CN117307298A

CN117307298A - Diagnostic method and device of SCR (selective catalytic reduction) double-injection urea equipment and vehicle

Info

Publication number: CN117307298A
Application number: CN202311527216.9A
Authority: CN
Inventors: 张军; 杨金鹏; 张竞菲
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2023-11-15
Filing date: 2023-11-15
Publication date: 2023-12-29

Abstract

The application provides a diagnosis method, a diagnosis device and a diagnosis vehicle of SCR double-injection urea equipment, wherein the method comprises the following steps: closing the two nozzles under the condition that the change rate of the pressure value of the pumping equipment is smaller than a first preset value, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate; determining that the flow-through structure is malfunctioning if the first rate of change is not within a first predetermined range; under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, starting a target nozzle to spray urea, wherein the target nozzle is one of the two nozzles; acquiring the change rate of the pressure value in the urea injection process of the target nozzle, and obtaining a second change rate; and determining whether the target nozzle fails according to the second change rate, and determining that the target nozzle fails if the second change rate is not within a second preset range. The problem that is difficult to in time discover SCR dual injection urea equipment trouble has been solved to this application.

Description

Diagnostic method and device of SCR (selective catalytic reduction) double-injection urea equipment and vehicle

Technical Field

The application relates to the field of vehicle fault diagnosis, in particular to a diagnosis method and device of SCR double-injection urea equipment, a computer readable storage medium and a vehicle.

Background

The SCR (Selectively Catalytic Reduction, selective catalytic reduction) system can reduce NOx emission, and the double-SCR system can further improve NOx conversion efficiency, so that the engine can improve original NOx level and reduce oil consumption. The double SCR system needs SCR double-injection urea equipment, and the duty ratio of the nozzle 1 and the nozzle 2 is controlled to drive the nozzle to periodically inject urea into the tail pipe so as to achieve the aim of controlling emission. Currently, the SCR dual-injection urea device has a problem of clogging or leakage, thereby affecting the exhaust gas purification function of the SCR system.

Therefore, how to detect the working state of the SCR dual-injection urea device and discover the blockage or leakage problem of the SCR dual-injection urea device in time is a problem that needs to be solved in the prior art.

Disclosure of Invention

The main object of the present application is to provide a diagnostic method, a diagnostic device, a computer readable storage medium and a vehicle for an SCR dual-injection urea device, so as to at least solve the problem that in the prior art, it is difficult to find the fault of the SCR dual-injection urea device in time.

To achieve the above object, according to one aspect of the present application, there is provided a diagnostic method of an SCR dual injection urea plant comprising a urea storage plant, a flow-through structure comprising a pumping plant, a unidirectional return structure, a pumping line and a return line, a first end of the pumping plant communicating with the urea storage plant through the pumping line and the return line, respectively, the unidirectional return structure being located on the return line, the unidirectional return structure being open in case fluid in the return line flows from the pumping plant to the urea storage plant, a second end of the pumping plant communicating with both of the nozzles, the method comprising: closing two nozzles under the condition that the change rate of the pressure value of the pumping equipment is smaller than a first preset value, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate; a first determining step of determining whether or not the circulation structure is faulty according to the first rate of change, determining that the circulation structure is faulty if the first rate of change is not within a first predetermined range, and determining that the circulation structure is not faulty if the first rate of change is within the first predetermined range; a first opening step of opening a target nozzle to spray the urea under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, wherein the target nozzle is one of the two nozzles; the method comprises the steps of obtaining the change rate of the pressure value in the process of spraying urea by the target nozzle, and obtaining a second change rate; and a second determining step of determining whether the target nozzle is failed according to the second rate of change, and determining that the target nozzle is failed if the second rate of change is not within a second predetermined range.

Optionally, adjusting the pressure value of the pumping device, and obtaining the rate of change of the pressure value in the adjustment process, to obtain a first rate of change, including: acquiring the pressure values under the condition that two nozzles are closed, and obtaining a first pressure; reducing the duty cycle of the pumping device to a preset duty cycle to adjust the pressure value; determining that the adjustment is completed when the rate of change of the adjusted pressure value is smaller than a third preset value, and acquiring the corresponding pressure value when the adjustment is completed to obtain a second pressure; and determining the ratio of the difference value between the first pressure and the second pressure to the first interval duration as the first change rate according to the first pressure, the second pressure and the first interval duration, wherein the first interval duration is the acquisition interval duration between the first pressure and the second pressure.

Optionally, before opening the target nozzle to inject the urea, the method further comprises: a control step of controlling the duty cycle of the pumping device to be an initial duty cycle; the second opening step is to open the two nozzles and control the duty ratio of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity; and a third determining step of determining whether the rate of change of the pressure value is less than the second preset value.

Optionally, opening a target nozzle to spray the urea includes: keeping the target nozzle open and closing another nozzle other than the target nozzle with the duty ratio of the pumping device controlled unchanged, the obtaining step including: acquiring the pressure value under the condition that the target nozzle is opened to obtain a third pressure, and continuously acquiring a plurality of pressure values to obtain a plurality of fourth initial pressures; determining that the fourth initial pressure with the change rate smaller than the fourth preset value is a fourth pressure under the condition that the change rate of the fourth initial pressure is smaller than the fourth preset value; and determining the ratio of the difference value between the third pressure and the fourth pressure to the second interval duration as the second change rate according to the third pressure, the fourth pressure and the second interval duration, wherein the second interval duration is the acquisition interval duration between the third pressure and the fourth pressure.

Optionally, after the second determining step, the method further comprises: a third opening step of determining the other of the two nozzles as the target nozzle; and a loop step of circularly executing the control step, the second opening step, the third determination step, the first opening step, the acquisition step, and the second determination step once to determine whether the target nozzle is malfunctioning.

Optionally, one of the nozzles is used for injecting the urea into a preceding SCR device and the other nozzle is used for injecting the urea into a succeeding SCR device, the preceding SCR device and the succeeding SCR device are communicated and are arranged at intervals along a position far from the outlet of the turbine, and before the closing step, the method further comprises: acquiring the temperature of the front-stage SCR equipment, the temperature of the rear-stage SCR equipment, the accumulated urea injection quantity of the two nozzles, the exhaust gas discharge flow of the engine, the pressure value and the average conversion efficiency of the front-stage SCR equipment and the rear-stage SCR equipment; and controlling the duty ratio of the pumping equipment to be an initial duty ratio under the condition that the SCR double-injection urea equipment meets detection conditions, wherein the detection conditions comprise at least part of the following: the temperature of the pre-stage SCR equipment is in a preset temperature range, the temperature of the post-stage SCR equipment is in the preset temperature range, the accumulated urea injection quantity is larger than a fifth preset value, the exhaust gas discharge flow rate is in a third preset range, the pressure value is in a fourth preset range, and the average conversion efficiency is larger than a sixth preset value; opening two nozzles, and controlling the duty ratios of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity; determining whether the rate of change of the pressure value is less than the first preset value.

Optionally, in the event of a failure of the flow-through structure, the method further comprises: generating first fault information representing that the circulation structure breaks down, and sending the first fault information to a terminal, wherein in the case that the target nozzle is determined to break down, the method further comprises: disabling the target nozzle for urea injection; generating second fault information representing that the target nozzle breaks down, and sending the second fault information to the terminal.

