GPF cumulative carbon mass model correction method

Abstract

The present invention provides a method for calibrating a GPF carbon accumulation mass model, comprising the following steps: S1: obtaining a GPF reference mass W1; S2: running the engine under a first operating condition for 4-8 hours, and calculating the carbon accumulation W2 according to the GPF carbon accumulation mass model; S3: baking and regenerating the GPF to obtain the GPF actual mass W3; S4: calculating the actual carbon accumulation mass W4 according to the formula W4=W3-W1; S5: calculating the actual value of the constant C according to the formula C=W4 / W2, and substituting it into the GPF carbon accumulation mass model; S6: repeating steps S2-S5 until the difference between W4 and W2 is less than 0.01g, thereby adjusting the constant C. This scheme can calibrate the GPF carbon accumulation 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 GPF performance, predicting its service life, and optimizing the entire engine exhaust system.

Description

Technical Field

[0001] The present invention relates to the field of automobile testing technology, and in particular to a GPF carbon accumulation mass model correction method. Background Art

[0002] In modern automobile engine technology, gasoline particulate filters (GPFs) are widely used to reduce particulate matter emissions from gasoline engine exhaust.

[0003] Establishing an accurate carbon accumulation model is of great significance for evaluating the performance of GPF, predicting its 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 precise enough and cannot accurately reflect the actual carbon accumulation situation, bringing difficulties to the performance evaluation and optimization of GPF. Therefore, a method for calibrating the GPF carbon accumulation model is needed. Summary of the Invention

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

[0006] The present invention provides a GPF carbon accumulation mass model correction method, the GPF carbon accumulation mass model is:

[0007] ;

[0008] Among them, the initial value of constant C is set to 1, and the exhaust particulate matter weight rate is set to a certain value based on the experience of the engine manufacturer;

[0009] The GPF cumulative carbon mass model correction method comprises the following steps:

[0010] S1: Get GPF reference mass W1;

[0011] S2: The engine operates normally for 4-8 hours under the first operating condition, and the accumulated carbon mass W2 is calculated based on the GPF accumulated carbon mass model;

[0012] S3: bake and regenerate the GPF to obtain the actual mass of the GPF, recorded as W3;

[0013] S4: Calculate the actual accumulated carbon mass W4 according to the formula W4 = W3 - W1;

[0014] S5: Calculate the actual value of the constant C according to the formula C = W4 / W2 and bring it into the GPF carbon accumulation mass model;

[0015] S6: Repeat steps S2 to S5 until the difference between W4 and W2 is less than 0.01g to adjust the constant C.

[0016] According to one embodiment of the present invention, step S1 includes the following steps:

[0017] S1a: Get the temperature at the half depth position of the GPF carrier;

[0018] S1b: Install the modified GPF on the bench engine exhaust system and use a leak detector to check to ensure that the engine is leak-free.

[0019] S1c: Start the vehicle and check the engine idle stability. If no abnormalities are found, preheat the engine and GPF in the warm-up condition for 5-15 minutes.

[0020] S1d: After the warm-up is completed, the engine performs GPF carbon burning under carbon burning conditions;

[0021] S1e: Carry out carbon accumulation and carbon burning cycles, running for 40-80 minutes;

[0022] S1f: bake and regenerate the GPF to obtain the actual mass of the GPF;

[0023] S1g: Repeat steps S1d-S1f three times to obtain Wm1, Wm2, and Wm3 respectively;

[0024] S1h: When the data of Wm1, Wm2, and Wm3 are stable and the difference does not exceed 0.05g, calculate the average value W1 of the three. W1 is the GPF reference mass;

[0025] According to an embodiment of the present invention, in step S3 and step S1f, the GPF is baked and regenerated to obtain the actual quality of the GPF, including the following steps:

[0026] Preheat the muffle furnace to 300-400 degrees for 20-40 minutes until the temperature stabilizes;

[0027] Remove the GPF, place it in a muffle furnace, bake it at 300-400℃ for 1-3 hours, then take out the GPF and read the center temperature of the GPF;

[0028] When the center temperature of the GPF drops to 330±1℃, weigh the GPF once;

[0029] When the center temperature of the GPF drops to 320±1℃, weigh the GPF once;

[0030] When the center temperature of the GPF drops to 300±1℃, weigh the GPF once;

[0031] The actual mass of the GPF was obtained by taking the average of the three weighing results.

