CN114135376B

CN114135376B - Double-nozzle urea crystallization control method and exhaust gas aftertreatment system

Info

Publication number: CN114135376B
Application number: CN202111283823.6A
Authority: CN
Inventors: 张娟; 张军; 闫立冰; 王震华; 赵杰
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: 2021-11-01
Filing date: 2021-11-01
Publication date: 2023-01-06
Anticipated expiration: 2041-11-01
Also published as: CN114135376A

Abstract

The application discloses a double-nozzle urea crystallization control method and an exhaust gas post-treatment system, wherein the operating parameters of the exhaust gas treatment system are monitored; when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold value and not lower than a second preset threshold value, judging whether a preset execution condition of first coordination processing is met or not; if the preset execution condition of the first coordination processing is established, carrying out the first coordination processing on the injection of the first nozzle and the second nozzle; the first coordination process is for increasing the injection quantity of at least one of the first nozzle and the second nozzle in accordance with the first nozzle target injection quantity, the first nozzle actual injection quantity, the second nozzle target injection quantity, and the second nozzle actual injection quantity included in the operation parameters. The method is based on monitoring of the overall NOx conversion efficiency, the CCSCR urea injection amount and the SCR urea injection amount are controlled in a coordinated mode, and the urea crystallization amount is controlled to be a lower level while the overall NOx conversion efficiency is optimized.

Description

Double-nozzle urea crystallization control method and exhaust gas aftertreatment system

Technical Field

The application relates to the technical field of automotive electronics, in particular to a dual-nozzle urea crystallization control method and an exhaust gas aftertreatment system.

Background

With the increasing strictness of automotive emissions regulations, aftertreatment systems with SCR (selective catalytic reduction) become the mainstream technology for reducing emissions. The aftertreatment system with the SCR achieves the purpose of reducing NOx (nitrogen oxide) by injecting urea into the SCR tank, thereby reducing emission and meeting the requirements of emission regulations.

For a dual-nozzle urea injection system, although the flexibility of urea injection control is improved due to the provision of two nozzles, in the existing SCR control, crystallization control is mainly performed through injection amount limit values preset by flow and temperature, the urea crystallization control is rough, and the urea crystallization amount is high.

Disclosure of Invention

The embodiment of the application provides a dual-nozzle urea crystallization control method and an exhaust gas aftertreatment system, which can coordinate and control the urea injection amount of a close coupled selective catalytic conversion (SCR) device and the urea injection amount of the SCR device based on monitoring the overall NOx conversion efficiency, and control the urea crystallization amount to a lower level while optimizing the overall NOx conversion efficiency.

In a first aspect, an embodiment of the present application provides a dual-nozzle urea crystallization control method, where the dual nozzles are a first nozzle and a second nozzle respectively installed before a ccSCR system and an SCR system, and the method includes:

monitoring operating parameters of the tail gas treatment system; the operation parameters comprise a first nozzle target injection quantity, a first nozzle actual injection quantity, a second nozzle target injection quantity, a second nozzle actual injection quantity and comprehensive NOx conversion efficiency corresponding to the ccSCR system and the SCR system;

when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold and not lower than a second preset threshold, judging whether a preset execution condition of first coordination processing is satisfied; the first coordination process is configured to increase an ejection amount of at least one of the first nozzle and the second nozzle in accordance with the first nozzle target ejection amount, the first nozzle actual ejection amount, the second nozzle target ejection amount, and the second nozzle actual ejection amount; the preset execution condition represents that at least one of the first nozzle and the second nozzle is limited in spraying;

and if the preset execution condition of the first coordination processing is satisfied, performing the first coordination processing on the injection of the first nozzle and the second nozzle.

The method comprises the steps of monitoring the operation parameters of the tail gas treatment system; when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold value and not lower than a second preset threshold value, judging whether a preset execution condition of first coordination processing is met or not; if the preset execution condition of the first coordination processing is met, performing the first coordination processing on the injection of the first nozzle and the second nozzle; the first coordination processing is used for increasing the injection quantity of at least one of the first nozzle and the second nozzle according to the target injection quantity of the first nozzle, the actual injection quantity of the first nozzle, the target injection quantity of the second nozzle and the actual injection quantity of the second nozzle which are included by the operation parameters; the preset execution condition indicates that at least one of the first nozzle and the second nozzle is limited in injection. The method is based on monitoring of the overall NOx conversion efficiency, the CCSCR urea injection amount and the SCR urea injection amount are controlled in a coordinated mode, and the urea crystallization amount is controlled to be a lower level while the overall NOx conversion efficiency is optimized.

In one possible implementation, the operating parameters further include a first nozzle injection limit, a second nozzle injection limit; the performing the first coordination process on the ejection of the first nozzle and the second nozzle includes:

if the target injection quantity of the first nozzle exceeds the injection limit value of the first nozzle and the target injection quantity of the second nozzle does not exceed the injection limit value of the second nozzle, assigning the actual injection quantity of the first nozzle as the injection limit value of the first nozzle, and increasing a first efficiency closed-loop correction quantity to the actual injection quantity of the second nozzle; the first efficiency closed-loop correction is obtained by performing difference calculation on the target injection quantity of the first nozzle and the injection limit value of the first nozzle, and the injection limit value of the second nozzle and the actual injection quantity of the second nozzle respectively, and selecting one of the two difference values with a smaller value if the two difference values are positive values; or the like, or, alternatively,

if the target injection quantity of the second nozzle exceeds the second nozzle injection limit value and the target injection quantity of the first nozzle does not exceed the first nozzle injection limit value, assigning the actual injection quantity of the second nozzle as the second nozzle injection limit value, and increasing a second efficiency closed-loop correction quantity to the actual injection quantity of the first nozzle; the second closed-loop efficiency correction is obtained by performing difference calculation on the target injection quantity of the second nozzle and the injection limit value of the second nozzle, and the injection limit value of the first nozzle and the actual injection quantity of the first nozzle respectively, and selecting one of the two difference values with a smaller value if the two difference values are positive values; or the like, or, alternatively,

and if the target injection quantity of the second nozzle exceeds the injection limit value of the second nozzle and the target injection quantity of the first nozzle exceeds the injection limit value of the first nozzle, assigning the actual injection quantity of the first nozzle as the injection limit value of the first nozzle and assigning the actual injection quantity of the second nozzle as the injection limit value of the second nozzle.

According to the method, the urea injection of the first nozzle and the second nozzle can be more finely regulated and controlled by performing coordinated treatment on the injection of the first nozzle and the second nozzle according to the comparison result of the target injection amount of the first nozzle and the injection limit value of the first nozzle and the comparison result of the target injection amount of the second nozzle and the injection limit value of the second nozzle, and the injection amount of at least one nozzle of the first nozzle and the second nozzle can be increased, so that the urea injection of the first nozzle and the second nozzle can be prevented from exceeding the injection limit value, and the urea crystallization amount can be further reduced.

In one possible implementation, the method further includes:

and when the comprehensive NOx conversion efficiency is monitored to be lower than a second preset threshold value, enabling the first nozzle and the second nozzle to respectively spray according to the target injection quantity of the first nozzle and the target injection quantity of the second nozzle.

According to the method, when the comprehensive NOx conversion efficiency is monitored to be lower than a second preset threshold value, the first nozzle and the second nozzle are respectively used for injecting according to the target injection quantity of the first nozzle and the target injection quantity of the second nozzle. The method can release the injection limit values of the two nozzles when the comprehensive conversion efficiency of the NOx is too low, and realize the improvement of the overall conversion efficiency of the NOx on the premise of controlling the urea crystal quantity to be a lower level on the whole.

