Fault diagnosis method and device for turbine front pressure sensor and vehicle

Abstract

The invention discloses a fault diagnosis method and device for a turbine front pressure sensor and a vehicle. Fault diagnosis can be carried out on the turbine front pressure sensor in the operation process. The turbine front pressure sensor is used for measuring the pressure of a turbine front exhaust manifold of the engine; the fault diagnosis method for the turbine front pressure sensor comprises the steps that when the operation condition of an engine meets a preset condition, the air inflow of the engine and the measured value of the turbine front pressure sensor are obtained; calculating correlation based on the air inflow of the engine and the measured value of the turbine front pressure sensor; wherein the correlation represents the correlation between the change degree of the vortex front pressure and the change degree of the air inflow; when the correlation is smaller than or equal to a preset threshold value, it is determined that the turbine front pressure sensor breaks down.

Description

Technical Field

[0001] The present application relates to the technical field of engines, and particularly to a method and device for diagnosing faults of a pre-turbine pressure sensor and a vehicle. Background Art

[0002] With the increasingly stringent emission technologies, many engines use pre-turbine pressure sensors to measure the pre-turbine pressure of the engine, and then control the exhaust throttle valve of the engine. However, because there is water vapor in the exhaust gas after the engine combustion, the water vapor in the pressure-taking pipe will freeze and block the pressure-taking pipe in a cold low-temperature environment, resulting in the pre-turbine pressure sensor being unable to measure the exhaust pressure in front of the turbine. At present, the pre-turbine pressure sensor can only diagnose electrical connection faults of the sensor and static pressure credibility diagnosis. If the air intake pipe freezes during the operation of the whole vehicle in a low-temperature environment, it cannot be diagnosed, and it is necessary to wait until the vehicle stops to determine the fault. Therefore, the pre-turbine pressure sensor cannot achieve fast and accurate fault determination in dynamic working conditions, which is likely to affect the engine performance. Summary of the Invention

[0003] In order to solve the above technical problems, the present application is proposed. Embodiments of the present application provide a method and device for diagnosing faults of a pre-turbine pressure sensor and a vehicle, which can diagnose faults of the pre-turbine pressure sensor during operation.

[0004] According to a first aspect of the present application, there is provided a method for diagnosing faults of a pre-turbine pressure sensor, where the pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine; wherein, the method for diagnosing faults of the pre-turbine pressure sensor includes: when the operating condition of the engine meets a preset condition, obtaining the intake air volume of the engine and the measured value of the pre-turbine pressure sensor; calculating a correlation based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor; wherein, the correlation characterizes the correlation between the change degree of the pre-turbine pressure and the change degree of the intake air volume; when the correlation is less than or equal to a preset threshold, determining that the pre-turbine pressure sensor fails.

[0005] As a possible implementation manner, when the operating condition of the engine meets a preset condition, obtaining the intake air volume of the engine and the measured value of the pre-turbine pressure sensor includes: when the operating condition of the engine meets a preset condition, recording the intake air volume of the engine as first data every preset step length to obtain a first array; when the operating condition of the engine meets a preset condition, recording the measured value of the pre-turbine pressure sensor as second data every preset step length to obtain a second array; wherein, the measured value includes the first array and the second array.

[0006] As a possible implementation, based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, calculate the correlation, including: when the data volumes of the first array and the second array are both greater than a preset data volume, calculate the correlation based on the first array and the second array.

[0007] As a possible implementation, calculating the correlation based on the first array and the second array includes: calculating the standard deviation of the first array; calculating the standard deviation of the second array; when the standard deviation of the first array is greater than or equal to a first preset value and the standard deviation of the second array is greater than or equal to a second preset value, calculate the covariance of the first array and the second array; wherein, the covariance characterizes the direction and degree of the common change of the intake air volume of the engine and the measured value of the pre-turbine pressure sensor.

[0008] As a possible implementation, calculating the correlation based on the first array and the second array further includes: calculating the correlation according to the standard deviation of the first array, the standard deviation of the second array and the covariance; wherein, the correlation is positively correlated with the covariance and negatively correlated with the product of the standard deviation of the first array and the standard deviation of the second array.

[0009] As a possible implementation, the pre-turbine pressure sensor fault diagnosis method further includes: when it is determined that the pre-turbine pressure sensor fails, issue a control instruction; wherein, the control instruction is used to instruct the exhaust throttle valve to perform open-loop control or open the exhaust throttle valve.

[0010] As a possible implementation, when the operating condition of the engine meets a preset condition, obtain the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, including: when the engine speed is within a preset speed range, the engine fuel injection rate is within a preset fuel injection volume range, and the ambient temperature at which the engine operates is lower than a preset temperature threshold, determine whether the engine is operating in a preset working condition according to the engine operating change rate; when the engine is operating in a preset working condition, obtain the intake air volume of the engine and the measured value of the pre-turbine pressure sensor.

