A method of and apparatus for controlling the speed of an engine

Abstract

The application discloses an engine rotating speed control method and a rotating speed control device, and the engine rotating speed control method comprises the following steps: determining that the engine is in a stable working condition; and performing at least one cycle of fuel injection amount correction processing to correct the fuel injection amount of the cylinders and reduce the rotating speed difference between the cylinders in the stable working condition. It can be seen that the technical scheme can correct the fuel injection amount of each cylinder to reduce the rotating speed difference between the cylinders when the engine is in the stable working condition, so that the rotating speeds of different cylinders have good consistency, the noise and vibration problems caused by the large rotating speed difference between the cylinders are avoided, and the stability and safety of the engine are improved.

Description

Technical Field

[0001] This application relates to the field of engine speed control technology, and more specifically, to an engine speed control method and speed control device. Background Technology

[0002] With the continuous development of science and technology, various types of vehicles have become commonplace in people's daily lives, bringing great convenience. The engine is the power unit of a vehicle, and the vehicles used in daily life employ low-speed, multi-cylinder engines.

[0003] For low-speed multi-cylinder engines, noise and vibration problems are prone to occur during engine operation, affecting the engine's stability and safety. Summary of the Invention

[0004] In view of this, this application provides an engine speed control method and speed control device, the scheme of which is as follows:

[0005] A method for controlling the speed of an engine, the engine having a plurality of cylinders, the method comprising:

[0006] Ensure the engine is in a stable operating condition;

[0007] Under the stable operating conditions, at least one cycle of fuel injection quantity correction processing is performed to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

[0008] Preferably, in the above-described speed control method, under the stable operating condition, at least one cycle of fuel injection quantity correction processing is performed, including:

[0009] The fuel injection quantity of each cylinder is corrected one by one to complete one cycle of fuel injection quantity correction processing;

[0010] After completing one cycle of fuel injection quantity correction processing, it is determined whether the speed difference between the cylinders is less than the set threshold.

[0011] If so, end the speed control process;

[0012] If not, execute the next cycle of fuel injection quantity correction process until the speed difference between the cylinders is less than the set threshold.

[0013] Preferably, in the above-described speed control method, the method for correcting the fuel injection quantity of the cylinder during a one-cycle fuel injection quantity correction process includes:

[0014] Determine the fuel injection quantity correction coefficient for the cylinder;

[0015] The fuel injection quantity of the cylinder is corrected based on the fuel injection quantity correction coefficient.

[0016] Preferably, in the above-described speed control method, the method for determining the fuel injection quantity correction coefficient includes:

[0017] Determine the rotational speed of the cylinder and the average rotational speed of the cylinder;

[0018] Based on the difference between the cylinder's rotational speed and the average rotational speed, a fuel injection quantity correction factor for the cylinder is determined; wherein the absolute value of the fuel injection quantity correction factor is positively correlated with the absolute value of the difference, and has the opposite sign to the difference.

[0019] Based on the fuel injection quantity correction factor, the fuel injection quantity correction coefficient is obtained; wherein the fuel injection quantity correction coefficient is the sum of 1 and the fuel injection quantity correction factor.

[0020] Preferably, in the above-described speed control method, the method for determining the speed of the cylinder and the average speed of the cylinder includes:

[0021] Obtain the crankshaft speed of the engine;

[0022] Based on the crankshaft speed, the speed of each cylinder is determined;

[0023] The average rotational speed of the cylinders is determined based on the rotational speed of each cylinder.

[0024] This application also provides an engine speed control device, the speed control device comprising:

[0025] The determination module is used to determine that the engine is in a stable operating condition;

[0026] The processing module is used to perform at least one cycle of fuel injection quantity correction processing under the stable operating conditions to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

[0027] Preferably, in the above-mentioned speed control device, the processing module includes:

[0028] The first processing unit is used to correct the fuel injection quantity of the cylinder one by one, and complete one cycle of fuel injection quantity correction processing.

[0029] The judgment unit is used to determine whether the speed difference between the cylinders is less than a set threshold after completing one cycle of fuel injection quantity correction processing.

[0030] If so, end the speed control process;

[0031] If not, execute the next cycle of fuel injection quantity correction process until the speed difference between the cylinders is less than the set threshold.

