GPF carbon accumulation mass model correction method

Abstract

The invention provides a GPF carbon accumulation mass model correction method. The GPF carbon accumulation mass model correction method comprises the following steps: S1, obtaining GPF reference mass W1; s2, the engine normally operates for 4-8 hours under the first working condition, and accumulated carbon W2 is calculated according to a GPF accumulated carbon mass model; s3, the GPF is subjected to baking regeneration, and the actual mass W3 of the GPF is obtained; s4, calculating actual carbon accumulation mass W4 according to a formula W4 = W3-W1; s5, calculating an actual value of a constant C according to a formula C = W4 / W2, and substituting the actual value into a GPF carbon accumulation mass model; and S6, repeating the steps S2-S5 until the difference between the W4 and the W2 is less than 0.01 g so as to adjust the constant C. According to the scheme, the GPF carbon accumulation quality model can be corrected, the parameter C in the model can reflect the actual carbon accumulation condition more accurately, and a reliable basis is provided for evaluating the performance of the GPF, predicting the service life of the GPF and optimizing a whole engine exhaust system.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive testing, and particularly to a method for calibrating the GPF carbon accumulation mass model. Background Art

[0002] In modern automotive engine technology, gasoline particulate filters (GPFs) are widely used to reduce particulate emissions in the exhaust gases of gasoline engines.

[0003] Establishing an accurate carbon accumulation model is of great significance for evaluating the performance of GPFs, predicting their service life, and optimizing the entire engine exhaust system.

[0004] However, the parameter C in the existing GPF carbon accumulation model is generally set to 1, which is not accurate enough to accurately reflect the actual carbon accumulation situation, bringing difficulties to the performance evaluation and optimization of GPFs. Therefore, a method for calibrating the GPF carbon accumulation model is needed. Summary of the Invention

[0005] Based on the problems existing in the above-mentioned prior art, the present invention aims to solve the technical problem that the parameter in the carbon accumulation model of the gasoline particulate filter in the prior art is generally set to 1, which is not accurate enough to accurately reflect the actual carbon accumulation situation, bringing difficulties to the performance evaluation and optimization of the gasoline particulate filter.

[0006] The present invention provides a method for calibrating the GPF carbon accumulation mass model, and the GPF carbon accumulation mass model is: ; Among them, the initial value of the constant C is set to 1, and the exhaust particulate weight rate is set to a certain value according to the empirical value of the engine manufacturer; The method for calibrating the GPF carbon accumulation mass model includes the following steps: S1: Obtain the GPF reference mass W1; S2: The engine runs normally for 4 - 8 hours under the first working condition, and the carbon accumulation W2 is calculated according to the GPF carbon accumulation mass model; S3: Bake and regenerate the GPF to obtain the actual mass of the GPF, denoted as W3; S4: Calculate the actual carbon accumulation mass W4 according to the formula W4 = W3 - W1; S5: Calculate the actual value of the constant C according to the formula C = W4 / W2, and substitute it into the GPF carbon accumulation mass model; S6: Repeat steps S2 - S5 until the difference between W4 and W2 is less than 0.01 g to adjust the constant C.

[0007] According to an embodiment of the present invention, step S1 includes the following steps: S1a: Obtain the temperature at the 1 / 2 depth position of the GPF carrier; S1b: Install the modified GPF onto the exhaust system of the bench engine, and use leak detection liquid to check and ensure that the engine is airtight; S1c: Start the engine, check the engine idle stability. After there is no abnormality, preheat the engine and the GPF for 5 - 15 minutes under the warm-up condition; S1d: After the warm-up is completed, the engine performs GPF carbon combustion under the carbon combustion condition; S1e: Perform the carbon accumulation and carbon combustion cycles, and run for 40 - 80 min; S1f: Bake and regenerate the GPF to obtain the actual mass of the GPF; S1g: Repeat steps S1d - S1f three times to obtain Wm1, Wm2, and Wm3 respectively; S1h: When the data of Wm1, Wm2, and Wm3 are stable and the difference does not exceed 0.05 g, calculate the average value W1 of the three, and W1 is the reference mass of the GPF; According to an embodiment of the present invention, in step S3 and step S1f, baking and regenerating the GPF to obtain the actual mass of the GPF includes the following steps: Preheat the muffle furnace to 300 - 400 degrees and keep it for 20 - 40 min until the temperature is stable; Remove the GPF and put it into the muffle furnace. After baking at 300 - 400 °C for 1 - 3 hours, take out the GPF and read the central temperature of the GPF; When the central temperature of the GPF drops to 330 ± 1 °C, weigh the GPF once; When the central temperature of the GPF drops to 320 ± 1 °C, weigh the GPF once; When the central temperature of the GPF drops to 300 ± 1 °C, weigh the GPF once; Take the average of the three weighing results to obtain the actual mass of the GPF.

