CN100371569C - A control method for fuel regeneration temperature of diesel engine particulate metal bag filter body - Google Patents

Abstract

The invention relates to a method for controlling the fuel regeneration temperature of a diesel engine particle metal bag filter body, which belongs to a control method for aftertreatment of diesel engine exhaust particles. When the cumulative running time signal (16) of the diesel engine detected by the electronic control unit (17) reaches the calibration value, the fuel burner (13) and the air pump (14) are started to regenerate the metal bag filter (8). During regeneration, the bypass valve (2) and the regeneration exhaust pipe stop valve (6) are opened, and the flow valve (4) and the exhaust tail pipe stop valve (10) are closed. The electronic control unit (17) adjusts and controls the amount of fuel oil burned by the fuel burner (13) and the amount of air added by the air pump (14) according to the signal of the regenerative exhaust thermocouple (21) and the signal of the regenerative gas thermocouple (22). The regeneration exhaust temperature is controlled within 800°C. The invention can effectively control the regeneration temperature of the metal bag type filter body (8), so that the regeneration of the filter body is safe and reliable.

Description

A control method for fuel regeneration temperature of diesel engine particulate metal bag filter body

technical field

The invention belongs to the post-treatment technology of diesel engine exhaust, in particular to a method for controlling the fuel regeneration temperature of a metal bag filter body of diesel engine particles.

Background technique

In order to meet the increasingly stringent emission regulations, a lot of research work has been done on diesel engine exhaust particulate purification technology at home and abroad in the past ten years, and many achievements have been made. The research content mainly includes the internal purification technology and the external post-processing technology. Off-board post-treatment technology can effectively reduce diesel particulate emissions, and has become one of the important measures to control diesel particulate emissions.

At present, the post-treatment technology of diesel particulate emissions mainly includes two aspects, namely the filtration of particulates and the regeneration of filter bodies. From the perspective of particle filtration, the most important filter body currently used is the wall-flow ceramic filter body; in recent years, due to the good characteristics of the metal filter body, the metal filter body has also been gradually applied. When implementing diesel particulate filtration and purification, the filter body needs to be regenerated regularly. At present, a variety of thermal regeneration technologies have been researched at home and abroad, such as electric heating regeneration technology, fuel injection combustion-supporting regeneration technology, gas regeneration technology and so on.

Thermal regeneration technology is the key technology of particle traps. The main problem hindering the practical application of thermal regeneration technology is the reliability of the filter regeneration process. If the amount of particle deposition in the filter body is too much, the combustion of particles during regeneration may melt or burn the filter body, making the filter system invalid; and if the amount of particle deposition in the filter body is too small, on the one hand, it may be difficult to burn particles during regeneration. On the other hand, it also shortens the time interval between two regenerations, causing unnecessary energy consumption and unnecessary impact on the work of the diesel engine.

In order to enable the filter body to be regenerated reliably, the method of accurately controlling the particle deposition amount of the filter body is generally adopted at home and abroad at present. By monitoring the particle deposition amount of the filter body, the particle deposition amount of the filter body during regeneration is kept within a certain range, so as to This avoids possible damage to the filter body during regeneration and ensures the smooth progress of the regeneration process.

However, the regeneration temperature of the filter body is related to many factors. In addition to the amount of particulate deposition that will affect the regeneration temperature of the filter body, the regeneration conditions will also have an important impact on the thermal regeneration of the filter body. In the past, the thermal regeneration technology of the filter body lacked effective control of the regeneration process, and it was difficult to ensure the fast, efficient, safe and reliable regeneration of the filter body.

Contents of the invention

The technical problem to be solved in the present invention:

In order to solve the problem of safety and reliability during thermal regeneration of the metal filter body with relatively poor high temperature resistance, this invention proposes a control method for the fuel regeneration temperature of the metal bag filter body of diesel engine particles according to the structural characteristics of the metal bag filter body . The method can effectively guarantee the reliability of the metal bag filter body of the diesel engine particle when the fuel regeneration technology is adopted.

