Method and system for determining carbon loading capacity of DPF (diesel particulate filter)

Abstract

The invention discloses a DPF carbon loading capacity determination method and system, and the method comprises the steps: judging whether a vehicle working condition corresponding to the current flow resistance of a DPF belongs to a preset flow resistance incredible working condition or not: if not, filtering the current flow resistance, and determining the current carbon loading capacity of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon loading capacity relation table; if yes, the current flow resistance is not filtered, and the current carbon loading capacity of the DPF is determined based on the flow resistance obtained after last filtering and a pre-calibrated flow resistance-carbon loading capacity relation table; the flow resistance untrusted working condition is an instantaneous working condition. According to the method and the device, when the vehicle working condition belongs to the preset flow resistance untrusted working condition, the current carbon load is determined by directly using the flow resistance filtered last time in combination with the pre-calibrated flow resistance-carbon load relation table instead of using the flow resistance under the working condition to determine the carbon load; the flow resistance calculation error caused by the inaccurate measurement of the differential pressure and the exhaust volume flow of the DPF is effectively avoided, so that the accuracy of the carbon loading capacity calculation is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method and system for determining the carbon load of a DPF. Background Art

[0002] Diesel engines are widely used in the transportation sector due to their excellent power performance, stability and fuel economy. In order to reduce particulate matter emissions from diesel engines, a diesel particulate filter (DPF) is installed in the exhaust system of a diesel engine. This filter made of ceramics can capture particulate emissions, mainly through mechanisms such as diffusion, inertial sedimentation or linear interception, to capture particulate matter before it is emitted into the atmosphere, thereby purifying the particulate matter in the exhaust gas, with a purification efficiency of 70% to 90%. The carbon load of the DPF, that is, the amount of carbon particulate matter captured inside it, is a key parameter for evaluating the service life and filtering effect of the DPF. Existing technologies calculate the flow resistance of the DPF by measuring the pressure difference and exhaust volume flow of the DPF, and then determine its carbon load based on the flow resistance.

[0003] To improve the accuracy of DPF carbon loading, existing technologies divide exhaust temperature into different ranges through exhaust temperature sensors, and assign different filtering times to pressure differentials and exhaust volume flow rates in different exhaust temperature ranges to improve the accuracy of pressure differential carbon loading at different exhaust temperatures. However, due to the material and characteristics of the DPF carrier, the sensitivity of its pressure differential and temperature characteristics are different. The rationality of the exhaust temperature range setting is difficult to grasp and requires a large amount of experimental verification. The accuracy of the increased pressure differential cannot be guaranteed.

[0004] Furthermore, the existing technology reduces the deviation problem in the process of obtaining the PDF carbon load by setting a correction value. For example, one existing technology proposes a method for correcting the DPF pressure difference measurement value, which specifically includes: obtaining a first DPF pressure difference measurement value after the vehicle is powered off, and judging whether a first correction condition is met based on the first DPF pressure difference measurement value; when the first correction condition is met, determining a correction coefficient based on the first DPF pressure difference measurement value; when the vehicle is powered on next time, obtaining a second DPF pressure difference measurement value before the engine is started, and judging whether a second correction condition is met based on the second DPF pressure difference measurement value; when the second correction condition is met, determining a pressure difference correction value based on the correction coefficient and the first DPF pressure difference measurement value, and correcting the real-time DPF pressure difference measurement value after the vehicle is powered on based on the pressure difference correction value. For example, a prior art proposes a DPF carbon load monitoring method, which specifically includes: after the engine actively regenerates, determining whether the regeneration is complete; if the active regeneration is complete, then when the engine reaches the preset operating condition for the first time after regeneration, recording the measured value of the DPF upstream and downstream pressure difference at this time as the basic pressure difference measurement value of the current monitoring cycle; querying the DPF pressure difference MAP based on the measured value of the exhaust gas temperature and the measured value of the exhaust flow at this time, and obtaining the DPF calibrated basic pressure difference value when the DPF carbon load is zero; determining the carbon load revision coefficient of the current monitoring cycle based on the basic pressure difference measurement value of the current monitoring cycle and the calibrated basic pressure difference value; and monitoring the carbon load of the DPF based on the measured value of the exhaust gas temperature, the measured value of the exhaust flow, the measured value of the DPF upstream and downstream pressure difference, the DPF pressure difference MAP and the carbon load revision coefficient.

