A vehicle-mounted DPF regeneration control method and device

Abstract

The present invention discloses a vehicle-mounted DPF regeneration control method and device. When the amount of particulate matter trapped by the DPF reaches a certain limit and the DPF needs to be regenerated, the present invention collects the vehicle-mounted DPF and the surrounding environment information of the exhaust pipe outlet based on radar ranging, heat source imaging, image recognition and judgment technology, and synchronously transmits it to the environment state processing controller. The DPF environment state processing controller receives the final obstacle judgment result of the image recognition and judgment module, and based on the distance l between the obstacle and the particle trap within the DPF regeneration range a , the first distance threshold d1, the second distance threshold d2, judge whether the current environment is suitable for vehicle-mounted DPF regeneration, and issue corresponding instructions; execute the corresponding regeneration judgment logic; the alarm device receives the control instruction of the DPF environment status processing controller and issues corresponding warnings. The vehicle-mounted DPF regeneration control method and device designed by the present invention can avoid the danger of DPF high-temperature exhaust regeneration to surrounding people, animals and flammable and explosive environments, and ensure that the DPF regeneration process is always in a safe environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine exhaust aftertreatment, and in particular relates to a vehicle-mounted DPF regeneration control method and device, which are used to determine whether the current environment is suitable for vehicle-mounted DPF regeneration and issue corresponding instructions. Background Art

[0002] With the implementation of the sixth phase of the national motor vehicle pollutant emission standards, the emission limits for engine exhaust particulate matter PM (Particulate Matter) National VI A and National VI B are 4.5mg / km and 3mg / km. The particulate filter DPF (Diesel Particulate Filter) captures engine exhaust particles and is a major technical measure to reduce particulate emissions. When the amount of particulate matter captured by the DPF reaches a certain limit, the particulate matter in the DPF needs to be burned to achieve DPF regeneration. At present, the main technical means to achieve DPF regeneration is to burn the particulate matter captured by the DPF by injecting fuel into the exhaust pipe to remove the particulate matter deposited in the DPF. This method will generate high-temperature exhaust during the regeneration process. When the amount of particulate matter captured by the DPF reaches the limit, the DPF regeneration behavior will be carried out anytime and anywhere. If there are animals, flammable and explosive materials in the surrounding environment, it will bring certain dangers. Therefore, in order to avoid the danger of DPF high-temperature exhaust regeneration to surrounding personnel, animals and flammable and explosive environments, it is necessary to collect information about the surrounding environment before DPF regeneration to determine whether the current environment is suitable for regeneration and issue corresponding instructions.

[0003] At present, in order to avoid the safety hazard caused by the high temperature exhaust gas generated by DPF regeneration, the driver usually manually determines the DPF regeneration time by judging the surrounding environment. This method may cause uncertain factors such as driver carelessness, blind spots, and animals approaching suddenly, which may cause danger. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present application proposes a vehicle-mounted DPF regeneration control method and device, which takes into account the possible dangers caused by the high-temperature exhaust gas generated during the regeneration process, judges whether the vehicle-mounted DPF regeneration is suitable according to the current environment, and issues corresponding instructions; it can avoid the danger of DPF high-temperature exhaust gas regeneration behavior to surrounding people, animals and flammable and explosive environments, and ensure that the DPF regeneration process is always in a safe environment.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A DPF regeneration control method comprises the following steps:

[0007] S1. Obtain the distance l between the obstacle and the particulate filter within the DPF regeneration range a ;

[0008] S2. Setting the first distance threshold d 1 and the second distance threshold d 2 , according to l a With d 1 and d 2 The size relationship between them determines whether to perform DPF regeneration. If 0<l a <d 1 , DPF prohibits regeneration; if l a >d 2 , perform DPF regeneration; if d 1 <l a <d 2 , then it is necessary to judge the type of obstacle;

[0009] S3. Determine the type of obstacle based on the temperature and image information of the obstacle; the types of obstacles include common obstacles, fixed heat sources, animals, and flammable and explosive objects;

