阅读说明：本技术 发动机尾气后处理系统、方法、车辆及存储介质 (Engine exhaust aftertreatment system, method, vehicle and storage medium ) 是由 李子非 王鹏 孙爱洲 李丽 朱明健 张展腾 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种发动机尾气后处理系统、方法、车辆及存储介质。所述发动机尾气后处理系统包括EGR通路、排气主通路、排气支路、排气阀及氨气供给装置；EGR通路包括并联设置的第一循环通路和第二循环通路,氨气供给装置包括了第一固态氨存储设备和第二固态氨存储设备；其中,第一固态氨存储设备的体积较第二固态氨存储设备的小；第二循环通路上设置了上述第一固态氨存储设备和控制阀,排气支路上设置上述第二固态氨存储设备。所述发动机尾气后处理方法用于上述发动机尾气后处理系统中,使得无需另外设置电加热机构消耗额外能量,充分利用排气能量,保证在发动机全工况范围内氨气的充分提供,避免NO-(x)排放超标。(The invention discloses an engine tail gas aftertreatment system, an engine tail gas aftertreatment method, a vehicle and a storage medium. The engine tail gas aftertreatment system comprises an EGR passage, an exhaust main passage, an exhaust branch, an exhaust valve and an ammonia gas supply device; the EGR passage includes a first circulation passage and a second circulation passage arranged in parallel, and the ammonia gas supply device includes a first solid ammonia storageA device and a second solid ammonia storage device; wherein the first solid ammonia storage device has a smaller volume than the second solid ammonia storage device; the second circulation path is provided with the first solid ammonia storage device and a control valve, and the exhaust branch is provided with the second solid ammonia storage device. The engine tail gas post-treatment method is used in the engine tail gas post-treatment system, so that additional energy is consumed without additionally arranging an electric heating mechanism, the exhaust energy is fully utilized, the full supply of ammonia gas in the full working condition range of the engine is ensured, and NO is avoided x The emission exceeds the standard.)

1. An engine exhaust aftertreatment system, comprising:

an EGR passage (101), the EGR passage (101) communicating an exhaust system and an intake system of an engine (1); the EGR passage (101) comprises a first circulation passage and a second circulation passage which are arranged in parallel, and an EGR valve (8) and an EGR cooler (9) are arranged on the first circulation passage; a first solid ammonia storage device (21) and a control valve (10) are arranged on the second circulation path, and the control valve (10) is used for controlling the opening and closing of the second circulation path;

a main exhaust passage (102), the main exhaust passage (102) communicating with the exhaust system of the engine (1); the main exhaust passage (102) is provided with a first SCR (3) and a second SCR (6) in sequence from upstream to downstream;

an exhaust branch (103), the exhaust branch (103) being provided downstream of the second SCR (6); the air inlet and the air outlet of the exhaust branch (103) are communicated with the main exhaust passage (102); a second solid ammonia storage device (22) is arranged on the exhaust branch (103); the first solid ammonia storage device (21) has a smaller volume than the second solid ammonia storage device (22);

the exhaust valve (7) is arranged at the joint of the air inlet of the exhaust branch (103) and the exhaust main passage (102);

and the ammonia gas surge tank (23) is communicated with the first solid ammonia storage device (21) and the second solid ammonia storage device (22) and is used for conveying the ammonia gas released by the first solid ammonia storage device (21) and the second solid ammonia storage device (22) to the first SCR (3) and the second SCR (6).

2. The engine exhaust aftertreatment system according to claim 1, characterized in that the exhaust valve (7) is a three-way valve.

3. The engine exhaust aftertreatment system according to claim 1, further comprising a supercharger (2), a DOC (4) and a DPF (5), the supercharger (2), the first SCR (3), the DOC (4), the DPF (5) and the second SCR (6) being disposed in sequence on the exhaust main passage (102).

4. An engine exhaust gas after-treatment method for use in the engine exhaust gas after-treatment system according to any one of claims 1 to 3, characterized in that the engine exhaust gas after-treatment method comprises the steps of:

a1: detecting a temperature T of engine exhaust gases emitted by the second SCR (6)₁Judging whether T is satisfied₁＞T_set1，T_set1Is a first preset temperature; if not, closing the EGR valve (8), opening the control valve (10) to enable engine exhaust to pass through the second circulation passage, and further heating the first solid ammonia storage device (21); -simultaneously adjusting said exhaust valve (7) so that engine exhaust gases do not pass through said second solid ammonia storage device (22) on said exhaust branch (103); if yes, carrying out the next step;

a2: -adjusting said exhaust valve (7) to pass part of the engine exhaust gases through said exhaust branch (103) to preheat said second solid ammonia storage device (22);

a3: judging whether T is satisfied₁＞T_set2，T_set2Is a second preset temperature; if not, continuing the previous step; if yes, the EGR valve (8) is opened, the control valve (10) is closed, heating of the first solid ammonia storage device (21) is stopped, and meanwhile the exhaust valve (7) is adjusted to enable engine exhaust to only pass through the second solid ammonia storage device (22).

