CN115045736B

CN115045736B - Engine nitrogen oxide emission control method, control device and storage medium

Info

Publication number: CN115045736B
Application number: CN202111365000.8A
Authority: CN
Inventors: 刘世龙
Original assignee: Great Wall Motor Co Ltd
Current assignee: Great Wall Motor Co Ltd
Priority date: 2021-11-17
Filing date: 2021-11-17
Publication date: 2023-10-24
Anticipated expiration: 2041-11-17
Also published as: CN115045736A

Abstract

The invention provides a control method, a control device and a storage medium for emission of nitrogen oxides of an engine, wherein the method comprises the steps of judging whether an adjusting mechanism of the exhaust aftertreatment system of the engine needs to be adjusted according to working condition parameters of the current working condition of the exhaust aftertreatment system of the engine and a preset adjusting table, wherein the adjusting table comprises working condition points needing to be adjusted; if the adjusting mechanism of the exhaust aftertreatment system of the engine needs to be adjusted, determining an adjusting quantity according to an adjusting table, wherein the adjusting table also comprises adjusting quantities corresponding to each of a plurality of working condition points, the working condition points of which need to be adjusted; and adjusting the adjusting mechanism according to the adjusting quantity so that the value of an influence factor affecting the conversion efficiency of the nitrogen oxides by the exhaust gas aftertreatment system of the engine is within a preset range. The invention can improve the conversion efficiency of the engine exhaust aftertreatment system to nitrogen oxides.

Description

Engine nitrogen oxide emission control method, control device and storage medium

Technical Field

The invention relates to the technical field of tail gas treatment, in particular to an engine nitrogen oxide emission control method, an engine nitrogen oxide emission control device and a storage medium.

Background

Nitrogen oxides are the main pollutant of automobile exhaust, and the prior art reduces NO by selective catalytic reduction (Selective Catalytic Reduction, SCR) technology _x And (5) discharging.

The basic working principle of SCR is: when the engine is running, urea aqueous solution is injected into the exhaust pipe of the engine, and hydrolysis reaction of the urea aqueous solution in high-temperature exhaust gas is carried out to generate NH ₃ (or released as solid ammonia), NH ₃ Under the action of catalyst, with NO and NO ₂ Chemical reaction is carried out to remove NO _x Is a target of (a).

The interior of the SCR involves complex chemical reactions, and the content of various substances, such as oxygen, water vapor, etc., may affect the conversion efficiency of the SCR to nitrogen oxides, so that the conversion efficiency of the SCR to nitrogen oxides is low.

How to improve the conversion efficiency of SCR to nitrogen oxides is a technical problem which needs to be solved urgently in the prior art.

Disclosure of Invention

In view of the above, the invention provides a method, a device, a terminal and a storage medium for controlling the emission of nitrogen oxides of an engine, which can solve the problem of low conversion efficiency of nitrogen oxides by SCR.

In a first aspect, an embodiment of the present invention provides a method for controlling emission of nitrogen oxides from an engine, including:

judging whether an adjusting mechanism of the engine exhaust aftertreatment system needs to be adjusted according to working condition parameters of the current working condition of the engine exhaust aftertreatment system and a preset adjusting table, wherein the adjusting table comprises a plurality of working condition points, each working condition point corresponds to one group of working condition parameters, each two groups of working condition parameters are not identical, and the adjusting table comprises working condition points needing to be adjusted for the adjusting mechanism;

If the adjusting mechanism of the engine exhaust aftertreatment system needs to be adjusted, determining an adjusting quantity according to the adjusting table, wherein the adjusting table also comprises adjusting quantities corresponding to the working condition points, which need to be adjusted, of the plurality of working condition points;

and adjusting the adjusting mechanism according to the adjusting quantity so as to enable the value of an influence factor affecting the exhaust aftertreatment system of the engine on the conversion efficiency of the nitrogen oxides to be in a preset range.

In one possible implementation, the operating condition parameter is NO at an inlet of an SCR catalyst in the engine exhaust aftertreatment system _x A nozzle is arranged at an inlet of the SCR catalyst, the nozzle is used for injecting oxygen or preset gas, the preset gas is gas which does not participate in chemical reaction in the SCR catalyst, the regulating mechanism is the nozzle, the influencing factor is the concentration of oxygen in the SCR catalyst, and the method comprises the following steps:

according to the NO at the inlet of the SCR catalyst under the current working condition _x Judging whether the nozzle needs to be regulated or not according to the content of the SCR catalyst, the temperature of the SCR catalyst and the regulation table;

If the nozzle needs to be regulated, determining a regulating quantity according to the regulating table;

and according to the regulating quantity, regulating the nozzle, and controlling the nozzle to spray oxygen or preset gas with the absolute value of the regulating quantity, so that the concentration of the oxygen in the SCR catalyst is in a preset range corresponding to the oxygen concentration.

In one possible implementation manner, the adjusting the nozzle according to the adjustment amount, and controlling the nozzle to spray oxygen or preset gas with an absolute value of the adjustment amount, so that the concentration of oxygen in the SCR catalyst is within a corresponding preset range includes:

if the regulating quantity is positive, controlling the nozzle to spray oxygen with the regulating quantity, and if the regulating quantity is negative, controlling the nozzle to spray preset gas with the absolute value of the regulating quantity so that the concentration of the oxygen in the SCR catalyst is in a corresponding preset range;

or if the regulating quantity is positive, controlling the nozzle to spray the preset gas with the regulating quantity, and if the regulating quantity is negative, controlling the nozzle to spray the oxygen with the absolute value of the regulating quantity, so that the concentration of the oxygen in the SCR catalyst is in a corresponding preset range.

In one possible implementation, the method further includes:

setting a plurality of groups of test working conditions, under each group of test working conditions, fixing the value of engine torque and the urea injection quantity of the SCR catalyst, changing the oxygen concentration, and obtaining NO of the SCR catalyst under each oxygen concentration _x And NH in the SCR catalyst outlet exhaust gas ₃ Obtaining a group of test results under each test working condition;

and determining a preset range corresponding to the concentration of oxygen in the SCR catalyst according to each group of test results.

