Ash sample preparation method

Abstract

The present invention discloses a method for making an ash sample, comprising the steps of: S1, determining the ash target value of a particle collector; S2, accumulating ash through a bench experiment to make an ash sample; S3, verifying the ash sample. The ash sample making method of the present invention can actually reflect the influence of actual ash on the particle collector, and has a short production cycle and is easy to implement, and the ash sample has good repeatability.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile exhaust treatment, and in particular, relates to a method for making an ash sample. Background Art

[0002] The "Light Vehicle Pollutant Emission Limits and Strategy Methods (China Phase VI)" is the light vehicle National VI standard and was officially released on December 23, 2016. Compared with the National V standard, the National VI standard has the following major changes after the promulgation of the regulations: the Type I test cycle has been changed, the pollutant emission limits have been tightened, the requirements for measuring the number of particulate matter emitted by gasoline vehicles have been added, and the actual driving pollutant emission (RDE) experiment has been changed to the Type II experiment. In order to meet the changes in this standard, the OEMs generally adopt the technical route of the particulate filter to meet the regulatory requirements. However, after adding the particulate filter, since the engine oil contains sulfates, hydrochlorides, calcium, zinc, magnesium and other compounds, they will accumulate in the particulate filter as the mileage increases. Long mileage will increase the back pressure of the particulate filter, resulting in insufficient power and high temperature during the regeneration of the carbon particles in the particulate filter. For this reason, the electronic control system needs to calibrate the ash content in the particulate filter before the power is insufficient to avoid this problem. When calibrating the electronic control system, the OEM needs to provide a particulate filter ash sample. If the ash samples of the particle collector are produced by the carrier manufacturer, there will be problems such as long cycle, high cost and limited resources. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an ash sample production method, the purpose of which is to shorten the production cycle.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: an ash sample preparation method, comprising the steps of:

[0005] S1. Determine the target ash value of the particle collector;

[0006] S2. Accumulate ash content through bench test and make ash samples;

[0007] S3. Verify the ash content of the sample.

[0008] The step S2 comprises:

[0009] S201, taking quantitative ash content;

[0010] S202, drying ash;

[0011] S203, particle collector benchmark quality confirmation;

[0012] S204, particle collector soot blowing;

[0013] S205, the rack accumulated particle collector ash;

[0014] S206, weigh after accumulation, and record the accumulated mass of ash;

[0015] S207. Repeat steps S204 to S206 for multiple times until the cumulative ash mass reaches the target ash value of the particle collector, and the ash sample production is completed.

[0016] In step S202, the ash is placed in a drying furnace, dried at a set temperature for a first set time, and then taken out.

[0017] The drying furnace is a muffle furnace, the set temperature is 350° C., and the first set time is 20 minutes.

[0018] The step S203 includes:

[0019] S2031. After weighing the new particulate filter, install the new particulate filter in the exhaust system of the test bench;

[0020] S2032, the engine is running, heating the particulate filter;

[0021] S2033, operating the particle collector at the highest temperature point and the maximum flow point for a second set time;

[0022] S2034, the engine runs according to the set program;

[0023] S2035, under the first set condition, the particulate trap is regenerated for a third set time;

[0024] S2036, removing the particle collector, and then weighing the particle collector;

[0025] S2037, installing the particulate trap in the exhaust system again, and regenerating the particulate trap for a fourth set time under the second set condition;

[0026] S2038, removing the particulate collector, and then weighing the particulate collector again;

[0027] S2039. Calculate the reference mass of the particle collector.

[0028] The step S205 includes:

[0029] S2051. Install a particulate collector in the exhaust system of the test bench, and blow a set mass of ash into the particulate collector;

[0030] S2052, the engine is operated under the dust accumulation condition;

[0031] S2053. The engine is operated under carbon removal conditions.

[0032] In the step S206, the particle collector is placed in a drying furnace, and after being kept warm, the particle collector is taken out and weighed, and the accumulated mass of ash is recorded.

