A method of monitoring the reliability of urea quality sensor measurements and related apparatus

Abstract

The application provides a urea quality sensor measurement value reliability monitoring method and related device, relates to the field of engine aftertreatment systems, and acquires actual urea injection amount consumed in hydrolysis of an SCR aftertreatment system and actual NOx consumption amount consumed in catalytic reduction reaction, calculates a real-time value of urea concentration consumed in hydrolysis according to the actual urea injection amount and the actual NOx consumption amount, acquires a urea concentration measurement value corresponding to the real-time value of urea concentration, and determines whether the urea concentration measurement value output by a urea quality sensor is reliable according to the urea concentration measurement value and the real-time value of urea concentration. Since the real-time value of urea concentration is calculated based on actual hydrolysis and catalytic reduction reaction, the calculation process is not affected by bubbles in a urea tank, the accuracy of the real-time value of urea concentration is ensured, and therefore, even if bubbles appear in the urea tank, whether the urea concentration measurement value is reliable can be accurately determined according to the real-time value of urea concentration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine aftertreatment system, in particular to a method for monitoring the reliability of urea quality sensor measurement value and related device. BACKGROUND

[0002] In the diesel engine SCR (Selective Catalytic Reduction) aftertreatment system, when the exhaust gas temperature reaches a certain value, the urea solution with a concentration of 32.5% in the urea tank is sprayed into the diesel engine exhaust pipe through the urea nozzle, and the ammonia generated by the hydrolysis of the urea solution reacts with the harmful gas NOx in the exhaust gas to reduce the harm of diesel exhaust pollutants to the atmospheric environment.

[0003] At present, the urea concentration is usually measured in real time by the urea quality sensor installed in the urea tank to determine whether the urea concentration sprayed by the urea nozzle meets the concentration requirement of 32.5%. However, a large amount of bubbles may appear in the urea tank, and the bubbles adhere to the surface of the urea quality sensor probe, resulting in inaccurate urea concentration measurement value measured by the urea quality sensor.

[0004] Therefore, there is an urgent need for a method for determining whether the urea quality sensor measurement value is reliable. SUMMARY

[0005] Therefore, the present application provides a method for monitoring the reliability of urea quality sensor measurement value and related device for determining whether the urea quality sensor measurement value is reliable, and the technical solution is as follows:

[0006] A method for monitoring the reliability of urea quality sensor measurement value, comprising:

[0007] real-time acquisition of the actual injection amount of urea consumed by hydrolysis and the actual consumption amount of NOx consumed by catalytic reduction reaction in the SCR aftertreatment system;

[0008] calculating the real-time value of the urea concentration consumed by hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx;

[0009] acquiring the urea concentration measurement value corresponding to the real-time value of the urea concentration, wherein the urea concentration measurement value is measured by a urea quality sensor;

[0010] determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time value of the urea concentration.

[0011] Optionally, the real-time actual injection amount of urea consumed in hydrolysis in the SCR aftertreatment system and the real-time actual consumption amount of NOx consumed in catalytic reduction reaction are acquired, including:

[0012] The injection period of a urea nozzle injecting urea into the SCR aftertreatment system and the nozzle duty cycle are acquired in real time;

[0013] The real-time actual injection amount of urea is calculated according to the injection period and the nozzle duty cycle;

[0014] The amount of NOx at the inlet of a catalyst in the SCR aftertreatment system and the amount of NOx at the outlet of the catalyst are acquired in real time;

[0015] The real-time actual consumption amount of NOx is calculated according to the amount of NOx at the inlet of the catalyst and the amount of NOx at the outlet of the catalyst.

[0016] Optionally, the real-time value of the concentration of urea consumed in hydrolysis is calculated according to the real-time actual injection amount of urea and the real-time actual consumption amount of NOx, including:

[0017] A pre-established urea concentration calculation model is acquired, wherein the urea concentration calculation model is a model established based on actual chemical reaction equations in the hydrolysis and the catalytic reduction reaction;

[0018] The real-time actual injection amount of urea and the real-time actual consumption amount of NOx are substituted into the urea concentration calculation model to obtain the calculated real-time value of the concentration of urea.

[0019] Optionally, the urea concentration calculation model is:

[0020]

[0021] wherein, the m act is the real-time actual injection amount of urea, the ρ Adblue is a standard urea concentration, the m NOx is the real-time actual consumption amount of NOx, the ε is the mass ratio of ammonia to NOx in the catalytic reduction reaction, and the ρ act is the real-time value of the concentration of urea.

[0022] Optionally, whether the urea concentration measurement value output by the urea quality sensor is reliable is determined according to the urea concentration measurement value and the real-time value of the concentration of urea, including:

[0023] A positive difference value of the urea concentration measurement value and the real-time value of the concentration of urea is calculated;

[0024] The positive difference value is integrated in a preset integration period to obtain an integration value;

[0025] According to the integral value, it is determined whether the urea concentration measurement value output by the urea quality sensor is reliable.