[0032] According to an embodiment of the present invention, step S6 further includes:

[0033] S7: Repeat steps S1d to S1h and bake and weigh the GPF until the error between the weighed mass and W1 is less than 0.02g;

[0034] S8: Run the engine normally for 4-8 hours, so that W2 is between 1-3g. Repeat steps S3 and S4 to obtain W4, and make sure that the difference between W2 and W4 does not exceed 0.01g. Bring the relevant data into the GPF carbon accumulation mass model for accuracy correction.

[0035] According to an embodiment of the present invention, step S8 further includes:

[0036] S9: Repeat steps S7 to S8, control W2 between 2g and 4g, complete several groups of tests, and bring the data into the GPF cumulative carbon mass model for accuracy correction.

[0037] According to an embodiment of the present invention, when the engine is operating normally in step S8, the exhaust temperature is lower than 700°C.

[0038] According to one embodiment of the present invention, step S1a includes:

[0039] Disconnect the front and rear connections of the GPF, weld a quick-change clamp set, and install a graphite composite gasket in the middle; pre-embed a ceramic interface temperature sensor to measure the temperature at 1 / 2 the depth of the GPF carrier.

[0040] 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%.

[0041] The carbon burning condition in step S1d is as follows: 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.

[0042] According to an embodiment of the present invention, before weighing the GPF in step S1 and step S3, a GPF bracket that can be placed on a balance is manufactured to place the GPF, thereby avoiding direct contact between the GPF and the balance during weighing.

[0043] According to an embodiment of the present invention, the first operating 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.

[0044] The beneficial effects of the present invention are:

[0045] The present invention provides a GPF carbon accumulation mass model correction method that can effectively correct the GPF carbon accumulation 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

[0046] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 1 is a flow chart of a method for correcting a GPF carbon accumulation mass model provided by an embodiment of the present invention;

[0048] Figure 2 Schematic diagram of the structure of the GPF bracket in an embodiment of the present invention;

[0049] Reference numerals: 100, GPF bracket; 101, base; 102, supporting portion; 103, placement slot. DETAILED DESCRIPTION

[0050] The following descriptions of the embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention may be implemented.

[0051] The present invention provides a GPF carbon accumulation mass model correction method for accurately calibrating the GPF carbon accumulation mass model to improve the accuracy of the GPF carbon accumulation mass model. Figure 1 The figure shows the flow chart of the GPF carbon mass model correction method. Figure 1 The GPF cumulative carbon mass model correction method is described in detail.

[0052] 1. Initial Preparation

[0053] (1.1) Modify the GPF to facilitate quick disassembly and assembly during the test

[0054] The front and rear connections of the GPF were disconnected, and a quick-change clamp set was welded in. A graphite composite gasket was installed in the middle, and a pre-embedded ceramic interface temperature sensor was used to measure the temperature at the halfway point of the GPF carrier in real time, providing a basis for subsequent precise control of operating conditions. The ceramic interface is resistant to high-temperature baking, preventing damage to the temperature sensor during baking.

[0055] (1.2) Making the GPF bracket

[0056] Make a GPF bracket 100 that can be placed on a balance. The structural diagram of the GPF bracket is as follows: Figure 2 As shown, it comprises a base 101 and a support 102 fixed to the top of base 101. The upper surface of support 102 has a placement slot 103 shaped to match the GPF's profile. The purpose of manufacturing GPF support 100 is to prevent direct contact between the GPF and the scale during weighing, preventing the GPF's high temperature from damaging the scale while ensuring weighing accuracy.