[0005] Although the above-mentioned existing technologies can improve the accuracy of DPF carbon loading to a certain extent, they have a common problem, that is, under specific operating conditions, such as low-load conditions, conditions where the DPF pressure difference increases rapidly, etc., the measurement results of the two key parameters of DPF pressure difference and exhaust volume flow are inaccurate, which further affects the accuracy of the calculation of flow resistance and may ultimately lead to inaccurate calculation results of carbon loading. Summary of the Invention

[0006] The present application provides a method and system for determining the carbon load of a DPF, which can solve the problem of poor accuracy in calculating the carbon load of a DPF.

[0007] To achieve the above objectives, in a first aspect, the present application provides a method for determining DPF carbon load, the method comprising: Determine whether the vehicle operating condition corresponding to the current DPF flow resistance belongs to the preset untrustworthy flow resistance condition: If not, the current flow resistance is filtered, and the current carbon load of the DPF is determined based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table.

[0008] If so, the current flow resistance is not filtered, and the current carbon load of the DPF is determined based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table.

[0009] The unreliable flow resistance operating condition is a transient operating condition.

[0010] Furthermore, in one embodiment, the unreliable flow resistance operating conditions include low load conditions, DPF pressure difference rapidly increasing conditions, OverRun conditions, low temperature conditions, engine regeneration conditions, and fault conditions.

[0011] Furthermore, in one embodiment, before determining whether the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to a preset untrustworthy flow resistance condition, the method further includes: The current flow resistance of the DPF is calculated based on the currently measured carbon-free load differential pressure, carbon-containing load differential pressure, and exhaust volume flow rate of the DPF.

[0012] Furthermore, in one embodiment, the low load condition is determined as follows: When the exhaust volume flow rate of the DPF is within a preset small exhaust volume flow rate range, the vehicle is in a low-load operating condition.

[0013] Furthermore, in one embodiment, the method for determining the DPF pressure differential rapidly increasing condition is: When the rate of change of the carbon load pressure difference of the DPF is greater than a preset upper limit of the rate of change, the vehicle is in a condition where the DPF pressure difference increases rapidly.

[0014] Furthermore, in one embodiment, the low temperature condition is determined as follows: When the exhaust temperature of the DPF is lower than a preset temperature threshold, or the duration of the exhaust temperature of the DPF being greater than or equal to the preset temperature threshold is shorter than a preset time threshold, the vehicle is in a low-temperature operating condition.

[0015] Furthermore, in one embodiment, the fault conditions include: air flow meter measurement deviation, air flow meter open circuit or short circuit, differential pressure sensor open circuit or short circuit, and unreasonable differential pressure sensor measurement value.

[0016] Furthermore, in one embodiment, the OverRun operating condition and the engine regeneration operating condition are directly identified by the vehicle's electronic control unit.

[0017] Furthermore, in one embodiment, the pre-calibrated flow resistance-carbon loading relationship table is calibrated under different driving conditions of the vehicle.

[0018] In a second aspect, based on the above-mentioned DPF carbon load determination method, the present application provides a determination system for the DPF carbon load determination method, the system comprising: The judgment module judges whether the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to a preset flow resistance untrustworthy operating condition.

[0019] The filtering module is used to filter the current flow resistance when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not belong to the preset flow resistance untrustworthy operating condition.

[0020] A carbon load module is used to determine the current carbon load of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not belong to the preset flow resistance untrustworthy operating condition. It is also used to determine the current carbon load of the DPF based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to the preset flow resistance untrustworthy operating condition.

[0021] The beneficial effects of the technical solutions provided in the embodiments of the present application include: This application accurately calculates and effectively manages the DPF's carbon load by determining whether the vehicle operating condition corresponding to the DPF's current flow resistance falls within a preset untrusted flow resistance condition (an untrusted flow resistance condition is a short-duration, transient condition). If the vehicle's operating condition does not fall within an untrusted flow resistance condition, the current flow resistance is filtered, and the current DPF's carbon load is determined based on the filtered flow resistance combined with a pre-calibrated flow resistance-carbon load relationship table. If the vehicle's operating condition falls within an untrusted flow resistance condition, the current carbon load is determined directly based on the previously filtered flow resistance combined with a pre-calibrated flow resistance-carbon load relationship table.

