An ammonia fuelled internal combustion engine aftertreatment system and control method

Abstract

The application discloses an ammonia fuel internal combustion engine aftertreatment system and a control method. The ammonia fuel internal combustion engine aftertreatment system comprises an ammonia tank, an internal combustion engine, a front-stage selective catalytic reducer, an oxidation catalyst, a rear-stage selective catalytic reducer and an integrated processor. A first ammonia nozzle of the ammonia tank is communicated with the internal combustion engine. A front-stage nitrogen oxide sensor, a first temperature sensor, a second temperature sensor and a rear-stage nitrogen oxide sensor are arranged on a pipeline between the front-stage selective catalytic reducer, the oxidation catalyst, the rear-stage selective catalytic reducer and the integrated processor. A heater of the integrated processor is arranged outside a particle trap. An internal part of the particle trap forms a tail gas flow channel. A side wall of the tail gas flow channel is coated with an ammonia escape catalyst. The ammonia fuel internal combustion engine aftertreatment system can solve the problem of high pollutant emission level of an ammonia internal combustion engine, and realize ultra-low emission of pollutants. x ​

Description

TECHNICAL FIELD

[0001] The application relates to the field of engine exhaust treatment, in particular to an ammonia fuel internal combustion engine aftertreatment system and a control method. BACKGROUND

[0002] The ammonia internal combustion engine uses ammonia gas as fuel, and compared with fuels such as diesel and gasoline, the ammonia fuel composition does not contain carbon elements, and theoretically will not cause carbon dioxide emissions, and is a zero-carbon fuel that can reduce the greenhouse effect. However, the level of other harmful pollutants (such as original engine ammonia NH3, NO x , N2O) emitted by the ammonia internal combustion engine is high, and low emission of pollutants cannot be achieved. The current ammonia fuel engine aftertreatment system has the disadvantages of complex structure, high manufacturing cost, low safety, and cannot effectively treat various pollutants. SUMMARY

[0003] The application discloses an ammonia fuel internal combustion engine aftertreatment system and a control method, which can solve the problem of high emission level of pollutants such as original engine ammonia NH3, NO x of the ammonia internal combustion engine, and achieve ultra-low emission of pollutants.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0005] In a first aspect, the application provides an ammonia fuel internal combustion engine aftertreatment system, comprising an ammonia tank, an internal combustion engine, a front-stage selective catalytic reducer, an oxidation catalyst, a rear-stage selective catalytic reducer and an integrated processor arranged in sequence.

[0006] The ammonia tank comprises a first ammonia nozzle, and the first ammonia nozzle is in communication with the internal combustion engine.

[0007] A front-stage nitrogen oxide sensor and a first temperature sensor are arranged on a pipeline between the oxidation catalyst and the rear-stage selective catalytic reducer, a second temperature sensor is arranged on a pipeline between the rear-stage selective catalytic reducer and the integrated processor, and a rear-stage nitrogen oxide sensor is arranged on a pipeline away from the internal combustion engine side of the integrated processor.

[0008] The integrated processor comprises a particle trap and a heater, the heater is sleeved outside the particle trap, an exhaust gas flow passage is formed in the inside of the particle trap, and the side wall of the exhaust gas flow passage is coated with an ammonia escape catalyst.

[0009] The ammonia fuel internal combustion engine aftertreatment system sequentially arranges the front-stage selective catalytic reducer, the oxidation catalyst, the rear-stage selective catalytic reducer and the integrated processor on the exhaust gas pipeline, and realizes the treatment of NH3, NO xand HC purification, as well as NH3, and NO generated in the post-treatment system x The purification of ammonia NH3 and NO in ammonia internal combustion engine x The problem of high emission levels is solved by achieving ultra-low emissions of pollutants, and the heater in the integrated processor solves the problem of particulate filter regeneration.

[0010] Specifically, the ammonia tank of the present application injects ammonia into the internal combustion engine through the first ammonia nozzle, and the combustion of ammonia causes the internal combustion engine to output power for driving or other operations. During the combustion of ammonia, a certain amount of NH3 and NO x The post-treatment system of this application is used to purify the NH3 and NO emitted by the ammonia internal combustion engine. x Oxidation-reduction reaction occurs to realize NH3 and NO x The initial purification is then carried out through the oxidation catalyst to further purify the NH3 and HC emitted by the original engine (produced by auxiliary ignition materials such as diesel and gasoline). The NH3 and NO generated in the post-treatment system are then purified by the post-stage selective catalytic reduction device. x Further purification is achieved. Finally, the particulate matter in the exhaust is filtered by the particulate filter within the integrated processor, and excess NH3 is finally purified by an ammonia slip catalyst located on the sidewalls of the exhaust gas flow channel within the particulate filter. A heater is installed on the exterior of the particulate filter to maintain a high internal temperature, facilitating the reaction between carbon particles and oxygen, enabling active regeneration of the particulate filter. Furthermore, a pre-stage NOx sensor, a first temperature sensor, a second temperature sensor, and a post-stage NOx sensor are located in various locations within the aftertreatment system to monitor the system's operating status in real time and facilitate appropriate action.

