Method, device, system and medium for on-line detection of reducing agent injector injection characteristics

Abstract

Embodiments of the present application disclose a kind of reducing agent injector injection characteristic on-line detection method, device, equipment and storage medium.The reducing agent injector injection characteristic on-line detection method includes: when reducing agent injection system meets preset condition, freeze the control parameter of reducing agent injection system;Control injector opens and executes injection action at the same time, control pressure acquisition module to collect background pressure change curve, until the second background pressure characteristic corresponding to injector is in injection stable state;Injection background characteristic value is corrected and calculated;According to the result of correction calculation, it is judged whether the injection characteristic of injector fails.The reducing agent injector injection characteristic on-line detection method of the present embodiment is convenient to implement, and the injection characteristic of reducing agent is accurately detected.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of diesel engines, and particularly relates to an online diagnosis method for variation of injection characteristics of a reducing agent. BACKGROUND

[0002] Selective Catalyst Reduction (SCR) is a mainstream environmental protection technology for internal combustion engines (ICE) using fuel as a medium. The basic principle is to inject liquid reducing agent into the tailpipe of the ICE to cause an oxidation-reduction reaction with the NOx components in the exhaust gas, thereby controlling the emission of toxic NOx components into the atmosphere. The reducing agent supply and metering system used is the reducing agent injection system, which generally includes a reducing agent supply unit and a reducing agent injection unit, as well as necessary pipeline accessories. The supply unit provides a stable background pressure during system operation, and the metering unit uses an electromagnetic drive system to achieve time-controlled reducing agent metering and injection.

[0003] Since the reducing agent metering unit, i.e., the injector, is usually fixed to the exhaust pipe of the internal combustion engine, and the exhaust gas flowing in the exhaust pipe has characteristics such as high temperature, complex chemical composition, and the presence of particulate matter (Particulate Mass), over a long period of operation, the injector may change its injection characteristics, such as clogging of the injection holes, wear and corrosion of the injection holes, etc., which may cause deviations between the target reducing agent and the actual injected reducing agent, diesel emissions exceeding the standard, and other adverse consequences such as environmental pollution.

[0004] In view of the above, it is necessary to find a method to detect the metering and injection effect of the reducing agent metering unit throughout its service life, and to provide timely alarm and replacement for maintenance when the actual metering effect deviates from the expected value. Some of the currently disclosed methods use comprehensive emission results to determine whether the NOx toxic substances emitted from the exhaust pipe of the internal combustion engine exceed the standard, and provide an alarm when the NOx toxic substances exceed the standard. This method has obvious detection delay and cannot accurately locate the cause of the emission exceeding the standard. The NOx level emitted from the exhaust pipe is the result of a series of comprehensive measures, and the reason for the high NOx emission may be the deterioration of the SCR catalyst reducing agent or the unsuitable temperature conditions for the oxidation-reduction reaction. Some other methods use control characteristic parameters of the supply unit to detect the injection characteristics of the injector, such as changes in the speed or control parameters of the supply pump to represent the deviation of the injection characteristics of the injector. Similarly, this method is affected by factors such as wear and aging of the supply unit, and the detection reliability cannot meet the requirements. SUMMARY

[0005] The embodiment of the present application provides a kind of reducing agent injector injection characteristic on-line detection method, device, equipment and storage medium, realize accurate detection reducing agent injector injection characteristic.

[0006] According to an aspect of the present application, a reducing agent injector injection characteristic on-line detection method is provided, applied to a processing module of a reducing agent injection system, the reducing agent injection system also includes an injector and a pressure acquisition module, characterized in that the method comprises:

[0007] When the reducing agent injection system meets the preset condition, the control parameters of the reducing agent injection system are frozen so that the first background pressure characteristic corresponding to the injector is in a starting stable state;

[0008] While controlling the injector to start the injection action, the pressure acquisition module is controlled to acquire a background pressure change curve until the second background pressure characteristic corresponding to the injector is in an injection stable state, and the injector is controlled to stop the injection action.

[0009] The injection background characteristic value of the injector injection process is calculated, and the injection background characteristic value is corrected in combination with the preset system characteristic value; whether the injection characteristic of the injector fails is judged according to the correction result.

[0010] Optionally, the reducing agent injection system further includes a power supply module and a flowmeter, and the preset condition includes that the cumulative injection amount of the reducing agent injected by the injector recorded by the flowmeter exceeds a set threshold, and the system power supply voltage provided by the power supply module is within a set range.

[0011] Optionally, the background pressure change curve includes a background pressure drop curve and a background pressure stable curve connected in time sequence.

[0012] Optionally, the calculation of the injection background characteristic value of the injector injection process comprises:

[0013] The pressure difference ΔP of the background pressure from the starting stable state to the injection stable state is calculated, and the slope change array [k1, k2, k3...kn] of the background pressure from the starting stable state to the injection stable state is calculated. j ],

[0014] Wherein, ΔP=p[1]-p[n], n is the index of the last pressure value acquired;

[0015] k i =(p[i]-p[i+m]) / (m*sample rate), i is the i th change slope calculated, m is the number of samples spanned by the slope calculation window, where j represents the total number of obtained slope calculations, j=n-m+1.

