Method for diagnosing failure of engine air system, diagnosis device, and diagnosis system

Abstract

The application provides a method, device and system for diagnosing faults of an engine air system. The method comprises: a first obtaining step of obtaining a first data set and a second data set, the first data set comprising a plurality of intake flow rates of the engine; a calculating step of calculating a plurality of intake residuals from the first data set, calculating a plurality of recovery residuals from the second data set, and constructing a residual set from the plurality of intake residuals and recovery residuals; a querying step of querying a first mapping relationship according to each element in the set and a target fault type to obtain a target preset condition; a first determining step of determining that a fault corresponding to the target fault type exists in the case that each element meets a sub-condition of the corresponding target preset condition; and repeating the querying step and the determining step until whether faults corresponding to all fault types of the air system exist are determined. The method solves the problem of inaccurate fault diagnosis caused by the small application range of the air system fault diagnosis method in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data communication, in particular to an engine air system fault diagnosis method, a diagnosis device, a computer readable storage medium and a diagnosis system. BACKGROUND

[0002] The air system fault detection method in the prior art: detection method 1: only through the comparison of the MAP sensor and the model of the MAP sensor. Deviation out of limit reports fault. Detection method 2: directly compare the values between MAP and PTP sensors, and report fault if the value is out of limit. The air system fault diagnosis is not systematic at present. For the credibility, two modes are often compared. For diagnosis method 1: for the existing model-based diagnosis method, if the MAP sensor is normal, and the sensors involved in the model for calculating MAP appear deviation, the calculated MAP and the model appear deviation, and only the fault of the MAP sensor can still be reported. For diagnosis method 2: this recognition mode can only correctly report when the fault deviation is large, and can only diagnose the deviation in one direction. Therefore, the existing diagnosis system has the defects of narrow diagnosis allowable working condition range, only diagnosing large deviation fault, large false report probability, unclear fault recognition and the like. SUMMARY

[0003] The main purpose of the present application is to provide an engine air system fault diagnosis method, a diagnosis device, a computer readable storage medium and a diagnosis system, so as to at least solve the problem that the air system fault diagnosis method in the prior art has small applicable range, resulting in inaccurate fault diagnosis.

[0004] In order to achieve the above object, according to one aspect of the present application, a method for diagnosing faults of an engine air system is provided, comprising: a first obtaining step of obtaining a first data set and a second data set, the first data set comprising a plurality of intake flow rates of an engine, the plurality of intake flow rates being obtained by different first calculation methods, the first calculation methods comprising a Venturi flow calculation formula, a throttle equation and a speed density method, the second data set comprising a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates being obtained by different second calculation methods, the second calculation methods comprising a throttle equation of an EGR valve and a flow balance equation; a calculation step of calculating a plurality of intake residuals according to the first data set, calculating a plurality of recovery residuals according to the second data set, and constructing a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set being the intake residual or the recovery residual, the intake residual being a difference between any two of the intake flow rates, and the recovery residual being a difference between any two of the recovery flow rates; a query step of querying a first mapping relationship according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship being a mapping relationship among the elements, the fault type and a preset condition, the preset condition corresponding to the fault type one by one, the preset condition comprising a plurality of sub-conditions, the sub-condition corresponding to the element one by one, the target fault type being one of fault types of the engine air system, and the target preset condition being the preset condition corresponding to the target fault type; a first determination step of determining that a fault corresponding to the target fault type exists when each of the elements satisfies the sub-condition of the target preset condition corresponding thereto; and repeating the query step and the determination step at least once in turn until whether faults corresponding to all of the fault types of the air system exist are determined.

[0005] Optionally, the first data group comprises a first intake flow rate, a second intake flow rate and a third intake flow rate, and the second data group comprises a first recovery flow rate, a second recovery flow rate, a third recovery flow rate and a fourth recovery flow rate, and the obtaining of the first data group and the second data group comprises: obtaining a first pressure, a second pressure, a third pressure, a fourth pressure, a first opening degree and a second opening degree, wherein the first pressure is a pressure on an intake side of a throttle valve, the second pressure is a pressure at a throat of an EGR mixer, the third pressure is a pressure of an intake manifold, the fourth pressure is a pressure on an intake side of an EGR valve, the first opening degree is an opening degree of the throttle valve, and the second opening degree is an opening degree of the EGR valve; substituting the first pressure and the second pressure into a Venturi flow calculation formula to calculate an air flow rate, thereby obtaining the first intake flow rate; substituting the first pressure, the third pressure and the first opening degree into a throttle equation of the throttle valve to calculate the air flow rate, thereby obtaining the second intake flow rate; calculating the air flow rate according to the third pressure and the fourth pressure by using a velocity-density method, thereby obtaining the third intake flow rate; substituting the second pressure, the fourth pressure and the second opening degree into the throttle equation of the EGR valve to calculate an exhaust flow rate, thereby obtaining the first recovery flow rate; substituting the third pressure, the fourth pressure and the second opening degree into the throttle equation of the EGR valve to calculate the exhaust flow rate, thereby obtaining the second recovery flow rate; substituting the third pressure and the first intake flow rate into a flow balance equation, thereby obtaining the third recovery flow rate; substituting the third pressure and the second intake flow rate into the flow balance equation, thereby obtaining the fourth recovery flow rate; and constructing the first data group according to the first intake flow rate, the second intake flow rate and the third intake flow rate, and constructing the second data group according to the first recovery flow rate, the second recovery flow rate, the third recovery flow rate and the fourth recovery flow rate.

[0006] Optionally, the calculating of the plurality of intake residuals according to the first data group comprises: calculating a difference between the first intake flow rate and the second intake flow rate to obtain a first intake residual; calculating a difference between the second intake flow rate and the third intake flow rate to obtain a second intake residual; and calculating a difference between the first intake flow rate and the third intake flow rate to obtain a third intake residual.

[0007] Optionally, the plurality of recovery residuals are calculated according to the second data set, including: calculating a first recovery residual by subtracting the second recovery flow from the first recovery flow; calculating a second recovery residual by subtracting the third recovery flow from the first recovery flow; calculating a third recovery residual by subtracting the fourth recovery flow from the first recovery flow; calculating a fourth recovery residual by subtracting the third recovery flow from the second recovery flow; calculating a fifth recovery residual by subtracting the fourth recovery flow from the second recovery flow; and calculating a sixth recovery residual by subtracting the fourth recovery flow from the third recovery flow.

[0008] Optionally, in the case that each of the elements satisfies the corresponding sub-condition of the target preset condition, it is determined that the fault corresponding to the target fault type exists, including: a second obtaining step of obtaining any one of the elements and the corresponding sub-condition; a second determining step of determining that the element satisfies the corresponding sub-condition in the case that the sub-condition corresponding to the element is a first sub-condition and the first sub-condition is satisfied, determining that the element satisfies the corresponding sub-condition in the case that the sub-condition corresponding to the element is a second sub-condition and the second sub-condition is satisfied, determining that the element satisfies the corresponding sub-condition in the case that the sub-condition corresponding to the element is a third sub-condition and the third sub-condition is satisfied, and determining that the element satisfies the sub-condition in the case that the sub-condition corresponding to the element is a fourth sub-condition and the fourth sub-condition is satisfied, the first sub-condition being that the element is greater than 0 and an over-limit state corresponding to the element is over upper limit, the second sub-condition being that the element is less than 0 and the over-limit state corresponding to the element is over lower limit, the third sub-condition being that the over-limit state corresponding to the element is not over limit, and the fourth sub-condition being that the over-limit state corresponding to the element is one of the over upper limit, the over lower limit, and the not over limit, the over upper limit being used to represent that the element is greater than an upper limit value of a corresponding preset range, the over lower limit being used to represent that the element is less than a lower limit value of the corresponding preset range, and the not over limit being used to represent that the element is within the corresponding preset range; the second obtaining step and the second determining step are repeated in sequence at least once until it is determined whether all elements satisfy the sub-condition; and in the case that the sub-conditions corresponding to all elements are satisfied, it is determined that the fault corresponding to the target fault type exists, and in the case that any one of the sub-conditions corresponding to the elements is not satisfied, it is determined that the fault corresponding to the target fault type does not exist.

[0009] Optionally, before determining that the fault corresponding to the target fault type exists, when each of the elements meets the sub-condition of the corresponding target preset condition, the method further comprises: a third acquisition step of acquiring any one of the elements, and querying a second mapping relationship according to the element to obtain a target preset range, the second mapping relationship being a mapping relationship between the element and a preset range, the element and the preset range being in one-to-one correspondence; a third determination step of determining that the element is in the over-upper limit when the element is greater than an upper limit value of the target preset range, determining that the element is in the over-lower limit when the element is less than a lower limit value of the target preset range, and determining that the element is in the non-over-limit when the element is within the target preset range; and sequentially repeating the third acquisition step and the third determination step at least once until the over-limit states of all the elements are determined.