5. The engine exhaust aftertreatment method according to claim 4, further comprising the steps of:

a4: detecting the ammonia pressure P in the ammonia pressure stabilizing tank (23)_AmmoniaJudging whether P is satisfied_set1＜P_Ammonia＜P_set2，P_set1Is a first predetermined pressure value, P_set2Is a second predetermined pressure value, and P_set1＜P_set2；

A5: if P_AmmoniaDoes not satisfy P_set1＜P_Ammonia＜P_set2Adjusting the purge valve (7) to increase or decrease the amount of engine exhaust gas passing through the second solid ammonia storage device (22) until P_AmmoniaSatisfy P_set1＜P_Ammonia＜P_set2。

6. The engine exhaust aftertreatment method according to claim 4, further comprising the steps of:

b1: detecting the ammonia pressure P in the ammonia pressure stabilizing tank (23)_AmmoniaJudging whether P is satisfied_Ammonia＞P_set1，P_set1Is a first preset pressure value;

b2: if P_AmmoniaSatisfy P_Ammonia＞P_set1If the ammonia gas supply preparation is finished, satisfying the ammonia gas injection pressure condition, and continuing the next step; if P_AmmoniaDoes not satisfy P_Ammonia＞P_set1Then go back to step B1;

b3: detecting a temperature T in the first SCR (3)_SCR1And the temperature T in the second SCR (6)_SCR2And determining T_SCR1Whether or not T is satisfied_SCR1＞T_set3，T_SCR2Whether or not T is satisfied_SCR2＞T_set4，T_set3Is the critical operating temperature, T, of the first SCR (3)_set4Is the critical operating temperature of the second SCR (6);

b4: if T_SCR1Satisfy T_SCR1＞T_set3Then go to the next step, otherwise go back to step B3; if T_SCR2Satisfy T_SCR2＞T_set4Entering the next step; otherwise, go back to step B3.

7. The engine exhaust aftertreatment method of claim 6, further comprising, after step B4, the steps of:

b5: detecting NO at the inlet of the first SCR (3)_xConcentration N of₁And according to N₁Calculating a required ammonia injection amount for the first SCR (3); detecting NO at the inlet of the second SCR (6)_xConcentration N of₂And according to N₂Calculating a required ammonia injection amount for the second SCR (6);

b6: and B5, according to the ammonia gas demand injection amount calculated in the step B, injecting the ammonia gas in the ammonia gas surge tank (23) to the first SCR (3) and the second SCR (6).

8. The engine exhaust aftertreatment method of claim 7, further comprising, after step B6, the steps of:

b7: detecting NO at the outlet of the second SCR (6)_xConcentration N of₃And determining N₃Whether or not N is satisfied₃≤N_setWhen N is present_setIs a preset concentration value;

b8: if N is present₃Does not satisfy N₃≤N_setThen return to step B5 according to N₃And N_setThe deviation values of (a) trim the ammonia gas demand injection amounts of the first SCR (3) and the second SCR (6) in step B5 until N₃Satisfies N₃≤N_set。

9. A vehicle, characterized by comprising:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement the engine exhaust aftertreatment method of any one of claims 4-8.

10. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the engine exhaust aftertreatment method according to any one of claims 4-8.

Technical Field

The invention relates to the technical field of vehicle tail gas treatment, in particular to an engine tail gas after-treatment system, an engine tail gas after-treatment method, a vehicle and a storage medium.

Background

Nitrogen Oxides (NO)_x) Is one of the main pollutants of the diesel engine and aims to solve the problem of NO_xThe pollution problem is that two technical routes of EGR (Exhaust Gas Recirculation) and SCR (Selective Catalytic Reduction) are mainly adopted at present; the EGR technology works by reintroducing a certain amount of exhaust gas into the cylinder, reducing the oxygen concentration in the mixture in the cylinder, and reducing the maximum combustion temperature in the cylinder, thereby suppressing NO_xAnd (4) generating. The SCR technology is characterized in that a certain amount of urea aqueous solution is sprayed into tail gas, the urea aqueous solution is subjected to hydrolysis reaction to release ammonia gas, and the ammonia gas and NO in the tail gas_xA selective catalytic reduction reaction is carried out, thereby realizing the reduction of NO_xThe purpose of the discharge; of course, it is also possible to arrange a solid ammonia injection system to release ammonia gas by heating the solid ammonia.

