Signal detection method and device of nitrogen oxide sensor, nitrogen oxide sensor

Abstract

The application discloses a nitrogen oxide sensor signal detection method and device and a nitrogen oxide sensor. The method comprises the following steps: obtaining a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations after determining that an engine is started, wherein the first nitrogen oxide concentration is simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, the second nitrogen oxide concentration is calculated by an electronic controller of the engine, and the nitrogen oxide sensor is used for detecting the concentration of nitrogen oxide in exhaust gas emitted by the engine; determining a correlation value and a characteristic value of the plurality of first nitrogen oxide concentrations and the plurality of second nitrogen oxide concentrations; and determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value. The application solves the technical problem that the related art cannot effectively determine whether the NOx sensor signal is tampered with, thereby reducing the reliability of the engine.

Description

Technical Field

[0001] This invention relates to the field of engine fault detection technology, and more specifically, to a signal detection method and device for a nitrogen oxide sensor, and a nitrogen oxide sensor. Background Technology

[0002] Due to the NOx emission limits imposed on engines, China VI emission standard engines must be equipped with a selective catalytic reduction (SCR) system and have increased urea injection, significantly increasing engine operating costs. Currently, various NOx signal simulators on the market simulate the NOx signals sent from real NOx sensors to the engine control unit (ECU). This allows for manual control of the NOx signals received by the ECU, thereby reducing urea consumption and lowering the rate of fault reports, ultimately reducing engine operating and maintenance costs.

[0003] The above method specifically compares the NOx value obtained by the ECU through standard messages with the model value calculated internally by the ECU in real time. When the deviation between the two values ​​exceeds a certain value, it is determined that the NOx sensor has malfunctioned.

[0004] However, the above methods cannot distinguish whether the NOx sensor has been tampered with or is malfunctioning. Furthermore, if the NOx simulated value calculated by the NOx signal simulator is consistent with the NOx model value calculated by the ECU, it is impossible to accurately and effectively determine whether the NOx sensor is malfunctioning, and the reliability is also relatively low.

[0005] There is currently no effective solution to the problem that the aforementioned technologies cannot effectively determine whether NOx sensor signals have been tampered with, leading to low engine reliability. Summary of the Invention

[0006] This invention provides a signal detection method and apparatus for a nitrogen oxide sensor, as well as a nitrogen oxide sensor, to at least solve the technical problem in related technologies where it is impossible to effectively determine whether the NOx sensor signal has been tampered with, resulting in low engine reliability.

[0007] According to one aspect of the present invention, a signal detection method for a nitrogen oxide sensor is provided. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in exhaust gas emitted by an engine. The method includes: after determining that the engine has started, acquiring a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations, wherein the first nitrogen oxide concentrations are simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentrations are calculated by the engine's electronic controller. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration; determining a correlation value and a characteristic value of the plurality of first nitrogen oxide concentrations and the plurality of second nitrogen oxide concentrations; and determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value.

[0008] Optionally, obtaining multiple first nitrogen oxide concentrations includes: when it is determined that the engine meets preset operating conditions, controlling the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller starting from the current moment; intercepting the nitrogen oxide signal using the nitrogen oxide signal simulator, and simulating the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; receiving the nitrogen oxide simulated signal sent by the nitrogen oxide signal simulator, and parsing it to obtain the first nitrogen oxide concentration.

[0009] Optionally, obtaining multiple second nitrogen oxide concentrations includes: generating the second nitrogen oxide concentration starting from the current moment when it is determined that the engine meets the preset operating conditions.

[0010] Optionally, the preset operating conditions include: the engine's running time exceeds a first predetermined time since the last signal detection, the vehicle's mileage exceeds a predetermined mileage, the engine's speed is within a predetermined speed range, the engine's fuel injection quantity is within a predetermined injection range, and the engine is not in a reverse towing condition for more than a second predetermined time.

[0011] Optionally, the signal detection method of the nitrogen oxide sensor further includes: starting timing from the current moment, storing the first nitrogen oxide concentration and the second nitrogen oxide concentration in a predetermined storage medium, and stopping the storage operation when the timing duration reaches a third predetermined duration.

[0012] Optionally, the signal detection method of the nitrogen oxide sensor further includes: stopping the interception operation of the nitrogen oxide signal simulator when the timing duration reaches a third predetermined duration.

[0013] Optionally, determining the correlation value of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations includes: obtaining the covariance of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; obtaining the variance product of the variances of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; and determining the ratio of the covariance to the variance product as the correlation value.

