CN115045738B

CN115045738B - Control method and device of urea injection system, processor and urea injection system

Info

Publication number: CN115045738B
Application number: CN202210499798.3A
Authority: CN
Inventors: 张军; 谭治学; 张竞菲; 张瑜; 赵姗姗
Original assignee: Weichai Power Co Ltd; Weifang Weichai Power Technology Co Ltd
Current assignee: Weichai Power Co Ltd; Weifang Weichai Power Technology Co Ltd
Priority date: 2022-05-09
Filing date: 2022-05-09
Publication date: 2023-11-17
Anticipated expiration: 2042-05-09
Also published as: CN115045738A

Abstract

The application provides a control method and device of a urea injection system, a processor and the urea injection system. The method comprises the following steps: acquiring a first related parameter of a first selective catalytic conversion device; determining a first urea injection quantity of a first selective catalytic conversion device according to a first related parameter; obtaining a second phase Guan Canliang of a second selective catalytic conversion device; determining a second urea injection amount for a second selective catalytic conversion device based on the second phase Guan Canliang and the first related parameter; the first urea nozzle is controlled to inject urea based on the first urea injection amount, and the second urea nozzle is controlled to inject urea based on the second urea injection amount. The solution solves the problem that the urea injection quantity cannot be accurately determined in the prior art.

Description

Control method and device of urea injection system, processor and urea injection system

Technical Field

The application relates to the field of urea treatment, in particular to a control method and device of a urea injection system, a computer readable storage medium, a processor and the urea injection system.

Background

In order to meet emission requirements, an SCR (Selective Catalystic Reduction, selective catalytic reduction) device is installed in a current diesel engine treatment system, and nitrogen oxides are reduced to nuisance-free nitrogen by injecting urea aqueous solution into a catalyst installed in exhaust gas management, so that the emission is reduced, and the emission requirements are met. However, in the conventional scheme, the urea injection amount cannot be accurately determined during the control of the urea injection amount.

Disclosure of Invention

The application mainly aims to provide a control method and device of a urea injection system, a computer readable storage medium, a processor and the urea injection system, so as to solve the problem that the urea injection quantity cannot be accurately determined in the prior art.

According to an aspect of an embodiment of the present application, there is provided a control method of a urea injection system including a first urea nozzle, a first selective catalytic conversion device, a second urea nozzle, and a second selective catalytic conversion device distributed in this order from upstream to downstream, the method including: acquiring a first related parameter of the first selective catalytic conversion device, wherein the first related parameter is a parameter which can influence the urea injection quantity of the first selective catalytic conversion device; determining a first urea injection quantity of the first selective catalytic conversion device according to the first related parameter; obtaining a second phase Guan Canliang of the second selective catalytic conversion device; determining a second urea injection amount of the second selective catalytic conversion device according to the second phase Guan Canliang and the first related parameter, wherein the second related parameter is a parameter which can influence the urea injection amount of the second selective catalytic conversion device; and controlling the first urea nozzle to spray urea based on the first urea injection quantity, and controlling the second urea nozzle to spray urea based on the second urea injection quantity.

Optionally, the urea injection system further comprises a first nitrogen-oxygen sensor, a first stirrer, a first temperature sensor, an oxidation catalyst, a particulate matter trap and a second nitrogen-oxygen sensor, wherein the first nitrogen-oxygen sensor is located upstream of the first urea nozzle, the first stirrer is located between the first urea nozzle and the first temperature sensor, the first temperature sensor is located between the first stirrer and the first selective catalytic conversion device, the oxidation catalyst is located between the first selective catalytic conversion device and the particulate matter trap, the second nitrogen-oxygen sensor is located between the particulate matter trap and the second urea nozzle, and the first related parameter comprises at least one of: the device comprises a first temperature sensor, a first airspeed, a first gas flow and a second gas flow, wherein the first temperature is the temperature acquired by the first temperature sensor, the first airspeed is the airspeed between the first stirrer and the first selective catalytic conversion device, the first airspeed is the ratio of the volume of ammonia to the volume of a catalyst, the first gas flow is the gas flow acquired by the first nitrogen-oxygen sensor, and the second gas flow is the gas flow acquired by the second nitrogen-oxygen sensor.

Optionally, after acquiring the first relevant parameter of the first selective catalytic conversion device, the method further comprises: and constructing a first model according to the first temperature, the first airspeed and the first gas flow, and determining a first preset ammonia storage amount of the first selective catalytic conversion device and a first preset conversion efficiency of the first selective catalytic conversion device by adopting the first model, wherein the first preset conversion efficiency refers to a preset conversion rate of ammonia gas generated by urea into nitrogen oxides.

Optionally, determining the first urea injection amount of the first selective catalytic conversion device according to the first related parameter includes: determining a first feed-forward injection amount of the first selective catalytic conversion device based on the first temperature, the first gas flow rate, and the first predetermined conversion efficiency; performing ammonia storage correction according to the first preset ammonia storage amount, and determining a first ammonia correction injection amount; determining a first correction factor for the urea injection quantity according to the first predetermined conversion efficiency, the first temperature and the first airspeed; and determining the first urea injection quantity of the first selective catalytic conversion device according to the first feedforward injection quantity, the first ammonia correction injection quantity and the first correction factor.

Optionally, determining a first feed-forward injection amount of the first selective catalytic conversion device according to the first temperature, the first gas flow rate, and the first predetermined conversion efficiency includes: obtaining the product of the first gas flow and the first preset conversion efficiency to obtain a first basic urea injection quantity; obtaining the amount of oxidized ammonia obtained by oxidizing ammonia in the first selective catalytic conversion device; and carrying out ammonia storage correction on the ammonia oxidation amount by adopting the first temperature, and determining the first feedforward injection amount.

Optionally, performing ammonia storage correction according to the first predetermined ammonia storage amount, determining a first ammonia correction injection amount includes: acquiring a first actual ammonia storage amount according to the first temperature and the first airspeed; acquiring a first difference value between the first actual ammonia storage amount and the first preset ammonia storage amount; and adjusting the first actual ammonia storage amount by adopting the first difference value until the difference value between the first actual ammonia storage amount and the first preset ammonia storage amount is smaller than a first difference value threshold value, so as to obtain the first ammonia correction injection amount.

Optionally, determining a first correction factor for the urea injection quantity based on the first predetermined conversion efficiency, the first temperature, and the first airspeed includes: determining a first modified scaling factor from the first temperature and the first airspeed; obtaining a first actual conversion efficiency, wherein the first actual conversion efficiency refers to the actual conversion rate of ammonia gas generated by urea into oxynitride; acquiring a second difference between the first predetermined conversion efficiency and the first actual conversion efficiency; and obtaining the product of the first correction proportionality coefficient and the second difference value to obtain the first correction factor.

Optionally, determining the first urea injection amount of the first selective catalytic conversion device according to the first feed-forward injection amount, the first ammonia correction injection amount, and the first correction factor includes: obtaining the product of the first feedforward injection quantity and the first correction factor to obtain an initial first urea injection quantity; and obtaining the sum of the initial first urea injection quantity, the first feedforward injection quantity and the first ammonia correction quantity to obtain the first urea injection quantity.

Optionally, the urea injection system further comprises a second temperature sensor located between the first selective catalytic conversion device and the second urea nozzle, a second stirrer located between the second urea nozzle and the second selective catalytic conversion device, an ammonia slip trap located between the second selective catalytic conversion device and the third nitrogen oxide sensor located downstream of the ammonia slip trap, and a third nitrogen oxide sensor located downstream of the ammonia slip trap, the second related parameter comprising at least one of: the system comprises a first temperature sensor, a first space velocity and a second space velocity, wherein the first temperature is acquired by the first temperature sensor, the first space velocity is the space velocity between the first selective catalytic conversion device and the first stirrer, the first space velocity is the ratio of the volume of ammonia to the volume of a catalyst, and the second gas flow is acquired by the second nitrogen-oxygen sensor.

Optionally, after obtaining the second related parameter of the second selective catalytic conversion device, the method further includes: a second model is constructed based on the second temperature, the second space velocity, and the second phase Guan Canliang, and a second predetermined ammonia storage amount for the second selective catalytic conversion device and a second predetermined conversion efficiency for the second selective catalytic conversion device, which is a predetermined conversion rate of ammonia gas produced from urea to nitrogen oxides, are determined using the second model.

Optionally, determining a second urea injection amount of the second selective catalytic conversion device based on the second phase Guan Canliang and the first related parameter includes: determining a second feed-forward injection amount of the second selective catalytic conversion device based on the second temperature, the second airspeed, and the first related parameter; performing ammonia storage correction according to the second preset ammonia storage amount, and determining a second ammonia correction injection amount; and determining the second urea injection quantity of the second selective catalytic conversion device according to the second feedforward injection quantity and the second ammonia correction injection quantity.

