Air intake amount acquisition method for hydrogen fuel engine and hydrogen fuel engine system

Abstract

The application discloses a hydrogen fuel engine air intake amount acquisition method and a hydrogen fuel engine system, and relates to the technical field of engine control. The hydrogen fuel engine air intake amount acquisition method comprises the following steps: acquiring a hydrogen injection amount; acquiring a hydrogen consumption amount according to a first parameter; wherein the first parameter comprises the hydrogen injection amount; acquiring a fresh air intake amount according to a second parameter; wherein the second parameter comprises the hydrogen consumption amount, and the fresh air intake amount is the total amount of gas entering the hydrogen fuel engine. The hydrogen fuel engine air intake amount acquisition method provided by the embodiment of the application acquires the fresh air intake amount entering the hydrogen fuel engine through the hydrogen consumption amount, is not affected by environmental factors, is not affected by the working condition change of the hydrogen fuel engine, can obtain more accurate air intake amount, and simultaneously, the air intake amount acquisition method of the application does not need to calibrate the air intake efficiency, does not need to set a flowmeter, improves the acquisition efficiency, reduces the cost, and reduces the error caused by heavy workload.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, and in particular to an air intake amount acquisition method of a hydrogen fuel engine and a hydrogen fuel engine system. BACKGROUND

[0002] The existing theoretical air intake amount formula of an engine needs to measure the intake pressure, intake temperature and engine speed in real time. However, in a hydrogen injection engine, the hydrogen entering the intake passage will increase the intake pressure, at which time the air entering the intake passage will decrease, the hydrogen partial pressure needs to be subtracted when calculating the intake pressure, and the air-fuel ratio will change constantly and the hydrogen partial pressure is not fixed, so the hydrogen partial pressure cannot be calculated. There is intake throttling loss at the bends, throttle valves and intake valves in the engine intake pipeline, and the actual air intake amount cannot reach the theoretical air intake amount. However, the calculation of the actual air intake amount needs the intake efficiency, which needs to be obtained according to the engine speed and intake pressure signal to obtain the intake efficiency of the current working condition, and then multiplied by the theoretical air intake amount to obtain the actual air intake amount, which has high cost and large error.

[0003] An engine using the exhaust gas recirculation (EGR) technology sends part of the exhaust gas of the engine back to the intake manifold and enters the cylinder again with fresh mixture. The calculated actual air intake amount includes the air intake amount of fresh air and the air intake amount of exhaust gas, so the proportion of the two parts needs to be calculated. There are usually two methods for calculating the air intake amount of the EGR engine: as shown in FIG. 1, a fresh air intake amount is collected by using an air intake sensor 2, however, the air flow meter is expensive and not suitable for large displacement engines. As shown in FIG. 2, the exhaust gas flow is calculated by using a Venturi flow meter 3 and Bernoulli equation, which has the problem of flow meter throttling loss and high cost. Figure 1 Figure 2 Therefore, the air intake amount calculation method of the traditional engine and the exhaust gas flow calculation method of the EGR engine are not suitable for the hydrogen injection engine, which has the disadvantages of large workload, flow meter throttling loss, high cost and the like.

[0004] Therefore, the air intake amount calculation method of the traditional engine and the exhaust gas flow calculation method of the EGR engine are not suitable for the hydrogen injection engine, which has the disadvantages of large workload, flow meter throttling loss, high cost and the like. SUMMARY

[0005] The present application provides an air intake amount acquisition method of a hydrogen fuel engine and a hydrogen fuel engine system, which is not affected by the working condition change of the hydrogen fuel engine, can obtain more accurate air intake amount, improve the acquisition efficiency, reduce the cost and reduce the error caused by large workload.

[0006] According to an aspect of the present application, an air intake amount acquisition method of a hydrogen fuel engine is provided, comprising:

[0007] acquiring a hydrogen injection amount; ​

[0008] The hydrogen consumption is obtained based on the first parameter; wherein the first parameter includes the hydrogen injection volume.

[0009] The fresh air intake is obtained based on the second parameter; wherein the second parameter includes the hydrogen consumption, and the fresh air intake is the total amount of gas entering the hydrogen fuel cell engine.

