Engine misfire detection method and vehicle

Abstract

The invention provides an engine misfire detection method and a vehicle. The method comprises the steps that vehicle operation data and an engine misfire signal are obtained; and according to the vehicle operation data and the engine misfire signal, whether the vehicle meets a preset predicted misfire condition or not is determined, and if the predicted misfire condition is met, a target engine cylinder is determined according to the engine misfire signal. And controlling the target engine cylinder to stop oil injection, and determining that the target engine cylinder is on fire in response to the condition that the engine fire signal after oil injection is stopped and the engine fire signal before oil injection is stopped meet a preset difference condition. By means of the method for stopping oil injection of the target engine cylinder, whether the target engine cylinder is in true misfire or false misfire can be accurately judged, and therefore the problem of misfire misjudgment of the engine cylinder is solved.

Description

Technical Field

[0001] The present application relates to the field of vehicle engine technology, and in particular to an engine misfire detection method and a vehicle. Background Art

[0002] Engine misfire will cause the engine to run less smoothly, and its power and economy will decrease. Therefore, the vehicle will monitor the engine misfire signal. When the number of misfires reaches a certain value, the misfire fault code will be reported to prompt the user to troubleshoot the engine fault. However, hybrid vehicles may have misfire fault false alarms under certain working conditions, which brings certain difficulties to misfire fault detection. Summary of the invention

[0003] In view of this, the purpose of the present application is to provide an engine misfire detection method and a vehicle to solve the problem of false alarm of vehicle misfire fault.

[0004] Based on the above objectives, the present application provides an engine misfire detection method, comprising: Obtain vehicle operation data and engine misfire signals; determining whether the vehicle satisfies a preset predicted misfire condition according to the vehicle operation data and the engine misfire signal, and if so, determining a target engine cylinder according to the engine misfire signal; The target engine cylinder is controlled to stop fuel injection, and in response to an engine misfire signal after the fuel injection is stopped and an engine misfire signal before the fuel injection is stopped satisfying a preset difference condition, it is determined that the target engine cylinder is misfiring.

[0005] By using the method of stopping the fuel injection of the target engine cylinder in the above embodiment, it is possible to accurately determine whether the target engine cylinder is in a true misfire or a false misfire, thereby eliminating the problem of misjudgment of engine cylinder misfire.

[0006] Optionally, the vehicle operation data includes engine water temperature, vehicle speed, engine operation time, engine speed, and engine load; and determining whether the vehicle meets a preset predicted misfire condition according to the vehicle operation data and the engine misfire signal includes: In response to the engine water temperature exceeding a preset water temperature threshold, the vehicle speed being less than a preset vehicle speed threshold, the engine running time exceeding a preset time, the engine speed being within a preset speed range, the engine load being within a preset load range, and the engine misfire signal continuously satisfying the misfire condition for more than a preset number of times, it is determined that the vehicle satisfies a preset predicted misfire condition.

[0007] Through the method of the above embodiment, according to the working conditions where the vehicle may have a misjudgment of a misfire fault, the vehicle operation data is reasonably limited and the predicted misfire conditions are formulated. By predicting the misfire conditions, the logic of actively activating the cylinder cut-off to eliminate the misjudged misfire cylinder is accurately and timely activated, and whether the misfire fault is a true misfire fault is identified, thereby achieving the purpose of eliminating the misjudgment of the misfire fault, avoiding the increase in the workload of the technicians for troubleshooting due to the false alarm of the engine misfire fault, and improving the user satisfaction.

[0008] Optionally, determining a target engine cylinder according to the engine misfire signal includes: For the engine misfire signals corresponding to each cylinder in the engine working cycle, the cylinder corresponding to the engine misfire signal that meets the misfire condition is used as the target engine cylinder.

[0009] Through this embodiment, the target engine cylinder can be accurately determined, cylinders that do not need further verification are eliminated, the time required to verify cylinders that may have misfire faults is reduced, and verification efficiency is improved.

[0010] Optionally, the engine misfire signal includes an engine speed change rate; and the step of using a cylinder corresponding to the engine misfire signal that satisfies the misfire condition as the target engine cylinder includes: The cylinder whose engine speed change rate exceeds a preset change rate threshold is used as the target engine cylinder.

[0011] Through the method of this embodiment, the misfire condition is reasonably formulated according to the preset misfire threshold value, thereby achieving the purpose of accurately determining the target engine cylinder.

[0012] Optionally, before controlling the target engine cylinder to stop fuel injection, the method further includes: During a plurality of engine operating cycles, it is determined whether an engine misfire signal corresponding to a target engine cylinder satisfies a preset stability condition. If the preset stability condition is satisfied, the target engine cylinder is controlled to stop fuel injection.

[0013] The method provided in this embodiment can accurately identify whether the engine misfire signal is stable, thereby ensuring subsequent accurate judgment of whether there is a misfire fault in the target engine cylinder.

[0014] Optionally, controlling the target engine cylinder to stop fuel injection includes: The target engine cylinder is controlled to stop fuel injection within a preset number of engine operating cycles.