Optionally, the first related parameter includes a second gas flow rate, and determining a second feed-forward injection amount of the second selective catalytic conversion device according to the second temperature, the second airspeed, and the first related parameter includes: determining feed-forward conversion efficiency according to the second temperature and the second airspeed, wherein the feed-forward conversion efficiency is the ratio of the ammonia storage amount to the second gas flow; and obtaining the product of the feedforward conversion efficiency and the second gas flow to obtain the second feedforward injection quantity.

Optionally, performing ammonia storage correction according to the second predetermined ammonia storage amount, determining a second ammonia correction injection amount includes: acquiring a second actual ammonia storage amount according to the second temperature and the second airspeed; acquiring a third difference value between the second actual ammonia storage amount and the second preset ammonia storage amount; and adjusting the second actual ammonia storage amount by adopting the third difference value until the difference value between the second actual ammonia storage amount and the second preset ammonia storage amount is smaller than a second difference value threshold value, so as to obtain the second ammonia correction injection amount.

Optionally, determining the second urea injection amount of the second selective catalytic conversion device according to the second feed-forward injection amount and the second ammonia correction injection amount includes: determining the deviation times of the third gas flow and the preset gas flow in a preset time period from the current time to the historical time; when the deviation times is smaller than a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device in a first mode to determine the second urea injection quantity; and when the deviation times is greater than or equal to a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device in a second mode to determine the second urea injection quantity.

Optionally, when the deviation number is smaller than the deviation number threshold, correcting the urea injection amount of the second selective catalytic conversion device in the first manner, to determine the second urea injection amount includes: acquiring actual gas flow; acquiring a fourth difference value between the actual gas flow and the third gas flow; determining a second modified scaling factor from the second temperature and the second airspeed; obtaining the product of the fourth difference value and the second correction proportionality coefficient to obtain a second correction factor; and obtaining the product of the second correction factor and a basic injection quantity to obtain the second urea injection quantity, wherein the basic injection quantity is obtained by determining according to the second temperature and the second airspeed.

Optionally, when the deviation number is greater than or equal to the deviation number threshold, correcting the urea injection amount of the second selective catalytic conversion device in a second manner, to determine the second urea injection amount includes: acquiring actual gas flow and average actual gas flow, wherein the average actual gas flow is an average value of the actual gas flow acquired at a plurality of moments in a preset time period from the current moment to the historical moment; obtaining an average third gas flow, wherein the average third gas flow is an average value of the third gas flows at a plurality of moments in the preset time period from the current moment to the historical moment, which are obtained by adopting the second model; obtaining a fifth difference between the average actual gas flow and the average third gas flow; filtering the fifth difference value by adopting an EWMA filtering mode to obtain a third correction factor; obtaining the sum of the second feedforward injection quantity and the second ammonia correction injection quantity to obtain an initial second urea injection quantity; and obtaining the product of the third correction factor and the initial second urea injection quantity to obtain the second urea injection quantity.

According to another aspect of the embodiment of the present invention, there is also provided a control device of a urea injection system, the urea injection system including a first urea nozzle, a first selective catalytic conversion device, a second urea nozzle, and a second selective catalytic conversion device distributed in this order from upstream to downstream, the device including a first acquisition unit, a first determination unit, a second acquisition unit, a second determination unit, and a control unit: the first acquisition unit is used for acquiring a first related parameter of the first selective catalytic conversion device, wherein the first related parameter is a parameter which can influence the urea injection quantity of the first selective catalytic conversion device; the first determining unit is used for determining a first urea injection quantity of the first selective catalytic conversion device according to the first related parameter; the second obtaining unit is configured to obtain a second phase Guan Canliang of the second selective catalytic conversion device, where the second related parameter is a parameter that affects an urea injection amount of the second selective catalytic conversion device; the second determining unit is configured to determine a second urea injection amount of the second selective catalytic conversion device according to the second phase Guan Canliang and the first related parameter; the control unit is used for controlling the first urea nozzle to spray urea based on the first urea injection quantity and controlling the second urea nozzle to spray urea based on the second urea injection quantity.

According to still another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium including a stored program, wherein the program performs any one of the methods.

According to still another aspect of the embodiment of the present invention, there is further provided a processor, where the processor is configured to execute a program, where the program executes any one of the methods.

According to another aspect of the embodiment of the present invention, there is further provided a urea injection system, including a first nitrogen-oxygen sensor, a first urea nozzle, a first stirrer, a first temperature sensor, a first selective catalytic conversion device, an oxidation catalytic converter, a particulate matter trap, a second nitrogen-oxygen sensor, a second temperature sensor, a second urea nozzle, a second stirrer, a second selective catalytic conversion device, an ammonia slip trap, a third nitrogen-oxygen sensor, and a controller, which are respectively in communication with the first nitrogen-oxygen sensor, the first urea nozzle, the first stirrer, the first temperature sensor, the first selective catalytic conversion device, the oxidation catalytic converter, the particulate matter trap, the second nitrogen-oxygen sensor, the second temperature sensor, the second urea nozzle, the second stirrer, the second selective catalytic conversion device, the ammonia slip trap, and the third nitrogen-oxygen sensor, and the controller.

In the embodiment of the invention, first relevant parameters of a first selective catalytic conversion device are obtained, then a first urea injection amount of the first selective catalytic conversion device is determined according to the first relevant parameters, then second relevant parameters of a second selective catalytic conversion device are obtained, then a second urea injection amount of the second selective catalytic conversion device is determined according to a second phase Guan Canliang and the first relevant parameters, finally urea is injected by a first urea nozzle based on the first urea injection amount, and urea is injected by a second urea nozzle based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

FIG. 1 illustrates a flow chart of a method of controlling a urea injection system according to an embodiment of the application;

FIG. 2 shows a schematic diagram of the urea injection system of the present application;

FIG. 3 illustrates a flow chart for determining a first urea injection quantity for a first selective catalytic conversion device;

FIG. 4 illustrates a flow chart for determining a second urea injection amount for a second selective catalytic conversion device;

fig. 5 shows a schematic structural diagram of a control device of a urea injection system according to an embodiment of the application.

Wherein the above figures include the following reference numerals:

10. a first urea nozzle; 11. a first selective catalytic conversion device; 12. a second urea nozzle; 13. a second selective catalytic conversion device; 14. a first nitrogen-oxygen sensor; 15. a first agitator; 16. a first temperature sensor; 17. an oxidation catalyst; 18. a particulate matter trap; 19. a second nitrogen-oxygen sensor; 20. a second temperature sensor; 21. a second stirrer; 22. ammonia escape trap; 23. a third nitrogen-oxygen sensor; 24. and a third temperature sensor.

Detailed Description

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe the embodiments of the application herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Furthermore, in the description and in the claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "connected" to the other element through a third element.

For convenience of description, the following will describe some terms or terminology involved in the embodiments of the present application:

first selective catalytic conversion device: a pre-SCR (selectively catalytic reduction, presec) for injecting urea before a first selective catalytic conversion device for reducing nitrogen oxides in exhaust emissions, the first selective catalytic conversion device being a first distance from a turbine of the system;

second selective catalytic conversion device: a post SCR (PosSCR) for injecting urea before a second selective catalytic conversion device for reducing nitrogen oxides in exhaust emission, wherein the second selective catalytic conversion device is at a second distance from a turbine position of the system, and the first distance is smaller than the second distance;

The particulate matter trap (Diesel Particulate Filter, abbreviated as DPF) is used for trapping the particulate matters in the tail gas, and when the trapped particulate matters reach a certain level, passive regeneration or active regeneration is required, so that the trapping capacity of the particulate matters trap on the particulate matters is recovered, and the particulate matters in the exhaust gas of the engine are filtered and trapped mainly through diffusion, deposition and impact mechanisms. The exhaust gas flows through the trap where particles are trapped in the filter element of the filter body, leaving cleaner exhaust gas to be discharged into the atmosphere. The prior wall-flow honeycomb ceramic filter is mainly used for engineering machinery and urban buses, and has the characteristics of simple operation and high filtering efficiency, but has the problems of regeneration of the filter and sensitivity to sulfur components in fuel oil;

an oxidation catalyst (Diesel Oxidation Catalysis, DOC for short) for converting NO (nitric oxide) in the exhaust gas to NO ₂ The method comprises the steps of (nitrogen dioxide) raising the temperature of the tail gas, assisting the normal operation of a particulate matter catcher and a selective catalytic conversion device, coating a noble metal catalyst (such as Pt and the like) on a honeycomb ceramic carrier, and enabling the substances to perform oxidation reaction with oxygen in the tail gas at a lower temperature and finally convert the substances into CO in order to reduce the chemical reaction activation energy of HC, CO and SOF in the tail gas of an engine ₂ And H ₂ O. The oxidation catalyst does not need a regeneration system and a control device, has the characteristics of simple structure and good reliability, and has been applied to modern small-sized engines to a certain extent;

an ammonia escape trap (Ammonia Slip Catalyst, ASC for short) for oxidizing excess ammonia;

the basic working principle of the particle catcher is as follows: when engine exhaust gas flows through an oxidation catalyst (DOC), CO and HC are first almost entirely oxidized to CO at temperatures of 200-600deg.C ₂ And H ₂ O, with NO being converted to NO ₂ . After the exhaust gas comes out of the DOC and enters a particulate matter trap (DPF), the particulates are trapped in a filter element of a filter body, cleaner exhaust gas is left to be discharged into the atmosphere, and the trapping efficiency of the DPF can reach more than 90 percent.

