Differential pressure pipeline icing identification method and device, medium and vehicle control unit

Abstract

The invention relates to the technical field of intelligent automobiles, in particular to a differential pressure pipeline icing identification method and device, a medium and a vehicle control unit. The icing identification method comprises the following steps: acquiring original information when the differential pressure pipeline is iced and not iced; normalizing distribution processing is carried out on the original information, and upstream pressure difference pipeline input data and downstream pressure difference pipeline input data are calculated; the upstream pressure difference pipeline input data and the downstream pressure difference pipeline input data are compared with an upstream ice melting and freezing judgment threshold value and a downstream ice melting and freezing judgment threshold value respectively; and judging whether the differential pressure pipeline is frozen or not according to a comparison result. The icing identification method does not require dynamic operation of the engine. That is, icing identification can be carried out under both dynamic and steady working conditions. The method is not only suitable for icing identification of a traditional fuel vehicle, but also suitable for icing identification of a hybrid vehicle.

Description

Technical Field

[0001] The present invention relates to the field of intelligent automobile technology, and in particular to a method, device, medium and vehicle controller for identifying icing in a pressure differential pipeline. Background Art

[0002] With the tightening of emission regulations, the use of GPF particulate filters is becoming more and more popular. Therefore, it is particularly important to diagnose GPF-related faults in a timely and accurate manner. The differential pressure sensor is one of the components for diagnosing GPF-related faults. However, when any of the upstream and downstream pressure-taking pipelines of the differential pressure sensor is blocked by ice, the control system will falsely report a fault. Therefore, accurately identifying ice formation and suppressing fault diagnosis and accurately identifying ice melting and releasing fault diagnosis are the prerequisites for avoiding false faults.

[0003] In traditional fuel vehicles, the engine operates under many dynamic conditions. Under normal circumstances, the upstream and downstream pressure values ​​measured by the differential pressure sensor will change with the change of exhaust flow, such as Figure 1 However, when the pipe of the differential pressure sensor is frozen, the measured pressure signal will remain fixed and will not change with the change of exhaust flow rate, such as Figure 2 The traditional icing identification scheme is to calculate the degree to which the pressure signal follows the exhaust flow to determine whether it is icing or melting. That is, when the exhaust flow changes, if the pressure signal does not change in the same direction as the exhaust flow, it can be determined as icing.

[0004] However, with the application of various hybrid topology types, the diversity of the engine's role in the vehicle power system has brought challenges to the determination of pipeline icing. Unlike traditional fuel vehicles, when the engine is used in series or as a range extender, the dynamic working conditions of the engine are reduced. Especially when the engine is used as a range extender, most of the time, the engine is running in a steady state, and the exhaust flow is stable, so the upstream and downstream pressures measured by the pressure differential sensor are also stable. Due to the lack of exhaust flow changes, traditional ice identification methods are no longer applicable, such as Figure 3 . Summary of the invention

[0005] The invention discloses a method, a device, a medium and a vehicle controller for identifying icing of a pressure differential pipeline, which can accurately identify the icing problem of the pressure differential pipeline of a fuel vehicle and a hybrid vehicle.

[0006] In order to achieve the above-mentioned purpose, on the one hand, a method for identifying ice formation in a pressure differential pipeline is provided, and the specific method is as follows:

[0007] Get the original information when the pressure differential pipeline is frozen and not frozen;

[0008] Perform normal distribution processing on the original information, and calculate the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data;

[0009] The upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data are compared with the upstream ice melting judgment threshold and the downstream ice melting judgment threshold respectively;

[0010] Based on the comparison results, determine whether the pressure difference pipeline is frozen.

[0011] Furthermore, the original information includes:

[0012] Upstream pressure signal and downstream pressure signal.

[0013] Furthermore, the original information is processed for normal distribution, and the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data are calculated. The specific method is as follows:

[0014] Acquire a first preset number of upstream and downstream pressure signals, and calculate the standard deviations of the upstream and downstream pressure signals respectively as first data;

[0015] Obtain a second preset number of first data as above, and calculate the average of the first data as the second data;

[0016] The third preset number of second data is obtained in the same manner as above, and the average of the second data is calculated as the upstream pressure difference pipeline input data and the downstream pressure difference pipeline input data.

