CN110410186B

CN110410186B - Method and system for detecting amount of particulate matter, storage medium, and control unit

Info

Publication number: CN110410186B
Application number: CN201810383136.3A
Authority: CN
Inventors: 秦岩; 田威; 林伟青; 肖云存
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2022-12-02
Anticipated expiration: 2038-04-26
Also published as: CN110410186A

Abstract

The invention discloses a method for detecting an amount of particulates trapped by a diesel particulate filter (31) of a diesel engine, the method comprising at least the steps of: detecting whether the diesel particulate filter (31) is in a deteriorated condition; and introducing a correction parameter (c) to calculate the amount of particulates if it is detected that the diesel particulate filter (31) is in a degraded condition, and not introducing the correction parameter (c) to calculate the amount of particulates otherwise. The invention also discloses a corresponding system, a computer readable storage medium and a control unit. By introducing the correction parameters when the diesel particulate filter is in a deterioration condition, the calculation accuracy can be improved or the calculated amount of the soot particles is slightly larger than the actual amount of the soot particles, so that a regeneration instruction can be accurately provided and corresponding regulation requirements can be met.

Description

Method and system for detecting amount of particles, storage medium and control unit

Technical Field

The invention relates to a method for detecting an amount of particulate matter trapped by a diesel particulate filter of a diesel engine, a corresponding system, a computer-readable storage medium and a control unit for a vehicle.

Background

Diesel engines have been widely used in some fields due to their advantages of large torque, good economic performance, etc. However, in the case of diesel engines, exhaust gas containing many harmful components such as particulate matter, nitrogen oxides, and the like is generated during operation. The particulate matter is primarily carbon, commonly referred to as soot, which not only becomes airborne as smoke, but more importantly, the fine particles can penetrate deep into the human lungs causing damage to the lungs. These particulates also tend to have adsorbed thereon a number of organic materials, such as polycyclic aromatics, that have varying degrees of mutagenic and carcinogenic effects.

Therefore, current diesel engines are generally equipped with diesel particulate filters to meet increasingly stringent environmental requirements. Diesel particulate filters are commonly installed in the exhaust system of diesel engines to reduce harmful particulates in the exhaust gas.

The diesel particulate filter mainly comprises a particulate filtering system and a regeneration system. The particulate matter filtering system may cause problems such as an increase in exhaust back pressure with an increase in the amount of particulate matter captured, which in turn may affect the dynamic and economical efficiency of the engine. Therefore, it is desirable to detect the amount of soot trapped in a diesel particulate filter and activate a regeneration system, such as to remove particulates by high temperature combustion, to restore the performance of the diesel particulate filter when the amount of soot in the diesel particulate filter reaches a predetermined threshold.

At present, the amount of soot particles is usually calculated indirectly by a model. However, for a soot detection model, which is highly dependent on the raw emissions of the engine, failure of some components, such as oil leakage, etc., may render the model less accurate. For differential pressure based calculation methods, which are mainly for commercial vehicles, the differential pressure is usually low, in which case the error of the differential pressure sensor and the tolerances of the mass production of the carrier plus the influence of passive regeneration may make it impossible to accurately detect the amount of soot particles. For this reason, it is urgently required to improve the existing detection method of the amount of soot particles so that the diesel particulate filter can always operate efficiently.

Disclosure of Invention

It is an object of the present invention to provide an improved method for detecting an amount of particulates trapped by a diesel particulate filter of a diesel engine, a corresponding system, a computer readable storage medium and a control unit for a vehicle, to improve the reliability of the detection model and to prevent overheating damage of the diesel particulate filter.

According to a first aspect of the present invention, a method for detecting an amount of particulate matter trapped by a diesel particulate filter of a diesel engine is provided, the method comprising at least the steps of: detecting whether the diesel particulate filter is in a deterioration condition; and if the diesel particulate filter is detected to be in a deterioration condition, introducing a correction parameter to calculate the particulate matter amount, otherwise, not introducing the correction parameter to calculate the particulate matter amount.