[0033] In the step S2052, under the ash accumulation condition, the engine speed is 5000 rpm, and the engine runs at 100% load for 1 hour; in the step S2053, under the carbon removal condition, the engine speed is 3500 rpm, the engine torque is 150 Nm, the air-fuel ratio is 1.1, and the engine runs for 0.5 hours.

[0034] The ash sample preparation method of the present invention can actually reflect the influence of actual ash content on the particle collector, and has a short preparation cycle and is easy to implement. At the same time, the ash sample has good repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of the ash sample preparation method of the present invention;

[0036] Figure 2 The effect of ash content on GPF carbon loading is prohibited by oil cut-off;

[0037] Figure 3 is the effect of ash content on GPF pressure difference (soot = 0g);

[0038] Figure 4 The effect of ash content on GPF pressure difference (soot=7g). DETAILED DESCRIPTION

[0039] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0040] like Figure 1 As shown, the present invention provides a method for making an ash sample, comprising the following steps:

[0041] S1. Determine the target ash value of the particle collector;

[0042] S2. Accumulate ash content through bench test and make ash samples;

[0043] S3. Verify the ash content of the sample.

[0044] Specifically, in the above step S1, there are two methods for calculating the target value of the ash content of the particulate filter, one of which is the vehicle fuel consumption calculation method, and the other is the bench fuel consumption calculation method.

[0045] As shown in Table 1, the parameters for calculating the target ash content of the particulate filter using the vehicle fuel consumption calculation method include the engine oil fuel consumption mass fraction (average value), average fuel consumption, average fuel density (#93) and equivalent mileage value.

[0046] Table 1

[0047] Input conditions Recommended value Engine oil fuel consumption mass fraction (average value) 0.067％ Average fuel consumption L / 100 km 7.8 Average fuel density (#93) g / L 725 Equivalent mileage / km 240000

[0048] Set the engine oil fuel consumption mass fraction (average value) to C1, the average fuel consumption to D1, the average fuel density (#93) to E1, the average engine oil consumption to F1, the equivalent mileage value / kilometer to G1, the engine oil consumption to H1, the recommended ash value (8% ash calculation) to I1, the correction coefficient to J1, the constant to L1, and the particulate filter ash target value to K1.

[0049] K1=I1*J1,I1=H1*L1,H1=G1 / 100*F1,F1=C1*D1*E1。In this embodiment, C1=0.067%,D1=7.8L / 100km,E1=725g / L,F1=3.78885g / 100km,G1=240000km,H1=9093.24g。L1 and J1 are both constants, according to experience, L1=0.008,J1=1.2。Finally, I1=72.74592g,K1=87g。

[0050] As shown in Table 2, the parameters for calculating the target ash content of the particulate filter using the bench fuel consumption calculation method include full-speed and full-load oil consumption, maximum vehicle speed, average fuel density (#93), recommended ash content, equivalent mileage value, and the vehicle mileage coefficient corresponding to the bench running time.

[0051] Table 2

[0052] Input conditions Recommended value Full speed and full load oil consumption g / h 37.33 Maximum speed (Km / h) 140 Average fuel density (#93) g / L 725 Recommended ash value 8％ Test bench operation time corresponds to vehicle mileage coefficient 7

[0053] Set the maximum vehicle speed to B2, the converted mileage value to C2, the equivalent vehicle mileage of 24W kilometers bench running time to D2, the bench running time corresponding to the vehicle mileage coefficient to E2, the actual bench running time to F2, the full-speed and full-load oil consumption to G2, the equivalent vehicle mileage of 24W oil consumption mass to H2, the theoretical ash calculation amount (8% ash calculation) to I2, the correction coefficient to J2, and the particulate filter ash target value to K2.

