Fault diagnosis method and device for variable valve timing mechanism of engine and vehicle

Abstract

The invention provides a fault diagnosis method and device for a variable valve timing mechanism of an engine and a vehicle, and relates to the technical field of vehicle control. And respectively calculating an actual variable valve timing energy value and a target variable valve timing energy value according to the angle and a preset target variable valve timing phase angle, and then determining a fault diagnosis result of the engine variable valve timing mechanism. According to the fault diagnosis method for the variable valve timing mechanism of the engine, the diagnosis basis data is the actual variable valve timing energy value and the target variable valve timing energy value, so that compared with an existing mode of directly judging by adopting an angle value, the accuracy and the diagnosis rate of a diagnosis result can be improved; the problem that a variable valve timing mechanism cannot complete timing due to the fact that the operation condition of a hybrid vehicle type engine is fixed can be solved, and diagnosis robustness can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to a fault diagnosis method for an engine variable valve timing mechanism. At the same time, the present invention also relates to a fault diagnosis device for an engine variable valve timing mechanism for implementing the fault diagnosis method of the engine variable valve timing mechanism, and a vehicle applying the fault diagnosis device of the engine variable valve timing mechanism. Background Art

[0002] In existing hybrid vehicle models, since the engine mainly operates in the medium and high load regions, the engine needs to output a large amount of power and torque to meet the requirements of vehicle acceleration, climbing, etc. In this case, the target opening of the VVT mechanism basically remains unchanged to ensure the stability and efficiency of the engine. In the low load region, the engine load is small and does not need to output too much power. To save fuel and reduce emissions, the target angle of the VVT mechanism will move towards the reference position, that is, the valve timing is adjusted to optimize the combustion process.

[0003] Since the diagnosis process of the VVT mechanism needs to be carried out when the engine is running, however, in the actual diagnosis process, when the engine is in the low load region and the target angle moves towards the reference position, it may encounter the situation that the engine has stopped, which results in the inability to complete the fault diagnosis of the VVT mechanism, and the corresponding IUPR (In-Use Performance Ratio) numerator cannot increase, affecting the diagnosis rate of VVT diagnosis (which can be understood as the probability or ratio that the fault diagnosis method of the VVT mechanism can correctly identify and confirm the fault of the VVT mechanism under specific conditions). Summary of the Invention

[0004] In view of this, the present invention aims to propose a fault diagnosis method for an engine variable valve timing mechanism to improve the reliability of diagnosis.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A fault diagnosis method for an engine variable valve timing mechanism, the method comprising:

[0007] Obtaining the actual variable valve timing phase angle;

[0008] Calculating the actual variable valve timing energy value and the target variable valve timing energy value respectively according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle;

[0009] Determining the fault diagnosis result of the engine variable valve timing mechanism according to the actual variable valve timing energy value and the target variable valve timing energy value;

[0010] Wherein, the target variable valve timing energy value is the accumulated value of the squares of the target variable valve timing phase angle gradients within a preset time, and the actual variable valve timing energy value is the accumulated value of the squares of the actual variable valve timing phase angle gradients within the preset time.

[0011] Further, determining the fault diagnosis result of the engine variable valve timing mechanism according to the actual variable valve timing energy value and the target variable valve timing energy value includes:

[0012] Dividing the actual variable valve timing energy value by the target variable valve timing energy value to obtain the ratio of the variable valve timing phase angle change energy values;

[0013] Determining the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy values.

[0014] Further, determining the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy values includes:

[0015] Under the condition that the ratio of the variable valve timing phase angle change energy values is greater than a preset ratio threshold, preliminarily determining that the engine variable valve timing mechanism has no fault.

[0016] Further, determining the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy values further includes:

[0017] According to the determination result of preliminarily determining that the engine variable valve timing mechanism has no fault, counting the cumulative number of times that the variable valve timing mechanism has no fault within the preset time;

[0018] When the cumulative number of times reaches a preset number threshold, finally determining that the engine variable valve timing mechanism has no fault.

[0019] Further, calculating the actual variable valve timing energy value and the target variable valve timing energy value according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle respectively includes:

[0020] Under the condition that the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, calculating the target variable valve timing energy value based on the target variable valve timing phase angle, and calculating the actual variable valve timing energy value based on the actual variable valve timing phase angle.

[0021] Further, before obtaining the actual variable valve timing phase angle, the method further includes:

[0022] Obtain diagnostic enable condition information;

[0023] Determine whether the diagnostic enable condition information meets the preset requirements;

[0024] When the diagnostic enable condition information meets the preset requirements, obtain the actual variable valve timing phase angle.

[0025] Further, the diagnostic enable condition information includes at least one of the state information of the variable valve timing mechanism, the starting condition of the vehicle, and the control enable state of the variable valve timing system;

[0026] The preset requirements include that the variable valve timing mechanism has no fault, the vehicle starting condition is not in the catalyst heating condition, and the control enable state of the variable valve timing system is the preset state.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The fault diagnosis method for the engine variable valve timing mechanism of the present invention determines the fault diagnosis result of the engine variable valve timing mechanism based on the actual variable valve timing energy value and the target variable valve timing energy value. In this method, since the data for diagnosis is the actual variable valve timing energy value and the target variable valve timing energy value, compared with the existing method of directly judging using angle values, the accuracy and diagnosis rate of the diagnosis result can be improved, and the situation where the variable valve timing mechanism cannot be completed due to the fixed operating condition of the hybrid vehicle engine can be solved, which is beneficial to enhancing the diagnostic robustness (Diagnostic Robustness, which is a measure of the ability of a diagnostic system to maintain its diagnostic accuracy and reliability in the face of various uncertainties, interferences, or abnormal situations).

[0029] In addition, specifically dividing the actual variable valve timing energy value by the target variable valve timing energy value and using the obtained ratio of the variable valve timing phase angle change energy value as the calculation result, and applying this method to the fault diagnosis process is a "convenient" or "efficient" diagnostic means.

[0030] By directly calculating the ratio of the target and actual energy values, a quantitative index can be quickly obtained to evaluate the performance state of the VVT mechanism. This quantitative index is more accurate and objective than the traditional diagnosis methods based on experience or symptoms. And the calculation process is relatively simple, without the need for complex equipment or long-time data collection, enabling this diagnostic method to quickly perform fault diagnosis, which is beneficial to improving the diagnostic efficiency.

[0031] In addition, by setting a preset ratio threshold, the judgment logic for determining that the engine variable valve timing mechanism is fault-free is initially determined, which has the advantages of simplifying the diagnostic process, improving diagnostic accuracy, reducing misdiagnosis and missed diagnosis, optimizing maintenance decisions, and enhancing the user experience.

[0032] By statistically analyzing the fault-free states at multiple time points within a preset time, it is possible to more accurately evaluate whether there is a fault in the variable valve timing mechanism. Compared with the diagnostic results of a single or a few times, cumulative statistics can reduce misjudgments caused by accidental factors. Moreover, multiple fault-free records within the preset time indicate that the VVT mechanism maintains a stable operating state for a period of time, which helps technicians determine whether there are potential faults in the VVT mechanism.