[0015] The method of this embodiment can reasonably control the number of times the fuel injection is stopped, avoid affecting the normal driving of the vehicle due to the verification of the target engine cylinder, and complete the verification of whether there is a real misfire fault in the target engine cylinder without affecting the user's driving experience.

[0016] Optionally, the engine misfire signal includes an engine speed change rate; the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection meet a preset difference condition, including: In response to a difference between the engine speed change rate after stopping fuel injection and the engine speed change rate before stopping fuel injection being less than a preset difference threshold, it is determined that the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection meet a preset difference condition.

[0017] This embodiment can accurately determine the change amplitude of the engine misfire signal before and after the fuel injection is stopped by setting a preset difference threshold, ensure the accuracy of determining whether there is a real misfire fault in the target engine cylinder, and accurately identify the misjudgment of misfire.

[0018] Optionally, after determining the target engine cylinder according to the engine misfire signal, the method further includes: Generate a misfire flag corresponding to the target engine cylinder; After determining that the target engine cylinder misfires, the method further includes: Output the misfire flag corresponding to the target engine cylinder.

[0019] This embodiment introduces a misfire flag, which is helpful for counting the number of misfires in the engine cylinders and is also helpful for accurate control of the controller during the engine misfire detection process.

[0020] Optionally, the method further comprises: In response to the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection not satisfying a preset difference condition, it is determined that the target engine cylinder has not misfired, and the misfire flag corresponding to the target engine cylinder is removed.

[0021] When determining that the target engine cylinder has not misfired, this embodiment can effectively avoid counting false misfire faults by eliminating the misfire flag, which is beneficial to the accuracy of misfire fault statistics.

[0022] Based on the same inventive concept, the present application also provides a vehicle, the vehicle comprising: A memory for storing executable program codes; A processor is used to call and run the executable program code from the memory so that the vehicle executes the method described in the first aspect.

[0023] As can be seen from the above, the engine misfire detection method and vehicle provided by the present application include obtaining vehicle operation data and engine misfire signals. The vehicle operation data can be used to understand the vehicle's operating status, and the engine misfire signal can be used to monitor whether the vehicle has a misfire fault prompt. Determine whether the vehicle meets the preset predicted misfire conditions based on the vehicle operation data and the engine misfire signal. If the predicted misfire conditions are met, it means that although the vehicle currently reports a misfire fault, there is a certain possibility of false alarms, so it is necessary to further determine whether the engine cylinder is a real misfire or a false misfire caused by external interference. When judging, first determine the target engine cylinder based on the engine misfire signal. The target engine cylinder is the cylinder that needs to be further determined whether there is a real misfire. Controlling the target engine cylinder to stop injecting fuel is equivalent to creating a scene where the target engine cylinder really misfires, so as to observe the changes in the misfire signal of the target engine cylinder after stopping injecting fuel. In response to the engine misfire signal after stopping the injection of fuel and the engine misfire signal before stopping the injection of fuel satisfying the preset difference condition, it is indicated that the engine misfire signal after stopping the injection of fuel is less changed, indicating that the engine misfire signal of the target engine cylinder before stopping the injection of fuel is not caused by interference from external factors, and therefore the target engine cylinder is determined to be misfired. Through the method of stopping the injection of fuel in the target engine cylinder in the present application, it is possible to accurately determine whether the target engine cylinder is truly misfired or falsely misfired, thereby eliminating the problem of misjudgment of engine cylinder misfire. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram of a misfire signal when a single cylinder of an engine in an embodiment of the present application has continuous misfires; Figure 2 A schematic diagram of an engine misfire signal in the presence of external interference in an embodiment of the present application; Figure 3 A schematic flow chart of an engine misfire detection method according to an embodiment of the present application; Figure 4 This is a schematic diagram of the structure of an engine misfire detection device according to an embodiment of the present application; Figure 5 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0026] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] As described in the background art, when monitoring a misfire of a vehicle, if continuous misfire is determined, the misfire fault code of the corresponding engine cylinder needs to be reported so that the user can troubleshoot the cylinder with the misfire fault. Figure 1 The figure shows a misfire signal diagram when a single cylinder of the engine misfires continuously, where the horizontal axis x represents time in seconds, and the vertical axis y represents the engine speed change rate (engine misfire signal) in r / s. In one working cycle of the engine, each cylinder ignites and works in turn. If a cylinder misfires, the engine speed will jump greatly during the working period of the cylinder, resulting in a significant drop in engine speed and a large engine speed change rate. Figure 1 The engine corresponding to the misfire signal shown includes 4 cylinders. In each working cycle of the engine (such as Figure 1 The boxed area is the engine speed change rate within a working cycle). If the engine speed change rate corresponding to one cylinder is large and exceeds the preset misfire threshold, it is determined that the cylinder has a misfire phenomenon and is recorded in the misfire count statistics. If the misfire statistics exceed a certain value (that is, it exceeds the preset misfire threshold for multiple consecutive working cycles), it is determined that the cylinder has a continuous misfire phenomenon; the engine speed change rates corresponding to the remaining three cylinders are small and do not exceed the preset misfire threshold, so they are not recorded in the misfire count statistics. Figure 1 The misfire signal can determine that a misfire fault has occurred in the engine, and can determine the cylinder where the misfire fault has occurred (that is, the cylinder corresponding to the engine speed change rate that exceeds a preset misfire threshold during the engine working cycle).