[0016] Optionally, the preset system characteristic value at least includes a correction coefficient determined by a pipe length of the reduction injection system and a shape structure of the reduction agent supply pump.

[0017] Optionally, the correction calculation of the injection background characteristic value by the preset system characteristic value is performed by using the following formula:

[0018] △Pcor=△P*r

[0019] [k 1cor k 2cor …k jcor ]=[k1,k2,..k j ]*r;

[0020] k final =∑k jcor *f j

[0021] Wherein, △Pcor is the corrected pressure difference, △P is the uncorrected pressure difference, [k 1cor k 2cor …k jcor ] is the corrected slope change array, [k1,k2,..k j ] is the uncorrected slope change array, k final is the slope change comprehensive calculation characteristic value, k jcor is a single slope calculation element, f j is a weight coefficient of the single slope calculation element.

[0022] Optionally, the judging whether the injection characteristic of the injector is faulty according to the correction calculation result includes:

[0023] If the corrected pressure difference △Pcor is not in the first preset range or the slope change comprehensive calculation characteristic value k final is not in the second preset range, it is judged that the injection characteristic is in suspected fault;

[0024] If the corrected pressure difference △Pcor is not in the first preset range and the slope change comprehensive calculation characteristic value k final is not in the second preset range, it is judged that the injection characteristic is in abnormal fault;

[0025] If the corrected pressure difference △Pcor is in the first preset range and the slope change comprehensive calculation characteristic value k final is in the second preset range, it is judged that the injection characteristic is not in fault.

[0026] According to an aspect of the present application, there is provided a reduction agent injector injection characteristic on-line detection device, which comprises:

[0027] A pre-injection stabilization module is configured to freeze the control parameters of the reductant injection system when the reductant injection system meets preset conditions, so that the first background pressure characteristic of the injector is in a starting stabilization state;

[0028] An injection control module is configured to control the pressure acquisition module to acquire a background pressure change curve while the injector is controlled to start the injection action, and to control the injector to stop the injection action when the second background pressure characteristic of the injector is in an injection stabilization state.

[0029] A fault judgment module is configured to calculate an injection background characteristic value of the injector during the injection process, to correct the injection background characteristic value in combination with a preset system characteristic value, and to judge whether the injection characteristic of the injector is faulty according to the correction result.

[0030] According to another aspect of the present application, a reductant injection system is provided, which comprises:

[0031] at least one processor; and

[0032] a memory connected to the at least one processor in communication; wherein,

[0033] the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the reductant injector injection characteristic online detection method according to any one of the embodiments of the present application.

[0034] According to another aspect of the present application, a computer readable storage medium is provided, which stores computer instructions for enabling a processor to implement the reductant injector injection characteristic online detection method according to any one of the embodiments of the present application when executed by the processor.

[0035] The reductant injector injection characteristic online detection method according to the present embodiment is convenient to implement and can accurately detect the injection characteristic of the reductant. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0037] Figure 1 is a schematic diagram of a reductant injection system according to an embodiment of the present application;

[0038] Figure 2is a structural schematic view of a nozzle in a reducing agent injection system according to an embodiment of the present application;

[0039] Figure 3 is a schematic view of a background pressure change curve when a nozzle of a reducing agent injection system according to an embodiment of the present application is injecting;

[0040] Figure 4 is a flow chart of a method for on-line detection of injection characteristics of a reducing agent injector according to an embodiment of the present application;

[0041] Figure 5 is a schematic view of an on-line detection device for injection characteristics of a reducing agent injector according to an embodiment of the present application;

[0042] Figure 6 A structural schematic view of a reducing agent injection system 10 that can be used to implement embodiments of the present application is shown. DETAILED DESCRIPTION

[0043] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily mean a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0045] Embodiment one

[0046] Figure 1This is a schematic diagram of a reducing agent injection system according to Embodiment 1 of the present invention. The reducing agent injection system in this embodiment can be a diesel engine aftertreatment urea injection system, which includes a liquid tank 11, a suction pipe 12, a return pipe 13, a supply pump 14, a solution injection pipe 15, a nozzle (injector) 16, a pressure acquisition module (not shown), a power supply module, a flow meter, and a processing module. In this embodiment, the processing module can be an aftertreatment system controller (ACU), the urea solution serves as the liquid reducing agent in the reducing agent injection system, and the nozzle 16 can be an injector with a flow meter function, in which case the flow meter can be omitted. When the diesel engine is running, the aftertreatment system controller (ACU) calculates in real time the amount of liquid reducing agent to be injected into the exhaust pipe based on the diesel engine exhaust emission status, such as flow rate and temperature, and converts the liquid reducing agent injection amount into a drive signal for the nozzle 16 based on the supply pressure of the supply pump, driving the nozzle 16 to open. The nozzle 16 then injects the metered liquid reducing agent into the diesel engine exhaust pipe. The injected liquid reducing agent reacts with the toxic NOx in the diesel engine exhaust gas through an oxidation-reduction reaction, and is then released into the atmosphere as non-toxic nitrogen (N2), thereby achieving the purpose of purifying the air and protecting the environment.