[0022] Because the specific unreliable flow resistance condition is transient and short-lived, it does not cause abnormal fluctuations in the actual carbon load. Specifically, under this condition, the actual carbon load remains within a normal range. However, it does affect the DPF pressure differential and exhaust volume flow measurement results, thereby affecting the accuracy of the flow resistance calculation and ultimately leading to inaccurate carbon load calculation results. In this application, when the vehicle operating condition falls under the preset unreliable flow resistance condition, the carbon load is not determined using the flow resistance under that condition. Instead, the previously filtered flow resistance is directly used in conjunction with a pre-calibrated flow resistance-carbon load relationship table to determine the current carbon load. This effectively avoids flow resistance calculation errors caused by inaccurate DPF pressure differential and exhaust volume flow measurements, thereby improving the accuracy of carbon load calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for determining DPF carbon load according to an embodiment of the present application.

[0024] Figure 2 This is a block diagram of a DPF carbon load determination system according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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 this application.

[0026] It should be noted that, while the actual carbon load remains essentially unchanged under certain specific instantaneous vehicle operating conditions, the measurement results of two key parameters, the DPF's pressure differential and exhaust volume flow rate, may be inaccurate. Since these two parameters are the fundamental data for calculating the DPF's flow resistance, inaccurate measurements will further affect the accuracy of the flow resistance calculation, which in turn is directly related to the accuracy of the DPF's carbon load. This may ultimately lead to a deviation between the calculated carbon load and the actual carbon load. Based on this, the present application proposes a DPF carbon load determination method and system that can address the common problems in the aforementioned prior art.

[0027] First, some technical terms and principles in this application are explained to facilitate those skilled in the art to understand this application.

[0028] (1) OverRun condition: When the accelerator pedal is fully released, the engine is driven by the kinetic energy of the vehicle. In this condition, the throttle of the engine is closed and the engine no longer sprays fuel, which plays a role of auxiliary braking. It usually occurs in the following situations: Downhill driving: When the vehicle is driving downhill, due to the effect of gravity, the vehicle will accelerate and glide, and the engine is in the OverRun condition.

[0029] Braking or coasting: When the vehicle is braking or coasting, the engine no longer provides power output, but the inertia of the vehicle drives the engine to run.

[0030] Release the accelerator: When the driver releases the accelerator pedal, the engine enters the OverRun state.

[0031] (2) Engine regeneration condition: During the operation of a diesel engine, through specific control strategies and operating conditions, the engine's after-treatment system (such as the diesel particulate filter DPF, selective catalytic reducer SCR, etc.) enters a special operating state to remove carbon deposits, ash or other pollutants in the after-treatment system, thereby restoring its normal function.

[0032] (3) The principle of calculating the DPF carbon load by using the pressure difference and flow resistance: First, measure the air pressure difference under the DPF no-load condition, and measure the DPF carbon load pressure difference through the pressure difference sensors at both ends of the DPF. Based on the air pressure difference, the carbon load pressure difference, and the measured exhaust volume flow rate, calculate the DPF flow resistance, look up the preset flow resistance-carbon load relationship table, and obtain the carbon load corresponding to the flow resistance.

[0033] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0034] In a first aspect, an embodiment of the present application provides a method for determining the carbon load of a DPF.

[0035] In one embodiment, see Figure 1 As shown, the above-mentioned carbon load determination method includes: S1. Determine whether the vehicle operating condition corresponding to the current DPF flow resistance belongs to a preset untrustworthy flow resistance condition. If not, proceed to step S2. If so, proceed to step S3. The untrustworthy flow resistance condition is a transient condition with a short duration.

[0036] S2. Filter the current flow resistance, and determine the current carbon load of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table.

[0037] S3. Determine the current carbon load of the DPF based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table.

[0038] This embodiment accurately calculates and effectively manages the DPF carbon load by determining whether the vehicle operating condition corresponding to the current DPF flow resistance falls within a preset untrustworthy flow resistance condition. If the vehicle operating condition does not fall within the untrustworthy flow resistance condition, the current flow resistance is filtered and combined with a pre-calibrated flow resistance-carbon load relationship table to determine the current DPF carbon load. If the vehicle operating condition falls within the untrustworthy flow resistance condition, the current DPF carbon load is determined directly based on the previously filtered flow resistance value and the pre-calibrated flow resistance-carbon load relationship table, as the untrustworthy flow resistance condition is a transient condition with a limited impact on the DPF carbon load.

