Carbon cleaning device and carbon cleaning method for DPF with high carbon load

Abstract

The present invention relates to the technical field of DPF carbon removal, and discloses a carbon removal device for DPF with high carbon load, comprising a diesel oxidation catalyst, a diesel particulate trap, a mixer, a selective catalytic reduction catalyst and an ammonia escape trap connected in sequence, the inlet of the diesel oxidation catalyst is also provided with an out-of-cylinder hydrocarbon nozzle, and also includes a thermal management control device, the inlet of the diesel particulate trap is provided with a first temperature sensor connected to the thermal management control device, the thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor, so that the inlet temperature of the diesel particulate trap is 380 to 430 degrees Celsius, and the outlet and inlet of the diesel particulate trap are connected with a pressure difference sensor. The present invention also discloses a carbon removal method for a carbon removal device for DPF with high carbon load. The carbon removal device for DPF with high carbon load and the carbon removal method thereof of the present invention greatly reduce the probability of rework when the DPF is seriously blocked, and effectively reduce the time cost and later maintenance cost of the terminal customers.

Description

Technical Field

[0001] The invention relates to the technical field of DPF carbon removal, and in particular to a carbon removal device and a carbon removal method for a DPF with high carbon load. Background Art

[0002] The particulate emissions of diesel engines are collected by DPF. When the carbon load in the DPF is not particularly high (first level), the carbon load can be controlled through (driving) passive regeneration and (driving) active regeneration; when the carbon load in the DPF reaches the second level, the industry currently adopts the parking (active) regeneration method to burn the carbon load in the DPF; when the carbon load in the DPF reaches the third level, the corresponding strategy in the industry is: triggering the DPF severe blockage fault code, disabling parking regeneration, limiting the speed and torque of the vehicle (the engine cannot work normally), and requiring the DPF to be repaired. This repair and carbon cleaning method uses special equipment to clean the DPF. The DPF is immersed in liquid, uses ultrasonic vibration to clean carbon deposits, and then dries the DPF.

[0003] However, if the application condition is prone to high smoke, and the driver makes improper operations due to the rush to meet the deadline (failed to do parking regeneration in time or pressed the regeneration prohibition switch by mistake) or the driver did not notice that the carbon load in the DPF has reached the second level (needing parking regeneration), then the engine continues to work under this application condition, which can easily cause the DPF carbon load to reach the third level. At this time, the speed and torque limit of the engine (cannot work normally) is likely to cause customer complaints, and the repair will also delay a lot of customer time.

[0004] In addition, the existing technical system is not friendly to certain typical applications and driver misoperation, and increases maintenance costs and time costs. For example, loaders, buses, etc. are prone to frequent full-throttle starting or long-term low-speed and low-torque driving conditions. In this case, when the carbon load in the DPF reaches the second level, the driver may not be able to accurately feel the engine torque limit. If the driver does not check the instrument's fault prompt in time or the driver mistakenly presses the regeneration prohibition switch, or fails to perform parking regeneration in time, the DPF carbon load is likely to reach the third level. At this time, the driver will clearly feel the speed limit (the machine can no longer work normally), and the DPF can only be repaired.

[0005] It takes 2 to 6 days to send the DPF for repair and return, and the cleaning process also takes time. Especially for the field of engineering machinery, this time cost far exceeds the value of the DPF itself, which customers are extremely reluctant to bear.

[0006] In this case, the serious blockage of DPF is not caused by ash blockage but by the accumulation of carbon load. If the carbon load can be quickly and safely reduced to the fault-eliminated state through self-service maintenance by the driver, the robustness of the system for customer groups and special working conditions can be increased, reducing customer complaints and improving product competitiveness. However, the existing technology does not provide a method for self-service maintenance to reduce the carbon load of DPF. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the above-mentioned technology and provide a carbon cleaning device and a carbon cleaning method for DPF with high carbon load, which greatly reduces the probability of rework when the DPF is severely blocked, effectively reduces the time cost and subsequent maintenance cost of end customers, improves the customer experience through self-service maintenance, and also improves the robustness of the engine control system to customer groups and special working conditions.

