Gasoline engine knock control method and device

Abstract

The present application provides a gasoline engine knock control method and device, belonging to the field of engine control. The method can directly obtain the corresponding current characteristic curve parameters based on the current operating parameters of the engine, and compare them with a pre-stored standard characteristic curve to obtain the probability difference between the current knock probability and the standard knock probability, thereby indirectly determining the engine knock situation and judging whether the ignition angle is reasonable. This eliminates the need for a knock sensor and reduces control costs. When the ignition angle is unreasonable, the engine's ignition angle can be actively advanced or delayed based on the probability difference. Compared to the technical solution in the prior art that can only delay the ignition angle, this method also achieves more accurate control of engine knock, improving engine thermal efficiency while ensuring engine NVH.

Description

Technical Field

[0001] The present application relates to the field of engine control, and in particular to a gasoline engine knock control method and device. Background Art

[0002] With the increasing popularity of automobiles, people's expectations for vehicles are becoming increasingly higher. Fuel economy and NVH (Noise, Vibration, Harshness) have gradually become issues of concern to users during vehicle use. The thermal efficiency and operating smoothness of gasoline engines have a crucial impact on fuel economy and vehicle NVH.

[0003] In order to improve the thermal efficiency and smoothness of operation of gasoline engines, it is necessary to avoid the phenomenon of gasoline engine knock. Knocking refers to the situation where the gasoline engine cylinder is exploded due to factors such as incorrect air-fuel ratio and the pressure changes dramatically.

[0004] Traditional gasoline engine knock control solutions generally involve installing a knock sensor inside the engine. When the knock sensor detects knock, the ignition angle is delayed. This control solution requires a knock sensor and is expensive to control. Summary of the Invention

[0005] In view of this, the present application provides a gasoline engine knock control method and device, which can accurately control knock at a relatively low cost.

[0006] In one aspect, the present application provides a gasoline engine knock control method, the method comprising:

[0007] Get the current operating parameters of the engine.

[0008] The current operating condition parameters are substituted into the pre-stored parameter correspondence relationship to obtain the current characteristic curve parameters. The parameter correspondence relationship includes the correspondence between the operating condition parameters and the characteristic curve parameters.

[0009] The current characteristic curve is obtained according to the current characteristic curve parameters.

[0010] The current characteristic curve is compared with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve.

[0011] The ignition angle of the engine is adjusted according to the probability difference.

[0012] Optionally, the operating condition parameters include engine speed and load, and the characteristic curve parameters include mean and standard deviation. Substituting the current operating condition parameters into the pre-stored parameter correspondence relationship, the current characteristic curve parameters obtained include:

[0013] Substitute the current speed and current load into the parameter correspondence to obtain the current mean and current standard deviation.

[0014] The current characteristic curve is a normal distribution curve, and the current characteristic curve is obtained according to the current characteristic curve parameters, including:

[0015] A current characteristic curve is obtained according to the current mean and the current standard deviation. The current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

[0016] Optionally, comparing the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between a current knock probability in the current characteristic curve and a standard knock probability in the standard characteristic curve includes:

[0017] The knock ignition angle in the standard characteristic curve is substituted into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve.

[0018] A probability difference between the current knock probability and a standard knock probability is calculated, where the standard knock probability corresponds to the knock ignition angle in a standard characteristic curve. The standard characteristic curve is a normal distribution curve. The standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles when the engine is in a standard operating state. The engine being in a standard operating state means that the engine is operating at a preset speed and a preset load.

[0019] Alternatively, the integral of the standard characteristic curve on the closed interval [0, α] is the same as the preset knock cycle number, where α represents the knock ignition angle, and the preset knock cycle number represents the number of cycles in which the engine is allowed to produce knock in a preset number of cycles.

[0020] Optionally, adjusting the ignition angle of the engine according to the probability difference includes:

[0021] When the probability difference is greater than the preset probability difference, the magnitude relationship between the current knock probability and the standard knock probability is determined.

