Supercharging matching method for increasing supercharging benefit of single-cylinder hydrogen internal combustion engine

Abstract

The invention discloses a supercharging matching method for increasing the supercharging benefit of a single-cylinder hydrogen internal combustion engine, and belongs to the technical field of optimization of single-cylinder hydrogen internal combustion engines. The supercharging matching method for increasing the supercharging benefit of the single-cylinder hydrogen internal combustion engine comprises the following steps that the rotating speed or the air inlet channel length of the hydrogen internal combustion engine is calculated based on an internal combustion engine air inlet resonance relational expression; calculating intake air mass flow corresponding to the rotating speed of the hydrogen internal combustion engine according to the rotating speed and design power of the hydrogen internal combustion engine; according to the intake air mass flow and the pressurization system pressure ratio, the compressor working MAP is matched, and the compressor rotating speed is determined; and selecting a pressurization mode. According to the supercharging matching method for increasing the supercharging benefit of the single-cylinder hydrogen internal combustion engine, the air inlet resonance effect caused by the air inlet pulse of the single-cylinder hydrogen internal combustion engine is fully utilized, the air inlet loss caused by supercharging is reduced to the maximum extent, and the target of increasing the supercharging benefit of the single-cylinder hydrogen internal combustion engine is achieved; and the gas compressor always works at the optimal efficiency point, so that the higher system efficiency is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of single-cylinder hydrogen internal combustion engine optimization, and in particular to a supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine. Background Art

[0002] Hydrogen is a clean fuel with zero carbon emissions, making it an ideal "green" fuel. According to the reaction equation of hydrogen and air, theoretically, the air mass required to burn 1 kg of hydrogen is 34.32 kg, which is more than twice that of gasoline (14.8 kg) and twice that of natural gas (17.4 kg). Therefore, the demand for air volume in hydrogen internal combustion engines is much greater than that of gasoline and natural gas, and air intake supercharging is a very effective way to increase the air intake volume of internal combustion engines. Hydrogen internal combustion engines have an urgent need for air intake supercharging.

[0003] For multi-cylinder hydrogen internal combustion engines, the commonly used supercharging technology is exhaust gas turbocharging, and exhaust gas turbocharging technology has also developed to maturity. However, for single-cylinder hydrogen internal combustion engines, due to the unique working mode of gas, the intake stroke and exhaust stroke are not affected by other cylinders and are completely independent. Therefore, it is difficult to use exhaust gas turbocharging technology on single-cylinder hydrogen internal combustion engines. Therefore, naturally aspirated intake is more common in single-cylinder internal combustion engines.

[0004] For single-cylinder hydrogen internal combustion engines, it is urgent to change the naturally aspirated air into a supercharged intake to improve the power density. However, based on the existing single-cylinder engine industrial system, in order to control the development cost and shorten the development cycle, without redesigning the complex cylinder head intake duct, the intake supercharging leads to an increase in the intake flow and velocity, an increase in the intake resistance of the intake system, an increase in the pumping loss during the intake process, and a decrease in the benefits of supercharging, which is not conducive to improving the system efficiency. In order to increase the power output of a single-cylinder hydrogen internal combustion engine under the existing single-cylinder engine system, supercharging of a single-cylinder hydrogen internal combustion engine is imperative. At the same time, in order to reduce the intake loss caused by supercharging, a supercharging matching method that improves the supercharging benefits of a single-cylinder hydrogen internal combustion engine is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to provide a supercharging matching method for increasing the supercharging benefit of a single-cylinder hydrogen internal combustion engine, fully utilizing the intake resonance effect caused by the intake pulse of the single-cylinder hydrogen internal combustion engine, minimizing the intake loss caused by supercharging without changing the intake system of the prototype engine, and achieving the goal of enhancing the supercharging benefit of the single-cylinder hydrogen internal combustion engine; and making the compressor always work at the optimal efficiency point to ensure a higher system efficiency.

[0006] To achieve the above object, the present invention provides a supercharging matching method for increasing the supercharging benefit of a single-cylinder hydrogen internal combustion engine, comprising the following steps: S1. Calculate the speed or intake duct length of a hydrogen internal combustion engine based on the intake resonance relationship of the internal combustion engine.

[0007] Intake resonance is a prominent feature of single-cylinder engine intake. In order to reduce the intake loss during the supercharging process of a single-cylinder hydrogen internal combustion engine, the intake resonance should be fully utilized.

