Engine control device and system

Abstract

The invention provides an engine control device and system, and relates to the technical field of engine control. Wherein the fuel oil identification module is used for detecting and judging whether a knocking signal or a fuel oil physical and chemical signal of a current engine meets a preset rule or not in real time and obtaining the real-time working condition of the engine, and the air cylinder pressure adjustment module is used for generating an initial pressure fluctuation coefficient; the knock factor analysis module determines a composite knock factor based on the knock signal and an initial pressure fluctuation coefficient when the knock signal or the fuel physical and chemical signal does not meet a preset rule, so that the ignition angle adjustment module generates a retreat angle / recovery instruction based on the knock level of the knock factor; the cylinder pressure adjustment module then adjusts a mixture air-fuel ratio of the engine cylinder based on the retreat angle / recovery command, and updates the initial pressure fluctuation factor to update the composite knock factor. On the basis, the service life of the engine can be prolonged, and the operation stability of the engine can be improved on the basis of improving the fuel oil adaptability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine control, in particular to an engine control device and system. BACKGROUND

[0002] With the development of globalization, there are many technical problems in the current engine control technology field. For example, the difference between the fuel standards of different countries and regions. The existing technology often judges the threshold value of a single channel vibration signal to detect the abnormal combustion state of unburned mixed gas in the internal combustion engine under high temperature and high pressure environment. However, this single channel detection method not only cannot adapt to complex internal combustion engine working conditions, but also lacks the ability to predict the knocking trend. In addition, since the ignition system and the fuel injection system are independently controlled, when the engine uses fuel lower than the fuel standard, the traditional control strategy will cause continuous knocking due to the lagging adjustment of the ignition angle, thereby seriously affecting the service life and running stability of the engine.

[0003] Therefore, there is an urgent need for an engine control strategy that can improve the knocking suppression effect on the basis of improving the fuel adaptability, so as to avoid the problems that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel anti-knock performance caused by the difference of fuel standards, and the problems that the cylinder pressure fluctuation and the ignition timing adjustment cannot form a synergistic effect. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide an engine control device and system to improve the fuel adaptability, avoid the problem that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel anti-knock performance caused by the difference of fuel standards, and make the cylinder pressure fluctuation and the ignition timing adjustment form a synergistic effect, thereby improving the service life and running stability of the engine. In a first aspect, the present application provides an engine control device applied to an engine system, the engine system at least comprising an engine, and the engine control device is used to improve the knocking effect of the engine; the engine control device comprises: a fuel identification module, a knocking factor analysis module, an ignition angle adjustment module, and a cylinder pressure adjustment module; The fuel identification module is used to detect and judge whether the knocking signal and the fuel physicochemical signal of the engine satisfy a preset rule in real time, and to obtain the real-time working condition of the engine; wherein the preset threshold under the preset rule is determined according to the real-time working condition of the engine; The cylinder pressure adjustment module is used to generate an initial pressure fluctuation coefficient; The knocking factor analysis module is used to determine a composite knocking factor based on the knocking signal and the initial pressure fluctuation coefficient when the knocking signal or the fuel physicochemical signal does not satisfy the preset rule; The ignition angle adjustment module is used to obtain and generate a retreat angle / restoration instruction based on the knocking factor; The cylinder pressure adjustment module is configured to adjust a mixture air-fuel ratio of the engine cylinder based on the corner / return instruction, and update the initial pressure fluctuation coefficient to update the compound knock factor.

[0005] In a possible implementation, when the preset threshold value includes a knock threshold value and a preset dielectric threshold value, and the fuel physical and chemical signal includes a fuel dielectric constant, the fuel identification module includes a knock detection unit, a fuel detection unit, a threshold determination unit, and a signal triggering unit; The knock detection unit is configured to detect a knock signal of the engine and an engine temperature in real time, and determine whether the engine temperature exceeds a preset temperature value. The fuel detection unit is configured to detect a fuel dielectric constant of the engine in real time, and determine whether the fuel dielectric constant exceeds a preset dielectric threshold value. The threshold determination unit is configured to calculate a dynamic threshold value corresponding to the current engine based on a real-time working condition of the engine according to a Kalman filtering method, as the knock threshold value, and determine whether the knock signal exceeds the knock threshold value. The signal triggering unit is further configured to send a first trigger signal to the knock factor analysis module to make the knock factor analysis module perform knock analysis when the fuel dielectric constant exceeds the preset dielectric threshold value. And / or the signal triggering unit is further configured to send a first trigger signal to the knock factor analysis module when the knock signal exceeds the knock threshold value and the engine temperature exceeds the preset temperature value.

[0006] In a possible implementation, the knock factor analysis module includes a first counting unit, a second counting unit, and a weighted fusion module. The first counting unit is configured to obtain and count a knock ratio of the engine in any sampling interval, and determine a basic knock factor according to the knock ratio; the knock ratio is used to represent a ratio between a total number of knock cycles and a total number of cycles of the current engine in any sampling interval; and an upper limit of the total number of cycles is determined by the pressure fluctuation coefficient. The second counting unit is configured to obtain a frequency band energy proportion and a combustion phase shift of the engine in any sampling interval. The weighted fusion module is configured to perform weighted calculation on the frequency band energy proportion, the combustion phase shift, and the basic knock factor to obtain a compound knock factor, and determine a knock level of the knock factor according to a preset level division rule and send a second trigger signal to the ignition angle adjustment module if the compound knock factor exceeds a first safety threshold value.