[0008] To achieve the above-mentioned purpose, the carbon removal device for DPF with high carbon load designed by the present invention comprises a diesel oxidation catalyst, a diesel particulate trap, a mixer, a selective catalytic reduction catalyst and an ammonia escape trap connected in sequence, the inlet of the diesel oxidation catalyst is also provided with an off-cylinder hydrocarbon nozzle, and also comprises a thermal management control device, the inlet of the diesel particulate trap is provided with a first temperature sensor connected to the thermal management control device, the thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor, so that the inlet temperature of the diesel particulate trap is 380 to 430 degrees Celsius, and the outlet and inlet of the diesel particulate trap are connected with a pressure difference sensor.

[0009] Preferably, a second temperature sensor is provided at the inlet of the diesel oxidation catalyst, a third temperature sensor is provided at the outlet of the diesel particulate filter, and a fourth temperature sensor is provided at the outlet of the ammonia escape filter. The second temperature sensor, the third temperature sensor and the fourth second temperature sensor are all connected to the thermal management control device.

[0010] Preferably, a urea nozzle is provided at the inlet of the mixer, and a post-NOx sensor is provided at the outlet of the ammonia slip trap.

[0011] A carbon cleaning method for a DPF high carbon loading carbon cleaning device comprises the following steps:

[0012] A) estimating the carbon load of the diesel particulate filter based on the pressure difference sensor, if it is greater than a first threshold, in the parking condition, starting passive regeneration, at this time, the hydrocarbon nozzle outside the cylinder does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter is controlled by the thermal management control device to be 380-430 degrees Celsius, and the regeneration time is T1;

[0013] B) after the regeneration is completed, the carbon load of the current diesel particulate filter is estimated based on the pressure difference sensor. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0014] C) starting active regeneration, the hydrocarbon nozzle outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter is controlled to be 500-600 degrees Celsius by the thermal management control device, and the regeneration time is T2;

[0015] D) After the regeneration is completed, the carbon load of the current diesel particulate filter is estimated based on the pressure difference sensor. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed, otherwise, the active regeneration is entered again, and the regeneration time is T2. If it is still higher than the third threshold value after repeating N2 times, an error is reported;

[0016] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0017] Preferably, during passive regeneration and active regeneration, control of system NOX emissions is achieved through a urea nozzle, a mixer, a selective catalytic reduction catalyst, an ammonia escape trap, a rear NOX sensor, a third temperature sensor at the outlet of the diesel particulate filter, and a fourth temperature sensor at the outlet of the ammonia escape trap.

[0018] Preferably, a second temperature sensor provided at the inlet of the diesel oxidation catalyst, a first temperature sensor provided at the inlet of the diesel particulate filter, a third temperature sensor provided at the outlet of the diesel particulate filter and a fourth temperature sensor provided at the outlet of the ammonia slip filter are connected to the thermal management control device to monitor the temperature at each position.

[0019] Preferably, a second temperature sensor disposed at the inlet of the diesel oxidation catalyst is used to determine whether the temperature of the diesel oxidation catalyst has reached the start-up temperature of hydrocarbon injection, and is also used to determine whether the original exhaust temperature is adjusted in place during passive regeneration in the parking state.

[0020] Preferably, a first temperature sensor disposed at the inlet of the diesel particulate filter is used to determine whether the target temperature of active regeneration has been reached, and also monitor whether the regeneration temperature exceeds a limit.

[0021] Preferably, a urea nozzle is provided at the inlet of the mixer, and a third temperature sensor provided at the outlet of the diesel particulate filter is used to judge whether the combustion temperature of the diesel particulate filter exceeds the limit, and also to judge whether the urea injection reaches the start-up temperature.