[0008] In one working cycle, the number of times the airflow in the intake duct resonates due to the intake pulse is calculated as: ; in, is the number of resonances of the airflow in the intake duct, For a single-cylinder hydrogen internal combustion engine working cycle, is the period of the resonance wave in the intake duct.

[0009] In the air intake duct, the air flow velocity can be considered as the local sound speed, and its calculation formula is: ; in, is the local sound speed in the inlet duct, that is, the air flow speed; is the adiabatic index, for air ; is the ideal gas constant for air J / (kg·K); is the intake air temperature, in K.

[0010] During the operation of a hydrogen internal combustion engine, the distance traveled by the pressure wave in the intake duct to complete one oscillation under the influence of the intake pulse is twice the length of the intake duct. When the intake pulse resonance wave propagates in the intake duct at the local sound speed, the calculation expression for the period of the resonance wave is: ;

[0011] in, is the intake duct length of a single-cylinder hydrogen internal combustion engine. The formula for calculating the resonant wave frequency is: ;

[0012] in, is the resonant wave frequency.

[0013] The calculation formula of the speed and working cycle of a four-stroke single-cylinder hydrogen internal combustion engine is: ;

[0014] in, is the operating speed of a single-cylinder hydrogen internal combustion engine, in r / min. The calculation formula for the intake frequency of a single-cylinder hydrogen internal combustion engine is: ;

[0015] in, is the intake frequency of a single-cylinder hydrogen internal combustion engine.

[0016] In one working cycle, the number of times the airflow in the intake duct resonates due to the intake pulse The calculation formula is: ;

[0017] The above formula determines the resonance number , Inlet duct length and hydrogen internal combustion engine speed The relationship between The value is a positive integer, that is ( is a positive integer), the intake resonance wave caused by the intake pulse of this cycle can maximize the intake volume of the next cycle.

[0018] When the hydrogen internal combustion engine is When there is no strict quantity requirement, if it is used as a range extender, the length of the intake duct of the hydrogen internal combustion engine prototype can be The working speed of the hydrogen internal combustion engine is determined by the relationship between the intake resonance and the intake resonance, so as to make full use of the intake resonance and increase the boost benefit. When there are strict quantity requirements, such as when used as a generator, it is limited by the power generation frequency requirements and has strict speed restrictions, then the working speed can be And the intake resonance relationship, calculate the intake duct length , the intake duct of the prototype engine is designed except for the cylinder head. This design is much easier than designing the intake runner inside the cylinder head, thereby making full use of the intake resonance and increasing the boost benefit.

[0019] S2. Calculate the intake air mass flow rate corresponding to the speed of the hydrogen internal combustion engine according to the speed and design power of the hydrogen internal combustion engine.

[0020] First, the calorific value of the mixed gas per unit time is calculated based on the design power and thermal efficiency of the hydrogen internal combustion engine. The specific calculation formula is: ;

[0021] in, is the calorific value of the mixed gas per unit time, P Design power for a single cylinder hydrogen internal combustion engine, Design thermal efficiency for hydrogen internal combustion engines.

[0022] According to the reaction equation of hydrogen-air mixture, the air mass flow rate corresponding to the calorific value per unit time is calculated. The reaction equation of hydrogen-air mixture is expressed as: ;

[0023] in, is the excess air coefficient during the operation of a single-cylinder hydrogen internal combustion engine. Therefore, the air mass flow rate is calculated as: ;

[0024] in, is the intake air mass flow rate during the operation of a single-cylinder hydrogen internal combustion engine; is the calorific value per unit mass of hydrogen, It is 120MJ / kg.

[0025] S3. According to the intake air mass flow rate and the pressure ratio of the supercharging system, the compressor operating MAP is matched and the compressor speed is determined.

[0026] Based on the calculated air mass flow, the air flow of the prototype engine in the naturally aspirated state at the current speed is input to calculate the boost ratio, and the calculation formula is: ;

[0027] in, is the required pressure ratio, It is the air mass flow rate of the prototype engine at the corresponding speed n under naturally aspirated state.

[0028] The compressor operating MAP is matched by the calculated intake air flow and compression ratio. The compressor operating MAP expression is: ;

[0029] in, is the compressor efficiency, is the compressor operating speed, is the air mass flow rate through the compressor, is the pressure ratio, is the mapping relationship between compressor working efficiency, air mass flow rate and compression ratio, is the mapping relationship between speed, air mass flow and compression ratio, is the intake air mass flow rate at the matching point.