According to another aspect of the present application, there is provided a diagnostic device of an SCR dual-injection urea apparatus, the SCR dual-injection urea apparatus comprising a urea storage apparatus, a circulation structure and two nozzles, the circulation structure comprising a pumping apparatus, a unidirectional return structure, a pumping line and a return line, a first end of the pumping apparatus being in communication with the urea storage apparatus via the pumping line and the return line, respectively, the unidirectional return structure being located on the return line, the unidirectional return structure being open with fluid in the return line flowing from the pumping apparatus to the urea storage apparatus, a second end of the pumping apparatus being in communication with two of the nozzles, the device comprising: the closing unit is used for closing the two nozzles under the condition that the change rate of the pressure value of the pumping equipment is smaller than a first preset value, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate; a first determining unit configured to determine, according to the first rate of change, whether the circulation structure is faulty, determine that the circulation structure is faulty if the first rate of change is not within a first predetermined range, and determine that the circulation structure is not faulty if the first rate of change is within the first predetermined range; the first opening unit is used for opening a target nozzle to spray the urea under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, and the target nozzle is one of the two nozzles; the first acquisition unit is used for acquiring the change rate of the pressure value in the process of injecting the urea by the target nozzle to obtain a second change rate; and a second determining unit configured to determine, according to the second rate of change, whether the target nozzle has failed, and determine that the target nozzle has failed if the second rate of change is not within a second predetermined range.

According to still another aspect of the present application, there is provided a computer readable storage medium, where the computer readable storage medium includes a stored program, and when the program runs, controls a device in which the computer readable storage medium is located to perform any one of the methods.

According to yet another aspect of the present application, there is provided a vehicle including: the SCR double-injection urea device comprises urea storage equipment, a circulating structure and two nozzles, wherein the circulating structure comprises pumping equipment, a unidirectional backflow structure, a pumping pipeline and a backflow pipeline, a first end of the pumping equipment is communicated with the urea storage equipment through the pumping pipeline and the backflow pipeline respectively, the unidirectional backflow structure is positioned on the backflow pipeline, and under the condition that fluid in the backflow pipeline flows from the pumping equipment to the urea storage equipment, the unidirectional backflow structure is opened, and a second end of the pumping equipment is communicated with the two nozzles; one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods.

By means of the technical scheme, the two nozzles are closed, the pressure change of the pumping equipment is detected to determine whether the circulating structure of the SCR dual-injection urea equipment breaks down, when the circulating structure does not break down, the nozzle is opened to detect whether the nozzle breaks down according to the pressure change of the pumping equipment, automatic detection of the SCR dual-injection urea equipment faults is achieved, the faults of the SCR dual-injection urea equipment can be found timely, and the circulating structure or the nozzle breaks down when the faults happen can be located, so that follow-up fault processing and maintenance are facilitated, and the problem that the faults of the SCR dual-injection urea equipment are difficult to find timely is effectively solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

FIG. 1 shows a block diagram of a hardware architecture of a mobile terminal that performs a diagnostic method of an SCR dual-injection urea apparatus, provided in an embodiment of the present application;

FIG. 2 illustrates a schematic structural diagram of an SCR dual-injection urea apparatus provided according to an embodiment of the present application;

FIG. 3 illustrates a flow diagram of a diagnostic method for an SCR dual-injection urea plant provided in accordance with an embodiment of the present application;

FIG. 4 illustrates a schematic diagram of pressure values over time of a diagnostic stage pumping device provided in accordance with an embodiment of the present application;

FIG. 5 illustrates a schematic structural diagram of a dual SCR system provided in accordance with an embodiment of the present application;

FIG. 6 illustrates a flow diagram of another diagnostic method for an SCR dual-injection urea plant provided in accordance with an embodiment of the present application;

FIG. 7 illustrates a schematic diagram of pressure values over time for another pumping device provided in accordance with an embodiment of the present application;

FIG. 8 shows a block diagram of a diagnostic device of an SCR dual-injection urea apparatus, provided according to an embodiment of the present application.

Wherein the above figures include the following reference numerals:

102. a processor; 104. a memory; 106. a transmission device; 108. an input-output device; 300. a urea storage device; 301. a nozzle; 302. a pumping device; 303. a unidirectional reflux structure; 304. a pumping line; 305. a return line; 306. a pump motor; 307. a pump pressure chamber; 308. a pressure sensor; 400. a first mixer; 401. a pre-stage SCR device; 402. DOC; 403. a DPF; 404. a second mixer; 405. a post-stage SCR device; 406. ASC; 407. a first temperature sensor; 408. a second temperature sensor; 409. a third temperature sensor; 410. a first NOx sensor; 411. a second NOx sensor.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

In order to make the present application solution better understood by those skilled in the art, the following description will be made in detail and with reference to the accompanying drawings in the embodiments of the present application, it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.

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

As described in the background art, in the prior art, there is a problem that it is difficult to find a fault of the SCR dual-injection urea device in time, and in order to solve the above technical problem, embodiments of the present application provide a diagnostic method, apparatus, computer readable storage medium and vehicle of the SCR dual-injection urea device.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The method embodiments provided in the embodiments of the present application may be performed in a mobile terminal, a computer terminal or similar computing device. Taking the operation on a mobile terminal as an example, fig. 1 is a hardware structural block diagram of the mobile terminal of a diagnosis method of an SCR dual-injection urea device according to an embodiment of the present invention. As shown in fig. 1, a mobile terminal may include one or more (only one is shown in fig. 1) processors 102 (the processor 102 may include, but is not limited to, a microprocessor MCU or a processing device such as a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 for communication functions and an input-output device 108. It will be appreciated by those skilled in the art that the structure shown in fig. 1 is merely illustrative and not limiting on the structure of the mobile terminal. For example, the mobile terminal may also include more or fewer components than shown in fig. 1, or have a different configuration than shown in fig. 1.

The memory 104 may be used to store a computer program, for example, a software program of application software and a module, such as a computer program corresponding to a diagnostic method of the SCR dual-injection urea apparatus in the embodiment of the present invention, and the processor 102 executes the computer program stored in the memory 104 to perform various functional applications and data processing, that is, to implement the method. Memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include memory remotely located relative to the processor 102, which may be connected to the mobile terminal via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or transmit data via a network. Specific examples of the network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, simply referred to as NIC) that can connect to other network devices through a base station to communicate with the internet. In one example, the transmission device 106 may be a Radio Frequency (RF) module, which is configured to communicate with the internet wirelessly.

In this embodiment, a diagnostic method for an SCR dual injection urea plant operating on a mobile terminal, a computer terminal or similar computing device is provided, it being noted that the steps illustrated in the flowchart of the figures may be performed in a computer system such as a set of computer executable instructions, and although a logical sequence is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in a different order than that illustrated herein.

Fig. 2 is a schematic structural diagram of an SCR dual-injection urea device according to an embodiment of the present application, as shown in fig. 2, where the SCR dual-injection urea device includes a urea storage device 300, a circulation structure and two nozzles 301, the circulation structure includes a pumping device 302, a unidirectional return structure 303, a pumping line 304 and a return line 305, a first end of the pumping device 302 communicates with the urea storage device 300 through the pumping line 304 and the return line 305, the unidirectional return structure 303 is located on the return line 305, the unidirectional return structure is opened in a case that fluid in the return line 305 flows from the pumping device 302 to the urea storage device 300, the unidirectional return structure is closed in a case that fluid in the return line 305 flows from the urea storage device 300 to the pumping device 302, and a second end of the pumping device 302 communicates with the two nozzles 301.