[0022] Preferably, a urea nozzle is provided at the inlet of the mixer, and a post-NOX sensor is provided at the outlet of the ammonia escape trap. The urea nozzle sprays urea spray in front of the mixer when the spraying temperature is reached. The urea spray is pyrolyzed and hydrolyzed to generate NH3 which is mixed with the exhaust gas at the mixer. Then, in the selective catalytic reduction catalyst, NH3 reacts with NOX, and excess NH3 escapes to the ammonia escape trap and is oxidized. The post-NOX sensor is used to monitor whether the NOX in the system emissions has met the emission regulations.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. Greatly reduce the probability of DPF repair when it is seriously blocked, effectively reducing the time cost and subsequent maintenance cost of end customers;

[0025] 2. The self-service maintenance method improves the customer experience and also improves the robustness of the engine control system for different customer groups and special working conditions;

[0026] 3. Under the premise of ensuring safety, the serious blockage of DPF can be eliminated at a very fast speed (about 1hr-1.5hr). Compared with the existing technology of repair and resulting in 2-7 days of downtime, it has obvious advantages and can improve product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of the carbon removal device for DPF with high carbon load according to the present invention.

[0028] The components in the figure are numbered as follows:

[0029] Diesel oxidation catalyst 1, diesel particulate filter 2, mixer 3, selective catalytic reduction catalyst 4, ammonia escape filter 5, external hydrocarbon nozzle 6, differential pressure sensor 7, urea nozzle 8, post-NOX sensor 9, first temperature sensor 11, second temperature sensor 12, third temperature sensor 13, fourth temperature sensor 14. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0031] First, the "passive regeneration + active regeneration" that needs to be used in the parking state is explained:

[0032] The hydrocarbon nozzle outside the cylinder sprays hydrocarbon at the inlet of the diesel oxidation catalyst. The hydrocarbon oxidizes with the oxygen in the exhaust gas inside the diesel oxidation catalyst to release heat, raising the temperature of the diesel particulate filter inlet to 500-600 degrees Celsius. The carbon load collected by the diesel particulate filter is burned with the oxygen in the exhaust gas at 500-600 degrees Celsius, which is active regeneration. If the active regeneration occurs when the vehicle is parked, this active regeneration is also called parking regeneration.

[0033] In parking conditions, through the thermal management control device (EGR is closed, the combustion mode is the same as active regeneration, the intake throttle valve and the exhaust back pressure valve are controlled according to the exhaust temperature increase demand), the hydrocarbon injection of the external hydrocarbon nozzle is stopped, and the temperature range of the diesel particulate filter is mainly 380 ~ 430 degrees Celsius. This situation is defined as passive regeneration in this patent.

[0034] In addition, if the hydrocarbon nozzle outside the cylinder stops injecting hydrocarbons into the inlet of the diesel oxidation catalyst and adopts the normal combustion mode, the temperature inside the diesel particulate filter (mainly depends on the original exhaust temperature) is lower than that in the active regeneration situation. At this time, the carbon load in the diesel particulate filter and the NO2 entering the diesel particulate filter undergo a slow oxidation reaction. This regeneration method is called general passive regeneration. The temperature range of the diesel particulate filter under normal driving conditions and normal combustion mode (no diesel particulate filter thermal management) is mainly between 200 and 350 degrees Celsius.

[0035] The ability of the above three regeneration methods to reduce carbon load is from weak to strong: general passive regeneration, passive regeneration, and active regeneration. The temperature of the diesel particulate filter under the three regeneration methods is from low to high: general passive regeneration, passive regeneration, and active regeneration. Therefore, the carbon reduction ability of passive regeneration (parking situation) is much stronger than that of general passive regeneration, and the temperature control of the diesel particulate filter is safer than that of active regeneration.

[0036] Example 1

[0037] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0038] When this embodiment is used, the following steps are included:

[0039] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold value, which is 62.4 grams in this embodiment, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 390 degrees Celsius by the thermal management control device. The regeneration time is T1, which is 30 minutes;

[0040] B) After the regeneration is completed, the current carbon load of the diesel particulate trap 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, which is 58.5 grams in this embodiment, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0041] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 540 degrees Celsius by the thermal management control device, and the regeneration time is T2, which is 30 minutes in this embodiment;

[0042] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, which is 35.1 grams in this embodiment, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0043] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0044] Example 2

[0045] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0046] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0047] When this embodiment is used, the following steps are included:

[0048] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to 420 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0049] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0050] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 570 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0051] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0052] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0053] Among them, during the passive regeneration and active regeneration process, the control of system NOX emissions is achieved through the urea nozzle 8, the mixer 3, the selective catalytic reduction catalyst 4, the ammonia escape trap 5, the rear NOX sensor 9, the third temperature sensor 13 arranged at the outlet of the diesel particulate trap 2 and the fourth temperature sensor 14 arranged at the outlet of the ammonia escape trap 5.

