Automobile fuel rail injection direction control method and system

Abstract

The present invention relates to the field of combustion optimization technology, and specifically to a method and system for controlling the injection direction of an automobile fuel rail, the method comprising: obtaining the injection velocity and pressure data of the injector at each acquisition moment in each compression stroke; obtaining the real velocity data in the compression stroke for each compression stroke; calculating the real injection amount and the original injection amount in the compression stroke; constructing a velocity cavitation evaluation coefficient for the compression stroke; constructing a pressure trend variation turbulence coefficient for each pressure sensor in the compression stroke; constructing a pressure synchronization deviation coefficient for each pressure sensor in the compression stroke; constructing a full range of pressure synchronization variation deviation coefficients for the compression stroke; constructing an engine injection abnormality index in the compression stroke; and adjusting the injection direction of the automobile fuel rail according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of the pressure sensor. The present invention can regulate the injection direction of the injector in the automobile fuel rail.

Description

Technical Field

[0001] The invention relates to the technical field of combustion optimization, and in particular to a method and system for controlling the injection direction of an automobile fuel rail. Background Art

[0002] The automobile fuel rail is an important part of the modern automobile fuel injection system. The function of the fuel rail is usually to store a certain amount of fuel. During the operation of the engine, the high-pressure fuel is distributed to each injector. The electronic control unit (ECU) further injects the fuel in the injector into the combustion chamber according to the engine implementation requirements to achieve efficient combustion and improve engine performance. The fuel injection direction is crucial to the fuel mixing and combustion process. It determines the fuel-air mixing ratio, which in turn affects the combustion efficiency and engine performance. Therefore, it is necessary to control the injection direction of the automobile fuel rail in combination with the engine operating conditions and driving needs.

[0003] Nowadays, automobiles usually use advanced fuel injection technology, such as high-pressure direct injection, etc. The injection direction and injection mode of the injector are precisely controlled by the ECU according to the engine load and speed. However, when the fuel passes through the nozzle under high pressure, the local pressure drops below the saturated vapor pressure of the fuel, which will cause the liquid to be partially or completely converted into gas, thereby producing cavitation. Since the cavitation flow of the fuel is unstable, if the cavitation is not properly controlled, it may cause incomplete combustion and cause fluctuations in engine performance. In response to the above problems, the present invention proposes a method and system for controlling the injection direction of an injector in a fuel rail of an automobile, which aims to adjust the injection direction of the injector in the fuel rail of an automobile according to changes in the combustion chamber pressure, optimize the combustion of the automobile engine, and improve the fuel conversion efficiency. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a method and system for controlling the injection direction of an automobile fuel rail. The technical solutions adopted are as follows:

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling the injection direction of a fuel rail of an automobile, the method comprising the following steps:

[0006] The injector injection flow rate and pressure data at each sampling time in each compression stroke are obtained through the flow rate sensor and each pressure sensor;

[0007] For each compression stroke, the real flow rate data in the compression stroke is obtained according to the injector injection flow rate at all sampling moments in the compression stroke; the real injection amount and the original injection amount in the compression stroke are calculated according to all the real flow rate data in the compression stroke, the injector injection flow rate at all sampling moments and the cross-sectional area of ​​the injector nozzle; the flow rate cavitation evaluation coefficient of the compression stroke is constructed according to the real injection amount and the original injection amount in the compression stroke; the pressure trend of each pressure sensor in the compression stroke is constructed according to the pressure data of each pressure sensor in the compression stroke at all sampling moments and the flow rate cavitation evaluation coefficient of the compression stroke. According to the pressure data of all pressure sensors in the compression stroke at all acquisition times, the pressure synchronization deviation coefficient of each pressure sensor in the compression stroke is constructed; according to the pressure data of all pressure sensors in the compression stroke at all acquisition times, the pressure synchronization deviation coefficient of the pressure sensor in the compression stroke and the pressure trend variation disorder coefficient, the full range of pressure synchronization variation deviation coefficient of the compression stroke is constructed; according to the full range of pressure synchronization variation deviation coefficient of the compression stroke and the difference between the actual injection amount of the adjacent previous compression stroke, the engine injection abnormality index in the compression stroke is constructed;

[0008] The injection direction of the automobile fuel rail is adjusted according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of the pressure sensor.

