H2 internal combustion engine aftertreatment system, control method and mechanical equipment

Abstract

The invention relates to an H2 internal combustion engine post-treatment system, a control method and mechanical equipment in the technical field of tail gas treatment. The H2 internal combustion engine post-treatment system comprises 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 gas selective catalytic reducer and the hydrogen oxidation catalyst; and a nitrogen oxide sensor and a first temperature sensor are arranged between the urea nozzle and the hydrogen oxidation catalyst. According to the H2 internal combustion engine aftertreatment system, NOx emission and H2 emission can be effectively reduced, the urea consumption can be effectively reduced, and the nitric oxide detection effect of the nitric oxide sensor is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of tail gas treatment technology, in particular to a method for treating H 2 Internal combustion engine aftertreatment system, control method and mechanical equipment. Background Art

[0002] H 2 Internal combustion engines are an effective way to reduce CO 2 New internal combustion engine with emissions, H 2 The exhaust gas of internal combustion engines contains a large amount of incompletely burned H 2 , and NOx will be generated due to the thermal formation mechanism when hydrogen fuel is burned. 2 Most of the aftertreatment for internal combustion engines is similar to that for diesel engines, and NH 3 -SCR system, while H 2 It has a reducing effect and can be used in NH 3 -SCR reduces nitrogen oxide (NOx) pollutants. 2 The concentration is difficult to measure and it is not possible to assess H 2 In NH 3 -The amount of NOx consumed in the SCR causes excessive urea injection in the urea injection system, resulting in excessive urea consumption and the generation of another pollutant, NH 3 , and a large amount of incompletely burned H 2 The presence of makes the NOx sensor vulnerable to damage, which is not conducive to the detection of NOx in the exhaust gas. Summary of the invention

[0003] In view of the problems existing in the background technology, the present application provides a H 2 Internal combustion engine aftertreatment system, control method and mechanical equipment can effectively reduce NOx emissions and H 2 Emissions, and can effectively reduce urea consumption, ensuring the effectiveness of the nitrogen oxide sensor in detecting nitrogen oxides.

[0004] According to a first aspect of the present invention, there is provided a 2 Internal combustion engine aftertreatment system, including H 2 The exhaust gas of the internal combustion engine is sequentially connected to a hydrogen selective catalytic reducer, a hydrogen oxidation catalyst and an ammonia selective catalytic reducer; 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.

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

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

[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 a control unit ECU.

[0008] According to a second aspect of the present invention, there is provided a H 2 The control method of the internal combustion engine aftertreatment system comprises the following steps: S1, judging whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst is greater than a preset temperature T 1 If yes, execute S2, if no, execute S3; S2, determine whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction device is greater than the preset temperature T 2 And is less than the preset temperature T 3 If so, execute S4. If the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction device is less than or equal to the preset temperature T 2 , then execute S5; S3, control H 2 The internal combustion engine burns in normal combustion mode; S4, control H 2 Internal combustion engine high H 2 The original combustion mode is burning; S5, control H 2 The internal combustion engine maintains combustion in normal combustion mode.

[0009] In some embodiments of the present invention, the high H 2 The original combustion mode adopts a significantly delayed ignition advance angle and increased H 2 The injection volume and H 2 Secondary injection is achieved in one or more ways.

[0010] In some embodiments of the present invention, the preset temperature T 1 According to the hydrogen oxidation catalyst 2 The conversion capability setting.

[0011] In some embodiments of the present invention, the H 2 After the 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 T 4 , if so, the urea nozzle is controlled to start.

[0012] According to a third aspect of the present invention, there is provided a mechanical device, comprising the above-mentioned H 2 Internal combustion engine aftertreatment system.

[0013] The present application embodiment provides a H 2 Internal combustion engine aftertreatment system, the H 2Internal combustion engine aftertreatment system combined with H 2 The emission characteristics of internal combustion engines make full use of the H generated by incomplete combustion in the exhaust gas. 2 As a reducing agent, it converts part of the harmful NOx in the exhaust gas, not only reducing NH 3 -Urea consumption in SCR also causes H 2 -SCR is placed at the front end, effectively utilizing the temperature in the exhaust gas to improve the low-temperature NOx conversion efficiency. 2 -The existence of SCR and HOC avoids H 2 The damage to the NOx sensor improves the reliability of the NOx sensor and 2 The control of the original internal combustion engine uses the H 2 Pollutant emissions can be reduced without introducing new equipment, effectively reducing system complexity and lowering costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0015] Figure 1 The present invention 2 Schematic diagram of the overall structure of the internal combustion engine aftertreatment system;

[0016] Figure 2 The present invention 2 Flow chart of a control method for an internal combustion engine aftertreatment system.

