Urea injection control method and device

Abstract

The present application provides a urea injection control method and device, the method comprising: obtaining a sensor signal collected by a nitrogen oxide sensor of a vehicle; if the sensor signal meets a strong transient condition, obtaining a feedforward ammonia nitrogen ratio base value and a control parameter base value of a closed-loop control system of the SCR according to the temperature and airspeed of the selective catalytic reduction SCR system of the vehicle; correcting the control parameter base value according to the temperature of the SCR system and the ammonia reserve to obtain a target control parameter; correcting the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient intensity of the sensor signal to obtain a target feedforward ammonia nitrogen ratio; obtaining a required ammonia nitrogen ratio based on ammonia reserves, ammonia reserves set value, a closed-loop control system, a target control parameter and a target feedforward ammonia nitrogen ratio; and controlling urea injection according to the required ammonia nitrogen ratio. The method provided by the present application can meet the emission requirements of a vehicle when it is running under high-efficiency conditions.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a urea injection control method and device. Background Art

[0002] In modern internal combustion engine technology, especially for diesel engines using selective catalytic reduction (SCR) technology, bench calibration is a key step to ensure that engine emission performance meets strict environmental regulations. The SCR system converts nitrogen oxides (NOx) into harmless nitrogen and water under the action of a catalyst by injecting urea aqueous solution into the exhaust. In order to achieve efficient and precise control of this conversion process, it is necessary to accurately calibrate multiple parameters of the SCR system, including feedforward control parameters and ammonia storage closed-loop control parameters.

[0003] Traditionally, the calibration of these parameters is usually carried out on the engine bench and is based on the operating data of the engine under normal efficiency conditions. During this calibration process, the urea injection amount, injection timing and other parameters are adjusted to ensure that when the engine is running within the normal efficiency range, its emission level can stably meet the established standards.

[0004] However, when the vehicle is running at maximum efficiency on actual roads or under specific operating conditions, the engine load, speed and emission characteristics will change significantly, resulting in the parameters previously calibrated based on normal efficiency conditions no longer being applicable. Specifically, when the engine is operating at maximum efficiency, its exhaust temperature, flow rate and NOx emission concentration may all increase significantly, which places higher demands on the urea injection strategy of the SCR system. If the calibration data based on normal efficiency conditions is still used to control urea injection, it is likely that the urea injection amount will be insufficient or the injection timing will be inappropriate, and the NOx in the exhaust will not be effectively neutralized, resulting in excessive tail gas emissions. Summary of the invention

[0005] The technical problem to be solved by the present application is to provide a urea injection control method that can meet the emission requirements of a vehicle when it is running under high-efficiency conditions.

[0006] The present application also provides a urea injection control device to ensure the implementation and application of the above method in practice.

[0007] A urea injection control method, the method comprising:

[0008] Obtaining a sensor signal collected by a nitrogen oxide sensor of the vehicle within a current time period;

[0009] When it is detected that the sensor signal collected in the current time period meets the preset strong transient condition, a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of the closed-loop control system of the SCR are obtained according to the temperature and airspeed of the SCR system of the vehicle;

[0010] Correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter;

[0011] Correcting the feedforward ammonia-nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia-nitrogen ratio;

[0012] Obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve set value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio;

[0013] The urea injection is controlled according to the required ammonia-nitrogen ratio.

[0014] The above method may optionally include detecting that the sensor signal collected in the current time period meets a preset strong transient condition, including:

[0015] Performing integration processing on the sensor signal collected in the current time period to obtain an integral value corresponding to the sensor signal;

[0016] Determining the transient strength of the sensor signal according to the integral value corresponding to the sensor signal and a preset standard integral value;

[0017] When the transient intensity of the sensor signal is greater than a preset transient intensity threshold, it is determined that the sensor signal meets a preset strong transient condition.

