Method, device and vehicle for determining cylinder misfire

Abstract

The present invention discloses a method, device and vehicle for determining cylinder misfire. The method comprises: determining the first cycle time of a cylinder in an engine in a current working cycle, and determining the second cycle time of the cylinder in a previous working cycle of the current working cycle and the third cycle time of the cylinder in a previous working cycle of the current working cycle; determining the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time; determining the target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; determining the state of the target cylinder based on the target misfire characteristic value, wherein the state is used to characterize whether the cylinder has misfired. The present invention solves the technical problem of low accuracy in engine misfire diagnosis.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a method and device for determining cylinder misfire, and a vehicle. Background Art

[0002] In the related art, cylinder misfire detection is usually performed by the crankshaft speed fluctuation method. This method can use the time when the crankshaft sweeps through the selected window of a cylinder and its adjacent cylinders to determine the angular acceleration of the cylinder. The angular acceleration can be used as a misfire diagnosis signal, and the misfire diagnosis signal is compared with a calibrated threshold. When the misfire diagnosis signal exceeds the calibrated threshold, it can be indicated that the engine is misfired. However, since this method needs to make a difference comparison with the cylinder segment time, it is inevitably affected by the manufacturing error of the signal wheel and the uneven combustion of the engine. Therefore, there is still a technical problem of low accuracy in engine misfire diagnosis.

[0003] With respect to the technical problem of low accuracy of engine misfire diagnosis in the above-mentioned related technologies, no effective solution has been proposed so far. Summary of the invention

[0004] Embodiments of the present invention provide a method, device and vehicle for determining cylinder misfire, so as to at least solve the technical problem of low accuracy in engine misfire diagnosis.

[0005] According to one aspect of an embodiment of the present invention, a method for determining cylinder misfire is provided. The method may include: determining the first cycle time of a cylinder in an engine in a current working cycle, and determining the second cycle time of the cylinder in a previous working cycle of the current working cycle and the third cycle time of the cylinder in a previous working cycle of the current working cycle; determining the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time; determining the target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; determining the state of the target cylinder based on the target misfire characteristic value, wherein the state is used to characterize whether the cylinder has misfired.

[0006] Optionally, based on the target misfire characteristic value, the state of the target cylinder is determined, including: determining the segmented time difference of the target cylinder in the previous working cycle of the current working cycle; determining the misfire characteristic value of the target cylinder in the previous working cycle based on the segmented time difference of the target cylinder in the previous working cycle; and determining the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value.

[0007] Optionally, determining the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value includes: determining the misfire data of the target cylinder in the current working cycle based on the difference between the target misfire characteristic value and the misfire characteristic value; and determining the state of the target cylinder based on the misfire data.

[0008] Optionally, based on the misfire data, determining the state of the target cylinder includes: comparing the misfire data with a misfire threshold; in response to the misfire data being not less than the misfire threshold, determining the state of the target cylinder to be a misfire state, or in response to the misfire data being less than the misfire threshold, determining the state of the target cylinder to be a non-misfire state.

[0009] Optionally, based on the first cycle time, the second cycle time and the third cycle time, the segment time difference of the cylinder is determined, including: determining the difference between the first cycle time and the third cycle time of the cylinder, and determining the time compensation amount of the cylinder based on the difference; determining the sum of the third cycle time of the cylinder and the time compensation amount, and determining the difference between the second cycle time and the sum as the segment time difference of the cylinder.

[0010] Optionally, based on the segment time difference, determining the target misfire characteristic of the cylinder includes: obtaining the target segment time difference of the target cylinder in the current working cycle and the segment time difference of the previous cylinder of the target cylinder in the cylinder; and determining the target misfire characteristic value of the target cylinder based on the difference between the target segment time difference and the segment time difference.

[0011] Optionally, the first cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the current working cycle, the second cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle, and the third cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle.

[0012] Optionally, a segmented window is determined, wherein the segmented window includes a starting point and a length of the segmented window, and the starting point is a compression top dead center of a cylinder corresponding to the segmented window.

[0013] According to another aspect of an embodiment of the present invention, a cylinder misfire determination device is also provided. The device may include: a first determination unit, used to determine the first cycle time of a cylinder in an engine in a current working cycle, and to determine the second cycle time of the cylinder in a previous working cycle of the current working cycle and the third cycle time of the cylinder in a previous working cycle of the current working cycle; a second determination unit, used to determine the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time; a third determination unit, used to determine the target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; and a fourth determination unit, used to determine the state of the target cylinder based on the target misfire characteristic value, wherein the state is used to characterize whether the cylinder has misfired.

[0014] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the cylinder misfire determination method of the embodiment of the present invention.

[0015] According to another aspect of an embodiment of the present invention, a processor is provided, which is used to run a program, wherein the method for determining cylinder misfire according to an embodiment of the present invention is executed when the program is run.

[0016] According to another aspect of an embodiment of the present invention, a vehicle is further provided, and the vehicle is used to execute the method for determining cylinder misfire according to an embodiment of the present invention.

[0017] In an embodiment of the present invention, the first cycle time of a cylinder in the engine in the current working cycle is determined, and the second cycle time of the cylinder in the previous working cycle of the current working cycle and the third cycle time of the previous working cycle of the cylinder are determined; based on the first cycle time, the second cycle time and the third cycle time, the segmented time difference of the cylinder is determined; based on the segmented time difference of the cylinder, the target misfire characteristic value of the cylinder is determined; based on the target misfire characteristic value, the state of the target cylinder is determined, wherein the state is used to characterize whether the cylinder has misfired. That is, the embodiment of the present invention determines the segmented time difference of the cylinder by analyzing the first cycle time, the second cycle time and the third cycle time of different working cycles of the same cylinder in the engine, obtains the target misfire characteristic value of the cylinder based on the segmented time difference, and can judge whether the cylinder has misfired by the target characteristic value. That is, taking into account the compensation of the information transmission delay between cylinders through the segmented time difference of the cylinders, the problem of low accuracy of engine misfire diagnosis caused by long transmission delay due to the use of many cylinders is avoided, thereby solving the technical problem of low accuracy of engine misfire diagnosis and achieving the technical effect of improving the accuracy of engine misfire diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 is a flow chart of a method for determining cylinder misfire according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the segmented time of a cylinder according to an embodiment of the present invention;

[0021] Figure 3is a schematic diagram of a cylinder misfire determination device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] Example 1

[0025] According to an embodiment of the present invention, an embodiment of a method for determining cylinder misfire is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0026] Figure 1 is a flow chart of a method for determining cylinder misfire according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0027] Step S102, determining the first cycle time of the cylinder in the engine in the current working cycle, and determining the second cycle time of the cylinder in the previous working cycle of the current working cycle and the third cycle time of the cylinder in the previous working cycle of the current working cycle.