[0014] Optionally, the characteristic value includes at least one of the following: the absolute value of the difference between the maximum value of a plurality of first nitrogen oxide concentrations and the maximum value of a plurality of second nitrogen oxide concentrations, the absolute value of the difference between the minimum value of a plurality of first nitrogen oxide concentrations and the minimum value of a plurality of second nitrogen oxide concentrations, the average value of a plurality of first nitrogen oxide concentrations, and the average value of a plurality of second nitrogen oxide concentrations.

[0015] Optionally, determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the feature value includes: if the correlation value is higher than a predetermined limit and all feature values ​​are lower than the corresponding feature value limit, then the nitrogen oxide signal is determined to be normal; if the correlation value is not higher than the predetermined limit, or any one of the feature values ​​is lower than the corresponding feature value limit, then the nitrogen oxide signal is determined to be abnormal.

[0016] According to another aspect of the present invention, a signal detection device for a nitrogen oxide sensor is also provided. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by an engine. The device includes: an acquisition unit, configured to acquire a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations after determining that the engine has started, wherein the first nitrogen oxide concentrations are simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentrations are calculated by the engine's electronic controller; the nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration; a first determination unit, configured to determine a correlation value and a characteristic value of the plurality of first nitrogen oxide concentrations and the plurality of second nitrogen oxide concentrations; and a second determination unit, configured to determine whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value.

[0017] Optionally, the acquisition unit includes: a sending module, configured to control the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller starting from the current moment when it is determined that the engine meets the preset operating conditions; a simulation module, configured to intercept the nitrogen oxide signal using the nitrogen oxide signal simulator and simulate the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; and a parsing module, configured to receive the nitrogen oxide simulation signal sent by the nitrogen oxide signal simulator and parse it to obtain the first nitrogen oxide concentration.

[0018] Optionally, the acquisition unit includes: a generation module, configured to generate the second nitrogen oxide concentration starting from the current moment when it is determined that the engine meets the preset operating conditions.

[0019] Optionally, the preset operating conditions include: the engine's running time exceeds a first predetermined time since the last signal detection, the vehicle's mileage exceeds a predetermined mileage, the engine's speed is within a predetermined speed range, the engine's fuel injection quantity is within a predetermined injection range, and the engine is not in a reverse towing condition for more than a second predetermined time.

[0020] Optionally, the signal detection device of the nitrogen oxide sensor further includes: a processing unit, configured to start timing from the current moment, store the first nitrogen oxide concentration and the second nitrogen oxide concentration in a predetermined storage medium, and stop the storage operation when the timing duration reaches a third predetermined duration.

[0021] Optionally, the signal detection device of the nitrogen oxide sensor further includes a stop unit, used to stop the interception operation of the nitrogen oxide signal simulator when the timing duration reaches a third predetermined duration.

[0022] Optionally, the first determining unit includes: a first acquiring module, configured to acquire the covariance of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; a second acquiring module, configured to acquire the variance product of the variances of the plurality of first nitrogen oxide concentrations and the variances of the plurality of second nitrogen oxide concentrations; and a first determining module, configured to determine that the ratio of the covariance to the variance product is the correlation value.

[0023] Optionally, the characteristic value includes at least one of the following: the absolute value of the difference between the maximum value of a plurality of first nitrogen oxide concentrations and the maximum value of a plurality of second nitrogen oxide concentrations, the absolute value of the difference between the minimum value of a plurality of first nitrogen oxide concentrations and the minimum value of a plurality of second nitrogen oxide concentrations, the average value of a plurality of first nitrogen oxide concentrations, and the average value of a plurality of second nitrogen oxide concentrations.

[0024] Optionally, the second determining unit includes: a second determining module, configured to determine that the nitrogen oxide signal is not abnormal when the correlation value is higher than a predetermined limit and all the feature values ​​are lower than the corresponding feature value limit; and a third determining module, configured to determine that the nitrogen oxide signal is abnormal when the correlation value is not higher than the predetermined limit or any one of the feature values ​​is lower than the corresponding feature value limit.

[0025] According to another aspect of the present invention, a nitrogen oxide sensor is also provided, wherein the nitrogen oxide sensor uses the signal detection method of the nitrogen oxide sensor described in any one of the above embodiments.

[0026] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein the program executes any one of the signal detection methods for a nitrogen oxide sensor described above.