[0030] With air flow and pressure ratio as input conditions, the matching principle is to make the point determined by the input air flow and pressure ratio appear in the area with the highest compressor efficiency, so that the corresponding compressor speed can be obtained. , the calculation formula is: .

[0031] S4. Select the boost mode.

[0032] After completing the boost MAP matching, the boost system can be designed according to different boost methods.

[0033] When the supercharging method is mechanical supercharging, the speed of the hydrogen internal combustion engine and the speed of the compressor are input to calculate the transmission speed ratio of the mechanical supercharging system. The calculation formula is: ;

[0034] in, is the transmission ratio of the supercharger transmission system, is the compressor speed, is the speed of the hydrogen internal combustion engine. Design a mechanical supercharger transmission system to achieve constant speed operation of the compressor so that it always operates at the highest efficiency point to ensure high system efficiency.

[0035] When electric supercharging is selected, the compressor speed is input to complete the design of the electric supercharging control subsystem, and the constant speed control of electric supercharging is realized, so that the compressor always works at the highest efficiency point to ensure higher system efficiency.

[0036] Complete supercharging matching to enhance the supercharging benefit of a single-cylinder hydrogen internal combustion engine.

[0037] The advantages and positive effects of the boost matching method for increasing the boost benefit of a single-cylinder hydrogen internal combustion engine described in the present invention are: on the one hand, the intake resonance effect caused by the intake pulse of the single-cylinder hydrogen internal combustion engine is fully utilized to minimize the intake loss caused by the boost, thereby achieving the goal of enhancing the boost benefit of the single-cylinder hydrogen internal combustion engine. On the other hand, the compressor is always operated at the optimal efficiency point to ensure a higher system efficiency.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is the overall flow chart of the present invention; Figure 2 It is a schematic diagram of the resonance of the intake pulse and the pressure wave in the intake passage of the single-cylinder hydrogen internal combustion engine of the present invention; Figure 3 This is a flow chart of calculating the speed of a hydrogen internal combustion engine in step S1 of the present invention; Figure 4 This is a flow chart of calculating the length of the intake duct in step S1 of the present invention; Figure 5 This is a flow chart of calculating the intake air mass flow rate in step S2 of the present invention; Figure 6 This is a flow chart of matching the compressor working MAP in step S3 of the present invention; Figure 7 This is a schematic diagram of boost matching in Embodiment 1 of the present invention; Figure 8 A flowchart of the selection of the boosting mode in step S4 of the present invention; Fig. 9 This is a schematic diagram of boost matching according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0040] In this application, 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: 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.

[0041] 2) Intake resonance: In the intake system, when air flows through the pipe, pressure waves are generated in the pipe due to the air flow speed and the geometric shape of the pipe. Due to the relationship between the pipe length of the intake system and the operating frequency (i.e., speed) of the engine, these pressure waves are reflected and superimposed, thus forming a "resonance" phenomenon.

[0042] 3) Completion of a resonance: In the intake duct, the process in which the pressure wave caused by the intake pulse propagates from the intake valve to the resonance cavity and then returns to the intake valve is defined as the completion of a resonance.

[0043] 4) Intake duct length: the distance the air flows between the valve and the pressure stabilizing chamber of a single-cylinder engine.

[0044] 5) Pressure stabilizing chamber: A space or environment where the air pressure remains constant during the intake process of a hydrogen internal combustion engine, generally a gas storage space that is relatively large relative to the cylinder displacement.

[0045] 6) Resonance relationship: An expression that determines the relationship between the resonance number, intake duct length and hydrogen internal combustion engine speed.

[0046] 7) Compression ratio: the ratio of compressor outlet pressure to inlet pressure.

[0047] 8) Compressor MAP: The compressor efficiency and speed contour diagram drawn with air flow as the horizontal axis and pressure ratio as the vertical axis can fully describe the working status and characteristics of the compressor.

[0048] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0049] Embodiment 1 like Figure 1 A supercharging matching method for increasing the supercharging benefit of a single-cylinder hydrogen internal combustion engine comprises the following steps: S1. Calculate the speed or intake duct length of a hydrogen internal combustion engine based on the intake resonance relationship of the internal combustion engine.