[0047] Figure 2 This is a schematic diagram of the nozzle structure in the reducing agent injection system of Embodiment 1 of the present invention. Figure 2 As shown, in one embodiment, the nozzle 16 includes a liquid chamber 201, a solenoid valve 202, a switch 203, a spray chamber 204, and a nozzle orifice 205. The liquid chamber 201 and the spray chamber 204 are arranged adjacent to each other. The switch 203 is disposed between the liquid chamber 201 and the spray chamber 204. The solenoid valve 202 is disposed within the nozzle 16 and connected to the aftertreatment controller (ACU) via a wiring harness. Specifically, the solenoid valve 202 is disposed in an isolation groove outside the liquid chamber 201, isolating it from the liquid in the liquid chamber 201. Under the control of the solenoid valve 202, the switch 203 is used to selectively connect the liquid chamber 201 and the spray chamber 204.

[0048] In one embodiment, driven by the supply pump 14, the suction pipe 12 draws the reducing agent (urea solution) from the liquid tank 11. The urea solution circulates within the supply pump 14 and is then released back into the liquid tank 11 via the return pipe 13, forming a complete circulation loop. The urea solution in the supply pump 14 is transported to the liquid chamber 201 via a solution injection pipe 15. When the ACU control solenoid valve 202 is energized, the electromagnetic force causes the switch 203 to open, connecting the liquid chamber 201 and the injection chamber 204. The urea solution enters the injection chamber 204 from the liquid chamber 201 and is ejected from the nozzle 205, completing the injection action. The amount of urea solution injected by the nozzle 16 is determined by the duration of the control switch 203 opening after the solenoid valve 202 is activated. Simultaneously, the stable background pressure of the urea solution in the liquid chamber 201 ensures accurate measurement.

[0049] Under the driving force of the supply pump 14, the suction pipe 12 sucks the reducing agent (urea solution) from the liquid tank 11, and the urea solution is transported to one side of the liquid chamber 201 under the driving of the supply pump 14 through a solution injection pipe 15, so that the volume of the liquid chamber 201 is filled with the urea solution, and then the urea solution in the liquid chamber 201 enters another solution injection pipe 15 from the other side under the driving of the supply pump 14 through the liquid return pipe 13 to form a complete circulation loop. When the ACU controls the electromagnetic valve 202 to be energized, the electromagnetic force acts to open the switch 203, so that the liquid chamber 201 and the injection chamber 204 are connected through the switch 203. The urea solution enters the injection chamber 204 from the liquid chamber 201 and is sprayed from the injection hole 205 to complete the injection action. The amount of urea solution sprayed by the nozzle 16 is determined by the length of time for which the switch 203 is opened by energizing the electromagnetic valve 202 to control the switch 203, and at the same time, the background pressure of the urea solution in the liquid chamber 201 remains stable to ensure the accuracy of the metering.

[0050] Figure 3 The figure shows the background pressure change curve of the nozzle of the reducing agent injection system of the first embodiment of the present application. In this embodiment, the background pressure change curve of the nozzle 16 before and after the start of the injection action is divided into three stages, i.e. the first stage 31 before the start of the injection action, the second stage 32 after the start of the injection action, and the third stage 33 after the stop of the injection action. In the first stage 31, there is no injection action, and the pressure is maintained near the target pressure value with small fluctuations. The ACU obtains the actual pressure acquisition data of the pressure acquisition module, and controls the speed of the supply pump 14 through the feedback of the actual background pressure to control the fluctuations of the change curve of the first stage 31 within 2% of the target pressure. When the nozzle 16 starts to inject, the background pressure changes into the second stage 32 as shown in the figure, and the pressure rapidly decreases until the flow rate of the supply pump 14 increases to be equivalent to the injection flow rate of the injector, and the pressure is rebalanced. After the injection action is completed, the background pressure enters the third stage 33 as shown in the figure, and the background pressure naturally jumps up, and at the same time, the supply pump 14 enters the closed-loop regulation mode, and the background pressure is rebalanced near the target pressure as shown in the third stage 33. Figure 3 Figure 3 Figure 3

[0051] Figure 4 The figure is a flow chart of a reducing agent injector injection characteristic online detection method provided by the second embodiment of the present application. The method of the present embodiment can be applied to a reducing agent injector injection characteristic online detection device, and can be executed by the reducing agent injector injection characteristic online detection device. The device can be realized by software and / or hardware, and can be generally integrated in the reducing agent injection system of the first embodiment. The reducing agent injection system can include a terminal device, a server device or a single-chip microcomputer device, and the present embodiment does not limit the specific type of the reducing agent injection system. ​​​

[0052] Referring back to Figure 4 The method for on-line detection of the injection characteristics of the reductant injector of the present embodiment comprises the following steps.