NO2 has strong oxidizing power to the trapped particles, and uses the generated NO ₂ Removal of particulates in particulate traps and formation of CO as an oxidizing agent ₂ And NO ₂ And is reduced to NO, thereby achieving the purpose of removing particlesA kind of electronic device.

DOC internal reaction principle:

2NO+O ₂ →2NO ₂

2CO+O ₂ →2CO ₂

2CH+O ₂ →CO ₂ +H ₂ O

principle of reaction in DPF:

C+2NO ₂ →CO ₂ +2NO

the regeneration of the filter comprises two methods of active regeneration and passive regeneration: active regeneration refers to the use of external energy to raise the temperature within the trap to ignite and burn the particles. When the temperature in the filter reaches 550 ℃, the deposited particulate matter will oxidize and burn, and if the temperature does not reach 550 ℃, excessive deposits will clog the filter, and an external energy source (such as an electric heater, a burner, or a change in engine operating conditions) is required to raise the temperature in the DPF to oxidize and burn the particulate matter. Passive regeneration refers to the use of a fuel additive or catalyst to reduce the ignition temperature of the particulates so that the particulates can burn on fire at normal engine exhaust temperatures. The additives (cerium, iron and strontium) are added to the fuel in a certain proportion, and too much of the additives have little effect, but if too little, it causes a delay in regeneration or an increase in regeneration temperature.

The basic principle of SCR is to inject fuel into the exhaust gas or to additionally add a reducing agent, with a suitable catalyst, to promote the reaction of the reducing agent with NOx while suppressing the non-selective oxidation reaction of the reducing agent with oxygen. Typical urea-SCR catalysts are V ₂ O ₅ /W ₂ O ₃ /TiO ₂ And metal oxide/zeolite. The vanadium-based catalyst has high selectivity to NOx and wide high-efficiency temperature window, and has high sulfur resistance, and has the defect of easy poisoning and high-temperature failure due to phosphorus components in lubricating oil; zeolite catalyst pair NH ₃ Has very strong adsorption capacity, but the adsorption capacity of the zeolite to HC is very strong at low temperature, the adsorption of HC can affect the low temperature performance of the catalyst, and the hydrothermal stability and sulfur resistance of the zeolite are poor, so that the practical use is limited and low sulfur is neededFuel content.

Sulfur oxides form sulfates in copper-based SCR, reducing catalyst activity, plugging pores, and reducing the conversion efficiency of SCR to NOx, thus, after certain sulfur oxides are trapped in SCR, it is necessary to desulfurize it. Sulfur poisoning has 2 mechanisms: generation (NH) ₄ )SO ₄ And the like, the active site of the SCR catalyst is reduced, small holes are blocked, and therefore NOx conversion efficiency is reduced; SO (SO) ₂ And SO ₃ With NO _x Competitive adsorption, reduction of NO _x Is adsorbed by the adsorption column;

reaction principle of SCR technology:

hydrolysis of urea to ammonia: (Urea injection System)

(NH2) ₂ CO+H ₂ O→2NH ₃ +CO ₂

SCR aftertreatment reaction: (SCR catalytic converter)

NO+NO ₂ +2NH ₃ →2N ₂ +3H ₂ O

4NO+O ₂ +4NH ₃ →4N ₂ +6H ₂ O

2NO ₂ +O ₂ +4NH ₃ →3N ₂ +6H ₂ O

The reductant actually involved in the selective catalytic reduction reaction in the SCR is ammonia (NH ₃ ) However, ammonia is highly corrosive, and therefore, liquid ammonia and aqueous ammonia are difficult to store and transport, and thus cannot be directly used in an on-vehicle SCR system. Now, an aqueous urea solution is generally used as a reducing agent. In addition, compared with urea aqueous solutions with other concentrations, the urea aqueous solution with the concentration of 32.5% has the lowest freezing point of-11 ℃, so that the urea aqueous solution with the concentration of 32.5% is generally used as a standard reducing agent of SCR internationally and named as AdBlue.

To prevent reductant wastage and NH after SCR catalyst ₃ Secondary pollution caused by leakage must be based on the actual NO of the engine _x Emissions and conversion efficiency of SCR catalysts, and the injection amount of the reducing agent is dynamically controlled, the injection strategy of the reducing agent is a hot spot and difficulty of SCR technology research. Since the aqueous urea solution is only NH ₃ Thus the urea aqueous solution is dividedSolution to NH ₃ Has a significant impact on the performance of the SCR.

As described in the background art, in order to solve the above-mentioned problems, in one embodiment of the present application, a control method, apparatus, computer readable storage medium, processor, and urea injection system for a urea injection system are provided.

According to an embodiment of the present application, there is provided a control method of a urea injection system including a first urea nozzle, a first selective catalytic conversion device, a second urea nozzle, and a second selective catalytic conversion device, which are sequentially distributed from upstream to downstream.

FIG. 1 is a flow chart of a method of controlling a urea injection system according to an embodiment of the application. As shown in fig. 1, the method comprises the steps of:

step S101, obtaining a first related parameter of the first selective catalytic conversion device, wherein the first related parameter is a parameter which can influence the urea injection quantity of the first selective catalytic conversion device;

step S102, determining a first urea injection quantity of the first selective catalytic conversion device according to the first related parameter;

step S103, obtaining a second phase Guan Canliang of the second selective catalytic conversion device;

step S104, determining a second urea injection quantity of the second selective catalytic conversion device according to the second related parameter and the first related parameter, wherein the second related parameter is a parameter which can influence the urea injection quantity of the second selective catalytic conversion device;

Step S105 of controlling the first urea nozzle to inject urea based on the first urea injection amount and controlling the second urea nozzle to inject urea based on the second urea injection amount.

In the above method, first relevant parameters of the first selective catalytic conversion device are obtained, then a first urea injection amount of the first selective catalytic conversion device is determined according to the first relevant parameters, then second relevant parameters of the second selective catalytic conversion device are obtained, then a second urea injection amount of the second selective catalytic conversion device is determined according to the second phase Guan Canliang and the first relevant parameters, finally urea is injected by the first urea nozzle based on the first urea injection amount, and urea is injected by the second urea nozzle based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.

In one embodiment of the present application, as shown in fig. 2, the urea injection system includes a first urea nozzle 10, a first selective catalytic conversion device 11, a second urea nozzle 12, and a second selective catalytic conversion device 13 sequentially distributed from upstream to downstream, the urea injection system further includes a first nitrogen-oxygen sensor 14, a first stirrer 15, a first temperature sensor 16, an oxidation catalyst 17, a particulate matter trap 18, and a second nitrogen-oxygen sensor 19, the first nitrogen-oxygen sensor 14 is located upstream of the first urea nozzle 10, the first stirrer 15 is located between the first urea nozzle 10 and the first temperature sensor 16, the first temperature sensor 16 is located between the first stirrer 15 and the first selective catalytic conversion device 11, the oxidation catalyst 17 is located between the first selective catalytic conversion device 11 and the particulate matter trap 18, the second nitrogen-oxygen sensor 19 is located between the particulate matter trap 18 and the second urea nozzle 12, and at least one of the parameters includes: a first temperature, a first space velocity, a first gas flow rate, and a second gas flow rate, wherein the first temperature is a temperature acquired by the first temperature sensor 16, the first space velocity is a space velocity between the first stirrer 15 and the first selective catalytic conversion device 11, the first space velocity is a ratio of a volume of ammonia gas to a volume of a catalyst, the first gas flow rate is a gas flow rate acquired by the first nitrogen-oxygen sensor 14, and the second gas flow rate is a gas flow rate acquired by the second nitrogen-oxygen sensor 19. In this embodiment, the first temperature, the first airspeed, the first gas flow, and the second gas flow may be obtained, and then the first urea injection amount of the first selective catalytic conversion device may be more accurately determined according to the first temperature, the first airspeed, the first gas flow, and the second gas flow.

In yet another embodiment of the present application, after obtaining the first related parameter of the first selective catalytic conversion device, the method further includes: a first model is constructed based on the first temperature, the first space velocity, and the first gas flow rate, and a first predetermined ammonia storage amount of the first selective catalytic conversion device and a first predetermined conversion efficiency of the first selective catalytic conversion device, which is a predetermined conversion rate of ammonia gas generated from urea into nitrogen oxides, are determined using the first model. In this embodiment, the first model is constructed, the first predetermined ammonia storage amount and the first predetermined conversion efficiency determined by the first model may be used as standard values, and the actually obtained data may be subsequently adjusted according to the standard values, so that the first urea injection amount is further ensured to be more accurate.