[0011] In some embodiments, the ammonia tank further includes a second ammonia nozzle, which is connected to a first connection position; wherein the first connection position is any position of the pipeline between the oxidation catalyst and the post-stage selective catalytic reduction device.

[0012] In some embodiments, the ammonia fuel internal combustion engine aftertreatment system also includes a processor, which is connected to the front-stage nitrogen oxide sensor, the first temperature sensor, the second temperature sensor and the rear-stage nitrogen oxide sensor signal, and is used to adjust the injection amount of the second ammonia nozzle according to the temperature detected by the first temperature sensor and the second temperature sensor, and the nitrogen oxide concentration detected by the front-stage nitrogen oxide sensor and the rear-stage nitrogen oxide sensor.

[0013] In some embodiments, the ammonia fuel internal combustion engine aftertreatment system further comprises a dinitrogen monoxide processor, which is arranged on the pipeline away from the internal combustion engine on the side of the integrated processor.

[0014] In some embodiments, the ammonia fuel internal combustion engine aftertreatment system further comprises a differential pressure sensor, one end of which is in communication with a second connection position, and the other end of which is in communication with a third connection position; wherein the second connection position is any position of the pipeline between the post-stage selective catalytic reducer and the integrated processor, and the third connection position is any position of the pipeline between the integrated processor and the dinitrogen monoxide processor.

[0015] The processor is in signal connection with the differential pressure sensor, and is configured to control the start and stop of the heater according to the pressure difference detected by the differential pressure sensor.

[0016] In some embodiments, a third temperature sensor and an alarm are further arranged on the pipeline between the integrated processor and the dinitrogen monoxide processor.

[0017] The processor is in signal connection with the third temperature sensor and the alarm, and is configured to monitor the working state of the heater according to the temperature detected by the third temperature sensor in the state that the heater is started, so as to control the alarm to issue an alarm.

[0018] In a second aspect, the present application provides a control method of an ammonia fuel internal combustion engine aftertreatment system, which comprises:

[0019] A first temperature t1 and a second temperature t2 are obtained through a first temperature sensor and a second temperature sensor, and a first concentration c1 and a second concentration c2 are obtained through a front-stage nitrogen oxide sensor and a post-stage nitrogen oxide sensor.

[0020] The first temperature t1 is compared with a preset first temperature limit value T1, the first concentration c1 is compared with a preset first concentration limit value C1 and a second concentration limit value C2, and the second concentration c2 is compared with a preset second concentration limit value C2 and a third concentration limit value C3; wherein C1>C2>C3.

[0021] If t1>T1, the first ammonia gas nozzle is controlled to be closed.

[0022] If t1≤T1 and c1>C1, the first ammonia gas nozzle is controlled to be closed.

[0023] If t1≤T1 and c1≤C1 and c2C2, the first ammonia gas nozzle is controlled to be opened and sprayed at a preset spraying amount.

[0024] If t1≤T1 and c1≤C1, C2≤c2≤C1, control the first ammonia nozzle to open and spray at a preset spray amount.

[0025] In some embodiments, the control method further comprises:

[0026] If t1>T1, control the second ammonia nozzle to close;

[0027] If t1≤T1 and c1>C1, control the second ammonia nozzle to close;

[0028] If t1≤T1 and c1≤C1, c2

[0029] If t1≤T1 and c1≤C1, C2≤c2≤C1, control the second ammonia nozzle to open and spray at a spray amount calculated based on a preset rule; the preset rule comprises calculating the spray amount according to the conversion efficiency of the rear-stage selective catalytic reducer.

[0030] In some embodiments, after the control of the second ammonia nozzle to open and spray at a spray amount calculated based on a preset rule, the control method further comprises:

[0031] Continuously monitor the second concentration c2 of the rear-stage nitrogen oxide sensor;

[0032] If c2≤C3, control the spray amounts of the first ammonia nozzle and the second ammonia nozzle to remain unchanged;

[0033] If c2>C3, control the first ammonia nozzle and the second ammonia nozzle to close.

[0034] In some embodiments, the control method further comprises:

[0035] Obtain a pressure difference value p through a pressure difference sensor;

[0036] Compare the pressure difference value p with preset first pressure difference limit value P1 and second pressure difference limit value P2;

[0037] If p

[0038] If p>P2, control the heater to open and operate at a first power;

[0039] If P1≤p≤P2 and the concentration of N2O is lower than a preset concentration, control the heater to close;

[0040] If P1≤p≤P2 and the concentration of N2O is higher than a preset concentration, control the heater to open and operate at a second power.

