H2 internal combustion engine aftertreatment system, control method, and machine

Abstract

The application relates to an H2 internal combustion engine aftertreatment system, a control method and mechanical equipment in the technical field of tail gas treatment, the H2 internal combustion engine aftertreatment system comprising a hydrogen selective catalytic reducer, a hydrogen oxidation catalyst and an ammonia selective catalytic reducer which are sequentially communicated with tail gas of an H2 internal combustion engine; a urea nozzle is arranged between the ammonia selective catalytic reducer and the hydrogen oxidation catalyst; a nitrogen oxide sensor and a first temperature sensor are arranged between the urea nozzle and the hydrogen oxidation catalyst. The H2 internal combustion engine aftertreatment system can effectively reduce NOx emission and H2 emission, effectively reduce urea consumption and guarantee the nitrogen oxide detection effect of the nitrogen oxide sensor.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology, and in particular to an H2 internal combustion engine aftertreatment system, control method and mechanical equipment. Background Technology

[0002] The H2 internal combustion engine is a new type of internal combustion engine that effectively reduces CO2 emissions. However, the exhaust gas from an H2 internal combustion engine contains a large amount of unburned H2, and NOx is produced during the thermal formation mechanism of hydrogen fuel combustion. Currently, most aftertreatment systems for H2 internal combustion engines are similar to those for diesel engines, often employing an NH3-SCR system. H2 has a reducing effect and can reduce nitrogen oxides (NOx) pollutants in NH3-SCR. However, the concentration of H2 is generally difficult to measure, making it impossible to assess the amount of NOx consumed by H2 in NH3-SCR. This can lead to excessive urea injection in the urea injection system, resulting in excessive urea consumption and the generation of another pollutant, NH3. Furthermore, the presence of a large amount of unburned H2 in the exhaust gas makes NOx sensors susceptible to damage, hindering the detection of NOx in the exhaust gas. Summary of the Invention

[0003] In view of the problems existing in the background technology, this application provides an H2 internal combustion engine after-treatment system, control method and mechanical equipment, which can effectively reduce NOx emissions and H2 emissions, effectively reduce urea consumption, and ensure the effectiveness of the nitrogen oxide sensor in detecting nitrogen oxides.

[0004] According to a first aspect of the present invention, an aftertreatment system for an H2 internal combustion engine is provided, comprising a hydrogen selective catalytic reduction unit, a hydrogen oxidation catalyst, and an ammonia selective catalytic reduction unit sequentially connected to the exhaust gas of the H2 internal combustion engine; a urea nozzle is provided between the ammonia selective catalytic reduction unit and the hydrogen oxidation catalyst; and a nitrogen oxide sensor and a first temperature sensor are provided between the urea nozzle and the hydrogen oxidation catalyst.

[0005] In some embodiments of the present invention, a second temperature sensor is provided between the hydrogen oxidation catalyst and the hydrogen selective catalytic reduction device.

[0006] In some embodiments of the present invention, a third temperature sensor is provided on the inlet side of the hydrogen selective catalytic reduction device.

[0007] In some embodiments of the present invention, the urea nozzle, the nitrogen oxide sensor, the first temperature sensor, the second temperature sensor, and the third temperature sensor are connected to the control unit ECU.

[0008] According to a second aspect of the present invention, a control method for the above-mentioned H2 internal combustion engine aftertreatment system is provided, comprising the following steps: S1, determining whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst is greater than a preset temperature T1; if yes, then proceeding to S2; if no, then proceeding to S3; S2, determining whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction reactor is greater than a preset temperature T2 and less than a preset temperature T3; if yes, then proceeding to S4; if the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction reactor is less than or equal to the preset temperature T2, then proceeding to S5; S3, controlling the H2 internal combustion engine to burn in normal combustion mode; S4, controlling the H2 internal combustion engine to burn in high H2 exhaust combustion mode; S5, controlling the H2 internal combustion engine to maintain normal combustion mode.