[0018] In the above method, optionally, the control parameter base value is corrected according to the temperature and ammonia reserve of the SCR system to obtain the target control parameter, including:

[0019] Determining a difference value between an ammonia reserve of the SCR system and a preset ammonia reserve setting value, wherein the difference value represents a degree of difference between the ammonia reserve and the ammonia reserve setting value;

[0020] According to the temperature of the SCR system and the difference value, a preset first configuration file is searched to obtain a correction amount of the basic value of the control parameter;

[0021] The control parameter basic value is corrected according to the correction amount of the control parameter basic value to obtain the target control parameter.

[0022] The above method, optionally, correcting the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain the target feedforward ammonia nitrogen ratio includes:

[0023] querying a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value;

[0024] The feedforward ammonia-nitrogen ratio basic value is corrected according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

[0025] The above method, optionally, obtaining the required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, the preset ammonia reserve set value, the closed-loop control system, the target control parameter and the target feedforward ammonia nitrogen ratio includes:

[0026] Updating control parameters of the closed-loop control system using the target control parameters;

[0027] The difference between the ammonia reserve and a preset ammonia reserve set value is input into the updated closed-loop control system to obtain a closed-loop ammonia nitrogen ratio;

[0028] The required ammonia nitrogen ratio of the SCR system is obtained according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

[0029] A urea injection control device, comprising:

[0030] An acquisition unit, used to acquire a sensor signal collected by a nitrogen oxide sensor of the vehicle within a current time period;

[0031] A first execution unit is used to obtain a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of a closed-loop control system of the SCR according to a temperature and an airspeed of the SCR system of the vehicle when it is detected that a sensor signal collected in a current time period meets a preset strong transient condition;

[0032] A first correction unit, configured to correct the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter;

[0033] a second correction unit, configured to correct the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio;

[0034] a second execution unit, configured to obtain a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve setting value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio;

[0035] A control unit is used to control urea injection according to the required ammonia-nitrogen ratio.

[0036] In the above device, optionally, the first execution unit includes:

[0037] The integration subunit is used to integrate the sensor signal collected in the current time period to obtain the integral value corresponding to the sensor signal;

[0038] A first determining subunit, configured to determine the transient strength of the sensor signal according to an integral value corresponding to the sensor signal and a preset standard integral value;

[0039] The second determining subunit is used to determine that the sensor signal meets a preset strong transient condition when the transient intensity of the sensor signal is greater than a preset transient intensity threshold.

[0040] In the above device, optionally, the first correction unit includes:

[0041] a third determination subunit, configured to determine a difference between the ammonia reserve of the SCR system and a preset ammonia reserve setting value, wherein the difference value represents a degree of difference between the ammonia reserve and the ammonia reserve setting value;

[0042] A first query subunit, configured to query a preset first configuration file according to the temperature of the SCR system and the difference value, to obtain a correction amount of the basic value of the control parameter;

[0043] The first correction subunit is used to correct the control parameter basic value according to the correction amount of the control parameter basic value to obtain the target control parameter.

[0044] In the above device, optionally, the second correction unit includes:

[0045] A second query subunit is used to query a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value;

[0046] The second correction subunit is used to correct the feedforward ammonia-nitrogen ratio basic value according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

[0047] The above device may optionally further include:

[0048] An updating subunit, used to update the control parameters of the closed-loop control system using the target control parameters;

[0049] a first execution subunit, for inputting a difference between the ammonia reserve and a preset ammonia reserve setting value into an updated closed-loop control system to obtain a closed-loop ammonia-nitrogen ratio;

[0050] The second execution subunit is used to obtain the required ammonia nitrogen ratio of the SCR system according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

[0051] Compared with the prior art, this application has the following advantages:

[0052] The present application provides a method and device for determining an exhaust gas aftertreatment system, the method comprising: obtaining a sensor signal collected by a nitrogen oxide sensor of a vehicle in a current time period; obtaining a feedforward ammonia nitrogen ratio base value and a control parameter base value of a selective catalytic reduction SCR system of the vehicle according to the temperature and airspeed of the SCR system when the sensor signal collected in the current time period meets a preset strong transient condition; correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter; correcting the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio; obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve setting value, the closed-loop control system, the target control parameter and the target feedforward ammonia nitrogen ratio; and controlling urea injection according to the required ammonia nitrogen ratio. The emission requirements of the vehicle when operating under high-efficiency conditions can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0054] Figure 1 A flow chart of a urea injection control method provided in this application;