[0010] Optionally, the second parameter also includes exhaust oxygen concentration;

[0011] Before obtaining the fresh intake air volume based on the second parameter, the following steps are also included:

[0012] Obtain the oxygen concentration in the exhaust gas.

[0013] Optionally, the first parameter may further include the number of cylinders, engine speed, and number of working cycles;

[0014] Wherein, the number of cylinders is the number of cylinders in the hydrogen fuel cell engine, and the number of working cycle revolutions is the number of crankshaft revolutions in one working cycle of the hydrogen fuel cell engine.

[0015] Optionally, after obtaining the fresh intake air volume based on the second parameter, the method further includes:

[0016] Based on the third parameter and the fresh air intake, the corrected fresh air intake is obtained;

[0017] The third parameter includes at least one of the following: unburned hydrogen corrected intake volume, nitrogen oxide corrected intake volume, and humidity corrected intake volume.

[0018] Optionally, before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes:

[0019] Obtain the concentration of hydrogen in the exhaust gas;

[0020] The unburned hydrogen corrected intake volume is obtained based on the exhaust hydrogen concentration, the fresh intake volume, and the hydrogen consumption.

[0021] Optionally, before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes:

[0022] Obtain the concentration of nitrogen oxides in exhaust gas;

[0023] The nitrogen oxide-corrected intake volume is obtained based on the exhaust nitrogen oxide concentration, the fresh intake volume, and the hydrogen consumption.

[0024] Optionally, before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes:

[0025] The moisture content of dry air can be obtained by referring to a table based on environmental pressure, temperature, and relative humidity.

[0026] The humidity-corrected intake volume is obtained based on the fresh intake volume and the moisture content of the dry air obtained from the table.

[0027] Optionally, after obtaining the fresh intake air volume based on the second parameter, the method further includes:

[0028] Based on the fourth parameter, the exhaust gas flow rate and EGR rate are obtained; wherein, the EGR rate is the ratio of the exhaust gas flow rate to the total intake air volume of the intake cylinder, and the fourth parameter includes the fresh intake air volume.

[0029] Optionally, the fourth parameter also includes the intake oxygen concentration;

[0030] Before obtaining the exhaust gas flow rate and EGR rate based on the fourth parameter, the following steps are also included:

[0031] Obtain the intake oxygen concentration.

[0032] Optionally, after obtaining the exhaust gas flow rate and EGR rate based on the fresh intake air volume, the method further includes:

[0033] The total engine charge is obtained based on the fresh air intake, hydrogen consumption, and exhaust gas flow rate.

[0034] According to another aspect of the present invention, a hydrogen fuel engine system is provided, including a hydrogen fuel engine and an engine control unit;

[0035] The engine control unit implements the intake air quantity acquisition method for the hydrogen fuel cell engine as described above.

[0036] Optionally, the hydrogen fuel cell engine includes at least one of a plurality of sensors, the plurality of sensors including:

[0037] An intake oxygen sensor, located in the intake manifold of the hydrogen fuel cell engine, is used to obtain the intake oxygen concentration.

[0038] An exhaust oxygen sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the exhaust oxygen concentration;

[0039] A hydrogen concentration sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the exhaust hydrogen concentration.

[0040] A nitrogen oxide concentration sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the concentration of nitrogen oxides in the exhaust gas.

[0041] This invention provides a method for obtaining the intake air volume of a hydrogen fuel cell engine and a hydrogen fuel cell engine system. The method obtains the hydrogen consumption by measuring the hydrogen injection volume, and then obtains the fresh intake air volume entering the hydrogen fuel cell engine by measuring the hydrogen consumption. It is not affected by environmental factors or changes in the operating conditions of the hydrogen fuel cell engine, and can obtain a more accurate intake air volume. At the same time, the method of obtaining the intake air volume of this invention does not require calibration of the intake efficiency or the installation of a flow meter, thereby improving the acquisition efficiency, reducing costs, and minimizing errors caused by large workloads.

[0042] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of the first type of engine system in the prior art;

[0045] Figure 2 This is a schematic diagram of the structure of a second type of engine system in the prior art;

[0046] Figure 3 A flowchart illustrating a first method for obtaining the air intake volume of a hydrogen fuel cell engine, as provided in an embodiment of the present invention.

