Virtual calibration method for monitoring low engine DPF (diesel particulate filter) trapping efficiency

Abstract

The invention discloses a virtual calibration method for monitoring low DPF (diesel particulate filter) trapping efficiency of an engine. The virtual calibration method comprises the following steps: S101, acquiring parameters of the engine and a post-processing model; s102, building a virtual engine model according to the engine and post-processing model parameters; s103, establishing a protocol link between the virtual engine model and the calibration tool, and verifying whether the precision of the virtual engine model meets a preset precision target; s104, establishing a DPF simulation model according to the physical characteristics of the DPF; s105, DPF punching is simulated through the virtual calibration model, so that simulation of a DPF degraded part is consistent with that of an entity; and S106, DPF trapping efficiency low monitoring calibration is carried out according to the perfect DPF simulation model. The method has the advantages that the manufacturing process of degraded parts can be omitted, the DPF test efficiency is improved, and the test period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a virtual calibration method for monitoring low capture efficiency of a DPF of an engine. Background Art

[0002] The National VI OBD regulations require that for the input components of the engine system, the OBD system (full name On-Board Diagnostics for Vehicle Emission Control Systems, which refers to the on-board diagnostic system for emission control, it must have the function of identifying fault areas that may cause excessive emissions, and store this information in the form of fault codes in the electronic control unit memory, and at the same time light up the malfunction indicator light (MIL) to remind the driver) should at least monitor circuit faults and rationality diagnosis.

[0003] In order to meet the requirements of the National VI emission regulations, the DPF (particulate filter) technology route must be adopted. The DPF system has two functions: particle capture and particle regeneration. The diesel engine exhaust gas enters the channel with plugged holes at the bottom of the DPF and can only flow from the micropores on the channel wall to the adjacent channel with plugged holes at the front. The particles are filtered down by the channel wall, which is called the capture function of the DPF.

[0004] The National VI OBD regulations require that the components and performance parameters of the DPF system must be monitored, such as a decrease in DPF capture efficiency: when the DPF carrier is partially damaged or leaks, causing PM emissions to exceed the OBD limit, a fault is detected.

[0005] The current calibration idea is: first make a DPF degraded part to meet the OBD limit requirements (within the range of 25±20% mg / kWh). The general method is to punch holes on a fresh DPF, and then collect the DPF pressure difference characteristic curve of the degraded part for calibration. During the test, the cycle of making degraded parts is very long, involving DPF punching, emission testing, and then continuing to punch holes and test emissions until the emissions of the degraded parts meet regulatory requirements. In the entire test, the test cycle for making degraded parts accounted for more than 70%, making the test efficiency low. New test methods are urgently needed to shorten the test cycle and improve test efficiency.

[0006] Existing patent document CN115855512A discloses an OBD production method for degraded parts for demonstrating DPF low efficiency failure, which can well simulate the effects of aging and degraded parts of the DOC carrier obtained after actual vehicle tests of hundreds of thousands or even millions of kilometers, greatly shortening the preparation cycle of degraded parts of the DOC carrier, improving engine R&D efficiency, and reducing R&D costs.

[0007] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0008] The (main) purpose of the present invention is to propose a virtual calibration method for monitoring low engine DPF capture efficiency, which omits the manufacturing process of deteriorated parts and improves the DPF test efficiency.

[0009] To this end, the present invention proposes a virtual calibration method for monitoring low engine DPF capture efficiency.

[0010] Preferably, the present invention may also have the following technical features:

[0011] A virtual calibration method for monitoring low DPF capture efficiency of an engine comprises the following steps:

[0012] S101, obtaining engine and post-processing model parameters;

[0013] S102, building a virtual engine model according to engine and post-processing model parameters;

[0014] S103, establishing a protocol link between the virtual engine model and the calibration tool, and verifying whether the accuracy of the virtual engine model meets the preset accuracy target;

[0015] S104, establishing a DPF simulation model according to the physical characteristics of the DPF itself;

[0016] S105, simulating DPF punching through a virtual calibration model to make the simulation of the DPF deteriorated part consistent with the entity;

[0017] S106, performing DPF capture efficiency low monitoring calibration according to the improved DPF simulation model.

[0018] Furthermore, in step S101, based on the operating conditions of the engine and the post-processing and the characteristics under different working modes, test data for parameterization of the engine and the post-processing model are obtained; the engine and the post-processing model parameters include the physical and chemical characteristics of the engine and the post-processing.

[0019] Furthermore, in step S103, the initial calibration data of the calibration tool is written to the engine controller through the protocol; the virtual engine model is triggered to perform a simulation test, and it is determined whether the engine model meets the preset accuracy target based on the simulation test results.

[0020] Furthermore, the accuracy target includes the accuracy of various engine operating parameters.

[0021] Furthermore, in step S104, the physical properties of the DPF include the size, porosity and wall thickness of the DPF.

[0022] Compared with the prior art, the beneficial effects of the present invention include: by setting the accuracy target of the virtual engine model, it is possible to ensure that the operating parameters of the engine model and the physical engine under various operating conditions are consistent, and the results of virtual calibration on the virtual engine model are consistent with the structure of the physical engine calibration. By simulating DPF perforation through the virtual calibration model, the simulation of DPF deterioration parts is consistent with the physical, thereby improving the efficiency of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a control flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with specific implementations and with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its application.