[0053] S410, when the reductant injection system meets the preset condition, the control parameters of the reductant injection system are frozen so that the first background pressure characteristic corresponding to the injector is in the starting stable state.

[0054] In the present embodiment, the preset condition includes that the cumulative injection amount of the reductant injected by the injector recorded by the flow meter exceeds the set threshold, and the system power supply voltage provided by the power supply module is within the set range. In the present embodiment, the condition that the cumulative injection amount of the reductant (urea solution) injected by the injector (nozzle) recorded by the flow meter exceeds the set threshold can reduce the influence of the air remaining in the system pipeline on the subsequent detection accuracy; the condition that the system power supply voltage provided by the power supply module is within the set range can prevent the influence of the reductant flow fluctuation in the injection process caused by voltage fluctuation on the detection accuracy. In the present embodiment, the control parameters of the reductant injection system are frozen when the reductant injection system meets the preset condition; when the reductant injection system does not meet the preset condition, the reductant injection system is continuously monitored until the preset condition is met, and then the control parameters of the reductant injection system are frozen. In the present embodiment, the control parameters of the reductant injection system can keep the rotational speed of the supply pump 14 constant, so as to keep the reductant flow supplied by the supply pump 14 constant.

[0055] In the present embodiment, the preset starting condition for judging that the first background pressure characteristic corresponding to the injector is in the starting stable state is that the fluctuation amplitude of the first background pressure is less than 1% of the target pressure. Specifically, it can be judged within a continuous period of time, for example, within 5 seconds, whether the fluctuation amplitude of the first background pressure is less than 1%. In the present embodiment, since the control parameters of the reductant injection system are frozen, the rotational speed of the supply pump can be kept constant, the flow into the stable liquid cavity 201 is temporarily constant, and the flow through the return liquid pipe 13 of the supply pump 14 is also constant, so the background pressure stability is usually better at this time Figure 3 The first stage 31 is better, and the fluctuation of the background pressure in the first stage 31 is usually controlled within 2% of the target pressure.

[0056] In the present embodiment, if the stability meets the set requirement, for example, the fluctuation amplitude of the first background pressure is less than 1% of the target pressure, the subsequent step S420 is executed, otherwise the waiting continues until the stability still cannot meet the set requirement after exceeding the continuous period of time, which indicates that the system cannot continue to work, and the whole process is directly ended.

[0057] S420, control the pressure acquisition module to collect the background pressure change curve while the injector is controlled to start the injection action, until the second background pressure feature corresponding to the injector is in the injection stable state, and the injector is controlled to stop the injection action.

[0058] In this embodiment, the pressure acquisition module collects the background pressure change curve in Figure 3 The second stage 32 shown in the figure is performed, and the background pressure change curve of the second stage 32 includes a background pressure drop curve and a background pressure stable curve connected in time sequence. The electromagnetic valve 202 in the nozzle 16 is energized to enter the background pressure drop curve, and the liquid reducing agent background pressure behaves as shown in the drop part of the second stage 32 in Figure 3 The background pressure values are continuously collected at a rate of 10 ms and put into an array p[n], and the size of the array is usually determined according to the duration of the second stage 32. After the injection background pressure is stable, the background pressure stable curve is entered, as shown in the flat part of the second stage 32 in Figure 3 The pressure acquisition is ended at this time.

[0059] In an alternative embodiment, the injection stable condition for judging that the second background pressure feature corresponding to the injector is in the injection stable state can be, for example, the injection stable condition corresponding to the flat part of the second stage 32 in Figure 3 For example, the injection background pressure fluctuation amplitude is less than 1% of the stable value and the duration exceeds a preset time threshold value 3s. If the injection stable condition is met, step S430 is performed, otherwise the waiting continues until the injection stable condition is met or the time is exceeded to perform step S430.

[0060] The nozzle 16 is controlled to stop the injection action, and the closed-loop control function of the supply pump 14 can be restored. At this time, the nozzle 16 background injection pressure rises and returns to the vicinity of the target value, as shown in the curve corresponding to the third stage 33 in Figure 3 .

[0061] S430, calculate the injection background characteristic value of the injector injection process, and combine the preset system characteristic value to correct the injection background characteristic value; according to the correction result, judge whether the injection characteristic of the injector fails.

[0062] In this embodiment, the calculation of the injection background characteristic value of the injector injection process includes:

[0063] The pressure difference ΔP between the background pressure from the starting stable state to the injection stable state is calculated, and the slope change array [k1, k2, k3...k j ] between the background pressure from the starting stable state to the injection stable state is calculated.

[0064] Wherein, ΔP=p[1]-p[n], n is the last pressure value index collected.

