer ratio η under the corresponding working condition cooling , calculate the theoretical value of the exhaust temperature T at the turbine inlet of the supercharger t2 , can be calculated by the following formula (4):

[0099]

[0100] Where: η cooling is the heat transfer ratio, which can be an empirical parameter, C p intake is the constant-pressure specific heat capacity of the air intake after the hydrogen internal combustion engine compressor (i.e., the air intake of the hydrogen internal combustion engine), where the temperature does not change greatly, and can be taken as 1.004 kJ / (kg·K) based on experience; T C2 for Figure 1 The temperature of the intake air after passing through the intercooler (which can also be understood as the temperature of the air when it enters the internal combustion engine) can be obtained by using a temperature sensor in a preliminary experiment, or determined based on empirical data, for example, a value of 40°C can be taken.

[0101] S135-S140: Compare the assumed value T of the exhaust gas temperature at the turbine inlet of the supercharger t1 Compared with the calculated theoretical value T t2 , when the difference between the two is within the allowable error range, the temperature T t1 This is the exhaust temperature at the turbine inlet of the supercharger. If it is not within the allowable error range, adjust the exhaust temperature T t1 (For example, the exhaust temperature T can be adjusted downward t1 ) and returns to step S120.

[0102] By cyclically executing the above steps S120 to S140, the calculation accuracy of the exhaust temperature at the inlet of the turbine of the supercharger can be improved, and the calculation accuracy of the turbine expansion ratio in the following steps can also be improved.

[0103] S145: Finally, the exhaust temperature T at the inlet of the turbocharger turbine is determined by the theoretical calculation formula of the turbine expansion ratio. t1 , Combined with the parameters of the compressor of the supercharger, calculate the turbine expansion ratio. The details are as follows:

[0104] The compressor power P of the supercharger L With turbine power P T The relationship between , we can get the following formulas (5.1) to (5.5):

[0105] P L =P T (5.1)

[0106]

[0107]

[0108]

[0109]

[0110] in: is the gas flow rate through the compressor; Δh sL is the isentropic enthalpy difference of the compressor; η sL is the isentropic efficiency of the compressor; η mL is the mechanical efficiency of the compressor; T C1 is the air inlet temperature at the compressor inlet (or the gas temperature before the compressor), which is generally 300K; 2t is the pressure at the compressor outlet; p 1t is the pressure at the compressor inlet; κL is the adiabatic index of the gas in the compressor; is the gas flow rate through the turbine; Δh sT is the isentropic enthalpy difference of the turbine; η sT is the isentropic efficiency of the turbine; η mT is the mechanical efficiency of the turbine; p 4t is the pressure at the turbine outlet; p 3t is the pressure at the turbine inlet; κT is the adiabatic index of the gas in the turbine.

[0111] According to formula (5.1) to formula (5.5), the following formula (6) can be derived:

[0112]

[0113] Among them, η TL represents the overall turbocharger efficiency, η TL It can be calculated by the following formula (7):

[0114] η TL =η sL ·η mL ·η sT ·η mT (7)

[0115] Then, combining formula (6) and formula (7), the following calculation formula for the turbine expansion ratio can be derived:

[0116]

[0117] Then, the total gas flow M obtained in step S110 can be used to calculate the total gas flow M. T and the turbine expansion ratio obtained in step S145 By selecting the turbine of the supercharger, the selection of the supercharger for the hydrogen internal combustion engine is completed.

[0118] Here, it is explained that among the above parameters, the air flow rate M C and hydrogen flow rate M H , the adiabatic index κT of the gas in the turbine, the constant pressure specific heat C of the mixed gas composed of the exhaust gas at the turbine inlet p mix and the exhaust gas temperature at the turbine inlet T t1 and expansion ratio It can be calculated by the above corresponding formula. Among them, the air flow rate M C and hydrogen flow rate M H It can also be obtained directly through experimental testing.

[0119] In addition, the target effective thermal efficiency η, heat transfer ratio η cooling , Intake air constant pressure specific heat C p intake , the adiabatic index of the gas in the compressor κL and the overall turbocharger efficiency η TL , the temperature of the air after passing through the intercooler T C2 It can be set based on experience or obtained by querying relevant standard databases, historical data, etc.