[0022] When the current knock probability is less than the standard knock probability, the ignition angle of the engine is advanced by a first preset angle.

[0023] When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

[0024] On the other hand, the present application provides a gasoline engine knock control device, the device comprising:

[0025] The operating condition acquisition module is configured to obtain the current operating condition parameters of the engine.

[0026] The parameter acquisition module is configured to substitute the current operating condition parameters into the pre-stored parameter correspondence relationship to obtain the current characteristic curve parameters, where the parameter correspondence relationship includes the correspondence between the operating condition parameters and the characteristic curve parameters.

[0027] The curve determination module is configured to obtain a current characteristic curve according to current characteristic curve parameters.

[0028] The difference acquisition module is configured to compare the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve.

[0029] The adjustment module is configured to adjust the ignition angle of the engine according to the probability difference.

[0030] Optionally, the operating condition parameters include engine speed and load, the characteristic curve parameters include mean and standard deviation, and the parameter acquisition module is configured as follows:

[0031] Substitute the current speed and current load into the parameter correspondence to obtain the current mean and current standard deviation.

[0032] The current characteristic curve is a normal distribution curve, and the curve determination module is configured as follows:

[0033] A current characteristic curve is obtained according to the current mean and the current standard deviation. The current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

[0034] Optionally, the difference acquisition module is configured to:

[0035] The knock ignition angle in the standard characteristic curve is substituted into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve.

[0036] A probability difference between the current knock probability and a standard knock probability is calculated, where the standard knock probability corresponds to the knock ignition angle in a standard characteristic curve. The standard characteristic curve is a normal distribution curve. The standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles when the engine is in a standard operating state. The engine being in a standard operating state means that the engine is operating at a preset speed and a preset load.

[0037] Alternatively, the integral of the standard characteristic curve on the closed interval [0, α] is the same as the preset knock cycle number, where α represents the knock ignition angle, and the preset knock cycle number represents the number of cycles in which the engine is allowed to produce knock in a preset number of cycles.

[0038] Optionally, the adjustment module is configured to:

[0039] When the probability difference is greater than the preset probability difference, the magnitude relationship between the current knock probability and the standard knock probability is determined.

[0040] When the current knock probability is less than the standard knock probability, the ignition angle of the engine is advanced by a first preset angle.

[0041] When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

[0042] By adopting the gasoline engine knock control method and device provided in the present application, the corresponding current characteristic curve parameters are obtained according to the current operating parameters of the engine, and compared with the pre-stored standard characteristic curve to obtain the probability difference between the current knock probability and the standard knock probability, and the engine's ignition angle is adjusted according to the probability difference. This can achieve accurate control of engine knock without setting up a knock sensor, thereby reducing control costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0044] Figure 1 A flowchart of a gasoline engine knock control method provided in an embodiment of the present application;

[0045] Figure 2 Another flow chart of the gasoline engine knock control method provided in an embodiment of the present application;

[0046] Figure 3 A schematic diagram of a characteristic curve of an engine in a gasoline engine knock control method provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram showing a comparison of characteristic curves of an engine in a gasoline engine knock control method provided in an embodiment of the present application;

[0048] Figure 5 Another comparative schematic diagram of the characteristic curves of the engine in the gasoline engine knock control method provided in an embodiment of the present application;

[0049] Figure 6 This is a structural diagram of the gasoline engine knock control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0051] With the advancement of automotive technology, users are increasingly demanding higher standards for their vehicles. For example, demands for fuel economy, emissions, and NVH (Noise, Vibration, and Harshness) performance are becoming increasingly stringent. These engine performance characteristics are closely related to engine calibration. Engine thermal efficiency determines fuel economy and emissions, and one way to improve thermal efficiency is to implement lean combustion. However, lean combustion can easily lead to knock, which affects NVH. Therefore, knock control strategies play a crucial role in improving engine fuel economy, emissions, and NVH.