[0065] k i = (p[i]-p[i+m]) / (m*sampling rate), where i is the i-th slope of change calculated, m is the number of samples spanned by the slope calculation window, and j represents the total number of slope calculations obtained, j = n-m+1.

[0066] For example, if the sampling rate is 10ms and the slope calculation window spans 100ms, then m = 10.

[0067] In one embodiment, the preset system characteristic values ​​include at least a correction coefficient, which is determined by the pipe length of the reducing injection system (the total length of the suction pipe 12, return pipe 13, and solution injection pipe 15) and the shape and structure of the internal liquid passage of the reducing agent supply pump 14. The pressure change difference and background pressure change slope obtained from the above calculations are only basic values ​​and need to be corrected according to the correction coefficient, such as the length of the injection pipe 15 and the structural characteristic parameters of the supply pump 14, such as the size of the return orifice. The calculation of correcting the injection background characteristic values ​​in combination with the preset system characteristic values ​​is performed using the following formula:

[0068] △Pcor=△P*r

[0069] [k 1cor k 2cor …k jcor ]=[k1,k2,..k j ]*r;

[0070] k final =∑k jcor *f j

[0071] Where ΔPcor is the corrected pressure difference, ΔP is the pressure difference before correction, [k 1cor k 2cor …k jcor [k1, k2, ..., k] represents the corrected slope change array. j [k] represents the slope change array before correction. final To calculate the eigenvalues ​​for the slope variation, k jcor For a single slope, calculate the element, f j Calculate the weight coefficient of an element for a single slope.

[0072] In one embodiment, f j It can be a sequence [1 / 2, 1 / 3, 1 / 4, ..., 1 / (j+1)], and the above formula k final =∑k jcor *f j The specific expression can be: k final = (1 / 2)*k 1cor +(1 / 3)*k2cor +....(1 / (j+1))*k jcor .

[0073] In this embodiment, determining whether the injector's injection characteristics have malfunctioned based on the corrected calculation results includes:

[0074] If the corrected pressure difference ΔPcor is not within the first preset range [ΔP] min ,△P max Or, the characteristic value k is calculated by comprehensively considering the slope change. final Not within the second preset range [K] min ,K max If the jetting characteristics are suspected to be malfunctioning, then it is determined that a fault has occurred.

[0075] If the corrected pressure difference ΔPcor is not within the first preset range [ΔP] min ,△P max Furthermore, the slope change is used to comprehensively calculate the characteristic value k. final Not within the second preset range [K] min ,K max If the jetting characteristics are abnormal, then it is determined that an abnormality has occurred.

[0076] If the corrected pressure difference ΔPcor is within the first preset range [ΔP] min ,△P max Furthermore, the slope change is used to comprehensively calculate the characteristic value k. final Within the second preset range [K] min ,K max If the result is positive, then the injection characteristics are determined to be normal.

[0077] The online detection method for reducing agent injector spray characteristics of this invention solves the problem of inaccurate detection of reducing agent spray volume in the prior art. It has high detection reliability, short delay, requires no additional cost and is easy to implement, and achieves accurate detection of reducing agent spray characteristics, thus ensuring the reliability of system operation.

[0078] Example 3

[0079] Figure 5 This is a schematic diagram of an online detection device for the spray characteristics of a reducing agent injector provided in Embodiment 3 of the present invention, as shown below. Figure 5 As shown, the device 500 includes: a pre-spray stabilization module 510, a spray control module 520, and a fault judgment module 530.

[0080] The pre-injection stabilization module 510 is used to freeze the control parameters of the reducing agent injection system when the reducing agent injection system meets the preset conditions, so that the first background pressure characteristic corresponding to the injector is in a stable state.

[0081] The injection control module 520 is used to control the injector to start and perform the injection action, while controlling the pressure acquisition module to collect the background pressure change curve, until the second background pressure characteristic corresponding to the injector is in a stable injection state, and then controlling the injector to stop the injection action.

[0082] The fault diagnosis module 530 is used to calculate the injection background characteristic value of the injector injection process, and to correct the injection background characteristic value by combining it with the preset system characteristic value; and to determine whether the injection characteristics of the injector have failed based on the correction calculation result.

[0083] Optionally, the pre-spray stabilization module 510 further includes an inlet condition judgment module for determining whether the reducing agent spraying system meets preset conditions. When the reducing agent spraying system meets the preset conditions, the control parameters of the reducing agent spraying system are frozen; when the reducing agent spraying system does not meet the preset conditions, the reducing agent spraying system is continuously monitored until the preset conditions are met before the control parameters of the reducing agent spraying system are frozen. In this embodiment, meeting the preset conditions includes the cumulative amount of reducing agent sprayed by the injector recorded by the flow meter exceeding a set threshold, and the system power supply voltage provided by the power supply module being within a set range. In this embodiment, the condition that the cumulative amount of reducing agent (urea solution) sprayed by the injector (nozzle) recorded by the flow meter exceeds the set threshold can reduce the impact of air in the system pipeline on the subsequent detection accuracy; the condition that the system power supply voltage provided by the power supply module is within a set range can prevent voltage fluctuations from causing fluctuations in the reducing agent flow rate during spraying and affecting the detection accuracy.