[0010] S4, in d 1 <l a <d 2 Within the interval, according to the type of obstacle, the DPF regeneration judgment logic is: if the obstacle is a fixed heat source or a common obstacle, the current DPF regeneration index is calculated according to the current average temperature T of the heat source and the size of the obstacle. The calculation formula is:

[0011]

[0012] is the DPF regeneration index; T is the current average temperature of the heat source, in °C; V is the obstacle volume, in mm 3 ; ε is the product of the average temperature and volume of the obstacle at the critical time of DPF regeneration, unit: ℃·mm 3 ;

[0013] If the DPF regeneration index DPF prohibits regeneration;

[0014] If the DPF regeneration index DPF regenerates and emits a warning tone;

[0015] If the obstacle is an animal or flammable or explosive object, the environmental status processor will transmit a warning message to the driver, who will decide whether to regenerate. If the driver confirms that the surrounding environment is safe, he will manually decide whether the DPF should regenerate. If it is confirmed that the regeneration alarm device will emit a safety prompt sound. If the driver chooses to prohibit regeneration or does not take any action, the DPF prohibits regeneration.

[0016] Furthermore, the first distance threshold d 1and the second distance threshold d 2 The setting method is:

[0017]

[0018] d 2 =1.5d 1

[0019] Among them, t is the entire DPF regeneration cycle time, unit s; l is the length of the DPF particulate trap, unit mm; Δt is the environmental safety time, unit s; m is the wheelbase of the vehicle equipped with this device, unit mm; n is the wheelbase of the vehicle equipped with this device, unit mm.

[0020] Furthermore, the method for determining whether the obstacle is a heat source in S3 is:

[0021] Set the heat source temperature threshold to T 1 , the average temperature T of the obstacle in the thermal image of the obstacle collected by the thermal imaging module and the heat source temperature threshold T 1 Compare; if the average temperature of the obstacle T is less than T 1 , then the obstacle is judged to be a non-heat source; if the average temperature of the obstacle T is greater than or equal to T 1 , then the obstacle is judged to be a heat source.

[0022] Furthermore, the method for determining whether the obstacle is a fixed heat source or an animal body in S3 is: setting the highest body temperature of common animals T 2 , and at the same time, the change value of the pixel points in the background image of the two previous and next frames of thermal imaging images is combined to make a judgment. The judgment basis is as follows:

[0023] If T 1 ≤T, and |P (x，y，t) -P (x，y，t-1) |<A, then the heat source is judged to be the fixed heat source;

[0024] If T 1 ≤T≤T 2 And |P (x，y，t) -P (x,y,t-1) |≥A, n≥3, then the heat source is judged to be an animal body;

[0025] Among them, T is the current average temperature of the heat source, P (x，y，t) is the background image pixel at the current shooting moment, P (x,y,t-1) is the background pixel at the next shooting moment, A is the image background pixel change threshold, and n is the number of consecutive shootings.

[0026] Furthermore, in S3, it is determined whether the obstacle is an ordinary obstacle or an inflammable or explosive object. The determination method is:

[0027] The characteristic shapes and sizes of inflammable and explosive objects are collected to build several mathematical models; the collected thermal imaging images of obstacles are used as the input of the inflammable and explosive object comparison model and the model comparison is performed. When the model overlap rate between the obstacle and a certain inflammable and explosive object in the database is higher than 75%, it is considered that the comparison is successful and the obstacle is an inflammable and explosive object, otherwise the obstacle is an ordinary obstacle.

[0028] Furthermore, the continuous sampling period of the entire DPF regeneration judgment stage is set to Tc seconds, and the sampling will continue during the DPF regeneration process. The period during the DPF regeneration process is Second.