[0009] Furthermore, the step of obtaining the real flow rate data in the compression stroke according to the injector injection flow rate at all acquisition moments in the compression stroke includes:

[0010] The injector injection flow rates at all sampling moments in the compression stroke are combined into an original flow rate sequence in the order of the sampling moments. The anomaly detection algorithm is used to obtain the abnormal value of each injector injection flow rate in the original flow rate sequence. The threshold segmentation method is used to obtain the abnormal threshold of the abnormal value of all injector injection flow rates in the original flow rate sequence. The injector injection flow rate with an abnormal value less than the abnormal threshold is taken as the real flow rate data.

[0011] Further, the calculation of the actual fuel injection amount and the original fuel injection amount in the compression stroke includes:

[0012] All the real flow rate data in the compression stroke are combined into a real flow rate sequence according to the order of collection time, a curve fitting algorithm is used to obtain a fitting curve of all the real flow rate data in the real flow rate sequence, an integral result of the fitting curve in the interval between the start time and the end time of the fitting curve is obtained, and the product of the integral result and the cross-sectional area of ​​the injector nozzle is calculated as the real injection amount in the compression stroke;

[0013] For the original flow rate sequence, the calculation method of the real injection amount in the compression stroke is adopted to obtain the original injection amount in the compression stroke.

[0014] Furthermore, the flow velocity cavitation evaluation coefficient of the compression stroke is constructed according to the actual fuel injection amount and the original fuel injection amount in the compression stroke, including:

[0015] The absolute value of the difference between the actual fuel injection amount and the original fuel injection amount in the compression stroke is calculated, and the ratio of the absolute value of the difference to the actual fuel injection amount in the compression stroke is calculated. The ratio is used as the exponent of an exponential function with a natural constant as the base, and the calculation result of the exponential function is used as the flow velocity cavitation evaluation coefficient of the compression stroke.

[0016] Furthermore, the construction of the pressure trend variation turbulence coefficient of each pressure sensor in the compression stroke includes:

[0017] For each pressure sensor in the compression stroke, the pressure data of the pressure sensor at all acquisition moments in the compression stroke are combined into a pressure sequence in the order of acquisition moments, and the pressure sequence is used as the input of the curve fitting algorithm. The output is the pressure curve of the pressure sensor in the compression stroke, and the entropy eigenvalue calculation method is used to obtain the entropy eigenvalue of the pressure sequence;

[0018] Calculate the product of the entropy characteristic value and the flow velocity cavitation assessment coefficient of the compression stroke, recorded as the first product, calculate the ratio of the first product to the number of acquisition moments of the pressure sensor in the compression stroke, calculate the absolute value of the difference between the pressure data of the pressure sequence and the pressure curve at each acquisition moment, obtain the sum of the absolute values ​​of the difference of the pressure sequence at all acquisition moments, recorded as the first sum, and use the product of the first sum and the ratio as the pressure trend variation turbulence coefficient of the pressure sensor in the compression stroke.

[0019] Furthermore, the construction of the pressure synchronization deviation coefficient of each pressure sensor in the compression stroke includes:

[0020] For each pressure sensor in the compression stroke, calculate the absolute value of the difference in pressure data between the rth pressure sensor and the remaining pressure sensors at each sampling moment in the compression stroke, and calculate the average of the absolute values ​​of the difference between the rth pressure sensor and all the remaining pressure sensors at all sampling moments in the compression stroke as the pressure synchronization deviation coefficient of the rth pressure sensor in the compression stroke.

[0021] Furthermore, the construction of the omnidirectional pressure synchronous progressive deviation coefficient of the compression stroke includes:

[0022] Calculate the sum of the DTW distances between the rth pressure sensor and all other pressure sensors in the pressure sequence of the compression stroke, recorded as the second sum, calculate the product of the pressure synchronization deviation coefficient of the rth pressure sensor in the compression stroke and the pressure trend variation disorder coefficient, recorded as the second product, use the second product as the exponent of an exponential function with a natural constant as the base, calculate the product of the calculation result of the exponential function of the rth pressure sensor and the second sum, recorded as the third product, and use the sum of the third products of all pressure sensors in the compression stroke as the all-round pressure synchronization variation deviation coefficient of the compression stroke.