[0055] Figure 2 A flowchart of a process for detecting that a sensor signal collected in the current time period meets a strong transient condition provided by the present application;

[0056] Figure 3 A flowchart of a process for obtaining target control parameters provided by the present application;

[0057] Figure 4 An example diagram of a sensor signal provided for this application;

[0058] Figure 5 A schematic diagram of the structure of a urea injection control device provided in this application;

[0059] Figure 6 A schematic diagram of the structure of an electronic device provided in this application. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0062] Based on this, the embodiment of the present application provides a urea injection control method, which can be applied to electronic equipment, and the electronic equipment may include a transmission control unit TCU, an ECU (Electronic Control Unit), a VCU (Vehicle Control Unit), an MCU (Micro Controller Unit), an HCU (Hybrid Control Unit), a server, a PC, a PAD, a mobile phone, etc. One or more of the above; the method flow chart of the method is as follows Figure 1 As shown, specifically including:

[0063] S101: Acquire a sensor signal collected by a nitrogen oxide sensor of a vehicle in a current time period.

[0064] In this embodiment, the nitrogen oxide sensor may be a sensor in a post-treatment system of a vehicle engine, for detecting nitrogen oxides in exhaust gas discharged by the engine.

[0065] Optionally, the current time period may be a time period consisting of the current time point and a time point before the current time point, and the length of the time period may be 30s, 60s, etc., and this embodiment does not limit the length of the time period. In some embodiments, the current time period may be a current cycle.

[0066] S102: When it is detected that the sensor signal collected in the current time period meets the preset strong transient condition, a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of the SCR closed-loop control system are obtained according to the temperature and airspeed of the SCR system.

[0067] In this embodiment, the strong transient condition may be that the amplitude of the sensor signal collected in the current time period (unit time) is greater than the preset amplitude threshold, and the frequency of change is greater than the preset frequency threshold; the frequency of change may refer to the number of times the sensor signal fluctuates up and down. The strong transient condition may also be that the transient intensity of the sensor signal is greater than the preset transient intensity threshold.

[0068] Optionally, a preset first relationship table may be queried through the temperature and air speed of the SCR system to obtain a basic value of the feedforward ammonia nitrogen ratio of the SCR closed-loop control system.

[0069] Optionally, a preset second relationship table may be queried through the temperature and airspeed of the SCR system to obtain a basic value of a control parameter of a closed-loop control system of the SCR.

[0070] In this embodiment, the closed-loop control system may be a PID control system, and the control parameter basic value may include a PID control parameter, such as a proportional coefficient basic value and an integral coefficient basic value.

[0071] S103: Correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter.

[0072] In this embodiment, the target control parameters may include a target proportional coefficient Kp and a target integral coefficient ki in a closed-loop control system.

[0073] S104: Correcting the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio.

[0074] In this embodiment, the correction value of the feedforward ammonia-nitrogen ratio base value can be determined according to the temperature of the SCR system and the transient intensity of the sensor signal, and then the feedforward ammonia-nitrogen ratio base value is corrected according to the correction value of the feedforward nitrogen-ammonia ratio base value to obtain the target feedforward ammonia-nitrogen ratio.

[0075] S105: Obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve set value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio.

[0076] In this embodiment, the closed-loop control system can be updated using the target control parameters, and then the closed-loop ammonia nitrogen ratio is obtained based on the ammonia storage difference through the updated closed-loop control system; and the required ammonia nitrogen ratio of the SCR system is obtained based on the closed-loop ammonia nitrogen ratio and the target feedforward ammonia nitrogen ratio.

[0077] S106: Controlling urea injection according to the required ammonia-nitrogen ratio.

[0078] In this embodiment, the required urea mass flow rate can be calculated according to the required ammonia nitrogen ratio and the mass flow rate of nitrogen oxides upstream of the SCR, and then the actuator controls the actual urea injection amount based on the required urea mass flow rate.