[0010] Optionally, before acquiring the first data group and the second data group, the method further comprises: adjusting the first opening degree until the first opening degree is less than a first preset value, and adjusting the second opening degree until the second opening degree is greater than a second preset value.

[0011] According to another aspect of the present application, there is provided a device for diagnosing faults of an engine air system, the device comprising: a first obtaining unit configured to obtain, in a first obtaining step, a first data set and a second data set, the first data set comprising a plurality of intake flow rates of an engine, the plurality of intake flow rates being obtained by different first calculation manners, the first calculation manners comprising a Venturi flow calculation formula, a throttle equation and a speed density method, the second data set comprising a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates being obtained by different second calculation manners, the second calculation manners comprising a throttle equation of an EGR valve and a flow balance equation; a calculation unit configured to calculate a plurality of intake residuals according to the first data set, calculate a plurality of recovery residuals according to the second data set, and construct a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set being the intake residual or the recovery residual, the intake residual being a difference between any two of the intake flow rates, the recovery residual being a difference between any two of the recovery flow rates; a querying unit configured to query, in a querying step, a first mapping relationship according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship being a mapping relationship among the elements, the fault type and a preset condition, the preset condition corresponding to the fault type one by one, the preset condition comprising a plurality of sub-conditions, the sub-condition corresponding to the element one by one, the target fault type being one of fault types of an air system of the engine, the target preset condition being the preset condition corresponding to the target fault type; a first determining unit configured to determine, in a first determining step, that a fault corresponding to the target fault type exists in a case where each of the elements satisfies the sub-condition of the target preset condition corresponding to the element; and a first repeating unit configured to repeat the querying step and the determining step at least once in turn until whether faults corresponding to all of the fault types of the air system exist are determined.

[0012] According to still another aspect of the present application, there is provided a computer-readable storage medium comprising a stored program, wherein the program, when executed, controls a device in which the computer-readable storage medium is located to perform any of the methods.

[0013] According to yet another aspect of the present application, there is provided a diagnostic system comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise instructions for performing any of the methods.

[0014] Applying the technical solution of this application, in the above-mentioned engine air system fault diagnosis method, firstly, in the first acquisition step, a first data set and a second data set are acquired. The first data set includes multiple intake air flow rates of the engine, which are obtained through different first calculation methods, including the Venturi flow rate calculation formula, the throttle equation of the throttle valve, and the velocity density method. The second data set includes multiple exhaust gas recovery flow rates of the engine, which are obtained through different second calculation methods, including the throttle equation of the EGR valve and the flow balance equation. Then, in the calculation step, multiple intake residuals are calculated based on the first data set, multiple recovery residuals are calculated based on the second data set, and a residual set is constructed based on the multiple intake residuals and the multiple recovery residuals. The elements in the residual set are either the intake residuals or the recovery residuals, and the intake residuals are any two upper... The difference in intake airflow is given, and the recovery residual is the difference between any two of the recovered airflow rates. Then, in the query step, a first mapping relationship is queried based on each of the elements and the target fault type to obtain the target preset condition. The first mapping relationship is a mapping relationship between the elements, the fault type, and the preset condition. The preset condition corresponds one-to-one with the fault type, and includes multiple sub-conditions, each corresponding one-to-one with the element. The target fault type is one of the fault types of the engine's air system, and the target preset condition is the preset condition corresponding to the target fault type. Next, in the first determination step, if each element satisfies the corresponding sub-condition of the target preset condition, it is determined that the fault corresponding to the target fault type exists. Finally, the query step and the determination step are repeated at least once until it is determined whether the faults corresponding to all the fault types of the air system exist. This application acquires pressure and opening data from different locations in the engine's air system, calculates multiple intake airflow and exhaust gas recovery flow rates using various calculation methods, and then calculates multiple residuals by subtracting each pair of intake airflow rates and exhaust gas recovery flow rates. It then determines whether these residuals meet preset judgment conditions to identify the existence of a fault corresponding to a specific fault type, thus providing a comprehensive assessment of the air system. Compared to existing technologies that only compare intake manifold pressure with a model or compare intake manifold and throttle pressure, which can only monitor faults at fixed locations, this application, based on residual status, can diagnose faults at various locations. This application solves the problem of limited applicability and inaccurate fault diagnosis in existing air system fault diagnosis methods. Attached Figure Description

[0015] Figure 1 A hardware structure block diagram of a mobile terminal for diagnosing engine air system faults provided in an embodiment of this application is shown.

[0016] Figure 2 A flowchart of a method for diagnosing engine air system faults is shown according to an embodiment of the present application;

[0017] Figure 3 An algorithm flowchart of a method for diagnosing engine air system faults is shown according to an embodiment of the present application;

[0018] Figure 4 An algorithm flowchart of a method for diagnosing engine air system faults is shown according to an embodiment of the present application;

[0019] Figure 5 A flowchart of a method for diagnosing engine air system faults is shown according to an embodiment of the present application;

[0020] Figure 6 A structural block diagram of a method for diagnosing engine air system faults is shown according to an embodiment of the present application.

[0021] Among the above figures, the following reference signs are included:

[0022] 102, processor; 104, memory; 106, transmission device; 108, input / output device. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments and features in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below 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. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should belong to the scope of protection of the present application.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0026] For ease of description, the following describes some nouns or terms related to the embodiments of the present application:

[0027] EGR mixer: EGR (Exhaust Gas Recirculation), i.e. the exhaust gas recirculation technology, which is a technology that divides part of the exhaust gas and introduces it into the suction side to make it re-suction in small internal combustion engines for automobiles, and the EGR mixer is a device for realizing this technology.

[0028] EGR valve: a device installed on the engine for controlling the circulation amount of exhaust gas recirculation.

[0029] As introduced in the background, in the prior art, the deviation is reported according to the comparison between the intake manifold pressure sensor and the corresponding model, or the fault is judged according to the deviation value between the intake manifold pressure and the pressure of the throttle valve, and the allowable working condition range is narrow, and only the fault with too large deviation can be diagnosed. To solve the problem that the air system fault diagnosis method in the prior art has a small applicable range, leading to inaccurate fault diagnosis, the embodiments of the present application provide a diagnosis method, a diagnosis device, a computer readable storage medium and a diagnosis system for engine air system faults.

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application.

[0031] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking the running on a mobile terminal as an example, Figure 1 is a hardware structure block diagram of a mobile terminal of an engine air system fault diagnosis method according to an embodiment of the present application. As Figure 1 shown, the mobile terminal can include one or more Figure 1The mobile terminal can further include a transmission device 106 for communication function and an input / output device 108. Those skilled in the art can understand that, Figure 1 The structure shown is only schematic and does not limit the structure of the mobile terminal. For example, the mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown. Figure 1 The mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown. Figure 1 The mobile terminal can include more or less components than those shown, or have a different configuration of components than those shown.

[0032] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as a computer program corresponding to the method for displaying device information in the embodiments of the present application. The processor 102 can execute various functional applications and data processing by running the computer programs stored in the memory 104, i.e., implement the method described above. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include a memory remotely arranged with respect to the processor 102, and the remote memory can be connected to the mobile terminal through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific examples of the network can include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0033] In the embodiments, a method for diagnosing an engine air system fault is provided, which is run on a mobile terminal, a computer terminal or a similar computing device. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0034] Figure 2 is a flowchart of the method for diagnosing an engine air system fault according to the embodiments of the present application. As Figure 2 shown, the method includes the following steps:

[0035] Step S201, a first obtaining step, obtaining a first data set and a second data set, the first data set comprising a plurality of intake flow rates of an engine, the plurality of intake flow rates being obtained by different first calculation manners, the first calculation manners comprising a Venturi flow calculation formula, a throttle equation and a velocity density method, the second data set comprising a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates being obtained by different second calculation manners, the second calculation manners comprising a throttle equation of an EGR valve and a flow balance equation;

[0036] Specifically, a plurality of pressures and valve openings are monitored by sensors installed at different parts of the intake system, and then a plurality of intake flow rates and a plurality of recovery flow rates are obtained according to different calculation manners, i.e., the first data set and the second data set are obtained.

[0037] Step S202, calculating a plurality of intake residuals according to the first data set, calculating a plurality of recovery residuals according to the second data set, and constructing a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set being the intake residual or the recovery residual, the intake residual being a difference between any two of the intake flow rates, and the recovery residual being a difference between any two of the recovery flow rates;

[0038] Specifically, a plurality of intake residuals corresponding to the first data set are obtained by taking differences between the intake flow rates two by two, a plurality of recovery residuals corresponding to the second data set are obtained by taking differences between the recovery flow rates two by two, and then the residual set is obtained by constructing a set according to the intake residuals and the recovery residuals.

