Urea Tank Monitoring for SCR System Manipulation Detection

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Solution Overview

Problem

Existing methods for ensuring sufficient injection of urea-water mixture into vehicle exhaust systems to reduce nitrogen oxides under EURO VI emissions standards are inadequate, leading to potential underuse or manipulation, which can result in insufficient pollutant reduction.

Innovation Solution

An operating method that determines the filling level of the urea-water mixture at two points in time, calculates the difference to estimate realistic consumption, compares it to a reference quantity based on exhaust gas values and operating parameters, and activates vehicle restrictions if consumption falls below the target, thereby ensuring adequate injection and reducing pollutant emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the urea-water mixture is injected into the exhaust system to reduce nitrogen oxides, then pollutant reduction is improved, but the risk of underuse or manipulation increases leading to insufficient injection

Engineering Contradiction:
Improvenitrogen oxide emissionsVSAvoidinjection sufficiency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system continuously monitors the filling level of the urea-water mixture tank and compares actual consumption against reference consumption values. When manipulation or underuse is detected through discrepancies between expected and actual consumption patterns, the system provides feedback by activating operating restrictions to ensure compliance and prevent harmful emissions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system pre-calculates reference consumption values based on engine operating parameters and exhaust gas conditions before actual injection occurs. By establishing expected consumption thresholds in advance, the system can proactively detect deviations indicating manipulation or insufficient injection, allowing preventive action before emissions standards are violated.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If operational restrictions are activated to prevent manipulation, then injection reliability is improved, but vehicle performance is reduced

Engineering Contradiction:
Improveinjection complianceVSAvoidvehicle performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The operating restrictions are dynamically activated and deactivated based on real-time monitoring of consumption patterns. When manipulation or underuse is detected, restrictions such as power reduction or speed limiting are automatically imposed. Once compliance is restored, the system dynamically adjusts to恢复正常 performance, allowing the vehicle to operate at full capability when no violations occur.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the filling level is continuously monitored to detect manipulation, then detection accuracy is improved, but measurement precision requirements increase

Engineering Contradiction:
Improvefilling level detectionVSAvoidmonitoring system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the existing fuel tank filling level sensor as an intermediary measurement device rather than implementing a dedicated urea tank monitoring system. By leveraging the already-present sensor infrastructure and comparing actual consumption against calculated reference values based on engine parameters, the system achieves reliable detection without requiring additional complex measurement equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2562376B1Operating method for a vehicle
Publication Date: 2019.06.05 MAN TRUCK & BUS SE
  • EP2562376B1 patent drawingFigure 1
  • EP2562376B1 patent drawingFigure 2
  • EP2562376B1 patent drawingFigure 3

AI summary

The method involves determining (S1) filling value of urea containing liquid in a container of vehicle at two different points of time. The difference between filling values in different points of time is determined (S2) with respect to a reference amount, to achieve liquid decrease between points of time in close-to-reality. The reduction of pollutants in exhaust gas of vehicle is determined to restrict (S4) the vehicle operation, if the liquid decrease falls below reference amount over a preset size and/or over a defined time domain.