[0023] Further, the constructing of the engine injection abnormality index in the compression stroke includes:

[0024] Calculate the absolute value of the difference between the actual injection amount in the m-th compression stroke and the adjacent previous compression stroke, use the absolute value of the difference as the exponent of an exponential function with a natural constant as the base, calculate the product of the all-round pressure synchronous variation deviation coefficient of the m-th compression stroke and the calculation result of the exponential function, obtain the time interval between the m-th compression stroke and the adjacent previous compression stroke, use the sum of the time interval and 1 as the true number of a logarithmic function with 2 as the base, and use the ratio of the product to the calculation result of the logarithmic function as the engine injection abnormality index in the m-th compression stroke.

[0025] Further, the method of adjusting the injection direction of the automobile fuel rail according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of the pressure sensor includes:

[0026] When the engine injection abnormality index in the compression stroke is less than the preset injection abnormality threshold, the compression stroke is judged as a normal operation stroke, otherwise, the compression stroke is judged as a cavitation abnormality stroke, and the maximum value of the pressure trend variation turbulence coefficient of all pressure sensors in the cavitation abnormality stroke is counted to obtain the azimuth angle of the pressure sensor corresponding to the maximum value, and the oil replenishment operation is performed on the azimuth angle.

[0027] In a second aspect, an embodiment of the present invention further provides an automobile fuel rail injection direction control system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above methods when executing the computer program.

[0028] The present invention has at least the following beneficial effects:

[0029] The present invention detects the flow velocity of the injector inside the engine to obtain the original flow velocity sequence, performs abnormal detection on the original flow velocity sequence to obtain cavitation flow velocity data and real flow velocity data, and then calculates the original fuel injection amount and the real fuel injection amount in the compression stroke, and constructs the flow velocity cavitation evaluation coefficient of the compression stroke to measure the influence of cavitation on the fuel injection amount. The pressure sequence is obtained by using the pressure sensor arranged in the combustion chamber, and the pressure trend variation turbulence coefficient of the pressure sensor in the compression stroke is constructed according to the fluctuation of the data in the pressure sequence, which characterizes the possibility of cavitation occurring in the corresponding position of a single pressure sensor; the pressure sequence obtained by all pressure sensors in the combustion chamber is comprehensively considered, and the omnidirectional pressure synchronous variation deviation coefficient of the compression stroke is constructed according to the synchronous variation of the pressure sequence of all pressure sensors, which improves the accuracy of the analysis of cavitation occurring in the compression stroke; the engine injection abnormality index is further obtained in combination with the time interval of the engine performing the Otto cycle, and the relationship between the engine working condition and the cavitation phenomenon is analyzed; the position where the cavitation phenomenon occurs in the combustion chamber is obtained according to the engine injection abnormality index and the pressure trend variation turbulence coefficient, and the oil replenishment operation is performed on the position. The present invention solves the problem that the conventional control method cannot timely regulate the randomly occurring cavitation phenomenon, and can timely adjust the injection amount and injection direction, improve the fuel-air mixing ratio, and enhance the combustion efficiency of the fuel inside the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A flowchart of a method for controlling the injection direction of an automobile fuel rail provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of a single combustion chamber of the engine;

[0033] Figure 3 It is a schematic diagram of the arrangement of pressure sensors;

[0034] Figure 4 The figure is a flow chart of obtaining the engine injection abnormality index. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the specific implementation, structure, features and effects of a method and system for controlling the injection direction of an automobile fuel rail proposed by the present invention in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0037] The specific scheme of a method and system for controlling the injection direction of an automobile fuel rail provided by the present invention is described in detail below with reference to the accompanying drawings.

[0038] See also Figure 1 , which shows a flowchart of a method for controlling the injection direction of an automobile fuel rail provided by an embodiment of the present invention, the method comprising the following steps:

[0039] Step S001, obtaining the injector injection flow rate and pressure data of the flow rate sensor and the pressure sensor in each compression stroke at each acquisition moment.

[0040] Schematic diagram of a single combustion chamber of an engine Figure 2 As shown in the figure, the piston moves linearly between the top dead center and the bottom dead center of the combustion chamber, and the linear rotation is converted into rotational motion through the connecting rod and the crankshaft. During the intake stroke, the piston moves downward, and the intake port opens, allowing air to enter the combustion chamber. During the compression stroke, the piston moves upward, and the injector sprays fuel. The power stroke is when the piston moves to the top dead center, triggering the spark plug to ignite, and the compressed mixed gas quickly burns to push the piston downward. After the power stroke, the piston moves upward to discharge the burned exhaust gas, which is called the exhaust stroke.