[0028] In the technical solution provided in the above step S102 of the present invention, during the operation of the engine, the time of the cylinder in the current working cycle of the engine can be determined as the first cycle time, the time of the cylinder in the previous working cycle of the current working cycle can be determined as the second cycle time, and the time of the cylinder in the previous working cycle of the current working cycle can be determined as the third cycle time. Among them, the engine can include multiple cylinders, for example, it can include eight cylinders, four cylinders, etc. The cylinder can include a crankshaft, a camshaft, and a window, etc. A working cycle of the engine can include: intake, compression, power and exhaust processes. It should be noted that this is only for example, and no specific restrictions are made on the number of cylinders in the engine and its working cycle.

[0029] Optionally, during the operation of the engine, the time at which the crankshaft of the cylinder sweeps across the specified rotation angle interval of the cylinder can be determined as the segmented window of the cylinder. Based on different working cycles, the time at which the crankshaft of the cylinder sweeps across the segmented window of the cylinder can be determined as the cycle time under the corresponding working cycle. For example, the time at which the crankshaft of the cylinder sweeps across the segmented window of the cylinder in the current working cycle can be determined as the first cycle time; the time at which the crankshaft of the cylinder sweeps across the segmented window of the cylinder in the previous working cycle of the current working cycle can be determined as the second cycle time; the time at which the crankshaft of the cylinder sweeps across the segmented window of the cylinder in the previous working cycle of the current working cycle can be determined as the third cycle time. Among them, the first cycle time can be expressed by t 1 The second cycle time can be expressed as t 2 The third cycle time can be expressed as t 3 The segmented window may be a window for selecting the same crankshaft rotation angle interval for the same cylinder in each working cycle. It should be noted that no specific restrictions are imposed on the rotation angle interval specified by the segmented window.

[0030] Step S104: determining the cylinder segment time difference based on the first cycle time, the second cycle time and the third cycle time.

[0031] In the technical solution provided in step S104 of the present invention, after determining the first cycle time, the second cycle time and the third cycle time of the cylinder in the engine, the first cycle time, the second cycle time and the third cycle time can be calculated to determine the segment time difference of the cylinder. The segment time difference can be used to represent the difference between different cycle times, which can be expressed as x i Represents the segment time difference of cylinder i.

[0032] Optionally, since there may be transmission delays in the working cycle of the engine cylinders, this may result in reduced accuracy in engine misfire diagnosis. Therefore, in an embodiment of the present invention, a time compensation amount may be first determined through the first cycle time and the third cycle time to compensate for the transmission delay, and then a segmented time difference may be determined based on the time compensation amount and the second time cycle and the third time cycle. The segmented time difference may be used to accurately predict the state of the engine at the current moment, thereby achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0033] Step S106, determining a target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder.

[0034] In the technical solution of step S106 of the present invention, after the segment time difference is determined based on the first cycle time, the second cycle time and the third cycle time, the target misfire characteristic value of the cylinder can be determined by the segment time difference of the cylinder, wherein the target misfire characteristic value can be used to determine whether the corresponding cylinder has misfired, and can be the misfire characteristic value of the target cylinder, which can be obtained by Dlut i represents the target misfire characteristic value of the target cylinder i.

[0035] For example, the segmented time difference of cylinder 1 in the current working cycle can be determined, and the segmented time difference of the previous cylinder of the target cylinder in the current working cycle can also be determined. After obtaining the two segmented time differences based on the above steps, the target misfire characteristic value of cylinder 1 can be determined through the segmented time difference of the target cylinder and the segmented time difference of the previous cylinder. Based on the target misfire characteristic value of the target cylinder, it can be determined whether a misfire occurs in the target cylinder.

[0036] Step S108, determining the state of the target cylinder based on the target misfire characteristic value, wherein the state is used to characterize whether misfire occurs in the cylinder.

[0037] In the technical solution of step S108 of the present invention, the target misfire characteristic value of the cylinder can be determined based on the segmented time difference of the cylinder, and the state of the target cylinder can be determined based on the target misfire characteristic value, so as to judge whether the target cylinder has misfired, wherein the state of the target cylinder can include a misfire state and a non-misfire state. The misfire state can be used to characterize that the target cylinder has misfired, and the non-misfire state can be used to characterize that the target cylinder has not misfired. The target cylinder can be the cylinder that currently needs to be tested for whether a misfire has occurred, and can be represented by i.

[0038] Optionally, the target misfire characteristic value of the target cylinder of the current working cycle can be determined, and the misfire characteristic value of the target cylinder of the previous cycle can also be determined. After obtaining the target misfire characteristic value and the misfire characteristic value of the target cylinder based on the above steps, the misfire data of the target cylinder can be calculated, and the state of the target cylinder can be judged based on the misfire data, wherein the misfire data can be used to characterize whether a misfire occurs in the target cylinder.

[0039] For example, in the process of judging the state of the cylinder based on the target misfire characteristic value, a misfire threshold value can be set. After the misfire data is calculated by the target misfire characteristic value, the misfire data and the misfire threshold value can be judged to determine the size relationship between the two. Based on the size relationship, it can be judged whether the cylinder has misfired. For example, if the misfire data is greater than or equal to the misfire threshold value, it can be said that the cylinder is in a misfire state at this time; if the misfire data is less than the misfire threshold value, it can be said that the cylinder is in a non-misfire state at this time. It should be noted that this is only for illustration, and no specific restrictions are imposed on the method and process of determining the state of the cylinder based on the target misfire characteristic value. As long as the target misfire characteristic value of the target cylinder is determined based on the segmented time difference of different cylinders in the same working cycle, and then the process and method of determining whether the target cylinder has misfired based on different target misfire characteristic values ​​of the target cylinder under different working cycles are all within the protection scope of the embodiments of the present invention.

