A lean-burn hydrogen engine system and control method thereof

Abstract

The present application relates to a lean-burn hydrogen engine system and a control method thereof, wherein two intake pipes are connected in parallel between an outlet of an electric compressor and an inlet of an intercooler, and the intercooler is connected to the inlet of the hydrogen engine; the intake pipe comprises a flow valve and a mechanical compressor connected in sequence; two exhaust gas boost pipes are connected in parallel to a vehicle aftertreatment system, and are both connected to an exhaust gas recirculation pipe connected to the inlet of the hydrogen engine, and a high-pressure EGR valve is provided on the exhaust gas recirculation pipe; a vehicle ECU is connected to the electric compressor, the flow valve and the high-pressure EGR valve signal; the electric compressor replenishes the intake volume of the two intake pipes to meet the air-fuel ratio requirement of the hydrogen engine, and the combustion state in the cylinder of the hydrogen engine is adjusted by setting up two exhaust gas boost pipes and exhaust gas recirculation technology, in combination with the electric compressor and the flow valve, to avoid abnormal combustion problems that frequently occur under medium and high loads, taking into account both high and low speeds, and also having the effect of reducing the requirement for installation space.

Description

Technical Field

[0001] The present application relates to the technical field of low-carbon fuel hydrogen engines, and in particular to a lean-burn hydrogen engine system and a control method thereof. Background Art

[0002] As a zero-carbon fuel, hydrogen is one of the alternative fuels with great potential to replace traditional fossil fuels. Hydrogen internal combustion engines are divided into two types according to the fuel injection method: port injection (PFI) and direct injection (DI). The main advantage of using hydrogen as a fuel for internal combustion engines is that it does not produce carbon emissions, so no emissions such as carbon monoxide, hydrocarbons and carbon dioxide are formed during the combustion of air and hydrogen. However, since there is also oxygen and nitrogen in the air, the main exhaust gas emissions are NOx. The premixed hydrogen combustion in the cylinder of a hydrogen engine can be divided into chemical equivalent combustion and lean combustion. The difference lies in the difference in excess air coefficient. Lean combustion requires more air supply, and the lean combustion process can effectively reduce NOx emissions.

[0003] Hydrogen has unique physical and chemical properties such as high energy density, wide ignition limit, low ignition energy, and fast combustion speed, which improve the thermal efficiency and operating stability of hydrogen engines. However, high combustion efficiency will lead to excessive pressure and temperature in the cylinder, increase NO emissions, and promote the occurrence of abnormal combustion such as knock and pre-ignition. The frequent occurrence of abnormal combustion problems under medium and high loads and the solution to the contradiction between higher power output and NO emissions are the main bottlenecks restricting the development of hydrogen engines. Based on this, exhaust gas recirculation (EGR) technology is used to adjust the combustion state in the cylinder of hydrogen engines and reduce combustion instability.

[0004] The working principle of the turbocharger system is to use the exhaust energy of the hydrogen engine to drive the turbine of the supercharger to rotate, thereby driving the compressor to rotate to pressurize the air. However, when the hydrogen engine uses hydrogen fuel, its characteristics are conducive to improving combustion efficiency, but it is not conducive to the supercharging system. In the case of equivalent combustion, it can achieve full combustion at a faster speed. Rapid combustion will produce a more ideal isochoric process, so that the heat energy generated by the combustion of the fuel can be fully converted into mechanical energy, thereby effectively improving the thermal efficiency of the whole machine, but at the same time it also reduces the energy in the exhaust gas. In the case of lean combustion, the exhaust energy will be lower, which will directly affect the power of the hydrogen engine, so the matching of the supercharging system is more difficult.