[0039] Step S203, a querying step, querying a first mapping relationship according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship being a mapping relationship among the elements, the fault type and the preset condition, the preset condition corresponding to the fault type one by one, the preset condition comprising a plurality of sub-conditions, the sub-conditions corresponding to the elements one by one, the target fault type being one of fault types of an air system of the engine, and the target preset condition being the preset condition corresponding to the target fault type;

[0040] Specifically, the mapping relationship is stored in the ECU in the form of a table, as shown in Table 1, the fault types comprising PTP being higher than a trusted range, Pnozz being higher than a trusted range, MAP being higher than a trusted range and EGRP being higher than a trusted range, wherein PTP is a throttle pressure, Pnozz is a pressure at a throat of a Venturi EGR mixer, MAP is an intake manifold pressure, and P EGR EGRP is a pressure of an EGR valve. r1 to r9 are a plurality of the residuals, and 1, 0, -1 and 2 are identifiers of the preset conditions.

[0041] Table 1

[0042]

[0043] Step S204, a first determining step, in the case that each of the above elements meets the corresponding above target preset condition, it is determined that the fault corresponding to the target fault type exists;

[0044] Specifically, according to whether the residual value of each residual meets the preset condition in Table 1, it can be determined whether the fault of the corresponding fault type exists.

[0045] In a specific implementation, in the case that each residual meets the preset condition, it is determined that the fault exists, and in the case that any one of the above residuals does not meet the preset condition, it is determined that the fault does not exist.

[0046] Step S205, the above query step and the above determining step are repeated at least once in turn until it is determined whether the fault corresponding to all the fault types of the air system exists.

[0047] Specifically, the above query step and the above determining step are repeated to traverse all the preset fault types, to determine whether the residual meets the preset condition, and further to determine the fault in the air system.

[0048] Through the embodiment, first, a first acquisition step, a first data set and a second data set are acquired, the first data set includes a plurality of intake flow rates of an engine, the plurality of intake flow rates are obtained by different first calculation methods, the first calculation methods include a Venturi flow calculation formula, a throttle equation of a throttle valve and a speed density method, the second data set includes a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates are obtained by different second calculation methods, the second calculation methods include a throttle equation of an EGR valve and a flow balance equation; then, a calculation step, a plurality of intake residual errors are calculated according to the first data set, a plurality of recovery residual errors are calculated according to the second data set, and a residual error set is constructed according to the plurality of intake residual errors and the plurality of recovery residual errors, elements in the residual error set are the intake residual errors or the recovery residual errors, the intake residual error is a difference value of any two of the intake flow rates, and the recovery residual error is a difference value of any two of the recovery flow rates; thereafter, a query step, a first mapping relationship is queried according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship is a mapping relationship of the elements, the fault type and the preset condition, the preset condition corresponds to the fault type in a one-to-one manner, the preset condition includes a plurality of sub-conditions, the sub-conditions correspond to the elements in a one-to-one manner, the target fault type is one of fault types of an air system of the engine, and the target preset condition is the preset condition corresponding to the target fault type; thereafter, a first determination step, in a case where each of the elements meets the sub-condition of the target preset condition, it is determined that a fault corresponding to the target fault type exists; and finally, the query step and the determination step are repeated at least once in sequence until it is determined whether faults corresponding to all of the fault types of the air system exist. The application obtains pressure data and opening degree data at different positions of an engine air system, obtains a plurality of intake flow rates and exhaust gas recovery flow rates by different calculation methods, then obtains a plurality of residual errors by pairwise difference of the intake flow rates, obtains a plurality of residual errors by pairwise difference of the recovery flow rates, determines whether the residual errors meet a preset determination condition, determines whether a fault corresponding to a fault type exists, and comprehensively judges the air system. Compared with the prior art which only compares the intake manifold pressure with a model or compares the intake manifold pressure and the throttle valve pressure, only the faults at fixed positions can be monitored, and the application can diagnose faults at various positions according to the residual error state. The application solves the problem of small application range of the air system fault diagnosis method in the prior art, which leads to inaccurate fault diagnosis.

[0049] In order to obtain the first data set and the second data set, the first data set includes a first intake flow rate, a second intake flow rate and a third intake flow rate, and the second data set includes a first recovery flow rate, a second recovery flow rate, a third recovery flow rate and a fourth recovery flow rate. In an optional embodiment, the step S201 includes:

[0050] In step S2011, the first pressure, the second pressure, the third pressure, the fourth pressure, the first opening degree and the second opening degree are acquired. The first pressure is the pressure on the intake side of the throttle valve, the second pressure is the pressure at the throat of the EGR mixer, the third pressure is the pressure of the intake manifold, the fourth pressure is the pressure on the intake side of the EGR valve, the first opening degree is the opening degree of the throttle valve, and the second opening degree is the opening degree of the EGR valve.

[0051] Specifically, the pressure on the intake side of the intake valve, the pressure at the throat of the Venturi mixer, the pressure of the intake manifold, the pressure on the intake side of the EGR valve, the opening degree of the throttle valve and the opening degree of the EGR valve are acquired by the throttle valve front pressure sensor, the Venturi mixer throat pressure sensor, the intake manifold pressure sensor, the EGR valve front pressure sensor, the throttle valve and the EGR valve installed in the intake system.

[0052] In step S2012, the first intake flow rate is calculated by substituting the first pressure and the second pressure into the Venturi flow calculation formula.

[0053] Specifically, as shown in Table 2, PTP and Pnozz are substituted into the formula , that is, the first intake flow rate is obtained, wherein k1 is a calibration coefficient.

[0054] Table 2

[0055]

[0056] In step S2013, the second intake flow rate is calculated by substituting the first pressure, the third pressure and the first opening degree into the throttle equation of the throttle valve.

[0057] Specifically, as shown in Table 2, PTP, MAP and WDKVP (throttle opening degree) are substituted into the formula, and the second intake flow rate is obtained by calculation, wherein the formula is , wherein k2 is a calibration coefficient.

[0058] In step S2014, the third intake flow rate is calculated by the speed density method according to the third pressure and the fourth pressure.

[0059] Specifically, as shown in Table 2, P EGR and MAP are substituted into the formula m VE =k3(MAP-PEDR)N, that is, the third intake flow rate is obtained, wherein k3 is a calibration coefficient, and N is the engine speed.

[0060] Step S2015, the above-mentioned second pressure, the above-mentioned fourth pressure and the above-mentioned second opening degree are substituted into the above-mentioned throttling equation of the above-mentioned EGR valve to calculate the exhaust gas flow to obtain the above-mentioned first recovery flow;

[0061] Specifically, P EGR , Pnozz, EGRVP (EGR valve opening degree) are substituted into the formula , that is, the above-mentioned first recovery flow is obtained, wherein k4 is a calibration coefficient.

[0062] Step S2016, the above-mentioned third pressure, the above-mentioned fourth pressure and the above-mentioned second opening degree are substituted into the above-mentioned throttling equation of the above-mentioned EGR valve to calculate the above-mentioned exhaust gas flow to obtain the above-mentioned second recovery flow;

[0063] Specifically, P EGR , Pnozz, EGRVP are substituted into the formula , that is, the above-mentioned second recovery flow is obtained, wherein k5 is a calibration coefficient.

[0064] Step S2017, the above-mentioned third pressure and the above-mentioned first intake flow are substituted into the above-mentioned flow balance equation to obtain the above-mentioned third recovery flow;

[0065] Specifically, MAP and m noz are substituted into the formula m EGR3 =k6MAP*N-m noz , that is, the above-mentioned third recovery flow is obtained, wherein k6 is a calibration coefficient.

[0066] Step S2018, the above-mentioned third pressure and the above-mentioned second intake flow are substituted into the above-mentioned flow balance equation to obtain the above-mentioned fourth recovery flow;

[0067] Specifically, MAP and m DVE2 are substituted into the formula m EGR4 =k6MAP*N-m DVE2 , that is, the above-mentioned fourth recovery flow is obtained, wherein k7 is a calibration coefficient.

[0068] Step S2019, the above-mentioned first data group is constructed according to the above-mentioned first intake flow, the above-mentioned second intake flow and the above-mentioned third intake flow, and the above-mentioned second data group is constructed according to the above-mentioned first recovery flow, the above-mentioned second recovery flow, the above-mentioned third recovery flow and the above-mentioned fourth recovery flow.

[0069] Specifically, the data groups are respectively constructed according to the plurality of intake flows and the plurality of recovery flows, that is, the above-mentioned first data group and the above-mentioned second data group are obtained.

[0070] To obtain each of the above intake residual errors, in an alternative embodiment, the step S202 includes:

[0071] Step S2021, calculating the difference between the first intake flow rate and the second intake flow rate to obtain a first intake residual error;

[0072] Specifically, as shown in Table 1, the difference between m noz -m DVE2 is calculated, i.e. the first intake residual error is obtained.