[0033] Furthermore, when the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, this indicates that the engine management system or control strategy requires a large phase adjustment of the VVT mechanism. At this time, calculating the actual variable valve timing energy value and the target variable valve timing energy value based on the actual variable valve timing phase angle and the target variable valve timing phase angle respectively is a key step in evaluating the response ability and performance state of the VVT mechanism, which can more accurately evaluate the response ability and performance state of the VVT mechanism and is conducive to improving the accuracy and reliability of diagnosis.

[0034] In an engine fault diagnosis system, multiple diagnostic enabling conditions are usually set to ensure accurate diagnosis at the appropriate time and conditions. These diagnostic enabling conditions may involve multiple aspects such as the operating state of the engine and the accuracy of sensor data. When the information of these diagnostic enabling conditions simultaneously meets the requirements of the preset diagnostic enabling conditions, the system will execute the corresponding diagnostic program. By making a comprehensive judgment based on multiple diagnostic enabling conditions, it is possible to ensure accurate fault diagnosis at the appropriate time and conditions, which helps improve the accuracy and reliability of diagnosis, reduce the possibility of misdiagnosis and missed diagnosis. At the same time, it also helps optimize the operating state of the engine and improve the performance and reliability of the engine.

[0035] Setting three key diagnostic enabling condition messages, and when they are all met to meet the requirements of the preset diagnostic enabling conditions, the system will execute the corresponding diagnostic program, which can further improve the accuracy and reliability of diagnosis. The variable valve timing (VVT) mechanism is in a normal working state without faults or abnormal manifestations, which is usually achieved by monitoring VVT-related sensor signals and control feedback, and is a basic condition to ensure that the VVT mechanism can perform phase adjustment as expected.

[0036] During the catalyst heating condition, VVT diagnosis may be interfered because the operating state of the engine system is not the normal driving state at this time. Conducting VVT diagnosis at this time may lead to misdiagnosis. The variable valve timing control enabling condition meets the requirements of the preset control enabling condition. This condition requires that the relevant enabling conditions for VVT control (such as engine speed, load, coolant temperature, etc.) must meet the requirements of the preset control logic. These preset conditions are usually set based on the operating characteristics of the engine and the performance characteristics of the VVT mechanism to ensure VVT control at the appropriate time and conditions.

[0037] For the fault diagnosis method of the variable valve timing mechanism of this engine, by setting and strictly following these diagnosis enabling conditions, it can ensure accurate diagnosis of the VVT mechanism at the appropriate time and conditions. This helps improve the accuracy and reliability of the diagnosis, and can avoid misjudgment or unnecessary maintenance operations caused by diagnosing under unfavorable conditions. At the same time, it also helps optimize the operating state of the engine and improve the performance and reliability of the vehicle.

[0038] Another object of the present invention is to propose a fault diagnosis device for a variable valve timing mechanism of an engine. The device includes:

[0039] An acquisition module for acquiring the actual variable valve timing phase angle;

[0040] A calculation module for calculating the actual variable valve timing energy value and the target variable valve timing energy value respectively according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle;

[0041] A diagnosis module for determining the fault diagnosis result of the variable valve timing mechanism of the engine according to the actual variable valve timing energy value and the target variable valve timing energy value;

[0042] Wherein, the target variable valve timing energy value is the accumulated value of the squares of the target variable valve timing phase angle gradients within a preset time, and the actual variable valve timing energy value is the accumulated value of the squares of the actual variable valve timing phase angle gradients within the preset time.

[0043] The fault diagnosis device for the variable valve timing mechanism of the engine of the present invention can implement the aforementioned fault diagnosis method of the variable valve timing mechanism of the engine. When applied to a vehicle, it is beneficial to improve the accuracy and reliability of the diagnosis result of the variable timing mechanism on the vehicle, can solve the situation where the variable valve timing mechanism cannot be completed due to the fixed operating conditions of the engine in a hybrid vehicle, and is beneficial to enhancing the diagnostic robustness.

[0044] Another object of the present invention is to provide a computer-readable medium, on which a computer program is stored, and when the computer program is executed, it can implement the fault diagnosis method for the engine variable valve timing mechanism as described above.

[0045] Meanwhile, another object of the present invention is to provide a vehicle, which is provided with a memory and a processor. A computer program is stored on the memory, and when the processor executes the computer program, it can implement the fault diagnosis method for the engine variable valve timing mechanism as described above.

[0046] For the vehicle of the present invention, by applying a controller that can implement the fault diagnosis method for the above engine variable valve timing mechanism, it is beneficial to improve the accuracy and reliability of the diagnosis result of the variable timing mechanism, thereby facilitating the safe and reliable operation of the engine and improving the safety and fuel economy of vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings that form a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0048] Figure 1 It is an exemplary flowchart of the fault diagnosis method for the engine variable valve timing mechanism according to an exemplary embodiment of the present invention;

[0049] Figure 2 It is an exemplary flowchart of the fault diagnosis method for the engine variable valve timing mechanism according to another exemplary embodiment of the present invention;

[0050] Figure 3 It is an exemplary flowchart of determining the fault diagnosis result of the engine variable valve timing mechanism according to the ratio in the present invention;

[0051] Figure 4 It is an exemplary flowchart of the fault diagnosis method for the engine variable valve timing mechanism according to still another exemplary embodiment of the present invention;

[0052] Figure 5 It is an exemplary block diagram of the fault diagnosis device for the engine variable valve timing mechanism according to an exemplary embodiment of the present invention;

[0053] Figure 6 It is an exemplary block diagram of the electronic device according to an embodiment of the present invention.

[0054] Description of the reference numerals:

[0055] 1. Acquisition module; 2. Calculation module; 3. Diagnosis module; 4. Electronic device;

[0056] 401. Memory; 402. Processor; 403. Communication interface. Detailed implementation manners

[0057] It should be noted that, under the condition of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0058] In the description of the present invention, it should be noted that, based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0059] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific situations.

[0060] The present invention will be described in detail below with reference to the drawings and in combination with embodiments.

[0061] The VVT (Variable Valve Timing) mechanism is an important component of the engine. By adjusting the VVT phase angle, the opening and closing times of the intake valve and the exhaust valve change with the change of the engine speed, so as to improve the charging efficiency, increase the engine power, and ensure that the engine can maintain the best operating state under various working conditions. Therefore, it is widely used in the vehicle models equipped with engines by major OEMs (Original Equipment Manufacturers).

[0062] The working principle of the variable valve timing technology is based on a set of complex control and execution systems, which usually include components such as an oil control valve (OCV) and a variable camshaft phaser (VCT). When the engine working condition changes, the electronic control system calculates and adjusts the opening and closing of the oil control valve according to the sensor signals, thereby controlling the oil flow to the variable camshaft phaser. Under the action of the oil pressure, the camshaft rotates a certain angle relative to the crankshaft, and then adjusts the valve timing.