[0017] Furthermore, the upstream ice melting judgment threshold and the downstream ice melting judgment threshold are specifically calculated as follows:

[0018] Get historical information on when the pressure differential pipeline is frozen and not frozen;

[0019] Normalize the distribution of historical information;

[0020] A two-dimensional data coordinate system is constructed according to the third data obtained by normalized distribution processing, wherein the abscissa of the two-dimensional data coordinate system is the pressure difference vibration amplitude information, and the two ordinates are respectively the sample distribution quantity information and the probability density information;

[0021] The upstream ice-melting judgment threshold and the downstream ice-melting judgment threshold are calculated according to the two-dimensional data coordinate system.

[0022] Furthermore, the specific method for determining whether the pressure difference pipeline is frozen is as follows:

[0023] When the input data of the upstream differential pressure pipeline is less than the upstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the first freezing target number, it is judged that the upstream differential pressure pipeline is frozen;

[0024] When the input data of the upstream pressure difference pipeline is greater than the upstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the first ice melting target number, it is determined that the upstream pressure difference pipeline is ice melting.

[0025] Furthermore, the specific method for determining whether the pressure difference pipeline is frozen is as follows:

[0026] When the input data of the downstream differential pressure pipeline is less than the downstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the second freezing target number, it is judged that the downstream differential pressure pipeline is frozen;

[0027] When the downstream differential pressure pipeline input data is greater than the downstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the second ice melting target number, it is determined that the downstream differential pressure pipeline is ice melting.

[0028] Further, when the upstream pressure difference pipeline or the downstream pressure difference pipeline is judged to be frozen, it is finally judged that the pipeline is frozen;

[0029] When the upstream pressure difference pipeline and the downstream pressure difference pipeline are judged to be free of ice, it is finally judged that the pipeline is free of ice.

[0030] In order to achieve the above object, on the other hand, a pressure differential pipeline icing identification device is provided, comprising:

[0031] An information acquisition module is used to obtain the original information when the pressure difference pipeline is frozen or not frozen;

[0032] The input calculation module performs normal distribution processing on the original information and calculates the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data;

[0033] The judgment module compares the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data with the upstream thawing judgment threshold and the downstream thawing judgment threshold respectively; and judges whether the differential pressure pipeline is frozen according to the comparison result.

[0034] To achieve the above-mentioned purpose, on the other hand, a storage medium is provided, which stores a plurality of instructions, and a processor loads the instructions to execute the above-mentioned pressure difference pipeline icing identification method.

[0035] In order to achieve the above-mentioned purpose, on the other hand, a vehicle controller is provided, which is installed in a fuel vehicle or a hybrid vehicle, and includes the above-mentioned pressure difference pipeline icing identification device and the above-mentioned storage medium.

[0036] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0037] 1. The ice recognition method of the present invention does not require the engine to be running dynamically. That is, ice recognition can be performed in both dynamic and steady-state conditions; it is not only applicable to ice recognition of traditional fuel vehicles, but also to ice recognition of hybrid vehicles.

[0038] 2. The ice recognition of the present invention takes a short time. When the engine is running, it takes 81 seconds to complete the judgment. The traditional recognition method requires an average cumulative time of about 300 seconds for the engine to dynamically run under variable working conditions. The new method shortens the time required by the traditional method by 73%. The shortened ice judgment time can release subsequent GPF-related fault diagnosis as early as possible, thereby improving the fault diagnosis rate IUPRM.

[0039] It should be noted that the terms "first", "second" and similar terms used in this article are only for describing the various components in the technical solution, and do not constitute a limitation of the technical solution, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; elements with "first", "second" and similar terms indicate that the corresponding technical solution contains at least one of the element. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention and facilitate further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.

[0041] The same reference numerals in the accompanying drawings represent the same components, specifically:

[0042] Figure 1 This is a graph showing the changes in upstream and downstream pressures following exhaust flow when a traditional fuel vehicle is not frozen.

[0043] Figure 2 This is a diagram showing that the upstream and downstream pressures of a traditional fuel vehicle do not change with the exhaust flow rate when ice forms.

[0044] Figure 3 This is a diagram of the exhaust flow and upstream and downstream pressure changes of the extended-range engine.

[0045] Figure 4 Schematic diagram of sample mean distribution during freezing.

[0046] Figure 5 Schematic diagram of sample mean distribution when there is no ice.

[0047] Figure 6 This is a schematic diagram of the overall process of Example 1.

[0048] Figure 7 Schematic diagram of the data flow for calculating the upstream and downstream pressure difference pipeline input. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described below are only for explaining the technical solutions of the present invention, rather than for limiting the present invention. In addition, the parts described in the embodiments or the accompanying drawings are only examples of the relevant parts of the present invention, rather than the whole of the present invention.