In another embodiment of the present application, determining a first urea injection amount of the first selective catalytic conversion device according to the first related parameter includes: determining a first feed-forward injection amount of the first selective catalytic conversion device based on the first temperature, the first gas flow rate, and the first predetermined conversion efficiency; performing ammonia storage correction according to the first preset ammonia storage amount, and determining a first ammonia correction injection amount; determining a first correction factor for the urea injection quantity based on the first predetermined conversion efficiency, the first temperature, and the first airspeed; and determining the first urea injection amount of the first selective catalytic conversion device based on the first feed-forward injection amount, the first ammonia correction injection amount, and the first correction factor. In this embodiment, the first urea injection amount has three influencing factors, that is, the first feedforward injection amount, the first ammonia correction injection amount and the first correction factor, and these three data are determined first, and then the first urea injection amount of the first selective catalytic conversion device may be determined more accurately according to the first feedforward injection amount, the first ammonia correction injection amount and the first correction factor.

In still another embodiment of the present application, determining a first feed-forward injection amount of the first selective catalytic conversion device based on the first temperature, the first gas flow rate, and the first predetermined conversion efficiency includes: obtaining the product of the first gas flow and the first preset conversion efficiency to obtain a first basic urea injection quantity; obtaining the amount of oxidized ammonia obtained by oxidizing ammonia in the first selective catalytic conversion device; and carrying out ammonia storage correction on the ammonia oxidation amount by adopting the first temperature to determine the first feedforward injection amount. In this embodiment, the first feed-forward injection amount of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first feed-forward injection amount.

In a specific embodiment of the present application, performing ammonia storage correction according to the first predetermined ammonia storage amount, determining a first ammonia correction injection amount includes: acquiring a first actual ammonia storage amount according to the first temperature and the first airspeed; acquiring a first difference between the first actual ammonia storage amount and the first predetermined ammonia storage amount; and adjusting the first actual ammonia storage amount by adopting the first difference value until the difference value between the first actual ammonia storage amount and the first preset ammonia storage amount is smaller than a first difference value threshold value, so as to obtain the first ammonia correction injection amount. In this embodiment, the first ammonia correction injection amount of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first ammonia correction injection amount.

In one embodiment, the first actual ammonia storage amount of the first selective catalytic conversion device may also be determined by the following formula:wherein θ represents a first actual ammonia storage amount, η represents a first predetermined conversion efficiency, k represents a frequency factor, nox represents a gas flow rate acquired by the first nitrogen-oxygen sensor, E represents an activation energy in J/mol, R represents a uniform gas constant, 8.3145 in J/mol/k, T represents a first temperature, and sv represents a first airspeed.

In yet another specific embodiment of the present application, determining a first correction factor for the urea injection quantity based on the first predetermined conversion efficiency, the first temperature, and the first airspeed includes: determining a first modified scaling factor based on the first temperature and the first airspeed; obtaining a first actual conversion efficiency, wherein the first actual conversion efficiency refers to the actual conversion rate of ammonia gas generated by urea into oxynitride; obtaining a second difference between the first predetermined conversion efficiency and the first actual conversion efficiency; and obtaining the product of the first correction proportion coefficient and the second difference value to obtain the first correction factor. In this embodiment, the first correction factor of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first correction factor.

In one embodiment, the first actual conversion efficiency may be collected by a second nitroxide sensor.

In another specific embodiment of the present application, determining the first urea injection amount of the first selective catalytic conversion device based on the first feed forward injection amount, the first ammonia correction injection amount, and the first correction factor includes: obtaining the product of the first feedforward injection quantity and the first correction factor to obtain an initial first urea injection quantity; and obtaining the sum of the initial first urea injection quantity, the first feedforward injection quantity and the first ammonia correction quantity to obtain the first urea injection quantity. In this embodiment, the first urea injection amount may be determined more accurately based on the obtained first feed-forward injection amount, first ammonia correction injection amount, and first correction factor.

Specifically, for the first predetermined conversion efficiency, if the second selective catalytic conversion device cannot meet the requirement, the first urea injection amount of the first selective catalytic conversion device can be adjusted by correcting the first correction factor, so as to improve the conversion efficiency of the second selective catalytic conversion device.

In a specific embodiment, the process for determining the first urea injection quantity is as shown in FIG. 3:

a first step of: constructing a first model according to the first temperature, the first airspeed and the first gas flow, and determining a first preset ammonia storage amount and a first preset conversion efficiency by adopting the first model;

and a second step of: calculating the product of the first gas flow and the first preset conversion efficiency to obtain a first basic urea injection quantity, carrying out ammonia storage correction on the ammonia oxidation gas quantity by adopting a first temperature, and then calculating the product of the ammonia oxidation gas quantity and the first basic urea injection quantity to obtain the first feedforward injection quantity;

and a third step of: acquiring an initial first actual ammonia storage amount according to the first temperature and the first airspeed, obtaining the reciprocal of the initial first actual ammonia storage amount, namely the first actual ammonia storage amount through an inverse model, carrying out efficiency correction on the first actual ammonia storage amount by adopting the first model, calculating a first difference value between the first actual ammonia storage amount and the first preset ammonia storage amount, and carrying out ammonia storage correction through the first difference value to obtain a first ammonia correction injection amount;

fourth step: acquiring a first actual conversion efficiency, acquiring a second difference value between the first actual conversion efficiency and a first preset conversion efficiency, acquiring a first correction proportionality coefficient, and calculating the product of the second difference value and the first correction proportionality coefficient to obtain a first correction factor;

Fifth step: calculating the product of the first feedforward injection quantity and the first correction factor to obtain an initial first urea injection quantity;

sixth step: and calculating the sum of the initial first urea injection quantity, the first feedforward injection quantity and the first ammonia correction quantity to obtain a first urea injection quantity.

In still another specific embodiment of the present application, as shown in fig. 2, the urea injection system further includes a second temperature sensor 20, a second stirrer 21, an ammonia slip trap 22, and a third nitrogen-oxygen sensor 23, wherein the second temperature sensor 20 is located between the first selective catalytic conversion device 11 and the second urea nozzle 12, the second stirrer 21 is located between the second urea nozzle 12 and the second selective catalytic conversion device 13, the ammonia slip trap 22 is located between the second selective catalytic conversion device 13 and the third nitrogen-oxygen sensor 23, the third nitrogen-oxygen sensor 23 is located downstream of the ammonia slip trap 22, and the second related parameters include at least one of: a second temperature, a second space velocity, and a third gas flow rate, wherein the second temperature is a temperature acquired by the second temperature sensor 20, the second space velocity is a space velocity between the first selective catalytic conversion device 11 and the second stirrer 21, the second space velocity is a ratio of a volume of ammonia gas to a volume of a catalyst, and the third gas flow rate is a gas flow rate acquired by the third nitrogen-oxygen sensor 23. In this embodiment, the second temperature, the second space velocity, and the third gas flow rate may be obtained, and then the second urea injection amount of the second selective catalytic conversion device may be more accurately determined according to the second temperature, the second space velocity, the second gas flow rate, and the third gas flow rate.

In one embodiment, the urea injection system further includes a third temperature sensor 24, the third temperature sensor 24 being located between the oxidation catalyst 17 and the particulate trap 18.

In one embodiment of the present application, after obtaining the second related parameter of the second selective catalytic conversion device, the method further includes: a second model is constructed based on the second temperature, the second space velocity, and the second phase Guan Canliang, and a second predetermined ammonia storage amount of the second selective catalytic conversion device and a second predetermined conversion efficiency of the second selective catalytic conversion device, which is a predetermined conversion rate of ammonia gas produced from urea into nitrogen oxides, are determined using the second model. In this embodiment, a second model is constructed, and the second predetermined ammonia storage amount and the second predetermined conversion efficiency determined by the second model may be used as standard values, and subsequently the actually obtained data may be adjusted according to the standard values, so that the second urea injection amount is further ensured to be more accurate.

In still another embodiment of the present application, determining a second urea injection amount of the second selective catalytic conversion device based on the second related parameter and the first related parameter includes: determining a second feed-forward injection amount of the second selective catalytic conversion device based on the second temperature, the second airspeed, and the first related parameter; performing ammonia storage correction according to the second preset ammonia storage amount, and determining a second ammonia correction injection amount; and determining the second urea injection amount of the second selective catalytic conversion device based on the second feedforward injection amount and the second ammonia correction injection amount. In this embodiment, the second urea injection amount has two influencing factors, that is, the second feedforward injection amount and the second ammonia correction injection amount, and the second urea injection amount of the second selective catalytic conversion device may be determined more accurately subsequently according to the second feedforward injection amount and the second ammonia correction injection amount.