[0041] The injection direction of the automobile fuel rail refers to the injection direction of the combustion chamber injector. In order to obtain the injection situation of the fuel in the combustion chamber, this embodiment only collects data during the compression stroke, and collects data at equal intervals through a flow rate sensor placed at the injection port of the injector. m (k) represents the injector injection velocity at the kth sampling time in the mth compression stroke during the engine operation. When the piston moves to the top dead center, the remaining cylinders in the combustion chamber are evenly arranged horizontally in the vertical direction. r There are N pressure sensors. r =8, implementers can adjust according to actual needs. The schematic diagram of pressure sensor layout is as follows Figure 3 As shown in Figure 2. Similarly, pressure data is collected only during the compression stroke. Indicates the pressure data of the rth pressure sensor at the kth acquisition time in the mth compression stroke. In order to obtain sensor data more accurately, this embodiment sets the acquisition frequency of the sensor to 100kHz, and the implementer of the sensor acquisition frequency can also set it by himself. During the acquisition process, data may be missing. In order to avoid affecting subsequent analysis, this embodiment uses regression filling method to fill the missing values. Among them, the regression filling method is a well-known technology and will not be repeated in this embodiment.

[0042] Step S002, perform abnormal detection on the original flow velocity sequence in the compression stroke to obtain the real flow velocity data, combine the original flow velocity sequence to obtain the flow velocity cavitation evaluation coefficient, combine the pressure sequence and pressure curve of a single pressure sensor to obtain the pressure trend variation turbulence coefficient, in order to measure the impact of cavitation, combine the pressure data of multi-directional pressure sensors to obtain the all-round pressure synchronous variation deviation coefficient, and finally calculate the engine injection abnormality index in the compression stroke.

[0043] Cavitation is a fluid dynamics phenomenon that usually occurs during high-pressure fuel injection. When the fuel flows in the high-pressure area inside the injector, the pressure drops below the saturated vapor pressure of the fuel, and the fuel is partially or completely converted into the gas phase, forming cavitation bubbles. Cavitation may lead to insufficient fuel injection or uneven fuel injection, resulting in incomplete combustion of the fuel inside the combustion chamber, forming carbon deposits and affecting the service life of the engine. However, due to the instability and randomness of cavitation, current technology cannot accurately grasp the timing and accuracy of cavitation. Therefore, it is necessary to combine the pressure data of the combustion chamber inside the engine and the flow rate data of the injector to evaluate the cavitation phenomenon and optimize the injection direction of the injector to improve the combustion efficiency of the fuel.

[0044] Theoretically, the flow rate of the injector is stable during the compression stroke. However, if cavitation occurs in the nozzle, the flow rate corresponding to the cavitation is larger, while the flow rate corresponding to the real fuel is smaller. Cavitation may occur intermittently during the entire compression stroke, and no fuel is injected into the combustion chamber in the cavitation. Therefore, it is necessary to calculate the real injection amount. The injector injection flow rates at all sampling moments in the mth compression stroke are combined into the original flow rate sequence v according to the sampling time sequence. m , and the original flow velocity sequence v mAs the input of the Local Outlier Factor (LOF) algorithm, the hyperparameter K is set to the mean of all the injector jet velocities in the original velocity sequence within the compression stroke, rounded down, and the output of the LOF algorithm is the LOF value of each injector jet velocity in the original velocity sequence. Among them, the implementer can also set the value of the hyperparameter K by himself. And the LOF value of all the injector jet velocities in the original velocity sequence is used as the input of the Otsu threshold method, and the output is the abnormal threshold value of the LOF value of all the injector jet velocities in the original velocity sequence. The injector jet velocity with a LOF value greater than or equal to the abnormal threshold is used as the cavitation velocity data, and the injector jet velocity with a LOF value less than the abnormal threshold is used as the real velocity data. Among them, the LOF algorithm and the Otsu threshold method are well-known technologies, and this embodiment will not be repeated.

