Vehicle DPF regeneration temperature control method, device and system

Abstract

The invention discloses an automotive DPF regeneration temperature control method, device and system. The method comprises the following steps that the current carbon loading amount is obtained, and a temperature correction coefficient is determined based on the current carbon loading amount; acquiring the current working condition of the engine and determining a first target temperature and a second target temperature according to the current working condition of the engine; determining a third target temperature according to the temperature correction coefficient, the first target temperature and the second target temperature; and according to the third target temperature, the in-cylinder back-spraying oil quantity is calculated. According to the scheme, when the first target temperature and the second target temperature are respectively no-load and full-load of the DPF, the target temperature is controlled to be relatively low when the DPF is full-load, and the target temperature is controlled to be relatively high when the DPF is no-load, so that the DPF cannot be damaged due to sharp temperature rise after the DPF is full of carbon and enters regeneration; and the temperature can be gradually increased after actual carbon particles in the DPF are gradually reduced, so that it is ensured that the DPF has high regeneration efficiency, it is finally ensured that regeneration of the DPF is safely and effectively completed, and normal operation of an engine is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of regeneration temperature control, and in particular relates to a method, device and system for controlling the regeneration temperature of a vehicle DPF. Background Art

[0002] In the exhaust system of the National VI engine, the particulate filter DPF captures soot in the exhaust gas and stores it inside the carrier. When the captured soot reaches the regeneration threshold, the vehicle triggers regeneration after the regeneration-related environmental conditions are met to burn and remove the soot captured inside the DPF, thereby ensuring the normal operation of the engine. During DPF regeneration, since the post-injection amount in the regeneration cylinder is calculated by the target temperature closed loop, the actual amount of soot captured inside the carrier at the time of DPF regeneration triggering cannot be accurately determined. At this time, if the target temperature is too high, the calculated post-injection amount in the cylinder is too much, and there is a risk of damage to the DPF. If it is too low, the regeneration time will be too long or even abnormally exited. The regeneration cannot effectively remove the soot captured inside the carrier to ensure engine performance. The existing technology determines whether to trigger regeneration by calibrating the model carbon load to reach the threshold, including the original exhaust model, mileage model, pressure difference model, etc.; due to the different operating conditions of each vehicle model, the actual amount of soot captured inside the carrier at the time of DPF triggering regeneration is also different, and the temperature during regeneration is also very different.

[0003] With the existing methods, the regeneration efficiency and safety cannot be effectively balanced. Summary of the invention

[0004] In order to solve the problem that the efficiency and safety of existing regeneration control cannot be taken into account at the same time, the present invention proposes a vehicle DPF regeneration temperature control method, device and system.

[0005] The objective of the present invention is achieved through the following technical solutions: The first aspect of the present invention discloses a method for controlling the regeneration temperature of a vehicle DPF, comprising the following steps: Obtaining a current carbon loading and determining a temperature correction factor based on the current carbon loading; Acquire the current working condition of the engine and determine the first target temperature and the second target temperature from a first engine working condition and temperature relationship table and a second engine working condition and temperature relationship table according to the current working condition of the engine, wherein the first engine working condition and temperature relationship table records the corresponding relationship between the engine working condition and the temperature when the engine is idling, and the second engine working condition and temperature relationship table records the corresponding relationship between the engine working condition and the temperature when the engine is fully loaded; Determining a third target temperature according to the temperature correction coefficient, the first target temperature and the second target temperature; The amount of oil to be post-injected into the cylinder is calculated based on the third target temperature.

[0006] The second aspect of the present invention discloses a vehicle DPF regeneration temperature control device, comprising a memory and a controller which are communicatively connected in sequence, wherein the memory stores a computer program, and the controller is used to read the computer program and execute the vehicle DPF regeneration temperature control method described in the first aspect.

[0007] The third aspect of the present invention discloses a vehicle DPF regeneration temperature control system, comprising: a particulate filter for capturing exhaust gases from the vehicle; engine; A control unit is coupled to the particulate filter and the engine so that when the amount of soot in the exhaust material captured by the particulate filter reaches a regeneration threshold, a vehicle DPF regeneration temperature control method described in the first aspect is used to obtain the amount of oil post-injected into the cylinder and control the engine operation with the amount of oil post-injected into the cylinder.