In another embodiment of the present application, the first related parameter includes a second gas flow rate, and determining a second feed-forward injection amount of the second selective catalytic conversion device according to the second temperature, the second space velocity, and the first related parameter includes: determining a feed-forward conversion efficiency according to the second temperature and the second airspeed, wherein the feed-forward conversion efficiency is a ratio of the ammonia storage amount to the second gas flow; and obtaining the product of the feedforward conversion efficiency and the second gas flow rate to obtain the second feedforward injection quantity. In this embodiment, the second feedforward injection amount of the second selective catalytic conversion device may be further accurately determined, and then the second urea injection amount may be further accurately determined according to the accurate second feedforward injection amount.

In still another embodiment of the present application, performing ammonia storage correction according to the above second predetermined ammonia storage amount, determining a second ammonia correction injection amount includes: acquiring a second actual ammonia storage amount according to the second temperature and the second airspeed; acquiring a third difference between the second actual ammonia storage amount and the second predetermined ammonia storage amount; and adjusting the second actual ammonia storage amount by adopting the third difference value until the difference value between the second actual ammonia storage amount and the second preset ammonia storage amount is smaller than a second difference value threshold value, so as to obtain the second ammonia correction injection amount. In this embodiment, the second ammonia correction injection amount of the second selective catalytic conversion device may be further accurately determined, and then the second urea injection amount may be further accurately determined according to the accurate second ammonia correction injection amount.

In a specific embodiment of the present application, determining the second urea injection amount of the second selective catalytic conversion device based on the second feed-forward injection amount and the second ammonia correction injection amount includes: determining the deviation times of the third gas flow and the preset gas flow in a preset time period from the current time to the historical time; when the deviation times is smaller than a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device by adopting a first mode to determine the second urea injection quantity; and when the deviation times is greater than or equal to a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device by adopting a second mode to determine the second urea injection quantity. In this embodiment, if the transient deviation occurs, the urea injection amount of the second selective catalytic conversion device is corrected in the first manner, and if the deviation still exists after a period of time has elapsed, the urea injection amount of the second selective catalytic conversion device is corrected in the second manner, so that the second urea injection amount can be more accurately determined.

In one embodiment, the second actual conversion efficiency may be acquired by a third nitrogen-oxygen sensor.

In still another specific embodiment of the present application, when the number of deviations is smaller than a threshold number of deviations, the method for correcting the urea injection amount of the second selective catalytic conversion device in the first manner to determine the second urea injection amount includes: acquiring actual gas flow; acquiring a fourth difference value between the actual gas flow and the third gas flow; determining a second modified scaling factor based on the second temperature and the second airspeed; obtaining the product of the fourth difference value and the second correction proportion coefficient to obtain a second correction factor; and obtaining the product of the second correction factor and a basic injection quantity to obtain the second urea injection quantity, wherein the basic injection quantity is determined according to the second temperature and the second airspeed. In this embodiment, the deviation urea injection amount can be corrected more efficiently and accurately, so that the second urea injection amount can be determined more accurately.

In another specific embodiment of the present application, when the number of deviations is greater than or equal to a threshold number of deviations, correcting the urea injection amount of the second selective catalytic conversion device in a second manner to determine the second urea injection amount includes: acquiring an actual gas flow and an average actual gas flow, wherein the average actual gas flow is an average value of the actual gas flows acquired at a plurality of moments in a preset time period from a current moment to a historical moment; obtaining an average third gas flow, wherein the average third gas flow is an average value of the third gas flows at a plurality of times in the predetermined time period from the current time to the historical time, which is obtained by using the second model; obtaining a fifth difference between the average actual gas flow and the average third gas flow; filtering the fifth difference value by adopting an EWMA filtering mode to obtain a third correction factor; obtaining the sum of the second feedforward injection quantity and the second ammonia correction injection quantity to obtain an initial second urea injection quantity; and obtaining the product of the third correction factor and the initial second urea injection quantity to obtain the second urea injection quantity. In this embodiment, the deviation urea injection amount can be corrected more efficiently and accurately, so that the second urea injection amount can be determined more accurately.

In a specific embodiment, the process for determining the second urea injection quantity is as shown in FIG. 4:

a first step of: constructing a second model according to the second temperature, the second airspeed and the second gas flow, and determining a second predetermined ammonia storage amount and a second predetermined conversion efficiency by adopting the second model;

and a second step of: determining feedforward conversion efficiency according to the second temperature and the second airspeed, and calculating the product of the feedforward conversion efficiency and the second gas flow to obtain a second feedforward injection quantity;

and a third step of: acquiring a second actual ammonia storage amount according to the second temperature and the second airspeed, calculating a third difference value between the second actual ammonia storage amount and a second preset ammonia storage amount, and carrying out ammonia storage correction through the third difference value to obtain a second ammonia correction injection amount;

fourth step: under the condition that the urea injection quantity of the second selective catalytic conversion device is confirmed to be corrected by adopting a first mode, obtaining the actual gas flow, calculating a fourth difference value between the third gas flow and the actual gas flow, obtaining a second correction proportion coefficient, calculating the product of the fourth difference value and the second correction proportion coefficient to obtain a second correction factor, carrying out efficiency correction on the second actual conversion efficiency by adopting the first temperature and the second correction factor, and calculating the product of the second correction factor and the basic injection quantity to obtain a second urea injection quantity;

Fifth step: under the condition that the urea injection quantity of the second selective catalytic conversion device is corrected by the second mode, obtaining average actual gas flow and average third gas flow, calculating a fifth difference value between the average actual gas flow and the average third gas flow, filtering the fifth difference value by adopting an EWMA filtering mode to obtain a third correction factor, obtaining the sum of the second feedforward injection quantity and the second ammonia correction injection quantity, and performing product operation with the third correction factor to obtain the second urea injection quantity.

The embodiment of the application also provides a control device of the urea injection system, and the control device of the urea injection system can be used for executing the control method for the urea injection system. The following describes a control device of a urea injection system provided by an embodiment of the present application.

FIG. 5 is a schematic diagram of a control device for a urea injection system according to an embodiment of the application. As shown in fig. 5, the apparatus includes:

a first obtaining unit 100, configured to obtain a first related parameter of the first selective catalytic conversion device, where the first related parameter is a parameter that affects a urea injection amount of the first selective catalytic conversion device;

A first determining unit 200, configured to determine a first urea injection amount of the first selective catalytic conversion device according to the first related parameter;

a second obtaining unit 300 for obtaining a second phase Guan Canliang of the second selective catalytic conversion device, wherein the second related parameter is a parameter that affects the urea injection amount of the second selective catalytic conversion device;

a second determining unit 400 configured to determine a second urea injection amount of the second selective catalytic conversion device based on the second related parameter and the first related parameter;

and a control unit 500 for controlling the first urea nozzle to inject urea based on the first urea injection amount and controlling the second urea nozzle to inject urea based on the second urea injection amount.

In the above device, the first acquiring unit acquires a first related parameter of the first selective catalytic conversion device, the first determining unit determines a first urea injection amount of the first selective catalytic conversion device according to the first related parameter, the second acquiring unit acquires a second phase Guan Canliang of the second selective catalytic conversion device, the second determining unit determines a second urea injection amount of the second selective catalytic conversion device according to the second phase Guan Canliang and the first related parameter, the control unit controls the first urea nozzle to inject urea based on the first urea injection amount, and controls the second urea nozzle to inject urea based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

In yet another embodiment of the present application, the apparatus further includes a first construction unit, wherein the first construction unit is configured to construct a first model based on the first temperature, the first space velocity, and the first gas flow rate after obtaining the first related parameter of the first selective catalytic conversion apparatus, and determine a first predetermined ammonia storage amount of the first selective catalytic conversion apparatus and a first predetermined conversion efficiency of the first selective catalytic conversion apparatus using the first model, wherein the first predetermined conversion efficiency refers to a predetermined conversion rate of ammonia gas generated from urea into nitrogen oxide. In this embodiment, the first model is constructed, the first predetermined ammonia storage amount and the first predetermined conversion efficiency determined by the first model may be used as standard values, and the actually obtained data may be subsequently adjusted according to the standard values, so that the first urea injection amount is further ensured to be more accurate.

In another embodiment of the present application, the first determining unit includes a first determining module, a second determining module, a third determining module, and a fourth determining module, where the first determining module is configured to determine a first feed-forward injection amount of the first selective catalytic conversion device according to the first temperature, the first gas flow rate, and the first predetermined conversion efficiency; the second determining module is used for carrying out ammonia storage correction according to the first preset ammonia storage quantity and determining a first ammonia correction injection quantity; the third determining module is used for determining a first correction factor of the urea injection quantity according to the first preset conversion efficiency, the first temperature and the first airspeed; the fourth determining module is configured to determine the first urea injection amount of the first selective catalytic conversion device according to the first feed-forward injection amount, the first ammonia correction injection amount, and the first correction factor. In this embodiment, the first urea injection amount has three influencing factors, that is, the first feedforward injection amount, the first ammonia correction injection amount and the first correction factor, and these three data are determined first, and then the first urea injection amount of the first selective catalytic conversion device may be determined more accurately according to the first feedforward injection amount, the first ammonia correction injection amount and the first correction factor.