[0026] Optionally, the step of determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the integral value comprises:

[0027] determining whether the integral value is greater than a preset integral threshold value;

[0028] if yes, it is determined that the urea concentration measurement value is unreliable;

[0029] if no, it is determined that the urea concentration measurement value is reliable.

[0030] Optionally, the real-time acquisition of the actual injection amount of urea consumed by hydrolysis in the SCR aftertreatment system and the actual consumption amount of NOx consumed by catalytic reduction reaction comprises:

[0031] the real-time acquisition of the actual injection amount of urea consumed by hydrolysis in the SCR aftertreatment system and the actual consumption amount of NOx consumed by catalytic reduction reaction is performed after a preset condition is met, wherein the preset condition comprises: normal engine starting, NOx sensor readiness and normal urea injection of urea nozzle;

[0032] Before the step of determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time urea concentration value, the method further comprises:

[0033] determining whether a fluctuation value of the real-time urea concentration value within a preset time length is less than a preset fluctuation threshold value, wherein in the case that the fluctuation value is less than the preset fluctuation threshold value, the step of determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time urea concentration value is performed.

[0034] A device for monitoring the reliability of a urea quality sensor measurement value, comprising:

[0035] a real-time consumption value acquisition unit configured to acquire, in real time, an actual injection amount of urea consumed by hydrolysis in a SCR aftertreatment system and an actual consumption amount of NOx consumed by catalytic reduction reaction;

[0036] a real-time concentration value calculation unit configured to calculate, according to the actual injection amount of urea and the actual consumption amount of NOx, a real-time urea concentration value of the urea consumed by hydrolysis;

[0037] a real-time measurement value acquisition unit configured to acquire a urea concentration measurement value corresponding to the real-time urea concentration value, wherein the urea concentration measurement value is measured by a urea quality sensor;

[0038] A credibility judging unit is configured to determine whether the urea concentration measurement value output by the urea quality sensor is credible according to the urea concentration measurement value and the urea concentration real-time value.

[0039] An electronic device includes a memory and a processor;

[0040] The memory is configured to store a program;

[0041] The processor is configured to execute the program to implement each step of the urea quality sensor measurement value credibility monitoring method according to any one of the preceding embodiments.

[0042] A readable storage medium has a computer program stored thereon, and the computer program, when executed by a processor, implements each step of the urea quality sensor measurement value credibility monitoring method according to any one of the preceding embodiments.

[0043] According to the technical solution described above, the urea quality sensor measurement value credibility monitoring method provided by the present application can obtain the actual injection amount of urea consumed in the hydrolysis of the SCR aftertreatment system and the actual consumption amount of NOx consumed in the catalytic reduction reaction, calculate the urea concentration real-time value consumed in the hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx, obtain the urea concentration measurement value corresponding to the urea concentration real-time value, and determine whether the urea concentration measurement value output by the urea quality sensor is credible according to the urea concentration measurement value and the urea concentration real-time value. Since the urea concentration real-time value is calculated based on the actual hydrolysis and catalytic reduction reaction, the calculation process is not affected by the bubbles in the urea tank, and the accuracy of the urea concentration real-time value is ensured. Therefore, even if bubbles appear in the urea tank, the urea concentration measurement value can be accurately determined to be credible or not according to the urea concentration real-time value. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on the provided drawings.

[0045] Figure 1 A flowchart of a urea quality sensor measurement value credibility monitoring method provided by an embodiment of the present application;

[0046] Figure 2 A curve diagram showing the change of the urea concentration real-time value calculated according to the urea concentration calculation model over time;

[0047] Figure 3A simulation diagram of a urea quality sensor credibility monitoring strategy is provided.

[0048] Figure 4 A flowchart of another urea quality sensor measurement value credibility monitoring method provided by the embodiment of the application is shown in the figure.

[0049] Figure 5 A structure diagram of a urea quality sensor measurement value credibility monitoring device provided by the embodiment of the application is shown in the figure.

[0050] Figure 6 A hardware structure block diagram of an electronic device provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the application will be clearly and completely described in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0052] In actual application, a urea quality sensor is installed in a urea tank, and the actual amount of urea that should be sprayed by a urea nozzle can be determined according to a urea concentration measurement value output by the urea quality sensor. However, the urea quality sensor probe is affected by bubbles in the urea tank, which may cause the urea concentration measurement value to be inaccurate, and further cause the urea to be under-sprayed or over-sprayed, so that the NOx emission exceeds the standard or the urea crystallizes. Therefore, it is necessary to determine whether the urea quality sensor measurement value is credible.

[0053] The inventors of the present application thought of the following idea in the preliminary stage: when it is detected that the urea concentration measurement value output by the urea quality sensor jumps, the change of the vehicle ambient temperature signal and the urea tank temperature signal in a preset time period is obtained, and whether the urea concentration measurement value output by the urea quality sensor is credible is determined based on the change amount of the vehicle ambient temperature signal and the urea tank temperature signal in the preset time period.