In one possible implementation, the method further includes:

dividing the working temperature range of the SCR catalyst into n different temperature points, and dividing the NO at the inlet of the SCR catalyst _x The content range of the temperature sensor is divided into m different content points, n times m working condition points are formed by the n different temperature points and the m different content points, each working condition point corresponds to a group of working condition parameters, and the working condition parameters corresponding to every two working condition points are not identical;

sequentially obtaining the oxygen concentration at the inlet of the SCR catalyst corresponding to each working point;

acquiring a working point of which the oxygen concentration is not in the preset range as a working point of which the nozzle needs to be adjusted;

According to the oxygen concentration of each working point needing to be regulated on the nozzle, calculating the corresponding regulating quantity of each working point needing to be regulated on the nozzle;

and obtaining the adjustment table according to the working point required to be adjusted for the nozzle and the adjustment quantity corresponding to each working point required to be adjusted for the nozzle.

In one possible implementation, the operating condition parameters are a rotational speed and a torque of an engine in the engine exhaust aftertreatment system, the adjustment mechanism is the engine, the influence factor is a concentration of water vapor in an SCR catalyst, and the method includes:

judging whether the engine needs to be regulated according to the rotating speed, the torque and the regulating table of the engine under the current working condition;

if the engine needs to be regulated, determining regulating variables according to the regulating table, wherein the regulating variables comprise regulating variables of main fuel injection quantity and main fuel injection timing of the engine;

and adjusting the main injection quantity of the engine according to the main injection quantity, and adjusting the main injection timing of the engine according to the main injection timing adjustment quantity so that the concentration of the water vapor in the SCR catalyst is in a preset range corresponding to the water vapor concentration.

In one possible implementation, the method further includes:

the SCR catalyst pair NO when the condition containing water vapor is obtained _x A first curve of the conversion efficiency with temperature and the SCR catalyst for NO in the absence of water vapor _x A second curve of conversion efficiency as a function of temperature;

according to the first curve and the second curve, determining a temperature demarcation value, when the temperature of the SCR catalyst is smaller than the temperature demarcation value, a preset range corresponding to the concentration of water vapor in the SCR catalyst is a first preset range, the first preset range is smaller than or equal to a first percentage, when the temperature of the SCR catalyst is larger than or equal to the temperature demarcation value, a preset range corresponding to the concentration of water vapor in the SCR catalyst is a second preset range, the second preset range is larger than or equal to a second percentage and smaller than or equal to a third percentage, the first percentage is smaller than the second percentage, and the second percentage is smaller than the third percentage.

In one possible implementation, the method further includes:

dividing the rotating speed range of the engine into a different rotating speed points, dividing the torque range of the engine into b different torque points, wherein a times b working condition points are formed by the a different rotating speed points and the b different torque points, each working condition point corresponds to one group of working condition parameters, and each two groups of working condition parameters are not identical;

Sequentially acquiring the water vapor concentration of the SCR catalyst corresponding to each working point;

according to the rotating speed and the torque of the engine, determining an operating point of which the temperature of the SCR catalyst is smaller than the temperature demarcation value from the operating points a and b as a low-temperature operating point, wherein other operating points of the operating points a and b are operating points of which the temperature of the SCR catalyst is larger than or equal to the temperature demarcation value and are used as high-temperature operating points;

acquiring a working point with the water vapor concentration not in the first preset range from the low-temperature working point and acquiring a working point with the water vapor concentration not in the second preset range from the high-temperature working point as a working point required to be regulated for the engine;

calculating the adjustment quantity of the main injection quantity and the adjustment quantity of the main injection timing of the engine corresponding to each working point needing to be adjusted according to the water vapor concentration of each working point needing to be adjusted;

and obtaining the regulating table according to the operating point required to be regulated on the engine and the regulating quantity of the main injection quantity and the regulating quantity of the main injection timing of the engine corresponding to each operating point required to be regulated on the engine.

In one possible implementation, if the adjustment of the adjustment mechanism of the engine exhaust aftertreatment system is required, determining the adjustment amount according to the adjustment table includes:

acquiring a reference working condition point of the current working condition and an adjustment quantity corresponding to each reference working condition point in the adjustment table according to the working condition parameters of the current working condition;

and calculating the adjustment quantity corresponding to the current working condition through a linear difference algorithm according to the value of the working condition parameter of the current working condition, the value of the working condition parameter of each reference working condition point and the adjustment quantity corresponding to each reference working condition point.

In a second aspect, an embodiment of the present invention provides an engine nox emission control device, including: the device comprises a judging module, a determining module and an adjusting module;

the judging module is used for judging whether an adjusting mechanism of the engine exhaust aftertreatment system needs to be adjusted according to working condition parameters of the current working condition of the engine exhaust aftertreatment system and a preset adjusting table, the adjusting table comprises a plurality of working condition points, each working condition point corresponds to one group of working condition parameters, every two groups of working condition parameters are not identical, and the adjusting table comprises working condition points which need to be adjusted for the adjusting mechanism;

The determining module is configured to determine an adjustment amount according to the adjustment table if an adjustment is required to be performed on an adjustment mechanism of the exhaust aftertreatment system of the engine, where the adjustment table further includes an adjustment amount corresponding to each of the plurality of operating points that is required to be adjusted on the adjustment mechanism;

the adjusting module is used for adjusting the adjusting mechanism according to the adjusting quantity so that the value of an influence factor affecting the exhaust aftertreatment system of the engine on the conversion efficiency of the nitrogen oxides is in a preset range.

In a third aspect, an embodiment of the present invention provides a control device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the method according to the first aspect or any one of the possible implementations of the first aspect when the computer program is executed.

In a fourth aspect, embodiments of the present invention provide a computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the method as described above in the first aspect or any one of the possible implementations of the first aspect.