[0052] Traditional knock control methods typically perform a series of operations based on the knock sensor's detection results. If the knock sensor continues to detect no knock, the control strategy maintains the current ignition angle without changing it. If the knock sensor continues to detect knock, the ignition angle is continuously delayed until the sensor detects no knock. The specific control strategy involves first delaying the ignition angle by a larger angle (e.g., 3°), then gradually delaying the ignition angle by 0.75°. If the ignition angle is delayed until the knock sensor detects no knock, the ignition angle is gradually advanced by a smaller angle (e.g., 0.75°) from the next cycle until the original ignition angle is reached. This traditional knock control method has the following shortcomings.

[0053] Traditional knock control methods operate passively and indirectly. Ignition angle control primarily relies on the knock sensor's monitoring of engine vibration, with control of the current cycle based on the knock sensor's determination of the previous cycle. Furthermore, the knock sensor's accuracy, installation location, and surroundings all affect knock determination. Furthermore, knock sensors are relatively expensive, and their installation on commercial vehicles increases both cost and pricing, impacting sales.

[0054] Traditional knock control methods do not actively advance the ignition angle. Due to certain production deviations during the engine mass production stage, engines with a lower compression ratio limit should have a corresponding advanced ignition angle to improve combustion efficiency. However, with traditional knock control methods, the ignition angle always remains at the calibrated ignition angle, failing to reach the optimal ignition angle and achieving the engine's optimal thermal efficiency. Even more disadvantageously, due to production consistency considerations, the calibration manufacturer sets the calibrated ignition angle 2-3° later than the optimal ignition angle, so engines under traditional knock control always operate in a low thermal efficiency range.

[0055] Since the delay angle is large, the advance angle is small, and there is no allowable deviation in the knock ignition angle, the ignition angle presents a typical sawtooth shape, resulting in a certain fluctuation in the combustion center, poor combustion stability, and high engine fuel consumption.

[0056] In order to solve the above problems, the present invention provides a method for controlling knock in a gasoline engine. Figure 1 As shown, the method includes steps S101, S102, S103, S104 and S105, wherein:

[0057] In step S101, the current operating parameters of the engine are obtained.

[0058] In step S102 , the current operating condition parameters are substituted into the pre-stored parameter correspondence relationship to obtain the current characteristic curve parameters. The parameter correspondence relationship includes the correspondence relationship between the operating condition parameters and the characteristic curve parameters.

[0059] In step S103 , a current characteristic curve is obtained according to the current characteristic curve parameters.

[0060] In step S104 , the current characteristic curve is compared with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve.

[0061] In step S105 , the ignition angle of the engine is adjusted according to the probability difference.

[0062] By adopting the gasoline engine knock control method provided in the present application, the corresponding current characteristic curve parameters are obtained according to the current operating parameters of the engine, and compared with the pre-stored standard characteristic curve to obtain the probability difference between the current knock probability and the standard knock probability, and the engine's ignition angle is adjusted according to the probability difference. This can achieve accurate control of engine knock without setting up a knock sensor, thereby reducing control costs.

[0063] The present application also provides another gasoline engine knock control method, which is executed by a vehicle-mounted control device, such as a vehicle controller. Figure 2 As shown, the method includes steps S201, S202, S203, S204 and S205, wherein:

[0064] In step S201, the current operating parameters of the engine are obtained.

[0065] In some optional embodiments, the current operating parameters include engine speed and load.

[0066] The engine speed and load can be obtained by the engine controller.

[0067] It can be understood that the technical solution provided in the embodiment of the present application does not require the additional installation of a knock sensor to monitor whether the engine has knock. Instead, it uses a specific prediction model based on the engine speed and load to predict the proportion of cycles in which knock may occur in multiple cycles of the engine, thereby inferring the knock situation of the engine, effectively reducing the implementation cost.

[0068] In step S202 , the current operating condition parameters are substituted into the pre-stored parameter correspondence relationship to obtain the current characteristic curve parameters. The parameter correspondence relationship includes the correspondence relationship between the operating condition parameters and the characteristic curve parameters.

