SCR conversion efficiency recovery method and device and vehicle

Abstract

The invention discloses an SCR conversion efficiency recovery method and device and a vehicle, and is used for improving the SCR conversion efficiency of a vehicle after-treatment system. The vehicle after-treatment system comprises an SCR device and a DPF; the vehicle after-treatment system pre-stores an SCR conversion efficiency pulse spectrum; the method comprises the steps that the first conversion efficiency of the SCR device under the current exhaust gas flow and exhaust gas temperature is obtained; according to the SCR conversion efficiency pulse spectrum, the first conversion efficiency threshold value and the first conversion efficiency in the SCR conversion efficiency pulse spectrum under the current waste gas flow and the current waste gas temperature are compared; and if the first conversion efficiency is lower than the first conversion efficiency threshold value, the DPF is controlled to execute active regeneration. According to the technical scheme, active regeneration is triggered in advance when the SCR conversion efficiency is reduced but no NOx exceeding 1.2 fault occurs, so that the problem of low SCR conversion efficiency can be solved, DPF overload blockage faults can be reduced, the labor cost can be saved, and the economic benefit can be improved.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a method, a device and a vehicle for recovering SCR conversion efficiency. Background technique [0002] In the current National VI diesel engines on the market, due to frequent problems such as selective catalytic reduction SCR (Selective Catalytic Reduction) device crystallization, urea nozzle crystallization, and sulfur poisoning of after-treatment devices, the conversion efficiency of after-treatment often decreases, and nitrogen oxides NO x Emission exceeds the standard, causing NO x Exceeding 1.2 faults; in addition, due to the calculation deviation of the carbon load model and the measurement error of the differential pressure sensor, etc., it is easy to cause the particle filter DPF (Diesel Particulate Filter) to overload and block the fault. [0003] In the prior art, usually when NO x After the discharge exceeds the standard fault, the maintenance service personnel pe...

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Problems solved by technology

[0004] The embodiment of the present invention provides a method, device and vehicle for recovering SCR conversion efficiency. When the SCR conversion efficiency decreases but no NO occurs x When the fault exceeds 1.2, the active regeneration is triggered in advance, which can not only effectively solve the problem of low SCR conversion efficiency, reduce the occurrence of DPF overload blockage, but also save labor costs and facilitate vehicle maintenance services, which has huge market potential and economic benefits

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