Technical scheme of the present invention:

The technical solution adopted by the present invention to solve the technical problem: During the operation of the diesel engine, the electronic control unit determines the regeneration time of the metal bag filter according to the length of the operation time of the diesel engine. When the cumulative running time signal of the diesel engine detected by the electronic control unit reaches the calibration value, the electronic control unit opens the bypass valve on the exhaust branch pipe and the regenerative exhaust pipe shut-off valve on the regenerative exhaust pipe through the valve control signal, and closes the exhaust valve. The flow valve on the air pipe and the exhaust tailpipe cut-off valve on the exhaust tailpipe simultaneously start the filter body regeneration through the burner control signal and the air pump control signal to regenerate the metal bag filter body . During regeneration, the exhaust gas of the diesel engine flows out through the exhaust branch pipe; the regeneration gas passes through the regeneration airflow channel between the metal bag filter bodies in the filter to heat the particles deposited in the metal bag filter body to promote their oxidative combustion, and finally the regeneration gas is exhausted Tube out.

During the regeneration process, the electronic control unit adjusts the amount of regeneration gas and external air by controlling the fuel burner and the air pump. When the regenerative gas temperature detected by the electric control unit through the regenerative gas thermocouple exceeds 730°C, the electric control unit controls the oil burner to reduce the fuel supply through the burner control signal; when the regenerative gas temperature is lower than 680°C, the electric control unit passes the combustion The burner control signal controls the oil burner to increase the oil supply, thereby controlling the temperature of the regeneration gas used for the regeneration of the metal bag filter to be between 680-730°C. When the regeneration gas temperature is kept between 680-730°C, the electronic control unit detects the regeneration exhaust gas temperature according to the regeneration exhaust thermocouple signal; when the regeneration exhaust gas temperature is higher than 800°C, the electronic control unit controls The air pump increases the air volume; when the regeneration exhaust temperature is lower than 800°C, no operation is required. By controlling the regeneration temperature, it is ensured that the regeneration exhaust temperature of the metal bag filter body is controlled within a safe range of 800°C.

During the regeneration process, the regeneration gas used for the regeneration of the metal bag filter flows through the outer surface of the metal bag filter, and the flow resistance of the regeneration gas will not change due to the oxidation of the particles, thus ensuring The velocity of regeneration gas is constant. Because the metal bag filter has good thermal conductivity, the high-temperature gas flowing through the outer surface of the metal bag filter can heat the particles deposited on the inner surface of the metal bag filter through the wall of the metal bag filter, and promote the oxidation and combustion of the particles. At the same time, the heat of particle combustion is taken away; the regeneration exhaust is discharged from the regeneration exhaust pipe.

Beneficial effects of the present invention:

The beneficial effect of the invention is that the effective control of the regeneration temperature of the diesel engine particle metal bag filter body during fuel regeneration is realized, and the safe and reliable regeneration of the diesel engine particle metal bag filter body is realized. The research results show that the use of this control method can effectively ensure that the regeneration exhaust temperature of the metal bag filter body is controlled within the range of 800 ° C when the fuel regeneration technology is used, and the diesel engine particle metal bag filter body is in the regeneration process. The reliability has been effectively guaranteed.

Description of drawings

Figure 1 is a schematic diagram of a fuel regeneration temperature control system for diesel engine particulate metal bag filters.

Fig. 2 is the I-I sectional view of Fig. 1.

Fig. 3 is a cross-sectional view of II-II in Fig. 1 .

Fig. 4 is a flow chart of a fuel regeneration temperature control method for a metal bag filter body of diesel engine particulates.

