Lean-burn hydrogen engine aftertreatment system, control method, engine, and vehicle

Abstract

The present application belongs to the field of vehicle technology, and discloses a lean hydrogen engine aftertreatment system, a control method, an engine and a vehicle. When the engine is in an equivalent ratio working condition, only the first valve is fully opened, exhaust gas skips the deoxidizer, and is treated by a three-way catalytic converter to meet the NOx emission requirement. When lambda is greater than 1 and the detection value P of the second oxygen concentration detection element is less than P limit , the engine enters a lean working condition, the second valve is controlled to be opened so that part of the exhaust gas is treated by the deoxidizer and then enters the three-way catalytic converter to meet the emission requirement. When lambda is greater than 1 and P is greater than or equal to P limit , the engine enters a regeneration working condition, the first valve is fully closed, the second valve is fully opened, the exhaust gas is treated by the deoxidizer and then enters the three-way catalytic converter, the third valve is opened, the crankcase ventilation system is connected to the crankcase ventilation through the regeneration pipeline, the regeneration of the deoxidizer carrier is completed, the oxygen concentration in the exhaust gas is reduced, and the emission of NOx is controlled.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a lean-burn hydrogen engine after-treatment system, a control method, an engine, and a vehicle. Background Art

[0002] Lean-burn hydrogen engines have the advantages of high thermal efficiency, low conventional emissions, and zero carbon dioxide emissions. Lean-burn hydrogen engines use a mixture with an excess air coefficient greater than 2, which will cause a high oxygen content in the cylinder and a high temperature in the cylinder during combustion. Therefore, the main pollutant produced during the hydrogen combustion process is NOx. Especially for turbocharged hydrogen engines, NOx emissions can even reach 7000ppm. In addition, a small amount of lubricating oil enters the cylinder and burns to form HC (hydrocarbons) and CO, but its content is very low and can be ignored. Therefore, NOx emission control is an issue that must be solved in the development of lean-burn hydrogen engine technology. The NOx conversion efficiency in the lean-burn hydrogen engine after-treatment system needs to be further improved to control NOx emissions.

[0003] To address the above issues, most existing technologies have eliminated the TWC (three-way catalytic converter) and instead adopted an additional NOx catalyst. There are mainly the following solutions:

[0004] (1) An ammonia selective catalytic reducer (NH3-SCR), such as patent application number CN202111214517.7, introduces an additional reducing agent to chemically convert NOx into nitrogen and water to achieve NOx emission control. However, the ammonia selective catalytic reducer requires regular refilling of the reducing agent. Furthermore, the reducer system is large and has high requirements for vehicle layout, making this solution difficult to apply to light passenger vehicles.

[0005] (2) Setting up a hydrogen selective catalytic reducer (H2-SCR). For example, in the patent application number CN202211694194.0, hydrogen can be used directly as the reducing agent, eliminating the need for storage devices, thereby reducing the volume of the post-treatment catalytic system, reducing costs, and enabling application in light passenger vehicles. However, H2-SCR is easily affected by water vapor contained in the exhaust gas, leading to catalyst poisoning. At the same time, when using H2-SCR, hydrogen needs to be frequently injected, which is difficult to control, making it difficult to apply.

[0006] (3) Install a NOx trap (LNT). Compared to a TWC, a NOx trap can chemically store NOx in the exhaust of a lean-burn hydrogen engine in alkaline earth compounds in the form of nitrates or nitrites to achieve NOx emission control. However, the NOx trap has a storage limit. In this case, injecting hydrogen into the LNT as a reducing agent places high demands on the engine control system and also affects the overall thermal efficiency of the engine.