[0011] As a possible implementation, determining whether the engine is operating in a preset working condition according to the engine operating change rate includes: when the absolute value of the engine speed change rate is greater than a first limit value, or the absolute value of the engine fuel injection volume change rate is greater than a second limit value, or the absolute value of the intake air volume of the engine is greater than a third limit value, determine that the engine is operating in a preset working condition; wherein, the preset working condition includes an accelerating transient transition working condition and a decelerating transient transition working condition.

[0012] According to a second aspect of the present application, a fault diagnosis device for a pre-turbine pressure sensor is provided. The pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine. Wherein, the fault diagnosis device for the pre-turbine pressure sensor includes: an acquisition module, configured to acquire the intake air volume of the engine and the measured value of the pre-turbine pressure sensor when the operating condition of the engine meets a preset condition; a calculation module, configured to calculate a correlation based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor; wherein, the correlation characterizes the correlation between the change degree of the pre-turbine pressure and the change degree of the intake air volume; a determination module, configured to determine that the pre-turbine pressure sensor is faulty when the correlation is less than or equal to a preset threshold.

[0013] According to a third aspect of the present application, a vehicle is provided, including: a pre-turbine pressure sensor and an exhaust manifold; wherein, the exhaust manifold is connected to the pre-turbine pressure sensor through a pressure-taking pipe; the fault diagnosis device for the pre-turbine pressure sensor as described in the second aspect or any one of the implementation manners in the second aspect, and the fault diagnosis device for the pre-turbine pressure sensor is used to perform fault diagnosis on the pre-turbine pressure sensor.

[0014] The fault diagnosis method, device and vehicle for the pre-turbine pressure sensor provided by the present application can determine whether the pre-turbine pressure sensor is faulty when the engine is in an operating state, that is, perform diagnosis by making a correlation judgment between the pre-turbine pressure measured by the pre-turbine pressure sensor and the intake air volume of the engine. The pre-turbine pressure is a key parameter in the engine's pneumatic balance and control logic. The measured value of the pre-turbine pressure directly participates in the regulation of the intake air volume. The two form a closed-loop relationship through the thermodynamic cycle and the control system. Therefore, when the measurement of the pre-turbine pressure sensor is fault-free, the change in the pre-turbine pressure usually causes a change in the intake air volume of the engine, and there is a positive correlation between the two. If the correlation is less than or equal to the preset threshold, it means that the correlation between the pre-turbine pressure and the intake air volume becomes low, and the pre-turbine pressure sensor may have a fault such as icing. Through the correlation between the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, it is possible to accurately diagnose whether the pre-turbine pressure sensor has an icing fault during the operation of the engine, improving the real-time monitoring of the pre-turbine pressure sensor and the accuracy of fault judgment, thereby reducing the possibility of problems such as the exhaust throttle valve being uncontrollable due to the inability to judge the fault, and improving the engine performance and operation safety. Description of the Drawings

[0015] 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 required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings.

[0016] Figure 1 It is a schematic flow chart of a method for diagnosing faults in a pre-turbine pressure sensor provided by an exemplary embodiment of the present application.

[0017] Figure 2 It is a schematic diagram of the diagnostic enabling logic for diagnosing faults in a pre-turbine pressure sensor provided by an exemplary embodiment of the present application.

[0018] Figure 3 It is a schematic flow chart of a diagnostic method of a fault diagnosis device for a pre-turbine pressure sensor provided by an exemplary embodiment of the present application.

[0019] Figure 4 It is a schematic structural diagram of a fault diagnosis device for a pre-turbine pressure sensor provided by an exemplary embodiment of the present application. Detailed implementation manners

[0020] Next, exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited by the exemplary embodiments described herein.

[0021] With the increasingly stringent emission technologies, many engines use a pre-turbine pressure sensor to measure the pre-turbine pressure of the engine. The pre-turbine pressure sensor needs to be connected to the pre-turbine pressure sensor through a pressure-taking pipe from the exhaust manifold of the engine (because the temperature before the engine turbine is relatively high, far exceeding the temperature resistance range of the sensor, so a pressure pipe must be used to prevent the sensor from being burned by high temperature). The function of the pre-turbine pressure sensor is to monitor the intake pressure to help the engine control unit (ECU) adjust fuel injection and ignition timing, thereby optimizing engine performance. For example, it can be used to control the exhaust throttle valve of the engine (a valve installed on the engine to control the exhaust pressure, usually installed at the rear end of the turbocharger) to increase the exhaust temperature of the engine, so that the post-treatment can maintain a high conversion efficiency to control emissions. Therefore, it is very important to ensure the accurate measurement of the pre-turbine pressure sensor. However, because there is water vapor in the exhaust gas after engine combustion, the water vapor in the pressure-taking pipe will freeze in a cold low-temperature environment, resulting in the blockage of the pressure-taking pipe, which causes the pre-turbine pressure sensor to be unable to measure the exhaust pressure before the turbine, and then leads to abnormal control of the exhaust throttle valve, inaccurate adjustment of the intake air volume, and problems such as the destruction of the engine steady-state operating point. And currently, the diagnosis of the pre-turbine pressure sensor only includes the diagnosis of open circuit and short circuit of the sensor. The static credibility diagnosis is carried out by static comparison with the ambient pressure in the engine non-start state. If the intake pipe freezes during the operation of the whole vehicle in a low-temperature environment, the diagnosis cannot be carried out, and it is necessary to wait until the vehicle stops to determine the fault. Even if the gas in the intake pipe is not compressed when it freezes and the pressure deviation from the ambient pressure is not large, the fault cannot be determined. Before the fault is determined, the abnormal control of the exhaust throttle valve will cause the exhaust smoke density of the engine to increase abnormally, resulting in the rapid blockage of the engine post-treatment DPF (Diesel Particulate Filter) in a short time.

