Engine misfire detection method and vehicle

Abstract

The present application provides an engine misfire detection method and vehicle, the method comprising obtaining vehicle operating data and an engine misfire signal. Based on the vehicle operating data and the engine misfire signal, it is determined whether the vehicle meets a preset predicted misfire condition. If the predicted misfire condition is met, a target engine cylinder is determined based on the engine misfire signal. Fuel injection is controlled to stop the target engine cylinder, and in response to the engine misfire signal after the cessation of fuel injection and the engine misfire signal before the cessation of fuel injection meeting a preset difference condition, the target engine cylinder is determined to be misfired. By using the method of stopping fuel injection in the target engine cylinder of 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.

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 misfires can cause a decrease in engine operating stability, power, and economy. Therefore, vehicles monitor for engine misfire signals and, when the number of detected misfires reaches a certain threshold, generate a misfire fault code, prompting the user to troubleshoot the engine fault. However, hybrid vehicles can experience false misfire alarms under certain operating conditions, making misfire detection difficult. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide an engine misfire detection method and 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:

[0005] Obtain vehicle operation data and engine misfire signals;

[0006] determining whether the vehicle satisfies a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal, and if so, determining a target engine cylinder based on the engine misfire signal;

[0007] 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 meeting a preset difference condition, it is determined that the target engine cylinder is misfired.

[0008] By using the method of stopping fuel injection in 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.

[0009] Optionally, the vehicle operating data includes engine water temperature, vehicle speed, engine operating time, engine speed, and engine load; and determining whether the vehicle meets a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal includes:

[0010] 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 operating 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 exceeding a preset number of times, it is determined that the vehicle satisfies a preset predicted misfire condition.

[0011] The method described in the above embodiment rationally limits vehicle operating data based on operating conditions where misfire faults may be misdiagnosed, establishing predicted misfire conditions. By predicting these conditions, the active cylinder deactivation logic is accurately and timely activated to eliminate misdiagnosed misfire cylinders, identifying whether the misfire fault is a true misfire. This eliminates misdiagnoses, avoids increased troubleshooting workload for technicians due to false engine misfire alarms, and improves customer satisfaction.

[0012] Optionally, determining a target engine cylinder according to the engine misfire signal includes:

[0013] For the engine misfire signals corresponding to the various cylinders 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.

[0014] This embodiment can accurately determine the target engine cylinder, eliminate cylinders that do not require further verification, reduce the time required to verify cylinders that may have misfire faults, and improve verification efficiency.

[0015] 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:

[0016] The cylinder whose engine speed change rate exceeds a preset change rate threshold is used as the target engine cylinder.

[0017] 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.

[0018] Optionally, before controlling the target engine cylinder to stop fuel injection, the method further includes:

[0019] 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.

[0020] The method provided in this embodiment can accurately identify whether the engine misfire signal is stable, ensuring subsequent accurate judgment of whether a misfire fault occurs in the target engine cylinder.

[0021] Optionally, controlling the target engine cylinder to stop fuel injection includes:

[0022] The target engine cylinder is controlled to stop injecting fuel within a preset number of engine operating cycles.

[0023] 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.

[0024] 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:

[0025] In response to a difference between the engine speed change rate after fuel injection is stopped and the engine speed change rate before fuel injection is stopped being less than a preset difference threshold, it is determined that the engine misfire signal after fuel injection is stopped and the engine misfire signal before fuel injection is stopped meet a preset difference condition.

[0026] This embodiment can accurately determine the change amplitude of the engine misfire signal before and after stopping fuel injection by setting a preset difference threshold, ensuring the accuracy of determining whether there is a true misfire fault in the target engine cylinder and accurately identifying misfire cases.

[0027] Optionally, after determining the target engine cylinder according to the engine misfire signal, the method further includes:

[0028] generating a misfire flag corresponding to the target engine cylinder;

[0029] After determining that the target engine cylinder misfires, the method further includes:

[0030] Output the misfire flag corresponding to the target engine cylinder.