[0050] like Figure 2 In one working cycle, is the number of times the reflected wave resonates. It can be seen from the figure that only when the number of resonances is a positive integer, the intake resonance caused by the intake pulse of the previous cycle can play a maximum role in the next cycle intake and increase the intake volume. The relationship between the number of resonances, the length of the intake duct and the speed of the single-cylinder hydrogen internal combustion engine is determined as follows: ;

[0051] in, For a single-cylinder hydrogen internal combustion engine working cycle, is the period of the resonance wave in the intake duct, is the resonant wave frequency, is the intake frequency of a single-cylinder hydrogen internal combustion engine; is the local sound speed in the inlet duct, that is, the air flow speed; is the intake duct length of a single-cylinder hydrogen internal combustion engine, It is the operating speed of a single-cylinder hydrogen internal combustion engine.

[0052] like Figure 3 When a single-cylinder hydrogen internal combustion engine is used as a range extender, the following steps are included: S111: Input the intake conditions during the operation of a single-cylinder hydrogen internal combustion engine, including the intake temperature T , the ideal gas constant R (For air, J / (kg·K)) and adiabatic index , for air .

[0053] S112: Calculate the local sound speed in the intake duct, which is the air flow speed , the calculation formula is: .

[0054] S113: Input the intake resonance relationship, which is expressed as: .

[0055] S114: Input the resonance frequency , is a positive integer.

[0056] S115: Enter the intake duct length of a single-cylinder hydrogen internal combustion engine L .

[0057] S116: Get the speed of a single-cylinder hydrogen internal combustion engine .

[0058] like Figure 4 When a single-cylinder engine is used as a fixed-frequency generator, the following steps are included: S121: Input hydrogen internal combustion speed , this speed is determined by the frequency of fixed-frequency power generation demand.

[0059] S122: Input the intake resonance relationship, which is expressed as: .

[0060] S123: Input resonance frequency , is a positive integer.

[0061] S124: Input the intake conditions during the operation of the single-cylinder hydrogen internal combustion engine, including the intake temperature T , the ideal gas constant R (For air, J / (kg·K)) and adiabatic index .

[0062] S125: Calculate the local speed of sound in the intake duct using the following formula: .

[0063] S126: Get the length of the intake duct L , complete the intake duct length design.

[0064] S2. Calculate the intake air mass flow rate corresponding to the speed of the hydrogen internal combustion engine according to the speed and design power of the hydrogen internal combustion engine.

[0065] like Figure 5 After determining the operating speed of a single-cylinder hydrogen internal combustion engine, the specific calculation process of the intake air mass flow corresponding to the speed of the hydrogen internal combustion engine is as follows: S201: Input the design power of a single-cylinder hydrogen internal combustion engine P .

[0066] S202: Design efficiency of hydrogen-input internal combustion engines .

[0067] S203: Calculate the calorific value of the mixed gas per unit time, the calculation formula is: ;

[0068] in, is the calorific value of the mixed gas per unit time.

[0069] S204: Input the excess air coefficient of the designed hydrogen-air mixture .

[0070] S205: Calculate the intake air flow rate of the supercharged single-cylinder hydrogen internal combustion engine, using the following formula: ;

[0071] in, is the air mass flow rate during the operation of a single-cylinder hydrogen internal combustion engine, The lower calorific value per unit mass of hydrogen is 120MJ / kg.

[0072] S206: Input hydrogen internal combustion engine operating speed .

[0073] S207: Get the naturally aspirated prototype at a speed of Air mass flow rate .

[0074] S208: Calculate the pressure ratio of the boost system, and the calculation expression is: ;

[0075] in, is the required pressure ratio.

[0076] S3. According to the intake air mass flow rate and the pressure ratio of the supercharging system, the compressor operating MAP is matched and the compressor speed is determined.

[0077] like Figure 6 The specific process of matching the compressor operating MAP is as follows: S301: Determine the boost matching principle to match the intake air flow and boost ratio to the compressor's optimal thermal efficiency operating point.

[0078] S302: Input the intake air mass flow rate of a single-cylinder hydrogen internal combustion engine .

[0079] S303: Input boost system pressure ratio .

[0080] S304: Match the compressor MAP. The compressor MAP expression is: ;

[0081] in, is the compressor efficiency, is the compressor operating speed, is the flow rate through the compressor, is the pressure ratio, and They are the mapping relationships between compressor working efficiency and speed and flow rate and pressure ratio respectively.