[0057] 2. Obtain GPF reference mass W1

[0058] (2.1) Installation and inspection

[0059] Install the modified GPF onto the test bench engine exhaust system and use a leak detector to ensure it's leak-free. Leak-free testing is essential for accurate test data. Leaks can affect the engine's intake and exhaust flow rates, further impacting carbon accumulation and model calibration accuracy.

[0060] (2.2) Starting and warming up the engine

[0061] Start the vehicle and check the engine idle stability. If no abnormalities are detected, warm up the engine and GPF for 5-15 minutes at an engine speed of 3000 rpm and a load of 30%. Specifically, in this embodiment, the warm-up time is 10 minutes. This step allows the engine and GPF to enter a stable operating state, creating stable conditions for subsequent operations.

[0062] (2.3) GPF carbon burning

[0063] After the warm-up is complete, adjust the engine speed to 3000 rpm, the air-fuel ratio to 1.1, and control the engine load to maintain a GPF center temperature of 710 ± 10°C. Perform GPF burnout under these operating conditions. This specific temperature, speed, and air-fuel ratio effectively removes existing carbon deposits from the GPF, paving the way for accurate measurement of new carbon accumulation.

[0064] (2.4) Carbon accumulation and carbon burning cycle

[0065] The carbon accumulation and burning cycle is repeated for 40-80 minutes. The burning conditions are the same as in step (2.3). Preferably, the carbon accumulation and burning cycle in this embodiment lasts for 60 minutes. By simulating multiple carbon accumulation and burning processes, the GPF's state is more closely aligned with actual usage.

[0066] (2.5) Baking and weighing process

[0067] The muffle furnace is preheated to 300-400 degrees, preferably, to 350 degrees, for 20-40 minutes until the temperature stabilizes, thereby ensuring the stability of the baking environment; preferably, the preheating time is 30 minutes.

[0068] Remove the GPF, place it in a muffle furnace, bake it at 350°C for 1-3 hours, then remove the GPF and read the center temperature of the GPF. Preferably, the baking time in this embodiment is 2 hours. During the use of the GPF, trapped particulate matter will gradually accumulate, resulting in increased backpressure and affecting engine performance. Therefore, regeneration is required, that is, burning the trapped particulate matter at high temperature to restore the performance of the GPF and ensure that subsequent weighing only reflects the mass of accumulated carbon. The muffle furnace can provide a high-temperature environment to simulate or accelerate this regeneration process.

[0069] When the center temperature of the GPF drops to 330 ± 1°C, the GPF is placed on an electronic balance equipped with a GPF stand and weighed, which is recorded as Wa.

[0070] When the center temperature of the GPF drops to 320 ± 1℃, the GPF is placed on an electronic balance equipped with a GPF bracket and weighed, which is recorded as Wb.

[0071] When the center temperature of the GPF drops to 300 ± 1°C, the GPF is placed on the electronic balance equipped with the GPF stand and weighed again, which is recorded as Wc.

[0072] (2.6) Weigh multiple times and take the average value

[0073] Take the average of the three weighing results (Wa, Wb, and Wc) to determine the GPF mass Wm1. Repeat this step twice to obtain Wm2 and Wm3. When the Wm1, Wm2, and Wm3 values are stable and differ by no more than 0.05g, calculate their average value, W1. This is the GPF reference mass. Taking the average value of multiple measurements can reduce measurement errors and ensure the accuracy of the reference mass.

[0074] 3. Calculate the accumulated carbon and adjust the constant C

[0075] (3.1) Calculate the cumulative carbon W2

[0076] Adjust the engine speed to 3000 rpm, the air-fuel ratio to 0.7, and control the engine load to keep the GPF center temperature below 700°C. Run for 4-8 hours; preferably, in this embodiment, run for 6 hours. Calculate the carbon accumulation W2 based on the GPF carbon accumulation mass model. The GPF carbon accumulation mass model is:

[0077]

[0078] Fuel consumption refers to the amount of fuel consumed by the engine per unit time, measured in liters per hour. The air-fuel ratio is the ratio of the mass of air entering the engine to the mass of fuel, a key parameter affecting engine performance and emissions. The constant C is initially set to 1, and the exhaust particulate matter weight rate is set to a certain value based on the engine manufacturer's experience, measured in grams per hour. Air density refers to the density of ambient air, measured in kilograms per cubic meter. Time refers to the time over which carbon particles accumulate in the GPF. Operating the engine under these specific operating conditions and calculating the accumulated carbon content according to the model formula are key steps in subsequent model calibration.

