Tank Level Sensor Signal Correction via Fuel Consumption Calculation
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Solution Overview
Problem
Conventional tank fuel level sensors using potentiometer devices suffer from dead-center position limitations, corrosion issues, and reduced accuracy, especially with ethanol-based fuels, leading to unreliable fuel level detection that can affect engine control and driver estimation of cruising range.
Innovation Solution
A method that utilizes existing vehicle components to smooth, filter, and linearize the tank level sensor signal, using fuel consumption calculations and engine operating conditions to provide a corrected and reliable tank level signal, detecting malfunctions and improving accuracy without additional sensors or costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a potentiometer-based tank level sensor with lever arm and float gauge is used, then the device complexity is low and cost is reduced, but the measurement precision deteriorates due to dead-center positions and dead volumes
Solution Approach 1:
The patent introduces an intermediary calculation method that uses fuel consumption data from the engine control unit to compute a theoretical tank level. This calculated tank level serves as a mediator to correct the raw sensor signal from the potentiometer, compensating for dead-center position errors and dead volume detection failures without changing the mechanical sensor structure.
Solution Approach 2:
The patent replaces the mechanical lever arm limitation with an electronic calculation approach. Instead of relying on the mechanical lever to physically indicate the true tank level, the system uses electronic computation of fuel consumption to determine the actual tank level, substituting the mechanical indication system with an electronic correction algorithm.
2Ease of manufacture
If a potentiometer-based tank level sensor is used, then the ease of manufacture is improved, but the reliability deteriorates due to corrosion on the potentiometer path
Solution Approach 1:
The patent implements a feedback mechanism where the calculated tank level (based on fuel consumption) continuously corrects the raw sensor signal. This feedback loop compensates for corrosion-induced drift in the potentiometer readings, maintaining reliability without requiring corrosion-resistant materials or protective coatings on the potentiometer.
3Productivity
If the tank level sensor signal is used directly for engine control functions, then the productivity is maintained, but the reliability of exhaust gas control deteriorates due to sensor malfunctions
Solution Approach 1:
The patent performs preliminary correction of the tank level signal by calculating the expected tank level from fuel consumption before using it for exhaust gas control functions. This preliminary action ensures that the control system receives a reliable tank level value that has already been corrected for sensor errors, preventing propagation of errors to exhaust gas control.
Data Source
AI summary
A method for detecting the tank fuel level of a motor vehicle includes: ascertaining the tank level sensor signal (UTSG) of a tank level sensor, determining a calculated tank level (Fcalc) as a function of a fuel quantity consumed by the internal combustion engine, and providing a corrected tank level signal as a function of the tank level sensor signal (UTSG) and the calculated tank level (Fcalc).