[0054] However, the above scheme has the following disadvantages: first, the changes of the vehicle ambient temperature signal and the urea tank temperature signal are very slow, which results in poor real-time performance of the above scheme; second, the appearance of bubbles in the urea tank is not only caused by the change of the urea tank temperature, but also caused by the jolt of the vehicle driving, and the above preliminary stage scheme cannot solve the problem of inaccurate urea concentration measurement value caused by the jolt of the vehicle driving.

[0055] In view of the above-mentioned defects, the present inventor has made further in-depth research, and finally proposes a urea quality sensor measurement value reliability monitoring method. Next, the urea quality sensor measurement value reliability monitoring method provided by the present application will be described in detail through the following embodiments.

[0056] Please refer to Figure 1 , which shows the flowchart of the urea quality sensor measurement value reliability monitoring method provided by the embodiments of the present application. The urea quality sensor measurement value reliability monitoring method can include:

[0057] Step S101, real-time acquisition of urea actual injection amount consumed by hydrolysis in the SCR aftertreatment system and NOx actual consumption amount consumed by catalytic reduction reaction.

[0058] Those skilled in the art should understand that when the exhaust gas temperature reaches a certain value, urea will be sprayed into the exhaust gas to produce ammonia by hydrolysis, and ammonia will then undergo catalytic reduction reaction with NOx to obtain nitrogen and water.

[0059] Considering that in actual chemical reactions, urea actual injection amount, urea concentration value, and NOx actual consumption amount have a certain correlation, therefore, the present embodiment can real-time acquisition of urea actual injection amount consumed by hydrolysis in the SCR aftertreatment system and NOx actual consumption amount consumed by catalytic reduction reaction.

[0060] In one possible implementation, the process of "real-time acquisition of urea actual injection amount consumed by hydrolysis in the SCR aftertreatment system" can include: real-time acquisition of injection period and nozzle duty cycle of urea injection nozzle for injecting urea into the SCR aftertreatment system, and calculation of urea actual injection amount according to the injection period and nozzle duty cycle.

[0061] Here, the nozzle duty cycle can reflect the proportion of urea injection by the urea injection nozzle in one injection period. The larger the nozzle duty cycle, the larger the urea actual injection amount, and vice versa, the smaller the nozzle duty cycle, the smaller the urea actual injection amount.

[0062] And the injection period also has an impact on the urea actual injection amount, therefore, the present embodiment can calculate the urea actual injection amount according to the injection period and nozzle duty cycle.

[0063] Of course, in addition to the above-mentioned method of calculating the urea actual injection amount according to the injection period and nozzle duty cycle of the urea injection nozzle, the present embodiment can also use other methods to obtain the urea actual injection amount, such as through sensor measurement or by calculating the volume of urea in the urea tank, etc., which are not limited in the present application.

[0064] Optionally, the process of "real-time obtaining the actual consumption of NOx consumed in the catalytic reduction reaction in the SCR aftertreatment system" can include: real-time obtaining the amount of NOx at the inlet of the catalyst in the SCR aftertreatment system and the amount of NOx at the outlet of the catalyst, and calculating the actual consumption of NOx according to the amount of NOx at the inlet of the catalyst and the amount of NOx at the outlet of the catalyst.

[0065] It should be understood that the catalytic reduction reaction in the catalyst consumes NOx, so that the amount of NOx at the inlet of the catalyst is necessarily less than the amount of NOx at the outlet of the catalyst. Therefore, the embodiment can calculate the actual consumption of NOx according to the amount of NOx at the inlet of the catalyst and the amount of NOx at the outlet of the catalyst. Specifically, the amount of NOx at the inlet of the catalyst is subtracted from the amount of NOx at the outlet of the catalyst, and the actual consumption of NOx is obtained.

[0066] Step S102, calculating the real-time value of the urea concentration consumed by hydrolysis according to the actual injection amount of urea and the actual consumption of NOx.

[0067] In the above step, the embodiment can real-time obtain the actual injection amount of urea and the corresponding actual consumption of NOx, and the actual injection amount of urea and the actual consumption of NOx have a certain correlation with the urea concentration value. Therefore, the embodiment can calculate the urea concentration value of the urea consumed by hydrolysis according to the real-time obtained actual injection amount of urea and the corresponding actual consumption of NOx. In order to distinguish from the urea concentration measured value output by the urea quality sensor, the calculated urea concentration value is recorded as the real-time value of the urea concentration.

[0068] It is worth noting that the hydrolysis and catalytic reduction reaction in the SCR are continuous processes, and in actual application, the actual injection amount of urea consumed at each moment and the actual consumption of NOx can be different, so the real-time value of the urea concentration calculated at each moment can be different.

[0069] Step S103, obtaining the urea concentration measured value corresponding to the real-time value of the urea concentration, wherein the urea concentration measured value is measured by the urea quality sensor.

[0070] Specifically, while the actual injection amount of urea and the actual consumption of NOx are real-time obtained in step S101, the embodiment also real-time obtains the urea concentration measured value output by the urea quality sensor. Here, the "urea concentration measured value corresponding to the real-time value of the urea concentration" refers to the urea concentration measured value obtained at the same time as the real-time value of the urea concentration.