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

according to the invention, whether the current working condition of the engine exhaust aftertreatment system is the working condition requiring adjustment of the adjusting mechanism is judged in real time through the preset adjusting table, if yes, the adjusting amount requiring adjustment is judged according to the adjusting table, and the adjusting mechanism is adjusted according to the adjusting amount, so that the value of an influence factor influencing the conversion efficiency of the engine exhaust aftertreatment system to the nitrogen oxides is within a preset range, and the conversion efficiency of the engine exhaust aftertreatment system to the nitrogen oxides is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart illustrating an implementation of a method for controlling emissions of nitrogen oxides from an engine according to an embodiment of the present invention;

FIG. 2 is a flow chart illustrating another engine NOx emission control method according to an embodiment of the present invention;

FIG. 3a is a graph showing NO under high load conditions according to an embodiment of the present invention _x Conversion efficiency and NH in SCR catalyst outlet exhaust ₃ A graph of emissions as a function of oxygen concentration;

FIG. 3b is the present inventionNO under high load conditions provided by the illustrative embodiments _x Conversion efficiency and NH in SCR catalyst outlet exhaust ₃ A graph of emissions as a function of oxygen concentration;

FIG. 4 is a flowchart illustrating another engine NOx emission control method according to an embodiment of the present invention;

FIG. 5 is a graph of SCR catalyst versus NO for the case of water vapor _x The conversion efficiency of the SCR catalyst for NO in the absence of water vapor _x A schematic representation of a second curve of conversion efficiency as a function of temperature;

FIG. 6 is NO in exhaust _x In the case of (1) H ₂ O, no H ₂ NH under O condition ₃ By O ₂ Direct oxidation to NO _x Is a test result of (a);

FIG. 7 is a schematic diagram of an engine NOx emission control device according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a control device according to an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the following description will be made by way of specific embodiments with reference to the accompanying drawings.

Referring to fig. 1, a flowchart for implementing the method for controlling emission of nitrogen oxides in an engine according to an embodiment of the present invention is shown, and the details are as follows:

in step 101, according to the working condition parameters of the current working condition of the exhaust aftertreatment system of the engine and a preset adjustment table, judging whether an adjustment mechanism of the exhaust aftertreatment system of the engine is required to be adjusted, wherein the adjustment table comprises a plurality of working condition points, each working condition point corresponds to one group of working condition parameters, every two groups of working condition parameters are not identical, and the adjustment table comprises the working condition points which need to be adjusted for the adjustment mechanism.

In the embodiment of the invention, a plurality of working condition points are preset according to the working condition parameters of the exhaust aftertreatment system of the engine, the working condition points which need to be regulated by the regulating mechanism are obtained through means such as testing, and a regulating table is established. In an actual application scene, judging whether the current working condition is the working condition requiring to be regulated to the regulating mechanism according to the working condition parameters of the current working condition of the engine exhaust aftertreatment system.

In step 102, if an adjustment is required for an adjustment mechanism of an exhaust aftertreatment system of an engine, an adjustment amount is determined according to an adjustment table, where the adjustment table further includes an adjustment amount corresponding to each of a plurality of operating points for which the adjustment mechanism is required to be adjusted.

In the embodiment of the invention, if the current working condition is judged to be the working condition requiring the adjustment of the adjusting mechanism according to the step 101, the adjustment amount for adjusting the adjusting mechanism is determined according to the adjustment table.

In step 103, the adjusting mechanism is adjusted according to the adjustment amount, so that the concentration value of the influence factor affecting the conversion efficiency of the nitrogen oxide by the exhaust gas aftertreatment system of the engine is within a preset range.

In the embodiment of the invention, the adjusting mechanism is adjusted according to the adjusting quantity, so that the value of the influence factor influencing the conversion efficiency of the nitrogen oxide by the exhaust gas aftertreatment system of the engine is within a preset range.

Various influencing factors for influencing the conversion efficiency of the nitrogen oxides of the exhaust aftertreatment system of the engine, such as the content of oxygen in the SCR catalyst or the content of water vapor in the SCR catalyst, are available, and the conversion efficiency of the SCR catalyst to the nitrogen oxides is highest when the content or the concentration of any type of influencing factor is within a certain range. By the method provided by the embodiment of the invention, if the influence factor is the concentration of oxygen in the SCR catalyst, and the influence factor is controlled in an optimal range interval of the influence factor in real time, so that the conversion efficiency of the SCR catalyst on nitrogen oxides is improved.

In some embodiments, the operating point corresponding to the current operating condition is one of a plurality of operating points in the adjustment table, and the adjustment amount of the current operating condition is directly obtained according to the adjustment table.

In some embodiments, if the plurality of working condition points in the adjustment table do not include the current working condition, acquiring a reference working condition point of the current working condition and adjustment amounts corresponding to each reference working condition point in a preset adjustment table according to working condition parameters of the current working condition; and calculating the adjustment quantity corresponding to the current working condition through a linear difference algorithm according to the value of the working condition parameter of the current working condition, the value of the working condition parameter of each reference working condition point and the adjustment quantity corresponding to each reference working condition point.

In a possible implementation manner, the influence factor in the method embodiment corresponding to fig. 1 is the concentration of oxygen in the SCR catalyst, and in combination with fig. 2, the embodiment of the invention further provides a method for controlling emission of nitrogen oxides from an engine, when the concentration of oxygen in the SCR catalyst is within a preset range, the conversion efficiency of the SCR catalyst to the nitrogen oxides is highest, and the method provided in the embodiment of the invention improves the conversion efficiency of the exhaust aftertreatment system of the engine to the nitrogen oxides by controlling the concentration of oxygen in the SCR catalyst within the preset range, that is, within an optimal working range, as follows in detail:

in step 201, according to the NO at the inlet of the SCR catalyst under the current working condition _x And (3) judging whether the nozzle needs to be regulated or not according to the content of the SCR catalyst, the temperature of the SCR catalyst and the regulation table.

In the embodiment of the invention, the working condition parameter is NO at the inlet of the SCR catalyst in the exhaust aftertreatment system of the engine _x The content of (2) and the temperature of the SCR catalyst, wherein a nozzle is arranged at the inlet of the SCR catalyst and is used for injecting oxygen or preset gas, the preset gas is gas which does not participate in chemical reaction in the SCR catalyst, the regulating mechanism is the nozzle, and the influencing factor is the concentration of oxygen in the SCR catalyst.

In one possible implementation, the preset gas is nitrogen.