[0040] In the related art, the angular acceleration of a cylinder is determined by the time when the crankshaft sweeps through the selected window of a cylinder and its adjacent cylinders. The angular acceleration can be used as a misfire diagnosis signal. Based on the misfire diagnosis signal, it is determined whether the cylinder is misfired. In this process, it is necessary to make a difference comparison with the segmented time of the adjacent cylinders. Therefore, there is still a technical problem of low accuracy in engine misfire diagnosis. In the embodiment of the present invention, since the segmented time difference can be determined by the cycle time of different working cycles of the same cylinder, the misfire characteristic value corresponding to the cylinder can be further determined by the segmented time difference, so as to determine whether the cylinder is misfired. During the operation of the engine, since there will be a delay in the information transmission between the cylinders, the delay can be compensated by determining the segmented time difference of the cylinders, thereby avoiding the problem of long transmission delay due to the use of many cylinders, and thus achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0041] In the above steps S102 to S108 of the embodiment of the present invention, the first cycle time of the cylinder in the current working cycle of the engine is determined, and the second cycle time of the cylinder in the previous working cycle of the current working cycle and the third cycle time of the cylinder in the previous working cycle of the current working cycle are determined; based on the first cycle time, the second cycle time and the third cycle time, the segmented time difference of the cylinder is determined; based on the segmented time difference of the cylinder, the target misfire characteristic value of the cylinder is determined; based on the target misfire characteristic value, the state of the target cylinder is determined, wherein the state is used to characterize whether the cylinder has misfired. That is, the embodiment of the present invention determines the segmented time difference of the cylinder by analyzing the first cycle time, the second cycle time and the third cycle time of different working cycles of the same cylinder in the engine, obtains the target misfire characteristic value of the cylinder based on the segmented time difference, and can judge whether the cylinder has misfired by the target characteristic value. That is, taking into account the compensation of the information transmission delay between cylinders through the segmented time difference of the cylinders, the problem of low accuracy of engine misfire diagnosis caused by long transmission delay due to the use of many cylinders is avoided, thereby solving the technical problem of low accuracy of engine misfire diagnosis and achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0042] The above method of this embodiment is further introduced below.

[0043] As an optional implementation method, step S108, based on the target misfire characteristic value, determines the state of the target cylinder, including: determining the segmented time difference of the target cylinder in the previous working cycle of the current working cycle; determining the misfire characteristic value of the target cylinder in the previous working cycle based on the segmented time difference of the target cylinder in the previous working cycle; determining the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value.

[0044] In this embodiment, in the process of determining the state of the corresponding target cylinder based on the target misfire characteristic value, the segment time difference of the target cylinder in the previous working cycle of the current working cycle can be determined, and the misfire characteristic value of the target cylinder in the previous working cycle can be determined based on the determined segment time difference of the previous working cycle, and then based on the misfire characteristic value and the target misfire characteristic value, it can be determined whether the state of the target cylinder is a misfire state, wherein the misfire characteristic value can be the misfire characteristic value of the target cylinder in the previous working cycle; and the target misfire characteristic value can be the misfire characteristic value of the target cylinder in the current working cycle.

[0045] Optionally, the segment time difference of the previous cylinder of the target cylinder of the current working cycle in the current working cycle can be determined, and the segment time difference of the target cylinder of the current cycle can also be determined. Based on the segment time difference between the target cylinder of the current working cycle and the adjacent cylinders, the target misfire characteristic value of the target cylinder of the current cycle can be determined.

[0046] Optionally, the segment time difference of the previous cylinder of the target cylinder of the previous working cycle in the working cycle can be determined, and the segment time difference of the target cylinder of the working cycle can also be determined. Based on the segment time difference between the target cylinder of the previous working cycle and the adjacent cylinder, the misfire characteristic value of the target cylinder of the previous working cycle can be determined, wherein the misfire characteristic value of the target cylinder of the previous working cycle can be calculated using lut i 'express.

[0047] For example, it can be determined that the cylinder i-1 before the target cylinder i has a current working cycle t 1 The segment time difference x i-1 , it can also be determined that the target cylinder i is in the current working cycle t 1 The segment time difference x i , based on the time difference between the two segments x i-1 and x i , the current working cycle t can be determined 1 The target misfire characteristic value Dlut of the target cylinder i i .

[0048] For another example, the last working cycle t of the target cylinder i can be determined 2 The time difference of each segment can also determine the target cylinder i in the previous working cycle t 2 Based on the two segment time differences, the last working cycle t 2 The misfire characteristic value lut of the target cylinder i i ′.

[0049] In the embodiment of the present invention, since the segmented time difference of the corresponding cylinder can be determined by the cycle time of different working cycles of the same cylinder, the misfire characteristic value in the corresponding working cycle can be further determined by the segmented time difference of different working cycles of the cylinder and the segmented time difference of the previous cylinder of the corresponding working cycle. For example, the target misfire characteristic value of the target cylinder can be determined by the segmented time difference of the target cylinder of the current working cycle and the segmented time difference of the previous cylinder of the current working cycle, so as to determine whether the target cylinder has misfired based on the target misfire characteristic value. In this process, since there may be delays in information transmission between cylinders, the delay can be compensated by determining the segmented time difference of the cylinders, thereby avoiding the problem of long transmission delay due to the use of many cylinders, and further solving the technical problem of low accuracy of engine misfire diagnosis.

[0050] As an optional implementation method, step S108, based on the misfire characteristic value and the target misfire characteristic value, determines the state of the target cylinder, including: based on the difference between the target misfire characteristic value and the misfire characteristic value, determines the misfire data of the target cylinder in the current working cycle; based on the misfire data, determines the state of the target cylinder.

[0051] In this embodiment, in the process of determining the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value, the misfire data of the target cylinder of the current working cycle can be determined by the difference between the target misfire characteristic value of the target cylinder of the current working cycle and the misfire characteristic value of the target cylinder of the previous working cycle, so as to determine whether the state of the target cylinder is in a misfire state by judging the size of the misfire data, wherein the misfire data can be used to characterize whether a misfire occurs in the target cylinder.

[0052] For example, after obtaining the target misfire characteristic value of the target cylinder of the current working cycle and the misfire characteristic value of the target cylinder of the previous working cycle, the misfire data of the target cylinder can be determined by the following formula:

[0053] Dlut i =lut i -lut i '

[0054] Among them, i can be used to represent the target cylinder; Dlut i Can be used to represent the misfire data of target cylinder i; lut i It can be used to represent the target misfire characteristic value of the target cylinder i in the current working cycle; lut i ′ can be used to represent the misfire characteristic value of the target cylinder i in the previous working cycle.

[0055] As an optional implementation method, step S108, based on the misfire data, determines the state of the target cylinder, including: comparing the misfire data with a misfire threshold; in response to the misfire data being not less than the misfire threshold, determining that the state of the target cylinder is a misfire state, or in response to the misfire data being less than the misfire threshold, determining that the state of the target cylinder is a non-misfire state.

