O2 Sensor Fuel Shortage Detection via Lean-State Accumulation
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Solution Overview
Problem
Existing fuel shortage detection methods for internal combustion engines are inaccurate due to the transient nature of the air-fuel ratio and engine rotation fluctuations, leading to false determinations of fuel shortage.
Innovation Solution
A fuel shortage detection device that utilizes an O2 sensor to detect the air-fuel ratio, calculates accumulated time of lean states, and incorporates rotation speed and fuel tank level sensors to confirm fuel shortage, resetting intervals to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the air-fuel ratio detection method is used to detect fuel shortage, then the detection can identify lean states, but false positives occur when the lean state is temporary and not caused by actual fuel shortage
Solution Approach 1:
The system performs preliminary actions by accumulating lean state detection results over multiple determination cycles before declaring fuel shortage. The accumulated time calculation section tracks how long the lean state persists, and only triggers fuel shortage determination when the accumulated time exceeds a threshold, preventing premature false positives from temporary lean states
Solution Approach 2:
The system implements periodic determination cycles where the air-fuel ratio is evaluated at regular intervals. By resetting the accumulated time at each cycle and requiring the lean state to persist across multiple cycles, the system filters out transient conditions and reliably identifies sustained fuel shortage conditions
2Reliability
If the detection system continuously monitors air-fuel ratio, then it can detect fuel shortage conditions, but the transient nature of air-fuel ratio causes false determinations
Solution Approach 1:
Before making a final fuel shortage determination, the system performs preliminary accumulation of lean state evidence over multiple determination cycles. The accumulated time calculation section builds up confidence in the detection by tracking the duration of lean states, ensuring that temporary fluctuations do not trigger false positives
Solution Approach 2:
The system uses feedback from continuous air-fuel ratio monitoring to adjust its determination. By feeding back the accumulated time information and comparing it against thresholds, the system refines its detection accuracy, maintaining high reliability while avoiding false determinations from transient conditions
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
Enhances the detection of fuel shortage by minimizing false positives through combined sensor data analysis, ensuring reliable fuel level determination.
Implementation Method 1
an O2 sensor arranged in an exhaust passage of the internal combustion engine that detects an oxygen concentration of a gas flowing in the exhaust passage
Data Source
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AI summary
A fuel shortage detection device for an internal combustion engine capable of detecting fuel shortage based on the air-fuel ratio of the exhaust gas. The fuel shortage detection device for an internal combustion engine includes: an air-fuel ratio determination section 61 that determines whether the air-fuel ratio of the exhaust gas is equal to or greater than a first threshold value TH1 based on the detection result of an O2 sensor 78; an accumulated time calculation section 62 that calculates an accumulated time Ta, which is an amount of time over which the air-fuel ratio is equal to or greater than the first threshold value TH1; an accumulated time reset section 63 that resets the accumulated time Ta at every predetermined time interval B; an accumulated time determination section 64 that determines whether the accumulated time Ta is greater than or equal to a second threshold value TH2; and a fuel shortage determination section 67 that determines that there is fuel shortage when the accumulated time Ta becomes equal to or greater than the second threshold value TH2.