[0073] Step S2022, calculating the difference between the second intake flow rate and the third intake flow rate to obtain a second intake residual error;

[0074] Specifically, as shown in Table 1, the difference between m noz -m VE is calculated, i.e. the second intake residual error is obtained.

[0075] Step S2023, calculating the difference between the first intake flow rate and the third intake flow rate to obtain a third intake residual error.

[0076] Specifically, as shown in Table 1, the difference between m DVE2 -m VE is calculated, i.e. the third intake residual error is obtained.

[0077] To obtain each of the above recovery residual errors, in an alternative embodiment, the step S202 further includes:

[0078] Step S2024, calculating the difference between the first recovery flow rate and the second recovery flow rate to obtain a first recovery residual error;

[0079] Specifically, as shown in Table 1, the difference between m EGR1 -m EGR2 is calculated, i.e. the first recovery residual error is obtained.

[0080] Step S2025, calculating the difference between the first recovery flow rate and the third recovery flow rate to obtain a second recovery residual error;

[0081] Specifically, as shown in Table 1, the difference between m EGR1 -m EGR3 is calculated, i.e. the second recovery residual error is obtained.

[0082] Step S2026, calculating the difference between the first recovery flow rate and the fourth recovery flow rate to obtain a third recovery residual error;

[0083] Specifically, as shown in Table 1, the difference between m EGR1 -m EGR4 is calculated, i.e. the third recovery residual error is obtained.

[0084] Step S2027: Calculate the difference between the second and third recovery flows to obtain the fourth recovery residual;

[0085] Specifically, as shown in Table 1, calculate m EGR2 -m EGR3 The difference is the fourth recovery residual mentioned above.

[0086] Step S2028: Calculate the difference between the second and fourth recovery flows to obtain the fifth recovery residual;

[0087] Specifically, as shown in Table 1, calculate m EGR2 -m EGR4 The difference is the fifth recovery residual mentioned above.

[0088] Step S2029: Calculate the difference between the third and fourth recovery flows to obtain the sixth recovery residual.

[0089] Specifically, as shown in Table 1, calculate m EGR3 -m EGR4 The difference is the sixth recovery residual mentioned above.

[0090] In order to determine the preset conditions corresponding to the above-mentioned fault types based on whether each residual satisfies the corresponding sub-condition, in an optional implementation, the above-mentioned step S204 includes:

[0091] Step S2041, the second acquisition step, acquire any one of the above elements and the corresponding above sub-conditions;

[0092] Specifically, such as Figure 3 As shown, obtain any residual r i And whether the corresponding sub-condition judgment residual satisfies the corresponding sub-condition.

[0093] Step S2042, the second determining step: If the sub-condition corresponding to the element is the first sub-condition and satisfies the first sub-condition, then the element is determined to satisfy the corresponding sub-condition. If the sub-condition corresponding to the element is the second sub-condition and satisfies the second sub-condition, then the element is determined to satisfy the corresponding sub-condition. If the sub-condition corresponding to the element is the third sub-condition and satisfies the third sub-condition, then the element is determined to satisfy the corresponding sub-condition. If the sub-condition corresponding to the element is the fourth sub-condition and satisfies the fourth sub-condition, then the element is determined to satisfy the sub-condition. The first sub-condition is that the element is greater than 0 and the over-limit state corresponding to the element is above the upper limit; the second sub-condition is that the element is less than 0 and the over-limit state corresponding to the element is below the lower limit; the third sub-condition is that the over-limit state corresponding to the element is not above the limit; the fourth sub-condition is that the over-limit state corresponding to the element is one of the above upper limit, the above lower limit, and the above not above the limit. The above upper limit is used to indicate that the element is greater than the upper limit of the corresponding preset range; the above lower limit is used to indicate that the element is less than the lower limit of the corresponding preset range; and the above not above the limit is used to indicate that the element is within the corresponding preset range.

[0094] In specific implementation, when making sub-condition decisions, as shown in Table 1, if the fault type is PTP higher than the confidence range and the corresponding residual is the first residual mentioned above, its condition parameter is 1. That is, when the first residual is greater than 0 and the corresponding over-limit state is above the upper limit, the first residual is determined to satisfy the corresponding sub-condition. When the corresponding residual is the fourth residual mentioned above, its condition parameter is 2. That is, regardless of which over-limit state the fourth residual belongs to, the fourth residual is determined to satisfy the corresponding sub-condition. If the fault type is Pnozz higher than the confidence range, when the corresponding residual is the first residual, its condition parameter is -1. That is, when the first residual is less than 0 and the corresponding over-limit state is below the lower limit, the first residual is determined to satisfy the corresponding sub-condition. When the corresponding residual is the third residual mentioned above, its condition parameter is 0. That is, when the over-limit state corresponding to the third residual is not above the limit, the third residual is determined to satisfy the corresponding sub-condition.

[0095] Step S2043: Repeat the above second acquisition step and the above second determination step at least once, until it is determined whether all elements satisfy the above sub-conditions;

[0096] Specifically, such as Figure 3 As shown, after completing a residual r i Following the judgment, the fault type T is judged sequentially. j Do the other residuals satisfy the corresponding sub-conditions?

[0097] Step S2044, in the case that each of the above-mentioned sub-conditions is satisfied, it is determined that the fault corresponding to the target fault type exists, and in the case that any one of the above-mentioned sub-conditions is not satisfied, it is determined that the fault corresponding to the target fault type does not exist.

[0098] Specifically, as shown in the figure, Figure 3 after the determination of whether the residual of this type satisfies the corresponding sub-condition is completed, in the case that all the sub-conditions are satisfied, it is determined that the fault of this type exists, otherwise it is determined that the corresponding fault does not exist.

[0099] In order to obtain the over-limit state of all residuals, in an optional embodiment, before it is determined that the fault corresponding to the target fault type exists in the case that each of the above-mentioned elements satisfies the corresponding target preset condition, the method further comprises:

[0100] Step S301, a third obtaining step, obtaining any one of the above-mentioned elements, and obtaining a target preset range according to the element by querying a second mapping relationship, the second mapping relationship being a mapping relationship between the element and the preset range, and the element and the preset range corresponding to each other;

[0101] Specifically, as shown in the figure, Figure 4 any one of the residuals and the preset range corresponding to the residual in the ECU is obtained, that is, the element and the target preset range are obtained.

[0102] Step S302, a third determining step, in the case that the element is greater than the upper limit value of the target preset range, it is determined that the over-limit state of the element is over-upper limit, in the case that the element is less than the lower limit value of the target preset range, it is determined that the over-limit state of the element is over-lower limit, and in the case that the element is within the target preset range, it is determined that the over-limit state corresponding to the element is not over-limited.

[0103] Specifically, as shown in the figure, Figure 4 in the case that the residual exceeds the upper limit value of the preset range, it is determined that the over-limit state of the residual is over-upper limit, in the case that the residual exceeds the lower limit value of the preset range, it is determined that the over-limit state of the residual is over-lower limit, and in the case that the residual is within the preset range, it is determined that the over-limit state of the residual is not over-limited.

[0104] Step S303, the second obtaining step and the second determining step are repeated at least once in turn until the over-limit state corresponding to all the elements is determined.

[0105] Specifically, the above-mentioned process is repeated, and the over-limit state of all residuals is determined according to each residual and the corresponding preset range.

[0106] In order to ensure the accuracy of the above fault decision, in an alternative embodiment, before obtaining the first data set and the second data set, the method further comprises:

[0107] Step S401, adjust the first opening degree until the first opening degree is less than the first preset value, and adjust the second opening degree until the second opening degree is greater than the second preset value.

[0108] Specifically, the residual data is best within a certain working condition range, so before making a fault decision, first adjust the engine operating condition to the enabled range, that is, adjust the first opening degree until the first opening degree is less than the first preset value, and adjust the second opening degree until the second opening degree is greater than the second preset value.

[0109] In a specific implementation, the actual running state of the engine is determined, and after determining that there is a fault, the engine state is adjusted to the enabled working condition for a determination.

[0110] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the implementation process of the engine air system fault diagnosis method of the present application will be described in detail below with specific examples.

