System and method for detecting concentration of urea for vehicle

Abstract

This invention relates to a vehicle urea concentration detection system, comprising a data acquisition unit, a urea concentration calculation unit, and a data storage unit. The invention also relates to a method for detecting vehicle urea concentration, comprising the steps of: acquiring a urea injection quantity correction coefficient, a urea mass sensor reading, and data from the data storage unit; determining the validity of the urea mass sensor reading based on the urea mass sensor reading compared to the concentration change of the previous urea injection and the change of the urea injection quantity correction coefficient after two urea injections; if valid, using the urea mass sensor value as the urea concentration value for the current injection; if invalid, calculating the urea concentration value for the current injection; storing it in the data storage unit; and iteratively executing the method. This invention can obtain accurate urea concentrations for urea aqueous solutions of any concentration; it solves the problem of inaccurate urea mass sensor readings caused by injecting other liquids of similar density, bubbles, or urea crystals; and it does not increase the risk of vehicle emissions exceeding standards.

Description

Technical Field

[0001] This invention relates to the field of engine exhaust gas purification technology, and more specifically to a system and method for detecting the concentration of urea in vehicles. Background Technology

[0002] With the upgrading of diesel engine emission regulations, the requirements for engine aftertreatment systems are becoming increasingly stringent. Selective catalytic reduction (SCR) technology, as the mainstream technology for solving nitrogen oxide emissions, generally uses a 32.5% urea aqueous solution as a reducing agent. Regulations stipulate that each manufacturer must set a minimum acceptable reactant concentration (CDmin). Reactants below this concentration are considered unacceptable reactants. When the OBD system detects that the vehicle is using urea, which is considered an unacceptable reactant, the driver warning system must be activated. The vehicle control system should be able to adapt to different concentrations of urea solution above CDmin. The vehicle control system will correct the urea injection quantity. When there is a risk of decreased SCR efficiency, the urea injection correction coefficient will be gradually increased to increase the urea injection quantity. When there is NH3 leakage, the urea injection correction coefficient will be gradually decreased to reduce the urea injection quantity. Ultimately, this ensures that NOx and other emissions always meet regulatory requirements.

[0003] Currently, the mainstream urea mass sensors primarily measure the density of urea solutions by detecting the different propagation speeds of ultrasound waves in liquids of varying densities, thus determining the urea concentration. However, in practical use, urea mass sensor readings are easily affected by air bubbles or urea crystals near the probe, leading to inaccurate readings. Furthermore, if a liquid with a density approximately similar to a reference urea solution is added, the sensor may fail to accurately identify it, potentially causing false alarms and impacting the customer's driving experience and travel efficiency.

[0004] A typical prior art example is Chinese invention application CN116085100A, entitled "A Method for Diagnosing Urea Concentration in Diesel Engines." This application discloses a method for diagnosing urea concentration in diesel engines, in which a urea quality sensor is installed on the aftertreatment device and communicates with the engine ECU. The engine ECU determines whether the concentration exceeds the CDmin threshold based on data from the urea quality sensor. The engine ECU also determines whether the concentration exceeds the CDmin efficiency threshold based on the aftertreatment SCR conversion efficiency. Finally, the engine diagnoses the urea concentration by combining the CDmin concentration threshold and the CDmin efficiency threshold. This invention uses SCR conversion efficiency as a key condition for diagnosing urea concentration (CDmin). By monitoring the SCR conversion efficiency, it avoids misdiagnosis of urea concentration caused by inaccurate measurements from the urea concentration sensor.

[0005] A typical prior art example is Chinese invention application CN115506878A, entitled "Detection Method and Detection System for False Alarms of Urea Concentration Sensor, Engine," which discloses a method and system for detecting false alarms of a urea concentration sensor and an engine, relating to the field of engine detection technology. When the urea concentration detected by the urea concentration sensor is not equal to a threshold, urea injection is stopped, and the sensor is checked to determine if it is a false alarm. The detection method includes the following steps: injecting urea at a set injection volume and obtaining a measured value of downstream NOx emissions; calculating the theoretical value of NOx participating in the redox reaction based on the set injection volume and the urea concentration detected by the urea concentration sensor; calculating the theoretical value of downstream NOx emissions based on the upstream NOx emissions and the theoretical value of NOx participating in the redox reaction; calculating the difference between the theoretical value of downstream NOx emissions and the measured value of downstream NOx emissions; determining whether the difference is within a first preset range; if not, the urea concentration sensor is determined to be a false alarm.

[0006] A typical prior art example is Chinese invention application CN113847130A, entitled "A Method for Detecting Urea Concentration," which discloses a method for detecting urea concentration capable of detecting urea concentration under different operating conditions and within different temperature ranges. When the temperature is below the freezing temperature of the urea solution, the most recently acquired urea concentration is determined as the current urea concentration. When the temperature is above the freezing temperature of the urea solution, the method acquires the actual urea concentration, the liquid level difference, and the duration of the liquid level difference under the corresponding operating conditions. The current urea concentration is determined based on the comparison results of the liquid level difference ΔH with a liquid level difference threshold range and the duration t with a time threshold range.