[0007] In a possible implementation, a calculation formula of the compound knock factor is as follows: ; Wherein, is the compound knock factor. is a base knock factor; is a frequency band energy proportion; is a combustion phase offset, a is a first weighting coefficient, the value satisfying 0.5; b is a second weighting coefficient, the value satisfying 0.3; c is a third weighting coefficient, the value satisfying 0.2.

[0008] In a possible implementation, when the real-time working condition includes a load state, the engine system at least includes an ignition module, and an output end of the ignition angle adjustment module is connected to the ignition module through a bus; the ignition module is also connected to the engine; The ignition angle adjustment module is also configured to, after receiving the second trigger signal, determine an ignition retardation instruction of the ignition module based on the knock level of the knock factor and the load state, so as to adjust a retardation amplitude of the engine.

[0009] In a possible implementation, the weighted fusion module is also configured to determine whether the composite knock factor exceeds a second safety threshold and is less than a first safety threshold, and if so, send a third trigger signal to the ignition angle adjustment module; The ignition angle adjustment module is also configured to, after receiving the third trigger signal, adjust the ignition angle of the engine to a preset angle.

[0010] In a possible implementation, the ignition angle adjustment module is also configured to determine a knock frequency characteristic value based on the frequency band energy proportion, and adjust a recovery speed of the ignition angle of the engine through the knock frequency characteristic value, so as to avoid knock rebound in the ignition angle recovery process; wherein a calculation formula of the ignition angle recovery speed is as follows: ; In the formula, α is the ignition angle recovery speed; is the ignition angle recovery speed; is a current ignition angle speed; is an ignition angle recovery step; is the knock frequency characteristic value.

[0011] In a possible implementation, the cylinder pressure adjustment module is configured to update a pressure fluctuation coefficient according to the frequency band energy proportion and the working condition parameter of the engine by using a least square method, so that a cylinder pressure fluctuation range is lower than a preset standard deviation; wherein a forgetting factor of the least square method is 0.98; The knock factor analysis module is also configured to receive and adjust an upper limit of the first counting unit according to the updated pressure fluctuation coefficient, so as to update the base knock factor; The cylinder pressure adjustment module is also configured to detect, in real time, an intake temperature of a cylinder in the current engine; The cylinder pressure adjustment module is further configured to adjust the fuel enrichment concentration according to the intake temperature, the knock level of the knock factor and the real-time working condition of the engine, so as to improve the air-fuel ratio of the mixture in the cylinder; wherein the intake temperature is related to the ignition angle of the engine.

[0012] In a possible implementation manner, the real-time working condition of the engine at least includes a rotating speed, a throttle opening degree and a turbocharging pressure. The cylinder pressure adjustment module is further configured to determine a basic enrichment amount according to the rotating speed, the throttle opening degree and the turbocharging pressure. The cylinder pressure adjustment module is further configured to adjust an enrichment amplitude according to the knock level of the knock factor, and obtain a final fuel enrichment concentration based on the basic enrichment amount and the enrichment amplitude.

[0013] In a second aspect, the application further provides an engine system, which comprises an engine and the engine control device of any one of the first aspect, and the engine control device is connected with the engine and used for improving the knock effect of the engine.

[0014] The engine control device and system provided by the application have the following beneficial effects: The engine control device constructs a four-dimensional coupling architecture, which comprises a fuel identification module, a knock factor analysis module, an ignition angle adjustment module and a cylinder pressure adjustment module. The fuel identification module is used for detecting and judging whether the knock signal or the fuel physical and chemical signal of the current engine meets a preset rule in real time, and obtaining the real-time working condition of the engine. The cylinder pressure adjustment module is used for generating an initial pressure fluctuation coefficient. The knock factor analysis module is used for determining a composite knock factor based on the knock signal and the initial pressure fluctuation coefficient when the knock signal or the fuel physical and chemical signal does not meet the preset rule, so that the ignition angle adjustment module generates a retreat angle / restoration instruction based on the knock level of the knock factor. Finally, the cylinder pressure adjustment module adjusts the air-fuel ratio of the mixture in the cylinder based on the retreat angle / restoration instruction, and updates the initial pressure fluctuation coefficient to update the composite knock factor. Based on this, the application realizes the multi-system linkage of fuel-ignition-pressure through the above four-dimensional coupling architecture, can avoid the problem that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel anti-knock performance caused by the difference in fuel standard on the basis of improving the fuel adaptability, and makes the cylinder pressure fluctuation and the ignition timing adjustment form a synergistic effect, thereby improving the service life and the running stability of the engine. BRIEF DESCRIPTION OF DRAWINGS In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments of the application. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those skilled in the art without creative labor.

[0015] Figure 1 Structure diagram of an engine system provided in an embodiment of the present application; Figure 2 Structure diagram of an engine control device provided in an embodiment of the present application; Figure 3 Structure diagram of a fuel identification module provided in an embodiment of the present application; Figure 4 Structure diagram of a knock factor analysis module provided in an embodiment of the present application; Figure 5 Structure diagram of an engine control device provided in an embodiment of the present application.