[0031] This embodiment introduces a misfire flag, which is beneficial for counting the number of misfires in the engine cylinders and is also beneficial for accurate control of the controller during the engine misfire detection process.

[0032] Optionally, the method further includes:

[0033] 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.

[0034] This embodiment can effectively avoid counting false misfire faults by eliminating the misfire flag when determining that the target engine cylinder is not misfiring, thereby improving the accuracy of misfire fault statistics.

[0035] Based on the same inventive concept, the present application also provides a vehicle, comprising:

[0036] a memory for storing executable program code;

[0037] A processor is used to call and run the executable program code from the memory, so that the vehicle executes the method as described in the first aspect.

[0038] As can be seen from the foregoing, the engine misfire detection method and vehicle provided in this application include acquiring vehicle operating data and an engine misfire signal. The vehicle operating 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 experienced a misfire fault. Based on the vehicle operating data and the engine misfire signal, a determination is made as to whether the vehicle meets preset predicted misfire conditions. If the predicted misfire conditions are met, this indicates that although the vehicle has currently reported a misfire fault, there is a certain possibility of a false alarm, and further determination is required as to whether the engine cylinder misfires or is a false misfire caused by external interference. During this determination, the target engine cylinder is first identified based on the engine misfire signal. The target engine cylinder is the cylinder for which further determination of whether a true misfire exists. Fuel injection is then controlled to cease in the target engine cylinder, effectively creating a true misfire scenario in the target engine cylinder, so that the changes in the misfire signal in the target engine cylinder after fuel injection is ceased are observed. In response to the engine misfire signal after fuel injection cessation and the engine misfire signal before fuel injection cessation satisfying a preset difference condition, it indicates that the engine misfire signal after fuel injection cessation has a small change, indicating that the engine misfire signal of the target engine cylinder before fuel injection cessation was not caused by interference from external factors, and therefore, the target engine cylinder is determined to be misfire. Through the method of cessation of fuel injection in the target engine cylinder of the present application, it is possible to accurately determine whether the target engine cylinder is misfired or false, thereby eliminating the problem of false misfire in the engine cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 This is a schematic diagram of a misfire signal when a single cylinder of an engine according to an embodiment of the present application exhibits continuous misfires;

[0041] Figure 2 This is a schematic diagram of an engine misfire signal in the presence of external interference according to an embodiment of the present application;

[0042] Figure 3 Schematic diagram of the flow of the engine misfire detection method according to an embodiment of the present application;

[0043] Figure 4This is a schematic structural diagram of an engine misfire detection device according to an embodiment of the present application;

[0044] 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

[0045] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0046] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before 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 may 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.

[0047] As described in the background art, when monitoring a vehicle misfire, 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 This diagram shows a misfire signal when a single engine cylinder experiences continuous misfires. The x-axis represents time in seconds, and the y-axis represents the rate of change of engine speed (the misfire signal) in revolutions per second. During an engine operating cycle, each cylinder fires in turn. If a cylinder misfires, the engine speed will experience a significant jump during that cylinder's operating period, resulting in a significant drop in engine speed and a large rate of change. Figure 1 The engine corresponding to the misfire signal shown includes 4 cylinders. In each working cycle of the engine (such as Figure 1The 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 misfired and is recorded in the misfire count statistics. If the number of misfire statistics exceeds a certain value (that is, it exceeds the preset misfire threshold for multiple consecutive working cycles), it is determined that the cylinder has continuously misfired. 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 the engine has a misfire fault, and can determine the cylinder where the misfire fault occurs (that is, the cylinder corresponding to the engine speed change rate that exceeds the preset misfire threshold during the engine working cycle).