[0008] According to an embodiment of the present invention, after step S6, it further includes: S7: Repeat steps S1d~S1h, and bake and weigh the GPF until the error between the weighed mass and W1 is less than 0.02 g; S8: The engine runs normally for 4 - 8 hours to make W2 between 1 - 3 g. Repeat steps S3~S4 to obtain W4, and make the difference between W2 and W4 not exceed 0.01 g. Substitute the relevant data into the GPF carbon accumulation mass model for accuracy correction.

[0009] According to an embodiment of the present invention, after step S8, it further includes: S9: Repeat steps S7~S8, control W2 between 2 g - 4 g, complete several groups of tests, and substitute the data into the GPF carbon accumulation mass model for accuracy correction.

[0010] According to an embodiment of the present invention, when the engine is running normally in step S8, the exhaust temperature is lower than 700 °C.

[0011] According to an embodiment of the present invention, step S1a includes: Disconnect the connections at the front and rear of the GPF, weld the quick-change clamp set, and install a graphite composite gasket in the middle; embed a ceramic interface temperature sensor to measure the temperature at the 1 / 2 position of the GPF carrier depth.

[0012] According to an embodiment of the present invention, the warm-up condition in step S1c is that the engine speed is 3000 r / min and the load is 30%.

[0013] The carbon burning condition in step S1d is that the engine speed is 3000 r / min, the air-fuel ratio is 1.1, and the engine load is controlled so that the center temperature of the GPF is 710 ± 10 °C.

[0014] According to an embodiment of the present invention, in steps S1 and S3, before weighing the GPF, it further includes making a GPF bracket that can be placed on the balance to place the GPF, so as to avoid direct contact between the GPF and the balance during weighing.

[0015] According to an embodiment of the present invention, the first condition in step S2 is that the engine speed is 3000 r / min, the air-fuel ratio is 0.7, and the engine load is controlled so that the center temperature of the GPF is lower than 700 °C.

[0016] The beneficial effects of the present invention are: A method for correcting the GPF cumulative carbon mass model provided by the present invention can effectively correct the GPF cumulative carbon mass model, so that the parameter C in the model can more accurately reflect the actual carbon accumulation situation, providing a reliable basis for evaluating the performance of the GPF, predicting its service life, and optimizing the entire engine exhaust system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 is a flowchart showing a method for correcting the GPF cumulative carbon mass model provided by an embodiment of the present invention; Figure 2 is a structural diagram of the GPF bracket in an embodiment of the present invention; Reference Numerals: 100, GPF bracket; 101, base; 102, supporting part; 103, placement groove. Detailed Embodiment

[0019] The following descriptions of each embodiment refer to the attached drawings to illustrate specific embodiments in which the present invention can be implemented.

[0020] The present invention provides a method for calibrating the GPF cumulative carbon mass model to accurately calibrate the GPF cumulative carbon mass model and improve the accuracy of the GPF cumulative carbon mass model. As Figure 1 shown in the flow schematic diagram of the GPF cumulative carbon mass model calibration method, the GPF cumulative carbon mass model calibration method will be described in detail below in combination with Figure 1 for a detailed description.

[0021] 1. Initial Preparation (1.1) Modify the GPF to facilitate quick disassembly and assembly of the GPF during the test process Disconnect the front and rear connections of the GPF, weld on a quick-change clamp set, install a graphite composite gasket in the middle, and embed a ceramic interface temperature sensor to measure the temperature at the 1 / 2 position of the GPF carrier depth in real time, providing a basis for accurately controlling the working conditions in the follow-up. The ceramic interface is resistant to high-temperature baking to avoid damaging the temperature sensor during the baking process.

[0022] (1.2) Fabricate the GPF bracket Fabricate a GPF bracket 100 that can be placed on a balance. The structural schematic diagram of the GPF bracket is as Figure 2 shown. It includes a base 101 and a supporting part 102 fixed to the top of the base 101. The upper surface of the supporting part 102 has a placement groove 103 whose shape matches the outer shape of the GPF. The purpose of fabricating the GPF bracket 100 is to prevent the GPF from directly contacting the balance during weighing, prevent the high temperature of the GPF from damaging the balance, and ensure the accuracy of weighing.