According to a second aspect of the present invention, there is provided a system for detecting an amount of particulate matter trapped by a diesel particulate filter of a diesel engine, the system comprising: a control unit configured to: and detecting whether the diesel particulate filter is in a deterioration working condition, introducing a correction parameter to calculate the particulate matter amount if the diesel particulate filter is detected to be in the deterioration working condition, and not introducing the correction parameter to calculate the particulate matter amount if the diesel particulate filter is not detected to be in the deterioration working condition.

According to a third aspect of the present invention, there is provided a computer readable storage medium having stored thereon program instructions, wherein the program instructions, when executed by a processor, implement the steps of the method.

According to a fourth aspect of the present invention there is provided a control unit for a vehicle, the control unit comprising a memory, a processor and program instructions stored on the memory and operable on the processor, wherein the processor implements the steps of the method when executing the program instructions.

By introducing the correction parameters when the diesel particulate filter is in a deterioration condition, the calculation accuracy can be improved or the calculated amount of the soot particles is slightly larger than the actual amount of the soot particles, so that a regeneration instruction can be accurately provided and corresponding regulation requirements can be met.

Drawings

The principles, features and advantages of the present invention may be better understood by describing the invention in more detail below with reference to the accompanying drawings. The drawings comprise:

fig. 1 schematically shows a block schematic diagram of an engine and an exhaust emission treatment system.

Figure 2 shows a schematic of a prior art model.

Fig. 3 shows two different linear relationships between the exhaust pressure difference and the third power of the volume flow.

Fig. 4 shows the change over time of the proportionality factor between the exhaust pressure difference and the third power of the volume flow.

Fig. 5 shows a model for calculating the amount of soot particles with the introduction of correction parameters according to an exemplary embodiment of the present invention.

FIG. 6 shows a model diagram of a calculation of soot particle amount incorporating a correction parameter according to another exemplary embodiment of the present invention.

FIG. 7 shows a schematic diagram of a model of how a correction may be made when determining that a diesel particulate filter is in a degraded condition, according to another exemplary embodiment of the present invention.

Fig. 8 shows a flow chart of a method for determining an amount of soot particles according to an exemplary embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous technical effects of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and exemplary embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of the invention.

Fig. 1 schematically shows a block schematic diagram of an engine and an exhaust emission treatment system. After the diesel engine 10 of the diesel vehicle is started, exhaust gas is conducted to the exhaust emission treatment system 30 through the exhaust pipe 20. The exhaust emission treatment system 30 includes a diesel particulate filter 31 for filtering particulate matter in the exhaust gas. The filtered exhaust gas is then exhausted outside the diesel vehicle via an exhaust pipe 20 passing through an exhaust emission treatment system 30.

Currently, there are several methods of determining the amount of soot particles of the diesel particulate filter 31 according to different situations, for example, for different vehicle models.

For example, a first way is to provide

pressure sensors

32 and 33 at both the inlet and outlet ends of the diesel particulate filter 31, respectively, for detecting the exhaust pressure at the inlet and outlet. A control unit 40, for example, an ECU (electronic control unit) of a diesel vehicle obtains pressure detection values from these two

pressure sensors

32 and 33, and calculates the amount of soot that has been trapped in the diesel particulate filter 31 by back-stepping on the basis of the exhaust pressure difference Δ p between the inlet and the outlet. Of course, it is also possible to provide a differential pressure sensor which directly measures the pressure difference Δ p between the inlet and the outlet of the diesel particulate filter 31. As the amount of trapped soot increases, the exhaust gas no longer flows easily through the dpf 31, i.e., the flow resistance of the dpf 31 is greater at this time, and the pressure difference Δ p between the inlet and the outlet increases accordingly. In this case, the model is relatively simple, and the input parameter is mainly differential pressure.

Of course, the model can also incorporate other input parameters, for example, the volume flow q of the exhaust gas, the vehicle speed v, etc. Fig. 2 shows a schematic diagram of such a model, and the model f (Δ p, q, v) calculates the soot amount Sw1 from the input signals. The method is particularly suitable for light-duty diesel vehicles.