[0028] However, in some hybrid vehicle architectures, a clutch is set between the engine and the motor. When the clutch is disconnected, the engine and the motor are disconnected; when the clutch is closed, the engine and the motor are connected, and the engine speed is synchronized with the motor speed, but the output torque of the engine may be different from the output torque of the motor, and the direction of the output torque of the engine may also be different from the direction of the output torque of the motor, such as the engine outputs positive torque and the motor outputs negative torque (generating torque). In this case, when the output torque of the motor changes, it will have a certain impact on the engine speed, causing the engine speed to fluctuate, and the misfire signal will fluctuate accordingly, thereby affecting the accuracy of the misfire signal. When the engine speed is high or the engine load is large, the change in the output torque of the motor has less interference with the engine speed, that is, less interference with the misfire signal, and the probability of misjudgment of the misfire fault is small. However, when the engine speed is low or the engine load is low, such as when the vehicle is in an idle condition or a low load condition, the engine load mainly comes from the generating torque output by the motor. Since the battery pack power of the vehicle is in a constantly changing state, the vehicle controller will control the motor to output different generating torques to ensure the balance of the battery pack power. At this time, the change in the motor's output torque has a greater impact on the engine speed. If one of the engine's cylinders has a misfire, the presence of motor interference will cause other normally operating cylinders to have a false misfire alarm, which brings certain difficulties to troubleshooting. Figure 2 FIG. 1 shows a schematic diagram of a misfire signal in the presence of external interference, wherein the horizontal axis x represents time in seconds, and the vertical axis y represents the rate of change of the engine speed in r / s. Figure 2 The engine corresponding to the misfire signal shown includes 4 cylinders. In each working cycle of the engine (such as Figure 2 The boxed area is the engine speed change rate within a working cycle), where the engine speed change rates corresponding to two cylinders are relatively large, exceeding the preset misfire threshold, and continuous misfire occurs; the engine speed change rates corresponding to the remaining two cylinders are relatively small, and do not exceed the preset misfire threshold. Among the two cylinders corresponding to the engine speed change rates that exceed the preset misfire threshold, the cylinder corresponding to the higher engine speed change rate has a true misfire fault, which results in a larger engine speed change rate; while the cylinder corresponding to the lower engine speed change rate has a false misfire fault due to external interference factors, resulting in the engine speed change rate exceeding the preset misfire threshold. This false misfire situation will interfere with the user's troubleshooting process. Therefore, when the vehicle is in a working condition with large external interference, it is necessary to further judge the engine misfire signal that exceeds the preset misfire threshold to determine whether it is a true misfire fault, thereby effectively reducing the probability of misjudgment of a misfire fault. The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0029] The embodiment of the present application proposes an engine misfire detection method, which can be applied to common controllers in vehicles such as an electronic control unit ECU (Electronic Control Unit), a hybrid control unit HCU (Hybrid Control Unit), a vehicle control unit VCU (Vehicle Control Unit) or an engine control module ECM (Engine Control Module), for reference. Figure 3 , the engine misfire detection method comprises the following steps: Step 102: Acquire vehicle operation data and engine misfire signal.

[0030] Specifically, vehicle operation data may include vehicle speed, engine operation data, etc. The vehicle operation data can provide a comprehensive understanding of the vehicle's operating status and the working conditions of the vehicle. The engine misfire signal is a signal obtained by monitoring the engine speed, which reflects the change in the engine speed change rate over time. When the engine speed change rate exceeds the preset misfire threshold, it means that the engine speed change rate is large, the engine speed changes more drastically, and the engine cylinder may have a misfire fault. By monitoring the engine misfire signal in real time, it can be preliminarily determined whether there is a suspected misfire fault in each cylinder of the engine.

[0031] Step 104: Determine whether the vehicle meets a preset predicted misfire condition based on the vehicle operation data and the engine misfire signal; if so, determine a target engine cylinder based on the engine misfire signal.

[0032] Specifically, it can be determined whether the vehicle meets the preset predicted misfire condition based on the vehicle operation data and the engine misfire signal, wherein the predicted misfire condition is used to characterize the conditions that the vehicle needs to meet under the vehicle operating conditions where misfire fault misjudgment may occur. That is, when the vehicle meets the preset predicted misfire condition, the vehicle will have a certain probability of misjudgment of misfire fault. At this time, it is necessary to further determine whether the engine cylinder is truly misfired. Since the engine includes multiple cylinders, it is also necessary to determine the target engine cylinder that needs to be further determined whether it is truly misfired among the multiple cylinders. When the engine misfire signal exceeds the preset misfire threshold, the cylinder corresponding to the engine misfire signal is the target engine cylinder. When the engine misfire signal does not exceed the preset misfire threshold, it is not necessary to further determine the cylinder, and the cylinder is not the target engine cylinder. Exemplarily, the engine misfire signal is the engine speed change rate. If the engine speed change rate exceeds the preset change rate threshold (preset misfire threshold), it is determined that the cylinder corresponding to the engine misfire signal is the target engine cylinder.