In one possible implementation, the method further includes:

and when the comprehensive NOx conversion efficiency is not lower than a first preset threshold value, enabling the first nozzle and the second nozzle to respectively spray according to the actual injection quantity of the first nozzle and the actual injection quantity of the second nozzle.

According to the method, when the comprehensive NOx conversion efficiency is not lower than a first preset threshold value, the first nozzle and the second nozzle are respectively used for injecting according to the actual injection quantity of the first nozzle and the actual injection quantity of the second nozzle. According to the method, when the comprehensive NOx conversion efficiency is very high, the current injection states of the two nozzles are maintained, additional injection control is not performed, the urea crystal quantity is controlled to be lower on the whole, the high level of the comprehensive NOx conversion efficiency can be effectively guaranteed, and the accuracy and the high efficiency of the double-nozzle urea crystal control method are guaranteed.

In one possible implementation, the integrated NOx conversion efficiency is determined by a first NOx concentration value and a second NOx concentration value measured by a first NOx sensor upstream of the ccSCR system and a second NOx sensor downstream of the SCR system, respectively.

In the above method, the NOx integrated conversion efficiency is determined by a first NOx concentration value and a second NOx concentration value measured by a first NOx sensor upstream of the ccSCR system and a second NOx sensor downstream of the SCR system, respectively. The method can determine the comprehensive conversion efficiency of the NOx by smaller calculation amount, not only integrally controls the urea crystallization amount to be lower level, but also can efficiently ensure the high level of the comprehensive conversion efficiency of the NOx, and ensures the integral accuracy of the dual-nozzle urea crystallization control method.

In a possible implementation manner, the operation parameters further include a NOx comprehensive conversion efficiency change rate, a first temperature value of the ccSCR system, and a second temperature value of the SCR system; prior to the first coordinated processing of the ejection of the first nozzle and the second nozzle, the method further comprises:

if the change rate of the comprehensive NOx conversion efficiency is smaller than a third preset threshold value, determining a first nozzle over-limit injection limit value and a second nozzle over-limit injection limit value respectively corresponding to the first nozzle and the second nozzle according to a preset over-limit starting temperature range, the first temperature value and the second temperature value, and executing the following steps to carry out second coordination processing on the injection of the first nozzle and the second nozzle: if the first temperature value meets the over-limit starting temperature range and the second temperature value meets the over-limit starting temperature range, controlling the second nozzle to spray according to the over-limit spraying limit value of the second nozzle, and controlling the first nozzle to spray according to the over-limit spraying limit value of the first nozzle; alternatively, the first and second electrodes may be,

if the first temperature value is in accordance with the overrun starting temperature range and the second temperature value is not in accordance with the overrun starting temperature range, determining a continuous spraying limit value of the second nozzle, controlling the first nozzle to spray according to the overrun spraying limit value of the first nozzle, and controlling the first nozzle to spray according to the spraying limit value of the first nozzle and enabling the second nozzle to spray according to the continuous spraying limit value of the second nozzle when the fact that the overspray amount of the first nozzle exceeds the overspray amount limit value of the first nozzle is monitored; alternatively, the first and second electrodes may be,

if the second temperature value is in accordance with the overrun starting temperature range and the first temperature value is not in accordance with the overrun starting temperature range, determining a continuous spraying limit value of the first nozzle, controlling the second nozzle to spray according to the overrun spraying limit value of the second nozzle, and controlling the second nozzle to spray according to the spraying limit value of the second nozzle and enabling the first nozzle to spray according to the continuous spraying limit value of the first nozzle when the fact that the overspray amount of the second nozzle exceeds the overspray amount limit value of the second nozzle is monitored.

In the method, the third preset threshold may be a negative number (for example, an absolute value is less than 0.01) with a small absolute value, when the rate of change of the comprehensive NOx conversion efficiency is less than the third preset threshold and the comprehensive NOx conversion efficiency is at a general level and has a downward trend, it is determined whether to release the injection amount limit of the first nozzle or the second nozzle according to the first temperature value of the ccSCR system and the second temperature value of the SCR system, and the second coordination process is performed on the injection of the first nozzle and the second nozzle. The method can enable the nozzle meeting the over-limit injection condition to inject at the over-limit injection limit value of the nozzle higher than the injection limit value of the nozzle when the comprehensive NOx conversion efficiency is at a general level and has a descending trend, and simultaneously monitor the over-injection amount of the nozzle.

In one possible implementation manner, the controlling the first nozzle and the second nozzle to perform injection according to the first nozzle over-injection limit value, the second nozzle over-injection limit value, the first nozzle over-injection limit value, and the second nozzle over-injection limit value further includes:

and if the first temperature value and the second temperature value do not accord with the overrun starting temperature range, enabling the first nozzle and the second nozzle to spray according to the actual spraying quantity of the first nozzle and the actual spraying quantity of the second nozzle respectively.

In the method, if the first temperature value and the second temperature value do not conform to the overrun starting temperature range, the first nozzle and the second nozzle are respectively used for spraying according to the actual spraying amount of the first nozzle and the actual spraying amount of the second nozzle. According to the method, when the comprehensive NOx conversion efficiency is at a general level and has a descending trend, but no nozzle meeting the over-limit injection condition exists, the current injection states of the two nozzles are maintained, additional injection control is not performed, the calculated amount is reduced, the urea crystal amount is controlled to be lower on the whole, the improper control of the comprehensive NOx conversion efficiency can be prevented, and the whole efficiency of the double-nozzle urea crystal control method is ensured.

In one possible implementation, the method further includes:

determining a first accumulated over-spray amount and a second accumulated over-spray amount corresponding to the first nozzle and the second nozzle respectively;

determining a first nozzle crystallization amount and a second nozzle crystallization amount according to the first accumulated overspray amount and the second accumulated overspray amount;

and if the crystallization amount of the first nozzle or the crystallization amount of the second nozzle exceeds a preset crystallization limit value, performing crystallization regeneration heat treatment on the corresponding first nozzle or the corresponding second nozzle.

Determining a first accumulated over-spray amount and a second accumulated over-spray amount corresponding to the first nozzle and the second nozzle respectively; determining a first nozzle crystallization amount and a second nozzle crystallization amount according to the first accumulated overspray amount and the second accumulated overspray amount; and if the crystallization amount of the first nozzle or the crystallization amount of the second nozzle exceeds a preset crystallization limit value, performing crystallization regeneration heat treatment on the corresponding first nozzle or the corresponding second nozzle. The method can monitor the whole crystallization amount, timely triggers the crystallization regeneration heat treatment process through the preset crystallization limit, and controls the urea crystallization amount to be at a lower level while realizing the optimization of the overall NOx conversion efficiency.

In one possible implementation manner, the first temperature value is acquired from a first temperature sensor at the front end of the ccSCR system; the second temperature value is obtained from a second temperature sensor at the front end of the SCR system.

In the method, the first temperature value is obtained from a first temperature sensor at the front end of the ccSCR system; the second temperature value is obtained from a second temperature sensor at the front end of the SCR system. The method can accurately and efficiently obtain the temperature data of the CCSCR system and the SCR system, quickly determine whether the temperature data accords with the overrun starting temperature range, integrally control the urea crystallization amount to be at a lower level, efficiently ensure the high level of the comprehensive conversion efficiency of NOx, and ensure the high efficiency of the dual-nozzle urea crystallization control method.