[0007] A typical prior art example is Chinese invention application CN113294230A, entitled "Urea Solution Concentration Monitoring Method, Device and SCR Post-processing System," which discloses a method for monitoring urea solution concentration. This method includes: determining whether there is urea solution in the urea tank; when it is determined that there is urea solution in the urea tank, determining whether the urea concentration of the urea solution is within a concentration threshold range; if the urea concentration is not within the concentration threshold range, determining the stability of the urea solution level in the urea tank; if the urea solution level is unstable, determining whether the urea solution in the urea tank is being added; if it is determined that the urea solution in the urea tank is being added, locking the previously detected urea concentration, and after a preset locking time, re-determining whether the urea concentration of the urea solution is within the threshold range.

[0008] A typical prior art example is Chinese invention application CN115683940A, entitled "Vehicle Urea Concentration Detection Device and Method," which discloses a vehicle urea concentration detection device and method. The method calculates the density of the urea solution based on the actual liquid level of the urea solution at the location of the pressure detection unit and the pressure exerted on the bottom wall of the urea tank. Then, it calculates the concentration of the urea solution based on the density of the urea solution and the density of water. Even if bubbles are generated in the urea solution during vehicle operation or urea refilling, the number of bubbles has a negligible impact on the height of the urea solution. Furthermore, because urea has high solubility in water, the volume change of the solution before and after dissolving urea in water is small. Compared to the influence of bubbles on the measurement results of the ultrasonic urea quality sensor, the change in solution volume before and after urea dissolves in water is negligible. Therefore, the calculated concentration of the urea solution has high measurement accuracy.

[0009] The shortcomings of existing technology are:

[0010] The patent application "A method for diagnosing urea concentration in a diesel engine" can only identify cases where the concentration of urea solution is much lower than CDmin. However, for cases where the concentration of urea solution is near or higher than CDmin, the vehicle control system needs to adapt to the urea solution according to regulations, and the SCR efficiency will not decrease significantly. Therefore, this method cannot obtain an accurate urea concentration. It can only distinguish whether the sensor is falsely reporting in the specific case where the urea concentration is significantly lower than CDmin, and its scope of application is limited.

[0011] The solution described in the patent application "Detection Method and Detection System for False Alarms of Urea Concentration Sensor, Engine" supplements the deficiencies of the patent "A Method for Diagnosing Urea Concentration in a Diesel Engine" and can be used to obtain relatively accurate urea concentration. However, when the vehicle implements this solution, it is necessary to stop urea injection and then inject at a fixed ammonia-nitrogen ratio, which temporarily shields the normal urea injection logic. This poses a high risk of causing the vehicle's emissions to exceed the standard. Even if the false alarm of the urea quality sensor is eventually discovered, there is still a high probability of SCR low efficiency failure or NH3 leakage failure, which will increase the vehicle failure rate.

[0012] Patent applications “A method for detecting urea concentration” and “A method, device and SCR post-processing system for monitoring urea solution concentration” help reduce false alarms caused by bubbles, crystals and other factors in the urea quality sensor and improve the validity of sensor data. However, the sensor itself cannot identify other liquids with similar densities, so its applicability is still limited.

[0013] The patent application "Vehicle Urea Concentration Detection Device and Vehicle Urea Concentration Detection Method" calculates the concentration of urea by accurately calculating the density of the urea aqueous solution. Similar to the previous two patents, it can accurately obtain the concentration of the urea aqueous solution. However, it is not applicable to cases where other liquids with similar densities are added. Summary of the Invention

[0014] To address the aforementioned problems, this invention provides a vehicle urea concentration detection system and method. Its purpose is not only to identify situations where the urea aqueous solution concentration is far below CDmin, but also to obtain accurate urea concentrations when the urea aqueous solution concentration is near or above CDmin; it does not increase the risk of vehicle emissions exceeding standards; and it can identify situations where other liquids of similar density have been added.

[0015] To solve the above problems, the technical solution provided by the present invention is as follows:

[0016] A vehicle urea concentration detection system includes a data acquisition unit, a urea concentration calculation unit, and a data storage unit; wherein:

[0017] The data acquisition unit is used to acquire raw data; the raw data includes urea injection volume correction coefficient, urea mass sensor reading, and urea concentration value.

[0018] The urea concentration calculation unit is used to calculate the urea concentration value after this urea injection based on the raw data collected by the data acquisition unit.

[0019] The data storage unit is used to store the urea injection volume correction coefficient and the urea concentration value after this urea injection.

[0020] Preferably, the urea injection volume correction coefficient includes the urea injection volume correction coefficient after this urea injection and the urea injection volume correction coefficient stored after the last urea injection; wherein:

[0021] The urea injection volume correction coefficient stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read;

[0022] Once the correction coefficient for the urea injection volume after the current urea injection is collected and used by the urea concentration calculation unit, the correction coefficient for the current urea injection volume after the current urea injection is written into the data storage unit, overwriting the correction coefficient for the urea injection volume stored after the previous urea injection.