[0054] Example 3

[0055] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0056] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0057] When this embodiment is used, the following steps are included:

[0058] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to 410 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0059] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0060] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 560 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0061] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0062] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0063] Among them, a second temperature sensor 12 arranged at the inlet of the diesel oxidation catalyst 1, a first temperature sensor 11 arranged at the inlet of the diesel particulate filter 2, a third temperature sensor 13 arranged at the outlet of the diesel particulate filter 2 and a fourth temperature sensor 14 arranged at the outlet of the ammonia escape trap 5 are connected to the thermal management control device to monitor the temperature of each position.

[0064] Example 4

[0065] like Figure 1As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0066] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0067] When this embodiment is used, the following steps are included:

[0068] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to 400 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0069] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0070] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 520 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0071] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0072] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0073] The second temperature sensor 12 disposed at the inlet of the diesel oxidation catalyst 1 is used to determine whether the temperature of the diesel oxidation catalyst 1 reaches the starting temperature of hydrocarbon injection, and is also used to determine whether the original exhaust temperature is adjusted in place during passive regeneration in the parking state.

[0074] Example 5

[0075] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0076] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0077] When this embodiment is used, the following steps are included:

[0078] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to 430 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0079] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0080] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 500 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0081] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0082] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0083] The first temperature sensor 11 disposed at the inlet of the diesel particulate filter 2 is used to determine whether the target temperature of the active regeneration has been reached, and also to monitor whether the regeneration temperature exceeds the limit.

[0084] Example 6

[0085] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0086] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0087] In addition, a urea nozzle 8 is provided at the inlet of the mixer 3 , and a post-NOx sensor 9 is provided at the outlet of the ammonia slip trap 5 .

[0088] When this embodiment is used, the following steps are included:

[0089] A) The current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is greater than the first threshold, the passive regeneration is started in the parking condition. At this time, the external hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to 380 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0090] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0091] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 600 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0092] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0093] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0094] The third temperature sensor 13 disposed at the outlet of the diesel particulate trap 2 is used to determine whether the combustion temperature of the diesel particulate trap 2 exceeds the limit, and is also used to determine whether the urea injection reaches the injection start temperature.

[0095] Example 7

[0096] like Figure 1 As shown, a carbon removal device for DPF with high carbon load includes a diesel oxidation catalyst 1, a diesel particulate trap 2, a mixer 3, a selective catalytic reduction catalyst 4 and an ammonia escape trap 5 which are connected in sequence. The inlet of the diesel oxidation catalyst 1 is also provided with an out-of-cylinder hydrocarbon nozzle 6. It also includes a thermal management control device. The inlet of the diesel particulate trap 2 is provided with a first temperature sensor 11 connected to the thermal management control device. The thermal management control device controls the original exhaust temperature according to the data of the first temperature sensor 11, so that the inlet temperature of the diesel particulate trap 2 is 380-430 degrees Celsius. The outlet and inlet of the diesel particulate trap 2 are connected with a pressure difference sensor 7.

[0097] Among them, a second temperature sensor 12 is provided at the inlet of the diesel oxidation catalyst 1, a third temperature sensor 13 is provided at the outlet of the diesel particulate filter 2, and a fourth temperature sensor 14 is provided at the outlet of the ammonia escape trap 5. The second temperature sensor 12, the third temperature sensor 13 and the fourth temperature sensor 14 are all connected to the thermal management control device.

[0098] In addition, a urea nozzle 8 is provided at the inlet of the mixer 3 , and a post-NOx sensor 9 is provided at the outlet of the ammonia slip trap 5 .