[0041] In some embodiments, when the heater is open, the control method further comprises:

[0042] acquire a third temperature t3 through a third temperature sensor;

[0043] compare the third temperature t3 with preset second temperature limit T2, third temperature limit T3 and fourth temperature limit T4;

[0044] when p>P2, if T3≤t3≤T4, control the heater to open and run at the first power; if t3

[0045] when P1≤p≤P2, and the concentration of N2O is higher than the preset concentration, if T2≤t3≤T4, control the heater to open and run at the second power; if t3 BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 a structure schematic diagram of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0047] Figure 2 a flowchart of a control method of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0048] Figure 3 a flowchart of a control method of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0049] Figure 4 a flowchart of a control method of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0050] Figure 5 a flowchart of a control method of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0051] Figure 6 a flowchart of a control method of an ammonia fuel internal combustion engine aftertreatment system provided by an embodiment of the present application;

[0052] Figure: 1, ammonia tank; 2, internal combustion engine; 3, front-stage selective catalytic reducer; 4, oxidation catalytic converter; 5, rear-stage selective catalytic reducer; 6, integrated processor; 61, particulate trap; 62, heater; 7, front-stage nitrogen oxide sensor; 8, first temperature sensor; 9, second temperature sensor; 10, rear-stage nitrogen oxide sensor; A, first ammonia nozzle; B, second ammonia nozzle; p, first connection position; 11, nitrous oxide processor; 12, differential pressure sensor; m, second connection position; n, third connection position; 13, third temperature sensor. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; the "and / or" in the text only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0054] The terms "first", "second" are only used for description purposes, and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" is two or more than two.

[0055] In a first aspect, as shown in the drawings, the present application provides an ammonia fuel internal combustion engine aftertreatment system, comprising an ammonia tank 1, an internal combustion engine 2, a front selective catalytic reducer 3, an oxidation catalyst 4, a rear selective catalytic reducer 5 and an integrated processor 6 arranged in sequence; Figure 1

[0056] The ammonia tank 1 comprises a first ammonia nozzle A, and the first ammonia nozzle A is communicated with the internal combustion engine 2.

[0057] A front nitrogen oxide sensor 7 and a first temperature sensor 8 are arranged on the pipeline between the oxidation catalyst 4 and the rear selective catalytic reducer 5, a second temperature sensor 9 is arranged on the pipeline between the rear selective catalytic reducer 5 and the integrated processor 6, and a rear nitrogen oxide sensor 10 is arranged on the pipeline away from the internal combustion engine 2 of the integrated processor 6.

[0058] The integrated processor 6 comprises a particle trap 61 and a heater 62, the heater 62 is sleeved outside the particle trap 61, an exhaust gas flow passage is formed in the inside of the particle trap 61, and the side wall of the exhaust gas flow passage is coated with an ammonia escape catalyst.

[0059] The ammonia fuel internal combustion engine aftertreatment system realizes the reduction of NH3, NOx and PM in the original ammonia internal combustion engine exhaust by arranging the front selective catalytic reducer 3, the oxidation catalyst 4, the rear selective catalytic reducer 5 and the integrated processor 6 in sequence on the exhaust pipeline. x ​and HC purification, as well as NH3, and NO generated in the post-treatment system x The purification of ammonia NH3 and NO in ammonia internal combustion engine x The problem of high emission levels is solved by achieving ultra-low emissions of pollutants, and the heater in the integrated processor solves the problem of particulate filter regeneration.

[0060] Specifically, the ammonia tank 1 of the present application injects ammonia into the internal combustion engine 2 through the first ammonia nozzle A. The combustion of ammonia causes the internal combustion engine 2 to output power for driving or other operations. During the combustion of ammonia, a certain amount of NH3 and NO x and HC and other harmful pollutants, which need to be purified through the post-treatment system to convert the pollutants into non-toxic and harmless substances and discharge them to achieve low emissions.

[0061] The exhaust gas containing various pollutants generated by the ammonia fuel internal combustion engine 2 first flows into the front-stage selective catalytic reduction device 3, so that the NH3 and NO originally emitted by the ammonia fuel internal combustion engine 2 are reduced. x A passive redox reaction occurs to achieve NH3 and NO x The main product of this process is harmless N2, which also contains a certain amount of N2O.

[0062] Next, since the ammonia internal combustion engine 2 has excessive NH3 emissions under most operating conditions, the remaining NH3 needs to be further oxidized by the oxidation catalyst 4 (the main product of this process is harmless N2, and also contains a certain amount of by-products N2O and NO x Since ammonia fuel usually needs to be ignited by auxiliary fuel such as diesel and gasoline, the oxidation catalyst 4 can also purify HC that may be present in the exhaust gas.

[0063] Afterwards, the exhaust gas continues to flow into the post-stage selective catalytic reduction device 5, so that the incompletely oxidized NH3 and NO x Further redox reaction occurs to generate harmless N2, achieving NO x Further purification.

[0064] Finally, the exhaust continues to flow into the integrated processor 6, where the particulate matter (such as carbon particles from auxiliary fuels such as diesel and gasoline) entrained in the exhaust is filtered by the particulate filter 61. The ammonia slip catalyst coating on the sidewalls of the exhaust gas flow channel within the particulate filter 61 provides a final purification of excess NH3. A heater 62 is mounted on the exterior of the particulate filter 61 to maintain a high internal temperature, heating the airflow and facilitating the reaction of excess carbon particles with oxygen, thus achieving active regeneration of the particulate filter 61. Furthermore, a pre-stage NOx sensor 7, a first temperature sensor 8, a second temperature sensor 9, and a post-stage NOx sensor 10 are located in various locations within the aftertreatment system to monitor relevant parameters of the aftertreatment system in real time, thus providing the system with essential functions such as emission monitoring, status monitoring, state switching, and fault reporting.

[0065] In some embodiments, the ammonia tank 1 further includes a second ammonia nozzle B, which is connected to the first connection position p; wherein the first connection position p is any position of the pipeline between the oxidation catalyst 4 and the post-stage selective catalytic reduction device 5.