FIG. 3 is a flow chart of a diagnostic method of an SCR dual injection urea plant according to an embodiment of the present application. As shown in fig. 3, the method comprises the steps of:

step S201, closing two nozzles, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate when the change rate of the pressure value of the pumping equipment is smaller than a first preset value;

in particular, in case the rate of change of the pressure value of the pumping device is smaller than the first preset value, it is indicated that the pressure value in the pumping device is substantially stable. The specific numerical value of the first preset value can be flexibly set by a person skilled in the art according to actual needs, and the application is not particularly limited.

Step S202, a first determining step, wherein whether the circulation structure is faulty or not is determined according to the first change rate, the circulation structure is determined to be faulty if the first change rate is not within a first preset range, and the circulation structure is determined to be not faulty if the first change rate is within the first preset range;

specifically, the faults include a leakage fault and a blockage fault, that is, in a case where at least one of the pumping apparatus, the unidirectional return structure, the pumping pipe, and the return pipe has a leakage fault or a blockage fault, the first rate of change is not within the first predetermined range, and generally, as shown in fig. 4, in a case where the circulation structure has a leakage fault, the first rate of change corresponds to a maximum value that is greater than the first predetermined range, and in a case where the circulation structure has a blockage fault, the first rate of change corresponds to a minimum value that is less than the first predetermined range. The person skilled in the art may set the boundary value of the first predetermined range based on empirical values, or may determine, based on a number of experiments, a pressure threshold value in the pumping device satisfying the condition that the flow-through structure is not malfunctioning as the boundary value of the first predetermined range.

Step S203, a first opening step, in which a target nozzle is opened to spray the urea under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, wherein the target nozzle is one of the two nozzles;

in particular, when the rate of change of the pressure value is less than the second preset value, it is indicated that the pressure value in the pumping device is substantially stable at this time. The specific value of the second preset value can be flexibly set by a person skilled in the art according to actual needs, and the application is not particularly limited.

Step S204, obtaining the change rate of the pressure value in the process of spraying urea by the target nozzle, and obtaining a second change rate;

step S205, a second determining step, determining whether the target nozzle is faulty according to the second rate of change, and determining that the target nozzle is faulty if the second rate of change is not within a second predetermined range.

Specifically, the faults include a leakage fault and a blockage fault, that is, in a case where the target nozzle has a leakage fault or a blockage fault, the second rate of change is not within the second predetermined range, and in general, in a case where the target nozzle has a leakage fault, the second rate of change is greater than a maximum value of the second predetermined range, and in a case where the target nozzle has a blockage fault, the second rate of change is less than a minimum value of the second predetermined range. The person skilled in the art may set the boundary value of the second predetermined range based on empirical values, or may determine, based on a number of experiments, a pressure threshold value in the pumping device satisfying the condition that the nozzle is not malfunctioning as the boundary value of the second predetermined range.

By the embodiment, under the condition that the pressure value of the pumping equipment is stable, the two nozzles are controlled to be closed, the pressure value of the pumping equipment is adjusted, and a first change rate of the pressure value in the adjusting process is obtained; then determining whether a circulation structure including pumping equipment, a unidirectional return structure, a pumping pipeline and a return pipeline is faulty according to the magnitude of the first change rate; then, under the condition that the circulation structure is not failed and the pressure value is stable, starting a nozzle to spray urea; acquiring a second change rate of the pressure value of the opened nozzle in the urea injection process; finally, it is determined whether the open nozzle has failed based on the second rate of change. Compared with the prior art, the problem that the fault of the SCR double-injection urea equipment is difficult to find in time is solved, the fault of the SCR double-injection urea equipment can be found in time, the follow-up fault treatment and maintenance are facilitated, and the problem that the fault of the SCR double-injection urea equipment is difficult to find in time is effectively solved by opening one nozzle and detecting the nozzle according to the pressure change of the pumping equipment when the fault is not found by closing two nozzles and detecting the pressure change of the pumping equipment.

Furthermore, in case of a failure of the flow-through structure, the method further comprises: and (5) ending diagnosis. When the circulation structure is failed, whether the circulation structure is failed or the nozzle is failed can not be determined according to the detection result, so that the diagnosis is not continued, and the detection is continued after the failure of the circulation structure is eliminated.

It should be noted that, compare in the scheme of detecting the nozzle earlier and then detecting the circulation structure, confirm under the circumstances of trouble when detecting the nozzle, unable locking is the result that the nozzle self trouble caused, and the result that the circulation structure trouble caused, when follow-up again carries out the detection of circulation structure, if confirm the trouble, also unable determine whether the nozzle is trouble, and this application the scheme can confirm whether the circulation structure breaks down earlier, and this testing result is not influenced by whether the nozzle breaks down, and under the circumstances of discharge circulation structure trouble again, detect the nozzle again, can lock the fault position under the circumstances of confirming whether trouble.

In an alternative, adjusting the pressure value of the pumping device, and obtaining the rate of change of the pressure value during the adjustment process, to obtain a first rate of change, including:

Step S2011: acquiring the pressure values under the condition that two nozzles are closed, and obtaining a first pressure;

step S2012: reducing the duty cycle of the pumping device to a preset duty cycle to adjust the pressure value;

step S2013: determining that the adjustment is completed when the rate of change of the adjusted pressure value is smaller than a third preset value, and acquiring the corresponding pressure value when the adjustment is completed to obtain a second pressure;

in particular, in case the rate of change of the pressure value after adjustment is smaller than a point preset value, it is explained that the pressure value in the pumping device is substantially stable.

Step S2014: and determining the ratio of the difference value between the first pressure and the second pressure to the first interval duration as the first change rate according to the first pressure, the second pressure and the first interval duration, wherein the first interval duration is the acquisition interval duration between the first pressure and the second pressure.

In the embodiment, the pressure value is obtained under the condition that the two nozzles are closed to obtain the first pressure, the duty ratio of the pumping equipment is reduced to reduce the pressure in the pumping equipment, the current pressure value is obtained under the condition that the pressure value is stable to obtain the second pressure, and the change rate of the second pressure relative to the first pressure is compared to obtain the first change rate, so that the first change rate can be obtained easily.

In addition to the above manner, adjusting the pressure value of the pumping device, and obtaining the rate of change of the pressure value in the adjustment process, to obtain a first rate of change, may further include: reducing the duty cycle of the pumping device to a preset duty cycle to adjust the pressure value; acquiring the pressure value in the pumping equipment after the pressure value is regulated in real time to obtain a plurality of pressure values and acquisition moments corresponding to the pressure values; stopping acquiring the pressure value under the condition that the rate of change of the pressure value after adjustment is smaller than a third preset value; according to the obtained pressure values and the corresponding obtaining moments, calculating the corresponding pressure change rates of every two adjacent obtaining moments, and calculating the average value of the pressure change rates to obtain the first change rate. This allows the first rate of change to be obtained more accurately.

Optionally, before opening the target nozzle to inject the urea, the method further comprises: a control step of controlling the duty cycle of the pumping device to be an initial duty cycle; the second opening step is to open the two nozzles and control the duty ratio of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity; and a third determining step of determining whether the rate of change of the pressure value is less than the second preset value. In this embodiment, in the case that the circulation structure does not fail, the control step is performed. The second opening step and the third determining step are used for performing normal urea injection control on the SCR dual-injection urea equipment, so that the pressure value in the pumping equipment tends to be stable, and a proper environment is provided for a subsequent diagnosis stage.