[0084] Optionally, the pre-injection stabilization module 510 also includes a parameter freezing module for freezing the control parameters of the reducing agent injection system so that the first background pressure characteristic corresponding to the injector is in an initial stabilizing state.

[0085] In this embodiment, the condition for determining that the first background pressure characteristic corresponding to the injector is in a state of initial stabilization is: the fluctuation amplitude of the first background pressure is less than 1% of the target pressure. Specifically, this can be determined over a continuous period of time, such as 5 seconds, whether the fluctuation amplitude of the first background pressure is less than 1%. In this embodiment, since the control parameters of the reducing agent injection system are frozen, the speed of the supply pump can be kept constant, the flow rate entering the stable liquid chamber 201 is temporarily constant, and the flow rate through the return pipe 13 of the supply pump 14 is also constant. Therefore, the background pressure stability is usually relatively high at this time. Figure 3 The first stage 31 is better, and the background pressure fluctuation of the first stage 31 is usually controlled within 2% of the target pressure.

[0086] Optionally, the injection control module 520 also includes an injection start module, which controls the injector to start performing the injection action while controlling the pressure acquisition module to acquire the background pressure change curve until the second background pressure characteristic corresponding to the injector is in a stable injection state.

[0087] In this embodiment, the pressure acquisition module acquires the background pressure change curve. Figure 3 The second stage 32 is shown, and the background pressure change curve of the second stage 32 includes a background pressure decrease curve and a background pressure stabilization curve connected sequentially in time. Energizing the solenoid valve 202 inside nozzle 16 initiates the background pressure decrease curve, and the background pressure of the liquid reducing agent exhibits the following behavior: Figure 3 The second stage 32 is shown as the decreasing portion. Background pressure values ​​are continuously acquired at a rate of 10 ms and stored in the array p[n]. The array size is typically determined by the duration of the second stage 32. After the injection background pressure stabilizes, the background pressure stabilization curve is entered, as shown... Figure 3 As shown in the smooth portion of the second stage 32, pressure acquisition ends at this point. In an alternative embodiment, the injection stability condition for determining that the second background pressure feature corresponding to the injector is in a injection stability state can be as follows: Figure 3 The smooth portion of the second stage 32 corresponds to the injection stabilization conditions, such as the injection background pressure fluctuation amplitude being less than 1% of the stable value and the duration exceeding the preset time threshold of 3s.

[0088] Optionally, the injection control module 520 also includes an injection stop module for controlling the injector to stop its operation.

[0089] By stopping the nozzle 16 from spraying, the closed-loop control function of the supply pump 14 can be restored. At this time, the background spray pressure of the nozzle 16 rises and returns to near the target value. Figure 3 The curve corresponding to the third stage 33 shown.

[0090] Optionally, the fault diagnosis module 530 also includes a feature value calculation module for calculating the injection background characteristic values ​​of the injector injection process.

[0091] In this embodiment, the calculation of the injection background characteristic values ​​of the injector injection process includes:

[0092] Calculate the pressure difference ΔP between the initial steady-state background pressure and the injection steady-state, and calculate the slope variation array [k1,k2,k3...k] between the initial steady-state background pressure and the injection steady-state. j ].

[0093] Where △P=p[1]-p[n], n is the index of the last pressure value collected.

[0094] k i= (p[i]-p[i+m]) / (m*sampling rate), where i is the i-th slope of change calculated, m is the number of samples spanned by the slope calculation window, and j represents the total number of slope calculations obtained, j = n-m+1.

[0095] For example, if the sampling rate is 10ms and the slope calculation window spans 100ms, then m = 10.

[0096] Optionally, the fault diagnosis module 530 also includes a feature value correction module, which is used to perform correction calculations on the spray background feature value in combination with preset system feature values.

[0097] In one embodiment, the preset system characteristic values ​​include at least a correction coefficient, which is determined by the pipe length of the reducing injection system (the total length of the suction pipe 12, return pipe 13, and solution injection pipe 15) and the shape and structure of the internal liquid passage of the reducing agent supply pump 14. The pressure change difference and background pressure change slope obtained from the above calculations are only basic values ​​and need to be corrected according to the correction coefficient, such as the length of the injection pipe 15 and the structural characteristic parameters of the supply pump 14, such as the size of the return orifice. The calculation of correcting the injection background characteristic values ​​in combination with the preset system characteristic values ​​is performed using the following formula:

[0098] △Pcor=△P*r

[0099] [k 1cor k 2cor …k jcor ]=[k1,k2,..k j ]*r;

[0100] k final =∑k jcor *f j

[0101] Where ΔPcor is the corrected pressure difference, ΔP is the pressure difference before correction, [k 1cor k 2cor …k jcor [k1, k2, ..., k] represents the corrected slope change array. j [k] represents the slope change array before correction. final To calculate the eigenvalues ​​for the slope variation, k jcor For a single slope, calculate the element, f j Calculate the weight coefficient of an element for a single slope.