[0066] In one possible implementation, under a few operating conditions, the NO in the exhaust gas x The concentration is high and the NH3 concentration is insufficient, so that the exhaust gas still contains some NO after passing through the post-stage selective catalytic reduction device 5. x In order to solve the above problem, the present invention adds a second ammonia nozzle B, which can supplement and purify NO x Required NH3. Figure 1 As shown, the second ammonia nozzle B of the ammonia tank 1 is connected to the pipeline between the oxidation catalyst 4 and the post-stage selective catalytic reduction device 5. When the post-stage nitrogen oxide sensor 10 detects that the concentration of nitrogen oxides is not within the preset range, NH3 can be supplemented through the second ammonia nozzle B for use in the post-stage selective catalytic reduction device 5 to further purify NO x It should be noted that the current selective catalytic reduction device uses urea aqueous solution as a reducing agent, specifically firstly thermally decomposes urea to generate NH3 and CO2, and then reacts NH3 with NO x The reaction generates non-toxic water and nitrogen. The present invention directly uses NH3 instead of urea, which reduces the decomposition steps of urea, simplifies the reaction process and reduces costs.

[0067] In some embodiments, the ammonia fuel internal combustion engine after-treatment system also includes a processor (not shown in the figure), which is signal-connected to the front-stage nitrogen oxide sensor 7, the first temperature sensor 8, the second temperature sensor 9 and the rear-stage nitrogen oxide sensor 10, and is used to adjust the injection amount of the second ammonia nozzle B according to the temperature detected by the first temperature sensor 8 and the second temperature sensor 9, and the nitrogen oxide concentration detected by the front-stage nitrogen oxide sensor 7 and the rear-stage nitrogen oxide sensor 10.

[0068] One possible implementation method is Figure 1 As shown, based on the monitoring results of the first temperature sensor 8, the second temperature sensor 9, the front-stage NOx sensor 7, and the rear-stage NOx sensor 10, the processor can control whether the second ammonia nozzle B needs to inject and adjust the injection amount of the second ammonia nozzle B to achieve exhaust gas purification. It should be noted that based on the monitoring results, when both the temperature and NOx concentration are outside the preset range, the processor can also control the first ammonia nozzle A and the second ammonia nozzle B to shut down, stopping the ammonia-fueled internal combustion engine to facilitate troubleshooting.

[0069] In some embodiments, the ammonia fuel internal combustion engine aftertreatment system further includes a nitrous oxide processor 11 , which is disposed on a pipeline on a side of the integrated processor 6 away from the internal combustion engine 2 .

[0070] One possible implementation method is Figure 1 As shown, in order to purify the N2O generated by the original machine and the N2O generated in the after-treatment system, the present application provides a nitrous oxide processor 11 to achieve the purification of N2O in the exhaust gas. Since the chemical properties of N2O are relatively stable, its catalytic purification requires a higher temperature. The heater 62 of the present application can heat the exhaust gas flow so as to provide the required temperature for the purification of N2O when the nitrous oxide processor 11 is working, thereby improving the conversion efficiency. It should be noted that in another possible implementation method, since the emission regulations that the relevant ammonia internal combustion engine products need to comply with are China Road Stage VI / European Road Stage VI / China Non-Road Stage IV, there are no requirements for N2O emission levels in these regulations, so the nitrous oxide processor 11 may not be provided.

[0071] In some embodiments, the ammonia fuel internal combustion engine aftertreatment system further includes a differential pressure sensor 12, one end of the differential pressure sensor 12 is connected to the second connection position m, and the other end is connected to the third connection position n; wherein the second connection position m is any position of the pipeline between the post-stage selective catalytic reduction device 5 and the integrated processor 6, and the third connection position n is any position of the pipeline between the integrated processor 6 and the nitrous oxide processor 11;

[0072] The processor is in signal connection with the differential pressure sensor 12, and is configured to control the start and stop of the heater 62 according to the pressure difference detected by the differential pressure sensor 12.

[0073] In a possible implementation manner, as shown in Figure 1 , the application can monitor the working state of the particulate trap 61 in real time by arranging the differential pressure sensors 12 on both sides of the integrated processor 6. When the pressure difference on both sides of the particulate trap 61 is low, the burn-through phenomenon of the particulate trap 61 may occur, and the processor needs to control the aftertreatment system to stop working for maintenance. When the pressure difference on both sides of the particulate trap 61 is high, it indicates that too many carbon particles are deposited, and the processor needs to control the heater 62 to open to promote the reaction of the carbon particles with NO2 or O2, so as to regenerate the particulate trap 61 and improve the tail gas purification efficiency.

[0074] In some embodiments, a third temperature sensor 13 and an alarm (not shown in the figure) are further arranged on the pipeline between the integrated processor 6 and the nitrous oxide processor 11;

[0075] The processor is in signal connection with the third temperature sensor 13 and the alarm, and is configured to monitor the working state of the heater 62 according to the temperature detected by the third temperature sensor 13 in the start state of the heater 62, so as to control the alarm to issue an alarm.

