Urea Pump Pressure Correction for Consumption Deviation Detection
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Solution Overview
Problem
Current methods for diagnosing urea consumption deviation in vehicle after-treatment systems lack versatility due to varying urea tank shapes, requiring calibration for each shape, which complicates the diagnosis of actual versus theoretical urea consumption.
Innovation Solution
A method involving the calculation of a pump pressure correction factor and urea consumption deviation factor, which adjusts for the characteristics of the urea injection system, allowing for the detection of deviations without recalibrating for different tank shapes, by adjusting pump pressures and duty cycles to determine if the nozzle is blocked or the orifice is enlarged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid level change of urea tank is used to diagnose urea consumption deviation, then the diagnosis can be implemented, but different tank shapes require separate calibration which reduces versatility
Solution Approach 1:
The patent changes the measurement parameter from liquid level (which varies with tank shape) to pump pressure (which is independent of tank shape). By monitoring pump pressure changes during urea injection and comparing actual consumption with theoretical consumption, the system achieves universal applicability across different tank configurations while maintaining diagnostic precision.
2Adaptability or versatility
If pump pressure is monitored to detect urea consumption deviation, then versatility is improved, but additional correction calculations are required
Solution Approach 1:
The system implements feedback by continuously monitoring pump pressure, calculating actual urea consumption based on pressure changes, comparing it with theoretical consumption values, and generating diagnostic feedback when deviations exceed thresholds. This closed-loop approach automates the correction process and reduces manual calibration complexity.
Solution Approach 2:
The patent replaces manual calibration procedures with automated electronic calculations. The control unit automatically performs the correction calculations by processing pump pressure signals and comparing consumption data, eliminating the need for manual intervention and reducing operational complexity.
3Measurement precision
If multiple calculations are performed to improve accuracy of urea consumption deviation detection, then measurement precision is improved, but calculation time increases
Solution Approach 1:
The system performs preliminary calibration during the manufacturing process, storing reference data in the control unit. During operation, it only needs to retrieve and compare against these pre-stored values, significantly reducing real-time calculation time while maintaining high diagnostic accuracy.
Data Source
AI summary
A method for detecting a urea consumption deviation including: calculating a pump pressure correction factor fac; calculating a urea consumption deviation factor A when the pump pressure correction factor fac is within a calibrated range; calculating the urea consumption deviation factor A multiple times, and calculating an average value of A; and comparing the average value of the urea consumption deviation factor A with a calibrated limiting value range, so as to determine whether there is a great deviation between an actual urea consumption value and a theoretical urea consumption value, the calculating the pump pressure correction factor fac comprises: adjusting a pressure of a urea pump to P1; adjusting the pressure of the urea pump to P2, where P2 is smaller than P1; recording a time T1 during which the pressure of the urea pump is adjusted from P1 to P2; and calculating fac=T1/(P1−P2).