In a second aspect, an embodiment of the present application provides an exhaust gas after-treatment system, where the exhaust gas after-treatment system includes a cccdoc system, a cccscr system, a DOC system, a DPF system, an SCR system, and an ASC system, which are sequentially communicated with an engine exhaust outlet through an exhaust pipe; a first nozzle is arranged between the ccSCR system and the ccDOC system; a second nozzle is arranged between the SCR system and the DPF system, and the exhaust gas after-treatment system is established according to the double-nozzle urea crystallization control method of any one of the first aspect.

In one possible implementation manner, the method further includes:

a first NOx sensor and a second NOx sensor disposed at an inlet of the CCDOC system and an outlet of the ASC system, respectively; a first temperature sensor and a second temperature sensor, the first temperature sensor disposed between the ccSCR system and the cccDOC system; the second temperature sensor is disposed between the DPF system and the SCR system.

The technical effect brought by any implementation manner in the second aspect may refer to the technical effect brought by the implementation manner in the first aspect, and is not described herein again.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of an exhaust aftertreatment system according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart of a dual nozzle urea crystallization control method according to an embodiment of the present disclosure;

FIG. 3 is a schematic flow chart of another dual nozzle urea crystallization control method provided in the embodiments of the present application;

FIG. 4 is a schematic structural diagram of a dual-nozzle urea crystallization control device according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of another dual-nozzle urea crystallization control device provided in the embodiments of the present application;

FIG. 6 is a schematic structural diagram of a third dual-nozzle urea crystallization control device provided in the embodiments of the present application;

FIG. 7 is a schematic structural diagram of a fourth dual-nozzle urea crystallization control device provided in the embodiments of the present application;

fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described in further detail with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Some terms in the embodiments of the present application are explained below to facilitate understanding by those skilled in the art.

(1) ECU (Electronic Control Unit): the ECU, also known as an "engine electronic control unit", is a controller that performs calculation, processing, and judgment according to signals input from various sensors, and then outputs commands to control the operation of an actuator.

(2) A rack: the bench is a test device for calibrating the engine and is used for calibrating various performance parameters of the engine, including the rotating speed of the engine, the torque of the engine, the fuel injection quantity, the emission and the like.

(3) ccSCR (close coupled selective catalytic conversion device): the ccSCR is a catalyst additionally arranged at the foremost end of an SCR (selective catalytic reduction) aftertreatment system, so that the heat in tail gas is fully utilized, the urea spray stopping time is shortened, and the NOx conversion efficiency of the aftertreatment system at low temperature is improved.

(4) SCR (selective catalytic reduction): the SCR is a catalyst additionally arranged behind the ccSCR and is a post-positioned selective catalytic conversion device, so that an effective means for reducing the emission of nitrogen oxides of the diesel engine by utilizing a selective catalytic reduction technology is provided. An aqueous solution of urea having a concentration of 32.5% is typically injected into the exhaust pipe, the urea decomposes at high temperature to produce ammonia gas, and NOx in the exhaust gas is reduced to nitrogen and water by the produced ammonia gas, thereby reducing NOx emissions.

(5) DPF (diesel particulate filter): when the amount of the trapped particulate matter reaches a certain degree, passive regeneration or active regeneration is needed, so that the trapping capacity of the DPF on the particulate matter is recovered.

(6) cccoc (close coupled diesel oxide catalyst): the cccDOC is used for converting NO in the tail gas into NO2 and assisting the normal work of the cccSCR.

(7) DOC (diesel oxide catalyst, oxidation catalytic converter): the oxidation catalytic converter can be arranged in front of the DPF and used for converting NO in the tail gas into NO2 through oxidation, and meanwhile, the temperature of the tail gas is increased, and the normal work of the DPF and the SCR is assisted.

(8) ASC (Ammonia Slip Catalyst, ammonia oxidation Catalyst): the ASC is one of diesel vehicle exhaust gas after-treatment devices, and is a device which is arranged at the rear end of an SCR (selective catalytic reduction) and reduces ammonia leaked out of exhaust gas at the rear end of the SCR through catalytic oxidation.

In order to reduce the urea crystallization amount of the dual-nozzle urea injection system, the embodiment of the application provides a dual-nozzle urea crystallization control method and an exhaust gas after-treatment system. In order to better understand the technical solution provided by the embodiments of the present application, the basic principle of the solution is briefly described here.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

The technical scheme provided by the embodiment of the application is described below with reference to the accompanying drawings.

With the increasing strictness of automotive emission regulations, aftertreatment systems with SCR become the mainstream technology for reducing emission pollution. The aftertreatment system with the SCR achieves the purpose of reducing NOx (nitrogen oxide) by injecting urea into the SCR tank, thereby reducing emission and meeting the requirements of emission regulations.

In view of the above, embodiments of the present application provide a dual-nozzle urea crystallization control method and an exhaust gas aftertreatment system, which can control the ccSCR urea injection amount and the SCR urea injection amount in a coordinated manner based on monitoring the overall NOx conversion efficiency, and control the urea crystallization amount to a lower level while optimizing the overall NOx conversion efficiency.

The preferred embodiments of the present application will be described below with reference to the accompanying drawings of the specification, it should be understood that the preferred embodiments described herein are merely for illustrating and explaining the present application, and are not intended to limit the present application, and that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Referring to fig. 1, an exhaust gas aftertreatment system 1000 provided by an embodiment of the present application includes a cccdoc system, a cccscr system, a DOC system, a DPF system, an SCR system, and an ASC system sequentially connected to an exhaust gas outlet of an engine through an exhaust pipe; a first nozzle is arranged between the ccSCR system and the ccDOC system; and a second nozzle is arranged between the SCR system and the DPF system.

The first nozzle and the second nozzle have independent urea injection calculation to respectively obtain the actual injection quantity Inj1 of the first nozzle and the actual injection quantity Inj2 of the second nozzle; the first nozzle and the second nozzle have respective urea crystal boundaries, and the first nozzle injection limit InjLim1 and the second nozzle injection limit InjLim2 are obtained, respectively.

In some other embodiments, the exhaust aftertreatment system 1000 further comprises:

an upstream NOx sensor and a downstream NOx sensor, the upstream NOx sensor and the downstream NOx sensor being respectively disposed at an inlet of the cccDOC system and an outlet of the ASC system; the system comprises an upstream temperature sensor and a downstream temperature sensor, wherein the upstream temperature sensor is arranged between a cccSCR system and a cccDOC system; the downstream temperature sensor is disposed between the DPF system and the SCR system.

The dual nozzle urea crystallization control method applicable to the exhaust gas aftertreatment system 1000 provided by the embodiments of the present application is further explained below. The double nozzles are respectively a first nozzle and a second nozzle which are arranged in front of the ccSCR system and the SCR system, and as shown in figure 2, the double nozzles comprise the following steps:

s201, monitoring the operation parameters of the tail gas treatment system.

The operating parameters include, but are not limited to, the following items of information: the control system comprises a first nozzle target injection amount, a first nozzle actual injection amount, a second nozzle target injection amount, a second nozzle actual injection amount and comprehensive NOx conversion efficiency corresponding to the ccSCR system and the SCR system.

Specifically, in the embodiment of the present application, the monitoring of the operation parameters of the exhaust gas treatment system may be periodically acquiring the operation parameters of the exhaust gas treatment system according to a fixed preset time interval. Illustratively, the preset time interval may be 100ms, for example. In this way, operating parameters at multiple points in time spaced 100ms apart may be obtained, and based on the operating parameters at two adjacent points in time, a rate of change of the operating parameters may be determined, e.g., in some embodiments, an overall NOx conversion efficiency may be determined.