[0029] A DPF regeneration control device comprises a radar ranging module, a heat source imaging module, an image recognition and judgment module, a DPF environment state processing controller, and an alarm device; the radar ranging module is installed at a position around the exhaust port of a vehicle body, and is used to detect whether there is an obstacle within the DPF regeneration range in the exhaust direction; the heat source imaging module is installed at the rear of the exhaust pipe, and collects thermal imaging images of obstacles detected by the radar; the communication ports of the image recognition and judgment module are respectively connected to the radar ranging module and the heat source imaging module, and are used to receive obstacle distance information input by the radar ranging module and obstacle thermal imaging images input by the heat source imaging module, and the image recognition and judgment module judges the type of the obstacle based on the thermal imaging images; the types of obstacles include common obstacles, fixed heat sources, animal bodies, and inflammable and explosive objects; the DPF environment state processing controller receives the final obstacle judgment result of the image recognition and judgment module, and based on a first distance threshold d 1 and the second distance threshold d 2 The regeneration judgment logic within the range executes the corresponding instructions; the alarm device receives the control instructions of the DPF environmental status processing controller and issues a corresponding alarm.

[0030] Further, the DPF regeneration range is set as follows: the vehicle exhaust direction is the x-axis, the vertical vehicle body is the y-axis as the coordinate system, and the center position of the particle trap is the coordinate origin (0, 0) in the coordinate system; the first distance threshold d 1 and the second distance threshold d 2 The DPF regeneration range is determined for the radius.

[0031] Beneficial effects of the present invention:

[0032] The present invention provides a new vehicle-mounted DPF regeneration control method and device, which is used to determine whether the current environment is suitable for vehicle-mounted DPF regeneration and issue corresponding instructions. When the amount of particulate matter captured by the DPF reaches a certain limit and the DPF needs to be regenerated, the present invention collects the vehicle-mounted DPF and the surrounding environment information of the exhaust pipe based on radar ranging, heat source imaging, image recognition and judgment technology, and transmits it to the ESCU synchronously. According to the proposed DPF regeneration control method, it is decided whether to regenerate the DPF and issue corresponding instructions. Fully consider the uncertain factors such as driver carelessness, blind spots in vision, and animals that suddenly approach, so as to avoid the danger of DPF high-temperature exhaust regeneration to surrounding personnel, animals and flammable and explosive environments, and ensure that the DPF regeneration process is always in a safe environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of setting the DPF regeneration distance threshold of the present invention.

[0034] Figure 2 It is a DPF regeneration logic judgment flow chart of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] A DPF regeneration control device comprises a radar ranging module, a heat source imaging module, an image recognition and judgment module, a DPF environment state processing controller, and an alarm device.

[0037] The radar ranging module is installed around the exhaust port of the vehicle body to detect whether there are obstacles within the DPF regeneration range in the exhaust direction; the DPF regeneration range described in this application is set as follows: Figure 1 The vehicle exhaust direction is taken as the x-axis, the vertical vehicle body is taken as the y-axis as the coordinate system, and the center position of the particulate collector is taken as the origin (0, 0) in the coordinate system; the first distance threshold d is set based on the vehicle's wheelbase m, wheelbase n and other information 1 and the second distance threshold d 2 : Taking the first distance threshold d 1 and the second distance threshold d 2 Determine the DPF regeneration range for the radius; set the first distance threshold d 1 and the second distance threshold d 2 The method is specifically expressed as:

[0038]

[0039] d 2 =1.5d1

[0040] Among them, t is the entire DPF regeneration cycle time, unit s; l is the length of the DPF particulate trap, unit mm; Δt is the environmental safety time, which is 0.8 to 0.95 times the DPF regeneration cycle time. The specific value of Δt can be selected based on the sampling period, the fastest moving speed of common animals, and the vehicle use environment, unit s; m is the wheelbase of the vehicle equipped with this device, unit mm; n is the wheelbase of the vehicle equipped with this device (when the carrying vehicle is a trailer, the wheelbase in the formula refers to the distance between the first and rear axles of the towing part), unit mm.

[0041] In 0-d 1 Within the range, DPF regeneration should be prohibited due to the high risk factor of high temperature exhaust gas regeneration due to the close distance;

[0042] In d 1 -d 2 Within the range, the type of obstacles within the range should be judged, and the regeneration judgment basis should be further selected according to the obstacle type.