[0039] Furthermore, in one embodiment, the unreliable flow resistance conditions in step S1 include, but are not limited to, low-load conditions, rapidly increasing DPF differential pressure conditions, overrun conditions, low-temperature conditions, engine regeneration conditions, and fault conditions. In this application, any condition that can cause significant fluctuations in DPF carbon load-related calculation parameters (such as differential pressure and exhaust volume flow rate) is considered an unreliable flow resistance condition. The DPF carbon load calculated based on the measured parameters during an unreliable flow resistance condition may fluctuate beyond the normal range of the DPF carbon load, resulting in reduced accuracy. Because unreliable flow resistance conditions are transient and short-lived, their impact on the DPF carbon load is limited, and the actual DPF carbon load remains within a normal range. Therefore, the current carbon load can be determined directly based on the previously filtered flow resistance value, combined with a pre-calibrated flow resistance-carbon load relationship table. This results in a closer approximation to the actual carbon load than the DPF carbon load calculated based on the measured parameters during an unreliable flow resistance condition, improving accuracy.

[0040] Furthermore, in one embodiment, before determining in step S1 whether the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to a preset untrustworthy flow resistance condition, the following steps may be further included: The current flow resistance of the DPF is calculated based on the currently measured carbon-free load differential pressure, carbon-containing load differential pressure, and exhaust volume flow rate of the DPF.

[0041] Furthermore, in one embodiment, when determining the low-load condition, a small exhaust volume flow rate range is first preset, and then the determination is performed through the following steps: Obtain the current DPF exhaust volume flow rate and determine whether the current DPF exhaust volume flow rate is within a preset small exhaust volume flow rate range. If so, the vehicle is in a low-load condition; otherwise, the vehicle is not in a low-load condition.

[0042] The low-load operating condition of this embodiment takes into account the fluctuation of the exhaust volume flow of the DPF, which causes the carbon load of the DPF to exceed the normal range.

[0043] Furthermore, in one embodiment, when determining the above-mentioned DPF pressure differential rapidly increasing operating condition, an upper limit of the carbon loading pressure differential change rate is first preset, and then the determination is performed through the following steps: Obtain the carbon load pressure difference of the DPF at the current moment and the carbon load pressure difference of the DPF at the previous moment, calculate the current carbon load pressure difference change rate of the DPF, and determine whether the current carbon load pressure difference change rate of the DPF is greater than the preset upper limit of the carbon load pressure difference change rate. If so, the vehicle is in a condition where the DPF pressure difference increases rapidly; if not, the vehicle is not in a condition where the DPF pressure difference increases rapidly.

[0044] The DPF pressure difference rapidly increasing working condition of this embodiment takes into account the fluctuation of the DPF pressure difference, which causes the carbon load of the DPF to exceed the normal range.

[0045] Furthermore, in one embodiment, when determining the low temperature operating condition, a temperature threshold and a time threshold are first preset, and then the determination is performed through the following steps: Obtain the current DPF exhaust temperature and determine whether the current DPF exhaust temperature is greater than a preset temperature threshold. If not, the vehicle is in a low-temperature operating condition. If so, determine whether the duration for which the current DPF exhaust temperature is greater than the preset temperature threshold is less than a preset time threshold. If so, the vehicle is in a low-temperature operating condition. If not, the vehicle is not in a low-temperature operating condition.

[0046] The low temperature operating condition of this embodiment takes into account the fluctuation of the DPF pressure difference, which causes the carbon load of the DPF to exceed the normal range.

[0047] Furthermore, in one embodiment, the above-mentioned fault conditions include: air flow meter measurement deviation, air flow meter open circuit or short circuit, differential pressure sensor open circuit or short circuit, and unreasonable differential pressure sensor measurement value.

[0048] In this embodiment, the air flow meter measurement deviation, the air flow meter open circuit or short circuit takes into account the fluctuation of the exhaust volume flow of the DPF, causing the carbon load of the DPF to exceed the normal range; the pressure difference sensor open circuit or short circuit, and the unreasonable pressure difference sensor measurement value take into account the fluctuation of the pressure difference of the DPF, causing the carbon load of the DPF to exceed the normal range.

[0049] Furthermore, in one embodiment, the above-mentioned OverRun operating condition and engine regeneration operating condition are directly identified by the vehicle's electronic control unit.