[0027] According to another aspect of the present invention, a processor is also provided, the processor being configured to run a program, wherein the program, when running, executes the signal detection method of the nitrogen oxide sensor described in any one of the foregoing embodiments.

[0028] In this embodiment of the invention, after determining that the engine has started, multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations are acquired. The first nitrogen oxide concentration is simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentration is calculated by the engine's electronic controller. A nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine. The nitrogen oxide signal carries the nitrogen oxide concentration. The correlation values ​​and characteristic values ​​of the multiple first and second nitrogen oxide concentrations are determined. Based on the correlation values ​​and characteristic values, it is determined whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal. The signal detection method for the nitrogen oxide sensor provided by this embodiment of the invention achieves the goal of accurately detecting whether the nitrogen oxide signal has been tampered with, thereby improving the technical effect of engine reliability. This solves the technical problem in related technologies where it is impossible to effectively determine whether the NOx sensor signal has been tampered with, leading to low engine reliability. Attached Figure Description

[0029] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0030] Figure 1 This is a flowchart of a signal detection method for a nitrogen oxide sensor according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the NOx simulator simulation process according to an embodiment of the present invention;

[0032] Figure 3 This is a flowchart of an optional signal detection method for a nitrogen oxide sensor according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of a signal detection device for a nitrogen oxide sensor according to the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention 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 so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a 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.

[0036] For ease of description, some of the nouns or terms appearing in the embodiments of the present invention will be explained below.

[0037] Nitrogen oxide sensor: also known as NOx sensor, is used to measure NOx pollutants in engine exhaust.

[0038] SCR system: Selective Catalytic Reduction, a device that reduces NOx content in exhaust gas by injecting urea into the exhaust pipe.

[0039] SAE J1939: A recommended standard from the Society of Automotive Engineers (SAE) for providing a standard architecture for communication between electronic components in medium and heavy-duty road vehicles.

[0040] AT1 IG1: After Treatment 1 Intake Gas 1, the NOx sensor transmits a J1939 standard message to the ECU indicating the NOx concentration at the SCR inlet.

[0041] Tampering: refers to shutting down, adjusting or modifying a vehicle's emissions or powertrain systems, including software or other logic control units, resulting in a deterioration in the vehicle's emissions performance.

[0042] Example 1

[0043] According to an embodiment of the present invention, a method embodiment for signal detection of a nitrogen oxide sensor is provided. It should be noted that the nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by an engine. 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. 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.

[0044] Figure 1 This is a flowchart of a signal detection method for a nitrogen oxide sensor according to an embodiment of the present invention, such as... Figure 1 As shown, the signal detection method of this nitrogen oxide sensor includes the following steps:

[0045] Step S102: After determining that the engine has started, multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations are acquired. The first nitrogen oxide concentration is simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentration is calculated by the engine's electronic controller. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration.

[0046] Optionally, the aforementioned first nitrogen oxide concentration value is obtained by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal. That is, during the process of the nitrogen oxide sensor sending a nitrogen oxide signal to the engine's ECU, the nitrogen oxide signal simulator intercepts the nitrogen oxide signal, adjusts the nitrogen oxide signal, and then simulates the first nitrogen oxide concentration based on the adjusted nitrogen oxide signal.

[0047] in, Figure 2 This is a schematic diagram of the NOx simulator simulation process according to an embodiment of the present invention, as shown below. Figure 2As shown, the general principle of a NOx signal simulator (i.e., nitrogen oxide signal simulator) is as follows: The message value (such as AT1 IG1) sent by the NOx sensor to the engine ECU according to a standard protocol (such as SAE J1939) is masked by the NOx signal simulator. The NOx signal simulator uses this standard message (such as AT1 IG1) to send the simulated NOx value calculated by itself using part of the engine's message information (this part of the information is sent by the engine ECU through a standard protocol) to the engine ECU, thereby achieving the purpose of tampering with the NOx signal.

[0048] Optionally, the aforementioned second nitrogen oxide concentration value is calculated internally by the ECU.

[0049] Step S104: Determine the correlation values ​​and characteristic values ​​of multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations.

[0050] In this embodiment, the correlation values ​​of multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations, as well as the characteristic values, can be calculated to determine whether the nitrogen oxide signal has been tampered with.

[0051] Step S106: Determine whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value.

[0052] Optionally, the anomaly here could be whether the nitrogen oxide signal has been tampered with.