[0071] Here, the reason why the urea quality sensor can output the urea concentration measurement value is that the urea quality sensor is a sensor based on acoustic principle, according to the different speeds of ultrasonic waves in different media, by measuring the time used for emitting and receiving the reflection of the sound wave signal in a fixed distance, measuring the speed of sound in the liquid, thereby obtaining the urea concentration measurement value.

[0072] In step S104, it is determined whether the urea concentration measurement value measured by the urea quality sensor is credible according to the urea concentration measurement value and the real-time urea concentration value.

[0073] The method for monitoring the credibility of the measurement value of the urea quality sensor provided in the present application obtains the actual injection amount of urea consumed in the hydrolysis in the SCR aftertreatment system and the actual consumption amount of NOx consumed in the catalytic reduction reaction in real time, calculates the real-time urea concentration value consumed in the hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx, obtains the urea concentration measurement value corresponding to the real-time urea concentration value, and determines whether the urea concentration measurement value output by the urea quality sensor is credible according to the urea concentration measurement value and the real-time urea concentration value. Since the real-time urea concentration value is calculated based on the actual hydrolysis and catalytic reduction reaction, the calculation process is not affected by the bubbles in the urea tank, and the accuracy of the real-time urea concentration value is ensured, so that even if bubbles appear in the urea tank, the credibility of the urea concentration measurement value can be accurately determined according to the real-time urea concentration value.

[0074] In some embodiments of the present application, the process of "calculating the real-time urea concentration value consumed in the hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx" in the above step S102 is introduced.

[0075] In the present embodiment, a urea concentration calculation model can be established based on the actual chemical reaction equation in the hydrolysis and catalytic reduction reaction, and the establishment process is as follows:

[0076] Firstly, the hydrolysis equation is determined. The chemical reaction equation of urea entering the exhaust gas for hydrolysis is: (NH2)2CO + H2O → 2NH3 + CO2.

[0077] Since the molar mass of ammonia is The molar mass of urea is Then, based on the above hydrolysis equation, the mass ratio of urea to ammonia can be obtained by combining the mass conservation equation: That is, the mass of urea (here, pure urea) consumed in the hydrolysis is

[0078] Assuming that the urea water solution sprayed by the urea nozzle is standard urea concentration 32.5%, then the mass of the urea water solution with standard urea concentration consumed in the hydrolysis is

[0079] Next, the catalytic reduction reaction equations were determined. The chemical reaction equations for the catalytic reduction of ammonia and NOx include the following three equations: Equation 1 is 4NH3 + 4NO + O2 → 4N2 + 6H2O; Equation 2 is 4NH3 + 2NO + 2NO2 → 4N2 + 6H2O; Equation 3 is 4NH3 + 3NO2 → 3.5N2 + 6H2O.

[0080] Equation 1 above is the standard reaction, Equation 2 is the fast reaction, and Equation 3 is the slow reaction. The strength of the three reactions is strongly correlated with the proportion of NO2 in NOx.

[0081] Assuming the mass ratio of ammonia to NOx in the catalytic reduction reaction is... When there is no ammonia leakage in the urea injected into the SCR, the theoretical mass of urea solution required for the reaction is: Where, m InNOx The amount of NOx at the catalyst inlet, m OutNOx This indicates the amount of NOx at the catalyst outlet, as described above, m InNOx -m OutNOx This indicates the actual amount of NOx consumed.

[0082] It should be understood that the concentration of urea injected through the urea nozzle may not be the standard urea concentration. Assuming the actual amount of urea injected during hydrolysis in the SCR aftertreatment system (i.e., the actual amount of urea injected through the urea nozzle) is m... act Therefore, the urea concentration calculation model obtained according to the principle of urea equilibrium is as follows:

[0083]

[0084] In the formula, m act ρ represents the actual amount of urea injected. Adblue The standard urea concentration is 32.5%, m NOx ρ represents the actual NOx consumption, ε is the mass ratio of ammonia to NOx in the catalytic reduction reaction, and is taken as 0.43. act This is the real-time value of urea concentration.

[0085] Once a urea concentration calculation model is established, the real-time urea concentration can be calculated based on this model. Specifically, the process of "calculating the real-time urea concentration consumed by hydrolysis based on the actual urea injection rate and the actual NOx consumption" can include: obtaining a pre-established urea concentration calculation model, substituting the actual urea injection rate and the actual NOx consumption into the urea concentration calculation model, and obtaining the calculated real-time urea concentration.

[0086] For example, see Figure 2 The figure shown is a schematic diagram illustrating the change of real-time urea concentration over time, calculated based on the urea concentration calculation model.Figure 2 The horizontal axis is time, and the vertical axis is the real-time value of urea concentration.

[0087] Since the real-time value of urea concentration in the embodiment is calculated according to the amount of consumed NOx in the actual catalytic reduction reaction, and neither the catalytic reduction reaction nor the hydrolysis reaction is affected by the bubbles in the urea tank, the real-time value of urea concentration calculated by the method provided in the embodiment is more accurate.

[0088] In some other embodiments of the present application, the process of step S104 "determining whether the urea concentration measured value output by the urea quality sensor is reliable according to the urea concentration measured value and the real-time value of urea concentration" is introduced.