[0079] In this embodiment, the injection level and injection state of the SCR urea can be adjusted according to the transient intensity of the vehicle operation, so as to meet the emission requirements when the vehicle is running under high-efficiency conditions.

[0080] In an embodiment provided in the present application, based on the above solution, optionally, a process in which the sensor signal collected in the current time period meets a preset strong transient condition is detected, such as Figure 2 As shown, including:

[0081] S201: performing integration processing on the sensor signal collected in the current time period to obtain an integration value corresponding to the sensor signal.

[0082] In this embodiment, the sensor signal may be derived in real time and its absolute value may be taken to obtain the absolute value of the derivative of the sensor signal, and then the absolute value of the derivative may be integrated to obtain the integral value corresponding to the sensor.

[0083] S202: Determine the transient strength of the sensor signal according to the integral value corresponding to the sensor signal and a preset standard integral value.

[0084] In this embodiment, the integral value corresponding to the sensor signal may be divided by the standard integral value to obtain the transient strength of the sensor signal.

[0085] S203: When the transient intensity of the sensor signal is greater than a preset transient intensity threshold, determine that the sensor signal meets a preset strong transient condition.

[0086] In this embodiment, when the transient intensity of the sensor signal is not greater than the transient intensity threshold, it is determined that the sensor signal does not meet the strong transient condition.

[0087] In an embodiment provided in the present application, based on the above solution, optionally, the process of correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain the target control parameter is as follows: Figure 3 As shown, including:

[0088] S301: Determine a difference value between an ammonia storage amount of an SCR system and a preset ammonia storage amount setting value, wherein the difference value represents a degree of difference between the ammonia storage amount and the ammonia storage amount setting value.

[0089] In this embodiment, the difference between the ammonia reserve and the ammonia reserve setting value may be the difference between the ammonia reserve and the ammonia reserve setting value, or the ammonia reserve difference percentage; the ammonia reserve difference percentage is obtained by multiplying the ammonia reserve difference by 100%.

[0090] S302: querying a preset first configuration file according to the temperature of the SCR system and the difference value to obtain a correction amount of the basic value of the control parameter.

[0091] In this embodiment, the first configuration file may be a relationship comparison table recording the corresponding relationship between the temperature of the SCR system, the difference value and the correction amount based on the control parameter, or a function curve, etc.

[0092] S303: Correct the control parameter basic value according to the correction amount of the control parameter basic value to obtain a target control parameter.

[0093] In this embodiment, the correction amount of the control parameter base value may include at least one of an integral coefficient correction amount, a proportional coefficient correction amount and a differential coefficient correction amount.

[0094] Optionally, the target integral coefficient is obtained by adding the integral coefficient base value and the integral coefficient correction amount in the control parameter base value; and the target proportional coefficient is obtained by adding the proportional coefficient base value and the proportional coefficient correction amount.

[0095] In an embodiment provided in the present application, based on the above solution, optionally, the feedforward ammonia nitrogen ratio base value is corrected according to the temperature of the SCR system and the transient strength of the sensor signal to obtain the target feedforward ammonia nitrogen ratio, including:

[0096] querying a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value;

[0097] The feedforward ammonia-nitrogen ratio basic value is corrected according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

[0098] In this embodiment, the second configuration file may be a relationship comparison table recording the corresponding relationship between the temperature of the SCR system, the transient intensity and the correction amount of the feedforward ammonia nitrogen ratio basic value, or a function curve, etc.

[0099] Optionally, the feedforward ammonia-nitrogen ratio base value and the correction amount of the feedforward ammonia-nitrogen ratio base value may be added to obtain the target feedforward ammonia-nitrogen ratio.

[0100] In an embodiment provided in the present application, based on the above solution, optionally, obtaining the required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, the preset ammonia reserve setting value, the closed-loop control system, the target control parameter and the target feedforward ammonia nitrogen ratio includes:

[0101] Updating control parameters of the closed-loop control system using the target control parameters;

[0102] The difference between the ammonia reserve and a preset ammonia reserve set value is input into the updated closed-loop control system to obtain a closed-loop ammonia nitrogen ratio;

[0103] The required ammonia nitrogen ratio of the SCR system is obtained according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

[0104] In this embodiment, the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio may be summed to obtain the required ammonia nitrogen ratio of the SCR system.

