A DPF regeneration control method and system

Abstract

The present invention discloses a DPF regeneration control method and system, the control method comprising: obtaining the DPF pressure difference in real time, and when the DPF pressure difference is greater than a set pressure difference threshold, detecting whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hpa; if there is no pressure difference sensor fault and the pressure difference fluctuation is less than 10hpa, opening the exhaust throttle valve, otherwise determining whether the proportion of operating conditions in which the air-fuel ratio is less than 1.5 within one hour is greater than 50%; if so, also opening the exhaust throttle valve, and determining whether the pre-turbulent pressure is greater than the pre-turbulent pressure threshold, if so, performing driving regeneration, otherwise not performing driving regeneration; the present invention monitors the DPF pressure difference in real time based on a pressure difference sensor, and regenerates in time when the pressure difference exceeds the limit, thereby avoiding excessive carbon deposition causing DPF disengagement or damage. The present invention identifies the DPF carbon deposition condition based on the sensor parameters of the engine itself, without adding additional components, and can promptly identify and regenerate even when the engine fails or under special circumstances.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle exhaust after-treatment, and in particular relates to a DPF regeneration control method and system. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rise of emission regulations, diesel aftertreatment systems for China VI and non-road Stage IV diesel engines are required to incorporate a DOC (Diesel Oxidation Catalyst) and a DPF (Diesel Particle Filter) to meet limits for pollutants like PM. The DPF, located after the DOC, primarily filters PN and captures PM particles from exhaust. Existing technologies calibrate the DPF carbon deposition model based on engine smoke density and inversely calculate the DPF carbon deposition value based on the DPF differential pressure. A reliable value is used as the DPF carbon loading, triggering regeneration when the carbon loading reaches a certain threshold. However, certain factors can cause engines to produce excessive soot, leading to excessive DPF carbon deposition in a short period of time. Existing DPF control methods are only accurate when the engine is operating normally. They fail to identify and regenerate DPFs under engine faults or unusual operating conditions, potentially causing them to detach or burn out. Engine faults, such as intake manifold leaks, are not calibrated during testing, leading to inaccurate model calculations. Summary of the Invention

[0004] The purpose of the present invention is to provide a DPF regeneration control method and system, which determines whether the DPF carbon load reaches the regeneration value based on the DPF differential pressure sensor, regenerates the DPF in time, and avoids DPF damage caused by excessive carbon deposition.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a DPF regeneration control method, comprising:

[0007] Obtain DPF pressure difference in real time. When the DPF pressure difference is greater than the set pressure difference threshold, detect whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hPa;

[0008] If there is no differential pressure sensor fault and the differential pressure fluctuation is less than 10hPa, the exhaust throttle valve is opened. Otherwise, it is determined whether the proportion of operating conditions with an air-fuel ratio less than 1.5 within one hour is greater than 50%;

[0009] If so, the exhaust throttle valve is also opened, and it is determined whether the pre-turbine pressure is greater than the pre-turbine pressure threshold. If so, driving regeneration is performed, otherwise driving regeneration is not performed.

[0010] As a further technical solution, the set pressure difference threshold is obtained by calibrating the DPF pressure difference under various working conditions. When the DPF pressure difference exceeds the set pressure difference threshold under the current working condition, it means that the DPF carbon load reaches the regeneration value.

[0011] As a further technical solution, the turbine pre-pressure threshold is obtained by calibrating the turbine pre-pressure under various working conditions of the regenerated DPF carbon load.

[0012] As a further technical solution, the DPF pressure difference is obtained by a DPF pressure difference sensor.

[0013] As a further technical solution, when the DPF pressure difference is not greater than a set pressure difference threshold, driving regeneration is not performed.

[0014] As a further technical solution, the turbine pre-pressure is obtained by a turbine pre-pressure sensor.

[0015] As a further technical solution, before obtaining the pre-turbocharger pressure, it is first determined whether the pre-turbocharger pressure sensor has a fault. If there is a fault, driving regeneration is directly performed. If there is no fault, the pre-turbocharger pressure is obtained.

[0016] As a further technical solution, if the proportion of operating conditions in which the air-fuel ratio is less than 1.5 within one hour is no more than 50%, driving regeneration will not be performed.

[0017] As a further technical solution, the judgment value of the pressure difference fluctuation and the judgment value of the air-fuel ratio are both empirical values.

[0018] In a second aspect, an embodiment of the present invention provides a DPF regeneration control system, comprising:

[0019] The first judgment module is configured to: obtain the DPF pressure difference in real time, and when the DPF pressure difference is greater than a set pressure difference threshold, detect whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hPa;

[0020] The second judgment module is configured to: if there is no pressure difference sensor fault and the pressure difference fluctuation is less than 10hPa, open the exhaust throttle valve; otherwise, determine whether the proportion of operating conditions in which the air-fuel ratio is less than 1.5 within one hour is greater than 50%;

[0021] The driving regeneration trigger judgment module is configured to: if so, also open the exhaust throttle valve and judge whether the pre-turbocharger pressure is greater than the pre-turbocharger pressure threshold; if so, perform driving regeneration; otherwise, do not perform driving regeneration.