In the figure: 1. Diesel engine, 2. Bypass valve, 3. Exhaust branch pipe, 4. Flow valve, 5. Regeneration exhaust pipe, 6. Regeneration exhaust pipe stop valve, 7. Regeneration exhaust thermocouple, 8. Metal bag filter, 9. Exhaust tail pipe, 10. Exhaust tail pipe stop valve, 11. Regeneration gas thermocouple, 12. Regeneration air flow pipe, 13. Oil burner, 14. Air pump, 15. Exhaust Tube, 16. Cumulative running time signal, 17. Electronic control unit, 18. Burner control signal, 19. Air pump control signal, 20. Valve control signal, 21. Regeneration exhaust thermocouple signal, 22. Regeneration gas thermocouple Signal, 23. Diesel exhaust gas flow, 24. Regeneration gas flow channel, 25. Filter channel, 26. Filter housing, 27. Regeneration gas flow.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

The fuel regeneration temperature control system of diesel particulate metal bag filter is shown in Fig. 1. The control system includes bypass valve 2, exhaust branch pipe 3, flow valve 4, regeneration exhaust pipe 5, regeneration exhaust pipe stop valve 6, regeneration exhaust thermocouple 7, metal bag filter body 8, exhaust tail pipe 9 , Exhaust tailpipe cut-off valve 10, regenerative gas thermocouple 11, regenerative airflow pipe 12, fuel burner 13, air pump 14, exhaust pipe 15, cumulative running time signal 16, electronic control unit 17, burner control signal 18 , air pump control signal 19, valve control signal 20, regenerative exhaust thermocouple signal 21, regenerative gas thermocouple signal 22, regenerative air flow channel 24, filter channel 25 and filter housing 26.

A plurality of metal bag filter bodies 8 arranged together are housed in the filter housing 26 . The front end plate in the filter housing 26 is evenly distributed with holes equal in size and number to the opening size and number of the metal bag filter body 8, and the metal bag filter bodies 8 arranged together are installed on the corresponding front end plate on the hole. Regeneration air flow passages 24 are formed between each metal bag filter body 8 . The front end and the rear end of the filter housing 26 are equipped with an exhaust pipe 15 and an exhaust tail pipe 9 respectively, and the two ends perpendicular to the front and rear ends of the filter housing 26 are respectively equipped with a regeneration air flow pipe 12 and a regeneration exhaust pipe 5 .

On the exhaust pipe 15, an exhaust branch pipe 3 bypassing the atmosphere is drawn. A flow valve 4 is installed on the exhaust pipe 15 between the exhaust branch pipe 3 and the filter housing 26 , and a bypass valve 2 is installed on the exhaust branch pipe 3 . When the metal bag filter 8 is in operation, the circulation valve 4 is opened and the bypass valve 2 is closed, and the exhaust gas of the diesel engine passes through the metal bag filter 8 and is discharged from the exhaust tailpipe 9; when the metal bag filter 8 is regenerated, the flow valve 4 is closed, the bypass valve 2 is opened, and the exhaust gas of the diesel engine is discharged from the exhaust branch pipe 3.

Exhaust tailpipe 9 and regenerative exhaust pipe 5 are respectively equipped with exhaust tailpipe stop valve 10 and regenerative exhaust pipe stop valve 6 . When the metal bag filter body 8 is filtering, the exhaust tailpipe stop valve 10 is opened, and the regenerative exhaust pipe stop valve 6 is closed; After the wall surface, it is discharged by exhaust tailpipe 9. When the metal bag filter body 8 is regenerated, the exhaust tailpipe shut-off valve 10 is closed, the regeneration exhaust pipe shut-off valve 6 is opened, and the regeneration airflow 27 is discharged through the regeneration airflow pipe 12, the regeneration airflow channel 24, and finally by the regeneration exhaust pipe 5.

The fuel burner 13 and the air pump 14 selected according to the displacement of the diesel engine 1 are respectively installed on the port of the regeneration airflow pipe 12 and on the pipe wall of the nearby regeneration airflow pipe 12, near the regeneration airflow pipe of the metal bag filter body 8 A regeneration gas thermocouple 11 for detecting the temperature of the regeneration gas is installed on the 12; a regeneration exhaust thermocouple 7 for detecting the temperature of the regeneration exhaust gas is installed on the regeneration exhaust pipe 5 near the stop valve 6 of the regeneration exhaust pipe.

