Urea injection control method and device and vehicle

Abstract

The invention provides a urea injection control method and device and a vehicle. For each stage of SCR in a two-stage SCR aftertreatment system, the urea injection amount matched with the stage of SCR is determined based on the target mode started by an engine, the temperature value of an inlet, the exhaust flow, the nitrogen and oxygen concentration and the degradation factor, and on the premise that the emission standard is met, the urea injection amount matched with the stage of SCR can be controlled. The operation mode requirement of the engine and the actual treatment capacity of the selective catalytic reduction device are matched in time, the aftertreatment cost is reduced, the service life of the aftertreatment system is prolonged, and therefore the comprehensive treatment effect of the two-stage SCR aftertreatment system on nitric oxide is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and particularly relates to a urea injection control method, device and vehicle. Background Art

[0002] Currently, due to the fact that the NO conversion ability of the single-stage Selective Catalytic Reduction (SCR) aftertreatment system has approached its limit, in order to meet the increasingly stringent emission regulations, the prior art usually selects a two-stage SCR aftertreatment system. For a two-stage SCR aftertreatment system, it is necessary to coordinately control the urea injection of two nozzles to make the nitrogen oxide (NO) conversion efficiency of the two-stage SCR aftertreatment system reach an optimal level.

[0003] However, the existing urea injection control method for a two-stage SCR aftertreatment system cannot effectively match the actual working conditions of the aftertreatment system, and it is easy to have excessive urea injection, which affects the regeneration performance of the aftertreatment system, resulting in poor comprehensive treatment effect of nitrogen oxides. x ) conversion efficiency to reach an optimal level.

[0004] Summary of the Invention

[0005] Embodiments of the present invention provide a urea injection control method, device and vehicle to solve the problem that the existing urea injection control method for a two-stage SCR aftertreatment system cannot effectively match the actual working conditions of the aftertreatment system, resulting in poor comprehensive treatment effect of nitrogen oxides.

[0006] In a first aspect, embodiments of the present invention provide a urea injection control method applied to a two-stage SCR aftertreatment system. The method includes:

[0007] Obtain a first temperature value, exhaust gas flow rate, first nitrogen oxide concentration, and first degradation factor at the inlet of the front-stage SCR in the two-stage SCR treatment system, and obtain a second temperature value, second degradation factor at the inlet of the rear-stage SCR in the two-stage SCR treatment system, and obtain a target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode or a normal mode;

[0008] Determine a first urea injection amount of the front-stage SCR and a second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first degradation factor;

[0009] Determine a second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration and the second degradation factor;

[0010] ​Control the urea nozzle of the front-stage SCR to inject urea according to the first urea injection amount, and control the urea nozzle of the rear-stage SCR to inject urea according to the second urea injection amount.

[0011] Optionally, in the control method, determining the first urea injection amount of the front-stage SCR and the second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the front nitrogen oxide concentration, and the first degradation factor includes:

[0012] Determine the first ammonia storage value of the front-stage SCR according to the first temperature value and the first nitrogen oxide concentration;

[0013] Determine the first target efficiency of the front-stage SCR according to the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value;

[0014] Determine the first urea injection amount and the second nitrogen oxide concentration according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value.

[0015] Optionally, in the control method, determining the first urea injection amount according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value includes:

[0016] When the target mode is the regeneration mode, obtain the first regeneration degradation factor of the front-stage SCR, and determine the fifth degradation factor according to the first degradation factor and the first regeneration degradation factor;

[0017] When the target mode is the normal mode or the PN reduction mode, determine the first degradation factor as the fifth degradation factor;

[0018] Determine the first urea injection amount according to the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first ammonia storage value, and the fifth degradation factor.

[0019] Optionally, in the control method, determining the second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor includes:

[0020] When the target mode is the regeneration mode, obtain the second regeneration degradation factor of the rear-stage SCR, and determine the sixth degradation factor according to the second degradation factor and the second regeneration degradation factor;

[0021] When the target mode is the normal mode or the PN reduction mode, determine the second deterioration factor as the sixth deterioration factor;

[0022] Determine the second ammonia storage value of the post-stage SCR according to the second temperature value and the second nitrogen oxide concentration;

[0023] Determine the reference efficiency of the post-stage SCR according to the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor and the second ammonia storage value;

[0024] When the target mode is the PN reduction mode, obtain the efficiency correction coefficient of the post-stage SCR, and determine the second target efficiency of the post-stage SCR according to the reference efficiency and the efficiency correction coefficient;

[0025] When the target mode is the regeneration mode or the normal mode, determine the reference efficiency as the second target efficiency of the post-stage SCR;

[0026] Determine the second urea injection amount of the post-stage SCR according to the second target efficiency, the exhaust gas flow rate, the second nitrogen oxide concentration and the second ammonia storage value.

[0027] Optionally, in the control method, obtaining the first regeneration deterioration factor of the pre-stage SCR includes:

[0028] Obtain the first regeneration cycle number of the pre-stage SCR, and determine the first regeneration deterioration factor according to the first regeneration cycle number;

[0029] Obtaining the second regeneration deterioration factor of the post-stage SCR includes:

[0030] Obtain the second regeneration cycle number of the post-stage SCR, and determine the second regeneration deterioration factor according to the second regeneration cycle number.

[0031] Optionally, in the control method, obtaining the efficiency correction coefficient of the post-stage SCR includes:

[0032] Determine the efficiency correction coefficient according to the first target efficiency and the first temperature value.

[0033] Optionally, in the control method, obtaining the first deterioration factor includes:

[0034] Obtain the third deterioration factor of the pre-stage SCR and the first operating mileage of the pre-stage SCR in each deterioration temperature range during the current calculation period; the third deterioration factor is the deterioration factor of the pre-stage SCR after the previous calculation period;

[0035] Determine the first deterioration factor according to the third deterioration factor and the first operating mileage corresponding to each deterioration temperature range;

[0036] The obtaining of the second deterioration factor includes:

[0037] Obtain the fourth deterioration factor of the pre-stage SCR and the second operating mileage of the post-stage SCR in each deterioration temperature range during the current calculation period; the fourth deterioration factor is the deterioration factor of the post-stage SCR after the previous calculation period;

[0038] Determine the second deterioration factor according to the fourth deterioration factor and the second operating mileage corresponding to each deterioration temperature range.

[0039] Optionally, before obtaining the first regeneration deterioration factor of the pre-stage SCR, the control method further includes:

[0040] When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, perform the step of obtaining the first regeneration deterioration factor of the pre-stage SCR;

[0041] Before obtaining the second regeneration deterioration factor of the post-stage SCR, it further includes:

[0042] When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, perform the step of obtaining the second regeneration deterioration factor of the post-stage SCR.

[0043] In a second aspect, an embodiment of the present invention provides a urea injection control device applied to a two-stage SCR after-treatment system, and the device includes:

[0044] An acquisition module, configured to acquire the first temperature value, exhaust gas flow rate, first nitrogen oxide concentration, and first deterioration factor at the inlet of the pre-stage SCR in the two-stage SCR treatment system, and acquire the second temperature value, second deterioration factor at the inlet of the post-stage SCR in the two-stage SCR treatment system, and acquire the target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode, or a normal mode;

[0045] A first determination module, configured to determine the first urea injection amount of the pre-stage SCR and the second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first deterioration factor;

[0046] A second determination module, configured to determine a second urea injection amount of the post-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor;

[0047] An injection control module, configured to control a urea nozzle of the pre-stage SCR to perform urea injection according to the first urea injection amount, and control a urea nozzle of the post-stage SCR to perform urea injection according to the second urea injection amount.