[0005] The turbocharger system of the existing traditional fuel hydrogen engine, the more common turbochargers are mainly FGT (Fixed Gate Turbocharger) fixed cross-section turbocharger, WGT (Waste Gate Turbocharger) wastegate valve turbocharger and VGT (Variable Geometry Turbocharger) variable cross-section turbocharger, and there are also two-stage series turbochargers, that is, turbochargers based on the above three types of turbochargers in series combination. The structure of the turbocharger determines that it is impossible to take into account both low-speed and high-speed conditions at the same time. In order to improve the low-speed performance of the hydrogen engine, the WGT wastegate valve turbocharger must use a smaller volute to improve the air-fuel ratio of the low-speed condition. Therefore, in order to avoid supercharger overspeed and hydrogen engine explosion pressure exceeding the limit, it is necessary to open the bypass valve for venting at high speed. The low-speed performance of the VGT variable cross-section turbocharger is slightly better than that of the WGT, but in order to match the low-speed and high-speed conditions at the same time, a compromise needs to be considered when selecting. In addition, the VGT has a high cost and poor reliability. Summary of the invention

[0006] The embodiment of the present application provides a lean-burn hydrogen engine system and a control method thereof to solve the problem in the related art that it is difficult to balance high speed and low speed in either a single-stage supercharging or a two-stage series supercharging hydrogen engine.

[0007] In a first aspect, a lean-burn hydrogen engine system is provided, comprising:

[0008] Two air intake pipelines are connected in parallel between the air outlet of the electric compressor and the air inlet of the intercooler, and the intercooler is connected to the air inlet of the hydrogen engine; the air intake pipeline includes a flow valve and a mechanical compressor connected in sequence;

[0009] Two exhaust gas boosting pipelines, one of which is connected to the exhaust port of a part of the cylinder body of the hydrogen engine, and the other is connected to the exhaust port of another part of the cylinder body of the hydrogen engine; both exhaust gas boosting pipelines are connected in parallel with the vehicle after-treatment system, and are connected to the exhaust gas recirculation pipeline connected to the air inlet of the hydrogen engine, and the exhaust gas recirculation pipeline is provided with a high-pressure EGR valve;

[0010] The vehicle ECU is connected to the electric compressor, the flow valve and the high-pressure EGR valve signal.

[0011] In some embodiments, the exhaust gas boost pipeline includes a hydrogen engine exhaust manifold, the hydrogen engine exhaust manifold is connected to a turbine via a bypass valve, the turbine is connected to the vehicle aftertreatment system via an exhaust pipe, and the exhaust pipe is also connected to the exhaust gas recirculation pipeline;

[0012] The turbine and the mechanical compressor are mechanically connected.

[0013] In some embodiments, the exhaust gas recirculation pipeline includes a high-pressure EGR pipe, the high-pressure EGR pipe is connected to an EGR cooler, and the EGR cooler is connected to the air intake of the hydrogen engine;

[0014] The high-pressure EGR valve is arranged on the high-pressure EGR pipe.

[0015] In some embodiments, a drive motor is further included which is connected to the output end of the hydrogen engine via a clutch; the clutch and the drive motor are signal-connected to the vehicle ECU.

[0016] In some embodiments, one of the two air intake pipes is connected to an air intake port of a portion of a cylinder block of the hydrogen engine through an intercooler, and the other air intake pipe is connected to an air intake port of another portion of a cylinder block of the hydrogen engine.

[0017] In a second aspect, a control method for a lean-burn hydrogen engine system is provided, comprising:

[0018] Determine the actual air-fuel ratio of the hydrogen engine in the current working condition and the designed air-fuel ratio of the current working condition to determine whether the engine is in a state of insufficient intake and hydrogen cannot burn stably;

[0019] If yes, adjust the speed of the electric compressor to increase the air intake;

[0020] Otherwise, the intake uniformity coefficient is obtained, and the flow valve and the high-pressure EGR valve are controlled according to the design rules.

[0021] In some embodiments, controlling the flow valve and the high pressure EGR valve according to the design rules includes the following steps:

[0022] Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition;

[0023] If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves in the two intake pipes are fully opened;

[0024] If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves and the opening of the high-pressure EGR valve are adjusted to ensure that the hydrogen engine is in a state of uniform intake and stable combustion.