In the embodiment of the invention, first, a preset range corresponding to the oxygen concentration is determined by the following method:

setting a plurality of groups of test working conditions, under each group of test working conditions, fixing the value of the engine torque and the urea injection quantity of the SCR catalyst, changing the oxygen concentration, and obtaining NO of the SCR catalyst under each oxygen concentration _x Conversion efficiency of (c) and NH in SCR catalyst outlet exhaust ₃ And obtaining a group of test results under each test working condition. And determining a preset range corresponding to the concentration of oxygen in the SCR catalyst according to each group of test results.

The main chemical reactions in SCR catalysts include:

medium speed SCR reaction: 4NH ₃ +4NO+O ₂ →4N ₂ +6H ₂ 0；

Fast SCR reaction: 2NH ₃ +NO+NO ₂ →2N ₂ +3H ₂ 0；

Slow SCR reaction: 4NH ₃ +2NO ₂ +O ₂ →3N ₂ +6H ₂ 0；

It can be seen that O ₂ As a main reactant of the SCR reaction, its content (concentration) directly affects the conversion efficiency of the SCR catalyst to nitrogen oxides.

In the examples of the present invention, the following tests were designed: at least two working conditions are set according to the magnitude of the engine torque, for example, a low-load working condition is set corresponding to the working condition of smaller engine torque, and a high-load working condition is set corresponding to the condition of larger engine torque.

At low levelUnder the load working condition, the urea injection quantity of the SCR catalyst is set to be 100mg/s, and O is changed ₂ Concentrations of 4%, 6%, 8%, 10% and 12%, respectively; based on the high-load working condition, the urea injection quantity of the SCR catalyst is set to be 500mg/s, and O is changed ₂ Concentrations of 4%, 6%, 8%, 10% and 12%, respectively, for NO _x The effect of conversion efficiency and NH3 emissions in the SCR catalyst outlet exhaust was tested and the results are shown in fig. 3a and 3 b.

As can be seen from a combination of fig. 3a and 3b, under two conditions, O ₂ NO when the concentration increases from 4% to 8% _x The conversion efficiency is obviously improved. But with O ₂ Further increase in concentration for NO _x The conversion efficiency is basically not affected. NO (NO) _x Conversion efficiency with O ₂ On the one hand, O is the cause of the increase in concentration ₂ The increase of the partial pressure facilitates the adsorption and transfer of oxygen molecules on the surface of the carrier, on the other hand O ₂ React with NO to generate NO ₂ More beneficial to NO _x Is reduced. When O is ₂ The concentration continues to increase, the adsorption of oxygen molecules on the active sites of the catalyst has reached saturation, O ₂ Concentration vs. NO _x The effect of conversion efficiency is essentially negligible.

NH in SCR catalyst outlet exhaust ₃ Does not change much in concentration, mainly because of O ₂ Is increased to accelerate NH ₃ Is particularly easy to generate secondary pollutant N under high temperature condition ₂ O. So to control O ₂ The content is 8 to 10 percent, and can reach better NO _x Conversion effect.

Therefore, for this engine exhaust aftertreatment system, the preset range of the concentration of oxygen in the SCR catalyst may be set to 8% to 10%. The preset range is the optimal concentration range.

The above process of determining the preset range of the SCR catalyst oxygen concentration needs to be separately tested for each engine exhaust aftertreatment system, and after the preset range of the SCR catalyst oxygen concentration of one engine exhaust aftertreatment system is obtained, the process can be used as a reference for other engine exhaust aftertreatment systems of the same model.

According to the embodiment of the invention, the preset range of the oxygen concentration in the SCR system is determined by setting a plurality of groups of test conditions, the preset range is the optimal range of the oxygen concentration in the SCR catalyst, when the oxygen concentration in the SCR catalyst is in the range, the conversion efficiency of the SCR catalyst to nitrogen oxides is highest, and the conversion efficiency of the SCR catalyst to nitrogen oxides is improved by controlling the oxygen concentration in the SCR catalyst in the range in real time.

In the embodiment of the invention, next, the adjustment table is determined by the following method:

Dividing the working temperature range of the SCR catalyst into n different temperature points, and dividing NO at the inlet of the SCR catalyst _x The content range of (2) is divided into m different content points, n different temperature points and m different content points form n times m working condition points, each working condition point corresponds to a group of working condition parameters, and the working condition parameters corresponding to every two working condition points are not identical.

In the embodiment of the invention, the working temperature range of the SCR catalyst is determined, for example, the range is 200 to 500 degrees celsius, and in some embodiments, the working temperature range of the SCR catalyst can be divided into n points according to a fixed step, for example, the n different temperature points are 200 degrees celsius, 250 degrees celsius and 300 degrees celsius and … … degrees celsius respectively according to the step of selecting the point according to 50 degrees celsius. In some embodiments, instead of a fixed step, typical temperature points may be selected, which is not limited by the embodiments of the present invention.

In an embodiment of the invention, NO at the inlet of the SCR catalyst is determined _x In the range of 50 to 500ppm, in some embodiments, NO may be added in fixed steps _x The content range of (c) is divided into m different content points, for example, the content points are selected according to the step length of 50ppm, in some embodiments, some typical content points may be selected according to the actual working condition instead of selecting the points according to the fixed step length, which is not limited by the embodiment of the present invention.

And sequentially acquiring the oxygen concentration at the inlet of the SCR catalyst corresponding to each working point.

Catalytic SCR in fixed step sizeOperating temperature range selection point for SCR catalyst and NO at inlet of SCR catalyst _x The content range of (2) is selected to obtain n times m working points as shown in the following table 1:

TABLE 1

And acquiring the working point of which the oxygen concentration is not in a preset range as the working point of which the nozzle needs to be adjusted.

The predetermined range of the SCR catalyst oxygen concentration is illustrated as 8% to 10%. The preset range includes 8% and 10%. And searching the working points of which the oxygen concentration is not in the preset range in the table 1, namely the working points of which the oxygen concentration is less than 8 percent and the working points of which the oxygen concentration is more than 10 percent, namely the working points of which the adjusting mechanism needs to be adjusted.

Such as the operating point corresponding to 50ppm and 200 deg.c, the operating point corresponding to 100ppm and 200 deg.c, the operating point corresponding to … … ppm and 500 deg.c, etc. in table 1.

And calculating the corresponding adjustment quantity of each working point needing to adjust the nozzle according to the oxygen concentration of each working point needing to adjust the nozzle. And obtaining an adjusting table according to the operating point for adjusting the nozzle and the adjusting quantity corresponding to each operating point for adjusting the nozzle.