[0007] In summary, existing lean-burn hydrogen engine aftertreatment systems face challenges in simultaneously balancing NOx conversion efficiency, engine thermal efficiency, aftertreatment system volume, and control difficulty. Therefore, a lean-burn hydrogen engine aftertreatment system, control method, engine, and vehicle are urgently needed to address these issues. Summary of the Invention

[0008] The purpose of the present invention is to provide a lean-burn hydrogen engine after-treatment system, control method, engine and vehicle, which improve the NOx conversion efficiency and engine thermal efficiency without the need for additional injection of reducing agent, and solve the problems of high control difficulty and large system size of existing lean-burn hydrogen engine after-treatment systems.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, a lean-burn hydrogen engine aftertreatment system is provided for treating gas exhausted from an engine combustion system, the lean-burn hydrogen engine aftertreatment system comprising an exhaust manifold, an initial exhaust line, a terminal exhaust line, and an electronic control unit;

[0011] The engine combustion system discharges raw exhaust gas through the exhaust manifold, the exhaust manifold is connected to the initial exhaust pipeline, the initial exhaust pipeline branches out into a bypass pipeline and a deoxidation pipeline, the bypass pipeline and the deoxidation pipeline are connected in parallel and then connected in series with the terminal exhaust pipeline, and the terminal exhaust pipeline is provided with a NOx concentration detector, a first oxygen concentration detector and a three-way catalytic converter in sequence along the airflow direction;

[0012] The bypass pipeline is provided with a first valve;

[0013] The deoxygenation pipeline is provided with a second valve, a deoxygenator and a second oxygen concentration detection element, and the second oxygen concentration detection element is provided downstream of the deoxygenator;

[0014] The deoxidation pipeline is connected to a regeneration pipeline upstream of the deoxidizer, and the regeneration pipeline is provided with a third valve and a crankcase ventilation system;

[0015] The electronic control unit is used to control the opening and closing and the opening degree of the first valve and the second valve according to the detection values ​​of the NOx concentration detection element and the first oxygen concentration detection element, and the electronic control unit is used to control the opening and closing of the third valve according to the detection value of the second oxygen concentration detection element.

[0016] As a preferred solution of the lean-burn hydrogen engine after-treatment system provided by the present invention, the second valve is arranged upstream of the deoxidizer, and the regeneration pipeline is connected between the second valve and the deoxidizer.

[0017] As a preferred solution of the lean-burn hydrogen engine after-treatment system provided by the present invention, the initial exhaust pipeline, the bypass pipeline, the deoxidation pipeline, the regeneration pipeline and the terminal exhaust pipeline are all pipelines that have been subjected to thermal insulation treatment.

[0018] As a preferred solution of the lean-burn hydrogen engine aftertreatment system provided by the present invention, when the third valve is opened, the amount of fuel provided by the crankcase ventilation system is greater than the oxygen loading of the deoxidizer carrier in the deoxidizer.

[0019] As a preferred solution of the lean-burn hydrogen engine after-treatment system provided by the present invention, the NOx concentration detection component includes a NOx concentration sensor.

[0020] As a preferred solution of the lean-burn hydrogen engine after-treatment system provided by the present invention, the first oxygen concentration detection component and the second oxygen concentration detection component both include oxygen concentration sensors.

[0021] In a second aspect, a lean-burn hydrogen engine aftertreatment system control method is provided, which is controlled by applying the lean-burn hydrogen engine aftertreatment system as described above, and the lean-burn hydrogen engine aftertreatment system control method comprises the following steps:

[0022] S1. Determine whether the excess air coefficient value λ of the engine is greater than 1. If so, execute S3; if not, execute S2;

[0023] S2: The engine enters an equivalence ratio operating condition, and the electronic control unit controls the first valve to be fully open, the second valve to be fully closed, and the third valve to be fully closed;

[0024] S3: Compare the detection value P of the second oxygen concentration detector with the oxygen concentration threshold value P limit , if P <P limit , then execute S4, otherwise execute S8;

[0025] S4: The engine enters a lean-burn mode, and further determines the oxygen partial pressure P obtained by the first oxygen concentration detection element. O2 and the NOx partial pressure P obtained by the NOx concentration detecting element NOx The size of P O2 >P NOx , then execute S5, if P O2 =P NOx , then execute S6, if P O2 <P NOx , then execute S7;

[0026] S5, the electronic control unit controls the opening of the first valve to decrease, the opening of the second valve to increase, and the third valve to fully close;

[0027] S6, the electronic control unit controls the opening of the first valve and the opening of the second valve to remain unchanged, and controls the third valve to be fully closed;