The electronic control unit 17 is used to detect the cumulative running time signal 16, the regenerative exhaust thermocouple signal 21 and the regenerative gas thermocouple signal 22, analyze and judge the detected signals, and pass the valve control signal 20, the burner control signal 18 and The air pump control signal 19 controls each valve, the fuel burner 13 and the air pump 14 .

The calibration value of the accumulated running time signal 16 of the diesel engine 1 is determined according to the type and operating condition of the diesel engine. The electronic control unit 17 determines the regeneration time of the metal bag filter 8 according to the calibration value of the cumulative running time signal 16 of the diesel engine 1, and according to the detected regeneration gas thermocouple signal 22 and the regeneration exhaust thermocouple signal 21, through the burner The control signal 18 and the air pump control signal 19 control the amount of fuel oil that participates in combustion in the fuel burner 13 and the amount of additional air added by the air pump 14, so as to control the regeneration exhaust temperature of the metal bag filter body 8 to ensure The regenerated exhaust gas temperature of the metal bag filter body 8 is controlled within a safe range within 800°C.

The arrangement of the metal bag filter body 8 inside the filter housing 26 is shown in FIGS. 2 and 3 . The metal bag filter body 8 is bag-shaped, and a plurality of metal bag filter bodies 8 are arranged and installed on the hole of the front end plate in the filter housing 26 having the same opening size as the metal bag filter body 8 . There is a certain gas flow space between each metal bag filter body 8 , which constitutes a regeneration airflow channel 24 . When the metal bag filter 8 is working, the exhaust gas of the diesel engine enters the metal bag filter 8 through the exhaust pipe 15, and then flows out through the wall of the metal bag filter 8; Filtered by the wall surface, deposited on the inner surface of the metal bag filter body 8. When the metal bag filter 8 is regenerated, the circulation valve 4 is closed, the bypass valve 2 is opened, and the exhaust gas of the diesel engine is discharged through the exhaust branch pipe 3; The regeneration gas flow channel 24 formed between the outer surface and the filter housing 26 flows through. Since the regeneration airflow 27 flows through the outer surface of the metal bag filter body 8, the flow resistance will not change due to the oxidation of the particles during the regeneration process, thereby ensuring a constant speed of the regeneration gas during the entire regeneration process. Because the metal bag filter body 8 has good thermal conductivity, the high-temperature gas flowing through the outer surface of the metal bag filter body 8 can heat the particles deposited on the inner surface of the metal bag filter body 8 to promote The particles are oxidized and burned, and at the same time, the heat of particle combustion is taken away. The regeneration gas flow 27 is finally discharged from the regeneration exhaust pipe 5 .

The flow chart of the fuel regeneration temperature control method for diesel particulate metal bag filter body is shown in Fig. 4 .

In order to meet the practicability and reliability requirements of the system, this control method adopts the scheme of determining the regeneration time according to the running time of the diesel engine. When the accumulated running time signal 16 of the diesel engine detected by the electronic control unit 17 reaches the calibrated set value, the fuel burner 13 and the air pump 14 are started to regenerate the metal bag filter 8 . The electronic control unit 17 closes the flow valve 4 and the exhaust tail pipe stop valve 10 through the valve control signal 20 , and simultaneously opens the bypass valve 2 and the regenerative exhaust pipe stop valve 6 . When the metal bag filter body 8 is regenerated, the exhaust gas of the diesel engine is discharged through the exhaust branch pipe 3; The formed regenerative air flow channel 24 flows through, and finally is discharged through the regenerative exhaust pipe 5 .

During the regeneration process of the metal bag filter body 8, the electric control unit 17 uses the regeneration gas thermocouple 11 and the regeneration exhaust thermocouple 7 according to the regeneration gas thermocouple signal 22 and the regeneration exhaust thermocouple signal 21 for the metal bag filter. The temperature of the gas regenerated by the filter body 8 and the temperature of the regenerated exhaust gas flowing through the metal bag filter body 8 are monitored.