[0025] In a third aspect, a control method for a lean-burn hydrogen engine system is provided, comprising:

[0026] The lean-burn hydrogen engine system further includes a drive motor connected to the output end of the hydrogen engine via a clutch; the clutch and the drive motor are signal-connected to the vehicle ECU;

[0027] Determine the actual air-fuel ratio of the hydrogen engine in the current working condition and the designed air-fuel ratio of the current working condition to determine whether the engine is in a state of insufficient intake and hydrogen cannot burn stably;

[0028] If so, the bypass valves of the two exhaust gas boost lines are opened, and the power source is switched from the hydrogen engine to the drive motor through the clutch;

[0029] Otherwise, the intake uniformity coefficient is obtained, and the flow valve and the high-pressure EGR valve are controlled according to the design rules.

[0030] In some embodiments, controlling the flow valve and the high pressure EGR valve according to the design rules includes the following steps:

[0031] Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition;

[0032] If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves in the two intake pipes are fully opened;

[0033] If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves and the high-pressure EGR valve are adjusted, as well as the speed of the electric compressor, so that the hydrogen engine is in a state of uniform intake and stable combustion.

[0034] In a fourth aspect, a vehicle is provided, which includes the above lean-burn hydrogen engine system.

[0035] The beneficial effects of the technical solution provided by this application include:

[0036] The embodiment of the present application provides a lean-burn hydrogen engine system and a control method thereof. Since the electric compressor can replenish the intake volume of two intake pipes to meet the air-fuel ratio requirement of the hydrogen engine, and through the arrangement of two exhaust gas boost pipes, under the unique physical and chemical properties of hydrogen such as high energy density, wide ignition limit, low ignition energy, and fast combustion speed, exhaust gas recirculation (EGR) technology is adopted, combined with an electric compressor and a flow valve to adjust the combustion state in the cylinder of the hydrogen engine, avoid abnormal combustion problems that frequently occur under medium and high loads, and solve the contradiction between higher power output and NO emissions; thus, the parallel mode of this method takes into account both high speed and low speed, and also has the effect of reducing the requirements for installation space.

[0037] Furthermore, the present application can be used not only in pure hydrogen mode, but also in hybrid mode. In hybrid mode, the low speed is directly driven by the drive motor, and the medium and high speed conditions are adjusted by the electric compressor for intake uniformity and combustion stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 The air-fuel ratio comparison diagram of single-stage supercharging and two-stage supercharging provided in the related technology;

[0040] Figure 2 A comparison diagram of excess air coefficients between single-stage supercharging and two-stage supercharging provided in the related art;

[0041] Figure 3 A schematic diagram of the structure of a lean-burn hydrogen engine system with a drive motor provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of a lean-burn hydrogen engine system without a drive motor provided in an embodiment of the present application;

[0043] Figure 5 A schematic diagram of a hybrid mode control strategy provided in an embodiment of the present application;

[0044] Figure 6 A schematic diagram of the control strategy for the operation of a pure hydrogen engine provided in an embodiment of the present application.

[0045] In the figure: 1. Intake pipe; 100. Flow valve; 101. Mechanical compressor; 2. Electric compressor; 3. Intercooler; 4. High-pressure EGR valve; 5. Vehicle ECU; 6. Turbine; 7. Exhaust pipe; 8. High-pressure EGR pipe; 9. EGR cooler; 10. Drive motor; 11. Hydrogen engine exhaust manifold. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0047] A lean-burn hydrogen engine system and a control method thereof are provided to solve the problem in the related art that high speed and low speed are not easy to be balanced regardless of whether it is a single-stage supercharging or a two-stage series supercharging hydrogen engine.