[0045] Arrange the real flow rate data in the order of collection time to form a real flow rate sequence In order to evaluate the effect of cavitation on the injection amount of the injector, the original flow velocity sequence v m and the real flow rate series As the input of the least squares method, the algorithm outputs the fitting curves of the two sequences respectively. and The least square method is a well-known technique and will not be described in detail in this embodiment. The velocity cavitation evaluation coefficient is obtained as follows:

[0046]

[0047]

[0048]

[0049] In the formula, α m represents the velocity cavitation evaluation coefficient of the mth compression stroke, exp() represents an exponential function with a natural constant as the base, and b m and c m They represent the original injection amount and the actual injection amount in the mth compression stroke, and They represent the fitting curves of the original flow velocity sequence in the mth compression stroke. The start and end time of and They represent the fitting curves of the real flow rate sequence in the mth compression stroke. The start and end time of the injection nozzle, A represents the cross-sectional area of ​​the injector nozzle, and They represent the fitting curves of the original flow velocity sequence and the real flow velocity sequence in the mth compression stroke, t represents the time axis, d tIndicates the integration of time. The cross-sectional area of ​​the injector nozzle is determined by the engine model and is obtained by querying the relevant parameters of the engine.

[0050] The time and frequency of cavitation are random. When cavitation occurs more frequently in the compression stroke, the abnormal velocity value corresponding to the cavitation will be detected and eliminated, and the final value of the actual injection amount is smaller. The absolute value of the difference between the actual injection amount and the original injection amount is larger, and the final calculated velocity cavitation evaluation coefficient α m On the contrary, if cavitation does not occur or occurs less in the compression stroke, the absolute value of the difference between the actual injection amount and the original injection amount is smaller, which ultimately makes α m The value of is smaller.

[0051] Since the timing and degree of cavitation are random, the flow rate sensor can only determine the larger degree of cavitation, and may not be able to eliminate the smaller degree of cavitation. Therefore, it is necessary to further analyze the phenomenon and degree of cavitation in combination with the pressure sensor data.

[0052] In the compression stroke, as the piston moves from the bottom dead center to the top dead center, the air entering in the intake stroke and the atomized fuel sprayed by the injector will be compressed, so the pressure data will show a gradual upward trend. If cavitation occurs, the bubbles formed by cavitation will quickly collapse in the high-pressure area of ​​the nozzle, and the pressure in the combustion chamber will fluctuate, so the pressure data can be analyzed.

[0053] The pressure data collected by the rth pressure sensor in the mth compression stroke is combined into a pressure sequence according to the order of collection time. It is used as the input of the least squares method, and the output is the pressure curve of the rth pressure sensor at the mth compression stroke. In order to measure the randomness of cavitation occurrence, the pressure series As the input of the Approximate Entropy (ApEn) algorithm, the value of the parameter m in the algorithm is one tenth of the length of the pressure sequence. The value of the parameter m can also be set by the implementer. The algorithm output is the approximate entropy value of the pressure sequence. ApEn algorithm is a well-known technology and will not be described in detail in this embodiment. Combining the pressure sequence and the pressure curve, the pressure trend variation disorder coefficient of a single pressure sensor can be obtained:

[0054]

[0055] In the formula, It represents the pressure trend variation turbulence coefficient of the rth pressure sensor in the mth compression stroke, Represents the pressure sequence of the rth pressure sensor in the mth compression stroke The approximate entropy value of m represents the velocity cavitation evaluation coefficient of the mth compression stroke, N m represents the number of acquisition moments of the pressure sensor in the mth compression stroke, and They respectively represent the pressure sequence of the rth pressure sensor in the mth compression stroke and the pressure curve at the kth acquisition time.

[0056] If the pressure data at the position corresponding to the rth sensor fluctuates violently, it indicates that the cavitation of the injector is more serious in the compression stroke where the rth sensor is located. At this time, due to the large fluctuations and strong randomness of the data in the pressure sequence, the approximate entropy is obtained by the ApEn algorithm. In addition, due to the large fluctuation of data in the sequence, the difference between the fitting curve and the pressure trend is large, which eventually makes the pressure trend change disorder coefficient On the contrary, if the cavitation reaction in the current compression stroke is weak, the data in the pressure series basically presents a steady upward trend without large fluctuations. The value is smaller.