[0048] In a third aspect, an embodiment of the present invention provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus; wherein, the processor, the communication interface, and the memory complete communication with each other through the communication bus;

[0049] The memory is used for storing a computer program;

[0050] The processor is configured to implement the steps in the urea injection control method described in the first aspect above when executing the program stored on the memory.

[0051] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps in the urea injection control method described in the first aspect above are implemented.

[0052] In a fifth aspect, an embodiment of the present invention provides a vehicle, which includes the above-mentioned urea injection control device, or includes the above-mentioned electronic device.

[0053] Regarding the prior art, the present invention has the following advantages:

[0054] In the embodiment of the present invention, first, according to the target mode enabled by the engine, the first temperature value at the inlet of the pre-stage SCR, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first degradation factor, the first urea injection amount of the pre-stage SCR and the second nitrogen oxide concentration at the outlet are determined. Then, based on the above target mode, as well as the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor at the inlet of the post-stage SCR, the second urea injection amount of the post-stage SCR is determined. Then, the urea nozzle of the pre-stage SCR is controlled to perform urea injection according to the first urea injection amount, and the urea nozzle of the post-stage SCR is controlled to perform urea injection according to the second urea injection amount. Among them, for each stage of SCR in the dual-stage SCR after-treatment system, the urea injection amount matching this stage of SCR is determined respectively based on the target mode enabled by the engine, the temperature value at the inlet, the exhaust gas flow rate, the nitrogen oxide concentration, and the degradation factor, which can meet the emission standards, timely match the operation mode requirements of the engine and the actual processing capacity of the selective catalytic reduction device, reduce the after-treatment cost, extend the service life of the after-treatment system, and thus effectively improve the comprehensive treatment effect of the dual-stage SCR after-treatment system on nitrogen oxides.

[0055] The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specific embodiments of the present invention are given. Brief Description of the Drawings

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments.

[0057] Figure 1 It is a schematic diagram of a traditional post-treatment system;

[0058] Figure 2 It is a schematic flow chart of a urea injection control method provided by an embodiment of the present invention;

[0059] Figure 3 It is a schematic diagram of the structure of a bipolar SCR post-treatment system in an embodiment of the present invention;

[0060] Figure 4 It is a schematic diagram of a technical route of a bipolar SCR post-treatment system in an embodiment of the present invention;

[0061] Figure 5 It is another schematic diagram of a technical route of a bipolar SCR post-treatment system in an embodiment of the present invention;

[0062] Figure 6 It is a schematic diagram of a deterioration factor structure model in an embodiment of the present invention;

[0063] Figure 7 It is a schematic diagram of a urea injection amount model in the regeneration mode in an embodiment of the present invention;

[0064] Figure 8 It is a schematic diagram of a urea injection control device provided by an embodiment of the present invention;

[0065] Figure 9 It is a block diagram of an electronic device provided by an embodiment of the present invention. Detailed Embodiments

[0066] The exemplary embodiments of the present invention will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0067] The main pollutants emitted by diesel engines mainly include CO, HC, NOx, soot, etc., which pollute the environment and threaten human health at the same time. Traditional aftertreatment systems generally use a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR). As Figure 1 shown, the engine exhaust gas enters the SCR after passing through the DOC and DPF. When the gas temperature before the SCR inlet reaches the injection start value, the urea injection unit injects urea into the exhaust pipe in front of the SCR. The urea droplets are atomized, evaporated, and decomposed in the exhaust pipe to form NH3, and NH3 and NO x are mixed evenly in the mixing chamber and then enter the SCR, where they react on the active sites of the catalyst in the carrier to generate N2 and H2O, thereby effectively reducing the nitrogen oxide pollutants in the exhaust gas.

[0068] In order to meet the increasingly strict emission regulations, the existing technology usually selects a two-stage SCR aftertreatment system.

[0069] For a two-stage SCR aftertreatment system, it is necessary to coordinate and control the urea injection of two nozzles to make the nitrogen oxide (NO x ) conversion efficiency of the two-stage SCR aftertreatment system reach an optimal level.

[0070] However, the existing urea injection control method for a two-stage SCR aftertreatment system cannot effectively match the actual working conditions of the aftertreatment system, and it is easy to have situations such as over-injection of urea and affecting the regeneration performance of the aftertreatment system, resulting in poor comprehensive treatment effect of nitrogen oxides.

[0071] To solve the above problems, an embodiment of the present invention provides a urea injection control method, which is applied to the two-stage SCR aftertreatment system of a vehicle. As Figure 2 shown, it includes steps 101 to 104.

[0072] The urea injection control method provided by the embodiment of the present invention is suitable for a vehicle driven by a diesel engine, and the vehicle has a two-stage SCR aftertreatment system. Among them, as Figure 3 shown, the two-stage SCR aftertreatment system includes a front-stage SCR11 and a rear-stage SCR12. A first temperature sensor 13 and a first NOx sensor 14 are arranged in front of the front-stage SCR11 to measure the inlet temperature and nitrogen-oxygen concentration of the front-stage SCR respectively; a second temperature sensor 15 and a second NOx sensor 16 are arranged in front of the rear-stage SCR to measure the inlet temperature and nitrogen-oxygen concentration of the rear-stage SCR respectively.

[0073] In addition, a first urea nozzle 17 is arranged in front of the front-stage SCR, and a second urea nozzle 18 is arranged in front of the rear-stage SCR; when the first temperature sensor and the second temperature sensor reach the set value of the starting injection temperature, the first urea nozzle and the second urea nozzle can respectively inject urea into the exhaust pipe in front of the front-stage SCR and the rear-stage SCR; in addition, during cold start of the engine, since the front-stage SCR is arranged closer to the turbine end, the urea starting injection threshold temperature is reached first, so that the second urea nozzle starts to inject urea into the exhaust pipe; subsequently, when the inlet temperature of the rear-stage SCR reaches the urea starting injection threshold temperature, then the second urea nozzle starts to inject urea.

[0074] Optionally, a third NOx sensor 19 is further arranged behind the rear-stage SCR to measure the nitrogen oxide concentration at the outlet of the rear-stage SCR, so as to optimize the urea injection strategies of the first urea nozzle and the second urea nozzle.

[0075] Optionally, in one embodiment, as Figure 4 shown, in the order of the exhaust gas flow direction, in the double-stage SCR after-treatment system provided by the embodiment of the present application, the front-stage SCR, DOC, DPF and rear-stage SCR are arranged in sequence, that is, the double-stage SCR after-treatment system adopts the technical route of SCR+SCR.

[0076] Optionally, in another embodiment, as Figure 5 shown, in the order of the exhaust gas flow direction, in the double-stage SCR after-treatment system provided by the embodiment of the present application, DOC, front-stage SCR+DPF and rear-stage SCR are arranged in sequence, and the front-stage SCR coating is applied on the particulate trap (DPF), that is, the double-stage SCR after-treatment system adopts the technical route of SCRonDPF+SCR, so that the front-stage SCR simultaneously has the particulate trapping ability and the nitrogen oxide conversion ability.

[0077] Step 101, obtain the first temperature value, exhaust gas flow rate, first nitrogen oxide concentration, first degradation factor at the inlet of the front-stage SCR in the double-stage SCR treatment system, and obtain the second temperature value, second degradation factor at the inlet of the rear-stage SCR in the double-stage SCR treatment system, and obtain the target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode or a normal mode.