[0053] As can be seen from the above analysis, in the embodiments of the present invention, multiple first nitrogen oxide concentrations can be simulated using a nitrogen oxide signal simulator, and multiple second nitrogen oxide concentrations can be calculated using the engine ECU. Then, based on the correlation values ​​and characteristic values ​​of the first and second nitrogen oxide concentrations, it can be determined whether the nitrogen oxide signal has been tampered with, thereby achieving the purpose of accurate detection of whether the nitrogen oxide signal has been tampered with, and achieving the technical effect of improving the reliability of the engine.

[0054] Therefore, the signal detection method for the nitrogen oxide sensor provided in this embodiment of the invention solves the technical problem in the related art that it is impossible to effectively determine whether the NOx sensor signal has been tampered with, resulting in low engine reliability.

[0055] According to the above embodiments of the present invention, obtaining multiple first nitrogen oxide concentrations includes: when it is determined that the engine meets preset operating conditions, controlling the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller from the current moment; intercepting the nitrogen oxide signal using a nitrogen oxide signal simulator, and simulating the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; receiving the nitrogen oxide simulation signal sent by the nitrogen oxide signal simulator, and parsing to obtain the first nitrogen oxide concentration.

[0056] In this embodiment, when the engine meets preset operating conditions (for example, the engine's running time exceeds a first predetermined time after the last signal detection, the vehicle's mileage exceeds a predetermined mileage, the engine speed is within a predetermined speed range, the engine's fuel injection quantity is within a predetermined injection range, and the engine is not in reverse towing condition for more than a second predetermined time), the NOx sensor electronic controller is controlled to send a NOx signal from the current moment. During this process, the NOx signal is intercepted using a NOx signal simulator, and the first NOx concentration is simulated based on the NOx information carried in the NOx signal.

[0057] According to the above embodiments of the present invention, obtaining multiple second nitrogen oxide concentrations includes: when it is determined that the engine meets preset operating conditions, generating second nitrogen oxide concentrations starting from the current moment.

[0058] In this embodiment, when the engine meets preset operating conditions (for example, the engine's running time exceeds a first predetermined time after the last signal detection, the vehicle's mileage exceeds a predetermined mileage, the engine speed is within a predetermined speed range, the engine's fuel injection quantity is within a predetermined injection range, and the engine is not in reverse towing condition for more than a second predetermined time), the second nitrogen oxide concentration is generated from the current moment.

[0059] According to the above embodiments of the present invention, the preset operating conditions include: the engine running time exceeds a first predetermined time after the last signal detection is completed, the mileage of the vehicle where the engine is located exceeds a predetermined mileage, the engine speed is within a predetermined speed range, the engine fuel injection quantity is within a predetermined injection range, and the engine is not in a reverse towing condition for more than a second predetermined time.

[0060] The aforementioned preset operating conditions may include, but are not limited to: the NOx sensor circuit is normal and there is no electrical fault, and there is no fault indicating that the NOx sensor measurement value is unreliable.

[0061] According to the above embodiments of the present invention, the signal detection method of the nitrogen oxide sensor may further include: starting timing from the current moment, storing the first nitrogen oxide concentration and the second nitrogen oxide concentration in a predetermined storage medium, and stopping the storage operation when the timing duration obtained reaches a third predetermined duration.

[0062] In this embodiment, the NOx model value calculated in the ECU and the NOx value sent in the message can be collected in real time and stored in array X respectively. n Y n (e.g., n=10). When the timer reaches its limit (this limit is determined by the number of elements n stored in the array), the storage array X... n Y nStorage is stopped, and some J1939 messages sent by the engine ECU are switched to normal values.

[0063] According to the above embodiments of the present invention, the signal detection method of the nitrogen oxide sensor may further include: stopping the interception operation of the nitrogen oxide signal simulator when the timing duration reaches a third predetermined duration.

[0064] In this embodiment, when the timer reaches its limit (which is determined by the number of elements n stored in the array), the storage array X... n Y n Storage is stopped, and some J1939 messages sent by the engine ECU are switched to normal values.

[0065] According to the above embodiments of the present invention, determining the correlation value of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations may include: obtaining the covariance of the plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; obtaining the variance product of the variances of the plurality of first nitrogen oxide concentrations and the variances of the plurality of second nitrogen oxide concentrations; and determining the ratio of the covariance to the variance product as the correlation value.