[0047] Figure 4 A flowchart illustrating a second method for obtaining the air intake volume of a hydrogen fuel cell engine, as provided in an embodiment of the present invention.

[0048] Figure 5 This is a graph showing the relationship between the concentration of hydrogen in a mixture of hydrogen and air and the concentration of nitrogen oxides.

[0049] Figure 6 This is a schematic diagram of a hydrogen fuel engine system provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] Example 1

[0053] Figure 3 The flowchart of the first method for obtaining the intake air volume of a hydrogen fuel cell engine provided in the embodiments of the present invention is shown below. Figure 3 This method can be executed by the hydrogen fuel cell engine system provided in this embodiment of the invention, which can be implemented by software and / or hardware. The method for obtaining the intake air volume of the hydrogen fuel cell engine specifically includes the following steps:

[0054] S110, Obtain the amount of hydrogen gas injected.

[0055] Hydrogen fuel cell engines use hydrogen as fuel. Since hydrogen contains no carbon, it does not produce carbon dioxide upon combustion, reducing pollution. Furthermore, hydrogen can be obtained from renewable energy sources such as solar and wind power. When used as fuel in an internal combustion engine, hydrogen readily achieves lean combustion, resulting in low pollutant emissions and high thermal efficiency. The hydrogen injection volume refers to the total amount of hydrogen injected into the hydrogen fuel cell engine via the hydrogen injector. This volume can be controlled by adjusting the pulse width of the hydrogen injector's current through the engine control unit.

[0056] S120. Obtain the hydrogen consumption based on the first parameter.

[0057] The first parameter includes the hydrogen injection rate, and the hydrogen consumption rate is the amount of hydrogen consumed per hour when the hydrogen fuel cell engine is operating. By obtaining the hydrogen consumption rate through the hydrogen injection rate, the intake air volume of the hydrogen fuel cell engine can be determined.

[0058] S130. Obtain the fresh intake air volume based on the second parameter.

[0059] The second parameter includes hydrogen consumption, while the fresh air intake is the total amount of gas entering the hydrogen fuel cell engine. In a hydrogen fuel cell engine, hydrogen and air burn in the cylinders, so the total amount of gas entering the engine can be obtained from the amount of hydrogen consumed.

[0060] The method for obtaining the intake air volume of a hydrogen fuel cell engine provided in this invention obtains the hydrogen consumption by measuring the hydrogen injection volume, and obtains the fresh intake air volume entering the hydrogen fuel cell engine by measuring the hydrogen consumption volume. It is not affected by environmental factors and is not affected by changes in the operating conditions of the hydrogen fuel cell engine, thus obtaining a more accurate intake air volume. At the same time, the method for obtaining the intake air volume of this invention does not require calibration of the intake efficiency or the installation of a flow meter, thereby improving the acquisition efficiency, reducing costs, and minimizing errors caused by a large workload.

[0061] Based on the above embodiments, Figure 4 This is a flowchart illustrating a second method for obtaining the air intake volume of a hydrogen fuel cell engine according to an embodiment of the present invention. Figure 4 The illustrated embodiment provides a detailed explanation of how to correct the fresh air intake volume to obtain a more accurate intake volume result. (Refer to...) Figure 4 The acquisition method provided in this embodiment of the invention includes:

[0062] S201, Obtain the amount of hydrogen gas injected.

[0063] S202. Obtain the hydrogen consumption based on the first parameter.

[0064] The first parameter also includes the number of cylinders, engine speed, and working cycle revolutions. The number of cylinders refers to the number of cylinders in the hydrogen fuel cell engine, and the working cycle revolutions are the number of crankshaft rotations in one working cycle of the hydrogen fuel cell engine. The engine speed can be obtained through a speed sensor installed in the hydrogen fuel cell engine, and the hydrogen consumption can be obtained using the following formula:

[0065]

[0066] Where H1 is the hydrogen injection rate (mg / str), H2 is the hydrogen consumption rate (kg / h), L is the number of cylinders, n is the engine speed (r / min), and a is the number of revolutions per working cycle.