[0022] In order to accurately determine the failure of the pre-turbine pressure sensor during driving to ensure the engine performance, this application proposes a method, a device and a vehicle for diagnosing the failure of the pre-turbine pressure sensor. By virtue of the close relationship between the pre-turbine pressure measured by the pre-turbine pressure sensor and the engine intake air volume, the correlation between the change degrees of the engine intake air volume and the measured value of the pre-turbine pressure sensor is calculated. The engine intake air volume is mainly affected by factors such as throttle opening, engine speed, intake manifold pressure (pre-turbine pressure), and intake air temperature. In a turbocharged engine, the intervention of the turbine will significantly change the pressure in the intake manifold, thereby affecting the intake air volume. The pre-turbine pressure is a key parameter in the engine aerodynamic balance and control logic, and its measured value is directly involved in the regulation of the intake air volume. The two form a closed-loop relationship through the thermodynamic cycle and the control system. The failure of the pre-turbine pressure sensor will disrupt this balance, that is, it will affect the change of the correlation. Therefore, by calculating the correlation, it is possible to accurately diagnose whether the pre-turbine pressure sensor fails during engine operation, improving the real-time monitoring of the pre-turbine pressure sensor and the accuracy of failure judgment, and reducing the risk that the control system may cause inaccurate regulation of the intake air volume and damage the engine steady-state operating point due to the inability to accurately sense the real pressure.

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0024] Regarding the problem that it is difficult to diagnose the failure of the pre-turbine pressure sensor during operation, the following proposes a method for diagnosing the failure of the pre-turbine pressure sensor. The pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine. Figure 1 is a schematic flowchart of a method for diagnosing the failure of the pre-turbine pressure sensor provided by an exemplary embodiment of the present application. Taking Figure 1 as an example, first, when the operating condition of the engine meets the preset condition, obtain the intake air volume of the engine and the measured value of the pre-turbine pressure sensor (see Figure 1 S101). Since it is mainly to monitor whether the pre-turbine pressure sensor fails during operation, only the intake air volume and the measured value during the engine operation can be collected to reduce data redundancy. For this reason, the precondition can be set to obtain the intake air volume and the measured value only when the operating condition of the engine meets the preset condition. Based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, calculate the correlation (see Figure 1S102); wherein, the correlation characterizes the correlation between the change degree of the pressure in front of the turbine and the change degree of the intake air volume. There is usually a strong physical relationship (such as a proportional relationship) between the pressure in front of the turbine and the intake air volume under steady-state conditions. However, under transient conditions (such as acceleration and deceleration), the change degrees of the two may be inconsistent. If this correlation is significantly reduced, it may indicate a fault in the pressure sensor in front of the turbine. Based on this, by judging the correlation that characterizes the correlation between the change degree of the pressure in front of the turbine and the change degree of the intake air volume, it can be judged whether the measurement of the pressure sensor in front of the turbine is accurate, that is, whether there is a fault in the pressure sensor in front of the turbine. When the correlation is less than or equal to the preset threshold, it is determined that the pressure sensor in front of the turbine is faulty (see Figure 1 S103). If the correlation changes and is lower than the preset threshold, it is considered that the correlation between the change degree of the transient pressure in front of the turbine and the change degree of the intake air volume is reduced, and the sensor may have faults such as icing.

[0025] The following combines Figure 1 to introduce the fault diagnosis method for the pressure sensor in front of the turbine provided by the embodiments of the present application in more detail.

[0026] In S101, when the operating condition of the engine meets the preset conditions, the intake air volume of the engine and the measured value of the pressure sensor in front of the turbine are obtained.