[0017] The reference numerals in the accompanying drawings represent as follows: 1. third temperature sensor; 2. hydrogen selective catalytic reducer; 3. hydrogen oxidation catalyst; 4. ammonia selective catalytic reducer; 5. nitrogen oxide sensor; 6. first temperature sensor; 7. urea nozzle; 8. control unit ECU; 9. second temperature sensor. DETAILED DESCRIPTION

[0018] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0019] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0020] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. 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. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0021] The present application embodiment discloses a H 2 Internal combustion engine aftertreatment system. Figure 1 As shown, H 2 The internal combustion engine aftertreatment system includes 2 The exhaust gas of the internal combustion engine is sequentially connected to the hydrogen selective catalytic reduction device 2 (H 2 -SCR), hydrogen oxidation catalyst 3 (HOC) and ammonia selective catalytic reduction 4 (NH 3 -SCR); wherein, a urea nozzle 7 is provided between the ammonia selective catalytic reducer 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 H in this technical solution 2 Internal combustion engine aftertreatment system, H 2The internal combustion engine generates exhaust gas, which first enters the hydrogen selective catalytic reducer 2. The hydrogen selective catalytic reducer 2 catalyzes the hydrogen in the exhaust gas to reduce nitrogen oxides, so that the hydrogen and nitrogen oxides in the exhaust gas react, which can reduce the content of hydrogen and nitrogen oxides in the exhaust gas at the same time. Then the exhaust gas continues to enter the hydrogen oxidation catalyst 3. The hydrogen oxidation catalyst 3 catalyzes the oxidation reaction of hydrogen and oxygen to further reduce the content of hydrogen in the exhaust gas, so that the hydrogen content of the exhaust gas entering the ammonia selective catalytic reducer 4 is greatly reduced, effectively reducing or even eliminating the influence of hydrogen on the ammonia selective catalytic reducer 4, and protecting the nitrogen oxide sensor 5. The nitrogen oxides that have not reacted completely in the exhaust gas will be measured by the nitrogen oxide sensor 5 to obtain the concentration, and through the perception of the first temperature sensor 6, urea is injected within a suitable temperature range to obtain the urea required to consume the nitrogen oxides. This part of the urea is hydrolyzed into NH 3 The nitrogen oxides react with the ammonia selective catalytic reducer 4, thereby the present invention not only effectively reduces the nitrogen oxide emissions and hydrogen emissions, but also effectively reduces the urea consumption, ensuring the effect of the nitrogen oxide sensor 5 on the detection of nitrogen oxides.

[0023] In addition, the present invention places the hydrogen selective catalytic reducer 2 upstream of the hydrogen oxidation catalyst 3, so that during cold start, the ammonia selective catalytic reducer 4 is closer to the hydrogen oxidation catalyst 3. 2 When the temperature of the internal combustion engine is lowered due to the distance, it is not conducive to the conversion of NOx by the ammonia selective catalytic reducer 4. Based on the fact that the hydrogen selective catalytic reducer 2 has a higher conversion efficiency than the ammonia selective catalytic reducer 4 under low temperature conditions, the hydrogen conversion efficiency under cold start conditions can be improved. 2 The conversion effect of the internal combustion engine aftertreatment system on NOx effectively reduces the pollutant content of the exhaust gas finally emitted during cold start.

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

[0025] According to the conversion capacity of the hydrogen oxidation catalyst 3 to hydrogen, 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 conversion efficiency for hydrogen, and even if a large amount of hydrogen appears in front of the hydrogen oxidation catalyst 3, it can be oxidized. 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 conversion efficiency for hydrogen and cannot process a large amount of hydrogen. Based on this, the H 2 The combustion mode of the internal combustion engine determines whether to choose normal combustion mode or high H 2The original combustion mode is used to control the hydrogen content in the exhaust gas, so that when the hydrogen oxidation catalyst 3 has a higher conversion efficiency for hydrogen, the hydrogen content in the exhaust gas is increased, and when the hydrogen oxidation catalyst 3 has a lower conversion efficiency for hydrogen, the hydrogen content in the exhaust gas is avoided to be too high.