[0063] If the VVT mechanism malfunctions, it may lead to inaccurate intake calculation and abnormal air-fuel mixture. In the field of OBD (On Board Diagnostics), to ensure the stable operation and efficient performance of the engine, it is required to monitor the response rate of the VVT mechanism to improve the reliability and durability of the engine. The response rate of the VVT mechanism refers to the angle that the VVT mechanism can adjust the camshaft to rotate within a unit time, which can directly reflect the adaptability of the VVT mechanism to changes in engine operating conditions.

[0064] The target opening of VVT refers to the ideal position of valve timing set by the ECU (Engine Control Unit) according to the current engine operating conditions (such as engine speed, load, etc.). This position is calculated by the ECU through a series of algorithms to optimize the combustion efficiency, power output, and fuel economy of the engine. If the actual opening (actual phase angle) fails to follow the target opening (target phase angle), a corresponding response fault will be reported.

[0065] In existing hybrid vehicle models, since the engine mainly operates in the medium and high load regions, the engine needs to output a large amount of power and torque to meet the requirements of vehicle acceleration, climbing, etc. In this case, the target opening of the engine variable valve timing mechanism basically remains unchanged to ensure the stability and efficiency of the engine. In the low load region, the engine load is small and does not require excessive power output. To save fuel and reduce emissions, the target angle of the engine variable valve timing mechanism will move towards the reference position, that is, adjust the valve timing to optimize the combustion process.

[0066] The diagnosis process of the engine variable valve timing mechanism needs to be carried out when the engine is running. However, during the actual diagnosis process, when the engine is in the low load region and the target angle moves towards the reference position, it may encounter the situation where the engine has stopped, which results in the inability to complete the fault diagnosis of the engine variable valve timing mechanism, and the corresponding IUPR molecule cannot increase, affecting the diagnostic rate of the engine variable valve timing mechanism diagnosis.

[0067] This embodiment relates to a fault diagnosis method for an engine variable valve timing mechanism. By changing the specific diagnosis process, the fault diagnosis of the VVT mechanism can be successfully completed regardless of whether the engine operating conditions of the hybrid vehicle model are in the medium and high load regions or the low load region, and the diagnostic robustness can also be enhanced.

[0068] Based on the above design concept, an exemplary structure of the fault diagnosis method for the engine variable valve timing mechanism in this embodiment is as Figure 1 shown. Generally speaking, an exemplary flowchart of the fault diagnosis method for the engine variable valve timing mechanism in this embodiment is asFigure 1 As shown in Figure 1 , it mainly includes the following specific diagnosis processes. Generally speaking, the specific diagnosis process includes steps S101 to S103.

[0069] Step S101: Obtain the actual variable valve timing phase angle.

[0070] Step S102: Calculate the actual variable valve timing energy value and the target variable valve timing energy value respectively according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle.

[0071] Step S103: Determine the fault diagnosis result of the engine variable valve timing mechanism according to the actual variable valve timing energy value and the target variable valve timing energy value.

[0072] It should be noted that the target variable valve timing energy value is the cumulative value of the squares of the target variable valve timing phase angle gradients within a preset time, and the actual variable valve timing energy value is the cumulative value of the squares of the actual variable valve timing phase angle gradients within the preset time. Specifically, the target variable valve timing energy value is calculated based on the target variable valve timing phase angle (i.e., the ideal valve opening or closing time) set by the engine management system.

[0073] Specifically, it is obtained by squaring the gradient of the target variable valve timing phase angle (i.e., the rate of change of the phase angle with time), and then accumulating these squared values. This energy value can reflect the "energy" or "power" of the valve timing change under ideal conditions.

[0074] The actual variable valve timing energy value is calculated based on the variable valve timing phase angle during the actual operation of the engine. The calculation method is the same as that of the target energy value, that is, by squaring and accumulating the gradients of the actual phase angles. And this energy value can reflect the "energy" of the valve timing change during actual operation.

[0075] For the fault diagnosis method of the engine variable valve timing mechanism in this embodiment, since the gradients of the variable valve timing phase angles within multiple unit times are squared and the squares are accumulated, the abnormal data in the fault diagnosis process of the variable valve timing mechanism can be significantly amplified. Compared with the existing method of directly using the absolute value of the angle change for judgment, the accuracy of fault diagnosis can be greatly improved.

[0076] For example, if the target variable valve timing phase angle suddenly changes by 5° within 10 ms, according to the fault diagnosis method of this embodiment, 5° needs to be squared to get 25°. If the actual variable valve timing phase angle suddenly changes by 4.5° within 10 ms, after squaring 4.5°, 20.25° is obtained. The numerical deviation between the target variable valve timing energy and the actual variable valve timing energy can reach 4.75. Based on these data in the subsequent calculation process, the accuracy of judgment can be significantly improved.

[0077] If the existing method is still used for calculation, the numerical deviation between the target variable valve timing phase angle and the actual variable valve timing phase angle is only 0.5, and 0.5 is much smaller than 4.75. The accuracy of the existing fault diagnosis method is much lower than that of the fault diagnosis method of this embodiment.

[0078] It should also be noted that the target variable valve timing phase angle can be obtained from the ECU (Engine Control unit), for example, it can be obtained by looking up a preset MAP graph (ignition control curve graph). The actual variable valve timing phase angle refers to the angular difference between the camshaft and the crankshaft rotation positions in the engine, which can be obtained and calculated, for example, through a crankshaft position sensor and a cam position sensor, or can be obtained from the ECU.

[0079] It should be understood that the acquisition methods of the target variable valve timing phase angle and the actual variable valve timing phase angle, in addition to the above-described methods, can also refer to the methods in other existing technologies. For example, the target variable valve timing phase angle can also be obtained by correcting after looking up the existing control strategy, and the acquisition method of the actual variable valve timing phase angle can be obtained from the detection sensor of the variable valve timing phase angle and calculated and processed according to the existing method for the output signal of the sensor.

[0080] In addition, the preset time mentioned in this embodiment is the time determined through experiments or calibrations. For example, it can be 4 s as described below, and it is specifically determined according to experiments or calibrations.

[0081] Next, with reference to Figure 4 shown below, we will take actual numerical values as examples to simply illustrate the calculation process of the actual variable valve timing energy value and the target variable valve timing energy value.

[0082] Assume that the target requires the variable valve timing phase angle to change from 30° to -10° within 4 s, that is, the change amount of the variable valve timing phase angle within 4 s is 40°. Assume that at this time, the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold.

[0083] According to the MAP diagram, the target variable valve timing phase angle at each moment can be queried, and the actual variable valve timing phase angle can be obtained from the engine controller. Since the calculation methods of the target variable valve timing mechanism energy value and the actual variable valve timing mechanism energy value are the same, the target variable valve timing mechanism energy value will be taken as an example for illustration below.