[0056] In this embodiment, in the process of determining the state of the target cylinder based on the misfire data, the misfire data and the misfire threshold can be compared to determine the state of the target cylinder. If the misfire data is not less than the misfire threshold, it can be determined that the state of the target cylinder is in a misfire state, which can indicate that a misfire has occurred in the target cylinder at this time; if the misfire data is less than the misfire threshold, it can be determined that the state of the target cylinder is in a non-misfire state, which can indicate that a misfire has not occurred in the target cylinder at this time, wherein the misfire threshold can be preset data or self-set data, which is only used as an example here, and no specific limitation is imposed on the size of the misfire threshold.

[0057] Optionally, if one wants to test a certain cylinder of the engine, one can determine the misfire data of the cylinder by determining the misfire characteristic value and the target misfire characteristic value of the cylinder, and subtracting the two. If the misfire data is greater than or equal to the misfire threshold, and the misfire characteristic value and the target misfire characteristic value have a large difference in size, then it can be said that a misfire has occurred in the cylinder; if the misfire data is less than the misfire threshold, and the misfire characteristic value and the target misfire characteristic value are close in size, then it can be said that no misfire has occurred in the cylinder.

[0058] Optionally, the misfire threshold can be determined by conducting a real vehicle test on a chassis dynamometer, using the engine electronic control software or misfire generator hardware to create a misfire in the engine cylinder. In this process, the misfire data of the engine speed and engine load as the operating point can be counted to determine the misfire threshold. It should be noted that this is only an example, and does not specifically limit the method and process for determining the misfire threshold.

[0059] In the embodiment of the present invention, since the process of determining the misfire threshold can be subjected to a real vehicle experiment, and the cylinder misfire situation can be continuously simulated during the experiment to determine the size of the misfire data in this situation, after multiple experiments, a misfire data is determined as the misfire threshold, thereby improving the accuracy of the misfire threshold, and further achieving the technical effect of improving the accuracy of engine misfire diagnosis during the process of engine misfire diagnosis.

[0060] As an optional implementation method, step S104 determines the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time, including: determining the difference between the first cycle time and the third cycle time of the cylinder, and determining the time compensation amount of the cylinder based on the difference; determining the sum of the third cycle time of the cylinder and the time compensation amount, and determining the difference between the second cycle time and the sum as the segmented time difference of the cylinder.

[0061] In this embodiment, in the process of determining the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time, the difference between the first cycle time and the third cycle time of the cylinder can be determined, and the difference is determined as the time compensation amount of the cylinder. The segmented time difference of the cylinder in the current working cycle is determined by summing the third cycle time of the cylinder and the time compensation amount, wherein the time compensation amount can be used to compensate for the transmission delay during the operation of the cylinder, and can be expressed by cmp.

[0062] For example, after obtaining the first cycle time, the second cycle time, and the third cycle time of the cylinder, the time compensation amount of the cylinder can be determined by the following formula:

[0063]

[0064] Among them, t 1 Can be used to indicate the first cycle time of the current working cycle, t 3 It can be used to indicate the third working cycle time of the previous working cycle of the current working cycle.

[0065] For another example, after the time compensation amount of the cylinder is determined based on the above steps, the segment time difference of the cylinder can be determined by the following formula:

[0066] x i =t 2 -t 3 -cmp

[0067] Among them, x i It can be used to represent the time difference of the cylinder i segment, t 2 It can be used to indicate the second cycle time of the previous working cycle of the current working cycle.

[0068] In the related art, in the process of judging engine misfire, it is necessary to make a difference comparison with the segmented time of adjacent cylinders, so there is a technical problem of low accuracy of engine misfire diagnosis. In the embodiment of the present invention, the transmission delay of the cylinder during different working cycles is compensated by the time compensation amount, and the segmented time difference of the cylinder is determined based on the time compensation, thereby reducing the influence of the time delay on the accuracy of misfire diagnosis, thereby achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0069] As an optional implementation method, step S106, based on the segment time difference, determines the target misfire characteristic of the cylinder, including: obtaining the target segment time difference of the target cylinder in the current working cycle and the segment time difference of the previous cylinder of the target cylinder in the cylinder; based on the difference between the target segment time difference and the segment time difference, determining the target misfire characteristic value of the target cylinder.

[0070] In this embodiment, in the process of determining the target misfire characteristic value of the cylinder based on the segment time difference, the target segment time difference of the target cylinder in the current working cycle and the segment time difference of the previous cylinder of the target cylinder can be obtained, and the target misfire characteristic value of the target cylinder can be determined based on the difference between the above two segment time differences, wherein the target segment time difference can be the segment time difference of the target cylinder.

[0071] Optionally, the time compensation amount of the cylinder can be determined by the first cycle time and the third cycle time of the previous cylinder of the target cylinder of the current working cycle, and then the segment time difference of the cylinder can be determined based on the second cycle time and the time compensation amount. The target cylinder time compensation amount can also be determined by the first cycle time and the third cycle time of the target cylinder of the current working cycle, and then the target segment time difference of the target cylinder can be determined based on the second cycle time and the time compensation amount. Based on the difference between the target segment time difference and the segment time difference, the target misfire characteristic value of the target cylinder can be determined.

[0072] For example, after obtaining the target segment time difference of the target cylinder of the current working cycle and the segment time difference of the previous cylinder, the target misfire characteristic value of the target cylinder can be determined by the following formula:

[0073]

[0074] Among them, lut i It can be used to represent the target misfire characteristic value of the target cylinder i in the current working cycle; N can be used to represent a standardized constant; x i Can be used to represent the target segment time difference of target cylinder i; x i-1It can be used to represent the segment time difference of the previous cylinder i-1 of the target cylinder i.

[0075] As an optional implementation method, step S102, the first cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the current working cycle, the second cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle, and the third cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle.

[0076] In this embodiment, the first cycle time may be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the current working cycle; the second cycle time may be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the previous working cycle; the third working cycle time may be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the previous working cycle, wherein the segmented time window may be the rotation angle interval of the crankshaft sweeping through the cylinder. No specific limitation is made to the rotation angle interval here.

[0077] Optionally, sensors may be deployed at the crankshaft and camshaft of the cylinder. For example, a crankshaft position sensor may be installed at the crankshaft, and a camshaft position sensor may be installed at the camshaft. During engine operation, the above two sensors may be used to scan the crankshaft through a specified rotation angle interval of the cylinder as a segment window of the cylinder.

[0078] As an optional implementation manner, step S102, determining a segmented window, wherein the segmented window includes a starting point and a length of the segmented window, and the starting point is a compression top dead center of the cylinder corresponding to the segmented window.