[0078] In this step, the front-stage SCR is the SCR closer to the engine among the two SCRs, that is, the SCR that the exhaust gas passes through first; and the rear-stage SCR is the SCR farther from the engine among the two SCRs, that is, the SCR that the exhaust gas passes through later.

[0079] In this step, the above exhaust gas flow rate is the exhaust gas flow rate entering the double-stage SCR treatment system, the exhaust gas temperature is obtained through the first temperature sensor at the inlet of the front-stage SCR as the above first temperature value, and the first NO at the inlet of the front-stage SCRx The sensor acquires the above first nitrogen oxide concentration, and at the same time, determines the above first deterioration factor according to the aging state of the pre-stage SCR.

[0080] In this step, the exhaust gas temperature is acquired as the above second temperature value by a second temperature sensor at the inlet of the post-stage SCR, and at the same time, the above second deterioration factor is determined according to the aging state of the post-stage SCR.

[0081] In this step, the regeneration mode is a mode for enhancing the regeneration mileage of the Diesel Particulate Filter (DPF). When the engine can enable this mode, it indicates that it is necessary to take into account the passive regeneration ability of the particulate filter (DPF) in the aftertreatment system. Otherwise, it is easy to result in a lower regeneration mileage. Therefore, the regeneration mileage can be extended by turning on the regeneration mode; the PN reduction mode is a mode for reducing the particulate number, and whether to use the PN reduction mode can be selected by a switch quantity; the normal mode is other modes except the regeneration mode and the PN reduction mode.

[0082] Step 102: Determine the first urea injection amount of the pre-stage SCR and the second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first deterioration factor.

[0083] In this step, the first deterioration factor is the degree of decline or deterioration of the nitrogen oxide conversion performance in the pre-stage SCR due to irreversible physical, chemical, or mechanical processes. This first deterioration factor can specifically be the deterioration factor of the pre-stage SCR carrier; since the target mode reflects the processing requirements of the aftertreatment system itself, the first deterioration factor reflects the actual processing capacity of the pre-stage SCR, and the first temperature value, exhaust gas flow rate, and first nitrogen oxide concentration affect the theoretical processing efficiency of the pre-stage SCR for nitrogen oxides. Therefore, based on the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first deterioration factor, the first target efficiency of the pre-stage SCR can be determined, so that it can not only meet the processing requirements of the aftertreatment system itself, but also match its actual processing capacity, and can also jointly treat the tail gas with the post-stage SCR to meet the regulatory emission standards.

[0084] In this step, after determining the first target efficiency, based on the principle of urea participating in nitrogen oxide conversion, combined with the above exhaust gas flow rate and first nitrogen oxide concentration, the corresponding urea injection amount and the second nitrogen oxide concentration after being treated by the pre-stage SCR can be determined.

[0085] Step 103: Determine the second urea injection amount of the post-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second deterioration factor.

[0086] In this step, the second deterioration factor is the degree of decline or deterioration in the nitrogen oxide conversion performance of the post-stage SCR caused by irreversible physical, chemical, or mechanical processes. Specifically, the second deterioration factor can be the deterioration factor of the post-stage SCR carrier. Since the target mode reflects the processing requirements of the aftertreatment system itself, the second deterioration factor reflects the actual processing capacity of the post-stage SCR, while the second temperature value, exhaust gas flow rate, and second nitrogen oxide concentration affect the theoretical processing efficiency of the post-stage SCR for nitrogen oxides. Therefore, based on the target mode, the second temperature value, exhaust gas flow rate, second nitrogen oxide concentration, and second deterioration factor, the second target efficiency of the post-stage SCR can be determined, enabling it to not only meet the processing requirements of the aftertreatment system itself, but also match its actual processing capacity, and jointly with the pre-stage SCR, treat the tail gas to meet the regulatory emission standards.

[0087] Step 104: Control the urea nozzle of the pre-stage SCR to inject urea according to the first urea injection amount, and control the urea nozzle of the post-stage SCR to inject urea according to the second urea injection amount.

[0088] In this step, by controlling the first urea nozzle arranged in front of the pre-stage SCR to inject urea according to the first urea injection amount, the exhaust gas can be treated to the second nitrogen oxide concentration state, and then by controlling the second urea nozzle arranged in front of the post-stage SCR to inject urea according to the second urea injection amount, the tail gas can be treated to meet the regulatory emission standards.

[0089] In the embodiment of the present invention, for each stage of SCR in the dual-stage SCR aftertreatment system, based on the target mode enabled by the engine, the temperature value at the inlet, exhaust gas flow rate, nitrogen oxide concentration, and deterioration factor, the urea injection amount matching this stage of SCR is determined respectively. It can, on the premise of meeting the emission standards, timely match the operation mode requirements of the engine and the actual processing capacity of the selective catalytic reduction device, reduce the aftertreatment cost, extend the service life of the aftertreatment system, and thus effectively improve the comprehensive treatment effect of the dual-stage SCR aftertreatment system on nitrogen oxides.

[0090] Optionally, in an implementation manner, obtaining the first deterioration factor includes steps 111 to 112:

[0091] Step 111: Obtain the third deterioration factor of the pre-stage SCR and the first operating mileage of the pre-stage SCR in each deterioration temperature range during the current calculation cycle; the third deterioration factor is the deterioration factor of the pre-stage SCR after the previous calculation cycle.

[0092] In this step, the third degradation factor is the degradation factor of the previous-stage SCR determined in the previous calculation period, that is, the historical degradation factor of the previous-stage SCR; the calculation period is the update period of the degradation factor, which can be a fixed time or a single driving process.

[0093] In this step, the inlet temperature of the previous-stage SCR is pre-divided into multiple intervals according to the degradation rate of the carrier in the previous-stage SCR, as the above-mentioned degradation temperature intervals, and the driving mileage of the vehicle in each degradation temperature interval is continuously recorded within a single calculation period, as the above-mentioned first driving mileage.

[0094] Step 112: Determine the first degradation factor according to the third degradation factor and the first driving mileage corresponding to each degradation temperature interval.

[0095] In this step, since the first degradation rate of the carrier in the previous-stage SCR is related to the exhaust gas temperature at its inlet, and the first driving mileage corresponding to each degradation temperature interval reflects the cumulative degradation duration of the carrier in each degradation temperature interval, and the first degradation factor is the accumulation of the degradation rate, therefore, the newly added degradation amount can be determined based on the first driving mileage corresponding to each degradation temperature interval, and combined with the third degradation factor, the current degradation factor of the carrier in the previous-stage SCR can be determined.

[0096] Optionally, in a specific implementation manner, the corresponding degradation coefficients can be preset for different degradation temperature intervals according to the degradation rate of the carrier in the previous-stage SCR in different degradation temperature intervals, where the higher the temperature of the degradation temperature interval, the larger the corresponding degradation coefficient; then the first driving mileage corresponding to each degradation temperature interval is multiplied by the degradation coefficient and summed, and then added to the third degradation factor, and the above-mentioned first degradation factor can be determined.

[0097] In this implementation manner, the corresponding first degradation factor is continuously updated according to the first driving mileage of the previous-stage SCR in each degradation temperature interval, so that the first degradation factor can accurately reflect the actual degradation degree of the previous-stage SCR carrier, thereby more accurately and reasonably controlling the urea injection.

[0098] Optionally, in an implementation manner, obtaining the second degradation factor includes steps 113 to 114:

[0099] Step 113: Obtain the fourth degradation factor of the previous-stage SCR and the second driving mileage of the subsequent-stage SCR in each degradation temperature interval during the current calculation period; the fourth degradation factor is the degradation factor of the subsequent-stage SCR after the previous calculation period.