[0022] The beneficial effects of the above embodiments of the present invention are as follows:

[0023] The DPF regeneration control method provided by the present invention monitors the DPF pressure difference in real time based on a pressure difference sensor, and regenerates in time when the pressure difference exceeds the limit, thereby avoiding DPF disengagement or damage caused by excessive carbon deposition.

[0024] The present invention identifies the carbon deposit condition of the DPF according to the sensor parameters of the engine itself, without adding additional components, and can promptly identify and regenerate the engine even if it fails or under special circumstances.

[0025] The DPF regeneration control method provided by the present invention determines whether there is a fault in the pressure differential sensor and whether the detected pressure differential fluctuation is greater than the empirical value, and determines the accuracy of the pressure differential measurement twice. If the pressure differential measurement may be inaccurate, it means that the judgment cannot be made from the pressure direction. The air-fuel ratio is further judged by judging whether the air-fuel ratio is less than 1.5 in one hour. The proportion is greater than 50%, and then it is determined whether to perform driving regeneration. When it is impossible to judge whether to perform driving regeneration by pressure, the present invention proposes changing the control strategy to judge whether to perform driving regeneration by judging the air-fuel ratio, which is suitable for various special situations.

[0026] The DPF regeneration control method provided by the present invention first determines whether the pre-turbulence pressure sensor has a fault before obtaining the pre-turbulence pressure. If a fault exists, regeneration is directly performed while driving. If no fault exists, the pre-turbulence pressure is obtained. The judgment of all relevant pressures is to confirm whether the pressure difference is really high. If the pre-turbulence pressure sensor has a fault, it is directly believed that the measurement of the pressure difference sensor is correct and regeneration is directly performed. If the pre-turbulence pressure sensor has no fault, it is determined whether the pre-turbulence pressure is greater than the pre-turbulence pressure threshold. This is because if the aftertreatment is blocked, the exhaust back pressure will increase, and the pre-turbulence pressure will also rise to the threshold, then regeneration is required.

[0027] The control strategy in the prior art is only reliable in measuring the pressure difference within a certain range. The present invention uses a pressure difference sensor for full monitoring. Regardless of special working conditions or any faults, as long as the DPF pressure difference is high, it can be identified and judged in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 This is a logic diagram of the DPF regeneration control method of the present invention. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] Example 1

[0032] In a typical embodiment of the present invention, Figure 1 As shown, a DPF regeneration control method is provided, comprising:

[0033] Step 1: Obtain the DPF pressure difference in real time. When the DPF pressure difference is greater than the set pressure difference threshold, detect whether there is a pressure difference sensor failure and whether the pressure difference fluctuation is less than 10hPa.

[0034] Among them, the DPF pressure difference is obtained by a DPF pressure difference sensor, and the set pressure difference threshold is obtained by calibrating the DPF pressure difference under various working conditions. When the DPF pressure difference exceeds the set pressure difference threshold under the current working condition, it means that the DPF carbon load reaches the regeneration value. When the DPF pressure difference is not greater than the set pressure difference threshold, driving regeneration is not performed.

[0035] When the DPF pressure difference exceeds the set pressure difference threshold under the current working conditions, first determine whether there is a fault in the pressure difference. If there is a pressure difference sensor fault, it means that the obtained DPF pressure difference is inaccurate, and the driving regeneration control strategy is changed; when there is no pressure difference sensor fault, it means that the obtained DPF pressure difference is accurate, and then further determine whether the pressure difference fluctuation is less than 10hPa (10hPa is an empirical value). The accuracy of the pressure difference measurement is further determined by judging the pressure difference fluctuation. When the pressure difference fluctuation is less than 10hPa, it means that the pressure difference measurement is accurate. At this time, open the exhaust throttle valve to determine whether the actual pressure after the vortex is really over the limit; otherwise, it means that the pressure difference measurement may be inaccurate. Therefore, it cannot be judged from the pressure direction, and can only further determine the air-fuel ratio.

[0036] Step 2: If there is no pressure differential sensor fault and the pressure differential fluctuation is less than 10 hPa, open the exhaust throttle valve; otherwise, determine whether the proportion of operating conditions with an air-fuel ratio less than 1.5 within one hour is greater than 50%.

[0037] When the pressure difference fluctuation is less than 10hPa, the actual exhaust back pressure after the vortex is measured by opening the exhaust throttle valve.

[0038] In this embodiment, both the judgment value of the pressure difference fluctuation and the judgment value of the air-fuel ratio are empirical values.

[0039] The combustion condition is determined by judging whether the proportion of operating conditions with Lambd values ​​less than 1.5 within 1H is greater than 50%. If it is greater than 50%, it indicates poor combustion and regeneration is required. If the proportion of operating conditions with air-fuel ratio less than 1.5 within one hour is less than 50%, driving regeneration is not performed.

[0040] Step 3: If yes, also open the exhaust throttle valve and determine whether the pre-turbocharger pressure is greater than the pre-turbocharger pressure threshold. If yes, perform driving regeneration; otherwise, do not perform driving regeneration.