[0048] However, in some hybrid vehicle architectures, a clutch is installed between the engine and motor. When the clutch is disengaged, the engine and motor are disconnected; when the clutch is engaged, the engine and motor are connected, and the engine speed is synchronized with the motor speed. However, the engine output torque may differ from the motor output torque, and the direction of the engine output torque may also differ. For example, the engine outputs positive torque while the motor outputs negative torque (generator torque). In this case, when the motor output torque changes, it will have a certain impact on the engine speed, causing engine speed fluctuations and consequently, fluctuations in the misfire signal, which in turn affects the accuracy of the misfire signal. At high engine speeds or high engine loads, changes in motor output torque have less interference with engine speed, and thus less interference with the misfire signal, reducing the probability of misfire fault misdiagnosis. However, at low engine speeds or low engine loads, such as when the vehicle is idling or operating at low load, the engine load is primarily derived from the generator torque output by the motor. Since the battery pack charge is constantly changing, the vehicle controller controls the motor output to output different generator torques to ensure battery pack charge balance. At this time, the change in the motor's output torque has a greater impact on the engine speed. If a misfire occurs in one of the engine's cylinders, the presence of motor interference will cause false misfire alarms in other normally operating cylinders, making troubleshooting difficult. Figure 2 The figure 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 2The boxed area represents the engine speed change rate within a single operating cycle. Two cylinders have relatively large engine speed change rates, exceeding the preset misfire threshold and resulting in continuous misfires. The remaining two cylinders have relatively small engine speed change rates, not exceeding the preset misfire threshold. Of the two cylinders with engine speed change rates exceeding the preset misfire threshold, the cylinder with the higher engine speed change rate has a true misfire fault, resulting in a larger engine speed change rate. The cylinder with the lower engine speed change rate has a false misfire fault due to external interference, causing the engine speed change rate to exceed the preset misfire threshold. This false misfire situation can interfere with the user's troubleshooting process. Therefore, when the vehicle is operating in conditions with significant external interference, further evaluation of engine misfire signals exceeding the preset misfire threshold is necessary to determine whether they represent a true misfire fault, thereby effectively reducing the probability of misdiagnosing a misfire fault.

[0049] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0050] The embodiment of the present application proposes an engine misfire detection method, which can be applied to common controllers in vehicles such as the electronic control unit ECU (Electronic Control Unit), hybrid control unit HCU (Hybrid Control Unit), vehicle control unit VCU (Vehicle Control Unit) or engine control module ECM (Engine Control Module). Figure 3 , the engine misfire detection method comprises the following steps:

[0051] Step 102: Acquire vehicle operation data and engine misfire signal.

[0052] Specifically, vehicle operating data may include vehicle speed, engine operating data, and the like. Vehicle operating data provides a comprehensive understanding of the vehicle's operating status and operating conditions. The engine misfire signal is a signal obtained by monitoring the engine speed, reflecting the rate of change of the engine speed over time. When the engine speed change rate exceeds a preset misfire threshold, it indicates a high rate of change in engine speed, a more drastic change in engine speed, and a possible misfire in an engine cylinder. By monitoring the engine misfire signal in real time, it is possible to preliminarily determine whether a suspected misfire has occurred in each cylinder of the engine.

[0053] Step 104 : Determine whether the vehicle meets a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal; if so, determine a target engine cylinder based on the engine misfire signal.

[0054] Specifically, based on vehicle operating data and an engine misfire signal, it can be determined whether the vehicle meets preset predicted misfire conditions. Predicted misfire conditions characterize the conditions that must be met under vehicle operating conditions where a misfire fault misdiagnosis may occur. Specifically, when the vehicle meets the preset predicted misfire conditions, there is a certain probability of misdiagnosis of a misfire fault. In this case, further determination is required as to whether the engine cylinder is truly misfired. Because an engine includes multiple cylinders, it is also necessary to identify a target cylinder among the multiple cylinders for further determination of true misfire. When the engine misfire signal exceeds a preset misfire threshold, the cylinder corresponding to the engine misfire signal is designated as the target cylinder. When the engine misfire signal does not exceed the preset misfire threshold, no further determination is required for the cylinder, indicating that the cylinder is not the target cylinder. Exemplarily, the engine misfire signal is the engine speed change rate. If the engine speed change rate exceeds a preset change rate threshold (preset misfire threshold), the cylinder corresponding to the engine misfire signal is determined to be the target cylinder.