[0069] In some optional embodiments, the characteristic curve parameters include a mean and a standard deviation. Substituting the current operating condition parameters into a pre-stored parameter correspondence to obtain the current characteristic curve parameters includes:

[0070] Substitute the current speed and current load into the parameter correspondence to obtain the current mean and current standard deviation.

[0071] It is understood that the parameter correspondence in the embodiment of the present application is determined by placing the vehicle on the test bench in advance and collecting the in-cylinder data of multiple cycles at different speeds and loads. After placing the vehicle on the test bench and collecting the in-cylinder data of multiple cycles at a specific speed and load, through inductive analysis, a probability distribution curve of the ignition angle corresponding to 50% combustion of the fuel in the cylinder at a specific speed and a specific load can be summarized, that is, a characteristic curve. The characteristic curve is as follows: Figure 3 As shown, Figure 3The horizontal axis represents the ignition angle corresponding to 50% fuel combustion in the cylinder, and the vertical axis represents the probability. A cycle refers to the entire cycle of intake, compression, power, and exhaust in a cylinder. For example, if 900 cycles of in-cylinder data are collected, the ignition angle corresponding to 50% fuel combustion (also known as the combustion center) will be more common in the middle of these 900 cycles, and less common at the extreme ends. The probability of the ignition angle corresponding to 50% fuel combustion is generally normally distributed, indicating that the characteristic curve is a normal distribution curve. Since the characteristic curve is a normal distribution curve, its shape is determined by its mean and standard deviation. In other words, the characteristic curve parameters include the mean and standard deviation. Simply determining the mean and standard deviation is sufficient to plot the corresponding characteristic curve. The shape of the corresponding characteristic curve will also vary when the engine is operating under different operating conditions. Therefore, by pre-placing the vehicle on a test bench and collecting in-cylinder data for multiple cycles under different operating conditions, the relationship between the operating condition parameters and the characteristic curve parameters can be determined. The parameter correspondence between operating condition parameters and characteristic curve parameters stores the correspondence between engine speed and load, and the mean and standard deviation of the characteristic curve. This parameter correspondence can be predetermined through a limited number of tests and stored in the vehicle controller's storage medium.

[0072] Since the shapes of the corresponding characteristic curves are different when the engine operates under different working conditions, in step S202, after substituting the current working condition parameters into the pre-stored parameter correspondence, the current characteristic curve parameters corresponding to the current working condition can be obtained.

[0073] In step S203 , a current characteristic curve is obtained according to the current characteristic curve parameters.

[0074] In some optional embodiments, obtaining the current characteristic curve according to the current characteristic curve parameters includes:

[0075] A current characteristic curve is obtained according to the current mean and the current standard deviation. The current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

[0076] It is understandable that the preset number may be, for example, 900, that is, the current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in 900 cycles.

[0077] Since the current characteristic curve represents the characteristic curve under the current operating parameters, it is also a normal distribution curve. Therefore, the shape of the current characteristic curve is determined by the current mean and current standard deviation. In other words, the corresponding current characteristic curve can be obtained by simply determining the current mean and current standard deviation.

[0078] In step S204 , the current characteristic curve is compared with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve.

[0079] In some optional embodiments, before performing the comparison in step S204, a pre-stored standard characteristic curve needs to be obtained. The standard characteristic curve is also a normal distribution curve. The standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles when the engine is in a standard operating state. The standard operating state of the engine means that the engine is operating at a preset speed and a preset load.

[0080] As will be appreciated, as analyzed above, the shape of the corresponding characteristic curve varies when the engine operates under different operating conditions. Therefore, to determine whether the engine's ignition angle needs adjustment, it is necessary to pre-set a standard operating condition for the engine and compare the difference between the current characteristic curve and the standard characteristic curve for the engine under the standard operating condition. A significant difference indicates an inappropriate ignition angle and requires adjustment.