[0120] like Figure 4 As shown, the embodiment of the present application also provides a corresponding device for selecting a supercharger of a supercharged hydrogen internal combustion engine. For the beneficial effects or technical problems solved by the device, please refer to the description of the methods corresponding to each device, or refer to the description in the content of the invention. Only a brief description is given here. The calibration device in this embodiment can be used to implement the various optional embodiments in the above-mentioned selection method.

[0121] like Figure 4 The supercharger selection device of the supercharged hydrogen internal combustion engine shown includes:

[0122] The first calculation unit 10 is used to calculate the air flow rate and the hydrogen flow rate according to the hydrogen internal combustion engine matching point and a given excess air coefficient, and is specifically used to implement the above step S10 and its optional embodiments.

[0123] The second calculation unit 20 is used to calculate the mass fraction of exhaust components of the hydrogen internal combustion engine according to the chemical equation of the reaction between hydrogen and air and in combination with the excess air coefficient, and is specifically used to implement the above step S20 and its optional embodiments.

[0124] The third calculation unit 30 is used to set the exhaust temperature at the turbine inlet of the supercharger, and determine the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature in combination with the mass fraction of the exhaust gas component, and is specifically used to implement the above step S30 and its optional embodiments.

[0125] The fourth calculation unit 40 is used to calculate the theoretical value of the exhaust temperature at the turbine inlet according to the target effective thermal efficiency and heat transfer ratio predicted by the hydrogen internal combustion engine matching point, combined with the constant pressure specific heat capacity of the mixed gas, and when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold, the set exhaust temperature at the turbine inlet is the determined exhaust temperature at the turbine inlet. Specifically used to implement the above step S40 and its optional embodiments.

[0126] The fifth calculation unit 50 is used to determine the turbine expansion ratio of the supercharger based on the determined exhaust gas temperature at the turbine inlet and in combination with the parameters of the compressor of the supercharger, and is specifically used to implement the above step S50 and its optional embodiments.

[0127] The embodiment of the present application also provides a supercharged hydrogen internal combustion engine, including a hydrogen internal combustion engine and a supercharger, wherein the supercharger includes a turbine and a compressor, wherein the turbine and the compressor are arranged in linkage, such as coaxially, wherein the turbine is coupled to the exhaust side of the hydrogen internal combustion engine, and the compressor is coupled to the air intake side of the hydrogen internal combustion engine. The supercharger used in the hydrogen internal combustion engine is selected using the supercharger selection method for the hydrogen internal combustion engine.

[0128] Figure 5 is a schematic structural diagram of a computing device 900 provided in an embodiment of the present application. Figure 5 As shown, the computing device 900 includes: a processor 910 , a memory 920 , and a communication interface 930 .

[0129] It should be understood that Figure 5 The communication interface 930 in the computing device 900 shown may be used to communicate with other devices, and may specifically include one or more transceiver circuits or interface circuits.

[0130] The processor 910 may be connected to a memory 920. The memory 920 may be used to store the program code and data. Therefore, the memory 920 may be a storage unit inside the processor 910, or an external storage unit independent of the processor 910, or a component including a storage unit inside the processor 910 and an external storage unit independent of the processor 910.

[0131] Optionally, the computing device 900 may further include a bus. The memory 920 and the communication interface 930 may be connected to the processor 910 via the bus. The bus may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 A line without an arrow is used to represent the bus, but this does not mean that there is only one bus or one type of bus.

[0132] It should be understood that in the embodiment of the present application, the processor 910 may adopt a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. Alternatively, the processor 910 may adopt one or more integrated circuits to execute relevant programs to implement the technical solutions provided in the embodiment of the present application.

[0133] The memory 920 may include a read-only memory and a random access memory, and provides instructions and data to the processor 910. A portion of the processor 910 may also include a nonvolatile random access memory. For example, the processor 910 may also store information on the device type.