[0079] (3.2) Baking and weighing process to obtain GPF mass W3

[0080] The muffle furnace is preheated to 300-400 degrees Celsius for 20-40 minutes until the temperature stabilizes. Specifically, in this embodiment, the muffle furnace is preheated to 350 degrees Celsius for 30 minutes.

[0081] Remove the GPF, place it in a muffle furnace, bake it at 300-400°C for 1-3 hours, then take out the GPF and read the center temperature of the GPF. Preferably, in this embodiment, the baking temperature is 350°C and the baking time is 2 hours.

[0082] When the center temperature of the GPF drops to 330 ± 1°C, place the GPF on an electronic balance equipped with a GPF stand and weigh it once, which is recorded as Wa'.

[0083] When the center temperature of the GPF drops to 320 ± 1℃, place the GPF on an electronic balance equipped with a GPF stand and weigh it once, which is recorded as Wb'.

[0084] When the center temperature of the GPF drops to 300 ± 1℃, place the GPF on an electronic balance equipped with a GPF stand and weigh it once, which is recorded as Wc'.

[0085] The three weighing results Wa', Wb', and Wc' are averaged to obtain the GPF mass W3. This step is similar to the baking weighing process when obtaining the reference mass, and both are for accurately measuring the mass of the GPF.

[0086] (3.3) Calculate the actual cumulative carbon mass W4

[0087] The actual accumulated carbon mass W4 is calculated according to the formula W4 = W3 - W1, and the actual accumulated carbon amount is obtained by subtracting the accurately measured GPF mass from the reference mass.

[0088] (3.4) Calculate the actual value of the constant C and substitute it into the model

[0089] The actual value of the constant C is calculated according to the formula C = W4 / W2 and is brought into the GPF cumulative carbon mass model to make the model closer to the actual situation.

[0090] (3.5) Repeat the adjustment steps

[0091] Repeat the above steps from "calculating the accumulated carbon W2" to "calculating the actual value of constant C and substituting it into the model" (i.e., steps (3.1) - (3.5)) until the difference between W4 and W2 is less than 0.01g to adjust constant C. Repeating the adjustment multiple times can gradually optimize the value of constant C and improve the accuracy of the model.

[0092] 4. Further accuracy correction

[0093] (4.1) Repeated carbon accumulation, carbon burning and weighing

[0094] Repeat steps (2.3) through (2.6) (i.e., GPF carbon accumulation, carbon burnout cycle, bakeout, and weighing), and bakeout and weigh the GPF until the measured mass and W1 have an error of less than 0.02g. This step further ensures that the GPF is in a stable baseline state and eliminates interfering factors.

[0095] (4.2) Add test conditions

[0096] Run the engine for 6-10 hours, controlling engine speed, load, air-fuel ratio, and exhaust temperature below 700°C, until W2 is between 1-3g, preferably 2g in this example. Repeat steps (3.2)-(3.3) to obtain W4, ensuring that the difference between W2 and W4 does not exceed 0.01g. This data is then applied to the GPF carbon accumulation model for accuracy correction. Further optimize the model accuracy by conducting tests with varying operating times and carbon accumulation conditions.

[0097] (4.3) Correction for multiple trials

[0098] Repeat steps (4.1) and (4.2) (i.e., repeat the carbon burning and weighing steps, adding test conditions), controlling W2 between 2g and 4g, and complete several sets of tests. Then, apply the data to the GPF carbon accumulation model for accuracy correction. Multiple sets of tests allow for more comprehensive validation and correction of the model, ensuring high accuracy across a range of carbon accumulations.