[0016] Icon: 10-engine system; 100-engine control device; 200-engine; 300-ignition module; 101-fuel identification module; 102-knock factor analysis module; 103-ignition angle adjustment module; 104-cylinder pressure adjustment module; 201-knock detection unit; 202-fuel detection unit; 203-threshold determination unit; 204-signal triggering unit; 205-first counting unit; 206-second counting unit; 207-weighted fusion module. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0018] To avoid the problem that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel knock resistance due to the difference in fuel standards and the problem that the cylinder pressure fluctuation and the ignition timing adjustment cannot form a synergistic effect, please refer to Figure 1 , Figure 1 Structure diagram of an engine system provided in an embodiment of the present application, the engine system 10 in the embodiment includes an engine 200 and an engine control device 100, the engine control device 100 is connected with the engine 200, and the engine control device 100 is used to improve the knock effect of the engine 200.

[0019] The engine control device in the embodiment breaks the limitation of traditional independent control of the system, realizes the synergistic optimization of each key parameter through a complex knock factor by constructing a nonlinear coupling model of fuel characteristics-knock characteristics-ignition timing-cylinder pressure, and improves the response speed of the engine system by 60% based on the linkage of multiple key parameters.

[0020] The same idea as the previous embodiment, please refer to Figure 1 on the basis of Figure 2 , Figure 2A structure diagram of an engine control device provided by the embodiment of the present application is shown in the figure, and the engine control device 100 comprises: a fuel identification module 101, a knock factor analysis module 102, an ignition angle adjustment module 103, and a cylinder pressure adjustment module 104.

[0021] The fuel identification module 101 is connected with the knock factor analysis module 102, the ignition angle adjustment module 103 is further connected with the knock factor analysis module 102 and the cylinder pressure adjustment module 104, and the cylinder pressure adjustment module 104 is further connected with the knock factor analysis module 102.

[0022] The fuel identification module 101 in the embodiment is used to detect and judge whether the knock signal and the fuel physicochemical signal of the engine meet the preset rule in real time, and to obtain the real-time working condition of the engine.

[0023] The preset threshold under the preset rule is determined according to the real-time working condition of the engine.

[0024] The cylinder pressure adjustment module 104 is used to generate an initial pressure fluctuation coefficient.

[0025] The knock factor analysis module 102 is used to determine a composite knock factor based on the knock signal and the initial pressure fluctuation coefficient when the knock signal or the fuel physicochemical signal does not meet the preset rule.

[0026] The ignition angle adjustment module 103 is used to obtain and generate a retreat angle / restoration instruction based on the knock signal.

[0027] The cylinder pressure adjustment module 104 is used to adjust the air-fuel ratio of the mixed gas of the cylinder of the engine based on the retreat angle / restoration instruction, and to update the initial pressure fluctuation coefficient to update the composite knock factor, until the fuel identification module does not detect the knock signal in a preset number of sampling periods.

[0028] In the embodiment, the fuel physicochemical signal can be obtained by a micro-capacitance fuel sensor, and then a quality evaluation result is output every 3,000 milliseconds to provide timely fuel information for the system. The micro-capacitance fuel sensor is used to obtain the physicochemical signal of the fuel in the engine, including but not limited to the dielectric constant and conductivity of the fuel. Correspondingly, the knock signal can be obtained by a piezoelectric knock sensor.

[0029] In the embodiment, the real-time working condition includes but is not limited to the speed and load of the engine, and also includes the data obtained by the crankshaft position / throttle opening sensor.

[0030] It should be noted that the retreat angle / restoration instruction in the embodiment includes a retreat angle instruction and a restoration instruction. The retreat angle instruction can be used to improve the retreat angle amplitude of the engine, and the restoration instruction can be used to improve the ignition angle of the engine, thereby improving or suppressing the knock phenomenon of the engine.

[0031] Based on this, the application constructs an engine control device including a fuel identification module, a cylinder pressure adjustment module, a knock factor analysis module, and an ignition angle adjustment module, and then utilizes the modules of the engine control device to cooperate, that is, the engine control device in the application establishes a nonlinear coupling model of fuel characteristics-knock characteristics-ignition timing-cylinder pressure. Based on the linkage relationship of the above-mentioned multi-module parameters, the application can improve the knock suppression effect on the basis of improving the fuel adaptability, and then avoid the problems that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel anti-knock performance due to the difference of fuel standard and the problem that the cylinder pressure fluctuation and the ignition timing adjustment cannot form a synergistic effect.

[0032] In this embodiment, when the preset threshold value includes a knock threshold value and a preset dielectric threshold value, and the fuel physical and chemical signal includes a fuel dielectric constant, please refer to Figure 3 , Figure 3 The structure diagram of the fuel identification module provided by the embodiment of the application is shown in the figure. The fuel identification module 101 includes a knock detection unit 201, a fuel detection unit 202, a threshold determination unit 203, and a signal triggering unit 204. The knock detection unit 201 and the fuel detection unit 202 are connected with the threshold determination unit 203, and the threshold determination unit 203 and the knock detection unit 201 are also connected with the signal triggering unit 204.

[0033] The knock detection unit 201 is used for real-time detection of the knock signal and the engine temperature of the engine, and judges whether the engine temperature exceeds a preset temperature value.