[0043] In greater than d 2 Within the range, the distance is far, so DPF regeneration can be performed directly.

[0044] The thermal imaging module is installed behind the exhaust pipe to collect thermal images of obstacles detected by the radar.

[0045] The communication ports of the image recognition and judgment module are respectively connected to the radar ranging module and the heat source imaging module, and are used to receive the obstacle distance information input by the radar ranging module and the obstacle thermal imaging image input by the heat source imaging module. The image recognition and judgment module judges the type of the obstacle based on the thermal imaging image; the types of obstacles include common obstacles, fixed heat sources, animal bodies and inflammable and explosive objects;

[0046] The DPF environment state processing controller (ESCU) receives the final obstacle judgment result of the image recognition and judgment module, and according to the first distance threshold d 1 and the second distance threshold d 2 The regeneration judgment logic within the range executes the corresponding instructions.

[0047] The alarm device receives control instructions from the DPF environment status processing controller and issues corresponding alarms.

[0048] Based on the above-mentioned DPF regeneration control device, the present application also proposes a DPF regeneration control method, and the specific steps of the method are as follows:

[0049] S1. Use radar to obtain the distance between the obstacle and the particulate filter within the DPF regeneration range. Assume the radar position is (x m ,ym ), the coordinate position of the obstacle closest to the origin in the horizontal direction obtained by the radar is (x n ,y n ), then the horizontal distance between the obstacle and the coordinate origin (particle collector) is l a , unit is mm, size: l a =x m +x n , if the radar is at d 2 No obstacles are detected in the area, record l a =0, DPF regeneration can be performed.

[0050] S2, if 0<l a <d 1 , the obstacle is at the first distance threshold d 1 Within the range, DPF regeneration is prohibited;

[0051] If l a >d 2 , that is, when the obstacle is at the second distance threshold d 2 Outside the range, DPF regeneration can be performed.

[0052] If d 1 <l a <d 2 , then it is necessary to judge the type of obstacle;

[0053] S3. The method for determining the type of obstacle is:

[0054] S3.1. First, set the heat source temperature threshold to T 1 , the average obstacle temperature T collected by the thermal imaging module and the heat source temperature threshold T 1 Compare; if the average temperature of the obstacle T is less than T 1 , then the obstacle is judged to be a non-heat source; if the average temperature of the obstacle T is greater than or equal to T 1 , then the obstacle is judged to be a heat source.

[0055] S3.2. Further determine whether the heat source obstacle determined in S3.1 is a fixed heat source or an animal body. The animals referred to in this patent are common animals in daily life. The highest body temperature of common animals is set to T 2 , T 2 The reference range is 39℃~45℃; at the same time, the change value of the pixel points in the background image of the two frames of thermal imaging is combined to make a judgment. The judgment basis is as follows:

[0056] If T 1 ≤T, and |P (x，y，t) -P (x,y,t-1) |<A, then the heat source is judged to be the fixed heat source;

[0057] If T 1 ≤T≤T 2 And |P (x，y，t) -P (x,y,t-1) |≥A, n≥3, then the heat source is judged to be an animal body;

[0058] Among them, T is the current average temperature of the heat source, P (x，y，t) is the background image pixel at the current shooting moment, P (x,y,t-1) is the background pixel at the next shooting moment, A is the image background pixel change threshold, and n is the number of consecutive shootings.

[0059] S3.3: Further determine whether the non-heat source obstacle determined in S3.1 is an ordinary obstacle or a flammable or explosive object. The determination method is as follows:

[0060] S3.3.1. The inflammable and explosive materials described in this application include daily items such as haystacks, paper, coal piles, oil tanks, liquefied gas cylinders, quilts, etc., but are not limited to the above items. Several mathematical models are built based on the characteristic shapes and sizes of the above inflammable and explosive materials and stored in the image recognition and judgment module. Taking gas tanks as an example, common gas tanks have three specifications of 320*620, 249*413, and 407*1193mm. Except for the size, the shapes are basically the same. Mathematical models of these three gas tanks are built in the modeling software and stored in the image recognition and judgment module.