In yet another embodiment of the present application, the first determining module includes a first obtaining sub-module, a second obtaining sub-module, and a first determining sub-module, where the first obtaining sub-module is configured to obtain a product of the first gas flow rate and the first predetermined conversion efficiency, to obtain a first basic urea injection quantity; the second obtaining submodule is used for obtaining the ammonia oxidation amount obtained by oxidizing the ammonia in the first selective catalytic conversion device; the first determination submodule is used for carrying out ammonia storage correction on the ammonia oxidation amount by adopting the first temperature and determining the first feedforward injection amount. In this embodiment, the first feed-forward injection amount of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first feed-forward injection amount.

In a specific embodiment of the present application, the second determining module includes a third obtaining sub-module, a fourth obtaining sub-module, and a second determining sub-module, where the third obtaining sub-module is configured to obtain a first actual ammonia storage amount according to the first temperature and the first airspeed; the fourth obtaining submodule is used for obtaining a first difference value between the first actual ammonia storage amount and the first preset ammonia storage amount; the second determining submodule is used for adjusting the first actual ammonia storage amount by adopting the first difference value until the difference value between the first actual ammonia storage amount and the first preset ammonia storage amount is smaller than a first difference value threshold value, so as to obtain the first ammonia correction injection amount. In this embodiment, the first ammonia correction injection amount of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first ammonia correction injection amount.

In yet another specific embodiment of the present application, the third determining module includes a third determining sub-module, a fifth obtaining sub-module, a sixth obtaining sub-module, and a seventh obtaining sub-module, where the third determining sub-module is configured to determine a first correction scaling factor according to the first temperature and the first airspeed; the fifth obtaining submodule is used for obtaining the first actual conversion efficiency, wherein the first actual conversion efficiency refers to the actual conversion rate of ammonia gas generated by urea into oxynitride; the sixth obtaining submodule is used for obtaining a second difference value between the first preset conversion efficiency and the first actual conversion efficiency; the seventh obtaining submodule is used for obtaining the product of the first correction proportionality coefficient and the second difference value to obtain the first correction factor. In this embodiment, the first correction factor of urea of the first selective catalytic conversion device may be further accurately determined, and then the first urea injection amount may be further accurately determined according to the accurate first correction factor.

In another specific embodiment of the present application, the fourth determining module includes an eighth obtaining sub-module and a ninth obtaining sub-module, where the eighth obtaining sub-module is configured to obtain a product of the first feedforward injection quantity and the first correction factor to obtain an initial first urea injection quantity; and the ninth acquisition submodule is used for acquiring the sum of the initial first urea injection quantity, the first feedforward injection quantity and the first ammonia correction quantity to obtain the first urea injection quantity. In this embodiment, the first urea injection amount may be determined more accurately based on the obtained first feed-forward injection amount, first ammonia correction injection amount, and first correction factor.

In one embodiment of the present application, the apparatus further includes a second construction unit, wherein the second construction unit is configured to construct a second model based on the second temperature, the second space velocity, and the second phase Guan Canliang after obtaining the second related parameter of the second selective catalytic conversion apparatus, and determine a second predetermined ammonia storage amount of the second selective catalytic conversion apparatus and a second predetermined conversion efficiency of the second selective catalytic conversion apparatus using the second model, wherein the second predetermined conversion efficiency is a predetermined conversion rate of ammonia gas generated from urea into nitrogen oxide. In this embodiment, a second model is constructed, and the second predetermined ammonia storage amount and the second predetermined conversion efficiency determined by the second model may be used as standard values, and subsequently the actually obtained data may be adjusted according to the standard values, so that the second urea injection amount is further ensured to be more accurate.

In yet another embodiment of the present application, the second determining unit includes a fifth determining module for determining a second feed-forward injection amount of the second selective catalytic conversion device based on the second temperature, the second airspeed, and the first related parameter; the sixth determining module is used for performing ammonia storage correction according to the second preset ammonia storage amount and determining a second ammonia correction injection amount; the seventh determining module is configured to determine the second urea injection amount of the second selective catalytic conversion device according to the second feed-forward injection amount and the second ammonia correction injection amount. In this embodiment, the second urea injection amount has two influencing factors, that is, the second feedforward injection amount and the second ammonia correction injection amount, and the second urea injection amount of the second selective catalytic conversion device may be determined more accurately subsequently according to the second feedforward injection amount and the second ammonia correction injection amount.

In another embodiment of the present application, the first related parameter includes a second gas flow rate, the fifth determining module includes a fourth determining sub-module and a tenth obtaining sub-module, and the fourth determining sub-module is configured to determine a feed-forward conversion efficiency according to the second temperature and the second airspeed, where the feed-forward conversion efficiency is a ratio of the ammonia storage amount to the second gas flow rate; and the tenth acquisition submodule is used for acquiring the product of the feedforward conversion efficiency and the second gas flow to obtain the second feedforward injection quantity. In this embodiment, the second feedforward injection amount of the second selective catalytic conversion device may be further accurately determined, and then the second urea injection amount may be further accurately determined according to the accurate second feedforward injection amount.

In yet another embodiment of the present application, the sixth obtaining module includes an eleventh obtaining sub-module, a twelfth obtaining sub-module, and a fifth determining sub-module, where the eleventh obtaining sub-module is configured to obtain a second actual ammonia storage amount according to the second temperature and the second airspeed; the twelfth obtaining submodule is used for obtaining a third difference value between the second actual ammonia storage quantity and the second preset ammonia storage quantity; and the fifth determining submodule is used for adjusting the second actual ammonia storage amount by adopting the third difference value until the difference value between the second actual ammonia storage amount and the second preset ammonia storage amount is smaller than a second difference value threshold value, so as to obtain the second ammonia correction injection amount. In this embodiment, the second ammonia correction injection amount of the second selective catalytic conversion device may be further accurately determined, and then the second urea injection amount may be further accurately determined according to the accurate second ammonia correction injection amount.

In a specific embodiment of the present application, the seventh determining module includes a sixth determining sub-module, a seventh determining sub-module, and an eighth determining sub-module, where the sixth determining sub-module is configured to determine, in a predetermined period from a current time to a historical time, a number of deviations between the third gas flow and the predetermined gas flow; the seventh determining submodule is used for correcting the urea injection quantity of the second selective catalytic conversion device by adopting a first mode and determining the second urea injection quantity under the condition that the deviation times are smaller than a deviation times threshold value; the eighth determination submodule is configured to correct the urea injection quantity of the second selective catalytic conversion device in a second manner and determine the second urea injection quantity when the deviation number is greater than or equal to the deviation number threshold. In this embodiment, if the transient deviation occurs, the urea injection amount of the second selective catalytic conversion device is corrected in the first manner, and if the deviation still exists after a period of time has elapsed, the urea injection amount of the second selective catalytic conversion device is corrected in the second manner, so that the second urea injection amount can be more accurately determined.

In yet another specific embodiment of the present application, the seventh determining submodule is further configured to obtain an actual gas flow; acquiring a fourth difference value between the actual gas flow and the third gas flow; determining a second modified scaling factor based on the second temperature and the second airspeed; obtaining the product of the fourth difference value and the second correction proportion coefficient to obtain a second correction factor; and obtaining the product of the second correction factor and a basic injection quantity to obtain the second urea injection quantity, wherein the basic injection quantity is determined according to the second temperature and the second airspeed. In this embodiment, the deviation urea injection amount can be corrected more efficiently and accurately, so that the second urea injection amount can be determined more accurately.

In another specific embodiment of the present application, the eighth determining submodule is further configured to obtain an actual gas flow and an average actual gas flow, where the average actual gas flow is an average value of the actual gas flows obtained at a plurality of times in a predetermined period from a current time to a historical time; obtaining an average third gas flow, wherein the average third gas flow is an average value of the third gas flows at a plurality of times in the predetermined time period from the current time to the historical time, which is obtained by using the second model; obtaining a fifth difference between the average actual gas flow and the average third gas flow; filtering the fifth difference value by adopting an EWMA filtering mode to obtain a third correction factor; obtaining the sum of the second feedforward injection quantity and the second ammonia correction injection quantity to obtain an initial second urea injection quantity; and obtaining the product of the third correction factor and the initial second urea injection quantity to obtain the second urea injection quantity. In this embodiment, the deviation urea injection amount can be corrected more efficiently and accurately, so that the second urea injection amount can be determined more accurately.

The control device of the urea injection system comprises a processor and a memory, wherein the first acquisition unit, the first determination unit, the second acquisition unit, the second determination unit, the control unit and the like are all stored in the memory as program units, and the processor executes the program units stored in the memory to realize corresponding functions.

The processor includes a kernel, and the kernel fetches the corresponding program unit from the memory. The inner core can be provided with one or more than one, and the problem that the urea injection quantity cannot be accurately determined in the prior art is solved by adjusting the parameters of the inner core.