[0009] In some embodiments of the present invention, the high H2 primary exhaust combustion mode is achieved by one or more of the following methods: significantly delaying the ignition advance angle, increasing the injection volume of concentrated H2, and secondary H2 injection.

[0010] In some embodiments of the present invention, the preset temperature T1 is set according to the H2 conversion capacity of the hydrogen oxidation catalyst.

[0011] In some embodiments of the present invention, after the H2 internal combustion engine enters the normal combustion mode, it is determined whether the temperature of the exhaust gas upstream of the urea nozzle reaches the preset temperature T4. If so, the urea nozzle is controlled to start.

[0012] According to a third aspect of the present invention, a mechanical device is provided, comprising the above-described H2 internal combustion engine aftertreatment system.

[0013] This application provides an H2 internal combustion engine aftertreatment system. This system, tailored to the emission characteristics of H2 internal combustion engines, fully utilizes the H2 produced from incomplete combustion in the exhaust gas as a reducing agent to convert a portion of the harmful NOx in the exhaust. This not only reduces the consumption of urea in the NH3-SCR but also places the H2-SCR at the forefront, effectively utilizing the temperature in the exhaust gas to improve the low-temperature NOx conversion efficiency. Furthermore, the presence of H2-SCR and HOC avoids damage to the NOx sensor caused by H2, improving the sensor's reliability. By controlling the original H2 internal combustion engine, the system utilizes the H2 in the original engine to reduce pollutant emissions, eliminating the need for new devices and effectively reducing system complexity and costs. Attached Figure Description

[0014] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0015] Figure 1 This is a schematic diagram of the overall structure of the H2 internal combustion engine aftertreatment system of the present invention;

[0016] Figure 2 This is a flowchart of the control method for the H2 internal combustion engine aftertreatment system of the present invention.

[0017] The labels in the attached diagram represent the following: 1. Third temperature sensor; 2. Hydrogen selective catalytic reduction unit; 3. Hydrogen oxidation catalyst; 4. Ammonia selective catalytic reduction unit; 5. Nitrogen oxide sensor; 6. First temperature sensor; 7. Urea nozzle; 8. Control unit (ECU); 9. Second temperature sensor. Detailed Implementation

[0018] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0019] In the following description, when referring to the accompanying drawings, the same numbers in different drawings denote the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0020] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0021] This application discloses an after-treatment system for an H2 internal combustion engine. For example... Figure 1 As shown, the H2 internal combustion engine aftertreatment system includes a hydrogen selective catalytic reduction (H2-SCR) 2, a hydrogen oxidation catalyst (HOC) 3, and an ammonia selective catalytic reduction (NH3-SCR) 4, which are sequentially connected to the exhaust gas of the H2 internal combustion engine; wherein, a urea nozzle 7 is provided between the ammonia selective catalytic reduction 4 and the hydrogen oxidation catalyst 3; a nitrogen oxide sensor 5 and a first temperature sensor 6 are provided between the urea nozzle 7 and the hydrogen oxidation catalyst 3.

[0022] By using the H2 internal combustion engine aftertreatment system in this technical solution, the H2 internal combustion engine generates exhaust gas. The exhaust gas first enters the hydrogen selective catalytic reduction (HCR) 2, where it catalyzes the reduction of nitrogen oxides by hydrogen in the exhaust gas. This reaction between hydrogen and nitrogen oxides simultaneously reduces the content of both hydrogen and nitrogen oxides in the exhaust gas. The exhaust gas then continues to the hydrogen oxidation catalyst 3, where it catalyzes the oxidation reaction between hydrogen and oxygen, further reducing the hydrogen content. Consequently, the hydrogen content in the exhaust gas that subsequently enters the ammonia selective catalytic reduction (ACR) 4 is significantly reduced, effectively mitigating or even eliminating the hydrogen content. In addition to eliminating the influence of hydrogen on the ammonia selective catalytic reduction unit 4 and protecting the nitrogen oxide sensor 5, the concentration of unreacted nitrogen oxides in the exhaust gas is measured by the nitrogen oxide sensor 5. The concentration is then detected by the first temperature sensor 6, and urea is injected within a suitable temperature range to obtain the urea needed to consume the nitrogen oxides. This portion of urea is hydrolyzed into NH3, which reacts with the nitrogen oxides in the ammonia selective catalytic reduction unit 4. Thus, this invention not only effectively reduces nitrogen oxide and hydrogen emissions but also effectively reduces urea consumption, ensuring the effectiveness of the nitrogen oxide sensor 5 in detecting nitrogen oxides.