[0066] In this embodiment, the correlation values ​​between the multiple first nitrogen oxide concentrations and the multiple second nitrogen oxide concentrations can be calculated using the following formula: Where Cov(X,Y)=E*,XE(X)-,YE(Y)-+ is the covariance of array X (multiple second nitrogen oxide concentrations) and array Y (multiple first nitrogen oxide concentrations), and D(X) and D(Y) are the variances of array X and Y respectively.

[0067] According to the above embodiments of the present invention, the feature value includes at least one of the following: the absolute value of the difference between the maximum value of a plurality of first nitrogen oxide concentrations and the maximum value of a plurality of second nitrogen oxide concentrations, the absolute value of the difference between the minimum value of a plurality of first nitrogen oxide concentrations and the minimum value of a plurality of second nitrogen oxide concentrations, the average value of a plurality of first nitrogen oxide concentrations, and the average value of a plurality of second nitrogen oxide concentrations.

[0068] According to the above embodiments of the present invention, determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the feature value includes: if the correlation value is higher than a predetermined limit and all feature values ​​are lower than the corresponding feature value limit, then it is determined that the nitrogen oxide signal is not abnormal; if the correlation value is not higher than the predetermined limit, or any one of the feature values ​​is lower than the corresponding feature value limit, then it is determined that the nitrogen oxide signal is abnormal.

[0069] In this embodiment, the predetermined limit and feature value restriction can be determined based on the required accuracy of the nitrogen oxide signal. For example, the correlation value is generally set between 0 and 1. The smaller the predetermined limit, the greater the correlation between the two nitrogen oxide signals, resulting in a more accurate nitrogen oxide signal and preventing system misjudgment. In this embodiment of the invention, the accuracy requirement can be set according to the actual working conditions; for example, it can be set to 0.7.

[0070] Similarly, the smaller the above feature value limit, the higher the requirement for accuracy. When the above feature value limit is met, it means that the two nitrogen oxide signals are closer and there is no abnormality in the nitrogen oxide signal.

[0071] When X max With Y max The absolute value of the difference, X min With Y min The absolute value of the difference, X e With Y e The absolute values ​​of the differences are all less than the corresponding limits, and array X n Y n If the correlation value of the data is also higher than the limit (e.g., 0.7), the NOx sensor message signal is considered normal; otherwise, a fault indicating that the NOx sensor message signal has been tampered with is reported.

[0072] Figure 3 This is a flowchart of an optional signal detection method for a nitrogen oxide sensor according to an embodiment of the present invention, such as... Figure 3 As shown, the ECU is powered on and the engine starts normally. At this time, it is determined whether the NOx sensor anti-tamper monitoring release conditions (i.e., preset operating conditions) are met. These anti-tamper monitoring release conditions include, but are not limited to: 1. The engine running time since the last NOx sensor anti-tamper monitoring exceeded the limit (e.g., 100 hours) or the vehicle mileage exceeded the limit (e.g., 5000 km); 2. The SCR upstream temperature is within a certain range (e.g., 190-350℃); 3. The engine speed is within a certain range (e.g., 800-1500 r / m); 4. The engine fuel injection quantity is within a certain range (e.g., 60-180 mg / hub); 5. The engine has not been in reverse dragging condition for a certain period of time (e.g., 300 seconds); 6. The NOx sensor circuit is normal and there are no electrical faults; 7. There are no unreliable NOx sensor measurement values. To improve the accuracy of nitrogen oxide signal detection, once the above conditions are met, the engine ECU sends a set value for some J1939 message values ​​(such as engine load rate), and simultaneously a timer starts counting down, collecting the NOx model value calculated in the ECU and the NOx value sent from the message in real time, storing them in array X. n Y n(e.g., n=10). When the timer reaches its limit (this limit is determined by the number of elements n stored in the array), the storage array X... n Y n Storage is stopped, and some J1939 messages sent by the engine ECU are switched to normal values. At this point, array X is calculated. n Y n The correlation value ρ of the data XY array X n The maximum value X max Minimum value X min and mean X e array Y n The maximum value Y max Minimum value Y min and mean Y e When X max With Y max The absolute value of the difference, X min With Y min The absolute value of the difference, X e With Y e The absolute values ​​of the differences are all less than the corresponding limits, and array X n Y n If the correlation value of the data is also higher than the limit (e.g., 0.7), the NOx sensor message signal is considered normal; otherwise, a fault indicating that the NOx sensor message signal has been tampered with is reported.