The memory may include volatile memory, random Access Memory (RAM), and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM), among other forms in computer readable media, the memory including at least one memory chip.

The embodiment of the invention provides a computer readable storage medium, wherein a program is stored, and the program is executed by a processor to realize the control method of the urea injection system.

The embodiment of the invention provides a processor which is used for running a program, wherein the control method of the urea injection system is executed when the program runs.

The embodiment of the application provides equipment, which comprises a processor, a memory and a program stored in the memory and capable of running on the processor, wherein the processor realizes at least the following steps when executing the program:

the embodiment of the application also provides a urea injection system, which comprises a first nitrogen-oxygen sensor, a first urea nozzle, a first stirrer, a first temperature sensor, a first selective catalytic conversion device, an oxidation catalytic converter, a particulate matter catcher, a second nitrogen-oxygen sensor, a second temperature sensor, a second urea nozzle, a second stirrer, a second selective catalytic conversion device, an ammonia escape catcher, a third nitrogen-oxygen sensor and a controller which are sequentially distributed from the upstream to the downstream, wherein the controller is respectively communicated with the first nitrogen-oxygen sensor, the first urea nozzle, the first stirrer, the first temperature sensor, the first selective catalytic conversion device, the oxidation catalytic converter, the particulate matter catcher, the second nitrogen-oxygen sensor, the second temperature sensor, the second urea nozzle, the second stirrer, the second selective catalytic conversion device, the ammonia escape catcher and the third nitrogen-oxygen sensor, and is used for executing any one of the methods.

In the above system, due to the inclusion of any one of the above methods, in the method, a first relevant parameter of the first selective catalytic conversion device is obtained first, then a first urea injection amount of the first selective catalytic conversion device is determined according to the first relevant parameter, then a second relevant parameter of the second selective catalytic conversion device is obtained, then a second urea injection amount of the second selective catalytic conversion device is determined according to the second phase Guan Canliang and the first relevant parameter, finally urea is injected from the first urea nozzle based on the first urea injection amount, and urea is injected from the second urea nozzle based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

The device herein may be a server, PC, PAD, cell phone, etc.

The application also provides a computer program product adapted to perform, when executed on a data processing device, a program initialized with at least the following method steps:

In the foregoing embodiments of the present application, the descriptions of the embodiments are emphasized, and for a portion of this disclosure that is not described in detail in this embodiment, reference is made to the related descriptions of other embodiments.

In the several embodiments provided in the present application, it should be understood that the disclosed technology may be implemented in other manners. The above-described embodiments of the apparatus are merely exemplary, and the division of the units may be a logic function division, and there may be another division manner when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interfaces, units or modules, or may be in electrical or other forms.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units described above, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the above-mentioned method of the various embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a removable hard disk, a magnetic disk, or an optical disk, or other various media capable of storing program codes.

From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

1) According to the control method of the urea injection system, first relevant parameters of a first selective catalytic conversion device are obtained, then a first urea injection amount of the first selective catalytic conversion device is determined according to the first relevant parameters, then second relevant parameters of a second selective catalytic conversion device are obtained, then a second urea injection amount of the second selective catalytic conversion device is determined according to the second phase Guan Canliang and the first relevant parameters, finally urea is injected by a first urea nozzle based on the first urea injection amount, and urea is injected by a second urea nozzle based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

2) According to the control device of the urea injection system, a first acquisition unit acquires a first related parameter of a first selective catalytic conversion device, a first determination unit determines a first urea injection amount of the first selective catalytic conversion device according to the first related parameter, a second acquisition unit acquires a second phase Guan Canliang of a second selective catalytic conversion device, a second determination unit determines a second urea injection amount of the second selective catalytic conversion device according to the second phase Guan Canliang and the first related parameter, and a control unit controls a first urea nozzle to inject urea based on the first urea injection amount and controls a second urea nozzle to inject urea based on the second urea injection amount. According to the scheme, the urea injection system is provided with the first selective catalytic conversion device, the second selective catalytic conversion device and the first urea nozzle and the second urea nozzle, and the two selective catalytic conversion devices are used for coordinated control, so that nitrogen oxides can be discharged more efficiently than the prior art, the scheme can accurately determine the first urea injection amount of the first selective catalytic conversion device and the second urea injection amount of the second selective catalytic conversion device, the requirement of high conversion rate of the selective catalytic conversion device can be met, the problem that the urea injection amount cannot be accurately determined in the prior art is solved, the urea injection amounts of the first urea nozzle and the second urea nozzle can be accurately controlled according to the first urea injection amount and the second urea injection amount, and the conversion rate of the nitrogen oxides is improved.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A control method of a urea injection system, characterized in that the urea injection system comprises a first urea nozzle, a first selective catalytic conversion device, a second urea nozzle and a second selective catalytic conversion device, which are distributed in order from upstream to downstream, the method comprising:

acquiring a first related parameter of the first selective catalytic conversion device, wherein the first related parameter is a parameter which can influence the urea injection quantity of the first selective catalytic conversion device;

determining a first urea injection quantity of the first selective catalytic conversion device according to the first related parameter;

obtaining a second phase Guan Canliang of the second selective catalytic conversion device;

determining a second urea injection amount of the second selective catalytic conversion device according to the second phase Guan Canliang and the first related parameter, wherein the second related parameter is a parameter which can influence the urea injection amount of the second selective catalytic conversion device;

Controlling the first urea nozzle to inject urea based on the first urea injection amount, and controlling the second urea nozzle to inject urea based on the second urea injection amount;

the urea injection system further comprises a first nitrogen-oxygen sensor, a first stirrer, a first temperature sensor, an oxidation catalyst, a particulate matter trap and a second nitrogen-oxygen sensor, wherein the first nitrogen-oxygen sensor is positioned upstream of the first urea nozzle, the first stirrer is positioned between the first urea nozzle and the first temperature sensor, the first temperature sensor is positioned between the first stirrer and the first selective catalytic conversion device, the oxidation catalyst is positioned between the first selective catalytic conversion device and the particulate matter trap, the second nitrogen-oxygen sensor is positioned between the particulate matter trap and the second urea nozzle, and the first related parameters comprise at least one of the following: the device comprises a first temperature, a first airspeed, a first gas flow and a second gas flow, wherein the first temperature is the temperature acquired by the first temperature sensor, the first airspeed is the airspeed between the first stirrer and the first selective catalytic conversion device, the first airspeed is the ratio of the volume of ammonia to the volume of a catalyst, the first gas flow is the gas flow acquired by the first nitrogen-oxygen sensor, and the second gas flow is the gas flow acquired by the second nitrogen-oxygen sensor;

After acquiring the first relevant parameter of the first selective catalytic conversion device, the method further includes:

constructing a first model according to the first temperature, the first airspeed and the first gas flow, and determining a first preset ammonia storage amount of the first selective catalytic conversion device and a first preset conversion efficiency of the first selective catalytic conversion device by adopting the first model, wherein the first preset conversion efficiency refers to a preset conversion rate of ammonia gas generated by urea into nitrogen oxides;

determining a first urea injection amount of the first selective catalytic conversion device according to the first related parameter, including:

determining a first feed-forward injection amount of the first selective catalytic conversion device based on the first temperature, the first gas flow rate, and the first predetermined conversion efficiency;

performing ammonia storage correction according to the first preset ammonia storage amount, and determining a first ammonia correction injection amount;

determining a first correction factor for the urea injection quantity according to the first predetermined conversion efficiency, the first temperature and the first airspeed;

and determining the first urea injection quantity of the first selective catalytic conversion device according to the first feedforward injection quantity, the first ammonia correction injection quantity and the first correction factor.

2. The method of claim 1, wherein determining a first feed-forward injection amount of the first selective catalytic conversion device based on the first temperature, the first gas flow rate, and the first predetermined conversion efficiency comprises:

obtaining the product of the first gas flow and the first preset conversion efficiency to obtain a first basic urea injection quantity;

obtaining the amount of oxidized ammonia obtained by oxidizing ammonia in the first selective catalytic conversion device;

and carrying out ammonia storage correction on the ammonia oxidation amount by adopting the first temperature, and determining the first feedforward injection amount.

3. The method according to claim 1, wherein performing ammonia storage correction based on the first predetermined ammonia storage amount, determining a first ammonia correction injection amount, comprises:

acquiring a first actual ammonia storage amount according to the first temperature and the first airspeed;

acquiring a first difference value between the first actual ammonia storage amount and the first preset ammonia storage amount;

and adjusting the first actual ammonia storage amount by adopting the first difference value until the difference value between the first actual ammonia storage amount and the first preset ammonia storage amount is smaller than a first difference value threshold value, so as to obtain the first ammonia correction injection amount.