When the gas temperature exceeds 730°C, the electric control unit 17 controls the oil burner 13 to reduce the oil supply through the burner control signal 18; when the gas temperature is lower than 680°C, the electric control unit 17 controls the oil burner 13 through the burner control signal 18 Increase the oil supply; thereby control the temperature of the regeneration gas used for the regeneration of the metal bag filter body 8 between 680-730°C.

When the temperature of the regenerative gas regenerated by the metal bag filter 8 is kept between 680-730°C, the electric control unit 17 controls the regeneration gas flowing through the metal bag filter 8 through the regenerative exhaust thermocouple 7 according to the signal 21 of the regenerative exhaust thermocouple. Exhaust temperature is checked. When the regeneration exhaust temperature is higher than 800° C., the electronic control unit 17 controls the air pump 14 to increase the air volume through the air pump control signal 19 . The increase of the air volume by the air pump 14 will inevitably lead to a decrease in the temperature of the regeneration gas, so the temperature of the regeneration gas needs to be further detected by the regeneration gas thermocouple 11 to determine whether to increase the fuel supply of the oil burner 13 . When the regeneration exhaust temperature is lower than 800°C, no operation is required.

After the electronic control unit 17 controls the regeneration time to continue for 10 minutes, the fuel burner 13 and the air pump 14 are closed through the control of the electronic control unit 17, and the flow valve 4 and the exhaust tailpipe stop valve 10 are opened at the same time, and the bypass valve 2 and the Regeneration exhaust pipe stop valve 6, the regeneration process of metal bag type filter body 8 ends.

Since the diesel engine exhaust is completely bypassed by the exhaust branch pipe 3 during the regeneration of the metal bag filter body 8, and the regeneration air flow 27 used for the regeneration of the metal bag filter body 8 flows through the outer surface of the metal bag filter body 8 , so the flow resistance of the regeneration gas will not change due to the oxidation of particles during the regeneration process, thus ensuring that the speed of the regeneration gas is constant throughout the regeneration process, and the regeneration process of the metal bag filter body 8 is free from external and particle oxidation Burning effects. After the adjustment of the fuel burner 13 and the air pump 14 is completed, it is no longer necessary to adjust the fuel burner 13 and the air pump 14 when the metal bag filter 8 is regenerated, and the requirements for the control system are relatively low.

Claims (1)

1. the controlling method of a diesel particulation metal bag type filtering-body fuel regeneration temperature, it is characterized in that, when ECU (Electrical Control Unit) (17) detects the accumulated running time signal (16) of diesel engine (1) when reaching calibration value, open regeneration outlet pipe stop valve (6) on the bypass valve (2) on the exhaust branch pipe (3) and the outlet pipe (5) of regenerating by valve control signal (20), close flowing valve (4) on the outlet pipe (15) and the tailpipe stop valve (10) on the tailpipe (9); Simultaneously, start filter regeneration fuel oil burner (13), start air pump (14), metal bag type filtering-body (8) is regenerated by air pump control signal (19) by burner control signal (18); In regenerative process, ECU (Electrical Control Unit) (17) is regulated the regenerative combustion gas amount by control oil burner (13), regulates adding air quantity by control air pump (14);

When surpassing 730 ℃ by the detected regenerative combustion gas temperature of regenerative combustion gas thermocouple (11), ECU (Electrical Control Unit) (17) reduces fuel delivery by burner control signal (18) control oil burner (13); When the regenerative combustion gas temperature was lower than 680 ℃, ECU (Electrical Control Unit) (17) increased fuel delivery by burner control signal (18) control oil burner (13), and control is used for the regenerative combustion gas temperature of metal bag type filtering-body (8) regeneration between 680-730 ℃;

When the regenerative combustion gas temperature remained between 680-730 ℃, ECU (Electrical Control Unit) (17) detected the regeneration delivery temperature according to regeneration well as exhaust thermocouples signal (21); When the regeneration delivery temperature was higher than 800 ℃, ECU (Electrical Control Unit) (17) increased air quantity by air pump control signal (19) control air pump (14); By control, make the regeneration delivery temperature be controlled at 800 ℃ with in the interior safety range to the regeneration delivery temperature.

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