For an engine tail gas aftertreatment system provided with a solid ammonia injection system, engine cooling water is usually adopted for heating and releasing ammonia gas, but when an engine is in cold start or runs under a long-time low-load working condition, the exhaust temperature of the engine is low, the temperature of cooling water of the engine is not high, the temperature condition that the solid ammonia injection system normally works cannot be met, the solid ammonia cannot be fully heated and enough ammonia gas is released, and NO is caused_xEmissions exceed target values(ii) a In the prior art, the solid ammonia heating release is promoted by additionally providing energy through electric heating, but the structural complexity and the economic cost of the engine are undoubtedly increased.

Accordingly, it is desirable to provide an engine exhaust aftertreatment system, method, vehicle and storage medium to address the above issues.

Disclosure of Invention

The invention aims to provide an engine tail gas aftertreatment system, an engine tail gas aftertreatment method, an engine tail gas aftertreatment vehicle and a storage medium, and aims to solve the problem that in the prior art, solid ammonia cannot be sufficiently heated to release ammonia gas and cause NO_xThe problem of emissions exceeding target values.

In order to realize the purpose, the following technical scheme is provided:

the invention provides an engine tail gas after-treatment system, which comprises:

an EGR passage that communicates an exhaust system and an intake system of an engine; the EGR passage comprises a first circulation passage and a second circulation passage which are arranged in parallel, and an EGR valve and an EGR cooler are arranged on the first circulation passage; a first solid ammonia storage device and a control valve are arranged on the second circulation passage, and the control valve is used for controlling the opening and closing of the second circulation passage;

a main exhaust passage in communication with the exhaust system of the engine; the exhaust main passage is sequentially provided with a first SCR and a second SCR from upstream to downstream;

an exhaust branch disposed downstream of the second SCR; the air inlet and the air outlet of the exhaust branch are communicated with the exhaust main passage; a second solid ammonia storage device is arranged on the exhaust branch; the first solid ammonia storage device is smaller in volume than the second solid ammonia storage device;

the exhaust valve is arranged at the joint of the air inlet of the exhaust branch and the exhaust main passage;

and the ammonia gas pressure stabilizing tank is communicated with the first solid ammonia storage device and the second solid ammonia storage device and is used for conveying ammonia gas released by the first solid ammonia storage device and the second solid ammonia storage device to the first SCR and the second SCR.

Further, the exhaust valve is a three-way valve.

Further, still include booster, DOC and DPF, the booster the first SCR the DOC the DPF with the second SCR sets gradually on the exhaust main route.

The invention also provides an engine exhaust gas after-treatment method for any one of the engine exhaust gas after-treatment systems, which comprises the following steps:

a1: detecting a temperature T of engine exhaust emitted by the second SCR₁Judging whether T is satisfied₁＞T_set1，T_set1Is a first preset temperature; if not, closing the EGR valve, opening the control valve, and enabling engine tail gas to pass through the second circulation passage to further heat the first solid ammonia storage device; simultaneously adjusting the exhaust valve to prevent engine exhaust from passing through the second solid ammonia storage device on the exhaust branch; if yes, carrying out the next step;

a2: adjusting the exhaust valve to enable part of engine exhaust to pass through the exhaust branch, and further preheating the second solid ammonia storage device;

a3: judging whether T is satisfied₁＞T_set2，T_set2Is a second preset temperature; if not, continuing the previous step; and if so, opening the EGR valve, closing the control valve to stop heating the first solid ammonia storage device, and adjusting the exhaust valve to enable the tail gas of the engine to only pass through the second solid ammonia storage device.

Further, the engine exhaust after-treatment method further comprises the following steps:

a4: detecting the ammonia pressure P in the ammonia pressure stabilizing tank_AmmoniaJudging whether P is satisfied_set1＜P_Ammonia＜P_set2，P_set1Is a first predetermined pressure value, P_set2Is a second predetermined pressure value, and P_set1＜P_set2；

A5: if P_AmmoniaDoes not satisfy P_set1＜P_Ammonia＜P_set2Adjusting the exhaust valve to increase or decrease the amount of engine exhaust gas passing through the second solid ammonia storage device until P_AmmoniaSatisfy P_set1＜P_Ammonia＜P_set2。