[0082] The matching expression is: ;

[0083] S305: Calculate the compressor speed using the compressor MAP expression, expression: ;

[0084] in, is the compressor speed.

[0085] The boost matching diagram is as follows Figure 7 shown.

[0086] The main body of the schematic diagram is a MAP diagram of a general compressor, which includes normalized flow, pressure ratio, efficiency and speed data. The air mass flow and pressure ratio input by S302 and S303 are matched with the compressor efficiency. When the matched compressor efficiency is the maximum working efficiency point in the compressor MAP, it is considered that the compressor corresponding to the current compressor MAP is the required matching compressor, and its corresponding efficiency is Figure 7 The efficiency corresponding to the five-pointed star in the figure is used to implement S305 and determine the operating speed of the compressor. .

[0087] S4. Select the boost mode.

[0088] like Figure 8 The specific process of selecting the boosting method is as follows: S401: Select the supercharging method, including mechanical supercharging and electric supercharging.

[0089] S402: Mechanical supercharging is selected, and the implementation process includes steps of S403, S404, S405 and S406.

[0090] S403: Input the speed of the single-cylinder hydrogen internal combustion engine .

[0091] S404: Input compressor speed .

[0092] S405: Calculate the speed ratio of the supercharger transmission system using the following formula: ;

[0093] in, is the transmission ratio of the supercharger system.

[0094] S406: Design a mechanical supercharger transmission system based on the obtained transmission ratio to achieve constant speed control of the compressor.

[0095] S407: Selecting the boost mode as electric boost, the implementation process includes steps S408, S409 and S410.

[0096] S408: Input compressor speed .

[0097] S409: Electric boost power supply system design.

[0098] S410: Design of electric compressor speed control system to achieve constant speed control of the compressor.

[0099] During the implementation process, the intake resonance effect caused by the intake pulse of the single-cylinder hydrogen internal combustion engine was fully utilized. Under the condition of not changing the prototype's intake system to the maximum extent, the intake loss caused by the supercharging was minimized, the goal of enhancing the supercharging benefit of the single-cylinder hydrogen internal combustion engine was achieved, and a high system efficiency was ensured.

[0100] Embodiment 2 A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine comprises the following steps: S1. Calculate the speed or intake duct length of a hydrogen internal combustion engine based on the intake resonance relationship of the internal combustion engine.

[0101] like Figure 2 As shown. In one working cycle, 1,2,…, is the number of times the reflected wave resonates. It can be seen from the figure that only when the number of resonances is a positive integer, the intake resonance caused by the intake pulse of the previous cycle can play a maximum role in the next cycle intake and increase the intake volume. The relationship between the number of resonances, the length of the intake duct and the speed of the single-cylinder hydrogen internal combustion engine is determined as follows: ;

[0102] in, For a single-cylinder hydrogen internal combustion engine working cycle, is the period of the resonance wave in the intake duct, is the resonant wave frequency, is the intake frequency of a single-cylinder hydrogen internal combustion engine; is the local sound speed in the inlet duct, that is, the air flow speed; is the intake duct length of a single-cylinder hydrogen internal combustion engine, It is the operating speed of a single-cylinder hydrogen internal combustion engine.

[0103] like Figure 3 When a single-cylinder hydrogen internal combustion engine with an intake duct length of 0.3m and a displacement of 250cc is used as a motorcycle range extender, the following steps are included: S111: Input the intake conditions during the operation of a single-cylinder hydrogen internal combustion engine, including the intake temperatureT =300K, ideal gas constant R (For air, J / (kg·K)) and adiabatic index , for air .

[0104] S112: Calculate the local sound speed in the intake duct, which is the air flow speed u , the calculation formula is: 。

[0105] S113: Input the intake resonance relationship, which is expressed as: ;

[0106] S114: Input the resonance frequency .

[0107] S115: Enter the intake duct length of a single-cylinder hydrogen internal combustion engine L =0.3m.

[0108] S116: Get the speed of a single-cylinder hydrogen internal combustion engine That is, when the supercharged single-cylinder hydrogen internal combustion engine is used as a motorcycle range extender, its speed should be designed to operate at a fixed speed of 6944r / min to increase the supercharging benefit.

[0109] like Figure 4 When a single-cylinder hydrogen internal combustion engine with a displacement of 250cc is used as a fixed-frequency generator and the speed requirement of the hydrogen internal combustion engine is 6000r / min, the following steps are included: S121: Input hydrogen internal combustion speed .

