Tank having a sensor for determining the fill level
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Solution Overview
Problem
Existing systems for determining the fill level of urea-water solutions in reducing agent tanks, particularly in vehicles, face challenges at low temperatures where the solution can freeze, leading to unreliable delivery and the need for a simple, cost-effective sensor system to ensure exhaust gas treatment effectiveness.
Innovation Solution
A tank design with a sensor system featuring electrical contacts that penetrate the tank wall, allowing for conductance measurements between them to determine the presence and state (liquid or frozen) of the reducing agent, with optional heater integration for ice cave detection and temperature monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex continuous level determination processes are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor system is segmented into multiple discrete electrical contacts (first electrical contact, second electrical contact, third electrical contact) arranged at different heights on the tank wall. Each contact pair can independently detect fill level at specific thresholds, providing continuous level determination through discrete measurement points rather than a single complex continuous sensor.
Solution Approach 2:
The patent uses the reducing agent solution itself as an intermediary medium for measurement. By utilizing the electrical conductivity properties of the liquid reducing agent between the electrical contacts, the system achieves simple yet accurate level detection without requiring complex external sensing mechanisms. The solution between which the first electrical contact and the second electrical contact are arranged serves as the measurement medium.
2Device complexity
If low-cost simple sensor systems are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The tank wall is segmented with multiple electrical contacts positioned at specific vertical intervals. This segmentation allows simple discrete electrical contacts to collectively provide precise continuous level measurement by detecting which contacts are immersed in the reducing agent solution.
Solution Approach 2:
The system changes the measurement parameter from complex physical measurements to simple electrical conductivity detection. By arranging multiple electrical contacts at different heights and detecting their conductivity state relative to the reducing agent solution, the system achieves accurate reserve level determination using simple, low-cost electrical sensing.
3Manufacturing precision
If electrical contacts are arranged at large distances, then manufacturing precision is reduced, but measurement coverage is improved
Solution Approach 1:
The measurement range is segmented into multiple zones by distributing electrical contacts at different heights on the tank wall. This segmentation allows each contact pair to cover a specific measurement zone, providing accurate overall fill level determination through the combination of discrete contact measurements rather than requiring high precision in single large-spacing contacts.
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
This solution provides reliable and accurate fill level determination, including reserve levels, even at low temperatures, reducing errors and ensuring continuous exhaust gas treatment functionality.
Implementation Method 1
A sensor (5) having a first electrical contact (6) and a second electrical contact (7) is arranged on the tank wall (3), with the first electrical contact (6) and the second electrical contact (7) being in electrically conductive connection with the interior, penetrating the tank wall from the interior to an outside of the tank wall
Implementation Method 2
A device for delivering or metering liquid reducing agent is then no longer able to deliver the urea-water solution at temperatures of -11 °C or below
Data Source
Figure 1~3
Figure 4~7
Figure 8~10
AI summary
The invention relates to a tank (1) for a reducing agent, comprising a tank wall (3) and an interior (4) at least partially bounded by the tank wall (3). A sensor (5) having a first electrical contact (6) and a second electrical contact (7) is disposed on the tank wall, wherein the first electrical contact (6) and the second electrical contact (7) are electrically conductively connected to the interior (4), penetrate the tank wall (3) from the interior (4) to an outer face (8) of the tank wall (3), and are disposed at a first distance (9) of less than 5 cm from each other.