In one possible implementation, a nozzle is provided at the inlet of the SCR catalyst, the nozzle being used for injecting oxygen or a preset gas, the preset gas being a gas which does not take part in the chemical reaction in the SCR catalyst, the regulating mechanism being a nozzle, the regulating amount being the amount of oxygen injected through the nozzle or the amount of preset gas injected through the nozzle.

In one possible implementation, the preset gas may be nitrogen. The nozzle is a nitrogen/oxygen nozzle, and the adjustment amount corresponding to the working point of the adjustment mechanism is adjusted according to the requirement, so that an adjustment table is obtained, and in the adjustment table, the value of the adjustment amount corresponding to the other working points except the working point of the adjustment mechanism is 0.

By the above method, the adjustment table shown in the following table 2 can be obtained:

TABLE 2

In the embodiment of the present invention, the above tables 1 and 2 together constitute the adjustment table in the embodiment of the present invention.

In step 202, if an adjustment is required to the nozzle, an adjustment amount is determined according to an adjustment table.

In one possible implementation, in combination with table 2, if the adjustment is positive, the nozzle is controlled to inject oxygen of the adjustment size, and if the adjustment is negative, the nozzle is controlled to inject preset gas of the absolute value of the adjustment size, so that the concentration of oxygen in the SCR catalyst is within a corresponding preset range.

For example, in the regulation table, a negative value indicates nitrogen gas ejected from the nozzle, and a positive value indicates oxygen gas ejected from the nozzle.

If 50ppm of the working point is used, the value of the regulating variable of the working point corresponding to 200 ℃ is 4.5%, which represents that 4.5% of oxygen is sprayed out of the nozzle, and the concentration of oxygen in the SCR catalyst is in the optimal range by controlling the nozzle to spray 4.5% of oxygen, the value of the regulating variable of the working point corresponding to 250ppm and 500 ℃ is-1.5%, which represents that 1.5% of nitrogen is sprayed out of the nozzle. At the operating point, 1.5% of nitrogen is sprayed out by controlling the nozzle, so that the concentration of oxygen in the SCR catalyst is in an optimal range.

Of course, the above arrangement of table 2 is only one possible implementation, and may be set as follows: if the regulating quantity is positive, the nozzle is controlled to spray the preset gas with the regulating quantity, and if the regulating quantity is negative, the nozzle is controlled to spray the oxygen with the absolute value of the regulating quantity, so that the concentration of the oxygen in the SCR catalyst is in a corresponding preset range. The embodiment of the present invention is not limited thereto.

In step 203, the nozzle is adjusted according to the adjustment amount, and the nozzle is controlled to spray oxygen or a preset gas with the absolute value of the adjustment amount, so that the concentration of oxygen in the SCR catalyst is within a preset range corresponding to the oxygen concentration.

According to the embodiment of the invention, the operating point with the oxygen concentration not in the preset range is obtained, the value of the regulating quantity of the regulating nozzle corresponding to the operating point is calculated according to the oxygen concentration of the operating point, the regulating table is set, the regulating quantity required to be regulated in the current operating condition is determined by looking up the regulating table, and the spraying group is regulated to spray oxygen or nitrogen according to the regulating quantity, so that the oxygen concentration in the SCR catalyst is in the preset range, and the oxygen is in the concentration range which is the optimal concentration range of the oxygen, so that the conversion efficiency of the SCR on the nitrogen oxides is highest.

In a possible implementation manner, the influencing factor is the concentration of water vapor in the SCR catalyst, fig. 4 shows an implementation flow of an engine nitrogen oxide emission control method provided by the embodiment of the present invention, when the concentration of water vapor in the SCR catalyst is within a preset range, the conversion efficiency of the SCR catalyst to nitrogen oxides is the highest, and the method provided by the embodiment of the present invention improves the conversion efficiency of the engine exhaust aftertreatment system to nitrogen oxides by controlling the concentration of water vapor in the SCR catalyst within the preset range, that is, within an optimal working range, as follows in detail:

in step 401, it is determined whether the engine needs to be regulated according to the rotation speed, torque and regulation table of the engine under the current working condition.

In the embodiment of the invention, the working condition parameters are the rotating speed and the torque of the engine in the exhaust aftertreatment system of the engine, the regulating mechanism is the engine, and the influencing factor is the concentration of water vapor in the SCR catalyst.

In the embodiment of the invention, firstly, a preset range corresponding to the water vapor in the SCR catalyst is determined by the following method.

SCR catalyst pair NO when obtaining water vapor containing condition _x The conversion efficiency of (a) is a first curve of the conversion efficiency with temperature and the SCR catalyst is free of water vaporFor NO _x A second curve of conversion efficiency with temperature.

The first curve and the second curve are shown in fig. 5, and fig. 5 shows the influence of water vapor at 150-550 ℃ on the activity of the SCR catalyst. It can be seen that the presence of water vapor at low temperature reduces the denitration activity of the catalyst, the water vapor has a certain inhibiting effect on the SCR catalyst activity of the catalyst at the reaction temperature below 360 ℃, and the presence of water vapor weakens NH at higher temperature ₃ By O ₂ Direct oxidation to NO _x Thereby indirectly improving NO _x Conversion rate. FIG. 7 illustrates NO in the exhaust of an exhaust aftertreatment system _x In the case of (1) H ₂ O, no H ₂ NH under O condition ₃ By O ₂ Direct oxidation to NO _x Is a test result of (a). It can be seen that at temperatures below 550℃, H ₂ The presence of O to NH ₃ Direct oxidation to NO _x Has inhibiting effect.

Referring to FIG. 6, the presence of water vapor may reduce or increase the NO to some extent in the SCR system _x Is a transformation effect of (a).

And determining a temperature demarcation value according to the first curve and the second curve, wherein when the temperature of the SCR catalyst is smaller than the temperature demarcation value, the preset range corresponding to the concentration of the water vapor in the SCR catalyst is a first preset range, the first preset range is smaller than or equal to a first percentage, and when the temperature of the SCR catalyst is larger than or equal to the temperature demarcation value, the preset range corresponding to the concentration of the water vapor in the SCR catalyst is a second preset range.