The target injection amount of the nozzle may be determined according to the target conversion efficiency of the nozzle. In some embodiments, the nozzle target injection amount may be determined by an injection calibration MAP of the nozzle and a target conversion efficiency of the nozzle. The injection calibration MAP is a piece of specific data with conversion efficiency on the X-axis and injection quantity on the Y-axis. Therefore, as long as the target conversion efficiency exists, the injection calibration MAP of the nozzle can be checked to obtain the current target injection quantity of the nozzle. The injection calibration MAP may be determined based on bench testing.

In particular implementation, the overall NOx conversion efficiency corresponding to the ccSCR system and the SCR system as a whole can be determined by the NOx concentration at the inlet of the ccDOC system and at the outlet of the ASC system. In some embodiments, the NOx concentrations at the inlet of the cccdoc system and at the outlet of the ASC system may be obtained by an upstream NOx sensor and a downstream NOx sensor, respectively.

Assuming that the NOx concentrations at the inlet of the cccdoc system and at the outlet of the ASC system are NOx _1, NOx _2, respectively, the NOx conversion efficiency calculation Eff _ NOx can be calculated by the following equation:

in the dual nozzle urea crystallization control process, the calculation of the efficiency may preset enabling conditions including some or all of the following: the ccSCR temperature is within a preset first working temperature range, the SCR temperature is within a preset second working temperature range, the concentration of NOx _1 is within a preset concentration range, and the exhaust gas flow is within a preset flow range. When these conditions are satisfied simultaneously, the energy efficiency is calculated.

Taking the exhaust gas after-treatment system 1000 shown in fig. 1 as an example, the first nozzle is a first nozzle of the exhaust gas after-treatment system 1000, and the second nozzle is a second nozzle of the exhaust gas after-treatment system 1000, assuming that the operating parameters of the exhaust gas after-treatment system 1000 are monitored at time Tn +1, the method includes: the first nozzle target injection amount Dem1, the first nozzle actual injection amount Inj1, the second nozzle target injection amount Dem2, the second nozzle actual injection amount Inj2, and the NOx total conversion efficiency Eff _ NOx corresponding to the ccSCR system and the SCR system as a whole.

S202, when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold value and not lower than a second preset threshold value, whether a preset execution condition of the first coordination process is satisfied is judged.

Wherein the first coordination process is to increase the ejection volume of at least one of the first nozzle and the second nozzle in accordance with the first nozzle target ejection volume, the first nozzle actual ejection volume, the second nozzle target ejection volume, and the second nozzle actual ejection volume; the preset execution condition indicates that at least one of the first nozzle and the second nozzle is limited in ejection.

It is to be understood that the present application does not specifically limit the specific values of the first fluctuation threshold and the second fluctuation threshold.

Illustratively, assuming that the first preset threshold is Lim1, the second preset threshold is Lim2, and the value of Lim1 is greater than Lim2, for example, the current set value of Lim1 may be 98%, and the current set value of Lim2 may be 90%, when it is detected that the overall NOx conversion efficiency is 98% > Eff _ NOx ≧ 90%, it is determined whether the preset execution condition of the first coordination process is satisfied. The preset execution condition may be ((Dem 1 > Lim 1) or (Dem 2 > Lim 2)) indicating that the injection of at least one of the first nozzle and the second nozzle is restricted. The first coordination process is for increasing the ejection amount of at least one of the first nozzle and the second nozzle in accordance with the first nozzle target ejection amount Dem1, the first nozzle actual ejection amount Inj1, the second nozzle target ejection amount Dem2, and the second nozzle actual ejection amount Inj 2.

S203, if the preset execution condition of the first coordination process is satisfied, the first coordination process is performed on the ejection of the first nozzle and the second nozzle.

In one possible implementation, the operating parameters further include a first nozzle injection limit, a second nozzle injection limit; performing first coordination processing on the injection of the first nozzle and the second nozzle, specifically:

if the target injection quantity of the first nozzle exceeds the injection limit value of the first nozzle and the target injection quantity of the second nozzle does not exceed the injection limit value of the second nozzle, assigning the actual injection quantity of the first nozzle as the injection limit value of the first nozzle, and increasing the first efficiency closed-loop correction quantity to the actual injection quantity of the second nozzle; the first efficiency closed-loop correction is obtained by respectively carrying out difference operation on the target injection quantity of the first nozzle and the injection limit value of the first nozzle, and the injection limit value of the second nozzle and the actual injection quantity of the second nozzle, and selecting one with a small value from the two difference values if the two difference values are positive values; or the like, or, alternatively,

if the target injection quantity of the second nozzle exceeds the injection limit value of the second nozzle and the target injection quantity of the first nozzle does not exceed the injection limit value of the first nozzle, assigning the actual injection quantity of the second nozzle as the injection limit value of the second nozzle, and increasing the closed-loop correction quantity of the second efficiency to the actual injection quantity of the first nozzle; the second closed-loop efficiency correction is obtained by respectively carrying out difference operation on the target injection quantity of the second nozzle and the injection limit value of the first nozzle and the actual injection quantity of the first nozzle, and selecting one with a small value from the two difference values if the two difference values are positive values; or the like, or, alternatively,

For example, taking the example shown in fig. 1 as an example, if the ((Dem 1 > Lim 1) or (Dem 2 > Lim 2)) value is true, the preset execution condition of the first coordination process is satisfied, and the first coordination process is performed on the ejection of the first nozzle and the second nozzle, specifically: if the target injection quantity Dem1 of the first nozzle exceeds the injection limit InjLim1 of the first nozzle and the target injection quantity Dem2 of the second nozzle does not exceed the injection limit InjLim2 of the second nozzle, assigning the actual injection quantity Inj1 of the first nozzle as the injection limit InjLim1 of the first nozzle, and increasing the closed-loop correction quantity det _ Inj1 of the first efficiency to the actual injection quantity Inj2 of the second nozzle; the first efficiency closed-loop correction amount det _ Inj1 is obtained by respectively carrying out difference operation on the target injection amount Dem1 of the first nozzle and the injection limit InjLim1 of the first nozzle, and the injection limit InjLim2 of the second nozzle and the actual injection amount Inj2 of the second nozzle, and selecting one with a small value from the two difference values if the two difference values are positive values; for example, of the obtained parameters, dem1=100, injlim1=95, dem2=60, injlim2=96, inj1=80, inj2=60, the first efficiency closed-loop correction amount det _ Inj1 may be determined by the following method:

the target injection amount Dem1=100 of the first nozzle and the injection limit InjLim1=95 of the first nozzle, the injection limit InjLim2=96 of the second nozzle and the actual injection amount Inj2=60 of the second nozzle are respectively subjected to difference operation to obtain two differences: and 5 and 36, if the two obtained differences are both positive values, selecting one with a small value from the two differences 5 and 36 to obtain a first efficiency closed-loop correction amount det _ Inj1=5.

At this time, if the target injection amount Dem2 of the second nozzle exceeds the injection limit InjLim2 of the second nozzle and the target injection amount Dem1 of the first nozzle does not exceed the injection limit InjLim1 of the first nozzle, the actual injection amount Inj2 of the second nozzle is assigned as the injection limit InjLim2 of the second nozzle, and the closed-loop correction amount det _ Inj2 of the second efficiency is increased to the actual injection amount Inj1 of the first nozzle; the method for determining the second closed-loop correction amount det _ Inj2 is similar to the method for determining the first closed-loop correction amount det _ Inj1, the process for determining the second closed-loop correction amount det _ Inj2 specifically refers to the first closed-loop correction amount det _ Inj1, and the process for determining the second closed-loop correction amount det _ Inj2 is not repeated herein.