[0050] Under normal circumstances, one of the characteristics of the pressure signal is that when the exhaust flow rate is stable, the pressure value is not fixed, but vibrates around a central value with a significant amplitude. The pressure amplitude is different for different exhaust flow rates. In addition, the operating conditions of the engine are random when driving. Therefore, the value of the pressure signal amplitude is a random variable. In addition, when the pipeline is frozen, no matter how much the exhaust flow rate is, the pressure signal will not vibrate, or the amplitude is very small. Therefore, the distribution of this random variable has a clear distinction between the two conditions of ice and non-ice. It's just that the probability density function is unknown.

[0051] According to the central limit theorem, for a random variable, even if its probability density function is unknown, when the sample size is large enough, the distribution of the sample mean tends to be normally distributed. In practical applications, the sample size for calculating the sample mean is no less than 30. The standard deviation of the pressure relative to the central value is used to represent the amplitude, and the mean of multiple standard deviations is used as the sample. Then the distribution of the mean of no less than 30 samples should be close to the normal distribution. Taking the measured pressure of the upstream pipeline as an example, the mean distribution of the statistically obtained samples under non-icing and icing conditions is as follows: Figure 4 and Figure 5 shown.

[0052] Embodiment 1:

[0053] A method for identifying ice formation in a pressure differential pipeline, the overall process is as follows: Figure 6 As shown, the specific steps are as follows:

[0054] S1. Obtain the original information when the pressure difference pipeline is frozen and not frozen.

[0055] In step S1, the original information includes: an upstream pressure signal and a downstream pressure signal.

[0056] S2. Perform normal distribution processing on the original information, and calculate the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data.

[0057] In step S2, the original information is processed for normal distribution, and the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data are calculated. The specific process is as follows: Figure 7 As shown, the specific steps are as follows:

[0058] S21, obtaining a first preset number of upstream and downstream pressure signals, and calculating the standard deviations of the upstream and downstream pressure signals respectively as first data;

[0059] S23, obtaining a second preset number of first data as above, and calculating an average of the first data as the second data;

[0060] S24. Obtain a third preset number of second data as above, calculate the average of the second data, and use the average as the upstream pressure difference pipeline input data and the downstream pressure difference pipeline input data.

[0061] S3. Compare the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data with the upstream ice melting judgment threshold and the downstream ice melting judgment threshold, respectively.

[0062] In step S3, the upstream ice melting judgment threshold and the downstream ice melting judgment threshold are specifically calculated as follows:

[0063] S31, obtaining historical information of when the pressure differential pipeline is frozen and when it is not frozen;

[0064] S32, performing normal distribution processing on historical information;

[0065] S33, constructing a two-dimensional data coordinate system according to the third data obtained by normalized distribution processing, wherein the abscissa of the two-dimensional data coordinate system is the pressure difference vibration amplitude information, and the two ordinates are respectively the sample distribution quantity information and the probability density information;

[0066] S34, calculating the upstream ice melting judgment threshold and the downstream ice melting judgment threshold according to the two-dimensional data coordinate system, the specific formula is:

[0067] Upstream icing judgment threshold: μ frzUs +2σ frzUs

[0068] Upstream ice melting judgment threshold: μ meltUs -4σ meltUs

[0069] Downstream icing judgment threshold: μ frzDs +2σ frzDs

[0070] Downstream ice melting judgment threshold: μ meltDs -4σ meltDs

[0071] S4. Determine whether the pressure difference pipeline is frozen based on the comparison result.

[0072] When the input data of the upstream differential pressure pipeline is less than the upstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the first freezing target number, it is judged that the upstream differential pressure pipeline is frozen;

[0073] When the input data of the upstream differential pressure pipeline is greater than the upstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the first ice melting target number, it is judged that the upstream differential pressure pipeline is ice melting;

[0074] When the input data of the downstream differential pressure pipeline is less than the downstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the second freezing target number, it is judged that the downstream differential pressure pipeline is frozen;

[0075] When the downstream differential pressure pipeline input data is greater than the downstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the second ice melting target number, it is determined that the downstream differential pressure pipeline is ice melting.

[0076] When the upstream differential pressure pipeline or the downstream differential pressure pipeline is judged to be frozen, it is finally judged that the pipeline is frozen;

[0077] When the upstream pressure difference pipeline and the downstream pressure difference pipeline are judged to be free of ice, it is finally judged that the pipeline is free of ice.