Specifically, opening a target nozzle to spray the urea comprises: and under the condition that the duty ratio of the pumping equipment is controlled to be unchanged, keeping the target nozzle open, and closing the other nozzles except the target nozzle. And namely, the detection of the nozzle is carried out by keeping the duty ratio of the pumping equipment to be the corresponding duty ratio value under the condition that the change rate of the pressure value is smaller than a second preset value.

To further enable a simpler and easier obtaining of the second rate of change, in still further alternatives of the present application, the step of obtaining comprises: acquiring the pressure value under the condition that the target nozzle is opened to obtain a third pressure, and continuously acquiring a plurality of pressure values to obtain a plurality of fourth initial pressures; in the case that the change rate of the fourth initial pressure is smaller than a fourth preset value, indicating that the pressure value at the moment has tended to be stable, and determining that the fourth initial pressure with the change rate smaller than the fourth preset value is a fourth pressure at the moment; and determining the ratio of the difference value between the third pressure and the fourth pressure to the second interval duration as the second change rate according to the third pressure, the fourth pressure and the second interval duration, wherein the second interval duration is the acquisition interval duration between the third pressure and the fourth pressure.

Of course, other ways than those described may be used by those skilled in the art to obtain the second rate of change, and in some other embodiments, the obtaining step may further include: acquiring a pressure value in the pumping equipment in real time and acquiring time corresponding to the pressure value; stopping acquiring the pressure value under the condition that the acquired change rate of the pressure value is smaller than a fourth preset value; and calculating the corresponding pressure change rates of every two adjacent acquisition moments according to the acquired pressure values and the corresponding acquisition moments, and calculating the average value of the pressure change rates to obtain the second change rate. This allows the second rate of change to be obtained more accurately.

According to further exemplary aspects of the present application, after the second determining step, the method further comprises: a third opening step of determining the other of the two nozzles as the target nozzle; and a loop step of circularly executing the control step, the second opening step, the third determination step, the first opening step, the acquisition step, and the second determination step once to determine whether the target nozzle is malfunctioning. After checking whether one of the nozzles fails, through the embodiment, the normal operation of the SCR dual-injection urea equipment is recovered, and then the other nozzle is detected, so that the detection of whether the other nozzle fails is realized, the timely detection of the failure of the SCR dual-injection urea equipment is further realized, and the subsequent failure processing and maintenance work is further facilitated.

In yet another alternative embodiment, as shown in FIG. 5, one of the nozzles 301 is used to inject the urea into a forward stage SCR device 401 and the other nozzle 301 is used to inject the urea into a backward stage SCR device 405, the forward stage SCR device 401 and the backward stage SCR device 405 being in communication and spaced apart along a location remote from the turbine outlet. Before the closing step, the method further comprises:

step S206: acquiring the temperature of the front-stage SCR equipment, the temperature of the rear-stage SCR equipment, the accumulated urea injection quantity of the two nozzles, the exhaust gas discharge flow of the engine, the pressure value and the average conversion efficiency of the front-stage SCR equipment and the rear-stage SCR equipment;

specifically, the accumulated urea injection quantity is the accumulated injection quantity recorded by the ECU after each time the ECU is electrified; the average conversion efficiency is an average value of the conversion efficiency of the front-stage SCR equipment and the conversion efficiency of the rear-stage SCR equipment, and the conversion efficiency of the front-stage SCR equipment can be obtained by detecting the concentration of NOx treated by the front-stage SCR equipment through a first NOx sensor positioned behind the front-stage SCR equipment and dividing the concentration of NOx by the concentration of original NOx discharged by an engine; the conversion efficiency of the rear-stage SCR device can be obtained by detecting the concentration of NOx treated by the rear-stage SCR device through a second NOx sensor positioned behind the rear-stage SCR device and dividing the concentration of NOx by the concentration of NOx detected by the first NOx sensor.

Step S207: and controlling the duty ratio of the pumping equipment to be an initial duty ratio under the condition that the SCR double-injection urea equipment meets detection conditions, wherein the detection conditions comprise at least part of the following: the temperature of the pre-stage SCR equipment is in a preset temperature range, the temperature of the post-stage SCR equipment is in the preset temperature range, the accumulated urea injection quantity is larger than a fifth preset value, the exhaust gas discharge flow rate is in a third preset range, the pressure value is in a fourth preset range, and the average conversion efficiency is larger than a sixth preset value;

specifically, the detection conditions may include all the conditions, or may include only a part of the conditions, and those skilled in the art may flexibly set the detection conditions according to actual situations. In this application, the detection condition includes that the temperature of the preceding SCR device is within a predetermined temperature range, the temperature of the succeeding SCR device is within the predetermined temperature range, the accumulated urea injection amount is greater than a fifth preset value, the exhaust gas discharge flow rate is within a third preset range, the pressure value is within a fourth preset range, and the average conversion efficiency is greater than a sixth preset value, that is, the diagnostic phase is entered when all the conditions are satisfied.

Step S208: opening two nozzles, and controlling the duty ratios of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity;

step S209: determining whether the rate of change of the pressure value is less than the first preset value.

In the embodiment of the application, before fault diagnosis is performed, whether the vehicle meets at least part of the detection conditions is detected, and under the condition that the vehicle is determined to meet at least part of the detection conditions, the possibility that the SCR dual-injection urea equipment is in fault is indicated, and at the moment, normal urea injection control is performed on the SCR dual-injection urea equipment, so that the pressure value in the pumping equipment tends to be stable, and a proper environment is provided for the subsequent diagnosis stage.

In the actual application process, under the condition that the SCR double-injection urea equipment does not meet the detection condition, continuously determining whether the SCR double-injection urea equipment meets the detection condition or not until the SCR double-injection urea equipment meets the detection condition.

Specifically, in the event of a failure of the flow-through structure, the method further comprises: generating first fault information representing that the circulation structure breaks down, and sending the first fault information to a terminal, wherein in the case that the target nozzle is determined to break down, the method further comprises: disabling the target nozzle for urea injection; generating second fault information representing that the target nozzle breaks down, and sending the second fault information to the terminal. In the embodiment, the first fault information and the second fault information are generated and sent to the terminal, so that related personnel can timely know the fault condition of the SCR double-injection urea equipment through the terminal, and further, the related personnel can timely respond to the faults and process the faults conveniently.

Further, when the nozzle 1 of the two nozzles fails, the nozzle 1 is disabled, and the normal operation of the nozzle 2 is maintained; when the nozzle 2 fails, the nozzle 2 is disabled and the normal operation of the nozzle 1 is maintained.

In the event of a failure of the flow-through structure, the method further comprises: issuing a first alarm signal; in the event of a failure of the target nozzle, the method further comprises: a second alarm signal is issued.

In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the implementation process of the diagnostic method of the SCR dual injection urea plant of the present application will be described in detail below with reference to specific embodiments.