[0025] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein like reference numerals refer to like parts unless otherwise specifically stated.

[0026] like Figure 1 A virtual calibration method for monitoring low engine DPF capture efficiency shown in the figure includes the following steps:

[0027] S101, obtaining engine and post-processing model parameters;

[0028] In step S101, based on the operating conditions of the engine and the post-processing and the characteristics under different working modes, test data for parameterization of the engine and the post-processing model are obtained; the engine and the post-processing model parameters include the physical and chemical characteristics of the engine and the post-processing.

[0029] S102, building a virtual engine model according to engine and post-processing model parameters;

[0030] S103, establishing a protocol link between the virtual engine model and the calibration tool, and verifying whether the accuracy of the virtual engine model meets the preset accuracy target;

[0031] In step S103, the initial calibration data of the calibration tool is written to the engine controller through the protocol; the virtual engine model is triggered to perform simulation test, and the engine model is judged whether it meets the preset accuracy target according to the simulation test results. Among them, the accuracy target includes the accuracy of various engine operating parameters, such as power, torque, intake volume, DPF pressure difference, etc. By setting the accuracy target of the virtual engine model, it can be ensured that the engine model and the physical engine have consistent operating parameters under various operating conditions, and the results of virtual calibration on the virtual engine model are consistent with the structure of physical engine calibration.

[0032] S104, establishing a DPF simulation model according to the physical properties of the DPF itself; the physical properties of the DPF include the size, porosity and wall thickness of the DPF.

[0033] S105, simulating DPF punching through a virtual calibration model (DPF simulation model) to make the simulation of the DPF deteriorated part consistent with the entity;

[0034] After the DPF simulation model is established, the DPF simulation model is used to simulate failure modes such as DPF perforation or air leakage, and then the DPF pressure difference and filtration efficiency are calculated through the new changes in the gas flow field inside the DPF. After the DPF simulation model completes the simulated perforation, the test calculates the DPF pressure difference and filtration efficiency based on the changes in the gas flow field inside the DPF after perforation. By simulating DPF perforation through the DPF simulation model, the process of making degraded parts can be omitted, thereby greatly improving the test efficiency. Moreover, the size of the simulated perforation can be adjusted according to the DPF characteristics required for the test, and it has strong adaptability.

[0035] S106, performing DPF capture efficiency low monitoring calibration according to the improved DPF simulation model.

[0036] The larger the DPF size, the smaller the porosity, and the thicker the wall, the greater the DPF pressure difference. The DPF simulation model simulates the DPF size, porosity, wall thickness and other parameters, and the area of ​​the DPF carrier is simulated to obtain the simulated DPF filtration efficiency and DPF pressure difference, and then simulates the degraded parts that meet the test requirements. This method can cope with various configurations and types of post-processing virtual calibration, which can effectively shorten the production cycle of degraded parts, improve work efficiency, and greatly shorten the engine bench development cycle.

[0037] Those skilled in the art will appreciate that numerous variations to the above description are possible, and that the examples and figures are intended only to describe one or more specific implementations.

[0038] Although what is considered as exemplary embodiments of the present invention has been described and described, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt specific situations to the teachings of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents that fall within the scope of the present invention.

Claims

1. A virtual calibration method for monitoring low engine DPF capture efficiency, characterized by: The steps include: S101, obtaining engine and post-processing model parameters; S102, building a virtual engine model according to engine and post-processing model parameters; S103, establishing a protocol link between the virtual engine model and the calibration tool, and verifying whether the accuracy of the virtual engine model meets the preset accuracy target; S104, establishing a DPF simulation model according to the physical characteristics of the DPF itself; S105, simulating DPF punching through a virtual calibration model to make the simulation of the DPF deteriorated part consistent with the entity; S106, performing DPF capture efficiency low monitoring calibration according to the improved DPF simulation model.

2. A virtual calibration method for monitoring low engine DPF capture efficiency as claimed in claim 1, characterized in that: In step S101, based on the operating conditions of the engine and the post-processing and the characteristics under different working modes, test data for parameterization of the engine and the post-processing model are obtained; the engine and the post-processing model parameters include the physical and chemical characteristics of the engine and the post-processing.

3. A virtual calibration method for monitoring low engine DPF capture efficiency as claimed in claim 1, characterized in that: In step S103, the initial calibration data of the calibration tool is written to the engine controller through the protocol; the virtual engine model is triggered to perform a simulation test, and it is determined whether the engine model meets the preset accuracy target based on the simulation test results.

4. A virtual calibration method for monitoring low engine DPF capture efficiency as claimed in claim 3, characterized in that: The accuracy target includes the accuracy of various engine operating parameters.

5. A virtual calibration method for monitoring low engine DPF capture efficiency as claimed in claim 1, characterized in that: In step S104, the physical properties of the DPF include the size, porosity and wall thickness of the DPF.

6. A virtual calibration method for monitoring low engine DPF capture efficiency as claimed in claim 1, characterized in that: In step S105, after the DPF simulation model is established, the DPF simulation model is used to simulate the DPF perforation or leakage failure mode, and then the DPF pressure difference and filtration efficiency are calculated through the new DPF internal gas flow field changes.

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