[0061] S3.3.2. The thermal imaging image of the obstacle collected by the heat source imaging module is used as the input of the flammable and explosive material comparison model. The image recognition and judgment module performs model comparison. When the overlap rate with the gas tank model in the module is higher than 75%, it is considered that the comparison is successful and the obstacle belongs to a gas tank. Otherwise, the obstacle is an ordinary obstacle.

[0062] S4, in d 1 <l a <d 2 Within the range, according to the type of obstacle, the DPF regeneration judgment logic is as follows:

[0063] If the obstacle is a fixed heat source or a common obstacle, the current DPF regeneration index is calculated based on the current average temperature T of the heat source and the size of the obstacle. The specific calculation formula is:

[0064]

[0065] is the DPF regeneration index; T is the current average temperature of the heat source, in °C; v is the obstacle volume, in mm 3 ; ε is the product of the average temperature and volume of the obstacle at the critical time of DPF regeneration, unit: ℃·mm 3 .

[0066] If the DPF regeneration index DPF prohibits regeneration;

[0067] If the DPF regeneration index DPF regenerates and emits a warning tone;

[0068] If the obstacle is an animal or flammable or explosive object, the environmental status processor will send a warning message to the driver, who will decide whether to regenerate. The driver confirms that the surrounding environment is safe and manually decides whether the DPF should regenerate. If it is confirmed that the regeneration alarm device will emit a safety prompt sound; if the driver chooses to prohibit regeneration or does not do anything, the DPF prohibits regeneration.

[0069] In this application, the continuous sampling period of the entire DPF regeneration judgment stage is set to Tc seconds. In order to improve the responsiveness of the DPF stop regeneration command, continuous sampling will also be performed during DPF regeneration. The period at this time is Seconds, T c It can be determined according to the actual vehicle environment and the processor operating speed. During the regeneration process, before receiving new instructions, the regeneration command will be executed until the DPF regeneration is completed.

[0070] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A DPF regeneration control method, characterized in that: The steps include: S1. Obtain the distance l between the obstacle and the particulate filter within the DPF regeneration range a ; S2. Set the first distance threshold d1 and the second distance threshold d2, and based on l a judge whether to perform DPF regeneration according to the size relationship between and d1 and d2. If 0 < l a < d1, DPF regeneration is prohibited; if l a > d2, perform DPF regeneration; if d1 < l a < d2, it is necessary to judge the type of obstacle; S3. Determine the type of obstacle based on the temperature and image information of the obstacle; the types of obstacles include common obstacles, fixed heat sources, animals, and flammable and explosive objects; S4. When d1 < l a <Within the d2 interval, according to the type of obstacle, the DPF regeneration judgment logic is as follows: If the obstacle belongs to a fixed heat source or a common obstacle, calculate the current DPF regeneration index based on the current average temperature T of the heat source and the size of the obstacle. The calculation formula is: is the DPF regeneration index; T is the current average temperature of the heat source, in °C; V is the obstacle volume, in mm 3 ; ε is the product of the average temperature and volume of the obstacle at the critical time of DPF regeneration, unit: ℃·mm 3 ; If the DPF regeneration index DPF prohibits regeneration; If the DPF regeneration index DPF regenerates and emits a warning tone; If the obstacle is an animal or flammable or explosive object, the environmental status processor will transmit the warning information to the driver, who will decide whether to regenerate. The driver will confirm that the surrounding environment is safe and manually decide whether to regenerate the DPF. If the driver confirms that the regeneration alarm device emits a safety prompt sound. If the driver chooses to prohibit regeneration or does not perform any operation, the DPF prohibits regeneration. The setting method of the first distance threshold d1 and the second distance threshold d2 is: d2=1.5d1 Among them, t is the entire DPF regeneration cycle time, unit s; l is the length of the DPF particulate trap, unit mm; Δt is the environmental safety time, unit s; m is the wheelbase of the vehicle equipped with this device, unit mm; n is the wheelbase of the vehicle equipped with this device, unit mm.