[0100] In this step, the fourth deterioration factor is the deterioration factor of the post-stage SCR determined in the previous calculation period, that is, the historical deterioration factor of the post-stage SCR; the calculation period is the update period of the deterioration factor, which can be calculated and updated in real time, or updated at a specific time (e.g., each regeneration), can be updated at a fixed time, or updated after a driving process.

[0101] In this step, the inlet temperature of the post-stage SCR is pre-divided into multiple intervals according to the deterioration rate of the carrier in the pre-stage SCR as the above-mentioned deterioration temperature intervals, and the driving mileage of the vehicle in each deterioration temperature interval is continuously recorded within a single calculation period as the above-mentioned second driving mileage.

[0102] Step 114: Determine the second deterioration factor according to the fourth deterioration factor and the second driving mileage corresponding to each deterioration temperature interval.

[0103] In this step, since the second deterioration rate of the carrier in the post-stage SCR is related to the exhaust gas temperature at its inlet, and the second driving mileage corresponding to each deterioration temperature interval reflects the cumulative deterioration duration of the carrier in each deterioration temperature interval, and the second deterioration factor is the accumulation of the deterioration rate, therefore, the new deterioration degree can be determined based on the second driving mileage corresponding to each deterioration temperature interval, and combined with the fourth deterioration factor, the current deterioration factor of the carrier in the post-stage SCR can be determined.

[0104] Optionally, in a specific embodiment, the corresponding deterioration coefficients can be preset for different deterioration temperature intervals according to the deterioration rate of the carrier in the post-stage SCR in different deterioration temperature intervals, where the higher the temperature of the deterioration temperature interval, the greater the corresponding deterioration coefficient; then, the second driving mileage corresponding to each deterioration temperature interval is multiplied by the deterioration coefficient and summed, and then added to the fourth deterioration factor to determine the above-mentioned second deterioration factor.

[0105] Exemplarily, if the inlet temperature regions of the pre-stage SCR and the post-stage SCR are divided into a low deterioration speed region, a medium speed region, and a high speed region, the deterioration factor is calculated according to the following formula (1):

[0106] f N =α low ×S low +α med ×S med +α high ×S high +f N-1

[0107] Where f N-1 is the deterioration factor calculated last time, f N is the newly calculated deterioration factor, S low 、S med 、Shigh respectively refer to the operating mileage under the current low, medium, and high-speed deterioration regions, α low , α med , α high are respectively the deterioration coefficients corresponding to the low, medium, and high-speed deterioration regions.

[0108] In this embodiment, according to the second operating mileage of the pre-stage SCR in each deterioration temperature range, the corresponding second deterioration factor is continuously updated, so that the second deterioration factor can accurately reflect the actual deterioration degree of the post-stage SCR carrier, thereby more accurately and reasonably controlling urea injection.

[0109] Optionally, in another embodiment, in this specific embodiment, as Figure 6 shown, the vehicle running time, vehicle speed, driving mileage, and carrier temperature are used as input quantities, and the first deterioration factor and the second deterioration factor are respectively calculated, so as to consider the aging of the SCR carrier during the normal operation of the vehicle and control urea injection.

[0110] In this embodiment, considering that the temperature is relatively high during the regeneration process, which will accelerate the aging of the carrier, the regeneration factor needs to be considered separately. Especially when the SCR1 adopts the SCRonDPF technical route, therefore, the number of regenerations during the vehicle operation needs to be used as an input quantity to calculate the regeneration deterioration factors of the pre-stage SCR and the post-stage SCR respectively, so as to correct the deterioration factors caused by the above natural aging.

[0111] Optionally, in one embodiment, step 102 described above includes steps 121 to 124:

[0112] Step 121: Determine the first ammonia storage value of the pre-stage SCR according to the first temperature value and the first nitrogen oxide concentration.

[0113] In this step, since urea needs to be decomposed into ammonia after entering the SCR, and ammonia needs to be adsorbed on the catalyst active sites in the SCR first, and then NO in the exhaust gas x reacts with the ammonia adsorbed on the catalyst at the catalyst active sites, and the above ammonia storage value is used to calculate the current reaction efficiency and the amount of ammonia that needs to be additionally stored in the catalyst in the pre-stage SCR for NO x conversion. It is directly related to the exhaust gas temperature and the first nitrogen oxide concentration, so the first ammonia storage value of the pre-stage SCR can be determined based on the above two.

[0114] Step 122: Determine the first target efficiency of the pre-stage SCR according to the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value.

[0115] In this step, based on the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value, the first efficiency relationship curve of the pre-stage SCR is searched, or the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value are input into the efficiency model of the pre-stage SCR to directly obtain the above-mentioned first target efficiency; wherein, the above-mentioned first efficiency relationship curve is an ideal efficiency curve of the pre-stage SCR set in advance based on the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value, and this first efficiency relationship curve can be an efficiency setting table; the efficiency model of the pre-stage SCR is a model that is pre-trained and takes the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value as input quantities, and takes the first target efficiency, the first urea injection amount, and the second nitrogen oxide concentration as output quantities.

[0116] Optionally, in the embodiments of the present application, the first actual nitrogen oxide concentration at the outlet of the pre-stage SCR is also obtained through a second NO x sensor to facilitate calculating the actual conversion efficiency of the pre-stage SCR in combination with the first nitrogen oxide concentration, and correcting or optimizing and adjusting the above-mentioned first efficiency relationship curve or the efficiency model of the pre-stage SCR.

[0117] Step 123: Determine the first urea injection amount and the second nitrogen oxide concentration according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value.

[0118] In this step, since in order to meet the first target efficiency, the first urea injection amount of the pre-stage SCR is mainly affected by the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first ammonia storage value, and it is also necessary to meet the processing requirements of the aftertreatment system itself and combine its own actual processing capacity, therefore, according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value, the corresponding urea injection amount can be determined as the above-mentioned first urea injection amount. At the same time, the nitrogen oxide concentration downstream of it, that is, the above-mentioned second nitrogen oxide concentration, can also be determined.

[0119] In this implementation manner, first, based on the first temperature value and the first nitrogen oxide concentration at the inlet of the pre-stage SCR, the matching first ammonia storage value is determined, and then, in combination with the first temperature value, the first nitrogen oxide concentration, and the first deterioration factor, the corresponding first target efficiency, the first urea injection amount, and the second nitrogen oxide concentration downstream are accurately matched.

[0120] Optionally, in a specific implementation manner, the above-mentioned step 123 includes steps 231 to 233:

[0121] Step 231: When the target mode is the regeneration mode, obtain the first regeneration deterioration factor of the upstream SCR, and determine the fifth deterioration factor according to the first deterioration factor and the first regeneration deterioration factor.

[0122] In this step, the first regeneration deterioration factor is the deterioration factor related to regeneration in the upstream SCR, while the first deterioration factor is the deterioration factor under non-regeneration working conditions; since the regeneration performance of the upstream SCR is affected by both the first regeneration deterioration factor and the first deterioration factor, thus when the target mode is the regeneration mode, especially when adopting the SCR on DPF technical route, the temperature is relatively high during the regeneration process, which will accelerate the aging of the carrier, so it is necessary to correct the first deterioration factor with the regeneration deterioration factor to obtain the above-mentioned fifth deterioration factor.

[0123] Step 232: When the target mode is the normal mode or the PN reduction mode, determine the first deterioration factor as the fifth deterioration factor.