[0027] The measured value of the pressure sensor in front of the turbine represents the measured pressure in front of the turbine. Under normal steady-state conditions, the pressure in front of the turbine and the intake air volume are usually positively correlated because: an increase in the intake air volume → an increase in the compressor pressure ratio → an increase in the combustion chamber pressure (pressure in front of the turbine), and the fuel flow is adjusted synchronously to maintain the combustion efficiency, further stabilizing the proportional relationship between the pressure in front of the turbine and the intake air volume. During transient conditions (such as acceleration), the change rate of the intake air volume is affected by the inertia of the compressor and the response delay of the control system, resulting in a short lag. The change of the pressure in front of the turbine is affected by combustion delay and turbine dynamics, and the response speeds are different. Under normal circumstances, although the two are not synchronized, the change trends should still maintain a certain dynamic coupling (such as a controllable phase difference). Therefore, obtaining the intake air volume of the engine and the measured value of the pressure sensor in front of the turbine under certain preset conditions can provide a data basis for subsequent calculation of the correlation.

[0028] To reduce data redundancy and improve data availability, in some embodiments, when the engine speed is within a preset speed range, the fuel injection rate of the engine is within a preset fuel injection amount range, and the ambient temperature at which the engine operates is lower than a preset temperature threshold, it is determined whether the engine is operating in a preset condition according to the engine's operating change rate; when the engine is operating in a preset condition, the intake air volume of the engine and the measured value of the pressure sensor before the turbine are obtained. That is to say, first, the engine speed and fuel injection amount during operation should be within a certain range to ensure the engine is in operation. And, if it is for diagnosing the special case of icing, since icing occurs in a low-temperature environment, the ambient temperature should be lower than the preset temperature threshold (for example, below 0°C) for diagnosis. After the preconditions, that is, the engine is running and the ambient temperature is low, are met, it is determined whether the engine is operating in a preset condition according to the engine's operating change rate, and when in the preset condition, the intake air volume of the engine and the measured value of the pressure sensor before the turbine are obtained.

[0029] During steady-state conditions, the changes in the intake air volume and the measured value of the pressure before the turbine are not obvious. Therefore, in order to count the measured values of the intake air volume and the pressure before the turbine during the engine load change process to accurately judge the correlation, as a possible implementation, when the absolute value of the engine speed change rate is greater than a first limit value, or the absolute value of the engine fuel injection rate change rate is greater than a second limit value, or the absolute value of the engine intake air volume is greater than a third limit value, it is determined that the engine is operating in a preset condition; where the preset condition includes the transient transition condition during acceleration and the transient transition condition during deceleration. The values of the first limit value, the second limit value, and the third limit value are determined according to the engine performance, and the values of the first limit value, the second limit value, and the third limit value can be the same or different. Exceeding the preset limit value indicates that the engine has a normal transient response dynamically. When the engine is in the transient condition transition during acceleration or deceleration, the diagnostic condition is enabled, and the changes in the intake air volume and the measured value are relatively obvious, which can provide a reliable data basis for subsequent correlation calculation.

[0030] In addition, before performing the correlation calculation, it is also necessary to ensure that there is no electrical connection fault in the pressure sensor before the turbine to avoid misdiagnosis caused by line problems. The electrical diagnosis of the pressure sensor before the turbine is usually carried out in real time. Ensuring no electrical connection faults can improve the accuracy and reliability of the measured values collected, thereby improving the accuracy of the fault diagnosis of the pressure sensor before the turbine.

[0031] As a possible implementation, if icing occurs in the intake pipe during the operation of the whole vehicle in a low-temperature environment, it is still necessary to monitor the fault of the pressure sensor before the turbine to ensure the engine performance. Figure 2 It is a schematic diagram of the diagnostic enabling logic for the fault diagnosis of the pressure sensor before the turbine provided by an exemplary embodiment of the present application, and can be set as Figure 2The diagnostic enabling logic shown, that is, the engine speed is within a preset speed range, the engine fuel injection volume is within a preset fuel injection volume range, the ambient temperature is less than a preset temperature threshold, and there are no related faults in the turbine inlet pressure sensor, etc. On this basis, when the absolute value of the engine speed change rate is greater than a first limit value, or the absolute value of the engine fuel injection volume change rate is greater than a second limit value, or the absolute value of the engine intake air volume is greater than a third limit value, if any one of these three conditions is met, subsequent correlation calculations and fault judgments can be carried out. It can be understood that in addition to the above setting condition methods, the preconditions can also be adjusted according to actual needs to improve the flexibility of turbine inlet pressure sensor faults.

[0032] Continue to refer to Figure 1 , in S102, based on the engine intake air volume and the measured value of the turbine inlet pressure sensor, calculate the correlation.