[0023] 2. Obtain the GPF reference mass W1 (2.1) Installation and Inspection Install the modified GPF onto the exhaust system of the bench engine and use a leak detection liquid to check to ensure that the engine is airtight. Ensuring that the engine is airtight is the basis for ensuring the accuracy of subsequent test data. Air leakage will affect the intake and exhaust gas flow of the engine, thereby affecting the carbon accumulation situation and the accuracy of model calibration.

[0024] (2.2) Start the vehicle and warm up the engine Start the vehicle and check the engine idle stability. After there is no abnormality, warm up the engine and GPF for 5 - 15 minutes. The working condition is the engine speed of 3000 r / min and the load of 30%. Specifically, in this embodiment, the warm-up time is 10 minutes. This step can make the engine and GPF enter a stable working state and create stable conditions for subsequent operations.

[0025] (2.3)GPF Carbon Burning After the warm-up is completed, adjust the engine speed to 3000 r / min, the air-fuel ratio to 1.1, control the engine load to make the GPF center temperature 710 ± 10℃, and perform GPF carbon burning under this working condition. Under these specific temperature, speed and air-fuel ratio conditions, the existing carbon deposits in the GPF can be effectively removed, preparing for the subsequent accurate measurement of the new accumulated carbon amount.

[0026] (2.4)Accumulated Carbon and Carbon Burning Cycle Perform the accumulated carbon and carbon burning cycle for 40 - 80 minutes. The carbon burning working condition is the same as that in step (2.3); preferably, in this embodiment, the accumulated carbon and carbon burning cycle duration is 60 minutes. By simulating multiple accumulated carbon and carbon burning processes, the state of the GPF is closer to the actual usage situation.

[0027] (2.5)Baking and Weighing Process Preheat the muffle furnace to 300 - 400 degrees, preferably 350 degrees, and keep it for 20 - 40 minutes until the temperature is stable, ensuring the stability of the baking environment; preferably, the preheating duration is 30 minutes.

[0028] Remove the GPF, put it into the muffle furnace, take out the GPF after baking at 350℃ for 1 - 3 hours, and read the center temperature of the GPF; preferably, in this embodiment, the baking duration is 2 hours. During the use of the GPF, the trapped particulate matter will gradually accumulate, resulting in an increase in back pressure and affecting the engine performance. Therefore, regeneration is required, that is, burning the trapped particulate matter through high temperature to restore the performance of the GPF and ensure that the subsequent weighing only reflects the mass of the accumulated carbon. The muffle furnace can provide a high-temperature environment for simulating or accelerating this regeneration process.

[0029] When the GPF center temperature drops to 330 ± 1℃, place the GPF on an electronic balance equipped with a GPF bracket and weigh it, denoted as Wa.

[0030] When the GPF center temperature drops to 320 ± 1℃, also place the GPF on an electronic balance equipped with a GPF bracket and weigh it, denoted as Wb.

[0031] When the central temperature of the GPF drops to 300 ± 1°C, weigh the GPF on an electronic balance equipped with a GPF bracket again and record it as Wc.

[0032] (2.6)Take the average value by weighing multiple times Take the average of the three weighing results of Wa, Wb, and Wc to obtain the GPF mass Wm1. Repeat the above steps twice to get Wm2 and Wm3. When the data of Wm1, Wm2, and Wm3 are stable and the difference does not exceed 0.05 g, calculate the average value W1 of the three. W1 is the reference mass of the GPF. Taking the average value by multiple measurements can reduce measurement errors and ensure the accuracy of the reference mass.

[0033] 3. Calculate the accumulated carbon and adjust the constant C (3.1)Calculate the accumulated carbon W2 Adjust the engine speed to 3000 r / min, the air-fuel ratio to 0.7, control the engine load to keep the central temperature of the GPF below 700°C, and run for 4 - 8 hours; preferably, in this embodiment, run for 6 hours. Calculate the accumulated carbon W2 according to the GPF accumulated carbon mass model. The GPF accumulated carbon mass model is:

[0034] Among them, the fuel consumption refers to the amount of fuel consumed by the engine per unit time, with the unit of liters per hour; the air-fuel ratio refers to the ratio of the mass of air entering the engine to the mass of fuel, which is an important parameter affecting the performance and emissions of the engine; the initial value of the constant C is set to 1, the exhaust particulate matter weight rate is set to a certain value according to the empirical value of the engine manufacturer, with the unit of grams per hour; the air density refers to the density of ambient air, with the unit of kilograms per cubic meter; the time refers to the time for the GPF to accumulate carbon particles. Operating the engine under this specific working condition and calculating the accumulated carbon amount according to the model formula is a key step for subsequent model calibration.