[0054] K2=I2*J2,I2=H2*L2 / 100,F2=D2 / E2,D2=C2 / B2。In this embodiment, B2=140Km / h,C2=240000km,D2=1714.285714,G2=37.33333333。E2,L2 and J2 are all constants. According to experience, E2=7,L2=0.8,J2=1.2。Finally, I2=73.1429g,K1=87.77143g。

[0055] Therefore, in the above step S1, the target value of the particle collector ash content is determined to be 87g, and 87 ash content needs to be accumulated in the particle collector. Then in step S2, a bench is built, and the ash content is accumulated according to the accumulated ash content specification requirements to form an ash content sample. Finally, in step S3, after the ash content is accumulated, the particle collector ash content sample is calibrated, and the effect of the particle collector ash content on the particle collector is obtained through calibration, completing the verification work.

[0056] The above step S2 comprises:

[0057] S201, taking quantitative ash content;

[0058] S202, drying ash;

[0059] S203, particle collector benchmark quality confirmation;

[0060] S204, particle collector soot blowing;

[0061] S205, the rack accumulated particle collector ash;

[0062] S206, weigh after accumulation, and record the accumulated mass of ash;

[0063] S207. Repeat steps S204 to S206 for multiple times until the cumulative ash mass reaches the target ash value of the particle collector, and the ash sample production is completed.

[0064] In the above step S201, a certain amount of ash is weighed on an ash weighing device (ash model is ISO 12103-1, A4) at room temperature, and the weighed ash is 100g. The weighing device is a balance scale, and the surface of the balance scale must be smooth. A piece of paper can be placed on the surface of the balance scale and divided by "zero".

[0065] In the above step S202, since the ash is in the container and contains a certain amount of water, the ash needs to be dried. First, the ash is placed in a steel pipe, and then the steel pipe containing the ash is placed in a drying furnace, dried at a set temperature for a first set time, and then taken out.

[0066] In this embodiment, the drying furnace is a muffle furnace, the set temperature is 350° C., and the first set time is 20 minutes to ensure the removal of moisture contained in the ash.

[0067] The above step S203 includes:

[0068] S2031. After weighing the new particulate filter, install the new particulate filter in the engine exhaust system;

[0069] S2032, the engine is running, heating the particulate filter;

[0070] S2033, operating the particle collector at the highest temperature point and the maximum flow point for a second set time;

[0071] S2034, the engine runs according to the set program;

[0072] S2035, under the first set condition, the particulate trap is regenerated for a third set time;

[0073] S2036, removing the particle collector, and then weighing the particle collector;

[0074] S2037, installing the particulate trap in the exhaust system again, and regenerating the particulate trap for a fourth set time under the second set condition;

[0075] S2038, removing the particulate collector, and then weighing the particulate collector again;

[0076] S2039. Calculate the reference mass of the particle collector.

[0077] In the above step S2031, before the bench test, a new particulate filter is installed in the engine exhaust system on the bench. The bench is provided with components such as the engine, the particulate filter, the exhaust temperature sensor and the pressure sensor.

[0078] In the above step S2032, the engine is started, the engine speed is set to 2500 rpm, the engine runs at 40-50% load, and is heated for a period of time, and then the engine runs at 70% load to heat the particulate filter.

[0079] In the above step S2033, the second set time is 30 minutes.

[0080] In the above step S2034, the engine speed is first set to 1500 rpm, and the engine runs at 80% load for 10 minutes, then the engine speed is increased to 4500 rpm, and the engine runs at 80% load for another 10 minutes. This process is a complete control process for the engine, and this process is repeated multiple times, and when the engine runs for 6 hours, the next step is executed.