[0067] As an example, with a hydrogen injection rate H1 of 22 mg / str, a cylinder number L of 4, an engine speed n of 3000 r / min, and an engine working cycle speed a of 2, the hydrogen consumption H2 can be calculated to be 7.92 kg / h.

[0068] S203, Obtain the oxygen concentration in the exhaust gas.

[0069] The exhaust oxygen concentration is the oxygen concentration in the exhaust gas. The exhaust oxygen concentration can be obtained by setting an exhaust oxygen sensor in the exhaust pipe. In other embodiments, it can also be obtained by a nitrogen oxide concentration sensor. This embodiment of the invention does not impose specific limitations on this.

[0070] S204. Obtain the fresh intake volume based on the second parameter.

[0071] The second parameter includes hydrogen consumption and exhaust oxygen concentration. Since hydrogen and oxygen burn to form water, according to the chemical reaction formula, burning 1 mol of hydrogen requires 0.5 mol of oxygen. Due to the law of conservation of mass and the principle of oxygen balance (i.e., the mass of intake gas equals the mass of exhaust gas, and the oxygen content in the intake gas equals the oxygen content in the exhaust gas), the fresh intake air volume can be obtained using the following formula:

[0072]

[0073] Through transformation, we can obtain:

[0074]

[0075] Where G1 is the fresh air intake (kg / h), H2 is the hydrogen consumption (kg / h), and M... H M is the molecular weight of hydrogen (kg / mol). A V1 represents the molecular weight of air (kg / mol), V2 represents the oxygen concentration in the air, and V3 represents the oxygen concentration in the exhaust gas.

[0076] For example, the oxygen concentration in the air, V1, is 21%, and the molecular weight of hydrogen, M... H It is 0.002 kg / mol, and the molecular weight of air is M. A The concentration is 0.029 kg / mol. In other embodiments, the oxygen concentration in the air can also be obtained by setting an intake oxygen sensor in the intake pipe of the hydrogen fuel engine. This embodiment of the invention does not impose specific limitations on this.

[0077] As an example, with a hydrogen consumption of H2 of 7.92 kg / h and an exhaust oxygen concentration of V2 of 8.94%, a fresh intake air volume of G1 of 482 kg / h can be obtained.

[0078] S205, Obtain the concentration of exhaust hydrogen.

[0079] The gas entering the hydrogen fuel cell engine consists of fresh air and hydrogen. After combustion, hydrogen and oxygen react to produce water, and a small amount of nitrogen and oxygen in the air react at high temperatures to form nitrogen oxides. The nitrogen, oxygen, and trace amounts of rare gases and carbon dioxide naturally present in the air that did not participate in combustion remain unchanged and are all discharged from the engine through the exhaust pipe. Because a small amount of unburned hydrogen is discharged from the engine, and a small amount of oxygen reacts with nitrogen at high temperatures to form nitrogen oxides, the intake air contains water vapor, affecting the amount of fresh air obtained. Therefore, the fresh air intake amount needs to be corrected to obtain a more accurate corrected fresh air intake amount.

[0080] For example, the exhaust hydrogen concentration is the hydrogen concentration in the exhaust gas, that is, the concentration of unburned hydrogen discharged from the engine. The exhaust hydrogen concentration can be obtained by installing a hydrogen concentration sensor in the exhaust pipe of the hydrogen fuel cell engine. The fresh air volume is corrected based on the exhaust hydrogen concentration, thereby improving the accuracy of the intake air volume acquisition.

[0081] S206. Obtain the unburned hydrogen corrected intake volume based on the exhaust hydrogen concentration, fresh intake volume, and hydrogen consumption.

[0082] The amount of air required for the combustion of unburned hydrogen, i.e., the corrected intake air volume for unburned hydrogen, can be obtained using the following formula:

[0083]

[0084] Wherein, G2 is the unburned hydrogen corrected intake air volume (kg / h), G1 is the fresh intake air volume (kg / h), H2 is the hydrogen consumption (kg / h), V3 is the exhaust hydrogen concentration, and M... A V1 represents the molecular weight of air (kg / mol) and the oxygen concentration in the air.