The control unit 40 may control the diesel engine 10 and the exhaust emission treatment system 30 separately. For example, the control unit 40 may command the exhaust emission treatment system 30 to instruct the diesel particulate filter 31 to perform a regeneration process, as needed.

The second mode is as follows: the operating parameters of the diesel vehicle, such as the mileage (between the two regeneration process starts), the operating time of the diesel engine, and the integrated fuel consumption value, which are allowed when the regeneration of the dpf 31 is performed, are calculated in advance based on the exhaust emission standard, and then a predetermined value is defined based on the operating parameters calculated in advance, and the dpf 31 is directly instructed to perform the regeneration by the control unit 40 whenever the predetermined value is reached. In this case, the input parameters of the model mainly include the driving mileage, the operating time of the diesel engine, and the fuel consumption integrated value. As the mileage increases, the total amount of exhaust gas emitted from the automobile increases, and therefore, the amount of soot trapped in the diesel particulate filter 31 also increases. Similarly, the amount of soot trapped by the diesel particulate filter 31 also increases as the operating time and the cumulative value of fuel consumption of the diesel engine increase. Of course, other input parameters may be introduced.

The third mode is that: the method is characterized in that the soot particle amount collected by a diesel particulate filter under different working condition parameters (such as different engine rotating speeds, oil consumption per unit time, air intake flow and the like) is tested under a test state aiming at a standard diesel vehicle type (or a vehicle type used for a record test), and then the soot particle amount is stored and recorded as a reference parameter table. Thereafter, for another diesel vehicle of the same model, after each regeneration process is completed (i.e., before the next regeneration is started) based on the stored reference parameter table, the control unit estimates the amount of soot trapped in the diesel particulate filter based on the actual operating parameters of the diesel vehicle (e.g., the engine speed, the fuel consumption per unit time, etc.), and after the amount of soot is accumulated to a certain value, the control unit directly instructs the diesel particulate filter 31 to perform regeneration. In this case, the input parameters of the model include the various operating condition parameters described above. The model utilizes table look-up comparison and accumulation calculation. This is particularly suitable for heavy duty diesel vehicles.

In practice, the model for determining the initiation of regeneration is not limited to the above three modes, and they may be combined with each other or modified with each other, and the present invention does not set any limit to the type of the model. In other words, as long as the model can estimate the soot particle amount based on the input parameters, various estimation methods are described in, for example, CN102628386A and the like.

However, in any of the current models, it is found that the detection is inaccurate, and the early and frequent regeneration may be caused, and the late regeneration may be caused. Too early, too frequent regeneration can cause energy waste, reduces the life of diesel particulate filter, worsens the dilution of machine oil, and too late regeneration can make combustion temperature too high again and make diesel particulate filter produce the danger of burning apart, and the waste gas of emission also can not satisfy the environmental protection requirement, also can reduce diesel engine's working property. Clearly, the risk and danger of too late regeneration is greater relative to too early regeneration, and therefore it is highly desirable to be able to accurately estimate or suitably overestimate the amount of soot particles so that active regeneration can be triggered in time or slightly earlier.

Too late regeneration means that the actual amount of trapped soot is larger than that calculated by the model, usually because the deteriorating conditions of the diesel particulate filter 31 are not taken into account. In particular, the occurrence of certain abnormal or extreme conditions, such as the air system and/or the fuel system of the engine or the diesel particulate filter 31 itself, may cause the diesel particulate filter 31 to be in a fast-loading state, which if not discovered and considered in time, may cause the actual amount of soot to be greater than that calculated by the model, resulting in too late regeneration.

For this reason, it is first necessary to reliably detect the deterioration condition of the diesel particulate filter 31, at least the deterioration condition of the diesel particulate filter 31 cannot be missed. There are various factors that put the diesel particulate filter 31 into a deteriorated condition, and it is described below only by way of example which information can be used to judge that the diesel particulate filter 31 is in a deteriorated condition.

1) First exemplary judging method

The following functional relationship exists between the exhaust pressure difference Δ p and the volume flow q:

Δp＝k*q ³ (1)

wherein k is a proportionality coefficient.