[0124] In this step, when the target mode is the normal mode or the PN reduction mode, that is, in the non-regeneration mode, there is no need to consider the regeneration performance, so directly use the above-mentioned first deterioration factor as the fifth deterioration factor, and the determined urea injection amount can treat the exhaust gas to meet the emission requirements.

[0125] Step 233: Determine the first urea injection amount according to the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first ammonia storage value and the fifth deterioration factor.

[0126] In this step, calculate the urea injection amount for the upstream SCR to reach the above-mentioned first target efficiency from the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first ammonia storage value and the fifth deterioration factor, and use it as the above-mentioned first urea injection amount.

[0127] Optionally, the above-mentioned first urea injection amount is calculated according to the following formulas (2) - (3):

[0128] Urea Cor1 =(dm NOx1 ×f stoich ×η1+dm NH3Ld1 )×R×fac1 (2)

[0129]

[0130] where, Urea Cor1 is the first urea injection amount, dm NOx1 is the upstream NO x mass flow rate of the upstream SCR, is the exhaust gas flow rate, c1 is the first nitrogen oxide concentration, fstoich is the stoichiometric ratio when ammonia and nitrogen oxides react completely, η1 is the first target efficiency, dm NH3Ld1 is the first ammonia storage value, R is a constant related to the mass concentration of the urea solution, and fac1 is the fifth degradation factor.

[0131] Among them, when the mass concentration of the urea solution is 32.5%, this R is 5.425.

[0132] Optionally, the above-mentioned fifth degradation factor is calculated according to the following formula (4):

[0133] fac1 = f T1 ×f N1 (4)

[0134] Among them, f T1 is the first regeneration degradation factor, and f N1 is the first degradation factor.

[0135] In the above specific implementation manner, when the engine enables the regeneration mode, the first degradation factor is corrected by using the first regeneration degradation factor to achieve the correction of the injection amount, thereby reducing the urea injection amount of the pre-stage SCR, reducing the competition between ammonia and carbon particles for NO2, enhancing passive regeneration, and increasing the regeneration mileage.

[0136] Optionally, in a specific implementation manner, before obtaining the first regeneration degradation factor of the pre-stage SCR, it further includes:

[0137] When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, the step of obtaining the first regeneration degradation factor of the pre-stage SCR is executed.

[0138] In this specific implementation manner, the flow rate threshold, the speed threshold, and the vehicle speed threshold are respectively the exhaust gas flow rate value, the engine speed value, and the vehicle speed value for determining that the vehicle is not in the idle or low-speed working condition. When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, and the vehicle speed is greater than or equal to the vehicle speed threshold, the idle or low-speed working condition can be excluded.

[0139] In this specific embodiment, the temperature threshold is the temperature value that defines whether the downstream SCR carrier is in the high-efficiency nitrogen oxide conversion region, and the concentration threshold is the nitrogen oxide concentration value downstream of the upstream SCR for determining whether the urea in the upstream SCR can be reduced in injection; when the second temperature value is greater than or equal to the temperature threshold and the second nitrogen oxide concentration is less than the concentration threshold, it indicates that the downstream SCR carrier is in the high-efficiency nitrogen oxide conversion region and the nitrogen oxide value downstream of the upstream SCR is low enough. At this time, the urea injection in the upstream SCR is slightly reduced, and the exhaust gas treated by the downstream SCR can also meet the emission requirements. Therefore, the first regeneration degradation factor can be obtained and the first degradation factor can be corrected, thereby reducing the urea injection amount of the upstream SCR, reducing the competition between NH3 and carbon particles for NO2, enhancing the passive regeneration of the upstream SCR, and increasing the regeneration mileage.

[0140] In this specific embodiment, as Figure 7 shown, in the case of adopting the SCR on DPF technical route, if the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature value is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, then the regeneration degradation factor can be obtained and the first urea injection amount can be corrected in combination with the first degradation factor, thereby reducing the urea injection amount of the upstream SCR, reducing the competition between NH3 and carbon particles for NO2, enhancing the passive regeneration of the upstream SCR, and increasing the regeneration mileage.

[0141] Optionally, in a specific embodiment, obtaining the first regeneration degradation factor of the upstream SCR specifically includes:

[0142] Obtaining the first regeneration cycle number of the upstream SCR, and determining the first regeneration degradation factor according to the first regeneration cycle number.

[0143] In this specific embodiment, multiple regeneration cycles are pre-performed on the bench, the aging rate of the upstream SCR is measured, the degradation factor of the average single regeneration is calculated, and then superimposed according to the number of times, so that the first regeneration degradation factor corresponding to the first regeneration cycle number can be quickly determined.

[0144] In practical applications, the first regeneration times can be segmented in advance, and the corresponding first regeneration degradation factors for the corresponding number segments are recorded. The number segment where the first regeneration number is located is determined, and then the corresponding first regeneration degradation factor can be obtained.

[0145] Exemplarily, the regeneration times can be divided into multiple number segments such as (0 - 50], (50 - 100], (100 - 130], (130 - 160], (160 - 180], etc., and the corresponding regeneration degradation factors can be set to 1.02, 1.03, 1.05, 1.07, 1.1; among them, when the regeneration number is 0, the corresponding regeneration degradation factor is 1.

[0146] Optionally, in one embodiment, step 103 above includes steps 131 to 137:

[0147] Step 131: When the target mode is the regeneration mode, obtain the second regeneration deterioration factor of the post-stage SCR, and determine the sixth deterioration factor according to the second deterioration factor and the second regeneration deterioration factor.

[0148] In this step, the second regeneration deterioration factor is the deterioration factor related to regeneration in the post-stage SCR, and the second deterioration factor is the deterioration factor under non-regeneration conditions; since the regeneration performance of the post-stage SCR is affected by both the second regeneration deterioration factor and the second deterioration factor, when the target mode is the regeneration mode, especially when using the SCR on DPF technical route, the temperature is relatively high during the regeneration process, which will accelerate the aging of the carrier. Therefore, it is necessary to correct the second deterioration factor with the second regeneration deterioration factor to obtain the above-mentioned sixth deterioration factor.

[0149] Step 132: When the target mode is the normal mode or the PN reduction mode, determine the second deterioration factor as the sixth deterioration factor.

[0150] In this step, when the target mode is the normal mode or the PN reduction mode, that is, in the non-regeneration mode, there is no need to consider the regeneration performance. Therefore, the second deterioration factor is directly used as the sixth deterioration factor, and the determined urea injection amount can treat the exhaust gas to meet the emission requirements.

[0151] Step 133: Determine the second ammonia storage value of the post-stage SCR according to the second temperature value and the second nitrogen oxide concentration.

[0152] In this step, since urea needs to be decomposed into ammonia after entering the SCR, and ammonia needs to be adsorbed on the catalyst active sites in the SCR first, and then NOx in the exhaust gas reacts with the ammonia adsorbed on the catalyst at the catalyst active sites. The above ammonia storage value is used to calculate the current reaction efficiency and the amount of ammonia that needs to be additionally stored in the catalyst of the pre-stage SCR for NOx conversion. It is directly related to the exhaust gas temperature and the second nitrogen oxide concentration. Therefore, the second ammonia storage value of the post-stage SCR can be determined based on the above two.

[0153] Step 134: Determine the reference efficiency of the post-stage SCR according to the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value.