[0076] In a possible implementation manner, as shown in Figure 1 , the rear end of the integrated processor 6 is further provided with the third temperature sensor 13, and the temperature of the gas flow can be monitored in real time by the third temperature sensor 13 in the open state of the heater 62, so as to monitor whether the heater 62 works normally. When it is detected that the temperature is not in the preset range, the processor needs to control the heater to close and make the alarm issue a fault alarm.

[0077] In a second aspect, the application provides a control method of an ammonia fuel internal combustion engine aftertreatment system, as shown in Figure 2 , the control method comprises the following steps.

[0078] S201, acquiring a first temperature t1 and a second temperature t2 by the first temperature sensor and the second temperature sensor, and acquiring a first concentration c1 and a second concentration c2 by the front-stage nitrogen oxide sensor and the rear-stage nitrogen oxide sensor;

[0079] S202, comparing the first temperature t1 with a preset first temperature limit T1, comparing the first concentration c1 with a preset first concentration limit C1 and a second concentration limit C2, and comparing the second concentration c2 with a preset second concentration limit C2 and a third concentration limit C3; wherein C1>C2>C3;

[0080] S203, if t1>T1, controlling the first ammonia gas nozzle to close;

[0081] If t1≤T1 and c1>C1, control the first ammonia nozzle to be closed;

[0082] If t1≤T1 and c1≤C1 and c2

[0083] If t1≤T1 and c1≤C1 and C2≤c2≤C1, control the first ammonia nozzle to be opened and sprayed according to the preset spraying amount.

[0084] In the above S203, the steps further include:

[0085] If t1>T1, control the second ammonia nozzle to be closed;

[0086] If t1≤T1 and c1>C1, control the second ammonia nozzle to be closed;

[0087] If t1≤T1 and c1≤C1 and c2

[0088] If t1≤T1 and c1≤C1 and C2≤c2≤C1, control the second ammonia nozzle to be opened and sprayed according to the spraying amount calculated based on the preset rule; the preset rule includes calculating the spraying amount according to the conversion efficiency of the rear selective catalytic reducer.

[0089] In one possible implementation manner, in combination with Figure 1 The control method of the ammonia fuel internal combustion engine aftertreatment system specifically includes the following steps:

[0090] (1) When the ammonia fuel internal combustion engine 2 starts to operate, first, the value of the first temperature t1 of the first temperature sensor 8 needs to be read. If the first temperature t1 is higher than the first temperature limit value T1, it indicates that the HC, NH3 and other combustible materials emitted by the original engine of the internal combustion engine 2 are too much. These substances do not burn normally and sufficiently in the internal combustion engine 2, but migrate to the oxidation catalyst 4 to occur oxidation exothermic reaction, resulting in that the first temperature sensor 8 monitors a too high temperature value. Therefore, at this time, the internal combustion engine 2 should be controlled to limit the speed and torque to prevent accidents, and an alarm is prompted to the related fault, and if necessary, the internal combustion engine 2 and the aftertreatment system can also be controlled to stop working.

[0091] (2) In the case that the temperature value of the first temperature sensor 8 is not higher than the first temperature limit value T1, further judgment is made based on the nitrogen oxide concentration data measured by the front nitrogen oxide sensor 7. If the first concentration c1 measured by the front nitrogen oxide sensor 7 is higher than the first concentration limit value C1, it indicates that at this time, the front selective catalytic reducer 3 has a fault, resulting in that the NOx in the front selective catalytic reducer 3 cannot be converted normally, and the concentration of the NOx in the front selective catalytic reducer 3 is too high. Therefore, at this time, the ammonia fuel internal combustion engine 2 should be controlled to limit the speed and torque to prevent accidents, and an alarm is prompted to the related fault, and if necessary, the internal combustion engine 2 and the aftertreatment system can also be controlled to stop working. xIf the NH3 is not fully reacted, the engine 2 should be controlled to limit the speed and torque to prevent the emission from exceeding the standard, and an alarm should be given to indicate the related failure. If necessary, the engine 2 and the aftertreatment system should be stopped.

[0092] (3) If the measured value of the upstream NOx sensor 7 is not higher than the first concentration limit C1, the measured second concentration c2 of the downstream NOx sensor 10 is further investigated. If the second concentration c2 is lower than the second concentration limit C2, it indicates that the NO x If the NH3 and NOx emissions are both low, no additional ammonia injection through the second ammonia nozzle B is needed, and the monitoring should be continued.

[0093] (4) If the first concentration c1 measured by the upstream NOx sensor 7 is between the first concentration limit C1 and the second concentration limit C2, it indicates that there is still a certain concentration of NO x in the exhaust gas. The second ammonia nozzle B should be opened, and the specific ammonia injection amount can be calculated according to the injection strategy based on the conversion efficiency closed loop of the downstream SCR 5 or the ammonia storage closed loop of the downstream SCR 5. At this time, the average temperature is taken as the average of the first temperature t1 and the second temperature t2, and ammonia is injected through the second ammonia nozzle B according to the calculated injection amount, while the monitoring is continued.

[0094] It should be noted that, due to the cross-sensitivity of the NOx sensor commonly used in the engine 2 industry (i.e. NH3 is oxidized to NO inside the sensor, which is then recognized as NO x by the sensor), the values measured by the upstream NOx sensor 7 and the downstream NOx sensor 10 are actually approximately equal to the sum of the NO x and NH3 concentrations in the measured gas flow.