[0084] Suppose the target variable valve timing phase angle needs to be adjusted by 5° within 10 ms, and 5° is the change amount of the target variable valve timing phase angle within this time period, that is, the gradient. And within the next 10 ms, it needs to be adjusted by 6°, and 6° is the change amount of the target variable valve timing phase angle within this time period, that is, the gradient.

[0085] Within 4 s, after squaring 5, the square of the target variable valve timing phase angle gradient within the first unit time such as 10 ms is 25. After squaring 6, the square of the target variable valve timing phase angle gradient within the next unit time such as 10 ms is 36, and so on for subsequent times.

[0086] Accumulate the squares of the target variable valve timing phase angle gradients obtained within 4 s, such as the sum of 25 plus 36 plus the subsequent respective values. The sum of this obtained value is the target variable valve timing energy value within the preset time.

[0087] The actual variable valve timing energy value, that is, the accumulated value of the squares of the actual variable valve timing phase angle gradients. Specifically, the actual variable valve timing phase angle at each moment can be obtained through the data detected by the crankshaft sensor and the camshaft sensor, so as to facilitate the calculation of the squares of the variable valve timing phase angle gradients within each unit time, and further facilitate the calculation of the actual variable valve timing energy value within the preset time.

[0088] In step S103, specifically, it can be calculated based on the actual variable valve timing energy value and the target variable valve timing energy value according to a preset algorithm to obtain a calculation result. This calculation result can be used to quantify the deviation between the actual valve timing and the ideal valve timing. At the same time, in step S103, according to the obtained calculation result, it can be judged whether there is a fault in the engine variable valve timing mechanism.

[0089] The advantage of this fault diagnosis method for the engine variable valve timing mechanism is that it can provide a way to quantitatively evaluate the performance of the engine variable valve timing mechanism. Instead of relying solely on qualitative observations or simple threshold comparisons, it is based on the calculation result obtained from the target energy value and the actual energy value. This calculation method can more accurately identify potential faults, thereby helping to improve the reliability and performance of the engine.

[0090] Refer to Figure 1 andFigure 2 As shown, as a preferred embodiment, based on the actual variable valve timing phase angle and the preset target variable valve timing phase angle, the actual variable valve timing energy value and the target variable valve timing energy value are calculated respectively. That is, the steps in step S102 above specifically include step S1021.

[0091] Step S1021: Under the condition that the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, calculate the target variable valve timing energy value based on the target variable valve timing phase angle, and calculate the actual variable valve timing energy value based on the actual variable valve timing phase angle.

[0092] It should be noted that the prerequisite for the execution of step S1021 is that the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, which is mainly considered for the following factors.

[0093] This method can ensure the effectiveness and accuracy of subsequent calculations and diagnoses. During the actual operation of the engine variable valve timing mechanism, due to the influence of various factors (such as sensor errors, actuator delays, etc.), there may be slight phase angle fluctuations in the variable valve timing mechanism. If these fluctuations are included in the calculation range, it may lead to inaccurate calculation results of the energy value and even cause misjudgment. Therefore, by setting a preset phase angle change amount threshold, these slight fluctuations can be filtered out to ensure the stability and accuracy of the calculation and diagnosis.

[0094] For the fault diagnosis method of the engine variable valve timing mechanism in this embodiment, only when the target variable valve timing phase angle changes significantly, the corresponding energy value is calculated, which helps to more truly reflect the change of the working state of the engine variable valve timing mechanism, thereby facilitating the improvement of the accuracy and reliability of the calculation and diagnosis.

[0095] In existing vehicles applying hybrid power systems, during the diagnosis of the engine variable valve timing mechanism, it is necessary to rely on working condition coordination requests, such as fuel cut-off conditions or the HCU (Hydraulic Control Unit) to adjust the engine working conditions, which has a relatively high dependence on the working conditions and may conflict with emissions and fuel consumption during the development process, and the diagnostic robustness is low.

[0096] The change amount of the target variable valve timing phase angle in this embodiment refers to the change amount of the target variable valve timing phase angle within a unit time. This data can indicate that the variable valve timing (VVT) system is undergoing a significant adjustment state. Conducting the diagnosis of the engine variable valve timing mechanism in this state is beneficial to improving the accuracy and reliability of the diagnosis, has a low dependence on the working conditions, and has high diagnostic robustness.

[0097] As Figure 2 shown, as a preferred embodiment, according to the actual variable valve timing energy value and the target variable valve timing energy value, determine the fault diagnosis result of the engine variable valve timing mechanism, that is, step S103 specifically includes step S1031 and step S1032.

[0098] Step S1031, divide the actual variable valve timing energy value by the target variable valve timing energy value to obtain the ratio of the variable valve timing phase angle change energy value.

[0099] Step S1032, determine the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy value.

[0100] It should be understood that in step S1031 above, the obtained result is the ratio of the actual value to the target value of the variable valve timing phase angle change energy value, and this ratio can reflect the degree of closeness between the actual performance and the target performance.

[0101] In step S1032, based on the ratio of the actual value to the target value of the energy value, determine the fault diagnosis result of the engine variable valve timing mechanism. This method can present the performance of the engine variable valve timing mechanism in a quantitative manner, thereby more accurately evaluating the working state of the engine variable valve timing mechanism. Compared with the traditional qualitative evaluation method, this method is more accurate and has many advantages such as being conducive to improving the diagnostic accuracy, enhancing the diagnostic efficiency, and enhancing the engine performance.

[0102] From Figure 2 Combined with Figure 3 shown, as a preferred embodiment, according to the ratio of the variable valve timing phase angle change energy value, determine the fault diagnosis result of the engine variable valve timing mechanism, that is, step S1032 specifically includes step S10321.

[0103] Step S10321, under the condition that the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold, preliminarily determine that the engine variable valve timing mechanism has no fault.

[0104] In step S10321, by the ratio of the variable valve timing phase angle change energy value being greater than the preset ratio threshold, preliminarily determine that the engine variable valve timing mechanism is in a normal working state, which can avoid unnecessary in-depth inspections and diagnoses, greatly improve the diagnostic efficiency, shorten the repair time, and by setting a reasonable preset ratio threshold, this is conducive to improving the diagnostic accuracy and reliability.

[0105] In a preferred embodiment, the preset ratio threshold is preferably between 0.8 and 0.99, such as 0.8, 0.85, 0.9, 0.95, etc. According to calibration or tests, other values can of course be adopted for the preset ratio threshold. It should be understood that the higher the preset ratio threshold is set, the more stringent the performance requirements for the engine variable valve timing mechanism are. The preset ratio threshold is usually obtained based on a large amount of experimental data and experience summary, and can relatively accurately reflect the normal working state of the variable valve timing mechanism, and is specifically determined according to calibration or tests.

[0106] In the above text, the ratio of the obtained variable valve timing phase angle change energy value can relatively accurately evaluate the performance of the variable valve timing mechanism. If the ratio of the variable valve timing phase angle change energy value is close to 1, it indicates that the actual variable valve timing energy value is very close to the target variable valve timing energy value, indicating that the variable valve timing mechanism is working properly and the variable valve timing mechanism can normally follow the target phase angle.