[0105] In an embodiment provided in the present application, based on the above solution, optionally, it further includes:

[0106] When it is detected that the sensor signal collected in the current time period does not meet the preset strong transient condition, a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of the closed-loop control system of the SCR are obtained according to the temperature and airspeed of the SCR system of the vehicle;

[0107] Obtaining a required ammonia nitrogen ratio of the SCR system based on the closed-loop control system, the control parameter basic value, and the feedforward ammonia nitrogen ratio basic value;

[0108] The urea injection is controlled according to the required ammonia-nitrogen ratio.

[0109] In this embodiment, the closed-loop control system can be updated using the control parameter base value, and then the updated closed-loop control system is used to output a closed-loop ammonia nitrogen ratio based on the difference between the ammonia reserve and the preset ammonia reserve set value. The feedforward ammonia nitrogen ratio base value is then summed with the closed-loop ammonia nitrogen ratio to obtain the required ammonia nitrogen ratio, and finally the urea injection is controlled according to the required ammonia nitrogen ratio.

[0110] In one embodiment provided by the present application, the strong transient state recognition can be performed on the signal of the NOx sensor upstream of the SCR system. The strength of the transient signal is determined based on the change amplitude and change frequency of the signal itself, such as Figure 4 As shown, the strong transient signal has a large change amplitude and a high frequency (frequency refers to the number of up and down fluctuations per unit time). If these two conditions are met, it is a strong transient signal, otherwise it is a weak transient signal. The change slope of the strong transient signal is relatively large and the change frequency per unit time is relatively high. Therefore, the signal is derived, and the absolute value is taken and integrated per unit time. Obviously, the integral value of the strong transient signal is much larger than the integral value of the weak transient signal. Therefore, this embodiment can use the size of the integral value to identify the strength of the transient state. The identification steps are as follows:

[0111] The NOx sensor signal is derived in real time and its absolute value is taken, and the absolute value of the derivative is integrated (the integration time is 30 seconds) to obtain the current integral value;

[0112] The current integrated value divided by the integrated value of normal efficiency gives the transient intensity;

[0113] The magnitude of the transient intensity and the transient intensity threshold is judged. When the transient intensity is greater than the preset transient intensity threshold, it is determined that the upstream NOx sensor signal is in a strong transient state (i.e., the strong transient condition is met); otherwise, it is considered that the upstream NOx sensor signal is in a non-strong transient state (i.e., the strong transient condition is not met).

[0114] Based on the strong transient state, the SCR urea injection process is adaptively controlled. The control process is as follows:

[0115] Based on the current SCR temperature and airspeed, search the feedforward ammonia nitrogen ratio setting map to obtain the feedforward ammonia nitrogen ratio basic value;

[0116] Based on the current SCR temperature and air speed, respectively search for the ammonia storage closed loop Kp parameter setting map and the ammonia storage closed loop Ki parameter setting map to obtain the Kp parameter basic value and the Ki parameter basic value;

[0117] Subtract the actual ammonia storage from the set ammonia storage, divide it by the set ammonia storage, and multiply it by 100% to get the ammonia storage difference percentage. Based on the current SCR temperature and the ammonia storage difference percentage, look up the Kp correction map and the Ki correction map to get the Kp correction value and the Ki correction value.

[0118] Based on the current SCR temperature and transient intensity, the feedforward ammonia nitrogen ratio correction map is searched to obtain the feedforward ammonia nitrogen ratio correction value.