[0095] In some embodiments, as shown in Figure 3 , the second ammonia nozzle is controlled to be opened and injected at the injection amount calculated based on the preset rule, and then further includes:

[0096] S301, continuously monitoring the second concentration c2 of the downstream NOx sensor;

[0097] S302, if c2≤C3, the injection amounts of the first ammonia nozzle and the second ammonia nozzle remain unchanged;

[0098] S303, if c2>C3, the first ammonia nozzle and the second ammonia nozzle are controlled to be closed.

[0099] In one possible implementation, in combination with Figure 1The above steps are specifically as follows: after the second ammonia nozzle B is opened to spray, the measured value of the rear-stage nitrogen oxide sensor 10 needs to be continuously monitored. If the second concentration c2 is not higher than the third concentration limit value C3, it indicates that the ammonia spraying has reached the effect of controlling NO x , and continuous monitoring can be performed. If the measured value of the second concentration c2 is higher than the third concentration limit value C3, it indicates that there is a fault, for example, the second ammonia nozzle B fails to reach the expected spraying amount, or the rear-stage selective catalytic reduction device 5 fails to fully react after ammonia is sprayed. At this time, the internal combustion engine 2 needs to be controlled to limit the speed and torque to prevent the emission from exceeding the standard, and an alarm needs to be prompted to indicate the related fault. If necessary, the internal combustion engine 2 and the aftertreatment system also need to be controlled to stop working.

[0100] In some embodiments, as shown in Figure 4 , the control method of the ammonia fuel internal combustion engine aftertreatment system also includes the following steps:

[0101] S401, obtaining the pressure difference value p through the pressure difference sensor;

[0102] S402, comparing the pressure difference value p with the preset first pressure difference limit value P1 and the second pressure difference limit value P2;

[0103] S403, if p

[0104] If p > P2, the heater is controlled to be turned on and operated at the first power.

[0105] If P1≤p≤P2, and the concentration of N2O is lower than the preset concentration, the heater is controlled to be turned off.

[0106] If P1≤p≤P2, and the concentration of N2O is higher than the preset concentration, the heater is controlled to be turned on and operated at the second power.

[0107] In one possible implementation, in combination with Figure 1 , the control method of the ammonia fuel internal combustion engine aftertreatment system also includes the following steps:

[0108] (1) When the internal combustion engine 2 is running, the pressure difference value p measured by the pressure difference sensor 12 needs to be read. If the pressure difference value p is lower than the first pressure difference limit value P1, it indicates that the particulate filter 61 may have been burned through or damaged due to other reasons. At this time, the internal combustion engine 2 needs to be controlled to limit the speed and torque to prevent the emission from exceeding the standard, and an alarm needs to be prompted to indicate the related fault. If necessary, the internal combustion engine 2 and the aftertreatment system also need to be controlled to stop working.

[0109] (2) If the pressure difference value p is higher than the second pressure difference limit value P2, it indicates that a large amount of carbon particles has accumulated in the particulate filter 61. At this time, the heater 62 needs to be turned on to provide the heat required for the regeneration reaction of the carbon particles. Therefore, at this time, the heater 62 needs to be turned on and operated at the first power.

[0110] (3) If the pressure difference value p is between the first pressure difference limit value P1 and the second pressure difference limit value P2, it indicates that the heater 62 does not need to be started based on the demand for carbon particle regeneration, but at this time attention should be paid to the emission control of N2O of the internal combustion engine 2. It should be noted that the ammonia internal combustion engine does not have a high original N2O emission level under all operating conditions, but is related to factors such as speed, torque, fuel injection pressure, injection advance angle, fuel ratio, etc. Only within a certain range, it has a high emission level. When the above parameters are all in the range that will produce high original N2O emission level, the electric heater 62 should be started and operated at the second power.

[0111] In some embodiments, as shown in Figure 5 the control method of the ammonia fuel internal combustion engine aftertreatment system further comprises:

[0112] S501, acquiring the third temperature t3 by the third temperature sensor;

[0113] S502, comparing the third temperature t3 with the preset second temperature limit value T2, the third temperature limit value T3 and the fourth temperature limit value T4;

[0114] S503, when p>P2, if T3≤t3≤T4, control the heater to be turned on and operated at the first power; if t3

[0115] When P1≤p≤P2, and the concentration of N2O is higher than the preset concentration, if T2≤t3≤T4, control the heater to be turned on and operated at the second power; if t3

[0116] In one possible implementation, in combination with Figure 1 the above steps are specifically: in the starting state, the heater 62 needs to be monitored by the third temperature sensor 13 to diagnose whether it is working normally, that is, whether it provides the required temperature, but not too high or too low. For the function of carbon particle regeneration, the third temperature t3 measured by the third temperature sensor needs to be between the third temperature limit value T3 and the fourth temperature limit value T4, which can be considered as normal work, and continue to monitor, and both too high and too low temperatures need to control the speed and torque of the internal combustion engine 2 and issue a heater 62 fault alarm. For the function of purifying N2O, the third temperature t3 measured by the third temperature sensor needs to be between the second temperature limit value T2 and the fourth temperature limit value T4, which can be considered as normal work, and continue to monitor, and both too high and too low temperatures need to control the speed and torque of the internal combustion engine 2 and issue a heater 62 fault alarm.