[0055] Step 106 : Controlling the target engine cylinder to stop fuel injection, and determining that the target engine cylinder is misfired 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.

[0056] Specifically, when further determining the target engine cylinder, the method employed is to control the target engine cylinder to stop fuel injection, i.e., to shut off the cylinder. This is equivalent to creating a true engine cylinder misfire condition. If a true engine cylinder misfire fault existed before fuel injection was stopped, the engine misfire signal would not show a noticeable change even after fuel injection was stopped. However, if a true engine cylinder misfire fault did not exist before fuel injection was stopped, the engine misfire signal would show a noticeable jump after fuel injection was stopped. Satisfying the preset difference condition means that the engine misfire signal does not show a noticeable change after fuel injection is stopped. Therefore, in this embodiment, whether an engine cylinder misfires is true can be determined based on the engine misfire signal before and after fuel injection is stopped, achieving the purpose of accurately determining engine misfire faults, avoiding false misfire alarms, and reducing user interference with engine troubleshooting.

[0057] Based on steps 102 to 106 above, this embodiment provides an engine misfire detection method, which includes acquiring vehicle operating data and an engine misfire signal. The vehicle operating 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 experienced a misfire fault. Based on the vehicle operating data and the engine misfire signal, a determination is made as to whether the vehicle meets preset predicted misfire conditions. If the predicted misfire conditions are met, this indicates that while the vehicle has currently reported a misfire fault, there is a certain possibility of a false alarm, and further determination is required as to whether the engine cylinder misfires truly or is a false alarm caused by external interference. During this determination, the target engine cylinder is first identified based on the engine misfire signal. The target engine cylinder is the cylinder whose misfire condition requires further assessment. Fuel injection is then controlled to cease in the target engine cylinder, effectively creating a scenario in which the target engine cylinder misfires. The changes in the misfire signal in the target engine cylinder after fuel injection is ceased are then observed. In response to the engine misfire signal after fuel injection cessation and the engine misfire signal before fuel injection cessation satisfying a preset difference condition, it indicates that the engine misfire signal after fuel injection cessation has changed little, indicating that the engine misfire signal of the target engine cylinder before fuel injection cessation was not caused by external interference, and therefore, misfire is determined in the target engine cylinder. The method of cessating fuel injection in the target engine cylinder in this embodiment can accurately determine whether the target engine cylinder is misfiring or false misfiring, thereby eliminating the problem of false misfire in the target engine cylinder.

[0058] The following describes a case where a vehicle meets the preset predicted misfire conditions through a specific embodiment.

[0059] In some embodiments, the vehicle operating data includes engine water temperature, vehicle speed, engine operating time, engine speed, and engine load; and determining whether the vehicle meets a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal includes:

[0060] 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 operating 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 exceeding a preset number of times, it is determined that the vehicle satisfies a preset predicted misfire condition.

[0061] Specifically, when the engine water temperature exceeds a preset water temperature threshold (e.g., -7°C), it indicates that the engine temperature is not at a low temperature or is not in a low-temperature start condition. Low engine temperatures or low-temperature starts typically result in lower engine efficiency and speed fluctuations, which can affect the misfire signal. Therefore, limiting the engine water temperature by setting a preset water temperature threshold can avoid scenarios where engine efficiency is low and eliminate the impact on the misfire signal.

[0062] If the engine runs for longer than a preset duration (e.g., 5 seconds), it indicates the engine has not just started. When the engine is just started, its efficiency is typically low and unstable, with speed fluctuations, which can affect the misfire signal. Therefore, limiting the engine run time by a preset duration can also prevent low engine efficiency and eliminate the impact on the misfire signal.

[0063] 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 power output of the engine 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.

[0064] When the engine speed is within the preset speed range, for example, 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.

[0065] When the engine load is within the preset load range, for example, the preset load range is [4%, 60%], the engine load is small and is in a low-load operating condition. 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.