[0081] Specifically, the preset speed may be 2500 rpm, and the preset load may be 21 bar. It is understood that 1 bar = 100 kPa = 10 Newtons per square centimeter (N / cm2). 2 To obtain a standard characteristic curve, the vehicle can be placed on a test bench in advance, and the engine can be operated at a preset speed and preset load, thereby obtaining the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in 900 cycles as the standard characteristic curve, such as Figure 3 As shown, and stored in the storage medium of the vehicle controller.

[0082] It is understandable that in Figure 3 Among the 900 cycles represented by the standard characteristic curve shown, some cycles burn faster, and the ignition angle corresponding to 50% combustion of the fuel in the cylinder is relatively forward, which makes it easy for knocking to occur. The more cycles in which knocking occurs, the thinner the cylinder combustion is, the higher the thermal efficiency is, but the more unstable the combustion is, and the worse the NVH is. Conversely, the fewer cycles in which knocking occurs, the richer the cylinder combustion is, the lower the thermal efficiency is, but the more stable the combustion is, and the better the NVH is. Therefore, it is necessary to find an optimal balance point so that both thermal efficiency and NVH can satisfy users. In some optional embodiments, the preset number of knocking cycles that are allowed to occur can be 30, that is, knocking occurs in a maximum of 30 cycles in 900 cycles, NVH is within an acceptable level, and the thermal efficiency is relatively high. And in Figure 3In the standard characteristic curve shown, the area enclosed by the curve and the horizontal axis, or the integral of the curve within a specific horizontal axis interval, corresponds to the number of cycles within the ignition angle range. Therefore, the balance point between engine thermal efficiency and NVH mentioned above can be calculated based on the preset number of cycles and the integral of the characteristic curve within the horizontal axis interval. For example, since Figure 3 Among the 900 cycles represented by the characteristic curve shown, the cycle on the left burns faster, and the ignition angle corresponding to 50% combustion of the fuel in the cylinder is relatively early, which makes it easy for knocking to occur. The preset number of knock cycles in which knocking can occur is 30. Therefore, based on the preset number of knock cycles being 30, the following equivalent relationship can be obtained: The integral of the standard characteristic curve on the closed interval [0,α] ( Figure 3 The area of ​​the region S) is the same as the preset knock cycle number, where α represents the knock ignition angle, and the preset knock cycle number represents the number of cycles in which the engine is allowed to produce knock in the preset number of cycles. Figure 3 As shown, the above equilibrium point is Figure 3 The K point in the figure has an abscissa of α, α is 22°, and the ordinate is the standard knock probability of 0.05. The K point can also be called the knock critical point.

[0083] In some optional embodiments, comparing the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve includes:

[0084] The knock ignition angle in the standard characteristic curve is substituted into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve.

[0085] Figure 4 An example is given showing a possible relative relationship between the standard characteristic curve and the current characteristic curve, such as Figure 4 As shown, the standard characteristic curve is V0, the knock critical point is point K, and the area prone to knock is area S. In real time, due to the external environment causing the engine to burn slowly, the current load is low, and the current speed is high, the current characteristic curve under the current operating parameters shifts to the right and becomes V1. To determine whether the knock is within the acceptable deviation, the horizontal axis of the standard characteristic curve V0 is set to the knock ignition angle α = 22°

[0086] Substituting this into the current characteristic curve V1 yields point K' corresponding to the knock ignition angle α. The ordinate of point K' represents the current knock probability. For example, the current knock probability corresponding to point K' in the current characteristic curve V1 is 0.01.

[0087] and Figure 4 The situation is different, Figure 5An example shows another possible relative relationship between the standard characteristic curve and the current characteristic curve. The current characteristic curve V2 under the current operating parameters is shifted to the left relative to the standard characteristic curve V0. The method for determining the current knock probability is the same as Figure 4 similar.

[0088] After the current knock probability is obtained, a probability difference between the current knock probability and a standard knock probability is further calculated, wherein the standard knock probability corresponds to the knock ignition angle in the standard characteristic curve.