Obviously, the pressure difference Δ p is linear with the third power of the volume flow q, and the larger the amount of soot particles trapped by the diesel particulate filter 31 is, the larger the proportionality coefficient k is, the larger the pressure difference Δ p is.

The functional relationship is shown in fig. 3 for two different cases. The linear relationship y1 represents the case where the diesel particulate filter is new and unused, and the proportionality coefficient k1 is small, and the linear relationship y2 represents the case where the diesel particulate filter is fully loaded, and the proportionality coefficient k2 is larger than k1.

k1 may be determined when the vehicle is first used and then stored in a corresponding memory. K1 can also be determined by measuring the volume flow q of exhaust gas and the pressure difference Δ p at this time if a new diesel particulate filter is replaced or if all trapped substances in the diesel particulate filter are completely removed. If necessary, k1 can also be calibrated by testing. To be more accurate, even with a new diesel particulate filter, regeneration is initiated before each determination of k1 to eliminate any possible soot.

The pressure differential Δ p required to trigger regeneration upon determining that the diesel particulate filter is fully loaded may be predetermined. The scaling factor k2 can be determined by the volumetric flow q of the exhaust gas on the basis of the predetermined differential pressure Δ p.

In order to ensure the accuracy of the determination of the value k, according to an exemplary embodiment of the present invention, a volume flow interval may be selected, and the calculation of the scaling factor k is only performed if the measured volume flow q is within the volume flow interval, as indicated by the shaded box 1 in fig. 3.

According to another exemplary embodiment of the present invention, in order to ensure the accuracy of the k value determination, it is possible to calculate an average value of k values within a predetermined period of time as the k value that is currently required to be taken. It will be apparent to those skilled in the art that other processing methods, such as other low-pass filtering techniques, may be used to obtain a more reliable k value.

The diesel particulate filter is gradually accumulating soot particulates under normal operating conditions, which is shown by the fact that the proportionality coefficient k is approximately linearly changing with the operating time t of the engine in the interval between k1 and k2, as shown by the dashed line 2 in fig. 4.

According to an exemplary embodiment of the present invention, a variable r is defined to reflect how fast the k value changes, as shown in equation (2):

where Δ k represents the amount of change in k value within Δ t time. When the k value changes so drastically that r is greater than a predetermined threshold value r1, the diesel particulate filter is considered to be in a rapidly loaded state, i.e., a deteriorated condition.

According to an exemplary embodiment of the present invention, an average value of r values over a period of time may also be calculated as the r value to be determined to reduce false positives.

As shown in fig. 4, the solid line 3 has a larger slope than the dashed line 2, indicating that the k value is changed drastically at this time, and thus the diesel particulate filter can be considered to be in a deteriorated condition.

2) Second exemplary judging method

An air system of a diesel engine generally includes an exhaust gas recirculation system coupled between an exhaust pipe and an intake pipe and including, for example, an exhaust gas recirculation valve, an exhaust gas recirculation cooler, and the like, and a turbocharger system coupled to the exhaust pipe to increase an intake pressure of the diesel engine using exhaust gas in the exhaust pipe and including, for example, a supercharger shaft, an air compressor, and the like. Both the exhaust gas recirculation system and the turbocharging system receive exhaust gas from the exhaust pipe, and their intake air flows are controlled by an exhaust gas recirculation valve and a supercharging valve, respectively. In operation, a control unit, such as control unit 40 shown in FIG. 1, generates corresponding EGR valve drive signals and boost valve drive signals based on engine operating conditions for controlling the opening of the EGR valve and boost valve, respectively.

When the air system is operating abnormally, for example, in a malfunction, the air entering the cylinders of the engine may no longer be able to efficiently burn the diesel fuel injected into the cylinders, thereby affecting the exhaust gas composition. For this purpose, for example, the control unit 40 detects the air system during operation and, if an abnormal situation occurs, generates an air system error signal, which may also mean that the diesel particulate filter is in a degraded condition.