[0028] S7, the electronic control unit controls the opening of the first valve to increase, the opening of the second valve to decrease, and the third valve to fully close;

[0029] S8: The engine enters the regeneration mode and further determines the oxygen partial pressure P obtained by the first oxygen concentration detection element. O2 and the NOx partial pressure P obtained by the NOx concentration detecting element NOx The size of P O2 >P NOx , then execute S9, if P O2 =P NOx , then execute S10, if P O2 <P NOx , then execute S11;

[0030] S9, the electronic control unit controls the first valve to be fully closed, the second valve to be fully opened, and the opening of the third valve to be increased;

[0031] S10, the electronic control unit controls the first valve to be fully closed, the second valve to be fully open, and the opening of the third valve to remain unchanged;

[0032] S11 , the electronic control unit controls the first valve to be fully closed, the second valve to be fully open, and the opening of the third valve to be reduced.

[0033] As a preferred embodiment of the lean-burn hydrogen engine after-treatment system control method provided by the present invention, before step S1, the method further includes step S0: determining whether the engine is started, and if so, executing step S1, otherwise terminating;

[0034] After step S2, step S5, step S6, step S7, step S9, step S10 and step S11, step S12 is executed: determine whether the engine is running; if so, return to step S1; otherwise, end.

[0035] In a third aspect, an engine is provided, comprising the lean-burn hydrogen engine after-treatment system as described in the first aspect above.

[0036] In a fourth aspect, a vehicle is provided, comprising the engine as described in the third aspect above.

[0037] Beneficial effects of the present invention:

[0038] The present invention provides a lean-burn hydrogen engine aftertreatment system, control method, engine, and vehicle. The engine combustion system burns hydrogen to form raw exhaust gas, which then enters an initial exhaust line through an exhaust manifold. An electronic control unit controls the oxygen partial pressure in the exhaust gas by controlling the openings of a first valve and a second valve. The exhaust gas ultimately enters a three-way catalytic converter in a terminal exhaust line to treat HC, CO, and NOx. The electronic control unit selectively opens a third valve based on the detection value of a second oxygen concentration detector, allowing the crankcase ventilation system to introduce crankcase ventilation gas (primarily composed of H2, CO, and HC) to react with oxygen in a deoxidizer carrier in the deoxidizer, thereby regenerating the deoxidizer carrier.

[0039] Specifically, the engine includes equivalence ratio operating condition, lean burn operating condition and regeneration operating condition. In equivalence ratio operating condition, the engine's excess air coefficient λ is 1, only the first valve is fully open, the second valve and the third valve are fully closed, the exhaust gas skips the deoxidizer, and is processed by the three-way catalytic converter to meet the NOx emission requirements. When λ is greater than 1, and the detection value P of the second oxygen concentration detector is <P limit When λ is greater than 1, and the detection value of the second oxygen concentration detector P≥P limit During this period, the engine enters regeneration mode, where the exhaust oxygen concentration is higher than during lean-burn mode, necessitating further reduction of the oxygen partial pressure during regeneration. At this point, the first valve is fully closed to prevent untreated exhaust from entering the three-way catalytic converter. The second valve is fully opened, allowing the exhaust to pass through the deoxidizer before entering the three-way catalytic converter. Simultaneously, the third valve opens, allowing the crankcase ventilation system to enter the crankcase through the regeneration line. The crankcase ventilation reacts with the oxygen in the deoxidizer carrier in the deoxidizer, regenerating the deoxidizer carrier and reducing the oxygen concentration in the exhaust. Simultaneously, the heat generated during the regeneration process also increases the efficiency of the three-way catalytic converter, thereby keeping NOx emissions within the specified range. By eliminating the need for an additional NOx catalytic reducer, this system improves NOx conversion efficiency and engine thermal efficiency while addressing the challenges of existing lean-burn hydrogen engine aftertreatment systems, which are difficult to control and bulky. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of a lean-burn hydrogen engine aftertreatment system provided by a specific embodiment of the present invention;

[0041] Figure 2 It is a flow chart of a lean-burn hydrogen engine after-treatment system control method provided by a specific embodiment of the present invention.