[0023] Preferably, the urea concentration value includes the urea concentration value after this urea injection and the urea concentration value stored after the last urea injection; wherein:

[0024] The urea concentration value stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read;

[0025] Once the urea concentration value after the current urea injection is collected and used by the urea concentration calculation unit, the urea concentration value after the current urea injection is written into the data storage unit, overwriting the urea concentration value stored after the previous urea injection.

[0026] A method for detecting vehicle urea concentration using a vehicle urea concentration detection system includes the following steps:

[0027] S100. Monitor in real time whether the vehicle is adding urea; then, based on the monitoring results, perform the following operations:

[0028] If the vehicle has not been refilled with urea, return and execute S100 again from the beginning;

[0029] If the vehicle is being refilled with urea for the first time, start the timer to begin accumulating the vehicle's running time; then execute S200.

[0030] S200. Compare the accumulated vehicle running time with a manually preset first time threshold; then perform the following operations based on the comparison result:

[0031] If the vehicle running time is less than the first time threshold, return and execute S200 again;

[0032] If the vehicle running time is not less than the first time threshold, then collect the urea injection quantity correction coefficient at the current moment and the reading of the urea quality sensor at the current moment; then execute S300.

[0033] S300. Calculate the ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution;

[0034] S400. Determine whether the reading of the urea mass sensor is valid; then, based on the determination result, perform the following operations:

[0035] If the determination result is that the reading of the urea mass sensor is valid, then the reading of the urea mass sensor is assigned to the current urea concentration value; then S500 is executed;

[0036] If the determination result is that the reading of the urea mass sensor is invalid, then the calculated urea concentration value is assigned to the current urea concentration value; then S500 is executed;

[0037] S500. Store the urea injection volume correction coefficient collected in S200 at the current moment into the data storage unit, as the urea injection volume correction coefficient after the last urea injection.

[0038] The current urea concentration value obtained by S400 is stored in the data storage unit as the urea concentration value after the last urea injection; then S600 is executed.

[0039] S600. Monitor the vehicle again in real time to see if urea is being added; then, based on the monitoring results, perform the following operations:

[0040] If the vehicle has not been refilled with urea, return and execute S600 from the beginning again;

[0041] If the vehicle is refilled with urea, the timer is restarted to begin accumulating the vehicle's running time again; then S700 is executed.

[0042] S700. Compare the accumulated vehicle running time with a manually preset second time threshold; then perform the following operations based on the comparison result:

[0043] If the vehicle running time is less than the second time threshold, return and execute S700 again;

[0044] If the vehicle running time is not less than the second time threshold, the urea injection quantity correction coefficient and the urea quality sensor reading at the current moment are collected; then the urea injection quantity correction coefficient and the urea concentration value after the last urea injection are read from the data storage unit; then S800 is executed.

[0045] S800. Calculate the ratio of the reading measured by the urea mass sensor to the urea concentration value after the last urea injection in the data storage unit; then execute S900;

[0046] S900. Determine whether the reading of the urea mass sensor is valid; then, based on the determination result, perform the following operations:

[0047] If the determination result is that the reading of the urea mass sensor is valid, then the reading of the urea mass sensor is assigned to the current urea concentration value; then S1000 is executed;

[0048] If the determination result is that the reading of the urea quality sensor is invalid, the current urea concentration value is calculated based on the relationship between the change ratio of the urea injection volume correction coefficient obtained after the two most recent urea injections and the ratio of the urea concentration value; then S1000 is executed.

[0049] S1000. Store the urea injection volume correction coefficient collected in S700 at the current moment into the data storage unit, as the urea injection volume correction coefficient after the last urea injection.

[0050] The current urea concentration value obtained by S900 is stored in the data storage unit as the urea concentration value after the last urea injection; then S1100 is executed.

[0051] S1100. Iteratively execute S600 to S1000 until the urea injection quantity correction coefficient is no longer within the range of the manually preset urea injection quantity correction coefficient, or a low SCR efficiency fault occurs, or a high urea consumption fault occurs, or a low urea consumption fault occurs, then execute S1200.

[0052] S1200. Reset the urea concentration value stored in the data storage unit to 32.5% and lock it; reset the urea injection volume correction coefficient stored in the data storage unit to 1 and lock it; then execute S1300;

[0053] S1300. Check whether the urea injection quantity correction coefficient has returned to the range of the urea injection quantity correction coefficient, and whether the low SCR efficiency fault, high urea consumption fault, and low urea consumption fault have disappeared; then, based on the check results, perform the following operations:

[0054] If the urea injection quantity correction coefficient returns to the range of the urea injection quantity correction coefficient, and the low SCR efficiency fault disappears, and the high urea consumption fault disappears, and the low urea consumption fault disappears, then return to and re-execute S100.

[0055] If the urea injection quantity correction coefficient does not return to the range of the urea injection quantity correction coefficient, or the low SCR efficiency fault does not disappear, or the high urea consumption fault does not disappear, or the low urea consumption fault does not disappear, then return to and re-execute S1300.

[0056] Preferably, the first time threshold ranges from 1 hour to 3 hours.