[0089] In an optional embodiment, whether the urea concentration measured value output by the urea quality sensor is reliable can be determined according to the real-time value of urea concentration calculated at a moment and the corresponding urea concentration measured value.

[0090] Considering that the real-time value of urea concentration calculated at a moment may have errors, in order to avoid the case that the error of the real-time value of urea concentration at a single moment adversely affects the final judgment result, preferably, the process of "determining whether the urea concentration measured value output by the urea quality sensor is reliable according to the urea concentration measured value and the real-time value of urea concentration" in the embodiment can include: calculating the positive difference value of the urea concentration measured value and the real-time value of urea concentration, integrating the positive difference value in a preset integration period to obtain an integration value, and determining whether the urea concentration measured value output by the urea quality sensor is reliable according to the integration value.

[0091] The positive difference value refers to a difference value greater than or equal to 0. Specifically, if the urea concentration measured value is greater than or equal to the real-time value of urea concentration, the positive difference value = urea concentration measured value - real-time value of urea concentration; if the urea concentration measured value is less than the real-time value of urea concentration, the positive difference value = real-time value of urea concentration - urea concentration measured value.

[0092] The process of "determining whether the urea concentration measured value output by the urea quality sensor is reliable according to the integration value" can include: determining whether the integration value is greater than a preset integration threshold value, if yes, determining that the urea concentration measured value is unreliable, and if no, determining that the urea concentration measured value is reliable.

[0093] Optionally, the embodiment can be timed by a timer, the timer starts timing from 0, and starts integrating the positive difference value at the same time, stops integrating when the timer reaches the integration period, and obtains the integration value. Taking the integration period as 100s for example, the embodiment can start integrating from 0 of the timer at the same time, stop integrating when the timing reaches 100s, obtain an integration value, and compare the integration value with a preset integration threshold value (for example, 300). If the integration value is greater than the integration threshold value, it indicates that the urea concentration measurement value output by the urea quality sensor has deviation, at this time, the urea quality sensor untrusted fault is reported. Otherwise, if the integration value is not greater than the integration threshold value, it indicates that the urea concentration measurement value output by the urea quality sensor does not have deviation, then it is determined that the urea concentration measurement value output by the urea quality sensor is trusted. Thereafter, the timer is cleared, and then a new integration and timing of a period is started.

[0094] Referring to Figure 3 Fig. 2 shows a simulation diagram of the urea quality sensor trustworthiness monitoring strategy, (a) is a schematic diagram of the urea concentration measurement value and the urea concentration real-time value, (b) is a schematic diagram of the integration period, and the two vertical lines represent an integration period, and (c) is a schematic diagram of the integration value and the integration threshold value in the integration period. As shown in (a) of Fig. 2, the urea concentration measurement value is the urea concentration value output by the urea quality sensor, and the urea concentration real-time value is the urea concentration value measured by the urea concentration sensor. Figure 3 As shown in (b) of Fig. 2, an integration period is 100s, as shown in (c) of Fig. 2, in the integration period of 1000-1100, the integration value is greater than the preset integration threshold value, at this time, it is determined that the urea concentration measurement value output by the urea quality sensor is untrusted. In other integration periods, the integration value is less than the integration threshold value, then it can be determined that the urea concentration measurement value output by the urea quality sensor is trusted. Figure 3 As shown in (b) of Fig. 2, an integration period is 100s, as shown in (c) of Fig. 2, in the integration period of 1000-1100, the integration value is greater than the preset integration threshold value, at this time, it is determined that the urea concentration measurement value output by the urea quality sensor is untrusted. In other integration periods, the integration value is less than the integration threshold value, then it can be determined that the urea concentration measurement value output by the urea quality sensor is trusted.

[0095] In summary, the embodiment judges whether the urea concentration measurement value output by the urea quality sensor is trusted by counting the positive difference value between the urea concentration measurement value and the urea concentration real-time value in a period of time, and determining the integration value calculated based on the positive difference value. Compared with the judgment method by the positive difference value at a single time point, the judgment result of the embodiment is more reliable.

[0096] In some embodiments of the present application, in order to avoid the situation that the urea real-time injection amount and the NOx consumption amount cannot be obtained or the urea real-time injection amount and the NOx consumption amount obtained are incorrect, the embodiment can obtain the urea actual injection amount consumed by hydrolysis in the SCR aftertreatment system and the NOx actual consumption amount consumed by catalytic reduction reaction after the preset condition is reached.

[0097] Optionally, the preset condition includes: the engine is normally started, the NOx sensor is ready (i.e. can measure the NOx concentration in the exhaust gas), and the urea nozzle normally sprays urea.

[0098] Further, after the actual urea injection amount and the actual NOx consumption amount are acquired in real time, the real-time urea concentration value can be calculated according to the formula (1).

[0099] It should be understood that in actual application, when the real-time urea concentration value is calculated according to the formula (1), the real-time urea concentration value may fluctuate greatly, which may be caused by inaccurate calculation of the real-time urea concentration value or instability of the overall system. If the real-time urea concentration value is used to determine whether the urea concentration measurement value is reliable at this time, it is very likely that an incorrect judgment will occur.