[0008] The beneficial effects of the present invention are: The first target temperature and the second target temperature of the present invention are respectively when the DPF is unloaded and fully loaded. The target temperature is controlled to be lower when the DPF is fully loaded, and higher when the DPF is unloaded. This can prevent the DPF from being damaged due to a sharp increase in temperature after the full carbon enters regeneration, and can gradually increase the temperature after the actual carbon particles inside the DPF gradually decrease, thereby ensuring that the DPF has a higher regeneration efficiency, and ultimately ensuring that the DPF completes regeneration safely and effectively, thereby ensuring the normal operation of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 The figure is a flow chart of the vehicle DPF regeneration temperature control method of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0014] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0015] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0016] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0017] The first aspect of the present invention discloses a method for controlling the regeneration temperature of a DPF for a vehicle, which can be, but is not limited to, executed by a DPF regeneration temperature control device for a vehicle, which can be an existing control unit ECU. Specifically, the fault diagnosis method is triggered when the amount of soot in the exhaust material captured by the particulate filter reaches a regeneration threshold, such as Figure 1 As shown, it includes the following steps S01 to S04. It should be noted that the step identifiers in this solution are only for the convenience of explaining the method and do not constitute a limitation on the sequence. The sequence of each step is based on its language description and the sequence of each signal.

[0018] Step S01, obtaining a current carbon loading and determining a temperature correction coefficient based on the current carbon loading.

[0019] Specifically, in this step, the temperature correction coefficient can be determined from a correction unit curve in the carbon loading model according to the current carbon loading, and the correction unit curve represents the corresponding relationship between the carbon loading and the temperature correction coefficient.

[0020] Among them, on the correction unit curve, as the carbon loading decreases, the temperature correction coefficient gradually increases.

[0021] Step S02, obtaining the current operating condition of the engine and determining the first target temperature and the second target temperature from a first engine operating condition and temperature relationship table and a second engine operating condition and temperature relationship table according to the current operating condition of the engine, wherein the first engine operating condition and temperature relationship table records the corresponding relationship between the engine operating condition and the temperature when the engine is idling, and the second engine operating condition and temperature relationship table records the corresponding relationship between the engine operating condition and the temperature when the engine is fully loaded.

[0022] The first engine operating condition and temperature relationship table and the second engine operating condition and temperature relationship table of this step are the corresponding relationships between the engine operating conditions and temperatures calibrated when the engine is idling and fully loaded, respectively. Under the same operating condition, that is, the engine is at the same speed and fuel volume, the temperature is lower when it is idling than when it is fully loaded.

[0023] Step S03: determining a third target temperature according to the temperature correction coefficient, the first target temperature and the second target temperature.

[0024] Specifically, first calculate the first target temperature T1 des and the second target temperature T2 des The temperature difference is obtained by calculating the product of the temperature difference and the temperature correction coefficient and the sum of the second target temperature to obtain the third target temperature T outdes .

[0025] That is: T outdes =T2 des + (T1 des -T2 des )×fac(x) fac(x) is the temperature correction coefficient.

[0026] Step S04: Calculate the amount of post-injection oil in the cylinder according to the third target temperature.

[0027] The method of calculating the amount of oil to be post-injected into the cylinder according to the target temperature is a prior art, so it will not be described in detail in this solution.

[0028] With the above scheme, the correction coefficient curve of the carbon load model value gradually increases with the decrease of carbon load. When the DPF triggers regeneration, the ECU calculates the final third target temperature of the current regeneration in real time based on the temperature correction coefficient of the current carbon load and the first target temperature and the second target temperature. The ECU then calculates the amount of post-injection oil in the cylinder in real time according to the third target temperature and injects it, thereby achieving the purpose of gradually increasing the temperature with the combustion of the model during the regeneration process. The low early target temperature control effectively prevents the actual carbon explosion in the particulate filter when regeneration just begins, causing damage to the DPF. At the same time, the later temperature increase can effectively improve the DPF regeneration efficiency and avoid damage to the DPF due to blockage.

[0029] The method of the present invention has the advantages of being able to effectively control the temperature during the active regeneration of the DPF to gradually increase from low to high, thereby effectively preventing damage to the DPF.

[0030] The second aspect of the present invention discloses a vehicle DPF regeneration temperature control device, including a memory and a controller that are sequentially connected in communication, the memory stores a computer program, and the controller is used to read the computer program and execute a vehicle DPF regeneration temperature control method described in the first aspect. Specifically, the memory may include, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a flash memory (Flash Memory), a first-in-first-out memory (FIFO) and / or a first-in-last-out memory (FILO), etc.; the controller may not be limited to a microcontroller of the STM32F105 series. In addition, the computer device may also include, but is not limited to, a power supply unit, a display screen and other necessary components.

[0031] Specifically, the memory also stores a correction unit curve of the carbon load model, a first engine operating condition and temperature relationship table, and a second engine operating condition and temperature relationship table. The first engine operating condition and temperature relationship table records the correspondence between the engine operating condition and the temperature when the engine is idling, and the second engine operating condition and temperature relationship table records the correspondence between the engine operating condition and the temperature when the engine is fully loaded. The correction unit curve represents the correspondence between the carbon load and the temperature correction coefficient. As the carbon load decreases on the correction unit curve, the temperature correction coefficient gradually increases.