[0107] If the ratio of the variable valve timing phase angle change energy value is less than the preset ratio threshold, it indicates that the variable valve timing mechanism fails to reach the expected energy level, which may be due to reasons such as slow mechanism response, control signal problems, or component damage, indicating that there may be a fault in the variable valve timing mechanism.

[0108] Still referring to Figure 2 and Figure 3 As shown in, as a preferred embodiment, according to the ratio of the variable valve timing phase angle change energy value, the fault diagnosis result of the engine variable valve timing mechanism is determined, that is, step S1032 further includes step S10322 and step S10323.

[0109] Step S10322, according to the determination result of initially determining that there is no fault in the engine variable valve timing mechanism, count the cumulative number of times that there is no fault in the variable valve timing mechanism within the preset time.

[0110] Step S10323, when the cumulative number of times reaches the preset number threshold, finally determine that there is no fault in the engine variable valve timing mechanism.

[0111] It should be noted that in step S10322, the preset time refers to a time. In a preferred embodiment, the preset time is between 3 s and 5 s, such as 3 s, 4 s, 5 s, etc. Within the preset time, each time the engine variable valve timing mechanism is inspected and diagnosed, the judgment result needs to be recorded. If it is determined that there is no fault according to the ratio, a result of "no fault" is recorded once.

[0112] Specifically, the cumulative number of times the variable valve timing mechanism is fault-free can be accumulated using a counter or database for the number of fault-free times recorded within a preset time. Each time the "fault-free" result is recorded, the counter is incremented by one.

[0113] The preset time and the number threshold need to be reasonably set according to the specific model of the engine, operating conditions, and maintenance experience. Setting them too loosely may lead to misjudgment, while setting them too strictly may increase unnecessary maintenance costs. In addition, before the cumulative number reaches the preset number threshold, it is necessary to continuously monitor the operating state of the VVT mechanism.

[0114] In step S10323, within a preset time, that is, within a certain time period, the cumulative number of fault-free times is statistically analyzed, and based on the cumulative number of times the variable valve timing mechanism is fault-free during this period, the stability and reliability of the engine's variable valve timing mechanism during this period can be understood. Using this data as the final criterion for determining that the engine's variable valve timing mechanism is fault-free is conducive to improving the accuracy and reliability of fault diagnosis.

[0115] From Figure 2 Combined with Figure 4 As shown, as a preferred implementation manner, according to the ratio of the variable valve timing phase angle change energy values, the fault diagnosis result of the engine's variable valve timing mechanism is determined. That is, step S1032 further includes: under the condition that the ratio of the variable valve timing phase angle change energy values is less than or equal to a preset ratio threshold, steps S101 to S103 are re-executed.

[0116] When the ratio of the variable valve timing phase angle change energy values is less than or equal to the preset ratio threshold, it indicates that there is a large deviation between the actual performance and the target performance of the engine's variable valve timing (VVT) mechanism. This may be caused by faults, wear, improper adjustment, or other external factors of the VVT mechanism. At this time, re-executing steps S101 to S103 to obtain the actual variable valve timing phase angle and the target variable valve timing phase angle is convenient for performing subsequent steps, thus facilitating the calculation of new actual variable valve timing energy values and target variable valve timing energy values, which is a reasonable diagnostic step.

[0117] Under the condition that the ratio of the variable valve timing phase angle change energy values is less than or equal to the preset ratio threshold, re-executing the following steps to obtain the actual variable valve timing phase angle, that is, re-acquiring data and performing calculations, helps to reduce misjudgment caused by single measurement errors or instrument failures. By performing multiple calculations and comparisons, more abundant data can be obtained, thereby more accurately evaluating the health status of the VVT mechanism. This helps technicians more comprehensively understand the performance state of the VVT mechanism and provides a more reliable basis for maintenance decisions.

[0118] Reference Figure 4 As shown, as a preferred embodiment, before obtaining the actual variable valve timing phase angle, that is, before step S101, the fault diagnosis method of the engine variable valve timing mechanism of this embodiment further includes the following diagnostic enable condition judgment steps.

[0119] The diagnostic enable condition judgment steps specifically include: obtaining diagnostic enable condition information, then judging whether the diagnostic enable condition information meets the preset requirements, and then obtaining the actual variable valve timing phase angle when the diagnostic enable condition information meets the preset requirements.

[0120] That is to say, only when the diagnostic enable condition information meets the preset requirements, will the specific diagnostic steps in the fault diagnosis method of the engine variable valve timing mechanism of this embodiment be executed, will step S101 be executed, and then steps S102 and S103 will be continued.

[0121] Under normal circumstances, the diagnostic enable condition information is preferably multiple. In this step, it is an important link in the fault diagnosis of the engine variable valve timing mechanism to determine whether each diagnostic enable condition simultaneously meets the preset requirements based on multiple diagnostic enable condition information.

[0122] The diagnostic enable conditions refer to a series of prerequisite conditions that need to be met before performing engine fault diagnosis. These conditions are usually related to the operating state of the engine variable valve timing mechanism, environmental parameters, and the state of the diagnostic system. Only when these diagnostic enable conditions simultaneously meet the preset requirements can the diagnostic system effectively perform fault diagnosis on the engine variable valve timing mechanism.

[0123] The preset diagnostic enable conditions are a series of specific conditions or criteria set according to each diagnostic enable condition. The setting of these conditions or criteria facilitates the diagnostic system to smoothly perform fault diagnosis on the engine variable valve timing mechanism.

[0124] As a preferred embodiment, the diagnostic enable condition information includes at least one of the state information of the variable valve timing mechanism, the starting condition of the vehicle, and the control enable state of the variable valve timing system. The preset requirements include that the variable valve timing mechanism has no fault, the vehicle starting condition is not in the catalyst heating condition, and the control enable state of the variable valve timing system is the preset state.

[0125] That is to say, the diagnostic enable condition information includes, for example, the state information of the variable valve timing mechanism, or includes the starting condition of the vehicle, or includes the control enable state of the variable valve timing system. In addition, the diagnostic enable condition information may also include any two of the three, or simultaneously include these three diagnostic enable condition information.

[0126] It should be noted that in this embodiment, in a preferred implementation manner, multiple diagnostic enabling conditions are set, and preset diagnostic enabling conditions are set for each diagnostic enabling condition, which is conducive to ensuring the smooth and reliable operation of the fault diagnosis method for the engine variable valve timing mechanism, and is conducive to improving the reliability and accuracy of diagnosis.

[0127] Among them, the variable valve timing mechanism is free of faults, which means that through relevant sensors and diagnostic logic, it can be basically judged that the variable valve timing mechanism (VVT) is in a normal working state without faults or abnormalities. The method for determining whether the variable valve timing mechanism is free of faults can specifically refer to existing methods.