[0073] The signal detection method for nitrogen oxide sensors provided in this invention actively adjusts a portion of the message information that the NOx simulator may use to calculate the simulated NOx value. The difference between the NOx value obtained by the ECU through the standard message after this adjustment and the NOx model value calculated internally by the ECU is compared to determine whether the NOx sensor signal has been tampered with. Furthermore, an array is constructed by collecting the message NOx value and the NOx model value. When the maximum, minimum, and mean values ​​of the two sets of data are not significantly different, the correlation values ​​between the two sets of data are compared. This active monitoring scheme avoids the influence of factors such as engine operating conditions and sensor accuracy deviations, thus improving the reliability of the monitoring strategy.

[0074] Therefore, in this embodiment of the invention, the NOx simulator may actively adjust some message information (such as aftertreatment temperature, exhaust mass flow rate, engine speed, fuel injection quantity, engine load rate, etc.) used to calculate the NOx simulation value. By comparing the difference (correlation) between the NOx value obtained by the ECU through the standard message after the adjustment of this part of the information and the NOx model value calculated internally by the ECU, it is determined whether the NOx sensor signal has been tampered with.

[0075] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0077] Example 2

[0078] According to an embodiment of the present invention, a signal detection device for a nitrogen oxide sensor is also provided for implementing the above-described signal detection method for a nitrogen oxide sensor. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in exhaust gas emitted by an engine. Figure 4 This is a schematic diagram of a signal detection device for a nitrogen oxide sensor according to the present invention, as shown below. Figure 4 As shown, the device includes: an acquisition unit 41, a first determination unit 43, and a second determination unit 45.

[0079] The acquisition unit 41 is used to acquire multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations after determining that the engine has started. The first nitrogen oxide concentration is simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentration is calculated by the engine's electronic controller. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration.

[0080] The first determining unit 43 is used to determine the correlation values ​​and characteristic values ​​of multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations.

[0081] The second determining unit 45 is used to determine whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value.

[0082] It should be noted here that the above-mentioned acquisition unit 41, first determination unit 43 and second determination unit 45 correspond to steps S102 to S106 in embodiment 1. The three modules and the corresponding steps implement the same instances and application scenarios, but are not limited to the content disclosed in embodiment 1 above.

[0083] As can be seen from the above, in the scheme described in Embodiment 2 of this application, the acquisition unit can acquire multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations after determining that the engine has started. The first nitrogen oxide concentration is simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentration is calculated by the engine's electronic controller. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration. Then, the first determination unit determines the correlation values ​​and characteristic values ​​of the multiple first nitrogen oxide concentrations and the multiple second nitrogen oxide concentrations. Finally, the second determination unit determines whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation values ​​and characteristic values. Through the signal detection device for the nitrogen oxide sensor provided by this embodiment of the invention, the purpose of accurately detecting whether the nitrogen oxide signal has been tampered with is achieved, thus improving the technical effect of engine reliability. This solves the technical problem in related technologies where it is impossible to effectively determine whether the NOx sensor signal has been tampered with, leading to low engine reliability.

[0084] Optionally, the acquisition unit includes: a sending module, configured to control the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller starting from the current moment when it is determined that the engine meets the preset operating conditions; a simulation module, configured to intercept the nitrogen oxide signal using a nitrogen oxide signal simulator and simulate the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; and a parsing module, configured to receive the nitrogen oxide simulation signal sent by the nitrogen oxide signal simulator and parse it to obtain the first nitrogen oxide concentration.

[0085] Optionally, the acquisition unit includes: a generation module, used to generate a second nitrogen oxide concentration starting from the current moment when it is determined that the engine meets preset operating conditions.

[0086] Optionally, the preset operating conditions include: the engine running time exceeds a first predetermined time since the last signal detection, the mileage of the vehicle where the engine is located exceeds a predetermined mileage, the engine speed is within a predetermined speed range, the engine fuel injection quantity is within a predetermined injection range, and the engine is not in reverse towing condition for more than a second predetermined time.

[0087] Optionally, the signal detection device of the nitrogen oxide sensor further includes: a processing unit, configured to start timing from the current moment, store the first nitrogen oxide concentration and the second nitrogen oxide concentration in a predetermined storage medium, and stop the storage operation when the timing duration reaches a third predetermined duration.

[0088] Optionally, the signal detection device of the nitrogen oxide sensor further includes a stop unit, used to stop the interception operation of the nitrogen oxide signal simulator when the timing duration reaches a third predetermined duration.