[0089] It is understandable that for Figure 4 In the case of , calculating the probability difference between the current knock probability 0.01 and the standard knock probability 0.05 refers to calculating the absolute value of the difference between the current knock probability 0.01 and the standard knock probability 0.05, and the final probability difference result is 0.04. Figure 5 and Figure 4 Same thing.

[0090] In step S205 , the ignition angle of the engine is adjusted according to the probability difference.

[0091] In some optional embodiments, adjusting the ignition angle of the engine according to the probability difference includes:

[0092] When the probability difference is less than the preset probability difference, it indicates that the deviation between the current knock probability and the standard knock probability is within the allowable deviation, that is, the current engine ignition angle is close to the optimal ignition angle. The control strategy is to keep the current ignition angle unchanged, thereby reducing the volatility of the ignition angle and improving the combustion stability of the engine.

[0093] When the probability difference is greater than the preset probability difference, the magnitude relationship between the current knock probability and the standard knock probability is determined.

[0094] It is understood that when the probability difference is greater than a preset probability difference, it indicates that the current ignition angle is unreasonable, either too advanced or too delayed, and the ignition angle needs to be adjusted accordingly. In this case, it is necessary to further determine the relationship between the current knock probability and the standard knock probability. In some optional embodiments, the preset probability difference may be 0.01.

[0095] like Figure 4 As shown, the current characteristic curve under the current operating parameters has shifted to the right and becomes V1. The probability difference between the current knock probability of 0.01 and the standard knock probability of 0.05 is 0.04, which is greater than the preset probability difference of 0.01. The current ignition angle of the engine is unreasonable and needs to be adjusted.

[0096] When the current knock probability is less than the standard knock probability, the ignition angle of the engine is advanced by a first preset angle.

[0097] In some alternative embodiments, the ignition angle can be adjusted by rotating the distributor housing. Rotating the distributor housing counterclockwise increases the ignition advance angle, in other words, the ignition angle is relatively advanced. Rotating the distributor housing clockwise decreases the ignition advance angle, in other words, the ignition angle is relatively delayed.

[0098] like Figure 4 As shown, the current characteristic curve under the current operating parameters has shifted to the right, becoming V1. The current knock probability of 0.01 is less than the standard knock probability of 0.05, and the ignition angle is too delayed. In this case, the engine ignition angle needs to be advanced by a first preset angle. The first preset angle can be 5 degrees.

[0099] When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

[0100] and Figure 4 The situations are different, such as Figure 5 As shown, the current characteristic curve V2 under the current operating parameters is shifted to the left relative to the standard characteristic curve V0. The current knock probability is greater than the standard knock probability, and the ignition angle is too advanced. In this case, the engine ignition angle needs to be delayed by a second preset angle. The second preset angle can also be 5°.

[0101] Since the first preset angle and the second preset angle are the same, the stability of the ignition angle control can be improved.

[0102] In some optional embodiments, after the ignition angle adjustment process in step S205 is performed, step S201 may be re-executed to perform a cyclic judgment, so that the ignition angle of the engine is always kept within the optimal range.

[0103] The gasoline engine knock control method provided in the present application does not require the installation of a knock sensor, thereby reducing the control cost. The corresponding current characteristic curve parameters can be directly obtained according to the current operating parameters of the engine, and compared with the pre-stored standard characteristic curve to obtain the probability difference between the current knock probability and the standard knock probability, thereby indirectly determining the engine knock condition and judging whether the ignition angle is reasonable. When the ignition angle is unreasonable, the engine ignition angle can be actively advanced or delayed according to the probability difference. Compared with the technical solution in the prior art that can only delay the ignition angle, more accurate control of engine knock is also achieved, thereby improving the engine thermal efficiency while ensuring the engine NVH.

[0104] The present application also provides a gasoline engine knock control device, such as Figure 6 As shown, the device includes a working condition acquisition module 601, a parameter acquisition module 602, a curve determination module 603, a difference acquisition module 604 and an adjustment module 605, wherein:

[0105] The operating condition acquisition module 601 is configured to obtain current operating condition parameters of the engine.