[0050] In this embodiment, the OverRun operating condition and the engine regeneration operating condition take into account the fluctuation of the exhaust volume flow rate of the DPF, which causes the carbon load of the DPF to exceed the normal range.

[0051] Furthermore, in one embodiment, in the above step S3, the pre-calibrated flow resistance-carbon loading relationship table is calibrated under different driving conditions of the vehicle.

[0052] Furthermore, in one embodiment, the DPF carbon load determination method proposed in the application can adjust the DPF carbon load determination logic by using the bit method of the ECU (Electronic Control Unit) to identify the operating state quantity.

[0053] First, different bits are assigned to different working conditions. Specifically, bit 1 corresponds to low-load conditions, bit 2 corresponds to DPF pressure differential rapid increase conditions, bit 3 corresponds to OverRun conditions, bit 4 corresponds to low-temperature conditions, bit 5 corresponds to engine regeneration conditions, and bit 6 corresponds to fault conditions.

[0054] When the bit is 0, the current flow resistance is filtered by the PT (Proportional-Integral) filter, and the current carbon load of the DPF is determined based on the filtered flow resistance and the pre-calibrated flow resistance-carbon load relationship table. When the bit is 1, the PT filter is frozen, and the current carbon load of the DPF is determined based on the last filtered flow resistance and the pre-calibrated flow resistance-carbon load relationship table.

[0055] The setting logic of the bits in different working conditions is as follows: (1) Low load conditions The ECU collects the exhaust volume flow V of the DPF through the flow sensor and sets the minimum exhaust volume flow range V0. When V is within V0, bit1 is set to 1, otherwise bit1 is set to 0.

[0056] (2) DPF pressure differential increases rapidly The ECU collects the carbon load differential pressure of the DPF at the current moment and the carbon load differential pressure of the DPF at the previous moment from the pressure differential sensor, filters them, and calculates the real-time pressure differential change rate Dp; a carbon load pressure differential change rate upper limit Dp is preset. max , when Dp>Dp max When bit 2 is set to 1, otherwise bit 2 is set to 0.

[0057] (3) OverRun condition The ECU determines whether it is in the OverRun condition through the engine injection signal and the vehicle speed signal. If it is in the OverRun condition, bit3 is set to 1, otherwise bit3 is set to 0.

[0058] (4) Low temperature conditions The ECU collects the exhaust temperature of the DPF through the DPF inlet temperature sensor and presets a temperature threshold and a time threshold. The temperature threshold is greater than 100°C and can be set to 120°C.

[0059] When the exhaust temperature of the DPF is lower than the temperature threshold, or the duration of the exhaust temperature of the DPF being greater than or equal to the temperature threshold is less than the time threshold, bit 4 is set to 1; otherwise, bit 4 is set to 0.

[0060] (5) Engine regeneration condition The ECU uses the regeneration control logic to determine whether it is in the engine regeneration condition. If it is in the engine regeneration condition, bit 5 is set to 1, otherwise bit 5 is set to 0.

[0061] (6) Fault conditions The ECU monitors the fault signals of the fault cluster in real time, including air flow meter measurement deviation, air flow meter open circuit or short circuit, differential pressure sensor open circuit or short circuit, and unreasonable differential pressure sensor measurement value.

[0062] When at least one fault is triggered, the corresponding bit of the fault status quantity Er_st is set to 1, thereby triggering bit6 to be set to 1; otherwise, the corresponding bit of Er_st is set to 0, thereby triggering bit6 to be set to 0.

[0063] This embodiment incorporates bits for multiple operating conditions and the fault status variable Er_st, combining computer programs with hardware modules (such as the ECU and sensors) to determine DPF carbon loading. Specifically, the six bits of NstRaw correspond to six operating conditions. Through logical analysis, the flow resistance filtering calculation is dynamically shielded, preventing inaccurate DPF carbon loading calculations due to abnormal operating conditions.

[0064] In the second aspect, based on the above-mentioned embodiment of the method for determining the carbon load of a DPF, the present application provides an embodiment of a system for determining the carbon load of a DPF. Figure 2 As shown, the above system includes a judgment module, a filtering module, and a carbon loading module. Specifically: The judgment module judges whether the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to a preset flow resistance untrustworthy operating condition.

[0065] The filtering module is used to filter the current flow resistance when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not belong to the preset flow resistance untrustworthy operating condition.

