Method and device for correcting urea injection amount, storage medium and electronic device

Abstract

The application provides a urea injection amount correction method and device, a storage medium and an electronic device. The method comprises the following steps: obtaining a plurality of first cumulative values and a plurality of second cumulative values, the first cumulative value being a cumulative value of work done by the engine in a first preset time period, and the second cumulative value being a cumulative value of NOx unit emission mass in the first preset time period, the NOx unit emission mass being the mass of NOx in exhaust gas discharged by the downstream of the SCR in a unit time; obtaining a plurality of engine specific emission values, one specific emission value being a ratio of the corresponding first cumulative value to the second cumulative value; determining an average specific emission value of all the specific emission values as an average specific emission, and correcting an initial urea injection amount according to a ratio of the average specific emission to a specific emission threshold to determine a target urea injection amount. The method calculates the specific emission based on the actual work done by the engine, adjusts the urea injection amount within the maximum allowable specific emission of the engine, reduces the urea injection, and reduces the operating cost.

Description

Technical Field

[0001] This application relates to the field of engine urea injection quantity correction, and more specifically, to a method for correcting urea injection quantity, a device for correcting urea injection quantity, a computer-readable storage medium, and an electronic device. Background Technology

[0002] To meet the emission requirements of heavy-duty diesel engines, a selective catalytic converter (SCR) is typically added to the aftertreatment system. The SCR injects urea based on the amount of NOx in the vehicle's exhaust and its own reaction efficiency to reduce the NOx content to within the required range. However, when the vehicle operates under relatively stable conditions (high-speed conditions), the amount of NOx produced by the engine itself is less; in this case, the urea injection amount calculated using the above method will result in significant urea waste (due to the difference between the actual injection and the specified requirements). Summary of the Invention

[0003] The main objective of this application is to provide a method for correcting urea injection quantity, a device for correcting urea injection quantity, a computer-readable storage medium, and an electronic device, so as to at least solve the problem that the calculation method for urea injection quantity in existing engines is not accurate enough, resulting in excessive urea injection and waste of resources.

[0004] To achieve the above objectives, according to one aspect of this application, a method for correcting urea injection quantity is provided, comprising: acquiring a plurality of first cumulative values ​​and a plurality of second cumulative values, wherein the first cumulative value is the cumulative value of work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period, wherein the NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted downstream of the SCR per unit time, and the first cumulative value and the second cumulative value correspond one-to-one; acquiring a plurality of specific emission values ​​of the engine, wherein one of the specific emission values ​​is the ratio of the corresponding first cumulative value to the second cumulative value; determining the average value of all the specific emission values ​​as the average specific emission, and correcting the initial urea injection quantity according to the ratio of the average specific emission to a specific emission threshold to determine the target urea injection quantity, wherein the specific emission threshold is the maximum permissible specific emission value of the engine.

[0005] Optionally, the initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity, including: correcting the initial adjustment coefficient using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, wherein the first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR, and the initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold; processing the corrected adjustment coefficient using a moving average method to obtain a target adjustment coefficient; and correcting the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity, wherein the target urea injection quantity is the product of the target adjustment coefficient and the initial urea injection quantity.

[0006] Optionally, the initial adjustment coefficient is corrected using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, including: obtaining a first MAP table and a second MAP table, wherein the first MAP table is used to characterize the relationship between the engine coolant temperature and the first correction coefficient, and the second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient; obtaining the engine coolant temperature and the downstream temperature of the SCR at the current time; determining the first correction coefficient based on the first MAP table and the engine coolant temperature at the current time; determining the second correction coefficient based on the second MAP table and the downstream temperature of the SCR at the current time; and correcting the initial adjustment coefficient using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, wherein the corrected adjustment coefficient is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

[0007] Optionally, after processing the modified adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity, the method further includes: obtaining the widest range of the coefficient, wherein the widest range of the coefficient is a preset widest numerical range of the target adjustment coefficient; and resetting the calculation parameters of the engine if the target adjustment coefficient is not within the widest range of the coefficient, wherein the calculation parameters of the engine include at least: the first cumulative value, the second cumulative value, the specific emission value of the engine, the average specific emission, and the target adjustment coefficient.

[0008] Optionally, acquiring multiple first cumulative values ​​and multiple second cumulative values ​​includes: acquiring the engine's operating parameters, which include: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening, and brake pedal opening, wherein the engine is installed in the vehicle; and acquiring the first cumulative value and the second cumulative value when the engine's operating parameters meet a first preset condition, wherein the first preset condition includes: the engine coolant temperature is greater than or equal to a first temperature, the upstream temperature of the SCR is greater than or equal to a second temperature, the vehicle speed is within a first threshold range, the accelerator pedal opening is within a first opening range, and the brake pedal opening is within a second opening range.

[0009] Optionally, in the process of acquiring multiple first cumulative values ​​and multiple second cumulative values, the method further includes: stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine operating parameters meet a second preset condition, wherein the second preset condition includes at least one of the following: the engine coolant temperature is lower than the first temperature, the upstream temperature of the SCR is lower than the second temperature, the vehicle speed is not within the first threshold range, the accelerator pedal opening is not within the first opening range, and the brake pedal opening is not within the second opening range.

[0010] Optionally, after stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, the method further includes: obtaining an offset duration, the offset duration being the duration during which the engine's operating parameters meet the second preset condition; resetting the first cumulative value and the second cumulative value when the offset duration is greater than or equal to the second preset duration; and continuing to calculate the currently calculated first cumulative value and the currently calculated second cumulative value when the offset duration is less than the second preset duration and the engine's operating parameters meet the first preset condition.

[0011] According to another aspect of this application, a urea injection quantity correction device is provided, comprising: a first acquisition unit, configured to acquire a plurality of first cumulative values ​​and a plurality of second cumulative values, wherein the first cumulative values ​​are the cumulative value of work done by the engine within a first preset time period, and the second cumulative values ​​are the cumulative value of NOx emission mass per unit mass within the first preset time period, wherein the NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted downstream of the SCR per unit time, and the first cumulative values ​​and the second cumulative values ​​correspond one-to-one; a second acquisition unit, configured to acquire a plurality of specific emission values ​​of the engine, wherein one of the specific emission values ​​is the ratio of the corresponding first cumulative value to the second cumulative value; and a determination unit, configured to determine the average value of all the specific emission values ​​as the average specific emission, and correct the initial urea injection quantity according to the ratio of the average specific emission to a specific emission threshold to determine the target urea injection quantity, wherein the specific emission threshold is the maximum permissible specific emission value of the engine.