[0032] Preferably, in the above-mentioned speed control device, the processing module includes: a first processing unit, which is used to correct the fuel injection quantity of the cylinder during a cycle of fuel injection quantity correction processing;

[0033] The first processing unit includes: a sub-processing unit for determining the fuel injection quantity correction coefficient of the cylinder; and a correction sub-unit for correcting the fuel injection quantity of the cylinder based on the fuel injection quantity correction coefficient.

[0034] Preferably, in the above-mentioned speed control device, the sub-processing unit is used to determine the speed of the cylinder and the average speed of the cylinder, determine the injection quantity correction factor of the cylinder based on the difference between the cylinder speed and the average speed, and obtain the injection quantity correction coefficient based on the injection quantity correction factor; wherein, the absolute value of the injection quantity correction factor is positively correlated with the absolute value of the difference and has the opposite sign to the difference; the injection quantity correction coefficient is the sum of 1 and the injection quantity correction factor.

[0035] Preferably, in the above-mentioned speed control device, the sub-processing unit is used to acquire the crankshaft speed of the engine, determine the speed of each cylinder based on the crankshaft speed, and determine the average speed of the cylinder based on the speed of each cylinder.

[0036] As described above, the engine speed control method and speed control device provided in this application include: determining that the engine is in a stable operating condition; and under the stable operating condition, performing at least one cycle of fuel injection quantity correction processing to correct the fuel injection quantity of the cylinders and reduce the speed difference between the cylinders. Therefore, the technical solution of this application can correct the fuel injection quantity of each cylinder under stable engine operating conditions to reduce the speed difference between the cylinders, thereby enabling better consistency in the speed of different cylinders and avoiding problems such as noise and vibration caused by large speed differences between cylinders, thus improving the stability and safety of the engine. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0039] Figure 1 A flowchart illustrating an engine speed control method provided in an embodiment of this application;

[0040] Figure 2 This application provides a flowchart of a method for performing at least one cycle of fuel injection quantity correction processing under stable operating conditions, as described in this embodiment.

[0041] Figure 3 A flowchart illustrating a method for correcting the fuel injection quantity of a cylinder during a single cycle of fuel injection quantity correction processing, as provided in this application embodiment.

[0042] Figure 4 A flowchart illustrating a method for determining the cylinder fuel injection quantity correction coefficient provided in this application embodiment;

[0043] Figure 5 A schematic diagram illustrating the principle of measuring crankshaft speed according to an embodiment of this application;

[0044] Figure 6 A flowchart illustrating another engine speed control method provided in this application embodiment;

[0045] Figure 7 This is a schematic diagram illustrating the principle of correcting the cylinder fuel injection quantity based on the embodiments of this application;

[0046] Figure 8 This is a schematic diagram of the structure of a speed control device provided in an embodiment of this application;

[0047] Figure 9 This is a schematic diagram of the structure of a processing module provided in an embodiment of this application;

[0048] Figure 10 This is a schematic diagram of the structure of a first processing unit provided in an embodiment of this application; Detailed Implementation

[0049] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0050] As described in the background section, low-speed multi-cylinder engines are prone to noise and vibration problems during engine operation, which affect the engine's stability and safety.

[0051] The inventors discovered that for low-speed multi-cylinder engines, if there is a large difference in the speed between different cylinders, it will cause noise and vibration problems during engine operation. The main factor causing the large difference in the speed between different cylinders is the large difference in the amount of fuel injected by the injectors in different cylinders.

[0052] In view of the above, this application provides an engine speed control method and a speed control device, the speed control method comprising:

[0053] Ensure the engine is in a stable operating condition;

[0054] Under the stable operating conditions, at least one cycle of fuel injection quantity correction processing is performed to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

[0055] The technical solution of this application can correct the fuel injection quantity of each cylinder when the engine is under stable operating conditions, so as to reduce the difference in speed between the cylinders, thereby enabling the speed of different cylinders to have better consistency, avoiding noise and vibration problems caused by large differences in speed between cylinders, and improving the stability and safety of the engine.

[0056] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] refer to Figure 1 As shown, Figure 1 This is a flowchart illustrating an engine speed control method provided in an embodiment of this application. The engine has multiple cylinders, and the control method includes:

[0058] Step S11: Determine that the engine is in a stable operating condition.