[0033] Among them, the correlation characterizes the correlation between the change degree of the turbine inlet pressure and the change degree of the intake air volume. Under steady-state conditions, an increase in the turbine inlet pressure means an increase in the pressure in the intake manifold, which will cause more air to be sucked into the cylinder, thereby increasing the intake air volume. At this time, the change in the turbine inlet pressure and the change in the intake air volume usually show a positive correlation. However, in transient conditions such as sudden acceleration and sudden deceleration, the situation becomes complicated. Due to factors such as the response delay of the turbocharger, the volume effect of the intake manifold, and the response speed of the sensor itself, the change in the turbine inlet pressure may not be able to reflect the actual change in the intake air volume in a timely and accurate manner. Under normal circumstances, although the engine intake air volume and the turbine inlet pressure (the measured value of the turbine inlet pressure sensor) are not synchronized, the change trends should still maintain a certain dynamic coupling (such as the phase difference can be controlled). That is to say, the change degree of the turbine inlet pressure transient and the change degree of the intake air volume can calculate the correlation, so as to judge the high or low correlation between the change degree of the turbine inlet pressure transient and the change degree of the intake air volume, that is, to judge whether the measured value of the turbine inlet pressure sensor changes with the change of the engine intake air volume.

[0034] In some embodiments, when the engine operating condition meets the preset conditions, record the engine intake air volume once every preset step length as the first data to obtain the first array; when the engine operating condition meets the preset conditions, record the measured value of the turbine inlet pressure sensor once every preset step length as the second data to obtain the second array; among them, the measured value includes the first array and the second array. That is to say, when the engine is in the transient condition transition of acceleration or deceleration, the diagnostic condition is enabled. At this time, record an engine intake air volume in a first array S for each step length x , record a measured value of the turbine inlet pressure sensor in the second array S y for subsequent correlation calculations.

[0035] Generally, the amount of data recorded during one acceleration or deceleration (the measured value of the pre-vortex pressure sensor and the intake air volume of the engine) is relatively small. After the engine runs stably, it returns to the enable condition judgment. When the condition is met again (the operating condition of the engine meets the preset condition), relevant data is continuously recorded until the recorded data meets the calculation requirements (the amount of recorded data can be calibrated in the engine's ECU based on the data in the normal state and the icing state). Therefore, in some embodiments, to ensure the accuracy and reliability of subsequent calculations, when the data volume of the first array and the data volume of the second array are both greater than the preset data volume, the correlation is calculated based on the first array and the second array.

[0036] There are multiple values in the first array and the second array. When calculating the correlation between the two arrays (or variables), it can be quantified through covariance. Covariance is the core statistic because it directly quantifies the common change trend of the first array and the second array, that is, the common change trend of the intake air volume of the engine and the pre-vortex pressure. In some embodiments, the standard deviation of the first array is calculated; the standard deviation of the second array is calculated; when the standard deviation of the first array is greater than or equal to the first preset value and the standard deviation of the second array is greater than or equal to the second preset value, the covariance of the first array and the second array is calculated; wherein, the covariance characterizes the direction and degree of the common change of the intake air volume of the engine and the measured value of the pre-vortex pressure sensor. Covariance is the basis for calculating correlation. The sign of the covariance determines the positive or negative of the correlation. The larger the absolute value of the covariance, the stronger the original intensity of the common change of the variables. Covariance is the mathematical basis of correlation analysis. The correlation coefficient is derived from covariance and standard deviation. Therefore, covariance provides the original intensity of the relationship between variables, and after standardization (correlation), it is comparable and interpretable. The main purpose of calculating the sample standard deviation before calculating the covariance is data standardization and validity check to ensure the reliability of subsequent analysis.

[0037] As a possible implementation, the standard deviation of the first array can be calculated using Formula 1:

[0038]

[0039] where S x represents the standard deviation of the first array, X i represents the i-th observation value in the first array (the intake air volume of the engine for a certain measurement), represents the mean of the first array, n represents the sample size (the number of intake air volumes of the engine), represents the deviation of each intake air volume of the engine from the mean (reflecting the deviation degree of a single data).

[0040] The standard deviation of the second array can be calculated using Formula 2:

[0041]

[0042] Among them, S y represents the standard deviation of the second array, and Y i represents the i-th observation value in the second array (the measured value of the pre-vortex pressure sensor in a certain measurement), represents the mean of the second array, and n represents the sample size (the number of measured values of the pre-vortex pressure sensor), represents the deviation of the intake air volume of the measured value of each pre-vortex pressure sensor from the mean (reflecting the degree of deviation of a single data).

[0043] The covariance of the first array and the second array can be calculated using Equation 3:

[0044]

[0045] Among them, S xy represents the covariance of the first array and the second array, represents the mean of the first array, represents the mean of the second array, and X i and Y i represent the i-th pair of observation values of two variables (the intake air volume of the engine and the measured value of the pre-vortex pressure sensor), represents the deviation of the intake air volume of each engine from the mean, represents the deviation of the intake air volume of the measured value of each pre-vortex pressure sensor from the mean.

[0046] If S xy is greater than 0, it can be shown that the intake air volume of the engine and the pre-vortex pressure tend to be higher or lower than the mean at the same time (positive correlation). If S xy is less than 0, it can be shown that the intake air volume of the engine and the pre-vortex pressure tend to change in the opposite direction (negative correlation). If S xy is equal to 0, it indicates that there is no linear relationship between the intake air volume of the engine and the pre-vortex pressure. Therefore, the larger the absolute value of the covariance, the stronger the co-variation of the two variables. However, its value is affected by the units of the variables.