[0102] In one embodiment, f j It can be a sequence [1 / 2, 1 / 3, 1 / 4, ..., 1 / (j+1)], and the above formula k final =∑k jcor *f jThe specific expression can be: k final = (1 / 2)*k 1cor +(1 / 3)*k 2cor +....(1 / (j+1))*k jcor .

[0103] Optionally, the fault judgment module 530 also includes a fault determination module, used to determine whether the injection characteristics of the injector have malfunctioned based on the corrected calculation results.

[0104] In this embodiment, determining whether the injector's injection characteristics have malfunctioned based on the corrected calculation results includes:

[0105] If the corrected pressure difference ΔPcor is not within the first preset range [ΔP] min ,△P max Or, the characteristic value k is calculated by comprehensively considering the slope change. final Not within the second preset range [K] min ,K max If the jetting characteristics are suspected to be malfunctioning, then it is determined that a fault has occurred.

[0106] If the corrected pressure difference ΔPcor is not within the first preset range [ΔP] min ,△P max Furthermore, the slope change is used to comprehensively calculate the characteristic value k. final Not within the second preset range [K] min ,K max If the jetting characteristics are abnormal, then it is determined that an abnormality has occurred.

[0107] If the corrected pressure difference ΔPcor is within the first preset range [ΔP] min ,△P max Furthermore, the slope change is used to comprehensively calculate the characteristic value k. final Within the second preset range [K] min ,K max If the result is positive, then the injection characteristics are determined to be normal.

[0108] The above-described online detection device for the spray characteristics of reducing agent injectors can execute the online detection method for the spray characteristics of reducing agent injectors provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the online detection method for the spray characteristics of reducing agent injectors provided in any embodiment of the present invention. Since the online detection device for the spray characteristics of reducing agent injectors described above is an apparatus capable of executing the online detection method for the spray characteristics of reducing agent injectors in the embodiments of the present invention, those skilled in the art can understand the specific implementation methods and various variations of the online detection device for the spray characteristics of reducing agent injectors in this embodiment based on the online detection method for the spray characteristics of reducing agent injectors described in the embodiments of the present invention. Therefore, how this online detection device for the spray characteristics of reducing agent injectors implements the online detection method for the spray characteristics of reducing agent injectors in the embodiments of the present invention will not be described in detail here. Any apparatus used by those skilled in the art to implement the online detection method for the spray characteristics of reducing agent injectors in the embodiments of the present invention falls within the scope of protection of this application.

[0109] Example 4

[0110] Figure 6 A schematic diagram of a reducing agent spraying system 10, which can be used to implement embodiments of the present invention, is shown. The reducing agent spraying system may include various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, microcontrollers, and other suitable computers. The reducing agent spraying system may also include various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0111] like Figure 6As shown, the reducing agent injection system 10 includes at least one processor 111, such as an after-processing system controller (ACU), and a memory, such as a read-only memory (ROM) 112 or a random access memory (RAM) 113, communicatively connected to the at least one processor 111. The memory stores computer programs executable by the at least one processor. The processor 111 can perform various appropriate actions and processes based on the computer program stored in the ROM 112 or loaded from storage unit 118 into the RAM 113. The RAM 113 may also store various programs and data required for the operation of the reducing agent injection system 10. The processor 111, ROM 112, and RAM 113 are interconnected via a bus 114. An input / output (I / O) interface 115 is also connected to the bus 114.

[0112] Multiple components in the reducing agent spraying system 10 are connected to the I / O interface 115, including: an input unit 116, such as a keyboard, mouse, etc.; an output unit 117, such as various types of displays, speakers, etc.; a storage unit 118, such as a disk, optical disk, etc.; and a communication unit 119, such as a network card, modem, wireless transceiver, etc. The communication unit 119 allows the reducing agent spraying system 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0113] Processor 111 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 111 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the online detection method for the injection characteristics of reducing agent injectors.

[0114] In some embodiments, the online detection method for the spray characteristics of a reducing agent injector can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 118. In some embodiments, part or all of the computer program can be loaded and / or installed on the reducing agent injection system 10 via ROM 112 and / or communication unit 119. When the computer program is loaded into RAM 113 and executed by processor 111, one or more steps of the online detection method for the spray characteristics of a reducing agent injector described above can be performed. Alternatively, in other embodiments, processor 111 can be configured to perform the online detection method for the spray characteristics of a reducing agent injector by any other suitable means (e.g., by means of firmware).