[0079] In this embodiment, before determining the first cycle time, the second cycle time and the third cycle time of the cylinder, it is necessary to first determine the cylinder segment window, wherein the segment window may include a starting point and a length of the segment window. The starting point may be the compression top dead center of the cylinder corresponding to the segment window.

[0080] Optionally, for any working cycle, the segmented window of the cylinder within the crankshaft angle (e.g., 720°) can be determined by the crankshaft position sensor and the camshaft position sensor. For any cylinder, the starting point of the window in the cylinder is the crankshaft angle relative to the compression top dead center of the cylinder.

[0081] For example, the length of the segment window can be determined by the following formula:

[0082]

[0083] Among them, I can be used to represent the length of the segment window, and a can be used to represent the number of cylinders in the engine.

[0084] In an embodiment of the present invention, the first cycle time of a cylinder in the engine in the current working cycle is determined, and the second cycle time of the cylinder in the previous working cycle of the current working cycle and the third cycle time of the previous working cycle of the cylinder are determined; based on the first cycle time, the second cycle time and the third cycle time, the segmented time difference of the cylinder is determined; based on the segmented time difference of the cylinder, the target misfire characteristic value of the cylinder is determined; based on the target misfire characteristic value, the state of the target cylinder is determined, wherein the state is used to characterize whether the cylinder has misfired. That is, the embodiment of the present invention determines the segmented time difference of the cylinder by analyzing the first cycle time, the second cycle time and the third cycle time of different working cycles of the same cylinder in the engine, obtains the target misfire characteristic value of the cylinder based on the segmented time difference, and can judge whether the cylinder has misfired by the size of the target characteristic value. That is, taking into account the compensation of the information transmission delay between cylinders through the segmented time difference of the cylinders, the problem of low accuracy of engine misfire diagnosis caused by long transmission delay due to the use of many cylinders is avoided, thereby solving the technical problem of low accuracy of engine misfire diagnosis and achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0085] Example 2

[0086] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0087] Engine misfire means that one or more cylinders of the engine do not work or do not work enough. It is usually caused by abnormal fuel injection caused by injector blockage or failure of gasoline engine ignition coil, which causes incomplete or no combustion of fuel. After the engine misfires, the vehicle will experience severe shaking, insufficient engine power, weak acceleration, large engine speed fluctuations, abnormal noise, increased fuel consumption, and a large amount of hydrocarbons and carbon monoxide are easily produced in the exhaust, polluting the environment. Even when multiple cylinders misfire, the engine may not start. In view of the serious impact of misfire on engine performance, engine misfire diagnosis has become one of the important detection contents of vehicle diagnosis.

[0088] In the related art, the angular acceleration of a cylinder is determined by the time it takes for the crankshaft to sweep through a selected window of a cylinder and its adjacent cylinders, and the angular acceleration is used as a misfire diagnosis signal. Based on the misfire diagnosis signal, it is determined whether the cylinder has misfired. In this process, since it is necessary to make a difference comparison with the segmented time of adjacent cylinders, there is still a technical problem of low accuracy in engine misfire diagnosis.

[0089] In a related technology, an engine misfire diagnosis method and vehicle are proposed, which may include: determining the first crankshaft angle interval and the second crankshaft angle interval of each cylinder; in one working cycle of the engine, for any cylinder, collecting the time required for the crankshaft to rotate through the first crankshaft angle interval of the cylinder and the time required for the crankshaft to rotate through the second crankshaft angle interval of the cylinder; for any cylinder, calculating the misfire characteristic value of the cylinder according to the time required for the crankshaft to rotate through the first crankshaft angle interval of the cylinder and the time required for the crankshaft to rotate through the second crankshaft angle interval of the cylinder; for any cylinder, comparing the misfire characteristic value of the cylinder with the misfire threshold to determine whether the cylinder is misfired. The engine misfire diagnosis method does not rely on the test results of other cylinders when determining whether a cylinder is misfired, thereby avoiding the influence of misfires in other cylinders.

[0090] In another related technology, an engine misfire diagnosis method and misfire diagnosis device are also proposed, which may include: first, selecting a window of the same crankshaft angle in each working cycle as a segmented window; second, measuring the time occupied by the segmented window in each working cycle; then, calculating the average angular acceleration of the segmented window in each working cycle from the time occupied by the segmented window in two adjacent or spaced working cycles; finally, judging whether the cylinder of the engine is misfired according to the difference m of the average angular acceleration of the segmented window in two adjacent or spaced working cycles. The engine misfire diagnosis method provided by the method does not have the problem of inaccurate angle division caused by the manufacturing deviation of the signal wheel, and can solve the problems of misjudgment and missed judgment in the misfire diagnosis of the engine, especially the asymmetric two-cylinder engine.

[0091] However, the above method does not take into account the delay in information transmission between cylinders. Therefore, the above method still has the technical problem of low accuracy in engine misfire diagnosis.

[0092] In order to solve the above problems, the present invention proposes a method, device and vehicle for determining cylinder misfire. The method may include the following steps: by selecting the rotation angle interval of the crankshaft sweeping the engine cylinder as the segmented window of the cylinder; collecting the time when the crankshaft sweeps through the segmented window of each cylinder in the current working cycle and the previous two working cycles; for a certain cylinder, using the time when the crankshaft sweeps through the segmented window of the cylinder in the current and previous two working cycles to calculate the misfire characteristic value; for any cylinder, comparing the misfire diagnosis characteristic value of the cylinder with the misfire threshold value obtained from actual vehicle experiments, judging whether the cylinder has misfired, thereby avoiding the problem of large delay error caused by multi-cylinder calculation, and further solving the technical problem of low accuracy of engine misfire diagnosis, and achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0093] The embodiments of the present invention are further described below.

[0094] In this embodiment, Figure 2 is a schematic diagram of the segmented time of a cylinder according to an embodiment of the present invention, such as Figure 2 As shown, the segmented time of the cylinder may include work cycle 1, work cycle 2 and work cycle 3. If the current cycle is work cycle 1, the intermediate cycle is called work cycle 2, and the initial work cycle is called work cycle 3, wherein work cycle 2 is the previous work cycle of work cycle 1, and work cycle 3 is the previous work cycle of the previous work cycle. Each work cycle contains the nodes of compression top dead center of cylinder 1, compression top dead center of cylinder 2, compression top dead center of cylinder 3 and compression top dead center of cylinder 4.

