Reducing Agent Clogging Detection via Pump Duty Control
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Solution Overview
Problem
The existing exhaust gas purification systems face challenges in accurately detecting clogging in reducing agent supply devices, which can lead to inefficient maintenance and potential NOx emission due to unclear clogging locations in supply or return lines.
Innovation Solution
A clogging determining device and method that utilize pump DUTY control, pressure sensors, and DUTY determining means to calculate pressure reduction amounts, allowing for accurate detection of clogging in reducing agent passages and efficient repair or exchange by identifying clogged locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors and pump DUTY control are used to detect clogging, then measurement precision of clogging detection is improved, but device complexity increases
Solution Approach 1:
The system uses pump DUTY control with feedback from pressure sensors to detect clogging. The control unit monitors the relationship between pump driving DUTY and pressure sensor readings, and when abnormality is detected (e.g., pressure not decreasing as expected when pump stops), clogging is determined. This feedback mechanism enables accurate clogging detection without requiring additional complex hardware.
Solution Approach 2:
The existing pump and pressure sensor system is utilized for dual purposes: normal pressure control and clogging detection. The pump's own operating parameters (DUTY cycle) and the pressure sensor readings serve the additional function of diagnosing clogging, eliminating the need for separate dedicated detection hardware and reducing overall system complexity.
2Measurement precision
If each line is checked manually to locate clogging, then measurement precision of clogging location is improved, but loss of time increases
Solution Approach 1:
The manual mechanical inspection process is replaced with an automated diagnostic system using pressure sensors and pump control. The system automatically determines clogging location by analyzing pressure changes during pump operation cycles, eliminating the need for manual line-by-line checking and significantly reducing maintenance time while maintaining accurate location identification.
Solution Approach 2:
The system performs preliminary diagnostic actions by monitoring pressure changes during normal pump operation and dedicated test cycles. By proactively detecting pressure anomalies before failure occurs and automatically identifying the affected line, the system prepares maintenance information in advance, eliminating the need for time-consuming manual inspection when clogging actually occurs.
Data Source
AI summary
There are provided a clogging determining device for a reducing agent passage and a clogging determining method for a reducing agent passage, which can accurately detect clogging and estimate a clogged place when clogging occurs in any place of a supply line or a return line.The device includes pump driving control element for subjecting the pump to DUTY control so that a pressure value is kept to a predetermined value, driving DUTY determining element for determining whether the driving DUTY of the pump is less than a predetermined threshold value corresponding to the opening degree of the reducing agent injection valve, or not; pressure reduction amount calculating element for calculating a pressure reduction amount by which the pressure value detected by the pressure sensor is reduced within a predetermined time after the pump is stopped and the reducing agent injection valve is fully opened when it is determined that the driving DUTY of the pump is less than the threshold value, and clogging determining element for determining on the basis of the pressure reduction amount calculated by the pressure reduction amount: calculating element whether clogging occurs in the first reducing agent passage or the second reducing agent passage.