[0106] The parameter acquisition module 602 is configured to substitute the current operating condition parameters into the pre-stored parameter correspondence relationship to obtain the current characteristic curve parameters. The parameter correspondence relationship includes the correspondence between the operating condition parameters and the characteristic curve parameters.

[0107] The curve determination module 603 is configured to obtain a current characteristic curve according to the current characteristic curve parameters.

[0108] The difference acquisition module 604 is configured to compare the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between the current knock probability in the current characteristic curve and the standard knock probability in the standard characteristic curve.

[0109] The adjustment module 605 is configured to adjust the ignition angle of the engine according to the probability difference.

[0110] In some optional embodiments, the operating condition parameters include the engine speed and load, the characteristic curve parameters include the mean and standard deviation, and the parameter acquisition module 602 is configured to:

[0111] Substitute the current speed and current load into the parameter correspondence to obtain the current mean and current standard deviation.

[0112] Wherein, the current characteristic curve is a normal distribution curve, and the curve determination module 603 is configured as follows:

[0113] A current characteristic curve is obtained according to the current mean and the current standard deviation. The current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

[0114] In some optional embodiments, the difference acquisition module 604 is configured to:

[0115] The knock ignition angle in the standard characteristic curve is substituted into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve.

[0116] A probability difference between the current knock probability and a standard knock probability is calculated, where the standard knock probability corresponds to the knock ignition angle in a standard characteristic curve. The standard characteristic curve is a normal distribution curve. The standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles when the engine is in a standard operating state. The engine being in a standard operating state means that the engine is operating at a preset speed and a preset load.

[0117] In some optional embodiments, the integral of the standard characteristic curve on the closed interval [0, α] is the same as the preset number of knock cycles, where α represents the knock ignition angle, and the preset number of knock cycles represents the number of cycles in which the engine is allowed to produce knock in a preset number of cycles.

[0118] In some optional embodiments, the adjustment module 605 is configured to:

[0119] When the probability difference is greater than the preset probability difference, the magnitude relationship between the current knock probability and the standard knock probability is determined.

[0120] When the current knock probability is less than the standard knock probability, the ignition angle of the engine is advanced by a first preset angle.

[0121] When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

[0122] This embodiment and the method embodiment are based on the same inventive concept and are system embodiments corresponding to the method embodiment. Therefore, those skilled in the art should understand that the description of the method embodiment is also applicable to this embodiment, and some technical details are no longer described in detail in this embodiment.

[0123] The gasoline engine knock control device provided by the present application does not require the installation of a knock sensor, thereby reducing the control cost. The corresponding current characteristic curve parameters can be directly obtained according to the current operating parameters of the engine, and compared with the pre-stored standard characteristic curve to obtain the probability difference between the current knock probability and the standard knock probability, thereby indirectly determining the engine knock condition and judging whether the ignition angle is reasonable. When the ignition angle is unreasonable, the engine ignition angle can be actively advanced or delayed according to the probability difference. Compared with the technical solution in the prior art that can only delay the ignition angle, more accurate control of engine knock is also achieved, thereby improving the engine thermal efficiency while ensuring the engine NVH.

[0124] In this application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0125] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only.

[0126] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0127] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection of this application.

Claims

1. A gasoline engine knock control method, characterized in that: The method comprises: Get the current operating parameters of the engine; Substituting the current operating condition parameters into a pre-stored parameter correspondence relationship to obtain current characteristic curve parameters, wherein the parameter correspondence relationship includes a correspondence relationship between the operating condition parameters and the characteristic curve parameters; obtaining a current characteristic curve according to the current characteristic curve parameters; Comparing the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between a current knock probability in the current characteristic curve and a standard knock probability in the standard characteristic curve; adjusting the ignition angle of the engine according to the probability difference, The operating condition parameters include the engine speed and load, the characteristic curve parameters include the mean and standard deviation, and the current characteristic curve parameters obtained by substituting the current operating condition parameters into the pre-stored parameter correspondence include: Substituting the current speed and the current load into the parameter correspondence to obtain the current mean and the current standard deviation; The current characteristic curve is a normal distribution curve, and obtaining the current characteristic curve according to the current characteristic curve parameters includes: The current characteristic curve is obtained according to the current mean value and the current standard deviation, and the current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