[0048] What should be understood from the above is:

[0049] For hydrogen engines, the excess air ratio is less than 1.8, and the hydrogen-air mixture is prone to detonation. The excess air ratio between 1.8 and 2.4 can provide the best brake thermal efficiency and stable operation. For the lowest NOx emissions, the excess air ratio must be increased to above 2.4. When the excess air ratio is greater than 2.7, the combustion speed slows down significantly, reducing efficiency and increasing the instability trend.

[0050] Based on a 13L hydrogen engine, a simulation analysis of the hydrogen engine supercharging system technology route found that no matter it is a single-stage supercharging or a two-stage supercharging hydrogen engine, there is a problem of not being able to balance high speed and low speed, which will cause the engine to have insufficient low-speed torque or insufficient high-speed horsepower. Figure 1 and Figure 2 , we can see the above problems.

[0051] See also Figure 3-Figure 6 , a lean-burn hydrogen engine system, characterized in that it comprises:

[0052] Two air intake pipelines 1 are connected in parallel between the air outlet of the electric compressor 2 and the air inlet of the intercooler 3, and the intercooler 3 is connected to the air inlet of the hydrogen engine; the air intake pipeline 1 includes a flow valve 100 and a mechanical compressor 101 connected in sequence;

[0053] Two exhaust gas boosting pipelines, one of which is connected to the exhaust port of a part of the cylinder body of the hydrogen engine, and the other exhaust gas boosting pipeline is connected to the exhaust port of another part of the cylinder body of the hydrogen engine; both exhaust gas boosting pipelines are connected in parallel with the vehicle after-treatment system, and are connected to an exhaust gas recirculation pipeline connected to the air inlet of the hydrogen engine, and a high-pressure EGR valve 4 is provided on the exhaust gas recirculation pipeline;

[0054] The vehicle ECU 5 is connected to the electric compressor 2, the flow valve 100 and the high-pressure EGR valve 4 by signals. The electric compressor 2 is connected to the outside atmosphere.

[0055] The electric compressor 2 can replenish the intake volume of the two intake pipes 1 to meet the air-fuel ratio requirements of the hydrogen engine, and through the arrangement of two exhaust gas boost pipes, under the unique physical and chemical properties of hydrogen such as high energy density, wide ignition limit, low ignition energy, and fast combustion speed, the exhaust gas recirculation EGR technology is adopted, combined with the electric compressor 2 and the flow valve 100 to adjust the combustion state in the cylinder of the hydrogen engine, avoid the abnormal combustion problem that frequently occurs under medium and high loads, and solve the contradiction between higher power output and NO emissions; thus, the parallel mode of this method takes into account both high speed and low speed, and also has the effect of reducing the requirements for installation space.

[0056] Furthermore, the present application can be used not only in pure hydrogen mode but also in hybrid mode. In hybrid mode, low speed is directly driven by the drive motor 10, while medium and high speed conditions are driven by the electric compressor 2 to adjust the intake uniformity and combustion stability.

[0057] In some preferred embodiments, the exhaust gas boost pipeline includes a hydrogen engine exhaust manifold 11, which is connected to a turbine 6 through a bypass valve, and the turbine 6 is connected to the vehicle post-treatment system through an exhaust pipe 7, and the exhaust pipe 7 is also connected to the exhaust gas recirculation pipeline; the turbine 6 is mechanically connected to the mechanical compressor 101. The exhaust gas recirculation pipeline includes a high-pressure EGR pipe 8, which is connected to an EGR cooler 9, and the EGR cooler 9 is connected to the hydrogen engine air intake; the high-pressure EGR valve 4 is arranged on the high-pressure EGR pipe 8.

[0058] Of the two air intake pipes 1, one air intake pipe 1 is connected to an air intake port of a part of the cylinder body of the hydrogen engine through an intercooler 3, and the other air intake pipe 1 is connected to an air intake port of another part of the cylinder body of the hydrogen engine.