[0111] The present embodiment relates to a specific engine air system fault diagnosis method, as shown in Figure 5 The method comprises the following steps:

[0112] Step S1: Obtain the throttle inlet side pressure PTP, the pressure Pnozz at the throat of the Venturi mixer, the intake manifold pressure MAP, the intake side pressure P EGR of the EGR valve, the throttle opening degree WDKVP and the EGR valve opening degree EGRVP through sensors;

[0113] Step S2: Calculate three intake flow rates using the Venturi mixer flow calculation formula, the throttle restriction equation and the speed density method respectively according to the above data, and obtain three residuals by pairwise subtracting the intake flow rates;

[0114] Step S3: Calculate four recovery flow rates according to the EGR valve restriction equation and the flow balance equation respectively according to the above data, and obtain six residuals by pairwise subtracting the recovery flow rates;

[0115] Step S4: Compare the nine residuals with the corresponding confidence ranges one by one to determine the over-limit state of the nine residuals, that is, when the residual exceeds the upper limit of the confidence range, determine the over-limit state as over-limit upper, recorded as 1, when the residual exceeds the lower limit of the confidence range, determine the over-limit state as over-limit lower, recorded as -1, and when the residual is within the confidence range, determine the over-limit state as not over-limit, recorded as 0, to obtain a residual over-limit state table;

[0116] Step S5: Then, according to the residual over-limit state table and the fault state decision condition preset table, the fault state of the air system is determined. When the corresponding preset condition parameter is 1, the over-limit state of the corresponding residual is required to be 1 and the residual value is greater than 0; when the corresponding preset condition parameter is -1, the over-limit state of the corresponding residual is required to be -1 and the residual value is less than 0; when the corresponding preset condition parameter is 0, the over-limit state of the corresponding residual is required to be 0; and when the corresponding preset condition parameter is 2, the over-limit state of the corresponding residual is not limited.

[0117] In addition, the fault state decision condition preset table is shown in Table 1.

[0118] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that here.

[0119] The application also provides an engine air system fault diagnosis method device. It should be noted that the engine air system fault diagnosis method device of the application can be used to execute the engine air system fault diagnosis method provided by the application. The device is used to realize the above-mentioned embodiments and preferred embodiments, which have been described. As used below, the term "module" can be a combination of software and / or hardware that realizes a predetermined function. Although the device described in the following embodiments is preferably realized in software, hardware or a combination of software and hardware is also possible and is conceived.

[0120] The engine air system fault diagnosis method device provided by the application is described below.

[0121] Figure 6 is a structure block diagram of the engine air system fault diagnosis method device according to the application. As shown in Figure 6 , the device includes:

[0122] The first acquisition unit 10 is used for the first acquisition step, and acquires a first data set and a second data set. The first data set includes a plurality of intake flow rates of an engine, and the plurality of intake flow rates are obtained by different first calculation methods, including a Venturi flow calculation formula, a throttle equation of a throttle valve and a speed density method. The second data set includes a plurality of recovery flow rates of exhaust gas of the engine, and the plurality of recovery flow rates are obtained by different second calculation methods, including a throttle equation of an EGR valve and a flow balance equation.

[0123] Specifically, a plurality of pressures and valve openings are monitored by sensors installed at different positions of the intake system, and then a plurality of intake flow rates and a plurality of recovery flow rates are obtained according to different calculation methods, i.e. the first data set and the second data set are obtained.

[0124] The calculation unit 20 is configured to calculate a plurality of intake residuals according to the first data set, calculate a plurality of recovery residuals according to the second data set, and construct a residual set according to the plurality of intake residuals and the plurality of recovery residuals, wherein each element in the residual set is the intake residual or the recovery residual, the intake residual is the difference between any two intake flow rates, and the recovery residual is the difference between any two recovery flow rates.

[0125] Specifically, the plurality of intake residuals corresponding to the first data set are obtained by taking the difference between any two intake flow rates, the recovery residuals corresponding to the second data set are obtained by taking the difference between any two recovery flow rates, and then the residual set is constructed according to the intake residuals and the recovery residuals.

[0126] The query unit 30 is configured to query the first mapping relationship according to each element and a target fault type to obtain a target preset condition, wherein the first mapping relationship is a mapping relationship among the element, the fault type and the preset condition, the preset condition corresponds to the fault type one by one, the preset condition includes a plurality of sub-conditions, the sub-condition corresponds to the element one by one, the target fault type is one of the fault types of the air system of the engine, and the target preset condition is the preset condition corresponding to the target fault type.

[0127] Specifically, the mapping relationship is stored in the ECU in the form of a table, as shown in Table 1, and the fault types include PTP higher than the trusted range, Pnozz higher than the trusted range, MAP higher than the trusted range and EGRP higher than the trusted range, wherein PTP is the throttle pressure, Pnozz is the pressure at the throat of the Venturi EGR mixer, MAP is the intake manifold pressure, and EGRP is the pressure of the EGR valve. EGR r1 to r9 are the plurality of residuals, and 1, 0, -1 and 2 are the identifiers of the preset conditions.

[0128] The first determination unit is configured to determine that the fault corresponding to the target fault type exists in the first determination step when each element satisfies the corresponding target preset condition.

[0129] Specifically, whether the fault corresponding to the fault type exists can be determined according to whether the residual value of each residual satisfies the preset condition in Table 1.

[0130] In specific implementations, the fault is determined to exist when each of the residuals satisfies the preset condition, and the fault is determined to not exist when any one of the residuals does not satisfy the preset condition.

[0131] The first repeating unit is configured to sequentially repeat the query step and the determination step at least once until it is determined whether the faults of all the fault types of the air system exist.

[0132] Specifically, the query step and the determination step are repeated to traverse all the preset fault types, determine whether the residuals satisfy the preset condition, and further determine the faults in the air system.

[0133] By the embodiment, the first obtaining unit is configured to obtain the first data set and the second data set in the first obtaining step, the first data set comprises a plurality of intake flow rates of an engine, the plurality of intake flow rates are obtained by different first calculation manners, the first calculation manners comprise a Venturi flow calculation formula, a throttle equation and a speed density method, and the second data set comprises a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates are obtained by different second calculation manners, the second calculation manners comprise a throttle equation of an EGR valve and a flow balance equation; the calculation unit is configured to calculate a plurality of intake residuals according to the first data set, calculate a plurality of recovery residuals according to the second data set, and construct a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set is the intake residual or the recovery residual, the intake residual is a difference between any two of the intake flow rates, and the recovery residual is a difference between any two of the recovery flow rates; the query unit is configured to query a first mapping relationship according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship is a mapping relationship among the elements, the fault type and the preset condition, the preset condition corresponds to the fault type in a one-to-one manner, the preset condition comprises a plurality of sub-conditions, the sub-conditions correspond to the elements in a one-to-one manner, the target fault type is one of fault types of an air system of the engine, and the target preset condition is the preset condition corresponding to the target fault type; the first determination unit is configured to determine that a fault corresponding to the target fault type exists in a case where each of the elements satisfies the sub-condition of the target preset condition; and the first repeating unit is configured to sequentially repeat the query step and the determination step at least once until it is determined whether faults corresponding to all of the fault types of the air system exist. The application obtains pressure data and opening degree data at different positions of an engine air system, obtains a plurality of intake flow rates and exhaust gas recovery flow rates by different calculation manners, further obtains a plurality of residuals by making a difference between two of the intake flow rates, obtains a plurality of residuals by making a difference between two of the recovery flow rates, determines whether the residuals satisfy a preset determination condition, determines whether a fault corresponding to a fault type exists, and comprehensively judges the air system. Compared with the prior art which only compares intake manifold pressure with a model or compares intake manifold pressure and throttle pressure, only fixed position faults can be monitored, and the application can diagnose faults at various positions according to residual states. The application solves the problem of small application range of the air system fault diagnosis mode in the prior art, which leads to inaccurate fault diagnosis.

[0134] In order to obtain the first data set and the second data set, the first data set comprises a first intake flow, a second intake flow and a third intake flow, and the second data set comprises a first recovery flow, a second recovery flow, a third recovery flow and a fourth recovery flow, in an alternative embodiment, the first obtaining unit comprises:

[0135] The first obtaining module is configured to obtain a first pressure, a second pressure, a third pressure, a fourth pressure, a first opening degree and a second opening degree, the first pressure is a pressure on an intake side of a throttle valve, the second pressure is a pressure at a throat of an EGR mixer, the third pressure is a pressure of an intake manifold, the fourth pressure is a pressure on an intake side of an EGR valve, the first opening degree is an opening degree of the throttle valve, and the second opening degree is an opening degree of the EGR valve.

[0136] Specifically, the first pressure, the second pressure, the third pressure and the fourth pressure are obtained by a pressure sensor installed before the throttle valve, a pressure sensor at the throat of the Venturi mixer, a pressure sensor of the intake manifold, a pressure sensor before the EGR valve, the throttle valve and the EGR valve, respectively.

[0137] The first calculating module is configured to calculate the air flow by substituting the first pressure and the second pressure into the Venturi flow calculation formula, so as to obtain the first intake flow.

[0138] Specifically, as shown in Table 2, PTP and Pnozz are substituted into the formula , so as to obtain the first intake flow, wherein k1 is a calibration coefficient.

[0139] The second calculating module is configured to calculate the air flow by substituting the first pressure, the third pressure and the first opening degree into the throttle equation of the throttle valve, so as to obtain the second intake flow.

[0140] Specifically, as shown in Table 2, PTP, MAP and WDKVP (the opening degree of the throttle valve) are substituted into the formula, and the operation is performed, so as to obtain the second intake flow, and the formula is , wherein k2 is a calibration coefficient.