[0034] The fuel detection unit 202 is used for real-time detection of the fuel dielectric constant of the engine, and judges whether the fuel dielectric constant exceeds a preset dielectric threshold value.

[0035] The threshold determination unit 203 is used for calculating the dynamic threshold value corresponding to the current engine based on the Kalman filtering method according to the real-time working condition of the engine as the knock threshold value, and judges whether the knock signal exceeds the knock threshold value.

[0036] The signal triggering unit 204 is also used for sending a first trigger signal to the knock factor analysis module when the fuel dielectric constant exceeds the preset dielectric threshold value, so that the knock factor analysis module performs knock analysis.

[0037] And / or the signal triggering unit 204 is also used for sending a first trigger signal to the knock factor analysis module when the knock signal exceeds the knock threshold value and the temperature exceeds the preset temperature value.

[0038] The knock signal in the embodiment can be acquired by a knock sensor. The knock signal represents that the unburned mixture self-ignites in a high-temperature and high-pressure environment, and an impact wave generated by the self-ignition hits the combustion chamber wall at a speed of 300-1000 m / s, forming a detectable high-frequency vibration signal.

[0039] In a possible implementation manner, the calculation logic of the fuel dielectric constant in the embodiment can be as follows: The fuel identification coefficient kdzwk_w [x] can be accumulated or decremented according to the numerical value and duration of the average retreat angle after the knock occurs, where x represents different speed and load intervals. In a possible implementation manner, the initial value of kdzwk_w can be set as 0, and after being activated, the value is adjusted by a step DZWKINC (increase) or DZWKDEC (decrease) at a calculation period of about 100 milliseconds, and the value range is limited to 0-1, thereby determining the fuel dielectric constant.

[0040] The knock effect of the engine is evaluated by the high-frequency vibration signal in the embodiment, and a multi-stage response model is constructed, that is, the knock signal, the temperature of the engine, and the fuel dielectric constant of the engine are acquired and detected first, then the dynamic threshold corresponding to the current engine, that is, the knock threshold, is calculated by acquiring the real-time working condition of the engine, and the knock factor analysis module is further triggered only when the knock signal exceeds the knock threshold, and the temperature exceeds the preset temperature value or the fuel dielectric constant exceeds the preset dielectric threshold.

[0041] Based on this, the knock prediction-dynamic response closed-loop control system is constructed in the embodiment, and only when the high-frequency vibration signal and the fuel physicochemical parameter jointly trigger the early warning (for example, the fuel dielectric constant is abnormal or the high-frequency component of the cylinder pressure is excessive), the joint adjustment of the next-stage knock factor analysis module, the ignition angle adjustment module, and the cylinder pressure adjustment module and the like is triggered.

[0042] Please continue to refer to Figure 3 The threshold determination unit 203 in the embodiment is also configured to calculate the dynamic threshold corresponding to the current engine as the knock threshold by using a Kalman filtering method based on the speed and load state.

[0043] The calculation formula of the dynamic threshold corresponding to the current engine satisfies: ; In the formula, Z is the dynamic threshold; N is the speed of the current engine; L is the load of the current engine.

[0044] ​The embodiment updates the model parameters in real time through the Kalman filtering algorithm, that is, the dynamic threshold corresponding to the current engine, and then dynamically adjusts the detection threshold of the knock signal according to the rapid change of the engine working condition, thereby effectively avoiding misjudgment caused by working condition fluctuations, and the inventor's experimental research shows that the above-mentioned method can reduce the misjudgment rate to 3.7% under the condition of rapid acceleration.

[0045] Please refer to Figure 4 , Figure 4 The structure diagram of the knock factor analysis module provided by the embodiment is shown in the figure, and the knock factor analysis module 102 includes a first counting unit 205, a second counting unit 206 and a weighted fusion module 207. The first counting unit 205 and the second counting unit 206 are connected with the weighted fusion module 207.

[0046] The first counting unit 205 is used to acquire and count the knock ratio of the engine in any sampling interval, and to determine the basic knock factor according to the knock ratio. The knock ratio is used to represent the ratio between the total number of knock cycles and the total number of cycles of the current engine in any sampling interval.

[0047] The upper limit of the total number of cycles is determined by the pressure fluctuation coefficient.

[0048] The second counting unit 206 is used to acquire the frequency band energy proportion and the combustion phase offset of the engine in any sampling interval.

[0049] The weighted fusion module 207 is used to perform weighted calculation on the frequency band energy proportion, the combustion phase offset and the basic knock factor to obtain a composite knock factor, and to determine the knock grade of the knock factor according to the preset grade division rule if the composite knock factor exceeds the first safety threshold, and to send a second trigger signal to the ignition angle adjustment module 103.

[0050] The embodiment sets the composite knock factor based on the dynamic counter optimization mechanism. It should be noted that the upper limit of the first counting unit is related to the pressure ratio coefficient in the cylinder pressure adjustment module, and thus the amplitude of the cylinder pressure fluctuation can be controlled under the ignition retardation condition, and the intermittent knock recognition accuracy can be improved. The second counting unit adopts a hierarchical accumulation strategy, that is, the intensity of the knock signal is partitioned, for example, when the intensity of the knock signal is >1.5V, 2 is accumulated, 1.0-1.5V is accumulated, and <1.0V is not accumulated, thereby improving the accuracy of distinguishing the intensity of the knock signal. That is, the first counting unit in the embodiment is used to determine the basic knock factor in the composite knock factor, and the second counting unit 206 adjusts the basic knock factor in a small amount, that is, determines the accumulation coefficient based on the frequency band energy proportion and the combustion phase offset, and thus through this dynamic adjustment mechanism, different intensity knock signals can be captured more sensitively, and more accurate basis can be provided for subsequent control.