[0081] In the above step S2035, the first setting condition includes the air-fuel ratio and the exhaust temperature, the air-fuel ratio is 1.1, and the exhaust temperature is high. The third setting time is 2h, and the particulate filter is regenerated for 2h under the conditions of high exhaust temperature and air-fuel ratio of 1.1. In the above step S2036, the particulate filter is removed from the engine exhaust system, and then the removed particulate filter is weighed, and the particulate filter needs to be weighed three times at different temperatures. When the temperature of the particulate filter is 350℃, the particulate filter is weighed for the first time; when the temperature of the particulate filter is 300℃, the particulate filter is weighed for the second time; when the temperature of the particulate filter is 280℃, the particulate filter is weighed for the third time; finally, the average value of the three weighing results is calculated as the first mass value.

[0082] In the above step S2037, the particulate filter is installed again in the engine exhaust system on the test bench, and the engine is running. The second setting condition includes the air-fuel ratio and the exhaust temperature, the air-fuel ratio is 1.1, and the exhaust temperature is high. The fourth setting time is 2 hours, and the particulate filter is regenerated for 2 hours under the conditions of high exhaust temperature and air-fuel ratio of 1.1.

[0083] In the above step S2038, the particulate trap is removed from the engine exhaust system, and then the removed particulate trap is weighed, and the particulate trap needs to be weighed three times at different temperatures. When the temperature of the particulate trap is 315°C, the particulate trap is weighed for the first time; when the temperature of the particulate trap is 300°C, the particulate trap is weighed for the second time; when the temperature of the particulate trap is 290°C, the particulate trap is weighed for the third time; finally, the average of the three weighing results is calculated as the second mass value.

[0084] In the above step S2039, the reference mass of the particulate trap is calculated, and the reference mass of the particulate trap is the average of the first mass value obtained in step S2036 and the second mass value obtained in step S2038.

[0085] In the above step S204, 20g of ash is brushed into the particle collector so that a large amount of ash adheres to the wall of the particle collector, and then a dry brush is used to evenly process the ash adhered to the particle collector. After shaking the particle collector, the ash enters the pores of the particle collector.

[0086] Since the ash is relatively dry, when the ash is accumulated on the test bench, the ash should be accumulated under the condition with the maximum oil consumption first. Since carbon accumulation will occur when the ash is accumulated, the carbon burning condition should be performed after the ash accumulation condition is completed to ensure that the ash accumulation quality result is accurate. To this end, the above step S205 includes:

[0087] S2051, installing the particulate collector after soot blowing in the engine exhaust system on the test bench, and blowing ash having a set mass into the particulate collector;

[0088] S2052, the engine is operated under the dust accumulation condition;

[0089] S2053. The engine is operated under carbon removal conditions.

[0090] In the above step S2051, 20 g of ash is blown into the particulate trap, and the particulate trap with 20 g of ash blown into it is installed in the engine exhaust system on the bench.

[0091] In the above step S2052, under the ash accumulation condition, the engine speed is 5000 rpm, and the engine runs at 100% load for 1 hour.

[0092] In the above step S2053, under the carbon removal condition, the engine speed is 3500 rpm, the engine torque is 150 Nm, the air-fuel ratio is 1.1, and the engine runs for 0.5 hours.

[0093] In the above step S206, the particulate filter is removed from the engine exhaust system, and then the particulate filter is placed in a drying furnace. After being kept warm for a period of time, the particulate filter is taken out and weighed, and the ash cumulative mass is recorded. The ash cumulative mass calculated each time is the difference between the total mass of the particulate filter obtained in this step and the reference mass of the particulate filter.

[0094] In the above step S206, the drying furnace used is a muffle furnace. The particle collector is weighed, and the particle collector needs to be weighed three times at different temperatures. When the temperature of the particle collector is 315°C, the particle collector is weighed for the first time; when the temperature of the particle collector is 300°C, the particle collector is weighed for the second time; when the temperature of the particle collector is 290°C, the particle collector is weighed for the third time. Record the mass of the particle collector after each weighing, calculate the average of the three weighing results, take the average as the total mass of the particle collector, and then calculate the cumulative mass of ash, which is the difference between the total mass of the particle collector and the reference mass of the particle collector.

