Fluid Level Determination Using Discrete Sensor Signal Counting
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Solution Overview
Problem
Internal combustion engines equipped with discrete level sensors face challenges in accurately determining fluid levels, especially during transitory driving conditions due to sloshing, which leads to misleading information and reduced precision.
Innovation Solution
A method that utilizes a discrete level sensor to generate electrical signals based on predetermined threshold values, monitors these signals over a time interval, and calculates the fluid level as a weighted average of these signals, discarding sporadic occurrences to filter out sloshing effects, using the Electronic Control Unit's computational capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discrete level sensors are used to detect fluid level, then cost is reduced compared to continuous sensors, but measurement precision deteriorates because they cannot detect precise level between threshold values
Solution Approach 1:
The system performs preliminary actions by monitoring and counting signal occurrences over a time interval before calculating the final fluid level. This preliminary monitoring phase captures multiple threshold exceedance events, which are then processed to determine the actual fluid level, thereby improving precision while using discrete sensors.
Solution Approach 2:
The system maintains continuous monitoring of threshold signals over a defined time interval, continuously counting occurrences and updating the fluid level calculation. This continuous action ensures accurate fluid level determination despite the discrete nature of the sensor, resolving the precision-cost contradiction.
2Device complexity
If discrete level sensors are used in transitory driving conditions, then device complexity is reduced, but reliability deteriorates due to sloshing causing random threshold exceedance and conflicting information
Solution Approach 1:
Before calculating the final fluid level, the system performs preliminary monitoring and counting of signal occurrences over a time interval. This preliminary phase filters out random sporadic signals caused by sloshing, ensuring that only consistent threshold exceedances contribute to the final calculation, thereby improving reliability during transitory conditions.
Solution Approach 2:
The system uses multiple threshold values (first, second, and third thresholds) rather than a single threshold, and monitors occurrences partially over a time interval rather than instantaneously. This partial/excessive approach allows the system to distinguish between genuine level changes and sloshing-induced false signals, improving reliability while maintaining simple device architecture.
3Measurement precision
If multiple threshold values are monitored over time, then fluid level determination precision is improved, but loss of time increases due to monitoring over a time interval
Solution Approach 1:
The system monitors threshold signals partially over a defined time interval rather than continuously indefinitely. By selecting an appropriate time interval duration and monitoring multiple thresholds (first, second, third) within this interval, the system achieves precise fluid level determination while minimizing time loss, balancing precision and time efficiency.
Data Source
AI summary
A method for determining a fluid level value in a fluid tank of an internal combustion engine equipped with a discrete level sensor is provided. The discrete level sensor is configured for generating a first electrical signal when a fluid level is above or equal to a first predetermined fluid level threshold value and generating a second electrical signal when the fluid level is above or equal to a second predetermined fluid level threshold value. The second predetermined fluid level threshold value is greater than the first predetermined fluid level threshold value. The method includes monitoring a number of occurrences of the first electrical signal and of the second electrical signal over a time interval. The fluid level in the fluid tank is calculated as a function of the number of occurrences of the first and of the second electrical signals over the time interval.