[0099] Through the above specific embodiments, the GPF carbon accumulation mass model can be effectively calibrated 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.

[0100] It should be noted that although the present invention is disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. A method for calibrating a GPF carbon accumulation mass model. The GPF carbon accumulation mass model is: ； in, The initial value of the constant C is set to 1, and the exhaust particulate matter weight rate is set to a certain value based on the experience of the engine manufacturer; the method is characterized by comprising the following steps: S1: Get GPF reference mass W1; S2: The engine operates normally for 4-8 hours under the first operating condition, and the accumulated carbon mass W2 is calculated based on the GPF accumulated carbon mass model; S3: bake and regenerate the GPF to obtain the actual mass of the GPF, recorded 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 bring it into the GPF carbon accumulation mass model; S6: Repeat steps S2 to S5 until the difference between W4 and W2 is less than 0.01g to adjust the constant C.

2. The GPF carbon accumulation mass model correction method according to claim 1, characterized in that: Step S1 includes the following steps: S1a: Get the temperature at the half depth position of the GPF carrier; S1b: Install the modified GPF on the bench engine exhaust system and use a leak detector to check to ensure that the engine is leak-free. S1c: Start the vehicle and check the engine idle stability. If no abnormalities are found, preheat the engine and GPF in the warm-up condition for 5-15 minutes. S1d: After the warm-up is completed, the engine performs GPF carbon burning under carbon burning conditions; S1e: Carry out carbon accumulation and carbon burning cycles, running for 40-80 minutes; 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 0.05g, calculate the average value W1 of the three. W1 is the GPF reference mass.

3. The GPF carbon accumulation mass model correction method according to claim 2, characterized in that: In step S3 and step S1f, the GPF is baked and regenerated to obtain the actual mass of the GPF, which includes the following steps: Preheat the muffle furnace to 300-400 degrees for 20-40 minutes until the temperature stabilizes; Remove the GPF, place it in a muffle furnace, bake it at 300-400℃ for 1-3 hours, then take out the GPF and read the center temperature of the GPF; When the GPF center temperature drops to 330±1℃, weigh the GPF once; When the GPF center temperature drops to 320±1℃, weigh the GPF once; When the center temperature of the GPF drops to 300±1℃, weigh the GPF once; The actual mass of the GPF was obtained by taking the average of the three weighing results.

4. The GPF carbon accumulation mass model correction method according to claim 3, characterized in that: After step S6, the method further includes: S7: Repeat steps S1d to S1h and bake and weigh the GPF until the error between the weighed mass and W1 is less than 0.02g; S8: Run the engine normally for 4-8 hours, so that W2 is between 1-3g. Repeat steps S3 and S4 to obtain W4, and make sure that the difference between W2 and W4 does not exceed 0.01g. Bring the relevant data into the GPF carbon accumulation mass model for accuracy correction.

5. The GPF carbon accumulation mass model correction method according to claim 4, characterized in that: After step S8, the following steps are also included: S9: Repeat steps S7 to S8, control W2 between 2g and 4g, complete several groups of tests, and bring the data into the GPF cumulative carbon mass model for accuracy correction.

6. The GPF carbon accumulation mass model correction method according to claim 4, characterized in that: When the engine is operating normally in step S8, the exhaust temperature is lower than 700°C.

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

8. The GPF carbon accumulation mass model correction method according to claim 2, characterized in that: The warm-up condition in step S1c is: engine speed 3000 r / min, load 30%; The carbon burning condition in step S1d is as follows: 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 correction method according to claim 1, characterized in that: In step S1 and step S3, before weighing the GPF, a GPF bracket that can be placed on a balance is manufactured to place the GPF, thereby avoiding direct contact between the GPF and the balance during weighing.

10. The GPF carbon accumulation mass model correction method according to claim 1, characterized in that: The first operating 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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