[0033] Step 106: Control the target engine cylinder to stop fuel injection, and in response to the engine misfire signal after the fuel injection is stopped and the engine misfire signal before the fuel injection is stopped meeting a preset difference condition, determine that the target engine cylinder is misfiring.

[0034] Specifically, when further judging the target engine cylinder, the method adopted is to control the target engine cylinder to stop injecting fuel, that is, to shut down the cylinder, which is equivalent to constructing a working condition of a true misfire in the engine cylinder. If there is a true misfire fault in the engine cylinder before the fuel injection is stopped, the engine misfire signal will not change significantly even after the fuel injection is stopped. However, if there is no true misfire fault in the engine cylinder before the fuel injection is stopped, the engine misfire signal will jump significantly after the fuel injection is stopped. Among them, satisfying the preset difference condition means that there is no obvious change in the engine misfire signal after the fuel injection is stopped. Therefore, in this embodiment, it is possible to determine whether the engine cylinder is truly misfired based on the engine misfire signal before and after the fuel injection is stopped, thereby achieving the purpose of accurately judging the engine misfire fault, avoiding the problem of false alarm of the misfire fault, and reducing the interference of users in troubleshooting the engine fault.

[0035] Based on the above steps 102 to 106, this embodiment provides an engine misfire detection method, including obtaining vehicle operation data and an engine misfire signal. The vehicle operation data can be used to understand the vehicle's operating status, and the engine misfire signal can be used to monitor whether the vehicle has a misfire fault prompt. Determine whether the vehicle meets the preset predicted misfire condition based on the vehicle operation data and the engine misfire signal. If the predicted misfire condition is met, it means that although the vehicle currently reports a misfire fault, there is a certain possibility of false alarms, so it is necessary to further determine whether the engine cylinder is a true misfire or a false misfire caused by external interference. When judging, first determine the target engine cylinder based on the engine misfire signal. The target engine cylinder is the cylinder whose misfire situation needs to be further determined. Controlling the target engine cylinder to stop injecting fuel is equivalent to creating a scene where the target engine cylinder really misfires, so as to observe the change of the misfire signal of the target engine cylinder after stopping injecting fuel. In response to the engine misfire signal after stopping the injection of fuel and the engine misfire signal before stopping the injection of fuel satisfying the preset difference condition, it is indicated that the engine misfire signal after stopping the injection of fuel is less changed, indicating that the engine misfire signal of the target engine cylinder before stopping the injection of fuel is not caused by interference from external factors, and therefore the target engine cylinder is determined to be misfired. Through the method of stopping the injection of fuel in the target engine cylinder in this embodiment, it is possible to accurately determine whether the target engine cylinder is truly misfired or false misfired, thereby eliminating the problem of misjudgment of engine cylinder misfire.

[0036] The following describes a situation where a vehicle meets the preset predicted misfire condition through a specific embodiment.

[0037] In some embodiments, the vehicle operation data includes engine water temperature, vehicle speed, engine operation time, engine speed, and engine load; and determining whether the vehicle meets a preset predicted misfire condition based on the vehicle operation data and the engine misfire signal includes: In response to the engine water temperature exceeding a preset water temperature threshold, the vehicle speed being less than a preset vehicle speed threshold, the engine running time exceeding a preset time, the engine speed being within a preset speed range, the engine load being within a preset load range, and the engine misfire signal continuously satisfying the misfire condition for more than a preset number of times, it is determined that the vehicle satisfies a preset predicted misfire condition.

[0038] Specifically, when the engine water temperature exceeds the preset water temperature threshold, for example, the preset water temperature threshold is -7°C, indicating that the engine temperature is not at a low temperature or does not belong to the low-temperature start condition. If the engine temperature is low or starts at low temperature, the engine's operating efficiency is usually low, and the speed fluctuates, which will have a certain impact on the misfire signal. Therefore, by limiting the engine water temperature by the preset water temperature threshold, the scenario of low engine operating efficiency can be avoided, eliminating the impact on the misfire signal.

[0039] When the engine running time exceeds the preset time, for example, the preset time is 5 seconds, it means that the engine is not in the state of just starting. If the engine has just started, the engine's operating efficiency is usually low and unstable, and the speed fluctuates, which will have a certain impact on the misfire signal. Therefore, by limiting the engine running time by the preset time, it can also avoid the scene of low engine operating efficiency and eliminate the impact on the misfire signal.

[0040] When the vehicle speed is less than the preset speed threshold, for example, the preset speed threshold is 60km / h, it means that the vehicle speed is slow, the power demand of the whole vehicle is small, the engine output power is small, and the engine's anti-interference ability is low. If there is interference with the motor output torque at this time, there is a possibility of misjudgment of the misfire signal.

[0041] When the engine speed is within the preset speed range, exemplarily, the preset speed range is [500r / min, 1450r / min], at this time, the engine speed is slow and the engine's anti-interference ability is weak. If there is interference from the motor output torque at this time, there is a possibility of misjudgment of the misfire signal.