[0051] The calculation formula of the composite knock factor in the embodiment is represented as: ; Wherein, is the composite knock factor; is the base knock factor; is the frequency band energy ratio; is the combustion phase offset, a is the first weighting coefficient, the value satisfies 0.5; b is the second weighting coefficient, the value satisfies 0.3; c is the third weighting coefficient, the value satisfies 0.2.

[0052] In the formula, the frequency band energy ratio is the 20-60 kHz frequency band energy ratio, which can be obtained by analyzing the 20-60 kHz high frequency band through short-time Fourier transform (STFT) on the original vibration signal (16 kHz sampling rate) obtained by the knock sensor. The frequency band covers the shock wave frequency range generated by knock, and the energy ratio change directly reflects the knock intensity, providing frequency domain feature support for the composite knock factor.

[0053] Wherein, the combustion phase offset refers to the difference between the measured combustion phase and the ideal phase, which can be calculated in real time by the cylinder pressure sensor (accuracy ±0.5% FS).

[0054] Based on this, the construction model of the composite knock factor in the embodiment comprehensively considers the occurrence probability, frequency characteristics and combustion phase offset of knock, and can more accurately evaluate the knock risk.

[0055] In one possible implementation manner, the composite knock factor can be divided into three levels, the first level: safe state, in which the value of the composite knock factor is less than 0.7; the second level: moderate knock state, in which the value of the composite knock factor is more than 0.7 but less than 0.9; the third level: strong knock state, in which the value of the composite knock factor is more than 0.9.

[0056] Please refer to Figure 5 , Figure 5 another structural schematic diagram of the engine control device provided by the embodiment of the application, when the real-time working condition includes the load state, the engine system at least includes the ignition module 300, the output end of the ignition angle adjustment module 103 is connected with the ignition module 300 through a bus; the ignition module 300 is also connected with the engine 200.

[0057] The ignition angle adjustment module 103 is further configured to determine the ignition retardation instruction of the ignition module 300 based on the knock level of the knock factor and the load state after receiving the second trigger signal, so as to adjust the retardation amplitude of the engine 200.

[0058] In one possible implementation, the corresponding relationship between the ignition retardation instruction of the ignition module 300 and the knock level of the knock factor and the load state can be shown in the following table:

[0059] In the embodiment, when the composite knock factor is greater than 0.7 but less than 0.8, the knock level at this time can be defined as light; when the composite knock factor is greater than 0.8 but less than 0.915, the knock level at this time can be defined as moderate; and when the composite knock factor is greater than 0.9.15, the knock level at this time can be defined as severe. Correspondingly, when the load ratio is less than 50%, the load state can be defined as low load; when the load ratio is between 50% and 80%, the load state can be defined as medium load; and when the load ratio is greater than 80%, the load state can be defined as high load.

[0060] Based on this, when the knock level is light and the load state is low load, the ignition retardation can be set to 3° at this time; when the knock level is moderate and the load state is medium load, the ignition retardation can be set to 4°-6° at this time; and when the knock level is severe and the load state is high load, the ignition retardation can be set to 3°-5° at this time.

[0061] Further, to further reduce the risk of knock, the weighting fusion module 207 is further configured to determine whether the composite knock factor is greater than the second safety threshold and less than the first safety threshold, and if so, send a third trigger signal to the ignition angle adjustment module 103.

[0062] The ignition angle adjustment module 103 is further configured to adjust the ignition angle of the engine 200 to a preset angle after receiving the third trigger signal.

[0063] In the embodiment, the first safety threshold can be 0.7, and the second safety threshold can be 0.6. When the composite knock factor is greater than 0.6 but less than 0.7, the ignition angle adjustment module can adjust the ignition angle in advance to take measures to reduce the risk, for example, the interval value of the ignition angle of the engine is a preset value, for example, 1°.

[0064] ​​To avoid the risk of knocking, when a strong knocking risk is triggered, the above-mentioned ignition angle setting is quickly completed in this embodiment, for example, the ignition retard angle can be completed within 100 milliseconds. Meanwhile, in this embodiment, the cylinder pressure adjustment module is configured to obtain and adjust the fuel enrichment concentration of the engine or the opening degree of the exhaust gas recirculation valve based on the knocking level corresponding to the knocking factor, so as to suppress the knocking phenomenon of the engine.

[0065] Further, in this embodiment, when the knocking level is slight and the load is low, in addition to setting the ignition retard angle to 3°, the opening degree of the exhaust gas recirculation valve can also be increased by 10% to suppress the cylinder temperature; when the knocking level is moderate and the load is medium, in addition to setting the ignition retard angle to 4°-6°, the fuel enrichment concentration can also be adjusted, for example, the fuel injection amount is enriched by 4-5%, so as to reduce the combustion rate; when the knocking level is severe and the load is high, in addition to setting the ignition retard angle to 3°-5°, the opening degree adjustment and supercharging limitation can also be performed at the same time to quickly suppress the knocking and avoid the occurrence of super-knocking, thereby protecting the engine.