The second preset range is equal to or greater than the second percentage and equal to or less than the third percentage, the first percentage is less than the second percentage, and the second percentage is less than the third percentage.

According to the first curve and the second curve, 360 ℃ can be set as a temperature demarcation value. For each engine, the temperature demarcation value corresponding to the exhaust gas aftertreatment system of the engine needs to be obtained through testing alone.

The invention uses the SCR catalyst to treat NO when the condition containing water vapor is obtained _x First of the conversion efficiency with temperatureCurve, and SCR catalyst vs. NO without water vapor _x According to the first curve and the second curve, determining a temperature demarcation value corresponding to the exhaust aftertreatment system of the engine, wherein for working conditions of which the temperature is smaller than the temperature demarcation value, a preset range corresponding to the concentration of water vapor in the SCR catalyst is a first preset range, the first preset range is smaller than or equal to a first percentage, and when the temperature of the SCR catalyst is larger than or equal to the temperature demarcation value, the preset range corresponding to the concentration of water vapor in the SCR catalyst is a second preset range. The concentration of the water vapor in the current working condition is in a corresponding preset range by judging the current working condition, so that the conversion efficiency of the SCR catalyst to nitrogen oxides is improved.

dividing the rotating speed range of the engine into a different rotating speed points, dividing the torque range of the engine into b different torque points, wherein a different rotating speed points and b different torque points form a multiplied by b working condition points, each working condition point corresponds to one group of working condition parameters, and each two groups of working condition parameters are not identical.

Selecting the rotating speed of the engine, for example, the range is 1200 rpm-2800 rpm, and the step length is 400rpm; selecting points for engine torque: such as 50 Nm-300 Nm, and a step size of 50Nm. In some embodiments, the points may not be selected according to a fixed step, which is not limited by the embodiment of the present invention.

And sequentially acquiring the water vapor concentration of the SCR catalyst corresponding to each working point.

The water vapor concentration of the SCR catalyst corresponding to each operating point is obtained as shown in the following table 3

TABLE 3 Table 3

50Nm

100Nm

150Nm

200Nm

250Nm

300Nm

1200rpm

1.6％

2.2％

4.4％

5.6％

6.7％

8.2％

1600rpm

1％

1.8％

3.2％

5.9％

7.1％

8.7％

2000rpm

1.3％

2.4％

3.8％

6.1％

7.5％

9.1％

2400rpm

1.8％

3.8％

4.1％

6.9％

7.9％

9.2％

2800rpm

3.7％

4.4％

5.9％

7.6％

8.1％

8.8％

And according to the rotating speed and the torque of the engine, determining an operating point of which the temperature of the SCR catalyst is less than the temperature demarcation value from among the operating points a multiplied by b as a low-temperature operating point, wherein other operating points of the operating points a multiplied by b are operating points of which the temperature of the SCR catalyst is less than the temperature demarcation value, and taking the operating points as high-temperature operating points.

The temperature of the SCR catalyst can be determined according to the engine speed and torque, and therefore, the operating point smaller than the temperature demarcation value and the operating point with the temperature larger than or equal to the temperature demarcation value are determined in the plurality of operating points according to the temperature demarcation value.

And acquiring the working point of which the water vapor concentration is not in a first preset range from the low-temperature working point and the working point of which the water vapor concentration is not in a second preset range from the high-temperature working point as the working points required to be adjusted.

Taking the temperature demarcation value of 360 ℃ as an example, assuming that the working condition points corresponding to the torques 50Nm, 100Nm and 150Nm in the table 3 are low-temperature working condition points and the other working condition points are high-temperature working condition points by the engine torque and the rotating speed, and assuming that the first preset range is less than or equal to 2% and the second preset range is more than or equal to 6% and less than or equal to 8%, according to the table 3, working condition points which are not in the corresponding preset range, such as the working condition points of 50Nm and 2800rpm, belong to the low-temperature working condition points and the corresponding water vapor concentration range is less than or equal to 2%, but the measured value is 3.7% and exceeds the corresponding concentration range.

And calculating the adjustment quantity of the main injection quantity and the adjustment quantity of the main injection timing of the engine corresponding to each working point needing to be adjusted according to the water vapor concentration of each working point needing to be adjusted. And obtaining an adjusting table according to the operating point required to be adjusted for the engine and the main injection quantity adjusting quantity and the main injection timing adjusting quantity of the engine corresponding to each operating point required to be adjusted for the engine.

In one possible implementation manner, the adjusting mechanism is an engine, the adjusting quantity is a main oil injection quantity and a main injection time of the engine, the adjusting quantity corresponding to a working point where the adjusting mechanism is adjusted according to needs is obtained, the adjusting table comprises an adjusting table where the main oil injection quantity is adjusted and an adjusting table where the main injection time is adjusted, in the adjusting table where the main oil injection quantity is adjusted, each working point where the adjusting mechanism is required to be adjusted corresponds to the adjusting quantity of the main oil injection quantity of the working point, and in the adjusting table where the main injection time is adjusted, each working point where the adjusting mechanism is required to be adjusted corresponds to the adjusting quantity of the main injection time of the working point.

The adjustment table for adjusting the main injection amount is shown in the following table 4

TABLE 4 Table 4

Main fuel injection quantity	50Nm	100Nm	150Nm	200Nm	250Nm	300Nm
							1200rpm	0	5.791	6.1322	4.119	0	1.078
1600rpm	0	0	6.944	5.34	0	1.367
							2000rpm	0	2.4554	5.1655	0	0	2.8754
2400rpm	0	2.4664	2.9989	0	0	3.9001
							2800rpm	3.8751	1.6248	1.905	0	1.668	1.9030

The adjustment table for adjusting the main injection timing is shown in table 5 below

TABLE 5

Timing of main injection	50Nm	100Nm	150Nm	200Nm	250Nm	300Nm
							1200rpm	0	3.000	1.609	1.938	0	2.344
1600rpm	0	0	2.547	2.000	0	2.000
							2000rpm	0	1.984	1.859	0	0	1.080
2400rpm	0	1.625	1.547	0	0	1.297
							2800rpm	1.297	1.203	1.000	0	1.125	2.000

In the present embodiment, the adjustment table is composed of tables 3, 4 and 5 together.