[0059] The stable operating condition of an engine refers to a condition in which the engine has completed preheating, entered normal operation, and there are no changes in speed or load within a certain period of time.

[0060] Step S12: Under the stable operating conditions, perform at least one cycle of fuel injection quantity correction processing to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

[0061] As mentioned above, differences in the amount of fuel injected into the cylinders will lead to differences in cylinder speed. When this difference is large, it will result in a significant difference in cylinder speed, which in turn will cause noise and vibration problems during engine operation.

[0062] The speed control method provided in this application embodiment can perform at least one cycle of fuel injection quantity correction processing when the engine is under stable operating conditions, so as to correct the fuel injection quantity of the cylinder, reduce the difference in speed between the cylinders, thereby solving the noise and vibration problems caused by the difference in speed of different cylinders, and improving the stability and safety of the engine during operation.

[0063] In step S12 above, the method for performing at least one cycle of fuel injection quantity correction processing under the stable operating condition is as follows: Figure 2 As shown.

[0064] refer to Figure 2 As shown, Figure 2 This application provides a flowchart of a method for performing at least one cycle of fuel injection quantity correction processing under stable operating conditions, the method comprising:

[0065] Step S21: Correct the fuel injection quantity of each cylinder one by one to complete one cycle of fuel injection quantity correction processing.

[0066] Step S22: After completing one cycle of fuel injection quantity correction processing, determine whether the speed difference between the cylinders is less than the set threshold.

[0067] Step S23: If yes, end the speed control process.

[0068] Step S24: If not, perform the next cycle of fuel injection quantity correction process until the speed difference between the cylinders is less than the set threshold.

[0069] In the speed control method provided in this application embodiment, if the speed difference between the cylinders is not less than a set threshold after a cycle of fuel injection quantity correction processing, the next cycle of fuel injection quantity correction processing can be performed based on the correction result of the previous cycle until the speed difference between the cylinders is less than the set threshold, so that each cylinder has a relatively consistent speed.

[0070] The threshold value can be set based on requirements. The smaller the threshold value, the higher the consistency of the rotational speed of each cylinder. Generally, the threshold value can be set to no more than 10 revolutions per minute.

[0071] In this embodiment of the application, the method for correcting the fuel injection quantity of the cylinder during a cycle of fuel injection quantity correction processing is as follows: Figure 3 As shown.

[0072] refer to Figure 3 As shown, Figure 3 A flowchart illustrating a method for correcting the fuel injection quantity of a cylinder during a single-cycle fuel injection quantity correction process, provided in this application embodiment, includes:

[0073] Step S31: Determine the fuel injection quantity correction coefficient for the cylinder;

[0074] Step S32: Based on the fuel injection quantity correction coefficient, correct the fuel injection quantity of the cylinder.

[0075] Each cylinder has a corresponding fuel injection quantity correction coefficient. Based on the fuel injection quantity correction coefficient corresponding to the cylinder, the fuel injection quantity of the cylinder is corrected to reduce the speed difference between the cylinders.

[0076] The method for determining the fuel injection quantity correction coefficient is as follows: Figure 4 As shown.

[0077] refer to Figure 4 As shown, Figure 4 A flowchart of a method for determining a cylinder fuel injection quantity correction coefficient provided in this application embodiment, the method comprising:

[0078] Step S41: Determine the rotational speed of the cylinder and the average rotational speed of the cylinder.

[0079] Step S42: Determine the fuel injection quantity correction factor for the cylinder based on the difference between the cylinder's rotational speed and the average rotational speed.

[0080] The absolute value of the fuel injection quantity correction factor is positively correlated with the absolute value of the difference. A larger difference indicates a greater difference between the cylinder speed and the average speed, requiring a larger adjustment in the fuel injection quantity. Conversely, the fuel injection quantity correction factor has the opposite sign to the difference. A positive difference indicates that the cylinder speed is greater than the average speed, requiring a reduction in the fuel injection quantity to decrease the cylinder speed; in this case, the fuel injection quantity correction factor is negative.

[0081] Step S43: Obtain the fuel injection quantity correction coefficient based on the fuel injection quantity correction factor.

[0082] Wherein, the fuel injection quantity correction coefficient is the sum of 1 and the fuel injection quantity correction factor.