[0035] (3.2)Obtain the GPF mass W3 through the baking and weighing process Preheat the muffle furnace to 300 - 400 degrees and keep it for 20 - 40 min until the temperature is stable. Specifically, in this embodiment, the preheating temperature of the muffle furnace is 350°C and it lasts for 30 min.

[0036] Remove the GPF and put it into the muffle furnace. After baking at 300 - 400°C for 1 - 3 hours, take out the GPF and read the central temperature of the GPF. Preferably, in this embodiment, the baking temperature is 350°C and the baking duration is 2 hours.

[0037] When the central temperature of the GPF drops to 330 ± 1°C, weigh the GPF on an electronic balance equipped with a GPF bracket once and record it as Wa'.

[0038] When the central temperature of the GPF drops to 320 ± 1°C, weigh the GPF once on an electronic balance equipped with a GPF bracket, and record it as Wb'.

[0039] When the central temperature of the GPF drops to 300 ± 1°C, weigh the GPF once on an electronic balance equipped with a GPF bracket, and record it as Wc'.

[0040] Take the average of the three weighing results Wa', Wb', and Wc' to obtain the GPF mass W3. This step is similar to the baking and weighing process for obtaining the reference mass, both aiming to accurately measure the mass of the GPF.

[0041] (3.3)Calculate the actual carbon accumulation mass W4 Calculate the actual carbon accumulation mass W4 according to the formula W4 = W3 - W1. The actual carbon accumulation amount is obtained by subtracting the reference mass from the accurately measured GPF mass.

[0042] (3.4)Calculate the actual value of the constant C and substitute it into the model Calculate the actual value of the constant C according to the formula C = W4 / W2, and substitute it into the GPF carbon accumulation mass model to make the model closer to the actual situation.

[0043] (3.5)Repeat the adjustment steps Repeat the above steps from "calculate carbon accumulation W2" to "calculate the actual value of the constant C and substitute it into the model" (i.e., steps (3.1) - (3.5)) until the difference between W4 and W2 is less than 0.01 g to adjust the constant C. Repeating the adjustment multiple times can gradually optimize the value of the constant C and improve the accuracy of the model.

[0044] 4. Further precision correction (4.1)Repeat carbon accumulation, carbon burning, and weighing Repeat steps (2.3) - (2.6) (i.e., GPF carbon accumulation, carbon burning cycle, baking and weighing, etc.), and bake and weigh the GPF until the weighing mass has an error of less than 0.02 g from W1. This step further ensures that the GPF is in a stable reference state and excludes interference factors.

[0045] (4.2)Increase test conditions Run the engine, control the engine speed, load, air-fuel ratio, and keep the exhaust temperature below 700 °C. Operate for 6 - 10 hours to make W2 between 1 - 3 g, preferably 2 g in this embodiment. Repeat steps (3.2) - (3.3) to obtain W4, and ensure that the difference between W2 and W4 does not exceed 0.01 g. Substitute the relevant data into the GPF cumulative carbon mass model for accuracy correction. Through experiments under different operating times and carbon accumulation amounts, further optimize the model accuracy.

[0046] (4.3)Multi-group test correction Repeat steps (4.1) - (4.2) (i.e., repeat the carbon burning and weighing, and increasing test conditions steps), control W2 between 2 g - 4 g, complete several groups of tests, and substitute the data into the GPF cumulative carbon mass model for accuracy correction. Multi-group tests can more comprehensively verify and correct the model, enabling it to maintain high accuracy within different carbon accumulation ranges.

[0047] Through the above specific embodiments, the GPF cumulative carbon mass model can be effectively corrected, enabling the parameter C in the model to more accurately reflect the actual carbon accumulation situation, providing a reliable basis for evaluating the performance of the GPF, predicting its service life, and optimizing the entire engine exhaust system.

[0048] It should be noted that although the present invention is disclosed as above with specific embodiments, the above embodiments are not intended to limit the present invention. Those of ordinary skill in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is subject to the scope defined by the claims.