[0115] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard parts (ASSPs), systems-on-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0116] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0117] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0118] To provide user interaction, the systems and techniques described herein can be implemented on a reducing agent spraying system having: a display device (e.g., a cathode ray tube display or a liquid crystal display) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the reducing agent spraying system. Other types of devices can also be used to provide user interaction; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0119] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication (e.g., communication networks) of any form or medium. Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0120] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0121] Example 5

[0122] Embodiment 5 of the present invention also provides a computer storage medium for storing a computer program, which, when executed by a computer processor, is used to perform the online detection method for the injection characteristics of the reducing agent injector described in any of the above embodiments of the present invention.

[0123] The computer storage medium of this invention can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM, or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0124] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0125] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical fiber, radio frequency (RF), or any suitable combination thereof.

[0126] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0127] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0128] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An online detection method of injection characteristics of a reductant injector, applied to a processing module of a reductant injection system, the reductant injection system further comprising an injector and a pressure acquisition module, characterized in that, The method comprises: When the reducing agent injection system meets a preset condition, freezing the control parameters of the reducing agent injection system so that the first background pressure characteristic corresponding to the injector is in a starting stable state; When the injector is controlled to start the injection action, the pressure acquisition module is controlled to acquire the background pressure change curve until the second background pressure characteristic corresponding to the injector is in an injection stable state, and the injector is controlled to stop the injection action; The injection background characteristic value of the injector injection process is calculated, and the injection background characteristic value is corrected in combination with a preset system characteristic value; The calculation of the injection background characteristic value of the injector injection process comprises: calculating the pressure difference ΔP between the background pressure from the start steady state to the injection steady state and calculating the slope change array [k1, k2, k3...k j ] between the background pressure from the start steady state to the injection steady state, Wherein, △P=p[1]-p[n], n is the last pressure value index acquired; k i = (p[i] - p[i + m]) / (m * sample rate), i is the i-th changing slope calculated, m is the number of samples spanned by the slope calculation window, where j represents the total number of slope calculations obtained, j = n - m + 1.

2. The method of claim 1, wherein, The reducing agent injection system further comprises a power supply module and a flow meter, and the preset condition comprises that the cumulative injection amount of the reducing agent injected by the injector recorded by the flow meter exceeds a set threshold, and the system power supply voltage provided by the power supply module is in a set range.

3. The method of claim 1, wherein, The background pressure change curve comprises a background pressure drop curve and a background pressure stable curve connected in time sequence.

4. The method of claim 1, wherein, The preset system characteristic value at least comprises a correction coefficient, and the correction coefficient is determined by the pipe length of the reducing injection system and the shape structure of the reducing agent supply pump.

5. The method of claim 4, wherein, The correction calculation of the injection background characteristic value in combination with the preset system characteristic value is performed by using the following formula: △Pcor=△P*r [k 1cor k 2cor …k jcor ]=[k1,k2,..k j ]*r; k final =∑k jcor *f j Wherein, r is a correction coefficient, △Pcor is a corrected pressure difference, △P is a pressure difference before correction, [k 1cor k 2cor …k jcor ] is a corrected slope change array, [k1, k2,..k j ] is a slope change array before correction, k final is a slope change comprehensive calculation characteristic value, k jcor is a single slope calculation element, f j is a weight coefficient of a single slope calculation element.

6. The method of claim 5, wherein, The judgment of whether the injection characteristic of the injector fails according to the correction calculation result comprises: If the corrected pressure difference ΔPcor is not in the first preset range or the slope change comprehensive calculation characteristic value k final is not in the second preset range, it is judged that the injection characteristic has a suspected fault. If the corrected pressure difference ΔPcor is not in the first preset range and the slope change comprehensive calculation characteristic value k final is not in the second preset range, it is determined that an abnormal failure occurs in the injection characteristic. If the corrected pressure difference ΔPcor is in the first preset range and the slope change comprehensive calculation characteristic value k final is in the second preset range, it is determined that the injection characteristic has not failed. 7.A reducing agent injector injection characteristic online detection device, which is controlled by using the reducing agent injector injection characteristic online detection method in any one of claims 1-6, comprising A pre-injection stabilization module is configured to freeze the control parameters of the reducing agent injection system when the reducing agent injection system meets a preset condition so that the first background pressure characteristic corresponding to the injector is in a starting stable state; An injection control module is configured to control the injector to start the injection action, control the pressure acquisition module to acquire the background pressure change curve, and control the injector to stop the injection action when the second background pressure characteristic corresponding to the injector is in an injection stable state; A fault judgment module is configured to calculate the injection background characteristic value of the injector injection process, and correct the injection background characteristic value in combination with a preset system characteristic value. According to the correction calculation result, whether the injection characteristic of the injector fails is judged.

8. A reductant injection system characterized by, The reducing agent injection system comprises: At least one processor; and A memory connected in communication with the at least one processor; wherein The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the reducing agent injector injection characteristic online detection method in any one of claims 1-6.

9. A computer storage medium, characterized in that The computer storage medium stores computer instructions, and the computer instructions are used to enable the processor to implement the reducing agent injector injection characteristic online detection method in any one of claims 1-6 when executed.

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