[0042] In the picture:

[0043] 1. Engine combustion system; 2. Exhaust manifold; 3. Initial exhaust line; 4. Bypass line; 5. Deoxidation line; 6. Regeneration line; 7. Terminal exhaust line; 8. Electronic control unit;

[0044] 41. First valve;

[0045] 51. Second valve; 52. Deaerator; 53. Second oxygen concentration detection element;

[0046] 61. Third valve; 62. Crankcase ventilation system;

[0047] 71. NOx concentration detection element; 72. First oxygen concentration detection element; 73. Three-way catalytic converter. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0049] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0050] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0051] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0052] like Figure 1 As shown, this embodiment provides a lean-burn hydrogen engine aftertreatment system for treating gases exhausted from an engine combustion system 1 to effectively control NOx emissions. The lean-burn hydrogen engine aftertreatment system includes an exhaust manifold 2, an initial exhaust line 3, a terminal exhaust line 7, and an electronic control unit 8.

[0053] The engine combustion system 1 discharges the original exhaust gas through the exhaust manifold 2, which is connected to the initial exhaust pipe 3. The initial exhaust pipe 3 branches out a bypass pipe 4 and a deoxidation pipe 5. The bypass pipe 4 and the deoxidation pipe 5 are connected in parallel and then connected in series with the terminal exhaust pipe 7. The terminal exhaust pipe 7 is provided with a NOx concentration detector 71, a first oxygen concentration detector 72 and a three-way catalytic converter 73 (i.e., TWC) in the direction of air flow; the bypass pipe 4 is provided with a first valve 41; the deoxidation pipe 5 is provided with a second valve 51 and a deoxidizer 52. And a second oxygen concentration detection element 53, the second oxygen concentration detection element 53 is arranged downstream of the deoxidizer 52; the deoxidation pipeline 5 is connected to the regeneration pipeline 6 upstream of the deoxidizer 52, and the regeneration pipeline 6 is provided with a third valve 61 and a crankcase ventilation system 62; the electronic control unit 8 is used to control the opening and closing and the opening degree of the first valve 41 and the second valve 51 according to the detection values ​​of the NOx concentration detection element 71 and the first oxygen concentration detection element 72, and the electronic control unit 8 is used to control the opening and closing of the third valve 61 according to the detection value of the second oxygen concentration detection element 53.

[0054] The engine combustion system 1 and exhaust manifold 2 form an engine module, which functions to generate the engine's raw exhaust. The first valve 41, deoxidizer 52, second valve 51, NOx concentration detector 71, and first oxygen concentration detector 72 form an oxygen concentration control module, which functions to control the oxygen partial pressure before the three-way catalytic converter 73. The crankcase ventilation system 62, third valve 61, and second oxygen concentration detector 53 constitute the deoxidizer carrier regeneration system of the deoxidizer 52, which functions to introduce crankcase ventilation into the deoxidizer 52 to achieve regeneration of the deoxidizer carrier. The three-way catalytic converter 73 and first oxygen concentration detector 72 form a three-way catalytic conversion module, which functions to treat CO, HC, and NOx emissions in the exhaust.

[0055] Engine combustion system 1 burns hydrogen to form raw exhaust gas, which then enters primary exhaust line 3 through exhaust manifold 2. Electronic control unit 8 controls the oxygen partial pressure in the exhaust gas by controlling the openings of first valve 41 and second valve 51. The exhaust gas ultimately enters three-way catalytic converter 73 in terminal exhaust line 7, where it treats HC, CO, and NOx. Based on the detection value of second oxygen concentration detector 53, electronic control unit 8 selectively opens third valve 61, allowing crankcase ventilation system 62 to introduce crankcase ventilation (primarily composed of H2, CO, and HC). This reacts with the oxygen in the deoxidizer carrier in deoxidizer 52, completing the regeneration of the deoxidizer carrier.