[0023] Furthermore, by placing the hydrogen selective catalytic reduction unit 2 upstream of the hydrogen oxidation catalyst 3, this invention addresses the issue that during cold starts, when the ammonia selective catalytic reduction unit 4 is far from the H2 internal combustion engine and its temperature drops, which is detrimental to the NOx conversion of the ammonia selective catalytic reduction unit 4, the hydrogen selective catalytic reduction unit 2 has a higher conversion efficiency than the ammonia selective catalytic reduction unit 4 at low temperatures. This improves the NOx conversion effect of the H2 internal combustion engine aftertreatment system during cold starts and effectively reduces the pollutant content in the final exhaust gas emitted during cold starts.

[0024] In some embodiments of the present invention, such as Figure 1 As shown, a second temperature sensor 9 is also provided between the hydrogen oxidation catalyst 3 and the hydrogen selective catalytic reduction reactor 2.

[0025] Based on the hydrogen conversion efficiency of the hydrogen oxidation catalyst 3, the temperature of the exhaust gas entering the hydrogen oxidation catalyst 3 is detected by the second temperature sensor 9. When the exhaust gas temperature upstream of the hydrogen oxidation catalyst 3 exceeds a certain temperature, it indicates that the hydrogen oxidation catalyst 3 has a high hydrogen conversion efficiency, and can oxidize even a large amount of hydrogen in front of the hydrogen oxidation catalyst 3. If the exhaust gas temperature upstream of the hydrogen oxidation catalyst 3 is lower than a certain temperature, it indicates that the hydrogen oxidation catalyst 3 has a low hydrogen conversion efficiency and cannot handle a large amount of hydrogen. Based on this, the combustion mode of the H2 internal combustion engine can be adjusted to determine whether to select the normal combustion mode or the high H2 exhaust combustion mode, thereby controlling the hydrogen content in the exhaust gas. This ensures that when the hydrogen oxidation catalyst 3 has a high hydrogen conversion efficiency, the hydrogen content in the exhaust gas is increased, and that when the hydrogen oxidation catalyst 3 has a low hydrogen conversion efficiency, the hydrogen content in the exhaust gas is not too high.

[0026] In some embodiments of the present invention, such as Figure 1 As shown, a third temperature sensor 1 is provided on one side of the inlet of the hydrogen selective catalytic reduction unit 2.

[0027] In this invention, since the conversion efficiency of the hydrogen selective catalytic reducer 2 for NOx is lower than that of the ammonia selective catalytic reducer 4, and the hydrogen selective catalytic reducer 2 has a higher conversion efficiency than the ammonia selective catalytic reducer 4 at low temperatures, while the conversion efficiency of the hydrogen selective catalytic reducer 2 at high temperatures is much lower than that of the ammonia selective catalytic reducer 4, it is necessary to make full use of the conversion efficiency of the hydrogen selective catalytic reducer 2 at low temperatures, while using the ammonia selective catalytic reducer 4 at high temperatures.