[0066] If the engine water temperature, vehicle speed, engine runtime, engine speed, and engine load all meet the aforementioned conditions, there is a possibility of misjudgment of a misfire signal due to changes in motor output torque. If the engine misfire signal continuously meets the misfire conditions, it is necessary to determine whether the misfire signal is caused by a true misfire fault, thereby eliminating misjudgments of misfire faults. For example, if the engine misfire signal is the engine speed change rate, meeting the misfire condition indicates that the engine speed change rate exceeds a preset speed change rate threshold, and further determination is required to determine whether the engine cylinder is misfiring.

[0067] 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 at this time is a true misfire or a false misfire.

[0068] The method of this embodiment rationally limits vehicle operating data based on operating conditions where misfire faults may be misdiagnosed, and establishes predicted misfire conditions caused by changes in motor output torque. By predicting these misfire conditions, the active cylinder deactivation logic is accurately and promptly activated to eliminate misdiagnosed misfire cylinders, identifying whether the misfire fault is a true one. This eliminates misdiagnoses, reduces technician troubleshooting workload, and improves customer satisfaction.

[0069] When further judging a misfire fault, it is first necessary to determine the target engine cylinder that needs further judgment from the multiple cylinders of the engine. This can avoid judging the misfire situation of each cylinder one by one and improve the judgment efficiency. The following describes the method for determining the target engine cylinder through a specific embodiment.

[0070] In some embodiments, determining a target engine cylinder based on the engine misfire signal includes:

[0071] For the engine misfire signals corresponding to the various cylinders 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.

[0072] Specifically, an engine operating cycle is an engine ignition cycle. During this cycle, each cylinder of the engine ignites and operates one by one according to a predetermined ignition sequence. If a cylinder misfires, the engine speed will drop significantly during each operating cycle. This drop in engine speed will be reflected in the misfire signal. Therefore, the misfire signal can be used to identify target cylinders that may be faulty and require further verification. If the engine speed drop is significant, the rate of change is high. Accordingly, if the misfire signal is characterized by the rate of change, the misfire signal value will be high. Based on the misfire signal value, appropriate misfire conditions can be established. When the misfire signal meets the misfire conditions, indicating a high misfire signal value, the cylinder corresponding to the high misfire signal value is selected as the target cylinder. This allows accurate identification of the target cylinder, eliminating cylinders that do not require further verification, reducing the time required to verify cylinders that may have misfire problems, and improving verification efficiency.

[0073] The fire conditions are described in detail below through specific embodiments.

[0074] 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:

[0075] The cylinder whose engine speed change rate exceeds a preset change rate threshold is used as the target engine cylinder.

[0076] Specifically, the engine misfire signal represents the rate of change of the engine speed. When the engine speed rate of change exceeds a preset rate of change threshold, it indicates a high probability of a misfire in the current cylinder. Further verification of the cylinder is required to determine whether it is a true misfire or a false misfire. This cylinder is then identified as the target engine cylinder. The preset rate of change threshold is determined based on the misfire signal generated when the cylinder misfires. For example, the preset rate of change threshold is 80% of the maximum engine speed rate of change under a true misfire condition. When the engine speed rate of change exceeds the preset rate of change threshold, it indicates a high probability of a misfire. Through the method of this embodiment, misfire conditions are rationally established based on the preset misfire threshold, achieving the goal of accurately identifying the target engine cylinder.

[0077] 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, the accuracy of further verification of whether the misfire is true will be affected. When the misfire signal of the target engine cylinder stabilizes, the target engine cylinder is controlled to stop injecting fuel. The following is a specific example to illustrate this.

[0078] In some embodiments, before controlling the target engine cylinder to stop fuel injection, the method includes:

[0079] 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.

[0080] Specifically, if the target engine cylinder's misfire signal is unstable before fuel injection is stopped, the fluctuation range varies significantly between adjacent operating cycles. This will affect the comparison and analysis process with the misfire signal after fuel injection is stopped, resulting in inaccurate analysis and the possibility of misfire misjudgment. Therefore, to further ensure the accuracy of misfire judgment in the target engine cylinder, it is necessary to control the cylinder to stop fuel injection after the misfire signal in the target engine cylinder stabilizes.