4. The method of claim 1, wherein determining a first correction factor for the urea injection quantity based on the first predetermined conversion efficiency, the first temperature, and the first airspeed comprises:

determining a first modified scaling factor from the first temperature and the first airspeed;

obtaining a first actual conversion efficiency, wherein the first actual conversion efficiency refers to the actual conversion rate of ammonia gas generated by urea into oxynitride;

acquiring a second difference between the first predetermined conversion efficiency and the first actual conversion efficiency;

and obtaining the product of the first correction proportionality coefficient and the second difference value to obtain the first correction factor.

5. The method of claim 1, wherein determining the first urea injection amount of the first selective catalytic conversion device based on the first feed-forward injection amount, the first ammonia correction injection amount, and the first correction factor comprises:

obtaining the product of the first feedforward injection quantity and the first correction factor to obtain an initial first urea injection quantity;

and obtaining the sum of the initial first urea injection quantity, the first feedforward injection quantity and the first ammonia correction injection quantity to obtain the first urea injection quantity.

6. The method of claim 1, wherein the urea injection system further comprises a second temperature sensor located between the first selective catalytic conversion device and the second urea nozzle, a second agitator located between the second urea nozzle and the second selective catalytic conversion device, an ammonia slip trap located between the second selective catalytic conversion device and the third nitrogen sensor, and a third nitrogen oxygen sensor located downstream of the ammonia slip trap, the second related parameter comprising at least one of: the system comprises a first temperature sensor, a first space velocity and a second space velocity, wherein the first temperature is acquired by the first temperature sensor, the first space velocity is the space velocity between the first selective catalytic conversion device and the first stirrer, the first space velocity is the ratio of the volume of ammonia to the volume of a catalyst, and the second gas flow is acquired by the second nitrogen-oxygen sensor.

7. The method according to claim 6, further comprising, after acquiring the second related parameter of the second selective catalytic conversion device:

A second model is constructed based on the second temperature, the second space velocity, and the second phase Guan Canliang, and a second predetermined ammonia storage amount for the second selective catalytic conversion device and a second predetermined conversion efficiency for the second selective catalytic conversion device, which is a predetermined conversion rate of ammonia gas produced from urea to nitrogen oxides, are determined using the second model.

8. The method of claim 7, wherein determining a second urea injection amount for the second selective catalytic conversion device based on the second phase Guan Canliang and the first related parameter comprises:

determining a second feed-forward injection amount of the second selective catalytic conversion device based on the second temperature, the second airspeed, and the first related parameter;

performing ammonia storage correction according to the second preset ammonia storage amount, and determining a second ammonia correction injection amount;

and determining the second urea injection quantity of the second selective catalytic conversion device according to the second feedforward injection quantity and the second ammonia correction injection quantity.

9. The method of claim 8, wherein the first related parameter comprises a second gas flow rate, and determining a second feed-forward injection amount for the second selective catalytic conversion device based on the second temperature, the second space velocity, and the first related parameter comprises:

Determining feed-forward conversion efficiency according to the second temperature and the second airspeed, wherein the feed-forward conversion efficiency is the ratio of the ammonia storage amount to the second gas flow;

and obtaining the product of the feedforward conversion efficiency and the second gas flow to obtain the second feedforward injection quantity.

10. The method of claim 8, wherein performing ammonia storage correction based on the second predetermined ammonia storage amount, determining a second ammonia correction injection amount, comprises:

acquiring a second actual ammonia storage amount according to the second temperature and the second airspeed;

acquiring a third difference value between the second actual ammonia storage amount and the second preset ammonia storage amount;

and adjusting the second actual ammonia storage amount by adopting the third difference value until the difference value between the second actual ammonia storage amount and the second preset ammonia storage amount is smaller than a second difference value threshold value, so as to obtain the second ammonia correction injection amount.

11. The method of claim 8, wherein determining the second urea injection amount of the second selective catalytic conversion device based on the second feed-forward injection amount and the second ammonia correction injection amount comprises:

Determining the deviation times of the third gas flow and the preset gas flow in a preset time period from the current time to the historical time;

when the deviation times is smaller than a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device in a first mode to determine the second urea injection quantity;

and when the deviation times is greater than or equal to a deviation times threshold value, correcting the urea injection quantity of the second selective catalytic conversion device in a second mode to determine the second urea injection quantity.

12. The method according to claim 11, wherein, in the case where the number of deviations is smaller than a threshold number of deviations, correcting the urea injection quantity of the second selective catalytic conversion device in the first manner, determining the second urea injection quantity includes:

acquiring actual gas flow;

acquiring a fourth difference value between the actual gas flow and the third gas flow;

determining a second modified scaling factor from the second temperature and the second airspeed;

obtaining the product of the fourth difference value and the second correction proportionality coefficient to obtain a second correction factor;

And obtaining the product of the second correction factor and a basic injection quantity to obtain the second urea injection quantity, wherein the basic injection quantity is obtained by determining according to the second temperature and the second airspeed.

13. The method according to claim 11, wherein, in the case where the number of deviations is greater than or equal to a threshold number of deviations, correcting the urea injection quantity of the second selective catalytic conversion device in a second manner, determining the second urea injection quantity includes:

acquiring actual gas flow and average actual gas flow, wherein the average actual gas flow is an average value of the actual gas flow acquired at a plurality of moments in a preset time period from the current moment to the historical moment;

obtaining an average third gas flow, wherein the average third gas flow is an average value of the third gas flows at a plurality of moments in the preset time period from the current moment to the historical moment, which are obtained by adopting the second model;

obtaining a fifth difference between the average actual gas flow and the average third gas flow;

filtering the fifth difference value by adopting an EWMA filtering mode to obtain a third correction factor;

Obtaining the sum of the second feedforward injection quantity and the second ammonia correction injection quantity to obtain an initial second urea injection quantity;

and obtaining the product of the third correction factor and the initial second urea injection quantity to obtain the second urea injection quantity.

14. A control device of a urea injection system, characterized in that the urea injection system comprises a first urea nozzle, a first selective catalytic conversion device, a second urea nozzle and a second selective catalytic conversion device, which are distributed in sequence from upstream to downstream, the device comprising:

a first obtaining unit, configured to obtain a first related parameter of the first selective catalytic conversion device, where the first related parameter is a parameter that affects a urea injection amount of the first selective catalytic conversion device;

the first determining unit is used for determining a first urea injection quantity of the first selective catalytic conversion device according to the first related parameter;

a second obtaining unit, configured to obtain a second phase Guan Canliang of the second selective catalytic conversion device, where the second related parameter is a parameter that affects an urea injection amount of the second selective catalytic conversion device;

A second determining unit configured to determine a second urea injection amount of the second selective catalytic conversion device based on the second phase Guan Canliang and the first related parameter;

a control unit for controlling the first urea nozzle to inject urea based on the first urea injection amount and controlling the second urea nozzle to inject urea based on the second urea injection amount;

A first construction unit, configured to construct a first model according to the first temperature, the first space velocity and the first gas flow rate after acquiring a first related parameter of the first selective catalytic conversion device, and determine a first predetermined ammonia storage amount of the first selective catalytic conversion device and a first predetermined conversion efficiency of the first selective catalytic conversion device by using the first model, where the first predetermined conversion efficiency refers to a predetermined conversion rate of ammonia gas generated by urea into nitrogen oxide;

the first determining unit comprises a first determining module, a second determining module, a third determining module and a fourth determining module, wherein the first determining module is used for determining a first feed-forward injection quantity of the first selective catalytic conversion device according to the first temperature, the first gas flow and the first preset conversion efficiency; the second determining module is used for carrying out ammonia storage correction according to the first preset ammonia storage quantity and determining a first ammonia correction injection quantity; the third determining module is used for determining a first correction factor of the urea injection quantity according to the first preset conversion efficiency, the first temperature and the first airspeed; the fourth determining module is configured to determine the first urea injection amount of the first selective catalytic conversion device according to the first feed-forward injection amount, the first ammonia correction injection amount, and the first correction factor.

15. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored program, wherein the program performs the method of any one of claims 1 to 13.

16. A processor for running a program, wherein the program when run performs the method of any one of claims 1 to 13.

17. A urea injection system, comprising: a first nitrogen-oxygen sensor, a first urea nozzle, a first agitator, a first temperature sensor, a first selective catalytic conversion device, an oxidation catalytic converter, a particulate trap, a second nitrogen-oxygen sensor, a second temperature sensor, a second urea nozzle, a second agitator, a second selective catalytic conversion device, an ammonia slip trap, a third nitrogen-oxygen sensor, and a controller in communication with the first nitrogen-oxygen sensor, the first urea nozzle, the first agitator, the first temperature sensor, the first selective catalytic conversion device, the oxidation catalytic converter, the particulate trap, the second nitrogen-oxygen sensor, the second temperature sensor, the second urea nozzle, the second agitator, the second selective catalytic conversion device, the ammonia slip trap, and the third nitrogen-oxygen sensor, respectively, in order from upstream to downstream, the controller being configured to perform the method of any one of claims 1-13.