[0059] Specifically, it can be: a supercharging system with an electric compressor 2 and two single-stage superchargers working simultaneously is formed by a mechanical compressor 101 and a turbine 6, and the exhaust manifold is a group of three cylinders, and the two groups of exhaust manifolds are respectively connected to a supercharging system of a single-stage supercharger. The electric compressor 2 is connected to the two single-stage superchargers through a flow valve 100, which is different from the traditional two-stage superchargers in series and the single-stage supercharger. When used as a hybrid hydrogen fuel engine system, the drive motor 10 is connected to the engine through a clutch. Through the control strategy, not only can the pure electric drive vehicle driving mechanism be realized, but also the intake uniformity and combustion stability of the hydrogen engine can be achieved by adjusting the flow valve.

[0060] refer to Figure 6 , the control strategy of this application for pure hydrogen engine is:

[0061] A control method for a lean-burn hydrogen engine system comprises the following steps:

[0062] Step 100, judging the actual air-fuel ratio of the current working condition of the hydrogen engine and the designed air-fuel ratio of the current working condition to judge whether the hydrogen is in a state of insufficient intake and unable to stably burn;

[0063] Step 101: If yes, adjust the speed of the electric compressor 2 to increase the air intake;

[0064] Step 102: Otherwise, obtain the intake uniformity coefficient, and control the flow valve 100 and the high-pressure EGR valve 4 according to the design rules.

[0065] The specific steps in step 102 are:

[0066] Controlling the flow valve 100 and the high-pressure EGR valve 4 according to the design rules includes the following steps:

[0067] Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition;

[0068] If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves 100 in the two intake pipes 1 are fully opened;

[0069] If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves 100 and the opening of the high-pressure EGR valve 4 are adjusted to ensure that the hydrogen engine is in a uniform intake and stable combustion state.

[0070] The vehicle ECU5 obtains signals from the accelerator pedal position sensor, engine speed sensor, intake flow valve sensor, and fuel quantity sensor in real time to determine whether the engine air-fuel ratio meets the design air-fuel ratio requirements. If the actual air-fuel ratio does not meet the design requirements, it means that under certain operating conditions, the hydrogen engine of the vehicle cannot burn stably due to insufficient gas volume. At this time, the vehicle ECU controls the speed of the E-boost motor of the electric compressor to assist in increasing the intake volume. If the actual air-fuel ratio meets the design requirements, the vehicle enters the hydrogen engine operation mode, and the intake volume signal is obtained at the same time and converted into an intake uniformity coefficient. If the intake uniformity coefficient meets the design requirements, the E1 and E2 flow valves (flow valve 100) are fully opened. If the intake uniformity coefficient does not meet the design requirements, the opening of the flow valves E1 and E2 and the opening of the EGR valves S1 and S2 (high-pressure EGR valve 4) are adjusted to ensure that the hydrogen engine is in a state of uniform intake and efficient and stable combustion.

[0071] refer to Figure 5 The hybrid control strategy for the hybrid arrangement of the hydrogen engine and the drive motor 10 in this application is:

[0072] The lean-burn hydrogen engine system further includes a drive motor 10 connected to the output end of the hydrogen engine via a clutch; the clutch and the drive motor 10 are signal-connected to the vehicle ECU 5;

[0073] A control method for a lean-burn hydrogen engine system comprises the following steps:

[0074] Step 100, judging the actual air-fuel ratio of the current working condition of the hydrogen engine and the designed air-fuel ratio of the current working condition to judge whether the hydrogen is in a state of insufficient intake and unable to stably burn;

[0075] Step 103: If yes, open the bypass valves of the two exhaust gas boost pipes, and switch the power source from the hydrogen engine to the drive motor 10 through the clutch;

[0076] Step 104 , otherwise, obtain the intake uniformity coefficient, and control the flow valve 100 and the high-pressure EGR valve 4 according to the design rules.