[0012] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform any of the aforementioned urea injection quantity correction methods.

[0013] According to another aspect of this application, an electronic device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including a method for performing any of the urea injection quantity correction methods described above.

[0014] Applying the technical solution of this application, the above-mentioned method for correcting urea injection quantity first obtains multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission per unit mass within the first preset time period. The first cumulative value corresponds one-to-one with the second cumulative value. Then, multiple engine specific emission values ​​are obtained, where each specific emission value is the ratio of the corresponding first cumulative value to the second cumulative value. Finally, the average value of all specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. The specific emission threshold is the engine's maximum permissible specific emission value. This method calculates specific emissions based on the engine's actual work output, adjusts the urea injection quantity within the engine's maximum permissible specific emission, reduces urea injection, lowers operating costs, and solves the problem of low accuracy in existing engine urea injection quantity calculation methods, leading to excessive urea injection and resource waste. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 A hardware structure block diagram of a mobile terminal for performing a method for correcting urea injection volume according to an embodiment of this application is shown.

[0017] Figure 2 A schematic flowchart of a method for correcting urea injection volume according to an embodiment of this application is shown.

[0018] Figure 3 A schematic diagram of a urea injection quantity correction system according to an embodiment of this application is shown;

[0019] Figure 4 A schematic flowchart of another method for correcting urea injection volume according to an embodiment of this application is shown;

[0020] Figure 5 A schematic flowchart of another method for correcting urea injection volume according to an embodiment of this application is shown;

[0021] Figure 6 A structural block diagram of a urea injection quantity correction device provided according to an embodiment of this application is shown.

[0022] The above figures include the following reference numerals:

[0023] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0028] Selective Catalytic Reduction (SCR) is a device that treats NOx emissions from diesel vehicles. With the aid of a catalyst, ammonia or urea is injected as a reducing agent to reduce NOx in the exhaust gas into N2 and H2O.

[0029] Nitrogen oxides: abbreviated as NOx, including nitric oxide (NO) and nitrogen dioxide (NO2) in automobile exhaust;

[0030] Specific emissions: The mass of pollutants emitted per unit of output power per unit of time;

[0031] Diesel oxidation catalyst (DOC)

[0032] Diesel Particulate Filter (DPF): Also known as a diesel particulate regenerator, it is a device used to reduce particulate pollutant emissions in exhaust gas.

[0033] Ammonia Slip Catalyst (ASC) is a device used to reduce ammonia leakage in the exhaust gas after SCR through catalytic oxidation.

[0034] As described in the background section, existing SCRs inject urea based on the amount of NOx in vehicle exhaust and their own reaction efficiency to reduce the NOx content in the exhaust to the required range. However, when the vehicle is operating under relatively stable conditions (high-speed conditions), the amount of NOx produced by the engine itself is relatively small. In this case, the urea injection amount calculated by the above method will result in a lot of urea waste (due to the gap between the actual injection and the specified requirements). To solve the problem that the calculation method of urea injection amount of existing engines has low accuracy, resulting in excessive urea injection and resource waste, the embodiments of this application provide a method for correcting the amount of urea injection, a device for correcting the amount of urea injection, a computer-readable storage medium, and an electronic device.

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a urea injection quantity correction method according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0037] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the urea injection quantity correction method in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory and non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the aforementioned networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0038] This embodiment provides a method for correcting the amount of urea injection that runs on a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0039] Figure 2 This is a flowchart of a method for correcting the urea injection volume according to an embodiment of this application. Figure 2 As shown, the method includes the following steps:

[0040] Step S201: Obtain multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one.

[0041] Specifically, in existing technologies, to meet emission requirements for heavy-duty diesel engine exhaust, a Selective Catalytic Reduction (SCR) device is typically added to the aftertreatment system. The SCR injects urea based on the amount of NOx in the vehicle exhaust and its own reaction efficiency to reduce the NOx content in the exhaust to within the required range. However, when the vehicle operates under relatively stable conditions (high-speed conditions), the amount of NOx produced by the engine itself is relatively small. In this case, the urea injection amount calculated using the above method will result in significant urea waste (due to the difference between actual injection and regulatory requirements). The above embodiment can ensure that the urea injection amount is reduced as much as possible while meeting the emission requirements to avoid resource waste.

[0042] Selective catalytic reduction (SCR) is an aftertreatment system. Its technical principle is to selectively reduce nitrogen oxides (NOx) to nitrogen and water in an oxygen-rich environment using a reducing agent, under the action of a catalyst. Diesel engine SCR exhaust aftertreatment aims to effectively control emissions of carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) in exhaust gases to meet legal and regulatory requirements. Finally, the high levels of NOx in the engine exhaust are treated by a special onboard aftertreatment system. This exhaust gas treatment strategy works by optimizing the combustion process in the diesel engine cylinders to effectively control emissions of carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) in the combustion exhaust, meeting legal and regulatory requirements. Finally, the high levels of NOx in the engine exhaust are treated by a special onboard aftertreatment system to meet legal and regulatory requirements. During the aftertreatment process, the dosing unit accurately injects the appropriate amount of urea into the exhaust pipe according to instructions from the engine control unit (ECU). The ammonia and nitrogen oxides produced by the decomposition of urea undergo a catalytic reduction reaction in the catalytic converter, ultimately generating harmless nitrogen (N2) and water (H2O). According to measurements, the NOx conversion rate in the SCR exhaust aftertreatment system can typically reach over 60%.

[0043] The above method is applied to, for example Figure 3In the urea injection quantity correction system shown, the second cumulative value is the mass of NOx emitted in the exhaust gas per unit time detected by NOx2 (downstream NOx sensor of ASC). The urea injection quantity correction system consists of a controller, engine, DOC, DPF, SCR, and ASC. Tus is the upstream temperature sensor of SCR, NOx1 is the upstream NOx sensor of SCR, DM is the urea injector, Tds is the downstream temperature sensor of SCR, and NOx2 is the downstream NOx sensor of ASC. The first preset duration can be a functional release window period, which can be 10 seconds. That is, a first cumulative value is the cumulative work done by the engine within a functional release window period, and a second cumulative value is the cumulative mass of NOx emitted per unit of exhaust gas within a functional release window period. The unit of the first cumulative value is kWh, which is the total work done by the engine within a functional release window period, and the unit of the second cumulative value is g, which is the total mass of NOx emitted per unit of exhaust gas within a functional release window period.