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

[0027] In the present invention, since the NOx conversion efficiency of the hydrogen selective catalytic reducer 2 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 under low temperature conditions, and the conversion efficiency of the high-temperature hydrogen selective catalytic reducer 2 is much lower than that of the ammonia selective catalytic reducer 4, it is necessary to fully utilize the conversion efficiency of the hydrogen selective catalytic reducer 2 at low temperatures, and use the ammonia selective catalytic reducer 4 at high temperatures.

[0028] The temperature of the exhaust gas entering the hydrogen selective catalytic reducer 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 hydrogen selective catalytic reducer 2 exceeds the set temperature. If so, it indicates that the hydrogen selective catalytic reducer 2 has a high conversion efficiency for hydrogen, and the H 2 Internal combustion engine with high H 2 The original combustion mode is burning. Otherwise, it indicates that the hydrogen selective catalytic reducer 2 has a low conversion efficiency for hydrogen, and it is possible to continue to maintain H 2 The internal combustion engine burns in normal combustion mode, burning as completely as possible and making full use of H 2 -SCR has high low temperature conversion efficiency, making H 2 Reacts with NOx in exhaust gas pollutants to improve conversion efficiency, reduce the hydrogen content in the original exhaust, and avoid safety and reliability risks caused by excessive hydrogen discharge.

[0029] In some embodiments of the present invention, 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 the signals of 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 nozzle 7, H 2 Internal combustion engines, etc., to achieve urea injection and H 2 Regulation of combustion mode of internal combustion engines.

[0031] In some embodiments of the present invention, the hydrogen selective catalytic reducer 2 is a modified selective catalytic reduction system, which can better exert the reducing properties of hydrogen and improve the conversion efficiency of hydrogen and nitrogen oxides in the selective catalytic reduction system, thereby fully utilizing the reaction of hydrogen and nitrogen oxides in the exhaust gas and reducing the content of hydrogen and nitrogen oxides in the exhaust gas.

[0032] This embodiment also proposes a H 2 Control method of aftertreatment system of internal combustion engine, such as Figure 2 As shown, the control method includes the following steps:

[0033] S0, first confirm that the hydrogen oxidation catalyst 3 is 2 conversion capacity.

[0034] S1. Determine whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is greater than the preset temperature T 1 If yes, execute S2, if no, execute S3.

[0035] In the present invention, the preset temperature T 1 According to the hydrogen oxidation catalyst 3 2 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 T 1 , indicating that the hydrogen oxidation catalyst 3 has a higher conversion efficiency for hydrogen, otherwise, the hydrogen oxidation catalyst 3 has a lower conversion efficiency for hydrogen.

[0036] S2, judging whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reducer 2 is greater than the preset temperature T 2 And is less than the preset temperature T 3 If yes, then execute S4. If the temperature of the exhaust gas upstream of the hydrogen selective catalytic reducer 2 is less than or equal to the preset temperature T 2 , then execute S5.

[0037] In the present invention, the preset temperature T 2 and preset temperature T 3 Through experimental calibration, it should be understood that when the temperature of the exhaust gas upstream of the hydrogen selective catalytic reducer 2 is greater than the preset temperature T 2 And is less than the preset temperature T 3 When the temperature of the exhaust gas upstream of the hydrogen selective catalytic reducer 2 is lower than the preset temperature T 2 , the hydrogen selective catalytic reducer 2 has a lower catalytic reaction efficiency for hydrogen and nitrogen oxides.

[0038] S3, control H 2 The internal combustion engine burns 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 T 1 At this time, the hydrogen oxidation catalyst 3 has a low conversion efficiency for hydrogen and cannot process a large amount of H 2 , by controlling H 2 The internal combustion engine burns in normal combustion mode, which can avoid a large amount of H in the exhaust gas. 2 The generated hydrogen is thereby ensured to have a percentage of hydrogen treatment by the hydrogen selective catalytic reducer 2 and the hydrogen oxidation catalyst 3 , and the amount of hydrogen passing through the nitrogen oxide sensor 5 and entering the ammonia selective catalytic reducer 4 is reduced.