[0042] When the engine load is within the preset load range, illustratively, the preset load range is [4%, 60%], at this time, the engine load is small and is in a low-load condition. The engine's anti-interference ability is weak. If there is interference with the motor output torque at this time, there is a possibility of misjudgment of the misfire signal.

[0043] When the engine water temperature, vehicle speed, engine running time, engine speed and engine load all meet the above conditions, there is a possibility of misjudgment of the misfire signal due to the change of the motor output torque. If the engine misfire signal continuously meets the misfire condition at this time, it is necessary to determine whether the misfire signal is caused by a true misfire fault, thereby eliminating the misjudgment of the misfire fault. Exemplarily, the engine misfire signal is the engine speed change rate. Meeting the misfire condition means that the engine speed change rate exceeds the preset speed change rate threshold, and it is necessary to further determine whether the engine cylinder is a true misfire.

[0044] Furthermore, after determining that the vehicle meets the preset predicted misfire conditions, the logic of active cylinder cutoff is activated to eliminate the misjudged misfire cylinder, and the misfire signal corresponding to the misfire fault prompt is judged to determine whether the engine cylinder is a true misfire or a false misfire.

[0045] Through the method of this embodiment, according to the working conditions where the vehicle may have a misjudgment of a misfire fault, the vehicle operation data is reasonably limited, and the predicted misfire conditions caused by the change in the motor output torque are formulated. By predicting the misfire conditions, the logic of actively activating the cylinder cut-off to eliminate the misjudged misfire cylinder is accurately and timely activated, and whether the misfire fault at this time is a true misfire fault is identified, thereby achieving the purpose of eliminating the misjudgment of the misfire fault, reducing the workload of technicians in troubleshooting, and improving user satisfaction.

[0046] When further judging the misfire fault, it is first necessary to determine the target engine cylinder that needs to be further judged from the multiple cylinders of the engine, thereby avoiding judging the misfire situation of each cylinder one by one and improving the judgment efficiency. The method for determining the target engine cylinder is explained below through a specific embodiment.

[0047] In some embodiments, determining a target engine cylinder according to the engine misfire signal includes: For the engine misfire signals corresponding to each cylinder in the engine working cycle, the cylinder corresponding to the engine misfire signal that meets the misfire condition is used as the target engine cylinder.

[0048] Specifically, the engine working cycle is the engine ignition cycle. During the engine ignition cycle, each cylinder of the engine is ignited and operated one by one according to the established ignition order. When a misfire occurs in one of the cylinders, the engine speed will drop significantly by a certain amount during the operation of the cylinder in each working cycle. The drop in engine speed will be reflected in the misfire signal. Therefore, the target engine cylinder that may have a fault and needs further verification can be determined based on the engine misfire signal. If the engine speed drops by a large amount, the rate of change of the engine speed is large. Correspondingly, if the misfire signal is characterized by the rate of change of the engine speed, the misfire signal value is large. According to the value of the misfire signal, a reasonable misfire condition can be formulated. When the misfire signal meets the misfire condition, it means that the value of the misfire signal is large. The cylinder corresponding to the misfire signal with a large misfire signal value is used as the target engine cylinder. In this way, the target engine cylinder can be accurately determined, and the cylinder that does not need further verification is excluded, which reduces the time required to verify the cylinder that may have a misfire fault and improves the verification efficiency.

[0049] The fire conditions are described in detail below through specific embodiments.

[0050] In some embodiments, the engine misfire signal includes an engine speed change rate; and the step of using a cylinder corresponding to the engine misfire signal that satisfies the misfire condition as the target engine cylinder includes: The cylinder whose engine speed change rate exceeds a preset change rate threshold is used as the target engine cylinder.

[0051] Specifically, the engine misfire signal represents the rate of change of the engine speed. When the rate of change of the engine speed exceeds the preset rate of change threshold, it indicates that the probability of a misfire fault in the current cylinder is relatively high, and further verification of the cylinder is required to determine whether the cylinder is a real misfire or a false misfire, and then the cylinder is determined as the target engine cylinder. The preset rate of change threshold is determined based on the misfire signal generated when the cylinder actually misfires. Exemplarily, the preset rate of change threshold is 80% of the maximum engine speed rate of change under a real misfire fault. When the engine speed rate of change exceeds the preset rate of change threshold, it indicates that the probability of a misfire fault is relatively high. Through the method of this embodiment, the misfire condition is reasonably formulated according to the preset misfire threshold, and the purpose of accurately determining the target engine cylinder is achieved.

[0052] After determining the target engine cylinder, it is necessary to further observe whether the misfire signal corresponding to the target engine cylinder is stable. If it is unstable, it will affect the accuracy of further verifying whether it is a real misfire. When the misfire signal of the target engine cylinder is stable, the target engine cylinder is controlled to stop injecting fuel. The following is explained by a specific embodiment.

[0053] In some embodiments, before controlling the target engine cylinder to stop fuel injection, the process includes: During a plurality of engine operating cycles, it is determined whether an engine misfire signal corresponding to a target engine cylinder satisfies a preset stability condition. If the preset stability condition is satisfied, the target engine cylinder is controlled to stop fuel injection.