[0134] When the computing device 900 is running, the processor 910 executes the computer-executable instructions in the memory 920 to perform any operation step of the above method and any optional embodiment thereof.

[0135] It should be understood that the computing device 900 according to the embodiment of the present application can correspond to the corresponding subjects in the methods according to the embodiments of the present application, and the above-mentioned and other operations and / or functions of each module in the computing device 900 are respectively for realizing the corresponding processes of each method of the present embodiment, which will not be repeated here for the sake of brevity.

[0136] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0137] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0138] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0139] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0140] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0141] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0142] An embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, it is used for the above method, and the method includes at least one of the solutions described in the above embodiments.

[0143] The computer storage medium of the embodiment of the present application can adopt any combination of one or more computer-readable media. Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above. More specific examples (non-exhaustive lists) of computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, computer-readable storage media can be any tangible medium containing or storing programs, which can be used by instruction execution systems, devices or devices or used in combination with them.

[0144] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0145] The program code embodied on the computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0146] Computer program code for performing the operation of the present application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (e.g., using an Internet service provider to connect through the Internet).

[0147] In addition, the words "first, second, third, etc." or module A, module B, module C and other similar terms in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that the specific order or sequence can be interchanged where permitted so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0148] In the above description, the numbers representing the steps, such as S110, S120, etc., do not necessarily mean that the steps will be executed in this manner. If permitted, the order of the steps can be interchanged or they can be executed simultaneously.

[0149] The term "comprising" as used in the description and claims should not be interpreted as being limited to what is listed thereafter; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the features, integers, steps or components mentioned, but does not exclude the presence or addition of one or more other features, integers, steps or components and groups thereof. Therefore, the expression "a device comprising means A and B" should not be limited to a device consisting of components A and B only.

[0150] References to "one embodiment" or "an embodiment" in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the particular features, structures, or characteristics can be combined in any appropriate manner, as would be apparent to one of ordinary skill in the art from this disclosure.

[0151] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present application, all of which belong to the scope of protection of the present application.

Claims

1. A method for selecting a supercharger for a supercharged hydrogen internal combustion engine, characterized in that: include: Calculating the air flow rate and the hydrogen flow rate according to a predetermined target power of the hydrogen internal combustion engine, a predetermined target effective thermal efficiency and a given excess air coefficient; Calculate the mass fraction of exhaust components of the hydrogen internal combustion engine according to the chemical equation of the reaction between hydrogen and air and in combination with the excess air coefficient; Setting the exhaust gas temperature at the turbine inlet of the supercharger, and determining the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature in combination with the mass fraction of the exhaust gas components; The theoretical value of the exhaust temperature at the turbine inlet is calculated according to the predetermined target effective thermal efficiency and heat transfer ratio of the hydrogen internal combustion engine and the constant-pressure specific heat capacity of the mixed gas. When the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold value, the set exhaust temperature at the turbine inlet is the determined exhaust temperature at the turbine inlet. Based on the determined exhaust gas temperature at the turbine inlet and in combination with the parameters of the compressor of the supercharger, the turbine expansion ratio of the supercharger is determined.

2. The method according to claim 1, characterized in that When the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is not within the threshold, the set exhaust temperature at the turbine inlet is adjusted, the constant-pressure specific heat capacity of the exhaust mixed gas is re-determined, and the theoretical value of the exhaust temperature at the turbine inlet is recalculated.

3. The method according to claim 1 or 2, characterized in that: The air flow rate and hydrogen flow rate are calculated according to the following formula: Among them, M C is the air flow rate; M H is the hydrogen flow rate; P e is the target power of the hydrogen internal combustion engine; H u is the calorific value of hydrogen; η is the target effective thermal efficiency of the hydrogen internal combustion engine; L0 is the theoretical amount of air required for complete combustion of one kilogram of hydrogen; λ is the excess air coefficient.