The embodiment relates to a diagnosis method of a specific SCR dual-injection urea device, wherein two nozzles of the SCR dual-injection urea device are respectively a nozzle 1 and a nozzle 2, as shown in fig. 6, and the method comprises the following steps:

step S1: determining whether a detection condition is satisfied, the detection condition including:

the temperature of the pre-stage SCR equipment is in a preset temperature range, the temperature of the post-stage SCR equipment is in the preset temperature range, the accumulated urea injection quantity is larger than a fifth preset value, the exhaust gas discharge flow rate is in a third preset range, the pressure value is in a fourth preset range, and the average conversion efficiency is larger than a sixth preset value;

Step S2: under the condition that the diagnosis condition is met, carrying out the diagnosis of the circulation structure, and when the diagnosis of the circulation structure fails, exiting the diagnosis and reporting the fault of the circulation structure, wherein the diagnosis process of the circulation structure is specifically as follows:

firstly, entering a normal control stage: the duty ratio of the pumping equipment is regulated, so that the pressure of the pumping equipment is stabilized at a set value, and the duty ratios of the nozzle 1 and the nozzle 2 are respectively controlled according to the required urea injection quantity;

and then entering a flow-through structure diagnosis stage: after the pressure is stable, the duty ratio of the pumping equipment is reduced, the reduced duty ratio is kept fixed, the nozzle 1 and the nozzle 2 are closed, and the change of the pressure of the pumping equipment is monitored until the pressure is stable; calculating the average change rate of the pressure change process, wherein as shown in fig. 7, if the pressure change is too fast or too slow, the circulating structure of the SCR double-injection urea equipment is considered to be faulty, and the subsequent detection is not performed;

step S3: when the circulation structure is free from faults, the jet capacity diagnosis of the nozzle 1 is carried out, and the nozzle 1 diagnosis process is specifically as follows:

firstly, entering a normal control stage: the normal control is restored, the duty ratio of the pumping equipment is regulated to enable the pressure of the pumping equipment to be stabilized at a set value, and the duty ratio of the nozzle 1 and the nozzle 2 is controlled respectively according to the required urea injection quantity;

Reenter nozzle 1 diagnostic phase: after the pressure is stabilized, the pump duty ratio with stable pressure is fixed, the nozzle 1 is opened for a period of time, the nozzle 2 is closed at the same time, and the pressure change of pumping equipment is monitored until the pressure is stabilized; calculating the average change rate of the pressure change process, and if the pressure change is too fast or too slow as shown in fig. 7, considering that the nozzle 1 has a blockage or leakage fault;

step S4: after the completion of the ejection capability diagnosis of the nozzle 1, the ejection capability diagnosis of the nozzle 2 is performed, and the nozzle 2 diagnosis process is specifically as follows:

reenter nozzle 2 diagnostic phase: after the pressure is stabilized, the pump duty ratio with stable pressure is fixed, the nozzle 2 is opened for a period of time, meanwhile, the nozzle 1 is closed, and the pressure change of pumping equipment is monitored until the pressure is stabilized; calculating the average change rate of the pressure change process, as shown in fig. 7, if the pressure change is too fast or too slow, then the nozzle 2 is considered to be faulty, blocked or leaked;

step S5: after the completion of the ejection capability diagnosis of the nozzle 2, a responsive failure and nozzle action are triggered according to the diagnosis result, specifically, when the failure 1 occurs, the nozzle 1 is disabled, the failure 2 occurs, the nozzle 2 is disabled, and when one of the failure 1 and the failure 2 occurs, the nozzle failure is reported.

According to the embodiment, the nozzle is closed, the pressure change of the circulating structure of the SCR dual-injection urea equipment is detected, the blockage and leakage faults of the pumping equipment and the pipeline are eliminated, then the nozzle 1 and the nozzle 2 are alternately opened and closed, the faults of the two nozzles and the pipeline are respectively detected, and the injection abnormality can be accurately and timely detected.

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

The embodiment of the application also provides a diagnostic device of the SCR double-injection urea equipment, and the diagnostic device of the SCR double-injection urea equipment can be used for executing the diagnostic method for the SCR double-injection urea equipment. The device is used for implementing the embodiments and the preferred embodiments, and is not described again. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

The following describes a diagnostic device of an SCR dual-injection urea apparatus provided in an embodiment of the present application.

FIG. 8 is a schematic diagram of a diagnostic device of an SCR dual-injection urea apparatus according to an embodiment of the present application. As shown in fig. 8, the apparatus includes:

A closing unit 10, configured to close two nozzles when the rate of change of the pressure value of the pumping device is less than a first preset value, adjust the pressure value of the pumping device, and obtain the rate of change of the pressure value in the adjustment process, so as to obtain a first rate of change;

A first determining unit 20 configured to determine, according to the first rate of change, whether the circulation structure is malfunctioning, determine that the circulation structure is malfunctioning if the first rate of change is not within a first predetermined range, and determine that the circulation structure is not malfunctioning if the first rate of change is within the first predetermined range;

A first opening unit 30 for opening a target nozzle to spray the urea, the target nozzle being one of the two nozzles, in a case where the circulation structure is not failed and the rate of change of the pressure value is less than a second preset value;

A first obtaining unit 40, configured to obtain a second rate of change by obtaining a rate of change of the pressure value during the urea injection process by the target nozzle;

and a second determining unit 50 configured to determine whether the target nozzle is malfunctioning according to the second rate of change, and determine that the target nozzle is malfunctioning if the second rate of change is not within a second predetermined range.

By the embodiment, under the condition that the pressure value of the pumping equipment is stable, the two nozzles are controlled to be closed by the closing unit, the pressure value of the pumping equipment is adjusted, and a first change rate of the pressure value in the adjusting process is obtained; determining, by a first determining unit, whether a circulation structure including pumping equipment, a unidirectional return structure, a pumping pipeline, and a return pipeline has failed according to the magnitude of the first rate of change; under the condition that the circulation structure is not failed and the pressure value is stable, a nozzle is opened to spray urea through a first opening unit; acquiring a second change rate of a pressure value of the opened nozzle in the urea injection process through a first acquisition unit; and determining whether the opened nozzle has failed or not according to the second change rate by a second determining unit. Compared with the prior art, the problem that the fault of the SCR double-injection urea equipment is difficult to find in time is solved, the fault of the SCR double-injection urea equipment can be found in time, the follow-up fault treatment and maintenance are facilitated, and the problem that the fault of the SCR double-injection urea equipment is difficult to find in time is effectively solved by opening one nozzle and detecting the nozzle according to the pressure change of the pumping equipment when the fault is not found by closing two nozzles and detecting the pressure change of the pumping equipment.

Furthermore, the device further comprises: and an ending unit for ending the diagnosis when the circulation structure fails. When the circulation structure is failed, whether the circulation structure is failed or the nozzle is failed can not be determined according to the detection result, so that the diagnosis is not continued, and the detection is continued after the failure of the circulation structure is eliminated.

In an alternative, the closing unit includes:

the first acquisition module is used for acquiring the pressure values under the condition that two nozzles are closed to obtain a first pressure;

A reducing module for reducing the duty cycle of the pumping device to a preset duty cycle to adjust the pressure value;

the first determining module is used for determining that the adjustment is completed when the rate of change of the adjusted pressure value is smaller than a third preset value, and obtaining the corresponding pressure value when the adjustment is completed to obtain a second pressure;

And the second determining module is used for determining that the ratio of the difference value between the first pressure and the second pressure to the first interval duration is the first change rate according to the first pressure, the second pressure and the first interval duration, and the first interval duration is the acquisition interval duration between the first pressure and the second pressure.