[0085] As an example, the fresh air intake rate G1 is 482 kg / h, the hydrogen consumption H2 is 7.92 kg / h, the exhaust hydrogen concentration V3 is 0.17%, the air oxygen concentration V1 is 21%, and the air molecular weight M is... A With a value of 0.029 kg / mol, the corrected intake flow rate of unburned hydrogen, G2, can be obtained as 2 kg / h.

[0086] S207, Obtain the concentration of nitrogen oxides in the exhaust gas.

[0087] The exhaust nitrogen oxide concentration is the concentration of nitrogen oxides in the exhaust gas. When hydrogen is burned, some oxygen reacts with nitrogen to produce nitrogen oxides. Figure 5 The graph shows the concentration relationship between the hydrogen-air mixture concentration and the nitrogen oxide concentration. (Refer to...) Figure 5When the concentration of hydrogen-air mixture is high, more nitrogen oxides are generated. The concentration of nitrogen oxides in exhaust gas can be obtained by installing a nitrogen oxide concentration sensor in the exhaust pipe of a hydrogen fuel cell engine.

[0088] S208. Obtain the nitrogen oxide-corrected intake volume based on the exhaust nitrogen oxide concentration, fresh intake volume, and hydrogen consumption.

[0089] The nitrogen oxides consist of over 90% nitrogen dioxide, with the remainder being nitric oxide. Nitric oxide is unstable and is ultimately converted entirely into nitrogen dioxide; therefore, all calculations are based on nitrogen dioxide. According to the chemical reaction formula for combustion, 1 mol of oxygen is required to produce 1 mol of nitrogen dioxide. Therefore, the molar amount of exhaust nitrogen dioxide can be obtained using the following formula:

[0090]

[0091] Where n is the molar amount of nitrogen dioxide (mol), G1 is the fresh intake air volume (kg / h), H2 is the hydrogen consumption (kg / h), V4 is the exhaust nitrogen oxide concentration (ppm), and M A The value represents the molecular weight of air (kg / mol).

[0092] The amount of air consumed in the reaction of nitrogen to produce nitrogen dioxide, i.e., the nitrogen oxide-corrected intake air volume, can be obtained using the following formula:

[0093]

[0094] Where G3 is the nitrogen oxide corrected intake air volume (kg / h), n is the nitrogen dioxide molar amount (mol), and M A V1 represents the molecular weight of air (kg / mol) and the oxygen concentration in the air.

[0095] Through transformation, we can obtain:

[0096]

[0097] As an example, the fresh air intake rate G1 is 482 kg / h, the hydrogen consumption H2 is 7.92 kg / h, the exhaust nitrogen oxide concentration V4 is 643 ppm, the air oxygen concentration V1 is 21%, and the air molecular weight M is... A With a value of 0.029 kg / mol, the nitrogen oxide corrected intake flow rate G3 can be obtained as 1.5 kg / h.

[0098] S209. Obtain the moisture content of dry air by referring to the table based on the ambient pressure, temperature, and relative humidity.

[0099] The dry air moisture content refers to the amount of water vapor contained in each kilogram of dry air. The dry air moisture content can be obtained by looking up a table based on the current environmental pressure, temperature, and relative humidity. The current environmental pressure, temperature, and relative humidity can be obtained by installing environmental sensors in the hydrogen fuel cell engine.

[0100] As an example, under an environment with an ambient pressure of 101.3 kPa, a temperature of 25°C, and a relative humidity of 50%, the moisture content of dry air is found to be 9.88 g / kg according to the table.

[0101] S210. Obtain the humidity-corrected intake volume based on the fresh intake volume and the moisture content of the dry air from the table.

[0102] The air entering the hydrogen fuel cell engine contains a small amount of water vapor, therefore the fresh air intake volume needs to be corrected based on the water vapor content to improve the accuracy of the intake volume. The humidity-corrected intake volume is related to both the fresh air intake volume and the moisture content of the dry air, and can be obtained using the following formula:

[0103] G4 = G1 * α;

[0104] Wherein, G4 is the humidity-corrected intake air volume (kg / h), G1 is the fresh intake air volume (kg / h), and α is the dry air moisture content (kg / h).

[0105] As an example, with a dry air moisture content α of 9.88 g / kg and a fresh air intake volume G1 of 482 kg / h, the humidity-corrected air intake volume G4 can be obtained as 4.8 kg / h.