At this time, if the second nozzle target injection amount Dem2 exceeds the second nozzle injection limit InjLim2 and the first nozzle target injection amount Dem1 exceeds the first nozzle injection limit InjLim1, the first nozzle actual injection amount Inj1 is assigned as the first nozzle injection limit InjLim1 and the second nozzle actual injection amount InjLim2 is assigned as the second nozzle injection limit InjLim2, so that both the first nozzle and the second nozzle perform injection at their respective injection limits.

The dual nozzle urea crystallization control method shown in fig. 2 is implemented by monitoring the operating parameters of the tail gas treatment system; when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold and not lower than a second preset threshold, judging whether a preset execution condition of first coordination processing is satisfied; if the preset execution condition of the first coordination processing is met, performing the first coordination processing on the injection of the first nozzle and the second nozzle; the first coordination processing is used for increasing the injection quantity of at least one of the first nozzle and the second nozzle according to the target injection quantity of the first nozzle, the actual injection quantity of the first nozzle, the target injection quantity of the second nozzle and the actual injection quantity of the second nozzle which are included by the operation parameters; the preset execution condition indicates that at least one of the first nozzle and the second nozzle is limited in injection. The method is based on monitoring of the overall NOx conversion efficiency, the CCSCR urea injection amount and the SCR urea injection amount are controlled in a coordinated mode, and the urea crystallization amount is controlled to be a lower level while the overall NOx conversion efficiency is optimized.

In one possible implementation, the dual nozzle urea crystallization control method further includes:

and when the comprehensive NOx conversion efficiency is monitored to be lower than a second preset threshold value, the first nozzle and the second nozzle are enabled to respectively spray according to the target injection quantity of the first nozzle and the target injection quantity of the second nozzle.

For example, assuming that the first preset threshold is Lim1, the second preset threshold is Lim2, and the value of Lim1 is greater than Lim2, for example, the current set value of Lim1 may be 98% and the current set value of Lim2 may be 90%, when it is detected that the overall NOx conversion efficiency is lower than the second preset threshold Lim2, the first nozzle and the second nozzle are caused to inject according to the first nozzle target injection amount Dem1 and the second nozzle target injection amount Dem2, respectively. The method can release the limit values of the first nozzle and the second nozzle when the comprehensive NOx conversion efficiency is too low, so that the comprehensive NOx conversion efficiency is improved to the maximum extent.

In one possible implementation manner, the method further includes:

Illustratively, assuming that the first preset threshold is Lim1, the second preset threshold is Lim2, and the numerical value of Lim1 is greater than Lim2, for example, the current set value of Lim1 may be 98%, and the current set value of Lim2 may be 90%, when it is detected that the overall NOx conversion efficiency is not lower than the first preset threshold Lim1, the first nozzle and the second nozzle are caused to inject according to the first nozzle actual injection amount Inj1 and the second nozzle actual injection amount Inj2, respectively. The method can maintain the current injection states of the two nozzles when the comprehensive NOx conversion efficiency is very high, does not perform additional injection control, not only integrally controls the urea crystal quantity to be at a lower level, but also can efficiently ensure the high level of the comprehensive NOx conversion efficiency and ensure the accuracy and the high efficiency of the double-nozzle urea crystal control method.

In some embodiments, the dual-nozzle urea crystallization control can be further performed based on two factors, namely the comprehensive conversion efficiency of NOx and the change rate of the comprehensive conversion efficiency of NOx, the method can identify the state that the comprehensive conversion efficiency of NOx is at a general level and has a downward trend, and can perform finer control on urea crystallization, so that the occurrence of downward decrease of the comprehensive conversion efficiency of NOx can be reduced, and the overall conversion efficiency of NOx can be improved on the premise that the urea crystallization amount is controlled to be a lower level as a whole.

Similarly to the enabling conditions under which the calculation of the comprehensive NOx conversion efficiency can be set, the calculation of the comprehensive NOx conversion efficiency change rate during the two-nozzle urea crystallization control may also set in advance the enabling conditions for the calculation of the comprehensive NOx conversion efficiency change rate, the enabling conditions including some or all of: the ccSCR temperature is within a preset first working temperature range, the SCR temperature is within a preset second working temperature range, the concentration of NOx _1 is within a preset concentration range, and the exhaust gas flow is within a preset flow range. And when the conditions are simultaneously met, calculating the change rate of the comprehensive NOx conversion efficiency.

FIG. 3 is a flow chart illustrating another dual nozzle urea crystallization control method provided by the embodiment of the application. Referring to fig. 3, a process for dual nozzle urea crystallization control, comprising:

s301, monitoring the operation parameters of the tail gas treatment system.

Wherein the operating parameters include, but are not limited to, the following items of information: the control system comprises a first nozzle target injection amount, a first nozzle actual injection amount, a second nozzle target injection amount, a second nozzle actual injection amount, NOx comprehensive conversion efficiency corresponding to the entirety of the ccSCR system and the SCR system, a first nozzle injection limit value, a second nozzle injection limit value, a NOx comprehensive conversion efficiency change rate, a first temperature value of the ccSCR system and a second temperature value of the SCR system.

S302, when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold and not lower than a second preset threshold, whether the change rate of the comprehensive NOx conversion efficiency is smaller than a third preset threshold is judged. If yes, go to step S303; if not, go to step S304.

And S303, if the change rate of the comprehensive NOx conversion efficiency is smaller than a third preset threshold value, determining a first nozzle overrun injection limit value and a second nozzle overrun injection limit value corresponding to the first nozzle and the second nozzle respectively according to a preset overrun starting temperature range, a first temperature value of the CCSCR system and a second temperature value of the SCR system, and performing second coordination processing on the injection of the first nozzle and the second nozzle.

Wherein the third predetermined threshold is a negative number with a smaller absolute value.

Illustratively, the third preset threshold may be set to-0.01, and when the rate of change of the integrated NOx conversion efficiency is smaller than the third preset threshold, indicating that the integrated NOx conversion efficiency is at a general level and has a downward trend, determining a first nozzle over-limit injection limit Inj _ super _ Lim1 and a second nozzle over-limit injection limit Inj _ super _ Lim2 corresponding to the first nozzle and the second nozzle respectively according to a preset over-limit activation temperature range, a first temperature value T1 of the ccSCR system and a second temperature value T2 of the SCR system, and performing a second coordination process on the injection of the first nozzle and the second nozzle.

In an embodiment of the present application, a first nozzle overrun injection limit value and a second nozzle overrun injection limit value corresponding to a first nozzle and a second nozzle respectively are determined according to a preset overrun enabling temperature range, a first temperature value of a ccSCR system, and a second temperature value of the SCR system, specifically: and if the first temperature value of the ccSCR system and/or the second temperature value of the SCR system accord with a preset overrun starting temperature range, determining an overrun injection limit value of a first nozzle and/or an overrun injection limit value of a second nozzle respectively corresponding to the first nozzle and the second nozzle according to a first corresponding relation between the preset temperature value of the ccSCR system and the overrun injection limit value and/or a second corresponding relation between the temperature value of the SCR system and the overrun injection limit value.

In some embodiments, the first and second correspondences may be obtained by bench testing the ccSCR system and the SCR system.

