Method for diagnosing health state of liquid reducing agent supply pump

Abstract

The invention discloses a method for diagnosing the health state of a liquid reducing agent supply pump. The method comprises the following steps: 101, calculating a standard control parameter threshold value in a determined health state according to the supply voltage of the supply pump under the condition that the calculation condition is met; 102, calculating a control parameter capable of representing the actual health state of the supply pump when the working state of the supply pump meets a set condition; 103, determining the actual health condition of the supply pump according to the deviation between the control parameter for the actual health condition of the supply pump calculated in the step 102 and the standard control parameter threshold value under the determined health condition calculated in the step 101; and 104, determining the cause of the failure according to the actual health condition of the supply pump and deviation of the health control parameters calculated instep 103, and reporting the cause to a supply pump control unit. The health state of the reducing agent supply pump can be monitored in real time, diagnosis is reliable, and no extra cost is needed.

Description

technical field [0001] The invention relates to the technical field of aftertreatment of internal combustion engines, in particular to a method for diagnosing the health state of a liquid reductant supply pump. Background technique [0002] Vehicle systems include vehicles powered by diesel engines. Diesel engines occupy an absolute dominance in the field of commercial vehicles due to their low fuel consumption and strong power. However, the particulate pollutants PM and toxic gas components NOx emitted by them have always been criticized. . With the continuous upgrading of diesel vehicle emission requirements in my country, selective catalytic reduction system (SCR) has become the standard configuration of diesel engine exhaust treatment system, in which the reductant supply pump plays a basic role as the core component of the SCR system, which is responsible for the liquid reductant (Ammonia water or urea) is absorbed from the storage tank, raised to the set pressure and m...

AI Technical Summary

Problems solved by technology

[0003] The system health status diagnosis method provided by the current selective catalytic reduction system usually monitors the basic work function of the supply pump. When the supply pump fails, the OBD (On Board Diagnosis) system of the diesel engine issues a fault report and performs torque limit or shutdown operations. Lack of certain failure predictability, that is, the system does not give users a reminder during the long-term running period when the system transitions from aging to failure. The supply pump failure reported by the OBD system is sometimes caused by very simple reasons. However, if the user sends the vehicle to the after-sales service center for processing, it will be time-consuming and labor-intensive; in addition, the existing supply pump diagnosis method usually uses the same diagnosis method and diagnosis threshold and lacks individualized diagnosis of a single product. In large-scale industrial production, due to manufacturing and assembly errors, there are certain differences in the characteristics of a single supply pump. Using the same diagnostic threshold may lead to misjudgment or missed judgment of faults, which limits the effectiveness of existing diagnostic algorithms to a certain extent. Application range

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