Method and device for detecting filtering capacity of DPF

Abstract

The invention provides a method and device for detecting the filtering capacity of a DPF. The method comprises the steps that a pipeline air leakage correction factor is pre-calculated and obtained, adifferential pressure sensor collected value is corrected through the pipeline air leakage correction factor, and a corrected differential pressure value is obtained. Due to the fact that the corrected differential pressure value corrects differential pressure influence caused by pipeline air leakage, whether the filtering capacity of the DPF is normal or not is determined according to the relation between the corrected differential pressure value and a differential pressure lower limiting value, so that the detecting result is more accurate, the fault false alarm rate caused by the pipelineair leakage is reduced, and the robustness of a detecting strategy is improved. Furthermore, by setting differential pressure self-learning conditions, when a vehicle meets the differential pressure self-learning condition, the pipeline air leakage correction factor is calculated, and the workload of pre-calibrating the corresponding relation among the waste volume flow rate, DPF temperature and standard differential pressure and the corresponding relation between a relative error and the pipeline air leakage correction factor is reduced.

Description

technical field [0001] The invention relates to the field of post-processing systems, and more specifically, to a method and device for detecting the filtering capacity of a DPF. Background technique [0002] Due to emission regulations, aftertreatment systems need to be installed in diesel vehicles. In the aftertreatment system, it is necessary to use DPF (Diesel Particulate Filter, particle trap) to reduce engine particle emissions. When the particles accumulate to a certain value, the DPF needs to be regenerated. During the regeneration process, the DPF is easily burnt due to overheating, resulting in a decrease in the DPF’s filtration capacity. [0003] At present, diesel vehicles adopt a monitoring strategy based on differential pressure sensors to monitor the DPF's ability to filter particles. Specifically, the differential pressure value detected by the differential pressure sensor is compared with the lower limit value of the differential pressure to determine the ...

AI Technical Summary

Problems solved by technology

However, the inventors found that due to pipeline leakage and other reasons, there is a large deviation in the pressure difference collection value between different vehicles at the same working point, and between the vehicle and the bench, which leads to the robustness of the monitoring strategy on the vehicle. The performance is reduced, and it is easy to cause false alarms

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