2. The method according to claim 1, characterized in that The comparing the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between a current knock probability in the current characteristic curve and a standard knock probability in the standard characteristic curve includes: Substituting the knock ignition angle in the standard characteristic curve into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve; A probability difference between the current knock probability and the standard knock probability is calculated, wherein the standard knock probability corresponds to the knock ignition angle in the standard characteristic curve, the standard characteristic curve is a normal distribution curve, and the standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in the preset number of cycles when the engine is in a standard operating state, wherein the engine being in a standard operating state means that the engine is operating at a preset speed and a preset load.

3. The method according to claim 2, characterized in that The integral of the standard characteristic curve on the closed interval [0, α] is the same as the preset number of knock cycles, where α represents the knock ignition angle, and the preset number of knock cycles represents the number of cycles in which the engine is allowed to produce knock in the preset number of cycles.

4. The method according to claim 1, wherein The adjusting the ignition angle of the engine according to the probability difference comprises: When the probability difference is greater than a preset probability difference, determining a magnitude relationship between the current knock probability and the standard knock probability; When the current knock probability is less than the standard knock probability, advancing the ignition angle of the engine by a first preset angle; When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

5. A gasoline engine knock control device, characterized in that: The device comprises: A working condition acquisition module is configured to obtain current working condition parameters of the engine; a parameter acquisition module configured to substitute the current operating condition parameters into a pre-stored parameter correspondence relationship to obtain current characteristic curve parameters, wherein the parameter correspondence relationship includes a correspondence relationship between the operating condition parameters and the characteristic curve parameters; a curve determination module, configured to obtain a current characteristic curve according to the current characteristic curve parameters; a difference acquisition module configured to compare the current characteristic curve with a pre-stored standard characteristic curve to obtain a probability difference between a current knock probability in the current characteristic curve and a standard knock probability in the standard characteristic curve; an adjusting module configured to adjust the ignition angle of the engine according to the probability difference, The operating condition parameters include the engine speed and load, the characteristic curve parameters include the mean and standard deviation, and the parameter acquisition module is configured as follows: Substituting the current speed and the current load into the parameter correspondence to obtain the current mean and the current standard deviation; Wherein, the current characteristic curve is a normal distribution curve, and the curve determination module is configured to: The current characteristic curve is obtained according to the current mean value and the current standard deviation, and the current characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in a preset number of cycles.

6. The device according to claim 5, characterized in that The difference acquisition module is configured as follows: Substituting the knock ignition angle in the standard characteristic curve into the current characteristic curve to obtain the current knock probability corresponding to the knock ignition angle in the current characteristic curve; A probability difference between the current knock probability and the standard knock probability is calculated, wherein the standard knock probability corresponds to the knock ignition angle in the standard characteristic curve, the standard characteristic curve is a normal distribution curve, and the standard characteristic curve represents the probability distribution of the ignition angle corresponding to 50% combustion of the cylinder fuel in the preset number of cycles when the engine is in a standard operating state, wherein the engine being in a standard operating state means that the engine is operating at a preset speed and a preset load.

7. The device according to claim 6, characterized in that The integral of the standard characteristic curve on the closed interval [0, α] is the same as the preset number of knock cycles, where α represents the knock ignition angle, and the preset number of knock cycles represents the number of cycles in which the engine is allowed to produce knock in the preset number of cycles.

8. The device according to claim 5, characterized in that The adjustment module is configured to: When the probability difference is greater than a preset probability difference, determining a magnitude relationship between the current knock probability and the standard knock probability; When the current knock probability is less than the standard knock probability, advancing the ignition angle of the engine by a first preset angle; When the current knock probability is greater than the standard knock probability, the ignition angle of the engine is delayed by a second preset angle.

Images