[0054] Specifically, if the misfire signal of the target engine cylinder is unstable before stopping the injection, the variation range in adjacent working cycles is greatly different, which will affect the comparison and analysis process of the misfire signal after stopping the injection, resulting in inaccurate analysis and the possibility of misjudgment of misfire. Therefore, in order to further ensure the accuracy of the misfire judgment of the target engine cylinder, it is necessary to control the cylinder to stop injecting fuel after the misfire signal of the target engine cylinder is stable.

[0055] The specific method for determining whether the misfire signal of the target engine cylinder is stable is that if the engine misfire signal corresponding to the target engine cylinder meets the preset stability condition within multiple engine working cycles, it means that within multiple engine working cycles, the engine misfire signal has a small change amplitude and is in a relatively stable state, then the target engine cylinder can be controlled to stop injecting fuel. Within multiple engine working cycles, if the rate of change of the engine misfire signal is less than the preset rate of change threshold, it is determined that the preset stability condition is met. Exemplarily, the preset rate of change threshold can be 1%. When the engine misfire signal is the engine speed change rate, within each engine working cycle in multiple engine working cycles, the engine speed change rate and the engine speed change rate of the previous working cycle are calculated to have a change rate of less than 1%, and the engine speed change rate is maintained within a stable range, then it can be considered that the misfire signal of the target engine cylinder is in a stable state.

[0056] In another specific embodiment, if the difference between the maximum engine misfire signal (maximum engine speed change rate) and the minimum engine misfire signal (minimum engine speed change rate) is less than a preset stability threshold value during multiple engine operating cycles, it is determined that the preset stability condition is met. Exemplarily, the preset stability threshold value may be 5%. In this case, it can also be explained that during multiple engine operating cycles, the engine speed change rate changes little, and the engine speed change rate is maintained within a stable range. The method provided in this embodiment can accurately identify whether the engine misfire signal is stable, thereby ensuring the subsequent accurate judgment of whether there is a misfire fault in the target engine cylinder.

[0057] When controlling the target engine cylinder to stop fuel injection, if the engine cylinder is continuously controlled to stop fuel injection, it may cause engine shaking and affect the user experience. In order to avoid such problems, the present application provides a method for controlling the target engine cylinder to stop fuel injection, which is explained in the following embodiment.

[0058] In some embodiments, controlling the target engine cylinder to stop fuel injection includes: The target engine cylinder is controlled to stop fuel injection within a preset number of engine operating cycles.

[0059] Specifically, after the target engine cylinder is controlled to stop injecting fuel, if the target engine cylinder has a true misfire fault, the misfire signal jump amplitude after stopping the injection is small, that is, the misfire signal does not change much before and after stopping the injection. If the target engine cylinder has a false misfire fault caused by external interference, the misfire signal jump amplitude after stopping the injection is more obvious, that is, the misfire signal changes more before and after stopping the injection.

[0060] In order to accurately verify whether the target engine cylinder is a real misfire or a false misfire, it is necessary to stop the injection operation for many times to ensure the accuracy of the verification. At the same time, the number of times the injection operation is stopped should not be too many, that is, the number of working cycles of stopping the injection should not be too many, otherwise it may affect the power performance of the vehicle. Exemplarily, if the target engine cylinder has a false misfire caused by external interference, if the number of working cycles of stopping the injection is too many, the user will obviously feel that the vehicle's power performance has decreased, which brings a bad driving experience to the user. Therefore, it is necessary to determine a reasonable number of times to stop the injection. In this embodiment, the number of times the injection is stopped is a preset number. Exemplarily, the preset number can be 8 times. That is, after controlling the injection to stop for 8 working cycles, the injection operation of the target engine cylinder is resumed. The method of this embodiment can reasonably control the number of times the injection is stopped, avoid affecting the normal driving of the vehicle due to the verification of the target engine cylinder, and complete the verification of whether the target engine cylinder has a real misfire fault without affecting the user's driving experience.

[0061] When comparing the engine misfire signals before and after stopping the fuel injection, it is necessary to determine whether the engine misfire signals before and after stopping the fuel injection meet a preset difference condition, which is described below through a specific embodiment.

[0062] In some embodiments, the engine misfire signal includes an engine speed change rate; the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection meet a preset difference condition, including: In response to a difference between the engine speed change rate after stopping fuel injection and the engine speed change rate before stopping fuel injection being less than a preset difference threshold, it is determined that the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection meet a preset difference condition.

[0063] Specifically, the engine misfire signals before and after the fuel injection is stopped satisfy the preset difference condition, indicating that the difference in the engine speed change rate before and after the fuel injection is stopped is small, and the difference between the two engine misfire signals is less than the preset difference threshold, and the preset difference threshold may be 10% by way of example. In other words, after the fuel injection is stopped, there is no significant impact on the engine speed change rate, indicating that the target engine cylinder already has a misfire fault before the fuel injection is stopped, and therefore, after the fuel injection is stopped, the impact on the misfire signal is small.

[0064] On the contrary, the engine misfire signal before and after the fuel injection is stopped does not meet the preset difference condition, indicating that the difference in the engine speed change rate before and after the fuel injection is stopped is large, and the difference between the two engine misfire signals is greater than the preset difference threshold, and the preset difference threshold may be 10%. In other words, after the fuel injection is stopped, the engine speed change rate is greatly affected, indicating that the target engine cylinder does not have a misfire fault before the fuel injection is stopped, and it is a false misfire. Therefore, after the fuel injection is stopped, the impact on the misfire signal is greater.