4. The method according to claim 3, characterized in that The chemical equation for the reaction of hydrogen and air is: 2H2+λO2+3.71λN2=2H2O+(λ-1)O2+3.71·λN2; The mass fraction of exhaust components of a hydrogen internal combustion engine is calculated according to the following formula: Among them, H2 is hydrogen; O2 is oxygen; N2 is nitrogen; H2O is water, which here means water vapor; represents the mass fraction of water vapor in the exhaust gas of a hydrogen internal combustion engine, Represents the oxygen mass fraction in the exhaust gas of a hydrogen internal combustion engine; Represents the mass fraction of nitrogen in the exhaust gas of a hydrogen internal combustion engine.

5. The method according to claim 4, characterized in that The constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature is determined by calculating according to the following formula: Where: C p mix is the constant pressure specific heat capacity of the mixed gas; is the constant pressure specific heat capacity of water vapor; is the constant pressure specific heat capacity of oxygen; is the constant pressure specific heat capacity of nitrogen.

6. The method according to claim 5, characterized in that The theoretical value of the exhaust temperature at the turbine inlet is calculated according to the following formula: Where: T t2 is the theoretical value of exhaust temperature at turbine inlet; η cooling is the heat transfer ratio, C p intake is the constant pressure specific heat capacity of the intake air; T C2 It is the temperature of the intake air after passing through the intercooler.

7. The method according to claim 6, characterized in that The turbine expansion ratio of the supercharger is determined by calculating according to the following formula: Among them, h TL =the sL ·or mL ·or sT ·or mT in: is the turbine expansion ratio of the supercharger; p 4t is the pressure at the turbine outlet; p 3t is the pressure at the turbine inlet; p 2t is the pressure at the compressor outlet; p 1t is the pressure at the compressor inlet; κL is the adiabatic index of the gas in the compressor; is the gas flow rate through the compressor; is the gas flow rate through the turbine; T C1 is the intake air temperature at the compressor inlet; T t1 is the determined exhaust temperature at the turbine inlet; κT is the adiabatic index of the gas in the turbine; η TL Represents the overall turbocharger efficiency; η sL is the isentropic efficiency of the compressor; η mL is the mechanical efficiency of the compressor; η sT is the isentropic efficiency of the turbine; η mT is the mechanical efficiency of the turbine.

8. A device for selecting a supercharger for a supercharged hydrogen internal combustion engine, characterized in that: include: A first calculation unit is used to calculate the air flow rate and the hydrogen flow rate according to a predetermined target power of the hydrogen internal combustion engine, a predetermined target effective thermal efficiency and a given excess air coefficient; A second calculation unit is used to calculate the mass fraction of exhaust components of the hydrogen internal combustion engine according to the chemical equation of the reaction between hydrogen and air in combination with the excess air coefficient; A third calculation unit is used to set the exhaust gas temperature at the turbine inlet of the supercharger, and determine the constant-pressure specific heat capacity of the mixed gas constituting the exhaust gas at the set exhaust temperature in combination with the mass fraction of the exhaust gas components; a fourth calculation unit, for calculating the theoretical value of the exhaust temperature at the turbine inlet according to the predetermined target effective thermal efficiency and heat transfer ratio of the hydrogen internal combustion engine and the constant-pressure specific heat capacity of the mixed gas; when the difference between the theoretical value of the exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold value, the set exhaust temperature at the turbine inlet is the determined exhaust temperature at the turbine inlet; The fifth calculation unit is used to determine the turbine expansion ratio of the supercharger based on the determined exhaust gas temperature at the turbine inlet and in combination with the parameters of the compressor of the supercharger.

9. A supercharged hydrogen internal combustion engine, characterized in that: Including hydrogen internal combustion engines and superchargers, The supercharger includes a turbine and a compressor, the turbine and the compressor are arranged in linkage, the turbine is coupled to the exhaust side of the hydrogen internal combustion engine, and the compressor is coupled to the air intake side of the hydrogen internal combustion engine. The supercharger is selected using the method for selecting a supercharger for a supercharged hydrogen internal combustion engine according to any one of claims 1 to 7.

10. A computing device, characterized in that It includes a memory and a processor, wherein: The memory stores program instructions, which, when executed by the processor, enable the processor to execute the method for selecting a supercharger for a supercharged hydrogen internal combustion engine according to any one of claims 1 to 7.

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