[0057] Preferably, the ratio of the reading measured by the urea mass sensor in S300 to the concentration of the standard automotive urea solution is expressed by the following formula:

[0058] B1 = ω1 / 32.5%

[0059] Wherein: B1 is the ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution; ω1 is the reading measured by the urea mass sensor.

[0060] Preferably, determining whether the reading of the urea quality sensor is valid in step S400 specifically includes the following steps:

[0061] S410. Calculate the first reference value, expressed as follows:

[0062] C1 = |A1 / B1-1|

[0063] Wherein: C1 is the first reference value; A1 is the correction coefficient for the urea injection amount collected at the current moment in S200;

[0064] S420. Compare the first reference value with a manually preset first reference value threshold; then perform the following operations based on the comparison result:

[0065] If the first reference value is less than the first reference value threshold, the reading of the urea quality sensor is determined to be valid.

[0066] If the first reference value is not less than the first reference value threshold, then the reading of the urea quality sensor is determined to be invalid.

[0067] Preferably, the calculated urea concentration is expressed by the following formula:

[0068] ω c =32.5% / A1

[0069] Where: ω c This is the calculated value of the urea concentration.

[0070] Preferably, the ratio of the reading measured by the urea quality sensor in S800 to the urea concentration value in the data storage unit after the last urea addition is expressed by the following formula:

[0071] B2=ω2 / ω

[0072] Wherein: B2 is the ratio of the reading measured by the urea quality sensor to the urea concentration value after the last urea injection in the data storage unit; ω2 is the reading of the urea quality sensor in S700; ω is the urea concentration value after the last urea injection read from the data storage unit in S700.

[0073] Preferably, determining whether the reading of the urea quality sensor is valid in step S900 specifically includes the following steps:

[0074] S910. Calculate the second reference value, expressed as follows:

[0075] C2 = |A2 / (A*B2)-1|

[0076] Wherein: C2 is the second reference value; A2 is the correction coefficient for the urea injection volume at the current moment collected in S700; A is the correction coefficient for the urea injection volume after the last urea injection read from the data storage unit in S700;

[0077] S920. Compare the second reference value with a manually preset second reference value threshold; then perform the following operations based on the comparison result:

[0078] If the second reference value is less than the second reference value threshold, the reading of the urea mass sensor is determined to be valid.

[0079] If the second reference value is not less than the second reference value threshold, the reading of the urea mass sensor is determined to be invalid.

[0080] In S900, the current urea concentration is calculated based on the relationship between the ratio of the change ratio of the urea injection volume correction coefficient obtained after the two most recent urea injections and the ratio of the urea concentration value, expressed by the following formula:

[0081] ω'=ω*A / A2

[0082] Wherein: ω' is the urea concentration value mentioned in this study.

[0083] Compared with the prior art, the present invention has the following advantages:

[0084] 1. Because the present invention can not only identify cases where the concentration of urea aqueous solution is much lower than CDmin, but also obtain accurate urea concentrations when the concentration of urea aqueous solution is near or higher than CDmin, it greatly expands the application field compared with the prior art.

[0085] 2. Since the present invention does not require stopping urea injection before injecting at a fixed ammonia-nitrogen ratio, nor does it require temporarily blocking the normal urea injection logic, there is no risk of vehicle emissions exceeding the standard, and the source of the increase in vehicle failure rate caused by low SCR efficiency or NH3 leakage is eliminated.

[0086] 3. Because the present invention can also identify cases where other liquids of similar density have been added, its application scope is further broadened. Attached Figure Description

[0087] Figure 1 This is a schematic diagram of the method flow for a specific implementation of the present invention. Detailed Implementation

[0088] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0089] It should be noted beforehand that the principle of this invention is as follows:

[0090] After each urea injection, the linear relationship between the urea injection volume correction coefficient and the urea concentration is used to determine the validity of the urea quality sensor reading. If valid, the sensor reading is recorded as the urea concentration for this tank. Otherwise, the urea concentration is calculated by comparing the change in the urea injection coefficient after two consecutive injections with the urea concentration recorded after the previous injection. A low urea concentration fault is identified when the recorded urea concentration is less than CDmin.

[0091] Ideally, after each urea refill, the vehicle runs for a period of time, and the urea injection correction coefficient exhibits a negative linear relationship with the urea concentration. For example, when the urea concentration decreases by 10%, the urea injection correction coefficient will gradually stabilize at an increase of 10%. By observing the changes in the urea injection correction coefficient after two consecutive urea refills and the concentration of the previous tank of urea, the concentration of the current tank of urea can be accurately estimated. However, considering that in actual use, the urea injection correction coefficient is also affected by SCR urea crystallization, SCR sulfur poisoning, and inaccurate injection due to urea pump problems, the SCR efficiency may gradually deviate from its normal efficiency, thus affecting the urea injection correction coefficient. Consequently, the linear relationship between its change and the change in urea concentration may fluctuate slightly, resulting in an approximate linear correlation.