[0099] When this embodiment is used, the following steps are included:

[0100] A) The carbon load of the current diesel particulate filter 2 is estimated based on the differential pressure sensor 7. When sampling in this embodiment, the speed reciprocating sweep range is [1300rpm, 2200rpm]. A carbon load calculation sampling point is taken every 100rpm, with a total of 20 sampling points. The carbon load estimation method for each sampling point adopts an algorithm based on the differential pressure sensor, that is, the characteristic that the DPF differential pressure value DeltaP corresponding to different carbon loads under different exhaust gas flow rates is different. This relationship is determined by calibration, and then the carbon loads of the 20 sampling points are averaged to obtain the carbon load obtained by the speed sweep learning. If it is greater than the first threshold, passive regeneration is started under the parking condition. At this time, the out-of-cylinder hydrocarbon nozzle 6 does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 410 degrees Celsius by the thermal management control device, and the regeneration time is T1;

[0101] B) after the regeneration is completed, the current carbon load of the diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the second threshold value, and the second threshold value is less than the first threshold value, the process proceeds to step C), otherwise, the process proceeds to step E);

[0102] C) starting active regeneration, the hydrocarbon nozzle 6 outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter 2 is controlled to be 550 degrees Celsius through the thermal management control device, and the regeneration time is T2;

[0103] D) After the regeneration is completed, the carbon load of the current diesel particulate filter 2 is estimated based on the pressure difference sensor 7. If it is less than the third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, the active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported;

[0104] E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

[0105] Among them, the urea nozzle 8 sprays urea spray in front of the mixer 3 when the spraying temperature is reached. The urea spray is pyrolyzed and hydrolyzed to generate NH3 which is mixed with the exhaust gas at the mixer 3. Then, in the selective catalytic reduction catalyst 4, NH3 reacts with NOX. The excess NH3 escapes to the ammonia escape trap 5 and is oxidized. The rear NOX sensor 9 is used to monitor whether the NOX in the system emission has met the emission regulations.

[0106] In addition, in the above embodiment, when performing passive regeneration, the vehicle must meet the following conditions:

[0107] 1) In neutral;

[0108] 2) Tighten the handbrake;

[0109] 3)Throttle 0;

[0110] 4) The foot brake is not pressed;

[0111] 5) The clutch is not depressed;

[0112] 6) PTO is not enabled;

[0113] 7) The engine is at idle speed [700rpm, 800rpm];

[0114] 8) The water temperature is within the calibration range [75degC, 100degC];

[0115] 9) The remaining fuel volume is calibrated to 20L;

[0116] 10) There are no fault codes that affect active regeneration.

[0117] Similarly, the thermal management control device controls the original exhaust temperature by closing EGR and adjusting the opening of the intake throttle valve and the exhaust back pressure valve.

[0118] In the prior art, it is required to repair (clean the DPF) to eliminate the fault state when the DPF carbon load reaches the third level, but in this application, the driver can use self-service maintenance on site to reduce the DPF carbon load; this application adopts a completely different fault elimination strategy: first use passive regeneration to initially and safely reduce the carbon load when the vehicle is parked, and then use active regeneration to quickly reduce the carbon load, thereby eliminating the DPF serious blockage fault. This solves the problem in the industry that the carbon load cannot be safely and quickly reduced when the DPF is blocked to the third level.

[0119] The key points of this application are:

[0120] 1. In case of severe DPF blockage, the system allows customers to perform self-maintenance and carbon removal within the specified time. If customers still do not perform the maintenance outside the specified time, the system requires customers to return the DPF for repair based on the need to protect the engine;

[0121] 2. The strategy of "passive regeneration + parking regeneration" to reduce the carbon load of DPF in the parking state can eliminate the serious blockage of DPF. The temperature of passive regeneration is safer, which can ensure the safety of DPF under high carbon load. When the carbon load is reduced to a certain threshold, active regeneration is used to quickly reduce the carbon load, which takes into account both safety and speed as a whole.

[0122] 3. In the parking state, the carbon load can be estimated more accurately by scanning the speed back and forth and taking samples to calculate the average value, which can control regeneration more safely.

[0123] 4. In the parking state, if a single passive regeneration does not reduce the carbon load to the calibration threshold, the passive regeneration time will be automatically and reasonably extended to a certain extent, which greatly increases the probability of successful carbon cleaning of the system.