[0044] In practical applications, the aforementioned urea injection quantity correction method can be triggered by the vehicle driver, specifically through a hardware switch or screen in the driver's cab. That is, the correction method is initiated when the driver presses the hardware switch button or touches the correction trigger indicator on the control screen. The number of the first and second cumulative values ​​is pre-defined and can be 1000.

[0045] The specific implementation steps for obtaining multiple first cumulative values ​​and multiple second cumulative values ​​are as follows:

[0046] Step S2011: Obtain the operating parameters of the engine, including: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening and brake pedal opening of the vehicle, wherein the engine is installed in the vehicle.

[0047] Step S2012: When the operating parameters of the engine meet the first preset conditions, the first cumulative value and the second cumulative value are obtained. The first preset conditions include: the engine coolant temperature is greater than or equal to the first temperature, the upstream temperature of the SCR is greater than or equal to the second temperature, the vehicle speed is within the first threshold range, the accelerator pedal opening is within the first opening range, and the brake pedal opening is within the second opening range.

[0048] Specifically, based on the engine's operating parameters, it is possible to accurately determine whether the engine is currently in a stable operating condition, thereby accurately determining the time to obtain the first and second cumulative values. This lays the foundation for subsequent steps, accurately obtaining the average emission ratio under stable engine conditions, thus obtaining an accurate correction coefficient. Based on this, the urea injection quantity is corrected, resulting in an accurate urea injection quantity under stable operating conditions.

[0049] like Figure 3 The urea injection rate correction system shown above has an upstream temperature of [temperature value missing] for the SCR. Figure 3 The temperature value is detected by the TUS (upstream temperature sensor of SCR). The first temperature can be set to 100℃, and the second temperature can be set to 180℃. The first opening range can be set to 40°-50°, and the second opening range can also be set to 40°-50°. This means that if the accelerator pedal opening or brake pedal opening is too large or too small, the vehicle is considered not to be in a stable operating condition. When the engine operating parameters meet the first preset condition, it proves that the vehicle has entered a stable operating condition mode. At this time, the aforementioned function window release period (i.e., the first preset time starts counting) begins, and the first and second cumulative values ​​are acquired. The stable operating condition can be a high-speed or high-temperature after-treatment operating period.

[0050] In addition, the engine operating parameters are not limited to those listed in the above embodiments. In actual situations, the engine operating condition can also be determined based on the values ​​of other engine operating parameters.

[0051] In the process of acquiring multiple first cumulative values ​​and multiple second cumulative values, the above method further includes the following steps: when the operating parameters of the engine meet the second preset conditions, stop calculating the currently calculated first cumulative value and the currently calculated second cumulative value. The second preset conditions include at least one of the following: the engine coolant temperature is lower than the first temperature, the upstream temperature of the SCR is lower than the second temperature, the vehicle speed is not within the first threshold range, the accelerator pedal opening is not within the first opening range, and the brake pedal opening is not within the second opening range.

[0052] Specifically, when the engine operating parameters meet the second preset condition, it is proven that the vehicle is no longer in a stable operating condition mode. At this time, the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value is stopped. This can avoid the first and second cumulative values ​​being affected by the parameters that the vehicle is not in a stable operating condition mode, and ensure that the first and second cumulative values ​​are obtained under stable operating conditions, thus guaranteeing the accuracy of the first and second cumulative values.

[0053] Wherein, after stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, the method further includes the following steps:

[0054] Step S301: Obtain the offset duration, where the offset duration is the duration during which the engine's operating parameters satisfy the second preset condition.

[0055] Step S302: If the offset duration is greater than or equal to the second preset duration, reset the first cumulative value and the second cumulative value.

[0056] Step S303: If the offset duration is less than the second preset duration and the engine operating parameters meet the first preset condition, continue to calculate the currently calculated first cumulative value and the currently calculated second cumulative value.

[0057] Specifically, by monitoring the offset duration, the cause of the engine's operating parameter deviation can be determined. If the offset duration is less than the second preset duration, it may be due to a signal error from the sensor or a short-term deviation in the engine's operating parameters caused by external factors. However, the vehicle will quickly return to stable operation. Therefore, the first and second cumulative values ​​can be calculated again after the vehicle returns to stable operation without significantly affecting subsequent steps. However, if the offset duration is greater than or equal to the second preset duration, it is considered that the vehicle cannot return to stable operation in a short time. The first and second cumulative values ​​within this window are then reset, and the previously calculated first and second cumulative values ​​within this window are considered invalid. This ensures the accuracy of the first and second cumulative values ​​and prevents them from being affected by parameters outside the vehicle's stable operating mode, ensuring that both the first and second cumulative values ​​are obtained under stable operating conditions. The second preset duration can be 5 seconds, 10 seconds, etc., and can also track whether the window pause time is too long. If it is, the calculated value of this paused window is invalidated to prevent excessively long window intervals.

[0058] Step S202: Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the first cumulative value to the second cumulative value.

[0059] Specifically, the regulations limiting NOx emissions from exhaust gases are based on engine specific emissions. This means that NOx emissions are limited by setting limits on the engine's specific emissions. Generally, the limit for NOx emissions from exhaust gases is 0.25 g / kWh. The unit for engine specific emissions is g / kWh, meaning the mass of NOx emitted per kWh of cumulative power output is the engine's specific emissions at the current moment. The mass of NOx is calculated based on the NOx concentration.

[0060] Step S203: The average value of all the above-mentioned specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the above-mentioned average specific emission to the specific emission threshold to determine the target urea injection quantity. The above-mentioned specific emission threshold is the maximum permissible specific emission value of the above-mentioned engine.

[0061] Specifically, the initial urea injection quantity is a pre-set quantity that ensures the NOx emissions from the engine under any operating condition do not exceed the prescribed limits. The initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. This correction can be performed using multiplication; that is, the target urea injection quantity is the product of the initial urea injection quantity and the ratio of the average specific emission to the specific emission threshold. In practical applications, besides multiplication, other correction methods can also be used to correct the initial urea injection quantity. Correcting the initial urea injection quantity solely based on the ratio of the average specific emission to the specific emission threshold results in low accuracy for the target urea injection quantity. Therefore, the ratio of the average specific emission to the specific emission threshold is pre-corrected to obtain a more accurate correction coefficient. This more accurate correction coefficient is then used to correct the initial urea injection quantity to determine the target urea injection quantity.