[0119] When the signal of the upstream NOx sensor does not meet the strong transient condition, the basic value of the feedforward ammonia nitrogen ratio of the closed-loop control system is determined as the feedforward opening setting value, the ammonia storage closed-loop Kp parameter in the closed-loop control system takes the Kp parameter basic value, and the ammonia storage closed-loop Ki parameter takes the Ki parameter basic value. PID control is performed based on the ammonia storage difference to obtain the closed-loop ammonia nitrogen ratio, and the feedforward opening setting value + closed-loop ammonia nitrogen ratio obtains the required ammonia nitrogen ratio. The SCR urea injection finally injects urea according to the output required ammonia nitrogen ratio.

[0120] When the signal of the upstream NOx sensor meets the strong transient condition, the basic value of the feedforward ammonia nitrogen ratio is added to the correction value of the feedforward ammonia nitrogen ratio to obtain the feedforward opening setting value. The ammonia storage closed-loop Kp parameter (target proportional coefficient) takes the sum of the Kp parameter basic value and the Kp correction value, and the ammonia storage closed-loop Ki parameter (target integral coefficient) takes the Ki parameter basic value + Ki correction value. Based on the ammonia storage difference, PID control is performed to obtain the closed-loop ammonia nitrogen ratio. The feedforward opening setting value plus the closed-loop ammonia nitrogen ratio obtain the required ammonia nitrogen ratio. The SCR urea injection finally injects urea according to the output required ammonia nitrogen ratio.

[0121] In this embodiment, when the vehicle is working at maximum efficiency, the transient intensity of upstream NOx is relatively strong, and a relatively stable urea injection state with a relatively large ammonia nitrogen ratio is required to reduce the tail NOx level to the range required by regulations. In the conventional control method, the calibration of the feedforward ammonia nitrogen ratio and the calibration level of the ammonia storage closed-loop parameter are calibrated when the loader is in a normal efficiency working state, which can only meet the emission level of normal efficiency. For the machine working at maximum efficiency, the urea injection amount is insufficient and cannot meet the emission of maximum efficiency. Therefore, in this solution, when it is detected that the vehicle is in a strong transient state, the correction function of the feedforward ammonia nitrogen ratio and the correction function of the ammonia storage closed-loop parameter are enabled, wherein the correction value of the feedforward ammonia nitrogen ratio is a value greater than 0, which mainly plays the role of adding injection, and the calibration value in the correction map of the ammonia storage closed-loop parameter is set to a relatively small value (ranging from 0 to 1), the purpose of which is to weaken the ammonia storage closed-loop effect as much as possible, so that the final required ammonia nitrogen ratio is continuously maintained at a relatively high level, thereby achieving the effect of reducing tail emissions.

[0122] By applying the control scheme provided in this embodiment, the injection level and injection state of the SCR urea can be adaptively adjusted according to the transient intensity of the vehicle operation, taking into account emissions under normal efficiency and maximum efficiency.

[0123] and Figure 1 Corresponding to the method described above, the embodiment of the present application further provides a urea injection control device for Figure 1 The specific implementation of the method is shown in the following diagram: Figure 5 As shown, specifically including:

[0124] An acquisition unit 501 is used to acquire a sensor signal collected by a nitrogen oxide sensor of a vehicle in a current time period;

[0125] The first execution unit 502 is used to obtain a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of a closed-loop control system of the SCR according to the temperature and airspeed of the SCR system of the vehicle when it is detected that the sensor signal collected in the current time period meets a preset strong transient condition;

[0126] A first correction unit 503, configured to correct the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter;

[0127] A second correction unit 504 is used to correct the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio;

[0128] A second execution unit 505 is used to obtain a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve setting value, the closed-loop control system, the target control parameter and the target feedforward ammonia nitrogen ratio;

[0129] The control unit 506 is used to control urea injection according to the required ammonia nitrogen ratio.

[0130] In an embodiment provided in the present application, based on the above implementation process, optionally, the first execution unit 502 includes:

[0131] The integration subunit is used to integrate the sensor signal collected in the current time period to obtain the integral value corresponding to the sensor signal;

[0132] A first determining subunit, configured to determine the transient strength of the sensor signal according to an integral value corresponding to the sensor signal and a preset standard integral value;

[0133] The second determining subunit is used to determine that the sensor signal meets a preset strong transient condition when the transient intensity of the sensor signal is greater than a preset transient intensity threshold.