Optionally, the apparatus further comprises: a first control unit for controlling the duty cycle of the pumping device to be an initial duty cycle before starting the target nozzle to inject the urea; the second opening unit is used for opening the two nozzles in a second opening step, and controlling the duty ratios of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity; and a third determining unit configured to determine whether the rate of change of the pressure value is smaller than the second preset value in a third determining step. In this embodiment, in the case that the circulation structure does not fail, the control step is performed. The second opening step and the third determining step are used for performing normal urea injection control on the SCR dual-injection urea equipment, so that the pressure value in the pumping equipment tends to be stable, and a proper environment is provided for a subsequent diagnosis stage.

Specifically, the first opening unit includes: and the maintaining module is used for maintaining the opening of the target nozzle and closing the other nozzles except the target nozzle under the condition that the duty ratio of the pumping equipment is controlled to be unchanged. And namely, the detection of the nozzle is carried out by keeping the duty ratio of the pumping equipment to be the corresponding duty ratio value under the condition that the change rate of the pressure value is smaller than a second preset value.

In order to further achieve that the second rate of change is relatively simple and easy to obtain, in still other alternatives of the present application, the first obtaining unit includes: the second acquisition module is used for acquiring the pressure value under the condition that the target nozzle is opened to obtain a third pressure, and continuously acquiring a plurality of pressure values to obtain a plurality of fourth initial pressures; a third determining module, configured to, when the rate of change of the fourth initial pressure is less than a fourth preset value, indicate that the pressure value at the time has tended to be stable, and determine that the fourth initial pressure with the rate of change less than the fourth preset value is a fourth pressure; and the fourth determining unit is used for determining that the ratio of the difference value between the third pressure and the fourth pressure to the second interval duration is the second change rate according to the third pressure, the fourth pressure and the second interval duration, and the second interval duration is the acquisition interval duration between the third pressure and the fourth pressure.

Of course, other ways than the way described may be used by the person skilled in the art to obtain the second rate of change, and in some other embodiments, the first obtaining unit may further include: the third acquisition module is used for acquiring the pressure value in the pumping equipment and the acquisition time corresponding to the pressure value in real time; a stopping module, configured to stop acquiring the pressure value when the rate of change of the acquired pressure value is less than a fourth preset value; the calculating module is used for calculating the pressure change rate corresponding to each two adjacent acquisition moments according to the acquired pressure values and the corresponding acquisition moments, calculating the average value of the pressure change rates and obtaining the second change rate. This allows the second rate of change to be obtained more accurately.

According to other exemplary aspects of the present application, the apparatus further comprises: a third opening unit configured to perform a third opening step of determining the other of the two nozzles as the target nozzle after the second determining step; and a circulation unit configured to perform the control step, the second opening step, the third determination step, the first opening step, the acquisition step, and the second determination step once in a circulation manner to determine whether the target nozzle is malfunctioning. After checking whether one of the nozzles fails, through the embodiment, the normal operation of the SCR dual-injection urea equipment is recovered, and then the other nozzle is detected, so that the detection of whether the other nozzle fails is realized, the timely detection of the failure of the SCR dual-injection urea equipment is further realized, and the subsequent failure processing and maintenance work is further facilitated.

In yet another alternative embodiment, as shown in FIG. 5, one of the nozzles 301 is used to inject the urea into a forward stage SCR device 401 and the other nozzle 301 is used to inject the urea into a backward stage SCR device 405, the forward stage SCR device 401 and the backward stage SCR device 405 being in communication and spaced apart along a location remote from the turbine outlet. The apparatus further comprises:

the second acquisition unit is used for acquiring the temperature of the front-stage SCR equipment, the temperature of the rear-stage SCR equipment, the accumulated urea injection quantity of the two nozzles, the exhaust gas discharge flow of the engine, the pressure value and the average conversion efficiency of the front-stage SCR equipment and the rear-stage SCR equipment before the closing step;

A second control unit, configured to control a duty cycle of the pumping device to be an initial duty cycle if the SCR dual-injection urea device satisfies a detection condition, where the detection condition includes at least part of: the temperature of the pre-stage SCR equipment is in a preset temperature range, the temperature of the post-stage SCR equipment is in the preset temperature range, the accumulated urea injection quantity is larger than a fifth preset value, the exhaust gas discharge flow rate is in a third preset range, the pressure value is in a fourth preset range, and the average conversion efficiency is larger than a sixth preset value;

The fourth opening unit is used for opening the two nozzles and controlling the duty ratios of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity;

and a fifth determining unit configured to determine whether a rate of change of the pressure value is smaller than the first preset value.

Specifically, the device further comprises: the first generating unit is configured to generate first fault information indicating that the circulation structure is faulty, and send the first fault information to a terminal, where the first generating unit is configured to: the disabling unit is used for disabling the target nozzle to perform urea injection under the condition that the target nozzle is determined to be faulty; and the second generation unit is used for generating second fault information representing the fault of the target nozzle and sending the second fault information to the terminal. In the embodiment, the first fault information and the second fault information are generated and sent to the terminal, so that related personnel can timely know the fault condition of the SCR double-injection urea equipment through the terminal, and further, the related personnel can timely respond to the faults and process the faults conveniently.

The apparatus further comprises: the first sending unit is used for sending out a first alarm signal when the circulation structure fails; the apparatus further comprises: and the second sending unit is used for sending a second alarm signal when the target nozzle fails.

The diagnostic device of the SCR double-injection urea equipment comprises a processor and a memory, wherein the closing unit, the first determining unit, the first opening unit, the first obtaining unit, the second determining unit and the like are all stored in the memory as program units, and the processor executes the program units stored in the memory to realize corresponding functions. The modules are all located in the same processor; alternatively, the modules may be located in different processors in any combination.

The processor includes a kernel, and the kernel fetches the corresponding program unit from the memory. The inner core can be provided with one or more than one, and the problem that the faults of the SCR double-injection urea equipment are difficult to discover in time in the prior art is at least solved by adjusting the parameters of the inner core.

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

The embodiment of the invention provides a computer readable storage medium, which comprises a stored program, wherein the program is used for controlling equipment where the computer readable storage medium is located to execute a diagnosis method of the SCR double-injection urea equipment.

Specifically, the diagnostic method of the SCR dual-injection urea device comprises the following steps:

The embodiment of the invention provides a processor which is used for running a program, wherein the diagnostic method of the SCR double-injection urea equipment is executed when the program runs.

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

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

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

According to still another aspect of the present application, there is also provided a vehicle including:

the SCR dual injection urea plant as shown in fig. 2, comprising a urea storage plant 300, a flow-through structure and two nozzles 301, the flow-through structure comprising a pumping plant 302, a unidirectional return structure 303, a pumping line 304 and a return line 305, a first end of the pumping plant 302 being in communication with the urea storage plant 300 via the pumping line 304 and the return line 305, respectively, the unidirectional return structure 303 being located on the return line 305, the unidirectional return structure being open in case of fluid in the return line 305 flowing from the pumping plant 302 to the urea storage plant 300, the unidirectional return structure being closed in case of fluid in the return line 305 flowing from the urea storage plant 300 to the pumping plant 302, a second end of the pumping plant 302 being in communication with both the nozzles 301;

one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods.