Further, the engine exhaust after-treatment method further comprises the following steps:

b1: detecting the ammonia pressure P in the ammonia pressure stabilizing tank_AmmoniaJudging whether P is satisfied_Ammonia＞P_set1，P_set1Is a first preset pressure value;

b2: if P_AmmoniaSatisfy P_Ammonia＞P_set1If the ammonia gas supply preparation is finished, satisfying the ammonia gas injection pressure condition, and continuing the next step; if P_AmmoniaDoes not satisfy P_Ammonia＞P_set1Then go back to step B1;

b3: detecting a temperature T in the first SCR_SCR1And temperature T in the second SCR_SCR2And determining T_SCR1Whether or not T is satisfied_SCR1＞T_set3，T_SCR2Whether or not T is satisfied_SCR2＞T_set4，T_set3Is the critical operating temperature, T, of the first SCR_set4Is a critical operating temperature of the second SCR;

b4: if T_SCR1Satisfy T_SCR1＞T_set3Then go to the next step, otherwise go back to step B3; if T_SCR2Satisfy T_SCR2＞T_set4Entering the next step; otherwise, go back to step B3.

Further, step B4 is followed by the following steps:

b5: detecting NO at the inlet of the first SCR_xConcentration N of₁And according to N₁Calculating the ammonia gas required injection amount of the first SCR; detecting NO at the inlet of the second SCR_xConcentration N of₂And according to N₂Calculating the ammonia gas required injection amount of the second SCR;

b6: and B5, according to the ammonia gas demand injection amount calculated in the step B, injecting the ammonia gas in the ammonia gas surge tank to the first SCR and the second SCR.

Further, step B6 is followed by the following steps:

b7: detecting NO at the outlet of the second SCR_xConcentration N of₃And determining N₃Whether or not N is satisfied₃≤N_setWhen N is present_setIs a preset concentration value;

b8: if N is present₃Does not satisfy N₃≤N_setThen return to step B5 according to N₃And N_setThe deviation values of (a) trim the ammonia gas demand injection amounts of the first SCR and the second SCR in step B5 until N₃Satisfies N₃≤N_set。

The present invention also provides a vehicle comprising:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement any of the engine exhaust after-treatment methods described above.

The present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements any of the engine exhaust aftertreatment methods described above.

Compared with the prior art, the invention has the beneficial effects that:

the engine tail gas aftertreatment system enables the engine tail gas to only heat the first solid ammonia storage device by controlling the control valve and the exhaust valve under the condition that the engine is in cold start or long-time low-load working condition operation and the exhaust temperature of the engine is low due to the arrangement of the second circulation passage, and can meet the working condition of the first solid ammonia storage device even if the temperature of the engine tail gas is low due to the fact that the volume of the first solid ammonia storage device is smaller than that of the second solid ammonia storage device, exhaust energy is fully utilized, and enough ammonia gas is released to the first solid ammonia storage device as far as possibleSCR, avoiding NO_xThe emission exceeds the standard.

The engine tail gas post-treatment method provided by the invention fully considers the condition that the temperature of the engine tail gas cannot meet the working condition of a large solid ammonia storage device and further cannot fully release ammonia gas when the engine is in cold start or operates under a long-time low-load working condition, and fully utilizes the energy of the engine tail gas by heating a first solid ammonia storage device with a small volume; the smaller first solid ammonia storage device can ensure that ammonia can be released quickly to achieve the working condition of ammonia injection even when the temperature of the tail gas of the engine is lower; when the temperature of the engine exhaust is high enough, the second solid ammonia storage device can be preheated by passing the engine exhaust through the second solid ammonia storage device; the use of the first solid ammonia storage device can be stopped until the temperature of the engine tail gas rises to a certain set value, and the energy of the engine tail gas can be completely absorbed by the second solid ammonia storage device with a larger volume to release ammonia gas; the engine tail gas post-treatment method fully considers the operation working condition of the engine, ensures that the ammonia gas is fully provided in the full working condition range, does not need to be additionally provided with an electric heating mechanism to consume extra energy, only utilizes the heat of the waste gas of the engine, reduces the economic cost, simplifies the structure of the engine, and also avoids NO (nitric oxide) caused by the fact that enough ammonia gas cannot be released during the cold start of the engine in the prior art_xIn case of emission exceeding the target value, NO_xThe emission meets the requirements of the regulations.

Drawings

FIG. 1 is a schematic diagram of an engine exhaust aftertreatment system according to an embodiment of the invention;

FIG. 2 is a flow chart illustrating control over heating the solid ammonia storage device in a method for aftertreatment of engine exhaust in accordance with an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the control of ammonia injection in the exhaust gas after-treatment method according to the embodiment of the present invention.