[0057] Theoretically, the pressure data fluctuations detected by each pressure sensor during the compression stroke are consistent. However, when cavitation occurs at the injection port of the injector, the direction of the collapse of the cavitation bubbles formed by the cavitation phenomenon is uncertain due to the pressure reduction at the injection port, resulting in inconsistent pressure data fluctuations detected by the pressure sensors in various positions of the combustion chamber. Therefore, it is necessary to more accurately evaluate the timing and extent of cavitation based on the changes in the data from the omnidirectional pressure sensors.

[0058] Combining N r The change of pressure data detected by the azimuth pressure sensor is used to obtain the deviation coefficient of the synchronous variation of the omnidirectional pressure in the compression stroke:

[0059]

[0060]

[0061]

[0062] In the formula, ξ m Indicates the full range of pressure synchronous variation deviation coefficient of the mth compression stroke, N r Indicates the number of pressure sensors. In this embodiment, N r =8, represents the deviation distance weight of the rth pressure sensor in the mth compression stroke, exp() represents an exponential function with a natural constant as the base, represents the pressure synchronization deviation coefficient of the rth pressure sensor in the mth compression stroke, It represents the pressure trend variation turbulence coefficient of the rth pressure sensor in the mth compression stroke, N m represents the number of acquisition moments of the pressure sensor in the mth compression stroke, and Respectively represent the pressure data of the rth and jth pressure sensors at the kth acquisition time of the pressure sequence of the mth compression stroke, and They respectively represent the pressure sequences of the rth and jth pressure sensors in the mth compression stroke, DTW() represents a dynamic time warping (DTW) distance operation, and the calculation of the DTW distance is a well-known technology and will not be repeated in this embodiment.

[0063] If the cavitation phenomenon in the current compression stroke is more serious, that is, the collapse directions of the bubbles caused by cavitation are different, it will cause the pressure data detected by the pressure sensors in each direction to fluctuate greatly, resulting in deviation distance weight. Synchronous deviation coefficient of pressure The value of is large, which eventually makes the omnidirectional pressure synchronous variation deviation coefficient ξ m On the contrary, if the cavitation phenomenon is relatively light in the current compression stroke, the pressure data in each direction will increase synchronously with the piston compression, and finally obtain ξ m The value of is smaller.

[0064] The cavitation phenomenon of the combustion chamber injector is closely related to the working condition of the engine. When the engine speed is faster, the Otto cycle inside the engine is faster, so the pressure of the injector is greater, and the cavitation phenomenon is more likely to occur. Therefore, the cavitation phenomenon of the compression stroke in the current Otto cycle is judged by combining the differences between the combustion chambers of adjacent Otto cycle engines, and finally the engine injection abnormality index is obtained:

[0065]

[0066] In the formula, represents the engine injection abnormality index in the mth compression stroke, ξ m represents the deviation coefficient of the synchronous variation of the full range of pressure in the mth compression stroke, exp() represents the exponential function with the natural constant as the base, c m and c m-1 They represent the actual fuel injection amount obtained in the mth and m-1th compression strokes inside the engine respectively, log2() represents the logarithmic function with base 2, It represents the time interval between the mth and m-1th compression strokes, specifically, the time interval between the start times of the compression strokes in two adjacent Otto cycles of the engine.

[0067] If the time interval between two adjacent Otto cycles of the engine is small when the engine speed increases during acceleration, that is, The smaller the value, and the greater the difference in the actual injection amount between two adjacent compression strokes, if the cavitation in the current compression stroke is more serious, the full-range pressure synchronous variation deviation coefficient ξ is obtained. m The value of is large, and finally the engine injection abnormality index is obtained On the contrary, if the engine has been running smoothly and the ξ obtained in the current compression stroke is m The value of is small, and finally the engine injection abnormality index is obtained The value is small. The flow chart of obtaining the engine injection abnormality index is as follows: Figure 4 shown.

[0068] Step S003, adjusting the injection direction of the automobile fuel rail according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of each pressure sensor.