[0056] Specifically, the engine includes equivalence ratio operating condition, lean burn operating condition and regeneration operating condition. In equivalence ratio operating condition, the engine's excess air coefficient λ is 1, only the first valve 41 is fully open, the second valve 51 and the third valve 61 are fully closed, the exhaust gas skips the deoxidizer 52, and is processed by the three-way catalytic converter 73 to meet the NOx emission requirements. When λ is greater than 1, and the detection value P of the second oxygen concentration detector 53 is <P limit When λ is greater than 1, and the detection value P of the second oxygen concentration detector 53 is greater than P limit When the engine enters the regeneration mode, the oxygen concentration in the exhaust gas is higher than that in the lean-burn mode, requiring further reduction of the oxygen partial pressure during the regeneration phase. At this time, the first valve 41 is fully closed to prevent the exhaust gas from entering the three-way catalytic converter 73 directly without treatment. The second valve 51 is fully opened to allow the exhaust gas to pass through the deoxidizer 52 before entering the three-way catalytic converter 73. At the same time, the third valve 61 is opened, and the crankcase ventilation system 62 is introduced into the crankcase ventilation through the regeneration line 6. The crankcase ventilation reacts with the oxygen in the deoxidizer carrier to complete the regeneration of the deoxidizer carrier and reduce the oxygen concentration in the exhaust gas. At the same time, the heat generated during the regeneration process also improves the efficiency of the three-way catalytic converter 73, thereby controlling NOx emissions within the specified range. Since no additional NOx catalytic reducer is provided, the problem of high control difficulty and large system size of the existing lean-burn hydrogen engine after-treatment system is solved while improving NOx conversion efficiency and engine thermal efficiency.

[0057] Furthermore, during lean-burn operation, the openings of the first valve 41 and the second valve 51 are negatively feedback controlled by the electronic control unit 8 based on the detection values ​​of the NOx concentration detector 71 and the first oxygen concentration detector 72. During regeneration operation, the opening of the third valve 61 is negatively feedback controlled by the electronic control unit 8 based on the detection values ​​of the NOx concentration detector 71 and the first oxygen concentration detector 72.

[0058] See also Figure 1 The second valve 51 is arranged upstream of the deoxidizer 52 to effectively control the exhaust gas volume entering the deoxidizer 52 . The regeneration line 6 is connected between the second valve 51 and the deoxidizer 52 . The ventilation volume of the crankcase ventilation system 62 is only controlled by the third valve 61 .

[0059] Preferably, the initial exhaust pipe 3, the bypass pipe 4, the deoxidation pipe 5, the regeneration pipe 6 and the terminal exhaust pipe 7 are all heat-insulated pipes to avoid the exhaust temperature from dropping and affecting the efficiency of the catalyst in the system.

[0060] Preferably, when the third valve 61 is opened, the amount of fuel provided by the crankcase ventilation system 62 is greater than the oxygen loading of the deoxidizer carrier in the deoxidizer 52 to ensure complete regeneration of the deoxidizer carrier.

[0061] Preferably, the catalyst formulation of the three-way catalytic converter 73 uses a Pt noble metal catalyst, avoiding the use of Pd and Rh noble metal catalysts; the catalyst formulation of the deoxidizer carrier uses a cerium-zirconium solid solution with high oxygen storage capacity.

[0062] Signals are transmitted between the electronic control unit 8 and the NOx concentration detection element 71, the first oxygen concentration detection element 72, and the second oxygen concentration detection element 53 via wires. Optionally, the NOx concentration detection element 71 includes a NOx concentration sensor. The first oxygen concentration detection element 72 and the second oxygen concentration detection element 53 both include oxygen concentration sensors.

[0063] like Figure 2 As shown, this embodiment also provides a lean-burn hydrogen engine after-treatment system control method, which is controlled by the lean-burn hydrogen engine after-treatment system as described above. The lean-burn hydrogen engine after-treatment system control method includes the following steps:

[0064] S0: Determine whether the engine is started. If it is started, execute S1; otherwise, end.

[0065] S1. Determine whether the excess air coefficient value λ of the engine is greater than 1. If so, execute S3; if not, execute S2.

[0066] Specifically, the electronic control unit 8 determines whether the lambda value of the engine mixer is greater than 1.

[0067] S2: The engine enters the equivalence ratio operating condition, and the electronic control unit 8 controls the first valve 41 to be fully opened, the second valve 51 to be fully closed, and the third valve 61 to be fully closed. Subsequently, step S12 is executed.