[0106] S211. Based on the third parameter and the fresh air intake, obtain the corrected fresh air intake.

[0107] The corrected fresh air intake is a more accurate fresh air intake obtained by correcting the original fresh air intake. The third parameter includes at least one of the following: corrected unburned hydrogen intake, corrected nitrogen oxide intake, and corrected humidity intake. The corrected unburned hydrogen intake is the amount of air required for the combustion of unburned hydrogen; the corrected nitrogen oxide intake is the amount of air required for the reaction with nitrogen to produce nitrogen dioxide; and the corrected humidity intake is the water vapor content entering the hydrogen fuel cell engine. Therefore, the corrected fresh air intake can be obtained as follows:

[0108] G5 = G1 - G2 + G3 + G4;

[0109] Among them, G5 is the corrected fresh air intake volume (kg / h), G1 is the fresh air intake volume (kg / h), G2 is the corrected unburned hydrogen intake volume (kg / h), G3 is the corrected nitrogen oxide intake volume (kg / h), and G4 is the corrected humidity intake volume (kg / h).

[0110] As an example, with fresh air intake G1 being 482 kg / h, unburned hydrogen corrected air intake G2 being 2 kg / h, nitrogen oxides corrected air intake G3 being 1.5 kg / h, and humidity corrected air intake G4 being 4.8 kg / h, the corrected fresh air intake G5 can be obtained as 483.3 kg / h.

[0111] In other embodiments, when the hydrogen concentration sensor malfunctions, the unburned hydrogen correction intake volume is not obtained; the correction fresh intake volume can be obtained through nitrogen oxide correction intake volume and humidity correction intake volume. When the nitrogen oxide concentration sensor malfunctions, the nitrogen oxide correction intake volume is not obtained; the correction fresh intake volume can be obtained through unburned hydrogen correction intake volume and humidity correction intake volume. The correction fresh intake volume can also be obtained through other correction amounts, and this embodiment of the invention does not impose specific limitations on these aspects.

[0112] S212, Obtain the intake oxygen concentration.

[0113] The fourth parameter also includes the intake oxygen concentration. An intake oxygen sensor is installed in the intake manifold of the hydrogen fuel cell engine to measure the oxygen concentration after the exhaust gas is mixed with fresh air.

[0114] S213. Obtain the exhaust gas flow rate and EGR rate based on the fourth parameter.

[0115] In exhaust gas recirculation (EGR) technology, a portion of the exhaust gas from the engine is returned to the intake manifold and re-enters the cylinders along with fresh air, reducing the formation of nitrogen oxides (NOx). The exhaust gas flow rate is the amount of exhaust gas re-entering the cylinders, and the EGR rate is the ratio of the exhaust gas flow rate to the total amount of air intake into the cylinders. A fourth parameter includes the fresh air intake volume. Since hydrogen fuel cell engines do not emit carbon dioxide, the EGR rate cannot be calculated from the carbon dioxide concentration in the exhaust gas; instead, it is obtained from the fresh air intake volume. The exhaust gas flow rate can be obtained using the following formula:

[0116]

[0117] Where Q is the exhaust gas flow rate (kg / h), V5 is the intake oxygen concentration, G1 is the fresh intake air volume (kg / h), V1 is the air oxygen concentration, and V2 is the exhaust oxygen concentration.

[0118] EGR rate can be obtained using the following formula:

[0119]

[0120] Where η is the EGR rate, Q is the exhaust gas flow rate (kg / h), and G1 is the fresh air intake rate (kg / h).

[0121] As an example, with a fresh intake air volume G1 of 482 kg / h, an air oxygen concentration V1 of 21%, an exhaust oxygen concentration V2 of 8.94%, and an intake oxygen concentration V5 of 18.66%, the exhaust gas flow rate Q is 116.3 kg / h, and the EGR rate η is 0.194.

[0122] In other embodiments, the fresh intake volume is corrected to obtain the corrected fresh intake volume, so the exhaust gas flow rate and EGR rate can be obtained by correcting the fresh intake volume, resulting in more accurate exhaust gas flow rate and EGR rate.

[0123] S214. Obtain the total engine charge based on the fresh air intake, hydrogen consumption, and exhaust gas flow rate.