3) Third exemplary judging method

The air-fuel ratio α, which represents the mixture ratio of air and diesel, is a very important parameter when the engine is operating, and has a great influence on exhaust emissions, the power performance and the economy of the engine. The mixed gas with the air-fuel ratio alpha larger than the theoretical air-fuel ratio alpha 1 is called lean mixed gas, the gas is rich in oil and less in oil, the combustion is complete, the oil consumption is low, the pollution is low, and the power is low. The air-fuel mixture with the air-fuel ratio alpha smaller than the theoretical air-fuel ratio alpha 1 is called rich air-fuel mixture, and the air-fuel mixture has less oil and more power, but the combustion is incomplete, the oil consumption is high, the pollution is large, and the exhaust condition is deteriorated. For this reason, an air-fuel ratio threshold value α 2 may be set, and it may be determined that the diesel particulate filter is in a deteriorated condition when the actual air-fuel ratio α is lower than the air-fuel ratio threshold value α 2.

When the fuel injection system of the engine is abnormal, the fuel injection quantity can be influenced, and the air-fuel ratio alpha is changed, so that the condition of the fuel injection system can be reflected to a certain extent through the change of the air-fuel ratio alpha.

According to an exemplary embodiment of the present invention, in order to avoid erroneous determination, it is possible to calculate the average value of the air-fuel ratio α in a predetermined period as the value of α that is currently required to take.

In practice, it may be determined whether the diesel particulate filter is in a deteriorated condition based on other parameters (i.e., modified parameters based on the air-fuel ratio) that have the air-fuel ratio α as a function variable, for example, the ratio λ of the actual air-fuel ratio to the stoichiometric air-fuel ratio, which is also actually determined based on the air-fuel ratio.

It is described above that the diesel particulate filter may be judged to be in the deteriorated condition based on the increase of the proportionality coefficient k, the generation of the error signal with respect to the air system, or the decrease of the air-fuel ratio α, but these are merely exemplary and not restrictive to those skilled in the art, and for example, any combination therebetween may be used for the judgment. There are many parameters and factors that affect the composition of the exhaust gas, as long as it can be determined that more particulate matter needs to be filtered in the exhaust gas, so that the diesel particulate filter is in a degraded condition.

According to the present invention, when it is determined that the diesel particulate filter is in a degraded condition, the soot model needs to be corrected so that the soot model more accurately calculates the amount of soot trapped by the diesel particulate filter and/or allows a suitably excessive estimation of the amount of soot, since it is not optimal to trigger the active regeneration properly too early, but it is ensured that overheating of the diesel particulate filter is avoided.

To more clearly and more generally describe how the model is modified, a general functional relationship is defined as follows:

Sw＝f(c,x) (3)

where Sw denotes the soot amount, f denotes a functional relationship, c denotes a correction parameter, and x denotes other input parameters, such as the pressure difference Δ p, the volume flow q, the vehicle speed v, and the like. It is noted that the number of correction parameters and other parameters is not limited.

According to a preferred exemplary embodiment of the present invention, the above formula (3) may be modified as follows:

Sw＝f(c，Sw1) (4)

wherein Sw1 represents the calculated amount of soot particles without considering the deterioration condition of the diesel particulate filter as described above, which can be calculated by the existing model, and then Sw1 is corrected by introducing the correction parameter c.

Calculating the soot amount according to the formula (4) can simplify the calculation and reduce the amount of calculation because the calculation result of the existing model can be corrected without changing the existing model. By this method, existing models can be easily modified without reprogramming, and the reliability of the system is improved.

According to another preferred exemplary embodiment of the present invention, the soot amount Sw is calculated based on the soot amount Sw1 using the following formula (5):

Sw＝f(c)*Sw1 (5)

where f (c) represents a correction function based on the correction parameter c, which can further simplify the calculation of the soot amount Sw.

Fig. 5 shows a model for calculating the amount of soot particles with the introduction of a correction parameter c according to an exemplary embodiment of the present invention. As shown in fig. 5, a submodel, i.e., a function f (c), may be constructed to calculate a correction factor β, which is then input to the model f (Δ p, q, v, β) along with the pressure difference Δ p, the volume flow q, and the vehicle speed v to calculate the amount of soot.