[0089] Optionally, the first determining unit includes: a first acquiring module, configured to acquire the covariance of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; a second acquiring module, configured to acquire the variance product of the variances of the plurality of first nitrogen oxide concentrations and the variances of the plurality of second nitrogen oxide concentrations; and a first determining module, configured to determine that the ratio of the covariance to the variance product is a correlation value.

[0090] Optionally, the characteristic value includes at least one of the following: the absolute value of the difference between the maximum value of a plurality of first nitrogen oxide concentrations and the maximum value of a plurality of second nitrogen oxide concentrations, the absolute value of the difference between the minimum value of a plurality of first nitrogen oxide concentrations and the minimum value of a plurality of second nitrogen oxide concentrations, the average value of a plurality of first nitrogen oxide concentrations, and the average value of a plurality of second nitrogen oxide concentrations.

[0091] Optionally, the second determining unit includes: a second determining module, used to determine that the nitrogen oxide signal is not abnormal when the correlation value is higher than a predetermined limit and all feature values ​​are lower than the corresponding feature value limit; and a third determining module, used to determine that the nitrogen oxide signal is abnormal when the correlation value is not higher than the predetermined limit or any one of the feature values ​​is lower than the corresponding feature value limit.

[0092] Example 3

[0093] According to another aspect of the present invention, a nitrogen oxide sensor is also provided, wherein the nitrogen oxide sensor uses the signal detection method of the nitrogen oxide sensor described above.

[0094] Example 4

[0095] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein any one of the program executions is a signal detection method for a nitrogen oxide sensor.

[0096] Optionally, in this embodiment, the computer-readable storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any communication device in a group of communication devices.

[0097] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: after determining that the engine has started, acquiring multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations, wherein the first nitrogen oxide concentrations are simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, the second nitrogen oxide concentrations are calculated by the engine's electronic controller, a nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration; determining the correlation values ​​and characteristic values ​​of the multiple first nitrogen oxide concentrations and the multiple second nitrogen oxide concentrations; and determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation values ​​and characteristic values.

[0098] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when it is determined that the engine meets the preset operating conditions, starting from the current moment, controlling the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller; using a nitrogen oxide signal simulator to intercept the nitrogen oxide signal, and simulating the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; receiving the nitrogen oxide simulated signal sent by the nitrogen oxide signal simulator, and parsing to obtain the first nitrogen oxide concentration.

[0099] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when it is determined that the engine meets preset operating conditions, a second nitrogen oxide concentration is generated starting from the current moment.

[0100] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: starting timing from the current moment, storing the first nitrogen oxide concentration and the second nitrogen oxide concentration to a predetermined storage medium, and stopping the storage operation when the timing duration reaches a third predetermined duration.

[0101] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: stopping the interception operation of the nitrogen oxide signal simulator when the timing duration reaches a third predetermined duration.

[0102] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: obtaining the covariance of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; obtaining the variance product of the variances of the plurality of first nitrogen oxide concentrations and the variances of the plurality of second nitrogen oxide concentrations; and determining that the ratio of the covariance to the variance product is a correlation value.

[0103] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: if the correlation value is higher than a predetermined limit and all feature values ​​are lower than the corresponding feature value limit, then it is determined that the nitrogen oxide signal is not abnormal; if the correlation value is not higher than the predetermined limit, or any one of the feature values ​​is lower than the corresponding feature value limit, then it is determined that the nitrogen oxide signal is abnormal.

[0104] Example 5

[0105] According to another aspect of the present invention, a processor is also provided, which is used to run a program, wherein the program executes the signal detection method of the nitrogen oxide sensor described above.

[0106] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0107] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0108] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0109] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0110] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0111] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0112] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A signal detection method for a nitrogen oxide sensor, wherein the nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in exhaust gas emitted by an engine, characterized in that, include: After the engine is started, multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations are acquired. The first nitrogen oxide concentrations are simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentrations are calculated by the engine's electronic controller. The nitrogen oxide signal carries the nitrogen oxide concentration. Determine the correlation values ​​and characteristic values ​​of multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations; Based on the correlation value and the characteristic value, it is determined whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal. Obtaining multiple first nitrogen oxide concentrations includes: when it is determined that the engine meets preset operating conditions, controlling the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller starting from the current moment; using the nitrogen oxide signal simulator to intercept the nitrogen oxide signal, and simulating the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; receiving the nitrogen oxide simulated signal sent by the nitrogen oxide signal simulator, and parsing it to obtain the first nitrogen oxide concentration.