[0032] By adopting the above device, the temperature correction coefficient of the direct correction unit curve is used to correct the regeneration target temperature. The temperature correction coefficient increases with the decrease of carbon loading, thereby ensuring that when the DPF enters regeneration, the regeneration temperature decreases from high to bottom as the carbon loading decreases, while the actual temperature gradually increases from low to high until the regeneration is successful, ensuring that the fully loaded DPF will not be damaged due to a sudden sharp increase in temperature after entering regeneration, and at the same time, it can ensure that the DPF has a higher regeneration efficiency after gradually raising the temperature, and ultimately ensure that the DPF completes regeneration safely and effectively.

[0033] The third aspect of the present invention discloses a vehicle DPF regeneration temperature control system, comprising a particulate trap, an engine and a control unit, wherein the particulate trap is used to capture the emission substances of the vehicle; the control unit can be a vehicle DPF regeneration temperature control device of the second aspect, or it can be an existing vehicle ECU, and the control unit is coupled to the particulate trap and the engine, so that when the amount of soot in the emission substances captured by the particulate trap reaches a regeneration threshold, a vehicle DPF regeneration temperature control method described in the first aspect is used to obtain the amount of post-injected oil in the cylinder and control the engine operation with the amount of post-injected oil in the cylinder.

[0034] The operating principles of the devices and systems disclosed in the second and third aspects of the present invention are detailed in the first aspect and will not be elaborated here.

[0035] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for controlling the regeneration temperature of a vehicle DPF, characterized in that: The following steps are involved: Obtaining a current carbon loading and determining a temperature correction factor based on the current carbon loading; Acquire the current working condition of the engine and determine the first target temperature and the second target temperature from a first engine working condition and temperature relationship table and a second engine working condition and temperature relationship table according to the current working condition of the engine, wherein the first engine working condition and temperature relationship table records the corresponding relationship between the engine working condition and the temperature when the engine is idling, and the second engine working condition and temperature relationship table records the corresponding relationship between the engine working condition and the temperature when the engine is fully loaded; Determining a third target temperature according to the temperature correction coefficient, the first target temperature and the second target temperature; The amount of oil post-injected into the cylinder is calculated based on the third target temperature.

2. A vehicle DPF regeneration temperature control method according to claim 1, characterized in that: Determining the temperature correction coefficient based on the current carbon loading includes: The temperature correction coefficient is determined from a correction unit curve in the carbon loading model according to the current carbon loading, wherein the correction unit curve represents the corresponding relationship between the carbon loading and the temperature correction coefficient.

3. A vehicle DPF regeneration temperature control method according to claim 2, characterized in that: On the correction unit curve, as the carbon loading decreases, the temperature correction coefficient gradually increases.

4. A vehicle DPF regeneration temperature control method according to claim 1, characterized in that: Determining the third target temperature according to the temperature correction coefficient, the first target temperature and the second target temperature includes: Calculating the difference between the first target temperature and the second target temperature to obtain a temperature difference; The product of the temperature difference and the temperature correction coefficient and the sum of the second target temperature are calculated to obtain a third target temperature.

5. A vehicle DPF regeneration temperature control device, characterized in that: It comprises a memory and a controller which are communicatively connected in sequence, wherein the memory stores a computer program, and the controller is used to read the computer program and execute a vehicle DPF regeneration temperature control method as described in any one of claims 1 to 4.

6. A vehicle DPF regeneration temperature control method according to claim 5, characterized in that: The memory also stores a correction unit curve of the carbon load model, a first engine operating condition and temperature relationship table, and a second engine operating condition and temperature relationship table. The first engine operating condition and temperature relationship table records the corresponding relationship between the engine operating condition and the temperature when the engine is idling, and the second engine operating condition and temperature relationship table records the corresponding relationship between the engine operating condition and the temperature when the engine is fully loaded. The correction unit curve represents the corresponding relationship between the carbon load and the temperature correction coefficient. As the carbon load decreases on the correction unit curve, the temperature correction coefficient gradually increases.

7. A vehicle DPF regeneration temperature control system, characterized in that: include: a particulate filter for capturing exhaust gases from the vehicle; engine; A control unit, wherein the control unit is coupled to the particulate filter and the engine so that when the amount of soot in the exhaust material captured by the particulate filter reaches a regeneration threshold, a vehicle DPF regeneration temperature control method as described in any one of claims 1 to 4 is used to obtain the amount of oil post-injected into the cylinder and control the engine operation with the amount of oil post-injected into the cylinder.

Images