Fig. 6 shows a model for calculating the amount of soot particles with the introduction of a correction parameter c according to another exemplary embodiment of the present invention. As shown in fig. 6, the flow rate signal q is introduced into a sub-model to be modified by the modification parameter c to generate a modified flow rate signal q' and then input into the model f (Δ p, q, v), so that the number and kind of input parameters of the existing model may not be changed, and further, the existing model does not need to be modified.

FIG. 7 shows a schematic diagram of a model of how a correction may be made when it is determined that a diesel particulate filter is in a degraded condition, according to another exemplary embodiment of the present invention.

As shown in fig. 7, the model includes a conventional model portion including a soot static emission map i and a soot dynamic emission map iii, and a correction portion including a soot static emission map correction curve ii and a soot dynamic emission correction map iv. The soot static emission mapping I and the soot static emission mapping correction curve II are connected to the first change-over switch 4, and the soot dynamic emission mapping III and the soot dynamic emission correction mapping IV are connected to the second change-over switch 5. The input parameters of the soot static emission mapping I are engine speed n and fuel injection quantity b, and the input parameters of the soot static emission mapping correction curve II are variables r reflecting the change speed of the k value. The input parameters of the soot dynamic emission map III are an actual ratio lambda and a difference lambda-lambda 1 between the actual ratio lambda and a theoretical ratio lambda 1, and the input parameters of the soot dynamic emission correction map IV are the same as those of the soot dynamic emission map III. When the diesel particulate filter is in a normal working condition, the first change-over switch 4 and the second change-over switch 5 are in a first working state, as shown in fig. 7, and at the moment, the soot amount is calculated through superposition of the soot static emission map I and the soot dynamic emission map III. When the diesel particulate filter is in a deterioration condition and generates a trigger signal 6, the first change-over switch 4 and the second change-over switch 5 are switched to a second working state under the trigger of the trigger signal 6, namely, switched downwards in fig. 7, and at this time, the amount of soot is calculated through a soot static emission map correction curve II and a soot dynamic emission correction map iv, wherein the soot static emission map correction curve II firstly corrects the soot static emission map i, for example, multiplies the soot static emission map i to obtain a soot static emission correction map v, as shown by a reference numeral 7 in fig. 7, and then the soot static emission correction map v and the soot dynamic emission correction map iv are superposed to calculate the amount of soot.

According to an exemplary embodiment of the invention, the soot static emission map correction curve ii corrects the soot static emission map I such that the soot static emission correction map v is larger than the soot static emission map I, and/or the soot dynamic emission correction map iv is larger than the soot dynamic emission map iii at the same input parameters, for example by using a larger calibration coefficient. By means of such a correction, the actual soot quantity can be reflected more accurately or the calculated soot quantity can be made slightly larger than the actual soot quantity, so that the active regeneration can be triggered in a timely manner or slightly earlier.

In practice, the influence of the correction parameter c on the soot particle amount can be determined by experiments or simulations and then, for example, a correction function f (c) is constructed on the basis of the influence and stored in a memory of the control unit 40 or in a separate memory. When the amount of soot particles needs to be calculated, the obtained correction parameter c is considered to participate in the calculation of the amount of soot particles through the correction function f (c), so that the calculation accuracy of the amount of soot particles can be improved and/or the calculated amount of soot particles is ensured not to be obviously smaller than the actual amount of soot particles. For example, corresponding experiments or simulations may be performed to determine the correction function for different models of vehicles, respectively. For the cumulative calculation of the soot particle quantity, the influence of the correction variable c is taken into account at each calculation.

According to an exemplary embodiment of the present invention, the correction function f (c) may be stored in a look-up table, which may reduce the amount of calculation.

The method starts with step S1. In step S2, it is determined whether the diesel particulate filter is in a degraded condition. If yes, the process proceeds to step S3, and the soot amount is calculated with the correction parameter c introduced. If not (N), proceed to step S4, calculate the amount of soot without introducing the correction parameter c, e.g., using a conventional model. In step S5, the soot particle amount Sw is obtained.

When the amount Sw of soot particles is determined, it is compared with a set threshold value to determine whether a regeneration command needs to be issued.