[0047] Covariance is affected by the dimension of the variables and cannot directly compare the association strength of different data sets. That is to say, the absolute value of the covariance reflects the original strength of the co-variation of the variables, but the dimension influence needs to be eliminated by standardizing with the standard deviation to obtain a comparable correlation coefficient. Therefore, in order to eliminate the dimension influence and be more comparable, in some embodiments, according to the standard deviation of the first array, the standard deviation of the second array, and the covariance, the correlation is calculated; among them, the correlation is positively correlated with the covariance and negatively correlated with the product of the standard deviation of the first array and the standard deviation of the second array. That is to say, the covariance is standardized, and the standardization formula can use Equation 4:

[0048]

[0049] where S xy represents the covariance of the first array and the second array, and S x represents the standard deviation of the first array, and S y represents the standard deviation of the second array, and r xy represents the standardized covariance. The value range of r xy is [-1, 1], dimensionless (not affected by units). Therefore, by comparing r xy with a preset threshold, it can be determined whether the measured value of the pre-vortex pressure sensor changes with the engine intake air volume, so as to determine whether the pre-vortex pressure sensor is faulty.

[0050] In S103, when the correlation is less than or equal to the preset threshold, it is determined that the pre-vortex pressure sensor is faulty.

[0051] In some embodiments, after calculating r xy , since r xy is dimensionless, it can be directly compared with the preset threshold. For example, if the calculation result of r xy is greater than the preset threshold (such as 0.8), it is considered that the degree of change of the pre-vortex pressure transient is highly correlated with the degree of change of the intake air volume, and the sensor transient normal measurement is fault-free. If it is less than the preset threshold (such as 0.8), it is considered that the degree of change of the pre-vortex pressure transient is lowly correlated with the degree of change of the intake air volume, and the sensor may be frozen. Multiple judgments can be made according to this method to finally determine whether it is blocked due to icing.

[0052] In some embodiments, when it is determined that the pre-vortex pressure sensor is faulty, a control instruction is issued; wherein, the control instruction is used to instruct the exhaust throttle valve to perform open-loop control or open the exhaust throttle valve. For example, after it is determined that the intake pipe is frozen, the exhaust throttle valve can be controlled in open loop or the exhaust throttle valve can be opened in the fault state to avoid further blockage caused by faults during post-treatment. And continue to perform diagnosis in real time. If the icing melts after the engine load increases and the sensor can continue to measure, it can return to the process of closed-loop control of the exhaust throttle valve based on the pre-vortex pressure.

[0053] Regarding the problem that it is difficult to diagnose the fault of the pre-vortex pressure sensor in a vehicle during operation, a vehicle is proposed below, including: a pre-vortex pressure sensor and an exhaust manifold; wherein, the exhaust manifold is connected to the pre-vortex pressure sensor through a pressure-taking pipe; like the pre-vortex pressure sensor fault diagnosis device provided in the present application, the pre-vortex pressure sensor fault diagnosis device is used to diagnose the fault of the pre-vortex pressure sensor.

[0054] Wherein, Figure 3It is a schematic flowchart of a diagnostic method for a fault diagnosis device of a pre-turbine pressure sensor provided by an exemplary embodiment of the present application. One diagnostic method of the pre-turbine pressure sensor fault diagnosis device can be as follows: First, it is judged whether a preset condition is met (see Figure 3 S301), if the preset condition is not met, the enable diagnosis is continued and the correlation is not calculated temporarily. If the preset condition is met, the intake air volume of the engine is recorded as the first data every preset step length to obtain the first array (see Figure 3 S302), the measured value of the pre-turbine pressure sensor is recorded as the second data every preset step length to obtain the second array (see Figure 3 S303), and then it is judged whether the data of the preset data volume is accumulated enough (see Figure 3 S304). If the quantities are all greater than or equal to the preset data volume, the correlation is calculated (see Figure 3 S305). If the quantities are all less than the preset data volume, the first data and the second data in the transient state are continuously collected and recorded in the corresponding arrays. It is judged whether the correlation is greater than the preset threshold (see Figure 3 S306). If the correlation is less than or equal to the preset threshold, it is determined that the pre-turbine pressure sensor fails (see Figure 3 S307). If the correlation is greater than the preset threshold, it is determined that the pre-turbine pressure sensor has no fault (see Figure 3 S308). Therefore, the pre-turbine pressure sensor fault diagnosis device can improve the real-time monitoring of the pre-turbine pressure sensor and the accuracy of fault judgment, thereby reducing the possibility of the problem that the exhaust throttle valve cannot be controlled due to the failure not being judged, and improving the performance and operation safety of the vehicle engine.