[0092] Normally, SCR urea crystallization and SCR sulfur poisoning are slow, gradual processes, and their impact on the urea injection quantity correction coefficient is much slower than the change in the urea injection quantity correction coefficient caused by changes in urea concentration. High / low urea consumption faults are generally caused by problems with the urea pump or nozzle; once this occurs, the fault will be reported quickly and easily resolved. Therefore, the approximate linear relationship between the urea injection quantity correction coefficient and urea concentration can be used to determine whether the urea quality sensor reading is usable and to calculate the urea concentration value after this urea injection. By appropriately selecting the urea quality sensor reading and calculated value, the accuracy of urea concentration calculation can be effectively improved. Using this accurate concentration value to diagnose the quality of the injected urea can effectively avoid false alarms caused by air bubbles, urea crystallization, etc., affecting the sensor reading; it can also accurately identify situations where the urea quality sensor cannot recognize liquids with densities similar to the standard urea solution; furthermore, this solution does not interfere with the vehicle's inherent urea injection logic and will not cause additional emission exceedances. This invention helps reduce false alarms of vehicle malfunctions, improve the user's driving experience and transportation efficiency.

[0093] A vehicle urea concentration detection system includes a data acquisition unit, a urea concentration calculation unit, and a data storage unit; wherein:

[0094] The data acquisition unit is used to collect raw data; the raw data includes the urea injection volume correction coefficient, the urea quality sensor reading, and the urea concentration value.

[0095] The urea concentration calculation unit is used to calculate the urea concentration value after this urea injection based on the raw data collected by the data acquisition unit.

[0096] The data storage unit is used to store the urea injection volume correction coefficient and urea concentration value after this urea injection.

[0097] In this specific embodiment, the urea injection volume correction coefficient includes the urea injection volume correction coefficient after this urea injection and the urea injection volume correction coefficient stored after the last urea injection; wherein:

[0098] The urea injection volume correction coefficient stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read.

[0099] Once the correction coefficient for the urea injection volume after the current urea injection is collected and used by the urea concentration calculation unit, the correction coefficient for the current urea injection volume after the current urea injection is written into the data storage unit, overwriting the correction coefficient for the urea injection volume stored after the previous urea injection.

[0100] In this specific embodiment, the urea concentration value includes the urea concentration value after this urea injection and the urea concentration value stored after the last urea injection; wherein:

[0101] The urea concentration value stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read.

[0102] Once the urea concentration value after the current urea injection is collected and used by the urea concentration calculation unit, the urea concentration value after the current urea injection is written into the data storage unit, overwriting the urea concentration value stored after the previous urea injection.

[0103] like Figure 1 As shown, a method for detecting the concentration of automotive urea using an automotive urea concentration detection system includes the following steps:

[0104] S100. Monitor in real time whether the vehicle is adding urea; then, based on the monitoring results, perform the following operations:

[0105] If the vehicle has not been refilled with urea, return and execute S100 again from the beginning.

[0106] If the vehicle is being refilled with urea for the first time, start the timer to begin accumulating the vehicle's running time; then execute S200.

[0107] S200. Compare the accumulated vehicle running time with a manually preset first time threshold; then perform the following operations based on the comparison result:

[0108] If the vehicle running time is less than the first time threshold, return and execute S200 again.

[0109] If the vehicle running time is not less than the first time threshold, the urea injection quantity correction coefficient and the urea quality sensor reading at the current moment are collected; then S300 is executed.

[0110] In this specific embodiment, the value range of the first time threshold is 1 hour to 3 hours.

[0111] S300. Calculate the ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution.

[0112] In this specific embodiment, the ratio of the reading measured by the urea mass sensor in S300 to the concentration of the standard automotive urea solution is expressed by formula (1):

[0113] B1=ω1 / 32.5% (1)

[0114] Where: B1 is the ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution; ω1 is the reading measured by the urea mass sensor.

[0115] S400. Determine whether the current urea mass sensor reading is valid; then, based on the determination result, perform the following operations:

[0116] If the result indicates that the reading of the urea mass sensor is valid, then the current urea concentration value is assigned to the current urea mass sensor reading; then S500 is executed.

[0117] If the result indicates that the reading of the urea mass sensor is invalid, then the calculated urea concentration value is assigned to the current urea concentration value; then S500 is executed.

[0118] In this specific embodiment, the calculated urea concentration is expressed according to formula (2):

[0119] ω c =32.5% / A1 (2)

[0120] Where: ω c This is the calculated value for urea concentration.

[0121] In this specific embodiment, determining whether the current urea quality sensor reading is valid in step S400 includes the following steps:

[0122] S410. Calculate the first reference value, expressed according to formula (3):

[0123] C1=|A1 / B1-1| (3)

[0124] Where: C1 is the first reference value; A1 is the correction coefficient for the urea injection volume collected in S200 at the current moment.

[0125] S420. Compare the first reference value with a manually preset first reference value threshold; then perform the following operations based on the comparison result:

[0126] If the first reference value is less than the first reference value threshold, the reading of the urea mass sensor is deemed valid.

[0127] If the first reference value is not less than the first reference value threshold, the reading of the urea quality sensor is determined to be invalid.