[0041] The pre-turbine pressure is obtained by a pre-turbine pressure sensor, and the pre-turbine pressure threshold is determined by calibrating the pre-turbine pressure under various operating conditions of DPF carbon loading. If the aftertreatment is clogged, exhaust backpressure will increase, and the pre-turbine pressure will also rise to the threshold, requiring regeneration.

[0042] Furthermore, before obtaining the inlet pressure, the inlet pressure sensor is first determined to be faulty. If so, regeneration is performed while the vehicle is running. If not, the inlet pressure is then obtained. All of this determination is to confirm whether the differential pressure is truly high. If the inlet pressure sensor is faulty, the differential pressure sensor's measurement is assumed to be correct, and regeneration is performed directly.

[0043] The present invention identifies DPF carbon deposits based on the engine's own sensor parameters, eliminating the need for additional components. This allows for timely identification and regeneration even in the event of an engine failure or under unusual circumstances. While existing control strategies only provide reliable differential pressure measurements within a limited range, the present invention utilizes a differential pressure sensor for full monitoring. Regardless of unusual operating conditions or any other faults, high DPF differential pressure can be promptly identified and evaluated.

[0044] Example 2

[0045] In a typical embodiment of the present invention, a DPF regeneration control system is provided, comprising:

[0046] The first judgment module is configured to: obtain the DPF pressure difference in real time, and when the DPF pressure difference is greater than a set pressure difference threshold, detect whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hPa;

[0047] The second judgment module is configured to: if there is no pressure difference sensor fault and the pressure difference fluctuation is less than 10hPa, open the exhaust throttle valve; otherwise, determine whether the proportion of operating conditions in which the air-fuel ratio is less than 1.5 within one hour is greater than 50%;

[0048] The driving regeneration trigger judgment module is configured to: if so, also open the exhaust throttle valve and judge whether the pre-turbocharger pressure is greater than the pre-turbocharger pressure threshold; if so, perform driving regeneration; otherwise, do not perform driving regeneration.

[0049] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A DPF regeneration control method, characterized in that: include: Obtain DPF pressure difference in real time. When the DPF pressure difference is greater than the set pressure difference threshold, detect whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hPa; If there is no differential pressure sensor fault and the differential pressure fluctuation is less than 10hPa, the exhaust throttle valve is opened. Otherwise, it is determined whether the proportion of operating conditions with an air-fuel ratio less than 1.5 within one hour is greater than 50%; If so, the exhaust throttle valve is also opened, and it is determined whether the pre-turbine pressure is greater than the pre-turbine pressure threshold. If so, driving regeneration is performed, otherwise driving regeneration is not performed.

2. The DPF regeneration control method according to claim 1, wherein: The set pressure difference threshold is obtained by calibrating the DPF pressure difference under various working conditions. When the DPF pressure difference exceeds the set pressure difference threshold under the current working condition, it means that the DPF carbon load reaches the regeneration value.

3. The DPF regeneration control method according to claim 1, wherein: The turbine pre-pressure threshold is obtained by calibrating the turbine pre-pressure under various working conditions of the regenerated DPF carbon load.

4. The DPF regeneration control method according to claim 1, wherein: The DPF differential pressure is obtained by a DPF differential pressure sensor.

5. The DPF regeneration control method according to claim 1, wherein: When the DPF pressure difference is not greater than the set pressure difference threshold, driving regeneration is not performed.

6. The DPF regeneration control method according to claim 1, wherein: The turbine pre-pressure is obtained through a turbine pre-pressure sensor.

7. The DPF regeneration control method according to claim 6, wherein: Before obtaining the pre-turbocharger pressure, first determine whether there is a fault in the pre-turbocharger pressure sensor. If there is a fault, directly perform driving regeneration. If there is no fault, obtain the pre-turbocharger pressure.

8. The DPF regeneration control method according to claim 1, wherein: If the proportion of operating conditions with an air-fuel ratio less than 1.5 within one hour is no more than 50%, driving regeneration will not be performed.

9. The DPF regeneration control method according to claim 1, wherein: The judgment value of the pressure difference fluctuation and the judgment value of the air-fuel ratio are both empirical values.

10. A DPF regeneration control system, characterized in that: include: The first judgment module is configured to: obtain the DPF pressure difference in real time, and when the DPF pressure difference is greater than a set pressure difference threshold, detect whether there is a pressure difference sensor fault and whether the pressure difference fluctuation is less than 10hPa; The second judgment module is configured to: if there is no pressure difference sensor fault and the pressure difference fluctuation is less than 10hPa, open the exhaust throttle valve; otherwise, determine whether the proportion of operating conditions in which the air-fuel ratio is less than 1.5 within one hour is greater than 50%; The driving regeneration trigger judgment module is configured to: if so, also open the exhaust throttle valve and judge whether the pre-turbocharger pressure is greater than the pre-turbocharger pressure threshold; if so, perform driving regeneration; otherwise, do not perform driving regeneration.

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