[0066] A carbon load module is used to determine the current carbon load of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not belong to the preset flow resistance untrustworthy operating condition. It is also used to determine the current carbon load of the DPF based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to the preset flow resistance untrustworthy operating condition.

[0067] Since the unreliable flow resistance condition is a transient condition with an extremely short duration, it will not cause abnormal fluctuations in the actual carbon load, that is, under this condition, the actual carbon load remains within the normal range. However, this condition will affect the measurement results of the DPF pressure difference and exhaust volume flow, thereby affecting the calculation accuracy of the flow resistance, and ultimately leading to inaccurate carbon load calculation results. In the present application, when the vehicle operating condition belongs to the preset unreliable flow resistance condition, the flow resistance under this condition is not used to determine the carbon load. Instead, the flow resistance value after the last filtering is directly used, combined with the pre-calibrated flow resistance and carbon load relationship table to determine the current carbon load. This method effectively avoids the flow resistance calculation error caused by inaccurate measurement of the DPF pressure difference and exhaust volume flow, thereby improving the accuracy of the carbon load calculation.

[0068] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0069] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0070] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0071] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0072] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0073] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0074] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for determining DPF carbon load, characterized in that: The method comprises: Determine whether the vehicle operating condition corresponding to the current DPF flow resistance belongs to the preset untrustworthy flow resistance condition: If not, filtering the current flow resistance, and determining the current carbon load of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table; If yes, the current flow resistance is not filtered, and the current carbon load of the DPF is determined based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table; The unreliable flow resistance operating condition is a transient operating condition.

2. The method for determining DPF carbon load according to claim 1, wherein: The unreliable flow resistance operating conditions include low load conditions, DPF pressure difference rapidly increasing conditions, OverRun conditions, low temperature conditions, engine regeneration conditions, and fault conditions.

3. The method for determining DPF carbon load according to claim 1, wherein: Before determining whether the vehicle operating condition corresponding to the current DPF flow resistance belongs to the preset untrustworthy flow resistance operating condition, the following steps are also included: The current flow resistance of the DPF is calculated based on the currently measured carbon-free load differential pressure, carbon-containing load differential pressure, and exhaust volume flow rate of the DPF.

4. The method for determining DPF carbon load according to claim 2, wherein: The low load condition is determined as follows: When the exhaust volume flow rate of the DPF is within a preset small exhaust volume flow rate range, the vehicle is in a low-load operating condition.

5. The method for determining DPF carbon load according to claim 2, wherein: The method for determining the DPF pressure difference rapidly increasing condition is as follows: When the rate of change of the carbon load pressure difference of the DPF is greater than a preset upper limit of the rate of change, the vehicle is in a condition where the DPF pressure difference increases rapidly.

6. The method for determining DPF carbon load according to claim 2, wherein: The judgment method of the low temperature working condition is: When the exhaust temperature of the DPF is lower than a preset temperature threshold, or the duration of the exhaust temperature of the DPF being greater than or equal to the preset temperature threshold is shorter than a preset time threshold, the vehicle is in a low-temperature operating condition.

7. The method for determining DPF carbon load according to claim 2, wherein: The fault conditions include: air flow meter measurement deviation, air flow meter open circuit or short circuit, differential pressure sensor open circuit or short circuit, and unreasonable differential pressure sensor measurement value.

8. The method for determining DPF carbon load according to claim 2, wherein: The OverRun operating condition and the engine regeneration operating condition are directly identified by the vehicle's electronic control unit.

9. The method for determining DPF carbon load according to claim 1, wherein: The pre-calibrated flow resistance-carbon load relationship table is calibrated under different driving conditions of the vehicle.

10. A determination system based on the DPF carbon load determination method according to any one of claims 1 to 9, characterized in that: The system comprises: A judgment module determines whether the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to a preset untrustworthy flow resistance condition; a filtering module configured to filter the current flow resistance when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not fall under a preset untrustworthy flow resistance condition; A carbon load module is used to determine the current carbon load of the DPF based on the filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF does not belong to the preset flow resistance untrustworthy operating condition. It is also used to determine the current carbon load of the DPF based on the last filtered flow resistance and a pre-calibrated flow resistance-carbon load relationship table when the judgment module determines that the vehicle operating condition corresponding to the current flow resistance of the DPF belongs to the preset flow resistance untrustworthy operating condition.

Images