[0128] In this specific embodiment, the value range of the first reference value threshold is 3% to 5%.

[0129] S500. Store the urea injection volume correction coefficient collected in S200 at the current moment into the data storage unit as the urea injection volume correction coefficient after the last urea injection.

[0130] The current urea concentration value obtained by S400 is stored in the data storage unit as the urea concentration value after the last urea injection; then S600 is executed.

[0131] S600. Monitor the vehicle again in real time to see if urea is being added; then, based on the monitoring results, perform the following operations:

[0132] If the vehicle has not been refilled with urea, return and execute S600 from the beginning again.

[0133] If the vehicle is refilled with urea, the timer will restart to begin accumulating vehicle running time again; then S700 will be executed.

[0134] S700. Compare the accumulated vehicle running time with a manually preset second time threshold; then perform the following operations based on the comparison result:

[0135] If the vehicle running time is less than the second time threshold, return and execute S700 again.

[0136] If the vehicle running time is not less than the second time threshold, the urea injection quantity correction coefficient and the urea quality sensor reading at the current moment are collected; then the urea injection quantity correction coefficient and the urea concentration value after the last urea injection are read from the data storage unit; then S800 is executed.

[0137] In this specific embodiment, the value range of the second time threshold is 1 hour to 3 hours.

[0138] S800. Calculate the ratio of the reading measured by the urea mass sensor to the urea concentration value after the last urea addition in the data storage unit; then execute S900.

[0139] In this specific embodiment, the ratio of the reading measured by the urea mass sensor in S800 to the urea concentration value after the last urea addition in the data storage unit is expressed by equation (4):

[0140] B2=ω2 / ω (4)

[0141] Where: B2 is the ratio of the reading measured by the urea quality sensor to the urea concentration value after the last urea injection in the data storage unit; ω2 is the reading of the urea quality sensor in S700; ω is the urea concentration value after the last urea injection read from the data storage unit in S700.

[0142] S900. Determine whether the current urea mass sensor reading is valid; then, based on the determination result, perform the following operations:

[0143] If the result indicates that the reading of the urea mass sensor is valid, then the current urea concentration value is assigned to the current urea mass sensor reading; then S1000 is executed.

[0144] If the judgment result is that the reading of the urea quality sensor is invalid, the current urea concentration value is calculated based on the relationship between the change ratio of the urea injection volume correction coefficient obtained after the last two urea injections and the urea concentration value; then S1000 is executed.

[0145] In this specific embodiment, determining whether the current urea quality sensor reading is valid in step S900 includes the following steps:

[0146] S910. Calculate the second reference value, expressed as in equation (5):

[0147] C2=|A2 / (A*B2)-1|(5)

[0148] Where: C2 is the second reference value; A2 is the correction coefficient for the urea injection volume at the current moment collected in S700; A is the correction coefficient for the urea injection volume after the last urea injection read from the data storage unit in S700.

[0149] S920. Compare the second reference value with a manually preset second reference value threshold; then perform the following operations based on the comparison result:

[0150] If the second reference value is less than the second reference value threshold, the reading of the urea mass sensor is deemed valid.

[0151] If the second reference value is not less than the second reference value threshold, the reading of the urea mass sensor is deemed invalid.

[0152] In this specific embodiment, the value range of the first reference value threshold is 3% to 5%.

[0153] In S900, the current urea concentration is calculated based on the relationship between the ratio of the change ratio of the urea injection volume correction coefficient obtained after the two most recent urea injections and the ratio of the urea concentration value, and is expressed by equation (6):

[0154] ω'=ω*A / A2 (6)

[0155] Where: ω' is the urea concentration value for this time.

[0156] S1000. Store the urea injection volume correction coefficient collected in S700 at the current moment into the data storage unit as the urea injection volume correction coefficient after the last urea injection.

[0157] The current urea concentration value obtained by S900 is stored in the data storage unit as the urea concentration value after the last urea injection; then S1100 is executed.

[0158] S1100. Iterate through S600 to S1000 until the urea injection quantity correction coefficient is no longer within the range of the manually preset urea injection quantity correction coefficient, or a low SCR efficiency fault occurs, or a high urea consumption fault occurs, or a low urea consumption fault occurs, then execute S1200.

[0159] It should be noted that during the iterative execution of S600 to S1000, in particular, considering the interference of factors such as SCR crystallization, sulfur poisoning, and urea pump problems causing high / low urea injection volume faults, the ratio of change in the urea injection volume correction coefficient to the urea concentration may gradually deviate from a linear correlation. Therefore, when a fault occurs where the urea injection correction exceeds the range (urea injection volume correction coefficient exceeds the upper limit or falls below the lower limit), or a fault occurs where the SCR efficiency is low, or a fault occurs where urea consumption is high / low, the calculated urea concentration is considered invalid. At this time, the stored urea concentration ω is reset to 32.5% and locked, and the stored urea injection volume correction coefficient A is reset to 1 and locked. This process continues until the faults such as urea injection correction exceeding the range, low SCR efficiency, high urea consumption, and low urea consumption disappear. Then, the next urea injection is identified, and the process is restarted from S100. This is the basis for the execution of S1200 to S1300.