[0095] In this embodiment, the time of the cylinder in the engine in the current working cycle can be determined as the first cycle time, the time of the cylinder in the previous working cycle of the current working cycle can be determined as the second cycle time, and the time of the cylinder in the previous working cycle of the current working cycle can be determined as the third cycle time, wherein the engine can be an eight-cylinder naturally aspirated engine; the engine can include multiple cylinders. It should be noted that this is only for example, and no specific limitation is imposed on the engine and its working cycle.

[0096] Optionally, during the operation of the engine, the crankshaft of the cylinder sweeps through the rotation angle interval of the cylinder as the segmented window of the cylinder. Based on different working cycles, the time for the crankshaft of the cylinder to sweep through the segmented window of the cylinder can be determined as the cycle time under the corresponding working cycle. For example, the time for the crankshaft of the cylinder to sweep through the segmented window of the cylinder under the current working cycle can be determined as the first cycle time, wherein the segmented window can be a window of the rotation angle interval of the same crankshaft selected by the same cylinder in each working cycle. The first cycle time can be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the current working cycle; the second cycle time can be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the previous working cycle; the third working cycle time can be the time for the crankshaft in the cylinder of the engine to sweep through the segmented window of the cylinder in the previous working cycle, wherein the segmented time window can be the rotation angle interval of the crankshaft sweeping through the cylinder. No specific restrictions are made on the rotation angle interval here.

[0097] Optionally, sensors may be deployed at the crankshaft and camshaft of the cylinder. For example, a crankshaft position sensor may be installed at the crankshaft, and a camshaft position sensor may be installed at the camshaft. During engine operation, the above two sensors may be used to scan the crankshaft through a specified rotation angle interval of the cylinder as a segment window of the cylinder.

[0098] Optionally, for any working cycle, the segmented window of the cylinder within the crankshaft angle (e.g., 720°) can be determined by the crankshaft position sensor and the camshaft position sensor. For any cylinder, the starting point of the window in the cylinder is the crankshaft angle relative to the compression top dead center of the cylinder.

[0099] For example, the length of the segment window can be determined by the following formula:

[0100]

[0101] Among them, I can be used to represent the length of the segment window, and α can be used to represent the number of cylinders in the engine.

[0102] In this embodiment, since the cylinders of the engine are in a working cycle, there may be a transmission delay, which may cause the accuracy of the engine misfire diagnosis to be reduced. Therefore, in the embodiment of the present invention, the time compensation amount can be first determined by the first cycle time and the third cycle time, so that the transmission delay can be compensated, and then the segment time difference can be determined based on the time compensation amount and the second time cycle and the third time cycle, thereby achieving the technical effect of improving the accuracy of the engine misfire diagnosis.

[0103] Optionally, in the process of determining the segmented time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time, the difference between the first cycle time and the third cycle time of the cylinder can be determined, and the difference is determined as the time compensation amount of the cylinder. The segmented time difference of the cylinder in the current working cycle is determined by summing the third cycle time of the cylinder and the time compensation amount, wherein the time compensation amount can be used to compensate for the transmission delay during the operation of the cylinder.

[0104] For example, after obtaining the first cycle time, the second cycle time, and the third cycle time of the cylinder, the time compensation amount of the cylinder can be determined by the following formula:

[0105]

[0106] Among them, cmp can be used to represent the time compensation of the cylinder, t 1 Can be used to indicate the first cycle time of the current working cycle, t 3 It can be used to indicate the third working cycle time of the previous working cycle of the current working cycle.

[0107] For another example, after the time compensation amount of the cylinder is determined based on the above steps, the segment time difference of the cylinder can be determined by the following formula:

[0108] x i =t2 -t 3 -cmp

[0109] Among them, x i It can be used to represent the time difference of the cylinder i segment, t 2 It can be used to indicate the second cycle time of the previous working cycle of the current working cycle.

[0110] In the related art, in the process of judging engine misfire, it is necessary to make a difference comparison with the segmented time of adjacent cylinders, so there is a technical problem of low accuracy of engine misfire diagnosis. In the embodiment of the present invention, the transmission delay of the cylinder during different working cycles is compensated by the time compensation amount, and the segmented time difference of the cylinder is determined based on the time compensation, thereby reducing the influence of the time delay on the accuracy of misfire diagnosis, thereby achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0111] Optionally, the time compensation amount of the cylinder can be determined by the first cycle time and the third cycle time of the previous cylinder of the target cylinder of the current working cycle, and then the segment time difference of the cylinder can be determined based on the second cycle time and the time compensation amount. The target cylinder time compensation amount can also be determined by the first cycle time and the third cycle time of the target cylinder of the current working cycle, and then the target segment time difference of the target cylinder can be determined based on the second cycle time and the time compensation amount. Based on the difference between the target segment time difference and the segment time difference, the target misfire characteristic value of the target cylinder can be determined.

[0112] For example, after obtaining the target segment time difference of the target cylinder of the current working cycle and the segment time difference of the previous cylinder, the target misfire characteristic value of the target cylinder can be determined by the following formula:

[0113]

[0114] Among them, lut i It can be used to represent the target misfire characteristic value of the target cylinder i in the current working cycle; N can be used to represent a standardized constant; x i Can be used to represent the target segment time difference of target cylinder i; x i-1 It can be used to represent the segment time difference of the previous cylinder i-1 of the target cylinder i.

[0115] In this embodiment, after determining the target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder, it is possible to determine whether the target cylinder is misfired by performing relevant calculations on the target misfire characteristic value, wherein the target misfire characteristic value may be the misfire characteristic value of the target cylinder. The state of the target cylinder may include a misfire state and a non-misfire state, wherein the misfire state may be used to characterize that the target cylinder has misfired, and the non-misfire state may be used to characterize that the target cylinder has not misfired.

[0116] Optionally, the target misfire characteristic value of the target cylinder of the current working cycle can be determined, and the misfire characteristic value of the target cylinder of the previous cycle can also be determined. After obtaining the target misfire characteristic value and the misfire characteristic value of the target cylinder based on the above steps, the misfire data of the target cylinder can be calculated, and the state of the target cylinder can be judged based on the misfire data.

[0117] Optionally, the segment time difference of the previous cylinder of the target cylinder of the current working cycle in the current working cycle can be determined, and the segment time difference of the target cylinder of the current cycle can also be determined. Based on the segment time difference between the target cylinder of the current working cycle and the adjacent cylinders, the target misfire characteristic value of the target cylinder of the current cycle can be determined.