[0154] In this step, according to the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value, the second efficiency relationship curve of the post-stage SCR is found, or the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value are input into the efficiency model of the post-stage SCR to directly obtain the above-mentioned reference efficiency; wherein, the above-mentioned second efficiency relationship curve is an ideal efficiency curve of the post-stage SCR set in advance based on the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value, and this second efficiency relationship curve can be an efficiency setting table; the efficiency model of the above-mentioned post-stage SCR is a model that is pre-trained and takes the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value as input quantities, and takes the reference efficiency, the second urea injection amount, and the third nitrogen oxide concentration as output quantities, wherein, the third nitrogen oxide concentration is the theoretical nitrogen oxide concentration downstream of the post-stage SCR, so as to facilitate subsequent correction or optimization adjustment of the above-mentioned second efficiency relationship curve or the efficiency model of the post-stage SCR in combination with the actual nitrogen oxide concentration at the outlet of the post-stage SCR.

[0155] Optionally, in the embodiments of the present application, the second actual nitrogen oxide concentration at the SCR outlet is also obtained, so as to calculate the actual conversion efficiency of the post-stage SCR in combination with the first actual nitrogen oxide concentration, and correct or optimize the above-mentioned second efficiency relationship curve or the efficiency model of the post-stage SCR, so as to facilitate subsequent correction or optimization adjustment of the above-mentioned second efficiency relationship curve or the efficiency model of the post-stage SCR in combination with the actual nitrogen oxide concentration at the outlet of the post-stage SCR.

[0156] Step 135, when the target mode is the PN reduction mode, obtain the efficiency correction coefficient of the post-stage SCR, and determine the second target efficiency of the post-stage SCR according to the reference efficiency and the efficiency correction coefficient.

[0157] In this step, because when the engine enables the PN reduction mode, it is necessary to reduce the particulate matter quantity after the post-stage SCR to prevent the problem of over-injection of urea at the post-stage SCR when the NO x concentration rises steeply during sudden acceleration of the vehicle when the carrier temperature of the pre-stage SCR is in the low-efficiency nitrogen oxide conversion area.

[0158] Optionally, in a specific embodiment, obtaining the efficiency correction coefficient of the post-stage SCR includes:

[0159] Determine the efficiency correction coefficient according to the first target efficiency and the first temperature value.

[0160] In this specific embodiment, since the efficiency correction range of the post-stage SCR is related to the NOx conversion efficiency of the pre-stage SCR, and the influence degree of the pre-stage SCR on the carrier temperature is different under different NOx conversion efficiency states, the corresponding relationship between the target efficiency of the pre-stage SCR, the carrier temperature value thereof and the efficiency correction coefficient of the post-stage SCR can be established in advance according to the emission requirements of the PN reduction mode in combination with the tail gas emission standard, and then based on the determined first target efficiency and the first temperature value of the pre-stage SCR, the corresponding efficiency correction coefficient can be found out.

[0161] Specifically, the second target efficiency is calculated according to the following formula (5):

[0162] η2 = η cor ×fac cor (5)

[0163] Wherein, η2 is the second target efficiency, η cor is the reference efficiency, and fac cor is the efficiency correction coefficient.

[0164] Step 136: When the target mode is the regeneration mode or the normal mode, determine the reference efficiency as the second target efficiency of the post-stage SCR.

[0165] In this step, when the target mode is the regeneration mode or the normal mode, that is, in the case of the non-PN reduction mode, the problem of particulate matter quantity does not need to be considered, so the above reference efficiency can be directly used as the second target efficiency to participate in the calculation of the second urea injection amount of the post-stage SCR, and the exhaust gas can be processed to meet the emission requirements.

[0166] Step 137: Determine the second urea injection amount of the post-stage SCR according to the second target efficiency, the exhaust gas flow rate, the second NOx concentration, the sixth degradation factor and the second ammonia storage value.

[0167] In this step, the urea injection amount for the post-stage SCR to reach the above second target efficiency is calculated from the second target efficiency, the exhaust gas flow rate, the second NOx concentration, the sixth degradation factor and the second ammonia storage value, and used as the above second urea injection amount.

[0168] Optionally, the above second urea injection amount is calculated according to the following formulas (6) - (7):

[0169] Urea Cor2 = (dm NOx2 ×f stoich ×η2 + dm NH3Ld2 ) × R × fac2 (6)

[0170]

[0171] wherein, Urea Cor2 is the second urea injection amount, in dm NOx2 is the upstream NO of the post-stage SCR x mass flow rate is the exhaust gas flow rate, c2 is the second nitrogen oxide concentration, f stoich is the stoichiometric ratio when urea and nitrogen oxides react completely, η2 is the first target efficiency, in dm NH3Ld2 is the second ammonia storage value, R is a constant related to the mass concentration of the urea solution, fac2 is the sixth degradation factor.

[0172] Wherein, when the mass concentration of the urea solution is 32.5%, this R is 5.425.

[0173] Optionally, the above-mentioned sixth degradation factor is calculated according to the following formula (8):

[0174] fac2 = f T2 × f N2 (8)

[0175] Wherein, f T2 is the second regeneration degradation factor, f N1 is the second degradation factor.

[0176] In the above specific implementation manner, when the engine enables the PN reduction mode, based on the first target efficiency of the pre-stage SCR and the first temperature value of the carrier, determine the efficiency correction coefficient of the post-stage SCR, and use this efficiency correction coefficient to adjust the baseline efficiency of the post-stage SCR, thereby reducing the urea injection amount of the post-stage SCR, and thus avoiding the problem of excessive particulate matter caused by overspray of urea.

[0177] Optionally, in a specific implementation manner, before obtaining the second regeneration degradation factor of the post-stage SCR, it further includes:

[0178] When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, perform the step of obtaining the second regeneration degradation factor of the post-stage SCR.

[0179] In this specific implementation manner, the flow rate threshold, the speed threshold, and the vehicle speed threshold are respectively the exhaust gas flow rate value, the engine speed value, and the vehicle speed value for determining that the vehicle is not in the idle or low-speed condition. When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, and the vehicle speed is greater than or equal to the vehicle speed threshold, the idle or low-speed condition can be excluded.

[0180] In this specific embodiment, the temperature threshold is the temperature value for defining whether the post-stage SCR carrier is in the high-efficiency nitrogen oxide conversion region, and the concentration threshold is the nitrogen oxide concentration value downstream of the pre-stage SCR for determining whether the urea in the pre-stage SCR can be reduced in injection; when the second temperature value is greater than or equal to the temperature threshold and the second nitrogen oxide concentration is less than the concentration threshold, it indicates that the post-stage SCR carrier is in the high-efficiency nitrogen oxide conversion region and the nitrogen oxide value downstream of the pre-stage SCR is low enough. At this time, the urea in the pre-stage SCR is slightly reduced in injection, and the exhaust gas treated by the post-stage SCR can also meet the emission requirements. Therefore, the second regeneration deterioration factor can be obtained and the second deterioration factor can be corrected, thereby reducing the urea injection amount of the post-stage SCR, reducing the competition between NH3 and carbon particles for NO2, enhancing the passive regeneration of the post-stage SCR, and increasing the regeneration mileage.

[0181] Optionally, in a specific embodiment, obtaining the second regeneration deterioration factor of the post-stage SCR specifically includes:

[0182] Obtaining the second regeneration cycle number of the post-stage SCR, and determining the second regeneration deterioration factor according to the second regeneration cycle number.

[0183] In this specific embodiment, multiple regeneration cycles are pre-performed on the test bench, the aging rate of the post-stage SCR is measured, the deterioration factor of the average single regeneration is calculated, and then superimposed according to the number of times, so that the second regeneration deterioration factor corresponding to the second regeneration cycle number can be quickly determined.

[0184] In practical applications, the second regeneration times can be segmented in advance, and the corresponding second regeneration deterioration factors for the corresponding number segments are recorded. The number segment is determined by the second regeneration times, and then the corresponding second regeneration deterioration factor can be obtained.