[0069] When the engine injection abnormality index in the mth compression stroke The larger the value, the more serious the abnormality of fuel injection in the engine combustion chamber during the compression stroke. Furthermore, an injection abnormality threshold W is set, and the compression stroke with an engine injection abnormality index greater than or equal to W is determined as a cavitation abnormality stroke, and the compression stroke with an engine injection abnormality index less than W is determined as a normal operation stroke. Among them, the value of the injection abnormality threshold W can be set by the implementer. In this embodiment, W is 5. In the cavitation abnormality stroke, assuming that the m-th compression stroke is a cavitation abnormality stroke, obtain the maximum value of the pressure trend variation turbulence coefficient of all pressure sensors in the m-th compression stroke, and record the azimuth angle of the pressure sensor corresponding to the maximum value as O. m .O m It means that the actual fuel injection amount is small due to the influence of cavitation bubble collapse, which makes the fuel-air mixture ratio in this area of ​​the combustion chamber small. m The information is transmitted to the vehicle's ECU, which performs fuel replenishment operations at that azimuth before the spark plug ignites, optimizes the fuel-air ratio in the combustion chamber, reduces the impact of cavitation on incomplete fuel combustion, and improves fuel utilization.

[0070] Based on the same inventive concept as the above method, an embodiment of the present invention further provides an automobile fuel rail injection direction control system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above automobile fuel rail injection direction control methods when executing the computer program.

[0071] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0072] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the injection direction of an automobile fuel rail, characterized in that: The method comprises the following steps: The injector injection flow rate and pressure data at each sampling time in each compression stroke are obtained through the flow rate sensor and each pressure sensor; For each compression stroke, the real flow rate data in the compression stroke is obtained according to the injector injection flow rate at all sampling moments in the compression stroke; the real injection amount and the original injection amount in the compression stroke are calculated according to all the real flow rate data in the compression stroke, the injector injection flow rate at all sampling moments and the cross-sectional area of ​​the injector nozzle; the flow rate cavitation evaluation coefficient of the compression stroke is constructed according to the real injection amount and the original injection amount in the compression stroke; the pressure trend of each pressure sensor in the compression stroke is constructed according to the pressure data of each pressure sensor in the compression stroke at all sampling moments and the flow rate cavitation evaluation coefficient of the compression stroke. According to the pressure data of all pressure sensors in the compression stroke at all acquisition times, the pressure synchronization deviation coefficient of each pressure sensor in the compression stroke is constructed; according to the pressure data of all pressure sensors in the compression stroke at all acquisition times, the pressure synchronization deviation coefficient of the pressure sensor in the compression stroke and the pressure trend variation disorder coefficient, the full range of pressure synchronization variation deviation coefficient of the compression stroke is constructed; according to the full range of pressure synchronization variation deviation coefficient of the compression stroke and the difference between the actual injection amount of the adjacent previous compression stroke, the engine injection abnormality index in the compression stroke is constructed; The injection direction of the automobile fuel rail is adjusted according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of the pressure sensor.

2. A method for controlling the injection direction of an automobile fuel rail as claimed in claim 1, characterized in that: The method of obtaining the real flow rate data in the compression stroke according to the injector injection flow rate at all acquisition moments in the compression stroke includes: The injector injection flow rates at all sampling moments in the compression stroke are combined into an original flow rate sequence in the order of the sampling moments. The anomaly detection algorithm is used to obtain the abnormal value of each injector injection flow rate in the original flow rate sequence. The threshold segmentation method is used to obtain the abnormal threshold of the abnormal value of all injector injection flow rates in the original flow rate sequence. The injector injection flow rate with an abnormal value less than the abnormal threshold is taken as the real flow rate data.

3. A method for controlling the injection direction of an automobile fuel rail as claimed in claim 2, characterized in that: The calculation of the actual fuel injection amount and the original fuel injection amount in the compression stroke includes: All the real flow rate data in the compression stroke are combined into a real flow rate sequence according to the order of collection time, a curve fitting algorithm is used to obtain a fitting curve of all the real flow rate data in the real flow rate sequence, an integral result of the fitting curve in the interval between the start time and the end time of the fitting curve is obtained, and the product of the integral result and the cross-sectional area of ​​the injector nozzle is calculated as the real injection amount in the compression stroke; For the original flow rate sequence, the calculation method of the real injection amount in the compression stroke is adopted to obtain the original injection amount in the compression stroke.

4. The method for controlling the injection direction of an automobile fuel rail according to claim 1, characterized in that: The method of constructing a flow velocity cavitation evaluation coefficient of the compression stroke according to the actual fuel injection amount and the original fuel injection amount in the compression stroke includes: The absolute value of the difference between the actual fuel injection amount and the original fuel injection amount in the compression stroke is calculated, and the ratio of the absolute value of the difference to the actual fuel injection amount in the compression stroke is calculated. The ratio is used as the exponent of an exponential function with a natural constant as the base, and the calculation result of the exponential function is used as the flow velocity cavitation evaluation coefficient of the compression stroke.