[0081] The specific method for determining whether the misfire signal of the target engine cylinder is stable is as follows: if the engine misfire signal corresponding to the target engine cylinder satisfies a preset stability condition over multiple engine operating cycles, indicating that the engine misfire signal has a small change amplitude and is in a relatively stable state over the multiple engine operating cycles, the target engine cylinder can be controlled to stop injecting fuel. If the rate of change of the engine misfire signal is less than a preset rate of change threshold over the multiple engine operating cycles, 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 of the multiple engine operating cycles, the engine speed change rate and the engine speed change rate calculated from the previous operating cycle are both less than 1%, and the engine speed change rate remains within a stable range, then the misfire signal of the target engine cylinder can be considered to be in a stable state.

[0082] 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) over multiple engine operating cycles is less than a preset stability threshold, then the preset stability condition is determined to be met. For example, the preset stability threshold may be 5%. In this case, it can also be indicated that the engine speed change rate has changed little over the multiple engine operating cycles, remaining within a stable range. The method provided in this embodiment can accurately identify whether the engine misfire signal is stable, ensuring subsequent accurate determination of whether a misfire fault exists in the target engine cylinder.

[0083] 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 vibration and affect the user experience. In order to avoid this problem, the present application provides a method for controlling the target engine cylinder to stop fuel injection, which is explained in the following embodiment.

[0084] In some embodiments, controlling the target engine cylinder to stop fuel injection includes:

[0085] The target engine cylinder is controlled to stop injecting fuel within a preset number of engine operating cycles.

[0086] Specifically, after stopping fuel injection in a target engine cylinder, if a true misfire occurs in the target engine cylinder, the misfire signal will have a smaller jump amplitude after stopping fuel injection, meaning the misfire signal will not change much before and after stopping fuel injection. If a false misfire occurs in the target engine cylinder due to external interference, the misfire signal will have a larger jump amplitude after stopping fuel injection, meaning the misfire signal will change significantly before and after stopping fuel injection.

[0087] To accurately verify whether a target engine cylinder misfires or false misfires, multiple fuel injection cessation operations are required to ensure verification accuracy. Furthermore, the number of fuel injection cessation operations should be limited, meaning the number of fuel injection cessation cycles should be limited, as this can affect the vehicle's power performance. For example, if a target engine cylinder experiences a false misfire caused by external interference, excessive fuel injection cessation cycles can significantly degrade the vehicle's power performance, resulting in a poor driving experience. Therefore, it is necessary to determine a reasonable number of fuel injection cessation operations. In this embodiment, the number of fuel injection cessation operations is a preset number, for example, eight. Specifically, after eight fuel injection cessation cycles, fuel injection is resumed in the target engine cylinder. The method of this embodiment allows for reasonable control of the number of fuel injection cessation operations, preventing the verification of the target engine cylinder from disrupting normal vehicle operation. This allows for verification of whether a target engine cylinder misfires or not without impacting the user's driving experience.

[0088] When comparing the engine misfire signals before and after stopping fuel injection, it is necessary to determine whether the engine misfire signals before and after stopping fuel injection meet a preset difference condition, which is described below through a specific embodiment.

[0089] 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:

[0090] In response to a difference between the engine speed change rate after fuel injection is stopped and the engine speed change rate before fuel injection is stopped being less than a preset difference threshold, it is determined that the engine misfire signal after fuel injection is stopped and the engine misfire signal before fuel injection is stopped meet a preset difference condition.

[0091] Specifically, the engine misfire signals before and after the cessation of fuel injection meet a preset difference condition, indicating that the difference in the engine speed change rate before and after the cessation of fuel injection is small, and the difference between the two engine misfire signals is less than a preset difference threshold. For example, the preset difference threshold may be 10%. In other words, cessation of fuel injection does not significantly affect the engine speed change rate, indicating that the target engine cylinder already had a misfire fault before the cessation of fuel injection. Therefore, cessation of fuel injection has a minimal impact on the misfire signal.