[0065] Therefore, by setting a preset difference threshold, the change amplitude of the engine misfire signal before and after the injection is stopped can be accurately determined, ensuring the accuracy of determining whether there is a true misfire fault in the target engine cylinder and accurately identifying misfire situations.

[0066] In order to facilitate recording of the misfire fault condition of the target engine cylinder and accurate control of the vehicle controller, a misfire flag may be generated or removed to accurately feedback the misfire condition of the target engine cylinder, as described below through a specific embodiment.

[0067] In some embodiments, after determining the target engine cylinder according to the engine misfire signal, the method further includes: Generate a misfire flag corresponding to the target engine cylinder; After determining that the target engine cylinder misfires, the method further includes: Output the misfire flag corresponding to the target engine cylinder.

[0068] Specifically, the target engine cylinder is a cylinder that needs to be further verified whether there is a real misfire fault, that is, a cylinder with a real misfire probability. Therefore, after determining the target engine cylinder, a misfire flag corresponding to the target engine cylinder can be generated to mark the target engine cylinder. If it is verified by stopping the injection that the target engine cylinder does have a misfire fault, the misfire flag corresponding to the target engine cylinder is output to the corresponding control module or control unit, and recorded in the misfire count statistics. At the same time, the misfire alarm information can also be output to the corresponding terminal to remind the user to troubleshoot the engine misfire. By introducing the misfire flag, it is beneficial to count the number of misfires in the engine cylinder, and it is also beneficial to the precise control of the controller during the engine misfire detection process.

[0069] Accordingly, in some embodiments, the method further comprises: In response to the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection not satisfying a preset difference condition, it is determined that the target engine cylinder has not misfired, and the misfire flag corresponding to the target engine cylinder is removed.

[0070] Specifically, if the engine misfire signals before and after the cessation of fuel injection do not meet the preset difference conditions, it indicates that the target engine cylinder has a false misfire fault. If it is determined that the target engine cylinder has not misfired, the misfire flag generated previously can be eliminated to avoid counting false misfires into the misfire statistics, which would cause statistical errors.

[0071] Alternatively, when generating the misfire flag, the misfire flag is set to 1, and after determining that the target engine cylinder has not misfired, the misfire flag is set to 0. When counting misfire counts, only the number of misfire flags with the misfire flag being 1 is counted, and the number of misfire flags with the misfire flag being 0 is not counted, so that the number of true misfire faults can also be counted. The above 0 and 1 are only used as examples and have no limiting effect. 0 and 1 can be replaced according to actual needs, as long as the misfire flags corresponding to true misfires and false misfires can be distinguished.

[0072] When it is determined that the target engine cylinder has not misfired, by removing the misfire flag or setting the misfire flag to 0, it is possible to effectively avoid counting false misfire faults, which is beneficial to the accuracy of misfire fault statistics.

[0073] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the described method.

[0074] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0075] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides an engine misfire detection device.

[0076] refer to Figure 4 , the engine misfire detection device comprises: An acquisition module 402 is configured to acquire vehicle operation data and an engine misfire signal; A determination module 404 is configured to determine whether the vehicle meets a preset predicted misfire condition according to the vehicle operation data and the engine misfire signal, and if so, determine a target engine cylinder according to the engine misfire signal; The control module 406 is configured to control the target engine cylinder to stop fuel injection, and determine that the target engine cylinder misfires in response to the engine misfire signal after the fuel injection is stopped and the engine misfire signal before the fuel injection is stopped meeting a preset difference condition.

[0077] In some embodiments, the vehicle operation data includes engine water temperature, vehicle speed, engine running time, engine speed and engine load; the determination module 404 is configured to determine that the vehicle meets the preset predicted misfire condition in response to the engine water temperature exceeding a preset water temperature threshold, the vehicle speed being less than a preset vehicle speed threshold, the engine running time exceeding a preset time, the engine speed being within a preset speed range, the engine load being within a preset load range, and the engine misfire signal continuously meeting the misfire condition for more than a preset number of times.

[0078] In some embodiments, the determination module 404 is configured to use, for engine misfire signals corresponding to each cylinder in an engine working cycle, a cylinder corresponding to an engine misfire signal that meets a misfire condition as the target engine cylinder.

[0079] In some embodiments, the engine misfire signal includes an engine speed change rate; the determination module 404 is configured to use a cylinder whose engine speed change rate exceeds a preset change rate threshold as the target engine cylinder.

[0080] In some embodiments, before controlling the target engine cylinder to stop fuel injection, the determination module 404 is configured to determine whether the engine misfire signal corresponding to the target engine cylinder meets a preset stability condition within multiple engine operating cycles, and if the preset stability condition is met, control the target engine cylinder to stop fuel injection.

[0081] In some embodiments, the control module 406 is configured to control the target engine cylinder to stop injecting fuel within a preset number of engine working cycles.