In step 402, if an adjustment is required to the engine, an adjustment amount is determined according to an adjustment table, where the adjustment amount includes an adjustment amount of a main injection amount of the engine and an adjustment amount of a main injection timing.

In step 403, the main injection amount of the engine is adjusted according to the adjustment amount of the main injection amount, and the main injection timing of the engine is adjusted according to the adjustment amount of the main injection timing, so that the concentration of the water vapor in the SCR catalyst is within a preset range corresponding to the water vapor concentration.

According to the embodiment of the invention, the operating point with the water vapor concentration not in the preset range is obtained, the value of the regulating variable of the engine corresponding to the operating point is calculated according to the water vapor concentration of the operating point, the regulating table is set, the regulating variable which needs to be regulated in the current operating condition is determined by searching the regulating table, and the main fuel injection quantity and the main fuel injection timing of the engine are regulated according to the regulating variable, so that the water vapor concentration in the SCR catalyst is in the preset range corresponding to the current operating condition, and the water vapor is in the optimal concentration range of the water vapor, so that the conversion efficiency of the SCR on nitrogen oxides is highest in the concentration range.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.

The following are device embodiments of the invention, for details not described in detail therein, reference may be made to the corresponding method embodiments described above.

Fig. 7 is a schematic structural diagram of an engine nox emission control device according to an embodiment of the present invention, and for convenience of explanation, only a portion related to the embodiment of the present invention is shown, and the details are as follows:

as shown in fig. 7, the engine nox emission control device 7 includes: a judging module 71, a determining module 72 and an adjusting module 73;

the judging module 71 is configured to judge whether an adjustment mechanism of the exhaust aftertreatment system of the engine is required to be adjusted according to a working condition parameter of a current working condition of the exhaust aftertreatment system of the engine and a preset adjustment table, where the adjustment table includes a plurality of working condition points, each working condition point corresponds to a group of working condition parameters, each two groups of working condition parameters are not identical, and the adjustment table includes working condition points that need to be adjusted for the adjustment mechanism;

The determining module 72 is configured to determine an adjustment amount according to an adjustment table if an adjustment of an adjustment mechanism of the exhaust aftertreatment system of the engine is required, where the adjustment table further includes an adjustment amount corresponding to each of a plurality of operating points that require adjustment of the adjustment mechanism;

the adjusting module 73 is configured to adjust the adjusting mechanism according to the adjustment amount, so that a value of an influence factor affecting the exhaust aftertreatment system of the engine on the conversion efficiency of the nitrogen oxide is within a preset range.

In one possible implementation, the operating parameter is NO at the inlet of the SCR catalyst in the engine exhaust aftertreatment system _x The content of (2) and the temperature of the SCR catalyst, wherein a nozzle is arranged at the inlet of the SCR catalyst and is used for injecting oxygen or preset gas, the preset gas is gas which does not participate in chemical reaction in the SCR catalyst, the regulating mechanism is the nozzle, and the influencing factor is the concentration of oxygen in the SCR catalyst;

A judging module 71 for judging NO at the inlet of the SCR catalyst according to the current working condition _x Judging whether the nozzle needs to be regulated or not according to the content of the SCR catalyst, the temperature of the SCR catalyst and the regulation table;

a determining module 72, configured to determine an adjustment amount according to an adjustment table if the nozzle needs to be adjusted;

the adjusting module 73 is configured to adjust the nozzle according to the adjustment amount, and control the nozzle to spray oxygen or a preset gas with an absolute value of the adjustment amount, so that the concentration of oxygen in the SCR catalyst is within a preset range corresponding to the oxygen concentration.

In one possible implementation, the adjustment module 73 is further configured to:

or if the regulating quantity is positive, controlling the nozzle to spray the preset gas with the regulating quantity, and if the regulating quantity is negative, controlling the nozzle to spray the oxygen with the absolute value of the regulating quantity so as to ensure that the concentration of the oxygen in the SCR catalyst is in a corresponding preset range.

In one possible implementation, the determining module 72 is further configured to:

Setting a plurality of groups of test working conditions, under each group of test working conditions, fixing the value of the engine torque and the urea injection quantity of the SCR catalyst, changing the oxygen concentration, and obtaining NO of the SCR catalyst under each oxygen concentration _x Conversion efficiency of (c) and NH in SCR catalyst outlet exhaust ₃ Obtaining a group of test results under each test working condition;

dividing the working temperature range of the SCR catalyst into n different temperature points, and dividing NO at the inlet of the SCR catalyst _x The content range of the temperature sensor is divided into m different content points, n different temperature points and m different content points form n times m working condition points, each working condition point corresponds to a group of working condition parameters, and the working condition parameters corresponding to every two working condition points are not completely identical;

acquiring a working point of which the oxygen concentration is not in a preset range as a working point of which the nozzle needs to be adjusted;

And obtaining an adjusting table according to the operating point for adjusting the nozzle and the adjusting quantity corresponding to each operating point for adjusting the nozzle.

In one possible implementation, the operating mode parameters are the rotational speed and torque of the engine in the exhaust aftertreatment system of the engine, the adjusting mechanism is the engine, and the influencing factor is the concentration of water vapor in the SCR catalyst;

the judging module 71 is further configured to: judging whether the engine needs to be regulated according to the rotating speed, the torque and the regulating table of the engine under the current working condition;

the determination module 72 is also configured to: if the engine needs to be regulated, determining regulating variables according to a regulating table, wherein the regulating variables comprise regulating variables of main fuel injection quantity and main fuel injection timing of the engine;

the adjustment module 73 is also for: and adjusting the main fuel injection quantity of the engine according to the main fuel injection quantity, and adjusting the main fuel injection timing of the engine according to the main fuel injection timing so that the concentration of the water vapor in the SCR catalyst is in a preset range corresponding to the water vapor concentration.