[0124] The total charge is the total amount of gas entering the cylinders of the hydrogen fuel cell engine. The total charge includes the air intake volume, exhaust gas flow rate, and hydrogen flow rate. The total charge can be obtained using the following formula:

[0125] N = G1 + Q + H2;

[0126] Where N is the total charge, Q is the exhaust gas flow rate (kg / h), G1 is the fresh air intake rate (kg / h), and H2 is the hydrogen consumption rate (kg / h).

[0127] As an example, with an exhaust gas flow rate Q of 116.3 kg / h, a fresh air intake rate G1 of 482 kg / h, and a hydrogen consumption rate H2 of 7.92 kg / h, the total charge N can be calculated to be 607.5 kg / h.

[0128] The intake air volume acquisition method for a hydrogen fuel cell engine provided in this invention obtains hydrogen consumption based on hydrogen injection volume, number of cylinders, engine speed, and working cycle revolutions. Fresh intake air volume is obtained based on hydrogen consumption and exhaust oxygen concentration. The fresh intake air volume is then corrected using unburned hydrogen, nitrogen oxide, and humidity-corrected intake air volumes to obtain a more accurate corrected fresh intake air volume. Exhaust gas flow rate and EGR rate are then obtained based on the fresh intake air volume. This intake air volume acquisition method, based on chemical equilibrium calculations, is unaffected by external environmental factors and engine operating conditions, improving versatility. It eliminates the need for flow meters to obtain exhaust gas efficiency and EGR rate, reducing throttling losses and costs. The method also provides high accuracy in obtaining the intake air volume, minimizing errors caused by heavy workloads.

[0129] Example 2

[0130] Figure 6 This is a schematic diagram of a hydrogen fuel cell engine system provided in an embodiment of the present invention, with reference to... Figure 6The hydrogen fuel cell engine system includes a hydrogen fuel cell engine and an engine control unit 1. The engine control unit 1 provided in this embodiment can execute the intake air quantity acquisition method for the hydrogen fuel cell engine provided in any embodiment of this invention, and has the corresponding functional modules and beneficial effects for executing the method; similarities can be found in the description above.

[0131] For example, the hydrogen fuel cell engine includes at least one of a plurality of sensors, including: an intake oxygen sensor 8, located in the intake manifold of the hydrogen fuel cell engine, for acquiring the intake oxygen concentration; an exhaust oxygen sensor 9, located in the exhaust manifold of the hydrogen fuel cell engine, for acquiring the exhaust oxygen concentration; a hydrogen concentration sensor 10, located in the exhaust manifold of the hydrogen fuel cell engine, for acquiring the exhaust hydrogen concentration; and a nitrogen oxide concentration sensor 12, located in the exhaust manifold of the hydrogen fuel cell engine, for acquiring the exhaust nitrogen oxide concentration. The hydrogen fuel cell engine also includes an environmental sensor 11 for detecting the current ambient pressure, temperature, and humidity of the hydrogen fuel cell engine's environment, facilitating the lookup of table data for dry air moisture content; and a speed sensor 7 for detecting the current engine speed, facilitating the calculation of the current hydrogen consumption of the engine. In the hydrogen fuel cell engine, air enters through the intake manifold, is cooled by the cooler, and then enters cylinder 4 through intake valve 17 after passing through throttle valve 16. At the same time, hydrogen is injected into the intake manifold through hydrogen nozzle 6. As the piston 5 moves, the gas in cylinder 4 heats up and pressurizes. After being ignited by spark plug 14, the hydrogen and fresh air burn in the cylinder, driving engine 15 to move. The exhaust gas after combustion enters the exhaust pipe through exhaust valve 18. Part of the exhaust gas is remixed with air through EGR valve 13 and enters the cylinder, while the rest is discharged through the exhaust pipe.

[0132] As an example, the hydrogen fuel engine provided in this embodiment of the invention can be an intake manifold hydrogen injection engine. In other embodiments, the hydrogen fuel engine provided in this embodiment of the invention can also be a cylinder direct injection hydrogen fuel engine. This embodiment of the invention does not impose any specific limitations on this.