2. A DPF regeneration control method according to claim 1, characterized in that: The method for determining whether the obstacle is a heat source in S3 is: setting the heat source temperature threshold as T1, and comparing the obstacle average temperature T collected by the heat source imaging module with the heat source temperature threshold T1; If the average temperature T of the obstacle is less than T1, the obstacle is judged to be a non-heat source; if the average temperature T of the obstacle is greater than or equal to T1, the obstacle is judged to be a heat source.

3. A DPF regeneration control method according to claim 1, characterized in that: The method for determining whether the obstacle is a fixed heat source or an animal body in S3 is as follows: set the highest body temperature T2 of common animals, and make a judgment based on the change value of the pixel points in the background image of the previous and next two frames of thermal imaging. The judgment is based on the following: If T1 ≤ T and |P (x,y,t) - P (x,y,t-1) | < A, then it is determined that this heat source is this fixed heat source; If T1≤T≤T2 and |P (x,y,t) -P (x,y,t-1) |≥A, n≥3, then the heat source is judged to be an animal body; Among them, T is the current average temperature of the heat source, P (x,y,t) is the background image pixel at the current shooting moment, P (x,y,t-1) is the background pixel at the next shooting moment, A is the image background pixel change threshold, and n is the number of consecutive shootings.

4. A DPF regeneration control method according to claim 1, characterized in that: In S3, it is determined whether the obstacle is an ordinary obstacle or an inflammable and explosive object. The determination method is as follows: a number of mathematical models are built based on the characteristic shapes and sizes of inflammable and explosive objects; the collected thermal imaging images of the obstacle are used as the input of the inflammable and explosive object comparison model and the model comparison is performed. When the model overlap rate between the obstacle and a certain inflammable and explosive object in the database is higher than 75%, it is considered that the comparison is successful and the obstacle is an inflammable and explosive object. Otherwise, the obstacle is an ordinary obstacle.

5. A DPF regeneration control method according to any one of claims 1 to 4, characterized in that: Set the continuous sampling period of the entire DPF regeneration judgment phase to T c seconds. Sampling will continue during the DPF regeneration process. The cycle of the DPF regeneration process is Second.

6. A DPF regeneration control device based on the DPF regeneration control method according to claim 5, characterized in that: It includes a radar ranging module, a heat source imaging module, an image recognition and judgment module, a DPF environment status processing controller, and an alarm device; the radar ranging module is installed at a position around the exhaust port of the vehicle body, and is used to detect whether there is an obstacle within the DPF regeneration range in the exhaust direction; the heat source imaging module is installed behind the exhaust pipe, and collects thermal imaging images of obstacles detected by the radar; the communication ports of the image recognition and judgment module are respectively connected to the radar ranging module and the heat source imaging module, and are used to receive obstacle distance information input by the radar ranging module and obstacle thermal imaging images input by the heat source imaging module, and the image recognition and judgment module determines the type of the obstacle based on the thermal imaging image; the types of obstacles include ordinary obstacles, fixed heat sources, animal bodies, and inflammable and explosive objects; The DPF environment status processing controller receives the final obstacle judgment result of the image recognition and judgment module, and executes corresponding instructions based on the regeneration judgment logic within the range of the first distance threshold d1 and the second distance threshold d2; the alarm device receives the control instruction of the DPF environment status processing controller and issues corresponding warnings.

7. A DPF regeneration control device according to claim 6, characterized in that: The DPF regeneration range is set as follows: the vehicle exhaust direction is the x-axis, the vertical vehicle body is the y-axis as the coordinate system, and the center position of the particulate collector is the coordinate origin (0, 0) in the coordinate system; the DPF regeneration range is determined by the first distance threshold d1 and the second distance threshold d2 as the radius.

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