[0141] The third calculating module is configured to calculate the air flow by the speed density method according to the third pressure and the fourth pressure, so as to obtain the third intake flow.

[0142] Specifically, as shown in Table 2, PEGR and MAP are substituted into the formula m VE =k3 (MAP-PEDR) N, so as to obtain the third intake flow, wherein k3 is a calibration coefficient, and N is the engine speed.

[0143] a fourth calculation module configured to calculate the exhaust gas flow by substituting the second pressure, the fourth pressure and the second opening degree into the throttle equation of the EGR valve to obtain the first recovery flow;

[0144] Specifically, as shown in Table 2, substituting PEGR, Pnozz, EGRVP (EGR valve opening degree) into the formula , i.e. obtaining the first recovery flow, wherein k4 is a calibration coefficient.

[0145] a fifth calculation module configured to calculate the exhaust gas flow by substituting the third pressure, the fourth pressure and the second opening degree into the throttle equation of the EGR valve to obtain the second recovery flow;

[0146] Specifically, as shown in Table 2, substituting PEGR, Pnozz, EGRVP into the formula , i.e. obtaining the second recovery flow, wherein k5 is a calibration coefficient.

[0147] a sixth calculation module configured to calculate the third recovery flow by substituting the third pressure and the first intake flow into the flow balance equation;

[0148] Specifically, as shown in Table 2, substituting MAP and m noz into the formula m EGR3 =k6MAP*N-m noz , i.e. obtaining the third recovery flow, wherein k6 is a calibration coefficient.

[0149] a seventh calculation module configured to calculate the fourth recovery flow by substituting the third pressure and the second intake flow into the flow balance equation;

[0150] Specifically, as shown in Table 2, substituting MAP and m DVE2 into the formula m EGR4 =k6MAP*N-m DVE2 , i.e. obtaining the fourth recovery flow, wherein k7 is a calibration coefficient.

[0151] a construction module configured to construct the first data group according to the first intake flow, the second intake flow and the third intake flow, and to construct the second data group according to the first recovery flow, the second recovery flow, the third recovery flow and the fourth recovery flow.

[0152] Specifically, the data groups are respectively constructed according to the plurality of intake flows and the plurality of recovery flows, i.e. obtaining the first data group and the second data group.

[0153] In order to obtain each intake residual error, in an optional embodiment, the calculation unit comprises:

[0154] The eighth calculation module is configured to calculate a difference between the first intake flow rate and the second intake flow rate to obtain a first intake residual error.

[0155] Specifically, as shown in Table 1, a difference between m noz and m DVE2 is calculated, i.e., the first intake residual error is obtained.

[0156] The ninth calculation module is configured to calculate a difference between the second intake flow rate and the third intake flow rate to obtain a second intake residual error.

[0157] Specifically, as shown in Table 1, a difference between m noz and m VE is calculated, i.e., the second intake residual error is obtained.

[0158] The tenth calculation module is configured to calculate a difference between the first intake flow rate and the third intake flow rate to obtain a third intake residual error.

[0159] Specifically, as shown in Table 1, a difference between m DVE2 and m VE is calculated, i.e., the third intake residual error is obtained.

[0160] In order to obtain the above-mentioned recovery residual errors, in an optional embodiment, the calculation unit further comprises:

[0161] The eleventh calculation module is configured to calculate a difference between the first recovery flow rate and the second recovery flow rate to obtain a first recovery residual error.

[0162] Specifically, as shown in Table 1, a difference between m EGR1 and m EGR2 is calculated, i.e., the first recovery residual error is obtained.

[0163] The twelfth calculation module is configured to calculate a difference between the first recovery flow rate and the third recovery flow rate to obtain a second recovery residual error.

[0164] Specifically, as shown in Table 1, a difference between m EGR1 and m EGR3 is calculated, i.e., the second recovery residual error is obtained.

[0165] The thirteenth calculation module is configured to calculate a difference between the first recovery flow rate and the fourth recovery flow rate to obtain a third recovery residual error.

[0166] Specifically, as shown in Table 1, a difference between m EGR1 and m EGR4 is calculated, i.e., the third recovery residual error is obtained.

[0167] The fourteenth calculation module is used to calculate the difference between the second and third recovery flows to obtain the fourth recovery residual.

[0168] Specifically, as shown in Table 1, calculate m EGR2 -m EGR3 The difference is the fourth recovery residual mentioned above.

[0169] The fifteenth calculation module is used to calculate the difference between the second and fourth recovery flows to obtain the fifth recovery residual.

[0170] Specifically, as shown in Table 1, calculate m EGR2 -m EGR4 The difference is the fifth recovery residual mentioned above.

[0171] The sixteenth calculation module is used to calculate the difference between the third and fourth recovery flows to obtain the sixth recovery residual.

[0172] Specifically, as shown in Table 1, calculate m EGR3 -m EGR4 The difference is the sixth recovery residual mentioned above.

[0173] In order to determine the preset conditions corresponding to the above-mentioned fault type based on whether each residual satisfies the corresponding sub-condition, in an optional implementation, the first determining unit includes:

[0174] The second acquisition module is used in the second acquisition step to acquire any one of the above elements and the corresponding above sub-conditions;

[0175] Specifically, such as Figure 3 As shown, obtain any residual r i And whether the corresponding sub-condition judgment residual satisfies the corresponding sub-condition.

[0176] A first determining module is used in the second determining step to determine that, if the sub-condition corresponding to the element is a first sub-condition and is satisfied, the element satisfies the corresponding sub-condition; if the sub-condition corresponding to the element is a second sub-condition and is satisfied, the element satisfies the corresponding sub-condition; if the sub-condition corresponding to the element is a third sub-condition and is satisfied, the element satisfies the corresponding sub-condition; and if the sub-condition corresponding to the element is a fourth sub-condition and is satisfied, the element satisfies the corresponding sub-condition. The first sub-condition is that the element is greater than 0 and the over-limit state corresponding to the element is above the upper limit; the second sub-condition is that the element is less than 0 and the over-limit state corresponding to the element is below the lower limit; the third sub-condition is that the over-limit state corresponding to the element is not above the limit; the fourth sub-condition is that the over-limit state corresponding to the element is one of the above upper limit, the above lower limit, and the above not above the limit. The above upper limit is used to indicate that the element is greater than the upper limit of the corresponding preset range; the above lower limit is used to indicate that the element is less than the lower limit of the corresponding preset range; and the above not above the limit is used to indicate that the element is within the corresponding preset range.

[0177] In specific implementation, when making sub-condition decisions, as shown in Table 1, if the fault type is PTP higher than the confidence range and the corresponding residual is the first residual mentioned above, its condition parameter is 1. That is, when the first residual is greater than 0 and the corresponding over-limit state is above the upper limit, the first residual is determined to satisfy the corresponding sub-condition. When the corresponding residual is the fourth residual mentioned above, its condition parameter is 2. That is, regardless of which over-limit state the fourth residual belongs to, the fourth residual is determined to satisfy the corresponding sub-condition. If the fault type is Pnozz higher than the confidence range, when the corresponding residual is the first residual, its condition parameter is -1. That is, when the first residual is less than 0 and the corresponding over-limit state is below the lower limit, the first residual is determined to satisfy the corresponding sub-condition. When the corresponding residual is the third residual mentioned above, its condition parameter is 0. That is, when the over-limit state corresponding to the third residual is not above the limit, the third residual is determined to satisfy the corresponding sub-condition.

[0178] The repeating module is used to repeat the second acquisition step and the second determination step at least once in sequence until it is determined whether all elements satisfy the above sub-conditions.

[0179] Specifically, such as Figure 3 As shown, after completing a residual r i Following the judgment, the fault type T is judged sequentially. j Do the other residuals satisfy the corresponding sub-conditions?

[0180] The second determining module is configured to determine that the fault corresponding to the target fault type exists when all the sub-conditions corresponding to the elements are satisfied, and determine that the fault corresponding to the target fault type does not exist when any one of the sub-conditions corresponding to the elements is not satisfied.

[0181] Specifically, as shown in Figure 3 all the sub-conditions are satisfied, it is determined that the fault of this type exists, otherwise, it is determined that the corresponding fault does not exist.

[0182] In order to obtain the over-limit state of all the residuals, in an optional embodiment, the device further comprises:

[0183] The second obtaining unit is configured to, before determining that the fault corresponding to the target fault type exists when all the sub-conditions corresponding to the elements are satisfied, obtain, in the third obtaining step, any one of the elements, and obtain the target preset range according to the element and the second mapping relationship, the second mapping relationship being a mapping relationship between the element and the preset range, the element and the preset range being in one-to-one correspondence.

[0184] Specifically, as shown in Figure 4 , any one of the residuals and the preset range corresponding to the residual in the ECU is obtained, that is, the element and the target preset range are obtained.