In specific implementation, the second coordination treatment is performed on the injection of the first nozzle and the second nozzle, and at least includes the following three conditions:

in the first situation, if the first temperature value accords with the overrun starting temperature range and the second temperature value accords with the overrun starting temperature range, the second nozzles are controlled to spray according to the overrun spraying limit value of the second nozzles respectively, and the first nozzles are controlled to spray according to the overrun spraying limit value of the first nozzles; alternatively, the first and second electrodes may be,

in the second situation, if the first temperature value is in accordance with the overrun starting temperature range and the second temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the second nozzle, controlling the first nozzle to jet according to the overrun jet limit value of the first nozzle, and controlling the first nozzle to jet according to the jet return regulation value of the first nozzle and enabling the second nozzle to jet according to the continuous jet limit value of the second nozzle when the fact that the overspray amount of the first nozzle is detected to exceed the overrun jet limit value of the first nozzle is monitored; wherein the first nozzle spray return value is a first nozzle spray limit value; alternatively, the first and second electrodes may be,

in the third situation, if the second temperature value is in accordance with the overrun starting temperature range and the first temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the first nozzle, controlling the second nozzle to jet according to the overrun jet limit value of the second nozzle, and controlling the second nozzle to jet according to the jet return regulation value of the second nozzle and enabling the first nozzle to jet according to the continuous jet limit value of the first nozzle when the fact that the overspray amount of the second nozzle exceeds the overrun jet limit value of the second nozzle is monitored; wherein the second nozzle spray modulation value is a second nozzle spray limit value.

It will be appreciated that the first nozzle injection cutback value and the second nozzle injection cutback value may be other values determined based on the first nozzle injection limit and the second nozzle injection limit, respectively. In the second case, when it is detected that the first nozzle overspray exceeds the first nozzle overspray limit value, the first nozzle may be controlled to return to the last spraying state before entering the overspray, that is, the first nozzle is sprayed according to the spraying amount before the first nozzle overspray limit value. Similarly, in the third situation, when it is detected that the second nozzle over-spray amount exceeds the second nozzle over-spray amount limit value, the second nozzle is controlled to return to the last injection state before the second nozzle over-spray amount exceeds the second nozzle over-spray amount limit value to perform injection, that is, the injection is performed according to the injection amount of the second nozzle before the second nozzle over-spray amount limit value.

In specific implementation, the continuous injection limit value of the first nozzle can be obtained by multiplying a first continuous coefficient on the basis of the actual injection quantity of the first nozzle; the first continuation factor may be a quotient of the first nozzle over-injection limit and the first nozzle injection limit.

The second nozzle successive injection limit value may be obtained by multiplying a second successive coefficient on the basis of the actual injection quantity of the second nozzle; the second continuation factor may be a quotient of the second nozzle over-injection limit and the second nozzle injection limit.

It will be appreciated that the first succession coefficient and the second succession coefficient may also be one coefficient related to the quotient of the first nozzle over-injection limit and the first nozzle injection limit and the quotient of the second nozzle over-injection limit and the second nozzle injection limit, respectively. For example, the first continuation factor may be the quotient of the first nozzle over-injection limit and the first nozzle injection limit multiplied by an empirical factor.

For example, assuming that the first temperature value T1 of the ccSCR system is 200 ℃ and the second temperature value T2 of the SCR system is 185 ℃, the first temperature value T1 conforms to the overrun enabling temperature range, and the second temperature value T2 conforms to the overrun enabling temperature range, the second nozzles are controlled to respectively inject according to the second nozzle overrun injection limit Inj _ super _ Lim2, and the first nozzles are controlled to inject according to the first nozzle overrun injection limit Inj _ super _ Lim 1.

If the first temperature value T1=200 ℃ meets the overrun enabling temperature range and the second temperature value T2=185 ℃ does not meet the overrun enabling temperature range, and if InjLim1=95, injLim2=96, inj1=80, inj2=60, inj superu Lim1=114, the second nozzle continues to spray the limit value Inj _ sub _ Lim2=72, the first nozzle is controlled to spray according to the first nozzle overrun limit value Inj _ super _ Lim1=114, and when the first nozzle overrun is monitored to exceed the first nozzle overrun limit value, the first nozzle is controlled to spray according to the first nozzle spray limit value Inj Lim1=95, and the second nozzle is controlled to spray according to the second nozzle continued spray limit value Inj _ sub _ Lim2= 72.

If the second temperature value T2=185 ℃ meets the over-limit enabling temperature range and the first temperature value T1=200 ℃ does not meet the over-limit enabling temperature range, determining a continuous spraying limit value of the first nozzle, controlling the second nozzle to spray according to the over-limit spraying limit value of the second nozzle, and controlling the second nozzle to spray according to the spraying limit value InjLim2=96 of the second nozzle when the over-spraying amount of the second nozzle is monitored to exceed the over-limit spraying amount limit value of the second nozzle, and enabling the first nozzle to spray according to the continuous spraying limit value of the first nozzle.

Illustratively, the first temperature value T1 may be obtained from an upstream temperature sensor at the ccSCR system front end of the exhaust aftertreatment system 1000; the second temperature value T2 may be obtained from a downstream temperature sensor in the front end of the SCR system of the exhaust gas aftertreatment system 1000.

In a possible implementation manner, the second coordination processing is performed on the injection of the first nozzle and the second nozzle, and the fourth situation is further included, specifically, if the first temperature value and the second temperature value do not meet the overrun enabling temperature range, the first nozzle and the second nozzle are respectively caused to perform injection according to the actual injection amount of the first nozzle and the actual injection amount of the second nozzle.

S304, judging whether the preset execution condition of the first coordination processing is satisfied. If the preset execution condition of the first coordination process is satisfied, step S305 is executed.

S305, a first coordination process is performed on the ejection of the first nozzle and the second nozzle.

And if the preset execution condition of the first coordination processing is established, carrying out the first coordination processing on the injection of the first nozzle and the second nozzle.

The process of controlling the dual-nozzle urea crystallization in steps S301 to S305 may be executed by referring to the specific process of the foregoing embodiment, and the same parts are not described herein again.

The double-nozzle urea crystallization control method is simple and easy to implement, achieves the purpose of double-nozzle urea crystallization control through ECU program setting, optimizes the overall NOx conversion efficiency, and can control the urea crystallization amount to a lower level.

In one possible implementation, the dual nozzle urea crystallization control process further comprises the steps of:

step A1, determining a first accumulated over-spray amount and a second accumulated over-spray amount corresponding to a first nozzle and a second nozzle respectively.

In an embodiment of the present application, the monitoring of the operation parameters of the exhaust gas treatment system may be periodically acquiring the operation parameters of the exhaust gas treatment system according to a fixed preset time interval. Thus, the excessive ejection amounts of the first nozzle and the second nozzle in each period of time determined by the preset time interval may be acquired, and further, the first cumulative excessive ejection amount and the second cumulative excessive ejection amount corresponding to the first nozzle and the second nozzle, respectively, may be calculated.

And step A2, determining the first nozzle crystallization amount and the second nozzle crystallization amount according to the first accumulated overspray amount and the second accumulated overspray amount.

In particular, the quality of the newly generated crystals and the quality of the eliminated crystals of the first nozzle and the second nozzle in each time period determined by the preset time interval may be obtained. The quality of the newly generated crystals can be obtained by multiplying the overspray amount in the current time period by an environment correction coefficient and a crystal nucleus correction coefficient. Wherein the environment correction factor is related to temperature and flow rate, and the crystallization nucleus correction factor is related to crystallization amount in the previous time period. The quality of the eliminated crystals can be obtained by multiplying the crystal elimination speed in the current time period by the time length of the current time period. The crystallization elimination rate is a temperature-dependent coefficient. The ECU can determine an environment correction coefficient, a crystal nucleus correction coefficient and a crystal elimination speed through a prestored correction coefficient table.