[0083] In this embodiment, a fuel injection quantity correction factor is determined based on the average speed of each cylinder, and then the fuel injection quantity correction coefficient corresponding to each cylinder is determined. When correcting the fuel injection quantity of a cylinder, the fuel injection quantity is multiplied by the corresponding fuel injection quantity correction coefficient to obtain the corrected fuel injection quantity of the cylinder, thereby reducing the difference between the cylinder speed and the average speed.

[0084] As can be seen, in the technical solution of this application, the fuel injection quantity of each cylinder is corrected based on the average speed of the cylinder, so as to reduce the difference between the speed of each cylinder and the average speed of the cylinder, thereby reducing the difference in speed between each cylinder.

[0085] In this embodiment of the application, the method for determining the average cylinder speed and the cylinder speed includes:

[0086] First, the crankshaft speed of the engine is obtained. Second, based on the crankshaft speed, the speed of each cylinder is determined. There is a corresponding relationship between the crankshaft speed and the speed of each cylinder; the speed of each cylinder can be determined based on the crankshaft speed. Finally, based on the speed of each cylinder, the average speed of the cylinders is determined; the average speed is the average of the speeds of all cylinders.

[0087] A sensor can be installed in the engine to detect crankshaft rotation data, and the crankshaft speed can be determined based on the crankshaft rotation data detected by the sensor.

[0088] For multi-cylinder engines, there is a corresponding relationship between the rotational speed of each cylinder and the rotational speed of the crankshaft. Based on this relationship and the crankshaft speed, the rotational speed of each cylinder can be determined separately.

[0089] Once the rotational speed of each cylinder is determined, the rotational speeds of each cylinder are summed, and the sum is divided by the number of cylinders to obtain the average rotational speed of the cylinders.

[0090] refer to Figure 5 As shown, Figure 5 This is a schematic diagram illustrating the principle of measuring crankshaft speed according to an embodiment of this application. The engine includes a crankshaft 11, and each cylinder is connected to the crankshaft 11 via a piston 12. A sensor 13 is provided for detecting the crankshaft speed. The sensor 13 is connected to a vehicle speed control device so that the speed control device can determine the crankshaft speed based on the data detected by the sensor 13.

[0091] The speed control device can be an ECU, capable of executing speed control methods. When each cylinder is working, the ECU has its own corresponding currently operating ignition cylinder and its corresponding cylinder speed.

[0092] Based on the above-described method for determining cylinder speed and average cylinder speed, the speed control method of this application embodiment will be further described. In this case, the speed control method can be as follows: Figure 6 As shown.

[0093] refer to Figure 6 As shown, Figure 6 This is a flowchart illustrating another engine speed control method provided in an embodiment of this application. The method includes:

[0094] Step S51: Determine that the engine is operating under stable conditions.

[0095] Step S52: Determine the difference between the rotational speed of each cylinder and the average rotational speed of the cylinder.

[0096] Under different stable operating conditions, it is necessary to determine the speed of each cylinder and the average speed of the cylinders separately.

[0097] Step S53: Determine the fuel injection quantity correction factor for each cylinder based on the difference.

[0098] Step S54: Determine the injection quantity correction coefficient for each cylinder based on the injection quantity correction factor.

[0099] The fuel injection quantity of each cylinder is corrected based on the fuel injection quantity correction coefficient of each cylinder.

[0100] Step S55: After correcting the fuel injection quantity of the cylinder based on the fuel injection quantity correction coefficient, determine whether the cylinder speed difference is less than the set threshold.

[0101] If the speed is less than the set threshold, it indicates that the speed difference between the cylinders is small and they have relatively consistent speeds. Conversely, it indicates that at least two cylinders have large speed differences, and it is necessary to redetermine the cylinder speed and the average cylinder speed based on the corrected fuel injection quantity for each cylinder. Then, perform a cycle of fuel injection quantity correction processing until the speeds of all cylinders are less than the set threshold.

[0102] refer to Figure 7 As shown, Figure 7 This is a schematic diagram illustrating the principle of correcting the cylinder fuel injection quantity based on the embodiments of this application. The horizontal axis represents time t, the vertical axis represents the fuel injection quantity n, the horizontal dashed line represents the average speed, the four peak positions of the solid curve correspond to the fuel injection quantities of the four cylinders respectively, and the dashed curve represents the desired correction result.