[0066] It should be noted that the threshold between the setting of the knocking level and the setting of the load level in this embodiment can be adjusted according to the actual situation of the user, and this embodiment does not limit the specific value. The above-mentioned implementation manner is only one possible implementation manner.

[0067] In addition, after the above-mentioned retard angle adjustment, if there is no continuous knocking within a preset time period, a variable step recovery strategy can also be adopted to adaptively adjust the ignition angle recovery speed, so as to ensure the smooth transition of the engine to the optimal state.

[0068] In this embodiment, the ignition angle adjustment module 103 is also configured to determine a knocking frequency characteristic value based on the frequency band energy proportion, and adjust the ignition angle recovery speed of the engine through the knocking frequency characteristic value, so as to avoid the rebound of knocking in the ignition angle recovery process.

[0069] The calculation formula of the ignition angle recovery speed is as follows: ; In the formula, v is the ignition angle recovery speed; is the current ignition angle speed; is the ignition angle recovery step; is the knocking frequency characteristic value. Based on this, this embodiment can dynamically adjust the step according to the historical knocking intensity, thereby avoiding the rebound of knocking in the recovery process.

[0070]

[0071] ​The cylinder pressure adjustment module 104 in the embodiment is configured to update the pressure fluctuation coefficient according to the frequency band energy proportion and the working condition parameter of the engine by using the least square method, so that the cylinder pressure fluctuation range is lower than the preset standard deviation; wherein the forgetting factor of the least square method is 0.98.

[0072] The knock factor analysis module 102 is further configured to receive and adjust the upper limit of the first counting unit according to the updated pressure fluctuation coefficient, so as to update the basic knock factor.

[0073] The cylinder pressure adjustment module 104 is further configured to detect the intake temperature of the cylinder in the current engine in real time.

[0074] The cylinder pressure adjustment module 104 is further configured to adjust the fuel enrichment concentration according to the intake temperature, the knock level of the knock factor and the real-time working condition of the engine, so as to improve the air-fuel ratio of the mixed gas in the cylinder.

[0075] The intake temperature is associated with the ignition angle of the engine.

[0076] In the embodiment, the cylinder pressure adjustment module can obtain parameters such as the frequency band energy proportion from the knock factor analysis module to adjust the pressure fluctuation coefficient, and improve the upper limit of the first counting unit through the updated pressure fluctuation coefficient, so as to adjust the basic knock factor.

[0077] The update algorithm of the pressure fluctuation coefficient in the embodiment can be expressed as: ; Wherein, is the remaining time value, is the initial time value; is the actual pressure deviation of the mixed gas; is the turbocharged pressure deviation; is the time correction coefficient; is the pressure fluctuation coefficient; is the correction function based on the throttle pressure ratio.

[0078] The above-mentioned cooperative adjustment mode can make the cylinder pressure fluctuation range reduced to ±3.5%, and improve the combustion stability. At the same time, the embodiment can also adapt to the pressure fluctuation under different working conditions through continuous learning and optimization according to the above-mentioned update algorithm, especially under extreme working conditions such as highlands and extremely cold conditions, to ensure that the cylinder pressure is stable within a reasonable range.

[0079] ​In addition, excessive delay of ignition angle (retard angle) in high load conditions of the engine can also cause the exhaust temperature to rise significantly, thereby increasing the intake temperature through heat transfer, and increasing the risk of early combustion and knocking in the cylinder. To suppress this risk, fuel enrichment control needs to be implemented based on the real-time monitored intake temperature, and the enrichment concentration needs to be optimized through the coordinated modification of load and speed.

[0080] The real-time working condition of the engine in the embodiment also includes the speed, the throttle opening, and the turbocharging pressure.

[0081] Based on this, the cylinder pressure adjustment module 104 is also configured to determine the basic enrichment amount according to the intake temperature and the speed, the throttle opening, and the turbocharging pressure.

[0082] The cylinder pressure adjustment module 104 is also configured to adjust the enrichment amplitude according to the knocking level of the knocking factor, and obtain the final fuel enrichment concentration based on the basic enrichment amount and the enrichment amplitude.

[0083] The essence of the enrichment control in the embodiment is to reduce the temperature of the combustion chamber by increasing the fuel injection amount to reduce the air-fuel ratio of the mixture (i.e., to reduce the excess air coefficient λ) and using the evaporation heat absorption effect of the fuel.

[0084] In the embodiment, the basic air-fuel ratio can be set as the theoretical value, but needs to be actively deviated from the theoretical value in high-temperature conditions. That is, when the intake temperature exceeds the threshold value, the cylinder pressure adjustment module can look up the preset “temperature-enrichment coefficient” mapping table according to the intake temperature and the speed, the throttle opening, and the turbocharging pressure, increase the fuel injection pulse width based on the theoretical value, reduce the actual air-fuel ratio to the enrichment interval of 12.5:1–13.5:1, and obtain the basic enrichment amount, so as to suppress the knocking and protect the high-temperature components.

[0085] In an implementation manner, taking the load modification as an example, since the in-cylinder pressure and temperature rise simultaneously under high load, the enrichment amplitude needs to be significantly increased. For example, when the load rate > 85%, the enrichment coefficient is increased by 15%–20% compared with the medium load, so as to offset the inducing effect of heat load on early combustion.

