Fault monitoring method and device for DPF

Abstract

The invention provides a fault monitoring method and device for a DPF. The method comprises the steps that state parameters of the DPF at the current moment are obtained; whether the state parameters meet a monitoring enabling condition or not are judged; if yes, a current differential pressure estimation value of the DPF is obtained based on a first initial differential pressure value and a second initial differential pressure value, wherein the first initial differential pressure value is obtained through calculation according to a differential pressure model, and the second initial differential pressure value is obtained through collection by a differential pressure collector arranged on the DPF; the differential pressure estimation value is compared with a corrected differential pressure lower limit value; if the differential pressure estimation value is smaller than the differential pressure lower limit value, it is determined that the DPF is in an initial abnormal state, and the duration of the DPF in the initial abnormal state is recorded; if the duration is greater than a preset duration threshold, updating the number of abnormal times; and if the updated abnormal frequency is larger than a preset frequency threshold value, it is determined that the DPF breaks down. By applying the method, the robustness of DPF monitoring can be improved.

Description

technical field [0001] The invention relates to the technical field of post-treatment of exhaust gas of an internal combustion engine, in particular to a DPF fault monitoring method and device. Background technique [0002] Particulate matter is one of the main pollutants in diesel engine exhaust emissions. At present, the most effective after-treatment device for reducing diesel engine particulate matter emissions is a wall-flow particulate filter (DPF). When the particulate matter captured by DPF reaches a certain limit, measures should be taken to clean up the particulate matter, that is, DPF regeneration. During the regeneration process, the DPF is likely to burn due to overheating, resulting in a decrease in the DPF filtration efficiency. Therefore, in order to ensure the normal operation of the DPF, it is necessary to monitor the DPF. [0003] In the prior art, by comparing the differential pressure value collected by the DPF differential pressure sensor with the lowe...

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Problems solved by technology

During the regeneration process, the DPF is likely to burn due to overheating, resulting in a decrease in the DPF filtration efficiency. Therefore, in order to ensure the normal operation of the DPF, it is necessary to monitor the DPF

[0003] In the prior art, by comparing the differential pressure value collected by the DPF differential pressure sensor with the lower limit value of the differential pressure, when the detected sensor collects When the pressure difference value is less than the lower limit value of the pressure difference, a DPF fault is reported. However, the accuracy of the existing DPF pressure difference sensor is about 5hPa, and the pressure difference range of the DPF is 0-60hPa in normal use. In general application conditions, the DPF is normal. The deviation of the parts and cracking parts is within 10hPa, so the robustness of the DPF filtration efficiency monitoring strategy is greatly reduced due to the low precision of the DPF differential pressure sensor

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