[0028] The temperature of the exhaust gas entering the hydrogen selective catalytic reduction unit (H2-SCR) 2 is detected by the third temperature sensor 1. When the exhaust gas temperature upstream of the hydrogen oxidation catalyst 3 exceeds a certain temperature, it can be further determined whether the exhaust gas temperature upstream of the H2-SCR 2 exceeds the set temperature. If so, it indicates that the H2-SCR 2 has a high conversion efficiency for hydrogen, and the H2 internal combustion engine can be adjusted to burn in a high H2 exhaust combustion mode. Otherwise, it indicates that the H2-SCR 2 has a low conversion efficiency for hydrogen, and the H2 internal combustion engine can be kept burning in a normal combustion mode to ensure as complete combustion as possible. This fully utilizes the high low-temperature conversion efficiency of H2-SCR, allowing H2 to react with NOx in the exhaust pollutants, improving conversion efficiency, reducing the hydrogen content in the exhaust, and avoiding safety and reliability risks caused by excessive hydrogen emissions.

[0029] In some embodiments of the present invention, such as Figure 1 As shown, the urea nozzle 7, the nitrogen oxide sensor 5, the first temperature sensor 6, the second temperature sensor 9, and the third temperature sensor 1 are connected to the control unit ECU 8.

[0030] The vehicle control unit ECU8 receives signals from the nitrogen oxide sensor 5, the first temperature sensor 6, the second temperature sensor 9, and the third temperature sensor 1, and controls the urea injector 7, the H2 internal combustion engine, etc., to achieve the regulation of urea injection and the combustion mode of the H2 internal combustion engine.

[0031] In some embodiments of the present invention, the hydrogen selective catalytic reduction device 2 is a modified selective catalytic reduction system, which can better utilize the reducing properties of hydrogen, improve the conversion efficiency of hydrogen and nitrogen oxides in the selective catalytic reduction system, thereby making full use of the reaction between hydrogen and nitrogen oxides in the exhaust gas, while reducing the content of hydrogen and nitrogen oxides in the exhaust gas.

[0032] This embodiment also proposes a control method for the above-mentioned H2 internal combustion engine aftertreatment system, such as... Figure 2 As shown, the control method includes the following steps:

[0033] S0. First, confirm the H2 conversion capacity of hydrogen oxidation catalyst 3.

[0034] S1. Determine whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is greater than the preset temperature T1. If yes, execute S2; otherwise, execute S3.

[0035] In this invention, the preset temperature T1 is set according to the conversion capacity of the hydrogen oxidation catalyst 3 to H2. It should be understood that when the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is greater than the preset temperature T1, it indicates that the hydrogen oxidation catalyst 3 has a high conversion efficiency for hydrogen; otherwise, the hydrogen oxidation catalyst 3 has a low conversion efficiency for hydrogen.

[0036] S2. Determine whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit 2 is greater than the preset temperature T2 and less than the preset temperature T3. If yes, execute S4. If the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit 2 is less than or equal to the preset temperature T2, execute S5.

[0037] In this invention, the preset temperatures T2 and T3 are calibrated experimentally. It should be understood that when the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit 2 is greater than the preset temperature T2 and less than the preset temperature T3, the hydrogen selective catalytic reduction unit 2 has a high catalytic reaction efficiency for hydrogen and nitrogen oxides. When the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit 2 is less than the preset temperature T2, the hydrogen selective catalytic reduction unit 2 has a low catalytic reaction efficiency for hydrogen and nitrogen oxides.

[0038] S3 controls the H2 internal combustion engine to burn in normal combustion mode.

[0039] Since the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is lower than the preset temperature T1, the hydrogen oxidation catalyst 3 has a low conversion efficiency for hydrogen and cannot process a large amount of H2. By controlling the H2 internal combustion engine to burn in the normal combustion mode, a large amount of H2 can be avoided in the exhaust gas, thereby ensuring the percentage of hydrogen processed by the hydrogen selective catalytic reduction reactor 2 and the hydrogen oxidation catalyst 3, and reducing the amount of hydrogen passing through the nitrogen oxide sensor 5 and entering the ammonia selective catalytic reduction reactor 4.

[0040] In some embodiments of the present invention, after the H2 internal combustion engine enters the normal combustion mode, it is determined whether the temperature of the exhaust gas upstream of the urea injector 7 reaches the preset temperature T4. If so, the urea injector 7 is controlled to start. The preset temperature T4 can be set according to the optimal temperature range of urea injection, such as setting the preset temperature T4 to 180°C.