2. The signal detection method for the nitrogen oxide sensor according to claim 1, characterized in that, Obtain multiple second nitrogen oxide concentrations, including: When it is determined that the engine meets the preset operating conditions, the second nitrogen oxide concentration is generated starting from the current moment.

3. The signal detection method for the nitrogen oxide sensor according to claim 2, characterized in that, The preset operating conditions include: the engine's running time exceeds a first predetermined time since the last signal detection, the vehicle's mileage exceeds a predetermined mileage, the engine's speed is within a predetermined speed range, the engine's fuel injection quantity is within a predetermined injection range, and the engine is not in a reverse towing condition for more than a second predetermined time.

4. The signal detection method for the nitrogen oxide sensor according to claim 2, characterized in that, Also includes: Starting from the current moment, the first nitrogen oxide concentration and the second nitrogen oxide concentration are stored in a predetermined storage medium, and the storage operation stops when the timed duration reaches a third predetermined duration.

5. The signal detection method for the nitrogen oxide sensor according to claim 4, characterized in that, Also includes: When the timing duration reaches the third predetermined duration, the interception operation of the nitrogen oxide signal simulator is stopped.

6. The signal detection method for the nitrogen oxide sensor according to claim 1, characterized in that, Determining the correlation values ​​between multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations, including: Obtain the covariance of multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations; Obtain the product of the variances of the multiple first nitrogen oxide concentrations and the variances of the multiple second nitrogen oxide concentrations; The ratio of the covariance to the product of the variance is determined as the correlation value.

7. The signal detection method for the nitrogen oxide sensor according to claim 1, characterized in that, The characteristic value includes at least one of the following: the absolute value of the difference between the maximum value of a plurality of first nitrogen oxide concentrations and the maximum value of a plurality of second nitrogen oxide concentrations, the absolute value of the difference between the minimum value of a plurality of first nitrogen oxide concentrations and the minimum value of a plurality of second nitrogen oxide concentrations, the average value of a plurality of first nitrogen oxide concentrations, and the average value of a plurality of second nitrogen oxide concentrations.

8. The signal detection method for the nitrogen oxide sensor according to any one of claims 1 to 7, characterized in that, Determining whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal based on the correlation value and the characteristic value includes: If the correlation value is higher than a predetermined limit and all the feature values ​​are lower than the corresponding feature value limits, then it is determined that the nitrogen oxide signal is not abnormal. If the correlation value is not higher than a predetermined limit, or if any of the characteristic values ​​is less than the corresponding characteristic value limit, then the nitrogen oxide signal is determined to be abnormal.

9. A signal detection device for a nitrogen oxide sensor, wherein the nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in exhaust gas emitted by an engine, characterized in that, include: The acquisition unit is used to acquire multiple first nitrogen oxide concentrations and multiple second nitrogen oxide concentrations after determining that the engine has started. The first nitrogen oxide concentrations are simulated by a nitrogen oxide signal simulator based on an adjusted nitrogen oxide signal, and the second nitrogen oxide concentrations are calculated by the engine's electronic controller. The nitrogen oxide sensor is used to detect the concentration of nitrogen oxides in the exhaust gas emitted by the engine, and the nitrogen oxide signal carries the nitrogen oxide concentration. The first determining unit is used to determine the correlation values ​​and characteristic values ​​of a plurality of first nitrogen oxide concentrations and a plurality of second nitrogen oxide concentrations; The second determining unit is used to determine, based on the correlation value and the feature value, whether the nitrogen oxide signal sent by the nitrogen oxide sensor to the engine is abnormal. The acquisition unit includes: a sending module, configured to control the nitrogen oxide sensor to send a nitrogen oxide signal to the electronic controller starting from the current moment when it is determined that the engine meets the preset operating conditions; a simulation module, configured to intercept the nitrogen oxide signal using the nitrogen oxide signal simulator and simulate the first nitrogen oxide concentration based on the nitrogen oxide information carried in the nitrogen oxide signal; and a parsing module, configured to receive the nitrogen oxide simulation signal sent by the nitrogen oxide signal simulator and parse it to obtain the first nitrogen oxide concentration.

10. A nitrogen oxide sensor, characterized in that, The nitrogen oxide sensor uses the signal detection method of the nitrogen oxide sensor according to any one of claims 1 to 8.

Images