[0118] Optionally, the segment time difference of the previous cylinder of the target cylinder of the previous working cycle in the working cycle can be determined, and the segment time difference of the target cylinder of the working cycle can also be determined. Based on the segment time difference between the target cylinder of the previous working cycle and the adjacent cylinder, the misfire characteristic value of the target cylinder of the previous working cycle can be determined.

[0119] In the embodiment of the present invention, since the segment time difference of the corresponding cylinder can be determined by the cycle time of different working cycles of the same cylinder, the misfire characteristic value in the corresponding working cycle can be further determined by the segment time difference of different working cycles of the cylinder and the segment time difference of the previous cylinder of the corresponding working cycle. For example, the target misfire characteristic value of the target cylinder can be determined by the segment time difference of the target cylinder of the current working cycle and the segment time difference of the previous cylinder of the current working cycle, so as to determine whether the target cylinder has misfired based on the target misfire characteristic value. In this process, since the segment time difference is determined only by the cycle time of the same cylinder, the problem of long transmission delay caused by the use of multiple cylinders is avoided, thereby solving the technical problem of low accuracy of engine misfire diagnosis.

[0120] Optionally, in the process of determining the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value, the misfire data of the target cylinder of the current working cycle can be determined by the difference between the target misfire characteristic value of the target cylinder of the current working cycle and the misfire characteristic value of the target cylinder of the previous working cycle, thereby determining whether the state of the target cylinder is in a misfire state by judging the size of the misfire data, wherein the misfire data can be used to characterize whether a misfire occurs in the target cylinder.

[0121] For example, after obtaining the target misfire characteristic value of the target cylinder of the current working cycle and the misfire characteristic value of the target cylinder of the previous working cycle, the misfire data of the target cylinder can be determined by the following formula:

[0122] Dlut i =lut i -lut i '

[0123] Among them, i can be used to represent the target cylinder; Dlut i Can be used to represent the misfire data of target cylinder i; lut i It can be used to represent the target misfire characteristic value of the target cylinder i in the current working cycle; lut i ′ can be used to represent the misfire characteristic value of the target cylinder i in the previous working cycle.

[0124] Optionally, in the process of determining the state of the target cylinder based on the misfire data, the misfire data and the misfire threshold can be compared to determine the state of the target cylinder. If the misfire data is not less than the misfire threshold, it can be determined that the state of the target cylinder is in a misfire state, which can indicate that a misfire has occurred in the target cylinder at this time; if the misfire data is less than the misfire threshold, it can be determined that the state of the target cylinder is in a non-misfire state, which can indicate that no misfire has occurred in the target cylinder at this time, wherein the misfire threshold can be preset data or self-set data, which is only used as an example here, and no specific limitation is imposed on the size of the misfire threshold.

[0125] Optionally, if one wants to test a certain cylinder of the engine, one can determine the misfire data of the cylinder by determining the misfire characteristic value and the target misfire characteristic value of the cylinder, and subtracting the two. If the misfire data is greater than or equal to the misfire threshold, it can be said that a misfire has occurred in the cylinder; if the misfire data is less than the misfire threshold, it can be said that no misfire has occurred in the cylinder.

[0126] In the embodiment of the present invention, the determination of the misfire threshold can be carried out by conducting a real vehicle experiment on a chassis dynamometer, using the engine electronic control software or the misfire generator hardware to produce a misfire in the cylinder of the engine. In this process, the misfire data of the engine speed and the engine load as the operating point can be statistically analyzed to determine the misfire threshold, thereby improving the accuracy of the misfire threshold, and further achieving the technical effect of improving the accuracy of the engine misfire diagnosis in the process of diagnosing the engine misfire. It should be noted that this is only an example, and does not specifically limit the method and process for determining the misfire threshold.

[0127] The embodiment of the present invention determines the segmented time difference of the cylinder by analyzing the first cycle time, the second cycle time and the third cycle time of different working cycles of the same cylinder in the engine, and obtains the target misfire characteristic value of the cylinder based on the segmented time difference, and can judge whether the cylinder has misfired by the size of the target characteristic value. That is, considering that the information transmission delay between cylinders is compensated by the segmented time difference of the cylinders, the problem of low accuracy of engine misfire diagnosis caused by long transmission delay due to the use of many cylinders is avoided, thereby solving the technical problem of low accuracy of engine misfire diagnosis and achieving the technical effect of improving the accuracy of engine misfire diagnosis.

[0128] Example 3

[0129] According to an embodiment of the present invention, a cylinder misfire determination device is also provided. It should be noted that the cylinder misfire determination device can be used to execute the cylinder misfire determination method in embodiment 1.

[0130] Figure 3 Schematic diagram of a cylinder misfire determination device according to an embodiment of the present invention. Figure 3 As shown, the cylinder misfire determination device 300 may include: a first determination unit 302 , a second determination unit 304 , a third determination unit 306 and a fourth determination unit 308 .

[0131] The first determination unit 302 is used to determine the first cycle time of the cylinder in the engine in the current working cycle, and determine the second cycle time of the cylinder in the previous working cycle of the current working cycle and the third cycle time of the cylinder in the previous working cycle of the current working cycle.

[0132] The second determining unit 304 is used to determine the cylinder segment time difference based on the first cycle time, the second cycle time and the third cycle time.

[0133] The third determination unit 306 is configured to determine a target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder.

[0134] The fourth determination unit 308 is configured to determine a state of a target cylinder based on the target misfire characteristic value, wherein the state is used to indicate whether misfire occurs in the cylinder.

[0135] Optionally, the fourth determination unit 308 may include: a first determination module, used to determine the segmented time difference of the target cylinder in the previous working cycle of the current working cycle; a second determination module, used to determine the misfire characteristic value of the target cylinder in the previous working cycle based on the segmented time difference of the target cylinder in the previous working cycle; and a third determination module, used to determine the state of the target cylinder based on the misfire characteristic value and the target misfire characteristic value.

[0136] Optionally, the third determination module may include: a first determination submodule, used to determine the misfire data of the target cylinder in the current working cycle based on the target misfire characteristic value and the difference between the misfire characteristic value; and a second determination submodule, used to determine the state of the target cylinder based on the misfire data.

[0137] Optionally, the fourth determination unit 308 may further include: a comparison module, used to compare the misfire data with the misfire threshold; a fourth determination module, used to determine that the state of the target cylinder is a misfire state in response to the misfire data being not less than the misfire threshold, or to determine that the state of the target cylinder is a non-misfire state in response to the misfire data being less than the misfire threshold.