[0124] The carbon cleaning device and carbon cleaning method for DPF with high carbon load of the present invention greatly reduce the probability of rework when DPF is seriously clogged, and effectively reduce the time cost and subsequent maintenance cost of end customers; improve the customer experience through self-service maintenance, and also improve the robustness of the engine control system to customer groups and special working conditions; under the premise of ensuring safety, the serious blockage of DPF can be eliminated at a very fast speed (about 1hr-1.5hr), which is significantly superior to the prior art that causes downtime of 2-7 days due to rework, and can improve product competitiveness.

[0125] In the technical solutions currently used in the market, when the DPF is blocked to a certain extent, a fault code will be reported, and the speed and torque will be limited. Customers are required to return for repair (cleaning) after seeing the fault code and text prompts indicating that the DPF is seriously blocked. The market has replaced the maintenance solution of this patent with the DPF return repair method, and its shortcomings will not be repeated.

[0126] It should be noted that in order to protect this patent, the self-service carbon cleaning strategy involved in the patent is not limited to its form of existence. For example, the strategy can be directly implemented in the engine control system, or it can be temporarily or permanently updated to the engine system through remote upgrades, or the strategy can be updated to the engine control system through service tools.

[0127] In order to protect this patent, only the temperature control strategy or the regeneration carbon load estimation method in the parking regeneration is modified. This local small modification does not fundamentally change the carbon cleaning strategy of "parking passive regeneration + active regeneration" under high carbon load, which is obvious to professionals in the industry.

[0128] In addition, the system device for the application of this strategy is relatively flexible. Whether SCR and EGR exist at the same time, whether the intake throttle valve and exhaust back pressure valve exist at the same time, and whether the nozzle for providing HC to DOC belongs to in-cylinder injection or out-cylinder injection, all of these do not affect the implementation of this patent.

[0129] In addition, in text editing, making changes to certain professional terms without changing the essential content of this patent is a clear infringement in the industry.

[0130] Finally, it should be pointed out that the above content is a further detailed description of the invention in combination with specific implementation methods. It cannot be considered that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, simple replacements made without departing from the concept of the present invention should be regarded as belonging to the protection scope of the present invention. The above embodiments are only more representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments, and there can be many variations. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention should be considered to belong to the protection scope of the present invention.

[0131] At the same time, it should be noted that the description of the above technical solutions is exemplary, and this specification can be embodied in different forms and should not be construed as being limited to the technical solutions set forth herein. On the contrary, providing these descriptions will make the disclosure of the present invention thorough and complete, and will fully convey the scope disclosed in this specification to those skilled in the art. In addition, the technical solutions of the present invention are limited only by the scope of the claims. The features of the various embodiments of the present invention may be partially or completely combined or spliced ​​with each other, and may be performed in various different configurations as those skilled in the art may fully understand. The embodiments of the present invention may be performed independently of each other, or may be performed together in a mutually dependent relationship.

[0132] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and the above structures should be regarded as belonging to the protection scope of the present invention.