Through a large number of experiments, the correction parameters are introduced when the diesel particulate filter is in a deterioration working condition, so that the calculation accuracy can be improved or the calculated amount of the soot particles is slightly larger than the actual amount of the soot particles, and a regeneration instruction can be accurately provided and the corresponding regulation requirements can be met.

Further, although the present invention has been described above by taking a diesel vehicle as an example, the idea of the present invention is applicable to any apparatus using a diesel engine.

Although specific embodiments of the invention have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications may be devised without departing from the spirit and scope of the present invention.

Claims

1. A method for detecting an amount of particulates trapped by a diesel particulate filter (31) of a diesel engine, the method comprising at least the steps of:

detecting whether the diesel particulate filter (31) is in a deteriorated condition; and

introducing a correction parameter (c) to calculate the amount of particulates if the diesel particulate filter (31) is detected to be in a degraded condition, otherwise not introducing the correction parameter (c) to calculate the amount of particulates;

wherein the content of the first and second substances,

defining a proportionality coefficient k by the following formula (1):

wherein Δ p represents a pressure difference between an inlet and an outlet of the diesel particulate filter (31), q represents a volume flow rate of the exhaust gas, and a variation speed of the proportionality coefficient k is reflected by defining a variable r by the following equation (2):

wherein, delta k represents the variation of the proportionality coefficient k within delta t time, if the variable is larger than a first preset threshold value, the diesel particulate filter (31) is judged to be under a deterioration working condition; and/or

-determining that the diesel particulate filter (31) is in a degraded condition based on the generation of an error signal of an air system of the diesel engine; and/or

-determining whether the diesel particulate filter (31) is in a deteriorating condition by comparing the air-fuel ratio or a variation parameter based on the air-fuel ratio with a second predetermined threshold value,

wherein the correction parameter includes at least one of the variable, the air-fuel ratio, and the variation parameter.

2. The method of claim 1,

the calculation of the scaling factor is only performed when the volume flow is within a predetermined volume flow interval.

3. The method of claim 1 or 2,

a correction function based on the correction parameter is constructed, and the particulate matter amount is calculated by correcting the initially estimated particulate matter amount calculated when the correction parameter is not introduced based on the correction function.

4. The method of claim 1 or 2,

the amount of the particulates is calculated by constructing a model, wherein the model comprises a basic model part and a correction part, the basic model part comprises a soot static emission map and a soot dynamic emission map, the correction part comprises a soot static emission correction map and a soot dynamic emission correction map, the correction parameters are input parameters of the soot static emission correction map and/or the soot dynamic emission correction map, if the diesel particulate filter (31) is detected to be in a deterioration condition, the amount of the particulates is calculated based on the soot static emission correction map and the soot dynamic emission correction map, and otherwise, the amount of the particulates is calculated based on the soot static emission correction map and the soot dynamic emission correction map.

5. The method of claim 4,

the variable is set as an input parameter of the soot static emission correction map as a first of the correction parameters, and the air-fuel ratio and/or the variation parameter is set as an input parameter of the soot dynamic emission correction map and/or the soot dynamic emission map as a second of the correction parameters.

6. The method of claim 5,

constructing a correction curve based on the variables, and generating the soot static emission correction map based on the soot static emission map and the correction curve; and/or

The variation parameters include a first variation parameter and a second variation parameter different from the first variation parameter, which are set as input parameters of the soot dynamic emission correction map and the soot dynamic emission map.

7. A system for detecting an amount of particulate matter captured by a diesel particulate filter (31) of a diesel engine, the system comprising:

a control unit (40), the control unit (40) being configured to perform the method according to any one of claims 1-6.

8. The system of claim 7,

the control unit (40) is an electronic control unit for controlling the operation of the diesel engine.

9. A computer readable storage medium having stored thereon program instructions, wherein the program instructions, when executed by a processor, implement the steps of the method of any of claims 1-6.

10. A control unit for a vehicle, the control unit comprising a memory, a processor and program instructions stored on the memory and executable on the processor, wherein the steps of the method of any of claims 1-6 are implemented when the program instructions are executed by the processor.