[0077] In step 104, the flow valve 100 and the high-pressure EGR valve 4 are controlled according to the design rules, including the following steps:

[0078] Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition;

[0079] If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves 100 in the two intake pipes 1 are fully opened;

[0080] If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves 100 and the high-pressure EGR valve 4 are adjusted, as well as the speed of the electric compressor 2, so that the hydrogen engine is in a state of uniform intake and stable combustion.

[0081] The above can be understood as:

[0082] According to the matching requirements of the hydrogen engine in various working conditions and the design requirements of the air-fuel ratio, the vehicle ECU5 obtains the signals from the accelerator pedal position sensor, the engine speed sensor, the intake flow valve sensor, and the oil quantity sensor in real time to determine whether the engine air-fuel ratio meets the design air-fuel ratio requirements. If the actual air-fuel ratio does not meet the design requirements, it means that under certain working conditions, the hydrogen engine of the vehicle cannot burn stably due to insufficient gas volume. At this time, the motor drive mode is switched to drive the vehicle by the motor. If the actual air-fuel ratio meets the design requirements, the vehicle enters the hydrogen engine operation mode, and the intake volume signal is obtained at the same time and converted into the intake uniformity coefficient. If the intake uniformity coefficient meets the design requirements, the E1 and E2 flow valves (flow valve 100) are fully opened. If the intake uniformity coefficient does not meet the design requirements, the opening of the flow valves E1 and E2, the opening of the EGR valves S1 and S2 (high-pressure EGR valve 4) and the motor speed of the electric compressor 2 are adjusted to make the hydrogen engine in a state of uniform intake and efficient and stable combustion.

[0083] A vehicle, characterized in that it comprises the lean-burn hydrogen engine system according to any one of claims 1-5.

[0084] Through the above description, the problem of insufficient exhaust energy of hydrogen engine lean-burn combustion is solved. The problem that traditional turbocharging system is difficult to take into account both high-speed power and low-speed torque requirements at the same time is solved. In pure engine working mode, the intake volume of two parallel single-stage superchargers can be supplemented by the electric compressor to meet the air-fuel ratio requirements of the engine. In hybrid mode, low speed is directly driven by the motor, and medium and high speed conditions are adjusted by the electric compressor for intake uniformity and combustion stability.

[0085] The hybrid mode solves the problem of slow transient response of the engine through the electric motor, while the pure engine mode solves the problem of slow transient response through the electric compressor.

[0086] Hydrogen has unique physical and chemical properties such as high energy density, wide ignition limit, low ignition energy and fast combustion speed. Exhaust gas recirculation (EGR) technology + electric compressor and flow valve are used to regulate the combustion state in the cylinder of the hydrogen engine, avoid abnormal combustion problems that frequently occur under medium and high loads, and solve the contradiction between higher power output and NO emissions.

[0087] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0088] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0089] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0090] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0091] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0092] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0093] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0094] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A control method for a lean-burn hydrogen engine system, characterized in that: Determine the actual air-fuel ratio of the hydrogen engine in the current working condition and the designed air-fuel ratio in the current working condition to determine whether the engine is in a state of insufficient intake and hydrogen cannot stably burn; If yes, adjust the speed of the electric compressor (2) to increase the air intake; Otherwise, the intake uniformity coefficient is obtained, and the flow valve (100) and the high-pressure EGR valve (4) are controlled according to the design rules; Controlling the flow valve (100) and the high-pressure EGR valve (4) according to the design rules comprises the following steps: Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition; If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves (100) in the two intake pipes (1) are fully opened; If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves (100) and the opening of the high-pressure EGR valve (4) are adjusted to ensure that the hydrogen engine is in a state of uniform intake and stable combustion; Also included is a lean-burn hydrogen engine system, the lean-burn hydrogen engine system comprising: Two air intake pipelines (1) are connected in parallel between the air outlet of the electric compressor (2) and the air inlet of the intercooler (3), and the intercooler (3) is connected to the air inlet of the hydrogen engine; the air intake pipeline (1) comprises a flow valve (100) and a mechanical compressor (101) connected in sequence; Two exhaust gas boosting pipelines, one of which is connected to an exhaust port of a part of the cylinder body of the hydrogen engine, and the other is connected to an exhaust port of another part of the cylinder body of the hydrogen engine; the two exhaust gas boosting pipelines are connected in parallel with the vehicle aftertreatment system, and are both connected to an exhaust gas recirculation pipeline connected to the air inlet of the hydrogen engine, and a high-pressure EGR valve (4) is provided on the exhaust gas recirculation pipeline; A vehicle ECU (5) is signal-connected to the electric compressor (2), the flow valve (100) and the high-pressure EGR valve (4).