[0185] The second determining unit is configured to, in the third determining step, determine that the over-limit state of the element is over-upper limit when the element is greater than the upper limit value of the target preset range, determine that the over-limit state of the element is over-lower limit when the element is less than the lower limit value of the target preset range, and determine that the over-limit state of the element corresponding to the element is not over-limit when the element is within the target preset range.

[0186] Specifically, as shown in Figure 4 , when the residual exceeds the upper limit value of the preset range, it is determined that the over-limit state of the residual is over-upper limit, when the residual exceeds the lower limit value of the preset range, it is determined that the over-limit state of the residual is over-lower limit, and when the residual is within the preset range, it is determined that the over-limit state of the residual is not over-limit.

[0187] The second repeating unit is configured to repeat the third obtaining step and the third determining step at least once in turn until the over-limit state of all the elements is determined.

[0188] Specifically, the above process is repeated to determine the over-limit state of all the residuals according to each residual and the corresponding preset range.

[0189] In order to ensure the accuracy of the above fault decision, in an optional embodiment, the device further comprises:

[0190] The adjusting unit is configured to adjust the first opening degree until the first opening degree is less than a first preset value and adjust the second opening degree until the second opening degree is greater than a second preset value before the first data set and the second data set are acquired.

[0191] Specifically, the residual data is best in a certain working condition range, and therefore, before the fault decision is made, the engine working condition is first adjusted to be in the enabled range, that is, the first opening degree is adjusted until the first opening degree is less than a first preset value, and the second opening degree is adjusted until the second opening degree is greater than a second preset value.

[0192] In a specific implementation, the engine actual running state is determined, and after the existing fault is determined, the engine state is adjusted to the enabled working condition for a determination.

[0193] The engine air system fault diagnosis device comprises a processor and a memory, the first acquisition unit, the calculation unit, the query unit, the first determination unit, the first repeating unit, and the like are stored in the memory as program units, and the corresponding functions are realized by the processor executing the program units stored in the memory. The modules are located in the same processor, or the modules are located in different processors in any combination.

[0194] The processor comprises a core, and the core calls the corresponding program units from the memory. One or more than one core can be set, and the core parameters are adjusted to determine the fault type of the engine air system.

[0195] The memory can comprise a non-permanent memory in a computer readable medium, a random access memory (RAM), and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory comprises at least one memory chip.

[0196] The embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium comprises a stored program, wherein the computer readable storage medium controls a device where the computer readable storage medium is located to execute the engine air system fault diagnosis method when the program runs.

[0197] The embodiment of the present application provides a processor, and the processor is used for running a program, wherein the engine air system fault diagnosis method is executed when the program runs.

[0198] The embodiment of the present application provides a diagnosis system, which comprises a first communication domain, a second communication domain processor, a memory, and a program stored in the memory and executable on the processor, and the processor implements the steps of the diagnosis method for engine air system fault when executing the program.

[0199] The present application also provides a computer program product suitable for executing the program of the steps of the diagnosis method for engine air system fault when executed on a data processing device.

[0200] Obviously, those skilled in the art should understand that the modules or steps of the present application described above can be realized by general computing devices, which can be centralized on a single computing device or distributed on a network composed of multiple computing devices, and can be realized by program codes executable by the computing devices, so that they can be stored in storage devices and executed by the computing devices, and in some cases, the steps shown or described can be executed in different sequences, or they can be respectively manufactured into individual integrated circuit modules, or multiple modules or steps can be manufactured into a single integrated circuit module. Thus, the present application is not limited to any specific combination of hardware and software.

[0201] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0202] The present application is described with reference to flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks can be realized by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device for realizing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The devices for realizing the functions specified in one block or multiple blocks.

[0203] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0204] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0205] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0206] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, or non-volatile random access memory (NVRAM), for the storage of information, such as data files or program

[0207] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for the storage of information. The information can be computer readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile discs (DVDs) or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0208] It should also be noted that the terms "comprising", "comprises", "including", "includes" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0209] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0210] 1) The engine air system fault diagnosis method of the application, first, the first acquisition step, acquiring a first data set and a second data set, the first data set includes a plurality of intake flow rates of the engine, a plurality of the intake flow rates are obtained by different first calculation methods, the first calculation method includes Venturi flow calculation formula, throttle equation and speed density method, the second data set includes a plurality of recovery flow rates of the exhaust gas of the engine, a plurality of the recovery flow rates are obtained by different second calculation methods, the second calculation method includes the throttle equation of the EGR valve and the flow balance equation; Then, the calculation step, according to the first data set, a plurality of intake residuals are calculated, according to the second data set, a plurality of recovery residuals are calculated, and according to a plurality of the intake residuals and a plurality of the recovery residuals, a residual set is constructed, the elements in the residual set are the intake residuals or the recovery residuals, the intake residual is the difference between any two intake flow rates, and the recovery residual is the difference between any two recovery flow rates; Then, the query step, according to each of the above elements and the target fault type, a first mapping relationship is queried to obtain a target preset condition, the above first mapping relationship is the mapping relationship of the above element, the above fault type and the preset condition, the above preset condition corresponds to the above fault type one by one, the above preset condition includes a plurality of sub-conditions, the above sub-condition corresponds to the above element one by one, the above target fault type is one of the fault types of the air system of the above engine, and the above target preset condition is the above preset condition corresponding to the above target fault type; Then, the first determination step, in the case where each of the above elements satisfies the corresponding target preset condition of the above sub-condition, it is determined that the fault corresponding to the target fault type exists; Finally, the above query step and the above determination step are repeated at least once in turn, until it is determined whether the faults corresponding to all the fault types of the air system exist. The application obtains the pressure data and the opening data of the engine air system at different positions, calculates a plurality of intake flow rates and exhaust gas recovery flow rates through different calculation methods, then calculates a plurality of residuals by making a difference between two intake flow rates, calculates a plurality of residuals by making a difference between two recovery flow rates, judges whether the residuals meet the preset judgment condition, determines whether the fault corresponding to the fault type exists, and comprehensively judges the air system. Compared with the prior art which only compares the intake manifold pressure with the model or compares the intake manifold pressure and the throttle pressure, only the faults at fixed positions can be monitored, and the application can diagnose the faults at various positions according to the residual state. The application solves the problem that the air system fault diagnosis method in the prior art has a small application range, resulting in inaccurate fault diagnosis.

[0211] 2) The engine air system fault diagnosis device of the application, the first acquisition unit is used for the first acquisition step, and first data set and second data set are acquired, the first data set includes a plurality of intake flow rates of an engine, a plurality of the intake flow rates are obtained by different first calculation methods, the first calculation method includes a Venturi flow calculation formula, a throttle equation of a throttle valve and a speed density method, the second data set includes a plurality of recovery flow rates of exhaust gas of the engine, a plurality of the recovery flow rates are obtained by different second calculation methods, the second calculation method includes a throttle equation of an EGR valve and a flow balance equation; the calculation unit is used for the calculation step, a plurality of intake residuals are calculated according to the first data set, a plurality of recovery residuals are calculated according to the second data set, and a residual set is constructed according to a plurality of the intake residuals and a plurality of the recovery residuals, elements in the residual set are the intake residuals or the recovery residuals, the intake residual is a difference value of any two intake flow rates, and the recovery residual is a difference value of any two recovery flow rates; the query unit is used for the query step, a first mapping relationship is queried according to each of the elements and a target fault type to obtain a target preset condition, the first mapping relationship is a mapping relationship of the elements, the fault type and the preset condition, the preset condition corresponds to the fault type one by one, the preset condition includes a plurality of sub-conditions, the sub-condition corresponds to the element one by one, the target fault type is one of fault types of the air system of the engine, and the target preset condition is the preset condition corresponding to the target fault type; the first determination unit is used for the first determination step, and it is determined that a fault corresponding to the target fault type exists in the case where each of the elements meets the sub-condition of the target preset condition; the first repetition unit is used for sequentially repeating the query step and the determination step at least once until it is determined whether faults corresponding to all the fault types of the air system exist. The application obtains pressure data and opening degree data at different positions of the engine air system, obtains a plurality of intake flow rates and exhaust gas recovery flow rates by different calculation methods, further obtains a plurality of residuals by making a difference between two intake flow rates, obtains a plurality of residuals by making a difference between two recovery flow rates, judges whether the residuals meet a preset judgment condition, determines whether a fault corresponding to a fault type exists, and comprehensively judges the air system. Compared with the prior art which only compares the intake manifold pressure with a model or compares the intake manifold pressure and the throttle valve pressure, only the faults at fixed positions can be monitored, and the application can diagnose faults at various positions according to the residual state. The application solves the problem that the air system fault diagnosis method in the prior art has a small application range, resulting in inaccurate fault diagnosis.