And step A3, if the crystallization amount of the first nozzle or the crystallization amount of the second nozzle exceeds a preset crystallization limit value, performing crystallization regeneration heat treatment on the corresponding first nozzle or second nozzle.

In specific implementation, the ECU can respectively calculate the crystallization amount, and when the crystallization amount exceeds a preset limit value, the crystallization regeneration heat management is triggered to control the crystallization removal temperature.

Based on the same inventive concept, the embodiment of the application also provides a double-nozzle urea crystallization control device. The dual nozzles are respectively a first nozzle and a second nozzle installed before the ccSCR system and the SCR system, as shown in fig. 4, the apparatus includes:

a parameter monitoring unit 401, configured to monitor an operation parameter of the exhaust gas treatment system; the operation parameters comprise a first nozzle target injection quantity, a first nozzle actual injection quantity, a second nozzle target injection quantity, a second nozzle actual injection quantity and comprehensive NOx conversion efficiency corresponding to the ccSCR system and the SCR system;

a control strategy judgment unit 402, configured to, when it is monitored that the comprehensive NOx conversion efficiency is lower than a first preset threshold and is not lower than a second preset threshold, judge whether a preset execution condition of the first coordination process is satisfied; a first coordination process for increasing the ejection amount of at least one of the first nozzle and the second nozzle in accordance with the first-nozzle target ejection amount, the first-nozzle actual ejection amount, the second-nozzle target ejection amount, and the second-nozzle actual ejection amount; the preset execution condition represents that at least one of the first nozzle and the second nozzle is limited in spraying;

the control execution unit 403 performs the first coordination process on the ejection from the first nozzle and the ejection from the second nozzle when a preset execution condition of the first coordination process is satisfied.

In one possible implementation, the operating parameters further include a first nozzle injection limit, a second nozzle injection limit; the control execution unit 403 is specifically configured to:

In one possible implementation manner, as shown in fig. 5, the dual-nozzle urea crystallization control apparatus further includes a first control unit 501, and the first control unit 501 is configured to:

In one possible implementation manner, as shown in fig. 6, the dual-nozzle urea crystallization control apparatus further includes a second control unit 601, and the first control unit 601 is configured to: and when the comprehensive NOx conversion efficiency is not lower than a first preset threshold value, enabling the first nozzle and the second nozzle to respectively spray according to the actual injection quantity of the first nozzle and the actual injection quantity of the second nozzle.

In a possible implementation manner, the operation parameters further include a NOx comprehensive conversion efficiency change rate, a first temperature value of the ccSCR system, and a second temperature value of the SCR system; the control execution unit 403 is further configured to:

if the comprehensive NOx conversion efficiency change rate is smaller than a third preset threshold value, determining a first nozzle overrun injection limit value and a second nozzle overrun injection limit value corresponding to a first nozzle and a second nozzle respectively according to a preset overrun starting temperature range, a first temperature value of a ccSCR system and a second temperature value of the SCR system, and executing the following steps to perform second coordination processing on the injection of the first nozzle and the second nozzle: if the first temperature value accords with the overrun starting temperature range and the second temperature value accords with the overrun starting temperature range, the second nozzle is controlled to spray according to the overrun spraying limit value of the second nozzle respectively, and the first nozzle is controlled to spray according to the overrun spraying limit value of the first nozzle; alternatively, the first and second electrodes may be,

if the first temperature value is in accordance with the overrun starting temperature range and the second temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the second nozzle, controlling the first nozzle to jet according to the overrun jet limit value of the first nozzle, and controlling the first nozzle to jet according to the jet limit value of the first nozzle and enabling the second nozzle to jet according to the continuous jet limit value of the second nozzle when the fact that the overspray amount of the first nozzle is beyond the overrun jet limit value of the first nozzle is monitored; alternatively, the first and second liquid crystal display panels may be,

and if the second temperature value is in accordance with the overrun starting temperature range and the first temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the first nozzle, controlling the second nozzle to jet according to the overrun jet limit value of the second nozzle, and controlling the second nozzle to jet according to the jet limit value of the second nozzle when monitoring that the overspray amount of the second nozzle is in excess of the overspray amount limit value of the second nozzle, and enabling the first nozzle to jet according to the continuous jet limit value of the first nozzle.

In a possible implementation manner, the control execution unit 403 is further configured to: and if the first temperature value and the second temperature value do not accord with the overrun starting temperature range, the first nozzle and the second nozzle are respectively used for spraying according to the actual spraying amount of the first nozzle and the actual spraying amount of the second nozzle.

In a possible implementation manner, as shown in fig. 7, the method further includes a regeneration control unit 701, where the regeneration control unit 701 is configured to:

and if the crystallization amount of the first nozzle or the crystallization amount of the second nozzle exceeds a preset crystallization limit value, performing crystallization regeneration heat treatment on the corresponding first nozzle or second nozzle.

Based on the same technical concept, an embodiment of the present application further provides an electronic device, as shown in fig. 8, the electronic device is configured to implement the methods described in the above various method embodiments, for example, to implement the embodiment shown in fig. 2, and the electronic device may include a memory 801, a processor 802, an input unit 803, and a display panel 804.

A memory 801 for storing computer programs executed by the processor 802. The memory 801 may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function, and the like; the storage data area may store data created according to use of the electronic device, and the like. The processor 802 may be a Central Processing Unit (CPU), a digital processing unit, or the like. The input unit 803 may be used to acquire a user instruction input by a user. The display panel 804 is configured to display information input by a user or information provided to the user, and in this embodiment of the present application, the display panel 804 is mainly used to display a display interface of each application program in the terminal device and a control entity displayed in each display interface. Alternatively, the display panel 804 may be configured in the form of a Liquid Crystal Display (LCD) or an OLED (organic light-emitting diode).

The embodiment of the present application does not limit the specific connection medium among the memory 801, the processor 802, the input unit 803, and the display panel 804. In the embodiment of the present application, the memory 801, the processor 802, the input unit 803, and the display panel 804 are connected by the bus 805 in fig. 8, the bus 805 is represented by a thick line in fig. 8, and the connection manner between other components is merely illustrative and not limited. The bus 805 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown in FIG. 8, but that does not indicate only one bus or one type of bus.

The memory 801 may be a volatile memory (volatile memory), such as a random-access memory (RAM); the memory 801 may also be a non-volatile memory (non-volatile memory) such as, but not limited to, a read-only memory (rom), a flash memory (flash memory), a Hard Disk Drive (HDD) or a solid-state drive (SSD), or the memory 801 may be any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 801 may be a combination of the above memories.

The processor 802 is configured to call the computer program stored in the memory 801 to execute the method described in the above method embodiments, for example, to implement the embodiment shown in fig. 2.

Based on the same technical concept, the embodiment of the application also provides an exhaust gas post-treatment system, which comprises a cccdoc system, a cccscr system, a DOC system, a DPF system, an SCR system and an ASC system which are sequentially communicated with an engine exhaust outlet through an exhaust pipe, wherein the structure of the system is shown in fig. 1, a first nozzle is arranged between the cccscr system and the cccoc system; a second nozzle is arranged between the SCR system and the DPF system, and the exhaust gas after-treatment system is established according to the double-nozzle urea crystallization control method of the embodiment.