[0100] In order to improve the accuracy and reliability of the judgment result, preferably, the embodiment can first determine whether the fluctuation value of the real-time urea concentration value calculated according to the formula (1) within a preset time length is less than a preset fluctuation threshold, for example, whether the fluctuation of the calculated real-time urea concentration value within 20s is less than 1%, if yes, then the subsequent step S104 can be performed to determine whether the urea concentration measurement value output by the urea quality sensor is reliable.

[0101] Referring to Figure 4 Another flowchart of a method for monitoring the reliability of a urea quality sensor measurement value provided by the embodiment of the present application is shown, and the method comprises the following steps:

[0102] Step S201, determine whether a preset condition is met, if yes, execute step S202.

[0103] Specifically, the embodiment can determine whether a preset condition is met when it is necessary to monitor the reliability of the urea concentration measurement value output by the urea quality sensor, if yes, execute step S202, if not, wait for a period of time and then determine whether the preset condition is met again, until the preset condition is met, execute step S202.

[0104] Optionally, the preset condition comprises: normal start of the engine, readiness of the NOx sensor (i.e. capable of measuring the NOx concentration in the exhaust gas) and normal injection of urea by the urea nozzle.

[0105] Of course, the preset condition can also be other, which is not limited in the present application.

[0106] Step S202, calculate the real-time urea concentration value by using a pre-established urea concentration calculation model.

[0107] Specifically, the embodiment acquires the actual urea injection amount consumed by hydrolysis in the SCR aftertreatment system and the actual NOx consumption amount consumed by catalytic reduction reaction in real time, and then substitutes the actual urea injection amount and the actual NOx consumption amount into the urea concentration calculation model to obtain the calculated real-time urea concentration value.

[0108] It should be noted that the process of calculating the real-time value of the urea concentration is continuous, and therefore a plurality of real-time values of the urea concentration can be calculated at a plurality of times.

[0109] In step S203, it is determined whether the real-time value of the urea concentration is stable. If yes, step S204 is performed.

[0110] Specifically, the embodiment can determine whether the fluctuation value of the real-time value of the urea concentration within a preset time length is less than a preset fluctuation threshold. If yes, it indicates that the real-time value of the urea concentration is stable, and then step S204 is performed. If no, it indicates that the real-time value of the urea concentration is not stable, and then the real-time value of the urea concentration is continuously calculated until the real-time value of the urea concentration is stable, and then step S204 is entered.

[0111] In step S204, a timer T starts timing, and the positive difference value is integrated during the timing.

[0112] Here, the positive difference value refers to the absolute value of the difference between the urea concentration measurement value and the real-time value of the urea concentration.

[0113] In step S205, it is determined whether the timer T reaches the integration period. If yes, step S206 is performed.

[0114] Specifically, if the timer T reaches the integration period, the integration is ended, the integration value in the current integration period is obtained, and then step S206 is performed. If the timer T does not reach the integration period, the integration is continuously performed until the integration period is reached, and then step S206 is performed.

[0115] In step S206, it is determined whether the integration value is greater than the integration threshold. If yes, it is determined that the urea concentration measurement value output by the urea quality sensor is not reliable. If no, the timer T is cleared, and the integration and timing of the next integration period are started.

[0116] In the above embodiment, after the system as a whole is stable, the actual urea concentration (i.e., the real-time value of the urea concentration) is estimated according to the consumed NOx in the SCR, and the reliability of the urea quality sensor measurement value is further determined according to the real-time value of the urea concentration. Even if there are bubbles in the urea tank causing the urea concentration to jump, the reliability of the urea quality sensor measurement value can still be accurately determined, which provides an effective basis for subsequent urea injection by the urea nozzle, and avoids the situation of less injection or over-injection of urea, thereby providing a better experience.

[0117] The embodiment of the present application also provides a urea quality sensor measurement value reliability monitoring device. The urea quality sensor measurement value reliability monitoring device provided by the embodiment of the present application is described below, and the urea quality sensor measurement value reliability monitoring device described below can be mutually referred to with the urea quality sensor measurement value reliability monitoring method described above.

[0118] Referring to Figure 5 , a structure schematic diagram of the urea quality sensor measurement value reliability monitoring device provided by the embodiments of the present application is shown, as Figure 5 shown, the urea quality sensor measurement value reliability monitoring device can include: a real-time consumption value acquisition unit 11, a real-time concentration value calculation unit 12, a real-time measurement value acquisition unit 13, and a reliability judgment unit 14.

[0119] The real-time consumption value acquisition unit 11 is configured to acquire the actual urea injection amount consumed by hydrolysis and the actual NOx consumption amount consumed by catalytic reduction reaction in the SCR aftertreatment system in real time.

[0120] The real-time concentration value calculation unit 12 is configured to calculate the real-time urea concentration value consumed by hydrolysis according to the actual urea injection amount and the actual NOx consumption amount.