[0095] In the above step S207, steps S204 to S206 are repeatedly executed multiple times. In the above step S204, 20g of ash is brushed into the particle collector each time, and then steps S205 and S206 are executed. In step S207, it is determined whether the cumulative mass of ash reaches the target value of ash in the particle collector. When the cumulative mass of ash reaches the target value of ash in the particle collector, an ash sample is obtained, and then the next step S3 can be executed; otherwise, steps S204 to S206 are executed again.

[0096] In the above S3, the ash sample is verified, and it is necessary to analyze the influence of the particulate filter ash content on the prohibition of oil cut-off and the influence of the particulate filter ash content on the particulate filter back pressure.

[0097] Analysis of the effect of ash content in the particulate filter on the prohibition of oil shut-off: Since the accumulated ash in the particulate filter has a great influence on the prohibition of oil shut-off during carbon load regeneration at different temperatures, it is necessary to understand the effect of ash content on the prohibition of oil shut-off during carbon load regeneration in the particulate filter. The experimental results are as follows: Figure 2 As shown in the figure, under different temperature conditions, after the particulate filter accumulates ash, the carbon load decreases when oil cut-off regeneration is prohibited.

[0098] Analysis of the effect of the ash content in the particulate filter on the back pressure of the particulate filter: As the ash content in the particulate filter accumulates, it will affect the pressure difference of the particulate filter. When the carbon load is 0g, under the condition of the commonly used exhaust flow rate of 250kg / h, the back pressure of the particulate filter is as follows:

[0099] △Particle collector (ash＝87g) -△Particle collector (ash＝0g) =5.95Kpa;

[0100] △Particle collector (ash＝87g) -△Particle collector (ash＝45g) =4.95Kpa;

[0101] △Particle collector (ash＝45g) -△Particle collector (ash＝0g) =1.00Kpa.

[0102] As the ash accumulates in the particulate filter, the pressure difference of the particulate filter will be affected. When the carbon load is 7g and the common exhaust flow rate is 250kg / h, the back pressure of the particulate filter is as follows:

[0103] △Particle collector (ash＝87g) -△Particle collector (ash＝0g) =10.8Kpa;

[0104] △Particle collector (ash＝87g) -△Particle collector (ash＝45g) =6.0Kpa;

[0105] △Particle collector (ash＝87g) -△Particle collector (ash＝45g) =5.44Kpa.

[0106] As the ash accumulates in the particulate filter, the pressure difference of the particulate filter will be affected. When the carbon load is 20g and the common exhaust flow rate is 250kg / h, the back pressure of the particulate filter is as follows:

[0107] △Particle collector(ash＝87g) -△Particle collector (ash＝0g) =5.9Kpa;

[0108] △Particle collector (ash＝87g) -△Particle collector (ash＝45g) =5.7Kpa;

[0109] △Particle collector (ash＝45g) -△Particle collector (ash＝0g) =7.2Kpa.

[0110] Summary: The rapid ash accumulation scheme on the bench is effective, can complete sample production in a short time, can truly reflect the actual impact of ash on particle capture, and at the same time, the ash cost of making particle collectors is low.

[0111] The effects of ash on the particle collector are as follows:

[0112] 5.1 Effect of ash content on prohibition of oil cut-off: Under different temperature conditions, after ash is accumulated in the particulate filter, the carbon load decreases when oil cut-off regeneration is prohibited, and the ash content has less effect on prohibition of oil cut-off.

[0113] 5.2 Effect of ash content on oil cut-off prohibition: Under different carbon loading conditions, the accumulated ash content has a greater impact on the particulate filter pressure. If the particulate filter contains a lot of ash, it will affect the stability of the idle speed, power and other issues. The electronic control system should track the particulate filter ash samples for adaptive calibration.