[0068] At this time, the exhaust gas skips the deoxidizer 52 and enters the three-way catalytic converter 73 through the bypass line 4, thereby meeting the emission requirements.

[0069] S3, compare the detection value P of the second oxygen concentration detection member 53 with the oxygen concentration threshold value P limit , if P limit , execute S4, otherwise execute S8.

[0070] The detection value of the second oxygen concentration detection member 53 is collected by the electronic control unit 8 and compared with the preset oxygen concentration threshold value P limit of the deoxidizer carrier after deoxidization.

[0071] S4, the engine enters the lean burn condition, and further judge the size of the oxygen partial pressure P O2 obtained by the first oxygen concentration detection member 72 and the NOx partial pressure P NOx obtained by the NOx concentration detection member 71, if P O2 >P NOx , execute S5, if P O2 =P NOx , execute S6, if P O2 <P NOx , execute S7.

[0072] Specifically, the oxygen partial pressure P O2 obtained by the first oxygen concentration detection member 72 and the NOx partial pressure P NOx obtained by the NOx concentration detection member 71 are collected by the electronic control unit 8 and compared.

[0073] S5, since P O2 >P NOx , at this time, the oxygen partial pressure P O2 needs to be reduced to improve the conversion efficiency of the three-way catalytic converter 73. Therefore, the electronic control unit 8 controls the first valve 41 to reduce the opening, the second valve 51 to increase the opening, and the third valve 61 to be fully closed, and more exhaust gas is treated by the deoxidizer 52. Then, step S12 is executed.

[0074] S6, since P O2 =P NOx , at this time, the oxygen partial pressure P O2 does not need to be changed. The electronic control unit 8 controls the opening of the first valve 41 and the opening of the second valve 51 to remain unchanged, and controls the third valve 61 to be fully closed. Then, step S12 is executed.

[0075] S7, since P O2 <P NOx , at this time, the oxygen partial pressure P O2 needs to be increased. The electronic control unit 8 controls the first valve 41 to increase the opening, the second valve 51 to reduce the opening, and the third valve 61 to be fully closed, and more oxygen directly enters the three-way catalytic converter 73 through the bypass pipeline 4. Then, step S12 is executed.

[0076] S8: The engine enters the regeneration mode and further determines the oxygen partial pressure P obtained by the first oxygen concentration detection element 72. O2 and the NOx partial pressure P obtained by the NOx concentration detection member 71 NOx The size of P O2 >P NOx , then execute S9, if P O2 =P NOx , then execute S10, if P O2 <P NOx , then execute S11.

[0077] Specifically, the electronic control unit 8 collects the oxygen partial pressure P obtained by the first oxygen concentration detection element 72. O2 and the NOx partial pressure P obtained by the NOx concentration detection element 71 NOx , and compare them.

[0078] S9, due to P O2 >P NOx , at this time it is necessary to reduce the oxygen partial pressure P O2 To improve the conversion efficiency of the three-way catalytic converter 73, the electronic control unit 8 controls the first valve 41 to be fully closed, the second valve 51 to be fully open, and the third valve 61 to be opened more widely. All exhaust gas passes through the deoxidizer 52, and the ventilation volume of the crankcase ventilation system 62 is increased, promoting the regeneration of the deoxidizer carrier. Subsequently, step S12 is executed.

[0079] S10, due to P O2 =P NOx , there is no need to change the oxygen partial pressure P O2 The electronic control unit 8 controls the first valve 41 to be fully closed, the second valve 51 to be fully open, and the opening degree of the third valve 61 to remain unchanged. Then, step S12 is executed.

[0080] S11, due to P O2 <P NOx , at this time it is necessary to increase the oxygen partial pressure P O2 Therefore, the electronic control unit 8 controls the first valve 41 to be fully closed, the second valve 51 to be fully open, and the opening of the third valve 61 to be reduced, thereby reducing the regeneration of the deoxidizer carrier. Subsequently, step S12 is executed.

[0081] S12: Determine whether the engine is running. If so, return to step S1; otherwise, end.