[0185] Exemplarily, the regeneration times can be divided into multiple number segments such as (0 - 50], (50 - 100], (100 - 130], (130 - 160], (160 - 180], etc., and the corresponding regeneration deterioration factors can be set to 1.02, 1.03, 1.05, 1.07, 1.1; among them, when the regeneration times is 0, the corresponding regeneration deterioration factor is 1.

[0186] Figure 8 It is a schematic diagram of a urea injection control device provided by an embodiment of the present invention, which is applied to a dual-stage SCR post-treatment system. The device includes:

[0187] An acquisition module 81, configured to acquire a first temperature value, an exhaust gas flow rate, a first nitrogen oxide concentration, a first deterioration factor at the inlet of the front-stage SCR in the two-stage SCR treatment system, and acquire a second temperature value, a second deterioration factor at the inlet of the rear-stage SCR in the two-stage SCR treatment system, and acquire a target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode, or a normal mode;

[0188] A first determination module 82, configured to determine a first target efficiency, a first urea injection amount, and a second nitrogen oxide concentration at the outlet of the front-stage SCR according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first deterioration factor;

[0189] A second determination module 83, configured to determine a second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second deterioration factor;

[0190] An injection control module 84, configured to control the urea nozzle of the front-stage SCR to inject urea according to the first urea injection amount, and control the urea nozzle of the rear-stage SCR to inject urea according to the second urea injection amount.

[0191] Optionally, in the control device, the first determination module 82 includes:

[0192] A first determination unit, configured to determine a first ammonia storage value of the front-stage SCR according to the first temperature value and the first nitrogen oxide concentration;

[0193] A second determination unit, configured to determine a first target efficiency of the front-stage SCR according to the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value;

[0194] A third determination unit, configured to determine the first urea injection amount and the second nitrogen oxide concentration according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first deterioration factor, and the first ammonia storage value.

[0195] Optionally, in the control device, the third determination unit includes:

[0196] A first determination subunit, configured to, when the target mode is a regeneration mode, acquire a first regeneration deterioration factor of the front-stage SCR, and determine a fifth deterioration factor according to the first deterioration factor and the first regeneration deterioration factor;

[0197] A second determination subunit, configured to, when the target mode is a normal mode or a PN reduction mode, determine the first deterioration factor as the fifth deterioration factor;

[0198] A third determination subunit, configured to determine the first urea injection amount according to the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first ammonia storage value, and the fifth deterioration factor.

[0199] Optionally, in the control device, a second determination subunit is specifically configured to obtain the first regeneration cycle number of the pre-stage SCR, and determine the first regeneration deterioration factor according to the first regeneration cycle number.

[0200] Optionally, in the control device, the second determination module 83 includes:

[0201] A fourth determination unit, configured to obtain the second regeneration deterioration factor of the post-stage SCR when the target mode is the regeneration mode, and determine the sixth deterioration factor according to the second deterioration factor and the second regeneration deterioration factor;

[0202] A fifth determination unit, configured to determine the second deterioration factor as the sixth deterioration factor when the target mode is the normal mode or the PN reduction mode;

[0203] A sixth determination unit, configured to determine the second ammonia storage value of the post-stage SCR according to the second temperature value and the second nitrogen oxide concentration;

[0204] A seventh determination unit, configured to determine the reference efficiency of the post-stage SCR according to the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value;

[0205] An eighth determination unit, configured to obtain the efficiency correction coefficient of the post-stage SCR when the target mode is the PN reduction mode, and determine the second target efficiency of the post-stage SCR according to the reference efficiency and the efficiency correction coefficient;

[0206] A ninth determination unit, configured to determine the reference efficiency as the second target efficiency of the post-stage SCR when the target mode is the regeneration mode or the normal mode;

[0207] A tenth determination unit, configured to determine the second urea injection amount of the post-stage SCR according to the second target efficiency, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth deterioration factor, and the second ammonia storage value.

[0208] Optionally, in the control device, a fourth determination subunit is specifically configured to obtain the second regeneration cycle number of the post-stage SCR, and determine the second regeneration deterioration factor according to the first regeneration cycle number.

[0209] Optionally, in the control device, the sixth determination unit is specifically configured to determine the efficiency correction coefficient according to the first target efficiency and the first temperature value.

[0210] Optionally, in the control device, the acquisition module 81 includes:

[0211] The first acquisition unit is configured to acquire a third deterioration factor of the pre-stage SCR and a first operating mileage of the pre-stage SCR in each deterioration temperature range during the current calculation cycle; the third deterioration factor is the deterioration factor of the pre-stage SCR after the previous calculation cycle;

[0212] The first calculation unit is configured to determine the first deterioration factor according to the third deterioration factor and the first operating mileage corresponding to each deterioration temperature range;

[0213] The first acquisition unit is configured to acquire a fourth deterioration factor of the post-stage SCR and a second operating mileage of the post-stage SCR in each deterioration temperature range during the current calculation cycle; the fourth deterioration factor is the deterioration factor of the post-stage SCR after the previous calculation cycle;

[0214] The second calculation unit is configured to determine the second deterioration factor according to the fourth deterioration factor and the second operating mileage corresponding to each deterioration temperature range.

[0215] Optionally, in the control device, the third determination unit further includes:

[0216] The first execution subunit is configured to execute the step of acquiring the first regeneration deterioration factor of the pre-stage SCR before acquiring the regeneration deterioration factor of the pre-stage SCR, when the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold.

[0217] Optionally, in the control device, the fourth determination unit further includes:

[0218] The second execution subunit is configured to execute the step of acquiring the second regeneration deterioration factor of the post-stage SCR before acquiring the second regeneration deterioration factor of the post-stage SCR, when the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold.

[0219] An embodiment of the present invention further provides a vehicle, which includes a dual-stage SCR aftertreatment system and also includes the urea injection control device as described above.

[0220] For the above-described apparatus and vehicle embodiments, since they are basically similar to the urea injection control method embodiments, reference may be made to the partial descriptions of the method embodiments for the relevant parts.

[0221] The urea injection control device provided by the embodiments of the present invention determines the urea injection amount matched to this stage of SCR respectively based on the target mode enabled by the engine, the temperature value at the inlet, the exhaust gas flow rate, the nitrogen oxide concentration, and the degradation factor. It can, on the premise of meeting the emission standards, timely match the operation mode requirements of the engine and the actual treatment capacity of the selective catalytic reduction converter, reduce the after-treatment cost, and extend the service life of the after-treatment system, thereby effectively improving the comprehensive treatment effect of the two-stage SCR after-treatment system on nitrogen oxides.

[0222] The embodiments of the present invention also provide an electronic device, as Figure 9 shown, including a processor 901, a communication interface 902, a memory 903, and a communication bus 904. Among them, the processor 901, the communication interface 902, and the memory 903 communicate with each other through the communication bus 904.

[0223] The memory 903 is used to store a computer program.

[0224] When the processor 901 is used to execute the program stored on the memory 903, the following steps are implemented:

[0225] Obtain a first temperature value, an exhaust gas flow rate, a first nitrogen oxide concentration, and a first degradation factor at the inlet of the front-stage SCR in the two-stage SCR treatment system, and obtain a second temperature value and a second degradation factor at the inlet of the rear-stage SCR in the two-stage SCR treatment system, and obtain the target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode, or a normal mode;

[0226] Determine a first target efficiency, a first urea injection amount, and a second nitrogen oxide concentration at the outlet of the front-stage SCR according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first degradation factor;

[0227] Determine a second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor;

[0228] Control the urea nozzle of the front-stage SCR to perform urea injection according to the first urea injection amount, and control the urea nozzle of the rear-stage SCR to perform urea injection according to the second urea injection amount.