[0160] S1200. Reset the urea concentration value stored in the data storage unit to 32.5% and lock it; reset the urea injection quantity correction coefficient stored in the data storage unit to 1 and lock it; then execute S1300.

[0161] S1300. Check if the urea injection quantity correction factor has returned to the range of the urea injection quantity correction factor, and if the low SCR efficiency fault, high urea consumption fault, and low urea consumption fault have all disappeared; then, based on the check results, perform the following operations:

[0162] If the urea injection quantity correction coefficient returns to the range of the urea injection quantity correction coefficient, and the low SCR efficiency fault disappears, and the high urea consumption fault disappears, and the low urea consumption fault disappears, then return to and re-execute S100.

[0163] If the urea injection quantity correction factor does not return to the range of the urea injection quantity correction factor, or the low SCR efficiency fault does not disappear, or the high urea consumption fault does not disappear, or the low urea consumption fault does not disappear, then return to and re-execute S1300.

[0164] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0165] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0166] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0167] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting the concentration of automotive urea, characterized in that: Includes the following steps: S50. Perform the initial urea concentration detection procedure, which includes the following steps: S100. Real-time monitoring of whether the vehicle is adding urea; S200. Compare the accumulated vehicle running time with the manually preset first time threshold; collect the urea injection quantity correction coefficient at the current moment and the reading of the urea quality sensor at the current moment; S300. Calculate the ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution; S400. Determine whether the reading of the urea mass sensor is valid; obtain the current urea concentration value. S500. Store the urea injection volume correction coefficient collected in S200 at the current moment into the data storage unit, as the urea injection volume correction coefficient after the last urea injection. The current urea concentration value obtained by S400 is stored in the data storage unit as the urea concentration value after the last urea injection; then S600 is executed. S600. Monitor the vehicle again in real time to see if urea is being added; then, based on the monitoring results, perform the following actions: If the vehicle has not been refilled with urea, return and execute S600 from the beginning again; If the vehicle is refilled with urea, the timer is restarted to begin accumulating the vehicle's running time again; then S700 is executed. S700. Compare the accumulated vehicle running time with a manually preset second time threshold; then perform the following operations based on the comparison result: If the vehicle running time is less than the second time threshold, return and execute S700 again; If the vehicle running time is not less than the second time threshold, then the urea injection quantity correction coefficient at the current moment and the reading of the urea quality sensor at the current moment are collected. Then, the urea injection volume correction coefficient and the urea concentration value after the last urea injection are read from the data storage unit; then, S800 is executed. S800. Calculate the ratio of the reading measured by the urea mass sensor to the urea concentration value after the last urea injection in the data storage unit; then execute S900; S900. Determine whether the reading of the urea mass sensor is valid; then, based on the determination result, perform the following operations: If the determination result is that the reading of the urea mass sensor is valid, then the reading of the urea mass sensor is assigned to the current urea concentration value; then S1000 is executed; If the determination result is that the reading of the urea quality sensor is invalid, the current urea concentration value is calculated based on the relationship between the change ratio of the urea injection volume correction coefficient obtained after the last two urea injections and the ratio of the urea concentration value. Then execute S1000; S1000. Store the urea injection volume correction coefficient collected in S700 at the current moment into the data storage unit, as the urea injection volume correction coefficient after the last urea injection. The current urea concentration value obtained by S900 is stored in the data storage unit as the urea concentration value after the last urea injection; then S1100 is executed. S1100. Iteratively execute S600 to S1000 until the urea injection quantity correction coefficient is no longer within the range of the manually preset urea injection quantity correction coefficient, or a low SCR efficiency fault occurs, or a high urea consumption fault occurs, or a low urea consumption fault occurs, then execute S1200. S1200. Reset the urea concentration value stored in the data storage unit to 32.5% and lock it; The urea injection quantity correction coefficient stored in the data storage unit is reset to 1 and locked; then S1300 is executed; S1300. Check whether the urea injection volume correction coefficient has returned to the range of the urea injection volume correction coefficient, and whether the low SCR efficiency fault has disappeared, the high urea consumption fault has disappeared, and the low urea consumption fault has disappeared; if the check result is that all the above conditions are met, then when the next urea injection is detected, S100 is executed again.