[0055] Figure 4 It is a schematic structural diagram of a pre-turbine pressure sensor fault diagnosis device provided by an exemplary embodiment of the present application. The pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine. As Figure 4 shown, the pre-turbine pressure sensor fault diagnosis device 4 includes: an acquisition module 41, configured to acquire the intake air volume of the engine and the measured value of the pre-turbine pressure sensor when the operating condition of the engine meets the preset condition; a calculation module 42, configured to calculate the correlation based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, where the correlation characterizes the correlation between the change degree of the pre-turbine pressure and the change degree of the intake air volume; a determination module 43, configured to determine that the pre-turbine pressure sensor fails when the correlation is less than or equal to the preset threshold.

[0056] The fault diagnosis device for the pre-turbine pressure sensor provided by this application can determine whether the pre-turbine pressure sensor is faulty when the engine is in operation, that is, it diagnoses by making a correlation judgment between the pre-turbine pressure measured by the pre-turbine pressure sensor and the engine intake air volume. Through the correlation between the engine intake air volume and the measured value of the pre-turbine pressure sensor, it can accurately diagnose whether the pre-turbine pressure sensor has an icing fault during engine operation, improving the real-time monitoring of the pre-turbine pressure sensor and the accuracy of fault judgment, thereby reducing the possibility of problems such as the exhaust throttle valve being uncontrollable due to the inability to determine the fault, and improving the engine performance and operation safety.

[0057] As a possible implementation, the acquisition module 41 can be configured as follows: when the operating condition of the engine meets the preset conditions, record the engine intake air volume as the first data every preset step length to obtain the first array; when the operating condition of the engine meets the preset conditions, record the measured value of the pre-turbine pressure sensor as the second data every preset step length to obtain the second array; where the measured value includes the first array and the second array.

[0058] As a possible implementation, the calculation module 42 can be configured as follows: when the data volumes of both the first array and the second array are greater than the preset data volume, calculate the correlation based on the first array and the second array.

[0059] As a possible implementation, the calculation module 42 can also be configured as follows: calculate the standard deviation of the first array; calculate the standard deviation of the second array; when the standard deviation of the first array is greater than or equal to the first preset value and the standard deviation of the second array is greater than or equal to the second preset value, calculate the covariance of the first array and the second array; where the covariance characterizes the direction and degree of the common change between the engine intake air volume and the measured value of the pre-turbine pressure sensor.

[0060] As a possible implementation, the calculation module 42 can also be configured as follows: calculate the correlation according to the standard deviation of the first array, the standard deviation of the second array, and the covariance; where the correlation is positively correlated with the covariance and negatively correlated with the product of the standard deviation of the first array and the standard deviation of the second array.

[0061] As a possible implementation, the fault diagnosis device 4 for the pre-turbine pressure sensor can also be configured as follows: when it is determined that the pre-turbine pressure sensor is faulty, issue a control instruction; where the control instruction is used to instruct the exhaust throttle valve to perform open-loop control or open the exhaust throttle valve.

[0062] As a possible implementation, the acquisition module 41 can be configured to: when the engine speed is within a preset speed range, the engine fuel injection rate is within a preset fuel injection amount range, and the ambient temperature at which the engine operates is lower than a preset temperature threshold, determine whether the engine is operating in a preset working condition according to the engine operation change rate; when the engine is operating in the preset working condition, acquire the intake air volume of the engine and the measurement value of the pressure sensor in front of the turbine.

[0063] As a possible implementation, the acquisition module 41 can also be configured to: when the absolute value of the engine speed change rate is greater than a first limit value, or the absolute value of the engine fuel injection amount change rate is greater than a second limit value, or the absolute value of the engine intake air volume is greater than a third limit value, determine that the engine is operating in a preset working condition; wherein, the preset working condition includes an acceleration transient transition condition and a deceleration transient transition condition.

[0064] The method in this application can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in this application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, a core network device, an OAM, or other programmable devices.

[0065] The computer program product can be written in any combination of one or more programming languages to write program code for performing the operations of the embodiments of this application. The programming languages include object-oriented programming languages, such as Java, C++, etc., and also include conventional procedural programming languages, such as the "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, executed as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0066] The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center integrating one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile types of storage media.

[0067] In addition, an embodiment of the present application can also be a storage medium on which a computer program is stored, and the computer program is executed by a processor to perform the steps in a method for diagnosing a fault of a vortex front pressure sensor described in any of the above embodiments of this specification:

[0068] For the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0069] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments.

[0070] The steps in the methods of the embodiments of the present application can be adjusted, combined, and deleted according to actual needs. The technical features recorded in each embodiment can be replaced or combined. The devices in the embodiments of the present application can be combined, divided, and deleted according to actual needs.

