Urea concentration fault detection method and device, control equipment and storage medium

Abstract

The invention provides a urea concentration fault detection method and device, control equipment and a storage medium. The method comprises steps of judging whether a selective catalytic reduction system has the fault of low nitrogen oxide conversion efficiency or not; if yes, spraying urea according to a preset first urea ammonia nitrogen ratio, and storing first conversion efficiency of nitric oxide of the selective catalytic reduction system; spraying urea according to a preset second urea ammonia nitrogen ratio, and storing second conversion efficiency of nitrogen oxide of the selective catalytic reduction system; judging whether the first conversion efficiency and the second conversion efficiency are lower than a first preset threshold value or not; if so, determining that the fault is caused by low urea concentration. According to the embodiment of the invention, when the fault that the NOx conversion efficiency of a SCR system is low is detected, the SCR system fault caused by low urea concentration is accurately judged by comparing the distribution conditions of the NOx conversion efficiency when urea is injected at different ammonia-nitrogen ratios, and the risk of false alarm is reduced.

Description

technical field [0001] The invention relates to the technical field of engine detection, in particular to a urea concentration fault detection method, device, control equipment and storage medium. Background technique [0002] Selective Catalyst Reduction (SCR) technology is aimed at reducing nitrogen oxides (NO) in exhaust emissions from diesel vehicles. x A treatment process, that is, under the action of a catalyst, the reducing agent ammonia or urea is injected to reduce the nitrogen oxides NO in the tail gas x reduced to N 2 and H 2 O. [0003] In the prior art, when a fault with low nitrogen oxide conversion efficiency in the SCR system is usually detected, it is indirectly indicated that it is caused by low urea concentration, but the deterioration of the SCR system may also lead to low nitrogen oxide conversion efficiency, that is, It is said that the existing technology cannot distinguish whether the failure causing the low nitrogen oxide conversion efficiency of...

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Problems solved by technology

[0003] In the prior art, when a fault with low nitrogen oxide conversion efficiency in the SCR system is usually detected, it is indirectly indicated that it is caused by low urea concentration, but the deterioration of the SCR system may also lead to low nitrogen oxide conversion efficiency, that is, Said that the existing technology cannot distinguish whether the failure that causes the low nitrogen oxide conversion efficiency of the SCR system is caused by low urea concentration or the deterioration of the SCR system, and there is a risk of false alarms

[0004] Therefore, there is an urgent need for a urea concentration fault detection method to solve the risk of false positives in the prior art

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