[0086] Taking the speed modification as an example, the low-speed high-load working condition (such as < 2500 rpm) needs to be additionally superimposed with 5%–10% of enrichment compensation due to low heat dissipation efficiency; the high-speed working condition (> 4500 rpm) can moderately reduce the enrichment amount due to the enhanced airflow.

[0087] Taking the intake temperature correction as an example, when the intake temperature is in the low-temperature zone, that is, the intake temperature < 35℃, the embodiment can maintain the basic air-fuel ratio without enrichment; when the intake temperature is in the medium-temperature zone, that is, the intake temperature is 35℃-60℃, the embodiment can linearly increase the enrichment coefficient, for example, 2%-3% enrichment per 10℃ rise; when the intake temperature is in the high-temperature zone, that is, the intake temperature exceeds 60℃, the embodiment can enable the stepwise enrichment strategy, for example, 4%-5% enrichment per 5℃ rise, and link the intercooler cooling request.

[0088] After obtaining the basic enrichment amount, the embodiment can also adjust the enrichment amplitude according to the knock level of the knock factor, for example, if the knock frequency exceeds the standard, an additional dynamic enrichment compensation Δλ can be added, that is, the enrichment amplitude, and the range of the enrichment compensation Δλ can satisfy 0.1-0.15; and then the final fuel enrichment concentration is obtained based on the basic enrichment amount and the enrichment amplitude, so as to adapt to the sudden change of the working condition based on the double-layer architecture of the feedforward lookup table and the feedback correction, and reduce the risk of in-cylinder early combustion and knock.

[0089] Based on this, the application also provides an experimental verification instruction, that is, verifying the engine using the above-mentioned engine control device, the engine can adapt to fuel with an octane number fluctuation of ±12%, so that the engine can maintain good performance under different fuel qualities and reduce the use cost. At the same time, the strong knock frequency of the engine system is reduced by 47.6%, the piston top temperature is reduced by 80℃, and the engine overhaul period is extended by 35%, which can effectively protect the key parts of the engine and reduce the maintenance frequency and cost. In addition, the thermal efficiency is improved by 3.8%, the torque fluctuation amplitude is reduced from ±12% to ±4.2%, the acceleration time from 0 to 100km / h is shortened by 400 milliseconds. The power performance and driving comfort of the engine are improved.

[0090] In summary, the application constructs a nonlinear coupling model of fuel-knock-ignition-pressure through the above-mentioned four-dimensional coupling architecture, and realizes the linkage of multiple system parameters through the composite knock factor, so that the response speed is improved by 60%, and then on the basis of improving the fuel adaptability, the limitation of traditional independent control of each system is broken, and the collaborative optimization of each key parameter is realized, especially the synergistic effect of cylinder pressure fluctuation and ignition timing adjustment, which improves the service life and running stability of the engine.

[0091] At the same time, the application also combines Kalman filtering, recursive least squares and variable step control strategy, so that the engine control device can still maintain control accuracy in extreme conditions such as high altitude and extreme cold.

[0092] In addition, the application also constructs a three-level response mechanism of "monitoring-early warning-control" through the cooperative work of various algorithms to cope with various working conditions, and cooperatively adjusts according to the corresponding working conditions, avoids the problem that the traditional fixed ignition angle control strategy cannot dynamically adapt to the change of fuel anti-knockness caused by the difference of fuel standards, so that the engine control device in the application can adaptively cope with complex and variable working conditions.

[0093] In the embodiments provided in the application, it should be understood that the disclosed device and method can be implemented in other manners. The described device embodiments are only schematic. For example, the division of the units is only a logical function division. There can be another division manner for the 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. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0094] In addition, the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments of the present application.

[0095] In addition, the functional modules in each embodiment of the application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0096] It should be noted that if the function is realized in the form of a software function module and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0097] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0098] The above description is merely illustrative of the application and not in limitation of the principles of the application. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the application as defined in the following claims.

Claims

1. An engine control device, applied to an engine system, wherein the engine system comprises at least an engine, and the engine control device is used to improve the knock effect of the engine; characterized in that: The engine control device includes: a fuel identification module, a knock factor analysis module, an ignition angle adjustment module and a cylinder pressure adjustment module; The fuel identification module is used to detect and determine in real time whether the knock signal and fuel physical and chemical signals of the engine meet preset rules; and obtain the real-time operating conditions of the engine; wherein the preset threshold value under the preset rules is determined according to the real-time operating conditions of the engine; The cylinder pressure adjustment module is used to generate an initial pressure fluctuation coefficient; The knock factor analysis module is configured to determine a composite knock factor based on the knock signal and the initial pressure fluctuation coefficient when the knock signal or the fuel physical and chemical signal does not satisfy a preset rule; The ignition angle adjustment module is configured to obtain and generate a retreat / recovery instruction based on the knock factor; The cylinder pressure adjustment module is used to adjust the air-fuel ratio of the mixture in the engine cylinder based on the retreat / recovery instruction, and update the initial pressure fluctuation coefficient to update the composite knock factor.