[0040] In some embodiments of the present invention, H 2 After the internal combustion engine enters the normal combustion mode, it is determined whether the temperature of the exhaust gas upstream of the urea nozzle 7 reaches the preset temperature T 4 If yes, the urea nozzle 7 is controlled to start; the preset temperature T 4 It can be set according to the optimal temperature range of urea injection, such as setting the preset temperature T 4 Set to 180°C.

[0041] S4. Control H 2 Internal combustion engine high H 2 The original combustion mode is burning.

[0042] Since the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst 3 is greater than the preset temperature T 1 At this time, the hydrogen oxidation catalyst 3 has a higher conversion efficiency for hydrogen, and it can process a large amount of H 2 , by controlling H 2 Internal combustion engine at high H 2 The original combustion mode is used for combustion. In this mode, H 2 Internal combustion engine combustion control to improve the H 2 content.

[0043] In some embodiments of the present invention, high H 2 The original combustion mode can be achieved by significantly delaying the ignition advance angle and increasing the concentration of H 2 The injection volume and H 2 It is achieved by one or more of the following methods: secondary injection.

[0044] S5. Control H 2 The internal combustion engine maintains combustion in normal combustion mode.

[0045] At this time, although the hydrogen oxidation catalyst 3 has a high conversion efficiency for hydrogen, the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction device 2 is less than or equal to the preset temperature T 2The hydrogen selective catalytic reducer 2 has a low catalytic reaction efficiency for hydrogen and nitrogen oxides. 2 The internal combustion engine maintains normal combustion mode and burns as fully as possible, which can reduce the H in the original exhaust. 2 ingredients, avoid excessive H 2 Eliminate risks to safety, reliability, etc.

[0046] This embodiment also provides a mechanical device, which includes the above-mentioned H 2 Internal combustion engine aftertreatment system, the mechanical equipment includes but is not limited to agricultural machinery, construction machinery, passenger vehicles, etc.

[0047] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A H2 internal combustion engine aftertreatment system, characterized in that: It includes a hydrogen selective catalytic reducer, a hydrogen oxidation catalyst and an ammonia selective catalytic reducer which are sequentially connected to the tail gas of the H2 internal combustion engine; A urea nozzle is provided between the ammonia selective catalytic reducer 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.

2. The H2 internal combustion engine aftertreatment system according to claim 1, characterized in that: A second temperature sensor is provided between the hydrogen oxidation catalyst and the hydrogen selective catalytic reducer.

3. The H2 internal combustion engine aftertreatment system according to claim 2, characterized in that: A third temperature sensor is provided on one side of the air inlet of the hydrogen selective catalytic reducer.

4. The H2 internal combustion engine aftertreatment system according to claim 3, characterized in that: The urea nozzle, the nitrogen oxide sensor, the first temperature sensor, the second temperature sensor and the third temperature sensor are connected to a control unit ECU.

5. A control method for an H2 internal combustion engine aftertreatment system according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, determining whether the temperature of the exhaust gas upstream of the hydrogen oxidation catalyst is greater than a preset temperature T1, if so, executing S2, if not, executing S3; S2, judging whether the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction device is greater than a preset temperature T2 and less than a preset temperature T3, if so, executing S4, if the temperature of the exhaust gas upstream of the hydrogen selective catalytic reduction device is less than or equal to the preset temperature T2, executing S5; S3, controlling the H2 internal combustion engine to burn in a normal combustion mode; S4, controlling the combustion mode of the H2 internal combustion engine with high H2 original exhaust; S5. Control the H2 internal combustion engine to maintain combustion in a normal combustion mode.

6. The control method according to claim 5, characterized in that: The high H2 primary exhaust combustion mode combustion is achieved by one or more of significantly delaying the ignition advance angle, increasing the injection amount of rich H2, and H2 secondary injection.

7. The control method according to claim 5, characterized in that: The preset temperature T1 is set according to the conversion capacity of the hydrogen oxidation catalyst to H2.

8. The control method according to claim 5, characterized in that: 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 a preset temperature T4. If so, the urea nozzle is controlled to start.

9. A mechanical device, characterized in that: It comprises an H2 internal combustion engine aftertreatment system as described in any one of claims 1-4.

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