[0082] This embodiment also provides an engine and a vehicle including the engine. The engine includes the lean-burn hydrogen engine after-treatment system as described above and is controlled by the lean-burn hydrogen engine after-treatment system control method as described above so that NOx emissions meet requirements.

[0083] Specifically, the engine operates in equivalence ratio, lean burn, and regeneration conditions. During equivalence ratio operation, the engine's excess air coefficient λ is 1, with only first valve 41 fully open and second and third valves 51 and 61 fully closed. Exhaust gas bypasses deoxidizer 52 and is treated by three-way catalytic converter 73 to meet NOx emission requirements.

[0084] When λ is greater than 1, and the detection value P of the second oxygen concentration detection element 53 is <P limit When the engine enters the lean-burn condition, the oxygen concentration in the exhaust gas is higher than that in the equivalence condition. The second valve 51 needs to be controlled to open so that part of the exhaust gas passes through the deoxidizer 52 before entering the three-way catalytic converter 73 to meet the NOx emission requirements.

[0085] In the lean-burn condition, the openings of the first valve 41 and the second valve 51 are negatively feedback controlled by the electronic control unit 8 according to the detection values ​​of the NOx concentration detection element 71 and the first oxygen concentration detection element 72 .

[0086] When λ is greater than 1, and the detection value P of the second oxygen concentration detection element 53 is greater than or equal to P limit When the engine enters the regeneration condition, the oxygen concentration in the exhaust gas is higher than that in the lean-burn condition, and the oxygen partial pressure in the exhaust gas needs to be further reduced. At this time, the first valve 41 is fully closed to prevent the exhaust gas from entering the three-way catalytic converter 73 directly without being treated. The second valve 51 is fully opened to allow all the exhaust gas to be processed by the deoxidizer 52 before entering the three-way catalytic converter 73. At the same time, the third valve 61 is opened, and the crankcase ventilation system 62 is introduced into the crankcase ventilation through the regeneration line 6. The crankcase ventilation reacts with the oxygen in the deoxidizer carrier to complete the regeneration of the deoxidizer carrier and reduce the oxygen concentration in the exhaust gas. At the same time, the heat generated by the regeneration process also improves the efficiency of the three-way catalytic converter 73, thereby controlling the NOx emission within the specified range.

[0087] In the regeneration mode, the opening of the third valve 61 is negatively feedback controlled by the electronic control unit 8 according to the detection values ​​of the NOx concentration detection element 71 and the first oxygen concentration detection element 72 .

[0088] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A lean-burn hydrogen engine aftertreatment system for treating the gas discharged from the engine combustion system (1), characterized in that: The lean-burn hydrogen engine after-treatment system comprises an exhaust manifold (2), an initial exhaust pipeline (3), a terminal exhaust pipeline (7), and an electronic control unit (8); The engine combustion system (1) discharges raw exhaust gas through the exhaust manifold (2), the exhaust manifold (2) is connected to the initial exhaust pipeline (3), the initial exhaust pipeline (3) branches out into a bypass pipeline (4) and a deoxidation pipeline (5), the bypass pipeline (4) and the deoxidation pipeline (5) are connected in parallel and then connected in series with the terminal exhaust pipeline (7), and the terminal exhaust pipeline (7) is provided with a NOx concentration detector (71), a first oxygen concentration detector (72) and a three-way catalytic converter (73) in sequence along the airflow direction; The bypass line (4) is provided with a first valve (41); The deoxidation pipeline (5) is provided with a second valve (51), a deoxidizer (52) and a second oxygen concentration detection element (53), and the second oxygen concentration detection element (53) is provided downstream of the deoxidizer (52); The deoxidation pipeline (5) is connected to a regeneration pipeline (6) upstream of the deoxidizer (52), and the regeneration pipeline (6) is provided with a third valve (61) and a crankcase ventilation system (62); The electronic control unit (8) is used to control the opening and closing and the opening degree of the first valve (41) and the second valve (51) according to the detection values ​​of the NOx concentration detection element (71) and the first oxygen concentration detection element (72), and the electronic control unit (8) is used to control the opening and closing of the third valve (61) according to the detection value of the second oxygen concentration detection element (53).