[0062] The average specific emission is calculated by taking the specific emission values ​​obtained from multiple historical operating conditions of the engine, which lays the foundation for subsequent calculation steps. Within the specified limits, the urea injection quantity is intelligently adjusted to reduce urea injection and lower operating costs for users.

[0063] Among them, such as Figure 4 As shown, the specific implementation steps for determining the target urea injection amount by correcting the initial urea injection amount based on the ratio of the average specific emission to the specific emission threshold are as follows:

[0064] Step S401: The initial adjustment coefficient is corrected using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient. The first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, and the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR. The initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold.

[0065] The specific steps for correcting the initial adjustment coefficient using the first and second correction coefficients to obtain the corrected adjustment coefficient are as follows:

[0066] Step S4011: Obtain a first MAP table and a second MAP table. The first MAP table is used to characterize the relationship between the engine water temperature and the first correction coefficient, and the second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient.

[0067] Step S4012: Obtain the engine water temperature and the downstream temperature of the SCR at the current moment.

[0068] Step S4013: Determine the first correction coefficient based on the first MAP table and the engine coolant temperature at the current moment;

[0069] Step S4014: Determine the second correction coefficient based on the second MAP table and the downstream temperature of the SCR at the current time.

[0070] Step S4015: The initial adjustment coefficient is corrected using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, which is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

[0071] Specifically, for the above embodiments, this allows for a more accurate correction adjustment coefficient. Based on this correction adjustment coefficient, a data foundation is provided for subsequent steps to obtain a more accurate target adjustment coefficient, thereby correcting the initial urea injection quantity and obtaining a more accurate target urea injection quantity. Engine water temperature refers to the temperature of the engine coolant. The first and second MAP tables are calibration MAP tables, obtained by the developers through testing on an engine bench.

[0072] Step S402: The above-mentioned modified adjustment coefficient is processed using the moving average method to obtain the target adjustment coefficient;

[0073] Specifically, this allows for a more accurate target adjustment coefficient to correct the initial urea injection quantity, resulting in a more precise target urea injection quantity. Engine specific emissions are calculated based on a cyclic window, and a stable specific emission value is calculated using a filter to obtain a reliable adjustment coefficient, providing a data foundation for reducing urea injection quantity.

[0074] The method further includes the following steps: after processing the above-mentioned modified adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the above-mentioned target adjustment coefficient to determine the above-mentioned target urea injection quantity:

[0075] Step S501: Obtain the widest range of coefficients, where the widest range of coefficients is the preset widest numerical range of the target adjustment coefficients.

[0076] Step S502: If the target adjustment coefficient is not within the widest range of the coefficient, reset the calculation parameters of the engine. The calculation parameters of the engine include at least: the first cumulative value, the second cumulative value, the specific emission value of the engine, the average specific emission, and the target adjustment coefficient.

[0077] Step S503: The initial urea injection quantity is corrected using the target adjustment coefficient to determine the target urea injection quantity, which is the product of the target adjustment coefficient and the initial urea injection quantity.

[0078] Specifically, this avoids overshoot caused by the integrator. By setting a threshold range for the urea injection adjustment coefficient, it prevents the urea injection quantity adjustment from going out of control due to integral overflow or incorrect operating condition identification. The integrator is then reset to 0, and other parameters are reset accordingly.

[0079] The urea injection quantity correction method of this application first obtains multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission per unit mass within the first preset time period. The first cumulative value corresponds one-to-one with the second cumulative value. Then, multiple engine specific emission values ​​are obtained, where each specific emission value is the ratio of the corresponding first cumulative value to the second cumulative value. Finally, the average value of all specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. The specific emission threshold is the engine's maximum permissible specific emission value. This method calculates specific emissions based on the engine's actual work output, adjusts the urea injection quantity within the engine's maximum permissible specific emission, reduces urea injection, lowers operating costs, and solves the problem of low accuracy in existing engine urea injection quantity calculation methods, leading to excessive urea injection and resource waste.

[0080] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the urea injection quantity correction method of this application will be described in detail below with reference to specific embodiments.

[0081] This embodiment relates to a specific method for correcting the urea injection volume, such as... Figure 5 As shown, it includes the following steps:

[0082] Step S1: First, the driver activates the correction function via a hardware switch or screen in the driver's cab. Then, it checks whether the engine coolant temperature and the upstream temperature of the SCR exceed the threshold, and whether the vehicle speed, accelerator pedal opening, and brake pedal opening are within the threshold range. When all parameters meet the requirements, the function release window is considered to have been entered. If any parameter is not met, it indicates that the conditions for calculation are not met at this time.

[0083] Step S2: After entering the function release window, integrate the engine power and the downstream NOx mass of SCR respectively. When the integral value of engine power reaches the threshold, calculate the engine specific emission value. After the calculation is completed, reset each integrator and perform the next window specific emission calculation.

[0084] Step S3: If any parameter of the engine coolant temperature, the upstream temperature of the SCR, the vehicle speed, the accelerator pedal, or the brake pedal exceeds the threshold within the window period, the time of exceeding the threshold is recorded. If the time exceeds the threshold T1 (i.e., the time is too long), the calculated value within the window period is considered invalid, the integral value is reset, and the specific emissions calculated in that window are discarded. After a calibrated number of windows, the average specific emissions are obtained.

[0085] Step S4: Based on the engine emission ratio and the specified limits, the initial adjustment coefficient F is initially obtained. bas The adjustment coefficient F is obtained after correction for engine coolant temperature and SCR upstream temperature. cor The target adjustment coefficient F is then obtained after moving average. ac To avoid overshoot caused by the integrator, a threshold range is set for the final adjustment coefficient. ac If the threshold is exceeded, the scheme is considered to have overshooted, and all integrators and adjustment coefficients need to be reset.

[0086] Step S5: Multiply the calculated final adjustment coefficient by the original urea injection amount to obtain the final urea injection amount, which is then sprayed out through the urea injection system.

[0087] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0088] This application also provides a urea injection quantity correction device. It should be noted that the urea injection quantity correction device of this application embodiment can be used to execute the urea injection quantity correction method provided in this application embodiment. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0089] The following describes the urea injection quantity correction device provided in the embodiments of this application.

[0090] Figure 6 This is a schematic diagram of a urea injection quantity correction device according to an embodiment of this application. Figure 6 As shown, the device includes a first acquisition unit 10, a second acquisition unit 20, and a determination unit 30. The first acquisition unit 10 is used to acquire multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission per unit mass within the first preset time period. The NOx emission per unit mass is the mass of NOx in the exhaust gas emitted downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one. The second acquisition unit 20 is used to acquire multiple specific emission values ​​of the engine. One of the specific emission values ​​is the ratio of the corresponding first cumulative value to the second cumulative value. The determination unit 30 is used to determine the average of all the specific emission values ​​as the average specific emission, and to correct the initial urea injection amount according to the ratio of the average specific emission to the specific emission threshold to determine the target urea injection amount. The specific emission threshold is the maximum allowable specific emission value of the engine.

[0091] The urea injection quantity correction device of this application includes a first acquisition unit, a second acquisition unit, and a determination unit. The first acquisition unit is used to acquire multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission per unit mass within a first preset time period, where NOx per unit mass is the mass of NOx emitted in the exhaust gas downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one. The second acquisition unit is used to acquire multiple engine specific emission values, where one specific emission value is the ratio of the corresponding first cumulative value to the second cumulative value. The determination unit is used to determine the average of all specific emission values ​​as the average specific emission, and to correct the initial urea injection quantity based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. The specific emission threshold is the maximum allowable specific emission value of the engine. This device calculates the specific emission based on the actual work done by the engine, adjusts the urea injection quantity within the maximum allowable specific emission of the engine, reduces urea injection, lowers operating costs, and solves the problem that the existing calculation method for engine urea injection quantity has low accuracy, leading to excessive urea injection and resource waste.

[0092] In one optional example, the determining unit includes a first correction module, a first processing module, and a first determining module. The first correction module is used to correct the initial adjustment coefficient using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient. The first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, and the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR. The initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold. The first processing module is used to process the corrected adjustment coefficient using a moving average method to obtain a target adjustment coefficient. The first determining module is used to correct the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity. The target urea injection quantity is the product of the target adjustment coefficient and the initial urea injection quantity. This avoids overshoot caused by the integrator. By setting a threshold range for the urea injection adjustment coefficient, it prevents uncontrolled urea injection quantity adjustment due to integral overflow or incorrect operating condition identification. The integrator is reset to 0, and other parameters are reset accordingly.

[0093] In an optional example, the first correction module includes a first acquisition module, a second acquisition module, a second determination module, a third determination module, and a third correction module. The first acquisition module is used to acquire a first MAP table and a second MAP table. The first MAP table is used to characterize the relationship between the engine coolant temperature and the first correction coefficient, and the second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient. The second acquisition module is used to acquire the engine coolant temperature and the downstream temperature of the SCR at the current time. The second determination module is used to determine the first correction coefficient based on the first MAP table and the engine coolant temperature at the current time. The third determination module is used to determine the second correction coefficient based on the second MAP table and the downstream temperature of the SCR at the current time. The third correction module is used to correct the initial adjustment coefficient using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, which is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

[0094] For example, the above-mentioned device further includes a third acquisition module and a first reset module. The third acquisition module is used to acquire the widest range of the coefficient after processing the above-mentioned correction adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the above-mentioned target adjustment coefficient to determine the above-mentioned target urea injection quantity. The widest range of the coefficient is a preset widest numerical range of the above-mentioned target adjustment coefficient. The first reset module is used to reset the calculation parameters of the engine if the above-mentioned target adjustment coefficient is not within the widest range of the coefficient. The calculation parameters of the engine include at least: the above-mentioned first cumulative value, the above-mentioned second cumulative value, the engine's specific emission value, the above-mentioned average specific emission, and the above-mentioned target adjustment coefficient. A more accurate correction adjustment coefficient can be obtained, and based on the correction adjustment coefficient, a data basis can be provided for subsequent steps to obtain a more accurate target adjustment coefficient to correct the initial urea injection quantity and obtain a more accurate target urea injection quantity.

[0095] In this embodiment, the first acquisition unit includes a fourth acquisition module and a fifth acquisition module. The fourth acquisition module is used to acquire the operating parameters of the engine, including: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening, and brake pedal opening. The engine is installed in the vehicle. The fifth acquisition module is used to acquire the first cumulative value and the second cumulative value when the engine operating parameters meet the first preset conditions. The first preset conditions include: engine coolant temperature greater than or equal to a first temperature, upstream temperature of the SCR greater than or equal to a second temperature, vehicle speed within a first threshold range, accelerator pedal opening within a first opening range, and brake pedal opening within a second opening range. This allows for accurate determination of whether the engine's current operating condition is stable, thus accurately determining the time for acquiring the first and second cumulative values. This lays the foundation for subsequent steps, accurately obtaining the average emission ratio under stable engine operating conditions, thereby obtaining an accurate correction coefficient, and correcting the urea injection quantity accordingly to obtain an accurate urea injection quantity under stable operating conditions.

[0096] In an optional embodiment, the device further includes a second processing module. This second processing module, during the acquisition of multiple first and second cumulative values, stops calculating the currently being calculated first and second cumulative values ​​when the engine's operating parameters meet a second preset condition. The second preset condition includes at least one of the following: the engine coolant temperature is lower than the first temperature; the upstream temperature of the SCR is lower than the second temperature; the vehicle speed is not within the first threshold range; the accelerator pedal opening is not within the first opening range; and the brake pedal opening is not within the second opening range. This avoids the first and second cumulative values ​​being affected by parameters when the vehicle is not in a stable operating condition, ensuring that both the first and second cumulative values ​​are obtained under stable operating conditions, thus guaranteeing their accuracy.

[0097] As an optional solution, the above-mentioned device further includes a sixth acquisition module, a second reset module, and a calculation module. The sixth acquisition module is used to stop calculating the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, and then acquire an offset duration, which is the duration for which the engine's operating parameters meet the second preset condition. The second reset module is used to reset the first cumulative value and the second cumulative value when the offset duration is greater than or equal to the second preset duration. The calculation module is used to continue calculating the currently calculated first cumulative value and the currently calculated second cumulative value when the offset duration is less than the second preset duration and the engine's operating parameters meet the first preset condition. This avoids the first and second cumulative values ​​being affected by parameters when the vehicle is not in a stable operating condition, ensuring that both the first and second cumulative values ​​are obtained when the vehicle is in a stable operating condition.

[0098] The aforementioned urea injection volume correction device includes a processor and a memory. The first acquisition unit and other components are stored as program units in the memory, and the processor executes these program units to achieve the corresponding functions. All of the aforementioned modules are located in the same processor; alternatively, the modules may be located in different processors in any combination.

[0099] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured. By adjusting kernel parameters, the problem of low accuracy in calculating urea injection volume in existing engines, leading to excessive urea injection and wasted resources can be addressed.

[0100] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0101] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device containing the computer-readable storage medium to perform the urea injection quantity correction method.

[0102] Specifically, the methods for correcting the urea injection volume include:

[0103] Step S201: Obtain multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one.

[0104] Specifically, in existing technologies, to meet emission requirements for heavy-duty diesel engine exhaust, a Selective Catalytic Reduction (SCR) device is typically added to the aftertreatment system. The SCR injects urea based on the amount of NOx in the vehicle exhaust and its own reaction efficiency to reduce the NOx content in the exhaust to within the required range. However, when the vehicle operates under relatively stable conditions (high-speed conditions), the amount of NOx produced by the engine itself is relatively small. In this case, the urea injection amount calculated using the above method will result in significant urea waste (due to the difference between actual injection and regulatory requirements). The above embodiment can ensure that the urea injection amount is reduced as much as possible while meeting the emission requirements to avoid resource waste.

[0105] Step S202: Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the first cumulative value to the second cumulative value.

[0106] Specifically, the regulations limiting NOx emissions from exhaust gases are based on engine specific emissions. This means that NOx emissions are limited by setting limits on the engine's specific emissions. Generally, the limit for NOx emissions from exhaust gases is 0.25 g / kWh. The unit for engine specific emissions is g / kWh, meaning the mass of NOx emitted per kWh of cumulative power output is the engine's specific emissions at the current moment. The mass of NOx is calculated based on the NOx concentration.

[0107] Step S203: The average value of all the above-mentioned specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the above-mentioned average specific emission to the specific emission threshold to determine the target urea injection quantity. The above-mentioned specific emission threshold is the maximum permissible specific emission value of the above-mentioned engine.

[0108] Specifically, the initial urea injection quantity is a pre-set quantity that ensures the NOx emissions from the engine under any operating condition do not exceed the prescribed limits. The initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. This correction can be performed using multiplication; that is, the target urea injection quantity is the product of the initial urea injection quantity and the ratio of the average specific emission to the specific emission threshold. In practical applications, besides multiplication, other correction methods can also be used to correct the initial urea injection quantity. Correcting the initial urea injection quantity solely based on the ratio of the average specific emission to the specific emission threshold results in low accuracy for the target urea injection quantity. Therefore, the ratio of the average specific emission to the specific emission threshold is pre-corrected to obtain a more accurate correction coefficient. This more accurate correction coefficient is then used to correct the initial urea injection quantity to determine the target urea injection quantity.

[0109] Optionally, the initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity, including: correcting the initial adjustment coefficient using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, wherein the first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR, and the initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold; processing the corrected adjustment coefficient using a moving average method to obtain a target adjustment coefficient; and correcting the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity, wherein the target urea injection quantity is the product of the target adjustment coefficient and the initial urea injection quantity.

[0110] Optionally, the initial adjustment coefficient is corrected using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, including: obtaining a first MAP table and a second MAP table, wherein the first MAP table is used to characterize the relationship between the engine coolant temperature and the first correction coefficient, and the second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient; obtaining the engine coolant temperature and the downstream temperature of the SCR at the current time; determining the first correction coefficient based on the first MAP table and the engine coolant temperature at the current time; determining the second correction coefficient based on the second MAP table and the downstream temperature of the SCR at the current time; and correcting the initial adjustment coefficient using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, wherein the corrected adjustment coefficient is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

[0111] Optionally, after processing the above-mentioned modified adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the above-mentioned target adjustment coefficient to determine the above-mentioned target urea injection quantity, the method further includes: obtaining the widest range of the coefficient, wherein the widest range of the coefficient is a preset widest numerical range of the above-mentioned target adjustment coefficient; and resetting the calculation parameters of the engine if the above-mentioned target adjustment coefficient is not within the widest range of the coefficient, wherein the calculation parameters of the engine include at least: the above-mentioned first cumulative value, the above-mentioned second cumulative value, the specific emission value of the engine, the above-mentioned average specific emission, and the above-mentioned target adjustment coefficient.

[0112] Optionally, acquiring multiple first cumulative values ​​and multiple second cumulative values ​​includes: acquiring the operating parameters of the engine, which include: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening, and brake pedal opening, wherein the engine is installed in the vehicle; and acquiring the first cumulative values ​​and the second cumulative values ​​when the operating parameters of the engine meet a first preset condition, wherein the first preset condition includes: the engine coolant temperature is greater than or equal to a first temperature, the upstream temperature of the SCR is greater than or equal to a second temperature, the vehicle speed is within a first threshold range, the accelerator pedal opening is within a first opening range, and the brake pedal opening is within a second opening range.

[0113] Optionally, in the process of acquiring multiple first cumulative values ​​and multiple second cumulative values, the method further includes: stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the operating parameters of the engine meet the second preset conditions. The second preset conditions include at least one of the following: the engine coolant temperature is lower than the first temperature, the upstream temperature of the SCR is lower than the second temperature, the vehicle speed is not within the first threshold range, the accelerator pedal opening is not within the first opening range, and the brake pedal opening is not within the second opening range.

[0114] Optionally, after stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, the method further includes: obtaining an offset duration, where the offset duration is the duration during which the engine's operating parameters meet the second preset condition; resetting the first cumulative value and the second cumulative value when the offset duration is greater than or equal to the second preset duration; and continuing to calculate the currently calculated first cumulative value and the currently calculated second cumulative value when the offset duration is less than the second preset duration and the engine's operating parameters meet the first preset condition.

[0115] This invention provides a processor for running a program, wherein the program executes the urea injection quantity correction method during operation.

[0116] Specifically, the methods for correcting the urea injection volume include:

[0117] Step S201: Obtain multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one.

[0118] Specifically, in existing technologies, to meet emission requirements for heavy-duty diesel engine exhaust, a Selective Catalytic Reduction (SCR) device is typically added to the aftertreatment system. The SCR injects urea based on the amount of NOx in the vehicle exhaust and its own reaction efficiency to reduce the NOx content in the exhaust to within the required range. However, when the vehicle operates under relatively stable conditions (high-speed conditions), the amount of NOx produced by the engine itself is relatively small. In this case, the urea injection amount calculated using the above method will result in significant urea waste (due to the difference between actual injection and regulatory requirements). The above embodiment can ensure that the urea injection amount is reduced as much as possible while meeting the emission requirements to avoid resource waste.

[0119] Step S202: Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the first cumulative value to the second cumulative value.

[0120] Specifically, the regulations limiting NOx emissions from exhaust gases are based on engine specific emissions. This means that NOx emissions are limited by setting limits on the engine's specific emissions. Generally, the limit for NOx emissions from exhaust gases is 0.25 g / kWh. The unit for engine specific emissions is g / kWh, meaning the mass of NOx emitted per kWh of cumulative power output is the engine's specific emissions at the current moment. The mass of NOx is calculated based on the NOx concentration.

[0121] Step S203: The average value of all the above-mentioned specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the above-mentioned average specific emission to the specific emission threshold to determine the target urea injection quantity. The above-mentioned specific emission threshold is the maximum permissible specific emission value of the above-mentioned engine.

[0122] Specifically, the initial urea injection quantity is a pre-set quantity that ensures the NOx emissions from the engine under any operating condition do not exceed the prescribed limits. The initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. This correction can be performed using multiplication; that is, the target urea injection quantity is the product of the initial urea injection quantity and the ratio of the average specific emission to the specific emission threshold. In practical applications, besides multiplication, other correction methods can also be used to correct the initial urea injection quantity. Correcting the initial urea injection quantity solely based on the ratio of the average specific emission to the specific emission threshold results in low accuracy for the target urea injection quantity. Therefore, the ratio of the average specific emission to the specific emission threshold is pre-corrected to obtain a more accurate correction coefficient. This more accurate correction coefficient is then used to correct the initial urea injection quantity to determine the target urea injection quantity.

[0123] Optionally, the initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity, including: correcting the initial adjustment coefficient using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, wherein the first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR, and the initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold; processing the corrected adjustment coefficient using a moving average method to obtain a target adjustment coefficient; and correcting the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity, wherein the target urea injection quantity is the product of the target adjustment coefficient and the initial urea injection quantity.

[0124] Optionally, the initial adjustment coefficient is corrected using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient, including: obtaining a first MAP table and a second MAP table, wherein the first MAP table is used to characterize the relationship between the engine coolant temperature and the first correction coefficient, and the second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient; obtaining the engine coolant temperature and the downstream temperature of the SCR at the current time; determining the first correction coefficient based on the first MAP table and the engine coolant temperature at the current time; determining the second correction coefficient based on the second MAP table and the downstream temperature of the SCR at the current time; and correcting the initial adjustment coefficient using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, wherein the corrected adjustment coefficient is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

[0125] Optionally, after processing the above-mentioned modified adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the above-mentioned target adjustment coefficient to determine the above-mentioned target urea injection quantity, the method further includes: obtaining the widest range of the coefficient, wherein the widest range of the coefficient is a preset widest numerical range of the above-mentioned target adjustment coefficient; and resetting the calculation parameters of the engine if the above-mentioned target adjustment coefficient is not within the widest range of the coefficient, wherein the calculation parameters of the engine include at least: the above-mentioned first cumulative value, the above-mentioned second cumulative value, the specific emission value of the engine, the above-mentioned average specific emission, and the above-mentioned target adjustment coefficient.

[0126] Optionally, acquiring multiple first cumulative values ​​and multiple second cumulative values ​​includes: acquiring the operating parameters of the engine, which include: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening, and brake pedal opening, wherein the engine is installed in the vehicle; and acquiring the first cumulative values ​​and the second cumulative values ​​when the operating parameters of the engine meet a first preset condition, wherein the first preset condition includes: the engine coolant temperature is greater than or equal to a first temperature, the upstream temperature of the SCR is greater than or equal to a second temperature, the vehicle speed is within a first threshold range, the accelerator pedal opening is within a first opening range, and the brake pedal opening is within a second opening range.

[0127] Optionally, in the process of acquiring multiple first cumulative values ​​and multiple second cumulative values, the method further includes: stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the operating parameters of the engine meet the second preset conditions. The second preset conditions include at least one of the following: the engine coolant temperature is lower than the first temperature, the upstream temperature of the SCR is lower than the second temperature, the vehicle speed is not within the first threshold range, the accelerator pedal opening is not within the first opening range, and the brake pedal opening is not within the second opening range.

[0128] Optionally, after stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, the method further includes: obtaining an offset duration, where the offset duration is the duration during which the engine's operating parameters meet the second preset condition; resetting the first cumulative value and the second cumulative value when the offset duration is greater than or equal to the second preset duration; and continuing to calculate the currently calculated first cumulative value and the currently calculated second cumulative value when the offset duration is less than the second preset duration and the engine's operating parameters meet the first preset condition.

[0129] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0130] Step S201: Obtain multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one.

[0131] Step S202: Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the first cumulative value to the second cumulative value.

[0132] Step S203: The average value of all the above-mentioned specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the above-mentioned average specific emission to the specific emission threshold to determine the target urea injection quantity. The above-mentioned specific emission threshold is the maximum permissible specific emission value of the above-mentioned engine.

[0133] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0134] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0135] Step S201: Obtain multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one.

[0136] Step S202: Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the first cumulative value to the second cumulative value.

[0137] Step S203: The average value of all the above-mentioned specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the above-mentioned average specific emission to the specific emission threshold to determine the target urea injection quantity. The above-mentioned specific emission threshold is the maximum permissible specific emission value of the above-mentioned engine.

[0138] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0139] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0140] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0141] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0142] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0143] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0144] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0145] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0146] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0147] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0148] 1) The urea injection quantity correction method of this application first obtains multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission per unit mass within the first preset time period. The first cumulative value corresponds one-to-one with the second cumulative value. Then, multiple engine specific emission values ​​are obtained, where one specific emission value is the ratio of the corresponding first cumulative value to the second cumulative value. Finally, the average value of all specific emission values ​​is determined as the average specific emission, and the initial urea injection quantity is corrected according to the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. The specific emission threshold is the maximum allowable specific emission value of the engine. This method calculates the specific emission based on the actual work done by the engine, adjusts the urea injection quantity within the maximum allowable specific emission of the engine, reduces urea injection, lowers operating costs, and solves the problem that the existing engine urea injection quantity calculation method has low accuracy, leading to excessive urea injection and resource waste.