[0128] The vehicle starting condition generally refers to the process from engine start to reaching a stable operating state. The catalyst heating condition refers to a series of measures taken during the vehicle cold start process to quickly bring the catalyst (such as a three-way catalytic converter) in the emission control system to an effective operating temperature. During this process, the catalyst can be heated to a reasonable temperature using energy outside the catalyst body, enabling the catalyst to efficiently convert exhaust gases when the vehicle starts.

[0129] The main purpose of catalyst heating is to reduce pollutant emissions during the vehicle cold start phase. When the vehicle is cold started, the catalyst temperature is low and the catalytic conversion efficiency is not high, resulting in higher pollutant emissions. By heating the catalyst, the operating temperature of the catalyst can be rapidly increased, enabling the catalyst to quickly reach the optimal catalytic conversion efficiency, thereby reducing pollutant emissions.

[0130] The catalyst heating condition is usually affected by various factors, such as engine speed and engine load. The higher the engine speed, the greater the exhaust gas flow rate, and the faster the catalyst heating speed. And the greater the engine load, the higher the exhaust gas temperature, which also helps to quickly heat the catalyst.

[0131] In the fault diagnosis method of this embodiment, the catalyst heating condition is excluded because during the catalyst heating condition, the engine management system may take a series of special measures (such as delaying ignition, adjusting the air-fuel ratio, etc.) to accelerate the catalyst heating process. And these measures may change the normal operating state of the engine. Due to the change in the engine operating state, the fault manifestations of the engine variable valve timing mechanism may not be obvious or may be masked, which will affect the performance of the engine variable valve timing mechanism.

[0132] While in non-catalyst heating conditions, the engine is usually in a relatively stable operating state. Selecting to perform fault diagnosis on the engine variable valve timing mechanism under non-catalyst heating conditions can more accurately reflect the actual performance of the engine variable valve timing mechanism, thereby avoiding interference during the diagnosis process and being conducive to improving the accuracy and reliability of the engine variable valve timing mechanism fault diagnosis.

[0133] The enabling conditions for variable valve timing control generally include engine speed, water temperature, oil temperature, battery voltage, sensors, and each actuator. Among them, engine speed is an important factor affecting variable valve timing control. Within a specific speed range, the variable valve timing system can more effectively adjust the opening and closing timing of the valves, thereby optimizing the performance and efficiency of the engine.

[0134] It should be noted that the oil temperature here refers to the engine oil temperature. In a preferred embodiment, the range of the engine oil temperature is between -10°C and 120°C. If the engine oil temperature exceeds this range, it indicates that there may be an abnormality in the engine system, and the engine variable valve timing mechanism fault diagnosis method of this embodiment does not need to be executed.

[0135] The temperature and state of the engine cooling system and lubrication system also affect the control effect of the variable valve timing system. Generally, at appropriate water temperature and oil temperature, the variable valve timing system can more accurately adjust the valve timing. The stability of the battery voltage is crucial for the normal operation of the variable valve timing system. Insufficient or unstable voltage may cause the system to fail to operate normally or have poor control effect.

[0136] The variable valve timing system needs to rely on various sensors to monitor the operating state of the engine, such as the camshaft position sensor, crankshaft position sensor, etc. The accuracy and reliability of these sensors are crucial for the normal operation of the system. The actuators of the variable valve timing system include solenoid valves, variable camshaft phasers, etc. The normal operation of these components is the key to realizing variable valve timing control.

[0137] Whether each enabling condition of the variable valve timing control meets the requirements of the preset control enabling conditions can be judged by referring to the methods of the prior art. The reason for judging whether each enabling condition of the variable valve timing control meets the requirements of the preset control enabling conditions is that these conditions can jointly ensure that the variable valve timing system can accurately and effectively adjust the opening and closing timing of the valves, thereby facilitating the improvement of the accuracy and reliability of diagnosis.

[0138] It should also be noted that determining whether the diagnostic enabling conditions simultaneously meet the preset diagnostic enabling conditions means that each diagnostic enabling condition respectively meets the requirements of the corresponding preset diagnostic enabling conditions, and all diagnostic enabling conditions must simultaneously meet the requirements of the corresponding preset diagnostic enabling conditions.

[0139] Specifically, the diagnostic enabling conditions and the requirements of the preset diagnostic enabling conditions are in one-to-one correspondence. If each diagnostic enabling condition meets the requirements of the corresponding preset diagnostic enabling conditions, it can be determined that each diagnostic enabling condition simultaneously meets the preset diagnostic enabling conditions.

[0140] The fault diagnosis method for the engine variable valve timing mechanism in this embodiment obtains a calculation result based on the actual variable valve timing energy value and the target variable valve timing energy value, and determines the fault diagnosis result of the engine variable valve timing mechanism based on this calculation result.

[0141] In this method, since the data for diagnosis is the actual variable valve timing energy value and the target variable valve timing energy value, compared with the existing method of directly judging using angle values, the accuracy and diagnosis rate of the diagnosis result can be improved, the situation where the variable valve timing mechanism cannot be completed due to the fixed operating conditions of the hybrid vehicle engine can be solved, and it is beneficial to enhance the diagnostic robustness.

[0142] To better understand the fault diagnosis method for the engine variable valve timing mechanism in this embodiment, next, with reference to Figure 4 an exemplary flowchart shown below, a detailed description of one exemplary diagnosis method will be given.

[0143] For the fault diagnosis method of the engine variable valve timing mechanism in this embodiment, after starting, it is necessary to first determine whether the diagnostic enable condition information simultaneously meets the preset requirements. Under the condition that each diagnostic enable condition information simultaneously meets the preset requirements, the subsequent diagnostic steps are continued, while under the condition that each diagnostic enable condition does not simultaneously meet the preset diagnostic enable conditions, the subsequent steps do not need to be executed.

[0144] Specifically, under the condition that each diagnostic enable condition simultaneously meets the preset diagnostic enable conditions, in the next step, when the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, it is necessary to calculate the actual variable valve timing energy value and the target variable valve timing energy value.

[0145] In other words, in this step, it is necessary to monitor the change amount of the target variable valve timing phase angle in real time. Once the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, the actual variable valve timing energy value and the target variable valve timing energy value are calculated. Under the condition that the change amount of the target variable valve timing phase angle does not exceed the preset phase angle change amount threshold, the subsequent steps do not need to be carried out.

[0146] Specifically, the calculation methods for calculating the actual variable valve timing energy value and the target variable valve timing energy value still refer to the above description and will not be elaborated here.

[0147] Next, divide the actual variable valve timing energy value by the target variable valve timing energy value to obtain the ratio of the variable valve timing phase angle change energy value, and then it is necessary to determine whether the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold.

[0148] Under the condition that the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold, the subsequent steps are continued. While under the condition that the ratio of the variable valve timing phase angle change energy value is less than the preset ratio threshold, there is no return to execute the previous steps, and continue to monitor and judge whether the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold.