[0134] In an embodiment provided in the present application, based on the above implementation process, optionally, the first correction unit 503 includes:

[0135] a third determination subunit, configured to determine a difference between the ammonia reserve of the SCR system and a preset ammonia reserve setting value, wherein the difference value represents a degree of difference between the ammonia reserve and the ammonia reserve setting value;

[0136] A first query subunit, configured to query a preset first configuration file according to the temperature of the SCR system and the difference value, to obtain a correction amount of the basic value of the control parameter;

[0137] The first correction subunit is used to correct the control parameter basic value according to the correction amount of the control parameter basic value to obtain the target control parameter.

[0138] In an embodiment provided in the present application, based on the above implementation process, optionally, the second correction unit 504 includes:

[0139] A second query subunit is used to query a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value;

[0140] The second correction subunit is used to correct the feedforward ammonia-nitrogen ratio basic value according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

[0141] In an embodiment provided in the present application, based on the above implementation process, optionally, the second execution unit 505 includes:

[0142] An updating subunit, used to update the control parameters of the closed-loop control system using the target control parameters;

[0143] a first execution subunit, for inputting a difference between the ammonia reserve and a preset ammonia reserve setting value into an updated closed-loop control system to obtain a closed-loop ammonia-nitrogen ratio;

[0144] The second execution subunit is used to obtain the required ammonia nitrogen ratio of the SCR system according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

[0145] The specific principles and execution processes of each unit and module in the urea injection control device disclosed in the above embodiment of the present application are the same as those of the urea injection control method disclosed in the above embodiment of the present application. Please refer to the corresponding parts of the urea injection control method provided in the above embodiment of the present application, and no further details will be given here.

[0146] An embodiment of the present application further provides a storage medium, wherein the storage medium includes stored instructions, wherein when the instructions are executed, a device where the storage medium is located is controlled to execute the above-mentioned urea injection control method.

[0147] The present application also provides an electronic device, whose structural diagram is as follows: Figure 6As shown, it specifically includes a memory 601 and one or more instructions 602, wherein the one or more instructions 602 are stored in the memory 601 and are configured to be executed by one or more processors 603 to perform the following operations:

[0148] Obtaining a sensor signal collected by a nitrogen oxide sensor of the vehicle within a current time period;

[0149] When it is detected that the sensor signal collected in the current time period meets the preset strong transient condition, a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of the closed-loop control system of the SCR are obtained according to the temperature and airspeed of the SCR system of the vehicle;

[0150] Correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter;

[0151] Correcting the feedforward ammonia-nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia-nitrogen ratio;

[0152] Obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve set value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio;

[0153] The urea injection is controlled according to the required ammonia-nitrogen ratio.

[0154] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0155] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0156] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0157] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0158] The above is a detailed introduction to a urea injection control method provided by the present application. Specific examples are used in this article to illustrate the principle and implementation method of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A urea injection control method, characterized in that: include: Obtaining a sensor signal collected by a nitrogen oxide sensor of the vehicle within a current time period; When it is detected that the sensor signal collected in the current time period meets the preset strong transient condition, a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of a closed-loop control system of the SCR are obtained according to the temperature and airspeed of the selective catalytic reduction SCR system of the vehicle, wherein the closed-loop control system includes a PID control system, and the control parameter basic value includes a PID control parameter; Correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter; Correcting the feedforward ammonia-nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia-nitrogen ratio; Obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve set value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio; The urea injection is controlled according to the required ammonia-nitrogen ratio.

2. The method according to claim 1, characterized in that The process of detecting that the sensor signal collected in the current time period meets the preset strong transient condition includes: Performing integration processing on the sensor signal collected in the current time period to obtain an integral value corresponding to the sensor signal; Determining the transient strength of the sensor signal according to the integral value corresponding to the sensor signal and a preset standard integral value; When the transient intensity of the sensor signal is greater than a preset transient intensity threshold, it is determined that the sensor signal meets a preset strong transient condition.