5. The method for controlling the injection direction of an automobile fuel rail according to claim 1, characterized in that: The step of constructing the pressure trend variation turbulence coefficient of each pressure sensor in the compression stroke includes: For each pressure sensor in the compression stroke, the pressure data of the pressure sensor at all acquisition moments in the compression stroke are combined into a pressure sequence in the order of acquisition moments, and the pressure sequence is used as the input of the curve fitting algorithm. The output is the pressure curve of the pressure sensor in the compression stroke, and the entropy eigenvalue calculation method is used to obtain the entropy eigenvalue of the pressure sequence; Calculate the product of the entropy characteristic value and the flow velocity cavitation assessment coefficient of the compression stroke, recorded as the first product, calculate the ratio of the first product to the number of acquisition moments of the pressure sensor in the compression stroke, calculate the absolute value of the difference between the pressure data of the pressure sequence and the pressure curve at each acquisition moment, obtain the sum of the absolute values ​​of the difference of the pressure sequence at all acquisition moments, recorded as the first sum, and use the product of the first sum and the ratio as the pressure trend variation turbulence coefficient of the pressure sensor in the compression stroke.

6. The method for controlling the injection direction of an automobile fuel rail according to claim 1, characterized in that: The step of constructing the pressure synchronization deviation coefficient of each pressure sensor in the compression stroke includes: For each pressure sensor in the compression stroke, calculate the absolute value of the difference in pressure data between the rth pressure sensor and the remaining pressure sensors at each sampling moment in the compression stroke, and calculate the average of the absolute values ​​of the difference between the rth pressure sensor and all the remaining pressure sensors at all sampling moments in the compression stroke as the pressure synchronization deviation coefficient of the rth pressure sensor in the compression stroke.

7. The method for controlling the injection direction of an automobile fuel rail as claimed in claim 5, characterized in that: The all-round pressure synchronous variation deviation coefficient for constructing the compression stroke includes: Calculate the sum of the DTW distances between the rth pressure sensor and all other pressure sensors in the pressure sequence of the compression stroke, recorded as the second sum, calculate the product of the pressure synchronization deviation coefficient of the rth pressure sensor in the compression stroke and the pressure trend variation disorder coefficient, recorded as the second product, use the second product as the exponent of an exponential function with a natural constant as the base, calculate the product of the calculation result of the exponential function of the rth pressure sensor and the second sum, recorded as the third product, and use the sum of the third products of all pressure sensors in the compression stroke as the all-round pressure synchronization variation deviation coefficient of the compression stroke.

8. The method for controlling the injection direction of an automobile fuel rail as claimed in claim 1, characterized in that: The constructing of the engine injection abnormality index in the compression stroke comprises: Calculate the absolute value of the difference between the actual injection amount in the m-th compression stroke and the adjacent previous compression stroke, use the absolute value of the difference as the exponent of an exponential function with a natural constant as the base, calculate the product of the all-round pressure synchronous variation deviation coefficient of the m-th compression stroke and the calculation result of the exponential function, obtain the time interval between the m-th compression stroke and the adjacent previous compression stroke, use the sum of the time interval and 1 as the true number of a logarithmic function with 2 as the base, and use the ratio of the product to the calculation result of the logarithmic function as the engine injection abnormality index in the m-th compression stroke.

9. The method for controlling the injection direction of an automobile fuel rail according to claim 1, characterized in that: The method of adjusting the injection direction of the automobile fuel rail according to the engine injection abnormality index in the compression stroke and the pressure trend variation turbulence coefficient of the pressure sensor includes: When the engine injection abnormality index in the compression stroke is less than the preset injection abnormality threshold, the compression stroke is judged as a normal operation stroke, otherwise, the compression stroke is judged as a cavitation abnormality stroke, and the maximum value of the pressure trend variation turbulence coefficient of all pressure sensors in the cavitation abnormality stroke is counted to obtain the azimuth angle of the pressure sensor corresponding to the maximum value, and the oil replenishment operation is performed on the azimuth angle.

10. An automobile fuel rail injection direction control system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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