[0071] Those skilled in the art may further realize that the units and algorithm steps of each example described in connection with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0072] The steps of the methods or algorithms described in connection with the embodiments disclosed herein can be directly implemented by hardware, software units executed by a processor, or a combination of the two. The software units can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0073] Finally, it should also be noted that in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0074] The above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for diagnosing faults of a pre-vortex pressure sensor, characterized in that, The pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine; Among them, the fault diagnosis method of the pre-turbine pressure sensor includes: When the operating condition of the engine meets the preset conditions, obtain the intake air volume of the engine and the measured value of the pre-turbine pressure sensor; Based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, calculate the correlation; wherein, the correlation characterizes the correlation between the change degree of the pre-turbine pressure and the change degree of the intake air volume; When the correlation is less than or equal to the preset threshold, determine that the pre-turbine pressure sensor fails.

2. The fault diagnosis method of the pre-vortex pressure sensor according to claim 1, wherein, When the operating condition of the engine meets the preset conditions, obtaining the intake air volume of the engine and the measured value of the pre-turbine pressure sensor includes: When the operating condition of the engine meets the preset conditions, record the intake air volume of the engine as the first data every preset step length, and obtain the first array; When the operating condition of the engine meets the preset conditions, record the measured value of the pre-turbine pressure sensor as the second data every preset step length, and obtain the second array; Among them, the measured value includes the first array and the second array.

3. The method for diagnosing the fault of the pressure sensor in front of the turbine according to claim 2, characterized in that, Based on the intake air volume of the engine and the measured value of the pre-turbine pressure sensor, calculating the correlation includes: When the data amounts of the first array and the second array are both greater than the preset data amount, calculate the correlation based on the first array and the second array.

4. The method for diagnosing the failure of the pressure sensor in front of the turbine according to claim 3, wherein, Calculating the correlation based on the first array and the second array includes: Calculate the standard deviation of the first array; Calculate the standard deviation of the second array; When the standard deviation of the first array is greater than or equal to the first preset value, and the standard deviation of the second array is greater than or equal to the second preset value, calculate the covariance of the first array and the second array; wherein, the covariance characterizes the common change direction and degree of the intake air volume of the engine and the measured value of the pre-turbine pressure sensor.

5. The method for diagnosing the failure of the pre-vortex pressure sensor according to claim 4, wherein Calculating the correlation based on the first array and the second array further includes: According to the standard deviation of the first array, the standard deviation of the second array and the covariance, calculate the correlation; wherein, the correlation is positively correlated with the covariance, and the correlation is negatively correlated with the product of the standard deviation of the first array and the standard deviation of the second array.

6. The method for diagnosing the fault of the pre-vortex pressure sensor according to claim 1, wherein, The fault diagnosis method of the pre-turbine pressure sensor further includes: When it is determined that the pre-turbine pressure sensor fails, send a control instruction; wherein, the control instruction is used to instruct the exhaust throttle valve to perform open-loop control or open the exhaust throttle valve.

7. The fault diagnosis method of the pre-vortex pressure sensor according to claim 1, characterized in that, When the operating condition of the engine meets the preset conditions, obtaining the intake air volume of the engine and the measured value of the pre-turbine pressure sensor includes: When the engine speed is within the preset speed range, the engine fuel injection rate is within the preset fuel injection amount range, and the ambient temperature of the engine operation is lower than the preset temperature threshold, determine whether the engine is operating in the preset working condition according to the engine operation change rate; When the engine is operating in the preset working condition, obtain the intake air volume of the engine and the measured value of the pre-turbine pressure sensor.

8. The method for diagnosing the fault of the pre-vortex pressure sensor according to claim 7, characterized in that, Determining whether the engine is operating in the preset working condition according to the engine operation change rate includes: When the absolute value of the engine speed change rate is greater than a first limit value, or the absolute value of the engine fuel injection quantity change rate is greater than a second limit value, or the absolute value of the engine intake air quantity is greater than a third limit value, it is determined that the engine operates in a preset condition; wherein, the preset condition includes an acceleration transient transition condition and a deceleration transient transition condition.

9. A fault diagnosis device for a vortex front pressure sensor, characterized in that, The pre-turbine pressure sensor is used to measure the pressure of the exhaust manifold in front of the turbine of the engine; Among them, the pre-turbine pressure sensor fault diagnosis device includes: An acquisition module, configured to acquire the intake air quantity of the engine and the measured value of the pre-turbine pressure sensor when the operating condition of the engine meets a preset condition; A calculation module, configured to calculate a correlation based on the intake air quantity of the engine and the measured value of the pre-turbine pressure sensor; wherein, the correlation characterizes the correlation between the change degree of the pre-turbine pressure and the change degree of the intake air quantity; A determination module, configured to determine that the pre-turbine pressure sensor fails when the correlation is less than or equal to a preset threshold.

10. A vehicle, characterized in that, Includes: A pre-turbine pressure sensor and an exhaust manifold; wherein, the exhaust manifold is connected to the pre-turbine pressure sensor through a pressure-taking pipe; The pre-turbine pressure sensor fault diagnosis device according to claim 9 above, and the pre-turbine pressure sensor fault diagnosis device is used to diagnose faults of the pre-turbine pressure sensor.

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