Claims

1. A method for calibrating the GPF carbon accumulation mass model. The GPF carbon accumulation mass model is as follows: ； Among them, The initial value of the constant C is set to 1, and the exhaust particulate matter weight rate is set to a certain value according to the empirical value of the engine manufacturer. It is characterized by the following steps: S1: Obtain the GPF reference mass W1. S2: The engine operates normally for 4 - 8 hours under the first working condition, and the accumulated carbon W2 is calculated according to the GPF carbon accumulation mass model. S3: Bake and regenerate the GPF to obtain the actual mass of the GPF, denoted as W3. S4: Calculate the actual accumulated carbon mass W4 according to the formula W4 = W3 - W1. S5: Calculate the actual value of the constant C according to the formula C = W4 / W2, and substitute it into the GPF carbon accumulation mass model. S6: Repeat steps S2 - S5 until the difference between W4 and W2 is less than 0.01 g to adjust the constant C.

2. The GPF cumulative carbon mass model calibration method according to claim 1, wherein Step S1 includes the following steps: S1a: Obtain the temperature at the 1 / 2 depth position of the GPF carrier. S1b: Install the modified GPF on the exhaust system of the bench engine, and use a leak detection liquid to check to ensure that the engine does not leak air. S1c: Start the vehicle, check the engine idle stability. After there is no abnormality, preheat the engine and the GPF for 5 - 15 minutes under the warm-up working condition. S1d: After the warm-up is completed, the engine performs GPF carbon burning under the carbon burning working condition. S1e: Perform the accumulated carbon and carbon burning cycles, and run for 40 - 80 min. S1f: Bake and regenerate the GPF to obtain the actual mass of the GPF. S1g: Repeat steps S1d - S1f three times to obtain Wm1, Wm2, and Wm3 respectively. S1h: When the data of Wm1, Wm2, and Wm3 are stable and the difference does not exceed 0.05 g, find the average value of the three, W1, and W1 is the GPF reference mass.

3. The GPF cumulative carbon mass model calibration method according to claim 2, wherein In step S3 and step S1f, when baking and regenerating the GPF to obtain the actual mass of the GPF, it includes the following steps: Preheat the muffle furnace to 300 - 400 degrees and keep it for 20 - 40 min until the temperature is stable. Remove the GPF and put it into the muffle furnace. Bake the GPF at 300 - 400 °C for 1 - 3 hours, then take out the GPF and read the central temperature of the GPF. When the central temperature of the GPF drops to 330 ± 1 °C, weigh the GPF once. When the central temperature of the GPF drops to 320 ± 1 °C, weigh the GPF once. When the central temperature of the GPF drops to 300 ± 1 °C, weigh the GPF once. Take the average value of the three weighing results to obtain the actual mass of the GPF.

4. The GPF carbon accumulation mass model calibration method according to claim 3, characterized in that After step S6, it also includes: S7: Repeat steps S1d - S1h, and bake and weigh the GPF until the weighing mass error from W1 is less than 0.02 g. S8: The engine operates normally for 4 - 8 hours to make W2 between 1 - 3 g. Repeat steps S3 - S4 to obtain W4, and make the difference between W2 and W4 not exceed 0.01 g. Substitute the relevant data into the GPF carbon accumulation mass model for accuracy calibration.

5. The GPF cumulative carbon mass model calibration method according to claim 4, wherein After step S8, it also includes: S9: Repeat steps S7 - S8, control W2 between 2 g - 4 g, complete several groups of tests, and substitute the data into the GPF carbon accumulation mass model for accuracy calibration.

6. The GPF cumulative carbon mass model calibration method according to claim 4, wherein When the engine is running normally in step S8, the exhaust temperature is lower than 700 °C.

7. The GPF cumulative carbon mass model calibration method according to claim 2, wherein Step S1a includes: Disconnect the front and rear connections of the GPF, weld the quick-change clamp set, and install a graphite composite gasket in the middle; embed a ceramic interface temperature sensor to measure the temperature at the 1 / 2 position of the GPF carrier depth.

8. The GPF cumulative carbon mass model calibration method according to claim 2, wherein The warm-up condition in step S1c is that the engine speed is 3000 r / min and the load is 30%; The carbon burning condition in step S1d is that the engine speed is 3000 r / min, the air-fuel ratio is 1.1, and the engine load is controlled so that the GPF center temperature is 710 ± 10 °C.

9. The GPF carbon accumulation mass model calibration method according to claim 1, characterized in that In steps S1 and S3, before weighing the GPF, it also includes making a GPF support that can be placed on the balance to place the GPF, thus avoiding direct contact between the GPF and the balance during weighing.

10. The GPF carbon accumulation mass model calibration method according to claim 1, wherein, The first condition in step S2 is that the engine speed is 3000 r / min, the air-fuel ratio is 0.7, and the engine load is controlled so that the GPF center temperature is lower than 700 °C.

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