Quality Sensor Clock Signal Diagnosis for Urea Metering
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Solution Overview
Problem
Existing methods for diagnosing the quality of urea/water solutions in reagent metering systems for internal combustion engines, used to reduce NOx emissions, fail to accurately detect deviations in urea concentration and potential manipulation, leading to suboptimal NOx reduction and potential fraud detection.
Innovation Solution
A method utilizing a quality sensor with a signal-processing arrangement that includes a clock generator to ascertain a time-based quality signal, transmitted via an interface, allowing for evaluation of clock signal period duration against threshold values to diagnose faults and ensure accurate urea concentration measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quality sensor with time-based measurement is used to detect urea concentration, then measurement precision is improved, but device complexity increases due to the need for clock signal evaluation and period duration analysis
Solution Approach 1:
The patent introduces a clock signal as an intermediary element that mediates between the quality sensor's time-based measurement and the control device's evaluation system. The clock signal with its specific period duration serves as a carrier that encodes quality information, allowing precise measurement while simplifying the overall system architecture by providing a standardized interface for data transmission and evaluation
2Reliability
If the quality sensor transmits data depending on clock signal period duration, then reliability of data transmission is improved, but difficulty of detecting and measuring increases due to the need for period duration analysis
Solution Approach 1:
The patent utilizes parameter changes in the clock signal, specifically the period duration, to encode quality information. By varying the clock signal's temporal parameters based on the measured quality characteristics, the system achieves reliable data transmission while enabling straightforward detection through period duration measurement and comparison against threshold values
3Reliability
If on-board diagnosis is implemented to detect fraud and ensure compliance, then reliability of emission control is improved, but device complexity increases due to additional diagnostic functions
Solution Approach 1:
The patent implements a self-service diagnostic system where the quality sensor and control device work together to automatically monitor, evaluate, and diagnose the urea solution quality. The system performs self-verification by comparing clock signal period durations against threshold values and automatically generates fault signals when deviations are detected, enabling reliable fraud detection and compliance assurance without requiring complex external diagnostic equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective on-board diagnosis of the quality sensor, ensuring proper urea concentration measurement and preventing NOx reduction inefficiencies and fraud by identifying deviations in the clock signal period duration, thus maintaining compliance with emission standards.
Implementation Method 1
the quality sensor contains a signal-processing arrangement with a clock generator which provides a clock signal, in that the quality sensor ascertains the quality signal with a time-based measurement on the basis of a clock signal
Data Source
AI summary
A method for diagnosing a quality signal (26). The quality signal (26) is provided by a quality sensor (24) used in a reagent metering system (10). The reagent metering system (10) meters a urea/water solution (14) stored in a tank (12), the quality of which is checked by the quality sensor (24), upstream of an SCR catalytic converter (20).