2. The method for detecting the concentration of automotive urea according to claim 1, characterized in that: In the initial urea concentration detection procedure described in S50: In S100, the following operations are then performed based on the monitoring results: If the vehicle has not been refilled with urea, return and execute S100 again from the beginning; If the vehicle is being refilled with urea for the first time, start the timer to begin accumulating the vehicle's running time; then execute S200. In S200, the following operations are then performed based on the comparison results: If the vehicle running time is less than the first time threshold, return and execute S200 again; If the vehicle running time is not less than the first time threshold, then collect the urea injection quantity correction coefficient at the current moment and the reading of the urea quality sensor at the current moment; then execute S300. In S400, the following operation is then performed based on the judgment result: If the determination result is that the reading of the urea mass sensor is valid, then the reading of the urea mass sensor is assigned to the current urea concentration value; then S500 is executed; If the determination result is that the reading of the urea mass sensor is invalid, then the calculated urea concentration value is assigned to the current urea concentration value; then S500 is executed; In S1300, if the check result shows that all the above conditions are met, then when the next urea injection is detected, S100 is re-executed, which specifically includes the following steps: Based on the inspection results, the following actions were taken: If the urea injection quantity correction coefficient returns to the range of the urea injection quantity correction coefficient, and the low SCR efficiency fault disappears, and the high urea consumption fault disappears, and the low urea consumption fault disappears, then return to and re-execute S100. If the urea injection quantity correction coefficient does not return to the range of the urea injection quantity correction coefficient, or the low SCR efficiency fault does not disappear, or the high urea consumption fault does not disappear, or the low urea consumption fault does not disappear, then return to and re-execute S1300. The first time threshold ranges from 1 hour to 3 hours.

3. The method for detecting the concentration of automotive urea according to claim 2, characterized in that: The ratio of the reading measured by the urea mass sensor in S300 to the concentration of the standard automotive urea solution is expressed by the following formula: in: The ratio of the reading measured by the urea mass sensor to the concentration of the standard automotive urea solution; The readings measured by the urea mass sensor.

4. The method for detecting the concentration of automotive urea according to claim 3, characterized in that: S400 determines whether the reading of the urea quality sensor is valid, specifically including the following steps: S410. Calculate the first reference value, expressed as follows: in: The first reference value; The correction coefficient for the urea injection volume collected in S200 at the current moment; S420. Compare the first reference value with a manually preset first reference value threshold; then perform the following operations based on the comparison result: If the first reference value is less than the first reference value threshold, the reading of the urea quality sensor is determined to be valid. If the first reference value is not less than the first reference value threshold, then the reading of the urea quality sensor is determined to be invalid.

5. The method for detecting the concentration of automotive urea according to claim 4, characterized in that: The calculated urea concentration is expressed by the following formula: in: This is the calculated value of the urea concentration.

6. The method for detecting the concentration of automotive urea according to claim 5, characterized in that: The ratio of the reading measured by the urea mass sensor in S800 to the urea concentration value in the data storage unit after the last urea addition is expressed by the following formula: in: The ratio of the reading measured by the urea quality sensor to the urea concentration value after the last urea addition in the data storage unit; The reading of the urea mass sensor described in S700; The urea concentration value read from the data storage unit in S700 after the last urea injection.

7. The method for detecting the concentration of automotive urea according to claim 6, characterized in that: The S900 process determines whether the reading from the urea quality sensor is valid by including the following steps: S910. Calculate the second reference value, expressed as follows: in: This is the second reference value; The correction coefficient for the urea injection volume collected in S700 at the current moment; The correction factor for the urea injection volume after the last urea injection, read from the data storage unit in S700; S920. Compare the second reference value with a manually preset second reference value threshold; then perform the following operations based on the comparison result: If the second reference value is less than the second reference value threshold, the reading of the urea mass sensor is determined to be valid. If the second reference value is not less than the second reference value threshold, the reading of the urea mass sensor is determined to be invalid. In S900, the current urea concentration is calculated based on the relationship between the ratio of the change ratio of the urea injection volume correction coefficient obtained after the two most recent urea injections and the ratio of the urea concentration value, expressed by the following formula: in: This refers to the urea concentration value mentioned in this study.

8. A vehicle urea concentration detection system utilizing the vehicle urea concentration detection method of claim 7, characterized in that: It includes a data acquisition unit, a urea concentration calculation unit, and a data storage unit; wherein: The data acquisition unit is used to acquire raw data; the raw data includes urea injection volume correction coefficient, urea mass sensor reading, and urea concentration value. The urea concentration calculation unit is used to calculate the urea concentration value after this urea injection based on the raw data collected by the data acquisition unit. The data storage unit is used to store the urea injection volume correction coefficient and the urea concentration value after this urea injection.

9. The vehicle urea concentration detection system according to claim 8, characterized in that: The urea injection volume correction coefficient includes the urea injection volume correction coefficient after this urea injection and the urea injection volume correction coefficient stored after the last urea injection; wherein: The urea injection volume correction coefficient stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read; Once the correction coefficient for the urea injection volume after the current urea injection is collected and used by the urea concentration calculation unit, the correction coefficient for the current urea injection volume after the current urea injection is written into the data storage unit, overwriting the correction coefficient for the urea injection volume stored after the previous urea injection.

10. The vehicle urea concentration detection system according to claim 9, characterized in that: The urea concentration value includes the urea concentration value after this urea injection and the urea concentration value stored after the last urea injection; wherein: The urea concentration value stored after the last urea injection is stored in the data storage unit for the data acquisition unit to read; Once the urea concentration value after the current urea injection is collected and used by the urea concentration calculation unit, the urea concentration value after the current urea injection is written into the data storage unit, overwriting the urea concentration value stored after the previous urea injection.

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