[0082] In some embodiments, after determining the target engine cylinder according to the engine misfire signal, a flag management module is further included, configured to generate a misfire flag corresponding to the target engine cylinder; After determining that the target engine cylinder misfires, the flag management module is configured to output the misfire flag corresponding to the target engine cylinder.

[0083] In some embodiments, the flag management module is configured to determine that the target engine cylinder has not misfired in response to the engine misfire signal after the cessation of fuel injection and the engine misfire signal before the cessation of fuel injection satisfying a preset difference condition, and to eliminate the misfire flag corresponding to the target engine cylinder.

[0084] For the convenience of description, the above device is described in terms of functions divided into various modules. Of course, when implementing the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0085] The device of the above embodiment is used to implement the corresponding engine misfire detection method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0086] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the engine misfire detection method described in any of the above embodiments is implemented.

[0087] Figure 5 A more specific schematic diagram of the hardware structure of an electronic device provided in this embodiment is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0088] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0089] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program codes are stored in the memory 1020 and are called and executed by the processor 1010.

[0090] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0091] The communication interface 1040 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0092] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010 , the memory 1020 , the input / output interface 1030 , and the communication interface 1040 ).

[0093] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0094] The electronic device of the above embodiment is used to implement the corresponding engine misfire detection method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0095] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the engine misfire detection method as described in any of the above embodiments.

[0096] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, 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, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0097] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the engine misfire detection method as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0098] Based on the same concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a computer program product, including computer program instructions. When the computer program instructions are run on a computer, the computer executes the method described in any of the above embodiments, which has the beneficial effects of the corresponding method embodiments and will not be repeated here.

[0099] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0100] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power / ground connections to the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device may be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application are to be implemented (that is, these details should be fully within the scope of understanding of those skilled in the art). Where specific details (e.g., circuits) are set forth to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or with changes in these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0101] Although the present application has been described in conjunction with specific embodiments of the present application, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the discussed embodiments.

[0102] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the present application.

Claims

1. An engine misfire detection method, characterized in that: include: Obtain vehicle operation data and engine misfire signals; determining whether the vehicle satisfies a preset predicted misfire condition according to the vehicle operation data and the engine misfire signal, and if so, determining a target engine cylinder according to the engine misfire signal; The target engine cylinder is controlled to stop fuel injection, and in response to an engine misfire signal after the fuel injection is stopped and an engine misfire signal before the fuel injection is stopped satisfying a preset difference condition, it is determined that the target engine cylinder is misfiring.

2. The method according to claim 1, characterized in that The vehicle operation data includes engine water temperature, vehicle speed, engine operation time, engine speed, and engine load; the determining whether the vehicle meets the preset predicted misfire condition according to the vehicle operation data and the engine misfire signal includes: In response to the engine water temperature exceeding a preset water temperature threshold, the vehicle speed being less than a preset vehicle speed threshold, the engine running time exceeding a preset time, the engine speed being within a preset speed range, the engine load being within a preset load range, and the engine misfire signal continuously satisfying the misfire condition for more than a preset number of times, it is determined that the vehicle satisfies a preset predicted misfire condition.

3. The method according to claim 1, characterized in that Determining a target engine cylinder according to the engine misfire signal includes: For the engine misfire signals corresponding to each cylinder in the engine working cycle, the cylinder corresponding to the engine misfire signal that meets the misfire condition is used as the target engine cylinder.

4. The method according to claim 3, characterized in that The engine misfire signal includes an engine speed change rate; the cylinder corresponding to the engine misfire signal that meets the misfire condition is used as the target engine cylinder, including: The cylinder whose engine speed change rate exceeds a preset change rate threshold is used as the target engine cylinder.

5. The method according to claim 1, characterized in that Before controlling the target engine cylinder to stop fuel injection, the method includes: During a plurality of engine operating cycles, it is determined whether an engine misfire signal corresponding to a target engine cylinder satisfies a preset stability condition. If the preset stability condition is satisfied, the target engine cylinder is controlled to stop fuel injection.

6. The method according to claim 1, characterized in that Controlling the target engine cylinder to stop fuel injection includes: The target engine cylinder is controlled to stop fuel injection within a preset number of engine operating cycles.

7. The method according to claim 1, characterized in that The engine misfire signal includes the engine speed change rate; the engine misfire signal after stopping the injection and the engine misfire signal before stopping the injection meet the preset difference condition, including: In response to a difference between the engine speed change rate after stopping fuel injection and the engine speed change rate before stopping fuel injection being less than a preset difference threshold, it is determined that the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection meet a preset difference condition.

8. The method according to claim 1, characterized in that After determining the target engine cylinder according to the engine misfire signal, the method further includes: Generate a misfire flag corresponding to the target engine cylinder; After determining that the target engine cylinder misfires, the method further includes: Output the misfire flag corresponding to the target engine cylinder.

9. The method according to claim 8, characterized in that The method further comprises: In response to the engine misfire signal after stopping fuel injection and the engine misfire signal before stopping fuel injection not satisfying a preset difference condition, it is determined that the target engine cylinder has not misfired, and the misfire flag corresponding to the target engine cylinder is removed.

10. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the method according to any one of claims 1 to 9.

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