[0103] When the peak position corresponding to the cylinder is below the horizontal dashed line, it indicates that the cylinder speed is less than the average speed. A fuel injection quantity correction coefficient greater than 1 is needed to increase the fuel injection quantity, thereby increasing the cylinder speed and reducing the difference between the cylinder speed and the average cylinder speed. When the peak position corresponding to the cylinder is above the horizontal dashed line, it indicates that the cylinder speed is greater than the average speed. A fuel injection quantity correction coefficient less than 1 is needed to reduce the fuel injection quantity, thereby decreasing the cylinder speed and reducing the difference between the cylinder speed and the average cylinder speed.

[0104] As can be seen from the above description, the speed control method provided in this application can measure the crankshaft speed and the speed difference between each cylinder, and correct the cylinder fuel injection quantity based on the difference between the speed of each cylinder and the average speed of the cylinder, so as to reduce the speed difference between cylinders, improve speed stability, and solve the noise and vibration problems caused by cylinder speed differences.

[0105] Based on the above embodiments, another embodiment of this application provides a speed control device capable of executing the above speed control method, wherein the speed control device can be an ECU.

[0106] refer to Figure 8 As shown, Figure 8 This is a schematic diagram of a speed control device provided in an embodiment of this application. The speed control device includes:

[0107] Determining module 10, the determining module 10 is used to determine that the engine is in a stable operating condition;

[0108] The processing module 20 is used to perform at least one cycle of fuel injection quantity correction processing under the stable operating conditions to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

[0109] The structure of the above-mentioned processing module 20 can be as follows: Figure 9 As shown.

[0110] refer to Figure 9 As shown, Figure 9 This is a schematic diagram of a processing module provided in an embodiment of this application. The processing module 20 includes:

[0111] The first processing unit 201 is used to correct the fuel injection quantity of the cylinder one by one, and complete one cycle of fuel injection quantity correction processing.

[0112] The judgment unit 202 is used to determine whether the speed difference between the cylinders is less than a set threshold after completing one cycle of fuel injection quantity correction processing. If yes, the speed control process ends; if no, the next cycle of fuel injection quantity correction processing is executed until the speed difference between the cylinders is less than the set threshold.

[0113] The processing module 20 includes a first processing unit 201, which is used to correct the fuel injection quantity of the cylinder during a cycle of fuel injection quantity correction processing.

[0114] The structure of the first processing unit 201 can be as follows: Figure 10 As shown.

[0115] refer to Figure 10 As shown, Figure 10 This is a schematic diagram of the structure of a first processing unit provided in an embodiment of this application. The first processing unit 201 includes: a sub-processing unit 201a, which is used to determine the fuel injection quantity correction coefficient of the cylinder; and a correction sub-unit 201b, which is used to correct the fuel injection quantity of the cylinder based on the fuel injection quantity correction coefficient.

[0116] The sub-processing unit 201a is used to determine the rotational speed of the cylinder and the average rotational speed of the cylinder, determine the injection quantity correction factor of the cylinder based on the difference between the rotational speed of the cylinder and the average rotational speed, and obtain the injection quantity correction coefficient based on the injection quantity correction factor; wherein the absolute value of the injection quantity correction factor is positively correlated with the absolute value of the difference and has the opposite sign to the difference; the injection quantity correction coefficient is the sum of 1 and the injection quantity correction factor.

[0117] The subprocessing unit 201a is used to obtain the crankshaft speed of the engine, determine the speed of each cylinder based on the crankshaft speed, and determine the average speed of the cylinder based on the speed of each cylinder.

[0118] The speed control device described in this application embodiment can execute the above-described speed control method, and the implementation of its corresponding function can refer to the speed control method described in the above embodiment.

[0119] As described above, the engine speed control method and speed control device provided in this application include: determining that the engine is in a stable operating condition; and under the stable operating condition, performing at least one cycle of fuel injection quantity correction processing to correct the fuel injection quantity of the cylinders and reduce the speed difference between the cylinders. Therefore, the technical solution of this application can correct the fuel injection quantity of each cylinder under stable engine operating conditions to reduce the speed difference between the cylinders, thereby enabling better consistency in the speed of different cylinders and avoiding problems such as noise and vibration caused by large speed differences between cylinders, thus improving the stability and safety of the engine.