The vehicle is characterized in that the two nozzles are closed by running the method, the pressure change of the pumping equipment is detected to determine whether the circulation structure of the SCR dual-injection urea equipment fails, and when the circulation structure of the SCR dual-injection urea equipment fails, the nozzle is opened to detect whether the nozzle fails according to the pressure change of the pumping equipment, so that the automatic detection of the failure of the SCR dual-injection urea equipment is realized, the failure of the SCR dual-injection urea equipment can be found in time, and the failure of the circulation structure or the failure of the nozzle can be located when the failure occurs, thereby being convenient for subsequent failure processing and maintenance and effectively solving the problem that the failure of the SCR dual-injection urea equipment is difficult to find in time.

In the alternative, as shown in fig. 2, the pumping device 302 comprises a pump motor 306 and a pump pressure chamber 307, a first end of the pump pressure chamber 307 communicates with the urea storage device 300 via the pumping line 304 and the return line 305, respectively, the pump motor 306 being located on the pumping line 304. The SCR dual-injection urea device further comprises a pressure sensor 308, the pump motor 306 pumps urea from the urea storage device 300 into a pump pressure chamber 307, the pressure value of the pumping device 302 is monitored through the pressure sensor 308, most of urea in the pump pressure chamber 307 drives the nozzle 301 to periodically inject urea into the tail pipe by controlling the duty ratio of the two nozzles 301, and a small part of urea in the pump pressure chamber 307 flows back to the urea storage device 300 through the unidirectional backflow structure 303. The unidirectional return structure 303 may be a unidirectional return valve or a unidirectional return hole.

In a practical application process, the vehicle further comprises a dual SCR system, and the dual SCR system is shown in fig. 5, and specifically includes a first mixer 400, a pre-stage SCR device 401, a DOC (Diesel Oxide Catalyst, an oxidation catalytic converter) 402, a DPF (Diesel Particulate Filter, a particulate matter trap) 403, a second mixer 404, a post-stage SCR device 405, and an ASC (Ammonia Scrubber Condensate, ammonia slip trap) 406, which are sequentially communicated in a direction away from the turbine, and further includes a first temperature sensor 407 before the pre-stage SCR device 401, a second temperature sensor 408 before the DPF403, a third temperature sensor 409 and a first NOx sensor 410 before the second mixer 404, and a second NOx sensor 411 after the ASC 406. Wherein one of said nozzles 301 is in communication with said first mixer 400 for injecting urea into the first mixer 400 and the other of said nozzles 301 is in communication with said second mixer 404 for injecting urea into the second mixer 404. The pre-stage SCR device 401 is configured to perform a first catalytic reduction on the exhaust gas to reduce nitrogen oxides in the exhaust gas; DOC402 is used to convert NO in the exhaust gas to NO ₂ While raising the exhaust gas temperature, assisting the normal operation of the DPF403 and the post-SCR device 405; the DPF403 is configured to trap the particulate matters in the exhaust gas, and when the amount of the trapped particulate matters reaches a certain level, passive regeneration or active regeneration is required, so as to restore the trapping capability of the DPF403 on the particulate matters; the post-stage SCR device 405 is configured to perform a second catalytic reduction on the exhaust gas to further reduce nitrogen oxides in the exhaust gas; ASC406 is used to oxidize excess ammonia. The first temperature sensor 407, the second temperature sensor 408, and the third temperature sensor 409 are configured to collect temperature values of mounting positions, whereThe first NOx sensor 410 and the second NOx sensor 411 are used to detect the NOx concentration.

In practical application, DOC is prepared by coating noble metal catalyst (such as Pt, etc.) on honeycomb ceramic carrier to reduce the chemical reaction activation energy of HC, CO and SOF in exhaust gas of engine, and make them and oxygen in exhaust gas undergo oxidation reaction at low temperature and finally convert them into CO ₂ And H ₂ O. The DOC does not need a regeneration system and a control device, has the characteristics of simple structure and good reliability, and has been applied to modern small engines to a certain extent.

DPFs filter and trap particulates in engine exhaust primarily through diffusion, deposition, and impact mechanisms. The exhaust gas flows through the trap where particles are trapped in the filter element of the filter body, leaving cleaner exhaust gas to be discharged into the atmosphere. The wall-flow honeycomb ceramic filter is mainly used for engineering machinery and urban buses at present, and is characterized by simple operation and high filtering efficiency, but has the problems of regeneration of the filter and sensitivity to sulfur components in fuel oil.

The basic working principle of the DPF is as follows: as engine exhaust flows through the DOC, CO and HC are first almost entirely oxidized to CO at temperatures of 200-600deg.C ₂ And H ₂ O, with NO being converted to NO ₂ . After the exhaust gas enters the DPF from the DOC, the particles are trapped in the filter element of the filter body, and the cleaner exhaust gas is discharged into the atmosphere, so that the trapping efficiency of the DPF can reach more than 90%.

NO ₂ Has strong oxidizing ability to the trapped particles, and uses the generated NO ₂ Removal of particulates in a particulate trap and formation of CO as an oxidizing agent ₂ And NO ₂ And is reduced to NO, thereby achieving the purpose of removing particles.

The DOC internal reaction principle is as follows:

2NO+O ₂ →2NO ₂ ；2CO+O ₂ →2CO ₂ ；2CH+O ₂ →CO ₂ +H ₂ O。

the reaction principle in DPF is as follows:

C+2NO ₂ →CO ₂ +2NO，

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

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

Sulfur oxides form sulfates in copper-based SCR, reducing catalyst activity, plugging pores, and reducing the conversion efficiency of SCR to NOx, thus, after certain sulfur oxides are trapped in SCR, it is necessary to desulfurize it. There are 2 mechanisms of sulfur poisoning: generation (NH) ₄ )SO ₄ Etc., reduce the active site of SCR catalyst, block small holes, thereby reducingNOx conversion efficiency; SO (SO) ₂ And SO ₃ Competing with NOx for adsorption, reducing NOx adsorption.

The reaction principle of the catalytic reduction technology in the front-stage SCR equipment and the rear-stage SCR equipment is specifically as follows:

hydrolysis of urea to ammonia (urea injection system): (NH 2) ₂ CO+H ₂ O→2NH ₃ +CO ₂ ；

SCR aftertreatment reaction (SCR catalytic converter): NO+NO ₂ +2NH ₃ →2N ₂ +3H ₂ O；4NO+O ₂ +4NH ₃ →4N ₂ +6H ₂ O；2NO ₂ +O ₂ +4NH ₃ →3N ₂ +6H ₂ O。

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

It will be appreciated by those skilled in the art that the modules or steps of the invention described may be implemented in a general purpose computing device, they may be concentrated on a single computing device, or distributed across a network of computing devices, they may be implemented in program code that is executable by computing devices, so that they may be stored in a memory device for execution by computing devices, and in some cases, the steps shown or described may be performed in a different order than that shown or described, or they may be separately fabricated into individual integrated circuit modules, or multiple modules or steps of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

It will be appreciated by those skilled in the art that 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 the like) 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 flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations 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 data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data 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 data 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 data 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.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

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

Claims

1. A diagnostic method of an SCR dual-injection urea plant comprising a urea storage plant, a flow-through structure and two nozzles, the flow-through structure comprising a pumping plant, a unidirectional return structure, a pumping line and a return line, a first end of the pumping plant being in communication with the urea storage plant via the pumping line and the return line, respectively, the unidirectional return structure being located on the return line, the unidirectional return structure being open in case of fluid in the return line flowing from the pumping plant to the urea storage plant, a second end of the pumping plant being in communication with two of the nozzles, characterized in that the method comprises:

closing two nozzles under the condition that the change rate of the pressure value of the pumping equipment is smaller than a first preset value, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate;

A first determining step of determining whether or not the circulation structure is faulty according to the first rate of change, determining that the circulation structure is faulty if the first rate of change is not within a first predetermined range, and determining that the circulation structure is not faulty if the first rate of change is within the first predetermined range;

a first opening step of opening a target nozzle to spray the urea under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, wherein the target nozzle is one of the two nozzles;

the method comprises the steps of obtaining the change rate of the pressure value in the process of spraying urea by the target nozzle, and obtaining a second change rate;

and a second determining step of determining whether the target nozzle is failed according to the second rate of change, and determining that the target nozzle is failed if the second rate of change is not within a second predetermined range.