[0149] Specifically, under the condition that the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold, it is preliminarily determined that the engine variable valve timing mechanism has no fault, and at the same time, the no-fault counter increases by one count.

[0150] Next, under the condition that the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold, it is finally determined that the engine variable valve timing mechanism has no fault, and the diagnostic process ends.

[0151] It should also be noted that in the fault diagnosis method of the engine variable valve timing mechanism of this embodiment, when multiple diagnostic enable condition information does not simultaneously meet the preset requirements, the alarm module can be used to alarm, prompting specific fault problems or reminding the driver to check.

[0152] In addition, at the preset time, if the cumulative number of times does not reach the preset number threshold, it can also be determined that the engine variable valve timing mechanism has a fault. At this time, the alarm module can also be used to alarm to prompt specific fault problems or remind the driver to check.

[0153] Specifically, the fault diagnosis method of the engine variable valve timing mechanism of this embodiment can be executed by an existing engine control unit, for example. When the engine variable valve timing mechanism fails, the engine control unit will detect this abnormality and trigger an alarm mechanism. The specific alarm method can refer to the existing technology. At this time, the engine fault light will light up to remind the driver to pay attention to the vehicle condition.

[0154] It should be noted that in another exemplary method, in step S103, in addition to calculating the ratio using the method of step S1031, for example, the target variable valve timing energy value can also be subtracted from the actual variable valve timing energy value to obtain the difference value of the variable valve timing phase angle change energy value, and this difference value of the variable valve timing phase angle change energy value can be used as the calculation result.

[0155] And at this time, step S103 does not include the aforementioned step S1032, but includes the following steps, determining the fault diagnosis result of the engine variable valve timing mechanism based on the difference value of the variable valve timing phase angle change energy value.

[0156] When determining whether the engine variable valve timing mechanism can work properly based on the difference in the variable valve timing phase angle change energy value, specifically, it can be determined whether the difference in the variable valve timing mechanism phase angle change energy value is greater than a preset difference threshold. Under the condition that the difference in the variable valve timing mechanism phase angle change energy value is less than the preset difference threshold, it can be preliminarily determined that the engine variable valve timing mechanism is free of faults.

[0157] In addition, under the condition that the difference in the variable valve timing mechanism phase angle change energy value is greater than the preset difference threshold, step S101 can be repeatedly executed to obtain the actual variable valve timing phase angle.

[0158] It should be noted that under the condition that the difference in the variable valve timing mechanism phase angle change energy value is less than the preset difference threshold, after preliminarily determining that the engine variable valve timing mechanism is free of faults, the method may further include the aforementioned step S10322. According to the determination result of preliminarily determining that the engine variable valve timing mechanism is free of faults, the cumulative number of times the variable valve timing mechanism is free of faults within a preset time is counted, and when the cumulative number reaches the preset number threshold, it is finally determined that the engine variable valve timing mechanism is free of faults.

[0159] It should be understood that through the difference in the variable valve timing phase angle change energy value, the performance of the variable valve timing mechanism can also be accurately evaluated. If the difference in the variable valve timing phase angle change energy value is close to 0, that is, the smaller the difference in the variable valve timing phase angle change energy value, it indicates that the actual variable valve timing energy value is very close to the target variable valve timing energy value, indicating that the variable valve timing mechanism is working properly and the variable valve timing mechanism can normally follow the target phase angle.

[0160] If the difference in the variable valve timing phase angle change energy value is greater than the preset difference threshold, it indicates that the variable valve timing mechanism fails to reach the expected energy level, which may be due to reasons such as slow mechanism response, control signal problems, or component damage, indicating that the variable valve timing mechanism may have a fault.

[0161] At the same time, this embodiment also provides a fault diagnosis device for an engine variable valve timing mechanism, as Figure 5 shown. In terms of the overall structure, the fault diagnosis device for the engine variable valve timing mechanism mainly includes an acquisition module 1, a calculation module 2 connected to the acquisition module 1, and a diagnosis module 3 connected to the calculation module 2.

[0162] Among them, the acquisition module 1 is used to acquire the actual variable valve timing phase angle, that is, the acquisition module 1 is used to execute the aforementioned step S101.

[0163] The calculation module 2 is used to calculate the actual variable valve timing energy value and the target variable valve timing energy value respectively according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle, and obtain the calculation result after calculation according to the preset algorithm. That is, the calculation module 2 is used to implement the foregoing step S102.

[0164] The diagnosis module 3 is used to determine the fault diagnosis result of the engine variable valve timing mechanism according to the actual variable valve timing energy value and the target variable valve timing energy value. That is, the diagnosis module 3 is used to implement the foregoing step S103.

[0165] Specifically, the calculation module 2 is further used to implement the foregoing step S1021. Under the condition that the change amount of the target variable valve timing phase angle exceeds the preset phase angle change amount threshold, based on the target variable valve timing phase angle, calculate the target variable valve timing energy value, and based on the actual variable valve timing phase angle, calculate the actual variable valve timing energy value.

[0166] The diagnosis module 3 is further used to implement the foregoing step S1031, divide the actual variable valve timing energy value by the target variable valve timing energy value to obtain the ratio of the variable valve timing phase angle change energy value. The diagnosis module 3 is further used to implement the foregoing step S1032, and determine the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy value.

[0167] In addition, the diagnosis module 3 is specifically further used to implement the foregoing steps S10321 to S10323.

[0168] Step S10321, under the condition that the ratio of the variable valve timing phase angle change energy value is greater than the preset ratio threshold, preliminarily determine that the engine variable valve timing mechanism has no fault.

[0169] Step S10322, according to the determination result that the engine variable valve timing mechanism is preliminarily determined to have no fault, count the cumulative number of times that the variable valve timing mechanism has no fault within the preset time.

[0170] Step S10323, when the cumulative number of times reaches the preset number threshold, finally determine that the engine variable valve timing mechanism has no fault.

[0171] In addition, the diagnosis module 3 is further used to implement the foregoing diagnosis enable condition judgment process. Specifically, the diagnosis enable condition judgment process includes obtaining diagnosis enable condition information, judging whether the diagnosis enable condition information meets the preset requirements, and obtaining the actual variable valve timing phase angle when the diagnosis enable condition information meets the preset requirements.

[0172] Specifically, the diagnosis module 3 is further configured to implement the following steps. When the following conditions are simultaneously met: the variable valve timing mechanism is free of faults, the vehicle starting condition is not in the catalyst heating condition, and the control enabling state of the variable valve timing system is in a preset state, it is determined that the diagnosis enabling condition information meets the preset requirements.

[0173] The fault diagnosis device for the engine variable valve timing mechanism according to this embodiment can implement the aforementioned fault diagnosis method for the engine variable valve timing mechanism. When applied to a vehicle, it is beneficial to improve the accuracy and reliability of the diagnosis results of the variable timing mechanism on the vehicle, can solve the situation where the variable valve timing mechanism cannot be completed due to the fixed operating conditions of the engine in hybrid vehicle models, and is beneficial to enhancing the diagnostic robustness.