[0138] Optionally, the second determination unit 304 may include: a fifth determination module, used to determine the difference between the first cycle time and the third cycle time of the cylinder, and determine the time compensation amount of the cylinder based on the difference; a sixth determination module, used to determine the sum of the third cycle time of the cylinder and the time compensation amount, and determine the difference between the second cycle time and the sum as the segmented time difference of the cylinder.

[0139] Optionally, the third determination unit 306 may include: an acquisition module for acquiring a target segmented time difference of the target cylinder in the current working cycle and a segmented time difference of the previous cylinder of the target cylinder in the cylinder; and a seventh determination module for determining a target misfire characteristic value of the target cylinder based on the difference between the target segmented time difference and the segmented time difference.

[0140] Optionally, the device may further include: a fifth determining unit, configured to determine a segmented window, wherein the segmented window includes a starting point and a length of the segmented window, and the starting point is a compression top dead center of a cylinder corresponding to the segmented window.

[0141] In an embodiment of the present invention, a first determination unit is used to determine a first cycle time of a cylinder in a current working cycle of an engine, and a second cycle time of a working cycle before the current working cycle and a third cycle time of a working cycle before the current working cycle of the cylinder are determined; a second determination unit is used to determine a segmented time difference of the cylinder based on the first cycle time, the second cycle time, and the third cycle time; a third determination unit is used to determine a target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; a fourth determination unit is used to determine a state of a target cylinder based on the target misfire characteristic value, wherein the state is used to characterize whether a misfire occurs in the cylinder, thereby solving the technical problem of low accuracy in engine misfire diagnosis and achieving the technical effect of improving the accuracy in engine misfire diagnosis.

[0142] Example 4

[0143] According to an embodiment of the present invention, a computer-readable storage medium is further provided. The storage medium includes a stored program, wherein the program executes the cylinder misfire determination method described in Embodiment 1.

[0144] Example 5

[0145] According to an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein the method for determining cylinder misfire described in Embodiment 1 is executed when the program is run.

[0146] Example 6

[0147] According to an embodiment of the present invention, a vehicle is further provided. The vehicle is used to execute the method for determining cylinder misfire according to an embodiment of the present invention.

[0148] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0149] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0151] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0152] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0153] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0154] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining cylinder misfire, characterized in that: include: Determine a first cycle time of a cylinder in an engine in a current working cycle, and determine a second cycle time of the cylinder in a previous working cycle of the current working cycle and a third cycle time of the cylinder in a previous working cycle of the current working cycle; determining a split time difference of the cylinder based on the first cycle time, the second cycle time, and the third cycle time; determining a target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; Determining a state of a target cylinder based on the target misfire characteristic value, wherein the state is used to indicate whether misfire occurs in the cylinder; Wherein, determining the segment time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time includes: determining the difference between the first cycle time and the third cycle time of the cylinder, and determining the time compensation amount of the cylinder based on the difference; determining the sum of the third cycle time of the cylinder and the time compensation amount, and determining the difference between the second cycle time and the sum as the segment time difference of the cylinder; Determining the target misfire characteristic value of the cylinder based on the segment time difference includes: acquiring the target segment time difference of the target cylinder in the current working cycle and the segment time difference of a cylinder before the target cylinder in the cylinder; determining the target misfire characteristic value of the target cylinder based on the difference between the target segment time difference and the segment time difference; Determining the state of the target cylinder based on the target misfire characteristic value includes: determining a segmented time difference of the target cylinder in the previous working cycle of the current working cycle; determining a misfire characteristic value of the target cylinder in the previous working cycle based on the segmented time difference of the target cylinder in the previous working cycle; and determining the state of the target cylinder based on the misfire characteristic value of the previous working cycle and the target misfire characteristic value.

2. The method according to claim 1, characterized in that Determining the state of the target cylinder based on the misfire characteristic value of the previous working cycle and the target misfire characteristic value includes: Determining misfire data of the target cylinder in the current working cycle based on a difference between the target misfire characteristic value and the misfire characteristic value of the previous working cycle; Based on the misfire data, a state of the target cylinder is determined.

3. The method according to claim 2, characterized in that Determining a state of the target cylinder based on the misfire data includes: comparing the misfire data to a misfire threshold; In response to the misfire data being not less than the misfire threshold, determining the state of the target cylinder is a misfire state, or in response to the misfire data being less than the misfire threshold, determining the state of the target cylinder is a non-misfire state.

4. The method according to claim 1, characterized in that: The first cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the current working cycle, the second cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle, and the third cycle time is the time it takes for the crankshaft in the engine to sweep across the segmented window of the cylinder in the previous working cycle of the current working cycle.

5. The method according to claim 4, characterized in that The method further comprises: The segmented window is determined, wherein the segmented window includes a starting point and a length of the segmented window, and the starting point is a compression top dead center of a cylinder corresponding to the segmented window.

6. A cylinder misfire determination device, characterized in that: include: A first determining unit is used to determine a first cycle time of a cylinder in the engine in a current working cycle, and determine a second cycle time of the cylinder in a previous working cycle of the current working cycle and a third cycle time of the cylinder in a previous working cycle of the current working cycle; a second determining unit, configured to determine a segment time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time; a third determination unit, configured to determine a target misfire characteristic value of the cylinder based on the segmented time difference of the cylinder; a fourth determination unit, configured to determine a state of a target cylinder based on the target misfire characteristic value, wherein the state is used to indicate whether misfire occurs in the cylinder; The second determining unit is used to determine the split time difference of the cylinder based on the first cycle time, the second cycle time and the third cycle time by the following steps: determining the difference between the first cycle time and the third cycle time of the cylinder, and determining the time compensation amount of the cylinder based on the difference; determining the sum of the third cycle time of the cylinder and the time compensation amount, and determining the difference between the second cycle time and the sum as the split time difference of the cylinder; The third determination unit is used to determine the target misfire characteristic value of the cylinder based on the segment time difference by the following steps: obtaining the target segment time difference of the target cylinder in the current working cycle and the segment time difference of the previous cylinder of the target cylinder in the cylinder; determining the target misfire characteristic value of the target cylinder based on the difference between the target segment time difference and the segment time difference; The fourth determination unit is used to determine the state of the target cylinder based on the target misfire characteristic value through the following steps: determining the segment time difference of the target cylinder in the previous working cycle of the current working cycle; determining the misfire characteristic value of the target cylinder in the previous working cycle based on the segment time difference of the target cylinder in the previous working cycle; determining the state of the target cylinder based on the misfire characteristic value of the previous working cycle and the target misfire characteristic value.

7. A vehicle, characterized in that: Used to perform the method according to any one of claims 1 to 5.

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