[0121] The real-time measurement value acquisition unit 13 is configured to acquire a urea concentration measurement value corresponding to the real-time urea concentration value, wherein the urea concentration measurement value is measured by a urea quality sensor.

[0122] The reliability judgment unit 14 is configured to determine whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time urea concentration value.

[0123] In a possible implementation, the process that the real-time consumption value acquisition unit acquires the actual urea injection amount consumed by hydrolysis and the actual NOx consumption amount consumed by catalytic reduction reaction in the SCR aftertreatment system in real time can include:

[0124] acquiring the injection period and the nozzle duty cycle of a urea nozzle injecting urea into the SCR aftertreatment system in real time;

[0125] calculating the actual urea injection amount according to the injection period and the nozzle duty cycle;

[0126] acquiring the NOx amount at the inlet of a catalyst in the SCR aftertreatment system and the NOx amount at the outlet of the catalyst in real time;

[0127] calculating the actual NOx consumption amount according to the NOx amount at the inlet of the catalyst and the NOx amount at the outlet of the catalyst.

[0128] In a possible implementation, the process that the real-time concentration value calculation unit calculates the real-time urea concentration value consumed by hydrolysis according to the actual urea injection amount and the actual NOx consumption amount can include:

[0129] obtain a pre-established urea concentration calculation model, wherein the urea concentration calculation model is a model established based on actual chemical reaction equations in hydrolysis and catalytic reduction reactions;

[0130] substitute the actual urea injection amount and the actual NOx consumption amount into the urea concentration calculation model to obtain a calculated urea concentration real-time value.

[0131] In a possible implementation, the urea concentration calculation model is as follows: wherein m act is the actual urea injection amount, p Adblue is a standard urea concentration, m NOx is the actual NOx consumption amount, ε is a mass ratio of ammonia to NOx in the catalytic reduction reaction, and p act is the urea concentration real-time value.

[0132] In a possible implementation, the process in which the credibility determination unit determines whether the urea concentration measurement value output by the urea quality sensor is credible according to the urea concentration measurement value and the urea concentration real-time value can include:

[0133] calculating a positive difference between the urea concentration measurement value and the urea concentration real-time value;

[0134] integrating the positive difference in a preset integration period to obtain an integration value;

[0135] determining whether the urea concentration measurement value output by the urea quality sensor is credible according to the integration value.

[0136] In a possible implementation, the process in which the credibility determination unit determines whether the urea concentration measurement value output by the urea quality sensor is credible according to the integration value can include:

[0137] determining whether the integration value is greater than a preset integration threshold value;

[0138] if yes, determining that the urea concentration measurement value is not credible;

[0139] if no, determining that the urea concentration measurement value is credible.

[0140] In a possible implementation, the process in which the real-time consumption value obtaining unit obtains the actual urea injection amount consumed in hydrolysis in the SCR aftertreatment system and the actual NOx consumption amount consumed in catalytic reduction reaction can include: obtaining the actual urea injection amount consumed in hydrolysis in the SCR aftertreatment system and the actual NOx consumption amount consumed in catalytic reduction reaction in real time after a preset condition is met, wherein the preset condition includes: normal engine starting, NOx sensor readiness, and normal urea injection of the urea nozzle.

[0141] Correspondingly, the urea quality sensor measurement value reliability monitoring device provided by the embodiment also can comprise a fluctuation condition judging unit.

[0142] The fluctuation condition judging unit is configured to judge whether the fluctuation value of the urea concentration real-time value within a preset time length is less than a preset fluctuation threshold value before the reliability judging unit, and the reliability judging unit is executed when the fluctuation value is less than the preset fluctuation threshold value.

[0143] The embodiment of the present application also provides an electronic device. Figure 6 A hardware structure block diagram of the electronic device is shown, referring to Figure 6 The hardware structure of the electronic device can comprise at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4.

[0144] In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3 and the communication bus 4 is at least one, and the processor 1, the communication interface 2 and the memory 3 complete the communication among each other through the communication bus 4.

[0145] The processor 1 can be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application, etc.

[0146] The memory 3 can contain a high-speed RAM memory, and can also include a non-volatile memory, etc., such as at least one disk memory.

[0147] The memory 3 stores a program, and the processor 1 can call the program stored in the memory 3, and the program is used for:

[0148] Real-time acquisition of the actual urea injection amount consumed in hydrolysis in the SCR aftertreatment system, and the actual NOx consumption amount consumed in catalytic reduction reaction;

[0149] According to the actual urea injection amount and the actual NOx consumption amount, the urea concentration real-time value consumed in hydrolysis is calculated;

[0150] Acquisition of the urea concentration measurement value corresponding to the urea concentration real-time value, wherein the urea concentration measurement value is measured by a urea quality sensor;

[0151] According to the urea concentration measurement value and the urea concentration real-time value, it is determined whether the urea concentration measurement value output by the urea quality sensor is reliable.

[0152] Optionally, the refinement function and the extension function of the program can refer to the description above.

[0153] The embodiment of the present application further provides a readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the method for monitoring the credibility of the measurement value of the urea quality sensor.

[0154] Optionally, the refinement function and the extension function of the program can refer to the description above.