[0229] Among them, the processor 901 can also implement other steps in the above urea injection control method, which will not be elaborated here.

[0230] The communication bus mentioned in the above electronic device can be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, only a thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0231] The communication interface is used for communication between the above electronic device and other devices.

[0232] The memory can include a Random Access Memory (RAM), and can also include a non-volatile memory, such as at least one disk memory. Optionally, the memory can also be at least one storage device located far from the aforementioned processor.

[0233] The above-mentioned processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0234] In another embodiment provided by the present invention, a computer-readable storage medium is also provided. Instructions are stored in this computer-readable storage medium. When it runs on a computer, it causes the computer to execute the urea injection control method described in the above embodiment.

[0235] In another embodiment provided by the present invention, a computer program product containing instructions is also provided. When it runs on a computer, it causes the computer to execute the urea injection control method described in the above embodiment.

[0236] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD)).

[0237] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is 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 expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0238] Each embodiment in this specification is described in a related manner. The same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. For the embodiments of the device, electronic device, computer-readable storage medium, and computer program product including instructions, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments.

[0239] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A urea injection control method, characterized in that, Applied to a two-stage SCR aftertreatment system, the method includes: Obtaining a first temperature value, an exhaust gas flow rate, a first nitrogen oxide concentration, and a first degradation factor at the inlet of the front-stage SCR in the two-stage SCR treatment system, and obtaining a second temperature value, a second degradation factor at the inlet of the rear-stage SCR in the two-stage SCR treatment system, and obtaining a target mode enabled by the engine, where the target mode is a regeneration mode, a PN reduction mode, or a normal mode; Determining a first urea injection amount of the front-stage SCR and a second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first degradation factor; Determining a second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor; Controlling the urea nozzle of the front-stage SCR to inject urea according to the first urea injection amount, and controlling the urea nozzle of the rear-stage SCR to inject urea according to the second urea injection amount.

2. The control method according to claim 1, wherein Determining the first urea injection amount of the front-stage SCR and the second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the front nitrogen oxide concentration, and the first degradation factor, including: Determining a first ammonia storage value of the front-stage SCR according to the first temperature value and the first nitrogen oxide concentration; Determining a first target efficiency of the front-stage SCR according to the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value; Determining the first urea injection amount and the second nitrogen oxide concentration according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value.

3. The control method according to claim 2, wherein Determining the first urea injection amount according to the target mode, the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first degradation factor, and the first ammonia storage value, including: When the target mode is the regeneration mode, obtaining a first regeneration degradation factor of the front-stage SCR, and determining a fifth degradation factor according to the first degradation factor and the first regeneration degradation factor; When the target mode is the normal mode or the PN reduction mode, determining the first degradation factor as the fifth degradation factor; Determining the first urea injection amount according to the first target efficiency, the exhaust gas flow rate, the first nitrogen oxide concentration, the first ammonia storage value, and the fifth degradation factor.

4. The control method according to claim 3, characterized in that Determining the second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second degradation factor, including: When the target mode is the regeneration mode, obtaining a second regeneration degradation factor of the rear-stage SCR, and determining a sixth degradation factor according to the second degradation factor and the second regeneration degradation factor; When the target mode is the normal mode or the PN reduction mode, determining the second degradation factor as the sixth degradation factor; Determine the second ammonia storage value of the post-stage SCR according to the second temperature value and the second nitrogen oxide concentration; Determine the reference efficiency of the post-stage SCR according to the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth degradation factor and the second ammonia storage value; When the target mode is the PN reduction mode, obtain the efficiency correction coefficient of the post-stage SCR, and determine the second target efficiency of the post-stage SCR according to the reference efficiency and the efficiency correction coefficient; When the target mode is the regeneration mode or the normal mode, determine the reference efficiency as the second target efficiency of the post-stage SCR; Determine the second urea injection amount of the post-stage SCR according to the second target efficiency, the exhaust gas flow rate, the second nitrogen oxide concentration, the sixth degradation factor and the second ammonia storage value; 5. The control method according to claim 4, wherein Obtain the first regeneration degradation factor of the pre-stage SCR, including: Obtain the first regeneration cycle number of the pre-stage SCR, and determine the first regeneration degradation factor according to the first regeneration cycle number; Obtain the second regeneration degradation factor of the post-stage SCR, including: Obtain the second regeneration cycle number of the post-stage SCR, and determine the second regeneration degradation factor according to the second regeneration cycle number; 6. The control method according to claim 4, wherein Obtain the efficiency correction coefficient of the post-stage SCR, including: Determine the efficiency correction coefficient according to the first target efficiency and the first temperature value; 7. The control method according to claim 1, wherein The obtaining of the first degradation factor includes: Obtain the third degradation factor of the pre-stage SCR and the first operating mileage of the pre-stage SCR in each degradation temperature range in the current calculation period; the third degradation factor is the degradation factor of the pre-stage SCR after the previous calculation period; Determine the first degradation factor according to the third degradation factor and the first operating mileage corresponding to each degradation temperature range; The obtaining of the second degradation factor includes: Obtain the fourth degradation factor of the post-stage SCR and the second operating mileage of the post-stage SCR in each degradation temperature range in the current calculation period; the fourth degradation factor is the degradation factor of the post-stage SCR after the previous calculation period; Determine the second degradation factor according to the fourth degradation factor and the second operating mileage corresponding to each degradation temperature range; 8. The control method according to claim 4, wherein Before obtaining the first regeneration degradation factor of the pre-stage SCR, it further includes: When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, perform the step of obtaining the first regeneration degradation factor of the pre-stage SCR; Before obtaining the second regeneration degradation factor of the post-stage SCR, it further includes: When the exhaust gas flow rate is greater than or equal to the flow rate threshold, the engine speed is greater than or equal to the speed threshold, the vehicle speed is greater than or equal to the vehicle speed threshold, the second temperature is greater than or equal to the temperature threshold, and the second nitrogen oxide concentration is less than the concentration threshold, perform the step of obtaining the second regeneration degradation factor of the post-stage SCR.

9. A urea injection control device, characterized in that, Applied to a two-stage SCR aftertreatment system, the device includes: An acquisition module for acquiring a first temperature value, an exhaust gas flow rate, a first nitrogen oxide concentration, and a first deterioration factor at the inlet of the front-stage SCR in the two-stage SCR treatment system, and acquiring a second temperature value, a second deterioration factor at the inlet of the rear-stage SCR in the two-stage SCR treatment system, and acquiring a target mode enabled by the engine, the target mode being a regeneration mode, a PN reduction mode, or a normal mode; A first determination module for determining a first urea injection amount of the front-stage SCR and a second nitrogen oxide concentration at the outlet according to the target mode, the first temperature value, the exhaust gas flow rate, the first nitrogen oxide concentration, and the first deterioration factor; A second determination module for determining a second urea injection amount of the rear-stage SCR according to the target mode, the second temperature value, the exhaust gas flow rate, the second nitrogen oxide concentration, and the second deterioration factor; An injection control module for controlling the urea nozzle of the front-stage SCR to inject urea according to the first urea injection amount, and controlling the urea nozzle of the rear-stage SCR to inject urea according to the second urea injection amount.

10. A vehicle, characterized in that, Comprising a two-stage SCR aftertreatment system, further comprising the control device as claimed in claim 9.

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