[0120] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0121] It should be noted that, in the description of this application, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0122] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0123] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the speed of an engine, characterized in that, The engine has multiple cylinders, and the speed control method includes: Ensure the engine is in a stable operating condition; Under the stable operating conditions, at least one cycle of fuel injection quantity correction processing is performed to correct the fuel injection quantity of the cylinders and reduce the difference in speed between the cylinders, including: The fuel injection quantity of each cylinder is corrected one by one to complete one cycle of fuel injection quantity correction processing; After completing one cycle of fuel injection quantity correction processing, it is determined whether the speed difference between the cylinders is less than the set threshold. If so, end the speed control process; If not, execute the next cycle of fuel injection quantity correction process until the speed difference between the cylinders is less than the set threshold. The method for correcting the fuel injection quantity of the cylinder includes: Obtain the crankshaft speed of the engine; Based on the crankshaft speed, the speed of each cylinder is determined; The average rotational speed of the cylinders is determined based on the rotational speed of each cylinder. Based on the difference between the cylinder's rotational speed and the average rotational speed, a fuel injection quantity correction factor for the cylinder is determined. The absolute value of the fuel injection quantity correction factor is positively correlated with the absolute value of the difference, and has the opposite sign to the difference. Based on the fuel injection quantity correction factor, the fuel injection quantity correction coefficient is obtained, wherein the fuel injection quantity correction coefficient is the sum of 1 and the fuel injection quantity correction factor; The fuel injection quantity of the cylinder is corrected based on the fuel injection quantity correction coefficient.

2. The speed control method according to claim 1, characterized in that, The stable operating condition refers to a condition where the engine has completed preheating, entered normal operation, and there are no changes in speed or load within a certain period of time.

3. The speed control method according to claim 1, characterized in that, The engine is equipped with a sensor for detecting crankshaft rotation data. Based on the crankshaft rotation data detected by the sensor, the crankshaft speed is determined.

4. The speed control method according to claim 1, characterized in that, There is a corresponding relationship between the rotational speed of each cylinder and the rotational speed of the crankshaft. Based on this relationship and the crankshaft speed, the rotational speed of each cylinder is determined.

5. The speed control method according to claim 1, characterized in that, The average cylinder speed is obtained by summing the speeds of each cylinder and dividing the sum by the number of cylinders.

6. An engine speed control device for executing the engine speed control method according to any one of claims 1 to 5, characterized in that, The speed control device includes: The determination module is used to determine that the engine is in a stable operating condition; The processing module is used to perform at least one cycle of fuel injection quantity correction processing under the stable operating conditions to correct the fuel injection quantity of the cylinder and reduce the difference in speed between the cylinders.

7. The speed control device according to claim 6, characterized in that, The processing module includes: The first processing unit is used to correct the fuel injection quantity of the cylinder one by one, and complete one cycle of fuel injection quantity correction processing. The judgment unit is used to determine whether the speed difference between the cylinders is less than a set threshold after completing one cycle of fuel injection quantity correction processing. If so, end the speed control process; If not, execute the next cycle of fuel injection quantity correction process until the speed difference between the cylinders is less than the set threshold.

8. The speed control device according to claim 6, characterized in that, The processing module includes: a first processing unit, which is used to correct the fuel injection quantity of the cylinder during a cycle of fuel injection quantity correction processing; The first processing unit includes: a sub-processing unit for determining the fuel injection quantity correction coefficient of the cylinder; and a correction sub-unit for correcting the fuel injection quantity of the cylinder based on the fuel injection quantity correction coefficient.

9. The speed control device according to claim 8, characterized in that, The sub-processing unit is used to determine the cylinder's rotational speed and average rotational speed, determine the cylinder's fuel injection quantity correction factor based on the difference between the cylinder's rotational speed and the average rotational speed, and obtain the fuel injection quantity correction coefficient based on the fuel injection quantity correction factor; wherein, the absolute value of the fuel injection quantity correction factor is positively correlated with the absolute value of the difference, and has the opposite sign to the difference; the fuel injection quantity correction coefficient is the sum of 1 and the fuel injection quantity correction factor.

10. The speed control device according to claim 9, characterized in that, The subprocessing unit is used to acquire the crankshaft speed of the engine, determine the speed of each cylinder based on the crankshaft speed, and determine the average speed of the cylinder based on the speed of each cylinder.

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