Claims

1. A carbon cleaning method for a DPF high carbon loading carbon cleaning device, characterized in that: A carbon removal device for a DPF with a high carbon load comprises a diesel oxidation catalyst (1), a diesel particulate trap (2), a mixer (3), a selective catalytic reduction catalyst (4) and an ammonia escape trap (5) connected in sequence, wherein the inlet of the diesel oxidation catalyst (1) is further provided with an out-of-cylinder hydrocarbon nozzle (6), and further comprises a thermal management control device, wherein the inlet of the diesel particulate trap (2) is provided with a first temperature sensor (11) connected to the thermal management control device, and the thermal management control device controls the original exhaust temperature according to data of the first temperature sensor (11) so that the inlet temperature of the diesel particulate trap (2) is 380-430 degrees Celsius, and the outlet and inlet of the diesel particulate trap (2) are connected with a pressure difference sensor (7). The carbon removal method comprises the following steps: A) estimating the current carbon load of the diesel particulate filter (2) based on the pressure difference sensor (7), and if it is greater than a first threshold, starting passive regeneration under parking conditions, at which time the off-cylinder hydrocarbon nozzle (6) does not spray hydrocarbon, and the inlet temperature of the diesel particulate filter (2) is controlled to be 380-430 degrees Celsius by a thermal management control device, and the regeneration time is T1; B) after the regeneration is completed, the current carbon load of the diesel particulate filter (2) is estimated based on the pressure difference sensor (7), if it is less than the second threshold value, the second threshold value is less than the first threshold value, then the process proceeds to step C), otherwise, the process proceeds to step E); C) starting active regeneration, the hydrocarbon nozzle (6) outside the cylinder sprays hydrocarbon, and the inlet temperature of the diesel particulate filter (2) is controlled to be 500-600 degrees Celsius by the thermal management control device, and the regeneration time is T2; D) After the regeneration is completed, the carbon load of the current diesel particulate filter (2) is estimated based on the pressure difference sensor (7). If it is less than a third threshold value, and the third threshold value is less than the second threshold value, the regeneration is completed. Otherwise, active regeneration is started again, and the regeneration time is T2. If it is still higher than the third threshold value after N2 times, an error is reported; E) Re-enter passive regeneration, the regeneration time is T1, if it is still higher than the second threshold after repeating N1 times, an error is reported.

2. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: The inlet of the diesel oxidation catalyst (1) is provided with a second temperature sensor (12), the outlet of the diesel particulate filter (2) is provided with a third temperature sensor (13), the outlet of the ammonia escape filter (5) is provided with a fourth temperature sensor (14), and the second temperature sensor (12), the third temperature sensor (13) and the fourth temperature sensor (14) are all connected to the thermal management control device.

3. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: The inlet of the mixer (3) is provided with a urea nozzle (8), and the outlet of the ammonia escape trap (5) is provided with a post-NOx sensor (9).

4. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: During the passive regeneration and active regeneration process, the NOX emission from the system is controlled through the urea nozzle (8), the mixer (3), the selective catalytic reduction catalyst (4), the ammonia escape trap (5), the rear NOX sensor (9), the third temperature sensor (13) arranged at the outlet of the diesel particulate trap (2), and the fourth temperature sensor (14) arranged at the outlet of the ammonia escape trap (5).

5. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: The temperature at each position is monitored by connecting to the thermal management control device via a second temperature sensor (12) provided at the inlet of the diesel oxidation catalyst (1), a first temperature sensor (11) provided at the inlet of the diesel particulate trap (2), a third temperature sensor (13) provided at the outlet of the diesel particulate trap (2), and a fourth temperature sensor (14) provided at the outlet of the ammonia slip trap (5).

6. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: A second temperature sensor (12) provided at the inlet of the diesel oxidation catalyst (1) is used to determine whether the temperature of the diesel oxidation catalyst (1) has reached the start-up temperature of hydrocarbon injection, and is also used to determine whether the original exhaust temperature has been adjusted to the correct level during passive regeneration in a parking state.

7. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: A first temperature sensor (11) arranged at the inlet of the diesel particulate filter (2) is used to determine whether the target temperature of active regeneration has been reached, and also to monitor whether the regeneration temperature exceeds a limit.

8. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: A urea nozzle (8) is provided at the inlet of the mixer (3), and a third temperature sensor (13) provided at the outlet of the diesel particulate filter (2) is used to judge whether the combustion temperature of the diesel particulate filter (2) exceeds a limit, and is also used to judge whether the urea injection reaches the injection start temperature.

9. The carbon cleaning method for a DPF high carbon loading carbon cleaning device according to claim 1, characterized in that: The inlet of the mixer (3) is provided with a urea nozzle (8), and the outlet of the ammonia escape trap (5) is provided with a post-NOX sensor (9). When the spraying temperature is reached, the urea nozzle (8) sprays urea spray in front of the mixer (3). The urea spray is pyrolyzed and hydrolyzed to generate NH3, which is mixed with the exhaust gas at the mixer (3). Then, in the selective catalytic reduction catalyst (4), NH3 reacts with NOX, and excess NH3 escapes to the ammonia escape trap (5) and is oxidized. The post-NOX sensor (9) is used to monitor whether the NOX in the system emission has met the emission regulations.

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