[0117] It should be noted that the above-mentioned limit values or reference values of temperature, concentration, power, etc. can be calculated or calibrated based on specific conditions during the development of the internal combustion engine and the aftertreatment system.

[0118] In order to make the scheme provided by the embodiments of the present application easier to understand, the control method of the ammonia fuel internal combustion engine aftertreatment system is described in detail below through one specific embodiment. As shown in the figure, the process includes the following steps: Figure 6

[0119] S601, obtaining the first temperature t1 and the second temperature t2 through the first temperature sensor and the second temperature sensor, and obtaining the first concentration c1 and the second concentration c2 through the front-stage nitrogen oxide sensor and the rear-stage nitrogen oxide sensor;

[0120] S602, comparing the first temperature t1 with the preset first temperature limit value T1, comparing the first concentration c1 with the preset first concentration limit value C1 and the second concentration limit value C2, and comparing the second concentration c2 with the preset second concentration limit value C2 and the third concentration limit value C3; wherein C1>C2>C3;

[0121] S603, judging whether t1 satisfies t1≤T1; if yes, executing S604; if no, executing S610;

[0122] S604, judging whether c1 satisfies c1≤C1; if yes, executing S605; if no, executing S610;

[0123] S605, judging whether c2 satisfies C2≤c2≤C1; if yes, executing S606; if no, executing S611;

[0124] S606, controlling the first ammonia gas nozzle to open and spray according to the preset injection amount, and controlling the second ammonia gas nozzle to open and spray according to the injection amount calculated based on the preset rule; the preset rule includes calculating the injection amount according to the conversion efficiency of the rear-stage selective catalytic reduction device;

[0125] S607, continuously monitoring the second concentration c2 of the rear-stage nitrogen oxide sensor;

[0126] S608, judging whether c2 satisfies c2≤C3; if yes, executing S609; if no, executing S610;

[0127] S609, controlling the injection amounts of the first ammonia gas nozzle and the second ammonia gas nozzle to be unchanged; and executing S607;

[0128] S610, controlling the first ammonia gas nozzle and the second ammonia gas nozzle to be closed;

[0129] S611, judging whether c2 satisfies c2

[0130] ​S612, control the first ammonia nozzle to open and spray according to the preset spraying amount, and control the second ammonia nozzle to close.

[0131] Meanwhile, the control method of the ammonia fuel internal combustion engine aftertreatment system also performs the following steps:

[0132] S701, obtain the pressure difference value p through the pressure difference sensor, and obtain the third temperature t3 through the third temperature sensor;

[0133] S702, compare the pressure difference value p with the preset first pressure difference limit value P1 and the second pressure difference limit value P2, and compare the third temperature t3 with the preset second temperature limit value T2, the third temperature limit value T3 and the fourth temperature limit value T4;

[0134] S703, determine whether p satisfies P1≤p≤P2; if yes, execute S704; if no, execute S707;

[0135] S704, determine whether the concentration of N2O is higher than the preset concentration; if yes, execute S705; if no, execute S708;

[0136] S705, control the heater to open and operate according to the second power;

[0137] S706, determine whether t3 satisfies T2≤t3≤T4; if yes, execute S705; if no, execute S708;

[0138] S707, determine whether p satisfies p>P2; if yes, execute S709; if no, execute S708;

[0139] S708, control the heater to close;

[0140] S709, control the heater to open and operate according to the first power;

[0141] S710, determine whether t3 satisfies T3≤t3≤T4; if yes, execute S709; if no, execute S708.

[0142] It should be noted that, Figure 6 The steps S601-S612 and the steps S701-S710 are two parallel control logics, and the order is not distinguished.

[0143] In summary, the ammonia fuel internal combustion engine aftertreatment system and the control method have the following beneficial effects: (1) under the premise of simplifying the system as much as possible and saving energy, the ammonia fuel internal combustion engine aftertreatment system can effectively remove almost all types of emission pollutants of the ammonia internal combustion engine, including NH3, NO x, N2O, HC, particulate matter, etc. (2) By reasonable hardware arrangement and control strategy, using as few temperature sensors, nitrogen oxide sensors as possible, the original exhaust, tail exhaust level monitoring of NH3, NOx, HC and other substances, and fault diagnosis of each processor in the aftertreatment system are realized. (3) The heating system is adopted to solve the problem of ammonia internal combustion engine particulate filter regeneration and the problem of temperature control of the nitrous oxide processor system.

[0144] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalents, the present application also intends to include these modifications and variations.