In the figure:

101. an EGR passage; 102. a main exhaust passage; 103. an exhaust branch;

1. an engine; 2. a supercharger; 3. a first SCR; 4. a DOC; 5. a DPF; 6. a second SCR; 7. an exhaust valve; 8. an EGR valve; 9. an EGR cooler; 10. a control valve;

11. a first temperature sensor; 12. a second temperature sensor; 13. a third temperature sensor; 14. a fourth temperature sensor; 21. a first solid-state ammonia storage device; 22. a second solid-state ammonia storage device; 23. ammonia gas pressure stabilizing tank; 24. a pressure sensor; 25. a first ammonia gas nozzle; 26. a second ammonia gas nozzle; 31. first NO_xA sensor; 32. second NO_xA sensor; 33. third NO_xA sensor.

Detailed Description

The following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

The embodiment provides an engine tail gas after-treatment system which is mainly used for treating NO in engine tail gas_xAnd (6) processing. Specifically, referring to fig. 1, the engine exhaust gas aftertreatment system includes an EGR passage 101, an exhaust main passage 102, an exhaust branch passage 103, and an ammonia gas supply device; the EGR passage 101 communicates the exhaust system and the intake system of the engine 1, and reduces NO in exhaust gas by exhaust gas circulation_xGenerating; the EGR passage 101 includes a first circulation passage provided with an EGR valve 8 and an EGR cooler 9 for realizing a conventional exhaust gas circulation process and a second circulation passage provided in parallel. The exhaust main passage 102 communicates with the exhaust system of the engine 1; the exhaust main passage 102 is provided with a first SCR3 and a second SCR6 in this order from upstream to downstream; two SCR are arranged on the main exhaust passage 102, so that exhaust can be exhausted after the exhaust gas of the engine is fully post-treated, and NO is reduced_xThe final discharge amount. Exhaust branch 103 is disposed downstream of second SCR 6; both the air inlet and the air outlet of the exhaust branch passage 103 communicate with the exhaust main passage 102. Go toThe ammonia gas supply apparatus includes a first solid ammonia storage device 21 and a second solid ammonia storage device 22, wherein the first solid ammonia storage device 21 has a smaller volume than the second solid ammonia storage device 22. In specific implementation, the first solid ammonia storage device 21 and the control valve 10 are arranged on the second circulation path, and the control valve 10 is used for controlling the opening and closing of the second circulation path. And the second solid ammonia storage device 22 described above is provided on the exhaust branch 103. The volume of the first solid ammonia storage device 21 is set to be smaller than that of the second solid ammonia storage device 22, so that the heating of the first solid ammonia storage device 21 is facilitated during cold start or long-time low-load working condition operation, and the purpose of quickly releasing ammonia gas is achieved. Optionally, the control valve 10 is provided upstream of the first solid ammonia storage device 21. Optionally, the EGR valve 8 is provided upstream of the EGR cooler 9.

Further, the engine exhaust gas aftertreatment system further comprises an exhaust valve 7, wherein the exhaust valve 7 is arranged at the connection position of an air inlet of the exhaust branch 103 and the exhaust main passage 102; the exhaust valve 7 is used to control whether the engine exhaust gas is directly discharged from the main exhaust passage 102 or discharged from the exhaust branch passage 103. Specifically, the exhaust valve 7 is a three-way valve having an inlet and two outlets, the inlet and one of the outlets of the exhaust valve 7 are both connected to the main exhaust passage 102, and the other outlet is connected to the exhaust branch 103, so that the engine exhaust on the main exhaust passage 102 can be selectively exhausted from the main exhaust passage 102 or the exhaust branch 103.

The engine exhaust gas after-treatment system of the embodiment enables the engine exhaust gas to only heat the first solid ammonia storage device 21 by controlling the control valve 10 and the exhaust valve 7 under the condition that the temperature of the exhaust gas of the engine 1 is low due to the cold start of the engine 1 or the long-time low-load working condition operation through the arrangement of the second circulation path, and the volume of the first solid ammonia storage device 21 is smaller than that of the second solid ammonia storage device 22, so that the working condition of the first solid ammonia storage device 21 can be met even if the temperature of the engine exhaust gas is low, the exhaust energy is fully utilized, enough ammonia gas is released to SCR as far as possible, and NO is avoided_xThe emission exceeds the standard.

In this embodiment, the ammonia gas supply apparatus further includes an ammonia gas surge tank 23, and the ammonia gas surge tank 23 is communicated with both the first solid-state ammonia storage device 21 and the second solid-state ammonia storage device 22, and is configured to convey ammonia gas released by the first solid-state ammonia storage device 21 and the second solid-state ammonia storage device 22 to the first SCR3 and the second SCR6, so as to implement SCR to complete tail gas treatment. Further, the ammonia gas supply apparatus further includes a first ammonia gas nozzle 25 and a second ammonia gas nozzle 26 connected to the ammonia gas surge tank 23; wherein the first ammonia nozzle 25 is configured to inject ammonia upstream of the first SCR3 and the second ammonia nozzle 26 is configured to inject ammonia upstream of the second SCR 6. The two ammonia nozzles are capable of independently injecting ammonia for use by the respective SCR.