[0174] Meanwhile, this embodiment also relates to a vehicle, which is provided with a memory 401 and a processor 402. When the processor 402 executes the computer program stored on the memory 401, it can implement the aforementioned fault diagnosis method for the engine variable valve timing mechanism.

[0175] For the vehicle according to this embodiment, by applying a controller that can implement the aforementioned fault diagnosis method for the engine variable valve timing mechanism, it is beneficial to improve the accuracy and reliability of the diagnosis results of the variable timing mechanism, thereby facilitating the safe and reliable operation of the engine and improving the safety and fuel economy of vehicle driving.

[0176] It should be noted that, as Figure 6 shown, the aforementioned memory 401 and processor 402 can be integrated into the same electronic device 4. As a preferred implementation manner, the electronic device 4 further includes a communication interface 403, which is used for communication between the memory 401 and the processor 402.

[0177] Specifically, the memory 401 in this embodiment can be used to store a computer program that can run on the processor 402, and specifically adopts the following computer-readable medium. The memory 401 may include a high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0178] If the memory 401, the processor 402, and the communication interface 403 are implemented independently, the communication interface 403, the memory 401, and the processor 402 can be interconnected via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus can be divided into an address bus, a data bus, a control bus, and the like.

[0179] For ease of representation, Figure 6 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus. In a preferred embodiment, in a specific implementation, if the memory 401, the processor 402, and the communication interface 403 are integrated on a single chip, the memory 401, the processor 402, and the communication interface 403 can communicate with each other through an internal interface.

[0180] The processor 402 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0181] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application.

[0182] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0183] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logical function or process. The scope of the preferred embodiments of this application includes additional implementations, where functions can be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of this application pertain.

[0184] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with these instruction execution systems, apparatuses, or devices.

[0185] Meanwhile, this embodiment also relates to a computer-readable medium on which a computer program is stored, and when the computer program is executed on a processor, it can implement the above-mentioned fault diagnosis method for the engine variable valve timing mechanism.

[0186] For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM).

[0187] In addition, a computer-readable medium can even be paper or other suitable media on which a program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0188] It should be understood that each part of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, any one or a combination of the following technologies well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0189] Through the description of the above embodiments, those skilled in the art can understand that, for the convenience and brevity of description, only the above division of each functional module is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0190] In the embodiments provided in the present application, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0191] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fault diagnosis method for a variable valve timing mechanism of an engine, characterized in that: The method comprises: Obtaining actual variable valve timing phase angle; Calculating an actual variable valve timing energy value and a target variable valve timing energy value according to the actual variable valve timing phase angle and a preset target variable valve timing phase angle; Determining a fault diagnosis result of a variable valve timing mechanism of an engine according to the actual variable valve timing energy value and the target variable valve timing energy value; Among them, the target variable valve timing energy value is the cumulative value of the square of the target variable valve timing phase angle gradient within the preset time, and the actual variable valve timing energy value is the cumulative value of the square of the actual variable valve timing phase angle gradient within the preset time.

2. The fault diagnosis method of the engine variable valve timing mechanism according to claim 1, characterized in that: The method of determining a fault diagnosis result of the variable valve timing mechanism of the engine according to the actual variable valve timing energy value and the target variable valve timing energy value comprises: Dividing the actual variable valve timing energy value by the target variable valve timing energy value to obtain a ratio of the variable valve timing phase angle change energy value; The fault diagnosis result of the engine variable valve timing mechanism is determined according to the ratio of the variable valve timing phase angle change energy values.

3. The fault diagnosis method of the engine variable valve timing mechanism according to claim 2, characterized in that: Determining the fault diagnosis result of the engine variable valve timing mechanism according to the ratio of the variable valve timing phase angle change energy value includes: Under the condition that the ratio of the variable valve timing phase angle change energy values ​​is greater than a preset ratio threshold, it is preliminarily determined that the engine variable valve timing mechanism has no faults.

4. The fault diagnosis method of the engine variable valve timing mechanism according to claim 3, characterized in that: The method of determining the fault diagnosis result of the variable valve timing mechanism of the engine according to the ratio of the energy value of the variable valve timing phase angle change also includes: According to the preliminary determination result that the variable valve timing mechanism of the engine has no fault, counting the cumulative number of times that the variable valve timing mechanism has no fault within the preset time; When the accumulated number of times reaches a preset number threshold, it is finally determined that the engine variable valve timing mechanism has no faults.

5. The fault diagnosis method of the engine variable valve timing mechanism according to claim 1, characterized in that: The actual variable valve timing energy value and the target variable valve timing energy value are calculated respectively according to the actual variable valve timing phase angle and the preset target variable valve timing phase angle, including: Under the condition that the target variable valve timing phase angle change exceeds the preset phase angle change threshold, the target variable valve timing energy value is calculated based on the target variable valve timing phase angle, and the actual variable valve timing energy value is calculated based on the actual variable valve timing phase angle.

6. The fault diagnosis method for the variable valve timing mechanism of an engine according to any one of claims 1 to 5, characterized in that: Before obtaining the actual variable valve timing phase angle, the method further includes: Obtain diagnostic enabling condition information; Determining whether the diagnosis enabling condition information meets preset requirements; When the diagnosis enabling condition information meets a preset requirement, the actual variable valve timing phase angle is obtained.

7. The fault diagnosis method of the engine variable valve timing mechanism according to claim 6, characterized in that: The diagnosis enabling condition information includes at least one of the state information of the variable valve timing mechanism, the vehicle starting condition and the variable valve timing system control enabling state; The preset requirements include that the variable valve timing mechanism has no faults, the vehicle startup condition is not in a catalyst heating condition, and the variable valve timing system control enable state is a preset state.

8. A fault diagnosis device for an engine variable valve timing mechanism, characterized in that: The device comprises: An acquisition module (1) is used to acquire an actual variable valve timing phase angle; A calculation module (2), used to calculate an actual variable valve timing energy value and a target variable valve timing energy value according to the actual variable valve timing phase angle and a preset target variable valve timing phase angle; A diagnosis module (3) for determining a fault diagnosis result of a variable valve timing mechanism of an engine according to the actual variable valve timing energy value and the target variable valve timing energy value; Among them, the target variable valve timing energy value is the cumulative value of the square of the target variable valve timing phase angle gradient within the preset time, and the actual variable valve timing energy value is the cumulative value of the square of the actual variable valve timing phase angle gradient within the preset time.

9. A computer readable medium, characterized in that: The computer readable medium stores a computer program, which, when executed, can implement the fault diagnosis method for the engine variable valve timing mechanism as described in any one of claims 1 to 7.

10. A vehicle, characterized in that: The vehicle is provided with a memory (401) and a processor (402), the memory (401) storing a computer program, and when the processor (402) executes the computer program, it is capable of implementing the fault diagnosis method of the engine variable valve timing mechanism as described in any one of claims 1 to 7.

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