2. The control method of the lean-burn hydrogen engine system according to claim 1, characterized in that: The exhaust gas boost pipeline comprises a hydrogen engine exhaust manifold (11), the hydrogen engine exhaust manifold (11) is connected to a turbine (6) via a bypass valve, the turbine (6) is connected to the vehicle post-treatment system via an exhaust pipe (7), and the exhaust pipe (7) is also connected to the exhaust gas recirculation pipeline; The turbine (6) and the mechanical compressor (101) are mechanically connected.

3. The control method of the lean-burn hydrogen engine system according to claim 1 or 2, characterized in that: The exhaust gas recirculation pipeline comprises a high-pressure EGR pipe (8), the high-pressure EGR pipe (8) is connected to an EGR cooler (9), and the EGR cooler (9) is connected to an air intake of the hydrogen engine; The high-pressure EGR valve (4) is arranged on the high-pressure EGR pipe (8).

4. The control method of the lean-burn hydrogen engine system according to claim 1, characterized in that: It also includes a drive motor (10) connected to the output end of the hydrogen engine via a clutch; the clutch and the drive motor (10) are signal-connected to the vehicle ECU (5).

5. The control method of the lean-burn hydrogen engine system according to claim 3, characterized in that: Of the two air intake pipelines (1), one air intake pipeline (1) is connected to an air intake port of a part of a cylinder body of a hydrogen engine through an intercooler (3), and the other air intake pipeline (1) is connected to an air intake port of another part of a cylinder body of the hydrogen engine.

6. A control method for a lean-burn hydrogen engine system as claimed in claim 3, characterized in that: It includes: The lean-burn hydrogen engine system further comprises a drive motor (10) connected to the output end of the hydrogen engine via a clutch; the clutch and the drive motor (10) are signal-connected to the vehicle ECU (5); Determine the actual air-fuel ratio of the hydrogen engine in the current working condition and the designed air-fuel ratio in the current working condition to determine whether the engine is in a state of insufficient intake and hydrogen cannot stably burn; If yes, the bypass valves of the two exhaust gas boost lines are opened, and the power source is switched from the hydrogen engine to the drive motor (10) through the clutch; Otherwise, the intake uniformity coefficient is obtained, and the flow valve (100) and the high-pressure EGR valve (4) are controlled according to the design rules.

7. The control method of the lean-burn hydrogen engine system according to claim 6, characterized in that: Controlling the flow valve (100) and the high-pressure EGR valve (4) according to the design rules comprises the following steps: Compare the actual intake uniformity coefficient of the hydrogen engine under the current operating condition with the designed intake uniformity coefficient under the current operating condition; If the actual intake uniformity coefficient is less than or equal to the designed intake uniformity coefficient, the flow valves (100) in the two intake pipes (1) are fully opened; If the actual intake uniformity coefficient is greater than the designed intake uniformity coefficient, the openings of the two flow valves (100) and the opening of the high-pressure EGR valve (4) are adjusted, and the rotation speed of the electric compressor (2) is adjusted to ensure that the hydrogen engine is in a state of uniform intake and stable combustion.

8. A vehicle, characterized in that: It includes a control method for a lean-burn hydrogen engine system as described in any one of claims 1-5.

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