[0110] S122: Input the intake resonance relationship, which is expressed as: .

[0111] S123: Input resonance frequency .

[0112] S124: Input the intake conditions during the operation of the single-cylinder hydrogen internal combustion engine, including the intake temperature T =300K, ideal gas constant R (For air, J / (kg·K)) and adiabatic index (For air .

[0113] S125: Calculate the local speed of sound in the intake duct using the following formula: .

[0114] S126: Get the length of the intake duct L =0.347m, completing the design of the air intake duct length.

[0115] Taking the use of a single-cylinder hydrogen internal combustion engine as a fixed-frequency generator as an example, the boost matching process is implemented. It should be understood that when a single-cylinder hydrogen internal combustion engine is used as a range extender, except for the different calculated values, the other implementation processes are the same.

[0116] S2. Calculate the intake air mass flow rate corresponding to the speed of the hydrogen internal combustion engine according to the speed and design power of the hydrogen internal combustion engine.

[0117] The supercharged single-cylinder hydrogen internal combustion engine has a design power of 15kW, a design thermal efficiency of 32%, and a design excess air coefficient of 2 to achieve lower NOx emissions.

[0118] like Figure 5 After determining the operating speed of a single-cylinder hydrogen internal combustion engine, the specific calculation process of the intake air mass flow corresponding to the speed of the hydrogen internal combustion engine is as follows: S201: Input the design power of a single-cylinder hydrogen internal combustion engine P =15kW.

[0119] S202: Design efficiency of hydrogen-input internal combustion engines .

[0120] S203: Calculate the calorific value of the mixed gas per unit time, the calculation formula is: ;

[0121] in, is the calorific value of the mixed gas per unit time.

[0122] S204: Input the excess air coefficient of the designed hydrogen-air mixture .

[0123] S205: Calculate the intake air flow rate of the supercharged single-cylinder hydrogen internal combustion engine, using the following formula: ;

[0124] in, is the air mass flow rate during the operation of a single-cylinder hydrogen internal combustion engine, The lower calorific value per unit mass of hydrogen is 120MJ / kg.

[0125] S206: Input hydrogen internal combustion engine operating speed .

[0126] S207: Get the naturally aspirated prototype at a speed of Air mass flow rate .

[0127] S208: Calculate the pressure ratio of the boost system, and the calculation expression is: ;

[0128] in, is the required pressure ratio.

[0129] S3. According to the intake air mass flow rate and the pressure ratio of the supercharging system, the compressor operating MAP is matched and the compressor speed is determined.

[0130] like Figure 6 The specific process of matching the compressor operating MAP is as follows: S301: Determine the boost matching principle to match the intake air flow and boost ratio to the compressor's optimal thermal efficiency operating point.

[0131] S302: Input the intake air mass flow rate of a single-cylinder hydrogen internal combustion engine .

[0132] S303: Input boost system pressure ratio .

[0133] S304: Match the compressor MAP. The compressor MAP expression is: ;

[0134] in, is the compressor efficiency, is the compressor operating speed, is the flow rate through the compressor, is the pressure ratio, and They are the mapping relationships between compressor working efficiency and speed and flow rate and pressure ratio respectively.

[0135] The matching expression is: ;

[0136] S305: Calculate the compressor speed from the compressor MAP expression, the expression is: ;

[0137] in, is the compressor speed.

[0138] The boost matching diagram is as follows Fig. 9 shown.

[0139] The main body of the schematic diagram is a MAP diagram of a general compressor, which includes the flow rate, pressure ratio, efficiency and speed data of the compressor. The air mass flow rate and pressure ratio input by S302 and S303 are matched with the compressor efficiency. When the matched compressor efficiency is the maximum working efficiency point in the compressor MAP, it is considered that the compressor corresponding to the current compressor MAP is the compressor to be matched, and its corresponding efficiency is Fig. 9 The efficiency corresponding to the five-pointed star in the figure is used to implement S305 and determine the operating speed of the compressor. .

[0140] S4. Select the boost mode.

[0141] like Figure 8 The specific process of selecting the boost mode is as follows: S401: Select the supercharging method, including mechanical supercharging and electric supercharging.

[0142] S402: Mechanical supercharging is selected, and the implementation process includes steps of S403, S404, S405 and S406.

[0143] S403: Input the speed of the single-cylinder hydrogen internal combustion engine .

[0144] S404: Input compressor speed .