[0212] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of diagnosing a fault in an engine air system, characterized by, The method comprises: a first obtaining step of obtaining a first data set and a second data set, the first data set comprising a plurality of intake flow rates of an engine, the plurality of intake flow rates being obtained by different first calculation methods, the first calculation methods comprising a Venturi flow calculation formula, a throttle equation of a throttle valve, and a speed density method, the second data set comprising a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates being obtained by different second calculation methods, the second calculation methods comprising a throttle equation of an EGR valve and a flow balance equation; a calculation step of calculating a plurality of intake residuals according to the first data set, calculating a plurality of recovery residuals according to the second data set, and constructing a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set being the intake residual or the recovery residual, the intake residual being a difference between any two of the intake flow rates, and the recovery residual being a difference between any two of the recovery flow rates; a query step of querying a first mapping relationship according to each element and a target fault type to obtain a target preset condition, the first mapping relationship being a mapping relationship among the element, the fault type, and a preset condition, the preset condition corresponding to the fault type in a one-to-one manner, the preset condition comprising a plurality of sub-conditions, the sub-condition corresponding to the element in a one-to-one manner, the target fault type being one of fault types of an air system of the engine, and the target preset condition being the preset condition corresponding to the target fault type; a first determination step of determining that a fault corresponding to the target fault type exists in a case where each element satisfies a corresponding sub-condition of the target preset condition; the query step and the determination step are repeated at least once in sequence until it is determined whether faults corresponding to all of the fault types of the air system exist.

2. The method of claim 1, wherein, The first data set comprises a first intake flow rate, a second intake flow rate, and a third intake flow rate, the second data set comprises a first recovery flow rate, a second recovery flow rate, a third recovery flow rate, and a fourth recovery flow rate, and the first data set and the second data set are obtained by: obtaining a first pressure, a second pressure, a third pressure, a fourth pressure, a first opening degree, and a second opening degree, the first pressure being a pressure on an intake side of a throttle valve, the second pressure being a pressure at a throat of an EGR mixer, the third pressure being a pressure of an intake manifold, the fourth pressure being a pressure on an intake side of an EGR valve, the first opening degree being an opening degree of the throttle valve, and the second opening degree being an opening degree of the EGR valve; calculating the first intake flow rate by substituting the first pressure and the second pressure into the Venturi flow calculation formula to calculate an air flow rate; calculating the second intake flow rate by substituting the first pressure, the third pressure, and the first opening degree into the throttle equation of the throttle valve to calculate the air flow rate; calculating the third intake flow rate by substituting the third pressure and the fourth pressure into the speed density method to calculate the air flow rate; and substituting the second pressure, the fourth pressure and the second opening into the throttle equation of the EGR valve to calculate the exhaust flow to obtain the first recovery flow; substituting the third pressure, the fourth pressure and the second opening into the throttle equation of the EGR valve to calculate the exhaust flow to obtain the second recovery flow; substituting the third pressure and the first intake flow into the flow balance equation to obtain the third recovery flow; substituting the third pressure and the second intake flow into the flow balance equation to obtain the fourth recovery flow; constructing the first data set according to the first intake flow, the second intake flow and the third intake flow, and constructing the second data set according to the first recovery flow, the second recovery flow, the third recovery flow and the fourth recovery flow.

3. The method of claim 2, wherein, calculating a plurality of intake residuals according to the first data set, including: calculating the difference between the first intake flow and the second intake flow to obtain a first intake residual; calculating the difference between the second intake flow and the third intake flow to obtain a second intake residual; calculating the difference between the first intake flow and the third intake flow to obtain a third intake residual.

4. The method of claim 3, wherein, calculating a plurality of recovery residuals according to the second data set, including: calculating the difference between the first recovery flow and the second recovery flow to obtain a first recovery residual; calculating the difference between the first recovery flow and the third recovery flow to obtain a second recovery residual; calculating the difference between the first recovery flow and the fourth recovery flow to obtain a third recovery residual; calculating the difference between the second recovery flow and the third recovery flow to obtain a fourth recovery residual; calculating the difference between the second recovery flow and the fourth recovery flow to obtain a fifth recovery residual; calculating the difference between the third recovery flow and the fourth recovery flow to obtain a sixth recovery residual.

5. The method of claim 1, wherein, in the case that each of the elements meets the corresponding sub-condition of the target preset condition, determining that the fault corresponding to the target fault type exists, including: a second acquisition step of acquiring any one of the elements and the corresponding sub-condition; The second determining step comprises: determining that the element satisfies the corresponding sub-condition if the element corresponds to the first sub-condition and satisfies the first sub-condition, determining that the element satisfies the corresponding sub-condition if the element corresponds to the second sub-condition and satisfies the second sub-condition, determining that the element satisfies the corresponding sub-condition if the element corresponds to the third sub-condition and satisfies the third sub-condition, and determining that the element satisfies the sub-condition if the element corresponds to the fourth sub-condition and satisfies the fourth sub-condition, wherein the first sub-condition is that the element is greater than 0 and an over-limit state corresponding to the element is over upper limit, the second sub-condition is that the element is less than 0 and the over-limit state corresponding to the element is over lower limit, the third sub-condition is that the over-limit state corresponding to the element is not over limit, and the fourth sub-condition is that the over-limit state corresponding to the element is one of the over upper limit, the over lower limit, and the not over limit, the over upper limit is used to represent that the element is greater than an upper limit value of a corresponding preset range, the over lower limit is used to represent that the element is less than a lower limit value of the corresponding preset range, and the not over limit is used to represent that the element is within the corresponding preset range; The second obtaining step and the second determining step are repeated at least once in sequence until it is determined whether all elements satisfy the sub-condition; If the sub-condition corresponding to each element is satisfied, it is determined that the fault corresponding to the target fault type exists, and if any one of the sub-conditions corresponding to the elements is not satisfied, it is determined that the fault corresponding to the target fault type does not exist.

6. The method of claim 5, wherein, Before it is determined that the fault corresponding to the target fault type exists when each element satisfies the sub-condition corresponding to the target preset condition, the method further comprises: A third obtaining step of obtaining any one of the elements and querying a target preset range according to the element to obtain a second mapping relationship, wherein the second mapping relationship is a mapping relationship between the element and a preset range, and the element and the preset range are in one-to-one correspondence; A third determining step of determining that the over-limit state of the element is the over upper limit when the element is greater than an upper limit value of the target preset range, determining that the over-limit state of the element is the over lower limit when the element is less than a lower limit value of the target preset range, and determining that the over-limit state corresponding to the element is the not over limit when the element is within the target preset range; The third obtaining step and the third determining step are repeated at least once in sequence until it is determined that the over-limit state corresponding to all elements.

7. The method of claim 2, wherein, Before the first data group and the second data group are obtained, the method further comprises: The first opening degree is adjusted until the first opening degree is less than a first preset value, and the second opening degree is adjusted until the second opening degree is greater than a second preset value.

8. An apparatus for diagnosing a fault in an engine air system, characterized by The device comprises: The first obtaining unit is configured to obtain a first data set and a second data set in a first obtaining step, the first data set comprising a plurality of intake flow rates of an engine, the plurality of intake flow rates being obtained by different first calculation manners, the first calculation manners comprising a Venturi flow calculation formula, a throttle equation and a velocity-density method, and the second data set comprising a plurality of recovery flow rates of exhaust gas of the engine, the plurality of recovery flow rates being obtained by different second calculation manners, the second calculation manners comprising a throttle equation of an EGR valve and a flow balance equation; The calculating unit is configured to calculate a plurality of intake residuals according to the first data set, calculate a plurality of recovery residuals according to the second data set, and construct a residual set according to the plurality of intake residuals and the plurality of recovery residuals, an element in the residual set being the intake residual or the recovery residual, the intake residual being a difference between any two of the intake flow rates, and the recovery residual being a difference between any two of the recovery flow rates; The querying unit is configured to obtain a target preset condition by querying a first mapping relationship according to each element and a target fault type in a querying step, the first mapping relationship being a mapping relationship among the element, the fault type and a preset condition, the preset condition corresponding to the fault type in a one-to-one manner, the preset condition comprising a plurality of sub-conditions, the sub-condition corresponding to the element in a one-to-one manner, the target fault type being one of fault types of an air system of the engine, and the target preset condition being the preset condition corresponding to the target fault type; The first determining unit is configured to determine that a fault corresponding to the target fault type exists in a case where each element satisfies a corresponding sub-condition of the target preset condition in a first determining step. The first repeating unit is configured to sequentially repeat the querying step and the determining step at least once until it is determined whether faults corresponding to all of the fault types of the air system exist.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium comprises a stored program, wherein the program controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 7 when the program is executed.

10. A diagnostic system, characterized by The computer-readable storage medium comprises a stored program, wherein the program controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 7 when the program is executed. The computer-readable storage medium comprises a stored program, wherein the program controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 7 when the program is executed. The computer-readable storage medium comprises a stored program, wherein the program controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 7 when the program is executed. The computer-readable storage medium comprises a stored program, wherein the program controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 7 when the program is executed.

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