[0133] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0134] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for obtaining the intake air volume of a hydrogen fuel cell engine, characterized in that, include: Obtain the hydrogen jet volume; The hydrogen consumption is obtained based on the first parameter; wherein the first parameter includes the hydrogen injection volume, number of cylinders, engine speed and working cycle revolutions, and the working cycle revolutions are the number of crankshaft rotations of the hydrogen fuel cell engine in one working cycle; The fresh air intake volume is obtained based on the second parameter; wherein the second parameter includes the hydrogen consumption and the oxygen concentration in the exhaust gas, and the fresh air intake volume is the total amount of gas entering the hydrogen fuel cell engine. The formula for calculating the fresh air intake volume is: ； Where G1 is the fresh air intake volume, in kg / h; H2 is the hydrogen consumption, in kg / h; M H M is the molecular weight of hydrogen, expressed in kg / mol. A V1 represents the molecular weight of air, expressed in kg / mol; V2 represents the oxygen concentration in the air and V1 represents the oxygen concentration in the exhaust gas.

2. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 1, characterized in that, Before obtaining the fresh intake air volume based on the second parameter, the following steps are also included: Obtain the oxygen concentration in the exhaust gas.

3. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 1, characterized in that, The number of cylinders refers to the number of cylinders in the hydrogen fuel cell engine.

4. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 1, characterized in that, After obtaining the fresh intake air volume based on the second parameter, the following is also included: Based on the third parameter and the fresh air intake, the corrected fresh air intake is obtained; The third parameter includes at least one of the following: unburned hydrogen corrected intake volume, nitrogen oxide corrected intake volume, and humidity corrected intake volume.

5. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 4, characterized in that, Before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes: Obtain the concentration of hydrogen in the exhaust gas; The unburned hydrogen corrected intake volume is obtained based on the exhaust hydrogen concentration, the fresh intake volume, and the hydrogen consumption.

6. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 4, characterized in that, Before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes: Obtain the concentration of nitrogen oxides in exhaust gas; The nitrogen oxide-corrected intake volume is obtained based on the exhaust nitrogen oxide concentration, the fresh intake volume, and the hydrogen consumption.

7. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 4, characterized in that, Before obtaining the corrected fresh air intake amount based on the third parameter and the fresh air intake amount, the method further includes: The moisture content of dry air can be obtained by referring to a table based on environmental pressure, temperature, and relative humidity. The humidity-corrected intake volume is obtained based on the fresh intake volume and the moisture content of the dry air obtained from the table.

8. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 1, characterized in that, After obtaining the fresh intake air volume based on the second parameter, the following is also included: Based on the fourth parameter, the exhaust gas flow rate and EGR rate are obtained; wherein, the EGR rate is the ratio of the exhaust gas flow rate to the total intake air volume of the intake cylinder, and the fourth parameter includes the fresh intake air volume.

9. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 8, characterized in that, The fourth parameter also includes the intake oxygen concentration; Before obtaining the exhaust gas flow rate and EGR rate based on the fourth parameter, the following steps are also included: Obtain the intake oxygen concentration.

10. The method for obtaining the intake air volume of a hydrogen fuel cell engine according to claim 8, characterized in that, After obtaining the exhaust gas flow rate and EGR rate based on the fresh intake air volume, the method further includes: The total engine charge is obtained based on the fresh air intake, hydrogen consumption, and exhaust gas flow rate.

11. A hydrogen fuel cell engine system, characterized in that, This includes a hydrogen fuel cell engine and an engine control unit; The engine control unit implements the method for obtaining the intake air volume of a hydrogen fuel cell engine as described in any one of claims 1-10.

12. The hydrogen fuel cell engine system according to claim 11, characterized in that, The hydrogen fuel cell engine includes at least one of a plurality of sensors, the plurality of sensors including: An intake oxygen sensor, located in the intake manifold of the hydrogen fuel cell engine, is used to obtain the intake oxygen concentration. An exhaust oxygen sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the concentration of oxygen in the exhaust gas. A hydrogen concentration sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the exhaust hydrogen concentration. A nitrogen oxide concentration sensor, located in the exhaust pipe of the hydrogen fuel cell engine, is used to obtain the concentration of nitrogen oxides in the exhaust gas.

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