3. The method according to claim 1, characterized in that The step of correcting the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain the target control parameter includes: Determining a difference value between an ammonia reserve of the SCR system and a preset ammonia reserve setting value, wherein the difference value represents a degree of difference between the ammonia reserve and the ammonia reserve setting value; According to the temperature of the SCR system and the difference value, a preset first configuration file is searched to obtain a correction amount of the basic value of the control parameter; The control parameter basic value is corrected according to the correction amount of the control parameter basic value to obtain the target control parameter.

4. The method according to claim 1, characterized in that The step of correcting the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio includes: querying a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value; The feedforward ammonia-nitrogen ratio basic value is corrected according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

5. The method according to claim 1, characterized in that The step of obtaining a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve set value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio includes: Updating control parameters of the closed-loop control system using the target control parameters; The difference between the ammonia reserve and a preset ammonia reserve set value is input into the updated closed-loop control system to obtain a closed-loop ammonia nitrogen ratio; The required ammonia nitrogen ratio of the SCR system is obtained according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

6. A urea injection control device, characterized in that: include: An acquisition unit, used to acquire a sensor signal collected by a nitrogen oxide sensor of the vehicle within a current time period; A first execution unit is used to obtain a feedforward ammonia nitrogen ratio basic value and a control parameter basic value of a closed-loop control system of the SCR according to a temperature and an airspeed of the SCR system of the vehicle when it is detected that a sensor signal collected in a current time period meets a preset strong transient condition, wherein the closed-loop control system includes a PID control system, and the control parameter basic value includes a PID control parameter; A first correction unit, configured to correct the control parameter base value according to the temperature and ammonia reserve of the SCR system to obtain a target control parameter; a second correction unit, configured to correct the feedforward ammonia nitrogen ratio base value according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a target feedforward ammonia nitrogen ratio; a second execution unit, configured to obtain a required ammonia nitrogen ratio of the SCR system based on the ammonia reserve, a preset ammonia reserve setting value, the closed-loop control system, the target control parameter, and the target feedforward ammonia nitrogen ratio; A control unit is used to control urea injection according to the required ammonia nitrogen ratio.

7. The device according to claim 6, characterized in that The first execution unit includes: The integration subunit is used to integrate the sensor signal collected in the current time period to obtain the integral value corresponding to the sensor signal; A first determining subunit, configured to determine the transient strength of the sensor signal according to an integral value corresponding to the sensor signal and a preset standard integral value; The second determining subunit is used to determine that the sensor signal meets a preset strong transient condition when the transient intensity of the sensor signal is greater than a preset transient intensity threshold.

8. The device according to claim 6, characterized in that The first correction unit comprises: a third determination subunit, configured to determine a difference between the ammonia reserve of the SCR system and a preset ammonia reserve setting value, wherein the difference value represents a degree of difference between the ammonia reserve and the ammonia reserve setting value; A first query subunit, configured to query a preset first configuration file according to the temperature of the SCR system and the difference value, to obtain a correction amount of the basic value of the control parameter; The first correction subunit is used to correct the control parameter basic value according to the correction amount of the control parameter basic value to obtain the target control parameter.

9. The device according to claim 6, characterized in that The second correction unit comprises: A second query subunit is used to query a preset second configuration file according to the temperature of the SCR system and the transient strength of the sensor signal to obtain a correction amount of the feedforward ammonia nitrogen ratio basic value; The second correction subunit is used to correct the feedforward ammonia-nitrogen ratio basic value according to the correction amount of the feedforward ammonia-nitrogen ratio basic value to obtain a target feedforward ammonia-nitrogen ratio.

10. The device according to claim 6, characterized in that The second execution unit includes: An updating subunit, used to update the control parameters of the closed-loop control system using the target control parameters; a first execution subunit, for inputting a difference between the ammonia reserve and a preset ammonia reserve setting value into an updated closed-loop control system to obtain a closed-loop ammonia-nitrogen ratio; The second execution subunit is used to obtain the required ammonia nitrogen ratio of the SCR system according to the target feedforward ammonia nitrogen ratio and the closed-loop ammonia nitrogen ratio.

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