[0145] S405: Calculate the speed ratio of the supercharger transmission system using the following formula: ;

[0146] in, is the transmission ratio of the supercharger system.

[0147] S406: Design a mechanical supercharger transmission system based on the obtained transmission ratio to achieve constant speed control of the compressor.

[0148] S407: Selecting the boost mode as electric boost, the implementation process includes steps S408, S409 and S410.

[0149] S408: Input compressor speed .

[0150] S409: Electric boost power supply system design.

[0151] S410: Design of electric compressor speed control system to achieve constant speed control of the compressor.

[0152] During the implementation process, the intake resonance effect caused by the intake pulse of the single-cylinder hydrogen internal combustion engine was fully utilized. Under the condition of not changing the prototype's intake system to the maximum extent, the intake loss caused by the supercharging was minimized, the goal of enhancing the supercharging benefit of the single-cylinder hydrogen internal combustion engine was achieved, and a high system efficiency was ensured.

[0153] Therefore, the boost matching method for increasing the boost benefit of a single-cylinder hydrogen internal combustion engine described in the present invention is adopted to fully utilize the intake resonance effect caused by the intake pulse of the single-cylinder hydrogen internal combustion engine, minimize the intake loss caused by the boost, and achieve the goal of enhancing the boost benefit of the single-cylinder hydrogen internal combustion engine; and make the compressor always work at the optimal efficiency point to ensure a higher system efficiency.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine, characterized in that: The following steps are involved: S1. Calculate the speed or intake duct length of the hydrogen internal combustion engine based on the internal combustion engine intake resonance relationship; S2. Calculate the intake air mass flow rate corresponding to the speed of the hydrogen internal combustion engine according to the speed and design power of the hydrogen internal combustion engine; S3, matching the compressor working MAP according to the intake air mass flow rate and the pressure ratio of the supercharging system, and determining the compressor speed; S4. Select the boost mode.

2. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 1, characterized in that: In S1, the intake resonance relationship between the intake resonance number, the intake duct length and the speed of the hydrogen internal combustion engine is: ； in, is the intake resonance number, is the adiabatic index, is the ideal gas constant, is the intake air temperature, is the inlet duct length, is the speed of the hydrogen internal combustion engine; The intake resonance caused by the intake pulse of the hydrogen internal combustion engine is used to reduce the intake resistance caused by the boost.

3. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 2, characterized in that: Said , Is a positive integer.

4. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 3, characterized in that: When a hydrogen internal combustion engine is used as a range extender, the speed of the hydrogen internal combustion engine is calculated according to the intake duct length using the intake resonance relationship.

5. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 4, characterized in that: When the hydrogen internal combustion engine is used as a fixed-frequency generator, the intake duct length is calculated using the intake resonance relationship according to the hydrogen internal combustion engine speed required by the power generation frequency.

6. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 5, characterized in that: In S2, the intake air mass flow rate calculation expression is: ； in, is the intake air mass flow rate during the operation of a single-cylinder hydrogen internal combustion engine; is the calorific value of the mixed gas per unit time, is the calorific value per unit mass of hydrogen, is the excess air coefficient of the hydrogen-air mixture reaction.

7. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 6, characterized in that: In S3, the compressor operating MAP is matched according to the best efficiency point matching principle. The mathematical expression of the best efficiency point matching principle is: ; in, is the compressor efficiency, is the compressor operating speed, is the air mass flow rate through the compressor, is the pressure ratio, is the mapping relationship between compressor working efficiency, air mass flow rate and compression ratio, is the mapping relationship between speed, air mass flow and compression ratio, f is the intake air mass flow rate at the matching point, is the pressure increase ratio at the matching point.

8. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 7, characterized in that: In S3, the calculation expression of the pressure ratio of the supercharging system is: ； in, is the pressure ratio, It is the air mass flow rate of the prototype engine under naturally aspirated state.

9. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 8, characterized in that: In S4, when mechanical supercharging is selected, the transmission ratio calculation formula of the supercharging transmission system is: ； in, is the transmission ratio of the supercharger transmission system, is the compressor speed, is the speed of the hydrogen internal combustion engine.

10. A supercharging matching method for increasing supercharging benefit of a single-cylinder hydrogen internal combustion engine according to claim 9, characterized in that: In S4, when electric supercharging is selected, the compressor speed is Design an electric boost control system to achieve constant speed control of the electric boost compressor.

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