2. The lean-burn hydrogen engine aftertreatment system according to claim 1, characterized in that: The second valve (51) is arranged upstream of the deoxidizer (52), and the regeneration pipeline (6) is connected between the second valve (51) and the deoxidizer (52).

3. The lean-burn hydrogen engine aftertreatment system according to claim 1, characterized in that: The initial exhaust pipeline (3), the bypass pipeline (4), the deoxidation pipeline (5), the regeneration pipeline (6) and the terminal exhaust pipeline (7) are all pipelines that have been subjected to heat insulation treatment.

4. The lean-burn hydrogen engine aftertreatment system according to claim 1, characterized in that: When the third valve (61) is opened, the amount of fuel provided by the crankcase ventilation system (62) is greater than the oxygen loading capacity of the deoxidizer carrier in the deoxidizer (52).

5. The lean-burn hydrogen engine aftertreatment system according to any one of claims 1 to 4, characterized in that: The NOx concentration detecting member (71) includes a NOx concentration sensor.

6. The lean-burn hydrogen engine aftertreatment system according to any one of claims 1 to 4, characterized in that: The first oxygen concentration detecting element (72) and the second oxygen concentration detecting element (53) both include oxygen concentration sensors.

7. A lean-burn hydrogen engine after-treatment system control method, characterized in that: The lean-burn hydrogen engine after-treatment system according to any one of claims 1 to 6 is used for control, and the lean-burn hydrogen engine after-treatment system control method comprises the following steps: S1. Determine whether the excess air coefficient value λ of the engine is greater than 1. If so, execute S3; if not, execute S2; S2, the engine enters an equivalence ratio operating condition, the electronic control unit (8) controls the first valve (41) to be fully open, the second valve (51) to be fully closed, and the third valve (61) to be fully closed; S3, comparing the detection value P of the second oxygen concentration detection element (53) with the oxygen concentration threshold value P limit , if P <P limit , then execute S4, otherwise execute S8; S4, the engine enters the lean-burn state, and further determines the oxygen partial pressure P obtained by the first oxygen concentration detection element (72). O2 and the NOx partial pressure P obtained by the NOx concentration detection element (71) NOx The size of P O2 >P NOx , then execute S5, if P O2 =P NOx , then execute S6, if P O2 <P NOx , then execute S7; S5, the electronic control unit (8) controls the opening of the first valve (41) to decrease, the opening of the second valve (51) to increase, and the third valve (61) to fully close; S6, the electronic control unit (8) controls the opening of the first valve (41) and the opening of the second valve (51) to remain unchanged, and controls the third valve (61) to be fully closed; S7, the electronic control unit (8) controls the opening of the first valve (41) to increase, the opening of the second valve (51) to decrease, and the third valve (61) to fully close; S8, the engine enters the regeneration mode, and further determines the oxygen partial pressure P obtained by the first oxygen concentration detection element (72) O2 and the NOx partial pressure P obtained by the NOx concentration detection element (71) NOx The size of P O2 >P NOx , then execute S9, if P O2 =P NOx , then execute S10, if P O2 <P NOx , then execute S11; S9, the electronic control unit (8) controls the first valve (41) to be fully closed, the second valve (51) to be fully opened, and the opening degree of the third valve (61) to be increased; S10, the electronic control unit (8) controls the first valve (41) to be fully closed, the second valve (51) to be fully open, and the opening degree of the third valve (61) to remain unchanged; S11, the electronic control unit (8) controls the first valve (41) to be fully closed, the second valve (51) to be fully open, and the opening degree of the third valve (61) to be reduced.

8. The lean-burn hydrogen engine after-treatment system control method according to claim 7, characterized in that: Before step S1, the process further includes step S0: determining whether the engine is started, if so, executing S1, otherwise ending; After step S2, step S5, step S6, step S7, step S9, step S10 and step S11, step S12 is executed: determine whether the engine is running; if so, return to step S1; otherwise, end.

9. An engine, characterized in that The invention comprises a lean-burn hydrogen engine after-treatment system as described in any one of claims 1 to 6.

10. A vehicle, characterized in that Comprising the engine of claim 9.

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