[0155] Finally, it should be noted that in this document, relational terms such as and or second and the like are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between or among such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations 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 can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0156] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other.

[0157] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of monitoring the reliability of urea quality sensor measurements, characterized by, The method comprises the following steps: real-time acquisition of actual injection amount of urea consumed in hydrolysis in an SCR aftertreatment system and actual consumption amount of NOx consumed in catalytic reduction reaction; calculation of real-time value of urea concentration consumed in hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx; acquisition of urea concentration measurement value corresponding to the real-time value of urea concentration, wherein the urea concentration measurement value is measured by a urea quality sensor, and the urea concentration measurement value is acquired at the same time as the real-time value of urea concentration; determination of whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time value of urea concentration; wherein the determination of whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the real-time value of urea concentration comprises: calculation of positive difference value of the urea concentration measurement value and the real-time value of urea concentration; integration of the positive difference value in a preset integration period to obtain an integration value; determination of whether the urea concentration measurement value output by the urea quality sensor is reliable according to the integration value; wherein the determination of whether the urea concentration measurement value output by the urea quality sensor is reliable according to the integration value comprises: determination of whether the integration value is greater than a preset integration threshold value; if yes, it is determined that the urea concentration measurement value is unreliable; if no, it is determined that the urea concentration measurement value is reliable.

2. The method of monitoring the reliability of urea quality sensor measurements according to claim 1, characterized in that The real-time acquisition of actual injection amount of urea consumed in hydrolysis in an SCR aftertreatment system and actual consumption amount of NOx consumed in catalytic reduction reaction comprises: real-time acquisition of injection period and nozzle duty cycle of a urea injection nozzle injecting urea into the SCR aftertreatment system; calculation of the actual injection amount of urea according to the injection period and the nozzle duty cycle; real-time acquisition of NOx amount at the inlet of a catalyst in the SCR aftertreatment system and NOx amount at the outlet of the catalyst; calculation of the actual consumption amount of NOx according to the NOx amount at the inlet of the catalyst and the NOx amount at the outlet of the catalyst.

3. The method of monitoring the reliability of urea quality sensor measurements according to claim 1, characterized in that, The calculation of the real-time value of urea concentration consumed in hydrolysis according to the actual injection amount of urea and the actual consumption amount of NOx comprises: acquisition of a urea concentration calculation model established in advance, wherein the urea concentration calculation model is a model established based on actual chemical reaction equations in the hydrolysis and the catalytic reduction reaction; substitution of the actual injection amount of urea and the actual consumption amount of NOx into the urea concentration calculation model to obtain the calculated real-time value of urea concentration.

4. The method of monitoring the reliability of urea quality sensor measurements according to claim 3, characterized in that, The urea concentration calculation model is: ； wherein the is the actual injection amount of urea, the is the standard urea concentration, the is the actual consumption amount of NOx, the is the mass ratio of ammonia to NOx in the catalytic reduction reaction, the is the real-time value of the urea concentration.

5. The method of claim 1 to 4, wherein The real-time acquisition of actual injection amount of urea consumed in hydrolysis in an SCR aftertreatment system and actual consumption amount of NOx consumed in catalytic reduction reaction comprises: real-time acquisition of actual injection amount of urea consumed in hydrolysis in an SCR aftertreatment system and actual consumption amount of NOx consumed in catalytic reduction reaction after a preset condition is reached, wherein the preset condition comprises normal engine start, NOx sensor readiness and normal urea injection of a urea injection nozzle. Before the step of determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the urea concentration real-time value, the method further comprises: determining whether a fluctuation value of the urea concentration real-time value within a preset time length is less than a preset fluctuation threshold value, wherein the step of determining whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the urea concentration real-time value is performed in the case that the fluctuation value is less than the preset fluctuation threshold value.

6. A device for monitoring the reliability of urea quality sensor measurements for performing the method of any one of claims 1 to 5, characterized in that The method comprises: a real-time consumption value acquisition unit configured to acquire a urea actual injection amount consumed by hydrolysis in the SCR aftertreatment system and a NOx actual consumption amount consumed by catalytic reduction reaction in real time; a real-time concentration value calculation unit configured to calculate a urea concentration real-time value of the urea consumed by hydrolysis according to the urea actual injection amount and the NOx actual consumption amount; a real-time measurement value acquisition unit configured to acquire a urea concentration measurement value corresponding to the urea concentration real-time value, wherein the urea concentration measurement value is measured by a urea quality sensor, and the urea concentration measurement value and the urea concentration real-time value are acquired at the same time; a reliability determination unit configured to determine whether the urea concentration measurement value output by the urea quality sensor is reliable according to the urea concentration measurement value and the urea concentration real-time value.

7. An electronic device, comprising: comprise a memory and a processor; the memory is configured to store a program; the processor is configured to execute the program to implement each step of the urea quality sensor measurement value reliability monitoring method according to any one of claims 1-5.

8. A readable storage medium, having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements each step of the urea quality sensor measurement value reliability monitoring method according to any one of claims 1-5.

Images