[0078] Embodiment 2:

[0079] A pressure differential pipeline icing identification device, comprising:

[0080] An information acquisition module is used to obtain the original information when the pressure difference pipeline is frozen or not frozen;

[0081] The input calculation module performs normal distribution processing on the original information and calculates the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data;

[0082] The judgment module compares the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data with the upstream thawing judgment threshold and the downstream thawing judgment threshold respectively; and judges whether the differential pressure pipeline is frozen according to the comparison result.

[0083] It should be noted that the above embodiments are only for more clearly illustrating the technical solutions of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope of the technical solutions of the present invention; other implementation methods will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A method for identifying icing in a pressure differential pipeline, characterized in that: The specific method is as follows: Get the original information when the pressure differential pipeline is frozen and not frozen; Perform normal distribution processing on the original information, and calculate the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data; The upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data are compared with the upstream ice melting judgment threshold and the downstream ice melting judgment threshold respectively; Based on the comparison results, determine whether the pressure difference pipeline is frozen.

2. The method for identifying icing in a pressure differential pipeline according to claim 1, characterized in that: The original information includes: Upstream pressure signal and downstream pressure signal.

3. The method for identifying icing in a differential pressure pipeline according to claim 2, characterized in that: The original information is processed for normal distribution, and the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data are calculated. The specific method is as follows: Acquire a first preset number of upstream and downstream pressure signals, and calculate the standard deviations of the upstream and downstream pressure signals respectively as first data; Obtain a second preset number of first data as above, and calculate the average of the first data as the second data; The third preset number of second data is obtained in the same manner as above, and the average of the second data is calculated as the upstream pressure difference pipeline input data and the downstream pressure difference pipeline input data.

4. The method for identifying icing in a pressure differential pipeline according to claim 3, characterized in that: The upstream ice melting judgment threshold and the downstream ice melting judgment threshold are calculated as follows: Get historical information on when the pressure differential pipeline is frozen and not frozen; Normalize the distribution of historical information; A two-dimensional data coordinate system is constructed according to the third data obtained by normalized distribution processing, wherein the abscissa of the two-dimensional data coordinate system is the pressure difference vibration amplitude information, and the two ordinates are respectively the sample distribution quantity information and the probability density information; The upstream ice-melting judgment threshold and the downstream ice-melting judgment threshold are calculated according to the two-dimensional data coordinate system.

5. The method for identifying icing in a pressure differential pipeline according to claim 1, characterized in that: To determine whether the pressure differential pipeline is frozen, the specific method is as follows: When the input data of the upstream differential pressure pipeline is less than the upstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the first freezing target number, it is judged that the upstream differential pressure pipeline is frozen; When the input data of the upstream pressure difference pipeline is greater than the upstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the first ice melting target number, it is determined that the upstream pressure difference pipeline is ice melting.

6. The method for identifying icing in a differential pressure pipeline according to claim 1, characterized in that: To determine whether the pressure differential pipeline is frozen, the specific method is as follows: When the input data of the downstream differential pressure pipeline is less than the downstream freezing judgment threshold, the count is increased by 1, and when the calculation reaches the second freezing target number, it is judged that the downstream differential pressure pipeline is frozen; When the downstream differential pressure pipeline input data is greater than the downstream ice melting judgment threshold, the count is increased by 1. When the calculation reaches the second ice melting target number, it is determined that the downstream differential pressure pipeline is ice melting.

7. The method for identifying icing in a differential pressure pipeline according to claim 5 or 6, characterized in that: When the upstream differential pressure pipeline or the downstream differential pressure pipeline is judged to be frozen, it is finally judged that the pipeline is frozen; When the upstream pressure difference pipeline and the downstream pressure difference pipeline are judged to be free of ice, it is finally judged that the pipeline is free of ice.

8. A pressure differential pipeline icing identification device, characterized in that: include: An information acquisition module is used to obtain the original information when the pressure difference pipeline is frozen or not frozen; The input calculation module performs normal distribution processing on the original information and calculates the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data; The judgment module compares the upstream differential pressure pipeline input data and the downstream differential pressure pipeline input data with the upstream thawing judgment threshold and the downstream thawing judgment threshold respectively; and judges whether the differential pressure pipeline is frozen according to the comparison result.

9. A storage medium, characterized in that: A plurality of instructions are stored, and a processor loads the instructions to execute the pressure differential pipeline icing identification method according to any one of claims 1 to 7.

10. A vehicle controller installed in a fuel vehicle or a hybrid vehicle, characterized in that: It comprises the pressure difference pipeline icing identification device as described in claim 8, and / or the storage medium as described in claim 9.

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