[0041] S4 controls the combustion mode of the H2 internal combustion engine's high H2 exhaust.

[0042] Since the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is higher than the preset temperature T1, the hydrogen oxidation catalyst 3 has a high conversion efficiency for hydrogen and can process a large amount of H2. By controlling the H2 internal combustion engine to burn in the high H2 exhaust combustion mode, the H2 content in the exhaust gas is increased by utilizing the combustion control of the H2 internal combustion engine itself.

[0043] In some embodiments of the present invention, the combustion mode of high H2 exhaust can be achieved by one or more of the following methods: significantly delaying the ignition advance angle, increasing the injection volume of concentrated H2, and secondary H2 injection.

[0044] S5 controls the H2 internal combustion engine to maintain normal combustion mode.

[0045] At this time, although the hydrogen oxidation catalyst 3 has a high conversion efficiency for hydrogen, the hydrogen selective catalytic reduction 2 has a low catalytic reaction efficiency for hydrogen and nitrogen oxides because the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction 2 is less than or equal to the preset temperature T2. By controlling the H2 internal combustion engine to maintain normal combustion mode and burn as completely as possible, the H2 content in the exhaust can be reduced, avoiding safety and reliability risks caused by excessive H2 emissions.

[0046] This embodiment also proposes a mechanical device, which includes the above-mentioned H2 internal combustion engine aftertreatment system. This mechanical device includes, but is not limited to, agricultural machinery, construction machinery, passenger vehicles, etc.

[0047] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control method for an H2 internal combustion engine aftertreatment system, characterized in that, The H2 internal combustion engine aftertreatment system includes a hydrogen selective catalytic reduction unit, a hydrogen oxidation catalyst, and an ammonia selective catalytic reduction unit that are sequentially connected to the exhaust gas of the H2 internal combustion engine; a urea nozzle is provided between the ammonia selective catalytic reduction unit and the hydrogen oxidation catalyst; a nitrogen oxide sensor and a first temperature sensor are provided between the urea nozzle and the hydrogen oxidation catalyst. The control method includes the following steps: S1. Determine whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst is greater than the preset temperature T1. If yes, proceed to S2; otherwise, proceed to S3. S2. Determine whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit is greater than the preset temperature T2 and less than the preset temperature T3. If yes, proceed to S4. If the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction unit is less than or equal to the preset temperature T2, proceed to S5. S3, Control the H2 internal combustion engine to burn in normal combustion mode; S4, control the combustion mode of the H2 internal combustion engine's high H2 exhaust; S5 controls the H2 internal combustion engine to maintain normal combustion mode.

2. The control method according to claim 1, characterized in that, A second temperature sensor is provided between the hydrogen oxidation catalyst and the hydrogen selective catalytic reduction device.

3. The control method according to claim 2, characterized in that, A third temperature sensor is provided on one side of the inlet of the hydrogen selective catalytic reduction device.

4. The control method according to claim 3, characterized in that, The urea nozzle, nitrogen oxide sensor, first temperature sensor, second temperature sensor, and third temperature sensor are connected to the control unit ECU.

5. The control method according to claim 1, characterized in that, The combustion mode of the high H2 exhaust is achieved by one or more of the following methods: significantly delaying the ignition advance angle, increasing the injection volume of concentrated H2, and secondary H2 injection.

6. The control method according to claim 1, characterized in that, The preset temperature T1 is set according to the H2 conversion capacity of the hydrogen oxidation catalyst.

7. The control method according to claim 1, characterized in that, After the H2 internal combustion engine enters the normal combustion mode, it determines whether the temperature of the exhaust gas upstream of the urea nozzle has reached the preset temperature T4. If so, it controls the urea nozzle to start.

8. A mechanical device, characterized in that, The mechanical equipment includes an H2 internal combustion engine aftertreatment system and is configured to perform the control method of the H2 internal combustion engine aftertreatment system as described in any one of claims 1-7.

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