SCR catalyst pair NO when obtaining water vapor containing condition _x The conversion efficiency of the SCR catalyst for NO in the absence of water vapor _x A second curve of conversion efficiency as a function of temperature;

according to the first curve and the second curve, determining a temperature demarcation value, when the temperature of the SCR catalyst is smaller than the temperature demarcation value, the preset range corresponding to the concentration of the water vapor in the SCR catalyst is a first preset range, the first preset range is smaller than or equal to a first percentage, when the temperature of the SCR catalyst is larger than or equal to the temperature demarcation value, the preset range corresponding to the concentration of the water vapor in the SCR catalyst is a second preset range, the second preset range is larger than or equal to a second percentage and smaller than or equal to a third percentage, the first percentage is smaller than the second percentage, and the second percentage is smaller than the third percentage.

dividing the rotating speed range of the engine into a different rotating speed points, dividing the torque range of the engine into b different torque points, wherein a times b working condition points are formed by the a different rotating speed points and the b different torque points, each working condition point corresponds to one group of working condition parameters, and each two groups of working condition parameters are not completely identical;

sequentially obtaining the water vapor concentration of the SCR catalyst corresponding to each working point;

according to the rotating speed and torque of the engine, determining an operating point of which the temperature of the SCR catalyst is smaller than a temperature demarcation value from among a times b operating points as a low-temperature operating point, wherein other operating points of the a times b operating points are operating points of which the temperature of the SCR catalyst is greater than or equal to the temperature demarcation value and are used as high-temperature operating points;

Acquiring a working point with the water vapor concentration not in a first preset range from the low-temperature working point and acquiring a working point with the water vapor concentration not in a second preset range from the high-temperature working point as the working point required to be regulated;

according to the water vapor concentration of each working point needing to be regulated on the engine, calculating the regulating quantity of the main fuel injection quantity and the regulating quantity of the main fuel injection timing of the engine corresponding to each working point needing to be regulated on the engine;

and obtaining an adjusting table according to the operating point required to be adjusted for the engine and the main injection quantity adjusting quantity and the main injection timing adjusting quantity of the engine corresponding to each operating point required to be adjusted for the engine.

according to the working condition parameters of the current working condition, a reference working condition point of the current working condition and an adjustment quantity corresponding to each reference working condition point are obtained in an adjustment table;

The engine nox emission control device provided in this embodiment may be used to implement the above embodiment of the engine nox emission control method, and its implementation principle and technical effects are similar, and this embodiment will not be described here again.

Fig. 8 is a schematic diagram of a control device according to an embodiment of the present invention. As shown in fig. 8, the control device 8 of this embodiment includes: a processor 80, a memory 81 and a computer program 82 stored in the memory 81 and executable on the processor 80. The processor 80, when executing the computer program 82, implements the steps of the various engine nox emission control method embodiments described above, such as steps 101 through 103 shown in fig. 1. Alternatively, the processor 80, when executing the computer program 82, performs the functions of the modules/units of the apparatus embodiments described above, such as the functions of the units 71 to 73 shown in fig. 7.

By way of example, the computer program 82 may be partitioned into one or more modules/units that are stored in the memory 81 and executed by the processor 80 to complete the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing the specified functions, which instruction segments are used to describe the execution of the computer program 82 in the control means 8.

The control device 8 may be an engine ECU (Electronic Control Unit ). The control device 8 may include, but is not limited to, a processor 80, a memory 81. It will be appreciated by those skilled in the art that fig. 8 is merely an example of the control device 8 and does not constitute a limitation of the control device 8, and may include more or less components than illustrated, or may combine certain components, or different components, e.g., the control device may further include an input-output device, a network access device, a bus, etc.

The processor 80 may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 81 may be an internal storage unit of the control device 8, such as a hard disk or a memory of the control device 8. The memory 81 may be an external storage device of the control apparatus 8, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided in the control apparatus 8. Further, the memory 81 may also include both an internal memory unit and an external memory device of the control device 8. The memory 81 is used for storing the computer program and other programs and data required by the control device. The memory 81 may also be used to temporarily store data that has been output or is to be output.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment 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, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/control apparatus and method may be implemented in other manners. For example, the apparatus/control apparatus embodiments described above are merely illustrative, e.g., the division of the modules or units is merely a logical function division, and there may be additional divisions in actual implementation, e.g., multiple units or components may be combined or 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 may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network 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 modules/units, 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 present invention may be implemented in whole or in part by a computer program to instruct related hardware, and the computer program may be stored in a computer readable storage medium, where the computer program, when executed by a processor, may implement the steps of the above-described embodiments of the method for controlling emission of nitrogen oxides from an engine. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium may include content that is subject to appropriate increases and decreases as required by jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is not included as electrical carrier signals and telecommunication signals.

The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.

Claims

1. A method for controlling emissions of nitrogen oxides from an engine, comprising:

2. The method of claim 1, wherein the operating condition parameter is NO at an inlet of an SCR catalyst in the engine exhaust aftertreatment system _x A nozzle is arranged at an inlet of the SCR catalyst, the nozzle is used for injecting oxygen or preset gas, the preset gas is gas which does not participate in chemical reaction in the SCR catalyst, the regulating mechanism is the nozzle, the influencing factor is the concentration of oxygen in the SCR catalyst, and the method comprises the following steps:

3. The method according to claim 2, wherein adjusting the nozzle according to the adjustment amount, controlling the nozzle to inject oxygen or a preset gas of an absolute value of the adjustment amount, such that the concentration of oxygen in the SCR catalyst is within a corresponding preset range includes:

4. A method according to claim 2 or 3, characterized in that the method further comprises:

5. The method of claim 4, further comprising:

6. The method of claim 1, wherein the operating parameters are a rotational speed and a torque of an engine in the engine exhaust aftertreatment system, the adjustment mechanism is the engine, the impact factor is a concentration of water vapor in an SCR catalyst, the method comprising:

7. The method of claim 6, wherein the method further comprises:

8. The method of claim 7, wherein the method further comprises:

9. The method of any one of claims 1 to 8, wherein if an adjustment of an adjustment mechanism of the engine exhaust aftertreatment system is desired, determining an adjustment amount based on the adjustment table comprises:

10. An engine nitrogen oxide emission control device, comprising: the device comprises a judging module, a determining module and an adjusting module;

11. A control device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of the preceding claims 1 to 9 when the computer program is executed.

12. A computer readable storage medium storing a computer program, characterized in that the computer program when executed by a processor implements the steps of the method according to any of the preceding claims 1 to 9.