[0114] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for preparing an ash sample, characterized in that: Includes steps: S1. Determine the target ash value of the particle collector; S2. Accumulate ash content through bench test and make ash samples; S3. Verify the ash samples; Wherein, the step S2 comprises: S201, taking quantitative ash content; S202, drying ash; S203, particle collector benchmark quality confirmation; S204, particle collector soot blowing; S205, the rack accumulated particle collector ash; S206, weigh after accumulation, and record the accumulated mass of ash; S207, repeating steps S204 to S206 for multiple times until the cumulative mass of ash reaches the target ash value of the particle collector, and the ash sample preparation is completed; The step S203 includes: S2031. After weighing the new particulate filter, install the new particulate filter in the exhaust system of the test bench; S2032, the engine is running, heating the particulate filter; S2033, operating the particle collector at the highest temperature point and the maximum flow point for a second set time; S2034, the engine runs according to the set program; S2035, under the first set condition, the particulate trap is regenerated for a third set time; S2036, removing the particle collector, and then weighing the particle collector; S2037, installing the particulate trap in the exhaust system again, and regenerating the particulate trap for a fourth set time under the second set condition; S2038, removing the particulate collector, and then weighing the particulate collector again; S2039. Calculate the reference mass of the particle collector; In step S2036, the particulate trap is removed from the engine exhaust system, and then the removed particulate trap is weighed, and the particulate trap needs to be weighed three times at different temperatures; when the temperature of the particulate trap is 350° C., the particulate trap is weighed for the first time; when the temperature of the particulate trap is 300° C., the particulate trap is weighed for the second time; when the temperature of the particulate trap is 280° C., the particulate trap is weighed for the third time; finally, the average of the three weighing results is calculated as the first mass value; In the above step S2034, the engine speed is first set to 1500 rpm, and the engine runs at 80% load for 10 minutes, and then the engine speed is increased to 4500 rpm, and the engine runs at 80% load for another 10 minutes; In step S2035, the first set condition includes the air-fuel ratio and the exhaust temperature, and the air-fuel ratio is 1.1; In step S2037, the second set condition includes the air-fuel ratio and the exhaust temperature, and the air-fuel ratio is 1.1; The second setting time is 30 minutes, the third setting time is 2 hours, and the fourth setting time is 2 hours.

2. The ash sample preparation method according to claim 1, characterized in that: In the step S202, the ash is placed in a drying furnace, dried at a set temperature for a first set time, and then taken out. The set temperature is 350° C. and the first set time is 20 minutes.

3. The ash sample preparation method according to claim 2, characterized in that: The drying furnace is a muffle furnace, and the set temperature is 350°C.

4. The ash sample preparation method according to any one of claims 1 to 3, characterized in that: In the step S201, a certain amount of ash is weighed using a weighing device at room temperature, and the weighed ash is 100 g.

5. The method for preparing an ash sample according to any one of claims 1 to 3, characterized in that: In step S2032, the engine is started, the engine speed is set to 2500 rpm, the engine runs at 40-50% load, and is heated for a period of time, and then the engine runs at 70% load to heat the particulate filter.

6. The ash sample preparation method according to any one of claims 1 to 3, characterized in that: In the step S206, the particle collector is placed in a drying furnace, and after being kept warm, the particle collector is taken out and weighed, and the accumulated mass of ash is recorded.

7. The method for preparing an ash sample according to any one of claims 1 to 3, characterized in that: The step S205 includes: S2051. Install a particulate collector in the exhaust system of the test bench, and blow a set mass of ash into the particulate collector; S2052, the engine is operated under the dust accumulation condition; S2053. The engine is operated under carbon removal conditions.

8. The method for preparing ash samples according to claim 7, characterized in that: In the step S2052, under the ash accumulation condition, the engine speed is 5000 rpm, and the engine runs at 100% load for 1 hour; in the step S2053, under the carbon removal condition, the engine speed is 3500 rpm, the engine torque is 150 Nm, the air-fuel ratio is 1.1, and the engine runs for 0.5 hours.

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