[0092] Conversely, if the engine misfire signals before and after the cessation of fuel injection do not meet the preset difference condition, this indicates a significant difference in the engine speed change rate before and after the cessation of fuel injection. The difference between the two engine misfire signals is greater than a preset difference threshold, which may be, for example, 10%. In other words, the cessation of fuel injection significantly impacts the engine speed change rate, indicating that the target engine cylinder did not experience a misfire fault before the cessation of fuel injection, resulting in a false misfire. Therefore, the cessation of fuel injection significantly impacts the misfire signal.

[0093] Therefore, by setting a preset difference threshold, the change amplitude of the engine misfire signal before and after the cessation of fuel injection 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 cases.

[0094] 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 can be generated or deleted to accurately feedback the misfire condition of the target engine cylinder, which is explained below through specific embodiments.

[0095] In some embodiments, after determining the target engine cylinder according to the engine misfire signal, the method further includes:

[0096] generating a misfire flag corresponding to the target engine cylinder;

[0097] After determining that the target engine cylinder misfires, the method further includes:

[0098] Output the misfire flag corresponding to the target engine cylinder.

[0099] Specifically, the target engine cylinder is the cylinder that needs to be further verified to see if there is a true misfire fault, that is, the cylinder that has a true 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 fuel 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 fault. By introducing the misfire flag, it is beneficial to count the number of misfires in the engine cylinder and also to accurately control the controller during the engine misfire detection process.

[0100] Accordingly, in some embodiments, the method further includes:

[0101] 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.

[0102] 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 previously generated misfire flag can be eliminated to avoid counting the false misfire in the misfire statistics and causing statistical errors.

[0103] Alternatively, when generating the misfire flag, the misfire flag is set to 1. Once it is determined that the target engine cylinder is not misfiring, the misfire flag is set to 0. When counting misfires, only those misfire flags set to 1 are counted, ignoring those set to 0. This also allows for the counting of true misfire failures. The values 0 and 1 are provided for illustrative purposes only and are not limiting. These values can be replaced with 0 based on actual needs, as long as the misfire flags corresponding to true and false misfires can be distinguished.

[0104] When it is determined that the target engine cylinder is not misfiring, 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.

[0105] 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 in a distributed scenario and performed by multiple devices working together. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the method.

[0106] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0107] 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.

[0108] refer to Figure 4 , the engine misfire detection device comprises:

[0109] An acquisition module 402 is configured to acquire vehicle operation data and an engine misfire signal;

[0110] a determination module 404 configured to determine whether the vehicle satisfies a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal, and if so, determine a target engine cylinder based on the engine misfire signal;

[0111] The control module 406 is configured to control the target engine cylinder to stop fuel injection, and determine that the target engine cylinder is misfired 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.

[0112] In some embodiments, the vehicle operating 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 meeting the misfire condition continuously for more than a preset number of times.

[0113] In some embodiments, the determination module 404 is configured to, for engine misfire signals corresponding to various cylinders within an engine operating cycle, select the cylinder corresponding to the engine misfire signal that meets the misfire condition as the target engine cylinder.

[0114] In some embodiments, the engine misfire signal includes an engine speed change rate; the determination module 404 is configured to select a cylinder whose engine speed change rate exceeds a preset change rate threshold as the target engine cylinder.

[0115] 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.

[0116] In some embodiments, the control module 406 is configured to control the target engine cylinder to stop injecting fuel within a predetermined number of engine operating cycles.

[0117] In some embodiments, after determining the target engine cylinder according to the engine misfire signal, the system further includes a flag management module configured to generate a misfire flag corresponding to the target engine cylinder;

[0118] After determining that the target engine cylinder is misfired, the flag management module is configured to output a misfire flag corresponding to the target engine cylinder.

[0119] In some embodiments, the flag management module is configured to determine that the target engine cylinder is not misfired in response to the engine misfire signal after 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, and to eliminate the misfire flag corresponding to the target engine cylinder.

[0120] For the convenience of description, the above devices are described as being divided into various modules according to their functions. Of course, when implementing this application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0121] The apparatus 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.