2. The engine control device according to claim 1, characterized in that: When the preset threshold value includes a knock threshold value and a preset dielectric threshold value, and the fuel physical and chemical signal includes a fuel dielectric constant, the fuel identification module includes a knock detection unit, a fuel detection unit, a threshold determination unit, and a signal triggering unit; The knock detection unit is used to detect the knock signal and engine temperature of the engine in real time; and to determine whether the engine temperature exceeds a preset temperature value; The fuel detection unit is used to detect the dielectric constant of the fuel of the engine in real time and determine whether the dielectric constant of the fuel exceeds a preset dielectric threshold; The threshold determination unit is configured to calculate a dynamic threshold corresponding to the current engine according to the real-time operating condition of the engine using a Kalman filter method as a knock threshold; and determine whether the knock signal exceeds the knock threshold; The signal triggering unit is further configured to send a first triggering signal to the knock factor analysis module when the dielectric constant of the fuel exceeds a preset dielectric threshold, so as to enable the knock factor analysis module to perform knock analysis; And / or the signal triggering unit is further configured to send a first triggering signal to the knock factor analysis module when the knock signal exceeds the knock threshold and the temperature exceeds a preset temperature value.

3. The engine control device according to claim 1, characterized in that: The knock factor analysis module includes a first counting unit, a second counting unit, and a weighted fusion module; The first counting unit is configured to obtain and count the knock ratio of the engine in any sampling interval, and determine a basic knock factor according to the knock ratio; The knock ratio is used to represent the ratio between the total number of cycles in which knock occurs in the current engine in any sampling interval and the total number of cycles; wherein the upper limit of the total number of cycles is determined by the pressure fluctuation coefficient; The second counting unit is used to obtain the frequency band energy proportion and combustion phase offset of the engine in any sampling interval; The weighted fusion module is used to perform weighted calculation on the frequency band energy proportion, the combustion phase offset and the basic knock factor to obtain the composite knock factor; and to determine whether the composite knock factor exceeds a first safety threshold. If so, the knock level of the knock factor is determined according to a preset level classification rule, and a second trigger signal is sent to the ignition angle adjustment module.

4. The engine control device according to claim 3, characterized in that: The calculation formula of the composite detonation factor is expressed as: ； in, is the composite detonation factor; is the basic detonation factor; is the energy ratio of the frequency band; is the combustion phase offset, a is the first weighting coefficient, the value of which satisfies 0.5; b is the second weighting coefficient, the value of which satisfies 0.3; c is the third weighting coefficient, the value of which satisfies 0.

2.

5. The engine control device according to claim 3, characterized in that: When the real-time operating condition includes a load state, the engine system includes at least an ignition module, and the output end of the ignition angle adjustment module is connected to the ignition module via a bus; the ignition module is also connected to the engine; The ignition angle adjustment module is further configured to determine an ignition deceleration instruction of the ignition module based on the knock level of the knock factor and the load state after receiving a second trigger signal, so as to adjust the deceleration amplitude of the engine.

6. The engine control device according to claim 5, characterized in that: The weighted fusion module is further configured to determine whether the composite knock factor exceeds a second safety threshold and is less than the first safety threshold, and if so, send a third trigger signal to the ignition angle adjustment module; The ignition angle adjustment module is further configured to adjust the ignition angle of the engine to a preset angle after receiving the third trigger signal.

7. The engine control device according to claim 5, characterized in that: The ignition angle adjustment module is further configured to determine a knock frequency characteristic value based on the frequency band energy proportion, and adjust the ignition angle recovery speed of the engine according to the knock frequency characteristic value to avoid knock rebound during the ignition angle recovery process; The calculation formula of the ignition angle recovery speed is expressed as: ； Where, is the ignition angle recovery speed; is the ignition angular velocity at the current moment; Restore step length for ignition angle; is the knock frequency characteristic value.

8. The engine control device according to claim 3, characterized in that: The cylinder pressure adjustment module is configured to update the pressure fluctuation coefficient based on the frequency band energy ratio and the engine operating parameters using a least squares method, so that the cylinder pressure fluctuation range is lower than a preset standard deviation; wherein the forgetting factor of the least squares method is 0.98; The knock factor analysis module is further configured to receive and adjust the upper limit of the first counting unit according to the updated pressure fluctuation coefficient to update the basic knock factor; The cylinder pressure adjustment module is also used to detect the intake air temperature of the cylinder in the current engine in real time; The cylinder pressure adjustment module is further used to adjust the fuel enrichment concentration based on the intake temperature, the knock level of the knock factor and the real-time operating conditions of the engine to improve the air-fuel ratio of the mixture inside the cylinder; wherein the intake temperature is associated with the ignition angle of the engine.

9. The engine control device according to claim 8, characterized in that: The real-time operating conditions of the engine include at least speed, throttle opening, and turbocharger pressure; The cylinder pressure adjustment module is further configured to determine a basic enrichment amount by looking up a table based on the intake air temperature, the speed, the throttle opening, and the turbocharger pressure; The cylinder pressure adjustment module is further configured to adjust the enrichment amplitude according to the knock level of the knock factor, and obtain a final fuel enrichment concentration based on the basic enrichment amount and the enrichment amplitude.

10. An engine system, characterized in that: The engine system includes an engine and the engine control device according to any one of claims 1 to 9, wherein the engine control device is connected to the engine and is used to improve the knock effect of the engine.

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