Claims

1. A control method of an ammonia fuelled internal combustion engine aftertreatment system, the ammonia fuelled internal combustion engine aftertreatment system comprising an ammonia tank, an internal combustion engine, a front selective catalytic reducer, an oxidation catalyst, a rear selective catalytic reducer and an integrated processor arranged in sequence; the ammonia tank comprising a first ammonia nozzle, the first ammonia nozzle being in communication with the internal combustion engine; a front nitrogen oxide sensor and a first temperature sensor being arranged on a pipeline between the oxidation catalyst and the rear selective catalytic reducer, a second temperature sensor being arranged on a pipeline between the rear selective catalytic reducer and the integrated processor, a rear nitrogen oxide sensor being arranged on a pipeline away from the internal combustion engine side of the integrated processor; the integrated processor comprising a particulate trap and a heater, the heater being sleeved outside the particulate trap, an exhaust gas flow passage being formed inside the particulate trap, a side wall of the exhaust gas flow passage being coated with an ammonia slip catalyst; characterized in that, The control method comprises: obtaining a first temperature t1 and a second temperature t2 through a first temperature sensor and a second temperature sensor, and obtaining a first concentration c1 and a second concentration c2 through a front-stage nitrogen oxide sensor and a rear-stage nitrogen oxide sensor; comparing the first temperature t1 with a preset first temperature limit T1, comparing the first concentration c1 with a preset first concentration limit C1 and a second concentration limit C2, and comparing the second concentration c2 with a preset second concentration limit C2 and a third concentration limit C3; wherein C1>C2>C3; if t1>T1, controlling the first ammonia nozzle to be closed; if t1≤T1 and c1>C1, controlling the first ammonia nozzle to be closed; if t1≤T1 and c1≤C1 and c2 The ammonia tank further comprises a second ammonia nozzle, which is in communication with a first connection position; wherein the first connection position is any position of a pipeline between the oxidation catalyst and the rear-stage selective catalytic reducer; 2. The control method according to claim 1, characterized by, The control method further comprises: if t1>T1, controlling the second ammonia nozzle to be closed; if t1≤T1 and c1>C1, controlling the second ammonia nozzle to be closed; if t1≤T1 and c1≤C1 and c2 if t1≤T1 and c1≤C1 and C2≤c2≤C1, controlling the second ammonia nozzle to be opened and sprayed at a spraying amount calculated based on a preset rule; the preset rule comprises calculating the spraying amount according to the conversion efficiency of the rear-stage selective catalytic reducer. The control of the second ammonia nozzle to be opened and sprayed at the spraying amount calculated based on the preset rule further comprises:

3. The control method according to claim 2, characterized by, continuously monitoring the second concentration c2 of the rear-stage nitrogen oxide sensor; if c2≤C3, controlling the spraying amounts of the first ammonia nozzle and the second ammonia nozzle to be unchanged; if c2>C3, controlling the first ammonia nozzle and the second ammonia nozzle to be closed. The ammonia fuel internal combustion engine aftertreatment system further comprises a dinitrogen monoxide processor, which is arranged on a pipeline away from the internal combustion engine on a side of the integrated processor; 4. The control method according to claim 1, characterized by, The ammonia fuel internal combustion engine aftertreatment system further comprises a differential pressure sensor, one end of which is in communication with a second connection position, and the other end of which is in communication with a third connection position; wherein the second connection position is any position of a pipeline between the rear-stage nitrogen oxide sensor and the integrated processor, and the third connection position is any position of a pipeline between the integrated processor and the dinitrogen monoxide processor; The control method further comprises: obtaining a differential pressure value p through the differential pressure sensor; comparing the differential pressure value p with a preset first differential pressure limit P1 and a second differential pressure limit P2; if p if p>P2, controlling the heater to be opened and operated at a first power; if P1≤p≤P2 and the concentration of N2O is lower than a preset concentration, controlling the heater to be closed; ​ If P1≤p≤P2 and the concentration of N2O is higher than the preset concentration, the heater is controlled to be turned on and run at the second power.

5. The control method according to claim 4, characterized by, A third temperature sensor is further arranged on the pipeline between the integrated processor and the nitrous oxide processor. When the heater is turned on, the control method further comprises: The third temperature t3 is obtained by the third temperature sensor; The third temperature t3 is compared with the preset second temperature limit T2, third temperature limit T3 and fourth temperature limit T4; When p>P2, if T3≤t3≤T4, the heater is controlled to be turned on and run at the first power; if t3 When P1≤p≤P2 and the concentration of N2O is higher than the preset concentration, if T2≤t3≤T4, the heater is controlled to be turned on and run at the second power; if t3 6. The control method according to claim 2, characterized by, The ammonia fuel internal combustion engine aftertreatment system further comprises a processor, which is in signal connection with the front-stage nitrous oxide sensor, the first temperature sensor, the second temperature sensor and the rear-stage nitrous oxide sensor, and is used for adjusting the injection amount of the second ammonia nozzle according to the temperatures detected by the first temperature sensor and the second temperature sensor and the nitrous oxide concentrations detected by the front-stage nitrous oxide sensor and the rear-stage nitrous oxide sensor.

7. The control method according to claim 5, characterized by, The ammonia fuel internal combustion engine aftertreatment system further comprises a processor, which is in signal connection with the pressure difference sensor and is used for controlling the start and stop of the heater according to the pressure difference detected by the pressure difference sensor.

8. The control method according to claim 7, characterized by A warning device is further arranged on the pipeline between the integrated processor and the nitrous oxide processor. The processor is in signal connection with the third temperature sensor and the warning device, and is used for monitoring the working state of the heater according to the temperature detected by the third temperature sensor in the starting state of the heater, so as to control the warning device to give an alarm.

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