Fuel Level Sensor Diagnosis Dead Zone Thresholds
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Solution Overview
Problem
Conventional failure diagnosis apparatuses for fuel level sensors may incorrectly determine sensor failure due to a 'dead zone' range where output values change minimally, leading to erroneous determinations during fuel consumption.
Innovation Solution
A failure diagnosis apparatus that classifies fuel remaining quantity ranges based on the fuel level sensor's output characteristics and adjusts failure determining thresholds for each range, including setting a specific threshold for the dead zone range to prevent erroneous determinations by ensuring accurate diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed failure determining threshold value is used for fuel level sensor diagnosis, then the diagnosis method is simple, but erroneous determination occurs in dead zone ranges where output values change minimally
Solution Approach 1:
The patent divides the fuel remaining quantity range into multiple segments (first range, second range, third range) based on the sensor's output characteristics. Each segment has its own failure determining threshold value, allowing accurate diagnosis across different operating conditions including dead zone ranges where the sensor output changes minimally.
Solution Approach 2:
The patent makes the failure determining threshold value dynamic by adjusting it according to the current fuel remaining quantity range. The threshold changes from a first threshold in the first range, to a second threshold in the second range (dead zone), to a third threshold in the third range, enabling the diagnosis system to adapt to varying sensor characteristics.
2Reliability
If the failure determining threshold is adjusted for each range, then diagnosis accuracy improves, but the diagnosis system becomes more complex
Solution Approach 1:
The patent segments the fuel quantity range into distinct zones with different threshold values, which improves diagnosis accuracy while keeping the complexity manageable through clear segmentation boundaries based on sensor output characteristics.
Solution Approach 2:
The patent changes the threshold parameter according to the operating range, setting different failure determining thresholds for different fuel remaining quantity ranges. This allows accurate diagnosis in dead zone ranges while maintaining a systematic approach that limits complexity.
Data Source
AI summary
A failure diagnosis apparatus for a fuel level sensor that detects a fuel remaining quantity within a fuel tank including at least a first tank and a second tank includes: a range deter mining unit for determining a range of a fuel remaining quantity on the basis of an output value of the fuel level sensor, the range being classified into a plurality of ranges in accordance with an output characteristic of the fuel level sensor; and a range failure diagnosis unit for carrying out failure diagnosis of the fuel level sensor for each range by comparing a fuel consumption quantity since the ranges are changed with a failure determining threshold value individually set up for each range. In a dead zone range in which a change in the output value of the fuel level sensor becomes small when a fuel consumer is switched from the first tank to the second tank, the range failure diagnosis unit sets the failure determining threshold value to a value corresponding to a fuel consumption quantity required to pass through the dead zone range.