Method for fault diagnosis of post-processing structure and post-processing structure

Abstract

The present application relates to a method for fault diagnosis of a post-processing structure and a post-processing structure, and relates to the technical field of engine exhaust gas purification. The post-processing structure includes a particulate trap and a selective catalytic reduction device connected to the particulate trap through an exhaust pipe; The method includes the following steps: opening an inspection port on the exhaust pipe; setting a connecting cylinder on the inspection port so that the detection channel of the connecting cylinder communicates with the exhaust pipe; implanting a detection device in the detection channel so that the detection device Towards the selective catalytic reduction device; the selective catalytic reduction device is detected by the detection device to determine whether the selective catalytic reduction device is blocked by crystallization. It can directly and accurately diagnose whether a crystallization fault has occurred in the selective catalytic reduction device, and carry out targeted maintenance on the crystallization fault of the selective catalytic reduction device, which facilitates subsequent maintenance and reduces maintenance costs and time.

Description

technical field [0001] The present application relates to the technical field of engine exhaust gas purification, in particular to a method for fault diagnosis of an aftertreatment structure and an aftertreatment structure. Background technique [0002] With stricter requirements on particulate emissions and nitrogen oxides NOx emissions, in order to meet the specified emissions, the vehicle will be equipped with an after-treatment system. The after-treatment system consists of an oxidation catalyst DOC+particulate matter trap DPF+selective catalytic reduction device SCR+ammonia oxidation catalyst Composed of ASC, DPF is prone to carbon blockage and ash blockage during use, and SCR is prone to crystallization blockage during use. Both of these failures will lead to high exhaust back pressure of the engine and affect engine performance. However, because the performance of these two types of faults is the same, it is impossible to accurately distinguish between the two types o...

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Problems solved by technology

[0005] The embodiment of the present application provides a post-processing structure fault diagnosis method and a post-processing structure to solve the problem that in the related art, it is impossible to accurately diagnose whether the SCR crystallization fault occurs, but when the DPF is not blocked, it is directly considered as the SCR crystallization fault, and the SCR conducts crystalline fault repair, which leads to problems that the fault remains unresolved, the diagnosis time is too long, and the diagnosis cost is too high

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