In one possible implementation manner, the method further includes:

the system comprises a first NOx sensor and a second NOx sensor, wherein the first NOx sensor and the second NOx sensor are respectively arranged at an inlet of the cccDOC system and an outlet of the ASC system; the first temperature sensor is arranged between the cccSCR system and the cccDOC system; the second temperature sensor is disposed between the DPF system and the SCR system.

The embodiment of the present application further provides a computer-readable storage medium, which stores computer-executable instructions required to be executed by the processor, and includes a program required to be executed by the processor.

In some possible embodiments, the aspects of a dual nozzle urea crystallization control method provided herein may also be realized in the form of a program product comprising program code for causing a terminal device to perform the steps of a dual nozzle urea crystallization control method according to various exemplary embodiments of the present application described above in this specification when the program product is run on the terminal device. For example, the electronic device may perform the embodiment as shown in fig. 2.

The program product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

A fan control program product for an embodiment of the present application may employ a portable compact disk read only memory (CD-ROM) and include program code, and may be run on a computing device. However, the program product of the present application is not limited thereto, and in this document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A readable signal medium may include a propagated data signal with readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A readable signal medium may be any readable medium that is not a readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including a physical programming language such as Java, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device over any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., over the internet using an internet service provider).

It should be noted that although several units or sub-units of the apparatus are mentioned in the above detailed description, such division is merely exemplary and not mandatory. Indeed, the features and functions of two or more units described above may be embodied in one unit, according to embodiments of the application. Conversely, the features and functions of one unit described above may be further divided into embodiments by a plurality of units.

Further, while the operations of the methods of the present application are depicted in the drawings in a particular order, this does not require or imply that these operations must be performed in this particular order, or that all of the illustrated operations must be performed, to achieve desirable results. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step execution, and/or one step broken down into multiple step executions.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable document processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable document processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable document processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable document processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A dual nozzle urea crystallization control method is characterized in that the dual nozzles are a first nozzle and a second nozzle which are respectively installed before a ccSCR system and an SCR system, and the method comprises the following steps:

monitoring an operating parameter of the tail gas treatment system; the operation parameters comprise a first nozzle target injection quantity, a first nozzle actual injection quantity, a second nozzle target injection quantity, a second nozzle actual injection quantity and comprehensive NOx conversion efficiency corresponding to the ccSCR system and the SCR system;

when the comprehensive NOx conversion efficiency is monitored to be lower than a first preset threshold value and not lower than a second preset threshold value, judging whether a preset execution condition of first coordination processing is met or not; the first coordination process is configured to increase an ejection amount of at least one of the first nozzle and the second nozzle in accordance with the first nozzle target ejection amount, the first nozzle actual ejection amount, the second nozzle target ejection amount, and the second nozzle actual ejection amount; the preset execution condition represents that at least one of the first nozzle and the second nozzle is limited in spraying;

2. The method of claim 1, wherein the operating parameters further comprise a first nozzle injection limit, a second nozzle injection limit; the performing the first coordination process on the ejection of the first nozzle and the second nozzle includes:

3. The method of claim 1, further comprising:

4. The method of claim 1, further comprising:

5. The method of claim 1, wherein the NOx integrated conversion efficiency is determined by first and second NOx concentration values measured by a first NOx sensor upstream of the ccSCR system and a second NOx sensor downstream of the SCR system, respectively.

6. The method of claim 2, wherein the operating parameters further comprise a rate of change of NOx integrated conversion efficiency, a first temperature value of the ccSCR system, a second temperature value of the SCR system; prior to the first coordinated processing of the ejection of the first nozzle and the second nozzle, the method further comprises:

if the change rate of the comprehensive NOx conversion efficiency is smaller than a third preset threshold value, determining a first nozzle over-limit injection limit value and a second nozzle over-limit injection limit value respectively corresponding to the first nozzle and the second nozzle according to a preset over-limit starting temperature range, the first temperature value and the second temperature value, and executing the following steps to perform second coordination processing on the injection of the first nozzle and the second nozzle:

if the first temperature value accords with the overrun starting temperature range and the second temperature value accords with the overrun starting temperature range, controlling the second nozzle to spray according to the overrun spraying limit value of the second nozzle, and controlling the first nozzle to spray according to the overrun spraying limit value of the first nozzle; alternatively, the first and second electrodes may be,

if the first temperature value is in accordance with the overrun starting temperature range and the second temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the second nozzle, controlling the first nozzle to jet according to the overrun jet limit value of the first nozzle, and controlling the first nozzle to jet according to the jet limit value of the first nozzle and enabling the second nozzle to jet according to the continuous jet limit value of the second nozzle when the fact that the overspray amount of the first nozzle exceeds the overspray amount limit value of the first nozzle is monitored; alternatively, the first and second electrodes may be,

if the second temperature value is in accordance with the overrun starting temperature range and the first temperature value is not in accordance with the overrun starting temperature range, determining a continuous jet limit value of the first nozzle, controlling the second nozzle to jet according to the overrun jet limit value of the second nozzle, and controlling the second nozzle to jet according to the jet limit value of the second nozzle and enabling the first nozzle to jet according to the continuous jet limit value of the first nozzle when the fact that the overspray amount of the second nozzle exceeds the overspray amount limit value of the second nozzle is monitored;

wherein the second-nozzle successive injection limit value is obtained by multiplying a second successive coefficient on the basis of the actual injection quantity of the second nozzle; the second succession coefficient is a coefficient related to a quotient of the second nozzle over-injection limit and the second nozzle injection limit; the first-nozzle successive injection limit value is obtained by multiplying a first successive coefficient on the basis of the actual injection quantity of the first nozzle; the first succession coefficient is a coefficient related to a quotient of the first nozzle over-injection limit and the first nozzle injection limit; the first nozzle over-spray amount is the over-spray amount of the first nozzle in the process that the first nozzle sprays according to the first nozzle over-limit spray limit value; and the second nozzle over-spray amount is the over-spray amount of the second nozzle in the process that the second nozzle sprays according to the second nozzle over-limit spray limit value.

7. The method of claim 6, wherein the second coordinated firing of the first and second nozzles further comprises:

and if the first temperature value and the second temperature value do not accord with the over-limit starting temperature range, enabling the first nozzle and the second nozzle to spray according to the actual spraying quantity of the first nozzle and the actual spraying quantity of the second nozzle respectively.

8. The method according to any one of claims 1-7, further comprising:

determining a first accumulated over-spray amount and a second accumulated over-spray amount corresponding to the first nozzle and the second nozzle respectively; the first accumulated overspray amount is determined based on the overspray amount of the first nozzle in each time period determined by the preset time interval when the operating parameters of the exhaust gas treatment system are periodically detected according to the preset time interval; the second accumulated overspray amount is determined based on the overspray amount of the second nozzle in each time period determined by the preset time interval when the operating parameters of the exhaust gas treatment system are periodically detected according to the preset time interval;

9. The method of any of claims 6-7, wherein the first temperature value is obtained from a first temperature sensor at a front end of the ccSCR system; the second temperature value is obtained from a second temperature sensor at the front end of the SCR system.

10. An exhaust gas after-treatment system comprises a cccDOC system, a cccSCR system, a DOC system, a DPF system, an SCR system and an ASC system which are sequentially communicated with an engine exhaust outlet through an exhaust pipe; the device is characterized in that a first nozzle is arranged between the ccSCR system and the ccDOC system; a second nozzle is provided between the SCR system and the DPF system, the exhaust gas after-treatment system being established according to the two-nozzle urea crystallization control method of any one of claims 1-7 or claim 8 or claim 9.

11. The exhaust aftertreatment system of claim 10, further comprising: