Engine exhaust ammonia leakage detection method, device and engine control system

Abstract

The application provides an engine exhaust ammonia leakage detection method, device and engine control system. According to the scheme, after the original exhaust NOx is in a stable state, the original exhaust NOx of the engine is adjusted to a target value. During the adjustment process, the measurement values of an upstream NOx sensor and a downstream NOx sensor are detected in real time. In combination with the measurement values of the upstream NOx sensor and the downstream NOx sensor, ammonia leakage in the exhaust can be accurately judged and identified, and the false alarm condition of the SCR efficiency fault caused by ammonia leakage in the exhaust can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the engine technical field, specifically relates to a kind of engine ammonia leakage detection method, device, equipment and engine control system. BACKGROUND

[0002] In order to reduce the pollution of engine exhaust to air, it is necessary to reduce the harmful gas components in the exhaust, and it is necessary to ensure that the conversion efficiency of the Selective Catalyst Reduction (hereinafter referred to as SCR) system is above 95%, while also ensuring that the NH3 in the exhaust cycle exhaust is not more than 10 ppm, and in the actual application process of the whole vehicle, nitrogen oxides NOx in the exhaust is eliminated by urea, in order to ensure that the emission of nitrogen oxides NOx in the exhaust is within the permitted range, the engine system usually has urea over-injection phenomenon, and the ammonia nitrogen ratio of urea injection is generally above 1.05-1.10. If urea over-injection is serious, it will cause excessive ammonia leakage, causing NH3 pollution to the environment.

[0003] Currently, diesel engine aftertreatment is equipped with upstream NOx sensor and downstream NOx sensor, which can monitor the upstream and downstream NOx emission results respectively, but NOx cannot accurately distinguish NOx and NH3. If the ammonia nitrogen ratio of urea is too large, the NH3 emission in the exhaust is too high, and there is ammonia leakage in the exhaust, the downstream NOx sensor measurement value will be higher than the actual downstream NOx emission result, which is easy to cause false alarm of SCR efficiency fault. SUMMARY

[0004] Therefore, the present application provides an engine exhaust ammonia leakage detection method, device and engine control system to identify whether there is ammonia leakage in the exhaust, and to prevent false alarm of SCR efficiency fault.

[0005] To achieve the above object, the present application provides the following technical scheme:

[0006] An engine exhaust ammonia leakage detection method, comprising:

[0007] determining whether the original NOx of the engine is in a stable state;

[0008] when the original NOx is in a stable state, controlling the original NOx of the engine to adjust to a target value;

[0009] obtaining the measurement values of the upstream NOx sensor and the downstream NOx sensor during the process of adjusting the original NOx to the target value;

[0010] based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, determining whether there is ammonia leakage in the exhaust.

[0011] Optionally, in the engine exhaust ammonia leakage detection method, when the raw emission NOx is not in a stable state, the method further comprises:

[0012] Adjusting a target combustion parameter of the engine so that the raw emission NOx of the engine enters a stable state.

[0013] Optionally, in the engine exhaust ammonia leakage detection method, adjusting the target combustion parameter of the engine so that the raw emission NOx of the engine enters a stable state comprises:

[0014] Adjusting an injection timing, a rail pressure, and an EGR rate of the engine so that the raw emission NOx enters a stable state.

[0015] Optionally, in the engine exhaust ammonia leakage detection method, determining whether ammonia leakage exists in the exhaust based on measurement values of the upstream NOx sensor and the downstream NOx sensor comprises:

[0016] Based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, calculating a change mode of the NOx conversion efficiency in a process in which the raw emission NOx of the engine is adjusted to a target value.

[0017] Determining whether ammonia leakage exists in the exhaust based on the change mode of the NOx conversion efficiency.

[0018] Optionally, in the engine exhaust ammonia leakage detection method, adjusting the raw emission NOx of the engine to a target value comprises: adjusting the raw emission NOx of the engine to a first target value.

[0019] Optionally, in the engine exhaust ammonia leakage detection method, determining whether ammonia leakage exists in the exhaust based on measurement values of the upstream NOx sensor and the downstream NOx sensor comprises:

[0020] Based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, calculating a NOx conversion efficiency corresponding to each time point in a process in which the raw emission NOx of the engine is adjusted to a first target value.

[0021] When the NOx conversion efficiency monotonically decreases in the process in which the raw emission NOx of the engine is adjusted to the first target value, determining that no ammonia leakage exists in the exhaust.

[0022] When the NOx conversion efficiency first increases and then decreases in the process in which the raw emission NOx of the engine is adjusted to the first target value, determining that ammonia leakage exists in the exhaust.

[0023] Optionally, in the engine exhaust ammonia leakage detection method, the process of adjusting the original emission NOx of the engine to a target value comprises: controlling the original emission NOx of the engine to decrease to a second target value.

[0024] Based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, it is determined whether there is ammonia leakage in the exhaust gas, comprising:

[0025] Based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, the NOx conversion efficiency corresponding to each time point in the process of reducing the original emission NOx of the engine to the second target value is calculated.

[0026] When the NOx conversion efficiency monotonically increases or first increases and then decreases in the process of reducing the original emission NOx of the engine to the second target value, it is determined that there is no ammonia leakage in the exhaust gas.

[0027] When the NOx conversion efficiency monotonically decreases in the process of increasing the original emission NOx of the engine to the first target value, it is determined that there is ammonia leakage in the exhaust gas.

[0028] Optionally, in the engine exhaust ammonia leakage detection method, based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, it is determined whether there is ammonia leakage in the exhaust gas, comprising:

[0029] In the process of adjusting the original emission NOx of the engine to a target value, the change mode of the measurement value of the downstream NOx sensor is used to determine whether there is ammonia leakage in the exhaust gas.

[0030] Optionally, in the engine exhaust ammonia leakage detection method, before determining whether the original emission NOx of the engine is in a stable state, the method further comprises:

[0031] The running state and the aftertreatment state of the engine are determined to be in a stable state, and when the running state and the aftertreatment state of the engine are in a stable state, the subsequent process is continued.

[0032] An engine exhaust ammonia leakage detection device, comprising:

[0033] An original emission state determination unit is configured to determine whether the original emission NOx of the engine is in a stable state.

[0034] An ammonia nitrogen ratio control unit is configured to control the original emission NOx of the engine to adjust to a target value when the original emission NOx is in a stable state.

[0035] A leakage judgment unit is configured to obtain measurement values of the upstream NOx sensor and the downstream NOx sensor during adjustment of the original exhaust NOx to a target value; and judge whether ammonia leakage exists in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor.

[0036] An engine control system comprises a memory and a processor;

[0037] The memory is configured to store a program.

[0038] The processor is configured to execute the program to implement each step of the engine exhaust ammonia leakage detection method.

[0039] In the above technical solution, after the original exhaust NOx is in a stable state, the original exhaust NOx of the engine is adjusted to a target value, and in the adjustment process, the measurement values of the upstream NOx sensor and the downstream NOx sensor are detected in real time. In combination with the measurement values of the upstream NOx sensor and the downstream NOx sensor, ammonia leakage in the exhaust gas can be accurately judged and identified, and the false alarm of the SCR efficiency fault caused by ammonia leakage in the exhaust gas can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0041] Figure 1 A flowchart of an engine exhaust ammonia leakage detection method disclosed in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of an ammonia leakage monitoring working condition identification method disclosed in an embodiment of the present application;

[0043] Figure 3 A flowchart of an engine exhaust ammonia leakage detection method disclosed in another embodiment of the present application;

[0044] Figure 4 A flowchart of an engine exhaust ammonia leakage detection method disclosed in another embodiment of the present application;

[0045] Figure 5 A flowchart of an engine exhaust ammonia leakage detection method disclosed in another embodiment of the present application;

[0046] Figure 6 A flowchart of an engine exhaust ammonia leakage detection method disclosed in another embodiment of the present application;

[0047] Figure 7 A structure schematic diagram of an engine exhaust ammonia leakage detection device disclosed in an embodiment of the present application is shown in the figure.

[0048] Figure 8 A structure schematic diagram of an engine control system disclosed in an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0050] In the present application, when the original exhaust NOx of the engine is in a stable state, the ammonia nitrogen ratio of urea injection is adjusted, and whether ammonia leakage exists in the engine exhaust is accurately identified by judging the measurement values of the upstream NOx sensor and the downstream NOx sensor after adjusting the ammonia nitrogen ratio.

[0051] Specifically, referring to Figure 1 The engine exhaust ammonia leakage detection method disclosed in the embodiments of the present application comprises:

[0052] Step S101: judging whether the original exhaust NOx of the engine is in a stable state.

[0053] In the present application, whether the original exhaust NOx is in a stable state can be judged based on the fluctuation amplitude of the NOx actual value corresponding to the current original exhaust of the engine. The NOx actual value can be directly called in the ECU (Electronic Control Unit), and after obtaining the NOx actual value corresponding to the current original exhaust of the engine, it is judged whether the fluctuation range is greater than a preset fluctuation range. The preset fluctuation range can be set by the user as required. If the original exhaust NOx emission fluctuation is within ±0.5, it can be considered that the original exhaust NOx is in a stable state.

[0054] Step S102: when the original exhaust NOx is in a stable state, controlling the original exhaust NOx of the engine to adjust to a target value.

[0055] When the original exhaust NOx is in a stable state, the change trend of the measured values of the upstream NOx sensor and the downstream NOx sensor is different in the presence of ammonia leakage and in the absence of ammonia leakage, and therefore, in this step, when it is detected that the original exhaust NOx is in a stable state, the original exhaust NOx can be controlled to increase or decrease, and in the process of increasing or decreasing the original exhaust NOx, the measured values of the upstream NOx sensor and the downstream NOx sensor are collected in real time, and whether ammonia leakage exists in the exhaust gas is determined based on the change trend of the measured values of the upstream NOx sensor and the downstream NOx sensor in the process. Specifically, whether the original exhaust NOx is controlled to increase or decrease can be controlled according to design requirements.

[0056] Step S103: determining whether ammonia leakage exists in the exhaust gas based on the measured values of the upstream NOx sensor and the downstream NOx sensor.

[0057] In the process of controlling the original exhaust NOx to increase or decrease to the target value, the measured values of the upstream NOx sensor and the downstream NOx sensor in the process of adjusting the original exhaust NOx are obtained, and the measured values of the upstream NOx sensor and the downstream NOx sensor are further analyzed to determine whether ammonia leakage exists in the exhaust gas.

[0058] The technical solution disclosed in the above embodiments of the application can control the original exhaust NOx of the engine to adjust to a target value after the original exhaust NOx is in a stable state, and in the adjustment process, the measured values of the upstream NOx sensor and the downstream NOx sensor are detected in real time, and the measured values of the upstream NOx sensor and the downstream NOx sensor can be combined to accurately determine and identify ammonia leakage in the exhaust gas, thereby avoiding false alarm of SCR efficiency failure caused by ammonia leakage in the exhaust gas.

[0059] In the technical solution disclosed in the embodiments, the original exhaust NOx can be adjusted by adjusting the target combustion parameters of the engine, and when the original exhaust NOx is not in a stable state, the target combustion parameters of the engine can be adjusted to make the original exhaust NOx of the engine enter a stable state. Specifically, the target combustion parameters can be injection timing, rail pressure, and EGR rate, and the injection timing, rail pressure, and EGR rate are adjusted to make the original exhaust NOx of the engine enter and remain in a stable state, so as to prevent misjudgment of the judgment result of ammonia leakage caused by fluctuations in the original exhaust NOx.

[0060] In the technical solution disclosed in the embodiment, in order to further eliminate the factors affecting the SCR conversion efficiency and improve the accuracy of the judgment result of ammonia leakage, in the technical solution disclosed in the embodiment, before judging whether the original exhaust NOx of the engine is in a stable state, it is necessary to ensure that the operating state and the aftertreatment state of the engine are relatively stable. When the operating state and the aftertreatment state of the engine are in a stable state, the subsequent ammonia leakage judgment process can be continued. If the operating state and the aftertreatment state of the engine are not in a stable state, it is necessary to continue waiting until the operating state and the aftertreatment state of the engine enter a stable state. Specifically, see Figure 2 The operating state of the engine can be identified through the engine operating mode, the urea injection state, the NOx sensor working state, the change of the speed, the change of the torque, and the change of the SCR temperature and the change of the exhaust flow. After the above-mentioned judgment meets the ammonia leakage monitoring function condition, it is determined that the operating state and the aftertreatment state of the engine are relatively stable, and the factors affecting the SCR conversion efficiency are eliminated. Specifically, the ammonia leakage monitoring function condition can refer to: the engine operating mode is stable, the urea injection state is normal without related fault error, the NOx sensor is normal without related fault error, the speed and the torque are in a certain interval, the change amplitude of the SCR temperature is not more than a certain value within a certain time, and the change amplitude of the exhaust flow is not more than a certain value. In the above-mentioned condition, the specific values of the “certain interval” and the “certain value” can be configured according to the corresponding parameter type.

[0061] In the embodiment, in the process of adjusting the original exhaust NOx, when judging whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, the change mode of the NOx conversion efficiency can be used to judge whether there is ammonia leakage in the exhaust gas, or the change mode of the measurement value of the downstream NOx sensor can be used to directly judge whether there is ammonia leakage in the exhaust gas.

[0062] Controlling the original exhaust NOx of the engine to adjust to a target value can include reducing the original exhaust NOx and increasing the original exhaust NOx, and specifically includes: controlling the original exhaust NOx of the engine to increase to a first target value, and controlling the original exhaust NOx of the engine to decrease to a second target value. The specific values of the first target value and the second target value can be set according to user demand, for example, in the embodiment, the second target value can be the original exhaust NOx corresponding to the NOx specific emission of 2 g / (kw.h) after reduction, that is, the initial value of the original exhaust NOx minus 2 g / (kw.h).

[0063] When controlling the original exhaust NOx of the engine to adjust to a target value is to control the original exhaust NOx of the engine to increase to a first target value, see Figure 3 , based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, judging whether there is ammonia leakage in the exhaust gas includes:

[0064] Step S301: Calculate the NOx conversion efficiency during the process of increasing the engine-out NOx to the first target value.

[0065] In this step, the NOx conversion efficiency changing in real time during the process of increasing the engine-out NOx to the first target value is calculated based on the measurement values of the upstream NOx sensor and the downstream NOx sensor.

[0066] Step S302: Calculate the changing curve of the NOx conversion efficiency during the process of increasing the engine-out NOx to the first target value.

[0067] In this step, the NOx conversion efficiency at each time during the process of increasing the engine-out NOx to the first target value is calculated based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, and the changing curve of the NOx conversion efficiency during the process of increasing the engine-out NOx to the first target value is generated.

[0068] Step S303: Determine whether the changing curve is monotonously decreasing or first increasing and then decreasing.

[0069] This step analyzes the changing trend of the NOx conversion efficiency based on the changing curve of the NOx conversion efficiency. When it is determined from the changing curve of the NOx conversion efficiency that the NOx conversion efficiency is monotonously decreasing during the process of increasing the engine-out NOx to the first target value, it is determined that there is no ammonia leakage in the exhaust gas, and when the NOx conversion efficiency is first increasing and then decreasing, it is determined that there is ammonia leakage in the exhaust gas. At this time, the analysis result can be displayed to the user when it is determined that there is ammonia leakage in the exhaust gas, so that the user can timely handle the engine fault.

[0070] When the process of adjusting the engine-out NOx to the target value is the process of decreasing the engine-out NOx to the second target value, referring to Figure 4 , the step of determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor comprises:

[0071] Step S401: Calculate the real-time NOx conversion efficiency during the process of decreasing the engine-out NOx to the second target value.

[0072] In this step, the real-time NOx conversion efficiency during the process of decreasing the engine-out NOx to the second target value is calculated based on the measurement values of the upstream NOx sensor and the downstream NOx sensor.

[0073] Step S402: Calculate the change curve of the NOx conversion efficiency during the process of reducing the original exhaust NOx to the second target value.

[0074] In this step, based on the measurement values of the upstream NOx sensor and the downstream NOx sensor during the process of reducing the original exhaust NOx to the second target value, the NOx conversion efficiency after adjusting the ammonia nitrogen ratio at each time is calculated, and a change curve of the NOx conversion efficiency during the process of adjusting the ammonia nitrogen ratio is generated.

[0075] Step S403: Determine whether the change curve is monotonously increasing, first increasing and then decreasing, or monotonously decreasing.

[0076] In this step, when the NOx conversion efficiency is monotonously increasing or first increasing and then decreasing during the process of reducing the original exhaust NOx to the second target value, it is determined that there is no ammonia leakage in the exhaust gas according to the change curve of the NOx conversion efficiency. When the NOx conversion efficiency is monotonously decreasing during the process of reducing the original exhaust NOx to the second target value, it is determined that there is ammonia leakage in the exhaust gas. At this time, when it is determined that there is ammonia leakage in the exhaust gas, the analysis result can be displayed to the user to facilitate the user to handle the engine fault in time.

[0077] When the original exhaust NOx of the engine is controlled to the target value, it is controlled to increase to the first target value. Based on the change mode of the measurement value of the downstream NOx sensor, it can also be determined whether there is ammonia leakage in the exhaust gas, see Figure 5 The process can include:

[0078] Step S501: Calculate the measurement value of the downstream NOx sensor during the process of increasing the NOx to the first target value.

[0079] Step S502: Construct a change curve of the measurement value of the downstream NOx sensor during the process of increasing the NOx to the first target value.

[0080] In this step, based on the measurement value of the downstream NOx sensor during the process of increasing the NOx to the first target value, a change curve of the measurement value of the downstream NOx sensor is constructed.

[0081] Step S503: Determine whether the change curve is monotonously increasing or first decreasing and then increasing.

[0082] The step analyzes the change trend of the measurement value of the downstream NOx sensor based on the change curve of the measurement value of the downstream NOx sensor. When it is determined from the change curve of the measurement value of the downstream NOx sensor that the measurement value of the downstream NOx sensor monotonously increases, it is determined that there is no ammonia leakage in the exhaust gas, and when the measurement value of the downstream NOx sensor first decreases and then increases, it is determined that there is ammonia leakage in the exhaust gas. At this time, when it is determined that there is ammonia leakage in the exhaust gas, the analysis result can be displayed to the user to facilitate the user to handle the engine fault in time.

[0083] When the original exhaust NOx of the engine is controlled to decrease to the second target value, referring to Figure 6 , the determination of whether there is ammonia leakage in the exhaust gas based on the change mode of the measurement value of the downstream NOx sensor includes:

[0084] Step S601: obtaining the measurement value of the downstream NOx sensor during the process of reducing the NOx to the second target value.

[0085] Step 6502: calculating the change curve of the measurement value of the downstream NOx sensor during the process of reducing the NOx to the second target value.

[0086] In this step, the change curve of the measurement value of the downstream NOx sensor is generated based on the measurement value of the downstream NOx sensor during the process of reducing the NOx to the second target value.

[0087] Step S603: determining whether the change curve monotonously decreases, first decreases and then increases, or monotonously increases;

[0088] The step analyzes the change trend of the measurement value of the downstream NOx sensor based on the change curve of the measurement value of the downstream NOx sensor. When it is determined from the change curve of the measurement value of the downstream NOx sensor that the measurement value of the downstream NOx sensor monotonously decreases or first decreases and then increases, it is determined that there is no ammonia leakage in the exhaust gas, and when the measurement value of the downstream NOx sensor monotonously increases, it is determined that there is ammonia leakage in the exhaust gas. At this time, when it is determined that there is ammonia leakage in the exhaust gas, the analysis result can be displayed to the user to facilitate the user to handle the engine fault in time.

[0089] In the technical solution disclosed in this embodiment, after the determination of whether there is ammonia leakage in the exhaust gas is completed, the engine combustion parameter control and the original exhaust NOx control can be exited, so that the engine combustion parameter control and the original exhaust NOx control are restored to the previous control state, and the related parameters are restored to the original state for continuous operation.

[0090] From the above scheme, it can be seen that the patent identifies the operating condition of the engine, and in the case that urea is normally injected and the upstream NOx sensor and the downstream NOx sensor are normally working, the engine is determined to be running in a relatively stable condition through the aftertreatment temperature and the exhaust flow, and the ammonia leakage monitoring function is started. After the ammonia leakage monitoring function is started, the relevant combustion parameters of the engine are controlled to ensure that the original exhaust NOx of the engine is relatively stable. After ensuring that the engine condition is relatively stable and the original exhaust is relatively stable, the original exhaust NOx is controlled to adjust to the target value, and the NOx conversion efficiency in the process is calculated through the measurement values of the upstream NOx sensor and the downstream NOx sensor. Based on the change mode of the NOx conversion efficiency or the measurement value of the downstream NOx sensor, it is determined whether there is ammonia leakage in the tail gas. Specifically, when the original exhaust NOx is controlled to rise to the first target value, if the conversion efficiency directly appears monotone decrease or the measurement value of the downstream NOx sensor directly rises, it is determined that there is no ammonia leakage in the tail gas; if the conversion efficiency directly appears first rise and then decrease or the measurement value of the downstream NOx sensor first decreases and then rises, it is determined that there is ammonia leakage in the tail gas. When the original exhaust NOx is controlled to decrease to the second target value, if the conversion efficiency appears monotone rise or first rise and then decrease or the measurement value of the downstream NOx sensor directly decreases and then rises, it is determined that there is no ammonia leakage in the tail gas; if the conversion efficiency directly appears monotone decrease or the measurement value of the downstream NOx sensor monotone rise, it is determined that there is ammonia leakage in the tail gas.

[0091] An engine tail gas ammonia leakage detection device is disclosed in the embodiment. For specific working content of each unit in the device, please refer to the content of the method embodiment described above.

[0092] The engine tail gas ammonia leakage detection device provided by the embodiment of the application is described below. The engine tail gas ammonia leakage detection device described below can be correspondingly referred to the engine tail gas ammonia leakage detection method described above.

[0093] Referring to Figure 7 , the engine tail gas ammonia leakage detection device can include:

[0094] The original exhaust state judgment unit 10, the original exhaust NOx adjustment unit 20, and the leakage judgment unit 30;

[0095] The original exhaust state judgment unit 10 corresponds to step S101 in the above method, and is used to determine whether the original exhaust NOx of the engine is in a stable state;

[0096] The original exhaust NOx adjustment unit 20 corresponds to step S102 in the above method, and when the original exhaust NOx is in a stable state, the original exhaust NOx of the engine is controlled to adjust to a target value;

[0097] The leakage judgment unit 30 corresponds to step S103 in the above method, and is configured to obtain the measurement values of the upstream NOx sensor and the downstream NOx sensor in the process of adjusting the original exhaust NOx to the target value; and judge whether ammonia leakage exists in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor.

[0098] The specific functions and specific execution strategies of the original exhaust state judgment unit 10, the original exhaust NOx adjustment unit 20 and the leakage judgment unit 30 can be referred to the method embodiments described above, and will not be repeated here.

[0099] In addition, the application also discloses an engine control system, which can be referred to as Figure 8 The system can include at least one processor 100, at least one communication interface 200, at least one memory 300 and at least one communication bus 400, the memory 300 is configured to store programs; the processor 100 is configured to execute the programs.

[0100] In the embodiment of the application, the number of processors 100, communication interfaces 200, memories 300 and communication buses 400 is at least one, and the processor 100, the communication interface 200 and the memory 300 complete the communication between each other through the communication bus 400; obviously, Figure 8 The communication connection shown in the processor 100, the communication interface 200, the memory 300 and the communication bus 400 shown in the communication connection is only optional;

[0101] Optionally, the communication interface 200 can be the interface of the communication module, such as the interface of the GSM module.

[0102] The processor 100 can be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the application.

[0103] The memory 300 can include a high-speed RAM memory, and can also include a non-volatile memory, such as at least one disk memory.

[0104] The processor 100 specifically executes the programs to realize each step of the engine exhaust ammonia leakage detection method embodiment as described in any of the above.

[0105] For example, the processor 100 is configured to:

[0106] Judge whether the original exhaust NOx of the engine is in a stable state;

[0107] When the original exhaust NOx is in a steady state, the original exhaust NOx of the engine is controlled to a target value;

[0108] During the process of obtaining the original exhaust NOx to the target value, the measurement values of the upstream NOx sensor and the downstream NOx sensor;

[0109] Based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, it is determined whether there is ammonia leakage in the exhaust gas.

[0110] The processor 100 is also configured to perform the steps of the above-mentioned other engine exhaust ammonia leakage detection method embodiments, which will not be repeated here.

[0111] Further, the application also discloses an automobile, which can be applied with the above-mentioned engine control system, and the automobile can be a fuel car, a gas car or a hybrid car.

[0112] For the convenience of description, the above system is described in various modules in terms of functions. Of course, in the implementation of the present application, the functions of each module can be implemented in one or more software and / or hardware.

[0113] Each embodiment in the specification is described in a progressive manner, and the same and similar parts of each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, it is described more simply, and the relevant parts can be referred to the part of the method embodiment. The above-described system and system embodiment are only illustrative, and the units described as separate components can be or can not be physically separated, and the components displayed as units can be or can not be physical units, that is, they can be located in one place or distributed on multiple network units. According to the actual needs, some or all of the modules can be selected to achieve the purpose of the embodiment. Those skilled in the art can understand and implement without creative labor.

[0114] The professional person can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present text can be realized by electronic hardware, computer software or a combination of both. In order to clearly show the interchangeability of hardware and software, the components and steps of each example have been described in the above description. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The professional person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0115] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM, flash memory, ROM, electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and

[0116] It is also important to note that the use of relational terms, such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0117] The above description of disclosed embodiments provides information sufficient to understand how to make and use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without the use of the innovative principles of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An engine exhaust ammonia slip detection method, characterized by, The method comprises: determining whether the original exhaust NOx of the engine is in a stable state; controlling the original exhaust NOx of the engine to adjust to a target value when the original exhaust NOx is in the stable state; acquiring measurement values of an upstream NOx sensor and a downstream NOx sensor during the process of adjusting the original exhaust NOx to the target value; determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor; determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, comprising: calculating the change mode of the NOx conversion efficiency during the process of adjusting the original exhaust NOx of the engine to the target value based on the measurement values of the upstream NOx sensor and the downstream NOx sensor; and determining whether there is ammonia leakage in the exhaust gas based on the change mode of the NOx conversion efficiency; controlling the original exhaust NOx of the engine to adjust to a target value, comprising: controlling the original exhaust NOx of the engine to increase to a first target value; determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, comprising: calculating the NOx conversion efficiency corresponding to each time point during the process of increasing the original exhaust NOx of the engine to the first target value based on the acquired measurement values of the upstream NOx sensor and the downstream NOx sensor; determining that there is no ammonia leakage in the exhaust gas when the NOx conversion efficiency monotonously decreases during the process of increasing the original exhaust NOx of the engine to the first target value; and determining that there is ammonia leakage in the exhaust gas when the NOx conversion efficiency increases first and then decreases during the process of increasing the original exhaust NOx of the engine to the first target value. Or, controlling the original exhaust NOx of the engine to adjust to a target value, comprising: controlling the original exhaust NOx of the engine to decrease to a second target value; determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, comprising: calculating the NOx conversion efficiency corresponding to each time point during the process of decreasing the original exhaust NOx of the engine to the second target value based on the acquired measurement values of the upstream NOx sensor and the downstream NOx sensor; determining that there is no ammonia leakage in the exhaust gas when the NOx conversion efficiency monotonously increases or increases first and then decreases during the process of decreasing the original exhaust NOx of the engine to the second target value; and determining that there is ammonia leakage in the exhaust gas when the NOx conversion efficiency monotonously decreases during the process of decreasing the original exhaust NOx of the engine to the second target value.

2. The engine exhaust ammonia slip detection method of claim 1, wherein, When the original exhaust NOx is not in the stable state, the method further comprises: adjusting a target combustion parameter of the engine to make the original exhaust NOx of the engine enter the stable state.

3. The method of claim 2, wherein, Adjusting a target combustion parameter of the engine to make the original exhaust NOx of the engine enter the stable state, comprising: adjusting the injection timing, rail pressure and EGR rate of the engine to make the original exhaust NOx enter the stable state.

4. The method of claim 1, wherein, Determining whether there is ammonia leakage in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor, comprising: The process of adjusting the raw exhaust NOx of the engine to a target value, based on the change mode of the measurement value of the downstream NOx sensor, determines whether ammonia leakage exists in the exhaust gas.

5. The method of claim 1, wherein, Before determining whether the raw exhaust NOx of the engine is in a stable state, further comprising: Determining whether the operating state and the aftertreatment state of the engine are in a stable state, and when the operating state and the aftertreatment state of the engine are in a stable state, continuing to execute the subsequent process.

6. An engine exhaust ammonia slip detection device characterized by, The engine exhaust ammonia leakage detection device for determining whether ammonia leakage exists in the exhaust gas by the engine exhaust ammonia leakage detection method of any one of claims 1-5, comprising: A raw exhaust state determination unit for determining whether the raw exhaust NOx of the engine is in a stable state; A raw exhaust NOx adjustment unit for adjusting the raw exhaust NOx of the engine to a target value when the raw exhaust NOx is in a stable state; A leakage determination unit for obtaining the measurement values of the upstream NOx sensor and the downstream NOx sensor during the process of adjusting the raw exhaust NOx to a target value, and determining whether ammonia leakage exists in the exhaust gas based on the measurement values of the upstream NOx sensor and the downstream NOx sensor.

7. An engine control system characterized by comprising: Comprising a memory and a processor; The memory is used to store programs; The processor is used to execute the programs to realize the steps of the engine exhaust ammonia leakage detection method of any one of claims 1-5.

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