2. The method of claim 1, wherein adjusting the pressure value of the pumping device and obtaining a rate of change of the pressure value during the adjustment to obtain a first rate of change comprises:

Acquiring the pressure values under the condition that two nozzles are closed, and obtaining a first pressure;

reducing the duty cycle of the pumping device to a preset duty cycle to adjust the pressure value;

determining that the adjustment is completed when the rate of change of the adjusted pressure value is smaller than a third preset value, and acquiring the corresponding pressure value when the adjustment is completed to obtain a second pressure;

and determining the ratio of the difference value between the first pressure and the second pressure to the first interval duration as the first change rate according to the first pressure, the second pressure and the first interval duration, wherein the first interval duration is the acquisition interval duration between the first pressure and the second pressure.

3. The method of claim 1, wherein prior to opening a target nozzle to inject the urea, the method further comprises:

a control step of controlling the duty cycle of the pumping device to be an initial duty cycle;

the second opening step is to open the two nozzles and control the duty ratio of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity;

And a third determining step of determining whether the rate of change of the pressure value is less than the second preset value.

4. The method of claim 3, wherein the step of,

opening a target nozzle to spray the urea, including:

keeping the target nozzle open and closing another nozzle except the target nozzle under the condition that the duty ratio of the pumping device is controlled to be unchanged,

the acquisition step comprises the following steps:

acquiring the pressure value under the condition that the target nozzle is opened to obtain a third pressure, and continuously acquiring a plurality of pressure values to obtain a plurality of fourth initial pressures;

determining that the fourth initial pressure with the change rate smaller than the fourth preset value is a fourth pressure under the condition that the change rate of the fourth initial pressure is smaller than the fourth preset value;

and determining the ratio of the difference value between the third pressure and the fourth pressure to the second interval duration as the second change rate according to the third pressure, the fourth pressure and the second interval duration, wherein the second interval duration is the acquisition interval duration between the third pressure and the fourth pressure.

5. A method according to claim 3, wherein after the second determining step, the method further comprises:

A third opening step of determining the other of the two nozzles as the target nozzle;

and a loop step of circularly executing the control step, the second opening step, the third determination step, the first opening step, the acquisition step, and the second determination step once to determine whether the target nozzle is malfunctioning.

6. A method according to any one of claims 1 to 5, wherein one of said nozzles is for injecting said urea into a preceding SCR device and the other of said nozzles is for injecting said urea into a succeeding SCR device, said preceding SCR device and said succeeding SCR device being in communication and spaced apart along a location remote from the turbine outlet, said method further comprising, prior to the step of shutting down:

acquiring the temperature of the front-stage SCR equipment, the temperature of the rear-stage SCR equipment, the accumulated urea injection quantity of the two nozzles, the exhaust gas discharge flow of the engine, the pressure value and the average conversion efficiency of the front-stage SCR equipment and the rear-stage SCR equipment;

and controlling the duty ratio of the pumping equipment to be an initial duty ratio under the condition that the SCR double-injection urea equipment meets detection conditions, wherein the detection conditions comprise at least part of the following: the temperature of the pre-stage SCR equipment is in a preset temperature range, the temperature of the post-stage SCR equipment is in the preset temperature range, the accumulated urea injection quantity is larger than a fifth preset value, the exhaust gas discharge flow rate is in a third preset range, the pressure value is in a fourth preset range, and the average conversion efficiency is larger than a sixth preset value;

Opening two nozzles, and controlling the duty ratios of the two nozzles according to the required urea injection quantity so that the two nozzles inject the urea according to the required urea injection quantity;

determining whether the rate of change of the pressure value is less than the first preset value.

7. The method according to any one of claim 1 to 5, wherein,

in the event of a failure of the flow-through structure, the method further comprises: generating first fault information representing that the circulation structure breaks down, sending the first fault information to a terminal,

in the event that the target nozzle is determined to be malfunctioning, the method further comprises: disabling the target nozzle for urea injection; generating second fault information representing that the target nozzle breaks down, and sending the second fault information to the terminal.

8. A diagnostic device of an SCR dual-injection urea device, the SCR dual-injection urea device includes a urea storage device, a circulation structure and two nozzles, the circulation structure includes a pumping device, a unidirectional backflow structure, a pumping pipeline and a backflow pipeline, a first end of the pumping device is respectively communicated with the urea storage device through the pumping pipeline and the backflow pipeline, the unidirectional backflow structure is located on the backflow pipeline, the unidirectional backflow structure is opened under the condition that fluid in the backflow pipeline flows from the pumping device to the urea storage device, and a second end of the pumping device is communicated with two nozzles, the diagnostic device comprises:

The closing unit is used for closing the two nozzles under the condition that the change rate of the pressure value of the pumping equipment is smaller than a first preset value, adjusting the pressure value of the pumping equipment, and obtaining the change rate of the pressure value in the adjusting process to obtain a first change rate;

a first determining unit configured to determine, according to the first rate of change, whether the circulation structure is faulty, determine that the circulation structure is faulty if the first rate of change is not within a first predetermined range, and determine that the circulation structure is not faulty if the first rate of change is within the first predetermined range;

the first opening unit is used for opening a target nozzle to spray the urea under the condition that the circulation structure is not failed and the change rate of the pressure value is smaller than a second preset value, and the target nozzle is one of the two nozzles;

the first acquisition unit is used for acquiring the change rate of the pressure value in the process of injecting the urea by the target nozzle to obtain a second change rate;

and a second determining unit configured to determine, according to the second rate of change, whether the target nozzle has failed, and determine that the target nozzle has failed if the second rate of change is not within a second predetermined range.

9. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored program, wherein the program, when run, controls a device in which the computer readable storage medium is located to perform the method of any one of claims 1 to 7.

10. A vehicle, characterized by comprising:

the SCR double-injection urea device comprises urea storage equipment, a circulating structure and two nozzles, wherein the circulating structure comprises pumping equipment, a unidirectional backflow structure, a pumping pipeline and a backflow pipeline, a first end of the pumping equipment is communicated with the urea storage equipment through the pumping pipeline and the backflow pipeline respectively, the unidirectional backflow structure is positioned on the backflow pipeline, and under the condition that fluid in the backflow pipeline flows from the pumping equipment to the urea storage equipment, the unidirectional backflow structure is opened, and a second end of the pumping equipment is communicated with the two nozzles;

one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing the method of any of claims 1-7.