[0122] 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.

[0123] Figure 5 A more specific hardware structure diagram of an electronic device provided in this embodiment is shown. 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 communicatively connected to each other within the device via the bus 1050.

[0124] The processor 1010 can be implemented using 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.

[0125] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage devices, dynamic storage devices, etc. The memory 1020 can store an operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0126] The input / output interface 1030 is used to connect to input / output modules to enable information input and output. The input / output modules can be configured as components within the device (not shown) or externally connected to the device to provide corresponding functions. Input devices may include a keyboard, mouse, touch screen, microphone, and various sensors. Output devices may include a display, speaker, vibrator, indicator light, and the like.

[0127] The communication interface 1040 is used to connect to a communication module (not shown) to enable communication between the device and other devices. The communication module can communicate via wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, Wi-Fi, Bluetooth, etc.).

[0128] The bus 1050 comprises a pathway for transmitting information between various components of the device, such as the processor 1010 , the memory 1020 , the input / output interface 1030 , and the communication interface 1040 .

[0129] 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 a specific implementation, the device may also include other components necessary for normal operation. In addition, it will be understood by those skilled in the art that the above device may only include the components necessary to implement the embodiments of this specification, and does not necessarily include all the components shown in the figure.

[0130] 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.

[0131] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and 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.

[0132] The computer-readable media of this embodiment includes permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device.

[0133] 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.

[0134] Based on the same concept, corresponding to any of the above-mentioned embodiments, 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.

[0135] Those 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 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.

[0136] In addition, to simplify the description and discussion, and to avoid obscuring the understanding of the embodiments of the present application, well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided figures. Furthermore, devices may be shown in block diagram form to avoid obscuring the understanding of the embodiments of the present application, and this also takes into account the fact that the implementation details of these block diagram devices are highly dependent on the platform on which the embodiments of the present application will be implemented (i.e., these details should be fully understood by those skilled in the art). Where specific details (e.g., circuits) are set forth to describe the exemplary embodiments of the present application, it will be apparent to those skilled in the art that the embodiments of the present application can be implemented without these specific details or with variations therefrom. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0137] Although the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations of these embodiments will be apparent to those skilled in the art based on the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may utilize the discussed embodiments.

[0138] 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 scope of protection of the present application.

Claims

1. An engine misfire detection method, characterized in that: include: Acquiring vehicle operating data and an engine misfire signal; wherein the engine misfire signal is the engine speed change rate; a clutch is provided between the engine and the motor; when the clutch is closed, the engine and the motor are connected, and the engine speed and the motor speed are synchronized; Determining whether the vehicle meets a preset predicted misfire condition based on the vehicle operating data and the engine misfire signal, and if so, determining a target engine cylinder based on the engine misfire signal, including: For each cylinder's engine speed change rate during an engine operating cycle, the cylinder whose engine speed change rate exceeds a preset change rate threshold is selected as the target engine cylinder; wherein, when the vehicle meets the predicted misfire conditions, there is a possibility of misdiagnosis of a misfire fault; 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 meeting a preset difference condition, it is determined that the target engine cylinder is misfired.

2. The method according to claim 1, characterized in that The vehicle operating data includes engine water temperature, vehicle speed, engine operating time, engine speed, and engine load; and determining whether the vehicle meets a preset predicted misfire condition based on the vehicle operating 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 operating 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 exceeding 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 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.

4. The method according to claim 1, wherein Controlling the target engine cylinder to stop fuel injection includes: The target engine cylinder is controlled to stop injecting fuel within a preset number of engine operating cycles.

5. The method according to claim 1, wherein 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 fuel injection is stopped and the engine speed change rate before fuel injection is stopped being less than a preset difference threshold, it is determined that the engine misfire signal after fuel injection is stopped and the engine misfire signal before fuel injection is stopped meet a preset difference condition.

6. 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: generating 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.

7. The method according to claim 6, 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.

8. A vehicle, characterized in that: The vehicle comprises: a memory for storing executable program code; A processor is 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 7.

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