Further, the engine exhaust gas aftertreatment system further includes a supercharger 2, a DOC (Oxidation catalytic converter) 4 and a DPF (Diesel Particulate Filter) 5, and the supercharger 2, the first SCR3, the DOC4, the DPF5 and the second SCR6 are sequentially disposed on the exhaust main passage 102, so as to achieve sufficient treatment of the engine exhaust gas. In this embodiment, an ASC (Ammonia Slip Catalyst) is integrated with the second SCR6, and the ASC mainly functions to eliminate excess or slipped NH₃I.e. excess NH₃Oxidation to N₂、N₂O、NO_X(ii) a At the same time, to catalyze NO again_X、NH₃Reaction is nitrogen N₂The exhaust treatment capability of the second SCR6 is improved.

The engine exhaust aftertreatment system also includes a plurality of temperature sensors. Still referring to fig. 1, in particular, the plurality of temperature sensors includes a first temperature sensor 11 disposed at an inlet of the first SCR3, a second temperature sensor 12 disposed at an outlet of the first SCR3, a third temperature sensor 13 disposed at an inlet of the second SCR6, and a fourth temperature sensor 14 disposed at an outlet of the second SCR 6. By collecting the signals of the first temperature sensor 11 and the second temperature sensor 12, the temperature T in the first SCR3 can be calculated_SCR1(ii) a By collecting the signals of the third temperature sensor 13 and the fourth temperature sensor 14, the temperature T in the second SCR6 may be calculated_SCR2。

Further, the air conditioner is provided with a fan,the engine exhaust aftertreatment system further comprises a plurality of NO_xA sensor. Specifically, referring to FIG. 1, a plurality of NOs_xThe sensor includes a first NO disposed at an inlet of the first SCR3_xSensor 31, second NO disposed at inlet of second SCR6_xSensor 32 and third NO disposed at outlet of second SCR6_xSensor 33 for detecting NO in engine exhaust entering first SCR3_xConcentration, NO in Engine exhaust entering second SCR6_xConcentration and NO in Engine exhaust after treatment with the first SCR3 and the second SCR6_xAnd (4) concentration.

The ammonia pressure stabilizing tank 23 is also provided with a pressure sensor 24 for detecting the ammonia pressure P in the ammonia pressure stabilizing tank 23_Ammonia。

Based on the engine exhaust after-treatment system, the embodiment also provides an engine exhaust after-treatment method for the engine exhaust after-treatment system; specifically, referring to fig. 2, the engine exhaust aftertreatment method includes the steps of:

a1: sensing temperature T of engine exhaust emitted by second SCR6₁Judging whether T is satisfied₁＞T_set1，T_set1Is a first preset temperature; if not, closing the EGR valve 8, opening the control valve 10, and enabling the engine tail gas to pass through the second circulation passage to further heat the first solid ammonia storage device 21; simultaneously adjusting the exhaust valve 7 to ensure that the engine exhaust does not pass through the second solid ammonia storage device 22 on the exhaust branch 103; if yes, carrying out the next step;

in step a1, considering that when the engine 1 is in cold start or is operated under a long-time low-load condition, the temperature of the exhaust gas flowing through the first SCR3 and the second SCR6 is not enough to heat the second solid ammonia storage device 22 with a large volume, and thus the ammonia gas cannot be fully released, which affects the supply of ammonia gas, in this step, the exhaust gas only passes through the first solid ammonia storage device 21 with a small volume, so that the exhaust gas normally works to complete the release of ammonia gas, and the released ammonia gas enters the ammonia gas pressure stabilizing tank 23; at the same time, all of the engine exhaust gas is discharged from the exhaust main passage 102.

A2: adjusting the exhaust valve 7 to allow part of the engine exhaust to pass through the exhaust branch 103, thereby preheating the second solid ammonia storage device 22;

in step A2, T₁＞T_set1I.e. the temperature of the exhaust gases from the engine rises to a certain extent, the exhaust valve 7 can be adjusted to allow part of the exhaust gases to flow through and heat the second solid ammonia storage device 22, which serves to fully utilize the energy of the exhaust gases to preheat the second solid ammonia storage device 22.

A3: judging whether T is satisfied₁＞T_set2，T_set2Is a second preset temperature; if not, continuing the previous step; if so, the EGR valve 8 is opened and the control valve 10 is closed to stop heating the first solid ammonia storage device 21, while the exhaust valve 7 is adjusted to let engine exhaust gases pass only the second solid ammonia storage device 22.