[0149] 2) The urea injection quantity correction device of this application includes a first acquisition unit, a second acquisition unit, and a determination unit. The first acquisition unit is used to acquire multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period, and the second cumulative value is the cumulative value of NOx emission mass per unit mass within a first preset time period, where NOx emission mass per unit mass is the mass of NOx emitted in the exhaust gas downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one. The second acquisition unit is used to acquire multiple engine specific emission values, where one specific emission value is the ratio of the corresponding first cumulative value to the second cumulative value. The determination unit is used to determine the average of all specific emission values ​​as the average specific emission, and to correct the initial urea injection quantity based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity. The specific emission threshold is the maximum allowable specific emission value of the engine. This device calculates the specific emission based on the actual work done by the engine, adjusts the urea injection quantity within the maximum allowable specific emission of the engine, reduces urea injection, lowers operating costs, and solves the problem that the existing calculation method for engine urea injection quantity has low accuracy, leading to excessive urea injection and resource waste.

[0150] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for correcting urea injection volume, characterized in that, include: Multiple first cumulative values ​​and multiple second cumulative values ​​are obtained. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one. Obtain the specific emission values ​​of multiple engines, wherein one of the specific emission values ​​is the ratio of the corresponding first cumulative value to the second cumulative value; The average of all the specific emission values ​​is determined as the average specific emission, and the initial urea injection amount is corrected according to the ratio of the average specific emission to the specific emission threshold to determine the target urea injection amount, wherein the specific emission threshold is the maximum permissible specific emission value of the engine; The initial urea injection quantity is corrected based on the ratio of the average specific emission to the specific emission threshold to determine the target urea injection quantity, including: The initial adjustment coefficient is corrected by using a first correction coefficient and a second correction coefficient to obtain a corrected adjustment coefficient. The first correction coefficient is a correction coefficient obtained based on the engine coolant temperature, and the second correction coefficient is a correction coefficient obtained based on the downstream temperature of the SCR. The initial adjustment coefficient is the ratio of the average specific emission to the specific emission threshold. The target adjustment coefficient is obtained by processing the modified adjustment coefficient using the moving average method. The initial urea injection quantity is corrected using the target adjustment coefficient to determine the target urea injection quantity, which is the product of the target adjustment coefficient and the initial urea injection quantity. Acquiring multiple first cumulative values ​​and multiple second cumulative values ​​includes: acquiring the engine's operating parameters, which include: engine coolant temperature, upstream temperature of the SCR, vehicle speed, accelerator pedal opening, and brake pedal opening, wherein the engine is installed in the vehicle; and acquiring the first cumulative values ​​and second cumulative values ​​when the engine's operating parameters meet first preset conditions, wherein the first preset conditions include: the engine coolant temperature is greater than or equal to a first temperature, the upstream temperature of the SCR is greater than or equal to a second temperature, the vehicle speed is within a first threshold range, the accelerator pedal opening is within a first opening range, and the brake pedal opening is within a second opening range.

2. The correction method according to claim 1, characterized in that, The initial adjustment coefficient is corrected using a first correction factor and a second correction factor to obtain the corrected adjustment coefficient, which includes: Obtain a first MAP table and a second MAP table. The first MAP table is used to characterize the relationship between the engine coolant temperature and the first correction coefficient. The second MAP table is used to characterize the relationship between the downstream temperature of the SCR and the second correction coefficient. Obtain the engine coolant temperature and the downstream temperature of the SCR at the current moment; The first correction factor is determined based on the first MAP table and the engine coolant temperature at the current moment; The second correction factor is determined based on the second MAP table and the downstream temperature of the SCR at the current moment; The initial adjustment coefficient is corrected using the first correction coefficient and the second correction coefficient to obtain the corrected adjustment coefficient, which is the product of the initial adjustment coefficient, the first correction coefficient, and the second correction coefficient.

3. The correction method according to claim 1, characterized in that, After processing the corrected adjustment coefficient using the moving average method to obtain the target adjustment coefficient, and before correcting the initial urea injection quantity using the target adjustment coefficient to determine the target urea injection quantity, the method further includes: Obtain the widest range of coefficients, where the widest range of coefficients is the preset widest numerical range of the target adjustment coefficient; If the target adjustment coefficient is not within the widest range, the calculation parameters of the engine are reset. The calculation parameters of the engine include at least: the first cumulative value, the second cumulative value, the specific emission value of the engine, the average specific emission, and the target adjustment coefficient.

4. The correction method according to claim 1, characterized in that, In the process of obtaining multiple first cumulative values ​​and multiple second cumulative values, the method further includes: When the engine's operating parameters meet the second preset conditions, the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value is stopped. The second preset conditions include at least one of the following: the engine coolant temperature is lower than the first temperature, the upstream temperature of the SCR is lower than the second temperature, the vehicle speed is not within the first threshold range, the accelerator pedal opening is not within the first opening range, and the brake pedal opening is not within the second opening range.

5. The correction method according to claim 4, characterized in that, After stopping the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value when the engine's operating parameters meet the second preset condition, the method further includes: Obtain the offset duration, which is the duration during which the engine's operating parameters satisfy the second preset condition; If the offset duration is greater than or equal to the second preset duration, the first accumulated value and the second accumulated value are reset. If the offset duration is less than the second preset duration and the engine's operating parameters meet the first preset condition, the calculation of the currently calculated first cumulative value and the currently calculated second cumulative value continues.

6. A device for correcting urea injection volume, characterized in that, The correction device corrects the urea injection quantity using the urea injection quantity correction method as described in any one of claims 1 to 5, and the device comprises: The first acquisition unit is used to acquire multiple first cumulative values ​​and multiple second cumulative values. The first cumulative value is the cumulative value of the work done by the engine within a first preset time period. The second cumulative value is the cumulative value of NOx emission mass per unit mass within the first preset time period. The NOx emission mass per unit mass is the mass of NOx in the exhaust gas emitted by the downstream of the SCR per unit time. The first cumulative value and the second cumulative value correspond one-to-one. The second acquisition unit is used to acquire the specific emission values ​​of a plurality of the engines, wherein one of the specific emission values ​​is the ratio of the corresponding first cumulative value to the second cumulative value; A determining unit is configured to determine the average of all the specific emission values ​​as the average specific emission, and to correct the initial urea injection quantity based on the ratio of the average specific emission to the specific emission threshold, thereby determining the target urea injection quantity, wherein the specific emission threshold is the maximum permissible specific emission value of the engine.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the urea injection quantity correction method according to any one of claims 1 to 5.

8. An electronic device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including a method for performing a correction method for urea injection volume according to any one of claims 1 to 5.

Images