In step A3, when T is reached₁＞T_set2Now, it is indicated that the engine exhaust temperature is high enough to heat the second solid ammonia storage device 22, and the second circulation path may be closed, and the release of ammonia gas may be performed only by means of the second solid ammonia storage device 22.

The method for post-treating the engine tail gas provided by the embodiment fully considers the condition that the temperature of the engine tail gas cannot meet the working condition of a large solid ammonia storage device and further cannot fully release ammonia gas when the engine 1 is in cold start or runs under a long-time low-load working condition, and fully utilizes the energy of the engine tail gas by heating the first solid ammonia storage device 21 with a small volume; the smaller first solid ammonia storage device 21 ensures that ammonia gas can be released quickly to achieve the operating conditions for ammonia gas injection even when the engine exhaust gas temperature is low; when the engine exhaust temperature is sufficiently high, the second solid ammonia storage device 22 may be preheated by passing the engine exhaust portion through the second solid ammonia storage device 22; the use of the first solid-state ammonia storage device 21 can be stopped until the temperature of the engine exhaust gas rises to a certain set value, and the energy of the engine exhaust gas can be completely absorbed by the second solid-state ammonia storage device 22 with a larger volume to release ammonia gas; the engine tail gas aftertreatment method fully considers the operation of the engine 1The operating mode guarantees the sufficient supply of ammonia in its full operating mode within range, neither need to set up in addition that electric heating mechanism consumes extra energy, only utilizes 1 waste gas heat of engine, has reduced economic cost, has simplified 1 structure of engine, has still avoided among the prior art the unable NO that releases enough ammonia and lead to when engine 1 cold start_xIn case of emission exceeding the target value, NO_xThe emission meets the requirements of the regulations.

Further, the engine exhaust gas after-treatment method further comprises the following steps:

a4: detecting the ammonia pressure P in the ammonia surge tank 23_AmmoniaJudging whether P is satisfied_set1＜P_Ammonia＜P_set2，P_set1Is a first predetermined pressure value, P_set2Is a second predetermined pressure value, and P_set1＜P_set2；

A5: if P_AmmoniaDoes not satisfy P_set1＜P_Ammonia＜P_set2The purge valve 7 is adjusted to increase or decrease the amount of engine exhaust gas passing through the second solid ammonia storage device 22 until P_AmmoniaSatisfy P_set1＜P_Ammonia＜P_set2。

The steps A4 and A5 are set for ensuring the pressure of the ammonia gas in the ammonia gas pressure stabilizing tank 23 to be within a reasonable working pressure range and ensuring the normal injection of an ammonia gas nozzle; once the ammonia gas pressure is too large or too small, the release amount of ammonia gas is controlled by controlling the flow of the exhaust gas flowing through the second solid ammonia storage device 22, so that the ammonia gas pressure in the ammonia gas pressure stabilizing tank 23 is always maintained in a normal range, and the smooth work of the whole engine tail gas aftertreatment system is ensured.

The working steps are based on the control flow about heating the solid ammonia storage device under the condition that two solid ammonia storage devices are arranged; after the solid ammonia storage equipment finishes ammonia gas release, ammonia gas is required to be injected into SCR for tail gas treatment; therefore, referring to fig. 3, the engine exhaust gas after-treatment method of the embodiment further includes a control flow related to ammonia gas injection, and specifically includes the following steps:

b1: detecting the pressure P of the ammonia gas in the ammonia gas surge tank 23_AmmoniaJudging whether P is satisfied_Ammonia＞P_set1，P_set1Is a first preset pressure value;

b2: if P_AmmoniaSatisfy P_Ammonia＞P_set1If the ammonia gas supply preparation is finished, satisfying the ammonia gas injection pressure condition, and continuing the next step; if P_AmmoniaDoes not satisfy P_Ammonia＞P_set1Then go back to step B1;

the steps B1 and B2 are provided to ensure that the ammonia gas in the ammonia gas surge tank 23 is sufficiently stored to enable the ammonia gas nozzle to inject the ammonia gas normally.

B3: detecting a temperature T in a first SCR3_SCR1And temperature T in the second SCR6_SCR2And determining T_SCR1Whether or not T is satisfied_SCR1＞T_set3，T_SCR2Whether or not T is satisfied_SCR2＞T_set4，T_set3Is the critical operating temperature, T, of the first SCR3_set4A critical operating temperature of the second SCR 6;

b4: if T_SCR1Satisfy T_SCR1＞T_set3Then go to the next step, otherwise go back to step B3; if T_SCR2Satisfy T_SCR2＞T_set4Entering the next step; otherwise, go back to step B3.

The steps B3 and B4 are provided to ensure that temperature conditions are met during normal operation of the first SCR3 and the second SCR 6.

Further, after the ammonia gas is sufficiently prepared and the temperature adjustment is satisfied, the following steps are required:

b5: detecting NO at the inlet of the first SCR3_xConcentration N of₁And according to N₁Calculating a required ammonia injection amount for the first SCR 3; detecting NO at the inlet of the second SCR6_xConcentration N of₂And according to N₂Calculating a required ammonia injection amount for the second SCR 6;

b6: and B5, according to the ammonia gas demand injection amount calculated in the step B, injecting the ammonia gas in the ammonia gas surge tank 23 to the first SCR3 and the second SCR 6.

I.e. NO according to the desired treatment_xThe ammonia gas injection quantity required by each SCR is calculated according to the concentration, and the method is reasonableThe ammonia gas injection is arranged, so that the condition of ammonia gas waste or insufficient ammonia gas supply is avoided.

Step B6 is followed by the steps of:

b7: detecting NO at the outlet of the second SCR6_xConcentration N of₃And determining N₃Whether or not N is satisfied₃≤N_setWhen N is present_setIs a preset concentration value;

b8: if N is present₃Does not satisfy N₃≤N_setThen return to step B5 according to N₃And N_setThe deviation values of (A) correct the ammonia gas required injection amounts of the first SCR3 and the second SCR6 in the step B5 until N is₃Satisfies N₃≤N_set。

The steps B7 and B8 are provided for detecting NO in the finally exhausted exhaust gas_xWhether the concentration of (A) exceeds the standard or not; if the ammonia gas injection quantity exceeds the standard, the ammonia gas injection quantity in the two SCR devices needs to be adjusted according to the exceeding standard, and NO in the discharged tail gas is enabled to be as much as possible_xAnd (5) reaching the standard. In specific practice, N_setThe specific value can be obtained by looking up a table according to the rotating speed and the fuel injection quantity of the engine 1, N_setThe value of (b) should meet the corresponding emission legislation requirements.

Example two

The second embodiment of the present invention further provides a vehicle, and the components of the vehicle may include but are not limited to: the vehicle body, one or more processors, memory, and a bus connecting the various system components (including the memory and the processors).

The memory, which is a computer-readable storage medium, may be used to store software programs, computer-executable programs, and modules, such as program instructions corresponding to the engine exhaust aftertreatment method in embodiments of the present invention. The processor executes various functional applications and data processing of the vehicle by running software programs, instructions and modules stored in the memory, namely, the engine exhaust aftertreatment method is realized.

The memory can mainly comprise a program storage area and a data storage area, wherein the program storage area can store an operating system and an application program required by at least one function; the storage data area may store data created according to the use of the terminal, and the like. Further, the memory may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some examples, the memory may further include memory remotely located from the processor, and these remote memories may be connected to the vehicle over a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

EXAMPLE III

The third embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements an engine exhaust gas post-treatment method, and the engine exhaust gas post-treatment method includes the following steps:

a1: sensing temperature T of engine exhaust emitted by second SCR6₁Judging whether T is satisfied₁＞T_set1，T_set1Is a first preset temperature; if not, closing the EGR valve 8, opening the control valve 10, and enabling the engine tail gas to pass through the second circulation passage to further heat the first solid ammonia storage device 21; simultaneously adjusting the exhaust valve 7 to ensure that the engine exhaust does not pass through the second solid ammonia storage device 22 on the exhaust branch 103; if yes, carrying out the next step;

a2: adjusting the exhaust valve 7 to allow part of the engine exhaust to pass through the exhaust branch 103, thereby preheating the second solid ammonia storage device 22;

a3: judging whether T is satisfied₁＞T_set2，T_set2Is a second preset temperature; if not, continuing the previous step; if so, the EGR valve 8 is opened and the control valve 10 is closed to stop heating the first solid ammonia storage device 21, while the exhaust valve 7 is adjusted to let engine exhaust gases pass only the second solid ammonia storage device 22.

Of course, the embodiments of the present invention provide a computer-readable storage medium, whose computer-executable instructions are not limited to the operations of the method described above, but may also perform operations related to the engine exhaust aftertreatment method provided in any of the embodiments of the present invention.

From the above description of the embodiments, it is obvious for those skilled in the art that the present invention can be implemented by software and necessary general hardware, and certainly, can also be implemented by hardware, but the former is a better embodiment in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as a floppy disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a FLASH Memory (FLASH), a hard disk or an optical disk of a computer, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the methods according to the embodiments of the present invention.

In the above embodiment, each included unit and module is only divided according to functional logic, but is not limited to the above division as long as the corresponding function can be realized; in addition, specific names of the functional units are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present invention.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.